JP2007003209A5

JP2007003209A5 -

Info

Publication number: JP2007003209A5
Application number: JP2005180398A
Authority: JP
Filing date: 2005-06-21
Publication date: 2008-07-10
Anticipated expiration: 2025-06-21

Claims

A sensor head comprising a package in which at least one light source and at least one photodetector are arranged side by side and integrated with a light-transmitting resin, and a scale that is displaced relative to the sensor head, from a light emitting portion of the light source In the optical encoder that reflects and diffracts the emitted light by the scale, receives the reflected and diffracted light by the light receiving unit of the photodetector, and outputs a displacement signal from the sensor head,
Of the light emitted from an arbitrary point of the light emitting part of the light source, the light totally reflected at the interface between the light transmitting resin and the outside is from the light source side than the center of the light receiving part of the photodetector. to be incident on the outside as viewed before Symbol said light emitting portion and the spacing and the refractive index in the thickness and the light transmitting resin of the light transmitting resin and the light receiving portion of the photodetector relationship of the light source is set an optical encoder according to claim and Iruko.

The optical encoder according to claim 1, wherein a surface of the light transmitting resin facing the scale is substantially flat.

The surface of the light transmitting resin facing the scale, the surface of the light emitting part of the light source, and the surface of the light receiving part of the photodetector are substantially parallel,
  The thickness from the surface of the light emitting part of the light source to the surface of the light transmitting resin facing the scale is t11,
  The thickness from the surface of the light receiving portion of the photodetector to the surface of the light transmitting resin facing the scale is t21,
  A distance in a direction parallel to the surface of the light transmitting resin from an arbitrary point of the light emitting portion of the light source to the center of the light receiving portion of the photodetector, dc,
  The refractive index of the outside medium is n1,
When the refractive index of the light transmitting resin is n2, respectively.
  tan ^-1-1 (Dc / (t11 + t21)) <sin ^-1-1 (N1 / n2)
  The optical encoder according to claim 2, wherein the following conditional expression is satisfied.

The surface of the light transmitting resin facing the scale, the surface of the light emitting part of the light source, and the surface of the light receiving part of the photodetector are substantially parallel,
  The thickness from the surface of the light emitting portion of the light source to the surface of the light transmitting resin facing the scale is t111,
  The thickness from the light receiving portion surface of the photodetector to the surface of the light transmitting resin facing the scale is t211;
  The longest distance among the distances in the direction parallel to the surface of the light transmitting resin from an arbitrary point of the light emitting portion of the light source to the light receiving portion of the photodetector is de,
  The refractive index of the outside medium is n1,
  When the refractive index of the light transmitting resin is n2, respectively.
  tan ^-1-1 (De / (t111 + t211)) <sin ^-1-1 (n1 / n2)
  The optical encoder according to claim 2, wherein the following conditional expression is satisfied.

At least a part of the surface between the light emitting part of the light source and the light receiving part of the photodetector among the surfaces of the light transmitting resin facing the scale has a convex part. The optical encoder according to claim 1, wherein

The surface of the convex portion, the surface of the light emitting portion of the light source, and the surface of the light receiving portion of the photodetector are substantially parallel among the surfaces of the light transmitting resin facing the scale,
  The thickness from the surface of the light emitting part of the light source to the surface of the convex part of the light transmitting resin facing the scale is t12,
  The thickness from the surface of the light receiving portion of the photodetector to the surface of the convex portion of the light transmitting resin facing the scale is t22,
  A distance in a direction parallel to the surface of the light transmitting resin from an arbitrary point of the light emitting portion of the light source to the center of the light receiving portion of the photodetector, dc,
  The refractive index of the outside medium is n1,
  When the refractive index of the light transmitting resin is n2, respectively.
  tan ^-1-1 (Dc / (t12 + t22)) <sin ^-1-1 (N1 / n2)
  The optical encoder according to claim 5, wherein the following conditional expression is satisfied.

The surface of the convex portion, the surface of the light emitting portion of the light source, and the surface of the light receiving portion of the photodetector are substantially parallel among the surfaces of the light transmitting resin facing the scale,
  The thickness from the surface of the light emitting part of the light source to the surface of the convex part of the light transmitting resin facing the scale is t122,
  The thickness from the surface of the light receiving portion of the photodetector to the surface of the convex portion of the light transmitting resin facing the scale is t222,
  The longest distance among the distances in the direction parallel to the surface of the light transmitting resin from an arbitrary point of the light emitting portion of the light source to the light receiving portion of the photodetector is de,
  The refractive index of the outside medium is n1,
  When the refractive index of the light transmitting resin is n2, respectively.
  tan ^-1-1 (De / (t122 + t222)) <sin ^-1-1 (N1 / n2)
  The optical encoder according to claim 5, wherein the following conditional expression is satisfied.

A sensor head composed of a package in which at least one light source and at least one photodetector are integrated with a light transmitting resin, and a scale that is displaced relative to the sensor head, and is emitted from a light emitting portion of the light source. In the optical encoder that reflects and diffracts the light with the scale, receives the reflected and diffracted light with the light receiving unit of the photodetector, and outputs a displacement signal from the sensor head,
At least a part of the surface between the light emitting part of the light source and the light receiving part of the photodetector among the surfaces of the light transmitting resin facing the scale has a concave part. An optical encoder.

The surface of the concave portion of the surface of the light transmitting resin facing the scale, the surface of the light emitting portion of the light source, and the surface of the light receiving portion of the photodetector are substantially parallel,
  The thickness from the surface of the light emitting portion of the light source to the surface of the concave portion of the light transmitting resin facing the scale is t13,
  The thickness from the surface of the light receiving portion of the photodetector to the surface of the concave portion of the light transmitting resin facing the scale is t23,
  Ds is the shortest distance among the distances in a direction parallel to the surface of the light transmitting resin from an arbitrary point of the light emitting portion of the light source to the light receiving portion of the photodetector;
  The refractive index of the outside medium is n1,
  When the refractive index of the light transmitting resin is n2, respectively.
  1.73 × (t13 + t23) <ds
  The optical encoder according to claim 8, wherein the following conditional expression is satisfied.

9. The optical encoder according to claim 1, wherein an optical member having at least one slit pattern is disposed on the light source.

The optical encoder according to claim 10, wherein the optical member having the slit pattern is directly attached to the light source.