MEMS array system and method of manipulating objects

{
  "publication_number": "US10636936B2",
  "country": "US",
  "kind": "B2",
  "title": "MEMS array system and method of manipulating objects",
  "abstract": "A micro-electro-mechanical systems (MEMS) array system is configured to apply suction forces for the manipulation of objects. The MEMS system includes includes a two-dimensional MEMS array of a plurality of individual MEMS elements. Each MEMS element comprises: a casing structure; a flexible membrane attached to the casing structure; and an electrode structure, wherein a voltage applied to the electrode structure actuates the MEMS element to cause the flexible membrane to flex relative to the casing structure. The flexible membrane and the casing structure define a gap into which the flexible membrane may flex, and a foot extends from the flexible membrane in a direction away from the casing structure, wherein the foot and the flexible membrane define a clearance region on an opposite side of the flexible membrane from the gap. When the MEMS element interacts with an object to be manipulated the foot spaces the membrane apart from the object. The MEMS array system further includes a control circuit that selectively actuates one or more of the MEMS elements of the MEMS array.",
  "claims": [
    "1. A micro-electro-mechanical systems (MEMS) array system comprising: a two-dimensional MEMS array of a plurality of individual MEMS elements arranged in an array of N rows and M columns with N and M being integers greater than or equal to one; each MEMS element comprising: a casing structure; a flexible membrane attached to the casing structure; and an electrode structure, wherein a voltage applied to the electrode structure actuates the MEMS element to cause the flexible membrane to flex relative to the casing structure; wherein the flexible membrane and the casing structure define a gap into which the flexible membrane may flex; and a foot extending from the flexible membrane in a direction away from the casing structure, wherein the foot and the flexible membrane define a clearance region on an opposite side of the flexible membrane from the gap, and when the MEMS element interacts with an object to be manipulated the foot spaces the membrane apart from the object; and a control circuit configured to selectively actuate one or more of the MEMS elements of the MEMS array; wherein the clearance region is open oppositely from the flexible membrane.",
    "2. The MEMS array system of claim 1, wherein the MEMS array has a first resolution of MEMS elements per unit area, and the control circuit is configured to selectively actuate the one or more MEMS elements with the actuated elements having a second resolution different from the first resolution.",
    "3. The MEMS array system of claim 2, wherein the second resolution comprises an individual MEMS element.",
    "4. The MEMS array system of claim 1, wherein: when the voltage comprises a first voltage that is applied to the electrode structure to generate an attractive force between the flexible membrane and a substrate of the casing structure, the flexible membrane is in an on state and flexes in a direction toward the substrate of the casing structure; and when the voltage is not applied to the electrode structure, the flexible membrane is in an off state and the flexible membrane does not flex relative to an initial position.",
    "5. The MEMS array system of claim 4, wherein when the voltage comprises a second voltage that is applied to the electrode structure in a manner that renders the flexible membrane electrically repulsive relative to the substrate of the casing structure, the flexible membrane is in a repel state and flexes in a direction away from the substrate of the casing structure.",
    "6. The MEMS array system of claim 1, wherein: the casing structure comprises a unitary substrate that spans multiple MEMS elements of the MEMS array, and shared casing walls that extend from the unitary substrate and are shared by adjacent MEMS elements of the MEMS array; the electrode structure includes first electrodes that are deposited on the unitary substrate; and the flexible membranes are attached to respective surfaces of the shared casing walls opposite from the unitary substrate.",
    "7. The MEMS array system of claim 1, wherein the control circuit comprises a thin-film transistor (TFT) array.",
    "8. The MEMS array system of claim 1, further comprising: a sensing circuit configured to sense the presence of an object relative to the one or more MEMS elements; and a system controller configured to receive signals from the sensing circuit and apply control signals to the control circuit for control of the voltages applied to the one or more MEMS elements based on the signals received from the sensing circuit.",
    "9. The MEMS array system of claim 8, wherein the sensing circuit comprises a capacitive sensing circuit.",
    "10. The MEMS array system of claim 1, wherein the control circuit comprises a source driver that applies drive signals to voltage source lines for applying voltages to the electrodes of the one or more MEMS elements, and a gate driver that applies gate signals for selection of the one or more MEMS elements to be actuated by applying the voltages from the voltage source lines.",
