JPH103680A - Optical base of optical pickup - Google Patents

Abstract

(57) [Problem] To provide an optical base of an optical pickup in which an optical element can be easily incorporated into an optical base. SOLUTION: An optical base 11 of the optical pickup for accommodating and supporting a plurality of optical elements constituting the optical pickup.
At 0, a first housing portion 112ha for housing the base portion of the light detecting means, which is one of the optical elements, and a second housing portion 112hb for housing the condenser lens portion of the light detecting means are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, MD, C
The present invention relates to an optical pickup that reproduces a signal from an optical disk or records a signal on an optical disk in D, LD, data storage, and the like, and in particular, an optical base for housing and supporting an optical element or an optical element that constitutes such an optical pickup. It is related to the improvement of.

[0002]

2. Description of the Related Art An optical pickup of this kind includes a semiconductor laser element, a grating, a beam splitter, a collimator lens, a prism mirror, an objective lens, and a photodetector for monitoring, which are housed and supported by a frame or a support generally called an optical base. And a plurality of optical elements such as a photodetector for signal detection, and a two-axis actuator serving as a movable part of the objective lens.

[0003]

In the above-described optical pickup, since it is necessary to accurately reproduce the signal of the optical disk or to accurately record the signal on the optical disk, each optical element is emitted from the semiconductor laser element. It is necessary to arrange the optical beam on the optical axis of the optical beam with high accuracy. Here, the monitoring photodetector of each optical element is provided integrally with a prism-shaped base portion having a light-receiving element and one surface of the base portion, and receives a light beam emitted from the semiconductor laser element. It is composed of a hemispherical condenser lens for condensing light on the element.

[0004] Such a monitor photodetector is
Conventionally, it is difficult to accurately position the monitor photodetector on the optical axis of the light beam emitted from the semiconductor laser element because the condensing lens portion is pressed against the optical base and fixed in a bare state. In addition, there is a problem that external light enters from a gap between the monitor photodetector and the optical base, and the output monitor of the semiconductor laser element becomes inaccurate.

In view of the above, it is an object of the present invention to provide an optical base of an optical pickup in which an optical element can be easily incorporated into an optical base.

[0006]

According to the present invention, there is provided an optical base of an optical pickup for accommodating and supporting a plurality of optical elements constituting an optical pickup.
This is achieved by providing a first housing part for housing the base part of the light detecting means, which is one of the optical elements, and a second housing part for housing the condenser lens part of the light detecting means.

[0007] According to the above arrangement, since the housing portion of the optical base of the light detecting means, which is one of the optical elements, is housed so as to wrap the light detecting means, the positioning of the light detecting means becomes easy, and furthermore, the outside position is improved. Light incidence can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. It is not limited to these forms unless otherwise stated.

FIG. 1 is a plan view showing an example of an optical pickup to which an embodiment of an optical base according to the present invention is applied, and FIG. 2 is a plan view of the optical pickup as viewed from the back. The optical pickup 100 includes an optical base 1 which is a frame in which a biaxial actuator 120 and a plurality of optical elements 130 are integrally formed by, for example, die casting.
It is housed and supported in 10.

The optical base 110 is a slide base 111 for housing and supporting the biaxial actuator 120, an optical system housing 112 for housing and supporting each optical element 130, and integrated with the slide base 111 and fixed to the apparatus body side. And a fixing portion 113 to be formed.

The optical elements 130 are arranged as shown in the plan view of FIG.
31, a grating 132 which is a light splitting means for splitting the light beam emitted from the laser element 131, a beam splitter 133 which is a light splitting means for splitting the light beam from the grating 132, and this beam splitter 133 A collimator lens 135, which is a parallel light converting means for converting the light beam from the light beam into a parallel light beam, a prism mirror 136, which is a light path bending means for bending the light path of the light beam from the collimator lens 135, and An objective lens 137 as a light focusing means for focusing the light beam from the prism mirror 136 is provided.

[0012] Further, a wollaston split means which is fixed integrally with the beam splitter 133 and serves as a light splitting means for splitting an optical beam returning from the optical disk via the objective lens 137, the prism mirror 136 and the collimator lens 135. A multi-lens 138 which is housed in a multi-lens holder and is a light focusing means for converging the light beam from the Wollaston prism 134, and a light for detecting the light beam from the multi-lens 138. The monitor photodetector 139 is located at a position facing the signal detection photodetector 139 with the signal detection photodetector 139 and the beam splitter 133 interposed therebetween, and is a laser output monitor light detection means.
40 is provided.

[0013] The optical pickup 100 having the above configuration.
Now, an example of the operation will be described. The light beam emitted from the semiconductor laser element 131 is
2 is incident. The light beam that has entered the grating 132 is split and enters the beam splitter 133. The light beam incident on the beam splitter 133 is split, a part of the light beam is bent 90 degrees by the reflection surface 133 a formed on the beam splitter 133, and is incident on the monitoring photodetector 140.

