JP2000200440A - Light source unit and optical pickup device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce space necessary for adjusting the rotation of a light source unit. SOLUTION: In a light source unit 10, the plural beam P(n) of a lead frame 23 are protruded outside from the inside of a package 20. The protruding directions of these leads P(n) is the optical axial direction of a laser lean emitted from the light source unit 10. The leads P(n) are protruded only from the rear wall 213 of the package 20. Thus, when the light source unit 10 is rotated and adjusted around an optical axis, the necessity of securing extra space is eliminated to prevent the interference of the plural leads P(n) with other portions. Therefore, space necessary for adjusting the rotation of the light source unit is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source unit having a structure in which a laser light source and a photodetector are incorporated in a common package, and an optical pickup device having the light source unit mounted thereon.

[0002]

2. Description of the Related Art CD (Compact Disk), DVD
(Digital Video Disc) and other optical discs
An optical pickup device used for reproduction may use a light source unit having a configuration in which a semiconductor laser chip and a photodetector are incorporated in the same package.
A lead frame is mounted on the package of such a light source unit, and the light source unit is mounted on the optical pickup device by using the lead frame.

[0003]

When assembling the light source unit, the unit may be rotated around the optical axis to adjust the mounting position. For example, in a light source unit having a configuration in which a hologram element (diffraction element) for generating three beams is assembled in a package, the light source unit is rotated around the optical axis so that the three beams are focused on an appropriate position on a track of the optical disc. By rotating, the mounting position is adjusted. In this case, it is necessary that the external connection terminals protruding from the outer surface of the package do not hinder the rotation adjusting operation of the light source unit.

On the other hand, a semiconductor laser chip is built in a package of the light source unit. For this reason, heat generated by the semiconductor laser chip during driving may be trapped in the package, and the temperature inside the package may increase.
The rise in the temperature inside the package causes the operation of the semiconductor laser chip to be unstable. In particular, if a circuit for calculating and processing the detection result of the photodetector is incorporated in the package, the heat generated by this circuit is also added,
The temperature inside the package rises remarkably.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a light source unit which requires less space for rotation adjustment by devising a protruding direction of an external connection terminal of a lead frame.

Another object of the present invention is to provide a light source unit capable of suppressing heat generation inside a package.

Another object of the present invention is to provide an optical pickup device incorporating the novel light source unit.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for recording information on an optical recording medium by irradiating the optical recording medium with laser light and detecting return light from the optical recording medium. A light source unit used in an optical pickup device capable of reproducing information employs the following configuration.

That is, a laser light source, a light detecting element for receiving return light from an optical recording medium, a package containing the laser light source and the light detecting element, and a lead frame assembled in the package are provided. Have. The lead frame includes a plurality of external circuit connection terminals protruding outward from the package. These external circuit connection terminals protrude in a direction along the optical axis of the laser light emitted from the front surface of the package.

In the light source unit of the present invention, the plurality of external circuit connection terminals protrude in a direction parallel to the emission direction of the laser light emitted from the outer surface of the package. Therefore,
The rotation trajectory of the external circuit connection terminal when adjusting the rotation of the light source unit about the optical axis falls within the rotation trajectory of the outer surface of the package. Therefore, there is no need to secure a large space around the package.

Here, a configuration can be adopted in which the light receiving surface of the photodetector is parallel to the optical axis direction. Further, the outer surface of the package from which the plurality of external circuit connection terminals are taken out may be a rear surface of the package perpendicular to the emission direction.

A hologram element for separating laser light from a laser light source into three beams is assembled in an optical pickup device for detecting a tracking error of an objective lens by a three-beam method. The present invention is also applicable to a light source unit in which a diffraction element for separating laser light from such a semiconductor laser chip into a plurality of laser lights is mounted on a package.

[0013] Next, it is desirable that a heat radiation opening exposing a part of the lead frame to the outside is formed in the package of the light source unit. By providing such a heat radiation opening, heat generated during operation of a laser light source or the like can be efficiently emitted to the outside, and a rise in temperature inside the package can be suppressed. Therefore, the operation of the laser light source and the photodetector incorporated in the package can be stabilized. In addition, deterioration of those elements can be prevented. Thus, the output of the laser light source can be kept constant without increasing the amount of current supplied to the laser light source. Therefore, the power consumption of the optical pickup device can be reduced.

