JP6225537B2 - Variable shape element and head-up display for automobile - Google Patents

Description

  The present invention relates to a variable shape element and an automotive head-up display.

  A conventional variable shape element includes an electrolyte layer, a first electrode layer disposed on one side of the electrolyte layer, and a second electrode layer disposed on the opposite side of the electrolyte layer to one side. (See, for example, Patent Document 1).

  In this structure, the first and second electrode layers and the electrolyte layer constitute an ion conductive polymer actuator (hereinafter simply referred to as an actuator). When a voltage is applied between the first and second electrode layers from the power source, ions move in the electrolyte layer along the electric field between the first and second electrode layers, and the electrolyte layer is bent. As a result, the first and second electrode layers are deformed along the electrolyte layer. Therefore, the actuator can be deformed into an arbitrary shape by changing the voltage applied between the first and second electrode layers from the power source.

Japanese Patent No. 4646530

  The present inventor configures a charging circuit in which a switch and an actuator are connected in series between a positive electrode and a negative electrode of a power source based on the above-mentioned Patent Document 1, and controls the on / off of the switch by a control circuit, whereby the actuator We studied the control of the shape.

  In order to deform the actuator into an arbitrary shape, it is necessary to charge the actuator from the power source until the target voltage corresponding to the arbitrary shape is reached between the first and second electrode layers. However, the time constant of the charging circuit is large. Especially at low temperatures, the internal resistance of the actuator increases. For this reason, at a low temperature, the time constant of the charging circuit is further increased.

  Therefore, it takes a long time from when the switch is turned on by the control circuit to start charging the actuator from the power source until the voltage between the first and second electrode layers reaches the target voltage. That is, it takes a long time from when the switch is turned on by the control circuit until the voltage between the first and second electrode layers reaches the target voltage and the switch is turned off. Accordingly, the control circuit continues to execute the charging process for charging the actuator via the switch for a long time.

  In view of the above points, the present invention provides a variable shape element that makes it possible to shorten the time required for the control circuit to perform the charging process on the actuator, and an automotive head-up display using the variable shape element. Objective.

  In order to achieve the above object, in the invention according to claim 1, an electrolyte membrane (30) made of an ion exchange resin, a first electrode layer (31) formed along one side of the electrolyte membrane, A second electrode layer (32 to 35) formed along the opposite surface of the electrolyte membrane that is located on the opposite side of the one surface, and the second power source (50a to 50d) that can variably control the voltage. When a voltage is applied between the first and second electrode layers, ions move in the electrolyte membrane due to the electric field between the first and second electrode layers, and the electrolyte membrane becomes the first and second electrodes. Actuators (40a to 40d) bent together with the layers, and capacitors (52a to 52d) connected in parallel to the actuator between the positive electrode and the negative electrode of the power source and having a capacitance larger than the capacitance of the actuator 52d) and a After the switches (51a to 51d) connected between the common connection terminals (41a to 41d) between the tutor and the capacitor and the power source are turned on and charging of the actuator and the capacitor from the power source is started. And a control circuit (54) for executing a charging process for turning off the switch before the charging of the actuator is completed. The time constant of the first charging circuit including the power source, the switch, and the capacitor is the power source, the switch And a time constant of the second charging circuit constituted by the actuator is smaller.

  According to the first aspect of the present invention, the time constant of the first charging circuit is smaller than the time constant of the second charging circuit. The capacitor has a capacitance larger than that of the actuator. Therefore, when the control circuit turns off the switch after the switch is turned on but before the charging of the actuator is completed, the electric charge necessary for completing the charging of the actuator can be stored in the capacitor and the actuator. Therefore, it is possible to shorten the time required from when the control circuit turns on the switch until the switch is turned off. As a result, the time required for the control circuit to execute the charging process for the actuator can be shortened.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a figure which shows the head-up display in one Embodiment of this invention. It is a front view of the optical mirror in the said embodiment. It is a rear view of the optical mirror in the said embodiment. It is IV-IV sectional drawing in FIG. It is a flowchart which shows the manufacturing process of the optical mirror of the said embodiment. It is a figure which shows the electrical constitution of the head-up display of the said embodiment. It is a perspective view which shows the electrolyte membrane which comprises the optical mirror in the said embodiment. It is a figure which shows the action | operation of the optical mirror in the said embodiment. It is a flowchart which shows the charge process of the control circuit of the optical mirror in the said embodiment. It is a figure which shows the electrical constitution of the head-up display in the modification of the said embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows the configuration of a first embodiment of an automotive head-up display 1 to which the variable shape element of the present invention is applied.

  As shown in FIG. 1, the head-up display 1 includes a display device 10 and an optical mirror 20. The display device 10 outputs display light in a planar shape. The optical mirror 20 reflects the planar display light output from the display device 10 toward the front windshield 21. The shape of the optical mirror 20 is changed to change the focal length and the reflection direction. Furthermore, the distortion and blur of the virtual image can be corrected according to the shape of the front windshield 21.

  Next, the structure of the optical mirror 20 of this embodiment will be described.

