JP2009004044A - Optical head, manufacturing method thereof, and optical recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical head which is hardly deformed even if exposed to a high temperature environment, and to provide a manufacturing method thereof and an optical recording and reproducing device. <P>SOLUTION: The optical head 1 has a housing to which a semiconductor laser which emits an optical beam for recording or reproducing digital information on an optical recording medium is fitted directly or through a laser holder. The semiconductor laser or the laser holder is fixed so as to fill a gap between the bottom face 22b and the side face 22s of the semiconductor laser or the laser holder 22 and the housing 21 with an adhesive 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an optical head for recording or reproducing digital information on an optical recording medium such as an optical disk,
The present invention relates to a manufacturing method and an optical recording / reproducing apparatus.

The optical head irradiates the optical system with a predetermined spot diameter and irradiates the optical beam with an optical system composed of a plurality of optical elements for guiding a light beam emitted from a semiconductor laser as a light source. An objective lens driving device that drives an objective lens that guides the light beam to the optical system in a tracking direction, a focusing direction, and the like, and a housing that is mounted with the optical system and the objective lens driving device and is slidable in the radial direction of the optical recording medium It is roughly structured.

  In recent years, the demand for thin optical heads has increased with the increase in the number of notebook PCs sold. Therefore, in a housing for mounting a semiconductor laser or a laser holder, etc., zinc (Zn), aluminum (Al), magnesium (Mg), etc. in order to reduce the weight, size and thickness while ensuring the desired rigidity. There are those formed of various metals or alloys thereof (for example, see Patent Document 1). In general, the semiconductor laser, the laser holder, or the like is fixed to the housing by multipoint adhesion using an adhesive.

JP 2005-285166 A

In order to reduce the weight, size, and thickness of the optical head, it is necessary to make the housing as thin as possible and to have a complicated shape by removing unnecessary portions in terms of structure. If the housing is thin, a slight deformation of the housing may occur in a high temperature or high temperature and high humidity environment. The cause of this is not clearly clarified, but for one thing, when molding a housing, the density of the metal, such as magnesium, used in the housing may not be uniform. Due to the difference in thermal expansion due to the above, there is a possibility that when the temperature is raised, stress is generated in the housing, and the housing is slightly deformed. For this reason, since the optical head has to be adjusted in the order of microns, the optical axis is changed even if the housing is subtly deformed, which makes it difficult to ensure performance.

  Conventionally, multi-point bonding has been used to fix a structure (component). If the housing requires sufficient strength, the housing will not be deformed, so that the above method does not cause a problem. However, as described above, in the case of an optical head that is thin, especially 9.5 mm height drive, etc., there is a limit to the rigidity of the housing. In the above method, the optical axis changes with the deformation of the housing, and the light receiving element This is a cause of so-called photodiode balance change. Along with this, an offset is generated in the tracking signal, which causes a deterioration in recording / reproducing performance. For example, it is a situation where it is necessary to ensure characteristics in an operation under a high temperature environment, a high temperature (high temperature and high humidity) storage test, or the like.

The above-described problem also applies to the case where the semiconductor laser alone or the laser holder in which the semiconductor laser is accommodated is fixed to the housing.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an optical head, an optical head manufacturing method, and an optical recording / reproducing apparatus that can solve the above-described problems.

