JPH04291033A - Mirror drive device - Google Patents

Abstract

PURPOSE:To prevent the distortion of a mirror and to prevent the face precision of the mirror from decreasing due to a difference of thermal expansion coefficient when a mirror inside a optical pickup is fixed. CONSTITUTION:When a mirror 1 is fixed to a mirror supporting member 2, the end part of a connection spring member is pressed against the side face of the mirror 1, adhesive is applied to the hole part provided at the end part of the connection spring member and the mirror 1 and the connection spring member are bonded to each other. Thus, the distortion of the mirror 1 caused by the difference of the thermal expansion coefficient between the mirror 1 and the mirror supporting member can be absorbed with the connection spring member, and the face precision of the mirror 1 can be maintained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and structure for preventing an increase in mirror aberration due to thermal stress in a mirror drive device existing in an optical pickup of an optical information recording/reproducing apparatus.

0002

[Prior Art] The conventional device is
As described in Publication No. 9, the mirror is directly adhesively fixed to the upper surface of the mirror holding member in an area smaller than the mirror area of the bottom surface of the mirror, or an uneven portion is provided on the upper surface of the mirror holding member, and an adhesive layer is applied only to this convex portion. The mirror is adhesively fixed to the mirror holding member through this adhesive layer, thereby reducing the amount of mirror deformation due to temperature changes.

However, in all of these conventional devices, the mirror and the mirror holding member are directly fixed via an adhesive layer, so it is particularly important that the mirror and the mirror holding member are made of different materials. In this case, the coefficients of thermal expansion of the two are different, so there is a difference in the amount of deformation between the two when the temperature changes, and this difference in the amount of deformation deforms the mirror, increasing aberrations that are optical distortions. becomes. Further, since the amount of increase in this aberration varies depending on the area and thickness of the adhesive layer, and the size of the mirror and mirror holding member, it is very difficult to maintain stable performance.

As described above, the conventional apparatus has the above-mentioned problems with respect to an increase in the amount of aberration of the mirror and maintenance of stable performance when the temperature changes.

[0005]

[Problems to be Solved by the Invention] As described above, in the prior art, the mirror and the mirror holding member are directly fixed via the adhesive layer, and the area of the adhesive layer is The difficulty of controlling the thickness has not been taken into consideration, and when the temperature changes, the material and size of the mirror and the mirror holding member are different, resulting in a difference in the amount of deformation between the two. There are problems in that the mirror is deformed and aberrations increase, and that stable performance cannot be maintained because the amount of aberration increase changes depending on the area, thickness, etc. of the adhesive layer, which is difficult to manage.

An object of the present invention is to ensure that even if the mirror and the mirror holding member are different in material and size, the amount of increase in aberration of the mirror when the temperature changes satisfies specifications, and that the mirror It is an object of the present invention to provide a mirror driving device having a structure capable of stably achieving performance in which the amount of aberration increase satisfies specifications.

[0007]

[Means for Solving the Problems] The above object does not directly fix the bottom surface of the mirror and the top surface of the mirror holding member through an adhesive layer, but instead fixes the bottom surface of the mirror and the top surface of the mirror holding member directly. This is achieved by indirectly fixing two or more arbitrary parts via an elastic material such as a spring material. The specific means is shown in FIG. In other words, the side surface of the mirror is made of an elastic material such as stainless steel, spring material, rubber material, or resin material, and by making the cross-sectional shape appropriate, the bending rigidity and torsional rigidity in each direction are appropriate. One end of the connecting spring member is fixed by adhesive or the like, and the other end is fixed to a part of the mirror holding member by adhesive or the like. Of course, there may be a plurality of these connecting spring members, and in the specific method shown in FIG. A structure is provided on two sides of the mirror for adhesively fixing the center portion of the member to the mirror holding member.

Furthermore, in order to obtain stable performance, a hole or notch is provided in the portion of the connecting spring member that contacts the mirror side surface, and an adhesive is applied from above the hole or notch. The amount of adhesive attached to the side surface of the mirror is kept constant. The specific means is shown in FIG. That is, a hole is provided in the end of the connection spring member pressed against the side surface of the mirror, and by applying an adhesive from above the connection spring member near this hole, the mirror can be fixed. A part of the side surface and the end of the connection spring are adhesively fixed.

[0009]

[Operation] The mirror and the mirror holding member each have a coefficient of thermal expansion unique to their materials, and therefore, when the temperature changes, the mirror and the mirror holding member each tend to deform independently. For example, when the temperature decreases, a mirror holding member whose coefficient of thermal expansion is larger than that of the mirror will shrink more than the mirror. At this time, as shown in FIG. 4, when the present invention is not applied, the mirror and the mirror holding member are directly adhesively fixed via the adhesive layer, so the mirror holding member holds the mirror. The amount of contraction of the mirror is greater than the amount of contraction when the mirror is in an unrestricted state, and as a result, the mirror surface becomes distorted and the aberration of the mirror increases beyond the specification. However, when the present invention is applied as shown in FIG. 3, since the mirror and the mirror holding member are fixed via the connecting spring member, the amount of contraction of the mirror holding member and the amount of contraction of the mirror are different. Even if there is a difference between , there is no force applied to the mirror that would cause the aberration of the mirror to exceed the specifications during deformation, and the mirror contracts by an amount that is approximately the same as the amount of contraction in the unrestrained state. will not be distorted and the amount of aberration of the mirror will not increase beyond the specification.

