JP2008305498A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device equipped with an optical element which can maintain the optical element in a stable state against the deformation of the optical element made of a resin material having optical anisotropy when it is mounted, and a large temperature change in an installation site, installation environments or the like after the installation. <P>SOLUTION: In an optical disk reader equipped with the optical pickup in which the optical element made of the resin material having optical anisotropy is adhesively fixed to a case, the optical element is of a quadrilateral shape, the phase difference optical axis 22A of the optical element is nearly parallel to the diagonal line of the quadrilateral, and the case and the optical element are adhesively fixed at two places in the counter angle part in the direction of the phase difference optical axis 22A of the optical element. Also, when adhesively fixing, the optical element is of a parallelogram shape for enabling to clearly judge the direction of the phase difference axis so as to prevent it from being adhesively fixed in the wrong direction. Furthermore, an adhesive used for adhesively fixing the optical element having a hardness of less than Shore D45 is used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup device that records and / or reproduces optical information on an optical disc (hereinafter referred to as recording and reproduction).

2. Description of the Related Art Conventionally, various types of optical pickup devices for performing optical recording / reproduction have been developed in optical disk reading devices for recording / reproducing optical disks such as CDs and DVDs. (For example, see Patent Document 1)
7 and 8 show the configuration of a conventional optical pickup 100. FIG.

In FIG. 7, the conventional optical pickup reads the optical information from the optical information recording medium, writes the optical information to the optical information recording medium, or an optical pickup having both functions. A λ wavelength plate 110 is affixed to the outer peripheral end face of the laser light transmitting portion provided in the laser, and as shown in FIG. It is directly bonded and fixed to the outer peripheral portion of the light transmitting open hole 102a (the outer peripheral end surface of the laser light transmitting open portion). By using such a configuration, an optical pickup having high performance and excellent mass productivity has been realized.
JP 2001-273664 A (Fig. 2-4)

  However, an optical element (for example, a quarter-wave plate) formed of a resin having optical anisotropy such as a wavelength plate in a conventional optical pickup device is bonded to the wall surface of a housing (for example, an opto base, a semiconductor laser, etc.). When fixing with an agent, physical deformation such as distortion or twist may occur due to shrinkage or adhesive force when the adhesive is cured, and coma, astigmatism, or spherical Various optical aberrations such as aberration may occur, and the recording / reproducing characteristics may be greatly deteriorated. In addition, for example, when used in a vehicle-mounted device, the ambient temperature may change greatly. In this case, the optical element cannot maintain a stable mounting state due to thermal modification or deterioration of the adhesive after curing, and the angle of the phase difference optical axis shifts, resulting in fluctuations in the polarization characteristics of the laser light. In addition, the recording / reproducing characteristics may be greatly deteriorated. For this reason, it is required to always secure a stable position and prevent deformation against a large temperature change.

  In this way, optical elements made of resin having optical anisotropy are factors that greatly affect recording / reproduction characteristics due to deformation during mounting and changes in the angle of the phase difference optical axis after mounting. It has become. For this reason, the optical element is fixedly attached to a predetermined position in a correct posture without physical deformation, and the position can be accurately maintained in a stable state against a large temperature change over a long period of time. Has become an important issue.

  The present invention has been made in view of the above circumstances, with respect to physical deformation when mounting an optical element formed of a resin having optical anisotropy, and a significant temperature change after mounting, Provided is an optical pickup device provided with the optical element capable of holding the optical element in a stable state, in other words, improving the shape reliability at the time of attachment and the position reliability after the attachment. For the purpose.

The present invention relates to an optical disk reading apparatus having an optical pickup in which an optical element made of a resin material having optical anisotropy is bonded and fixed to a housing, wherein the optical element has a quadrilateral shape, and the position of the optical element is The phase difference optical axis is substantially parallel to the diagonal line of the quadrilateral, and the casing and the optical element are bonded and fixed at two diagonal portions of the optical element in the phase difference optical axis direction.
Here, the resin material having optical anisotropy is a film-like plate made of a material such as polycarbonate or cycloolefin polymer, and has optical properties such as birefringence, and its thickness and level. By changing the direction of the phase difference optical axis, the polarization state and phase of the light transmitted through the film can be adjusted. By utilizing these optical characteristics, it is used for optical compensation of an optical disk reading device or a liquid crystal display.
The phase difference optical axis is a vector represented by a vector passing through the center of gravity of the optical element material in a vector along the fiber direction of the optical element material.
In the embodiment of the present invention, the diagonal portion in the phase difference optical axis direction is the phase difference light among the four corners of the optical element having a parallelogram shape as shown in FIG. It is two acute angle portions which are corner portions close to the axis.

  With this configuration, when the optical element is bonded and fixed to the housing, the stretching force generated in the optical element by the adhesive force of the adhesive is along the phase difference optical axis direction of the optical element, that is, the fiber direction. Occur. That is, since the stretching force can be concentrated in a direction strong against the load, physical deformation such as distortion and twist of the optical element can be suppressed, and deterioration of the optical characteristics can be reduced.

  In the present invention, the shape of the optical element is a parallelogram.

  With this configuration, when the optical element is bonded and fixed to the casing, the phase difference optical axis (fiber) direction of the optical element can be clearly determined, thereby preventing erroneous bonding and fixing. be able to.

  Furthermore, in the present invention, a material having a hardness of Shore D45 or less is used as an adhesive for bonding and fixing the optical element and the housing.

  Here, Shore D refers to the durometer type D hardness. For example, when the hardness is 50 degrees, it is generally expressed as D50.

  By having this configuration, physical deformation of the optical element caused by the stretching force of the adhesive can be suppressed, and optical aberration can be reduced.

  According to the present invention, after an optical element made of a resin material having optical anisotropy is mounted, the optical element is always in a stable state over a long period of time regardless of a change in installation place or environment. Can be held in. In other words, it is possible to provide an optical pickup device including an optical element that can improve the shape reliability at the time of attachment and the position reliability after the attachment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

An optical pickup device according to an embodiment of the present invention has a function of reading optical information from an optical information recording medium and / or writing optical information to an optical information recording medium, and has a function of protecting the semiconductor laser. A quarter wave plate is attached to an LD (semiconductor laser) block which is a body. This quarter-wave plate has a quadrilateral shape, and the phase difference optical axis has a fixed structure with an inclination of 45 degrees with respect to the polarization direction of the light emitted from the semiconductor laser. By having this configuration, light emitted from the semiconductor laser, which is linearly polarized light, is transmitted through the quarter-wave plate and converted to circularly polarized light, and the recording / reproducing accuracy for an optical disk such as a DVD or CD can be improved. It is.

  FIG. 1 shows an optical pickup device 1 of an optical disk reading device according to an embodiment of the present invention. This optical pickup device 1 is an opt base 2 that constitutes a casing portion, and is electromagnetic with respect to the opt base 2. And an objective lens actuator 3 connected to be displaceable using force. In FIG. 1, accurate description of the arrangement of the internal optical elements is complicated, and therefore the state when viewed from a plurality of directions is shown on the same plane for convenience.

Among these, the opt base 2 is provided with main optical systems excluding an objective lens 31 and a diaphragm portion, which will be described later, and includes a light source 21 using a semiconductor laser, a quarter-wave plate 22, a diffraction grating 23, and a forward path. For a light projecting optical system for projecting laser light from the semiconductor laser 21 onto the optical disc D, a half plate 24 that is a light beam separating means for separating the optical path between the light path and the return path, a collimating lens 25 that forms parallel light, and the like. The rising mirror 26 for changing the direction of the optical path and the optical path for the light receiving optical system reflected and returned by the optical disc D, and the light receiving optical system for the reflected light reflected by the optical disc D (after passing through the half plate 24) ) A reflection mirror 27 and an AS (Astigmatism) correction plate 28 arranged on the optical path, a light receiving element 29, and the like are arranged.
The diffraction grating 23 generates 0th-order light and ± first-order diffracted light for reading and servo. The half plate 24 reflects the laser beam incident from the semiconductor laser 21 side and bends the optical path by 90 degrees, and transmits the laser beam reflected by the optical disc D to separate the optical path of the light receiving optical system from the optical path of the light projecting optical system. It is like that. The AS correction plate 28 corrects the angle of astigmatism generated in the half plate 24 in order to perform good servo control in the tracking direction and the focus direction. In this embodiment, the direction of astigmatism Is rotated by 60 degrees with respect to the optical axis so as to have an angle of 45 degrees with respect to the dividing line provided on the light receiving surface of the light receiving element 29. The AS correction number 27 has a certain relationship between the thickness, the incident angle of the laser beam incident thereon, and the angle of the generated astigmatism (AS), and the optical path is calculated using this relational expression. The relational expression is omitted from the description. For the light receiving element 29, for example, a PIN photodiode is used as a photoelectric conversion element.

  On the other hand, the objective lens actuator 3 is provided with an objective lens 31 for condensing a laser beam onto a track (pit) of an optical disc D that records and reads information, a diaphragm unit (not shown), and the like. Although not shown, the objective lens actuator 30 of the present embodiment can be displaced in the radial (R) direction of the optical disk D to apply tracking servo, and is displaced in the thickness direction of the optical disk D to apply focusing servo. The movable part which can be provided, and the yoke part which supports this movable part are provided.

  With the above configuration, in tracking control, fine movement of the objective lens actuator 3 (objective lens 31) is performed by a servo mechanism (not shown) in order to cause the light beam from the semiconductor laser 21 to follow the track of the optical disk D. If a moving operation of a predetermined distance or more that cannot be followed by the servo mechanism is required, the opt base 2 is moved using a traverse mechanism (not shown).

  Next, the details of the LD (semiconductor laser) block 20, the semiconductor laser 21, and the quarter wavelength plate 22 of FIG. 1 will be described with reference to FIGS.

FIG. 2A is an external view of the optical base 2 with the LD block 20 attached thereto, and FIG. 2B is an enlarged sectional view thereof. Here, the LD block 20 is a housing formed of a metal plate or the like for fixing the semiconductor laser 21 and the quarter wavelength plate 22. Since it is necessary to adjust the position of the laser optical axis of the semiconductor laser 21 in the assembly process, a housing separate from other optical elements is prepared. That is, after the semiconductor laser 21 and the quarter wavelength plate 22 are bonded and fixed to the LD block 20 and the laser optical axis position of the semiconductor laser 21 is adjusted, the LD block 20 is bonded to the opto base 2 with the adhesive 41 and the adhesive 42. It is structured to be fixed with.

  Here, details of each of the above-described optical elements will be described.

  A semiconductor laser 21 that emits laser light having a predetermined wavelength for reading or writing on the optical disk D is used. Here, the semiconductor laser has a structure in which an active layer from which laser light is emitted exists in parallel to the upper surface of the semiconductor laser (the semiconductor laser upper surface 21A in the present embodiment). In addition, light emitted from the active layer has linearly polarized light in a direction parallel to the active layer. Therefore, when transmitted through an optical element (for example, a quarter wavelength plate) having optical anisotropy such that the phase difference optical axis forms +45 degrees or −45 degrees with respect to the polarization direction of the emitted light, Converted to circularly polarized light.

  3A is a diagram showing the shape of the quarter wavelength plate 22, FIG. 3B shows a state in which the quarter wavelength plate 22 is fixed to the LD block 20, and FIG. 2B is a front view. It is a top view of LD block when making it into a figure.

  The quarter wavelength plate 22 is an optical element formed of a resin having optical anisotropy. The quarter-wave plate has a quadrangular shape as shown in FIG. 3A, and in particular in the present embodiment, a parallelogram is used. The quarter-wave plate 22 has a structure in which the phase difference optical axis 22A forms 45 degrees with respect to the long side. Then, by attaching the long side of the quarter wavelength plate 22 in parallel with the upper surface 21A of the semiconductor laser 21, the polarization direction of the semiconductor laser and the polarization direction of the semiconductor laser 21 are set to 1/4 as described above. Since the inclination of the phase difference optical axis 22A of the wave plate 22 is 45 degrees, the emitted light of the semiconductor laser is converted from linearly polarized light to circularly polarized light when transmitted through the quarter wave plate 22.

As shown in FIG. 2 (b), the relationship between the opt base 2, the LD block 20, and the quarter wavelength plate 22 is such that the laser emission surface of the semiconductor laser 21 is perpendicular to the emission light of the semiconductor laser 21. 21B, the opto-base mounting surface 20A and the stepped surface 20C in the LD block 20 have a parallel structure, and the quarter-wave plate 22 is fixed on the stepped surface 20C. The upper surface 20F and the lower surface 20G surrounding the stepped surface 20C have a structure parallel to the upper surface 21A of the semiconductor laser 22. By attaching the quarter wavelength plate 22 with the upper surface 20F and the lower surface 20G as a reference, 1 / Two long sides of the four-wavelength plate 22 are parallel to the upper surface of the semiconductor laser 21 and can be appropriately positioned with respect to the center position of the quarter-wave plate 22 and the phase difference angle.
Further, a quarter-wave plate is attached to the stepped surface 20C, and an adhesive pool 20H that is recessed in a hemispherical shape toward the back of the paper surface is provided so as to fix the quarter-wave plate 22 with an adhesive. The shape can be fixed with.

As described above, the quarter-wave plate 22 that is a resin material having optical anisotropy is fixed to a housing such as the LD block 20 using an adhesive, and the quarter-wave plate 22 is fixed to four sides. As the shape, the four corners of the quadrangular shape are bonded and fixed at two locations which are two diagonal portions close to the phase difference optical axis 22A. In particular, for example, a film-like plate made of a material such as polycarbonate or cycloolefin polymer may be used as the quarter-wave plate, and these have optical properties such as birefringence, and have a thickness and retardation. Since the polarization state and phase of light transmitted through the film can be adjusted by changing the direction of the optical axis, these optical characteristics can be used. Here, the phase difference optical axis refers to an axis represented by a vector passing through the center of gravity of the optical element material in a vector along the fiber direction of the optical element. With such a configuration, when the quarter wavelength plate 22 is bonded and fixed to the housing, the expansion and contraction force generated in the quarter wavelength plate by the adhesive force of the adhesive is in the phase difference optical axis direction, that is, the fiber. Since it occurs along the direction, the stretching force can be concentrated in a direction strong against the load, physical deformation such as distortion and twist of the optical element can be suppressed, and deterioration of the optical characteristics can be reduced.

  Further, in the present embodiment, the quarter-wave plate 22 having a parallelogram shape is used as shown in FIG. That is, the quarter wavelength plate 22 is fixed to the LD block 20 at two acute angle portions that are close to the phase difference optical axis. Therefore, when the quarter wavelength plate 22 is bonded and fixed to a housing such as the LD block 20, the phase difference optical axis direction (fiber direction) of the quarter wavelength plate can be easily and clearly determined. Therefore, it is possible to prevent the quarter wavelength direction from being erroneously bonded and fixed.

  Next, a method for bonding and fixing the LD block 20 and the quarter-wave plate 22 will be described.

As described above, physical deformation such as distortion or twist may occur due to shrinkage or adhesive force when the adhesive of the quarter-wave plate 22 is cured. Various optical aberrations such as aberration, astigmatism, and spherical aberration are generated, and the recording / reproducing characteristics may be greatly deteriorated. For this reason, an adhesive specification with small optical aberration is preferred, and this optical aberration is generally preferably 20 mλ rms or less in terms of the wavefront aberration RMS value. Is known to be preferred. The wavefront aberration RMS value (hereinafter referred to as RMS value) is defined by the following formula 1.
RMS value = [{ΣH (ρ, θ) ² / N} − {ΣH (ρ, θ) / N} ² ] ^1/2 (Formula 1)
Where H (ρ, θ); shape function, ρ, θ; polar coordinates, N: number of data.

  Based on the above, the inventors set three levels for each of the four types of factors: the type of adhesive, the number of points to be bonded, the amount of adhesion, and the UV irradiation amount when curing the adhesive, using the experimental design method. The adhesive specifications were examined based on optical aberrations generated in the quarter-wave plate 22 that were assembled into nine types of adhesive patterns from that level and fixed with the adhesive patterns. Here, the level is an adhesion specification candidate for each factor, and 0.05 mg, 0.1 mg, and 0.2 mg were set for the adhesion amount level in this study.

FIG. 4 shows the experimental results in the above study. FIG. 4A shows the difference in aberration due to the difference in the material of the adhesive, FIG. 4B shows the difference in aberration due to the difference in the number of adhesion points of the adhesive, and FIG. 4C shows the quarter wavelength. The difference in aberration due to the difference in the amount of adhesion between the plate and the LD block 20, FIG. 4D shows the difference in aberration due to the difference in the UV irradiation amount when the adhesive is cured. Here, the process average is a value calculated based on the amount of aberration deterioration caused by each level, and the larger this value is, the smaller the amount of aberration deterioration is. For example, the process average χ _as of the astigmatism X _as generated due to the level j among the factors i is obtained by the following equation 2.

_m
χ _{as i, j} = 1 / m Σ {−10 log ₁₀ X _as ² _{i, j, k} } (Expression 2)
^{k = 1}
Where Xas: astigmatism of sample k (k = 1,... M) produced at level j among factors i, m: number of samples produced at level j among factors i. In addition, the process average regarding a coma aberration, a spherical aberration, and an RMS value can be calculated similarly.

Note that a curve a on the graph is a process average related to astigmatism, c is a process average related to commatic aberration, s is a process average related to spherical aberration, and r is a process average related to RMS value. is there.

As can be seen from the results in FIG. 4, with respect to the adhesion amount and the UV irradiation amount at the time of curing the adhesive, since the process average of the RMS value is close to 0, the adhesion amount is 0.05 mg and the UV irradiation amount is 3000 mJ / cm ^2. It is preferable that the RMS value is not significantly changed by 1 point or 2 points, but it is possible to determine that 2-point adhesion that can greatly improve astigmatism is preferable.

  Further, in the above examination, it has been found that the Shore hardness and the adhesion location of the adhesive are largely caused by optical aberration. Therefore, the following additional experiments were conducted with respect to these two specifications. In addition, in this additional experiment, in order to clarify the tendency of optical aberration deterioration, it was carried out at 0.10 mg which is twice the adhesion specification amount.

  First, with respect to the bonding location, the case of bonding and fixing at two diagonal portions in a substantially parallel direction with respect to the phase difference optical axis 22A (A) and the case of bonding and fixing at two vertical portions of the diagonal portion The comparative experiment (B) of the optical aberration generated in the above was performed. The results are shown in Table 1.

  As shown in Table 1, the optical aberration (astigmatism) that occurs in the quarter-wave plate when (A) is bonded and fixed at two diagonal portions of the optical element along the extending direction of the phase difference optical axis. As a result, it was confirmed that deterioration of aberration, coma aberration, spherical aberration, and RMS value can be reduced. Based on this result, the quarter-wave plate 22 is made a parallelogram so that the direction of the phase-difference optical axis 22A can be easily determined clearly. Bonding and fixing in the direction can be prevented.

Next, an experiment was conducted to confirm the relationship between the hardness of the adhesive and the wavefront aberration in the bonding and fixing of the quarter-wave plate 22. The result is shown in FIG. As can be seen from the graph of FIG. 5, when an adhesive having a hardness exceeding D45 is used, the optical aberration rapidly deteriorates and exceeds 10 mλrms. When the optical aberration deterioration is considered, optical aberration deterioration of 20 mλ rms or more may occur, and the optical characteristics of the entire optical pickup may be deteriorated. Therefore, when considering application to an in-vehicle environment, it can be determined that it is preferable to use a material having a hardness of at least D45.
Various reliability tests were performed using samples prepared based on the adhesion specifications determined based on the above. FIG. 6 shows fluctuations in the optical aberration of the quarter-wave plate in these various reliability tests.
Here, various reliability tests are tests that are performed assuming that they are mounted on in-vehicle electronic devices that are particularly susceptible to temperature changes. Thermal shock cycle test, high temperature and high humidity test, high temperature test, low temperature There are four types of standing tests. In each of the thermal shock cycle tests, the temperature at the place of installation is left at -40 ° C for 30 minutes, then the temperature is rapidly increased to + 85 ° C, left as it is for 30 minutes, and the temperature is further rapidly It was an environmental resistance test that lowered to −40 ° C., and this process was defined as one cycle, and 1000 cycles were performed. In the high-temperature and high-humidity storage test, an environmental resistance test was performed for 1000 hours in an environment where the temperature at the installation location was + 60 ° C. and the humidity was 90%. In the high temperature storage test, an environmental resistance test was performed for 1000 hours in the environment of the installation location temperature + 85 ° C. The low-temperature storage test is an environment resistance test that is performed in an environment where the temperature of the installation site is −40 ° C. for 1000 hours.
In FIG. 6, (A) is the result of the thermal shock cycle test, (B) is the result of the high temperature and high humidity leaving test,
(C) shows the result of the high temperature storage test, and (D) shows the result of the low temperature storage test.

  According to this experimental result, the optical aberration was about 5 mλrms before the reliability test, but no significant aberration deterioration was observed even after various reliability 1000 cyc and 1000 h had elapsed, and it was suppressed to 10 mλrms or less. In other words, it can be determined that the optical element made of a resin material having optical anisotropy is a reliable adhesive fixing method that is sufficiently applicable to an in-vehicle environment.

