KR100427828B1 - Optical member and optical pickup using the optical member - Google Patents

Abstract

(Problem) The optical axes of the laser beams emitted from the light emitting members such as the two-wavelength laser diodes are made to coincide with each other in a simple configuration with respect to the laser beams parallel to each other.

(Solution means) As the optical member 30 in which the laser beams 13a 'and 13b' having different oscillation wavelengths enter their optical axes in parallel with each other, the incident surface 30a to which the respective laser beams 13a 'and 13b' are incident. ) And an emission surface 30b through which the laser beams 13a 'and 13b' incident on the incident surface 30a are emitted, and each laser beam 13a 'and 13b formed and incident on the incident surface 30a. The first diffraction grating 30f and the first diffraction grating are formed on the emission surface 30b and transmit the diffraction angles of the diffracted light diffracted by the respective laser beams 13a 'and 13b' according to the oscillation wavelength of '). A second diffraction grating 30g for diffracting each laser light 13a ', 13b' diffracted by 30f again at a diffraction angle in accordance with its oscillation wavelength, and emitted outward from the exit surface 30b. The optical axes of the diffracted light beams of the laser lights 13a 'and 13b' were made to coincide with each other.

Description

Optical member and optical pickup using same {OPTICAL MEMBER AND OPTICAL PICKUP USING THE OPTICAL MEMBER}

The present invention relates to an optical pickup capable of recording / reproducing for different optical discs such as CD (CD-R), DVD and the like and an optical member used for the optical pickup.

In recent years, as DVD devices for recording / reproducing DVD, which are optical discs having a higher recording density than CDs, have been commercialized and distributed, optical pickups mounted on the DVD devices have also been reduced in size and weight. In addition, since DVD devices are also required to be compatible with CD (including CD-R), two semiconductor lasers having different oscillation wavelengths of a laser light source for DVD (650 nm) and a laser light source for CD (780 nm). It is necessary to provide.

In addition, as a component of an optical pickup capable of reproducing various optical discs such as CD, CD-R, DVD, etc. in one optical disc device, two wavelengths having two light sources emitting laser light having different oscillation wavelengths into one case. It is known to use a laser diode. By using the two-wavelength laser diode, the optical system of the optical pickup can be simplified.

However, the optical axes of the laser light emitted from each light source of the two-wavelength laser diode are parallel to each other because the light sources are provided at different positions.

In order to use the two-wavelength laser diode in the optical pickup, it is necessary to coincide the optical axis of each laser light. As a technique for matching the optical axis emitted from such a 2-wavelength laser diode, it is described in Unexamined-Japanese-Patent No. 11-110785, Unexamined-Japanese-Patent No. 11-97804.

In the conventional semiconductor laser device, as shown in FIGS. 7 and 8, semiconductor laser elements 1 and 2 having different oscillation wavelengths are housed in a case 4, and a diffraction grating is disposed on an upper surface of the case 4. The configuration in which (3) is formed is shown.

The diffraction grating 3 transmits the laser light incident at an angle obliquely from the semiconductor laser element 1 as it is and exits, and simultaneously diffracts the laser light incident at the semiconductor laser element 2 at an oblique angle. Is designed to emit light in the same optical axis Ma direction. In this way, the apparent light emitting points 2A of the semiconductor laser devices 1 and 2 are the same optical axis or the same point (see Japanese Patent Laid-Open No. 11-110785).

Subsequently, another conventional two-wavelength laser diode package includes laser diodes 131, 132; 231, 232 of different wavelengths horizontally (vertical) disposed in the two-wavelength laser diodes 100; 200, as shown in Figs. 9A and 9B. It is shown that the optical axes of the laser beams emitted therefrom are in parallel.

Then, as shown in Fig. 10, the reflecting member 360, which is an external beam matching means (micro two-color prism, micro two-color plate, micro two-color beam splitter, etc.), is used, and the upper half of the reflecting member 360 Using the difference d between the slope 361 and the bottom reflective surface 362, the laser light incident on the reflecting member 360 is reflected at almost right angles and the optical axis of each of the reflected laser beams is matched ( See Japanese Patent Laid-Open No. 11-97804).

