JPH1027371A - Integrated module of radiation light source, photodetector and electric input/output connection means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thinned optical head. SOLUTION: A shape of a pedestal integrating a radiation light source 1 and a photodetector 8 or an integrated module of the radiation light source, the photodetector and an electric input/output connection means is constituted so that an L is made larger than a W, and the radiation light source 1 and the photodetector 8 are arranged in the prolonging direction of the L, and thus, the W is reduced. For instance, the L is made 15mm extent, and the W is reduced to 3mm extent. The external size of the pedestal 9 or the module 21 is made in such a shape, and by constituting the optical head with the module 21, the mounted optical head is thinned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical head device for recording or reproducing information in an optical information device, and
The present invention relates to an integrated module of a radiation light source, a photodetector, and an electrical input / output connection means used to constitute the optical head device.

[0002]

2. Description of the Related Art Recently, there is a simplified optical system of an optical head using a hologram as shown in FIG. 6 (for example, Wai-Hon Lee "Horographic Optical").
Headfor Compact Disc Applications "Optical Engine
ering Vol.28 No.6 650-653 (1989)-Way von
Lee "Holographic Optical Head for Compact Disc Applications"
Optical Engineering Volume 28 Number 6 650-653 (1989)).

In FIG. 6, a light beam 2 emitted from a radiation light source 1 passes through a hologram 6, enters an objective lens, and is focused on an information carrier 5. The light reflected on the information carrier 5 enters the hologram 6 by following the original optical path in reverse. The hologram 6 has an astigmatic wavefront recorded thereon, and converts the diffracted light 71 into a four-divided photodetector 8 as shown in FIG.
1, the focus error signal (F
E) is obtained. FIG. 7B shows a state at the time of just focus, and FIGS. 7A and 7C show a state at the time of defocus. The focus error signal FE can be obtained by the calculation of FE = (S1 + S4)-(S2 + S3) (1).

Here, the radiation light source 1 and the photodetector 81 are integrated with a base 9 as shown in FIG. 8 to reduce the size of the optical head. In addition, an electric input / output connection with an external circuit is attached to the base 9 to make the radiation light source 1 emit light or to take out an output from the photodetector 81 to the outside.

[0005] As shown in Fig. 8, a module in which an electric input / output connection portion of a radiation light source, a photodetector, and an external circuit is formed in a hybrid manner is hereinafter referred to as a module. Although this module is composed of several components, this module itself can be regarded as a component constituting the optical head device. When the optical head is configured as shown in FIG. 6 using such a module, the optical head optical system is arranged in a group near one optical axis, and changes in temperature,
There is an effect that various signals can be detected stably without being substantially affected by displacement of components due to temporal distortion. Further, the light source 81 is
Are arranged close to each other, the radiation light source 1 and the photodetector 81 can be easily assembled with accurate relative positions.

Here, the shape of the base is usually the same as that of the package in which the semiconductor laser is placed, and is circular, and the size of the bottom surface is the same in any direction (W0 = L0).

[0007] There is also an example in which a similar optical head device is constituted by using a small prism (Japanese Patent Laid-Open No. Sho 64-46243).
No.).

[0008]

The shape of an optical disc is thin, at most several mm, despite its large area.
In miniaturizing an optical information device that performs recording and reproduction on this optical disk, thinning is the most important issue.

However, according to the above-mentioned conventional optical system configuration, the distance from the information carrier 5 to the radiation light source 1 and the photodetector 81 is increased to about 30 mm, so that the size required for the optical head, especially the thickness reduction, is required. There is a problem that cannot be realized. Also, since the direction of the connection between the input / output terminal portions of the radiation light source 1 and the photodetector 81 and the electrical input / output connection means to the external circuit is substantially radial, and not parallel,
There are problems that automation is difficult and that the process of attaching the connection takes time.

Therefore, in the present invention, it is possible to reduce the thickness of the optical head and obtain an optimum module for that purpose.
Further, it is an object to simplify the assembling process.

