JP2851863B2 - Optical disk driver and optical pickup - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A. Industrial application fields B. Summary of the invention C. Background art [Fig. 5] D. Problems to be solved by the invention E. Means to solve the problems F. Function G. Embodiment [ 1 to 4] H. Effects of the Invention (A. Industrial Application Field) The present invention provides an optical disk driver and an optical pickup, in particular, a laser beam emitted from a semiconductor laser is incident on a rotationally driven disk. The present invention relates to an optical disk driver and an optical pickup that detect return light and read information recorded on a disk.

(B. Summary of the Invention) The present invention relates to an optical disk driver or an optical pickup as described above, in which a semiconductor laser is exposed and arranged in the vicinity of the disk in order to increase the cooling effect while reducing the size, thickness, and cost. The semiconductor laser is forcibly cooled by a rotating wind pressure.

(C. Background Art) [Fig. 5] Conventionally, an optical disk driver used for signal reading in a compact display, a laser display, or the like, uses a diffraction grating to form three beams (one main beam and two sub beams). Beam), tracking is performed by a three-beam method, and focusing is performed by an astigmatism method using a cylindrical lens.

However, such a conventional optical disk driver is composed of a very large number of components such as a semiconductor laser, a diffraction grating, a beam splitter, an objective lens, a cylindrical lens, and a light receiving element. Since the above optical components must be assembled so as to have a predetermined positional relationship and adjusted with very high precision, the cost of assembling and adjusting the optical components has also become very high. Further, the large number of optical components constituting the optical disk driver inevitably restricted the miniaturization of the optical disk driver, and further prevented the miniaturization of compact disk players and video display players.

Therefore, the applicant company of the present application provides each photodiode for signal reading, error detection for tracking servo and focus servo on one part of one semiconductor substrate, and mounts a semiconductor laser on another part of the semiconductor substrate. An optical disk driver having a mounting structure and a prism bonded to a portion of the semiconductor substrate on which the photodiode is formed has been developed. This optical disk driver reflects a laser beam emitted from a semiconductor laser on a reflecting surface formed on the optical disk driver side of a prism, condenses the light with a lens, enters the disk, and returns the reflected light reflected by the disk as described above. A prism is used to guide the diode to the semiconductor substrate, which enables a drastic reduction in size, thickness, and cost.
Based on the results of this development, the applicant has already filed Japanese Patent Application Nos. 61-38576, 61-126318 and 61-3.
Many proposals were made by 8575 mag.

By the way, the applicant of the present invention specifically tried to implement the above-mentioned optical disk driver in the mode as shown in FIG.

a is a ceramic package, b is a silicon semiconductor substrate mounted on the bottom surface of the ceramic package a, and a photodiode for information reading, tracking error detection and focusing error detection is provided on a part of the surface of the semiconductor substrate b. Is formed. c is a semiconductor laser chip mounted on a portion of the semiconductor substrate b where no photodiode is formed, d is a prism mounted on a portion of the semiconductor substrate b where the photodiode is formed, and e is a ceramic package a. It is a transparent plate that stops.

f is an integrated component substrate, and g is a flexible wiring board adhered to the integrated component substrate f so as to extend therefrom. The electronic circuit in the semiconductor substrate b provided in the ceramic package a and the semiconductor laser chip c are connected to the outside. Electrical connection between them.

The ceramic package a is fixed to the back surface of the integrated component substrate f (the surface on the side opposite to the flexible wiring board) with its outer bottom surface facing downward. A holding member h holds the ceramic package a fixed to the integrated component substrate f, and a lens and a mirror described later. Reference numeral i denotes a mirror held by a holding member h, which reflects the laser beam emitted from the semiconductor laser chip c and directed downward by being reflected from the inclined surface of the prism d at right angles to lateral light. j
The mirror held by the holding member f also reflects the horizontal laser beam reflected by the mirror i to generate upward light. Reference numeral k denotes a lens held by a holding member h, which focuses the laser beam from the mirror j and irradiates the laser beam on the information recording surface of the disk l. m denotes a focus control coil attached to the holding member h so as to surround the holding member h. When a focus driving current obtained by amplifying a focus error detection signal is supplied, the holding member h including the lens k is turned on. Moves in the axial direction to eliminate focus errors. still,
There are tracking control coils to eliminate tracking errors, but they do not appear in the drawing. n is a case for storing the holding member h, each coil and the like.