In order to achieve the above object, an optical head, an optical head manufacturing method, and an optical recording / reproducing apparatus according to the present invention are configured as follows.
The first optical head (corresponding to claim 1) is an optical head having a housing to which a semiconductor laser emitting a light beam for recording or reproducing digital information on an optical recording medium is attached directly or via a laser holder. The semiconductor laser or laser holder is fixed so as to fill a gap between the bottom and side surfaces of the semiconductor laser or laser holder and the housing with an adhesive.
The second optical head (corresponding to claim 2) is an optical head having a housing to which a semiconductor laser emitting a light beam for recording or reproducing digital information on an optical recording medium is directly or via a laser holder. The semiconductor laser or the laser holder is fixed so as to fill a gap between the bottom of the semiconductor laser or the laser holder and the housing with the housing with an adhesive.
The third optical head (corresponding to claim 3) is characterized in that, in the above configuration, the adhesive is preferably made of an epoxy resin.
A first optical head manufacturing method (corresponding to claim 4) includes a housing in which a semiconductor laser that emits a light beam for recording or reproducing digital information on an optical recording medium is attached directly or via a laser holder. A method of manufacturing an optical head, the step of filling a gap between the bottom of the semiconductor laser or the laser holder and / or the housing on the side with a first adhesive made of an epoxy resin, and the semiconductor laser or the laser holder at a desired position A step of adjusting the position, a temporary fixing step of filling and fixing the second adhesive made of an ultraviolet curable resin in the gap between the both ends of the semiconductor laser or the laser holder and the housing, and the first adhesive And a main fixing step of curing.
The first optical recording / reproducing apparatus (corresponding to claim 5) includes any one of the first to third optical heads.

  According to the present invention, since the gap between the bottom surface and / or side surface of the semiconductor laser or laser holder and the housing is filled with the adhesive, the bottom surface and / or side surface of the semiconductor laser or laser holder and the housing are integrated. This eliminates the disadvantages of the thin optical head that the overall rigidity is increased and the housing is easily deformed, and a highly reliable optical head can be made.

  FIG. 1 is a perspective view of an optical head according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the optical system of the optical head 1 according to the embodiment of the present invention. The optical head 1 is configured so that digital information can be recorded or reproduced on each of two types of optical recording media 2 (2a and 2b) having different physical track pitches. The first optical recording medium 2a is an optical recording medium having a CD-ROM, CD-R / RW, and a structure and storage capacity equivalent to these. On the other hand, the second optical recording medium 2b is an optical recording medium having a DVD-ROM, DVD-RAM, DVD ± R / RW, and a structure and storage capacity equivalent to these.

  The optical head 1 includes semiconductor lasers 3 and 4 as light sources that emit light beams to a housing 21. The semiconductor laser 3 emits a light beam (first light beam) having a wavelength of 650 nm for recording / reproducing a DVD. On the other hand, the semiconductor laser 4 emits a light beam (second light beam) having a wavelength of 780 nm for recording / reproducing a CD. In FIG. 1, the semiconductor laser 3 and the semiconductor laser 4 are shown in a state where they are put in a laser holder 22 and a laser holder 25, respectively.

The semiconductor laser 3 and the semiconductor laser 4 are provided so that the optical axis of the first light beam emitted from the semiconductor laser 3 and the optical axis of the second light beam emitted from the semiconductor laser 4 are orthogonal to each other. It has been.
A diffraction grating 5 is disposed at a predetermined position on the light emitting side of the semiconductor laser 3. The diffraction grating 5 is optimal for dividing the first light beam emitted from the semiconductor laser 3 into three light beams (0th-order main beam and ± 1st-order subbeams) (not shown). A diffraction grating pattern is formed. That is, the diffraction grating 5 is formed on the surface (information recording surface) of the optical recording medium 2.
The first light beam emitted from the semiconductor laser 3 is divided so that the ± 1st order sub beam is condensed at a symmetrical position with a predetermined distance in the track direction around the condensing position of the main beam.

A diffraction grating 6 is also arranged at a predetermined position on the light emission side of the semiconductor laser 4. The diffraction grating 6 has a second light beam emitted from the semiconductor laser 4 and three light beams (0
A diffraction grating pattern optimized to divide into the next main beam and ± 1st order sub beam) (not shown) is formed. That is, in the diffraction grating 6, on the surface (information recording surface) of the optical recording medium 2, the ± first-order sub beam is condensed at a symmetrical position with a predetermined distance in the track direction around the condensing position of the main beam. In this manner, the second light beam emitted from the semiconductor laser 4 is divided.