However, the conventional semiconductor laser device uses the diffraction grating 3, and in order to match the optical axis of each laser light, the laser light is emitted obliquely from the semiconductor laser elements 1 and 2, and is similarly applied to the diffraction grating 3. It has a structure inclined at an angle. For this reason, it is difficult to implement the positioning accuracy at the time of optical design or assembly of the two semiconductor laser elements 1 and 2.

On the other hand, the conventional two-wavelength laser diode package (100; 200) uses a reflecting member to match the optical axis of each laser light, each laser light emitted from the laser diodes (131, 132) is reflected at approximately right angles from the reflecting member Due to the deflection, the optical design is generally complicated, and it is very difficult to realize the positioning accuracy when assembling. In addition, it is necessary to arrange some optical members (collimer lens, objective lens, etc.) in the orthogonal direction, and thus there is a problem that the whole optical pickup becomes larger than the optical members arranged in a straight line.

In addition, since the transmission film or the reflection film corresponding to the laser light of the predetermined wavelength must be formed in the upper surface portion and the bottom portion of the reflection member, there is a problem that the formation of this film is expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical member and an optical pickup using the same, in which the optical axes emitted from a two-wavelength laser diode and the like coincide with each other in a simple configuration with respect to laser beams parallel to each other.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing for demonstrating the optical member and light emitting member which are one Embodiment of this invention.

2 is a schematic perspective view of the light emitting member in the optical pickup using the optical member which is one embodiment of the present invention.

FIG. 3A is a schematic explanatory diagram of an entrance face of an optical member which is one embodiment of the present invention, and FIG. 3B is a schematic explanatory diagram of an exit face of the optical member.

4 is a partial explanatory diagram for explaining the optical pickup using the optical member which is one embodiment of the present invention.

5 is a partially explanatory diagram for explaining a modification of the optical pickup using the optical member which is one embodiment of the present invention.

6 is a partially explanatory diagram for explaining an optical pickup using an optical member which is an embodiment of the present invention.

7 is a schematic configuration diagram of a semiconductor laser device using a conventional diffraction grating.

FIG. 8 is a schematic perspective view showing an appearance of the semiconductor laser device of FIG. 7.

9A and 9B are perspective views of another conventional laser diode package, respectively.

10 is a schematic explanatory diagram of another conventional laser diode package.

* Explanation of symbols on the main parts of the drawing

12: 2 wavelength laser diode 13a ': laser light (short wavelength laser light)

13b ': laser light (long wavelength laser light) 14: light receiving member

14a: light receiving element 30: optical member

30a: entrance face 30b: exit face

30f: first diffraction grating 30g: second diffraction grating

Means to solve the problem

As a first solution for solving at least one of the above problems, an optical member in which laser beams of different oscillation wavelengths are incident on their optical axes in parallel with each other, the incident surface on which each laser beam is incident, and the angle incident on the incident surface An emission surface having a laser light is emitted, and the diffraction angle of the diffracted light diffracted by the laser beams is transmitted according to the oscillation wavelength of each laser beam formed on the incident surface and transmitted, and the light is transmitted to the same position on the exit surface. A first diffraction grating for guiding the diffracted light and a second diffraction grating formed on the exit face and diffracted by the first diffraction grating for each laser light at a diffraction angle according to the oscillation wavelength, the outer side of the exit face The optical axes of the diffracted light beams of the laser beams emitted by are aligned with each other.

As a second solution, the optical member having the first diffraction grating and the second diffraction grating is integrally formed by resin molding.

As a third solution, the first diffraction grating and the second diffraction grating form a blade shape, and the blade direction of each diffraction grating is formed so as to be reverse to the incident laser beams.

As a fourth solution, the diffracted light of each laser light is the first diffracted light diffracted in the first diffraction grating and the second diffraction grating, respectively.