In the optical disk driver shown in FIG. 5, a ceramic package a containing a semiconductor laser chip c and the like is mounted on an integrated component substrate f, and the integrated component substrate f is covered by a case n.

(D. Problems to be Solved by the Invention) By the way, the optical disk driver shown in FIG. 5 can be reduced in size, thickness, and cost, but it is difficult to obtain sufficient heat dissipation. Have. This is because the intensity of the laser beam output from the semiconductor laser chip c must be more than a certain level in order to normally operate as an optical pickup even if the optical disk driver is reduced in size and thickness. However, there is a limit to reducing the power of the semiconductor laser. Therefore, it becomes more difficult to obtain necessary heat dissipation as the optical disk driver becomes smaller and thinner. In addition, the semiconductor laser chip c
Is separated from the outside by the integrated component substrate f and the case n, so that there is no heat dissipation path for effective heat dissipation. Therefore, it is difficult to obtain sufficient heat dissipation.

The use of a TH (Thermo-electric) cooler, cooling fan, or heat pipe solves the problem of insufficient heat dissipation, but on the other hand, the optical disk driver is smaller, thinner, and less expensive. Can not be adopted because it is blocked.

The present invention has been made to solve such a problem, and an object of the present invention is to increase the cooling effect while reducing the size, thickness, and cost of an optical disk driver or an optical pickup.

(E. Means for Solving the Problems) In order to solve the above problems, the optical disk driver of the present invention focuses a semiconductor laser constituting an optical pickup and light from the semiconductor laser on the surface of a rotationally driven disk. An optical disk driver, comprising: a lens provided in at least one case; and an opening indispensable for transmitting light from the semiconductor laser on one surface facing the disk surface of the case, wherein the semiconductor laser is provided with a heat radiation. The case is provided in the case such that the surface faces the disk through an opening provided in the surface of the case on the disk side, and the semiconductor laser receives a rotating wind pressure of the disk.

In order to solve the above-mentioned problems, an optical disk driver according to the present invention includes a semiconductor laser, a lens that focuses light from the semiconductor laser toward a rotationally driven recording medium, and a supporting unit that movably supports the lens. Comprising, the semiconductor laser, the lens and the support means provided in one case,
An optical pickup provided with an opening for emitting light from the semiconductor laser toward the recording medium through the lens on a surface of the case facing the recording medium, wherein the semiconductor laser has a heat radiation surface. Is disposed in the case so as to face the recording medium through an opening provided in the case.

(F. Function) According to the optical disk driver or the optical pickup of the present invention, since the semiconductor laser is exposed to the outside, the heat dissipation is enhanced. In addition, since the semiconductor laser is forcibly cooled, the semiconductor laser can be forcibly cooled by the rotating wind pressure of the disk without providing a special cooling means such as a TH cooler. Therefore, the heat generated by the semiconductor laser can be effectively dissipated so that the temperature of the semiconductor laser does not become higher than the allowable temperature.

(G. Embodiment) [FIGS. 1 to 4] Hereinafter, an optical disk driver or an optical pickup according to the present invention will be described in detail with reference to illustrated embodiments.

1 to 4 show one embodiment of the present invention, and FIG. 1 is a perspective view showing the appearance.

In the drawings, reference numeral 1 denotes a case, and a main part of the present optical disk driver (or optical pickup) is housed in the case 1. Reference numeral 2 denotes an opening formed on the upper surface of the case 1. The opening 2 has an objective lens 3 having a finite magnification.
And a bottom surface of a ceramic package 4 for accommodating a semiconductor laser chip, a photodiode and the like, which will be described later.

Reference numeral 5 denotes a base for supporting the case 1 containing the main part of the optical disk driver (or the optical pickup) on the upper surface.
The optical disk is guided in the horizontal direction by guide members 6 and 7, and is moved in the radial direction of the optical disk by driving means having a pinion (not shown) which engages with the rack 8.

FIG. 2 is a perspective view showing what is stored in the case 1,
FIG. 3 is an exploded perspective view showing what is stored in the case 1.

9 is a magnetic yoke member which also serves as a support frame, 10
Reference numerals a and 10b denote a pair of opposing portions of the magnetic yoke member 9, and the opposing portions 10a and 10b have plate-like pieces 11a and 11b bent inwardly from the lower portion thereof to face each other in parallel.