The monitor photodetector 1
40 monitors the beam output of the light beam emitted from the semiconductor laser element 131 and the like. Here, since the monitor photodetector 140 is arranged so as not to be perpendicular to the incident optical axis on the optical path, the light reflected on the surface of the monitor photodetector 140 or the light receiving element surface will Penetration into the light beam passing through the optical element 130, that is, generation of stray light can be avoided as much as possible.

The remaining light beam split by the beam splitter 133 enters a collimator lens 135. The light beam incident on the collimator lens 135 is refracted and converted into parallel light, is bent 90 degrees by the reflection surface formed on the prism mirror 136, and is incident on the objective lens 137. The light beam incident on the objective lens 137 is refracted and focused on the surface of the optical disk.

The return light beam reflected on the surface of the optical disk is refracted again by the objective lens 137, reflected by the prism mirror 136, and collimated by the collimator lens 135.
And is incident on the beam splitter 133. Then, the return light beam incident on the beam splitter 133 is reflected by the reflection surface 133 formed on the beam splitter 133.
The light is bent by 90 degrees by a and enters the Wollaston prism 134.

The return light beam incident on the Wollaston prism 134 is split into three beams and is incident on the multi-lens 138. The return light beam incident on the multi-lens 138 is refracted and incident on the signal detection photodetector 139. The signal detection photodetector 139 detects a focusing control signal, a tracking control signal, and a reproduction signal based on the received return light beam.

FIG. 4 is a perspective view of the optical base according to the embodiment of the present invention as viewed obliquely from the upper right, FIG. 5 is a perspective view thereof as viewed obliquely from the upper left, and FIG. FIG. 7 is a plan view seen from the B direction, and FIG.
FIG. 9 is a side view as viewed from the direction D, FIG. 10 is a side view as viewed from the direction E, FIG.
1 is a side view as seen from the F direction.

The optical base 110 comprises the slide base 111, the optical system accommodating section 112 and the fixing section 113 as described above, and these are integrally formed by, for example, die casting. The slide base 111 is provided with a relatively large space 114 that can accommodate and support the biaxial actuator 120. Then, the fixed portion 1 integrally connected to the slide base portion 111
Reference numeral 13 is fixed to the apparatus main body via a bearing 115.

A plurality of recesses are formed in the optical system housing portion 112 in accordance with the outer shape of the optical element 130 to be housed and supported, and most of these recesses are open in the direction of arrow A in FIG. . Therefore, each of the optical elements 130 is inserted into these concave portions from the opening side and is accommodated and supported. Then, a shield cover is attached from above, and each optical element 130 is fixed.

That is, the multi-lens 1 is provided in the concave portion 112a.
A multi-lens holder accommodating 38 is inserted in the direction of arrow B in FIG. 4, and is pressed and fixed by a leaf spring of the shield cover. In addition, recess 1
Reference numeral 12a has a length capable of adjusting the position of the multi-lens holder in the longitudinal direction. A laser diode as the semiconductor laser element 131 is inserted into and fixed to the recess 112b from the direction of arrow F in FIG.
The grating 132 is inserted into the recess 112c from the direction of arrow B in FIG. 4, and is pressed and fixed by a leaf spring of the shield cover. Recess 112
At d, a beam splitter 133 and a Wollaston prism 134 integrated therewith are inserted and fixed from the direction of arrow B in FIG.

The collimator lens 13 is provided in the recess 112e.
5 is inserted and fixed from the direction of arrow B in FIG. A prism mirror 136 is inserted and fixed in the space formed between the support portions 112f, 112f and the support portion 112g in the direction of arrow B in FIG.
Further, the monitor photodetector 1 is provided in the recess 112h.
The condenser lens portion 40 and the base portion are brought into contact with each other from the direction of arrow D in FIG. 4, and the bottom side thereof is pressed down and fixed by the leaf spring of the pressing cover.

A characteristic part of the optical base 110 of the optical pickup 100 having the above configuration is a concave portion 112h.
And will be described in detail below. Here, FIG.
1 is a plan view showing an example of a general monitor photodetector, and FIG. 1B is a side view thereof. The monitor photodetector 140 is integrally provided on a prismatic base 142 containing the light receiving element 141 and on one surface of the base 142 parallel to the light receiving surface of the light receiving element 141. Beam to light receiving element 1
It is configured by a hemispherical condensing lens unit 143 for condensing light at 41. The electrode terminal 144 of the light receiving element 141
Is provided so as to protrude from the side surface of the base portion 142.

