Optical system for a virtual retinal display

Abstract

The invention relates to an optical system (1) for a virtual retinal display (retinal scan display), which has at least one illumination device (25). The illumination device (25) has at least one first laser diode (5) for emitting a first light beam (6) and / or a second laser diode (23) for emitting a second light beam (24). Alternatively or additionally, the optical system (1) has a controllable deflection unit as the first optical component for the first light beam (6) for scanning projection of the image content. Furthermore, the optical system (1) has a further optical component (8) for deflecting and / or transmitting the first light beam (6) onto a retina (2) of a user of the optical system (1). In addition, the optical system (1) has a light-absorbing component (9) for at least the first light beam (6) and / or the second light beam (24), as well as a control unit (20).The control unit (20) is designed to control the second laser diode (23) and / or the controllable deflection unit, depending on the condensation and / or frozen water detected on a first, in particular outer, surface of the controllable deflection unit and / or on a second, in particular outer, surface (26) of the further optical component (8), such that the first light beam (6) and / or the second light beam (24) is directed onto the light-absorbing component (9). The light-absorbing component (9) is thermally conductively connected to the first and / or second surface (26) covered by the condensation and / or frozen water detected.

Description

The invention relates to a state of the art

[0001] Data glasses (smartglasses) with retinal scan displays and holographic optical elements for redirecting light rays to the eye are already known.

[0002] It is an object of the present invention to develop an optical system for a virtual retinal display, the function of which remains fulfilled despite moisture condensation on the surfaces of the optical components of the optical system. Disclosure of the invention

[0003] To achieve this object, an optical system for a virtual retinal display (retinal scan display) according to claim 1 is proposed. Furthermore, a method for controlling a control unit of an optical system for a virtual retinal display (retinal scan display) according to claim 15 is proposed.

[0004] The optical system for a virtual retinal display (retinal scan display) has at least one illumination device, in particular a projector unit, of the optical system. The illumination device has at least one first laser diode for emitting a first light beam. Alternatively or additionally, the illumination device has a second laser diode for emitting a second light beam. Further alternatively or additionally, the optical system has a controllable deflection unit as the first optical component for the first light beam for scanning projection of the image content. In this context, the controllable deflection unit has, in particular, at least one micromirror, in particular a rotatably mounted one. Furthermore, the optical system has a further optical component for deflecting and / or transmitting the first light beam to a retina of a user of the optical system.In addition, the optical system has a light-absorbing component for at least the first light beam and / or the second light beam, as well as a control unit. The control unit is designed to control the second laser diode and / or the controllable deflection unit depending on detected condensation and / or frozen water on a first, in particular outer, surface of the controllable deflection unit and / or on a second, in particular outer, surface of the further optical component such that the first light beam and / or the second light beam is directed onto the light-absorbing component. The detected condensation and / or frozen water is arranged in particular in the light path of the first light beam to the user's retina. Furthermore, the light-absorbing component is thermally conductively connected to the first and / or second surface covered by the detected condensation and / or frozen water.By irradiating the light-absorbing component with the first and / or second light beam and by thermally conductively connecting the light-absorbing component to the first and / or second surface, condensation and / or frozen water located there is removed due to the heat generated and the optical function of the optical components is ensured.

[0005] Preferably, the further optical component is a lens of the optical system. Alternatively or additionally, the further optical component is an exit window of the first light beam from the optical system. In particular, the exit window is designed as a glass window on the outside of a temple of a data glasses as an optical system. Thus, the first light beam can be transmitted through the exit window toward the lens of the data glasses. Alternatively or additionally, the further optical component is designed as a lens.

[0006] Preferably, the optical system is designed as a pair of data glasses. Such data glasses allow data, in particular information, to be projected into the user's eye. In this case, it is particularly important that all optical components of the optical system function as intended.

[0007] Preferably, the optical system additionally comprises a sensor for detecting condensation and / or frozen water on the first and / or second surface. This is in particular a laser feedback interferometry sensor. The sensor is designed to forward the sensor signals to the control unit. In this context, the control unit is designed in particular to detect, depending on the forwarded sensor signals, whether condensation and / or frozen water is present on the surfaces and to control the second laser diode and / or the controllable deflection unit accordingly only if condensation and / or frozen water is present. Alternatively or additionally, the optical system additionally comprises an input means for the user of the optical system for generating an input signal if condensation and / or frozen water is present on the first and / or second surface.The input means is further configured to forward the input signal to the control unit. The user can thereby infer the presence of condensation and / or frozen water if the lenses are fogged with condensation and / or the optical system is currently malfunctioning. This embodiment offers the advantage that the control unit only controls the second laser diode and / or the controllable deflection unit when a real problem exists for the user of the optical system. Alternatively, the control unit is configured to control the controllable deflection unit such that the first light beam is directed at the light-absorbing component at specific time intervals.For this purpose, the control unit is particularly designed to control the controllable deflection unit such that the controllable deflection unit stops at specified positions and time intervals, so that the first light beam is directed onto the light-absorbing component. Alternatively or additionally, the control unit is designed in this context to control the controllable deflection unit such that the first light beam is directed onto the light-absorbing component for a specified time interval during each scan of the image content. This enables the simplest possible control of the controllable deflection unit.

