JP2020124068A - Displacement magnification device with variable and zero thermal expansion and variable shape secondary mirror unit including the same - Google Patents

Abstract

To provide a displacement magnification device capable of achieving low thermal expansion even with an actuator member with a high coefficient of thermal expansion and a variable shape secondary mirror unit including the same.SOLUTION: A bottom of a thermal expansion actuator 1' is fixed to a bottom base 2, and an upper part of the thermal expansion actuator 1' is fixed to an upper base 3. A pair of base arms 4a', 4b' is connected to the bottom base 2 at a bottom thereof via plate springs 5a, 5b and connected to the upper base 3 at a middle thereof via plate springs 6a, 6b. Each of resilient blocks 7a', 7b' is fixed at a predetermined angle to an upper part of each of base arms 4a', 4b', and a displacement output block 9 is provided between the resilient blocks 7a', 7b'. An apparent thermal expansion coefficient at a displacement output point of the displacement magnification device can be designed variably by designing a high thermal expansion coefficient γof a displacement magnification mechanism (4a', 4b'; 7a', 7b') and a high thermal expansion coefficient γof the thermal expansion actuator 1'.SELECTED DRAWING: Figure 3A

Description

The present invention relates to a displacement magnifying device having variable thermal expansion and zero thermal expansion, and a variable shape secondary mirror unit using the same.

FIG. 11 is a schematic diagram showing a radio astronomy satellite having a deformable secondary mirror to which the present invention is applied.

In FIG. 11, the radio astronomy satellite is composed of a main body 101 having a power feeding unit 101a, a primary mirror 102, a variable shape secondary mirror unit 103 arranged at the focal point of the primary mirror 102, a solar cell panel 104, and the like. The radio wave is reflected once by the primary mirror 102, further reflected by the variable shape secondary mirror unit 103, and guided to the power feeding portion 101a of the main body 101. In this radio astronomy satellite, the variable shape secondary mirror unit 103 is used in order to reduce a phase error (path error) of a radio wave caused by deformation of the primary mirror 102 in orbit. If a deformable mirror is introduced into the main mirror 102, the harness of the shape adjusting actuator and the like are incorporated into the large deployable mirror, resulting in a decrease in reliability.

FIG. 12 is a diagram for explaining the operation of the primary mirror 102 and the variable shape secondary mirror unit 103 of FIG.

As shown in FIG. 12A, the radio wave R1 having no path error is reflected by the main mirror 102 and further by the variable shape secondary mirror unit 103, and is directed to the power feeding portion 101a of the main body 101. At this time, as shown in FIG. 12B, when the mirror surface temperature of the primary mirror 102 changes by, for example, −157° C. to 116° C. and the primary mirror 102 deforms, the primary mirror 102 passes through the variable shape secondary mirror unit 103. A path error occurs in the radio wave R2 toward the power feeding unit 101a of the main body 101. On the other hand, as shown in FIG. 12C, the path error in the radio wave R2 is measured by the propagation holography method in the power feeding unit 101a, the optical shape measuring method of the primary mirror 102, etc., and the variable shape secondary mirror unit 103 is used. The radio wave R2 is corrected by the correction, and as a result, the corrected radio wave R3 toward the deformable secondary mirror unit 103 has no path error.

The variable shape secondary mirror unit 103 of FIG. 11 is configured by a common base, a variable shape mirror, and a plurality of displacement magnifying devices provided between the common base and the variable shape mirror (see FIG. 8).

13A and 13B show a first conventional displacement magnifying apparatus having a piezoelectric actuator and a two-stage displacement magnifying mechanism. FIG. 13A is a plan view and FIG. 13B is a side view (see Patent Document 1).

In FIG. 13, the displacement magnifying apparatus is connected to the gate-shaped fixed base 201, the piezoelectric actuator 202 whose one end is connected to the bottom of the gate-shaped fixed base 201, and the leg of the gate-shaped fixed base 201 via the hinge 201a, A pair of L-shaped arms (first displacement magnifying mechanism) 203 connected to the other end of the piezoelectric actuator 202 via a first free end portion 201b, and a second free end portion of the L-shaped arm 203. It is configured by a strip-shaped buckling spring (second displacement magnifying mechanism) 204 connected between 201c and a displacement output unit 205 formed in the central portion of the buckling spring 204.