Reference numerals 12a and 12b denote magnets fixed to the inner surfaces of the opposing portions 10a and 10b. The magnets 12a and 12b and the magnetic yoke member 9 form a magnetic field required for focusing and tracking.

Reference numeral 13 denotes an optical system component including the objective lens 3 (mostly housed in the ceramic package 4).
Is held movably in the X direction (radial direction of the optical disk) and the Z direction (vertical direction) by the magnetic yoke member 9 via movable support members 14a and 14b. That is, the cut parts 15a, 15b are provided inside the magnetic yoke member 9.
A pair of movable support members 14a, 14b are attached by engagement, and the movable support members 14a, 14b move in the Z direction with hinges 16a, 16a, 16b, 16b that allow movement in the X direction. Allowable hinges 17a, 17a, 17a, 17a, 17b, 1
7b, 17b, and 17b. Then, the movable support member 14
The holding member 13 is attached to the a and b via the notch portions 18a and 18b by engagement. Therefore, the holding member 13 is held by the magnetic yoke member 9 so as to be movable in the X direction and the Z direction.

FIG. 4 is a sectional view showing the optical system held by the holding member 13. As shown in FIG.

Reference numeral 19 denotes a silicon semiconductor substrate mounted on the inner bottom surface of the ceramic package 4, and a plurality of photodiodes required for performing tracking error detection, focus error detection, and signal reading are formed in a partial area. Reference numeral 20 denotes a semiconductor laser chip provided on the photodiode forming region of the semiconductor substrate 19 via the support 21, and reference numeral 22 denotes a prism disposed on the photodiode forming region of the semiconductor substrate 19. The semiconductor laser chip 20 may be directly bonded to the semiconductor substrate 19.

The ceramic package 4 containing the semiconductor laser chip 20 and the like has the holding member 13 together with the lens 3 with the outer bottom surface facing upward.
It is attached to the upper part so that it is exposed to the outside. Since the bottom surface of the lens 3 and the ceramic package 4 faces the opening 2 of the case 1 as described above, the bottom surface of the ceramic package 4 is exposed to the outside. The present optical disk driver (or optical pickup) is greatly different from the conventional one shown in FIG. 5 in that the bottom surface of the ceramic package 4 is exposed to the outside under the optical disk.

Reference numeral 23 denotes a flexible wiring board connected to the upper surface of the ceramic package 4 (however, it is turned upside down in this embodiment because it is mounted upside down).
The electrical connection between the internal electronic circuit and the external circuit is made. In this embodiment, the flexible wiring board 23 also serves to seal the inside of the ceramic package 4.
A sealing may be performed by using a transparent sealing plate separately from 23.

24 is a prism emitted from the semiconductor laser chip 20
A mirror for reflecting the downward laser beam reflected by the optical surface 22 to be oriented in a horizontal direction;
A mirror that reflects the laser beam from
The laser beam reflected by the mirror 25 is focused and irradiated by the objective lens 3 onto the recording surface of an optical disk 26 as a recording medium.

Reference numeral 27 denotes a drive coil unit (see FIGS. 2 and 3), a focus control coil 28 wound in a rectangular frame shape, and tracking control attached to both ends of a pair of opposing sides of the focus control coil 28. It consists of coils 29, 29, 29, 29. The drive coil unit 27 includes tracking control coils 29, 29, 2
The opposite sides having the magnets 9 and 29 are the magnets 12a and 12a of the magnetic yoke member 9.
b, and is attached to the holding member 13 such that the remaining opposing sides are located on a pair of outer surfaces of the holding member 13.

Then, when a current corresponding to the tracking error signal is supplied to the tracking control coil 29, an electromagnetic force for moving the holding member 13 in the X direction acts accordingly, thereby eliminating a tracking error. Further, when a current corresponding to the focus error signal is supplied to the focus control coil 28, an electromagnetic force for moving the holding member 13 in the Z direction acts accordingly to eliminate a focus error.

The details of the principle of the optical pickup, such as the principle of detecting a focus error and the principle of detecting a tracking error, are described in Japanese Patent Application No.
38576, Japanese Patent Application No. 61-126318, and Japanese Patent Application No. 61-38575 have already been described with reference to the specification, drawings, etc., and will not be described here.