  As shown in FIGS. 2, 3, and 4, the optical mirror 20 is a variable shape element including an electrolyte layer 30 and electrode layers 31, 32, 33, 34, and 35. The electrolyte layer 30 is formed in a thin film shape, and the thin film ion exchange resin is impregnated with an ionic liquid (electrolytic solution). The electrolyte layer 30 is formed so that its thickness dimension is uniform in the surface direction. The electrolyte layer 30 is formed in a quadrangle when viewed from the thickness direction. As the ion exchange resin of the present embodiment, for example, a cation exchange resin such as Nafion (manufactured by DuPont), Flemion (manufactured by Asahi Glass Co., Ltd.), Aciplex (manufactured by Asahi Kasei Co., Ltd.) or the like is used.

  The electrode layer 31 is a first electrode that is formed in a thin film shape along the one side of the electrolyte layer 30 over the entire one side. The electrode layer 31 is made of a conductive metal film such as aluminum, silver, or gold. One surface side of the electrode layer 31 constitutes a light reflecting surface 31a in which the center point in the surface direction is the optical axis center, that is, the apex. The light reflecting surface 31a of the present embodiment is formed by polishing one side of the metal film constituting the electrode layer 31. As shown in FIGS. 2 and 3, the electrode layers 32, 33, 34, and 35 are respectively along the opposite surface 30b (see FIG. 4) side of the electrolyte layer 30 that is located on the opposite side to the one surface 30a side. It is formed as a thin film.

  The electrode layers 32, 33, 34, and 35 are each made of a conductive metal film that is formed along the opposite surface 30 b of the electrolyte layer 30. The electrode layers 32, 33, 34, and 35 are dispersedly arranged on the opposite surface 30 b side of the electrolyte layer 30.

  Specifically, the electrode layer 32 is disposed on the upper right side in FIG. 3 of the opposite surface 30b. The electrode layer 32, together with the electrode layer 31 and the electrolyte layer 30, constitutes an ion conductive polymer actuator (hereinafter simply referred to as an actuator) 40a that deforms the light reflecting surface 31a as described later.

  The electrode layer 33 is disposed on the lower right side in FIG. 3 of the opposite surface 30b. The electrode layer 33, together with the electrode layer 31 and the electrolyte layer 30, constitutes an ion conductive polymer actuator (hereinafter simply referred to as an actuator) 40b that deforms the light reflecting surface 31a as described later.

  The electrode layer 34 is disposed on the lower left side in FIG. 3 of the opposite surface 30b. The electrode layer 34, together with the electrode layer 31 and the electrolyte layer 30, constitutes an ion conductive polymer actuator (hereinafter simply referred to as an actuator) 40c that deforms the light reflecting surface 31a as described later.

  The electrode layer 34 is disposed on the upper left side in FIG. 3 of the opposite surface 30b. The electrode layer 35, together with the electrode layer 31 and the electrolyte layer 30, constitutes an ion conductive polymer actuator (hereinafter simply referred to as an actuator) 40d that deforms the light reflecting surface 31a as described later.

  Hereinafter, in order to distinguish the electrode layer 31 from the electrode layers 32, 33, 34, and 35 for convenience of explanation, the electrode layer 31 is referred to as a single-sided electrode layer 31, and the electrode layers 32, 33, 34, and 35 are referred to as opposite surface electrodes. Layers 32, 33, 34, and 35 are used.

  Next, the manufacturing method of the optical mirror 20 of this embodiment is demonstrated with reference to FIG.

  First, in the first step, a cation exchange resin film made of a cation exchange resin is formed along one surface of the substrate (step S100). In the next second step, a conductive metal film is formed over the entire surface of the cation exchange resin film opposite to the substrate (step S110). In the next third step, the surface of the conductive metal film is polished to form the light reflecting surface 31a (step S120). Thereby, the single-sided electrode layer 31 having the light reflecting surface 31a is formed. In the next fourth step, the substrate is peeled off from the cation exchange resin film (step S130). In the fifth step, opposite electrode layers 32, 33, 34, and 35 made of a conductive metal film are formed on one surface of the cation exchange resin film from which the substrate has been peeled off (step S140). . Next, in the sixth step, the cation exchange resin membrane is impregnated with an ionic liquid (step S150). As a result, the electrolyte layer 30 is formed. Thus, the optical mirror 20 is completed.

  Next, the electrical configuration of the head-up display 1 of the present embodiment will be described with reference to FIG.

  As shown in FIG. 6, the head-up display 1 includes power supplies 50a, 50b, 50c, 50d, switches 51a, 51b, 51c, 51d, capacitors 52a, 52b, 52c, 52d, and resistive elements 53a, 53b, 53c, 53d. And a control circuit 54.

