MULTIPLE CODES IN AN ARRAY PATTERN WITH SPARSE DISTRIBUTION OF MICROPARTICLES

1 . A system for depositing tags in an array, comprising:

a substrate holder configured to hold a substrate;

a tag depositor configured to deposit tags on the substrate; and

a positioner configured to position the tag depositor relative to the substrate, wherein the positioner positions the tag depositor to deposit tags on the substrate in an array.

2 . The system of claim 1 , wherein the tags comprise optical interference filters.

3 . The system of claim 2 , wherein the optical interference filters comprise rugate filters.

4 . The system of claim 2 , wherein the optical interference filters comprise etched porous silicon filters.

5 . The system of claim 1 , wherein the tags comprise particles of less than 100 micrometers with embedded optically readable codes.

6 . The system of claim 1 , wherein the array comprises an orthogonal array, a non-orthogonal array, a line, a circle, a curve, a freeform curved line, or a two-dimensional array.

7 . The system of claim 1 , wherein the substrate holder comprises a belt.

8 . The system of claim 7 , wherein the belt moves.

9 . The system of claim 1 , further comprising a tag reservoir coupled to the tag depositor.

10 . The system of claim 9 , wherein the tag reservoir stores a plurality of tags of a single code.

11 . The system of claim 9 , wherein the tag reservoir comprises one of a plurality of tag reservoirs, wherein a coupling to the tag depositor is switchable between the plurality of tag reservoirs.

12 . The system of claim 11 , wherein a second tag reservoir of the plurality of tag reservoirs comprises tags of a second code.

13 . The system of claim 1 , wherein the tag depositor comprises one of a plurality of tag depositors.

14 . The system of claim 13 , wherein the plurality of tag depositors are arranged in a linear array.

15 . The system of claim 1 , wherein the tag depositor comprises a syringe, a pipette, or a needle valve.

16 . The system of claim 1 , wherein the tag depositor comprises a system for sparse dispersion of tags.

17 . The system of claim 16 , wherein the system for sparse dispersion of tags comprises:

an enclosure configured to contain a set of tags, wherein the set of tags settles to a bottom of the enclosure in a heap;

an input tube configured to inject gas near the bottom of the enclosure;

an exit tube configured such that a distance to the set of tags in the heap generates a sparse flow of tags from the set of tags that exits the exit tube when a gas is injected via the input tube.

18 . A method for depositing tags in an array, comprising:

holding a substrate using a substrate holder;

depositing tags on the substrate using a tag depositor; and

positioning the tag depositor relative to the substrate using a positioner, wherein the positioner positions the tag depositor to deposit tags on the substrate in an array.

19 . A system for sparse dispersion of tags, comprising:

an enclosure configured to contain a set of tags, wherein the set of tags settles to a bottom of the enclosure in a heap;

an input tube configured to inject gas near the bottom of the enclosure;

an exit tube configured such that the distance to the set of tags in the heap generates a sparse flow of tags from the set of tags that exits the exit tube when a gas is injected via the input tube.

20 . A method for sparse dispersion of tags, comprising:

providing an enclosure configured to contain a set of tags, wherein the set of tags settles to a bottom of the enclosure in a heap;

providing an input tube configured to inject gas near the bottom of the enclosure;

providing an exit tube configured such that the distance to the set of tags in the heap generates a sparse flow of tags from the set of tags that exits the exit tube when a gas is injected via the input tube.