As a fifth solution, a two-wavelength laser diode having two light sources, each of which emits each laser light such that their optical axes are parallel to each other, and each laser light emitted from the two-wavelength laser diode is incident on the first diffraction grating of the incident surface. The optical lens, an objective lens diffracted at the first diffraction grating, and then diffracted at the second diffraction grating of the optical member, and an objective lens for condensing the diffracted light of each laser beam coincided with the optical axis and the diffracted light of each focused laser light Alternatively, the return light for each laser beam reflected by the optical disk of the CD is transmitted through the objective lens and the optical member and is incident on the light receiving member having the light receiving element.

Embodiment of the invention

An optical member and an optical pickup having the same according to one embodiment of the present invention will be described next with reference to FIGS. 1 to 6.

As shown in Figs. 1 and 6, the optical pickup includes a light emitting member, that is, a light receiving member 14 incorporating a two-wavelength laser diode 12, a light receiving element 14a, an optical member 30, and a collimator lens 40. ) And an objective lens not shown.

The optical pickup is arranged to face an optical disk (CD or DVD), not shown, so that the objective lens is movable in the focusing direction which is a direction orthogonal to the CD (DVD) plane and the tracking direction which is the radial direction of the CD (DVD). It is supposed to be.

As shown in Fig. 2, the two-wavelength laser diode 12 has a disk-shaped substrate portion 12a, a rectangular parallelepiped base 12b protruding from one side planar portion 12a 'of the substrate portion 12a, Laser body 13 positioned and fixed to the side wall surface (top surface in FIG. 2) of the base 12b, fixed to the one side planar portion 12a 'to contain the base 12b, and a cylindrical body portion Cap portion 12e integrally formed with ceiling plate 12d having 12c and opening 12d ', and a transparent disc-shaped optical glass plate fixed so as to block opening 12d' inside the cap 12e. 12f). In this way, the laser chip 13 is arrange | positioned in the sealed space in one package comprised from the board | substrate part 12a, the cap part 12e, and the optical glass plate 12f.

In addition, the optical glass plate 12f is perpendicular to the horizontal direction (y direction in FIG. 2) of the laser beams 13a 'and 13b' emitted and emitted from the light sources 13a and 13b described later (x in FIG. 2). Direction) to correct the difference in optical aberrations.

The laser chip 13 includes a light source 13a for emitting a DVD wavelength (650 nm band) laser light (13a '(indicated by a solid line in FIG. 1)) and a laser beam for a CD long wavelength band (780 nm band). The light source 13b which emits (13b ': shown with the dotted line in FIG. 1) is formed side by side (y direction in FIG. 2) at the adjacent position.

Moreover, the laser beams 13a 'and 13b' emitted from the light sources 13a and 13b respectively are parallel to each other in a direction orthogonal to the one side planar portion 12a 'of the substrate portion 12a (z direction in FIG. 2). It exits from the glass plate 12f so that it may lose.

In addition, the emission positions of the laser beams 13a 'and 13b' are configured on the same plane of the front end surface 13 '(arranged so as to be parallel to the planar portion 12a') of the laser chip 13. Further, a plurality of external connection terminals (not shown) are formed to protrude from the other planar portion on the opposite side to the one side planar portion 12a 'of the substrate portion 12a, and to the laser chip 13 via the external connection terminals. Driving current supply is performed.

Moreover, in the process of manufacturing the 2-wavelength laser diode 12, the laser chip 13 provided with the two light sources 13a and 13b is fine-processed like a semiconductor process on the predetermined board | substrate surface, Each light source 13a The space | interval D between and 13b) is formed uniformly at high precision with the predetermined | prescribed value which adjoins.

Subsequently, as shown in FIGS. 1 and 3A, 3B, the optical member 30 is made of a resin flat plate having an incidence surface 30a and an outgoing surface 30b facing each other. A first diffraction grating 30f having a sawtooth cross section is formed in the center portion of the 30a, and a second diffraction grating 30g having a sawtooth cross section is also formed at the center portion of the exit surface 30b. have.

As shown in Fig. 1, the optical member 30 is formed such that the first diffraction grating 30f and the second diffraction grating 30g form a blade (toothed) shape in a direction opposite to each other.