  The power supply 50a is a power supply device that can variably control its output voltage, and outputs voltage to the actuator 40a and the capacitor 52a. The switch 51a and the resistance element 53a are connected in series between the common connection terminal 41a between the actuator 40a and the capacitor 52a and the power supply 50a. The switch 51a is connected between the resistance element 53a and the common connection terminal 41a. The capacitor 52a is connected in parallel to the actuator 40a between the positive electrode and the negative electrode of the power supply 50a. The capacitance of the capacitor 52a is larger than the capacitance of the actuator 40a. The time constant of the first charging circuit composed of the power source 50a, the switch 51a, the resistance element 53a, and the capacitor 52a is that of the second charging circuit composed of the power source 50a, the switch 51a, the resistance element 53a, and the actuator 40a. It is smaller than the time constant.

  The power supply 50b is a power supply device capable of variably controlling the output voltage, and outputs a voltage to the actuator 40b and the capacitor 52b. The switch 51b and the resistance element 53b are connected in series between the common connection terminal 41b between the actuator 40b and the capacitor 52b and the power supply 50b. The switch 51b is connected between the resistance element 53b and the common connection terminal 41b. The capacitor 52b is connected in parallel to the actuator 40b between the positive electrode and the negative electrode of the power supply 50b. The capacitance of the capacitor 52b is larger than the capacitance of the actuator 40b. The time constant of the first charging circuit composed of the power supply 50b, the switch 51b, the resistance element 53b, and the capacitor 52b is the time constant of the second charging circuit composed of the power supply 50b, the switch 51b, the resistance element 53b, and the actuator 40b. It is smaller than the time constant.

  The power supply 50c is a power supply device capable of variably controlling the output voltage, and outputs a voltage to the actuator 40c and the capacitor 52c. The switch 51c and the resistance element 53c are connected in series between the common connection terminal 41c between the actuator 40c and the capacitor 52c and the power supply 50c. The switch 51c is connected between the resistance element 53c and the common connection terminal 41c. The capacitor 52c is connected in parallel to the actuator 40c between the positive electrode and the negative electrode of the power supply 50c. The capacitance of the capacitor 52c is larger than the capacitance of the actuator 40c. The time constant of the first charging circuit composed of the power supply 50c, the switch 51c, the resistance element 53c, and the capacitor 52c is that of the second charging circuit composed of the power supply 50c, the switch 51c, the resistance element 53c, and the actuator 40c. It is smaller than the time constant.

  The power supply 50d is a power supply device that can variably control its output voltage, and outputs voltage to the actuator 40d and the capacitor 52d. The switch 51d and the resistance element 53d are connected in series between the common connection terminal 41d between the actuator 40d and the capacitor 52d and the power supply 50d. The switch 51d is connected between the resistance element 53d and the common connection terminal 41d. The capacitor 52d is connected in parallel to the actuator 40d between the positive electrode and the negative electrode of the power supply 50d. The capacitance of the capacitor 52d is larger than the capacitance of the actuator 40d. The time constant of the first charging circuit composed of the power supply 50d, the switch 51d, the resistance element 53d, and the capacitor 52d is the time constant of the second charging circuit composed of the power supply 50d, the switch 51d, the resistance element 53d, and the actuator 40d. It is smaller than the time constant.

  In the present embodiment, organic transistors may be used as the switches 51a to 51d.

  The control circuit 54 includes a microcomputer, a memory, and the like, and controls the actuators 40a to 40d via the power supplies 50a to 50d and the switches 51a to 51d in order to change the shape of the light reflecting surface 31a. As will be described later, the actuators 40a to 40d are charged by corresponding power sources and capacitors and bend.

  Hereinafter, prior to the description of the charging process of the control circuit 54 of the present embodiment, the details of the operation of the actuators 40a to 40d will be described. This will be described with reference to FIGS. 7, 8A, and 8B. FIG. 7 is a rear view of the electrolyte layer 30. FIGS. 8A and 8B schematically show a connection configuration among the actuator 40a, the capacitor 52a, and the power source 50a, and the resistance element 53a is omitted.

  First, the power source 50a (or the capacitor 52a) applies a DC voltage between the electrode layers 31 and 32 constituting the actuator 40a. Then, the surface center 30c of the opposite surface 30b of the electrolyte layer 30 is fixed as a fixed end, and the corresponding electrolyte layer 301 (see FIG. 7) corresponding to the opposite electrode layer 32 of the electrolyte layer 30 and the single-sided electrode layer 31 A portion corresponding to the opposite electrode layer 32 (hereinafter referred to as an upper right electrode portion) and the opposite electrode layer 32 are bent.

  For example, the power source 50a (or the capacitor 52a) applies a DC voltage between the electrode layers 31 and 32 so that the single-sided electrode layer 31 is an anode electrode and the opposite-side electrode layer 32 is a cathode electrode. Then, the cation moves in the corresponding electrolyte layer 301 to the opposite electrode layer 32 side along the electric field between the electrode layers 31 and 32. Accordingly, as shown in FIG. 8A, the corresponding electrolyte layer 301 is bent so as to protrude toward the opposite electrode layer 32 side. Then, the upper right electrode part and the opposite electrode layer 32 are deformed so as to follow the corresponding electrolyte layer 301.

