DAMPER FOR ELECTRONIC DEVICE

Abstract: The invention relates to an electronic device for reading information stored on disc-shaped data carriers and/or writing information on disc-shaped data carriers, comprising a housing (1) and an optical unit (2) arranged in the housing (1), at least one damper (3) being provided between the housing (1) and the optical unit (2). According to the invention, the damper (3) comprises a porous material (5) and a fluid (6).

Description: DAMPER FOR ELECTRONIC DEVICE The invention relates to an electronic device for reading information stored on disc-shaped data carriers and/or writing information on disc-shaped data carriers, comprising a housing and an optical unit arranged in the housing, at least one damper being provided between the housing and the optical unit. Such a device is known, for example, from the document EP 0962361. The damper in this known device comprises oil-filled rubber dampers, each with a plunger which is movably supported for the purpose of generating viscous friction in the oil. The damping generated in this known damper is linearly dependent on the oil velocity generated by the plunger. Such a construction, furthermore, has a definite resonance point where the acceleration acting on the mass to be damped is greater than the excitation. It is an object of the invention to provide a device of the kind mentioned in the opening paragraph which has better damping properties. According to the invention, this object is achieved in that the damper comprises a porous material and a fluid. The relative fluid velocity, occurring upon a deformation of the damper, and thus also the generated damping, is increased by the porous material. The damper has a structure which is formed as it were by a plurality of small dampers because of the porous material. A deformation of the damper as a result leads to a substantially higher fluid velocity. The viscous friction and the damping resulting therefrom are enhanced thereby. The term porous material is understood to mean a material with a cell structure capable of accommodating a fluid, said cell structure achieving a distribution of the fluid in the shape of droplets. In addition, a non-linear damping effect occurs. The damping drops non- linearly when the relative velocity between the housing and the optical unit is reduced. If this non-linear behavior is attuned to the mass of the optical unit to be damped, the required free space between the housing and the optical unit can be made smaller, without the maximum acceleration acting on the optical unit being increased. Since a complete structure is deformed, such a damper can also be realized without a plunger. The minimum height of the compressed damper can be reduced thereby. This leads to an additional reduction in the constructional height. Preferably, the porous material has a low inherent stiffness. A particularly advantageous material is foam material. Preferably, the fluid has a high viscosity value. This increases the damping effect which is based on viscous friction. Particular advantages are obtained in devices which are designed for incorporation in motor vehicles as well as in portable devices, because the constructional space available for these devices is limited and the dampers according to the invention can be implemented in a very space-saving manner. A diagrammatically depicted embodiment of the invention will be explained in more detail below with reference to Figs, la, lb and 2a, 2b of the drawing, in which: Fig. la shows the damping construction for an electronic device which is sensitive to shocks, the damper being undeformed in a rest position, Fig. lb is an enlarged detail of the damper of Fig. la, Fig. 2a shows the damping construction of Fig. la, with the damper deformed as a result of an impact acting on the housing, and Fig. 2b is an enlarged detail of the damper of Fig. 2a. Fig. la is a diagrammatic picture of a damping construction of an electronic device for reading information stored on disc-shaped data carriers and/or writing information on disc-shaped data carriers, representing an embodiment of the invention. Such a device may be, for example, a CD player or a DND player. The device comprises a housing 1 and an optical unit 2 accommodated in the housing 1. The housing 1 and the optical unit 2 are coupled by means of a damper 3. The damper 3 has an elastic outer membrane 4 as its outer envelope. The damper 3 is fastened at one side to the housing 1 and at the other side to the optical unit 2. The damper 3 is filled with a foam material 5 and with oil 6. The oil 6 has the function of generating viscous friction. The viscous friction is dependent on the fluid velocity of the oil 6. The foam material 5 is provided for the purpose of increasing the fluid velocity and increasing the viscous friction resulting therefrom. Fig. lb is a detailed view on an enlarged scale of the damper 2 of Fig. la filled with foam material 5 and oil 6. The oil 6 shows a structure 7 of droplets which are interconnected by narrow channels 8. Figs, la and lb show the damper 3 in the undeformed state. Figs. 2a and 2b show the damper 3 in a deformed state. Such a deformation occurs, for example, when the housing 1 moves as a result of an impact. The task of the damper 3 now is to keep such an impact away from the optical unit 2, so that a reading or writing operation free from errors of the optical unit 2 is safeguarded. When the housing 1 moves towards the optical unit 2 as a result of an impact or other forces acting on the housing 1, the damper 2 will be compressed. The foam-oil structure present inside the damper 3 is also deformed thereby. The damping action of the damper 2 is based on viscous friction of the oil 5. The foam material 6 increases the oil velocity occurring upon the deformation of the damper 3, and thus also the viscous friction.

Claims: CLAIMS: 1. An electronic device for reading information stored on disc-shaped data carriers and/or writing information on disc-shaped data carriers, comprising a housing (1) and an optical unit (2) arranged in the housing (1), at least one damper (3) being provided between the housing (1) and the optical unit (2), characterized in that the damper (3) comprises a porous material (5) and a fluid (6). 2. A device as claimed in claim 1, characterized in that the porous material (5) is a material with a low inherent stiffness. 3. A device as claimed in claim 1, characterized in that the porous material (5) is a foam material. 4. A device as claimed in claim 1, characterized in that the fluid (6) is a material of high viscosity, in particular oil. 5. A device as claimed in claim 1, characterized in that the damper (3) has an elastic membrane (4) as its outer envelope, in particular a rubber membrane. 6. A vehicle with a device as claimed in claim 1. 7. A fluid-filled damper (3) with an elastic membrane (4) as its outer envelope, characterized in that the damper (3) comprises a porous material (5) and a fluid (6). 8. The use of a damper (3) as claimed in claim 7 in portable electronic devices or in electronic devices designed for incorporation in motor vehicles.

Inventors: RUMPF HORST, RUMPF, HORST
Applicants: KONINKL PHILIPS ELECTRONICS NV, PHILIPS CORP INTELLECTUAL PTY, RUMPF HORST, KONINKLIJKE PHILIPS ELECTRONICS N.V., PHILIPS CORPORATE INTELLECTUAL PROPERTY GMBH, RUMPF, HORST
Application year: 2000
Main classification: G11B33
IPC codes: F16F5, F16F9, F16F13, G11B25, G11B33, H05K7