The concave portion 112h is formed such that the monitor photodetector 14
The first housing portion 112ha for housing the zero base portion 142 and the condenser lens portion 14 of the monitor photodetector 140
3 is configured by a second storage unit 112hb that stores the third storage unit 3. The first accommodating portion 112ha has a prismatic base portion 14.
2 is formed as a rectangular column-shaped concave portion that wraps around the side surface and is in close contact with the surface of the base portion 142 on the side where the condenser lens portion 143 is provided. Second storage section 112hb
Is formed as a hemispherical concave portion that wraps around the spherical surface of the hemispherical condenser lens portion 143 and is in close contact therewith.
Note that the reflection surface 13 formed on the beam splitter 133 is provided at the deepest portion of the second accommodation portion 112hb, that is, at the top of the hemisphere.
A hole 112i for guiding the light beam bent 90 degrees by 3a to the condenser lens portion 143 is provided.

Accordingly, AA shown in FIG. 7 of FIG.
As shown in the cross-sectional side view of the line, the partial cross-sectional plan view of FIG. 14A, and the perspective view of FIG. 15, the monitor photodetector 140 is set in the concave portion 112h so that the condenser lens portion 143 faces forward. 13 (B)
14A, a partial cross-sectional plan view of FIG. 14B, and a perspective view of FIG.
Is in close contact with the inner surface of the second housing portion 112hb, and the base portion 1 on the side where the condenser lens portion 143 is provided.
The surface 42 comes into close contact with the inner surface of the first housing portion 112ha.

As described above, the monitor photodetector 14 is used.
0 is the first accommodation section 112ha and the second accommodation section 112
Since the monitor photodetector 140 is wrapped and held, the monitor photodetector 140 is less likely to be displaced, and can be easily fixed with high positioning accuracy. In addition, since there is no gap between the monitoring photodetector 140 and the optical base 110, the output of the semiconductor laser element 131 can be accurately monitored by preventing the incidence of external light.
The monitor photodetector 140 housed in the recess 112h is pressed down and fixed by a leaf spring of a pressing cover whose bottom side is fixed to the optical base 110 by screws or the like.

The optical base 110 of the optical pickup 100 according to the above embodiment is used for a polarized optical pickup for reproducing a magneto-optical disk, a non-polarized optical pickup for a compact disk (CD) or a CD-ROM, and an optical disk apparatus. Can be applied to

[0028]

As described above, according to the present invention,
Since it is easy to incorporate the optical element into the optical base,
The number of assembling steps can be reduced, and the positioning accuracy can be improved so that signals on the optical disk can be reproduced and recorded more accurately.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an optical pickup to which an embodiment of an optical base according to the present invention is applied.

FIG. 2 is a plan view of the optical pickup of FIG. 1 as viewed from the back.

FIG. 3 is a plan view showing an example of an optical element of the optical pickup of FIG. 1;

FIG. 4 is a perspective view showing an embodiment of the optical base according to the present invention, as viewed obliquely from the upper right side;

FIG. 5 is a perspective view of the optical base of FIG.

FIG. 6 is a plan view of the optical base of FIG. 5 as viewed from a direction A.

FIG. 7 is a plan view of the optical base of FIG. 5 as viewed from a direction B.

FIG. 8 is a plan view of the optical base of FIG. 5 as viewed from a direction C.

FIG. 9 is a plan view of the optical base of FIG. 5 as viewed from a direction D.

FIG. 10 is a plan view of the optical base of FIG. 5 as viewed from a direction E.

11 is a plan view of the optical base of FIG. 5 as viewed from the direction F.

12A and 12B are a plan view and a side view illustrating an example of a light detection unit which is one of the optical elements incorporated in the optical base of FIG.

13 is a cross-sectional side view showing the incorporation of the optical element of FIG. 12 into the optical base of FIG. 5;

FIG. 14 is a plan view showing the incorporation of the optical element of FIG. 12 into the optical base of FIG. 5;

FIG. 15 is a perspective view showing the incorporation of the optical element of FIG. 12 into the optical base of FIG. 5;

FIG. 16 is a perspective view showing a state after the optical element of FIG. 12 is assembled into the optical base of FIG. 5;

[Explanation of symbols]

100 optical pickup, 110 optical base, 111 slide base, 112 optical system housing, 113 fixed part, 120 biaxial actuator, 130 ... Optical element, 131 ... Semiconductor laser element, 132 ... Grating, 133
..Beam splitter, 134 ... Wollaston prism, 135 ... Collimator lens, 136 ... Prism mirror, 137 ... Objective lens, 138 ...
Multi-lens, 139 ... Photodetector for signal detection, 133a, 136a ... Reflecting surface, 112a, 11
2b, 112c, 112d, 112e, 112h ...
Recess, 112f, 112g ... support, 112ha
..First storage section, 112hb... Second storage section, 1
12i ... hole

Claims (1)

[Claims] 1. An optical base of an optical pickup for accommodating and supporting a plurality of optical elements constituting an optical pickup, wherein: a first accommodating section for accommodating a base portion of a light detecting means which is one of the optical elements; An optical base for an optical pickup, comprising: a second housing section for housing a condenser lens section of the light detecting means.