  The power source 50a (or capacitor 52a) applies a DC voltage between the electrode layers 31 and 32 so that the single-sided electrode layer 31 is a cathode electrode and the opposite-side electrode layer 32 is an anode electrode. Then, the cation moves in the corresponding electrolyte layer 301 toward the single-sided electrode layer 31 along the electric field between the electrode layers 31 and 32. Along with this, as shown in FIG. 8B, the corresponding electrolyte layer 301 is bent so as to be convex toward the single-sided electrode layer 31 side. Then, the upper right electrode part and the opposite electrode layer 32 are deformed so as to follow the corresponding electrolyte layer 301.

  Thus, when applying a direct current voltage between the electrode layers 31 and 32 from the power supply 50a (or the capacitor 52a) to bend the corresponding electrolyte layer 301, the applied voltage between the electrode layers 31 and 32 increases. The corresponding electrolyte layer 301 is greatly bent.

  Next, the power source 50b (or the capacitor 52b) applies a DC voltage between the single-sided electrode layer 31 and the opposite-side electrode layer 33 constituting the actuator 40b. Then, the surface direction center point 30c of the opposite surface 30b of the electrolyte layer 30 is fixed as a fixed end, and the corresponding electrolyte layer 302 (see FIG. 7) corresponding to the opposite electrode layer 33 in the electrolyte layer 30 and the single-sided electrode layer 31 Of these, the portion corresponding to the opposite electrode layer 33 (hereinafter referred to as the lower right electrode portion) and the opposite electrode layer 33 are bent.

  For example, the power source 50b (or the capacitor 52b) applies a DC voltage between the electrode layers 31 and 32 so that the single-sided electrode layer 31 is an anode electrode and the opposite-side electrode layer 33 is a cathode electrode. Then, the cation moves in the corresponding electrolyte layer 302 to the opposite electrode layer 33 side along the electric field between the electrode layers 31 and 33. Along with this, the corresponding electrolyte layer 302 is bent so as to protrude toward the opposite electrode layer 33 side. The lower right electrode portion and the opposite electrode layer 33 are deformed so as to follow the corresponding electrolyte layer 302.

  Further, the power source 50b (or the capacitor 52b) applies a DC voltage between the electrode layers 31 and 33 so that the single-sided electrode layer 31 is a cathode electrode and the opposite-side electrode layer 33 is an anode electrode. Then, the cation moves in the corresponding electrolyte layer 302 to the single-sided electrode layer 31 side along the electric field between the electrode layers 31 and 33. Along with this, the corresponding electrolyte layer 302 is bent so as to protrude toward the single-sided electrode layer 31. As a result, the lower right electrode portion and the opposite electrode layer 33 are deformed along the corresponding electrolyte layer 302.

  As described above, when the corresponding electrolyte layer 302 is bent by applying a DC voltage between the power source 50b (or the capacitor 52b) between the electrode layers 31 and 33, the applied voltage between the electrode layers 31 and 33 is increased. The corresponding electrolyte layer 302 bends greatly.

  Next, the power source 50c (or the capacitor 52c) applies a DC voltage between the single-sided electrode layer 31 and the opposite-side electrode layer 34 constituting the actuator 40c. Then, the surface center point 30c of the opposite surface 30b of the electrolyte layer 30 is fixed as a fixed end, and the corresponding electrolyte layer 303 (see FIG. 7) corresponding to the opposite electrode layer 34 of the electrolyte layer 30 and the single-sided electrode layer 31 Of these, the portion corresponding to the opposite electrode layer 34 (hereinafter referred to as the lower left electrode portion) and the opposite electrode layer 34 are bent.

  For example, the power source 50c (or the capacitor 52c) applies a DC voltage between the electrode layers 31 and 34 so that the single-sided electrode layer 31 is an anode electrode and the opposite-side electrode layer 34 is a cathode electrode. Then, cations move in the corresponding electrolyte layer 303 to the opposite electrode layer 34 side along the electric field between the electrode layers 31 and 34. Accordingly, the corresponding electrolyte layer 302 is bent so as to protrude toward the opposite electrode layer 34. Then, the lower left electrode portion and the opposite electrode layer 34 are deformed so as to follow the corresponding electrolyte layer 303.

  The power source 50c (or capacitor 52c) applies a DC voltage between the electrode layers 31 and 34 so that the single-sided electrode layer 31 is a cathode electrode and the opposite-side electrode layer 34 is an anode electrode. Then, cations move in the corresponding electrolyte layer 303 toward the single-sided electrode layer 31 along the electric field between the electrode layers 31 and 34. Along with this, the corresponding electrolyte layer 303 is bent so as to protrude toward the single-sided electrode layer 31. Then, the lower left electrode portion and the opposite electrode layer 34 are deformed so as to follow the corresponding electrolyte layer 303.

  As described above, when the direct current voltage is applied between the electrode layers 31 and 34 from the power source 50c (or the capacitor 52c) to bend the corresponding electrolyte layer 303, the applied voltage between the electrode layers 31 and 34 is increased. The corresponding electrolyte layer 303 bends greatly.