When a part of the lead frame exposed to the outside by the heat dissipation opening includes a ground wiring portion, the wiring portion and the outside are connected by a material having appropriate thermal conductivity as well as electrical conductivity. The contact may increase the heat radiation efficiency inside the package.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(Overall Configuration of Optical Pickup Device) FIG.
1A is a plan view of the optical pickup device 1 and FIG.
(B) and (C) are a sectional view and a side view in FIG. 1 (A). As shown in FIG. 1, the optical pickup device 1 performs recording or reproduction on an optical disk 4. The optical pickup device 1 includes a frame 9 arranged to face the optical disc 4, a light source unit 10 attached to the frame 9, and an objective lens 12 for condensing the laser light Lf emitted from the light source unit 10 on the optical disc 4. And an objective lens driving device 4 for driving the objective lens 12 in the focusing direction and the tracking direction.
0.

The frame 9 has a light source unit housing 10 penetrated in the thickness direction for housing the light source unit 10.
1 and an objective lens driving device storage section 401 that penetrates in the thickness direction to store the objective lens driving device 40. In each of the storage units 101 and 401,
The light source unit 10 and the objective lens driving device 40 are housed.

The objective lens driving device 40 includes the objective lens 1
2 is provided, and a support shaft 42 that supports the lens holder movably in the focusing direction and the tracking direction. The lens holder 43 has a cylindrical body 43. On the upper surface of the body portion 43, a lens holding portion 430 that protrudes thinly on the outer peripheral side is formed, and the objective lens 12 is held here. Torso 4
A shaft hole is formed in the center of 3, and a support shaft 42 is formed there.
Is plugged in.

A magnetic drive circuit for moving the lens holder 43 up and down along the support shaft 42 between the lens holder 43 and the frame 9 to correct a focusing error of the objective lens 12, In order to correct the tracking error, the lens holder 43 is
A tracking magnetic drive circuit for rotating around 2 is configured.

(Optical System of Optical Pickup Device) FIG. 2 is a diagram showing an optical system of the optical pickup device 1. In the optical pickup device 1, a first diffraction element 13, a second diffraction element 14, a reflection mirror 18, and an objective lens 12 are arranged in this order from the laser light source 2A toward the optical disk 4. Further, from the optical disc 4 to the light detecting element 3, the objective lens 12, the reflecting mirror 18, the second diffractive element 14, the first diffractive element 13, and the reflecting mirror 15 are arranged in this order.

Laser light is emitted from the semiconductor laser chip 2A back and forth. The forward laser light Lf emitted forward from the laser light source 2 is incident on the first diffraction element 13 almost perpendicularly. The first diffraction element 13 has a diffraction grating surface. This diffraction grating surface has a function of dividing the forward laser light Lf that has entered substantially perpendicularly into a main beam and two sub beams. In addition, the optical disc 4 has a function of converting the wavefronts of the two sub beams so that the two sub beams focus on the optical disc 4 before and after the optical axis. This diffraction grating surface is
It is formed at a position where it does not pass through the diffraction grating surface again when the return light Lr from enters the diffraction grating 13 again.

For this reason, the forward laser light Lf is split by the diffraction element 13 into a main beam and two sub beams. Of these beams, the main beam is used as laser light for signal reproduction, and the two sub-beams are used as laser light for tracking error detection.

The laser beam for signal reproduction and the two laser beams for tracking error detection are incident on the second diffraction element 14. The second diffraction element 14 has a maximum product of the zero-order diffraction efficiency in the optical path of the three laser beams reaching the optical disk 4 and the first-order diffraction efficiency in the optical path from the optical disk 4 to the photodetector 3. It is set to be. The diffraction grating surface formed on the second diffraction element 14 is substantially parallel to the diffraction grating surface of the first diffraction element 13.

Of the three laser beams, the second diffraction element 1
The light component (0th-order diffracted light) transmitted through the optical disk 4 is bent at a right angle by the reflection mirror 18 and then condensed on the track of the optical disk 4 via the objective lens 12. At this time, the laser beam for signal reproduction is focused on the track, and the two laser beams for tracking error detection are in a front focus state and a rear focus state.

