JPH05323178A - Supporting structure for parallel plate type optical part - Google Patents

Abstract

PURPOSE:To prevent deformation caused by an optical part by forming a smooth reference surface on a base member, and abutting one end of the optical part on this reference part to attain supporting. CONSTITUTION:A beam splitter 9 is composed of a parallel plate-like half mirror, and supported by a spring member 10. on the base member 2, in a state where one end part of the beam splitter 9 is inserted into a recessed part 11. The spring member 10 is composed of a base part 18 whose length is almost the same as the length from the opening surface of the recessed part 11 to its back surface, and width is almost the same as an interval between two side surfaces 16 and 17 of the recessed part 11, and a spring part 19 which extends backward from one side edge of the base part 18 and whose tailing edge is bent to obtain a J-shape. The side surface 16 of the upper side of the recessed part 11 is formed so as to obtain 45 deg. angle with respect to both of the optical axes of a laser diode 5 and a photodiode 7, and the beam splitter 9 is pressed on the side surface 16, so that the attached state of the beam splitter 9 is regulated by using the side surface 16 of the upper side of the recessed part as the reference part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel support structure for parallel plate type optical components. More specifically, regarding a support structure for a parallel plate type optical component used in an optical pickup device or the like, distortion does not occur in the parallel plate type optical component attached to a base member, and high precision as an optical component can be achieved. An object of the present invention is to provide a novel support structure for a parallel plate type optical component.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show an example in which a conventional supporting structure for a parallel plate type optical component is applied to a supporting structure for a base member of a beam splitter of an optical pickup device.

Reference numeral a designates a base member having a vertical hole b penetrating in the vertical direction and a horizontal hole c extending from an intermediate portion of the vertical hole b to one side surface.

Reference numeral d designates a beam splitter which is arranged at a portion where the vertical hole b and the horizontal hole c of the base member a intersect so as to be inclined at an angle of 45 degrees with respect to the axis of these holes b and c. ..

Reference numerals e and e denote recesses formed in the base member a for separately supporting both ends of the beam splitter d. One of the recesses e and e is a vertical hole c in the base member a.
At the lower left corner of the intersection of the horizontal hole d and
Are formed so that their openings face each other at the upper right portion of the intersecting portion.

Further, the recess e is formed such that the distance between the two opposing side faces f and g forming the recess e is approximately twice the plate thickness of the beam splitter d, and the two recesses e and e are formed. The distance between the inner surfaces of the two is substantially equal to or slightly larger than the length of the beam splitter d.

Reference numeral h is a spring member for supporting both ends of the beam splitter d in the recesses e, e, the length of which is the same as that of the beam splitter d and the width thereof is approximately twice the plate thickness of the beam splitter d. And a spring portion j, which has a lower end bent from one end portion of one side edge along the longitudinal direction of the base portion i and is bent in a J shape.

Both ends of the beam splitter d are located in the recesses e, e, and then the spring member h is provided between the lower side surface of the beam splitter d and the lower side surfaces g, g of the recesses e, e. The spring parts j of j are inserted, and thereby the beam splitter d is supported by the base member a such that both ends thereof are pressed against the side faces f of the recesses e, e on the upper side.

[0009]

However, in the above-described conventional support structure for a parallel plate type optical component, the two recesses e for supporting the beam splitter d, and the side surface of the e on the side on which the beam splitter d is pressed. Unless f and f are smooth surfaces and are in the same plane, there is a problem that the beam splitter d whose both ends are pressed separately is distorted and the accuracy as an optical component is extremely deteriorated. It was

Therefore, in order not to lower the accuracy as an optical component, the flatness of the side surfaces f of the recesses e on the side to which the beam splitter d is pressed and the accuracy that these are in the same plane. Therefore, there is a problem that production efficiency is lowered and cost is increased.

It is also conceivable to fix the left and right ends of the beam splitter d to the recesses e, e with an adhesive. However, when this is done, when the adhesive changes, for example, shrinks due to aging. In particular, when changes such as contraction of the adhesive at the left and right ends of the beam splitter d are not the same (rather often, this is the case), internal stress occurs in the beam splitter d, which eventually causes distortion. Was almost always caused.

[0012]

Therefore, in order to solve the above-mentioned problems, the support structure of the parallel plate type optical component of the present invention forms a smooth reference surface on the base member, and the optical component has one end One of the flat surfaces is supported by the reference surface of the base member in a state of being in contact therewith.

[0013]

Therefore, according to the supporting structure of the parallel plate type optical component of the present invention, since the supporting part of the parallel plate type optical component to the base member is only one end, the supporting part can be supported. The generated distortion is generated only in the supporting portion, and no distortion occurs in the other portion, that is, the portion where the light is reflected or transmitted. Therefore, the accuracy of the optical component can be improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the supporting structure of the parallel plate type optical component of the present invention will be described below with reference to the embodiments shown in the accompanying drawings.

In each of the embodiments shown in the drawings, the supporting structure of the parallel plate type optical component of the present invention is applied to the supporting structure of the beam splitter of the optical pickup device.

