Speckle navigation system
First Claim
1. A method of sensing relative movement between a data input device and a surface by determining displacement of optical features in a succession of images of the surface, the method comprising:
- emitting coherent light from a laser;
collimating the coherent light so as to form a collimated illumination beam with a predetermined diameter, D, and is transmitted to the surface at a normal angle thereto;
generating a speckle pattern by impingement of the coherent light from the collimated illumination beam on the surface; and
detecting the images of the surface using a sensor array comprising a comb array,wherein the laser and the sensor array are both configured on a same planar substrate that is configured to lie parallel to the surface, and the predetermined diameter, D, of the collimated illumination beam satisfies an equation D=(h λ
)/(ξ
Λ
cos2θ
), wherein h is a height from the planar substrate to the surface, λ
is a wavelength of the coherent light, ξ
is a fraction between 0.25 and 0.5, Λ
is a period of the comb array, and θ
is an angle subtended by the beam from a point on the sensor.
6 Assignments
0 Petitions
Accused Products
Abstract
One embodiment relates to a laser positioning device for sensing relative movement between a data input device and a surface by determining displacement of image features in a succession of images of the surface. The device forms a single integrated package, which includes a planar substrate and a transparent encapsulant that also embodies a collimating lens. Both a coherent light source and a sensor array and associated circuitry are configured on the planar substrate. Another embodiment relates to a method of sensing relative movement between a data input device and a surface. Coherent light is emitted from a laser and collimated so as to form a collimated illumination beam with a predetermined diameter, D, and a substantially uniform phase front. A speckle pattern is generated by impingement of the collimated illumination beam on the surface and detected by a sensor array. Other embodiments are also disclosed.
-
Citations
17 Claims
-
1. A method of sensing relative movement between a data input device and a surface by determining displacement of optical features in a succession of images of the surface, the method comprising:
-
emitting coherent light from a laser; collimating the coherent light so as to form a collimated illumination beam with a predetermined diameter, D, and is transmitted to the surface at a normal angle thereto; generating a speckle pattern by impingement of the coherent light from the collimated illumination beam on the surface; and detecting the images of the surface using a sensor array comprising a comb array, wherein the laser and the sensor array are both configured on a same planar substrate that is configured to lie parallel to the surface, and the predetermined diameter, D, of the collimated illumination beam satisfies an equation D=(h λ
)/(ξ
Λ
cos2θ
), wherein h is a height from the planar substrate to the surface, λ
is a wavelength of the coherent light, ξ
is a fraction between 0.25 and 0.5, Λ
is a period of the comb array, and θ
is an angle subtended by the beam from a point on the sensor. - View Dependent Claims (2, 3, 4)
-
-
5. A laser positioning device for sensing relative movement between a data input device and a surface by determining displacement of optical speckle in a succession of images of the surface, the device comprising:
-
a planar substrate; a coherent light source configured on the planar substrate to shine a collimated illumination beam on the surface; and a comb array and associated circuitry configured on the planar substrate, wherein a predetermined diameter, D, of the collimated illumination beam satisfies an equation D=(h λ
)/(ξ
Λ
cos2θ
), wherein h is a height from the planar substrate to the surface, λ
is a wavelength of the coherent light, ξ
is a fraction between 0.25 and 0.5, Λ
is a period of the comb array, and θ
is an angle subtended by the beam from a point on the sensor. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A laser positioning device comprising:
-
a substrate with a light source configured thereon; a collimating lens between the light source and a surface over which the device is positioned to illuminate the surface with an illumination beam; a sensor array configured on the substrate, the sensor array having a field of view of the illuminated surface; and a lift detection mechanism that causes the device to stop tracking if the device is lifted from a nominal height distance (h) above the surface by more than a predetermined distance (Δ
h) above the surface, the lift detection mechanism comprises an opaque edge located a horizontal distance (x) from a center of the sensor array, parallel to a plane of the sensor array, given by the equation;where w is a width of the sensor array, s is a center-to center separation between the sensor array and the light source, and D(h,s) is a diameter of the illumination beam. - View Dependent Claims (16, 17)
-
-
17. The laser positioning device according to claim 15, wherein Δ
- h is a predetermined distance between one to five millimeters.
Specification