[0008] Preferably, the second laser diode is permanently aligned with the light-absorbing component and thus serves solely to irradiate the light-absorbing component. In this context, the control unit is configured to switch on the second laser diode when condensation and / or frozen water is detected on the first surface of the controllable deflection unit and / or on the second surface of the further optical component, and to switch off the second laser diode if it is detected that no condensation and / or frozen water is present.

[0009] The light-absorbing component is preferably arranged outside the light path of the first light beam. This is, in particular, a first edge region of the controllable deflection unit and / or a second edge region of the further optical component. This offers the advantage that the light-absorbing component does not interfere with the scanning process of the image content. In this context, it is preferably provided that the light-absorbing component is arranged separately, in particular at a distance, from the controllable deflection unit and / or the further optical component. Alternatively, the light-absorbing component can also be arranged on the controllable deflection unit and / or the further optical component within the light path of the first light beam. This offers the advantage of the simplest and most advantageous heat conduction possible between the light-absorbing component and the first and / or second surface.

[0010] Preferably, the light-absorbing component is formed as a light-absorbing layer, in particular as a black paint layer or black lacquer layer. Alternatively, the light-absorbing component is formed as structures incorporated into the glass, in particular narrow-band structures, or as a light-absorbing glass material.

[0011] The light-absorbing component preferably absorbs light rays of at least one wavelength. In particular, it is provided that the light-absorbing component absorbs light rays of multiple wavelengths, in particular the wavelength of the first and second light beams. The first and / or second light beams are in particular designed as light beams with a green, red, blue, or infrared wavelength.

[0012] Preferably, the control unit is designed to control the first laser diode and / or the second laser diode depending on detected condensation and / or frozen water on the first surface of the controllable deflection unit and / or on the second surface of the further optical component such that the first and / or second light beam, when aligned with the light-absorbing component, is emitted with an increased laser power, in particular with a power of at least 10 mW. The increased laser power here means the laser power compared to the scanning process, in particular by means of the first light beam. During the scanning process, the laser power is limited within the scanning range due to the eye safety of the user of the optical system, and a maximum laser power of 0.4 mW is used.However, to generate sufficient heat energy, increased laser power can be used if the first light beam is directed at the light-absorbing component, provided the component is not located in the light path, especially the scanning area, of the first light beam. Thus, a shorter period of time is sufficient to generate sufficient heat energy to remove the condensation and / or frozen water. Since the second light beam is used only to irradiate the light-absorbing component and not to scan the image content, it can be directed at the light-absorbing component without limiting the laser power.

[0013] The optical system preferably comprises a thermally conductive material, in particular a metal, for thermally conductively connecting the light-absorbing component to the first and / or second surface covered by the condensed water and / or frozen water. The metal is embodied as a foil.

[0014] Preferably, the control unit is configured to control the second laser diode and / or the controllable deflection unit in an inactive operating state of the optical system such that the first light beam and / or the second light beam are directed at the light-absorbing component, each with a maximum laser power. Such an inactive operating state is particularly present in the case of data glasses as an optical system that is arranged within a glasses case. In this case, the eye safety of the data glasses user is not compromised, which is why the maximum laser power can be used to generate the necessary heat energy.

[0015] A further subject matter of the present invention is a method for controlling a control unit of an optical system for a virtual retinal display (retinal scan display). This is, in particular, the optical system described above. The optical system has an illumination device. This is, in particular, a projector unit of the optical system. The illumination device has at least a first laser diode for emitting a first light beam and / or a second laser diode for emitting a second light beam. Alternatively or additionally, the illumination device has a controllable deflection unit as the first optical component for the first light beam for the scanning projection of the image content. The controllable deflection unit has, in particular, at least one micromirror.Furthermore, the optical system has a further optical component for deflecting and / or transmitting the first light beam to a retina of a user of the optical system. In addition, the optical system has a component that absorbs light at least for the first light beam and / or the second light beam. In the method for controlling the control unit, condensation and / or frozen water is first detected on a first surface of the controllable deflection unit and / or on a second surface of the further optical component, in particular in the light path of the first light beam to the user's retina. In a further method step, the second laser diode and / or the controllable deflection unit are controlled by means of the control unit in such a way that the first light beam and / or the second light beam is directed onto the light-absorbing component.Here, the light-absorbing component is thermally conductively connected to the first and / or second surface covered by the captured condensation water and / or frozen water.