The light transmitting side of the diffraction grating 5 as viewed from the semiconductor laser 3, the light transmitting side of the diffraction grating 6 as viewed from the semiconductor laser 4, and the light of the first light beam emitted from the semiconductor laser 3 A dichroic prism 7 is disposed at a position where the axis and the optical axis of the second light beam emitted from the semiconductor laser 4 are orthogonal to each other. The dichroic prism 7 has a substantially cubic shape. The dichroic prism 7 transmits the first light beam substantially completely, and substantially totally reflects the second light beam in the direction perpendicular to the inner joint surface 7a.

A polarizing beam splitter 8 is disposed on the surface 7c side opposite to the surface 7b facing the diffraction grating 5 of the dichroic prism 7. The polarization beam splitter 8 has an inner joint surface 8a.
The light beam from the dichroic prism 7 is reflected by 90% or more in the perpendicular direction and is incident on a quarter-wave plate 9 to be described later, and the remaining several percent is transmitted to transmit a front monitor photodetector 13 to be described later. To enter. The polarization beam splitter 8 transmits a return light beam (hereinafter referred to as “return light beam”) from the quarter-wave plate 9 and makes it incident on a sensor lens 14 described later.

A quarter wave plate 9, a collimating lens 10, a rising prism 11, and an objective lens 12 are arranged in this order on the surface 8c side of the polarization beam splitter 8 that is adjacent to and orthogonal to the surface 8b facing the dichroic prism 7. Has been placed.
The quarter-wave plate 9 converts the linearly polarized component of the main beam from the polarization beam splitter 8 and the P-polarized beam of the ± first-order sub-beam (hereinafter referred to as “outgoing light beam”) into a circularly polarized component. . The quarter-wave plate 9 converts the circularly polarized component of the return light beam from the collimating lens 10 into a linearly polarized component in a direction orthogonal to the polarization direction of the outgoing light beam, that is, the linearly polarized component of the S-polarized light. Convert.

The collimating lens 10 converts the diffused light beam from the quarter-wave plate 9 into a parallel light beam, and converts the parallel light beam from the rising prism 11 into a focused light beam. The rising prism 11 reflects the forward light beam from the collimating lens 10, bends the optical path, rises in the direction of the optical recording medium 2, and enters the objective lens 12. The rising prism 11 reflects the return light beam from the objective lens 12, bends the optical path, and enters the collimator lens 10.
The objective lens 12 condenses the parallel light beam from the rising prism 11 on the information recording surface of the optical recording medium 2 and converts the reflected light beam from the optical recording medium 2 into a parallel light beam.

A front monitor photodetector 13 is disposed on the surface 8d side of the polarizing beam splitter 8 opposite to the surface 8b facing the dichroic prism 7. The front monitor photodetector 13 measures the light intensity of the first or second light beam emitted from the semiconductor laser 3 or 4. Based on the output of the front monitor photodetector 13, the outputs of the semiconductor lasers 3 and 4 are adjusted.

On the other hand, the surface 8e opposite to the surface 8c facing the quarter-wave plate 9 of the polarizing beam splitter 8 is provided.
On the side, the sensor lens 14 and the photodetector 15 are arranged in this order. Sensor lens 1
4 expands the main beam and the ± first-order sub beam reflected by the optical recording medium 2 at a predetermined optical system magnification. The sensor lens 14 is configured to be movable in the optical axis direction when the optical head 1 is assembled and adjusted. That is, by moving the sensor lens 14 in the optical axis direction, the focal position of each of the main beam and ± first-order sub beam reflected on the optical recording medium 2 on the light receiving surface of the photodetector 15 is optically detected. It is configured so that it can be adjusted. The photodetector 15 photoelectrically converts each received light beam in each divided light receiving area (not shown) and outputs an electrical signal.

  In addition to the optical system shown in FIGS. 1 and 2, the optical head 1 has an objective lens driving device (not shown) for driving the objective lens 12, and a housing 21 shown in FIGS. The housing 21 is made of, for example, various metals such as zinc (Zn), aluminum (Al), magnesium (Mg), or alloys thereof. Although not shown, the objective lens driving device is configured to be supported by the housing 21 by being attached to the upper portion of the housing 21.