The three laser beams converged on the recording surface of the optical disk 4 are reflected there and become return light Lr traveling from the optical disk 4 to the photodetector 3. These return lights Lr
Again enters the second diffraction element 14 of the light source unit 10 via the objective lens 12 and the rising mirror 18.

Here, the second diffraction element 14 has only a function of diffracting each return light in the width direction of the light source unit 10, and performs a wavefront conversion such as focusing and diverging on each return light Lr. No function. For this reason, the three return lights Lr incident on the second diffraction element 14 are diffracted by the diffraction action of the diffraction element 14 to change the traveling direction.

The light diffracted by the second diffraction element 14 is the first light.
Incident on the diffraction element 13. As described above, the diffraction grating surface of the first diffraction element 13 is not formed in a range where the diffracted light enters. Therefore, each diffracted light incident on the diffraction element 13 passes through the first diffraction element 13 and reaches the reflection mirror 15. These diffracted lights are raised by the reflection mirror 15 and irradiate the light receiving surface of the photodetector 3.

In this embodiment, an RF signal, a TE signal, and an FE signal are detected based on the amount of light incident on the light receiving surface of the light detecting element 3. These signals are supplied to the external circuit connection terminals P of the lead frame 23 provided in the light source unit 10.
(N) (n is an integer from 1 to 12) generated by a control device electrically connected to the control device.

The rear laser light Lb emitted from the laser light source 2A is used for feedback control of the laser light output of the semiconductor laser chip 2 via the monitoring light receiving element 25. This feedback control is also performed by the control device (not shown).

(Light Source Unit) Here, among the optical elements constituting the optical system of the optical pickup device 1, the laser light source 2A, the light detection element 3, the first and second diffraction elements 1
3, 14 and the reflection mirror 15 are a common package 2.
And is integrated as a light source unit 10.

FIGS. 3 and 4 show the light source unit. 3A is a plan view of the light source unit, and FIGS. 3B and 3C are a cross-sectional view taken along line AA ′ and a cross-sectional view taken along line BB ′ in FIG. 3A, respectively. . FIG. 4 is a front view of the light source unit. Note that FIG.
Now, to make the internal structure of the light source unit easier to understand,
A part of the package is omitted. In the following description, the width direction of the package is defined as the X direction, the vertical direction of the package is defined as the Y direction, and the front-rear direction of the package is defined as the Z direction.

As shown in these figures, the light source unit 1
The zero package 20 is formed of an insulating resin, and has a flat rectangular parallelepiped shape as a whole. Package 2
A cylindrical projection 201 is formed on the front surface 204 of the zero. A light passage hole 203 is formed by the cylindrical projection 201, and first and second diffraction elements 13 and 14 are attached before and after the light passage hole 203. Through these, the forward laser light Lf is
In addition, the return light Lr from the optical disc 4 is guided to the inside of the package 20 while being emitted from the inside to the outside.

The package 20 includes a package bottom plate 22
And a package cover plate 21 of an upside-down type covered on this bottom plate.
It is composed of The package bottom plate 22 and the package lid plate 21 define a chamber 202 in which the laser light source 2A and the like are mounted, and form a cylindrical projection 201.

The package cover plate 21 has a substantially rectangular upper wall 211, a front wall 212, a rear wall 213, and left and right side walls 214 which fall from four sides of the upper wall 211.
215. A part of the front wall 212 is cut in a concave shape, and a pair of left and right protruding side walls 21 is formed from both sides thereof.
6, 217 extend perpendicular to the front wall 212. The upper ends of these protruding side walls 216 and 217 are connected by a protruding upper wall 218 extending forward from the upper wall 211. By these protruding side walls 216, 217 and protruding upper wall 218,
A protruding portion 219 protruding forward is formed.

Here, the package lid 21 is a resin molded product molded with the lead frame 23 mounted in a molding die. That is, the lead frame 23 is assembled to the package lid plate 21.

The lead frame 23 is made of a 42 alloy (42
% Ni steel) or a copper alloy, and has a rectangular plate-shaped stage portion 231 and a plurality of, in this example, 12 leads (terminals for external circuit connection) P (protruding outside the package cover plate 21). n).