  Next, the power source 50d (or the capacitor 52d) applies a DC voltage between the single-sided electrode layer 31 and the opposite-side electrode layer 35 constituting the actuator 40d. Then, the surface direction center point 30c of the opposite surface 30b of the electrolyte layer 30 is fixed as a fixed end, and the corresponding electrolyte layer 304 (see FIG. 7) corresponding to the opposite surface electrode layer 35 of the electrolyte layer 30 and the single-sided electrode layer 31 Of these, the portion corresponding to the opposite electrode layer 35 (hereinafter referred to as the upper left electrode portion) and the opposite electrode layer 35 are bent.

  For example, the power source 50d (or capacitor 52d) applies a DC voltage between the electrode layers 31 and 35 so that the single-sided electrode layer 31 is an anode electrode and the opposite-side electrode layer 35 is a cathode electrode. Then, cations move in the corresponding electrolyte layer 304 to the opposite electrode layer 35 side along the electric field between the electrode layers 31 and 35. Accordingly, the corresponding electrolyte layer 304 is bent so as to protrude toward the opposite electrode layer 35. Then, the upper left electrode portion and the opposite electrode layer 35 are deformed along the corresponding electrolyte layer 304.

  The power source 50d (or capacitor 52d) applies a DC voltage between the electrode layers 31 and 35 so that the single-sided electrode layer 31 is a cathode electrode and the opposite-side electrode layer 35 is an anode electrode. Then, the cation moves in the corresponding electrolyte layer 304 to the single-sided electrode layer 31 side along the electric field between the electrode layers 31 and 35. Accordingly, the corresponding electrolyte layer 304 is bent so as to protrude toward the single-sided electrode layer 31. Then, the upper left electrode portion and the opposite electrode layer 35 are deformed along the corresponding electrolyte layer 304.

  As described above, when the direct current voltage is applied between the power source 50d (or the capacitor 52d) between the electrode layers 31 and 35 to bend the corresponding electrolyte layer 304, the applied voltage between the electrode layers 31 and 35 is increased. The corresponding electrolyte layer 304 bends greatly.

  Next, the charging process of the control circuit 54 of this embodiment is demonstrated using FIG. FIG. 9 is a flowchart showing the charging process of the control circuit 54. The control circuit 54 executes the charging process according to the flowchart of FIG.

  First, the control circuit 54 sequentially charges the actuators 40a, 40b, 40c, and 40d one by one (Step 100 to Step 130).

  Specifically, the control circuit 54 controls the output voltage of the power supply 50a, and turns on the switch 51a with the switches 51b, 51c, 51d turned off (step S100). Along with this, a current flows from the power source 50a to the capacitor 52a through the switch 51a and the resistance element 53a. A current flows from the power source 50a to the actuator 40a through the switch 51a and the resistance element 53a. That is, the capacitor 52a and the actuator 40a are charged by the output voltage of the power supply 50a. Thereafter, the control circuit 54 turns off the switch 51a. Accordingly, a current flows from the capacitor 52a to the actuator 40a. That is, the actuator 40a is charged from the capacitor 52a. Thereafter, the voltage between the electrode layers 31 and 32 of the actuator 40a reaches the target voltage. This completes the charging of the actuator 40a.

  Here, the target voltage of the actuator 40a is determined by the output voltage of the power source 50a and the ON period in which the switch 51a is turned on. For this reason, the target voltage increases as the output voltage of the power supply 50a increases, and the target voltage increases as the ON period of the switch 51a increases.

  Further, the control circuit 54 controls the output voltage of the power supply 50b when turning off the above-described switch 51a, and turns on the switch 51b with the switches 51c and 51d turned off (step S110). . Thus, the switch 51b is turned on and charging of the capacitor 52b and the actuator 40b from the power source 50b is started within a period in which the switch 51a is turned off and the capacitor 52a is charged into the actuator 40a.

  Accordingly, a current flows from the power supply 50b to the capacitor 52b through the switch 51b and the resistance element 53b. A current flows from the power supply 50b to the actuator 40b through the switch 51b and the resistance element 53b. That is, the capacitor 52b and the actuator 40b are charged by the output voltage of the power supply 50b. Thereafter, the control circuit 54 turns off the switch 51b. Accordingly, a current flows from the capacitor 52b to the actuator 40b. That is, the actuator 40b is charged from the capacitor 52b. Thereafter, the voltage between the electrode layers 31 and 33 of the actuator 40b reaches the target voltage. This completes charging of the actuator 40b.

  Here, the target voltage of the actuator 40b is determined by the output voltage of the power supply 50b and the ON period in which the switch 51b is turned on. For this reason, the target voltage increases as the output voltage of the power supply 50b increases, and the target voltage increases as the ON period of the switch 51b increases.

  Further, the control circuit 54 controls the output voltage of the power source 50c when turning off the above-described switch 51b, and turns on the switch 51c with the switches 51a and 51d turned off (step S120). . Thus, the switch 51c is turned on and charging of the capacitor 52c and the actuator 40c from the power source 50c is started within a period in which the switch 51b is turned off and the capacitor 52b is charged into the actuator 40b.