[0016] Preferably, control signals detected by a sensor are used to detect the condensation and / or frozen water and forwarded to the control unit. Alternatively or additionally, input signals generated by an input device for the user of the optical system are used to detect the condensation and / or frozen water and forwarded to the control unit. Alternatively, the control unit controls the second laser diode and / or the controllable deflection unit at specific time intervals, in particular during each scan of the image content, such that the first and / or second light beam is directed onto the light-absorbing component. Description of the drawings Fig. 1 shows an embodiment of an optical system for a virtual retinal display (retinal scan display). Fig. 2 shows an embodiment of a further optical component of the optical system, which is thermally conductively connected to a light-absorbing component. Fig. 3 shows a method for controlling a control unit of an optical system for a virtual retinal display (retinal scan display). Description of the embodiments

[0017] The Fig. 1 schematically shows part of an embodiment of an optical system 1 for a virtual retinal display (retinal scan display). The optical system 1, which is designed here as data glasses, has an illumination device 25. The illumination device 25 is designed as a projector unit of the optical system 1. The illumination device 25 has a first laser diode 5 for emitting a first light beam 6 and a second laser diode 23 for emitting a second light beam 24. Furthermore, the optical system 1 has a controllable deflection unit as a first optical component, which has a plurality of, in particular rotatable, micromirrors 7 and 10, which serve for the first light beam 6 for the scanning projection of the image content.Furthermore, the optical system 1 has an exit window 8 as a further optical component for transmitting the first light beam 6 to a retina 2 of a user of the optical system 1. In addition, the optical system has a light-absorbing component 9 for at least the first light beam 6 and the second light beam 24. Furthermore, the optical system comprises a control unit 20 which is designed to control the second laser diode 23 and the controllable deflection unit depending on detected condensation and / or frozen water on a second, outer surface 26 of the exit window 8 as a further optical component, such that the first light beam 6 and the second light beam 24 are directed onto the light-absorbing component 9. The light-absorbing component 9 is thermally conductively connected to the second surface 26 covered by the detected condensation and / or frozen water.In the illustrated embodiment of the optical system 1 as data glasses, all of the aforementioned components are integrated into a temple 4 of the data glasses. Furthermore, the data glasses have at least one lens 14 with an integrated holographic optical element 3 for redirecting the first light beam 6 onto the retina 2 of the user's eye 1.

[0018] In this embodiment, the optical system 1 additionally comprises a sensor 22 for detecting condensation and / or frozen water on the second surface 26. In this context, the sensor 22 is designed to forward the detected sensor signals to the control unit 20. Furthermore, the optical system 1 comprises an input means 21 for the user of the optical system 1 for generating an input signal in the event of condensation and / or frozen water on the second surface 26. The input means, which is designed in particular as a type of key or button, is further designed to forward the input signal to the control unit 20.

[0019] Alternatively, the control unit 20 is designed to control the controllable deflection unit such that the first light beam 6 is directed onto the light-absorbing component 9 at specific time intervals, in particular during each scan of the image content.

[0020] In connection with the control of the controllable deflection device, the micromirror 10 is designed, in a second position, to align or redirect the first light beam 6 in a deflection direction 6b associated with the second position onto the further micromirrors 7 and thus onto the light-absorbing component 9. The second laser diode 23, in turn, is always aligned with the light-absorbing component 9 and is switched on or off by the control unit 20 depending on the detected condensation and / or frozen water on the second, outer surface 26.

[0021] The light-absorbing component 9, which is formed as a black colored layer, is arranged in this embodiment outside the light path 6a of the first light beam 6, on a second edge region of the further optical component 8. The light-absorbing component 9 is designed to absorb light beams of multiple wavelengths. The first light beams 6 have a blue wavelength, and the second light beams 24 have an infrared wavelength. The light-absorbing component 9 absorbs both wavelengths.

[0022] The control unit 20 is configured to control the first laser diode 5 and the second laser diode 23 depending on the detected condensation and / or frozen water on the second surface 26 of the further optical component 8 such that the first light beam 6 and the second light beam 24, when aligned with the light-absorbing component 9, are emitted with an increased laser power, in particular with a power of at least 10 mW. Within the light path 6a or scanning range of the first light beam 6, however, the first light beam 6 is emitted with a lower laser power, in particular with a maximum of 0.4 mW.

