JP2008275829A - Deformable mirror, method of manufacturing same, and optical pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deformable mirror in which the occurrence of local deformation on a mirror surface is suppressed and the operation efficiency of piezoelectric actuators is excellent. <P>SOLUTION: The deformable mirror 1 includes: a base 2; a mirror substrate 3 which is arranged facing to the base 2 and has a mirror surface 3a formed on the surface thereof at the side opposite from the surface facing to the base 2; columns 4 which are arranged on the base 2 and support the mirror substrate 3; and piezoelectric actuators 5 which have a piezoelectric bodies which are expanded and contracted by applying an electric voltage thereto, are arranged on the base 2 and displace movable parts of the mirror substrate 3 which are not connected to the columns 4 of the mirror substrate 3. An adjustment member 8 for height adjustment made of a material different from that of the piezoelectric body is connected to the end part facing to the mirror substrate 3 of the piezoelectric actuators 5. The adjustment member 8 is made of the same material as that of the end part of the columns 4 which is connected to the mirror substrate 3, and the mirror substrate 3 and the adjustment member 8 are not connected to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable shape mirror that is provided so that the shape of a mirror surface can be deformed, and more particularly to a variable shape mirror that can change the shape of a mirror surface by expansion and contraction of a piezoelectric actuator. The present invention also relates to a method for manufacturing such a deformable mirror. Furthermore, the present invention relates to an optical pickup device provided with such a deformable mirror.

  Conventionally, various proposals have been made on variable shape mirrors that modify the shape of the mirror surface and correct optical distortion or the like of an incident light beam. For example, optical disk devices, video projectors, digital cameras, and other optical devices such as optical cameras have been proposed. It is attracting attention in the field.

  Specifically, for example, in the field of optical pickup devices, as shown in Patent Documents 1 to 5, frames generated when recording and reproducing optical disks such as CDs (compact disks) and DVDs (digital versatile disks) are performed. A technique using a deformable mirror has been proposed to correct wavefront aberration such as aberration and spherical aberration. Note that the coma aberration is an aberration generated when the disk surface of the optical disk is tilted with respect to the optical axis, and the spherical aberration is a thickness of a transparent resin (protective layer) mainly protecting the recording surface of the optical disk. This aberration is caused by the difference.

  Such a deformable mirror is formed by laminating a thin film such as a unimorph or bimorph deformable mirror using a piezoelectric element as disclosed in Patent Document 1 or a piezoelectric film as disclosed in Patent Document 2. There is a deformable mirror. However, in the case of the deformable mirror shown in Patent Document 1 or Patent Document 2, there is a problem that it is not easy to increase the amount of deformation of the mirror surface.

  As a variable shape mirror different from Patent Documents 1 and 2, as shown in Patent Documents 3 to 5, the vertical direction of a piezoelectric element (piezoelectric actuator) formed in a columnar shape (direction orthogonal to the mirror surface provided in the variable shape mirror) There is a deformable mirror that deforms a mirror surface by using expansion and contraction. FIG. 5 is a schematic cross-sectional view showing a configuration of a conventional deformable mirror 100 as shown in Patent Documents 3 to 5, and FIG. 5 (a) shows a state where the mirror surface 102a is not deformed, and FIG. ) Shows a state in which the mirror surface 102a is deformed.

  As shown in FIG. 5, the conventional deformable mirror 100 includes a base 101, a mirror substrate 102 that is disposed to face the base 101 and has a mirror surface 102 a on the surface opposite to the surface facing the base 101, and the base 101. And a piezoelectric actuator 104 which is disposed on the base 101 and displaces a movable portion surrounded by a portion joined to the column 103 of the mirror substrate 102 by expansion and contraction. ing.

For example, when the piezoelectric actuator 104 is extended, the mirror substrate 102 is displaced as shown in FIG. 5B, whereby the mirror surface 102a is deformed. In the case of such a configuration, there are advantages that a large deformation of the mirror surface 102a is easily obtained and manufacture is easy as compared with a variable shape mirror formed by laminating thin films.
JP 2004-109562 A JP 2005-196859 A JP 2006-302389 A JP 2006-302390 A JP 2006-351154 A

  However, the conventional deformable mirror 100 that deforms the mirror surface using the expansion and contraction of the piezoelectric actuator in the vertical direction has the following problems.

