1. A process for fabricating a composite microfilter structure comprising:
etching a pattern of micropores through a standard-size semiconductor wafer to form a support membrane; and
providing at least one separation membrane atop the support membrane.
2. The process recited in claim 1, wherein the step of providing a separation membrane comprises providing an organic separation membrane.
3. The process recited in claim 3, wherein the organic separation membrane provided comprises a thermoplastic polymer.
4. The process recited in claim 2, wherein the organic separation membrane provided comprises a polymer that will cleanly and efficiently transmit a permeate to a support layer.
5. The process recited in claim 3, wherein the thermoplastic polymer is selected from the group consisting of polyimide, SiLK, polysulfone, and polyethersulfone.
6. The process recited in claim 1, wherein the step of providing a separation membrane comprises providing an inorganic separation membrane.
7. The process recited in claim 6, wherein the step of providing an inorganic separation membrane comprises providing an inorganic membrane that will cleanly and efficiently transmit a permeate to a support layer.
8. The process recited in claim 6, wherein the inorganic separation membrane is selected from the group consisting of silicon, silicon dioxide, zeolite and any combination thereof.
9. The process recited in claim 6, wherein the step of etching a pattern of micropores in a semiconductor wafer comprises dry etching a silicon-containing wafer by fluorine radicals in a plasma using TMDE.
10. The process recited in claim 6, wherein the step of providing an inorganic separation membrane comprises depositing an inorganic material by a method selected from the group consisting of CVD and plasma-enhanced CVD.
11. A process for fabricating a silicon oxide membrane for a composite asymmetric microfilter structure, comprising:
depositing a silicon oxide atop a support membrane by a method selected from the group consisting of CVD and plasma-enhanced CVD with a TEOS source;
depositing and curing a photoresist layer atop the silicon oxide;
providing the photoresist layer with a pattern for a plurality of micropores;
exposing and developing the pattern in the photoresist layer;
transferring the pattern into the silicon oxide using a dry etch method; and
removing the remaining photoresist.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A camera frame assembly comprising:
a frame including a film return chamber, a film roll chamber spaced apart from said film return chamber, and an midsection extending between said chambers, said midsection having a pair of film guide surfaces, said film guide surfaces defining a film path between said chambers;
a holdfast joined in fixed relation to said midsection adjacent said film roll chamber, said holdfast extending outward from said midsection toward said film path, said holdfast being fully outside said film path;
a film unit having a film holder and a filmstrip, said film holder being seated in said film return chamber, said filmstrip having a leading portion having a free end and a grip adjoining said free end, said filmstrip having a main portion adjoining said leading portion, said filmstrip being movable between a first position wherein said grip engages said holdfast and a second position wherein said main portion occupies said film path and extends from one of said chambers to the other of said chambers.
2. The camera frame assembly of claim 1 further comprising a platen attachable to said frame to hold said filmstrip in said second position.
3. The camera frame assembly of claim 1 wherein said holdfast is recessed forward relative to said film guide surfaces.
4. The camera frame assembly of claim 3 wherein said holdfast has a pair of laterally spaced apart subunits.
5. The camera frame assembly of claim 4 wherein said film guide surfaces each include a cap, said caps being joined to respective said subunits of said holdfast.
6. The camera frame assembly of claim 4 wherein said midsection has a recess and said subunits are disposed in said recess.
7. The camera frame assembly of claim 1 wherein said holdfast overhangs said film roll chamber.
8. The camera frame assembly of claim 1 wherein said midsection has a pair of fences laterally adjoining respective said film guide surfaces, said fences each extending rearward.
9. The camera frame assembly of claim 8 wherein said holdfast has a pair of laterally spaced apart subunits, said subunits each being continuous with a respective said fence.
10. A camera frame assembly for use with a film unit having a filmstrip and a film holder, said filmstrip having a leading portion having a free end and a grip adjoining said free end, said camera frame assembly comprising:
a film return chamber configured to receive said film holder;
a film roll chamber spaced apart from said film return chamber;
an midsection extending between said chambers, said midsection having an exposure opening and a pair of film guide surfaces adjoining said exposure opening; and
a holdfast mounted in fixed relation to said midsection, said holdfast extending rearward, said holdfast having a cross-section matching a corresponding dimension of said grip, said holdfast being recessed forward relative to said film guide surfaces;
whereby said holdfast can engage said grip, but said holdfast is spaced from said filmstrip when said filmstrip is disposed against said film guide surfaces.
11. The camera frame assembly of claim 10 wherein said holdfast has a pair of laterally spaced apart subunits.
12. The camera frame assembly of claim 11 wherein said film guide surfaces each include a cap, said caps being joined to respective said subunits of said holdfast.
13. The camera frame assembly of claim 11 wherein said midsection has a recess and said subunits are disposed in said recess.
14. The camera frame assembly of claim 10 wherein said holdfast overhangs said film roll chamber.
15. A transportable camera intermediate comprising:
a frame including a film return chamber, a film roll chamber, and a midsection extending between said chambers, said midsection having a pair of opposed film guide surfaces defining a film path between said film chambers;
a holdfast joined in fixed relation to said midsection, said holdfast extending outward from said midsection toward said film path, said holdfast being fully outside said film path;
a film unit having a film holder and a filmstrip, said film holder being seated in said film return chamber, said filmstrip having a main portion held by said film holder and a leading portion adjoining said main portion and extending outward from said film holder, said leading portion having a free end disposed in said film roll chamber and a grip adjoining said free end, said grip engaging said holdfast.
16. The intermediate of claim 15 wherein said leading portion of said filmstrip intersects said film path.
17. The intermediate of claim 15 wherein said holdfast is recessed relative to said midsection.
18. The intermediate of claim 15 wherein said holdfast overhangs said film roll chamber.
19. The intermediate of claim 15 wherein said holdfast has a pair of spaced apart subunits and said film guide surfaces includes a pair of caps each said cap being joined to a respective said subunit.
20. The intermediate of claim 15 wherein said midsection has a recess and said holdfast is disposed in said recess.
21. The intermediate of claim 15 wherein said holdfast is laterally spaced from said film path.
22. A camera comprising:
a frame including a film return chamber, a film roll chamber spaced apart from said film return chamber, and an midsection extending between said chambers, said midsection having a pair of film guide surfaces;
a film unit having a filmstrip and a film holder, said filmstrip extending between said chambers, said filmstrip having a leading portion having a free end and a grip adjoining said free end;
a platen attached to said frame, said platen holding said filmstrip against said film guide surfaces,
a holdfast joined in fixed relation to said midsection, said holdfast extending outward from said midsection toward said filmstrip, said holdfast being spaced from said filmstrip, said holdfast and grip having respective contact surfaces having matching dimensions.