Sound absorbing panel with wedge-shaped cross-section micro-slits
View Patent ↗An acoustical panel has a multiplicity of short micro-slits, about 10 mm in length each, with each micro-slit having a wedge shaped cross-section in which the opening on the front side of the panel is wider than the opening on the rear side of the panel by a factor of about 2 to effectively absorb sound frequencies in the range of 250-2000 Hz, with the micro-slits greater than 4%. The micro-slits are spaced apart less than 5 mm and several different patterns of micro-slits may be employed including micro-slits that are straight as well as arcuate or some combination of straight and arcuate. The area of the micro-slits on the front surface of the panel exceeds 4%.
1. A sound absorbing panel comprising:
a) a panel having a front surface and a back surface;
b) a multiplicity of micro-slits formed in said panel and extending from said front surface to said back surface, each micro-slit having an entrance at said front surface and an exit at said back surface;
c) each of said micro-slits having a direction of elongation and a wedge-shaped cross-section perpendicular to said direction of elongation, each micro-slit having a substantially uniform first width at said front surface entrance and a substantially uniform second width at said back surface exit, said second width at said back surface being greater than said first width at said front surface; and
d) a surface area subtended by all of said micro-slits at said front surface combined being at least 4% of a surface area of said front surface;
e) whereby sound enters said micro-slits at each entrance and exits said micro-slits at each exit, said sound being absorbed at a frequency range of 250-2000 Hz.
2. The panel of claim 1 , wherein said panel is transparent.
3. The panel of claim 1 , wherein said panel is rectangular.
4. The panel of claim 1 , wherein said first width is about 0.25 mm±0.05 mm.
5. The panel of claim 4 , wherein said second width is about 0.5 mm±0.1 mm.
6. The panel of claim 5 , wherein a ratio between said second width and said first width is about 2:1±10%.
7. The panel of claim 1 , wherein said panel exhibits optimal sound absorption at a frequency range of about 600-900 Hz.
8. The panel of claim 1 , wherein each micro-slit has a length of about 10 mm.
9. The panel of claim 8 , wherein a ratio between length and width at front surface for each micro-slit is about 40.
10. The panel of claim 1 , wherein said micro-slits form a “RAIN” pattern.
11. The panel of claim 1 , wherein said micro-slits form a “WAVE” pattern.
12. The panel of claim 1 , wherein said micro-slits form a “FLOW” pattern.
13. The panel of claim 1 , wherein said micro-slits form a “THISTLE” pattern.
14. The panel of claim 1 , wherein said micro-slits form a “CLOVER” pattern.
15. The panel of claim 1 , wherein said micro-slits form a “PARQUET” pattern.
16. A sound absorbing panel comprising:
a) a transparent panel having a front surface and a back surface;
b) a multiplicity of micro-slits formed in said panel and extending from said front surface to said back surface, each micro-slit having an entrance at said front surface and an exit at said back surface;
c) each of said micro-slits having a direction of elongation and a wedge-shaped cross-section perpendicular to said direction of elongation, each micro-slit having a substantially uniform first width of about 0.25 mm±0.05 mm at said front surface entrance and a substantially uniform second width of about 0.5 mm±0.1 mm at said back surface exit, said second width at said back surface being greater than said first width at said front surface at a ratio of about 2:1±10%; and
d) a surface area subtended by all of said micro-slits at said front surface combined being at least 4% of a surface area of said front surface;
e)whereby sound enters said micro-slits at each entrance and exits said micro-slits at each exit, said sound being absorbed at a frequency range of 250-2000 Hz.
17. The panel of claim 16 , wherein said panel is rectangular.
18. The panel of claim 16 , wherein said panel exhibits optimal sound absorption at a frequency range of about 600-900 Hz.
19. The panel of claim 16 , wherein each micro-slit has a length of about 10 mm and a ratio between length and width at front surface for each micro-slit is about 40.