  When the mirror substrate 102 and the piezoelectric actuator 104 are joined, local distortion occurs in the mirror surface 102a of the mirror substrate 102 due to the influence of an adhesive or the like used at the time of joining. In this case, the direction of the reflected light is not a desired direction for a portion where local distortion has occurred. For this reason, even if the deformable mirror 100 is used, there arises a problem that optical distortion cannot be sufficiently corrected.

  In consideration of this point, it is preferable not to join the mirror substrate 102 and the piezoelectric actuator 104. In this case, however, a gap d is generated between the mirror substrate 102 and the piezoelectric actuator 104 as shown in FIG. There is. This occurs for the following reason.

  Since the support pillar 103 and the piezoelectric actuator 104 constituting the deformable mirror 100 are usually made of different materials, they are prepared separately. At this time, the strut 103 and the piezoelectric actuator 104 are prepared to have the same height so that the mirror surface 102a is smooth when no voltage is applied to the piezoelectric actuator 104.

  However, due to variations in manufacturing, variations in the heights of the columns 103 and the piezoelectric actuators 104 usually occur. For this purpose, a polishing process is performed so that the heights of the support pillar 103 and the piezoelectric actuator 104 are equal. At this time, since the support column 103 and the piezoelectric actuator 104 are formed of different materials, a difference occurs in the processing rate during polishing. For example, when the hardness of the piezoelectric actuator 104 is smaller than the hardness of the support column 103, the height of the piezoelectric actuator 104 is lower. In this case, in the deformable mirror 100 finally obtained, a gap d is generated between the mirror substrate 102 and the piezoelectric actuator 104.

  When the gap d is generated, for example, when the piezoelectric actuator 104 is extended to deform the mirror substrate 102, the gap d does not contribute to the deformation of the mirror substrate 102 even if the piezoelectric actuator 104 is extended. It becomes. For this reason, when the mirror substrate 102 is deformed, it is necessary to increase the voltage applied to the piezoelectric actuator 104, and the operation efficiency is deteriorated. In some cases, the mirror surface 102a cannot be sufficiently deformed.

  If the hardness of the piezoelectric actuator 104 is higher than that of the column 103, the piezoelectric actuator 104 is higher than the column 103. In this case, in the finally obtained deformable mirror 100, the mirror There is a possibility that local distortion occurs in the mirror surface 102a of the substrate 102, and this also causes a problem.

  Further, if the support 103 is made of the same material as that of the piezoelectric actuator 104, the processing rate of the support 103 and the piezoelectric actuator 104 at the time of polishing becomes the same, and the heights of both can be made uniform. This causes a problem that the manufacturing cost of the deformable mirror increases because a large amount of high-cost piezoelectric actuators are used.

  In view of the above problems, an object of the present invention is to suppress the occurrence of local distortion on a mirror surface in a deformable mirror that can change the shape of the mirror surface by expansion and contraction of the piezoelectric actuator. The object is to provide a deformable mirror with good operating efficiency. Another object of the present invention is to provide a method for manufacturing such a deformable mirror. Furthermore, another object of the present invention is to provide an optical pickup device that can appropriately read and write information with low power consumption by providing such a deformable mirror.

  In order to achieve the above object, the present invention provides a base, a mirror substrate disposed opposite to the base, and having a mirror surface formed on a surface opposite to the surface facing the base, and disposed on the base. A support that supports the mirror substrate; a piezoelectric actuator that has a piezoelectric body that expands and contracts by applying a voltage; and is disposed on the base and displaces a movable portion that is not joined to the support of the mirror substrate; and In the variable shape mirror, the height adjustment member made of a material different from that of the piezoelectric body is joined to an end portion of the piezoelectric actuator that faces the mirror substrate. The end portion to be joined to the mirror substrate is made of the same material, and the mirror substrate and the adjusting member are not joined.

