JPH0433542Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The invention consists of a light projection system housing to which optical components that generate a beam of light to be incident on an objective lens are attached, an actuator that drives the objective lens, and an actuator that detects reflected light. The present invention relates to an optical head configured to be fixed to a base housing to which an optical component is attached by pressure contact with the tightening force of a screw.

(Prior Art) Optical heads are used to record information on video discs, compact discs, etc., and to reproduce information from these discs. FIG. 5 is a block diagram mainly showing an example of the optical system (in this example, the reading optical system) of the optical head. In the figure, reference numeral 11 denotes a semiconductor laser that emits a laser beam, and the output beam of the semiconductor laser 11 is converted into a parallel beam by a collimator lens 12 and enters a half mirror 13. The beam incident on the half mirror 13 passes through the half mirror 13, is focused by the objective lens 14, and forms a spot on the disk 15. The reflected beam from the disk 15 travels backward through the objective lens 14 to become a parallel beam and enters the half mirror 13. A part of it is reflected by the half mirror 13 and the condensing lens 1
6 and a cylindrical lens 17 to connect a spot on the four-divided light receiving element 18. In compact disc players, etc., this four-part light receiving element 18
Signals for reading recorded data, focusing, and tracking are obtained from the four output signals. In recent years, there has been a strong demand for miniaturization of optical heads having the above-mentioned configuration, and a thinner optical system has appeared, as shown in FIG. In this figure, the same parts as in FIG. 5 are given the same reference numerals. FIG. 6A shows a front view, and FIG. 6B shows a plan view. In this optical system, the optical path is bent approximately 90 degrees by mirror 19, and the sixth
We are trying to make it thinner in the vertical direction in Figure A. Optical components constituting such a thin optical head have conventionally been attached to a light projection system housing and a base housing as shown in FIGS. 3 and 4.

3 and 4, reference numeral 2 denotes a cylindrical light projection system housing to which the semiconductor laser 11, collimator lens 12, half mirror 13, and mirror 19 shown in FIG. 6 are attached. Further, 3 is an actuator that drives the objective lens 14 for focusing and tracking, and 4 is a condenser lens 16, a cylindrical lens 17, and a light receiving element 18 in FIG.
is disposed in the side portion 4g, and the actuator 3 is disposed on the upper portion of the base housing, which has a gate-shaped cross section. The inner surface of the gate-shaped base housing 4 has a fourth
As shown in the figure, a horizontal surface 4a, two vertical surfaces 4
b, 4c, and planes 4d, 4e connecting the horizontal plane 4a and the vertical planes 4b, 4c. As shown in FIG. 3, a flange portion 2a is provided on one end surface of the lighting system housing 2, and the cylindrical portion has a notch portion 2b cut out by about 1/2 from the top and about 1/4 from the side. A notch 2c is provided. Although not shown, the semiconductor laser 11 in FIG. 6 is attached to the through hole in the end face on the side of the flange 2a, the mirror 19 is attached near the notch 2b, and the half mirror 13 is attached near the notch 2c. It is being Further, a screw hole 5 is bored at the top of the outer periphery of the light projection system housing 2, near the flange portion 2a. A hole 6 is bored in the upper surface of the gate-shaped base housing 4. The circumferential surface of the light projecting system housing 2 is in contact with the inner surface planes 4d and 4e of the gate-shaped base housing 4, and the flange portion 2a is in contact with the end surface of the base housing 4. screw 7
passes through the hole 6 of the base housing 4 and is screwed into the screw hole 5 of the light projection system housing 2, whereby the light projection system housing 2 is fixed to the base housing 4 under pressure, thereby forming an optical head. and,
In the light projection system housing 2, the semiconductor laser 11
The laser beam emitted from the collimator lens 1
2. Pass through half mirror 13 and abbreviate at mirror 19
The light is bent at 90°, exits from the notch 2b, and enters the objective lens 14 disposed on the upper part of the base housing 4. Also, the reflected beam on the disk 15 reverses the above path, changes its course by 90 degrees at the half mirror 13, exits from the side notch 2c, and enters the condenser lens 16 on the side 4g of the base housing 4. The light then passes through the cylindrical lens 17 and enters the four-part light receiving element 11 .

According to the above configuration, the screw 7 is inserted into the screw hole 5.
By screwing the projection system housing 2 into the base housing 4, the outer peripheral side of the projection system housing 2 comes into line contact with the flat surfaces 4d and 4e of the base housing 4, and the flat surface perpendicular to the axis. The flange portion 2a contacts the end face of the base housing 4, thereby positioning the base housing 4 in the axial direction.

(Problems to be Solved by the Invention) In this type of optical head, the laser beam crosses between the optical system housing 2 and the base housing 4 at the notches 2b and 2c. Installation accuracy is an important factor. In the conventional optical head as described above, axial positioning is performed by contact between the flange portion 2a and the end face of the base housing 4, but positioning in the plane direction perpendicular to the axis is performed by line contact at two locations. There is. However, since the hole 6 through which the screw 7 passes is a blank hole, there is nothing to restrict the rotation of the projection system housing 2 (in the direction of the arrow in Figures 3 and 4) during assembly, so it may deviate from its normal position. There was a problem in that the projection system housing 2 was sometimes screwed onto the base housing 4 in a tilted state, and it was necessary to adjust the rotation of the projection system housing 2 later.

The present invention was devised in view of these problems, and its purpose is to realize an optical head that does not require rotational adjustment of the light projection system housing.