The first and second diffraction gratings 30f and 30g in the shape of the blade are diffracted so as to be emitted at a predetermined diffraction angle θ1 and θ2 when the laser beams 13a 'and 13b' in which the optical axes are parallel to each other are incident. The direction of the blade edges of the gratings 30f and 30g is formed by micromachining by resin molding so that the direction of the blade edges thereof is reverse to the incident laser beams 13a 'and 13b'.

Here, the first and second diffraction gratings 30f and 30g are integrally formed at the same time when the optical member 30 is formed by injection molding (resin molding).

The optical member 30 has the optical axes of the laser beams 13a 'and 13b' emitted from the two-wavelength laser diode 12 with respect to the incident surface 30a and the exit surface 30b, respectively. It arrange | positions so that it may enter or exit orthogonally with respect to 30a and the emission surface 30b.

Further, in the first and second diffraction gratings 30f, 30g, the primary diffraction light of each laser light 13a ', 13b' formed by these diffraction effects is different from the diffracted light (n = 2,3,4 ...). It is optically designed to increase the amount of light.

In addition, the optical member 30 is optimally optical so that optical aberration by each laser beam 13a ', 13b' is corrected when optically designing the thickness of the parallel flat plate or the shape of the first diffraction grating 30f. Design is made.

In the optical member 30, when the second diffraction grating 30g is optically designed, each of the laser beams 13a ', 13b' emitted from different incidence planes 30a to the emission plane 30g is formed. The optical aberration is corrected, and an optimal optical design is made so that these optical axes coincide and exit.

As shown in Fig. 4, the collimator lens 40 is made of a single lens made of resin or glass, and has a certain width to make incident laser light into parallel light.

And the collimator lens 40 is arrange | positioned so that it may be orthogonal to the optical axis of the laser beam radiate | emitted from the emission surface 30b with respect to the emission surface 30b of the said optical member 30. As shown in FIG.

That is, the optical axes of the laser beams 13a 'and 13b' emitted from the two-wavelength laser diode 12 and the diffracted light of the laser beams 13a 'and 13b' emitted from the emission surface 30b of the optical member 30. The optical axes are parallel to each other.

As shown in Fig. 6, the light receiving member 14 is composed of a package in which the light receiving element 14a is incorporated and an external connection terminal (not shown) protruding outward from the package.

And the light receiving member 14 is located in the space between the incident surface 30a of the optical member 30 and the two wavelength laser (except on the optical axis of the laser light 13a ', 13b'), and the optical disk ( Each return light from a DVD or CD)

In addition, the light receiving member 14 is capable of supplying a power supply voltage to the light receiving element 14a through an external connection terminal, or outputting a photoelectrically converted signal from the light receiving element 14a to the outside.

Next, the operation of the optical pickup will be described with reference to FIGS. 1 and 4.

First, the short wavelength laser light 13a 'emitted from the light source 13a of the two-wavelength laser diode 12 passes through the optical glass plate 12f and corrects the optical aberration resulting from the two-wavelength laser diode 12 to provide optical The first diffraction grating 30f of the incident surface 30a of the member 30 is incident.

The laser beam 13a 'passes through the first diffraction grating 30f by the diffraction action of the first diffraction grating 30f and then is dispersed in the nth order diffracted light.

Then, from the laser beam 13a ', n-th order light (n = 1, 2, 3…), such as a laser light (zero-order diffracted light) in a straight direction, not shown, and the first-order diffracted light adjacent thereto, are ordered. The primary diffracted light to be dispersed and formed, and to be used, is emitted at a predetermined diffraction angle [theta] 1.

And the primary diffracted light transmitted through the inside of the optical member 30 is guided toward the predetermined position P of the emission surface 30b.

Subsequently, the first diffracted light 13a 'incident on the second diffraction grating 30g of the optical member 30 at a predetermined incident angle θ3 is not shown again. ), It is dispersed by n-th order diffracted light having a predetermined diffraction angle (n = 1, 2, 3 ...) and emitted to the outside. Primary diffracted light is emitted from the exit surface 30b toward the collimator lens 40.