  According to this structure, since it is the structure which does not join the adjustment member joined to a mirror board | substrate and a piezoelectric actuator, it is possible to suppress the local distortion which generate | occur | produces in a mirror surface. In addition, since the end portion joined to the mirror substrate of the support and the adjustment member joined to the end facing the mirror substrate of the piezoelectric actuator are made of the same material, the support and the piezoelectric actuator (the adjustment member is joined). It is easy to align the height). For this reason, even when the mirror substrate and the adjustment member are not joined, the generation of a gap between the mirror substrate and the piezoelectric actuator (which indicates that the adjustment member is joined) can be suppressed. The operating efficiency can be improved. Furthermore, since the struts are not made of the same material as that of the piezoelectric actuator, the manufacturing cost of the variable shape mirror capable of obtaining the above effect can be kept low.

  According to the present invention, in the deformable mirror having the above-described configuration, the support column may be formed of the same material from an end portion joined to the mirror substrate to an end portion joined to the base.

  According to this configuration, it is not necessary to manufacture the support columns by bonding members made of different materials, and the work burden when manufacturing the deformable mirror can be reduced.

  In order to achieve the above object, the present invention is arranged on a base, a mirror substrate disposed opposite to the base and having a mirror surface on a surface opposite to the surface facing the base, and the base. A piezoelectric actuator having a support that supports the mirror substrate and a piezoelectric body that expands and contracts when a voltage is applied, and is disposed on the base and displaces a movable part that is not joined to the support of the mirror substrate. And an adjustment member for height adjustment made of the same material as the end portion of the pillar to be joined to the mirror substrate at the end portion of the piezoelectric actuator facing the mirror substrate. And simultaneously polishing the piezoelectric actuator having the support and the adjustment member joined to the base while being joined to the base. It is characterized by a door.

  According to this configuration, at the time of manufacturing the deformable mirror, the columns of the deformable mirror and the piezoelectric actuator (when the adjustment member remains even after the polishing is finished, the height of the piezoelectric actuator is also included) are included. It is easy to align the thickness by polishing. For this reason, even when the mirror substrate and the piezoelectric actuator are not joined, it is possible to provide a variable shape mirror with good operating efficiency of the piezoelectric actuator.

  In addition, the present invention is an optical pickup device including the shape variable mirror having the above-described configuration.

  According to this configuration, the deformable mirror provided in the optical pickup device has good operation efficiency of the piezoelectric actuator while suppressing local distortion generated on the mirror surface. For this reason, the wavefront aberration generated in the optical system of the optical pickup device can be appropriately corrected with low power consumption by the variable shape mirror. That is, it is possible to provide an optical pickup device that can appropriately read and write information with low power consumption.

  According to the present invention, in a variable shape mirror whose shape of the mirror surface can be deformed by expansion and contraction of the piezoelectric actuator, it is possible to suppress the occurrence of local distortion on the mirror surface, and the piezoelectric actuator can be operated efficiently. Can provide. Further, according to the manufacturing method of the present invention, such a deformable mirror can be easily manufactured. Furthermore, according to the present invention, it is possible to provide an optical pickup device that can appropriately read and write information with low power consumption.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, embodiment shown here is an example and this invention is not limited to embodiment shown here. Each drawing is drawn so that the contents of the present invention can be easily understood, and the size, thickness, and the like of each member in the drawing do not necessarily match the actual configuration.

  FIG. 1 is a schematic perspective view showing the configuration of the deformable mirror according to the present embodiment. For convenience of explanation, only the mirror substrate is disassembled. 2 is a cross-sectional view taken along the line AA in FIG. The configuration of the variable shape mirror of this embodiment will be described with reference to FIGS. 1 and 2.

  Reference numeral 1 denotes a deformable mirror, a mirror surface of which is deformably provided, and is a device used for correcting optical distortion of an incident light beam. The deformable mirror 1 includes a base 2, a mirror substrate 3 disposed opposite to the base 2, a support column 4 disposed on the base 2 to support the mirror substrate 3, and disposed on the base 2 to expand and contract. And the piezoelectric actuator 5 for displacing the mirror substrate 3 to deform the mirror surface 3a of the mirror substrate 3. Hereinafter, each part will be described in detail.

  The base 2 plays a role of supporting the support column 4 and the piezoelectric actuator 5. The base 2 is composed of an insulating member, and is formed of, for example, glass or ceramics. On the base 2, a wiring pattern 6 including an electrode 7 for supplying power to the piezoelectric actuator 5 is formed. The wiring pattern 6 is formed, for example, by forming a silicon (Si) pattern on a glass substrate and depositing a metal such as gold (Au) on the silicon pattern.

