PATENT DOCUMENT

Publication Number: US-12218478-B2
Application Number: US-202117233489-A
Country: US
Kind Code: B2

Title: Folded optical conjugate lens

Abstract:
An optoelectronic device includes a semiconductor substrate having first and second faces. An emitter is disposed on the first face of the semiconductor substrate and is configured to emit a beam of radiation through the substrate. At least one curved optical surface is formed in the second face of the semiconductor substrate. A first reflector is disposed on the first face in proximity to the emitter, and a second reflector is disposed on the second face in proximity to the curved optical surface, such that the second reflector reflects the beam that was emitted through the semiconductor substrate by the emitter to reflect back through the semiconductor substrate toward the first reflector, which then reflects the beam to pass through the semiconductor substrate so as to exit from the semiconductor substrate through the curved optical surface.

Claims:
The invention claimed is: 
     
       1. An optoelectronic device, comprising:
 a semiconductor substrate having first and second faces; 
 an emitter, which comprises a mesa, having sidewalls, disposed on the first face of the semiconductor substrate and is configured to emit a beam of radiation through the substrate; 
 at least one curved optical surface, which is formed in the second face of the semiconductor substrate; and 
 a first reflector, having a reflectance exceeding 94%, extending across the first face beyond the sidewalls of the mesa in proximity to the emitter and a second reflector, which is planar and is disposed on the second face in proximity to the curved optical surface, such that the second reflector reflects the beam that was emitted through the semiconductor substrate by the emitter to reflect back through the semiconductor substrate toward the first reflector, which then reflects the beam to pass through the semiconductor substrate so as to exit from the semiconductor substrate through the curved optical surface. 
 
     
     
       2. The optoelectronic device according to  claim 1 , wherein the at least one curved optical surface comprises a spherical surface. 
     
     
       3. The optoelectronic device according to  claim 1 , wherein the semiconductor substrate comprises a III-V semiconductor compound. 
     
     
       4. The optoelectronic device according to  claim 3 , wherein the III-V semiconductor compound comprises gallium (Ga) and arsenic (As). 
     
     
       5. The optoelectronic device according to  claim 1 , wherein the emitter comprises a vertical-cavity surface-emitting laser (VCSEL). 
     
     
       6. The optoelectronic device according to  claim 5 , wherein the VCSEL comprises a lower distributed Bragg reflector (DBR) disposed on the first face of the substrate, and wherein the lower DBR extends across the first face beyond the sidewalls of the mesa so as to define the first reflector. 
     
     
       7. The optoelectronic device according to  claim 1 , wherein the first reflector comprises a metal layer disposed on the first face of the substrate. 
     
     
       8. The optoelectronic device according to  claim 1 , wherein the second reflector is disposed at an apex of the curved optical surface. 
     
     
       9. The optoelectronic device according to  claim 1 , wherein the second reflector is tilted relative to a normal to the substrate. 
     
     
       10. The optoelectronic device according to  claim 9 , wherein the curved optical surface is offset on the second face of the semiconductor substrate relative to the emitter. 
     
     
       11. The optoelectronic device according to  claim 10 , wherein an offset of the curved optical surface relative to the emitter is selected so that the beam exiting from the semiconductor substrate through the curved optical surface is perpendicular to the semiconductor substrate. 
     
     
       12. An assembly comprising at least first and second optoelectronic devices, each of the optoelectronic devices comprising:
 a semiconductor substrate having first and second faces; 
 an emitter, comprising a mesa having sidewalls, which is disposed on the first face of the semiconductor substrate and is configured to emit a beam of radiation through the substrate; 
 at least one curved optical surface, which is formed in the second face of the semiconductor substrate; and 
 a first reflector extending across the first face beyond the sidewalls of the mesa in proximity to the emitter and a second reflector disposed on the second face in proximity to the curved optical surface, such that the second reflector reflects the beam that was emitted through the semiconductor substrate by the emitter to reflect back through the semiconductor substrate toward the first reflector, which then reflects the beam to pass through the semiconductor substrate so as to exit from the semiconductor substrate through the curved optical surface, 
 wherein the second reflector is tilted relative to a normal to the substrate, 
 wherein the curved optical surface is offset on the second face of the semiconductor substrate relative to the emitter by an offset selected so that the beam exiting from the semiconductor substrate through the curved optical surface is perpendicular to the semiconductor substrate, and 
 wherein the at least first and second optoelectronic devices are spaced apart on the substrate by a given device spacing, and the at least first and second devices have respective first and second offsets of the curved optical surface relative to the emitter in different first and second directions, which are selected so that the respective first and second beams exiting through the respective curved optical surfaces are spaced apart by a pitch that is smaller than the device spacing. 
 