In FIG. 3, the portion A of the housing 21 is configured to be fixable with an adhesive or the like after the semiconductor laser 4 is positioned. FIG. 4 shows the housing A of FIG.
It is the expansion perspective view seen from the angle different from FIG. On the other hand, in FIG. 3, the portion B of the housing 21 is configured to be fixable with an adhesive or the like after the semiconductor laser 3 is positioned. FIG. 5 is an enlarged perspective view of the portion B of the housing 21 as seen from an angle different from that in FIG. A light detector 15 is attached to a portion C of the housing 21.

Further, the housing 21 includes therein the diffraction gratings 5 and 6, the dichroic prism 7, the polarization beam splitter 8, the quarter wavelength plate 9, and the collimating lens 10.
The rising prism 11, the front monitor photodetector 13, the sensor lens 14, and the photodetector 15 are formed in a shape that can be accommodated.

Next, a method for manufacturing the optical head 1 having the above configuration will be described. As a premise, parts other than the semiconductor lasers 3 and 4 and the photodetector 15, for example, a dichroic prism 7, a polarizing beam splitter 8, a quarter-wave plate 9, a collimating lens 10, and a rising prism 1 are used.
1. It is assumed that the front monitor photodetector 13 and the sensor lens 14 have already been adjusted in position and fixed using an adhesive or the like. The adhesive used in this case may be an ultraviolet curable resin, a thermosetting resin, or an epoxy resin.

  (1) First, the semiconductor laser 3 is fixed to a gap between the bottom surface 22b, the side surface 22s, and the housing 21 of the laser holder 22 in which the semiconductor laser 3 is accommodated, for example, as shown in FIG. After embedding a thermosetting adhesive 23 such as an epoxy resin, it is held by a holding member (not shown) above the portion B of the housing 21.

FIG. 6 is a view showing a state where the portion B of the housing 21 is greatly simplified and the laser holder 22 in which the semiconductor laser 3 is accommodated is finally fixed.

  Here, the reason why the ultraviolet curable resin is not used as the adhesive 23 is that when the ultraviolet curable resin is used, the adhesive 23 is not sufficiently irradiated with ultraviolet rays, and a desired adhesive strength cannot be obtained.

(2) Next, while emitting the first light beam from the semiconductor laser 3, the laser holder 22 is moved using a holding member (not shown) and set to a desired position.

(3) Next, as shown in FIG. 6, for example, an ultraviolet curable adhesive 24 whose main component is a modified acrylate is provided in a gap provided between the left and right ends of the laser holder 22 and the housing 21. Then, the ultraviolet irradiator is activated to irradiate the adhesive 24 with ultraviolet rays, and the adhesive 24 is cured and temporarily fixed.

(4) Next, the semiconductor laser 4 is also temporarily fixed through the above (1) to (3).
(5) Next, the optical detector 15 is fixed at a desired position after position adjustment using a known method.
(6) Next, the semi-finished optical head that has undergone the steps up to (5) above is housed in a thermostat set to a predetermined temperature and held for a certain period of time. As a result, the adhesive 23 is cured, so that the laser holders 22 and 25 in which the semiconductor lasers 3 and 4 are accommodated are permanently fixed to the bottom part of the part B and the part A of the housing 21, respectively.
(7) Next, the semi-finished optical head that has undergone the steps (6) above is taken out from the thermostat.

  As described above, according to the embodiment of the present invention, the adhesive 23 such as an epoxy resin that is fixed in a certain gap between the bottom surface 22b and the side surface 22s of the laser holder 22 and the housing 21 is embedded and the position adjustment is performed. After that, the gap portion provided between the left and right end portions of the laser holder 22 and the housing 21 is filled with an ultraviolet curable adhesive 24 and temporarily fixed. Thereafter, the laser holder 22 is permanently fixed by fixing the adhesive 23 under the certain conditions. Similarly to the laser holder 22, the laser holder 25 is also attached to the housing 21.