In this way, the short wavelength laser light 13a 'is emitted so that the optical axis becomes almost horizontal from the light source 13a to the first diffraction grating 30f of the optical member 30 (in the z direction in FIG. 1), The first diffraction grating is deflected from the first diffraction grating 30f to the second diffraction grating 30g at a predetermined diffraction angle θ1, and is again emitted from the second diffraction grating 30g to the collimator lens 40. This optical axis is set to be substantially horizontal (z direction in FIG. 1).

On the other hand, the long wavelength laser light 13b 'emitted from the light source 13b of the two-wavelength laser diode 12 transmits through the optical glass plate 12f and corrects the optical aberration resulting from the two-wavelength laser diode 12 to provide optical The first diffraction grating 30f of the incident surface 30a of the member 30 is incident.

The laser beam 13b 'passes through the first diffraction grating 30f by the diffraction action of the first diffraction grating 30f and is then dispersed into n-th order diffracted light, among which the first diffraction light (n = 1) ) Passes through the inside at a predetermined diffraction angle θ2 having an angle larger than the diffraction angle θ1, and is guided toward the predetermined position P of the emission surface 30b.

Subsequently, the first-order diffracted light incident on the predetermined position P of the emission surface 30b at the incident angle θ4, which is larger than the incident angle θ3, is dispersed at the second diffraction grating 30g again at a predetermined diffraction angle. Among them, the first diffracted light (n = 1) is emitted from the emission surface 30b toward the collimator lens 40.

In this way, the short wavelength laser light 13a 'and the long wavelength laser light 13b' emitted from the light sources 13a and 13b of the two-wavelength laser diode 12 to be parallel to each other are the first diffraction grating 30f. The first diffracted light of each laser beam 13a ', 13b' passing through the inside, but intersected at different points on the plane of the plane) is at the same position P of the second diffraction grating 30g of the exit plane 30b. The 2nd diffraction grating 30g is guided, and the optical axis of each laser beam 13a ', 13b' radiate | emitted exits so that it may mutually match.

Subsequently, each of the laser beams 13a 'and 13b', which are incident from the optical member 30 and exited from the collimator lens 40 toward the objective lens, not shown as parallel light, is focused by the objective lens. Small beam spots are formed on the recording information surface of the optical disc (CD, DVD, etc.) not shown.

As shown in FIG. 6, the return light reflected and returned from the recording information surface of the optical disk proceeds in the opposite direction (the arrow viewing direction shown in FIG. 6) while the objective lens, the collimator lens 40, and the optical member 30 ) Is sequentially transmitted to the light-receiving member 14 including the light-receiving element 14a, and is photoelectrically converted by the light-receiving element 14a to output a predetermined reproduction signal or the like.

Next, the modification of the optical member which is embodiment of this invention is demonstrated next according to FIG.

The optical member 30, which is a modification of the present invention, inclines the entrance face 30a and the exit face 30b of the optical member 30 slightly clockwise with respect to the y-axis direction shown in Fig. 5 (the inclination angle is?). It is characterized by.

Thus, the optical member 30 is inclined with respect to the optical axis of each laser beam 13a ', 13b' of the 2-wavelength laser diode 12, and the 1st-order diffraction of each incident laser beam 13a ', 13b' is carried out. Correction and adjustment of optical aberration (especially astigmatism) of the light can be easily performed, and the light amount of the first-order diffracted light used for a reproduction signal or the like is sufficient, so that the optical performance can be further improved.

The optical member 30 of the present embodiment described as described above allows the laser beams 13a 'and 13b' of different oscillation wavelengths to enter the optical axes in parallel with each other, and the respective laser lights 13a 'and 13b'. The incident surface 30a to be incident and the emission surface 30b to which each of the laser lights 13a 'and 13b' incident on the incident surface 30a is output, and formed and incident on the incident surface 30a. According to the oscillation wavelength of each laser light 13a ', 13b', the diffraction angles (theta 1, 2) of the diffracted light which diffracted each laser light 13a ', 13b' are made to transmit inside, and the exit surface 30b is transmitted. A first diffraction grating 30f for guiding the diffracted light at the same position P of the laser beam, and each laser light 13a ', 13b' formed on the emission surface 30b and diffracted by the first diffraction grating 30f. ) Is provided with a second diffraction grating 30g which diffracts again at the diffraction angle according to the oscillation wavelength, and diffracts the respective laser beams 13a ', 13b' emitted from the exit surface 30b to the outside. The optical axes were to match each other. Thereby, the laser light 13a ', 13b' emitted from each light source 13a, 13b of the 2-wavelength laser diode 12 does not need to be obliquely emitted as in the conventional example, so that the The design or the manufacture thereof can be simplified.

