Diffractive position sensors and control systems
View Patent ↗According to one aspect, systems and methods are provided for detecting the relative position of a transducer head with respect to a storage medium utilizing optically diffractive media. In one example, a head positioning servo system includes a transducer head assembly, a diffractive medium spatially fixed with respect to the transducer head assembly, a light source for illuminating at least a portion of a magnetic storage medium and the diffractive medium, a detector for detecting light from the light source illuminating the magnetic storage medium and the diffractive medium, and a controller for adjusting the position of the transducer head with respect to the magnetic storage medium in response to the detected light.
1. A head positioning servo system, comprising:
a transducer head assembly;
a diffractive medium spatially fixed with respect to the transducer head assembly;
a light source for illuminating an edge of a magnetic storage medium and the diffractive medium;
a detector for detecting light from the light source illuminating the edge of the magnetic storage medium and the diffractive medium; and
a controller for adjusting the position of the transducer head assembly with respect to the magnetic storage medium in response to the detected light, wherein the controller determines the relative position of the transducer head assembly to the magnetic storage medium based on an output pattern of the light illuminating the edge of the magnetic storage medium and passing through the diffractive medium.
2. The system of claim 1 , wherein the magnetic storage medium includes a second diffractive medium.
3. The system of claim 1 , wherein the light source is configured to illuminate the edge of the magnetic storage medium to create a diffraction pattern imaged onto the diffractive medium.
4. The system of claim 1 , wherein the diffractive medium includes a grid of optical marks.
5. The system of claim 1 , wherein the diffractive medium includes a row of optical marks.
6. The system of claim 1 , wherein the diffractive medium is included with a glass tape head island configured to be in contact with a magnetic storage medium.
7. The system of claim 1 , wherein the detector includes a first detector and a second detector displaced laterally across the width of the storage medium.
8. A transducer head assembly, comprising:
a head support structure supporting at least one transducer element;
a diffractive medium spatially fixed with respect to the at least one transducer element;
a light source for illuminating an edge of a magnetic storage medium and the diffractive medium; and
a detector for detecting light from the light source illuminating the edge of the magnetic storage medium and the diffractive medium, wherein the controller determines the relative position of the transducer head assembly to the storage medium based on an output pattern of the light illuminating the edge of the magnetic storage medium and passing through the diffractive medium.
9. The head assembly of claim 8 , further comprising a controller for adjusting the position of the transducer head with respect to the magnetic storage medium in response to the detected light.
10. The head assembly of claim 8 , wherein the magnetic storage medium includes a second diffractive medium.
11. The head assembly of claim 8 , wherein the light source is operable to illuminate the edge of the magnetic storage medium to create a diffraction pattern imaged onto the diffractive medium.
12. The head assembly of claim 8 , wherein the diffractive medium includes a grid of optical marks.
13. The head assembly of claim 8 , wherein the diffractive medium includes a row of optical marks.
14. The head assembly of claim 8 , wherein the diffractive medium is included with a glass tape head island configured to be in contact with a magnetic storage medium.
15. The head assembly of claim 8 , wherein the detector includes a first detector and a second detector displaced laterally across the tape width.
16. A method for detecting the position of a transducer head with respect to a storage medium, comprising:
determining a relative position of a first diffractive medium with respect to an edge of a storage medium;
repositioning the transducer head relative to the storage medium in response to the relative position of the first diffractive medium with respect to the edge of the storage medium; and
determining the relative position of the first diffractive medium and the edge of the storage medium based on an output pattern of light diffracting from the edge of the storage medium and passing through the first diffractive medium.
17. The method of claim 16 , further comprising illuminating the first diffractive medium and the edge of the storage medium with a light source, and detecting light passing both the first diffractive medium and the edge of the storage medium.
18. The method of claim 16 , wherein the first diffractive medium is mechanically coupled with the transducer head.
19. The method of claim 16 , wherein the first diffractive medium includes a grid of optical marks.
20. The method of claim 16 , wherein the first diffractive medium includes a row of optical marks.