     
     
       13. The optoelectronic device according to  claim 1 , wherein the at least one curved optical surface is shaped so as to focus the beam to a waist at a specified distance from the semiconductor substrate. 
     
     
       14. The optoelectronic device according to  claim 13 , wherein the semiconductor substrate is mounted behind a panel containing a transparent window, such that the waist of the beam is located within the transparent window. 
     
     
       15. The optoelectronic device according to  claim 1 , wherein the second reflector is disposed on the curved optical surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application 63/022,501, filed May 10, 2020, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to optoelectronic devices, and particularly to beam-forming optics for optical emitters. 
     BACKGROUND 
     Semiconductor lasers, such as vertical-cavity semiconductor lasers (VCSELs), are used for illumination tasks especially in portable devices, where compact light sources are required. (The terms “optical rays,” “optical radiation,” and “light,” as used in the present description and in the claims, refer generally to any and all of visible, infrared, and ultraviolet radiation.) VCSELs may be produced in front-emitting and back-emitting configurations. In the back-emitting configuration, the VCSEL is fabricated on a first face of a semiconductor substrate, and emits optical radiation through the substrate toward and through its second face. 
     VCSELs and other sorts of solid-state light emitters are commonly integrated with a small lens (referred to as a microlens) that directs and collimates the emitted beam. An array of such microlenses may be fabricated integrally over a semiconductor substrate on which an array of emitters is formed, with the microlenses in alignment with the emitters. 
     SUMMARY 
     Embodiments of the present invention that are described hereinbelow provide improved designs and methods for controlling the output beam from a solid-state radiation source. 
     There is therefore provided, in accordance with an embodiment of the invention, an optoelectronic device, including a semiconductor substrate having first and second faces and an emitter, which is disposed on the first face of the semiconductor substrate and is configured to emit a beam of radiation through the substrate. At least one curved optical surface is formed in the second face of the semiconductor substrate. A first reflector is disposed on the first face in proximity to the emitter, and a second reflector is disposed on the second face in proximity to the curved optical surface, such that the second reflector reflects the beam that was emitted through the semiconductor substrate by the emitter to reflect back through the semiconductor substrate toward the first reflector, which then reflects the beam to pass through the semiconductor substrate so as to exit from the semiconductor substrate through the curved optical surface. 
     In a disclosed embodiment, the at least one curved optical surface includes a spherical surface. 
     In some embodiments, the semiconductor substrate includes a III-V semiconductor compound. In a disclosed embodiment, the III-V semiconductor compound includes gallium (Ga) and arsenic (As). 
     Additionally or alternatively, the emitter includes a vertical-cavity surface-emitting laser (VCSEL). In a disclosed embodiment, the VCSEL includes a mesa having sidewalls and a lower distributed Bragg reflector (DBR) disposed on the first face of the substrate, and the lower DBR extends across the first face beyond the sidewalls of the mesa so as to define the first reflector. 
     Alternatively, the first reflector includes a metal layer disposed on the first face of the substrate. 
     In some embodiments, the second reflector is disposed at an apex of the curved optical surface. The second reflector may be planar or curved. 
     Alternatively, the second reflector is tilted relative to a normal to the substrate. In some embodiments, the curved optical surface is offset on the second face of the semiconductor substrate relative to the emitter. In a disclosed embodiment, an offset of the curved optical surface relative to the emitter is selected so that the beam exiting from the semiconductor substrate through the curved optical surface is perpendicular to the semiconductor substrate. Additionally or alternatively, the at least first and second optoelectronic devices are spaced apart on the substrate by a given device spacing, and the at least first and second devices have respective first and second offsets of the curved optical surface relative to the emitter in different first and second directions, which are selected so that the respective first and second beams exiting through the respective curved optical surfaces are spaced apart by a pitch that is smaller than the device spacing. 
     In some embodiments, the at least one curved optical surface is shaped so as to focus the beam to a waist at a specified distance from the semiconductor substrate. In one such embodiment, the semiconductor substrate is mounted behind a panel containing a transparent window, such that the waist of the beam is located within the transparent window. 
