Optoelectronic light source and data glasses

Abstract

Provided is an optoelectronic light source that includes a plurality of semiconductor lasers each configured to emit a laser beam and arranged on a mounting platform, and a redirecting optical element configured to redirect the laser beams. The redirecting optical element includes for each one of the plurality of semiconductor lasers a separate reflection zone, the reflection zones are shaped differently from one another, and after passing the redirecting optical element, the laser beams run in a common plane.

Claims

1. An optoelectronic light source comprising: a plurality of semiconductor lasers each configured to emit a laser beam and arranged on a mounting platform, and a redirecting optical element configured to redirect the laser beams, wherein the redirecting optical element comprises for each one of the plurality of semiconductor lasers a separate reflection zone, after passing the redirecting optical element, the laser beams run in a common plane, and beam diameters of the laser beams at the reflection zones amount to at least 1.0 mm so that the redirecting optical element is configured to collimate or focus the laser beams with a remaining divergence angle of at most 2°.

2. The optoelectronic light source according to claim 1, wherein the reflection zones are configured to collimate, focus or to shape the respectively assigned laser beam.

3. The optoelectronic light source according to claim 1, wherein the redirecting optical element is a deflecting optical element that comprises a monolithic mirror block in which all the reflection zones are formed on a single beam shaping side of the redirecting optical element facing the plurality of semiconductor lasers.

4. The optoelectronic light source according to claim 1, wherein the laser beams run in parallel with one other before impinging on the redirecting optical element, wherein the laser beams run in an inclined manner and towards a common crossing point after being reflected at the redirecting optical element, wherein a change in direction of the laser beams at the redirecting optical element is at least 60° and at most 120°.

5. The optoelectronic light source according to claim 1, further comprising a housing, wherein the housing includes a base plate, a housing ring and a cover, and wherein the housing is air-tight.

6. The optoelectronic light source according to claim 1, wherein the plurality of semiconductor lasers is composed of three lasers and includes one laser to emit blue light, one laser to emit green light and one laser to emit red light, wherein said three lasers are arranged next to one another and a plane of mirror symmetry of the redirecting optical element runs through a central one of said three lasers.

7. The optoelectronic light source according to claim 1, wherein each laser in the plurality of semiconductor lasers is an edge emitting laser, emission regions of the lasers are located on a side of said lasers facing the mounting platform, wherein the mounting platform is a submount.

8. Data glasses for virtual or augmented reality applications, comprising an optoelectronic light source according to claim 1, an imaging unit downstream of the optoelectronic light source, and a picture-making element downstream of the imaging unit, wherein the optoelectronic light source is configured to illuminate the picture-making element by means of the imaging unit so that a picture can be produced by means of the picture-making element.

9. The data glasses of claim 8, wherein the imaging unit is a microelectromechanical system, MEMS, mirror, and wherein zero state deflections of the MEMS mirror are different for each one of the laser beams.

10. The data glasses of claim 8, wherein the imaging unit comprises a liquid crystal on silicon, LCoS, element.

11. The data glasses of claim 8, wherein a first optical distance between the plurality of semiconductor lasers and the redirecting optical element is between 0.5 mm and 3 mm inclusive, wherein a second optical distance between the optoelectronic light source and the imaging unit is between 2 mm and 5 cm inclusive, and wherein the picture-making element is one of a screen, a holographic mirror and a two-dimensional waveguide.

12. An optoelectronic light source comprising: a plurality of semiconductor lasers each configured to emit a laser beam and arranged on a mounting platform, a housing, and a redirecting optical element configured to redirect the laser beams, wherein the redirecting optical element comprises for each one of the plurality of semiconductor lasers a separate reflection zone, after passing the redirecting optical element, the laser beams run in a common plane, and the housing includes a base plate, a housing ring, and a cover, and wherein the housing is air-tight.

13. The optoelectronic light source according to claim 12, wherein the redirecting optical element is part of the housing ring which is a metallic ring.

14. The optoelectronic light source according to claim 12, wherein the housing ring comprises an outer ring on a side remote from the plurality of semiconductor lasers and an inner ring facing the plurality of semiconductor lasers, wherein the outer ring and the inner ring are metallic rings, the inner ring is of a softer metal than the outer ring, and wherein the redirecting optical element forms the inner ring.

15. The optoelectronic light source according to claim 12, wherein the cover is transmissive for the laser beams and has a further optical element so that the cover is configured to at least one of: changing a direction of at least one of the laser beams, and combining at least two of the laser beams.