[0023] If the data glasses 1 are in an inactive operating state and are not currently being worn by the user, the control unit 20, particularly when the data glasses are in the associated glasses case, is configured to control the second laser diode 23 and the controllable deflection unit such that the first light beam 6 and the second light beam 24 are directed at the light-absorbing component 9, each with a maximum laser power. In this case, there is no risk to the user's eye safety due to the inactive operating state.

[0024] Fig. 2 shows a single lens as a further optical component 13, which is also located in the light path 12 or projection area of the first light beam. The light-absorbing component 19 is arranged outside the light path 12 of the first light beam, on a first edge area of the lens. The light-absorbing component 19 is connected to the second surface covered by the condensation and / or frozen water by means of a heat-conducting material 11, which is formed as a metal, for better spatial distribution of the heat and for the heat-conducting connection of the light-absorbing component 9. Thus, irradiation of the light-absorbing material 9 can lead to the generation of heat in the inner area of the lens 13. Alternatively, various light-absorbing structures, in particular narrow-band structures, are provided within the light path 12 or projection area of the lens and are incorporated into the glass of the lens.These are irradiated by the first light beam and / or the second light beam during the scanning process and thus convert the optical power exactly in the area where it is needed.

[0025] Fig. Figure 3 shows a flowchart of a method for controlling a control unit of an optical system for a virtual retinal display (retinal scan display). The optical system is, in particular, an optical system as shown in Fig. 1 and Fig. 2 is shown and described.

[0026] In a first method step 30, information about condensation and / or frozen water on a first surface of the controllable deflection unit and / or on a second surface of the further optical component, in particular in the light path of the first light beam to the user's retina, is recorded. In a subsequent method step 50, a check is carried out to determine whether the presence of condensation and / or frozen water on the first surface and / or second surface can be inferred from the recorded information. If the control unit determines that condensation and / or frozen water is present, in a subsequent method step 60, the second laser diode and / or the controllable deflection unit is controlled by the control unit such that the first light beam and / or the second light beam is directed onto the light-absorbing component.The light-absorbing component is thermally conductively connected to the first and / or second surface covered by the detected condensation and / or frozen water. The method is then terminated. However, if it is determined in method step 50 that no condensation and / or frozen water is present, the method is terminated or, alternatively, started again.

[0027] Optionally, in method step 30, sensor signals are acquired using a sensor for detecting condensation and / or frozen water, and these sensor signals are forwarded to the control unit in an optional method step 40. Alternatively or additionally, in method step 30, input signals generated by an input means for the user of the optical system are acquired when condensation and / or frozen water is present on the first and / or second surface, and these input signals are forwarded to the control unit in the optional method step 40.

[0028] Optionally, in method step 60, the controllable deflection unit is controlled by means of the control unit such that the first light beam is directed onto the light-absorbing component at specific time intervals, in particular during each scan of the image content.

[0029] Further optionally, the second laser diode is permanently aligned with the light-absorbing component and is switched on by the control unit in method step 55 when condensation and / or frozen water is present. If it is determined that no condensation and / or frozen water is present on the first surface or second surface, the second laser diode is switched off by the control unit in an optional method step 70.

