JP4449738B2 - Optical head - Google Patents

Description

The present invention relates to an optical head for recording and / or reading data by irradiating an optical disc with light.

In recent years, as an image, audio, or information recording medium, an optical disk that can be recorded and / or read by irradiating light is often used. As the optical disc, a CD (Compact Disc), a DVD (Digital Versatile Disc) and the like are widely used. An optical disc apparatus that records and / or reads data on the optical disc using the optical disc as a recording medium includes an optical head that irradiates a recording surface of the optical disc with laser light and detects reflected light.

FIG. 2 shows the layout of the optical head. As shown in FIG. 2, the laser light source 11 , the mirror Mr,
A collimator lens 3, an objective lens 4, a beam splitter Bs, and a light receiving element Pd are provided. The laser light emitted from the laser optics 11 is reflected by the mirror Mr and enters the collimator lens 3. The laser light incident on the collimator lens 3 is emitted as parallel light and enters the objective lens 4. The laser light incident on the objective lens 4 is irradiated onto the recording surface of the DVD medium Ds.

At this time, the laser beam is focused on the recording layer of the DVD medium Ds, and the optical axis and DV
Laser light is irradiated so that the recording layer of the D media Ds is perpendicular. Beam splitter B
s is a prism that transmits half of the incident laser light and reflects half of it, and guides the light reflected by the DVD medium Ds to the light receiving element Pd. The light receiving element Pd converts light into current, and reads data depending on the intensity of light.

FIG. 5 shows a perspective view of a conventional laser optical system. The laser optical system 91 is attached to the base Bs, and includes a laser light source 92 and a laser holder 93 into which the laser light source 92 is press-fitted.
And a holder elastic support member 94 that supports the laser holder 93.

Although the laser holder 93 is not limited to this, here, it has a rectangular parallelepiped shape, and a laser light source 92 is detachably attached to the central portion. The holder elastic support member 94 is a rectangular bottom portion 940 that contacts the base Bs, is connected to the bottom portion 940 at a right angle, and is connected to the bottom portion 940 at a right angle, a first support portion 941 that covers substantially the entire side surface of the laser holder 93, First support portion 941
And a second support portion 942 that supports a part of the side surface of the laser holder 93.

As shown in FIG. 5, the laser light source 92 includes a power supply terminal 921 for supplying power. By supplying power from the power supply terminal 921, laser light is emitted from the laser light source 92. The base Bs and the holder elastic support member 94 are formed with through-holes through which laser light passes, although not shown.

A procedure for attaching the laser optical system 91 to the base Bs will be described below. The laser holder 93 into which the laser light source 92 is press-fitted is attached to the holder elastic support member 94. At this time, an engagement convex portion is formed on the first support portion 941 and the second support portion 942 of the holder elastic support member 94, and an engagement concave portion is formed on a portion corresponding to the engagement convex portion of the laser holder 93. Yes. By engaging the engaging convex portion and the engaging concave portion, the bottom portion of the laser holder 93 can be supported so as not to contact the bottom portion 941 of the holder elastic support member 94. A holder elastic support member 94 is disposed on the base Bs.

The optical axis is adjusted so that the laser beam has a predetermined optical path. When the adjustment of the optical axis of the laser beam is completed, the adhesive 95 is applied to the first support portion 941 and the second support portion 942, and the holder elastic support member 94 and the laser holder 93 are bonded. The bottom 9 of the holder elastic support member 94
The adhesive elastic support member 94 can be bonded and fixed to the base Bs by applying the adhesive 95 to the base 40.

As a method for supporting and fixing a similar optical component, for example, in the invention described in Japanese Patent Application Laid-Open No. 2004-206801, a method of supporting a spring for holding a laser holder holding a laser unit as an optical component with a screw is shown. Yes. Furthermore, in the invention described in Japanese Patent Application Laid-Open No. 2002-304744, the laser light emitting element is fixed by attaching a fixing means such as a spring through an adjustment member such as a flexible plastic.
JP 2004-206801 A JP 2002-304744

When the laser light source 92 is attached to the base Bs, a thermosetting adhesive that is cured by heating as the adhesive 95 is often used. Thermosetting adhesives are easy to apply and harden due to their properties. However, thermosetting adhesives are vulnerable to environmental changes such as temperature and humidity, and when environmental tests are performed under multiple environmental conditions, adhesion is insufficient and the optical axis of the laser beam is deviated. Sometimes.