Therefore, in order to reduce the weight, size, and thickness of the optical head 1 and to improve the heat dissipation effect, the optical head 1 has a thin and complicated shape and is easily deformed by high temperature, high temperature and high humidity. Even when the housing 21 is used, the bottom surface and / or side surface of the semiconductor laser or laser holder and the housing are fixed so that the gap between the bottom surface and / or side surface of the semiconductor laser or laser holder and the housing is filled with an adhesive. This eliminates the disadvantages of the thin optical head that the overall rigidity is increased and the housing is easily deformed, and a highly reliable optical head can be made. As a result, even when a reliability test is performed under high temperature and high humidity, time passes after mounting, or the surrounding environment changes, the optical axis of the optical system is shifted and the optical head 1 There is little risk of performance degradation.

  In the above-described embodiment, when the laser holder 22 is fixed to the housing 21, the adhesive is filled in the gap between the bottom surface, the side surface, and the housing. However, the present invention is not limited thereto, and the gap between the bottom surface and the housing is filled. Alternatively, the gap between the side surface and the housing may be filled.

  FIG. 7 is a schematic diagram showing the configuration of the optical recording / reproducing apparatus according to the embodiment of the present invention. This optical recording / reproducing apparatus includes an optical head 41, a spindle motor 42, a spindle motor drive circuit 43, a controller 44, a feed motor 45, a feed motor drive circuit 46, and a laser drive circuit according to the above-described embodiment. 47 and a lens driving circuit 48.

The spindle motor drive circuit 43 is controlled by the controller 44 under the control of the spindle motor 4.
2 is driven to rotate the optical recording medium 2. The controller 44 includes a tracking error signal TES, a focus error signal FES, and an information reading signal SUM supplied from the optical head 41.
Based on the above, the spindle motor drive circuit 43, the feed motor drive circuit 46, the laser drive circuit 47, and the lens drive circuit 48 are controlled.

The feed motor drive circuit 46 drives the feed motor 45 under the control of the controller 44 to move the optical head 41 in the radial direction of the optical recording medium 2. The laser drive circuit 47 generates a laser drive signal for driving the semiconductor lasers 3 and 4 (see FIG. 2) constituting the optical head 41 under the control of the controller 44, and supplies the laser drive signal to the optical head 41. The lens driving circuit 48
Under the control of the controller 44, a lens drive signal for controlling the focusing, tracking, and tilt of the objective lens 12 (see FIG. 2) constituting the optical head 41 is generated and supplied to the optical head 41.

The controller 44 includes a focus servo tracking circuit 51, a tracking servo tracking circuit 52, a skew adjustment circuit 53, and a laser control circuit 54. The focus servo tracking circuit 51 focuses the light beam emitted from the optical head 41 on the information recording surface of the rotating optical recording medium 2 based on the focus error signal FES supplied from the optical head 41. The focus servo signal is generated and supplied to the lens driving circuit 48.

The tracking servo follow-up circuit 52 applies the optical head 41 to the eccentric signal track of the optical recording medium 2 based on the tracking error signal TES supplied from the optical head 41.
A tracking servo signal for tracking the beam spot of the light beam emitted from the lens is generated and supplied to the lens driving circuit 48. The skew adjustment circuit 53 adjusts the skew for tilting the objective lens 12 (see FIG. 2) constituting the optical head 41 in the radial direction or the tangential direction based on the tracking error signal TES supplied from the optical head 41 or the like. A signal is generated and supplied to the lens driving circuit 48. The laser control circuit 54 generates an appropriate laser drive signal based on the recording condition setting information recorded on the optical recording medium 2 extracted from the information reading signal SUM supplied from the optical head 41.

The controller 44 may be configured by hardware such as a digital signal processor (DSP) and a sequencer, and the CPU (central processing unit) is operated by the focus servo tracking circuit 51, the tracking servo tracking circuit 52, and the skew adjustment circuit 53. The processing performed by the laser control circuit 54 may be executed based on a program.