     There is also provided, in accordance with an embodiment of the invention, an optoelectronic assembly, which includes a display, including a display substrate, which is transparent to optical radiation at a given wavelength, and an array of display cells including pixel circuit elements disposed on the display substrate with one or more gaps defining transparent windows between the pixel circuit elements. An emitter device includes a semiconductor substrate having first and second faces and one or more emitters, which are disposed on the first face of the semiconductor substrate and are configured to emit respective beams of optical radiation through the substrate. One or more curved optical surfaces are formed in the second face of the semiconductor substrate and are configured to focus the one or more beams emitted from the emitters to respective waists that are aligned in respective ones of the transparent windows. 
     In a disclosed embodiment, the emitter device includes multiple reflectors associated with each of the one or more emitters, so that the one or more beams are reflected within the semiconductor substrate multiple times before exiting through the curved optical surfaces. 
     Methods for producing and operating optoelectronic devices and assemblies are also provided. 
     The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic sectional view of an optoelectronic device, in accordance with an embodiment of the present invention; 
         FIG.  2    is a schematic sectional view of an optoelectronic device, in accordance with another embodiment of the present invention; and 
         FIG.  3    is a schematic sectional view of an optoelectronic assembly, in accordance with a further embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Semiconductor lasers, such as vertical-cavity semiconductor lasers (VCSELs), can be used for illumination tasks especially in portable devices, in which compact light sources are required. Some applications require that the waist of the Gaussian beam emitted by a VCSEL be located at a specific distance from the VCSEL in order to match the locations of the other components of the device. For example, the application may require that the beam be focused so as to pass through a small aperture, such as an aperture between the pixels of a display. In back-emitting VCSELs, which are formed on a first face of a semiconductor substrate, the focal distance of the Gaussian beam (i.e., the distance to the waist of the beam) exiting through the second face of the substrate may be controlled for this purpose by a microlens formed on the second face. Due to size and process constraints, however, the focal distances of such microlenses may be too short to match the locations of the other components. 
     The embodiments of the present invention that are described herein address these problems by providing a compact optoelectronic device in which the beam emitted by a solid-state emitter through a semiconductor substrate, such as a back-emitting VCSEL, is reflected multiple times through the substrate and focused, so that the Gaussian waist of the beam is formed at a large distance from the substrate, relative to solutions that are known in the art. 
     In the disclosed embodiments, a microlens is formed on the semiconductor substrate opposite the emitter. Two reflectors are formed on the two faces of the substrate: a first reflector formed on the first face near the emitter, and a second reflector disposed on the second face on or near the curved optical surface of the microlens. The emitter emits a beam of optical radiation through the substrate toward the second reflector, which reflects the beam back through the substrate onto the first reflector. The first reflector further reflects the beam toward the curved optical surface, which refracts the beam and transmits it out of the substrate. 
     In the disclosed embodiments, the first reflector is planar, whereas the second reflector may be either concave, planar, or convex. A planar second reflector increases the effective optical thickness of the substrate (by causing the beam to pass through the substrate multiple times before exiting through the curved optical surface), and in this way increases the distance of the beam waist from the substrate. When employing a curved second reflector, the radii of curvature of the second reflector and the curved optical surface are chosen so that reflectors and the curved optical surface together form a telescope, which projects the beam waist of the emitted beam to the required distance. 
     In some embodiments, the second reflector is tilted so that the reflected beam is shifted laterally. This shift prevents the second reflector from obscuring the beam as it exits through the curved optical surface. An offset of the curved optical surface may be used to compensate for the tilt introduced by the second reflector. The direction of the lateral offset in the plane of the substrate may be controlled by the direction of the tilt and the respective offsets of the second reflector and the curved optical surface. By appropriate selection of the sizes and directions of these lateral offsets, a group of two or more (possibly up to six) emitters may be formed with the lateral distances between the emitted rays smaller than the distance between the respective VCSELs. 