If the optical axis of the laser beam is deviated, it becomes difficult to irradiate the laser spot on which the laser beam is focused at the correct position of the data layer recorded on the optical disc. Due to the deviation of the laser spot, the data recorded on the optical disk may not be read correctly. If the data recorded on the optical disc cannot be read correctly, for example, if it is a DVD player, the video and audio may be interrupted, or in the worst case, it may not be able to be reproduced. In the case of a recordable optical head, a laser spot cannot be irradiated at a predetermined position, so that it becomes difficult to record correct data on an optical disk, or a very long time is required for recording. It becomes.

In the case of the invention described in Japanese Patent Laid-Open No. 2004-206801, even if the adhesion is insufficient, the screw presses the spring, so that the spring does not fall off and the optical axis of the laser beam is not easily displaced. However, since members such as screws and springs are required, the configuration is complicated, and it takes time and effort to manufacture and assemble.

In the case of the invention described in Japanese Patent Application Laid-Open No. 2002-304744, the laser light emitting element can be adjusted without removing the fixing means. Therefore, the laser light emitting element can be easily adjusted. However, the fixing means and the adjusting means must be attached in a stacked manner, increasing the attachment space. In addition, as in the case described above, the structure is complicated, making it difficult to manufacture and assemble,
take time.

Therefore, the present invention has a simple structure, can be manufactured and assembled without much time and effort, and is separated from the installation location even if the environmental conditions such as the temperature and humidity of the installation location change. It is an object of the present invention to provide an optical head having a laser optical system that can suppress this.

In the present invention, the optical axis of the laser beam irradiated from the laser optical system is difficult to shift, and accordingly,
An object is to provide an optical head capable of stably irradiating a recording layer of an optical disc with a laser beam.

In order to achieve the above object, the present invention provides an optical head in which a holder elastic support member and a base are bonded and fixed, a laser optical system for irradiating laser light, a mirror for reflecting the laser light, and the laser light. A collimator lens for collimating light, an objective lens for irradiating the optical disc with the laser beam, a beam splitter for splitting the light reflected by the optical disc, and a light receiving element for receiving the light split by the beam splitter The laser optical system is attached to the base, a laser light source, a laser holder into which the laser light source is press-fitted, the holder elastic support member that supports the laser holder, and 2 The holder elastic support member includes a rectangular bottom portion that is in contact with the base, and a direct contact with the bottom portion. Connected to the first covering substantially the whole surface of the side surface of said laser holder
A first support portion and a second support portion; and a second support portion connected to the bottom portion at a right angle, facing the first support portion and supporting a part of the laser holder. An engaging convex part that engages with an engaging concave part formed on each contact surface of the laser holder is formed on the part, and the fastening member is a plate that contacts the base and the bottom part of the holder elastic support member has a spring-like support portion, after said laser holder is adhered and fixed to the holder elastic support member, said fastening member is bonded and fixed is arranged so as to sandwich the base and the bottom of the holder elastic support member
To provide an optical head, characterized in that the.

According to this configuration, the fixing member is attached so as to sandwich the base and the holder elastic support member, so that the adhesive fixing the holder elastic support member to the base is peeled off by temperature, humidity, or the like. Thus, it is possible to prevent the holder elastic support member from being displaced or detached from the base.

Further, since the fastening member is elastically fixed, even if the thickness of the base and / or the bottom of the holder elastic support member changes, the holder elastic support member is pressed against the base with a predetermined elastic force. Therefore, the versatility is higher and the manufacturing cost of the laser optical system can be reduced accordingly. Furthermore, since the fastening member has a hairpin-like shape,
Assembling is easy, and accordingly, the assembly time and labor of the laser optical system can be reduced, and the assembly cost can be reduced.

According to the present invention, it has a simple structure, can be manufactured and assembled without much time and effort, and can be separated from the installation location even if the environmental conditions such as temperature and humidity of the installation location change. Therefore, it is possible to provide an optical head having a laser optical system that can prevent the optical axis of the laser light from shifting.

Further, according to the present invention, it is possible to provide an optical head capable of stably irradiating a recording layer of an optical disc with a stable optical axis of the laser light irradiated from the laser optical system.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a layout of an example of an optical head according to the present invention. The optical head A shown in FIG. 1 has substantially the same structure as the conventional one.
That is, the laser optical system 1, the mirror Mr, the collimator lens 3, the objective lens 4,
It has a beam splitter Bs and a light receiving element Pd. The laser light emitted from the laser optical system 1 is reflected by the mirror Mr, enters the collimator lens 3, changes into parallel light, and exits from the collimator lens 3. The laser beam emitted from the collimator lens 3 is the objective lens 4.
Is incident on the DVD medium Ds from the objective lens 4.

