1. Field of the Invention
The present invention relates to a heat dissipator for an optical writing and/or reproducing apparatus, and more particularly, the present invention relates to a heat dissipator for an optical writing and/or reproducing apparatus, which is constructed to properly dissipate heat generated in a heat generating element, especially, a drive IC (integrated circuit) while the optical writing and/or reproducing apparatus is driven.
2. Description of the Related Art
Generally, in an optical writing and/or reproducing apparatus such as a disk drive, a great amount of heat is generated during operation. In an optical writing and/or reproducing apparatus, heat generating parts include a loading motor for producing power needed to load and eject an optical disk, a spindle motor for rotating the optical disk, an optical pick-up for writing and/or reproducing data on and/or from the optical disk, a step motor for driving the optical pick-up, and elements installed on a circuit board for controlling operation of the optical writing and/or reproducing apparatus.
If generated heat is not properly dissipated out of the optical writing and/or reproducing apparatus, not only the corresponding heat generating source but also surrounding parts can be adversely affected by the heat, and thereby, an operational error can be caused in the optical writing and/or reproducing apparatus.
Specifically, among the elements installed on the circuit board for controlling operation of the optical writing and/or reproducing apparatus, a drive IC for controlling driving of the motors generates a substantial amount of heat when compared to the other elements.
FIG. 1 is a cross-sectional view illustrating a conventional heat dissipator for an optical writing and/or reproducing apparatus.
Referring to FIG. 1, an optical writing and/or reproducing apparatus includes a main base 30, and a circuit board 40 positioned below the main base 30. Elements for controlling operation of the optical writing and/or reproducing apparatus are installed on the circuit board 40. A spindle motor, a loading motor and a step motor (not shown) are installed on the main base 30.
Among the elements installed on the circuit board 40, since a drive IC 42 continuously controls driving of the motors, it consumes a large amount of power and thereby generates a substantial amount of heat when compared to the other elements. For this reason, the drive IC 42 is installed on a lower surface 40b of the circuit board 40 so as not to adversely influence, by heat, surrounding elements including an RF (radio frequency) IC and a DSP (digital signal processor) IC which are installed on an upper surface 40a of the circuit board 40. At this time, the drive IC 40 is installed in a manner such that outer leads 43 externally formed thereon are bonded to the lower surface 40b of the circuit board 40.
Hereafter, the conventional heat dissipator for dissipating heat generated in the drive IC 42 will be described in detail.
The heat dissipator includes a lower cabinet 51b which is positioned to face the lower surface 40b of the circuit board 40 and a heat dissipating conduction member 54 which is interposed between the lower cabinet 51b and a molding section 42a of the drive IC 42. The lower cabinet 51b delimits an outer contour of the optical writing and/or reproducing apparatus and is made of a metallic material. The heat conduction member 54 functions to dissipate or conduct the heat generated in the drive IC 42. Over a region where the lower cabinet 51b faces the molding section 42a of the drive IC 42, the lower cabinet 51b is formed with an upward protrusion 51c which projects toward the drive IC 42 to allow the heat dissipating conduction member 54 to be brought into close contact with the molding section 42a of the drive IC 42.
At this time, the heat conduction member 54 is not brought into contact with the outer leads 43 which serve to connect the drive IC 42 to the circuit board 40.
Concretely speaking, between the drive IC 42 installed on the lower surface 40b of the circuit board 40 and the lower cabinet 51b facing the drive IC 42, there is interposed the heat conduction member 54 in a manner such that it is brought into close contact with the molding section 42a of the drive IC 42. As a consequence, heat generated in the molding section 42a of the drive IC 42 is transmitted through the heat conduction member 54 to the lower cabinet 51b to be dissipated to the outside.
However, the conventional heat dissipator constructed as mentioned above suffers from defects as described below.