Further, the end of the connecting spring member pressed against the mirror side surface is provided with a hole, etc., and the mirror side surface and the end of the connecting spring member are adhesively fixed at this portion. The size of the material layer is always constant, so the above performance is
It will not become unmaintained due to the amount of adhesive between the mirror side surface and the end of the connecting spring member.

[0011]

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.
, will be explained with reference to FIGS. 5 and 6.

FIG. 1 is a top view of the movable part of the mirror drive device in one embodiment of the present invention, FIG. 2 is a detailed view of the adhesive portion between the end of the connecting spring member and the side surface of the mirror, and FIG. 3 is the book shown in FIG. FIG. 5 is a top view of the movable part of the mirror drive device in another embodiment of the invention, and FIG. 6 is a cross-sectional side view of the entire mirror drive device.

The mirror 1 is arranged on the mirror 1 mounting surface of the mirror holding member 2, and the end of the connecting spring member 3 is pressed against the side surface of the mirror 1. An adhesive 5 is applied to the hole 6 provided in the mirror 1, and the mirror 1 and the connecting spring member 3 are bonded and fixed. The hole portion 6 is provided at the end of the connection spring member 3, and the adhesive material 5 is applied to this portion.
By applying , the size of the adhesive layer between the side surface of the mirror 1 and the connecting spring member 3 is constant regardless of the amount of adhesive 5 applied. On the other hand, a part of the connecting spring member 3 adhesively fixed to the mirror 1 is
A protrusion or the like provided on the mirror holding member 2 is fixed to a part of the mirror holding member 2 by adhesive or the like. In this way, the mirror 1 is connected to the mirror via the connecting spring member 3.
It is indirectly connected to the holding member 2, and the mirror 1 can be displaced independently of the mirror holding member 2 in the X and Y directions in the figure on the mirror 1 mounting surface of the mirror holding member 2. The structure allows for The drive coil 4 is wound and fixed around the outer circumference of the mirror holding member 2, and the mirror 1, the mirror holding member 2, the connecting spring member 3, and the drive coil 4 constitute a movable part of the mirror drive device. ing. One end of the suspension 10 is fixed to the movable part with a fixing screw 11, and the other end of the suspension 10 is similarly fixed to the mirror drive device fixing part 9 with a fixing screw 11, so that the movable part and the fixed part of the mirror drive device are fixed. are connected to each other, and the movable part is structured to be rotatable about one axis. A magnet assembly consisting of a magnet 7 and a yoke 8 is disposed on the side of the drive coil 4, substantially parallel to the drive coil 4, as shown in FIG. As mentioned above, the mirror drive device is mainly composed of a movable part, a fixed part, and a magnet assembly.

Next, the operation will be explained. When a drive current flows through the drive coil 4 wound and fixed around the outer periphery of the mirror holding member 2, the magnetic flux flowing from the magnet 7 interacts with the drive current to generate electromagnetic force. Due to the electromagnetic force generated in the drive coil 4, the movable part of the mirror drive device rotates about one axis, and the light beam reflected by the mirror 1 is reflected in a predetermined direction. Next, the operation of the mirror when the temperature changes will be explained. Generally, the mirror 1 and the mirror holding member 2 are made of different materials and therefore have different coefficients of thermal expansion. The mirror holding member 2, which has a higher coefficient of thermal expansion than the mirror 1, deforms more than the mirror 1 when the temperature changes. Therefore, there is a difference in the amount of thermal deformation between the mirror 1 and the mirror holding member 2. Now consider the case where the temperature decreases. As shown in Fig. 3, since the thermal expansion coefficients of mirror 1 and mirror holding member 2 are different, there is a difference in the amount of contraction at both ends after the temperature change. -1
The gap between the mirror holding member 2 and the mirror holding member 2 becomes smaller after the temperature changes, and becomes L2 (<L1). In other words, there was a difference in the amount of contraction between the two by L1-L2. However, since the mirror 1 and the mirror holding member 2 are not directly connected but are connected via the connecting spring member 3 having appropriate bending rigidity, the difference in the amount of contraction between L1 and L2 is due to the difference in the amount of contraction of the connecting spring. Part 3
is absorbed by deformation, the mirror 1 simply slides on the mirror 1 mounting surface of the mirror holding member 2, and the connecting spring member 3 has appropriate bending rigidity. Even if the mirror 1 is deformed by the amount L1-L2, no large force is applied to the mirror 1. Therefore, mirror 1 is in almost the same state as if it were contracted in an unrestrained state, and even after a temperature change, mirror 1 does not undergo a large strain, so mirror 1
The amount of aberration will not increase and specifications will not be satisfied. Further, the size of the adhesive layer that connects the connecting spring member 3 and the side surface of the mirror 1 is determined by the size of the hole provided in the connecting spring member 3.
Since the adhesive material 5 is applied to the portion, it is constant, and therefore, there is no difference in the above-mentioned mirror operation even if the amount of the adhesive material 5 applied varies. On the other hand, when the present invention is not applied, the mirror 1 and the mirror holding member 2 are directly bonded via the adhesive layer 5 as shown in FIG. Due to the difference, mirror 1 is distorted, the aberration of mirror 1 increases, and specifications are no longer met.