[0011]

According to the present invention, in order to solve the above-mentioned problems, an optical head device includes a radiation light source, and a light source configured to receive a light beam and generate an output corresponding to the light amount. An integrated module having a detector and an electrical input / output connection means for an external circuit, a means for bending an optical axis of a light beam emitted from the module substantially vertically, and an optical axis of the light beam substantially vertical An objective lens that receives the light beam bent by the bending means and converges on the information carrier, and receives the light beam reflected on the optical information carrier through the objective lens, splits the light beam, The module is provided with a branching means for leading to a photodetector of the module, and when a plane perpendicular to the optical axis of the objective lens is defined as an objective lens plane, the module has an optical axis of a light beam emitted from the module. The length of the direction substantially perpendicular to the optical axis of the light beam emitted from the module and substantially parallel to the objective lens surface is longer than the length of the direction substantially perpendicular to the objective lens surface. The optical head device is characterized by being arranged in the direction, or using a reflection means that bends the optical axis almost vertically, and,
The shape of the base on which the radiation light source and the photodetector are integrated is arranged so that the length of the base is almost perpendicular to the radiation axis of the radiation light source and almost parallel to the information carrier. Also reduce the length in the substantially perpendicular direction. Also, by making the direction of the connection between the input / output terminal portion of the radiation light source and the photodetector and the electrical input / output connection means to the external circuit parallel, it is easy to make the connection at the time of manufacturing. The module used in the device is the same as a radiation light source, a photodetector configured to receive a light beam and generate an output according to the light amount, and an electrical input / output connection means for an external circuit. An integrated module of a radiation light source, a photodetector, and electrical input / output connection means provided on a base, wherein the shape of the base or the outer shape of the module is a light beam emitted from the module. In a plane viewed from the axial direction, that is, in a plane substantially perpendicular to the light beam, a length in a second direction substantially perpendicular to the first direction is longer than a length in the first direction. Module To adult.

According to the present invention, the above configuration ensures a sufficient area for disposing the radiation light source, the photodetector, and the electrical input / output connection means to the external circuit in the module,
In addition, it is possible to reduce the shape in one direction perpendicular to the light beam emitted from the module.

In addition, the radiation light source and the photodetector can be arranged in a direction perpendicular to the thickness direction of the optical head. By arranging, the base or the module on which the radiation light source and the photodetector are arranged can be reduced in size in the thickness direction of the optical head. Therefore, by using the above-mentioned module in addition to using the bending means for bending the optical axis vertically, it is possible to reduce the thickness of the entire optical head.

Further, by making the connection directions substantially parallel to each other, the connection can be performed by the operation in the same direction, so that automation becomes easy.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining in principle the embodiment of the present invention. The radiation light source 1 usually uses a semiconductor laser, and in some cases includes an optical system for wavefront correction.
The description is omitted because it is not directly related to the present invention.

The light beam 2 emitted from the radiation light source 1 and emitted from the module 21 travels in a direction substantially parallel to the information carrier 5, and has an optical axis approximately 90 degrees in a direction perpendicular to the information carrier 5 by the mirror 3.
After being bent, the light is focused on the information carrier 5 by the objective lens 4. The light beam reflected on the information recording / reproducing surface of the information carrier 5 passes through the objective lens 4 again and enters the hologram 6. The diffracted light 7 generated at this time enters the photodetector 8. By calculating the output of the photodetector 8, a servo signal or an information signal can be obtained. here,
As focus error signal detection method, astigmatism method,
A double knife edge method, a spot size detection method, or the like can be used.

As a tracking error signal detection method, a well-known method such as a push-pull method may be used.

Further, the information signal can be obtained from the sum of a part or all of the diffracted light. By obtaining the information signal from the sum of a part or all of the diffracted light, it is possible to obtain the effect that the number of components can be further reduced, and the size, weight, and cost of the optical head device can be further reduced.

Next, the shape of a base for integrating the radiation light source 1 and the photodetector 8 or a module in which the radiation light source, the photodetector, and the electrical input / output connection means are integrated will be described.