The lower surface of the upper wall 211 of the package cover plate 21 is a flat surface, which is a reference surface 30 for defining the position of the laser light source 2A and the like. Stage portions 231 are stacked on the reference surface 30.

External circuit connection leads P (1) to P (1)
2) extends rearward from the rear wall 213 of the package lid plate 21. In these leads P (1) to P (12), the pad portions to be wire-bonded are located on the left and right or behind the stage portion 231 on the substrate surface 30. An intermediate portion connecting the pad portion of each of the leads P (1) to P (12) and the portion protruding outward from the rear wall 213 is the side wall 214, 215 or the rear wall 2
13 buried.

(Configuration of Semiconductor Substrate and Its Peripheral Part)
FIG. 5 is an enlarged perspective view showing a semiconductor substrate and a peripheral portion thereof. As shown in this figure and FIG. 2A, the semiconductor substrate 11 is bonded to the stage portion 231 by an adhesive. On the substrate surface 111 of the semiconductor substrate 11, a substantially rectangular electrode portion 111a long in the front-rear direction is formed on one side in the width direction, and a signal processing circuit 26 is formed on the other side. The submount 24 is fixed to the electrode portion 111a with an adhesive. This submount 24 has a constant thickness,
A semiconductor laser chip 2 is fixed to the surface with an adhesive.

The semiconductor laser chip 2 receives the forward laser light L
front emission end face 2f from which f is emitted, and rear laser light Lb
And a rear emission end face 2b from which the light is emitted. From these emission end faces 2f, 2b, the respective laser beams Lf, Lb are emitted forward and backward, respectively, along a direction parallel to the substrate surface 111 of the first semiconductor substrate 11 (plate surface direction). . The emission point of the forward laser light Lf of the semiconductor laser chip 2 is located substantially at the center in the vertical direction of the package 20 on the forward emission end face 2f. The light is emitted to the outside through the first and second diffraction elements 13 and 14.

On the substrate surface 111 of the semiconductor substrate 11,
Signal processing circuit 2 formed on the side of electrode section 111a
Numeral 6 raises the level of the output signal of the signal detection element 3 so that an external control device can easily perform processing for generating a pit signal (RF signal), a tracking error signal (TE signal), and a focus error signal (FE signal). Circuit for The photodetector 3 is formed in front of the signal processing circuit 26.

The amount of light condensed on the light receiving surface of the light detecting element 3 is converted into an electric signal and supplied to the signal processing circuit 26. The signal processing circuit 26 amplifies an electric signal supplied from the light receiving surface of the photodetector 3 and converts the signal into a voltage corresponding to the amount of received light, and calculates a signal obtained by the I / V amplifier in a timely manner. It is composed of an arithmetic circuit unit and the like. The output of the signal processing circuit 26 is taken out from each electrode (not shown) formed on the substrate surface 111 of the semiconductor substrate 11 to the outside. Each electrode is electrically connected to the corresponding pad portion of the lead P (n) by wire bonding. Further, electrodes (not shown) formed on the semiconductor laser chip 2 and the submount 24 are also electrically connected to pad portions of predetermined leads P (n) by wire bonding. An output signal from each electrode is guided to an external control device via leads P (1) to P (12), and an RF signal, a TE signal, and an FE signal are generated.

Here, on the surface of the submount 24 corresponding to the rear position of the semiconductor laser chip 2, a monitoring detecting element 25 for feedback controlling the laser light output of the semiconductor laser chip 2 is formed. A part of the rear laser light Lb emitted from the rear emission end face 2b of the semiconductor laser chip 2 directly enters the monitoring detection element 25. The output signal of the element 25 is also the lead P
It is led to an external control device via (n). As a result, feedback control of the laser light output of the semiconductor laser chip 2 is performed.

As shown in FIG. 3, a mirror mounting portion 221 is integrally formed on the package bottom plate 22. The mirror mounting portion 221 is a projection having a trapezoidal cross section formed from almost directly below the signal detection element 3 to upward. The front surface of the trapezoidal mirror mounting portion 221 is a mirror mounting surface 222 inclined forward by 45 degrees, and the reflecting mirror 15 is fixed to the mirror mounting surface 222 with an adhesive or the like.