At this time, the laser beam is focused on the recording layer of the DVD medium Ds, and the optical axis and DV
Laser light is irradiated so that the recording layer of the D media Ds is perpendicular. Beam splitter B
s is a prism that transmits half of the incident laser light and reflects half of it, and guides the light reflected by the DVD medium Ds to the light receiving element Pd. The light receiving element Pd converts light into current, and reads data depending on the intensity of light. The irradiation order of the laser light to each member described above is not limited to this, and the order may be changed within a possible range.

FIG. 2 is a perspective view of a laser optical system used in the optical head according to the present invention, and FIG. 3 is a side view of the laser optical system shown in FIG. The laser optical system 1 shown in FIGS. 2 and 3 is attached to the base Bs of the optical head A. The laser light source 11, a rectangular parallelepiped laser holder 12 into which the laser light source 11 is press-fitted, and the laser holder 12 are elastically supported. A holder elastic support member 13 and a base member Bs and a fastening member 14 for stably and elastically fixing the holder elastic support member 13.

The laser holder 12 includes a press-fitting hole 121 for press-fitting the laser light source 11. The press-fitting hole 121 penetrates, and the laser beam is irradiated from the side opposite to the side into which the laser light source 11 is press-fitted. The holder elastic support member 13 is connected to the rectangular bottom portion 130, a first support portion 131 that is connected to the bottom portion 130 at a right angle, covers substantially the entire side surface of the laser holder 12, and is connected to the bottom portion 130 at a right angle. And a second support portion 132 that supports a part of the side surface of the laser holder 12. The laser light source 11 has a terminal 111 for supplying power, and laser light is irradiated by supplying power to the terminal 111.

The laser holder 12 includes a first support part 131 and a second support part 132 of the holder elastic support member 13.
The holder elastic support member 13 has a bottom portion 130 fixed to the base Bs. The holder elastic support member 13 and the base Bs are formed with through holes 13h and Bsh through which laser light passes. The laser holder 12 is attached so that the laser light emitted from the laser light source 11 passes through the through hole 13 h of the holder elastic support member 13. Moreover, it arrange | positions so that the central axis of the through-hole 13h of the holder elastic support member 13 and the through-hole Bsh of the base Bs may overlap. The laser beam is emitted through the through hole 13h of the holder elastic support member 13 and the through hole Bsh of the base Bs.

The first support portion 131 is not limited to this, but here, the two first engagement convex portions 13 facing inward are provided.
3 and the second support part 132 is also provided with a second engagement convex part 134 facing inward. The first engaging portion 133 is engaged with the first support portion 131 of the laser holder 12 in contact with the first supporting portion 131.
An engaging recess 121 is formed. A second engagement concave portion 122 that engages with the second engagement convex portion 134 is formed in a portion that contacts the second support portion 131 of the laser holder 12 (see FIG. 3). The first engagement convex portion 133 and the second engagement convex portion 134, the first engagement concave portion 121 and the second engagement concave portion 122.
, And the bottom portion 130 of the holder elastic support member 13 and the bottom surface of the laser holder 12 are prevented from contacting each other.

Although the fastening member 14 is not limited thereto, the fastening member 14 is formed by bending a single metal plate and has a hairpin-like shape. The fastening member 14 includes a first locking part 141, a second locking part 142, and a connection part 143 that connects the first locking part 141 and the second locking part 142. In the case of the laser optical system 1 shown in FIG. 2, the first locking portion 141 is in contact with the bottom 130 of the holder elastic support member 13, the second locking portion 142 is in contact with the base Bs, and the laser optical system 1 is separated from the base Bs. It prevents you from becoming.

The first locking portion 141 and the second locking portion 142 are the same as the leaf spring and can be elastically deformed.
According to this, the thickness of the bottom 130 of the holder elastic support member 13 and / or the base Bs
Even if the thickness changes, it can be elastically supported until it reaches a predetermined thickness.

4A to 4E show an assembly procedure of the laser optical system according to the present invention. First, the laser holder 12 is attached to the holder elastic support member 13 (FIG. 4A). At this time, base B
The through holes Bsh of s and the through holes 13h of the holder elastic support member 13 are arranged so that the central axes thereof coincide. That is, the first engagement convex portion 133 of the holder elastic support member 13 and the laser holder 12.
The first engagement recess 121, the second engagement protrusion 134, and the second engagement recess 122 are engaged. And the holder elastic support member 13 which attached the laser holder 12 to base Bs is arrange | positioned (
(See FIG. 4B).