In the displacement enlarging device of FIG. 13, when the piezoelectric actuator 202 expands and contracts as shown by the arrow X1, the first free end portion 201b and the second free end portion 201c of the L-shaped arm 203 move around the hinge portion 201a. Based on the principle of "", it rotates as indicated by arrows X2 and X3. Therefore, the displacement output unit 205 fluctuates up and down as shown by the arrow X4. As a result, the displacement [Delta] L ₂ of the height _{L 2} of the displacement output portion 205 relative displacement [Delta] L ₁ length _{L 1} of the piezoelectric actuator 202 is expanded.

In the displacement enlarging device of FIG. 13, the enlarging displacement amount N due to thermal expansion can be expressed by the following equation.
N=K ₁ ·(α ₁ −α ₂ )+K ₂ ·(α ₃ −α ₂ ).
However, K ₁ is the expanded displacement amount due to the thermal expansion of the first displacement magnifying mechanism (L-shaped arm 203) K ₂ is the expanded displacement amount α ₁ due to the thermal expansion of the second displacement magnifying mechanism (buckling spring 204) The coefficient of thermal expansion α ₂ of the piezoelectric actuator 202 is the coefficient of thermal expansion of the first displacement magnifying mechanism (L-shaped arm 203) α ₃ is the coefficient of thermal expansion of the second displacement magnifying mechanism (buckling spring 204) where | Each member is selected so that K ₁ ·(α ₁ −α ₂ )+K ₂ ·(α ₃ −α ₂ )|≦20 ppm/K holds. For example, the coefficient of thermal expansion α ₁ =−4.4 ppm/K of the ceramic of the piezoelectric actuator 202, the coefficient of thermal expansion α ₂ =13 ppm/K of the tool steel (SKD) of the L-shaped arm 203, and the phosphorus of the buckling spring 204. When the coefficient of thermal expansion of bronze α ₃ =18 ppm/K,
Raise the temperature from room temperature to 80℃ and N=+10μm
Becomes

As described above, according to the first conventional displacement magnifying apparatus shown in FIG. 13, low thermal expansion can be realized by selecting the respective materials so that the expansion of the two stages of thermal deformation cancels each other.

However, in the first conventional displacement magnifying apparatus shown in FIG. 13, the piezoelectric actuator 202 has the advantages of good responsiveness and low power consumption, but the piezoelectric actuator 202 has a large number of parts, resulting in high reliability. Inferior. Further, the thermal expansion coefficient α ₁ of the piezoelectric actuator 202 must be reduced, and the thermal expansion coefficients α ₂ and α _{3 of} the first and second displacement magnifying mechanisms must also be reduced. Therefore, it is not suitable for a displacement magnifying device using a member having a high thermal expansion coefficient.

The second conventional displacement magnifying device has a thermal expansion actuator and a one-stage displacement magnifying mechanism (see Non-Patent Document 1). In this case, the thermal expansion actuator is composed of, for example, an aluminum alloy (A5052) having a high coefficient of thermal expansion and a silicone rubber heater provided on the outer periphery of the aluminum alloy. Therefore, the thermal expansion actuator has a small number of parts, resulting in high reliability.

JP-B-1-50193 (JP-A-60-288782)

Reo Kashiyama et. al., “Athermalization of deformable reflector's actuators for radio astronomy satellites”, 2018 AIAA Spacecraft Structures Conference, AIAA SciTech Forum, 8-12 January 2018, Kissimmee, Florida, USA. Kai Wang et. al., “The perfect crystal, thermal vacancies and the thermal expansion coefficient of aluminium”, Philosophical Magazine A, 2000, VOL. 80, No. 7, 1629-1643. Akira Ohnishi et. al., “Flight performance of HALCA satellite thermal control”, SAE Technical paper series, 28th International Conference on Environmental Systems, 13-16 July 1998, Danvers, Massachusetts, USA.,

In the above second conventional displacement magnifying device, the thermal expansion actuator is made of an aluminum alloy (A5052) having a high thermal expansion coefficient, for example, 23.8 ppm/K, and the one-stage displacement magnifying mechanism has a low thermal expansion coefficient, for example, 0.02 ppm/K. K invar (IC-LTX). Therefore, the displacement of the thermal expansion of the member having a high coefficient of thermal expansion is expanded by the displacement magnifying mechanism having a low coefficient of thermal expansion due to the temperature change of the surrounding environment, and the low thermal expansion cannot be realized. There is a problem called.

