Optical deflector driving system and optical deflector driving method

Abstract

An optical deflector drive system, etc., is provided that can prevent abnormal oscillations in the optical deflector even when reflecting changes in offset (or amplitude). The invention includes: a change command input step (S20) for inputting a command to change at least one of a first drive signal corresponding to a first drive voltage and a second drive signal corresponding to a second drive voltage, the first and second drive voltages being applied to an actuator that oscillates the mirror portion of the optical deflector around a swing axis; a determination step (S21, S23) for determining a timing when the voltage of the drive signal to be changed is at its minimum among the first and second drive signals after the command has been input; and a change reflection step (S25, S27) for reflecting the change in the drive signal to be changed when the timing is determined to be at its minimum voltage.

Description

Technical Field

[0001] The present invention relates to an optical deflector driving system and an optical deflector driving method, and more specifically, to an optical deflector driving system and an optical deflector driving method that can prevent abnormal oscillations in the optical deflector (thereby preventing striped patterns in the image drawn by the light scanned by the optical deflector) even when reflecting changes in offset (or amplitude). Background Technology

[0002] An image projection system is known that offsets a drive signal (drive voltage) applied to an optical deflector (actuator) to change the position (offset) of an image drawn by light scanned by the optical deflector in the vertical direction (see, for example, Patent Document 1).

[0003] Citation List

[0004] Patent documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-54752 Summary of the Invention

[0006] Technical issues

[0007] However, as a result of their research, the inventors discovered that in the system disclosed in Patent Document 1, when the timing reflects the change in offset (or amplitude) when the instruction for changing the offset (or amplitude) is input, the waveform of the drive signal (drive voltage) is disturbed before and after the change. Abnormal oscillations occur in the optical deflector due to unwanted frequency components (unintentional frequency components) included in the edges of the drive signal (drive voltage) with the disturbed waveform. This causes striped patterns to appear in the image drawn by the light scanned by the optical deflector.

[0008] The present invention, proposed to solve such problems, aims to provide an optical deflector driving system and an optical deflector driving method that can prevent abnormal oscillations in the optical deflector even in the case of changes in offset (or amplitude) (thereby preventing striped patterns in the image drawn by the light scanned by the optical deflector).

[0009] Technical solution

[0010] The optical deflector drive system according to the present invention includes: a mirror portion, a first support portion configured to support the mirror portion, a second support portion configured to support the first support portion, and at least one actuator configured to oscillate the first support portion relative to the second support portion about a swing axis. The actuator includes a plurality of piezoelectric cantilever arms disposed in the direction of the swing axis. The plurality of piezoelectric cantilever arms are connected in a bellows shape such that each of the piezoelectric cantilever arms is folded back relative to its adjacent piezoelectric cantilever arm. The free end of the piezoelectric cantilever arm on the mirror portion side is connected to the first support portion. The free end of the piezoelectric cantilever arm on the second support portion side is connected to the second support portion. The optical deflector drive system applies a first drive voltage corresponding to a first drive signal to an even-numbered piezoelectric cantilever arm counted from the mirror portion to bend and deform the even-numbered piezoelectric cantilever arm, and applies a second drive voltage corresponding to a second drive signal to an odd-numbered piezoelectric cantilever arm counted from the mirror portion to bend and deform the odd-numbered piezoelectric cantilever arm. The optical deflector drive system includes: a timing determination unit configured to determine a timing when the voltage of the drive signal to be changed becomes the minimum when an instruction for changing at least one of the first drive signal and the second drive signal is input; and a change response unit configured to reflect the change on the drive signal to be changed when the timing for determining that the voltage of the drive signal to be changed becomes the minimum arrives.

[0011] With this configuration, even in cases that reflect changes in offset (or amplitude), abnormal oscillations in the optical deflector can be prevented (thus preventing striped patterns from appearing in the image drawn by the light scanned by the optical deflector).

[0012] This is because the change in offset (or amplitude) is not reflected at the timing when the command for changing the offset (or amplitude) is input. Instead, the change in offset (or amplitude) is reflected in the drive signal to be changed when the timing arrives at the time when the voltage of the drive signal to be changed becomes the minimum. This allows unwanted frequency components (unintentional frequency components) that cause abnormal oscillations in the optical deflector to be removed.

[0013] Furthermore, in the aforementioned optical deflector drive system, the command can be a command for changing the amplitude.

[0014] Furthermore, in the aforementioned optical deflector drive system, the command can be a command for changing the offset.

[0015] In addition, the aforementioned optical deflector drive system may also include an offset division unit, the instruction of which may be offset level data indicating the offset amount, the offset division unit may divide the offset amount by the rise time or fall time, and the change response unit may reflect the change in the drive signal to be changed in a step manner whenever the divided time has elapsed.

[0016] The optical deflector driving method according to the present invention includes the following steps: a change command input step, wherein the step inputs a command for changing at least one of a first driving signal corresponding to a first driving voltage and a second driving signal corresponding to a second driving voltage, the first driving voltage and the second driving voltage being applied to an actuator that causes the mirror portion of the optical deflector to oscillate around a swing axis; a determination step, wherein, upon the input of the command, the step determines a timing at which the voltage of the driving signal to be changed among the first driving signal and the second driving signal becomes minimum; and a change response step, wherein, upon the arrival of the timing at which the voltage of the driving signal to be changed becomes minimum, the change is reflected in the driving signal to be changed.

[0017] With this configuration, even in cases that reflect changes in offset (or amplitude), abnormal oscillations in the optical deflector can be prevented (thus preventing striped patterns from appearing in the image drawn by the light scanned by the optical deflector).

[0018] This is because the change in offset (or amplitude) is not reflected at the timing when the command for changing the offset (or amplitude) is input. Instead, the change in offset (or amplitude) is reflected in the drive signal to be changed when the timing arrives at the time when the voltage of the drive signal to be changed becomes the minimum. This allows unwanted frequency components (unintentional frequency components) that cause abnormal oscillations in the optical deflector to be removed.

[0019] Furthermore, in the aforementioned optical deflector driving method, the command can be a command for changing the amplitude.

[0020] Furthermore, in the aforementioned optical deflector driving method, the command can be a command for changing the offset.

[0021] In addition, the above-mentioned optical deflector driving method may also include an offset division step, the instruction of which may be offset level data indicating the offset amount, the offset amount may be divided by the rise time or fall time in the offset division step, and in the change response step, the change may be reflected in the drive signal to be changed in a step manner whenever the divided time has elapsed.

