JP2002150602A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device which makes a laser beam generated from two kinds of laser elements incident on an objective lens to read signals on a recording medium. SOLUTION: The optical pickup device is provided with an optical composite unit 1 provided with a first laser element 2 and a first light receiving part 3 which receives a laser beam emitted from the 1st laser element 2 and then reflected on a first recording medium in the same package, a second light receiving part 4 formed on the same semiconductor substrate on which the first light receiving part 3 in the optical composite unit 1 is formed and to receive the laser beam emitted from the second laser element 10 and then reflected on the second recording medium, and an optical element for optical path separation 5 disposed ahead of the optical composite unit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention selectively reads laser beams generated from two types of laser elements having different laser wavelengths into a single objective lens to read signals from two different types of recording media. The present invention relates to an optical pickup device.

[0002]

2. Description of the Related Art As an example of an optical pickup device, D
There are two types of laser elements, a first laser element that emits a laser beam capable of reproducing a VD disc and a recording and reproduction of a CD disc, and a second laser element that emits a laser beam having a wavelength suitable for high-density recording. In some cases, different types of recording media can be reproduced.

[0003] As such an optical pickup, an optical composite unit in which a photodetector suitable for a recording medium is usually arranged in the same housing for disc reproduction is used.

Incidentally, in the case of recording, the above-mentioned unit cannot cope with the point of emission intensity and heat generation. Therefore, a single laser is used, but in this case, it is necessary to separately provide a photodetector for receiving the laser, and the number of components increases and the configuration becomes complicated.

[0005]

A light beam emitted from a laser element having two wavelengths is a hologram detector for detecting reflected light from a recording medium. Since the hologram diffraction element and the light receiving element corresponding to the recording medium holograms are provided at the respective positions, there is a problem that the number of parts increases and the cost increases.

An object of the present invention is to provide an optical pickup device which solves such a problem.

[0007]

A first laser element and a first laser element are provided.
An optical combined unit including, in the same package, a first light receiving unit that receives a laser beam emitted from the laser element and reflected by the first recording medium; and a second laser that emits a laser beam corresponding to the second recording medium. A laser unit having an element and a second light receiving unit for receiving a laser beam emitted from the second laser element and reflected by the second recording medium are formed on the same semiconductor substrate in the optical composite unit; An optical path separating optical element is arranged in front of the composite unit, and the first light receiving section receives a laser beam from the first laser element reflected by the first recording medium by the optical path separating function of the optical path separating optical element, and The laser beam from the two-laser element is received by the second light-receiving unit.

[0008]

FIG. 1 is an optical arrangement diagram showing an optical system of an optical pickup device according to an embodiment of the present invention. The optical pickup device shown in FIG.
It is configured to be able to read VD signals.

In the figure, reference numeral 1 denotes a DV in the same package.
Laser element 2 that emits a laser beam corresponding to D
And a laser element 2 reflected by a disk
Is an optical composite unit including a first light receiving element 3 for receiving a laser beam corresponding to a DVD and a second light receiving element 4 for receiving a wavelength of a CD-R.

The optical composite unit 1 includes a laser element 2 that emits a laser beam having a wavelength suitable for DVD, for example, 650 nm, and a second light receiving element 4 corresponding to a CD-R.
The optical hologram diffraction element 5 for splitting an optical path is arranged in a front part of a package in which is installed. Reference numeral 6 denotes a beam splitter, 7 denotes a collimator lens for converting a parallel light laser beam, 8 denotes an objective lens for converging the laser beam, and 10 denotes a laser beam having a wavelength suitable for a CD-R for recording a CD, for example, 780 nm. This is a can type laser unit.

Reference numeral 11 is used for a CD-R. When writing information on a disc, the light intensity of a part of the laser beam emitted from the laser unit 10 and passing through the beam splitter 6 is measured, and the information is read. This is a monitor for determining the amount of laser output due to writing.

Next, an optical path for reproducing a DVD will be described. A laser beam emitted from the laser element 2 passes through a beam splitter 6 via a hologram diffraction element 5 and is irradiated on a collimator lens 7. The laser beam converted into parallel light by the collimator lens 7 is converged by the objective lens 8 and focused on a point a serving as a signal surface of the DVD disk 9.