In order to solve the above-mentioned problems, a displacement magnifying apparatus according to the present invention is capable of expanding and contracting an actuator, a bottom base fixed to the bottom part of the actuator, an upper base fixed to the upper part of the actuator, and a bottom base. A displacement magnifying device having a displacement magnifying power K, which includes a displacement magnifying mechanism which is provided above and an intermediate portion of which is suspended from an upper base, and a displacement output block which is provided on the displacement magnifying mechanism and is located on the upper base. Then, when the apparent thermal expansion coefficient A [ppm/K] is required, A can be variably designed by designing γ ₁ and γ ₂ from the following equations.
A=K·(L ₁ /L ₂ )·γ ₁ −(K·(L ₁ /L ₂ )−1)·γ ₂

The variable shape secondary mirror unit according to the present invention includes a common base, a variable shape mirror, and the above-described displacement magnifying device provided between the common base and the variable shape mirror.

According to the present invention, even with an actuator member having a high coefficient of thermal expansion, low thermal expansion can be realized by using a member having a larger coefficient of high thermal expansion as the displacement magnifying mechanism.

It is a side view which shows the displacement magnifying apparatus as a 1st comparative example. It is a side view which shows the displacement magnifying apparatus as a 2nd comparative example. It is a side view showing an embodiment of a displacement enlarging device according to the present invention. It is a figure explaining the integral molding of the member of FIG. 3A. It is a figure for demonstrating the drive operation of the displacement magnification apparatus of FIG. 3A. It is a figure for demonstrating the thermal expansion operation of the displacement expansion apparatus of FIG. 3A. 3B is a graph for determining a coefficient of thermal expansion of a member of the displacement magnifying device of FIG. 3A. It is a figure of an experimental result which shows the thermal expansion characteristic at the time of heating of the displacement magnification device of Drawing 6A. It is a side view which shows the example of a change of the displacement magnification apparatus of FIG. 3A. FIG. 8 is a perspective view showing a variable shape secondary mirror unit using the displacement magnifying device of FIGS. 1 and 7. FIG. 9 is an enlarged view of the deformable mirror of FIG. 8, (A) being a top view and (B) being a back view. FIG. 9 is a diagram for explaining the operation of the variable shape secondary mirror unit of FIG. 8. It is a perspective view showing a radio astronomy satellite having a variable shape secondary mirror to which the present invention is applied. It is a figure for demonstrating operation|movement of the primary mirror of FIG. 11, and a secondary mirror. The 1st conventional displacement magnifying device is shown, (A) is a top view, (B) is a side view.

Before describing the embodiments of the present invention, a displacement magnifying device as a comparative example will be described.

FIG. 1 is a side view showing a displacement magnifying apparatus as a first comparative example.

In FIG. 1, the expandable piezoelectric actuator 1 is housed in a case 1a made of stainless steel (coefficient of thermal expansion 17.3 ppm/K) and has a low coefficient of thermal expansion α ₁ =-1.18 ppm/K. The bottom of the piezoelectric actuator 1 is fixed to the bottom base 2, and the upper base 3 is fixed to the top of the piezoelectric actuator 1. The pair of base arms 4a, 4b are connected at their bottoms to the bottom base 2 via leaf springs 5a, 5b, and in the middle thereof to the upper base 3 via leaf springs 6a, 6b. Elastic blocks 7a and 7b are fixed to the upper portions of the base arms 4a and 4b at a predetermined angle, and a displacement output block 8 is provided between the elastic blocks 7a and 7b. Since the base arms 4a and 4b and the elastic blocks 7a and 7b are integrally molded, they constitute a one-stage displacement magnifying mechanism. Thus, the displacement [Delta] L ₁ is displacement enlarging mechanism in the length _{L 1} the piezoelectric actuator 1 (4a, 4b; 7a, 7b) of the enlargement to the displacement [Delta] L ₂ length _{L 2.}

In FIG. 1, the piezoelectric actuator 1 housed in the case 1a has a low coefficient of thermal expansion of −1.18 ppm/K, and in this case, the displacement magnifying mechanism (4a, 4b; 7a, 7b) has a coefficient of thermal expansion of almost 0. If it is configured with Invar (IC-ITX), a displacement enlarging device with low thermal expansion can be realized by using a member with a low thermal expansion coefficient. However, since the case 1a is required, the structure becomes complicated. Further, the disc spring 1b deviates from the case 1 due to the temperature change due to the difference in thermal expansion coefficient between the case 1a (17.3 ppm/K) and the piezoelectric actuator 1 (-1.18).