Moreover, since each laser beam 13a ', 13b' radiate | emitted from each light source 13a, 13b of the 2-wavelength laser diode 12 does not need to be comprised so that it may bend in an orthogonal direction using a conventional reflecting member, The design of the optical pickup using the optical member 30 can be simplified and the size can be easily reduced.

Further, the optical axis of the emitted laser light (diffraction light) does not have to be emitted at an angle from the second diffraction grating 30g of the emission surface 30b to each laser light 13a ', 13b' incident on the optical member 30. Can be matched with each other, so that the optical design becomes easy with a simple configuration.

Moreover, by integrally forming the optical member 30 provided with the 1st diffraction grating 30f and the 2nd diffraction grating 30g by resin molding, it can form easily in large quantities and can manufacture it inexpensively.

Further, by setting the first diffraction grating 30f and the second diffraction grating 30g in the same blade shape, each of the laser beams 13a ', 13b' and the second diffraction grating respectively incident on the first diffraction grating 30f are provided. At 30 g, the optical design for aligning the optical axes and emitting them as diffracted light becomes simple, and assembly is easy.

Further, the first and second diffraction gratings 30f and 30g form a blade shape, and the laser beams 13a 'and 13b' which enter the blade direction of each diffraction grating 30f and 30g into the incident surface 30a. The light amount of the diffracted light can be efficiently emitted from the emission surface 30b by being formed so as to be reverse to the direction of.

In addition, by forming the same blade shape, the mold for resin molding can be easily processed and produced, and the resin molding of the optical member can be easily processed.

In addition, by forming the same blade shape, simply forming the first and second diffraction gratings to be the target, so that the processing is simple, and at the time of mounting, the up and down direction of each of the first and second diffraction gratings (y-axis in the drawing) It is easy to assemble because care must be taken not to mount it incorrectly.

Further, since the diffracted light of each of the laser lights 13a 'and 13b' is the first diffracted light diffracted by the first diffraction grating 30f and the second diffraction grating 30g, the loss of light amount can be reduced further. It can be used efficiently.

In the optical pickup using the optical member 30 of the present embodiment, a two-wavelength laser having two light sources 13a and 13b that respectively emits laser beams 13a 'and 13b' so that their optical axes are parallel to each other. An optical member 30 and a second laser beam 13a ', 13b' emitted from the diode 12 and the two-wavelength laser diode 12 to be incident on the first diffraction grating 30f of the incident surface 30a; 1 to diffract the diffracted light of each laser light 13a ', 13b' which is diffracted at the first diffraction grating 30f and diffracted at the second diffraction grating 30g of the optical member 30 onto the optical disc of the DVD or CD. By returning each return light for each laser light reflected from the objective lens and the optical disk and coinciding with the optical axis, the objective lens and the optical member 30 are transmitted to the light receiving member 14 having the light receiving element 14a. Since each laser beam having the same optical axis is focused on each optical disc of the CD, In a simple configuration, the return light from the optical disk can be received accurately by the light receiving elements 14a of the same light receiving member 14.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It can change and implement within the range which does not deviate from the main meaning.

For example, the entrance face 30a and the exit face 30b of the optical member 30 may not necessarily be parallel flat plates.

In addition, the optical member 30 may be formed by integrally attaching the two-wavelength laser diode 12 and its case. Thereby, the process of positioning adjustment can be further simplified.

