Optical pickup device
View Patent ↗An optical pickup having a blade including a first blade in which an objective lens is mounted and which is made of a reinforced plastics material, and a second blade in which driving coils are mounted and which is made of a magnesium alloy material. Since the first blade has a low thermal conductivity coefficient, the heat generated in the coils is prevented from being transferred to the objective lens, whereas the second blade having a high thermal conductivity coefficient radiates the heat generated by the coils to the outside. Thus, the heat distortion of the objective lens can be suppressed, and damages to the coils or rigidity reduction of the blade can be avoided.
1. An optical pickup device comprising:
a blade in which an objective lens is mounted;
a plurality of wires to elastically and movably support the blade with respect to a holder formed on a base;
driving coils installed in or on the blade and forming an electrical path to drive the objective lens along a focusing direction and a tracking direction; and
a magnet which is installed in the base and generates an electromagnetic force due to currents flowing through the driving coils to move the objective lens;
wherein:
the blade includes a first blade portion made of a reinforced plastics material in which the objective lens is mounted, and a second blade portion made of a magnesium alloy material in which the driving coils are mounted,
a thermal conductivity coefficient of the first blade portion is lower than a thermal conductivity of the second blade portion, and
the first blade portion is combined with a combining unit included in the second blade portion by mounting the second blade portion in a die, and injecting the die with the reinforced plastics material.
2. The optical pickup device of claim 1 , wherein the combining unit has a protrusion extending from the second blade portion toward the first blade portion, and a combining hole formed in the protrusion to be filled with the reinforced plastics material.
3. An optical pickup device comprising:
a holder; and
a blade comprising:
a first blade portion in which an objective lens is positioned and made of a reinforced plastics material, and
a second blade portion having driving coils mounted thereon and made of a magnesium alloy material, wherein a thermal conductivity coefficient of the first blade portion is lower than that of the second blade portion; and
a combining unit positioned at each of two ends of the second blade portion to integrally hold the first blade portion thereto.
4. The optical pickup of claim 3 , wherein the combining unit comprises:
a protrusion extending from the second blade portion towards the first blade portion; and
a combining hole formed in the protrusion in which the first blade portion engages to be integrally held by the second blade portion.
5. An optical pickup device having an objective lens and driving coils, the optical pickup device comprising:
a holder; and
a hybrid-type blade movable with respect to the holder and integrally combining a first blade portion which supports and thermally insulates the objective lens and a second blade portion which supports and radiates heat from the driving coils, the first blade portion made of a reinforced plastic material and the second blade portion made of a metal having a higher thermal conductivity than the first blade portion;
wherein the second blade portion comprises a stepped protrusion and the first blade portion is combined to the second blade portion by enclosing the stepped protrusion within the first blade portion.
6. The optical pickup device of claim 5 , wherein the first and second blade portions are combined by molding the first blade portion onto the second blade portion.
7. An optical pickup device having an objective lens and driving coils, the optical pickup device comprising:
a holder; and
a hybrid-type blade movable with respect to the holder and integrally combining a first blade portion which supports and thermally insulates the objective lens and a second blade portion which supports and radiates heat from the driving coils, the first blade portion made of a reinforced plastic material and the second blade portion made of a metal having a higher thermal conductivity than the first blade portion;
wherein the second blade portion comprises a protrusion having a cross hole and the first blade portion is combined to the second blade portion by engaging the first blade portion in the cross hole.
8. The optical pickup device of claim 7 , wherein the first and second blade portions are combined by molding a portion of the first blade portion into the cross hole.