The laser beam reflected by the disk 9 follows the same optical path, passes through the beam splitter 6 from the objective lens 8 via the collimator lens 7, is bent by the hologram diffraction element 5, and the radiation of the laser element 2 The first light receiving elements 3 arranged on different optical axes are irradiated.

Next, the optical path of CD writing (CD-R) will be described. The laser beam emitted from the laser unit 10 is applied to the beam splitter 6. After the optical axis is bent by the beam splitter 6, the beam is converged by the objective lens 8 having the same optical path as that for the DVD, and focused at the point b, which is the signal surface of the CD disk 9.

The laser beam reflected by the disk 9 is applied to an objective lens 8, passes through a beam splitter 6 via a collimator lens 7, is bent by a hologram diffraction element 5, and is converted into a second light receiving element corresponding to a CD-R. 4 is received.

The laser beam reflected from the disk 9 is applied to the hologram diffraction element 5 and received by the first light receiving element 3 and the second light receiving element 4, but the frequency of the light beam used for DVD is 650 nm and the CD is At the −R frequency of 780 nm, even if the hologram diffraction element 5 is the same, the diffraction rate is different, and the optical axis of the laser beam is bent, and the first light receiving element 3 corresponding to DVD and the second light receiving element corresponding to CD-R are used. The light is received by the element 4.

It is also conceivable to combine the laser unit 10 and the light receiving element in the same unit.
Since the R light emitting element has a large laser output and generates a large amount of heat and is affected by the light receiving element, a light emitting element having a good heat radiation effect is used and the laser unit is used alone.

A DVD is stored in the optical composite unit 1.
Is integrated with the first light receiving element 3 and the second light receiving element 4, but the laser beam emitted from the laser element 2 is used for reading a DVD, so the output of the laser beam is Because of the small number, the first light receiving element 3 and the second light receiving element 4 are less affected by heat generated by the laser element.

For this reason, the laser element 2, the first light receiving element 3, and the second light receiving element 4 can be provided on the same semiconductor substrate.

[0020]

According to the present invention, there is provided a second laser device for receiving a laser beam emitted from a second laser element of a laser unit.
Since the light receiving section is formed on the same semiconductor substrate of the optical composite unit in which the first laser element and the first light receiving section are provided in the same package, the same hologram diffraction element can be used in common, reducing the number of parts and assembling. An optical pickup having a simple configuration with a small number of steps can be provided.

Further, since a single laser unit is used for recording and reproduction, the problem due to heat generation can be solved by making this laser unit a can type.

[Brief description of the drawings]

FIG. 1 is an optical layout diagram showing an optical system of an optical pickup device according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 optical composite unit 2 laser element 3 first light receiving element 4 second light receiving element 5 hologram diffraction element 6 beam splitter 8 objective lens 9 disk 10 laser unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H049 AA02 AA12 AA25 AA57 AA65 CA15 CA20 5D119 AA04 AA41 BA01 CA09 DA01 DA05 EA02 EA03 EC45 EC47 FA05 FA08 JA14 KA02 LB07 5F073 AB06 AB21 AB27 BA05 FA02 FA06

Claims (2)

[Claims] 1. A laser beam emitted from each of a first laser element and a second laser element having a different laser wavelength is selectively incident on a single objective lens to form different types of first and second recording media. An optical pickup device for reading a signal, comprising: a first laser element and a first light receiving unit for receiving a laser beam emitted from the first laser element and reflected by a first recording medium in an optical package. A laser unit including a unit, a second laser element for emitting a laser beam corresponding to the second recording medium, and a laser unit for receiving a laser beam emitted from the second laser element and reflected by the second recording medium, and receiving the laser beam. A second light receiving unit formed on the same semiconductor substrate on which a first light receiving unit in the unit is formed; and a second light receiving unit disposed in front of the optical composite unit. Optical path separation optical element,
The first light receiving section receives the laser beam from the first laser element reflected by the first recording medium by the optical path separating function of the optical path separating optical element, and the second light receiving section receives the laser beam from the second laser element. An optical pickup device characterized in that light is received by the optical pickup device. 2. The method according to claim 1, wherein the first laser element is used for reproduction only,
The optical pickup device according to claim 1, wherein the laser element is used for recording and reproduction.