As described above, according to this embodiment, the connecting spring member 3 having appropriate bending rigidity is connected to the mirror 1 and the mirror 1.
Because it is indirectly coupled to the holding member 2 and absorbs the difference in the amount of contraction or expansion between the mirror 1 and the mirror holding member 2 that occurs when the temperature changes, a large strain occurs in the mirror 1 when the temperature changes. This prevents the amount of aberration of the mirror 1 from failing to meet the specifications, which would have happened in the case where the present invention was not applied, as in the past. It is possible to always record and reproduce information on an optical disc without the aberration of mirror 1 increasing due to temperature changes and going out of specification, making it impossible to normally record and reproduce information on the optical disc. There is an effect. Furthermore, by providing the hole 6 at the end of the connecting spring member 3, the size of the adhesive layer between the side surface of the mirror 1 and the connecting spring member 3 is independent of the amount of adhesive 5 applied to this portion. Since this is constant, there is also the effect that the above effect can be achieved without being affected by the amount of adhesive 5 applied.

FIG. 5 shows a part of the side surface of the mirror 1.
The above-mentioned connecting spring member 3 is adhesively fixed to a protrusion etc. arranged on the holding member 2, and is attached to a side surface facing the side surface of the mirror 1.
Another example is shown in which .

[0017]

[Effects of the Invention] As explained above, according to the present invention,
Since the mirror is indirectly coupled to the mirror holding member via a connecting spring member having appropriate bending rigidity, the mirror can slide on the mirror mounting surface of the mirror holding member, and
Since the connecting spring member can absorb the difference in the amount of thermal deformation between the mirror and the mirror holding member, even if there is a difference in the amount of thermal deformation between the mirror and the mirror holding member during temperature changes, there will be no large distortion in the mirror. This has the effect of preventing the amount of aberration of the mirror from failing to meet the specifications.

Furthermore, by providing a hole or the like at the end of the connecting spring member and adhesively fixing the mirror and the connecting spring member in this portion, the size of the adhesive layer between the mirror and the connecting spring member is always maintained. Since the thickness is constant, the above-mentioned effect can always be produced regardless of the amount of adhesive applied.

[Brief explanation of the drawing]

FIG. 1 is a top view of a possible part of a mirror driving device showing an embodiment of the present invention.

FIG. 2 is a detailed view of the bonded portion between the end of the connecting spring member and the side surface of the mirror.

FIG. 3 is an operation diagram at low temperature in the embodiment of the present invention shown in FIG. 1;

FIG. 4 is an operation diagram at low temperature when the present invention is not implemented.

FIG. 5 is a top view of a movable part of a mirror drive device showing another embodiment of the present invention.

FIG. 6 is a cross-sectional side view of the entire mirror drive device.

[Explanation of symbols] 1...mirror, 2...Mirror holding member, 3...Connection spring member, 4... Drive coil, 5...adhesive material, 6... Hole of connecting spring member, 7...Magnet, 8...York, 9...Fixed part, 10...Suspension, 11...Fixing screw.

Claims (3)

[Claims] 1. A mirror holding member having appropriate rigidity, a mirror held by the mirror holding member, a drive coil and a driving magnetic circuit for driving the mirror, at least the mirror and the mirror. It consists of a spring member made of an elastic body or the like that connects a movable part made of a mirror holding member and a fixed part, and the movable part is capable of rotational movement in at least one axial direction or translational movement in at least one direction. In the mirror drive device having such a structure, at least a portion of at least one side of the mirror and at least a portion of the mirror holding member are made of stainless steel, resin, rubber, or the like having appropriate rigidity in each direction. 1. A mirror drive device characterized in that the mirror drive device is connected via a connection spring member made of an elastic body or a spring material. 2. A portion of one side of the mirror is attached to the mirror.
The connecting spring member is fixed to a part of the holding member by adhesive or the like, at least one end of the connecting spring member is fixed by adhesive or the like to a side surface facing the one side of the mirror, and the other end of the connecting spring member is fixed to the mirror holding member. 2. The mirror drive device according to claim 1, wherein the mirror drive device is fixed to the member by adhesive or the like. 3. The connecting spring member according to claim 1 or 2, wherein the connecting spring member is provided with a notch, a hole, or a slit in the vicinity of the connecting portion with the mirror, such as at the end of the connecting spring member or near the end. A mirror drive device characterized by being arranged as follows.