  Thus, according to the embodiment of the present invention, the optical recording / reproducing apparatus is configured using the optical head 41 according to the above-described embodiment. Accordingly, since the optical head can be reduced in weight, size, and thickness, the optical recording / reproducing apparatus itself can be reduced in weight, size, and thickness. Furthermore, the optical recording / reproducing apparatus performs a reliability test, passes time after mounting, or changes the ambient environment during mounting, causing the optical axis of the light beam to shift and There is little risk of head performance degradation. Therefore, digital information can be recorded or reproduced on the optical recording medium in a good state.

  In the above-described embodiment, an example of an optical head provided with two semiconductor lasers as a light source or an optical recording / reproducing apparatus provided with only one optical head has been described. However, the present invention is not limited to this. The present invention can also be applied to an optical head provided with one or more light sources or an optical recording / reproducing apparatus provided with a plurality of optical heads.

(Example)
In this example, the laser holder is fixed to the housing by attaching an adhesive at multiple points, and the laser holder is fixed by a conventional fixing method, and the bottom and side surfaces of the laser holder according to the embodiment of the present invention In the case of an optical head in which an adhesive is embedded in the gap of the housing and the laser holder is fixed, a comparative experiment was performed on the change in the incident position of the laser beam on the photodetector after exposure to a high temperature environment. In the experiment, four light beams A, B, C, and D shown in FIG. 8 are detected after the light beam of the semiconductor laser 3 placed in the laser holder 22 is reflected by the optical recording medium 2 shown in FIG. The detection values detected by the respective detection areas A, B, C, and D are expressed by the equations (1) and R and T values expressed by the expressions (2). Thus, the incident position of the laser beam on the photodetector was evaluated. In the equations (1) and (2), A, B, C, and D indicate detection values in the respective detection regions A, B, C, and D, respectively. A circle S shown in FIG. 8 shows an example of a spot that hits the light receiving surface of the light beam photodetector.

(Equation 1)
R = 100 × {(A + D) − (B + C)} / (A + B + C + D) (%) (1)

(Equation 2)
T = 100 × {(A + B) − (C + D)} / (A + B + C + D) (%) (2)

  FIG. 9 shows the measurement before the T value and R value of the conventional optical head and the optical head according to the present embodiment were raised to a high temperature, when the temperature was raised to 65 ° C., and returned to room temperature of 25 ° C. It is a graph which shows a result. FIG. 9 (a) shows the measurement results obtained when the T value was raised to a high temperature for a conventional optical head and five samples, and the temperature was raised to 65 ° C. and then returned to a room temperature of 25 ° C. 9 (b) is a result measured when the R value was raised to a high temperature for a conventional optical head and five samples, and after a high temperature of 65 ° C., the temperature was returned to a room temperature of 25 ° C. The variability after exposure is increased. On the other hand, FIG. 9C shows a sample of 10 optical heads having a laser holder bonded by the bonding method described in the present embodiment before the T value was raised to a high temperature and 65 ° C. FIG. 9D shows the result of measurement when the temperature was returned to room temperature of 25 ° C., and FIG. 9D shows R for a sample of 10 optical heads having a laser holder bonded by the bonding method described in this embodiment. It is the result measured when it returned to room temperature of 25 degreeC, after making a value high temperature, after making 65 degreeC high temperature. It can be seen that the change after exposure to high temperature is smaller than the conventional one. Thus, in the optical head manufactured by the manufacturing method according to the embodiment of the present invention, it can be seen that the change in the T value and the R value is very small even when exposed to a high temperature compared to the conventional one. It was speculated that the deformation of the housing due to exposure to high temperature was reduced, and it was found that a good effect was exhibited.