FIG. 1 shows an example of an optical pickup device 1 to which a supporting structure for a parallel plate type optical component of the present invention is applied.

Reference numeral 2 is a base member having a vertical hole 3 penetrating in the vertical direction and a horizontal hole 4 extending from the middle portion of the vertical hole 3 to one side surface.

The vertical holes 3 and the horizontal holes 4 of the base member 2 are opened on the front surface (the paper surface side is the front surface and the paper spine side is the rear surface in FIG. 1).

Reference numeral 5 is a laser diode fixedly fitted in an opening on one side surface of the lateral hole 4, and 6 is a grating disposed between the laser diode 5 and the vertical hole 3. ..

Reference numeral 7 is a photodiode arranged at the lower end opening of the vertical hole 3, and 8 is a light receiving lens arranged above the photodiode 7.

Reference numeral 9 is a position approximately in the middle of the vertical hole 3 and is the horizontal hole 4.
Is a beam splitter placed at the corresponding position,
The beam splitter 9 is arranged so as to form an angle of 45 degrees with respect to both the optical axis of the laser diode 5 and the optical axis of the photodiode 7, as described later.

The beam splitter 9 is composed of a parallel plate half mirror and has a recess 11 formed as described later.
The spring member 10 supports the base member 2 with its one end inserted.

Reference numeral 12 is a collimator lens arranged at the upper end opening of the vertical hole 3, and 13 is an objective lens above the collimator lens 12 and supported by a biaxial actuator 14.

The beam light emitted from the laser diode 5, after passing through the grating 6, is reflected upward by the beam splitter 9 and irradiated on the disk surface 15 through the collimator lens 12 and the objective lens 13. ..

The return light reflected by the disk surface 15 passes through the beam splitter 9 and the light receiving lens 8 and is incident on the photodiode 7.

A recess 11 in which the beam splitter 9 is supported
Has a substantially U shape when viewed from the side, and has a vertical hole 3 in the base member 2.
Is formed at the lower left corner of the intersection of the horizontal hole 4 and the horizontal hole 4 so that the opening direction is directed obliquely upward and rightward.

The recess 11 is formed such that the distance between the two opposite side surfaces 16 and 17 forming the recess 11 is approximately twice the plate thickness of the beam splitter 9, and the recess 11 extends from the opening surface to the back. The length up to the surface is approximately 1/3 of the length of the beam splitter 9, and the extended surface of the upper side surface 16 of the recess 11 is either the optical axis of the laser diode 5 or the optical axis of the photodiode 7. It is also formed to form an angle of 45 degrees.

The spring member 10 has a length which is substantially the same as the length from the opening surface of the recess 11 to the back surface thereof, and a width which is substantially the same as the distance between the two side surfaces 16 and 17 of the recess 11. And a spring portion 19 that extends rearward from one side edge of the base portion 18 and whose rear end is bent in a J shape.

The spring portion 19 has a lower piece 19a projecting from the base portion 18 and a spring piece 19b having a dogleg shape in which the tip of the lower piece 19a is folded back upward and frontward and the front end is further bent toward the lower piece 19a. The length of the lower piece 19a is slightly smaller than the front-back width of the beam splitter 9, and the spring piece 1
The length of 9b is formed to be approximately 1/3 of the lower piece 19a.

The distance between the bent portion 19c of the spring piece 19b and the lower piece 19a is the distance between the two side surfaces 16 and 17 of the recess 11 when the spring member 10 receives no external force. It is formed to be slightly larger than the interval obtained by subtracting the thickness of the splitter 9.

Thus, the beam splitter 9 has one end in the longitudinal direction located in the recess 11, and then the lower surface of the beam splitter 9 and the lower side surface 17 of the recess 11.
The spring portion 19 of the spring member 10 is inserted from the front of the concave portion 11 between and.

The spring member 19 is inserted into the recess 11 by inserting the rear end of the spring portion 19 into the recess 11 from the front of the recess 11, and at this time, the lower piece 19a of the spring portion 19 is inserted into the recess 11. The spring piece 1 of the spring portion 19 on the lower side surface 17
By contacting the upper surface of the bent portion 19c of 9b with the lower surface of the beam splitter 9, the spring piece 19b is bent so as to reduce the gap between the lower piece 19a and the lower piece 19a, and the lower piece 19a is formed on the lower surface 17 of the recess 11. In addition, the bent portion 19c of the spring piece 19b is elastically contacted with the lower surface of the beam splitter 9 substantially at the center in the front-rear direction.

As a result, the beam splitter 9 is recessed 1
It is supported on the base member 2 so as to be pressed against the upper side surface 16 of the base member 1.

Although only one spring portion 19 of the spring member 10 is provided, the present invention is not limited to this, and two spring portions 19 are provided at positions separated in the length direction.
It is also possible to form two spring portions and press the beam splitter 9 against the upper side surface 16 of the recess 11 at two portions inside the recess 11.

The upper side surface 16 of the recess 11 is formed so as to form an angle of 45 degrees with respect to both the optical axis of the laser diode 5 and the optical axis of the photodiode 7, as described above. By pressing the beam splitter 9 on, the mounting state of the beam splitter 9 is regulated with the upper side surface 16 of the recess 11 as the reference surface.