       FIG.  1    is a schematic sectional view of an optoelectronic device  20 , in accordance with an embodiment of the present invention. 
     Optoelectronic device  20  is formed on a semiconductor substrate  22 . Typically, substrate  22  comprises a wafer of a III-V semiconductor compound, such as gallium-arsenide (GaAs), which is transparent to near-infrared radiation. A VCSEL  24  is formed on a first face  25  of substrate  22  using semiconductor fabrication methods and processes that are known in the art. A laser cavity for VCSEL  24  is formed by epitaxial deposition of thin-film layers to produce a lower distributed Bragg-grating (DBR)  28  and an upper DBR  30 , wherein the DBRs comprise highly reflective multilayer mirrors. A multiple-quantum-well (MQW) stack  32 , comprising a series of quantum wells disposed between a series of barriers, is deposited over lower DBR  28 , and upper DBR  30  is deposited over the MQW stack. For example, MQW stack  32  may comprise alternating InAlGaAs quantum wells and InAlGaAs barriers. VCSEL  24  is etched to form a mesa-structure with sidewalls  26 , and an oxide aperture is formed to define the optical and electrical current aperture of the VCSEL. 
     For the sake of simplicity, additional layers of VCSEL  24 , such as electrical conductors, have been omitted from the figure. 
     A curved optical surface  36  has been formed on a second face  38  of substrate  22 , forming a microlens  40  with a focal length of f. Such curved optical surfaces can be formed on substrate  22  by methods known in the art, such as gray-scale photolithography or the Confined Etchant Layer Technique (CELT). In the present embodiment, curved optical surface  36  is a spherical surface with a radius of curvature of R 1 . Alternatively, curved optical surface  36  may be an aspheric surface, such as, for example, a parabola, or may have any other suitable form. 
     Optical device  20  also comprises a second reflector deposited on second face  38  in proximity to curved optical surface  36 . In the pictured embodiment, second reflector  42  is formed over an apex  44  of microlens  40 . The area for second reflector  42  is formed in the same processing steps as curved optical surface  36 . Alternatively, additional patterning and etch steps, such as those, for example, described with reference to  FIG.  2   , may be used to flatten apex  44 . Second reflector  42  may be either flat or have a concave or convex shape toward VCSEL  24 . 
     After etching of curved optical surface  36  and apex  44 , second face  38  is passivated, and an anti-reflective coating  46 , for example, comprising a quarter-wave layer of silicon-nitride (SiN) is deposited on curved optical surface  36 . Second reflector  42  is formed on apex  44  by coating the apex with gold, which provides a reflectance of 97% for near-infrared radiation emitted by VCSEL  24  (for example at 940 nm), or with another suitable metal or multi-layer thin film coating. 
     Lower DBR  28  and a metallic redistribution layer (RDL) (a metal layer between electrodes of VCSEL  24  and substrate  22 ) together form a first reflector  50  on first face  25 . At the near-IR wavelength of VCSEL  24 , the reflectance of lower DBR  28  is typically 99%, and the reflectance of RDL  48  exceeds 94%. In an alternative embodiment (not shown in the figures), some of the epitaxial layers of lower DBR  28  are not etched away in forming the mesa structure of VCSEL  24 , and thus extend across face  25  of substrate  22  beyond sidewalls  26  and define the entire area of reflector  50 . In this case, reflector  50  may have higher overall reflectance, without gaps at the boundary between lower DBR  28  and RDL  48 . 
     VCSEL  24  emits a diverging beam  52  of optical radiation, which is reflected by second reflector  42  toward first reflector  50  as a beam  54 . First reflector  50  reflects beam  54  into a beam  56 , which propagates toward second face  38 . When second reflector  42  is planar (infinite radius of curvature), beam  54  continues diverging with the same divergence as beam  52 . Due to the planar form of first reflector  50 , this divergence is preserved in beam  56 , too, thus causing the outer part of beam  56  to impinge on curved optical surface  36  outside second reflector  42 . This part of beam  56  is refracted by curved optical surface  36  into a beam  58 , having a waist  60  located a distance z out  above apex  44 . Due to the back-and-forth reflections between first and second reflectors  50  and  42 , respectively, the optical path for the beam emitted by VCSEL  24  and exiting through curved optical surface  36  is effectively tripled, as compared to a beam exiting without these reflections. 
     Assuming beam  52  to be Gaussian, the distance z out  is given by: 
                     1     z   out       =       1   f     -     1       t   eff     +       z   r   2     /     (       t   eff     -   f     )                     (   1   )               
wherein the parameters of the equation are:
         f=the focal length of microlens  40 .   t eff =the optical thickness of substrate  22 , t sub , multiplied by the number of passes of the beam through the substrate in the multi-pass geometry.   z r =the Rayleigh range of VCSEL  24 .       