  Accordingly, a current flows from the power supply 50c to the capacitor 52c through the switch 51c and the resistance element 53c. A current flows from the power supply 50c to the actuator 40c through the switch 51c and the resistance element 53c. That is, the capacitor 52c and the actuator 40c are charged by the output voltage of the power supply 50c. Thereafter, the control circuit 54 turns off the switch 51c. Accordingly, a current flows from the capacitor 52c to the actuator 40c. That is, the actuator 40c is charged from the capacitor 52c. Thereafter, the voltage between the electrode layers 31 and 34 of the actuator 40c reaches the target voltage. This completes the charging of the actuator 40c.

  Here, the target voltage of the actuator 40c is determined by the output voltage of the power source 50c and the ON period in which the switch 51c is turned on. Therefore, the target voltage increases as the output voltage of the power supply 50c increases, and the target voltage increases as the ON period of the switch 51c increases.

  The control circuit 54 controls the output voltage of the power supply 50d when turning off the switch 51c described above, and turns on the switch 51d with the switches 51a and 51b turned off (step S120). . Thus, the switch 51d is turned on and charging of the capacitor 52d and the actuator 40d from the power source 50d is started within a period in which the switch 51c is turned off and the capacitor 52c is charged into the actuator 40c.

  Accordingly, a current flows from the power supply 50d to the capacitor 52d through the switch 51d and the resistance element 53d. A current flows from the power supply 50d to the actuator 40d through the switch 51d and the resistance element 53d. That is, the capacitor 52d and the actuator 40d are charged by the output voltage of the power supply 50d. Thereafter, the control circuit 54 turns off the switch 51d. Accordingly, a current flows from the capacitor 52d to the actuator 40d. That is, the actuator 40d is charged from the capacitor 52d. Thereafter, the voltage between the electrode layers 31 and 35 of the actuator 40d reaches the target voltage. This completes the charging of the actuator 40d.

  Here, the target voltage of the actuator 40d is determined by the output voltage of the power supply 50d and the ON period in which the switch 51d is turned on. For this reason, the target voltage increases as the output voltage of the power supply 50d increases, and the target voltage increases as the ON period of the switch 51d increases.

  As described above, the target voltages of the actuators 40a to 40d are controlled by controlling the output voltages of the power supplies 50a to 50d and the ON periods of the switches 51a to 51d, respectively. Thus, the degree to which the actuators 40a to 40d are bent can be controlled. Thereby, the electrode layer 31 and by extension, the light reflection surface 31a can be changed to a desired shape.

  According to the embodiment described above, the head-up display 1 includes the electrolyte membrane 30 made of an ion exchange resin, the single-sided electrode layer 31 formed along the single side 30a of the electrolyte membrane 30, and the electrolyte membrane 30. Of these, actuators 40a to 40d including electrode layers 32 to 35 on opposite surfaces formed along the opposite surface 30b located on the opposite side to the one surface 30a are provided. Capacitors 52a to 52d are connected in parallel to the actuators 40a to 40d between the positive electrodes and the negative electrodes of the power sources 50a to 50d, and are larger than the capacitance of the corresponding actuator among the actuators 40a to 40d It has electric capacity. The switches 51a to 51d are connected between the common connection terminals 41a to 41d between the actuators 40a to 40d and the capacitors 52a to 52d and the power sources 50a to 50d. The control circuit 54 turns on the switches 51a to 51d and starts charging the actuators 40a to 40d and the capacitors 52a to 52d from the power sources 50a to 50d, and then switches the switches 51a to 51d before the charging of the actuators 40a to 40d is completed. Execute the charging process to turn off.

  Here, for each actuator, the time constant of the first charging circuit is smaller than the time constant of the second charging circuit. Capacitors 52a to 52d have capacitances larger than the capacitances of the corresponding actuators among actuators 40a to 40d, respectively. For this reason, when the switches 51a to 51d are turned off before the charging of the actuator is completed after the switches 51a to 51d are turned on for each actuator, charges necessary for completing the charging of the actuator are stored in the capacitor and the actuator. be able to. Therefore, it is possible to shorten the time required for the control circuit 54 to turn on the switches 51a to 51d after the switches 51a to 51d are turned on. As a result, the time required for the control circuit 54 to execute the charging process for the actuators 40a to 40d can be shortened for each actuator.

  In the present embodiment, the switch 51b is turned on and charging of the capacitor 52b and the actuator 40b from the power supply 50b is started within a period in which the switch 51a is turned off and the capacitor 52a is charged into the actuator 40a. For this reason, the period which charges actuator 40a and the period which charges actuator 40b can overlap.

  Within the period in which the switch 51b is turned off and the actuator 52b is charged from the capacitor 52b, the switch 51c is turned on to start charging the capacitor 52c and the actuator 40c from the power source 50c. For this reason, the period which charges actuator 40b and the period which charges actuator 40c can overlap.

