Encoder, printer, and robot

{
  "publication_number": "US10634522B2",
  "country": "US",
  "kind": "B2",
  "title": "Encoder, printer, and robot",
  "abstract": "An encoder includes an optical scale including a scale portion that is constituted with a polarizer, a light emitting portion which emits light, an optical element unit which divides the light into first light and second light and makes the first and second lights incident onto the scale portion, and a light receiving portion which receives the first light and the second light from the scale unit and outputs a signal corresponding to intensities of the received first light and second light, and in which the first light and the second light overlap other within a plane of the scale portion.",
  "claims": [
    "1. An encoder comprising: a light emitting portion that emits light; an optical element unit that divides the light into first light and second light; an optical scale that includes a scale portion constituted with a polarizer, and the scale portion receives the first light and the second light from the optical element unit; and a light receiving portion that receives the first light and the second light from the scale portion and outputs a signal corresponding to light intensities of the received first and second lights, wherein the first light and the second light overlap on a face of the scale portion.",
    "2. The encoder according to claim 1, wherein, when an incident angle of the first light with respect to the scale portion is set as θ 1 and an incident angle of the second light with respect to the scale portion is set as θ 2, a relationship of θ 1 ≠θ 2 is satisfied.",
    "3. The encoder according to claim 1, wherein, when an angle formed between an incident direction of the first light and the incident direction of the second light to the scale portion is set as θ 3 in plan view when seen from a normal direction of the scale portion, the relationship of θ 3 <180° is satisfied.",
    "4. The encoder according to claim 1, wherein the light receiving portion includes first light receiving element that receives the first light and second light receiving element that receives the second light.",
    "5. The encoder according to claim 4, wherein the first light receiving element and the second light receiving element locates at a side opposite to the light emitting portion with respect to a virtual line segment that passes through the center of a portion where the first light and the second light overlap in the plane of the scale portion perpendicular to a virtual line segment connecting the center of the overlapping portion and the center of the light emitting portion, in plan view when seen from the normal direction of the scale portion.",
    "6. The encoder according to claim 5, wherein the light emitting portion, the first light receiving element, and the second light receiving element are on the same straight line in plan view.",
    "7. The encoder according to claim 4, wherein the light emitting portion, the first light receiving element, and the second light receiving element are on the same straight line when seen from a direction in which the scale portion expands.",
    "8. The encoder according to claim 4, wherein the light emitting portion, the first light receiving element, and the second light receiving element are disposed on the same substrate.",
    "9. The encoder according to claim 1, wherein the optical scale includes a reflective plate disposed at a side opposite to the light emitting portion with respect to the scale portion.",
    "10. The encoder according to claim 1, wherein the optical scale is provided along a circumferential direction around the center axis of the optical scale and has an identification pattern different every 90° or 180° in the circumferential direction.",
    "11. The encoder according to claim 1, wherein the optical element unit includes a beam splitter that divides the light into the first light and the second light, a reflective member that reflects first light from the beam splitter toward the scale portion, and a phase difference plate disposed on an optical path of the second light from the beam splitter to the scale portion.",
    "12. An encoder comprising: a light emitting portion that emits light; an optical element unit that divides the light into first light and second light; an optical scale that includes a scale portion constituted with a phase difference plate, and the scale portion receives the first light and the second light from the optical element unit; and a light receiving portion that receives the first light and the second light from the scale portion and outputs a signal corresponding to light intensities of the received first and second lights, wherein the first light and the second light overlap on a face of the scale portion.",
    "13. A printer comprising: the encoder according to claim 1.",
    "14. A printer comprising: the encoder according to claim 2.",
    "15. A printer comprising: the encoder according to claim 3.",
    "16. A printer comprising: the encoder according to claim 4.",
    "17. A robot comprising: the encoder according to claim 1.",
    "18. A robot comprising: the encoder according to claim 2.",
    "19. A robot comprising: the encoder according to claim 3.",
    "20. A robot comprising: the encoder according to claim 4."
  ],
  "description_excerpt": "1. Technical Field The present invention relates to an encoder, a printer, and a robot. 2. Related Art As one type of encoder, an optical rotary encoder is generally known (see, for example, JP-A-2008-241453). For example, the rotary encoder is used for a robot provided with a robot arm having a rotatable joint part, and detects a rotation state such as a rotation angle, a rotation position, the number of rotations, and a rotation speed of the joint part. For example, the optical encoder disclosed in JP-A-2008-241453 includes a rotation polarizing plate attached to a rotation shaft, a first fixed polarizing plate provided so as to face the rotation polarizing plate, a second fixed polarizing plate provided on the same plane as the first fixed polarizing plate so as to face the rotation polarizing plate and has a polarization plane different by 45 degrees with respect to a polarization plane of the first fixed polarizing plate, a light source for allowing the rotation polarizing plate to be irradiated with light, first light receiving element for receiving light which is from the light source and has passed through the rotation polarizing plate and the first fixed polarizing plate and generating a first electric signal corresponding to the light, and second light receiving element for receiving light which is from the light source and has passed through the rotation polarizing plate and the second fixed polarizing plate and generating a second electric signal corresponding to the light.",
  "cpc": [
    "G01D 5/345",
    "B25J 19/0095",
    "B25J 9/0009",
    "B25J 9/1697",
    "B41J 2/2103",
    "B41J 3/4075",
    "G01D 5/347",
    "G01D 5/34707",
    "G01D 5/34776",
    "G02B 27/126",
    "Y10S 901/31",
    "Y10S 901/47"
  ],
  "ipc": [
    "B25J 9/16",
    "B41J 2/21",
    "B41J 3/407",
    "G01D 5/34",
    "G01D 5/347",
    "G02B 27/12"
  ],
  "assignees": [
    "SEIKO EPSON CORP"
  ],
  "inventors": [
    "WADA HIROSHI"
  ],
  "filing_date": "2018-04-20",
  "publication_date": "2020-04-28",
  "grant_date": "2020-04-28",
  "priority_date": "2017-04-25",
  "application_number": "US-201815958235-A",
  "family_id": "62062925",
  "citations": [
    "EP1674834A2",
    "JP2006322835A",
    "JP2008241453A",
    "JPH06194189A",
    "JPH0781883B2",
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    "US2003155489A1",
    "US2008186491A1",
    "US2013128255A1",
    "US2014311258A1",
    "US2014360804A1",
    "US2015292870A1",
    "US2016116757A1",
    "US2018170423A1",
    "US2018306605A1",
    "US2019101418A1",
    "US3584959A",
    "US4967072A",
    "US5424535A",
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    "US6038523A",
    "US7476844B2",
    "US8297727B2"
  ]
}