The return light Lr from the optical disk 4 which enters the package via the first and second diffraction elements 13 and 14 hits the reflection mirror 15 and is raised at a right angle by this mirror 15 to cause the light detection element 3 to move. Irradiate.

(External Shape of Package) Here, in order to accurately correct the tracking error of the objective lens 12, it is necessary to focus the main beam and the two sub beams at appropriate positions on the same track of the optical disk. is there. For this reason, when attaching the light source unit 10 to the frame 9, it is necessary to adjust the rotation of the light source unit 10 around the optical axis.

In the light source unit 10 of this embodiment, four arc-shaped reference curved surfaces 50a to 50d are formed on the outer peripheral surface of the cylindrical projection 201 of the package 20. These reference curved surfaces 50a to 50d are respectively formed on the protruding side walls 216 and 217.
And have the same central angle. Further, among these reference curved surfaces 50a to 50d, two reference curved surfaces 50a and 50c are line-symmetric with respect to the optical axis Lu, and the remaining two reference curved surfaces 50b and 50d are also line-symmetric with respect to the optical axis Lu.

Therefore, as shown in FIG. 1 (C), the rotation angle of the light source unit 10 is adjusted by using the reference curved surfaces 50a to 50d, whereby the sub-beam and the optical disk 4 for performing the tracking by the three-beam system are adjusted. Adjustment of the rotation angle with the truck can be easily performed.

Here, in the light source unit 10, the plurality of leads P (n) of the lead frame 23 are
Protruding from the rear wall 213. The direction in which the leads P (n) protrude is parallel to the optical axis direction Lu of the forward laser light Lf emitted from the package 20. Therefore, the rotation trajectory of the plurality of leads P (n) when rotating and adjusting the light source unit 10 around the optical axis is within the range of the rotation trajectory on the outer surface of the package. Therefore, there is no need to leave a space around the package for the lead P (n). As a result, the lead P
The width dimension of the optical pickup device 1 can be reduced as compared with the case where (n) protrudes from the side walls 214 and 215.
Therefore, the space for incorporating the light source unit 10 can be reduced, and if the light source unit 10 of this example is incorporated in the optical pickup device 1, the size of the optical pickup device 1 can be reduced.

FIG. 6 is a plan view of the light source unit 10. FIG. The package 20
In order to make the lead frame 23 easier to understand, the portion of the lead frame 23 is indicated by oblique lines. Package 2
0 upper wall 211 has three rectangular openings 70a, 70b
And 70c are formed. Of these openings,
From the opening 70a, the stage portion 2 of the lead frame 23
31 is partially exposed. A part of the stage portion 231 corresponds to a portion on which the laser light source 2A is mounted. Further, a part of the lead P (n) is exposed from the openings 70b and 70c.

In such a light source unit 20, the heat inside the package 20 is released to the outside through the openings 70a, 70b and 70c. In particular, since a part of the stage portion 231 on which the laser light source 2A is mounted is exposed to the outside, heat generated by the laser light source 2A can be efficiently emitted. Therefore, it is possible to suppress an increase in the temperature inside the package 20 due to heat generated during operation of the laser light source 2A, the signal processing circuit 26, and the like. Therefore, the operations of the laser light source 2A and the signal processing circuit 26 can be stabilized. Further, deterioration due to these heats can be prevented. When the heat generated by the laser light source 2A is large, it is necessary to increase the amount of current supplied to the laser light source 2A and keep the output of the light source 2A constant. However, in this example, it is not necessary to increase the amount of current supplied to the laser light source 2A, so that the power consumption of the optical pickup device can be reduced.

A part of the lead P (4) projecting from the opening 70a is a lead for ground wiring. The heat radiation efficiency of the lead frame 23 can be increased by directly contacting a part of the lead P (4) with the frame 9 or the like, or indirectly contacting with a wire such as aluminum or copper.

(Other Embodiments) In the optical pickup device 1, the diffraction element 13 for generating three beams is assembled into a package 20 and integrated as a light source unit 10. Instead, a light source unit without the diffraction element 13 may be used. Even with such a light source unit, it is possible to adjust the rotation. Therefore, by setting the projecting direction of the lead P (n) to the optical axis direction of the laser beam emitted from the unit, it is possible to incorporate the light source unit. Space can be reduced.