  The mirror substrate 3 is disposed so as to be substantially parallel to the base 2, and a mirror surface 3 a is formed on the surface opposite to the surface facing the base 2. The mirror substrate 3 has a movable portion that is displaced by expansion and contraction of the piezoelectric actuator 5, and is configured such that the mirror surface 3a of the mirror substrate 3 is deformed in accordance with the displacement of the movable portion.

  Here, the movable part of the above-described mirror substrate 3 will be described. The mirror substrate 3 is joined to the support column 4 as will be described later. For this reason, although the part joined with the support | pillar 4 is not displaced, about the area | region enclosed by the part joined by this support | pillar 4, it can displace by applying force. That is, in the mirror substrate 3 included in the deformable mirror 1 of the present embodiment, a region surrounded by a portion joined by the support column 4 corresponds to the movable portion.

  The mirror substrate 3 needs to be thin to some extent so as to be displaced by the expansion and contraction of the piezoelectric actuator 5. Further, the mirror substrate 3 needs to be formed of a rigid material because it is difficult to be destroyed due to deformation accompanying expansion and contraction of the piezoelectric actuator 5. Considering such points, in the present embodiment, the mirror substrate 3 is formed of a silicon (Si) substrate. However, the substance constituting the mirror substrate 3 is not limited to silicon, and other substances may be used as long as they can be thinned and have rigidity.

  The mirror surface 3 a of the mirror substrate 3 is obtained, for example, by forming an aluminum (Al) layer on the mirror substrate 3. The Al layer is formed by a method such as vapor deposition or sputtering. The mirror surface 3a is not limited to aluminum, and may be, for example, gold (Au), silver (Ag), or the like as long as it can obtain a desired reflectance with respect to the reflected light of the light beam incident on the mirror surface 3a of the deformable mirror 1. Various modifications are possible. In the present embodiment, the entire upper surface of the mirror substrate 3 is configured as the mirror surface 3a. However, the present invention is not limited to this, and the region of the mirror surface 3a is determined in consideration of the incident diameter of the incident light beam. A configuration in which a reflective layer is formed only on that portion may be used.

  The support column 4 is disposed on the base 2 and plays a role of supporting the mirror substrate 3. In the present embodiment, the pillars 4 are provided at the four corners of the mirror substrate 3 and the central part of each side of the mirror substrate 3 formed in a rectangle (position between two of the pillars 4 disposed at the four corners). The mirror substrate 3 is supported at a total of eight locations. In addition, about the arrangement | positioning of the support | pillar 4, it is not the meaning limited to the structure of this embodiment, A various change is possible according to the objective.

  In this embodiment, the support | pillar 4 consists of the 1st area | region 4a and the 2nd area | region 4b which are comprised with a different material. The first region is a region including an end portion joined to the base 2 and is formed of, for example, glass. On the other hand, the second region 4b is a region including an end portion joined to the mirror substrate 3, and is formed of, for example, silicon. The first region 4a and the second region 4b are joined with an adhesive such as an epoxy resin, for example.

  The reason why the pillar 4 is made of the two regions 4a and 4b made of different materials is to make it easy to align the height of the pillar 4 and the piezoelectric actuator 5. This point will be described later. In addition, when the height of the support | pillar 4 and the piezoelectric actuator 5 is not equal, there exists a problem that the operating efficiency of the piezoelectric actuator 5 worsens or local distortion generate | occur | produces as mentioned above. The purpose is to eliminate.

  In the present embodiment, the joining between the support column 4 and the base 2 and the joining between the support column 4 and the mirror substrate 3 are both performed by interposing a metal layer (for example, an Au layer) as a joining layer between the joining members. For example, the bonding is performed by applying pressure at a high temperature of 400 ° C. to 550 ° C. (thermocompression bonding method). However, these bonding may be performed using an adhesive.

  The piezoelectric actuator 5 has a piezoelectric body that expands and contracts when a voltage is applied. A unit composed of this piezoelectric body and two internal electrodes (a positive electrode and a negative electrode) arranged so as to sandwich the piezoelectric body is one unit, and a laminated piezoelectric actuator formed by laminating these units, This is the piezoelectric actuator 5 of the present embodiment. Since the configuration of the multilayer piezoelectric actuator is well known, its detailed configuration is omitted here.