Claims

[1] Optical system (1) for a virtual retinal display (retinal scan display), comprising at least - an illumination device (25), in particular a projector unit, of the optical system (1), wherein the illumination device (25) has at least one first laser diode (5) for emitting a first light beam (6) and / or a second laser diode (23) for emitting a second light beam (24), and / or - a controllable deflection unit as the first optical component, in particular comprising at least one micromirror (7, 10), for the first light beam (6) for scanning projection of the image content, and - a further optical component (8, 13) for deflecting and / or transmitting the first light beam (6) to a retina (2) of a user of the optical system (1), and - a light-absorbing component (9) at least for the first light beam (6) and / or the second light beam (24), and - a control unit (20), wherein the control unit (20) is designed to control the second laser diode (23) and / or the controllable deflection unit depending on detected condensation water and / or frozen water on a first, in particular outer, surface of the controllable deflection unit and / or on a second, in particular outer, surface (26) of the further optical component (8, 13), in particular in the light path (6a) of the first light beam (6) to the retina (2) of the user, in such a way that the first light beam (6) and / or the second light beam (24) is directed onto the light-absorbing component (9), wherein the light-absorbing component (9) is thermally conductively connected to the first and / or second surface (26) covered by the detected condensation water and / or frozen water. [2] Optical system (1) according to claim 1, characterized bythat the further optical component (8, 13) is a lens and / or an exit window, in particular of the first light beam (6) from a spectacle temple (4), and / or a spectacle lens (14). [3] Optical (1) system according to one of claims 1 or 2, characterized by that the optical system (1) is designed as data glasses. [4] Optical system (1) according to one of claims 1 to 3, characterized by that the optical system (1) additionally has a sensor (22) for detecting condensation water and / or frozen water on the first and / or second surface (26), wherein the sensor (22) is designed to forward the sensor signals to the control unit (20). [5] Optical system (1) according to one of claims 1 to 3, characterized bythat the control unit (20) is designed to control the controllable deflection unit in such a way that the first light beam (6) is directed onto the light-absorbing component (9) at certain time intervals, in particular during each scan of the image content. [6] Optical system (1) according to one of claims 1 to 5, characterized by that the second laser diode (23) is permanently aligned with the light-absorbing component (9), and the control unit (20) is designed to switch the second laser diode (23) on or off depending on detected condensation water and / or frozen water on the first surface of the controllable deflection unit and / or on the second surface (26) of the further optical component (8, 13). [7] Optical system (1) according to one of claims 1 to 6, characterized bythat the light-absorbing component (9) is arranged outside the light path (6a) of the first light beam (6), in particular on a first edge region of the controllable deflection unit and / or a second edge region of the further optical component (8, 13). [8] Optical system (1) according to one of claims 1 to 7, characterized by that the light-absorbing component (9) is arranged separately, in particular at a distance, from the controllable deflection unit and / or the further optical component (8, 13). [9] Optical system (1) according to one of claims 1 to 8, characterized by that the light-absorbing component (9) is designed as a light-absorbing layer, in particular as a black color layer. [10] Optical system (1) according to one of claims 1 to 8, characterized bythat the light-absorbing component (9) is designed as a structure incorporated in glass, in particular a narrow-band structure, or as a light-absorbing glass material. [11] Optical system (1) according to one of claims 1 to 10, characterized by that the light-absorbing component (9) absorbs light rays of at least one wavelength, in particular light rays of several wavelengths. [12] Optical system (1) according to one of claims 1 to 11, characterized byin that the control unit (20) is designed to control the first laser diode (5) and / or the second laser diode (23) depending on detected condensation water and / or frozen water on the first surface of the controllable deflection unit and / or on the second surface (26) of the further optical component (8, 13) in such a way that the first (6) and / or second light beam (24) is emitted with an increased laser power, in particular with a power of at least 10 mW, when aligned with the light-absorbing component (9). [13] Optical system (1) according to one of claims 1 to 12, characterized by that the optical system (1) has a heat-conducting material (11), in particular a metal, for the heat-conducting connection of the light-absorbing component (9) to the first and / or second surface (26) covered by the condensation water and / or frozen water. [14] Optical system (1) according to one of claims 1 to 13, characterized by in that the control unit (20) is designed to control the second laser diode (23) and / or the controllable deflection unit in an inactive operating state of the optical system (1), in particular in the case of data glasses as the optical system (1) which is arranged within a spectacle case, in such a way that the first light beam (6) and / or the second light beam (24) is directed onto the light-absorbing component (9) with a maximum laser power in each case. [15] Method for controlling a control unit (20) of an optical system (1) for a virtual retinal display (retinal scan display), with - a lighting device (25), in particular a projector unit, of the optical system (1), wherein the lighting device (25) has at least one first laser diode (5) for emitting a first light beam (6) and / or a second laser diode (23) for emitting a second light beam (24), and / or with - a controllable deflection unit as the first optical component, in particular comprising at least one micromirror (7, 10), for the first light beam (6) for scanning projection of the image content, and - with a further optical component (8, 13) for deflecting and / or transmitting the first light beam (6) to a retina (2) of a user of the optical system (1), and with - a component which absorbs light at least for the first light beam (6) and / or the second light beam (24), the method comprising the following method steps: - detecting (30) condensation and / or frozen water on a first surface of the controllable deflection unit and / or on a second surface (26) of the further optical component (8, 13), in particular in the light path (6a) of the first light beam (6) to the retina (2) of the user, and - controlling (60) the second laser diode (23) and / or the controllable deflection unit by means of the control unit (20) such that the first light beam (6) and / or the second light beam (24) is directed onto the light-absorbing component (9), wherein the light-absorbing component (9) is thermally conductively connected to the first and / or second surface (26) covered by the detected condensation water and / or frozen water.

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