Speaker Diaphragm

Abstract

A smaller-sized and acoustically excellent speaker diaphragm is inexpensively provided using the mixture of a specially surface-coated woody material and a mass-producible synthetic resin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] Perspective view of a speaker diaphragm as EXAMPLE 1 of an embodiment.

[FIG. 2] Frequency characteristics graph of the levels of regenerated sound pressure and high-order harmonic waves, which a speaker with the diaphragm of EXAMPLE 1 built therein did show.

[FIG. 3] Frequency characteristics graph of the levels of regenerated sound pressure and high-order harmonic waves, which another speaker with the diaphragm of REFERENCE built therein did show.

[FIG. 4] Graph of a relationship that was observed between the Young's modulus and temperature, respectively for the diaphragm materials of EXAMPLE 1, COMPARATIVE example and REFERENCE.

[FIG. 5] Another graph of the relationship that was observed between the value of tan δ and temperature, respectively for the diaphragm materials of EXAMPLE 1, COMPARATIVE example and REFERENCE.

REFERENCE NUMERALS

1 . . . Diaphragm

2 . . . Edge

3 . . . Voice coil

4 . . . Damper

Claims

1. A speaker diaphragm made of a mixture comprising a non-chlorinated synthetic resin intermixed with a powdery cellulose material whose particles size falls within a range of from 5 μm to 500 μm.

2. A speaker diaphragm as defined in claim 1, wherein 30% to 70% by weight of the powdery cellulose material is contained in the mixture.

3. A speaker diaphragm as defined in claim 1, wherein the non-chlorinated synthetic resin is selected from the group consisting of polyolefin resins, polyester resins and polystyrene resins.

4. A speaker diaphragm as defined in claim 1, wherein the powdery cellulose material has been subjected to a surface treatment to enhance its affinity to the non-chlorinated synthetic resin.

5. A speaker diaphragm as defined in claim 1, wherein the mixture is colored with a colorant.

6. A speaker diaphragm as defined in claim 1, wherein the powdery cellulose material has a natural fragrance, and the molding of the mixture has been carried out at a temperature of from 160° C. to 200° C.

7. A speaker diaphragm as defined in claim 1, wherein the surface treatment for enhancing the affinity of the powdery cellulose material to the non-chlorinated synthetic resin is esterification using an anhydride of a polybasic acid.

8. A speaker diaphragm as defined in claim 7, wherein the mixture is composed of the non-chlorinated synthetic resin, the powdery cellulose material and an organic peroxide.

9. A speaker diaphragm as defined in claim 2, wherein the powdery cellulose material has been subjected to a surface treatment to enhance its affinity to the non-chlorinated synthetic resin.

10. A speaker diaphragm as defined in claim 2, wherein the mixture is colored with a colorant.

11. A speaker diaphragm as defined in claim 3, wherein the mixture is colored with a colorant.

12. A speaker diaphragm as defined in claim 2, wherein the powdery cellulose material has a natural fragrance, and the molding of the mixture has been carried out at a temperature of from 160° C. to 200° C.

13. A speaker diaphragm as defined in claim 3, wherein the powdery cellulose material has a natural fragrance, and the molding of the mixture has been carried out at a temperature of from 160° C. to 200° C.

14. A speaker diaphragm as defined in claim 4, wherein the powdery cellulose material has a natural fragrance, and the molding of the mixture has been carried out at a temperature of from 160° C. to 200° C.

15. A speaker diaphragm as defined in claim 2, wherein the surface treatment for enhancing the affinity of the powdery cellulose material to the non-chlorinated synthetic resin is esterification using an anhydride of a polybasic acid.

16. A speaker diaphragm as defined in claim 15, wherein the mixture is composed of the non-chlorinated synthetic resin, the powdery cellulose material and an organic peroxide.

17. A speaker diaphragm as defined in claim 3, wherein the surface treatment for enhancing the affinity of the powdery cellulose material to the non-chlorinated synthetic resin is esterification using an anhydride of a polybasic acid.

18. A speaker diaphragm as defined in claim 17, wherein the mixture is composed of the non-chlorinated synthetic resin, the powdery cellulose material and an organic peroxide.

19. A speaker diaphragm as defined in claim 4, wherein the surface treatment for enhancing the affinity of the powdery cellulose material to the non-chlorinated synthetic resin is esterification using an anhydride of a polybasic acid.

20. A speaker diaphragm as defined in claim 19, wherein the mixture is composed of the non-chlorinated synthetic resin, the powdery cellulose material and an organic peroxide.