Loudspeaker having a laminate diaphragm of three layers
First Claim
1. A loudspeaker comprising:
- a diaphragm including first and second layers and a core sandwiched between said layers, said core being secured to an inner surface of each of said layers to form a unitary structure therewith;
means for vibrating said diaphragm in accordance with a varying electrical signal supplied thereto; and
support means for supporting both said diaphragm and said means for vibrating;
the improvement wherein each of said layers is formed of materials through which the velocity of propagation of a longitudinal wave is greater than 5000 m/sec. and wherein said core is formed of materials having a shearing elastic modulus Gco which exceeds the value ##EQU15## where Ef is the longitudinal elasticity of each of said layers,tf is the thickness of each of said layers,tc is the thickness of said core, andl is the length across the surface of said diaphragm.
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Abstract
A loudspeaker having a diaphragm including first and second layers and a core sandwiched between the layers, the core being firmly secured to the inner surface of each layer so as to form a unitary structure therewith, a drive assembly causes the diaphragm to vibrate in accordance with a varying electrical input signal fed thereto, and a support is provided for supporting the diaphragm and drive assembly. The layers are formed of materials through which the velocity of propagation of a longitudinal wave is greater than 5000 m/sec, and the core is formed of materials having a shearing elastic modulus Gco which exceeds the value ##EQU1## WHERE Ef is the longitudinal elasticity of each of the layers,
tf is the thickness of each of the layers,
tc is the thickness of the core, and
l is the length across the surface of the diaphragm.
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Citations
14 Claims
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1. A loudspeaker comprising:
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a diaphragm including first and second layers and a core sandwiched between said layers, said core being secured to an inner surface of each of said layers to form a unitary structure therewith; means for vibrating said diaphragm in accordance with a varying electrical signal supplied thereto; and support means for supporting both said diaphragm and said means for vibrating;
the improvement wherein each of said layers is formed of materials through which the velocity of propagation of a longitudinal wave is greater than 5000 m/sec. and wherein said core is formed of materials having a shearing elastic modulus Gco which exceeds the value ##EQU15## where Ef is the longitudinal elasticity of each of said layers,tf is the thickness of each of said layers, tc is the thickness of said core, and l is the length across the surface of said diaphragm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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5. A loudspeaker according to claim 2, wherein said diaphragm has an opening through said first and second layers and through said core, and said bobbin is attached to the surface of said opening by an adhesive comprised of an adhesive agent mixed with glass bubbles.
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6. A loudspeaker according to claim 5 wherein said adhesive agent is rubber material.
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7. A loudspeaker according to claim 5 wherein said adhesive agent is an epoxy adhesive agent.
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8. A loudspeaker according to claim 2 wherein said diaphragm has an opening through said first and second layers and through said core, and said bobbin is attached to the surface of said opening by an adhesive including a foaming agent.
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9. A loudspeaker according to claim 2, wherein said support means further includes an edge member for connecting the outer perimeter of said diaphragm to said frame.
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10. A loudspeaker according to claim 9 wherein said edge member includes a portion connected to one side of said diaphragm and to an exposed surface of at least one layer.
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11. A loudspeaker according to claim 10 wherein said portion of said edge member is a gripper member for gripping said diaphragm therebetween.
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12. A loudspeaker according to claim 1, wherein said diaphragm is of a conical shape having a center hole, said bobbin extending into said center hole and being connected thereat to said diaphragm.
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13. A loudspeaker according to claim 1, whereat at least the outer peripheral edge surface of said diaphragm is coated with an adhesive agent mixed with a material selected from the group consisting of glass beads and a foam adhesive agent.
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14. A loudspeaker according to claim 13 wherein the outer peripheral edge surface of said diaphragm is free to vibrate and is unconnected from said support means.
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Specification