Then, the optical axis of the laser light emitted from the laser light source 11 is adjusted. The adhesive 2 is applied to the end of the holder elastic support member 13, and the base Bs and the holder elastic support member 13 are bonded and fixed (FIG. 4C). The fastening member 14 is arranged and bonded and fixed so as to sandwich the base Bs and the holder elastic support member 13 (FIG. 4D). The first support part 131 of the laser holder 12 and the holder elastic support member 13 and the second support part 132 of the laser holder 12 and the holder elastic support member 13 are bonded and fixed with the adhesive 2 (FIG. 4E).

The laser optical system 1 can be attached to the base Bs by the above procedure. Further, the mounting procedure is not limited to this, and the laser optical system 1 can be securely fixed to the base Bs even if the mounting order is slightly changed, and the optical axis of the laser beam does not shift. Can be widely adopted.

The adhesive 2 for adhering and fixing the laser optical system 1 to the base Bs is not limited thereto, but is a thermosetting adhesive here, and may be removed by heat, humidity, or the like even after adhesion. Even when the adhesive is detached or loosened, it is possible to prevent the laser optical system 1 from being detached from the base Bs and to prevent the optical axis from being shifted by attaching the fastening member 14. Therefore, the laser beam can be stably irradiated, and the optical head A can be stably operated. Here, a thermosetting adhesive is described as an example of the adhesive, but the same applies to other adhesives.

The fastening member shown in the present embodiment is a member formed integrally, but is not limited thereto, and a wide variety of hairpin-like shapes can be adopted by combining a plurality of members. In the present embodiment, one laser light source 11 (holder elastic support member 13) is illustrated as having one fastening member 14, but is not limited thereto.
A plurality of them may be provided.

At least one of the inner surfaces of the first locking portion 141 and the second locking portion 142 of the fastening member 14 is formed with an engaging convex portion that prevents the fastening member 14 from coming off, and the bottom portion 133 of the holder elastic support member 13. In addition, examples in which an engagement concave portion is formed at a location corresponding to the engagement convex portion of the base Bs can be exemplified. According to this configuration, even if the adhesive bonding the fastening member 14 is peeled off, melted, or the like, the fastening member does not come off, so the arrangement state of the holder elastic support member 13 on the base Bs Can be maintained.

The optical head of the present invention can be applied to an optical disc apparatus that reads information by irradiating an optical disc such as a DVD, CD, or LD with laser light, or records information on a writable optical disc.

FIG. 3 is a layout diagram of an example of an optical head according to the present invention. It is a perspective view of the laser optical system used for the optical head concerning this invention. FIG. 3 is a side view of the laser optical system shown in FIG. 2. FIGS. 4A to 4E are diagrams showing the assembly procedure of the laser optical system according to the present invention. It is a perspective view of the conventional laser optical system.

Explanation of symbols

Ds Optical disk Mr Mirror Bs Beam splitter Pd Light receiving unit 1 Laser optical system 11 Laser light source 12 Laser holder 13 Holder elastic support member 14 Fastening member 2 Adhesive 3 Collimator lens 4 Objective lens

Claims (1)

An optical head in which a holder elastic support member and a base are bonded and fixed,
A laser optical system for irradiating laser light, a mirror for reflecting the laser light, a collimator lens for collimating the laser light, an objective lens for irradiating the optical disk with the laser light, and reflected by the optical disk a beam splitter for splitting the light, the beam
And a light receiving element that receives light split by the splitter .
The laser optical system is attached to the base, and sandwiches and fixes a laser light source, a laser holder into which the laser light source is press-fitted, the holder elastic support member that supports the laser holder, and two or more members. A fastening member,
The holder elastic support member is connected to the base having a rectangular shape, a first support portion that is connected to the bottom portion at a right angle, covers substantially the entire side surface of the laser holder, and is connected to the bottom portion at a right angle. A second support portion that faces one support portion and supports a part of the laser holder;
The first support part and the second support part are formed with engaging convex parts that engage with engaging concave parts formed on each contact surface of the laser holder,
The fastening member has a leaf spring-like support part that contacts the base and the bottom part of the holder elastic support member, and after the laser holder is bonded and fixed to the holder elastic support member, the fastening member is Adhered and fixed so as to sandwich the base of the holder elastic support member and the base
An optical head characterized by that .

Images