[0022] Technical effects of the invention

[0023] According to the present invention, an optical deflector driving system and an optical deflector driving method can be provided that can prevent abnormal oscillations in the optical deflector even in the case of changes in offset (or amplitude) (thereby preventing striped patterns in the image drawn by the light scanned by the optical deflector). Attached Figure Description

[0024] Figure 1This is a schematic configuration diagram of an optical deflector drive system 10 according to an embodiment of the present invention;

[0025] Figure 2 This is a perspective view of a single-axis non-resonant / single-axis resonant optical deflector 1;

[0026] Figure 3A It is an example shown along Figure 2 A diagram of the end surface of the optical deflector taken from line IIIA-IIIA;

[0027] Figure 3B It is an example shown along Figure 2 A diagram of the end surface of the optical deflector taken from line IIIB-IIIB;

[0028] Figure 4 Examples of the third drive voltage Vx1 (drive signal P) and the fourth drive voltage Vx2 (drive signal N) are shown;

[0029] Figure 5A This is a diagram showing the piezoelectric actuator of the optical deflector in a non-operating state;

[0030] Figure 5B This is a diagram showing the operating state of the piezoelectric actuator of the optical deflector;

[0031] Figure 6 This is a diagram showing the state in which an image P is drawn on a screen member 20 using a laser beam Ray scanned by an optical deflector 1 (raster scan) (illustrations of the condenser lens 14, the correction mirror 18, and the projection lens 23 are omitted).

[0032] Figure 7 This shows the driving voltage applied to optical deflector 1 (see [reference]). Figure 7 (a) and the swing angle of mirror part 2 (see Figure 7 A diagram showing the relationship between (b) and (b);

[0033] Figure 8 Examples of images P with different vertical widths drawn on screen component 20 are shown;

[0034] Figure 9 Examples of images P drawn on screen component 20 at different positions (offsets) in the vertical direction are shown;

[0035] Figure 10 An example of a functional configuration of the optical deflector drive system 10 is shown;

[0036] Figure 11 An example of the functional configuration of the image signal processing unit 116 is shown;

[0037] Figure 12 This is a sequence diagram of the process by which the mirror part 2 swings around the second axis X using the MEMS drive unit 108;

[0038] Figure 13 An example of the signal (time plot) is shown when the vertical width of image P decreases;

[0039] Figure 14 It is a diagram explaining the problem discovered by the inventor;

[0040] Figure 15 It is a diagram explaining the problem discovered by the inventor;

[0041] Figure 16 This is a sequence diagram of the process of changing the vertical width of the image drawn on the screen component 20 while preventing abnormal oscillations in the optical deflector 1.

[0042] Figure 17 This is a sequence diagram of the process of changing the offset of the image drawn on the screen component 20 while preventing abnormal oscillations in the optical deflector 1.

[0043] Figure 18 An example of the signal (time plot) is shown when image P is shifted upwards.

[0044] Figure 19 This is an enlarged view of the area surrounded by the dashed circle of the fifth signal N;

[0045] Figure 20 An example of the signal (time plot) is shown when the vertical width of image P increases;

[0046] Figure 21 An example of the signal (time plot) is shown when image P is shifted downwards; and

[0047] Figure 22 This is a diagram illustrating a variation of the fifth signal. Detailed Implementation

[0048] An optical deflector drive system 10 according to an embodiment of the present invention will now be described with reference to the accompanying drawings. Corresponding components in the drawings are indicated by the same reference numerals, and repeated descriptions are omitted.

[0049] Figure 1 This is a schematic configuration diagram of an optical deflector drive system 10 according to an embodiment of the present invention.

[0050] like Figure 1As shown, the optical deflector drive system 10 includes a light source 12, a condenser lens 14 for focusing light (e.g., a laser beam) emitted from the light source 12, a correction mirror 18, an optical deflector 1 for performing two-dimensional scanning (in both the horizontal and vertical directions) using a laser beam Ray focused by the condenser lens 14 and reflected by the correction mirror 18, a screen member 20 for drawing an image thereon using the laser beam Ray scanned by the optical deflector 1, and a projection lens 23 for projecting the image drawn on the screen member 20, etc. Note that the optical deflector drive system 10 can have any configuration as long as it includes an optical deflector for drawing an image by performing scanning using light emitted from the light source 12.

[0051] The light source 12 is, for example, a laser diode (LD), which emits a laser beam with an emission wavelength in the blue region. The laser beam from the light source 12 is focused (e.g., collimated) by a condenser lens 14, reflected by a correction mirror 18, and then enters the optical deflector 1 (mirror section 2). The correction mirror 18 is provided to prevent image distortion drawn on the screen member 20. The correction mirror 18 can be omitted.

[0052] Optical deflector 1 performs two-dimensional scanning (in both the horizontal and vertical directions) using a laser beam focused by condenser lens 14. An image is drawn on screen member 20 using the laser beam scanned by optical deflector 1. Screen member 20 is, for example, a fluorescent panel with a rectangular plate shape. The fluorescent panel is a wavelength conversion member that converts at least a portion of the laser beam Ray scanned by optical deflector 1 into beams with different wavelengths (e.g., the beam in the yellow area). The image drawn on screen member 20 is projected by projection lens 23.

[0053] Optical deflectors 1 are, for example, MEMS scanners. The main methods for driving optical deflectors include piezoelectric, electrostatic, and electromagnetic methods, and any of these methods is acceptable. Furthermore, piezoelectric methods are broadly classified into single-axis non-resonant / single-axis resonant types, dual-axis non-resonant types, and dual-axis resonant types, and any of these types is acceptable.

[0054] In the following text, an optical deflector 1 of piezoelectric type (uniaxial non-resonant / uniaxial resonant type) is described as a representative example.

[0055] Figure 2 This is a perspective view of a single-axis non-resonant / single-axis resonant optical deflector 1.

[0056] The optical deflector 1 includes a mirror portion 2, a pair of first piezoelectric actuators 31 and 32, a first support portion 4, a pair of second piezoelectric actuators 51 and 52, and a second support portion 6. The optical deflector 1 can have any configuration, as long as unintentional abnormal oscillations (abnormal resonances) occur in the optical deflector 1 when responding to changes in offset (or amplitude) in response to a drive signal (drive voltage).

[0057] The mirror part 2 includes a reflective surface 2a having a circular shape and reflecting incident light, and a reflective surface support 2b having a circular shape and supporting the reflective surface 2a.

[0058] The reflective surface support 2b is formed from a silicon substrate. Pairs of torsion bars 21 and 22 extending outward from both ends of the reflective surface support 2b are connected to the reflective surface support 2b.

[0059] The first piezoelectric actuators 31 and 32 are each formed in a semi-circular arc shape and are spaced apart to surround the mirror portion 2. One end of each of the first piezoelectric actuators 31 and 32 is connected to each other oppositely, and a torsion bar 21 is between one end of each of the first piezoelectric actuators 31 and 32. The other ends of each of the first piezoelectric actuators 31 and 32 are connected to each other oppositely, and another torsion bar 22 is between the other ends of each of the first piezoelectric actuators 31 and 32.