In the present embodiment, the laminated piezoelectric actuator is used because it is easy to obtain a large displacement. However, a piezoelectric actuator that is not a laminated type may be used. As the type of the piezoelectric body constituting the piezoelectric actuator 5, for example, include piezoelectric ceramics such as barium titanate (BaTiO ₃₎ or lead zirconate titanate _{(Pb (Zr x Ti 1-} x) O 3) However, the type is not particularly limited. In this embodiment, lead zirconate titanate having excellent piezoelectric characteristics is used.

  The piezoelectric actuator 5 is disposed on an electrode 7 (consisting of two electrodes, a positive electrode and a negative electrode) formed on the base 2, thereby enabling power supply. In the present embodiment, the piezoelectric actuator 5 is disposed on the inner side of the support column 4 disposed on the outer peripheral side of the mirror substrate 3 with respect to the mirror substrate 3. Four piezoelectric actuators 5 are arranged on the base 2 in the cross direction, and the piezoelectric actuators 5 facing each other are arranged so as to be symmetrical with respect to an axis passing through the center of the mirror surface 3a and orthogonal to the mirror surface 3a.

  The reason why the piezoelectric actuators 5 are arranged in this way is that the number of piezoelectric actuators 5 is not excessively increased and the mirror surface 3a can be easily deformed in a well-balanced manner. However, the arrangement and number of the piezoelectric actuators 5 are not limited to this configuration, and various changes can be made.

  The piezoelectric actuator 5 and the base 2 may be joined by a thermocompression bonding method in which pressure is applied at a high temperature (for example, 400 ° C. to 550 ° C.) with a metal layer (for example, Au layer) interposed, or an adhesion A method using an agent may be used.

  Further, in the piezoelectric actuator 5 of the present embodiment, a height adjusting adjusting member 8 made of a material different from the piezoelectric body is bonded to an end portion facing the mirror substrate 3 with an adhesive such as an epoxy resin. Yes. And the material which comprises this adjustment member 8 is the same material (silicon in this embodiment) as the material which comprises the 2nd area | region 4b of the support | pillar 4. As shown in FIG. This is in order to make the heights of the support column 4 and the piezoelectric actuator 5 easier to align, which will be described later.

  The adjustment member 8 bonded to the piezoelectric actuator 5 is not bonded to the mirror substrate 3. This is to reduce the occurrence of local distortion on the mirror surface 3 a of the mirror substrate 3.

  Next, a method for manufacturing the variable shape mirror 1 of the present embodiment will be described. In addition, the manufacturing method shown here is an example, and is not necessarily limited to this procedure.

  First, a silicon substrate is bonded to the glass substrate serving as the base 2 by anodic bonding. Next, the silicon substrate bonded to the glass substrate by anodic bonding is processed using a lithography method so that a desired silicon pattern is formed. A conductive layer (for example, an Au layer) is formed on the formed silicon pattern by a vapor deposition method, a sputtering method, or the like. Thereby, the wiring pattern 6 including the electrode 7 is formed on the base 2.

  In the present embodiment, when forming the Au layer on the silicon pattern, the Au layer is also formed at the position where the support column 4 on the base 2 is disposed. This is because the support columns 4 are joined by the above-described thermocompression bonding method.

  In parallel with the above-described process of forming the wiring pattern 6 on the base 2, the support 4 and the piezoelectric actuator 5 are prepared. First, the preparation process of the support | pillar 4 is demonstrated. A portion (for example, made of glass) that forms the first region 4a and a portion (for example, made of silicon) that forms the second region 4b of the support column 4 are cut out to a predetermined size. And both are joined with the adhesive agent which consists of epoxy resins etc.

  Next, a preparation process for the piezoelectric actuator 5 will be described. The piezoelectric actuator 5 is also formed to have a predetermined size. Further, the adjustment member 8 (for example, made of silicon) disposed at the end of the piezoelectric actuator 5 on the side facing the mirror substrate 3 is also cut out to a predetermined size. Then, the adjustment member 8 is joined to the piezoelectric actuator 5 with an adhesive made of, for example, an epoxy resin.