In the present optical disk driver (or optical pickup), a ceramic package 4 containing a semiconductor laser chip 20 as a heat source is exposed to the outside with its outer bottom face upward. Therefore, when the optical disk 26 is rotated, the ceramic package 4 is forcibly cooled by the rotational wind pressure of the disk. Therefore, heat generated from the semiconductor laser chip 20 can be effectively dissipated without providing a special cooling means such as a TH cooler.

Various modifications may be made to the present invention, for example, a heat sink plate made of a metal such as aluminum may be fixed to the outer bottom surface of the ceramic package 4 to reduce the thermal resistance of the heat radiation path. .

The present invention is applicable to various optical disk drivers or optical pickups such as a video disk player, a compact disk player, a magneto-optical recording driver, and a direct read-after-write device.

(H. Effects of the Invention) As described above, the optical disk driver of the present invention
A semiconductor laser constituting an optical pickup, and a lens for focusing light from the semiconductor laser on a disk surface driven to rotate is provided in at least one case, and the semiconductor laser is provided on one surface of the case facing the disk surface. An optical disk driver provided with an opening for transmitting light from the case, wherein the semiconductor laser is inserted into the case such that a heat radiation surface of the semiconductor laser faces the disk through an opening provided on a surface of the case on the disk side. Wherein the semiconductor laser receives a rotating wind pressure of a disk.

Therefore, according to the optical disk driver of the present invention, since the semiconductor laser is exposed to the outside through the opening of the case, heat dissipation is improved. In addition, since the semiconductor laser is forcibly cooled, the semiconductor laser can be forcibly cooled by the rotating wind pressure of the disk without providing a special cooling means such as a TH cooler. Therefore, the heat generated by the semiconductor laser can be effectively dissipated so that the temperature of the semiconductor laser does not become higher than the allowable temperature.

Further, the optical pickup of the present invention comprises a semiconductor laser, a lens for focusing light from the semiconductor laser toward a recording medium which is rotationally driven, and a supporting means for movably supporting the lens. , A lens and a supporting means provided in one case, and a light having an opening for emitting light from the semiconductor laser toward the recording medium through the lens on a surface of the case facing the recording medium. A pickup, wherein the semiconductor laser is disposed in the case such that a heat radiation surface thereof faces the recording medium through an opening provided in the case.

Therefore, according to the optical pickup of the present invention, since the semiconductor laser is exposed to the outside through the opening of the case, heat dissipation is improved. In addition, since the semiconductor laser is forcibly cooled, the semiconductor laser can be forcibly cooled by the rotating wind pressure of the recording medium without providing a special cooling means such as a TH cooler. Therefore, the heat generated by the semiconductor laser can be effectively dissipated so that the temperature of the semiconductor laser does not become higher than the allowable temperature.

[Brief description of the drawings]

1 to 4 are views for explaining one embodiment of the present invention, wherein FIG. 1 is a perspective view showing an external appearance, FIG. 2 is a perspective view showing one housed inside a case, FIG. FIG. 3 is an exploded perspective view of what is housed inside the case, FIG. 4 is a cross-sectional view showing a main part, and FIG. 5 is a cross-sectional view showing a conventional example. Reference numerals 4, 20... Semiconductor laser, 26... Disk (recording medium).

Claims (2)

(57) [Claims] A semiconductor laser constituting an optical pickup and a lens for focusing light from the semiconductor laser on a disk surface driven to rotate are provided in at least one case, and one lens facing the disk surface of the case is provided. An optical disk driver provided with an opening for transmitting light from the semiconductor laser on a surface thereof, wherein the heat radiation surface of the semiconductor laser faces the disk through an opening provided on the disk side surface of the case. An optical disk driver provided in the case so that the semiconductor laser receives a rotating wind pressure of the disk. 2. A semiconductor laser, and a lens for focusing light from the semiconductor laser toward a rotationally driven recording medium;
Supporting means for movably supporting the lens, the semiconductor laser, the lens and the supporting means are provided in one case, and the light from the semiconductor laser is applied to the lens on a surface of the case facing the recording medium. An optical pickup provided with an opening for emitting light toward the recording medium through the case, wherein the semiconductor laser is disposed in the case such that a heat radiation surface of the semiconductor laser faces the recording medium through an opening provided in the case. Optical pickup characterized by being arranged in