The optical pickup device 1 uses the first and second diffractive elements 13 and 14 which are independent from each other, but has one surface provided with the optical characteristics of the first diffractive element 13 and the other. Of course, a single optical element having the optical characteristics of the second diffraction element on the surface may be employed.

Further, the laser light source 2A is connected to the semiconductor substrate 11
Is mounted on the substrate surface 111, but the laser light source 2A is mounted on the stage portion 231 of the lead frame 23.
Or directly on the lead P (n).

Further, the optical system of the optical pickup device 1 includes not only the optical element shown in FIG.
a lens for converting f into a parallel light beam, a beam shaping prism for adjusting the light beam diameter in two orthogonal directions of the laser beam, an aperture limiting means for reading information of an optical disk of different specifications, a wavelength-selective optical element, and the like. An optical element may be included.

[0057]

As described above, in the light source unit of the present invention, a plurality of external circuit connection terminals are projected in a direction parallel to the optical axis direction of the laser light emitted from the package. For this reason, when rotating the light source unit about the optical axis, it is not necessary to secure a special space so that the plurality of external circuit connection terminals do not interfere with other components. Therefore, the space for assembling the light source unit can be reduced. Therefore, the size of the optical pickup device can be reduced by using the light source unit of the present invention also as the light source of the optical pickup device.

[Brief description of the drawings]

1A is a plan view showing an optical pickup device according to the present invention, FIG. 1B is a sectional view, and FIG. 1C is a side view.

FIG. 2 is a schematic configuration diagram of an optical system of an optical pickup device including a light source unit to which the present invention is applied.

FIG. 3A is a plan view showing a light source unit,
(B) is a cross-sectional view taken along line AA ′ of (A), and (C) is a cross-sectional view taken along line BB ′ of (A).

FIG. 4 is a front view of the light source unit shown in FIG.

FIG. 5 is an enlarged perspective view showing a peripheral portion of a laser light source in the light source unit shown in FIG. 3;

FIG. 6 is a plan view of the light source unit shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 optical pickup device 2A laser light source 2 semiconductor laser chip 3 signal detection element 4 optical disk 10 light source unit 11 semiconductor substrate 12 objective lens 13 first diffractive element 14 second diffractive element 15 reflection mirror 18 rising mirror 20 package 21 package lid Plate 22 Package bottom plate 23 Lead frame 24 Submount 26 Signal processing circuit 40 Objective lens driving device 50a, 50b, 50c, 50d Reference curved surface 70a, 70b, 70c Radiation opening 201 Cylindrical projection 203 Light passage hole 213 Package rear wall 231 Stage Part P (n) lead (terminal for external circuit connection)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Minoru Masawa 14-888 Ako, Komagane-shi, Nagano F-term in Sankyo Seiki Seisakusho Komagane Plant (reference) 5D119 AA01 AA38 EC39 FA05 FA22 FA28 FA31 FA33 JA03 KA28 MA09 NA04

Claims (6)

[Claims] 1. A light source unit used in an optical pickup device capable of reproducing or recording information recorded on an optical recording medium by irradiating a laser beam onto the optical recording medium and detecting return light from the optical recording medium. A laser light source, a light detection element for receiving return light from the optical recording medium, a package containing the laser light source and the light detection element, and a lead frame assembled to the package, The lead frame includes a plurality of external circuit connection terminals protruding outward from the package, and these external circuit connection terminals extend along an optical axis of laser light emitted from the front surface of the package. A light source unit that protrudes in a different direction. 2. The light source unit according to claim 1, wherein a light receiving surface of the photodetector is parallel to the optical axis direction. 3. The light source unit according to claim 1, wherein the plurality of external circuit connection terminals protrude from a rear surface of the package. 4. The package according to claim 1, wherein the package is provided with a diffraction element for separating laser light emitted from the laser light source into a plurality of laser lights. A light source unit characterized by the above-mentioned. 5. The package according to claim 1, wherein the package has a heat dissipation opening, and a part of the lead frame is exposed to the outside from the heat dissipation opening. A light source unit characterized by the above-mentioned. 6. An optical pickup device comprising the light source unit according to claim 1. Description: