JP4699224B2 - Optical pickup device - Google Patents

Description

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

  Conventionally, various optical pickup devices have been developed to perform optical recording and reproduction on optical disks such as CDs and DVDs. This optical pickup device uses an objective lens to project light from a light source onto an optical disc and guides reflected light from the optical disc to a light receiving element to read various information recorded on the optical disc. There is known a method of separating a light path between a light projecting optical system and a light receiving optical system by providing a light beam separating means (for example, a beam splitter or a half plate mirror) between the light receiving element and the light receiving element (for example, see Patent Document 1). .

That is, as shown in FIG. 9, this optical pickup apparatus is provided with a light beam separating means such as a half plate mirror (hereinafter abbreviated as “half plate”) 102 in the middle of the optical path from the light source 101 to the optical disk D. It is. In the figure, reference numeral 103 denotes a collimating lens, 104 denotes a rising mirror, 105 denotes an objective lens, 106 denotes a parallel plate, and 107 denotes a light receiving element.
JP 2002-123969 A

  By the way, in the conventional optical pickup device, when the light beam separating means is fixed to the floor surface of the housing (for example, opt base) with an appropriate adhesive or the like, the shrinkage or adhesive force when the adhesive is cured, etc. May cause physical deformation such as distortion and torsion, and with this deformation, various aberrations such as coma, astigmatism, and spherical aberration may occur, and the recording / reproduction characteristics may be greatly deteriorated. There is. For example, when used in a vehicle-mounted device, the ambient environmental temperature changes greatly. In this case, the light beam separating means cannot maintain a stable mounting state due to thermal modification or deterioration of the adhesive after curing, and the position of the light beam separating means is shifted, resulting in a light condensing position in the light receiving optical system. Since the fluctuation is caused, 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 particular, for the light beam separation means of the optical pickup device mounted on the in-vehicle optical disc recording / reproducing apparatus, it is required to maintain a more accurate mounting state for a long period of time.

  As described above, in the light beam separation means, deformation at the time of attachment, change in position after attachment, and the like are factors that greatly affect recording / reproduction characteristics and the like. For this reason, the light beam separation means 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, and is a state in which the light beam separating unit is stable with respect to physical deformation at the time of mounting the light beam separating unit and a large temperature change after the light beam separating unit is mounted. In addition, an optical pickup device provided with a light beam separating means that can be maintained with high positioning accuracy, in other words, can greatly improve the shape reliability at the time of mounting and the position reliability after mounting. The purpose is to provide.

  An optical pickup device according to the present invention includes a light projecting optical system that projects a light beam emitted from a light source onto an optical disk that records or reproduces information, and focuses the light beam reflected by the optical disk on a light receiving element to form an image. A light receiving optical system, and a parallel plate-shaped light beam separating means for separating a light beam traveling through the light receiving optical system and a light beam traveling through the light projecting optical system in a housing. The first mounting portion provided on the floor surface of the housing has a predetermined hardness at least two locations on the bottom surface facing the floor surface side of the housing among the two end surfaces facing each other. At least two portions of the upper surface opposite to the lower surface are fixed with an adhesive, and the upper surface of the second mounting portion erected from the floor surface of the housing is more than the first adhesive. The second adhesive with low hardness It is deposited, and, so as to cover at least a portion of the second adhesive, in which is fixed with high hardness third adhesive than the second adhesive.

  The thermal expansion coefficient of the third adhesive is smaller than the thermal expansion coefficient of the second adhesive.

  The first adhesive uses a thermosetting resin, and the second adhesive and the third adhesive use an ultraviolet curable resin.

  The first mounting portion is a protrusion provided on the floor surface of the housing, and the second mounting portion is a light flux of the light receiving optical system on a wall surface standing from the floor surface of the housing. These are substantially columnar support protrusions provided on both sides of the opening through which passes.

  In addition, the support protrusion has a step portion for supporting the lower surface of the light beam separating unit at a lower portion of a support surface facing a surface on which the light beam of the light receiving optical system of the light beam separating unit is incident, and the support surface The light beam separating means has a notched groove in a portion facing the lower end of the back surface.

  According to the present invention, it is possible to prevent deformation when the light beam separating means is mounted, and after the light beam separating means is attached, the light beam separating means can be used for a long period of time regardless of the installation location or the temperature change of the environment. Thus, it is possible to provide an optical pickup device provided with a light beam separating means that can be maintained at a fixed position in a constantly stable state, in other words, 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 accompanying drawings.
FIG. 1 shows an optical pickup device 1 of an optical disc apparatus according to an embodiment of the present invention. The optical pickup device 1 is an optical base 2 that constitutes a housing portion of the optical pickup device 1 and the optical base 2. And an objective lens actuator 3 connected so as to be displaceable by electromagnetic force. In FIG. 1, it is difficult to accurately describe the arrangement of the internal optical elements, so the state when viewed from a plurality of directions is shown on the same plane for convenience.

  The opt-base 2 includes a main optical system excluding an objective lens 31 and a diaphragm unit, which will be described later, and is used to separate an optical path between a light source 21 using a semiconductor laser, a diffraction grating 22, and a forward path and a return path. Reflected by the optical disk D and the optical path for the projecting optical system for projecting the laser light from the light source 21 onto the optical disk D A rising mirror 25 for changing the direction of the optical path for the returning light receiving optical system, and a reflecting mirror arranged on the optical path (after passing through the half plate 23) of the reflected light reflected by the optical disk D and returned by the optical disk D 26 and a correction plate 27 for correcting astigmatism (referred to as an “AS correction plate”), a light receiving element 28, and the like.

  The light source 21 uses a semiconductor laser that emits laser light having a predetermined wavelength for reading or writing on the optical disc D. The diffraction grating 22 generates 0th-order light and ± 1st-order diffracted light for reading and servo. The half plate 23 reflects the laser beam incident from the light source 21 side and bends the optical path by 90 degrees, transmits the laser beam reflected by the optical disc D, and separates the optical path Q of the light receiving optical system from the optical path P of the light projecting optical system. It is supposed to let you. The AS correction plate 27 corrects the angle of astigmatism generated in the half plate 23 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 that the angle is 45 degrees with respect to the dividing line provided on the light receiving surface of the light receiving element. 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 this relationship is used to enter the optical path. Although the rotation is 60 degrees, the description of this relationship is omitted. For the light receiving element 28, for example, a PIN photodiode is used as a photoelectric conversion element.

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 3 of the present embodiment can be displaced in the radial (R) direction of the optical disk D in order to apply tracking servo, and can be displaced in the thickness direction of the optical disk D in order 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, the fine movement of the objective lens actuator 3 (objective lens 31) is not shown in the figure so that the light beam from the light source (semiconductor laser) 21 follows the track of the optical disk D. When the moving operation of a predetermined distance or more which cannot be followed by the servo mechanism is necessary, the opt base 2 is moved using a traverse mechanism (not shown).

  In the present embodiment, the light projecting optical system includes a light source 21, a diffraction grating 22, a collimator 24, a rising mirror 25, an objective lens 31, a diaphragm portion, and the like (however, the half plate 23). Is excluded from the projection optical system). On the other hand, the light receiving optical system includes an objective lens 31 and a diaphragm, a rising mirror 25, a collimator 24, a reflecting mirror 26, an AS correction plate 27, a light receiving element 28, and the like (however, the half plate 23). Is excluded from the light receiving optical system). In the present embodiment, since coherent light is used as the reading light or writing light of the optical disc D, a polarizing plate and a polarizing beam splitter (PBS) are used in combination instead of the half plate 23. The light path P of the light projecting optical system and the light path Q of the light receiving optical system may be separated.

Next, the attachment of the half plate 23 to the opt base 2 will be described with reference to FIGS.
As shown in FIGS. 2 and 4, the opto-base 2 is separated from the floor surface 2A by a space of a required width W in order to secure the optical path Q of the light receiving optical system (to secure the opening 2E). A pair of left and right standing wall surfaces 2B provided in an upright state, a pair of support protrusions (second mounting portions) 2C having a substantially columnar shape arranged in parallel with each other on opposite ends of the standing wall surface 2B, and the floor surface 2A Each of the support protrusions 2C and a pair of protrusions (first attachment portions) 2D provided at corresponding portions are provided.

  Among these, as shown in FIG. 3, the support protrusion 2C is formed so that its height is the same as or slightly higher than the height of the half plate 23 (the distance between the upper and lower surfaces, which are the opposing two end surfaces). The wall surface portion sagged toward the tip constitutes a support surface 2H that supports the incident surface I (surface opposite to the exit surface E) of the half plate 23. Further, a step 2F that supports the edge side of the lower surface of the half plate 23 is provided on the support protrusion 2C so as to protrude from the base of the support protrusion 2C, and the side edge below the incident surface I of the half plate 23. A notch groove 2G is provided at a portion facing 23A (see FIG. 3).

  This notch groove 2G cannot be formed vertically at the corner that forms the boundary between the floor surface 2F and the support surface 2H, and is rounded (a curved surface is formed) when viewed microscopically. This is because of this. That is, even if the corners of the floor surface 2F and the support surface 2H are rounded, by providing this notch groove 2G, the half plate 23 can be attached to the floor surface 2A of the opt base 2 with high accuracy. It can be secured.

  The protruding portion 2D protrudes from the floor surface 2A by the same amount as the height from the floor surface 2A to the stepped portion 2F of the opt base 2, and the lower surface of the half plate 23 is fixed. The protrusion 2D has a perfect circular cross section in the present embodiment, but is not particularly limited to this cross sectional shape.

  Next, the half plate 23 will be described. In the case of the present embodiment, the half plate 23 is formed in a parallel plate shape with thin plate glass or the like, and reflects the laser light on the light path P of the light projecting optical system and also the light path Q of the light receiving optical system. In order to refract and transmit the laser beam above, the surface portion is coated with a dielectric multilayer film or the like.

Next, a method for fixing the half plate 23 to the opt base 2 will be described with reference to FIGS.
(1) First, as shown in FIG. 4, a region indicated by hatching on the upper surface of a pair of projecting portions 2D provided on the floor surface 2A side of the opt base 2 (this is referred to as “first adhesive region S1”). First, the first adhesive 41 is applied. As shown in Table 1 below, the first adhesive 41 used here uses a thermosetting resin such as a thermosetting epoxy resin having a predetermined high hardness after curing.

(2) Next, in FIG. 4, in a state in which the lower surface of the half plate 23 is supported by the projecting portion 2 </ b> D and the stepped portion 2 </ b> F using a non-illustrated fixture or the like, and the back surface of the half plate 23. By fixing the half plate 23 to the opt base 2 side with the (incident surface I) in contact with the wall surface (support surface 2H) of the support protrusion 2C, the half plate 23 is brought to the floor surface side of the opt base 2. Secure firmly.
(3) Thereafter, the stationary jig is put into a thermosetting furnace (not shown) and heated to a required temperature to cure the first adhesive 41.

(4) Next, as shown in FIG. 2, in the state where the half plate 23 is fixed to the floor surface 2A side of the opt base 2 with the first adhesive 41, the upper surface of the half plate 23 and the support protrusion 2C Two substantially circular regions (referred to as “second bonding region S2”) extending over the end surface (including a part of the support surface 2H perpendicular to the upper end surface) (FIGS. 4 and 5A). )), The second adhesive 42 is applied. The second adhesive 42 used here is an ultraviolet curable epoxy resin having a predetermined hardness lower than that of the first adhesive 41 as shown in Table 1 below.
(5) Next, the second adhesive 42 is cured by irradiating the second adhesive region S2 coated with the second adhesive 42 with ultraviolet rays.

(6) Thereafter, in FIG. 2, a partial region covering the second adhesive 42 after curing (this is referred to as “lamination region”), the upper surface of the half plate 23 and the opt base from the edge of this lamination region An outer edge region (both front end side regions in the major axis direction in an ellipse or an ellipse) of the second adhesive region S2 extending in a direction (called a “transverse direction”) across the upper surface of the two-side support protrusion 2C; The third adhesive 43 is applied to a region formed by (referred to as “third adhesive region S3”). That is, the third adhesive 43 is applied so as to have a two-layer structure that is wider than the second adhesive region S2 and partly laminated on the second adhesive 42. 23, the upper end surface of the support protrusion 2C and the upper surface of the half plate 23 are fixed by the second adhesive 42 having a hardness lower than that of the first adhesive 41, and from the second adhesive 42. Also, a part of the second adhesive 42 is covered and fixed by the third adhesive 43 having high hardness.
As shown in Table 1 below, the third adhesive 43 used here is an ultraviolet curable epoxy resin having a predetermined hardness higher than that of the second adhesive 42. Such an adhesive having a high hardness generally has a smaller linear expansion coefficient α or body expansion coefficient β than the second adhesive 42.
Therefore, the position of the half plate 23 can be maintained with high accuracy with respect to the opto base 2 over a long period of time.
(7) Finally, when the third adhesive 43 is cured by irradiating the third adhesive region S3 coated with the third adhesive 43 with ultraviolet rays, as shown in FIG. 2 and FIG. 2, the half plate 23 is fixed in a state where the half plate 23 is accurately positioned.

  Here, as for the first adhesive 41 to the third adhesive 43 used for fixing the half plate 23 to the opto base 2, those shown in Table 1 below are preferable.

  The first adhesive 41, the second adhesive, and the third adhesive are not limited to those shown in Table 1, but have a predetermined hardness, and the hardness of the first adhesive is higher than the hardness of the second adhesive. High and the hardness of the third adhesive can be higher than that of the second adhesive.

  FIG. 6A shows the correlation between the hardness of the adhesive and the variation angle of the half plate. FIG. 6A is a graph showing the angle of variation that occurs when the first adhesive and the second adhesive are of various hardnesses and the half plate 23 is fixed to the opto base 2. In FIG. 6A, the solid line indicates Rad fluctuation, and the broken line indicates Tan fluctuation. The Rad fluctuation is a fluctuation defined by the angle change component in the Rad direction shown in FIG. 5, and the Tan fluctuation is a fluctuation defined by the angle change component in the Tan direction shown in FIG.

  As shown in FIG. 6 (A), as the hardness of the adhesive increases, the fluctuation angle in both the Rad direction and the Tan direction decreases, and the fluctuation angle depends on the adhesive hardness. Since it is known that the fluctuation angle is preferably suppressed to 1 minute or less as the fluctuation angle, if the hardness (Shore D) is 70 or more, this can be sufficiently satisfied. Here, the shore D refers to the hardness of the durometer type D. For example, when the hardness is 50 degrees, it is generally expressed as D50.

  However, if both the hardness of the first adhesive 41 and the second adhesive 42 are increased after hardening, the aberration (that is, various aberrations such as coma, spherical aberration, astigmatism) caused by the half plate 23 is changed. This is not preferable because the recording / reproducing characteristics may be greatly deteriorated when used in a recording / reproducing apparatus. It is known that these aberrations are preferably 25 (rms) or less, preferably 5 (rms) or less. Here, rms (Root Mean Square) is defined by the following equation.

  For these aberrations, as the adhesive (first adhesive 41) used for fixing the lower surface of the half plate 23, the above-mentioned hardness (Shore D) of 70 or higher is used, while the adhesive used for fixing the upper surface is used. Aberration can be reduced by using an agent (second adhesive 42) having a low hardness. FIG. 6B shows the correlation between the hardness of the adhesive used for fixing the upper surface (second adhesive 42) and the fluctuation angle of the half plate. 6B, the first adhesive 41 having a hardness (Shore D) 70 is used, and only the second adhesive 42 having various hardnesses is used, and the half plate 23 is attached to the opt base 2. It is a graph which shows the aberration at the time of making it adhere | attach.

  As shown in FIG. 6B, it can be seen that the amount of aberration generated increases as the hardness of the second adhesive 42 increases. Accordingly, if the upper surface of the half plate 23 is bonded with a material having a high hardness after the second adhesive 42 is cured, the aberration greatly increases from the point where the Shore D exceeds 40, which is not preferable. When the upper surface of the half plate 23 is fixed with the second adhesive 42, aberration can be suppressed by using a material having a hardness (Shore D) of 40 or less.

  In this way, by using the first adhesive 41 having a predetermined hardness and using the second adhesive 42 having a lower hardness, the variation in mounting the half plate is reduced, and various aberrations are reduced. Can be reduced.

  However, as the adhesive generally has a lower hardness, the coefficient of thermal expansion increases. Therefore, when the half plate 23 is fixed with an adhesive having a low hardness, the position of the half plate 23 may fluctuate due to a large temperature change. When the position of the half plate 23 varies, the incident position of the light receiving element 28 (see FIG. 1) on which the light reflected and refracted by the half plate 23 is also varied (this is referred to as “PD variation”). Therefore, this variation is reduced by the third adhesive 43 having a higher hardness than the second adhesive 42.

  The third adhesive 43 reinforces the adhesive strength between the upper surface of the half plate 23 fixed by the second adhesive 42 having a low hardness and the upper end surface of the support protrusion 2C, and stably maintains the position with high accuracy. It is something to be made. Since the third adhesive 43 is used after the upper surface of the half plate 23 and the upper end surface of the support projection 2C are fixed with the second adhesive, the aberration does not change even if the Shore D exceeds 40. Referring to the result of FIG. 6 (A), a material having a hardness (Shore D) of 70 or more is preferable as in the first adhesive.

  Next, the measurement result of the PD fluctuation accompanying the temperature fluctuation of the half plate 23 according to this embodiment bonded to the opto base 2 by the bonding method according to the present invention will be described. The optical pickup device 1 in FIG. 1 is used to check the incident position of the light beam center when the light emitted from the LD as the light source 21 is incident on the PD as the light receiving element 28 after being reflected by the half plate 23. I went there. Here, ΔPDX (%) and ΔPDY (%) are defined by the following equations.

ΔPDX = [(A + B) − (C + D)] / (A + B + C + D) × 100 (1)
ΔPDY = [(A + D) − (B + C)] / (A + B + C + D) × 100 (2)

Here, A to D are the names of the four divided regions on the light receiving surface of the light receiving element 28 shown in FIG. 7 and the values of electromotive currents (photocurrents) generated from terminals provided in the regions. Both shall be indicated. However, in the present embodiment, in the testing machine that performs the above test, the current (photocurrent) generated by the light receiving element (PD) 28 is converted into a voltage by a built-in amplifier, and the voltage value at that time is converted. As shown, the unit is mV.
In addition, the above is a configuration in which a signal is reproduced by irradiating a PD with a light beam. However, when the adhesive undergoes thermal expansion (or contraction) due to environmental temperature changes, the half plate is subjected to thermal expansion. The angle of the incident surface of the half plate changes even slightly. Therefore, for example, if the incident angle changes by θ, the angle change is doubled by the principle of the light lever, so that the incident position of the light beam on the PD becomes a relatively large change.

  The experimental results are shown in FIGS. Here, in each plot of FIG. 8A, the upper part of the half plate 23 is fixed to the opt base 2 with two types of adhesives (second adhesive and third adhesive) having a two-layer structure (this embodiment) When the environmental temperature of the installation site is changed (changed from −30 ° C. to + 85 ° C.) using an optical pickup (which has the same configuration as that of the embodiment), it is the incident position of the light beam center on the PD at each temperature. Moreover, each plot of FIG. 8 (B) shows an installation place using an optical pickup (comparative example) in which the upper part of the half plate 23 is fixed to the opt base 2 with a single adhesive (second adhesive). When the environmental temperature is changed (changed from −30 ° C. to + 85 ° C.), the incident position of the light beam center on the PD at each temperature is shown.

  According to this, in FIG. 8A, ΔPDX≈9 (%) and ΔPDY≈7 (%), whereas in FIG. 8B, ΔPDX≈15 (%), ΔPDY≈38 ( %), And it can be confirmed that the PD variation is significantly smaller in this embodiment than in the comparative example.

  Accordingly, by using the second adhesive and the third adhesive as in the present embodiment, the upper part of the half plate 23 is formed into an adhesive structure having a two-layer structure, so that even under a large temperature change environment, the PD The knowledge that fluctuation can be minimized was obtained. As a result, the half plate 23 can be fixed and maintained at a fixed position with high positioning accuracy in a stable state for a long period of time regardless of the temperature change of the installation location or environment. The half plate 23 capable of greatly improving the shape reliability at the time of mounting and the position reliability after mounting can be realized.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention.

  The optical pickup device of the present invention can suppress the deformation and positional change of the light beam separating means with high accuracy against a large temperature change in the installation place or environment, in other words, position reliability. For optical pickup devices mounted on in-vehicle electronic devices that have a particularly high effect, particularly vibration and temperature changes, or next-generation optical disc recording / reproducing devices capable of recording information at a higher density than DVDs This is useful for an optical pickup device to be mounted.