    "11. The MEMS array system of claim 10, wherein the gate driver is configured to apply the gate signals by row of MEMS elements of the MEMS array.",
    "12. The MEMS array system of claim 1, wherein the casing structure includes a flexible substrate on which the MEMS array is mounted to permit the MEMS array to conform to a non-straight surface of an object to be manipulated.",
    "13. A micro-electro-mechanical systems (MEMS) array system comprising: a two-dimensional MEMS array of a plurality of individual MEMS elements arranged in an array of N rows and M columns with N and M being integers greater than or equal to one; each MEMS element comprising: a casing structure; a flexible membrane attached to the casing structure; and an electrode structure, wherein a voltage applied to the electrode structure actuates the MEMS element to cause the flexible membrane to flex relative to the casing structure; wherein the flexible membrane and the casing structure define a gap into which the flexible membrane may flex; and a foot extending from the flexible membrane in a direction away from the casing structure, wherein the foot and the flexible membrane define a clearance region on an opposite side of the flexible membrane from the gap, and when the MEMS element interacts with an object to be manipulated the foot spaces the membrane apart from the object; and a control circuit configured to selectively actuate one or more of the MEMS elements of the MEMS array; wherein the casing structure includes walls that isolate the gaps of adjacent MEMS elements.",
    "14. A micro-electro-mechanical systems (MEMS) array system comprising: a two-dimensional MEMS array of a plurality of individual MEMS elements arranged in an array of N rows and M columns with N and M being integers greater than or equal to one; each MEMS element comprising: a casing structure; a flexible membrane attached to the casing structure; and an electrode structure, wherein a voltage applied to the electrode structure actuates the MEMS element to cause the flexible membrane to flex relative to the casing structure; wherein the flexible membrane and the casing structure define a gap into which the flexible membrane may flex; and a foot extending from the flexible membrane in a direction away from the casing structure, wherein the foot and the flexible membrane define a clearance region on an opposite side of the flexible membrane from the gap, and when the MEMS element interacts with an object to be manipulated the foot spaces the membrane apart from the object; and a control circuit configured to selectively actuate one or more of the MEMS elements of the MEMS array; wherein at least one foot includes an adhesive material."
  ],
  "description_excerpt": "The present invention relates to an object transfer device comprising an array of micro-electromechanical system (MEMS) elements capable of manipulating objects. Furthermore, the invention relates to a pick-and-place transfer method of moving microscale objects, such as micro light emitting diodes (μLEDs), from a source substrate to a target substrate, and related object transfer methods using a MEMS array.\n\nAn advanced display technology employs the use of micro light-emitting diodes (μLEDs). μLED display technology is expected to outperform OLED and potentially be one of the contenders to replace LCD display technology as the predominant display technology in the next decade. However, the development for mass production of μLED displays has reached a bottleneck due to complications with the mass transfer of μLEDs from a source substrate, such as a growth wafer, to the target display substrate. Transfer yields and efficiency are currently too low for mass production of large displays to be feasible. Large displays, such as tablets or televisions, require millions of μLEDs to be transferred from the source wafer onto the display substrate, and with transfer yields less than 100%, dead pixels are becoming a significant issue in manufacturing a display with the requisite number of μLEDs.\n\nOne of the leading pick and place devices used for transferring μLEDs is an elastomeric stamp, such as the stamp and transfer method described in WO 2016/012409 (Bower et al., published Jan. 28, 2016).",
  "cpc": [
    "B81C 99/002",
    "B25J 15/0085",
    "B25J 7/00",
    "B81B 3/0018",
    "B81B 3/0021",
    "B81B 3/0051",
    "B81B 3/0086",
    "B81B 7/0061",
    "B81C 1/00158",
    "B81C 1/0023",
    "B81C 1/00333",
    "H01L 25/0753",
    "H01L 33/005",
    "H10H 20/01",
    "H10W 72/0198",
    "H10W 72/0711",
    "H10W 72/07178",
    "H10W 72/07183",
    "H10W 90/00"
  ],
  "ipc": [
    "B81B 3/00",
    "B81B 7/00",
    "B81C 1/00",
    "H01L 25/075",
    "H01L 33/00"
  ],
  "assignees": [
    "Sharp Corp"
  ],
  "inventors": [
    "Hywel HOPKIN",
    "Nathan James Smith",
    "Andrew Kay"
  ],
  "filing_date": "2018-03-05",
  "publication_date": "2020-04-28",
  "grant_date": "2020-04-28",
  "priority_date": "2018-03-05",
  "application_number": "US-201815911744-A",
  "family_id": "67767791",
  "cited_by_count": 4,
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    "WO2016012409A2",
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  ]
}