By making L larger than W shown in FIG. 1, the radiation light source 1 and the photodetector 8 are arranged in the extending direction of L, and as a result, W is made smaller. For example, if L is set to about 15 mm and W
Is reduced to about 3 mm. By making the outer shape of the base 9 or the module 21 in such a shape and configuring the optical head using the module 21, the optical head mounted using the support 5 as shown in FIG. 2 can be made thin. . That is, when the plane perpendicular to the optical axis of the objective lens 4 is defined as the objective lens surface, the module 21
Is longer than the length in the direction substantially perpendicular to the optical axis of the light beam 2 emitted from the module 21 and substantially perpendicular to the objective lens surface.
By arranging the light beam 2 emitted from the module 21 in a direction in which the length in a direction substantially perpendicular to the optical axis of the light beam 2 and substantially parallel to the objective lens surface is longer, the thickness of the optical head is reduced.

As described above, the difference between the present invention and the conventional example is that the shape of the base or module is W0 = L0 in the conventional example, whereas the shape of the base or module is W> L in the present invention. Where you are. By setting the small (L) direction to the thickness direction of the optical head device, the effect of reducing the thickness of the optical head device can be obtained. In particular, if the base is rectangular as shown in FIG. 1, the processing of the base is easy, and the base can be arranged neatly in the automation line, so that the assembling becomes easy.

As another embodiment, the hologram 6 can be integrated with the base 9 by using a hologram support 13 as shown in FIG. With such a configuration, the distance between the hologram 6 and the base 1 is determined by the support 13, and the accuracy of this distance can be easily improved.
In addition, by rotating the hologram support 13, the hologram can be rotated to easily align the diffracted light 7 on the photodetector 8.

As still another embodiment, on a base having the above-described shape, electrical input / output connection means 10 for connecting to an external circuit are gathered outside in the long direction of the base as shown in FIG. By doing so, there is an effect that a space for installing the electrical input / output connection means 10 with an external circuit can be obtained without increasing the length of the base or the module in the short direction at all. Further, by arranging the connections to the input / output terminal portion 11 in parallel, the connections can be made only by the movement in the same direction at the time of assembling, so that automation is easy and the process time can be shortened.

Further, as another embodiment, it is possible to use a reflection type hologram 63 as shown in FIG. With such a configuration, the number of parts can be further reduced,
There is an effect that the optical head device can be reduced in size, thickness, weight, and cost.

[0026]

As is apparent from the above description, the present invention has an excellent effect that the optical head can be made thinner by reducing the length of the side perpendicular to the information carrier. Have. In addition, the electrical input / output connection means for the external circuit is gathered outside in the long direction of the base. By doing so, there is an effect that a space for installing an electrical input / output connection means with an external circuit can be taken up without increasing the length of the base or the module in the short direction at all.

Furthermore, the connection between the electrical input / output connection means with the external circuit and the radiation light source or the photodetector is substantially parallel, so that the assembly process is simplified and the cost can be reduced. However, the present invention greatly contributes to easy realization of a small and high-performance optical head.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical head according to an embodiment of the present invention.

FIG. 2 is an oblique projection view of an optical head according to an embodiment of the present invention.

FIG. 3 is a perspective view of an optical head according to another embodiment of the present invention.

FIG. 4 is an oblique projection view of a main part in still another embodiment of the present invention.

FIG. 5 is a perspective view of an optical head according to still another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a configuration of a conventional example.

FIG. 7 is a diagram showing a state of diffracted light for detecting a focus error signal on a photodetector in a conventional example.