16. The optoelectronic light source according to claim 15, wherein the further optical element comprises an optical grating for at least one of the laser beams or a light guide for at least two of the laser beams.

17. The optoelectronic light source according to claim 15, wherein the further optical element comprises a meta-optical element for at least one of the laser beams.

18. The optoelectronic light source according to claim 15, wherein a common focal point of the laser beams is located between the redirecting optical element and a cover top side of the cover facing away from the plurality of semiconductor lasers.

19. The optoelectronic light source according to claim 15, wherein the laser beams are combined within the cover.

20. The optoelectronic light source according to claim 15, wherein a common focal point of the laser beams is located outside the housing, wherein the laser beams run in the common plane at least between a cover top side of the cover facing away from the plurality of semiconductor lasers and the common focal point.

21. The optoelectronic light source according to claim 12, wherein beam diameters of the laser beams at the reflection zones amount to at least 1.0 mm so that the redirecting optical element is configured to collimate or focus the laser beams with a remaining divergence angle of at most 2°.

22. An optoelectronic light source comprising: a plurality of semiconductor lasers each configured to emit a laser beam and arranged on a mounting platform, and a redirecting optical element configured to redirect the laser beams, wherein the redirecting optical element comprises for each one of the plurality of semiconductor lasers a separate reflection zone, after passing the redirecting optical element, the laser beams run in a common plane each laser in the plurality of semiconductor lasers is an edge emitting laser, emission regions of the lasers are located on a side of said lasers facing the mounting platform, and the mounting platform is a submount.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In the figures:

(2) FIG. 1 is a schematic top view of an exemplary embodiment of an optoelectronic light source described herein,

(3) FIGS. 2 to 4 are schematic sectional views of exemplary embodiments of optoelectronic light sources described herein,

(4) FIG. 5 is a schematic side view of the optoelectronic light source of FIG. 4,

(5) FIG. 6 is a schematic top view of an exemplary embodiment of a redirecting optical element for optoelectronic light sources described herein,

(6) FIG. 7 is a schematic sectional view of an exemplary embodiment of an optoelectronic light source described herein,

(7) FIG. 8 is a schematic sectional view of the cover for the optoelectronic light source of FIG. 7,

(8) FIG. 9 is a schematic top view of the optoelectronic light source of FIG. 7,

(9) FIG. 10 is a schematic sectional view of an exemplary embodiment of an optoelectronic light source described herein,

(10) FIG. 11 is a schematic sectional view of the cover for the optoelectronic light source of FIG. 10,

(11) FIG. 12 is a schematic sectional view of an exemplary embodiment of an optoelectronic light source described herein,

(12) FIGS. 13 and 14 are a schematic sectional views of covers for the optoelectronic light source of FIG. 12,

(13) FIG. 15 is a schematic sectional view of an exemplary embodiment of an optoelectronic light source described herein,

(14) FIG. 16 is a schematic perspective view of the cover for the optoelectronic light source of FIG. 15,

(15) FIG. 17 is a schematic sectional view of an exemplary embodiment of an optoelectronic light source described herein, and

(16) FIGS. 18 and 19 are schematic sectional views of exemplary embodiments of data glasses comprising an optoelectronic light source described herein.

DETAILED DESCRIPTION

(17) FIGS. 1 and 2 illustrate an exemplary embodiment of an optoelectronic light source 1. The optoelectronic light source 1 comprises a plurality of semiconductor layers, for example, three lasers 21, 22, 23 configured to emit red, green and blue laser beams L1, L2, L3, respectively. The lasers 21, 22, 23 are arranged on a common mounting platform 31 which is, for example, a submount.

(18) Further, the optoelectronic light source 1 comprises a redirecting optical element 4 having a beam shaping side 40 facing the lasers 21, 22, 23. The beam shaping side 40 has a first reflection zone 41, a second reflection zone 42 and a first reflection zone 43 to shape, for instance to collimate or to form the laser beams L1, L2, L3. For each one of the laser beams L1, L2, L3, a separate reflection zone 41, 42, 43 is provided.

(19) The laser beams L1, L2, L3 leave the lasers 21, 22, 23 at an edge near the mounting platform 31 and diverge. The lasers 21, 22, 23 can be mounted in parallel with each other on the mounting platform 31. By means of the redirecting optical element 4, the laser beams L1, L2, L3 are shaped, for instance are collimated to become focused laser beams L1, L2, L3 that can meet in one common crossing point. Accordingly, the reflection zone 41, 42, 43 are curved similar to paraboloids.