  Within the period in which the switch 51c is turned off and the actuator 52c is charged from the capacitor 52c, the switch 51d is turned on to start charging the capacitor 52d and the actuator 40d from the power source 50d. For this reason, the period which charges actuator 40c and the period which charges actuator 40d can overlap.

  As described above, the total time required to charge the actuators 40a, 40b, 40c, and 40d can be shortened.

  Further, in the head-up display 1 that does not use the capacitors 52a to 52d, when, for example, the switch 51a is turned off among the switches 51a to 51d, a leakage current flows between the electrode layers 31 and 32 of the actuator 40a. The actuator 40a bends according to the current. Alternatively, when the sneak current flows from the actuator adjacent to the actuator 40a to the actuator 40a when the switch 51a is off, the actuator 40a bends according to the sneak current.

  On the other hand, in the present embodiment, even when the switch 51a is turned off, the actuator 40a bends even if leakage current or sneak current occurs when a voltage is applied from the capacitor 52a to the actuator 40a. It is suppressed. Similarly, the actuators 40b, 40c, and 40d are also prevented from bending even if a leakage current or a sneak current occurs.

  In the variable shape element of Patent Document 1, the first and second electrode layers are formed independently for each actuator. For this reason, two wires for connecting the actuator and the power source are required for each actuator.

  On the other hand, in this embodiment, the single-sided electrode layer 31 is a common electrode layer for the actuators 40a to 40d. For this reason, the wiring which connects between the actuators 40a-40d and the power supplies 50a-50d can be reduced.

  In the present embodiment, the single-sided electrode layer 31 is a common electrode layer for the actuators 40a to 40d. For this reason, the man-hour of the manufacturing process which forms the single-sided electrode layer 31 in the single-sided 30a side of the electrolyte layer 30 can be reduced compared with the case where the single-sided electrode layer 31 provided for every actuator is provided.

  In the optical mirror 20 of the present embodiment, the light reflecting surface 31a is formed by polishing one side of the metal film constituting the electrode layer 31. Thereby, realization of the light reflection surface 31a with high reflectivity is attained. Therefore, it is possible to reduce blurring and blurring of display reflected by the light reflecting surface 31a.

  It is also possible to prepare the optical mirror 20 by separately preparing a light reflection film in addition to the electrode layer 31 and arranging the light reflection film on one side of the electrode layer 31. In this case, it is necessary to deform the light reflecting film together with the electrode layer 31 by bending the electrolyte layer 30. For this reason, the force for deforming the electrolyte layer 30 itself may be insufficient.

  On the other hand, in this embodiment, as described above, the electrode layer 31 is polished on one side of the constituent metal film to form the light reflecting surface 31a. For this reason, it is not necessary to deform both the electrode layer 31 and the light reflecting film by bending the electrolyte layer 30. Therefore, sufficient force can be used to deform the electrolyte layer 30. Thereby, it is possible to ensure a sufficient deformation rate of the electrolyte layer 30 while ensuring a sufficient deformation amount of the electrolyte layer 30. Furthermore, since it is not necessary to use a light reflecting film other than the electrode layer 31, the optical mirror 20 can be reduced in weight.

(Other embodiments)
In the above-described embodiment, the example in which the power sources 50a to 50d are provided for the actuators 40a to 40d as the head-up display 1 has been described, but instead of this, as illustrated in FIG. One common power supply 50 may be provided.

  In this case, among the actuators 40a, 40b, 40c, and 40d, the switch to be turned on among the switches 51a, 51b, 51c, and 51d is sequentially switched in order to sequentially switch the actuator charged from the power source 50.

  In the above embodiment, the example in which the actuators 40a to 40d are charged by the power sources 50a to 50d and the actuators 40a to 40d are deformed has been described. Instead, the actuators 40a to 40d are discharged to the power sources 50a to 50d. Thus, the actuators 40a to 40d may be deformed. Hereinafter, a specific example of the discharge process in the control circuit 54 will be described. The discharge process is a process for discharging the actuator 40a from the power source 50a to deform the actuator 40a.

  First, similarly to the above embodiment, after charging the actuator 40a and the capacitor 52a from the power supply 50a, the control circuit 54 turns off the switch 51a. Thereafter, the control circuit 54 controls the power supply 50a to make the output voltage of the power supply 50a lower than the voltage between the electrode layers 31 and 32 (and the voltage between both electrodes of the capacitor 52a), and turns on the switch 51a. . Accordingly, a current flows from the capacitor 52a to the power supply 50a through the resistance element 53a and the switch 51a. A current flows from the electrode layer 32 side of the actuator 40a to the power supply 50a through the resistance element 53a and the switch 51a. For this reason, the voltage between the electrode layers 31 and 32 falls. Therefore, in the actuator 40a, the corresponding electrolyte layer 301 is deformed together with the upper electrode portion and the opposite electrode layer 32. Accordingly, the degree of bending of the actuator 40a is reduced. The same applies to the actuators 40c to 40d.

  In the above embodiment, the example in which the electrode layer 31 is a common electrode layer for the actuators 40a to 40d has been described. However, instead of this, the electrode layer 31 may be independent for each actuator.