FIG. 2 is a side view showing a displacement magnifying apparatus as a second comparative example.

In FIG. 2, instead of the case 1a (stainless steel) of FIG. 1, a case 1b having a zero coefficient of thermal expansion (0.02 ppm/K invar (IC-LTX)) is provided, and the difference in the residual coefficient of thermal expansion is provided. In order to cancel the above, a thermal expansion adjusting member 10 (coefficient of thermal expansion 13.6 ppm/K) is inserted between the piezoelectric actuator 1 and the bottom base 2. As a result, a displacement expanding device with low thermal expansion using an actuator with low thermal expansion coefficient is realized. In this case, the thermal expansion coefficient alpha ₁ of the piezoelectric actuator _{1, 'hand,} the length L ₁ of the length L ₁ and the thermal expansion adjustment member 10 of the piezoelectric actuator _1' thermal expansion coefficient alpha ₁ of the thermal expansion adjustment member 10,
α ₁ '/α ₁ =-L ₁ /L ₁ '
Designed to meet. As a result, if α ₁ =−1.18 ppm/K and α ₁ ′=13.6 ppm/K, L ₁ =104 mm and L ₁ ′=9.02 mm, but due to the thermal expansion adjusting member 10. The structure is complicated, and the thermal expansion adjusting member 10 is increased in size. In the second comparative example, when a thermal expansion actuator made of an aluminum alloy having a high coefficient of thermal expansion is used instead of the piezoelectric actuator 1, α ₁ =23.8 ppm/K and L ₁ =104 mm, for example, α ₁ If'=-4 ppm/K, L ₁ '=619 mm, which is very large. Therefore, it is impossible to realize a small displacement enlarging device having a low thermal expansion using a member having a high thermal expansion coefficient.

FIG. 3A is a side view showing an embodiment of the displacement magnifying apparatus according to the present invention.

In FIG. 3A, a thermal expansion actuator 1′ having a high thermal expansion coefficient γ _{1 around} which a silicone rubber heater 1′a is wound is provided instead of the piezoelectric actuator 1 having the low thermal expansion coefficient α ₁ shown in FIG. The thermal expansion actuator 1'is made of, for example, an aluminum alloy having γ ₁ =23.8 ppm/K. The low thermal expansion coefficient alpha ₂ of 2 'displacement enlargement mechanism (4a, 4b; 7a, 7b ) high thermal expansion coefficient gamma ₂ displacement enlarging mechanism in place of the (base arm 4a', 4b '; resilient block 7a' , 7b' are provided, and the base arms 4a', 4b' and the elastic blocks 7a', 7b' are made of integrally molded magnesium alloy (AZ-31), for example, γ ₂ =27.3 ppm/K. The two high thermal expansion coefficients γ ₁ and γ ₂ are
γ ₁ <γ ₂
To be satisfied.

As shown in FIG. 3B, the members in FIG. 3A are members 2, 3 including the displacement magnifying mechanism (4a′, 4b′; 7a′, 7b′) excluding the thermal expansion actuator 1′ and the heater 1′a. 4a', 4b', 5a, 5b, 6a, 6b, 7a', 7b' and 8 are integrally molded with, for example, a magnesium alloy. This facilitates assembly. In this case, the members 5a, 5b, 6a, 6b, 7a', 7b' are thin and act as leaf springs or elastic members.

In FIG. 3A, when the thermal expansion actuator 1'expands and contracts as shown by the arrow Y1, the displacement magnifying mechanism (base arms 4a', 4b' and elastic blocks 7a', 7b') has a lever lever 5a, 5b. According to the principle of "", it rotates like the arrow Y2. As a result, the displacement ΔL ₁ of the thermal expansion actuator 1′ is magnified by the displacement magnifying mechanism (4a′, 4b′; 7a′, 7b′) to become the displacement ΔL ₂ of the displacement output block 8. This will be described in detail with reference to FIGS. 4 and 5.

As shown in FIG. 4A, the thermal expansion actuator 1′ having a length L ₁ expands and contracts with a displacement ΔL ₁ . As a result, as shown in FIG. 4B, the length L _{2 of} the displacement magnifying mechanism (4a′, 4b′; 7a′, 7b′), that is, the length (distance) between the displacement output block 8 and the bottom base 2. L ₂ expands and contracts with displacement ΔL ₂ . Here, when the displacement magnifying power K is introduced, as shown in FIG.
ΔL ₂ =K·ΔL ₁ (1)
It can be expressed as.