  As described above, according to the present embodiment, since the gap between the bottom surface and / or side surface of the semiconductor laser or laser holder and the housing is filled with the adhesive, the bottom surface and / or side surface of the semiconductor laser or laser holder is fixed. The housing becomes an integral structure, the overall rigidity is improved, and the disadvantage of the thin optical head that the housing is easily deformed under environmental conditions such as temperature conditions can be eliminated, and a highly reliable optical head can be made.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design can be changed without departing from the scope of the present invention. Is included in the present invention.
For example, in each of the above-described embodiments, the present invention is applied to the case where the laser holder in which the semiconductor laser is accommodated is adjusted and then fixed to the housing using an adhesive.
It is not limited to this. The present invention provides a semiconductor laser as a light source alone, a laser unit in which a semiconductor laser and a light receiving element that receives a return light beam and a hologram element are integrated, or a photodetector after position adjustment, and then an adhesive is used for the housing. It can also be applied when fixed.
Moreover, each embodiment mentioned above can divert each other's technique as long as there is no contradiction or problem in particular in its purpose and configuration.

1 is a perspective view of an optical head according to an embodiment of the present invention. It is the schematic which shows the structure of the optical system of the optical head which concerns on embodiment of this invention. It is a perspective view which shows the structure of a housing. . FIG. 4 is an enlarged perspective view of a portion A of the housing shown in FIG. 3 viewed from an angle different from that in FIG. 3. It is the expansion perspective view seen from the angle different from FIG. 3 of the B part of the housing shown in FIG. It is a figure for demonstrating the manufacturing method of the optical head which concerns on embodiment of this invention. It is the schematic which shows the structure of the optical recording / reproducing apparatus which concerns on embodiment of this invention. It is a schematic diagram of the photodetector divided | segmented into four area | regions. The graph which shows the result measured when it returned to room temperature of 25 degreeC before making T value and R value high temperature with respect to the conventional optical head and the optical head which concerns on this embodiment, after making 65 degreeC high temperature. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical head 2 Optical recording medium 2a 1st optical recording medium 2b 2nd optical recording medium 3,4 Semiconductor laser 5,6 Diffraction grating 7 Dichroic prism 7a, 8a Joint surface 7b, 7c, 8b, 8c, 8d, 8e Surface 8 Polarizing beam splitter 9 Quarter wave plate 10 Collimating lens 11 Rising prism 12 Objective lens 13 Photo detector for front monitor 14 Sensor lens 15 Photo detector 21 Housing 22, 25 Laser holder 23, 24 Adhesive 42 Spindle Motor 43 Spindle motor drive circuit 44 Controller 45 Feed motor 46 Feed motor drive circuit 47 Laser drive circuit 48 Lens drive circuit 51 Focus servo follow-up circuit 52 Tracking servo follow-up circuit 53 Skew adjustment circuit 54 Laser control circuit

Claims (5)

An optical head having a housing to which a semiconductor laser that emits a light beam for recording or reproducing digital information on an optical recording medium is attached directly or via a laser holder,
An optical head, wherein the semiconductor laser or laser holder is fixed so that a gap between a bottom surface and a side surface of the semiconductor laser or laser holder and the housing is filled with an adhesive. An optical head having a housing to which a semiconductor laser that emits a light beam for recording or reproducing digital information on an optical recording medium is attached directly or via a laser holder,
An optical head, wherein the semiconductor laser or the laser holder is fixed so that a gap between the semiconductor laser or the laser holder and the housing on the bottom surface or side surface thereof is filled with an adhesive.   The optical head according to claim 1, wherein the adhesive is made of an epoxy resin. A method of manufacturing an optical head having a housing to which a semiconductor laser emitting a light beam for recording or reproducing digital information on an optical recording medium is attached directly or via a laser holder,
A step of filling a gap between the semiconductor laser or the bottom of the laser holder and / or the side of the housing with the first adhesive made of epoxy resin;
A position adjusting step for adjusting the semiconductor laser or the laser holder to a desired position;
A temporary fixing step of filling and fixing a second adhesive made of an ultraviolet curable resin in a gap between the semiconductor laser or the laser holder and the housing; and
A main fixing step of curing the first adhesive;
A method of manufacturing an optical head, comprising: An optical recording / reproducing apparatus comprising the optical head according to claim 1.

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