FIG. 8 is an oblique projection view showing the configuration and shape of a main part in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radiation light source 2 Light beam 3 Mirror 4 Objective lens 5 Information carrier 6 Hologram 7 Diffracted light 8 Photodetector 9 Base 10 Electrical input / output connection means 11 Input / output terminal part 12 Connection 13 Hologram support 63 Reflection hologram

Claims (5)

[Claims] A semiconductor laser configured to receive a light beam and generate an output according to the amount of the light beam;
A photodetector arranged in close proximity to the semiconductor laser,
An integrated module of a semiconductor laser, a photodetector, and an electrical input / output connection unit, comprising an electrical input / output connection unit with an external circuit, and a light emitting point of the semiconductor laser in the integrated module. There is a free space in the vicinity of the light source, and the light beam emitted from the semiconductor laser is divergent light that spreads in all directions around the optical axis of the light beam, and the outer shape of the integrated module is emitted from the integrated module. In the plane viewed from the optical axis direction of the light beam to be emitted, that is, in the plane substantially perpendicular to the light beam, the length in the second direction substantially perpendicular to the first direction is longer than the length in the first direction. An integrated module of a semiconductor laser, a photodetector, and electrical input / output connection means, characterized by having a long length. 2. A semiconductor laser, configured to receive a light beam and generate an output according to the amount of light, and
A photodetector arranged in close proximity to the semiconductor laser,
An integrated module of a semiconductor laser, a photodetector, and an electrical input / output connection unit, comprising an electrical input / output connection unit with an external circuit, and a light emitting point of the semiconductor laser in the integrated module. There is a free space in the vicinity of the light source, and the light beam emitted from the semiconductor laser is divergent light that spreads in all directions around the optical axis of the light beam, and the outer shape of the integrated module is emitted from the integrated module. In the plane viewed from the optical axis direction of the light beam to be emitted, that is, in the plane substantially perpendicular to the light beam, the length in the second direction substantially perpendicular to the first direction is longer than the length in the first direction. Wherein the light emitting point of the semiconductor laser and the light detector provided on the light detector are arranged in a direction substantially parallel to the second direction. Target Integrated module of the power connection means. 3. A semiconductor laser, configured to receive a light beam and generate an output in accordance with the amount of light, and
A photodetector arranged in close proximity to the semiconductor laser,
An integrated module of a semiconductor laser, a photodetector, and an electrical input / output connection unit, comprising an electrical input / output connection unit with an external circuit, and a light emitting point of the semiconductor laser in the integrated module. There is a free space in the vicinity of the light source, and the light beam emitted from the semiconductor laser is divergent light that spreads in all directions around the optical axis of the light beam, and the outer shape of the integrated module is emitted from the integrated module. In the plane viewed from the optical axis direction of the light beam to be emitted, that is, in the plane substantially perpendicular to the light beam, the length in the second direction substantially perpendicular to the first direction is longer than the length in the first direction. Is long, and the electrical input / output connection portion is, with respect to the second direction,
An integrated module comprising a semiconductor laser, a photodetector, and electrical input / output connection means, the module being disposed outside the semiconductor laser and the photodetector. 4. The hologram according to claim 1, wherein the hologram receives a light beam incident on the integrated module, generates diffracted light, and guides the diffracted light to a photodetector disposed near a semiconductor laser. Is integrated with a base on which a semiconductor laser and a photodetector are arranged, a closed space is formed in the integrated module by the hologram, and the semiconductor laser and the photodetection are arranged close to each other in the closed space. Features an integrated module. 5. An integrated module according to claim 1, wherein the optical axis of the light beam emitted from the integrated module is bent substantially vertically by reflection, and the optical axis is bent. A refraction type objective lens that receives the light beam bent by the bending means and converges on the information carrier, and receives the light beam reflected on the optical information carrier by passing through the refraction type objective lens, A branching means for branching a light beam and leading the light beam to a photodetector disposed near the semiconductor laser in the integrated module, wherein a surface perpendicular to the optical axis of the refraction type objective lens is defined as an objective lens surface Sometimes, an optical axis of the light beam immediately after being emitted from the integrated module is substantially parallel to the objective lens surface, and the integrated module is longer than a length in a direction substantially perpendicular to the objective lens surface. An optical head device arranged in a direction substantially perpendicular to an optical axis of a light beam emitted from the integrated module and extending in a direction substantially parallel to the objective lens surface.