[0060] The first support portion 4 is formed in the shape of a rectangular frame and is configured to surround the mirror portion 2 and the first piezoelectric actuators 31 and 32. The first support portion 4 is connected to the outer side of the center position of the arc portion of the first piezoelectric actuators 31 and 32, and supports the mirror portion 2 through the first piezoelectric actuators 31 and 32.

[0061] The second piezoelectric actuators 51 and 52 are disposed opposite to each other, and the first support portion 4 is located between the second piezoelectric actuators 51 and 52. The front ends of the second piezoelectric actuators 51 and 52 are connected to the paired sides of the first support portion 4 in a direction orthogonal to the torsion bars 21 and 22.

[0062] The second support portion 6 is formed in a rectangular frame shape and is configured to surround the first support portion 4 and the second piezoelectric actuators 51 and 52. The ends of the second piezoelectric actuators 51 and 52 that are not connected to the first support portion 4 are connected to the second support portion 6. Therefore, the second support portion 6 supports the first support portion 4 through the second piezoelectric actuators 51 and 52.

[0063] Next, the detailed configuration of the first piezoelectric actuators 31 and 32 is described. The first piezoelectric actuators 31 and 32 each include a first piezoelectric cantilever 31A and 32A, respectively configured to bend and deform due to piezoelectric actuation. More specifically, one of the first piezoelectric actuators 31 and 32, 31, includes a first piezoelectric cantilever 31A, and the other first piezoelectric actuator 32 includes another first piezoelectric cantilever 32A. The first piezoelectric actuators 31 and 32 can cause the mirror portion 2 to oscillate relative to the first support portion 4 about the first axis Y via torsion bars 21 and 22 due to the bending deformation of the first piezoelectric cantilever 31A and 32A.

[0064] Next, the detailed configuration of the second piezoelectric actuators 51 and 52 is described. The second piezoelectric actuators 51 and 52 each include a pair of second piezoelectric cantilever arms 51A to 51D and 52A to 52D, each configured to bend and deform due to piezoelectric actuation. More specifically, one of the pairs of second piezoelectric actuators 51 and 52, the second piezoelectric actuator 51, includes one side of the four piezoelectric cantilever arms 51A to 51D. The other second piezoelectric actuator 52 of the pair of second piezoelectric actuators 51 and 52 includes the other side of the four piezoelectric cantilever arms 52A to 52D.

[0065] The two ends of the second piezoelectric cantilever arms 51A to 51D on one side are adjacent to each other, such that their length directions point in the same direction. Furthermore, the second piezoelectric cantilever arms 51A to 51D on one side are arranged side-by-side at predetermined intervals so that the mirror portion 2 swings about a second axis X (an axis orthogonal to the first axis Y; however, the second axis X does not need to be precisely orthogonal to the first axis Y). The second piezoelectric cantilever arms 51A to 51D on one side are connected such that each of the second piezoelectric cantilever arms 51A to 51D folds back relative to the adjacent piezoelectric cantilever arm. The second axis X is an example of the swing axis according to the invention.

[0066] Similar to the second piezoelectric cantilever arms 51A to 51D on one side, the two ends of the second piezoelectric cantilever arms 52A to 52D on the other side are adjacent to each other, such that their length directions point in the same direction. Furthermore, the second piezoelectric cantilever arms 52A to 52D on the other side are arranged side-by-side at predetermined intervals so that the mirror portion 2 swings about the second axis X. The second piezoelectric cantilever arms 52A to 52D on the other side are connected such that each of the second piezoelectric cantilever arms 52A to 52D folds back relative to the adjacent piezoelectric cantilever arm.

[0067] As described above, in one second piezoelectric actuator 51 and the other second piezoelectric actuator 52, one side of the second piezoelectric cantilever 51A to 51D and the other side of the second piezoelectric cantilever 52A to 52D of the second second piezoelectric actuator 51 and the other second piezoelectric actuator 52 are formed in a so-called tortuous shape (or bellows shape).

[0068] Among the second piezoelectric arms 51A to 51D on one side and the second piezoelectric arms 52A to 52D on the other side, the ends (free ends) of the piezoelectric arms (hereinafter referred to as "1-2 piezoelectric arms") 51A and 52A provided on the mirror part 2 side (first support part 4 side), which are not connected to their respective adjacent second piezoelectric arms (hereinafter referred to as "2-2 piezoelectric arms") 51B and 52B, are connected to the outer periphery of the first support part 4.

[0069] Similarly, among the second piezoelectric cantilever arms 51A to 51D on one side and the second piezoelectric cantilever arms 52A to 52D on the other side, the ends (free ends) of the piezoelectric cantilever arms (hereinafter referred to as "4-2 piezoelectric cantilever arms") 51D and 52D provided on the side of the second support portion 6 that are not connected to their respective adjacent second piezoelectric cantilever arms (hereinafter referred to as "3-2 piezoelectric cantilever arms") 51C and 52C are connected to the inner periphery of the second support portion 6.

[0070] Therefore, the first support portion 4 can swing about the second axis X relative to the second support portion 6 due to the bending deformation of the second piezoelectric cantilevers 51A to 51D and 52A to 52D that constitute the second piezoelectric actuators 51 and 52.

[0071] In the following text, among the pairs of piezoelectric arms 51A to 51D and 52A to 52D, the piezoelectric arms arranged in odd numbers starting from the mirror part 2 (piezoelectric arms 1-2 51A and 52A, and piezoelectric arms 3-2 51C and 52C) are referred to as the odd-numbered second piezoelectric arms 51A, 51C, 52A and 52C.

[0072] Furthermore, among the odd-numbered second piezoelectric arms 51A, 51C, 52A, and 52C, the odd-numbered second piezoelectric arms included in one side of the second piezoelectric arms 51A to 51D are referred to as the odd-numbered second piezoelectric arms 51A and 51C on one side, and the odd-numbered second piezoelectric arms included in the other side of the second piezoelectric arms 52A to 52D are referred to as the odd-numbered second piezoelectric arms 52A and 52C on the other side.

[0073] Similarly, among the pairs of second piezoelectric arms 51A to 51D and 52A to 52D, the piezoelectric arms arranged in even numbers starting from the mirror part 2 (2-2 piezoelectric arms 51B and 52B, and 4-2 piezoelectric arms 51D and 52D) are referred to as the even-numbered second piezoelectric arms 51B, 51D, 52B and 52D.

[0074] Furthermore, among the even-numbered second piezoelectric arms 51B, 51D, 52B, and 52D, the even-numbered second piezoelectric arms included in one side of the second piezoelectric arms 51A to 51D are referred to as the even-numbered second piezoelectric arms 51B and 51D on one side, and the even-numbered second piezoelectric arms included in the other side of the second piezoelectric arms 52A to 52D are referred to as the even-numbered second piezoelectric arms 52B and 52D on the other side.

[0075] Figure 3A and Figure 3B This is a schematic end view of the optical deflector 1. Figure 3A It is along Figure 2 The end view taken from line IIIA-IIIA in the diagram. However, in Figure 3A The illustration of the second support part 6 is omitted in the text. Figure 3B It is along Figure 2 The end view taken from line IIIB-IIIB in the diagram. However, in Figure 3B The illustrations of the second support 6 and piezoelectric arms 51C and 52C and 51D and 52D of the pairs of second piezoelectric arms 51A to 51D and 52A to 52D are omitted.

[0076] Each of the 3-2 piezoelectric cantilever 51C and 52C has the same configuration as each of the 1-2 piezoelectric cantilever 51A and 52A. Similarly, each of the 4-2 piezoelectric cantilever 51D and 52D has the same configuration as each of the 2-2 piezoelectric cantilever 51B and 52B.

[0077] Each of the first piezoelectric cantilever 31A and 32A constituting the first piezoelectric actuator 31 and 32 and the paired second piezoelectric cantilever 51A to 51D and 52A to 52D constituting the second piezoelectric actuator 51 and 52 is a piezoelectric cantilever with a structure in which the lower electrode L1, the piezoelectric body L2 and the upper electrode L3 are stacked on a layer of support B, which serves as the strain (cantilever body).

[0078] As detailed in the structure of each piezoelectric cantilever, a lower electrode L1, a piezoelectric body L2, and an upper electrode L3 are stacked on a layer of support B, and an interlayer insulating film M1 is configured to surround the lower electrode L1, the piezoelectric body L2, and the upper electrode L3. Furthermore, an upper electrode wire W is stacked on the interlayer insulating film M1, and a passivation film M2 is configured to surround the upper electrode wire W.

[0079] Note that, as described below, the upper electrode wire W includes a first driving upper electrode wire Wy, a second driving upper electrode wire Wo for odd-numbered uses, a second driving upper electrode wire We for even-numbered uses, a first detection upper electrode wire Wmy, and a second detection upper electrode wire Wmx, and the wire is referred to as the upper electrode wire W unless otherwise specified.

[0080] When a driving voltage is applied between the upper electrode L3 and the lower electrode L1, the piezoelectric element L2 of each of the piezoelectric cantilever arms 31A, 32A, 51A to 51D, and 52A to 52D bends and deforms due to piezoelectric actuation. The bending and deformation of each of the piezoelectric cantilever arms 31A, 32A, 51A to 51D, and 52A to 52D is accompanied by the bending and deformation of the corresponding piezoelectric element L2.

[0081] Note that at the connection between each of the pairs of second piezoelectric arms 51A to 51D and 52A to 52D constituting the second piezoelectric actuators 51 and 52 and the adjacent piezoelectric arm, the support body B of the adjacent piezoelectric arm is integrally connected, and the piezoelectric body L2 and the upper electrode L3 are not provided at the connection.

[0082] The first detection units 71y and 72y and the second detection units 71x and 72x are disposed on the first support portion 4. The first detection units 71y and 72y are disposed on the first support portion 4 at the center of the side portion of the first support portion 4 that is parallel to the second axis X (the side portion that is orthogonal to the side portion of the second piezoelectric cantilever 51A to 51D and 52A to 52D in the length direction).

[0083] The second detection units 71x and 72x are disposed on the first support 4 at the center of the side portion of the first support 4 parallel to the first axis Y. The first detection units 71y and 72y and the second detection units 71x and 72x are disposed separately from each other in a plane.

[0084] The first detection units 71y and 72y are configured as sensors that detect a first oscillation transmitted to the first support portion 4 when the mirror portion 2 oscillates relative to the first support portion 4 about a first axis Y due to the piezoelectric drive of the first piezoelectric actuators 31 and 32. The second detection units 71x and 72x are configured as sensors that detect a second oscillation transmitted to the first support portion 4 when the first support portion 4 oscillates relative to the second support portion 6 about a second axis X due to the piezoelectric drive of the second piezoelectric actuators 51 and 52.

[0085] Similar to the first piezoelectric cantilever arms 31A and 32A and the second piezoelectric cantilever arms 51A to 51D and 52A to 52D, each of the first detection units 71y and 72y and the second detection units 71x and 72x has a structure in which the lower electrode L1, the piezoelectric body L2, and the upper electrode L3 are stacked on the layer of the support body B constituting the first support portion 4. In each of the first detection units 71y and 72y and the second detection units 71x and 72x, the interlayer insulating film M1, the upper electrode wire W, and the passivation film M2 are configured to be the same as those in each of the piezoelectric cantilever arms 31A, 32A, 51A to 51D, and 52A to 52D.

[0086] Furthermore, when the first support portion 4 bends and deforms due to the transmission of the first or second oscillation to the first support portion 4, the piezoelectric element L2 of each of the first detection units 71y and 72y and the second detection units 71x and 72x outputs a voltage corresponding to the amount of deformation caused by the bending deformation. The optical deflector 1 can detect the oscillation transmitted to the first support portion 4 based on the voltage value at this time.

[0087] Previous experiments have shown that in the first support portion 4 of the optical deflector 1 according to this embodiment, when the mirror portion 2 swings around the first axis Y, the central portions on both sides parallel to the second axis X are prone to bending and deformation. Therefore, the first detection units 71y and 72y are provided at the central portions on the corresponding sides. Furthermore, previous experiments have shown that when the first support portion 4 swings around the second axis X, the central portions on both sides parallel to the first axis Y are prone to bending and deformation. Therefore, the second detection units 71x and 72x are provided at the central portions on the corresponding sides.

[0088] The optical deflector 1 includes lower electrode pads 61a and 62a, first upper electrode pads 61b and 62b, odd-numbered second upper electrode pads 61c and 62c, even-numbered second upper electrode pads 61d and 62d, first detection electrode pad 61e, and second detection electrode pad 62e on the second support portion 6.

[0089] One of the lower electrode pads 61a and 62a, 61a, is electrically connected to the lower electrode L1 of a first piezoelectric cantilever 31A, the lower electrode L1 of one side of a second piezoelectric cantilever 51A to 51D, and the lower electrode L1 of the first detection units 71y and 72y. The other lower electrode pad 62a is electrically connected to the lower electrode L1 of another first piezoelectric cantilever 32A, the lower electrode L1 of the other side of a second piezoelectric cantilever 52A to 52D, and the lower electrode L1 of the second detection units 71x and 72x.

[0090] As described above, the lower electrode pads 61a and 62a serve as electrode pads shared by the first piezoelectric actuators 31 and 32, the second piezoelectric actuators 51 and 52, the first detection units 71y and 72y, and the second detection units 71x and 72x.

[0091] One of the first upper electrode pads 61b and 62b, the first upper electrode pad 61b, is electrically connected to the upper electrode L3 of a first piezoelectric cantilever 31A. The other first upper electrode pad 62b is electrically connected to the upper electrode L3 of another first piezoelectric cantilever 32A.

[0092] One of the odd-numbered application upper electrode pads 61c and 62c, the odd-numbered application second upper electrode pad 61c, is electrically connected to the upper electrode L3 of the odd-numbered second piezoelectric cantilever 51A and 51C on one side. The other odd-numbered application second upper electrode pad 62c, of the odd-numbered application second upper electrode pads 61c and 62c, is electrically connected to the upper electrode L3 of the other odd-numbered second piezoelectric cantilever 52A and 52C.

[0093] One of the even-numbered second upper electrode pads 61d and 62d is electrically connected to the upper electrode L3 of the even-numbered second piezoelectric cantilever 51B and 51D on one side. The other even-numbered second upper electrode pad 62d is electrically connected to the upper electrode L3 of the even-numbered second piezoelectric cantilever 52B and 52D on the other side.

[0094] The first detection electrode pad 61e is electrically connected to the upper electrode L3 of the first detection units 71y and 72y. The second detection electrode pad 62e is electrically connected to the upper electrode L3 of the second detection units 71x and 72x.

[0095] With the aforementioned electrical connection, when a driving voltage is applied between the upper electrode L3 and the lower electrode L1, the piezoelectric element L2 stacked between the upper electrode L3 and the lower electrode L1, under the applied driving voltage, bends and deforms due to piezoelectric drive. As a result, the support B (piezoelectric cantilever) corresponding to the bent and deformed piezoelectric element L2 bends and deforms.

[0096] Furthermore, as described below, in the first support portion 4, the voltages generated from the first detection units 71y and 72y due to the piezoelectric effect derived from the bending deformation caused by the transmitted oscillations are each output as a potential difference between the first detection electrode pad 61e and the lower electrode pad 61a. Similarly, the voltages generated from the second detection units 71x and 72x due to the piezoelectric effect derived from the bending deformation of the first support portion 4 are each output as a potential difference between the second detection electrode pad 62e and the lower electrode pad 61a.

[0097] The paired lower electrode pads 61a and 62a, the first piezoelectric cantilever 31A and 32A, the second piezoelectric cantilever 51A to 51D and 52A to 52D, and the lower electrodes L1 of the first detection units 71y and 72y and the second detection units 71x and 72x are each formed on a silicon substrate by shaping a metal thin film (in this embodiment, a two-layer metal thin film, hereinafter also referred to as the lower electrode layer) using a semiconductor planarization process. The material of the metal thin film is, for example, titanium (Ti), titanium dioxide (TiO2), or titanium oxide (TiO2), which has a controllable oxidation amount. x Platinum (Pt), LaNiO3, or SrRuO3 are used for the first layer (lower layer), and platinum (Pt), LaNiO3, or SrRuO3 are used for the second layer (upper layer).

[0098] In this configuration, the lower electrode L1 of the first piezoelectric cantilever 31A and 32A is formed above substantially the entire surface of the support body B of the first piezoelectric cantilever 31A and 32A. The lower electrode L1 of the second piezoelectric cantilever 51A to 51D and 52A to 52D is formed above substantially the entire surface of the support body B of the second piezoelectric cantilever 51A to 51D and 52A to 52D (including the entire straight portion and connecting portion of each piezoelectric cantilever).

[0099] The lower electrodes L1 of the first detection units 71y and 72y are formed on the support body B of the first support portion 4 on the portion where the first detection units 71y and 72y are disposed. The lower electrodes L1 of the second detection units 71x and 72x are formed on the support body B of the first support portion 4 on the portion where the second detection units 71x and 72x are disposed. Similarly, the lower electrodes L1, the interlayer insulating film M1, the upper electrode wire W, and the passivation film M2 are also disposed on the second support portion 6.

[0100] The lower electrode pads 61a and 62a are connected to the lower electrodes L1 of the first piezoelectric cantilever 31A and 32A, the lower electrodes L1 of the second piezoelectric cantilever 51A to 51D and 52A to 52D, the lower electrodes L1 of the first detection units 71y and 72y, and the lower electrodes L1 of the second detection units 71x and 72x in the manner described above.

[0101] The piezoelectric bodies L2 of the first piezoelectric cantilever arms 31A and 32A, the second piezoelectric cantilever arms 51A to 51D and 52A to 52D, the first detection units 71y and 72y, and the second detection units 71x and 72x are independently formed on the lower electrode L1 of each piezoelectric cantilever arm by shaping a piezoelectric film (hereinafter also referred to as a piezoelectric body layer) on the lower electrode layer using a semiconductor planar process. For example, lead zirconate titanate (PZT) is used as the piezoelectric material for the piezoelectric film.

[0102] In this configuration, the piezoelectric element L2 of the first piezoelectric cantilever 31A and 32A is formed above substantially the entire surface of the lower electrode L1 of the first piezoelectric cantilever 31A and 32A. The piezoelectric element L2 of the second piezoelectric cantilever 51A to 51D and 52A to 52D is formed above substantially the entire surface of the lower electrode L1 in the extensions (straight sections) of the second piezoelectric cantilever 51A to 51D and 52A to 52D. The piezoelectric element L2 of the first detection units 71y and 72y is formed above substantially the entire surface of the lower electrode L1 of the first detection units 71y and 72y. The piezoelectric element L2 of the second detection units 71x and 72x is formed above substantially the entire surface of the lower electrode L1 of the second detection units 71x and 72x.

[0103] The "first upper electrode pads 61b and 62b, the odd-numbered second upper electrode pads 61c and 62c, the even-numbered second upper electrode pads 61d and 62d, the first detection electrode pad 61e and the second detection electrode pad 62e", the "first piezoelectric cantilever 31A and 32A, the second piezoelectric cantilever 51A to 51D and 52A to 52D, the upper electrode L3 of the first detection unit 71y and 72y and the second detection unit 71x and 72x", and the upper electrode wires W that connect these components are each formed on the piezoelectric layer by shaping a metal thin film (in this embodiment, a single metal thin film, hereinafter also referred to as the upper electrode layer) using a semiconductor planar process. The material of the metal thin film is, for example, platinum (Pt), gold (Au), aluminum (Al), or an aluminum alloy (Al alloy).

[0104] In this case, the upper electrode L3 of the first piezoelectric cantilever 31A and 32A, the second piezoelectric cantilever 51A to 51D and 52A to 52D, the first detection unit 71y and 72y, and the second detection unit 71x and 72x is formed above substantially the entire surface of the piezoelectric body L2 of the piezoelectric cantilever and the detection unit.

[0105] Furthermore, the first upper electrode pads 61b and 62b are connected to the upper electrodes L3 of the first piezoelectric cantilever 31A and 32A respectively via the first driving upper electrode wire Wy, as described above. Additionally, the odd-numbered second upper electrode pads 61c and 62c are connected to the upper electrodes L3 of the odd-numbered second piezoelectric cantilever 51A, 51C, 52A, and 52C via the second driving odd-numbered upper electrode wire Wo, as described above. Furthermore, the even-numbered second upper electrode pads 61d and 62d are connected to the upper electrodes L3 of the even-numbered second piezoelectric cantilever 51B, 51D, 52B, and 52D via the second driving even-numbered upper electrode wire We, as described above.

[0106] The first detection electrode pad 61e is connected to the upper electrode L3 of the first detection units 71y and 72y via the first detection upper electrode wire Wmy in the manner described above. Furthermore, the second detection electrode pad 62e is connected to the upper electrode L3 of the second detection units 71x and 72x via the second detection upper electrode wire Wmx in the manner described above.

[0107] like Figure 3A and Figure 3B As shown, the first driving upper electrode wire Wy, the second driving odd-numbered application upper electrode wire Wo, the second driving even-numbered application upper electrode wire We, the first detection upper electrode wire Wmy, and the second detection upper electrode wire Wmx are arranged to be separated from each other in a plane. Each upper electrode wire W is insulated by an interlayer insulating film M1 formed between the upper electrode wire W and the upper electrode L3. In order to conduct the upper electrode wire W to the upper electrode L3, a conductive member (e.g., an electrode via) is formed in the interlayer insulating film M1 to conduct the upper electrode wire W to the upper electrode L3.

[0108] Each passivation film M2 is formed on the corresponding upper electrode wire W using a semiconductor planarization process to surround the upper electrode wire W.

[0109] The reflective surface support 2b, torsion bars 21 and 22, support B, first support 4, and second support 6 are integrally formed by shaping a semiconductor substrate (silicon substrate) comprising multiple layers. Semiconductor planar processes and MEMS processes, such as photolithography and dry etching, are used as methods for performing the shaping of the semiconductor substrate.

[0110] Next, the operation of the optical deflector 1 according to this embodiment will be described. First, the case of the first piezoelectric actuators 31 and 32 that cause the mirror part 2 to swing relative to the first support part 4 about the first axis Y will be described.

[0111] In this configuration, the optical deflector 1 applies a driving voltage to the first piezoelectric actuators 31 and 32. More specifically, in one of the first piezoelectric actuators 31, a first driving voltage Vy1 is applied between a first upper electrode pad 61b and a lower electrode pad 61a to drive a piezoelectric cantilever 31A. In the other first piezoelectric actuator 32, a second driving voltage Vy2 is applied between another first upper electrode pad 62b and another lower electrode pad 62a to drive another first piezoelectric cantilever 32A. The first driving voltage Vy1 and the second driving voltage Vy2 are alternating current voltages (e.g., sine waves or sawtooth waves) that are out of phase or offset from each other.

[0112] At this time, the swing voltage components of the first driving voltage Vy1 and the second driving voltage Vy2 are applied, so that in the vertical direction of the first piezoelectric actuators 31 and 32 ( Figure 1(The upward direction U and the opposite downward direction in the middle), the angular displacement of one first piezoelectric cantilever 31A and the angular displacement of another first piezoelectric cantilever 32A are generated in opposite directions.

[0113] For example, in order to move a first piezoelectric actuator 31 upward when the mirror part 2 swings around the first axis Y, a first piezoelectric cantilever 31A is moved upward. In order to move a first piezoelectric actuator 31 downward, a first piezoelectric cantilever 31A is moved downward.

[0114] Similar to the first piezoelectric actuator 31, in order to shift the other first piezoelectric actuator 32 in the upward direction, the other first piezoelectric cantilever 32A is shifted in the upward direction. In order to shift the other first piezoelectric actuator 32 in the downward direction, the other first piezoelectric cantilever 32A is shifted in the downward direction.

[0115] In the optical deflector 1 according to this embodiment, when the mirror section 2 oscillates around the first axis Y, a large deflection angle is obtained by "moving one first piezoelectric actuator 31 upward and moving another first piezoelectric actuator 32 downward" or "moving one first piezoelectric actuator 31 downward and moving another first piezoelectric actuator 32 upward". As described above, in this embodiment, the mirror section 2 can oscillate around the first axis Y and can perform optical scanning at a predetermined first deflection angle at a predetermined first frequency Fy.

[0116] Next, the case of the second piezoelectric actuators 51 and 52 that cause the first support 4 to swing about the second axis X relative to the second support 6 will be described.

[0117] In this case, the optical deflector 1 applies a driving voltage to the second piezoelectric actuators 51 and 52. More specifically, in one of the second piezoelectric actuators 51, a third driving voltage Vx1 is applied between an odd-numbered second upper electrode pad 61c and a lower electrode pad 61a to drive the odd-numbered second piezoelectric cantilever 51A and 51C on one side. Furthermore, in one of the second piezoelectric actuators 51, a fourth driving voltage Vx2 is applied between an even-numbered second upper electrode pad 61d and a lower electrode pad 61a to drive the even-numbered second piezoelectric cantilever 51B and 51D on one side.

[0118] Furthermore, in another second piezoelectric actuator 52, a third driving voltage Vx1 is applied between another odd-numbered second upper electrode pad 62c and another lower electrode pad 62a to drive the other odd-numbered second piezoelectric cantilever 52A and 52C. Additionally, in another second piezoelectric actuator 52, a fourth driving voltage Vx2 is applied between another even-numbered second upper electrode pad 62d and another lower electrode pad 62a to drive the other even-numbered second piezoelectric cantilever 52B and 52D.

[0119] The third driving voltage Vx1 and the fourth driving voltage Vx2 are AC voltages with opposite phases (e.g., sine waves or sawtooth waves). Figure 4 Examples of the third drive voltage Vx1 and the fourth drive voltage Vx2 are shown. Figure 4 In the diagram, the sawtooth wave, shown by the solid line, indicates an example of the third drive voltage Vx1. In the following text, the third drive voltage Vx1 is also referred to as the first drive signal P. Furthermore, in... Figure 4 In the diagram, the sawtooth wave, indicated by alternating long and short dashed lines, represents an example of the fourth driving voltage Vx2. Hereinafter, the fourth driving voltage Vx2 is also referred to as the second driving signal N. Note that the third driving voltage Vx1 and the fourth driving voltage Vx2 can be alternating current voltages (e.g., sine waves or sawtooth waves) with their phases offset from each other. The viewing angle and deflection direction of the image projected by the optical deflector driving system 10 can be changed by altering the amplitude and offset of at least one of the two driving signals (the first driving signal P and the second driving signal N). This allows control over the swing angle and the offset angle.

[0120] At this time, the swing voltage components of the third driving voltage Vx1 and the fourth driving voltage Vx2 are set such that in the vertical direction of the second piezoelectric actuators 51 and 52 ( Figure 1 In the upward direction U and the opposite downward direction, the angular displacements of the odd-numbered second piezoelectric cantilever 51A, 51C, 52A and 52C and the angular displacements of the even-numbered second piezoelectric cantilever 51B, 51D, 52B and 52D are generated in opposite directions.

[0121] For example, in order to make the front ends of the second piezoelectric actuators 51 and 52 swing in the upward direction when the first support 4 swings about the second axis X ( Figure 1The odd-numbered second piezoelectric cantilever arms 51A, 51C, 52A, and 52C are shifted upwards, and the even-numbered second piezoelectric cantilever arms 51B, 51D, 52B, and 52D are shifted downwards. To shift the front ends of the second piezoelectric actuators 51 and 52 downwards, the odd-numbered second piezoelectric cantilever arms 51A, 51C, 52A, and 52C are shifted downwards, and the even-numbered second piezoelectric cantilever arms 51B, 51D, 52B, and 52D are shifted upwards.

[0122] As a result, the odd-numbered second piezoelectric cantilever arms 51A, 51C, 52A and 52C and the even-numbered second piezoelectric cantilever arms 51B, 51D, 52B and 52D bend and deform in opposite directions.

[0123] Figure 5A and Figure 5B This is a diagram showing the operation of a second piezoelectric actuator 51 of the optical deflector 1. Figure 5A The diagram shows a state where one of the second piezoelectric actuators 51 is not operating, and Figure 5B The state of operation of one of the second piezoelectric actuators 51 is shown.

[0124] like Figure 5B As shown, in the second piezoelectric cantilever 51D (4-1), a downward angular displacement is generated at the front end with the base end connected to the second support 6 as the fulcrum. In the second piezoelectric cantilever 51C (3-1), an upward angular displacement is generated at the front end with the base end connected to the front end of the second piezoelectric cantilever 51D (4-1) as the fulcrum.

[0125] In the second piezoelectric cantilever 51B (2-1), a downward angular displacement is generated at the front end, with the base end connected to the front end of the second piezoelectric cantilever 51C (3-1) as the fulcrum. In the second piezoelectric cantilever 51A (1-1), an upward angular displacement is generated at the front end, with the base end connected to the front end of the second piezoelectric cantilever 51B (2-1) as the fulcrum. As a result, in a second piezoelectric actuator 51, an angular displacement of a magnitude obtained by adding the bending deformation of one side of the second piezoelectric cantilever 51A to 51D is generated.

[0126] As a result, the first support portion 4 can swing around the second axis X, and optical scanning at a predetermined second deflection angle can be performed at a predetermined second frequency Fx. At this time, in these second piezoelectric actuators 51 and 52, an AC voltage with a frequency close to the mechanical resonant frequency of the first support portion 4 including the second piezoelectric actuators 51 and 52 is applied as a driving voltage to induce resonant driving, which allows optical scanning to be performed at a larger deflection angle.

[0127] Furthermore, when the first support 4 swings about the second axis X, it is not necessary to apply an AC voltage as described above, and a DC voltage can be applied instead. In this case, the magnitude of the bending deformation generated in the second piezoelectric cantilever 51A to 51D and 52A to 52D varies linearly based on the magnitude of the DC voltage. Therefore, for example, unlike the case where an AC voltage is applied to perform resonant drive of the piezoelectric cantilever, optional outputs can be obtained from the second piezoelectric actuators 51 and 52 by controlling the magnitude of the DC voltage.

[0128] As described above, when the first support 4 swings around the second axis X, the optical deflector 1 can linearly control the deflection angle based on the magnitude of the DC voltage applied as the driving voltage. This allows for the acquisition of a selectable deflection angle at a selectable speed.

[0129] Furthermore, each of the second piezoelectric actuators 51 and 52 is formed in a zigzag shape (or a bellows shape). Therefore, the bending deformation of each piezoelectric cantilever is accumulated. Thus, compared to the first piezoelectric actuators 31 and 32, the second piezoelectric actuators 51 and 52 readily achieve a large deflection angle.

[0130] Therefore, in this embodiment, when the first piezoelectric actuators 31 and 32 cause the mirror part 2 to swing, the frequency (i.e., the first frequency Fy) at which the displacement of the first piezoelectric actuators 31 and 32 changes in the upward or downward direction is set to a resonant frequency determined based on the structure, material, etc. of the optical deflector 1 (especially the piezoelectric cantilever, etc.) in order to obtain the largest possible deflection angle.

[0131] Furthermore, the second piezoelectric actuators 51 and 52 are each formed in a zigzag shape (or a bellows shape), and compared to the first piezoelectric actuators 31 and 32, they more easily cause the first support portion 4 to swing. Therefore, the second frequency Fx is set sufficiently lower than the first frequency Fy. In this embodiment, for example, the first frequency Fy is set to 30 kHz, and the second frequency Fx is set to 60 Hz.

[0132] Figure 6 This is a diagram showing the state in which an image P is drawn on a screen member 20 using a laser beam Ray scanned by an optical deflector 1 (raster scan) (illustrations of the condenser lens 14, the correction mirror 18, and the projection lens 23 are omitted).

[0133] As described above, when the mirror portion 2 swings relative to the first support portion 4 about the first axis Y, such as Figure 6 As shown, scanning is performed in a first direction (e.g., horizontal direction) using a laser beam Ray that enters the mirror section 2 from the light source 12.

[0134] Furthermore, when the mirror portion 2 swings relative to the second support portion 6 around the second axis X, as... Figure 6 As shown, scanning is performed in the second direction (e.g., the vertical direction) using a laser beam Ray that enters the mirror section 2 from the light source 12.

[0135] Figure 7 This shows the driving voltage applied to optical deflector 1 (see [reference]). Figure 7 (a) and the swing angle of mirror part 2 (see Figure 7 A diagram showing the relationship between (b) and (c).