(20) As an option, the optoelectronic light source 1 further comprises a housing 3. The housing 3 may comprise a base plate 30 on which the mounting platform 31 can be located, and a housing ring 33 around the lasers 21, 22, 23 and the redirecting optical element 4, and a cover 32 atop the lasers 21, 22, 23.

(21) For example, a length D4 of the housing 3 is at least 2 mm and/or is at most 10 mm or at most 5 mm. Alternatively or additionally, a width D3 of the housing 3 is at least 0.9 mm or at least 1.5 mm and/or is at most 8 mm or at most 4 mm.

(22) Moreover, the cover 32 may comprise a further optical element 5 to shape and/or to combine the laser beams L1, L2, L3. The further optical element 5 may be integrated in the cover 5 and may run from an inner side 55 to a cover top side 50. For example, the laser beams L1, L2, L3 have a common focal point at or near the inner side 55, or within the cover 32.

(23) In FIG. 3, it is shown that the redirecting optical element 4 can also shape, in particular to collimate the laser beams L1, L2, L3 to become parallel laser ray bundles. Otherwise, the same as to FIGS. 1 and 2 may also apply to FIG. 3.

(24) In FIGS. 4 and 5, another embodiment of the optoelectronic light source 1 is shown. In this optoelectronic light source 1, the housing ring 3 includes the redirecting optical element 4. Moreover, it is shown that the laser beams L1, L2, L3 are parallel bundles of rays that run in a common plane to an imaging unit 6 which is, for example, a MEMS mirror. The different angles of incidence may electronically be corrected by a color-dependent zero-state of the imaging unit 6.

(25) For example, a first optical distance D1 between the lasers 21, 22, 23 and the beam shaping side 40 of the redirecting optical element 4 is about 1 mm. Alternatively or additionally, a second optical distance D2 between the cover top side 50 and the imaging unit 6, that is, the common crossing point of the laser beams L1, L2, L3, is at least 4 mm or at least 8 mm and/or is at most 5 cm or at most 3 cm. A diameter of the laser beams L1, L2, L3 after passing through the cover 32 is, for example, at least 0.6 mm and/or at most 1.5 mm, for example, 0.9 mm. An angle of divergence of the laser beams L1, L2, L3 outside the housing 3 is, for example, at most 5° or at most 2°. Preferably, the laser beams L1, L2, L3 are of a round and flat top profile. These values could individually or collectively apply to all other exemplary embodiments, too.

(26) Further, according to FIG. 4, the cover 32, the housing ring 33 and the base plate 30 may be connected by means of a connection means 36, like a solder or a metallization. This may particularly be true if the cover 32, the housing ring 33 and the base plate 30 are metallic compounds or comprise at least one metallization configured, for example, for soldering.

(27) Otherwise, the same as to FIGS. 1 to 3 may also apply to FIGS. 4 and 5.

(28) Hence, in the exemplary embodiments described herein the redirecting optical element 4 may be referred to as a deflecting mirror that is designed to tilt the laser beams L1, L2, L3 from the, for example, three RGB lasers 21, 22, 23 to a common point at the imaging unit 6 which is, for example, a MEMS mirror of an AR/VR system. The reflection zones 41, 42, 43 can be designed to shape, for instance to tilt and collimate or focus the incident elliptical laser beams L1, L2, L3 coming from each laser 21, 22, 23. The imaging unit 6 can accommodate for the different inclination angles of the laser beams by means of software, where the MEMS mirror “zero” state deflection is different for each laser color in the image formation process. This may be a bore-sight algorithm used in AR/VR flying spot imaging systems.

(29) The housing 3, also referred to as package, may be based on an AlN substrate for the base plate 30, the housing ring 33 as a deflecting mirror packaging, and the cover 32 as a final output window. The entire package may be hermitically sealed. The optional further optical element 5 may be refractive, diffractive, or meta-optic and can provide additional functionality such as secondary aberration corrections, beam inclination, beam combining and other functions.