     This equation illustrates that for a given focal length f, the multi-pass geometry of device  20  can be used to position waist  60  at a substantially greater distance from second face  38  than would be possible in a conventional, single-pass geometry. Typical values for these parameters are t sub =100-200 μm, f=50-100 μm, and z r =50 μm, although other parameter values may alternatively be used. 
     In alternative embodiments, second reflector  42  is formed with a curved optical surface. Forming second reflector  42  with a convex shape towards VCSEL  24  provides for additional optical power for the optics of optoelectronic device  20  and requires a larger diameter for microlens  40 , as compared to a planar shape of the second reflector. Conversely, forming second reflector  42  with a concave shape towards VCSEL  24  reduces the optical power and the required diameter for microlens  40 . 
     Increasing the distance z out  to beam waist  60  in device  20  is particularly useful when device  20  is to be mounted behind a panel  62 , such as a circuit substrate, and is required to emit beam  58  through a transparent window  64  in the panel. By proper choice of the thickness of substrate  22  and the parameters of optical surface  36 , it is possible to achieve values of z out  in the range of 300-500 μm, which is sufficient to enable mounting substrate  22  behind panel  62  so that waist  60  is aligned within window  64  with reasonable design tolerances. When aligned in this manner, beam  58  will pass through panel  62  with only minimal scatter and loss. 
     For example, electronic display layouts can be designed with a transparent window in a gap between the pixel circuit elements within each pixel of the display. Such a display typically comprises a substrate, such as glass, which is transparent to optical radiation at wavelengths in the visible and near infrared ranges. An array of display cells is formed on the substrate by methods of display fabrication that are known in the art. Each display cell comprises pixel circuit elements  66 , such as an OLED (organic light-emitting diode) and a TFT (thin-film transistor) for switching the OLED, as well as conductors connecting the pixel circuits to electronics external to the display. 
     The display cells are spaced on the substrate (for example, on panel  62  in the example shown in  FIG.  1   ) at a certain pixel pitch, with gaps of a predefined size, defining one or more transparent windows  64 , between the pixel circuit elements. One or more VCSELs  24  are placed behind respective windows  64  and are aligned so that each beam  58  passes through the corresponding window. Specifically, device  20  is designed, based on the principles explained above, and aligned with the display so that the beam waist  60  of each device falls within window  64 . 
     A single VCSEL  24  or an array of VCSELs behind an array of windows  64  in a display panel can thus provide illumination for applications of a mobile computing device, such as a smartphone or tablet computer. In this manner, the area of the display can be maximized, relative to the size of the computing device, without requiring that panel space be allocated for the illumination source. For example, the VCSELs can illuminate the area in front of the display for applications such as  3 D mapping or face recognition. 
       FIG.  2    is a schematic sectional view of an optoelectronic device  100 , in accordance with another embodiment of the present invention. 
     Optoelectronic device  100  comprises, similarly to optoelectronic device  20 , VCSEL  24  on first face  25  of substrate  22  and microlens  40  on second face  38 . A planar second reflector  102 , having a normal  103  to its surface, is tilted with respect to a normal  105  of substrate  22  (i.e., normal  103  is not parallel to normal  105  of substrate  22 ). As in the embodiment of  FIG.  1   , the tilted area is coated with gold or other suitable materials for high reflectance. Alternatively, second reflector  102  may have a curved shape. 