  In the above embodiment, the example in which the actuators 40a to 40d that bend the electrolyte layer 30 by the movement of the cation in the electrolyte layer 30 has been described has been described. Instead, the electrolyte is moved by the movement of the anion in the electrolyte layer 30. Actuators 40a to 40d that bend the layer 30 may be configured.

  In the above-described embodiment, the example in which the electrolyte layer 30 is a common electrode layer for the actuators 40a to 40d has been described. However, instead of this, the electrolyte layer 30 may be independent for each actuator.

  In the above embodiment, an example in which the planar display light output from the display device 10 is reflected by the shape variable optical element 20 has been described, but instead, the linear display light output from the display device 10 is used. The variable shape optical element 20 may be reflected.

  In the above embodiment, an example in which the four opposite electrode layers 32, 33, 34, and 35 are arranged on the opposite surface 30 b of the electrolyte layer 30 has been described, but the present invention is not limited to this, and n electrode layers are formed on the electrolyte layer 30. You may arrange | position to the opposite surface 30b. However, n is an integer of 2 or more. Alternatively, only one opposite electrode layer may be disposed on the opposite surface 30 b of the electrolyte layer 30. That is, in the present invention, the number of opposite surface electrode layers is not limited to four.

  In the above-described embodiment, the example in which the reflected light of the optical mirror 20 is output to the front windshield 21 as the head-up display 1 has been described, but instead of this, the side windshield and the backwindshield other than the front windshield 21 are optically connected. The reflected light of the mirror 20 may be output.

  In the above embodiment, the example in which the optical mirror 20 according to the present invention is applied to the head-up display 1 has been described. Instead, the optical mirror 20 according to the present invention is applied to various optical devices such as a microscope and a telescope. May be.

  In the above-described embodiment, the example in which the voltages are sequentially applied to the actuators 40a to 40d one by one has been described. However, instead of this, the voltages may be simultaneously applied to all the actuators 40a to 40d. Furthermore, a plurality of optical mirrors 20 may be arranged, and a voltage may be applied to the plurality of optical mirrors 20 in order, or a voltage may be applied to all of the plurality of optical mirrors 20 simultaneously.

  In addition, this invention is not limited to above-described embodiment, In the range described in the claim, it can change suitably.

DESCRIPTION OF SYMBOLS 1 Head-up display 20 Optical mirror 30 Electrolyte layer 31 Single-sided electrode layer 31a Light reflecting surface 32-35 Opposite side electrode layer 40a-40d Actuator 50a, 50b, 50c, 50d Power supply 51a, 51b, 51c, 51d Switch 52a, 52b, 52c , 52d capacitor 53a, 53b, 53c, 53d resistance element 54 control circuit

Claims (6)

An electrolyte membrane (30) made of an ion exchange resin, a first electrode layer (31) formed along one side of the electrolyte membrane, and the electrolyte membrane located on the opposite side of the one side And a second electrode layer (32-35) formed along the opposite surface, when a voltage is applied between the first and second electrode layers from a power source (50a-50d). An actuator (40a to 40d) in which ions move in the electrolyte membrane by an electric field between the first and second electrode layers and the electrolyte membrane bends together with the first and second electrode layers;
Capacitors (52a to 52d) connected in parallel to the actuator between the positive electrode and the negative electrode of the power source and having a capacitance larger than the capacitance of the actuator;
Switches (51a-51d) connected between common connection terminals (41a-41d) between the actuator and the capacitor and the power source;
A control circuit (54) for performing a charging process for turning off the switch before the actuator is fully charged after the actuator is turned on from the power source and charging the actuator and the capacitor is completed.
The time constant of the first charging circuit composed of the power source, the switch, and the capacitor is smaller than the time constant of the second charging circuit composed of the power source, the switch, and the actuator. A variable shape element characterized by comprising: A plurality of the second electrode layers are disposed on the opposite surface side of the electrolyte membrane,
The actuator composed of the first and second electrode layers and the electrolyte membrane is configured for each of the second electrode layers;
The capacitor and the switch are provided for each actuator,
The variable shape element according to claim 1, wherein the control circuit executes the charging process for each actuator.   During the period when one of the respective switches is turned off and the capacitor corresponding to the one switch is charging the actuator corresponding to the capacitor, the control circuit is configured so that the control circuit includes the switch. 3. The variable shape element according to claim 2, wherein a switch other than one switch is turned on to start charging of the actuator and the capacitor corresponding to the other switch from the power source.   The light reflecting surface (31a) is disposed on the opposite side of the electrolyte membrane with respect to any one of the first and second electrode layers. The shape variable element according to any one of the above. The variable shape element according to claim 4 , wherein the light reflecting surface is configured by one of the first and second electrode layers. A variable shape element (20) according to claim 4 or 5,
A display device (10) for outputting display light,
The light reflecting surface reflects display light output from the display device toward the windshield (21),
The automobile head-up display, wherein the actuator bends the light reflecting surface by bending the electrolyte membrane together with the first and second electrode layers.

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