The optical member of the present invention described above is an optical member in which laser beams of different oscillation wavelengths are incident on the optical axis in parallel with each other, and an incident surface to which each laser beam is incident and each laser beam incident to the incident surface A light exiting surface having an exiting surface, and having different diffraction angles of diffracted light diffracted by the respective laser beams according to the oscillation wavelengths of the laser beams incident and incident on the incident surface; And a second diffraction grating for guiding the second diffraction grating formed on the exit face and diffracted by each of the laser beams diffracted by the first diffraction grating at a diffraction angle in accordance with the oscillation wavelength thereof. By making the optical axes of the diffracted light beams of the emitted laser beams coincide with each other, the laser light incident by using the conventional reflecting member is applied to the second diffraction grating on the exit surface. It is possible to match each other, the optical axis of the laser light (diffraction light) emitted at an angle does not need to be emitted can be a simple structure. In addition, this method is inexpensive as compared with the case of using a reflective member having a film formed in the related art.

In addition, since the optical member including the first diffraction grating and the second diffraction grating is integrally formed by resin molding, the optical member can be easily formed in large quantities, thereby making it inexpensive.

In addition, the first diffraction grating and the second diffraction grating form a blade shape, and by forming the blade direction of each diffraction grating so as to be reverse to the incident laser light, the amount of diffracted light can be efficiently emitted.

In addition, since the diffracted light of each laser beam is the first diffracted light diffracted by the first diffraction grating and the second diffraction grating, the amount of light of each laser beam dispersed in the first and second diffraction gratings can be efficiently used, thereby improving optical performance. It does not cause deterioration.

In addition, the optical pickup using the optical member of the present invention is a two-wavelength laser diode having two light sources that emit each laser light so that their optical axes are parallel to each other, the incident surface of the laser light emitted from the two-wavelength laser diode An optical member and an optical disk for condensing the diffracted light of each laser beam diffracted at the first diffraction grating and then diffracted at the second diffraction grating of the optical member onto an optical disc of a DVD or CD Since the return light for each laser beam reflected by the optical axis and coincided with the optical axis is transmitted through the objective lens and the optical member and is incident on the light receiving member having the light receiving element, the incident laser light does not have to be deflected in the orthogonal direction. Optical pickup using an optical member can be arranged in a straight line, making it easy to downsize and thin, and at the same time The pickup can be easily assembled and manufactured with good precision. In addition, since the laser beams having the same optical axis are condensed on the optical disc, the light returned from the optical disc can be accurately received by the light receiving element of the light receiving member with a simple configuration.

Claims (5)

As an optical member in which laser beams of different oscillation wavelengths enter their optical axes in parallel with each other, An incidence surface on which each of the laser beams is incident and an outgoing surface on which each laser beam incident on the incidence surface is emitted, A first diffraction formed through the incident surface and diffracting the diffracted light of the diffracted light diffracted by the respective laser beams according to the oscillation wavelength of the incident laser beam and transmitting the diffracted light to the same position of the exit face Lattice and A second diffraction grating formed on said exit surface and diffracted by said first diffraction grating by said first diffraction grating again at a diffraction angle in accordance with its oscillation wavelength, said each laser exiting from said exit plane to the outside An optical member, characterized in that the optical axes of diffracted light of light coincide with each other. The optical member according to claim 1, wherein the optical member including the first diffraction grating and the second diffraction grating is integrally formed by resin molding. The laser beam of claim 1 or 2, wherein the first diffraction grating and the second diffraction grating form a blade shape, and the blade direction of each diffraction grating is formed so as to be reverse to the incident laser beams. Optical member. The optical member according to claim 1 or 2, wherein the diffracted light of each laser beam is a first diffracted light diffracted by the first diffraction grating and the second diffraction grating, respectively. An optical pickup using the optical member according to claim 1 or 2, A two-wavelength laser diode having two light sources each emitting the laser light such that their optical axes are parallel to each other, The optical member for allowing the respective laser beams emitted from the two-wavelength laser diode to be incident on the first diffraction grating of the incident surface; An objective lens diffracted by the first diffraction grating and condensed by the second diffraction grating of the optical member and condensed diffracted light of the respective laser beams coincided with the emitted optical axis; Diffracted light of each focused laser light is reflected on an optical disc of a DVD or CD, and each returned light for each reflected laser light is transmitted to the objective lens and the optical member and is incident on a light receiving member having a light receiving element. Optical pickup characterized by.