While heat generated inside the drive IC 42 is first conducted to a molding material, that is, the molding section 42a serving as an encapsulant, and then transmitted to the lower cabinet 51b, in actual fact, since a considerable portion of the heat generated inside the drive IC 42 is conducted to the outer leads 43 made of a metallic material, the outer leads 43 have a higher temperature than the molding material. Resultingly, as heat of the outer leads 43 is transmitted to a circuit pattern formed on the circuit board 40, the circuit pattern is likely to be thermally damaged.
Also, because the heat conduction member 54 is installed over the region which faces only a lower surface of the molding section 42a of the drive IC 42, heat of side surfaces of the drive IC 42 and heat of the outer leads 43 cannot be properly conducted to the heat dissipating conduction member 54. Therefore, heat as a whole, generated in the entire drive IC 42, cannot be properly transmitted to the lower cabinet 51b. 
The reason for this is that only heat of the lower surface of the molding section 42a of the drive IC 42 is conducted to the heat conduction member 54 to be dissipated to the outside, and heat of the side surfaces of the drive IC 42 and heat of the outer leads 43 are dissipated to the outside only by convection through air.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a heat dissipator for an optical writing and/or reproducing apparatus, which is constructed to properly dissipate heat generated in the optical writing and/or reproducing apparatus, thereby improving operational reliability of the optical writing and/or reproducing apparatus.
According to one aspect of the present invention, there is provided a heat dissipator for an optical writing and/or reproducing apparatus, comprising: a main base having mounted thereto a plurality of parts including at least one motor for optical writing and/or reproduction; a circuit board positioned below the main base and having installed thereon elements for controlling the parts; a heat generating element formed with a plurality of leads which are connected to a circuit pattern of the circuit board; a heat conduction member brought into contact with at least the leads, for receiving heat generated in the heat generating element; and a cabinet brought into contact with the heat conduction member and formed with an element accommodating section and/or a pair of protrusions which are shaped to be functionally associated with an outer surface of the heat generating element to ensure that the heat conduction member is brought into close contact with the leads of the heat generating element.
According to another aspect of the present invention, there is provided a heat dissipator for an optical writing and/or reproducing apparatus, comprising: a heat generating element installed on a circuit board and having a molding section which is formed with a plurality of leads connected to a circuit pattern of the circuit board; a cabinet formed with a pair of protrusions which project toward the heat generating element to allow a portion of heat generated in the heat generating element, which portion is conducted to the leads, to be dissipated to the outside; and a heat conduction member interposed between the cabinet and the heat generating element and brought into contact with at least the leads and/or the pair of projections.
According to still another aspect of the present invention, there is provided a heat dissipating structure adapted for dissipating heat generated in an optical writing and/or reproducing apparatus, comprising: a heat generating element having a molding section which is formed with a plurality of leads; a cabinet formed with an element accommodating section for accommodating the heat generating element and a pair of protrusions which delimit the element accommodating section; and a heat conduction member interposed between the heat generating element and the cabinet, for being brought into contact with the leads and the molding section and at the same time the element accommodating section and the pair of protrusions, whereby heat of the leads is transmitted to the protrusions to enhance a heat dissipation efficiency.
As described above, in the heat dissipator for an optical writing and/or reproducing apparatus according to the present invention, an element accommodating section is formed on a lower cabinet in a manner such that it is functionally associated with outer surfaces and outer leads of a heat generating element, and a heat conduction member is interposed between the element accommodating section and the heat generating element.
Hence, according to the present invention, advantages are provided in that, since heat is transmitted from the outer surfaces, that is, a lower surface and both side surfaces and the outer leads of the heat generating element to the heat conduction member, and dissipated through the lower cabinet to the outside, heat as a whole, generated in the heat generating element, can be properly dissipated to the outside. Also, because performance degradation of the heat generating element and surrounding parts due to overheating is prevented, operational reliability of the optical writing and/or reproducing apparatus can be improved.
Further, in the present invention, due to the fact that a size of the heat dissipating member is increased to be able to cover the entire drive IC including the outer leads, a heat dissipation efficiency is enhanced.