(Means for Solving the Problems) The present invention for solving the above-mentioned problems combines a light projecting system housing to which an optical component that generates a beam of light to be incident on an objective lens is attached, an actuator that drives the objective lens, and an actuator that drives the reflected light. In an optical head configured to be fixed to a base housing to which an optical component to be detected is attached by pressure contact with the tightening force of a screw, a first housing perpendicular to the axial direction is attached to one of the light projection system housing and the base housing. The other housing is provided with a fourth plane that abuts the first plane, and two second and third planes perpendicular to the first plane that intersect with each other. 2. Providing a fifth plane that makes surface contact with one of the third planes and a convex surface that makes line contact with the other plane, and presses the surface contact portion and the contact portion when tightening the screw. The screwing position of the light projecting system housing and the base housing is selected so that a force is applied.

(Function) In the optical head of the present invention, the projection system housing and the base housing are positioned in a plane perpendicular to the axial direction by both plane contact and line contact.

(Example) Hereinafter, an example of the present invention will be described in detail using FIGS. 1 and 2. In these figures, the same parts as in the conventional example described above are given the same reference numerals. The light projection system housing 2 in this embodiment has a flat block 8 on the top (plane) of its outer periphery, and the upper plane of the flat block 8 is in surface contact with the flat surface 4a of the base housing 4. When the outer peripheral side (cylindrical surface) of 2 comes into line contact with the flat surface 4c, the projection system housing 2 assumes a normal position with respect to the base housing 4 (in this case, the axial direction is only in the perpendicular plane direction). . Also in this embodiment, the flange portion 2a of the light projecting system housing 2 is in contact with the end surface of the base housing 4. Furthermore, in this embodiment, the hole 6 is shaped like the one shown in FIG. It is drilled in the upper right plane 4e, and a screw hole 5 is also provided at a position opposite to this. Further, the outer surface of the base housing 4 is provided with an inclined surface 4 so that the head of the screw 7 can stably abut.
f is provided.

According to the above configuration, the projection system housing 2 is pressed against the base housing 4 in the axial direction, and the screw 7 is screwed into the screw hole 5 while the flange portion 2a is pressed against the end surface of the base housing 4. When it is tightened, the projection system housing 2 is drawn into the base housing 4, the flat block 8 comes into contact with the flat surface 4a, and the outer peripheral side of the projection system housing comes into contact with the flat surface 4c. At this time, even if the projection system housing 2 comes into contact with the base housing 4 in a state where it has been rotated and deviated from its original normal position, as the screws 7 are tightened, a force is applied to the contact portion to press the two together, and this Due to the rotation moment generated by the pressure contact force, the projection system housing 2 rotates to a position where the flat block 8 and the flat surface 4a are in firm surface contact, and then returns to the normal position. Further, by tightening the screw 7, the outer circumferential side of the light projection system housing 2 is brought into firm line contact with the flat surface 4c by pressure contact force. Therefore, since the positioning in the plane direction perpendicular to the axial direction is performed accurately, rotational adjustment of the light projecting system housing 2 is not necessary. Of course, alignment in the axial direction is not necessary since both are in contact from the beginning.

Note that the present invention is not limited to the above embodiments. For example, in the above explanation, the planar contact for rotation regulation was made between the planar block 8 provided at the top of the light projection system housing 2 and the plane 4a, but in FIG. The plane block 8 may be provided on the circumferential surface of the light projection system housing 2 so as to be in contact with one plane. Alternatively, a flat surface may be formed directly on the light projection system housing 2 without separately providing the flat block 8. Further, in the above explanation, the plane contact surface 4a and the line contact surface 4c are perpendicular to each other, but if the angle formed by the two surfaces is within 180°, a force for tightening the screw will be generated, so even if the structure is configured in this way. good.
Further, the line contact portion of the housings 2 and 4 may have a convex surface (not limited to a circumferential surface) on the base housing 4 side.

(Effects of the invention) As explained above, the optical head of the invention has
Since the light emitting system housing and the base housing are in line contact and in planar contact, and pressure force is applied to both contact portions, rotational adjustment of the light emitting system housing is not necessary.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention;
The figures are a sectional view taken along the line AA in FIG. 1, FIG. 3 is a perspective view showing a conventional optical head, FIG. 4 is a sectional view taken along BB in FIG. It is an explanatory diagram of an optical system. 2... Light projection system housing, 2a... Flange portion, 3... Actuator, 4... Base housing, 4a, 4b, 4c, 4d, 4e... Plane,
5...screw hole, 6...idiot hole, 7...screw, 8...
...Flat block.

Claims (1)

[Scope of utility model registration request] The projection system housing, to which the optical component that generates the light flux that is incident on the objective lens is attached, is fixed by pressure with the tightening force of the screw to the base housing, to which the actuator that drives the objective lens and the optical component that detects the reflected light are attached. In the optical head configured as above, one of the light projection system housing and the base housing has a first plane perpendicular to the axial direction, and two second planes perpendicular to the first plane that intersect with each other. A third flat surface is provided on the other housing, and the other housing has a fourth flat surface that contacts the first flat surface, and a fifth flat surface that makes surface contact with one of the second and third flat surfaces. A screw thread between the light projection system housing and the base housing is provided so that a flat surface and a convex surface in line contact with the other flat surface are provided, and a pressure force is applied to the surface contact portion and the line contact portion when the screw is tightened. An optical head characterized by a selected landing position.