Dental light devices having an improved heat sink
The present invention relates to a heat sink material that can more efficiently remove or divert heat from a light source or sources with a given weight of heat sink material when compared to a heat sink made of a solid block of thermally conductive material such as metal. It further relates to a heat sink that can more efficiently remove or divert heat from a curing light device when a reduced weight of heat sink material is used. The inventive heat sink has at least one suitable phase change material including organic materials, inorganic materials and combinations thereof. These materials can undergo substantially reversible phase changes, and can typically go through a large, if not an infinite number of cycles without losing their effectiveness.
1 - 49 . (canceled)
50 . A heat sink useful in a dental light system comprises:
a thermally conductive housing comprising an open end, a closed end, and a substantially hollow interior; and
a capping device comprising a formation adapted for compression fitting in the open end of the thermally conductive housing;
wherein said housing is partially filled with at least one phase change material adapted to absorb heat and undergoes substantially reversible phase changes.
51 . The heat sink of claim 50 wherein said phase change material is selected from a group consisting of organic materials, inorganic materials and combinations thereof.
52 . The heat sink of claim 51 wherein said organic phase change material is selected from the group consisting of paraffin waxes, 2,2-dimethyl-n-docosane (C24H50), trimyristin, ((C13H27COO)3C3H3), 1,3-methyl pentacosane (C26H54), polyethylene waxes, ethylene-bis-stearamide, N,N-ethylene-bis-stearamide, and mixtures thereof.
53 . The heat sink of claim 51 wherein said inorganic phase change material comprises inorganic hydrated salts.
54 . The heat sink of claim 51 wherein said inorganic phase change material is selected from the group consisting of sodium hydrogen phosphate dodecahydrate (Na2HPO4.12H2O), sodium sulfate decahydrate (Na2SO4.10H2O), ferric chloride hexahydrate (FeCl3.6H2O), TH29, metallic alloys and mixtures thereof.
55 . The heat sink of claim 50 wherein said phase change material is substantially surrounded by solid thermally conductive walls.
56 . The heat sink of claim 50 wherein said phase change material is a solid at ambient temperature.
57 . The heat sink of claim 50 wherein said phase change material has a melting point between about 30 to about 50 degrees C.
58 . The heat sink of claim 50 wherein said phase change material has a melting point between about 35 to 45 degrees C.
59 . The heat sink of claim 50 wherein said phase change material has a specific heat of more than about 1.7 at ambient temperature.
60 . The heat sink of claim 50 wherein said phase change material has a specific heat of more than about 1.5 at elevated temperatures.
61 . The, heat sink of claim 50 wherein said phase change material has a thermal conductivity of at least about 0.5 W/m° C. at ambient temperature.
62 . The heat sink of claim 50 wherein said phase change material has a thermal conductivity of at least about 0.45 W/m° C. at elevated temperatures.
63 . The heat sink of claim 50 wherein said housing comprises a blade-like divider for partitioning the substantially hollow interior.
64 . The heat sink of claim 50 wherein said phase change material is substantially surrounded by a vapor permeable and moisture impermeable film.
65 . The heat sink of claim 50 wherein said housing comprises vent holes.
66 . The heat sink of claim 65 wherein at least a portion of the housing comprising the vent holes is substantially surrounded by a vapor permeable and moisture impermeable film.
67 . The heat sink of claim 50 wherein said housing comprises a cylindrical or a rectangular cross-section.
68 . A light weight heat sink for use in a handheld dental light system comprises:
a thermally conductive block having a bore that is at least partially filed with at least one phase change material capable of undergoing substantially reversible phase changes; and
a capping device for capping said bore for containing said phase change material inside said bore.
69 . The heat sink of claim 68 wherein said phase change material is selected from a group consisting of organic materials, inorganic materials and combinations thereof.
70 . The heat sink of claim 68 wherein said phase change material has a melting point between about 30 to 50 degrees C.
71 . The heat sink material of claim 68 wherein said phase change material has a specific heat of more than about 1.7 at ambient temperature.
72 . The heat sink of claim 68 wherein said phase change material has a thermal conductivity of at least about 0.5 W/m° C. at ambient temperature.
73 . The heat sink of claim 68 wherein at least a portion of the block comprising the vent holes is substantially surrounded by a vapor permeable and moisture impermeable film.
74 . The heat sink of claim 68 wherein said block comprises at least one channel running the length of the block along its outside, said channel is adapted for positioning wiring components.
75 . The heat sink of claim 68 wherein said block comprises a substantially centrally located deep well having at least one side wall, two proximal portions at the top of the well and a distal portion at the bottom of the well, the portions being adapted for mounting at least one light source.
76 . A heat sink useful in a dental light system comprises:
a housing comprising an open end and a substantially hollow interior; and
a capping device comprising a formation adapted for fitting in the open end of the thermally conductive housing for sealing the hollow interior;
wherein said substantially hollow interior of said thermally conductive housing is partially filled with at least one phase change material and said material is contained inside the housing during phase change.
77 . The heat sink of claim 76 wherein said phase change material is selected from a group consisting of organic materials, inorganic materials and combinations thereof.
78 . The heat sink of claim 77 wherein said inorganic phase change material is selected from the group consisting of sodium hydrogen phosphate dodecahydrate (Na2HPO4.12H2O), sodium sulfate decahydrate (Na2SO4.10H2O), ferric chloride hexahydrate (FeCl3.6H2O), TH29, metallic alloys and mixtures thereof.
79 . The heat sink of claim 76 wherein said phase change material is a solid at ambient temperature.
80 . The heat sink of claim 76 wherein said phase change material has a melting point between about 30 to about 50 degrees C.
81 . The heat sink of claim 76 wherein said phase change material has a melting point between about 35 to 45 degrees C.
82 . The heat sink of claim 76 wherein said phase change material has a specific heat of more than about 1.7 at ambient temperature.
83 . The heat sink of claim 76 wherein said phase change material has a specific heat of more than about 1.5 at elevated temperatures.
84 . The heat sink of claim 76 further comprising at least one channel running the length of the conductive housing along its outside, said channel being adapted for positioning a wiring component.