As described above, when the optical element is bonded and fixed to the casing, the optical element has a quadrilateral shape, and the phase difference optical axis of the optical element is substantially parallel to the diagonal of the quadrilateral, and the casing and the optical element Since the element is bonded and fixed at two positions of the diagonal portion of the optical element in the phase difference optical axis direction, when the optical element is bonded and fixed to the casing, the adhesive force of the adhesive causes the The stretching force generated in the optical element is generated along the phase difference optical axis direction of the optical element, that is, the fiber direction. That is, since the stretching force can be concentrated in a direction strong against the load, physical deformation such as distortion and twist of the optical element can be suppressed, and deterioration of the optical characteristics can be reduced.

  Furthermore, the shape of the optical element may be a parallelogram. In this case, when the optical element is bonded and fixed to the housing, the phase difference optical axis (fiber) direction of the optical element can be clearly determined. Fixing can be prevented.

  And, by using an adhesive that bonds and fixes the optical element and the housing with a hardness of Shore D45 or less, the physical deformation of the optical element caused by the stretching force of the adhesive is suppressed, Optical aberration can be reduced.

  In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can implement with a various form.

  The optical pickup device of the present invention can suppress deformation and positional change of an optical element made of a resin material having optical anisotropy against a large temperature change in an installation place or environment. In other words, it has the effect of improving the position reliability, and is particularly useful for an optical pickup device or the like that is mounted on an in-vehicle electronic device having a large temperature change.

The block diagram which shows the optical element of the optical pick-up apparatus which concerns on embodiment of this invention (A) External view showing an LD block fixed to an optical base of an optical pickup device according to an embodiment of the present invention (b) Diagram showing an LD block fixed to an optical base of an optical pickup device according to an embodiment of the present invention (A) Explanatory drawing which shows the quarter wavelength plate which concerns on embodiment of this invention (b) Explanatory drawing which shows the attachment to the LD block of the quarter wavelength plate which concerns on embodiment of this invention (A) Explanatory drawing which shows the process average comparison of each adhesive agent type | mold in examination of the adhesion specification of the quarter wavelength plate and LD block which concerns on embodiment of this invention (b) The quarter wavelength plate which concerns on embodiment of this invention (C) Process average comparison of each adhesion amount in quarter wave plate and LD block adhesion specification examination according to an embodiment of the present invention Explanatory drawing (d) Explanatory drawing which shows the process average comparison of each UV irradiation amount in the adhesion specification examination of the quarter wavelength plate and LD block which concern on embodiment of this invention The figure which shows the correlation of the hardness of the adhesive for a quarter wavelength plate and LD block which concerns on embodiment of this invention, and a wavefront aberration The figure which shows the fluctuation | variation of the optical aberration in various reliability of the quarter wavelength plate which concerns on embodiment of this invention. Configuration diagram showing an optical pickup device according to a conventional example External view of a semiconductor laser with a quarter-wave plate attached to a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pickup apparatus 2 Opt base 2A LD block mounting surface in opt base 3 Objective lens actuator 20 LD block (semiconductor laser block)
Opto-base mounting surface in 20A LD block 1/4 wavelength plate mounting surface (stepped surface) in 20C LD block
Wall top surface surrounding quarter wave plate mounting surface in 20F LD block Wall top surface surrounding quarter wave plate mounting surface in 20G LD block Adhesive pool for quarter wave plate mounting in 20H LD block 21 Semiconductor laser (light source) )
21A Upper surface of semiconductor laser 21B Laser exit surface of semiconductor laser 22 1/4 wavelength plate 22A Phase difference optical axis (fiber direction) of 1/4 wavelength plate
23 Diffraction grating 24 Half plate mirror (Flux separation means)
25 Collimating lens 26 Rising mirror 27 Reflecting mirror 28 AS correction plate 29 Light receiving element
31 Objective lens 41 Adhesive 1 for fixing LD block and opto base
42 Adhesive 2 for fixing LD block and opt base
43 Adhesive to fix quarter wave plate and LD block

Claims (3)

  In an optical pickup device in which an optical element made of a resin material having optical anisotropy is bonded and fixed to a casing, the optical element has a quadrilateral shape having an optical phase difference, and the casing and the optical element And an optical pickup device in which the two are bonded and fixed at two diagonal positions which are two angles close to the phase difference optical axis of the optical element.   The optical pickup device according to claim 1, wherein the optical element has a parallelogram shape.   The optical pickup device according to claim 1, wherein the hardness of an adhesive that bonds and fixes the optical element and the housing is Shore D45 or less.