Optical alignment method for pointing devices
First Claim
1. The pointing device wherein said lens is positioned in front of said diffuser.
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Accused Products
Abstract
This invention provides an optical pointing device, such as those used to control devices such as televisions, VCRs, video games and computers, which have improved accuracy and lower sensitivity to detrimental effects, such as noise and user hand unsteadiness, than prior art devices. Such pointing devices emit light beams, such as infrared light, which when received by a receiver are used to position cursors or other symbolic shapes, such as sliding volume controls. An advantage of the pointing device of the invention is that light emitting diodes of conventional manufacture, known to have poor optical precision and hence variable angular emission profiles, may nevertheless be used in the pointing device of the invention.
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Citations
27 Claims
- 1. The pointing device wherein said lens is positioned in front of said diffuser.
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7. An optical pointing device comprising:
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a. a plurality of light emitting diodes, said diodes being mounted in a predetermined arrangement on a substrate; b. a lens positioned in front of said light emitting diodes by a distance equal to the focal length of said lens; and c. a diffuser positioned in proximity to said lens, the pointing device having a predetermined desired angular operating range, Am, wherein said lens, said diffuser and the spacing of said light emitting diodes are chosen such that the figure of merit Fm=Pf /Nm is optimized. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. An optical pointing device comprising:
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a. a plurality of light emitting diodes, said diodes being mounted in a predetermined arrangement on a substrate; b. a lens positioned in front of said light emitting diodes by a distance equal to the focal length of said lens; and c. a diffuser positioned in proximity to said lens, the pointing device having a predetermined desired angular operating range, Am, wherein said lens, said diffuser and the spacing of said light emitting diodes are chosen such that the figure of merit Fm=Pf /Nm is optimized. - View Dependent Claims (16)
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17. A method for positioning light emitting diodes in a pointing device comprising:
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a. providing a plurality of light emitting diodes behind a lens, such that said light emitting diodes are located at the focal plane of said lens, said diodes having a forward facing light emitting region and electrical connection leads extending from a rearward facing region opposite to said forward facing region; b. preparing a positioning device having apertures therethrough in a predetermined arrangement, said apertures sized to snugly accommodate said light emitting diodes; c. providing a substrate for holding said light emitting diodes in said predetermined configuration, said substrate having apertures therethrough to loosely accommodate said electrical connection leads; d. positioning said light emitting diodes in said substrate such that said leads associated with said light emitting diodes pass through corresponding apertures in said substrate; e. positioning said positioning device over said light emitting diodes; and f. soldering said leads to said substrate.
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18. A method for positioning light emitting diodes in a pointing device comprising:
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a. providing a plurality of light emitting diodes, said diodes having a forward facing light emitting region and electrical connection leads extending from a rearward facing region opposite to said forward facing region; b. preparing a positioning device having apertures therethrough in a predetermined arrangement, said apertures sized to snugly accommodate said light emitting diodes; c. providing a substrate for holding said light emitting diodes in said predetermined configuration, said substrate having apertures therethrough to loosely accommodate said electrical connection leads; d. positioning said light emitting diodes in said substrate such that said leads associated with said light emitting diodes pass through corresponding apertures in said substrate; e. positioning said positioning device over said light emitting diodes; f. soldering said leads to said substrate; and
removing said substrate with said light emitting diodes from said positioning device.
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19. A method for selecting the optical parameters for an optical pointing device having improved accuracy and stability comprising the steps of:
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a. selecting an operating angular range, ±
Am;b. obtaining a value for threshold factor η
from known receiver properties and;
space="preserve" listing-type="equation">i) η
=I.sub.min /I.sub.maxand c. calculating the curve of Gaussian parameter B vs Ao using η and
the α
corresponding to the diffuser from whichever of i) and ii) below is the smaller;
##EQU2## and d. constructing a curve of figure of merit, Fm, versus offset angle Ao from;
space="preserve" listing-type="equation">i) Pf∝
(1/B.sup.2) exp (-(Ao/B).sup.2)and
space="preserve" listing-type="equation">ii) Nm=B.sup.2 /2AoAmand
space="preserve" listing-type="equation">iii) Fm=Pf/Nmand e. selecting the optimum offset angle, Ao, from said curve of Fm vs. Ao to thereby provide a maximum value of Fm; and f. selecting a value for B corresponding to Ao optimum using said curve of B vs Ao; and g. selecting light emitting diode spacing R and lens focal length F using said optimum offset angle Ao and;
space="preserve" listing-type="equation">i) Ao=Arctan (R/F)
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Specification