Patent ID: 8567693

Claim:
A dispenser for controlled release of volatile substances, comprising: a reservoir that is flat and has a top face and a bottom face, the reservoir containing at least one volatile substance; a layer of material impermeable to the volatile substances which covers the top face of the reservoir; a first control element which: is composed of a material which is permeable to the at least one volatile substance; covers the bottom face of the reservoir; and exerts control over the release rate of said at least one volatile substance by means of diffusion dependent on the physical properties of the at least one volatile substance and the material properties of said permeable material of the first control element; and a second control element which: is composed of a material which is impermeable to the at least one volatile substance; and exerts control over the release rate of said at least one volatile substance, by controlling the size of the surface of the first control element, independent of the physical properties of the at least one volatile substance and the material properties of said permeable material of the first control element; wherein the second control element is in the form of a film that possesses gaps through which the volatile substance moves, wherein the number of said gaps is from 500 to 8000 gaps per m 2 of said film; wherein said first control element is pressure-sensitively adhesive, and is fully covered by said second control element such that, during the use of the dispenser, the at least one volatile substance moves from the reservoir first through the first control element and then through the gaps in the second control element; and wherein the first control element and the second control element jointly control release of the at least one volatile substance from the reservoir.