  The prepared support column 4 and piezoelectric actuator 5 (with the adjusting member 8 bonded) are bonded to a predetermined position of the base 2. At this time, the first region 4 a is joined to the base 2 for the support column 4. In the present embodiment, the bonding method is configured to be bonded by the above-described thermocompression bonding method. However, it may be joined with an adhesive.

  The post 4 and the piezoelectric actuator 5 (joined with the adjusting member 8) joined to the base 2 have the same height by polishing. At this time, what is polished is the second member 4b of the support column 4 and the adjusting member 8 joined to the piezoelectric actuator 5, both of which are composed of the same material (both are silicon in this embodiment). For this reason, the heights of the two can be accurately aligned without causing a difference in processing rate during polishing as described above.

  In this polishing step, any one of the adjustment member 8 joined to the second region 4b of the support column 4 and the piezoelectric actuator 5 is replaced with the support column 4 and the piezoelectric actuator 5 (when the adjustment member 8 remains by polishing, It is also possible to assume a state in which the piezoelectric actuator including the adjusting member 8 is eliminated at the same time. However, it is difficult to provide the second region 4b of the support column 4 and the adjustment member 8 aiming at such a state, and the support column 4 has a thickness larger than the thickness estimated to be polished. The second region 4b and the adjustment member 8 are provided.

  When the polishing of the support column 4 and the piezoelectric actuator 5 (expressed including the adjustment member 8) is completed, the mirror substrate 3 and the support column 4 are joined, and the variable shape mirror 1 is completed. The bonding at this time may be performed by the above-described thermocompression bonding method, or may be performed by an adhesive or the like.

  The variable shape mirror 1 of this embodiment is generated on the mirror surface 3a of the mirror substrate 3 because the mirror substrate 3 and the adjustment member 8 that is bonded to the end of the piezoelectric actuator 5 facing the mirror substrate 3 are not bonded. Local distortion can be reduced. And since the height of the support | pillar 3 and the piezoelectric actuator 5 (it represents including the adjustment member 8) can be arrange | equalized, a clearance gap generate | occur | produces between the piezoelectric actuator 5 and the mirror board | substrate 3, or the mirror surface 3a is extra. Generation of a large distortion can be suppressed as much as possible. For this reason, the deformable mirror 1 of the present embodiment can suppress the occurrence of local distortion on the mirror surface, and the operation efficiency of the piezoelectric actuator 5 is good.

  In the variable shape mirror 1 of the embodiment described above, the support column 4 is configured by the first region 4a and the second region 4b having different constituent materials. However, the present invention is not limited to this configuration. That is, as shown in FIG. 3, the entire support 4 may be formed of the same material. In this case, the adjustment member 8 joined to the piezoelectric actuator 5 is made of the same material (for example, silicon) as the support 4. And since the process of providing the 1st area | region 4a and the 2nd area | region 4b about the support | pillar 4 and joining them becomes unnecessary, work efficiency becomes good. In addition, FIG. 3 is explanatory drawing for demonstrating the modification of the shape variable mirror 1 of this embodiment.

  Next, an optical pickup device using the deformable mirror 1 of the present embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram showing the configuration of the optical system of the optical pickup device of this embodiment. The optical pickup device 10 is a device that enables reading of information and writing of information by irradiating the optical disc 20 with laser light.

  The optical pickup device 10 includes a semiconductor laser 11, a collimator lens 12, a beam splitter 13, a variable shape mirror 1, a quarter wavelength plate 14, an objective lens 15, a condenser lens 16, and a photodetector 17. And.

  Laser light emitted from the semiconductor laser 11 is converted into parallel light by the collimator lens 12, and the parallel light passes through the beam splitter 13, is reflected by the shape variable mirror 1, and is lasered by the quarter wavelength plate 14. After the polarization state of the light is changed, the light is condensed by the objective lens 15 and focused on the optical disk 20. The laser light reflected from the optical disk 20 passes through the objective lens 15 and the quarter-wave plate 14, is reflected by the shape variable mirror 1, and passes through the beam splitter 13 and is collected by the condenser lens 16. 17 is condensed.