Next, the thermal expansion operation of the displacement magnifying apparatus of FIG. 3A will be described with reference to FIG.

As shown in FIG. 5A, the thermal expansion actuator 1′ having the length L ₁ expands and contracts by ΔL _{1 with} respect to the temperature change ΔT.
ΔL ₁ =γ ₁ ·L ₁ ·ΔT (2)
However, γ ₁ is a thermal expansion coefficient of the thermal expansion actuator 1′.

As shown in FIG. 5B, the displacement magnifying mechanism (4a, 4b; 7a, 7b) having the length L ₂ expands or contracts by ΔL ₂ ′ with respect to the temperature change ΔT.
ΔL ₂ '=γ ₂ ·L ₁ ·ΔT (3)
However, γ ₂ is the thermal expansion coefficient of the displacement magnifying mechanism (4a′, 4b′; 7a′, 7b′). At this time, if γ ₁ =0, the thermal expansion actuator 1′ has a negative thermal expansion coefficient (−γ ₂ ) with respect to the displacement output block 8 and the displacement magnifying mechanism (4a, 4b; 7a, 7b). It can be said that it expands and contracts by ΔL ₁ '.
ΔL ₁ '=-γ ₂ ·L ₁ ·ΔT (4)

Therefore, as shown in (C) of FIG. 5, the expansion/contraction amount ΔL ₁ of the thermal expansion actuator 1′ is calculated from the equations (2) and (4).
ΔL ₁ ← ΔL ₁ + ΔL ₁ '
=γ ₁ ·L ₁ ·ΔT-γ ₂ ·L ₁ ·ΔT (5)
Therefore, according to equations (1) and (3), the expansion/contraction amount ΔL ₂ in the displacement output block 8 of the displacement enlarging device is
ΔL ₂ ←ΔL ₂ +ΔL ₂ '
=K·ΔL ₁ +γ ₂ ·L ₂ ·ΔT (6)
Becomes Therefore, from equations (5) and (6),
ΔL ₂ ={K·L ₁ ·γ ₁ −(K·L ₁ −L ₂ )·γ ₂ }·ΔT (7)
Becomes Here, when the apparent thermal expansion coefficient A in the displacement output block 8 of the displacement enlarging device is introduced,
ΔL ₂ =A·L ₂ ·ΔT (8)
Becomes

From equations (7) and (8),
A=K·(L ₁ /L ₂ )·γ ₁ −(K·(L ₁ /L ₂ )−1)·γ ₂ (9)
Becomes Therefore, in order that the thermal expansion of the displacement magnifying mechanism (4a′, 4b′; 7a′, 7b′) becomes zero (A=0), the formula (10) needs to be established.
γ ₂ /γ ₁
=K·(L ₁ /L ₂ )/{K·(L ₁ /L ₂ )−1} (10)

In the equation (10), K·(L ₁ /L ₂ )>1 in general, so that, as described above,
γ ₂ >γ ₁
Is. By determining the thermal expansion coefficients γ ₁ and γ ₂ and the displacement expansion rate K so as to satisfy the expression (10) and setting the apparent thermal expansion coefficient A=0, a displacement expansion device with low thermal expansion can be realized. .. For example, if γ ₁ =23.8 ppm/K (A5052), L ₁ =130 mm, L ₂ =165 mm, and K=10, the equation (9) can be expressed as shown in FIG. 6A. As shown in FIG. 6A, when the thermal expansion actuator 1′ is an aluminum alloy (A5052) which is a high thermal expansion material, the thermal expansion coefficient γ ₁ is 23.8 ppm/K, and in this case, the high thermal expansion coefficient γ ₂ = By using a magnesium alloy (AZ-31) of 27.3 ppm/K, an apparent thermal expansion coefficient A=0 can be realized.