     Beam  104  emitted by VCSEL  24  impinges on second reflector  102 , which reflects it as a beam  106  toward first reflector  50 . As second reflector  102  is tilted, beam  106  impinges on first reflector  50  at a non-normal angle and with a lateral offset from VCSEL  24 . Consequently, with a suitable tilt angle of second reflector  102 , a beam  108  reflected from first reflector  50  impinges on curved optical surface  36  of microlens  40  avoiding second reflector  102 , thus reducing multiple reflections and increasing the output coupling efficiency. Beam  108  is refracted by microlens  40  and exits as a beam  110 . In the embodiment shown in  FIG.  2   , beam  110  exits from microlens  40  at a non-zero exit angle α with respect to normal  105  of substrate  22 . In an alternative embodiment, beam  110  is directed along a normal to substrate  22  (i.e., exit angle α is brought to zero) by a suitable lateral offset of microlens  40  relative to VCSEL  24 , as shown in  FIG.  3   , below. 
       FIG.  3    is a schematic sectional view of an optoelectronic assembly  150  comprising a pair of optoelectronic devices  200  and  202 , in accordance with an additional embodiment of the present invention. Optoelectronic devices  200  and  202 , formed on a substrate  203 , are similar to optoelectronic device  100 . Optoelectronic device  200  comprises a VCSEL  204 , a microlens  206 , and a tilted second reflector  208 , corresponding respectively to VCSEL  24 , microlens  40 , and second reflector  102  of optoelectronic device  100 . Microlens  206  is positioned with an offset  210  between its optical axis  212  and an optical axis  214  of VCSEL  204 . Offset  210  has been selected so that a beam  216 , exiting from microlens  206 , is perpendicular to substrate  203 , with an offset of  218  from optical axis  214  of VCSEL  204 . Additional labels, such as in  FIG.  2   , have been omitted for the sake of clarity. 
     Optoelectronic device  202  comprises a VCSEL  220 , a microlens  222 , and a tilted second reflector  224 . Optoelectronic device  202  is identical to optoelectronic device  200 , except that it is oriented with a 180° rotation around a normal to substrate  203  by comparison with device  200 . Thus, a beam  226  emitted by optoelectronic device  202  is perpendicular to substrate  203  with an offset  228  to an optical axis  230  of VCSEL  220 , equal and opposite to offset  218  of device  200 . 
     Due to the relative orientations of optoelectronic devices  200  and  202 , a spacing (or pitch)  232  between beams  216  and  226  is substantially smaller than a spacing  234  between optical axes  214  and  228  of VCSELs  204  and  220 . Thus, beams  216  and  226  may pass together through a relatively narrow aperture (not shown) above device  150  and create a dense pattern of beams or a combined beam of high intensity in the far field. 
     In alternative embodiments, a larger number of optoelectronic devices, similar to devices  200  and  202 , may be arranged in close proximity to each other and with suitable rotations around normals to the substrate, thus achieving beam-to-beam pitches that are smaller than the corresponding VCSEL-to-VCSEL pitches. A reduction of beam-to-beam pitches may be achieved with up to six devices. 
     It will be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.

Metadata:
Filing Date: 20210418
Publication Date: 20250204
Grant Date: 20250204
Priority Date: 20200510
Inventors: LYON, Keith
Assignee: APPLE INC
CPC Classifications: [{"code": "H01S5/423", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/34313", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/18344", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/8067", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/806", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B19/0052", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/02255", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/0286", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/423", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/04254", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/18375", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/18377", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/18347", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/18305", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/04253", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/0207", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01S5/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/0225", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01S5/0267", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01S5/423", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/34313", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/18344", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01S5/0225", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 75888189