Vacuum fixture

{
  "publication_number": "US10170893B1",
  "country": "US",
  "kind": "B1",
  "title": "Vacuum fixture",
  "abstract": "An example method includes stacking a plurality of laser diode bars proximate an alignment plate. Each respective laser diode bar has a front edge through which the respective laser diode bar emits light. The alignment plate has a first side that provides a common plane for aligning the front edges of the laser diode bars and a second side opposite the first side. The alignment plate has a plurality of microholes extending between the first and second sides. The method also includes applying suction to the plurality of laser diode bars through the plurality of microholes. The suction draws the front edges of the laser diode bars against the first side of the alignment plate such that the front edges of the laser diode bars are aligned in the common plane. Conductive plates used to clamp the plurality of laser diodes therebetween may be aligned in a similar fashion.",
  "claims": [
    "1. A method comprising: stacking a plurality of laser diode bars proximate an alignment plate, wherein each respective laser diode bar in the plurality of laser diode bars has a front edge through which the respective laser diode bar is configured to emit light and has an upper surface and a lower surface that are perpendicular to the front edge, wherein the alignment plate has a first side that provides a common plane for aligning the front edges of the laser diode bars and a second side opposite the first side, and wherein the alignment plate has a plurality of microholes extending between the first and second sides; and applying suction to the plurality of laser diode bars through the plurality of microholes, wherein the suction draws the front edges of the laser diode bars against the first side of the alignment plate such that the front edges of the laser diode bars are aligned in the common plane.",
    "2. The method of claim 1, further comprising: while the suction is being applied through the microholes and the front edges of the laser diode bars are aligned in the common plane, clamping the plurality of laser bars together.",
    "3. The method of claim 1, wherein: each respective laser diode bar in the plurality of laser diode bars has a vertical axis that is parallel to the front edge of the respective laser diode bar, and wherein the vertical axis extends through the upper surface and the lower surface of the respective laser diode bar; and stacking the plurality of laser diode bars forms a vertically stacked arrangement in which (i) the vertical axes of the plurality of laser diode bars are parallel and (ii) at least one laser diode bar has an upper surface in contact with a lower surface of an adjacent laser diode bar.",
    "4. The method of claim 3, wherein the upper and lower surfaces of each respective laser diode bar are electrically conductive and provide electrical connections to the respective laser diode bar.",
    "5. The method of claim 4, wherein the laser diode bars are electrically connected together in the vertically stacked arrangement.",
    "6. The method of claim 1, wherein stacking the plurality of laser diode bars proximate the alignment plate comprises sequentially placing the respective laser diode bars proximate the alignment plate while applying suction through the plurality of microholes.",
    "7. The method of claim 1, wherein the plurality of microholes comprise a set of parallel linear arrays of microholes, wherein each linear array of microholes is at an angle with respect to the upper and lower surfaces of the laser diode bars.",
    "8. The method of claim 7, wherein applying suction to the plurality of laser diode bars through the plurality of microholes comprises: applying suction to each respective laser diode bar in the plurality of laser diode bars through a respective set of at least two microholes, the at least two microholes including at least a first microhole in a first linear array of microholes and a second microhole in a second linear array of microholes.",
    "9. The method of claim 1, wherein the alignment plate has a first plurality of macroholes positioned below the plurality of microholes and a second plurality of macroholes positioned above the plurality of microholes, wherein a size of the macroholes is greater than a size of the microholes, and wherein the method further comprises: providing a first conductive substrate on top of which the plurality of the laser diode bars are to be stacked; applying suction to the first conductive substrate through the first plurality of macroholes to draw a front edge of the first conductive substrate against the first side of the alignment plate such that the front edge of the first conductive substrate is aligned in the common plane; providing a second conductive substrate on top of the stacked plurality of laser diode bars; and applying suction to the second conductive substrate through the second plurality of macroholes to draw a front edge of the second conductive substrate against the first side of the alignment plate such that the front edge of the second conductive substrate is aligned in the common plane.",
    "10. The method of claim 9, wherein the first plurality of macroholes comprise a first linear array of macroholes, wherein the second plurality of macroholes comprise a second linear array of macroholes, and wherein the first and second linear arrays of macroholes are parallel to the upper and lower surfaces of the laser diode bars.",
    "11. The method of claim 1, wherein stacking the plurality of laser diode bars proximate the alignment plate comprises causing a robotic die bonder to pick and place each of the plurality of laser diode bars proximate the alignment plate.",
    "12. A non-transitory computer readable storage medium having stored thereon instructions that, when executed by a computing device, cause the computing device to perform operations comprising: providing instructions to cause a robotic device to stack a plurality of laser diode bars proximate an alignment plate, wherein each respective laser diode bar in the plurality of laser diode bars has a front edge through which the respective laser diode bar is configured to emit light and has an upper surface and a lower surface that are perpendicular to the front edge, wherein the alignment plate has a first side that provides a common plane for aligning the front edges of the laser diode bars and a second side opposite the first side, and wherein the alignment plate has a plurality of microholes extending between the first and second sides; and providing instructions to cause a suction device to apply suction to the plurality of laser diode bars through the plurality of microholes, wherein the suction draws the front edges of the laser diode bars against the first side of the alignment plate such that the front edges of the laser diode bars are aligned in the common plane.",
    "13. The non-transitory computer readable storage medium of claim 12, wherein the operations further comprise: providing instructions to cause the robotic device to clamp the plurality of laser diode bars together while the suction is being applied through the microholes and the front edges of the laser diode bars are aligned in the common plane."
  ],
  "description_excerpt": "A laser diode is an electrically pumped semiconductor laser in which the active laser medium is formed by a PN or PIN junction of a semiconductor diode. Several laser diodes may be included on a single semiconductor substrate to form a laser diode bar. The laser diodes may be oriented in the same direction on the substrate to form an edge or facet from which light is emitted. The laser diode bars can be stacked between two conductive substrates, with the emitting edges oriented in the same direction, to form a two-dimensionally emitting surface. The laser diode bar stack may be used for pumping solid state lasers.\n\nIn an example embodiment, a vacuum fixture may be used to align respective light-emitting edges or faces of a plurality of stacked laser diode bars in a common plane. The common plane may be provided by an alignment plate that includes therein a plurality of microholes arranged in a pattern, such as a pattern of linear arrays or a random pattern. As the laser diode bars are stacked proximate the alignment plate, suction may be provided through the microholes to pull the laser diode bars against the alignment plate, thereby aligning their respective light-emitting edges in the common plane. The microholes may be arranged in the pattern (e.g., linear arrays) to ensure that each laser diode bar receives suction through at least one microhole in at least two linear arrays. The aligned laser diode bars may then be clamped together to maintain the alignment.\n\nIn a first embodiment, a method is provided that includes stacking a plurality of laser diode bars proximate an alignment plate.",
  "cpc": [
    "H01S 5/405",
    "H01L 21/68",
    "H01L 21/6838",
    "H01S 5/02365",
    "H10P 72/50",
    "H10P 72/78"
  ],
  "ipc": [
    "H01S 5/40",
    "H10P 72/50"
  ],
  "assignees": [
    "Waymo LLC"
  ],
  "inventors": [
    "Augusto Tazzoli",
    "Pierre-Yves Droz",
    "Nathaniel Golshan"
  ],
  "filing_date": "2017-08-09",
  "publication_date": "2019-01-01",
  "grant_date": "2019-01-01",
  "priority_date": "2017-08-09",
  "application_number": "US-201715672496-A",
  "family_id": "64739855",
  "cited_by_count": 4,
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}