The block diagram which shows the optical pick-up apparatus of embodiment of this invention The perspective view which shows the half plate adhering to the opto base in the optical pick-up apparatus of embodiment of this invention Sectional drawing which shows the attachment state to the opto base of the half plate in the optical pick-up apparatus of embodiment of this invention Explanatory drawing which shows the attachment state to the opto base of the half plate in the optical pick-up apparatus of embodiment of this invention (A) The top view which shows the attachment state to the opto base of the half plate in the optical pick-up apparatus of embodiment of this invention (B) The attachment state to the opto base of the half plate in the optical pick-up apparatus of embodiment of this invention is shown. Bottom view (A) Graph showing the correlation between the hardness of the adhesive and the fluctuation angle of the half plate (B) Graph showing the correlation between the hardness of the adhesive used for fixing the upper surface and the fluctuation angle of the half plate Explanatory drawing which shows the four division area in the light-receiving surface of the light receiving element provided in the testing machine which has the structure similar to the optical pick-up apparatus of this invention (A) The figure which shows an example of the measurement result of PD fluctuation | variation accompanying the temperature fluctuation | variation of the half plate in the optical pick-up apparatus of embodiment of this invention (B) The half plate upper surface was fixed only by the 2nd adhesive (single-layer adhesion). Of an example of the measurement result of PD fluctuation accompanying temperature fluctuation of the half plate at the time Configuration diagram showing a conventional general optical pickup device

Explanation of symbols

1 Pickup device 2 Opt-base (housing)
2A Floor surface 2B Standing wall surface 2C Support protrusion (second mounting part)
2D protrusion (first mounting part)
2E Opening 2F Step 2G Notch Groove 2H Support Surface 23A Side Edge 3 Objective Lens Actuator 21 Light Source Using Semiconductor Laser 22 Diffraction Grating 23 Half Plate (Flux Separating Means)
24 Collimator 25 Rising mirror 26 Reflecting mirror 27 AS correction plate 28 Light receiving element (PD)
DESCRIPTION OF SYMBOLS 3 Objective lens actuator 31 Objective lens 41 1st adhesive agent 42 2nd adhesive agent 43 3rd adhesive agent E Output surface I Incident surface P Optical path of light projection optical system Q Optical path of light reception optical system S1 1st adhesion area S2 2nd adhesion Area S3 Third adhesion area

Claims (5)

A light projecting optical system for projecting a light beam emitted from a light source onto an optical disk for recording or reproducing information; a light receiving optical system for focusing the light beam reflected by the optical disk on a light receiving element; In an optical pickup device having a housing with a parallel plate-shaped light beam separating means for separating a light beam traveling in an optical system and a light beam traveling in a light projecting optical system,
The light beam separating means includes
A first adhesive having a predetermined hardness at each of at least two portions of a lower surface facing the floor side of the casing among the two end faces facing each other, on a first mounting portion provided on the floor surface of the casing. It is fixed with
At least two places on the upper surface opposite to the lower surface are a second adhesive having a hardness lower than that of the first adhesive with respect to the upper end surface of the second mounting portion erected from the floor surface of the housing. An optical pickup device fixed and fixed with a third adhesive having a hardness higher than that of the second adhesive so as to cover at least a part of the second adhesive.   The optical pickup device according to claim 1, wherein a thermal expansion coefficient of the third adhesive is smaller than a thermal expansion coefficient of the second adhesive. The first adhesive is a thermosetting resin,
3. The optical pickup device according to claim 1, wherein the second adhesive and the third adhesive use an ultraviolet curable resin. The first attachment portion is a protrusion provided on the floor surface of the housing,
The second mounting portion is a substantially columnar support protrusion provided on both sides of an opening portion through which a light beam of the light receiving optical system passes on a wall surface standing from a floor surface of the housing. 2. An optical pickup device according to claim 1.   The support protrusion includes a step portion for supporting the lower surface of the light beam separating unit at a lower portion of a support surface facing a surface on which the light beam of the light receiving optical system of the light beam separating unit is incident. The optical pickup device according to claim 4, wherein a notch groove is provided in a portion facing the lower end of the back surface of the light beam separating means.

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