(30) In FIG. 6, an exemplary housing ring 3 is illustrated. The housing ring 33 is composed of an inner ring 35 and an outer ring 34. The outer ring 34 may be of rectangular shape and is, for example, of a metal like an FeNiCo alloy and may be plated with AuSn at least in places. The inner ring 35 is, for example, of a metal like Al and may be stamped to shape the reflection zones 41, 42, 43. At the reflection zone 41, 42, 43, the inner ring 35 may be broader than in remaining regions, seen in top view. There can be an axis S of mirror symmetry running through the central reflection zone 42, seen in top view.

(31) FIGS. 7 to 16 show additional embodiments, whereby the titled laser beams L1, L2, L3 from the reflection zones 41, 42, 43 are combined to form a single or near single RGB combined overall beam L. This removes the need for the bore-sight correction, simplifying operation of a VR/AR system and enhancing the field-of-view.

(32) According to FIGS. 7 to 9, the redirecting optical element 4 provides focused spots of the laser beams L1, L2, L3 at input faces of three waveguide structures of a light guide 52 of the further optical element 5. The waveguides then come to a combiner region, providing a single emission region. The waveguide structures are, for example, formed in a low refractive index glass that can be sealed hermetically to the housing ring 33 and/or to the cover 32. Hermetically may mean that a leakage rate is at most 5×10.sup.−8 atm cm.sup.3 s.sup.−1, for example, measured according to the Mil standard MIL-Std 883.

(33) The waveguide structures can be formed by ion-exchange processes, for example. The cover 32 may be applied on top of a portion of the housing ring 33 comprising the light guide 52.

(34) Otherwise, the same as to FIGS. 1 to 6 may also apply to FIGS. 7 to 9.

(35) FIGS. 10 and 11 show an embodiment of an alternative partial beam combining method whereby optical grating 51 are applied as the further optical element 5 on the inner side 55 of the cover 32; the cover top side 50 may be free of any optical grating. Each grating structure is separately optimized to diffract a high fraction of, for example, the red and blue laser beams L1, L3 coming from the redirecting optical element 4. By adjusting the period of the gratings, the deflected beams can be made to diffract in a vertical direction, so that all laser beams L1, L2, L3 are emitted in parallel.

(36) By designing the reflection zones 41, 42, 43 to provide a tightly focused spot near the inner side 55 of the glass cover 32, a distance D5 between adjacent laser beams L1, L2, L3 at the top side 50 can be very small, see FIG. 11, and may be, for example, between 20 μm and 50 μm inclusive, provided that focused spot diameters are on the order of 5 μm to 10 μm inclusive. The grating structures can further be optimized to diffract these focused beams. The result is that emitted diverging beams come from focal spots within some tens of μm of each other.

(37) The reflection zones 41, 42, 43 may also be optimized to have the secondary foci of each laser occur at the approximately same vertical position within or near the cover 32. This provides three beams coming from almost the same position and having identical vertical placement of the secondary source positions, which provide considerable flexibility for the designer of an AR system. Furthermore, having the secondary focus at the cover 32, provides additional flexibility for the external optics placement in an AR system.

(38) Otherwise, the same as to FIGS. 1 to 9 may also apply to FIGS. 10 and 11.

(39) FIGS. 12 to 14 show yet another embodiment based on grating deflector concepts. In this case, the optical gratings 52 are on the inners side 55 and on the top side 50 of the cover 32. The laser beams L1, L2, L3 from the redirecting optical element 4 are adjusted to be incident on the three bottom side gratings at specific angles θR, θG, θB for red, green and blue light, for example. These angles are adjusted such that the individual gratings can deflect each laser beam L1, L2, L3 to the same location on the top side 50 of the cover 32.

(40) Furthermore, these deflected angles inside the cover 32, θR′, θG′, θB′, are such that they are all re-diffracted to the same emission angle in the −1 order of the output grating. For emission of parallel beams, the following condition should be met: sin θ′.sub.j=λ.sub.j/n.sub.sΛ. Here, θ.sub.j′ is the angle of the j=R, G, or B beam within the cover, incident on the top grating, λ.sub.j is the wavelength of the respective beams, and Λ is the period of the top grating; n.sub.s refers to the refractive index of the cover 32.

(41) For the embodiments in FIGS. 10 to 14, the optical gratings 51 can be fabricated by several methods. Possible production methods include DUV lithography and nano-imprint of resist structures followed by etching of the cover 32, or more preferably, a high refractive index coating on either side of the cover 32, not shown. Alternatively, one can use a lift-off procedure with both types of lithography, whereby a coating is applied to a developed resist pattern that is the negative of the desired waveguide patterns. Finally, one can also fabricate highly optimized grating structures by using meta-optic structures.