In the above example, there is a temperature dependence of the thermal expansion coefficient of the aluminum alloy (see: Figure 1 of p. 1632 of Non-Patent Document 2). On the other hand, in the case of radio astronomy satellites such as HALCA, the ambient temperature of the displacement magnifying device in orbit is about ±10° C. at most (see Non-Patent Document 3). Therefore, for an aluminum alloy of 23 to 25 ppm/K, according to Non-Patent Document 2 described above, only about 0.1 ppm/K (about 0.5%) changes, so that the thermal expansion coefficient of the aluminum alloy The temperature dependence can be ignored. It is also considered that the temperature dependence of the thermal expansion coefficient of the magnesium alloy is similar to the temperature dependence of the thermal expansion coefficient of the aluminum alloy.

FIG. 6B is a diagram of experimental results showing the thermal expansion characteristics of the displacement magnifying apparatus of FIG. 6A during heating. That is, heat generated by heating the displacement magnifying device (γ ₁ =23.8 ppm/K, γ ₂ =27.3 ppm/K, L ₁ =130 mm, L ₂ =165 mm) of γ ₁ <γ ₂ obtained in FIG. 6A. The expansion characteristic was ΔL ₂ =0.04 mm, and zero expansion was realized by the variable thermal expansion design of the present invention. On the other hand, the thermal expansion characteristics of the displacement magnifying device of γ ₁ >γ ₂ (γ ₁ =23.8 ppm/K, γ ₂ =0.02 ppm/K, L ₁ =130 mm, L ₂ =165 mm) are ΔL. It was a large thermal expansion of ₂ = 1.98 mm. In addition, the difference between the experimental result and the theoretical formula of equation (9) was within the measurement error range for both the displacement magnifying device of γ ₁ <γ _{2 and} the displacement magnifying device of γ ₁ >γ ₂ , and the validity of the theory was confirmed. ..

From the experimental results and theory, the present invention is not limited to zero expansion, and for example, the apparent thermal expansion coefficient in the displacement output block of the displacement magnifying device can be designed to be variable.

The present invention is not limited to the displacement magnifying device shown in FIG. 3, and various modifications such as a displacement magnifying device having different displacement magnifying ratios are possible. For example, as shown in FIG. 7, blocks 7a"-1, 7b"-1 and leaf springs 7a"-2, 7b"-2 are provided instead of the elastic blocks 7a', 7b' of FIG. In this case, the blocks 7a″-1, 7b″-1 and the base arms 4a′, 4b′ are the same member, for example, a magnesium alloy (AZ-31) having a thermal expansion coefficient of 27.3 ppm/K, and are screwed at a predetermined angle. It is fixed. Further, the piezoelectric actuator 1 may be used instead of the thermal expansion actuator 1 ′, as long as it satisfies the above formula (10).

FIG. 8 is a perspective view showing a variable shape secondary mirror unit using the displacement magnifying device of FIGS. 1 and 7.

In FIG. 8, the variable shape secondary mirror unit includes a common base 11, a hyperbolic shape variable mirror 12 made of an aluminum alloy, and six displacement variable devices provided between the common base 11 and the variable shape mirror 12. 13-1, 13-2,..., 13-6. The displacement varying devices 13-1, 13-2,..., 13-6 are those shown in FIGS. In FIG. 8, it is preferable to provide a light-shielding seal 14 (see FIG. 10) on the outer peripheral side of the displacement varying devices 13-1, 13-2,..., 13-6, and to displace the displacement varying devices 13-1, 13-2. , 13-6 prevent thermal disturbance to the high thermal expansion coefficient actuators 1 and 1′ and the base arms 4a and 4b; 4a′ and 4b′.

9A and 9B are enlarged views of the deformable mirror 12 of FIG. 8, in which FIG. 9A is a top view and FIG. 9B is a back view.

As shown in FIG. 9, the deformable mirror 12 is provided with radial slits 12a in order to reduce anisotropy in bending rigidity.

FIG. 10 is a diagram for explaining the operation of the variable shape secondary mirror unit of FIG.

As shown in FIG. 10A, the variable shape mirror 12 is in contact with the displacement output block 8 of the displacement variable device 13-1 (13-2,..., 13-6) due to its rigidity. In this state, when the actuator 1 (1') of the displacement varying device 13-1 (13-2,..., 13-6) is displaced, the displacement output block 8 is displaced, and the arrow in (B) of FIG. As shown, the deformable mirror 12 is displaced.

In the above-described embodiment, as the displacement magnifying mechanism, a pair of base arms 4a, 4b, leaf springs 5a, 5b, leaf springs 6a, 6b, blocks 7a (7a'), 7b (7b'), leaf plates. One pair of springs 7a″ and 7b″ is provided, but the symmetry is lost, but only one may be provided.