Since one end of the beam splitter 9 in the length direction is supported by the base member 2 by the spring member 10, distortion occurs at the portion of the beam splitter 9 pressed by the spring member 10. No distortion occurs in the portion other than the pressed portion, that is, the portion where the laser beam is reflected or transmitted.

FIG. 3 shows a second embodiment of the support structure for a parallel plate type optical component of the present invention.

The second embodiment differs from the first embodiment in that the means for supporting the beam splitter in the concave portion is an adhesive, so that the second embodiment is different from the first embodiment. With regard to the description of the first embodiment, the differences from the first embodiment will be mainly described, and the other parts will be described with reference to the first embodiment.
The same reference numerals as those given to the same parts in the embodiment are given to omit the explanation.

Reference numeral 20 denotes a crossing portion of the vertical hole 3 and the horizontal hole 4 of the base member 2, which is a concave portion formed at a lower left corner thereof, and the concave portion 20 has a substantially U shape when viewed from the side. It is formed so that its opening direction is oriented at an angle of 45 degrees with respect to both the optical axis of the laser diode 5 and the optical axis of the photodiode 7.

The recess 20 is formed such that the interval between two opposing side faces 21 and 22 forming the recess 20 is slightly larger than the plate thickness of the beam splitter 9, and from the opening face of the recess 20 to the inner face thereof. Is about 1/3 of the length of the beam splitter 9.

To support the beam splitter 9 in the recess 20, first, the adhesive 23 is injected into the recess 20,
Next, one end of the beam splitter 9 is inserted into the recess 20, and the upper surface of the inserted end of the beam splitter 9 is pressed against the upper side surface 21 of the recess 20 and held.

Further, the upper side surface 21 of the recess 20 is formed so as to be oriented at an angle of 45 degrees with respect to both the optical axis of the laser diode 5 and the optical axis of the photodiode 7, as described above. , The beam splitter 9 is pressed into the concave portion 20.
The side surface 21 on the upper side of is used as a reference surface to restrict the mounting state.

In order to press the upper surface of the end of the inserted beam splitter 9 against the upper side surface 21 of the recess 20, for example, a thin plate member is placed in the gap between the lower surface of the beam splitter 9 and the lower side surface 22 of the recess 20. It is better to insert it.

Since one end of the beam splitter 9 in the lengthwise direction is supported by the base member 2 via the adhesive 23, the adhesive 23 is subject to changes such as shrinkage due to aging. Although distortion occurs in the bonded portion of the beam splitter 9, the portion other than the bonded portion, that is,
No distortion occurs in the portion where the laser beam is reflected or transmitted.

[0045]

As is apparent from the above description, the supporting structure of the parallel plate type optical component of the present invention has a base member and a parallel plate type optical component, and the base member has a smooth reference. A surface is formed, and the optical component is supported by the one surface of one end of the optical member in a state of being in contact with the reference surface of the base member.

Therefore, according to the supporting structure of the parallel plate type optical component of the present invention, since the supporting part of the parallel plate type optical component to the base member is only one end, the supporting part is supported. The generated distortion is generated only in the supporting portion, and no distortion occurs in the other portion, that is, the portion where the light is reflected or transmitted. Therefore, the accuracy of the optical component can be improved.

In the above embodiment, the support structure of the parallel plate type optical component of the present invention is applied to the support structure of the beam splitter of the optical pickup device. It can be applied to a support structure for an optical component.

Further, the specific shapes and structures shown in the above embodiments are merely examples of the embodiment for carrying out the supporting structure of the parallel plate type optical component of the present invention, and the present invention is realized by these. The technical scope of should not be construed in a limited way.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a first embodiment in which the supporting structure of a parallel plate type optical component of the present invention is applied to a supporting structure of a beam splitter of an optical pickup device together with FIG.

FIG. 2 is an exploded perspective view showing an enlarged main part.

FIG. 3 is an enlarged sectional view of an essential part showing a second embodiment in which the supporting structure of the parallel plate type optical component of the present invention is applied to the supporting structure of the beam splitter of the optical pickup device.

FIG. 4 is a sectional view showing an example of a conventional parallel plate type optical component support structure together with FIG.

FIG. 5 is an exploded perspective view showing an enlarged main part.

[Explanation of symbols]

 2 Base Member 9 Parallel Plate Type Optical Component 10 Spring Member 11 Recess 16 Reference Surface 20 Recess 21 Reference Surface 23 Adhesive

Claims (3)

[Claims] 1. A base member and a parallel plate type optical component, wherein a smooth reference surface is formed on the base member, and one flat surface at one end of the optical component is the reference surface of the base member. A supporting structure for a parallel plate type optical component, characterized in that it is supported in a state in which it is in contact with. 2. The support structure for a parallel plate type optical component according to claim 1, wherein one flat surface of one end of the optical component is pressed against the reference surface of the base member by a spring. 3. The support structure for a parallel plate type optical component according to claim 1, wherein one flat surface of one end of the optical component is bonded to a reference surface of the base member with an adhesive. ..