  In such an optical pickup device 10, one of the deformable mirrors 1 serves as a conventional rising mirror. On the other hand, an optical distortion (coma aberration, spherical aberration, etc.) generated in the laser light emitted from the semiconductor laser 11 by appropriately deforming the mirror surface 3a according to a command from the deformable mirror control unit 18. It also plays a role in correcting aberrations.

  For example, the deformable mirror control unit 18 is configured to control the operation of the deformable mirror so as to appropriately deform the mirror surface 3a of the deformable mirror 1 based on information stored in advance in a memory (not shown). It is also good. Further, the configuration of controlling the operation of the deformable mirror 1 while appropriately changing the voltage applied to the piezoelectric actuator 5 so as to obtain a preferable mirror surface 3a state based on the signal obtained by the photodetector 17 may be adopted. I do not care.

  In the optical pickup device 10 of the present embodiment, the deformable mirror 1 is configured to have a function as a rising mirror, but the present invention is not necessarily limited to this, and other configurations may be used. I do not care.

  In the above description, the variable shape mirror 1 of the present invention is used for the optical pickup device 10. However, since the deformable mirror of the present invention can correct optical distortion of an incident light beam, it can be widely applied to an optical device, and can be applied to, for example, a video projector and a digital camera.

  In the embodiment described above, the variable shape mirror 1 has a rectangular shape as shown in FIG. 1, but is not particularly limited to this shape and does not depart from the object of the present invention. Various changes can be made within the range. For example, the base 2 and the mirror substrate 3 may be configured in a circle, or the base 2 and the mirror substrate 3 may have different sizes.

  Since the deformable mirror according to the present invention can reduce the local distortion generated on the mirror surface, the optical distortion of the light beam can be appropriately corrected. In addition, since the operation efficiency of the piezoelectric actuator that deforms the mirror surface is good, it is possible to reduce power consumption. Therefore, the variable shape mirror of the present invention and the optical pickup device including the same are useful.

These are the schematic perspective views which show the structure of the variable shape mirror of this embodiment. These are sectional drawings in the AA position of FIG. These are explanatory drawings for demonstrating the modification of the variable shape mirror of this embodiment. These are the schematic diagrams which show the structure of the optical system of an optical pick-up apparatus provided with the shape variable mirror of this embodiment. These are schematic sectional drawing which shows the structure of the conventional variable shape mirror. These are explanatory drawings for demonstrating the problem of the conventional variable shape mirror.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shape variable mirror 2 Base 3 Mirror board | substrate 3a Mirror surface 4 Support | pillar 5 Piezoelectric actuator 8 Adjustment member 10 Optical pick-up apparatus

Claims (4)

Base and
A mirror substrate disposed opposite to the base and having a mirror surface formed on a surface opposite to the surface facing the base;
A support column disposed on the base and supporting the mirror substrate;
A piezoelectric actuator that has a piezoelectric body that expands and contracts by applying a voltage, is disposed on the base, and displaces a movable portion that is not joined to the support of the mirror substrate; and
In a variable shape mirror comprising:
An adjustment member for height adjustment made of a material different from that of the piezoelectric body is joined to an end portion of the piezoelectric actuator facing the mirror substrate.
The adjustment member is made of the same material as that of the end of the support that is joined to the mirror substrate,
The variable shape mirror, wherein the mirror substrate and the adjustment member are not joined.   The variable shape mirror according to claim 1, wherein the support column is formed of the same material from an end portion joined to the mirror substrate to an end portion joined to the base. A base, a mirror substrate disposed opposite to the base and having a mirror surface formed on a surface opposite to the surface facing the base, a column disposed on the base and supporting the mirror substrate, and a voltage applied A piezoelectric actuator that has a piezoelectric body that expands and contracts, and is disposed on the base and displaces a movable part that is not joined to the support column of the mirror substrate;
Bonding an adjustment member for height adjustment made of the same material as an end portion to be bonded to the mirror substrate of the support column to an end portion of the piezoelectric actuator facing the mirror substrate;
Polishing the piezoelectric actuator to which the support column and the adjustment member are bonded together in a state of being bonded to the base;
A method of manufacturing a deformable mirror, comprising:   An optical pickup device comprising the variable shape mirror according to claim 1.