Further, the present invention can be applied to any modification within the obvious range of the above-described embodiment.

INDUSTRIAL APPLICABILITY The displacement magnifying device according to the present invention can be used for an actuator of a tracking correction magnetic head, etc., in addition to a variable shape secondary mirror.

1: Piezoelectric actuator 1': Thermal expansion actuator 1'a: Heater 2: Bottom base 3: Top bases 4a, 4b, 4a', 4b': Base arm
5a, 5b: leaf springs 6a, 6b: leaf springs 7a, 7b: elastic blocks 7a', 7b': blocks 7a", 7b": leaf spring 8: displacement output block 11: common base 12: deformable mirror
12a: Slits 13-1, 13-2,..., 13-6: Displacement variable device 14: Light-shielding seal 101: Main body 101a: Power supply part 102: Main mirror 103: Variable shape secondary mirror 104: Solar cell panel 201: Gate Shaped solid base portion 201a: Hinge portion 201b: First free end portion 201c: Second free end portion 202: Piezoelectric actuator 203: L-shaped arm 204: Buckling spring

Claims (11)

An extendable actuator,
A bottom base fixed to the bottom of the actuator,
An upper base fixed to the upper part of the actuator,
A displacement magnifying mechanism in which a bottom portion is provided on the bottom portion base, and an intermediate portion is suspended from the upper portion base;
A displacement output block provided on the displacement magnifying mechanism and located on the upper base;
When the apparent thermal expansion coefficient A [ppm/K] is required for the displacement enlarging device with the displacement enlarging factor K, A can be variably designed by designing γ ₁ and γ ₂ from the following equations. Displacement magnifying device.
A=K·(L ₁ /L ₂ )·γ ₁ −(K·(L ₁ /L ₂ )−1)·γ ₂ Let L ₁ , ΔL ₁ and γ ₁ be the length, displacement and coefficient of thermal expansion of the actuator,
When the length, displacement and thermal expansion coefficient of the displacement magnifying mechanism are L ₂ , ΔL ₂ and γ ₂ ,
γ ₂ /γ ₁
=K·(L ₁ /L ₂ )/{K(L ₁ /L ₂ )−1}
However, K is the displacement magnifying apparatus according to claim ₁ , wherein the displacement magnifying rate ΔL ₂ /ΔL ₁ . The displacement magnifying mechanism,
A base arm having a bottom portion provided on the bottom portion base via a first spring member, and an intermediate portion connected to the upper portion base via a second spring member;
The displacement magnifying apparatus according to claim 1, further comprising: a resilient block integrally molded with the base arm, inclined toward the actuator at a predetermined angle with respect to the base arm, and provided with the displacement output block at a tip thereof. .. The displacement magnifying apparatus according to claim 3, wherein the bottom base, the upper base, the base arm, the elastic block, and the displacement output block are integrally molded. The displacement magnifying mechanism,
A base arm having a bottom portion provided on the bottom portion base via a first spring member, and an intermediate portion connected to the upper portion base via a second spring member;
A block fixed to the actuator side at a predetermined angle with respect to the base arm,
The displacement magnifying device according to claim 1, further comprising a second spring member provided between the tip of the block and the displacement output block. The displacement enlarging device according to claim 5, wherein the coefficient of thermal expansion of the block is the same as the coefficient of thermal expansion of the base arm. The displacement magnifying apparatus according to claim 1, wherein the actuator is a thermal expansion actuator. The displacement magnifying apparatus according to claim 1, wherein the actuator is a piezoelectric actuator. The displacement magnifying device according to claim 1, wherein the actuator is made of an aluminum alloy, and the displacement magnifying mechanism is made of a magnesium alloy. An extendable actuator,
A bottom base fixed to the bottom of the actuator,
An upper base fixed to the upper part of the actuator,
A displacement magnifying mechanism in which a bottom portion is provided on the bottom portion base, and an intermediate portion is suspended from the upper portion base;
A displacement output block provided on the displacement magnifying mechanism and located on the upper base;
A displacement enlarging device in which a thermal expansion coefficient of the displacement enlarging mechanism is larger than a thermal expansion coefficient of the actuator. Common base,
Deformable mirror and
A variable shape secondary mirror unit comprising: the displacement magnifying device according to any one of claims 1 to 10, which is provided between the common base and the variable shape mirror.

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