(42) According to FIG. 13, the grating structure at the top side 50 is located at a center portion, for example, atop the middle grating structure at the inner side 55. Otherwise, see FIG. 14, the grating structure at the top side 50 is located at a border portion, for example, atop the right-most grating structure at the inner side 55. By varying the position of the grating structure at the top side 50, the grating structures can be simplified and all angles θR, θG, θB, θR′, θG′, θB′ may have the same sign, like in FIG. 14.

(43) Otherwise, the same as to FIGS. 1 to 11 may also apply to FIGS. 12 to 14.

(44) FIGS. 15 and 16 show a full application of meta-optic technology to form a chromatic beam combining structure. Here, the structure makes use of meta-optic elements 53 as the further optical element 5 which combines the functions of the three different gratings 51 of FIGS. 13 and 14 in one. For example, the meta-structure may be optimized to diffract the red beam into the −1 order, the green beam into the 0 order and the blue beam into the +1 order, to give a fully overlapping and parallel beam output. The design of the meta-optic elements 53 can be accomplished by optimization schemes including adjoint state topological optimization methods.

(45) Otherwise, the same as to FIGS. 1 to 14 may also apply to FIGS. 15 and 16.

(46) Further, FIG. 17 shows another embodiment that employs the deflecting mirrors and meta-lens technology. Here, the redirecting optical element 4 provides a simpler function of weakly focusing the fast laser axis only so that both fast and slow axes have the same width at the location of the meta-optical element 53 for each laser beam L1, L2, L3. The meta-optical element 53 then uses an astigmatic design to generate circular beams.

(47) The meta-optical element 53 has considerable flexibility to accommodate desired AR/VR optical system design. It could be designed to shape the laser beams, for example, to create three collinear collimated beams, three inclined collimated beams, or three focused beams that merge at a desired intermediate image plane in the scanning AR/VR optical system. Furthermore, each meta-lens can be optimized for each wavelength and field aberrations or astigmatism from each laser 21, 22, 23. Additionally, the meta-lens can provide some beam-forming capability, to convert the more Gaussian fields from the lasers 21, 22, 23 to top-hat profiles, for example. This approach, while not providing direct beam combining, offers considerable flexibility in the transformation of the non-ideal laser beams L1, L2, L3 and can be optimized for each RGB laser 21, 22, 23.

(48) Otherwise, the same as to FIGS. 1 to 16 may also apply to FIG. 17.

(49) In FIGS. 18 and 19, exemplary embodiments of data glasses 10 are illustrated. The data glasses 10 comprise one or a plurality of the optoelectronic light sources 1 as illustrated, for example, in FIGS. 1 to 17. The data glasses 10 may comprise a casing 8 in which the optoelectronic light source 1 is arranged, for example, in temple portions of the data glasses 10. Because of the casing 8, a common housing for the semiconductor lasers 21, 22, 23 and the redirecting optical element 4 may optionally be omitted; however, to hermetically seal the semiconductor lasers 21, 22, 23, preferably there is such a common housing, not shown in FIGS. 18 and 19.

(50) At a front portion of the casing 8, there may be a picture-making element 7, which could be some kind of screen. The imaging unit 6 may be placed at an end or near an end of the respective temple portion.

(51) According to FIG. 18, the imaging unit 6 to project the overall laser beam L to the picture-making element 7 is a microelectromechanical system 61, MEMS, and the picture-making element 7 is a two-dimensional waveguide 71. Optionally, between the imaging unit 6 and the picture-making element 7 there are relay optics 9, for example, to adapt a diameter of the laser beam L. The same applies to all other exemplary embodiments.

(52) However, the imaging unit 6 can also comprise a liquid crystal on silicon 62, LCoS, which may be a miniaturized reflective active-matrix liquid-crystal display using a liquid crystal layer on top of, for example, a silicon backplane, see FIG. 19.

(53) Further, see also FIG. 19, the picture-making element 7 can be a holographic mirror 72, and the relay optics 9 may be placed between the redirecting optical element 4 and the imaging unit 6. As an option, there is an eye tracking unit 63, like a further MEMS, that may be integrated in the imaging unit 6. Such an eye tracking unit 63 can also be present in all other exemplary embodiments.

(54) The invention described here is not restricted by the description on the basis of the exemplary embodiments. Rather, the invention encompasses any new feature and also any combination of features, which includes in particular any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.