[0136] In the optical deflector 1, when the displacements of the alternately arranged cantilever arms (odd-numbered second piezoelectric cantilever arms 51A, 51C, 52A and 52C and even-numbered second piezoelectric cantilever arms 51B, 51D, 52B and 52D) are the same, that is, when the voltage of the first drive signal P and the voltage of the second drive signal N are the same, the mirror part 2 is located at the reference position (= zero degree angle, see Figure 7 At (b)). The movement (oscillation) of the mirror part 2 around the second axis X is the same movement as the movement of the difference signal (the signal obtained by subtracting the second drive signal N from the first drive signal P) of the two drive signals. In other words, when the voltage of the difference signal is 0 V, the mirror part 2 is located at the reference position (= zero degree angle, see [reference]). Figure 7 (b) of the place.

[0137] As described above, an image P is drawn on the screen component 20 by a laser beam Ray scanned by an optical deflector 1.

[0138] At this time, the vertical width of the image P drawn on the screen component 20 by the laser beam Ray scanned by the optical deflector 1 (see...) Figure 8 (See attached figures H1 to H3) can be modified by changing the amplitude of at least one of the first driving signal P and the second driving signal N (see attached figures H1 to H3). Figure 4 And such Figure 8 The location shown has changed. Figure 8 Examples of images P with different vertical widths drawn on screen component 20 are shown.

[0139] Furthermore, the vertical position (offset) of the image P drawn on the screen member 20 by the laser beam Ray scanned by the optical deflector 1 can be changed by altering the offset (offset) of at least one of the first drive signal P and the second drive signal N (see [reference]). Figure 4 And such Figure 9 The location shown has changed. Figure 9 An example of an image P drawn on screen component 20 with different positions (offsets) in the vertical direction is shown.

[0140] Next, a functional configuration example of the optical deflector drive system 10 will be described.

[0141] Figure 10 An example of a functional configuration of the optical deflector drive system 10 is shown.

[0142] like Figure 10 As shown, the optical deflector driving system 10 includes an image signal input unit 102, an image signal processing unit 116, an image signal accumulation unit 104, a MEMS driving unit 108, a sensor signal input unit 110, and a light source driving unit 114.

[0143] Image signals output from an external device (not shown) connected to the image signal input unit 102 are input to the image signal input unit 102.

[0144] The image signal (image) input to the image signal input unit 102 is accumulated in the image signal accumulation unit 104.

[0145] The image signal processing unit 116 is, for example, a CPU (central processing unit) or a DSP (digital signal processor), and generates drive signals for driving the optical deflectors 1 (first piezoelectric actuators 31 and 32 and second piezoelectric actuators 51 and 52) and the light source 12, so as to draw an image on the screen member 20 based on the image signal (image) accumulated in the image signal accumulation unit 104.

[0146] At this time, for example, the image signal processing unit 116 adjusts the drive signal of the optical deflector 1 so that the sensor signal input to the sensor signal input unit 110 (e.g., the voltage detected by the first detection units 71y and 72y and the second detection units 71x and 72x) is consistent with the target value (feedback control).

[0147] The MEMS driving unit 108 performs D / A conversion (further amplification) on the driving signal generated by the image signal processing unit 116 that drives the first piezoelectric actuator, and applies the obtained driving signal to the optical deflectors 1 (first piezoelectric actuators 31 and 32) as a first driving voltage Vy1 and a second driving voltage Vy2. Furthermore, the MEMS driving unit 108 performs D / A conversion (further amplification) on the driving signal generated by the image signal processing unit 116 that drives the second piezoelectric actuator, and applies the obtained driving signal to the optical deflectors 1 (second piezoelectric actuators 51 and 52) as a third driving voltage Vx1 (first driving signal P) and a fourth driving voltage Vx2 (second driving signal N).

[0148] The light source driving unit 114 performs D / A conversion (further amplification) on the driving signal of the driving light source generated by the image signal processing unit 116, and applies the obtained driving signal to the light source 12.

[0149] Next, a functional configuration example of the image signal processing unit 116 will be described.

[0150] Figure 11 An example of the functional configuration of the image signal processing unit 116 is shown.

[0151] like Figure 11 As shown, the image signal processing unit 116 includes a waveform generation unit 81, a calculation unit 82, a timing determination unit 83, an amplitude control unit 84, an offset division unit 85, an offset level control unit 86, a first addition unit 87, and a second addition unit 88. These units are implemented by the image signal processing unit 116 (CPU or DSP) executing a predetermined program. Note that some or all of the units can be implemented in hardware.

[0152] Waveform generation unit 81 outputs waveform data. Figure 13 of (a) Figure 18 of (h) Figure 20 (a) and Figure 21 Each of the (h) examples shows waveform data. The waveform data is, for example, a 60 Hz sawtooth wave. The waveform data is pre-stored in a storage unit (not shown) such as a memory.

[0153] The calculation unit 82 outputs amplitude data, time data, and offset level data. Figure 13 (b) and Figure 20 (b) shows examples of amplitude data. Amplitude data indicates the amplitude of the driving signal.

[0154] The time data includes time data indicating the time of rise (rise time) and time data indicating the time of fall (fall time). Figure 18 (b) and Figure 21 (b) shows examples of time data (rise time), and Figure 18 (c) and Figure 21 (c) each shows examples of time data (descent time). More specifically, in Figure 18 of (h) and Figure 21 In (h), the time data (rise time) indicates time t2, and... Figure 18 of (h) and Figure 21 In (h), the time data (fall time) indicates time t1. Figure 18 (a) and Figure 21 (a) shows an example of offset level data. Offset level data indicates the offset amount.

[0155] The timing determination unit 83 determines the timing when the voltage of the drive signal to be changed becomes the minimum. Furthermore, the timing determination unit 83 outputs a first signal P (see...). Figure 13 (c) and the first signal N (see Figure 13 (d)). The first signal P indicates the same amplitude as indicated by the amplitude data. Similarly, the first signal N indicates the same amplitude as indicated by the amplitude data. In addition, the timing determination unit 83 outputs a fourth signal P (see Figure 21 (f) and the fourth signal N (see Figure 18 (g)). The fourth signal P is a continuous pulse that rises at each offset / t2. Similarly, the fourth signal N is a continuous pulse that rises at each offset / t1.

[0156] Amplitude control unit 84 generates a second signal P (see Figure 13 (e) and the second signal N (see Figure 13 (f)), and outputs the generated second signal P and the generated second signal N. By measuring the amplitude of the waveform data (see Figure 13 The second signal P is generated by adjusting (a) to the same amplitude as indicated by the first signal P. Similarly, the second signal P is generated by adjusting the phase of the waveform data (see [reference]). Figure 13 The amplitude of the waveform data obtained by inverting (a) (by 180 degrees) to the same amplitude as the amplitude indicated by the first signal N is adjusted to generate the second signal N.

[0157] The offset division unit 85 divides the offset amount indicated by the offset level data output from the calculation unit 82 by the rise time t2 or the fall time t1. The offset division unit 85 outputs a third signal P (see...). Figure 21 (d) and the third signal N (see Figure 18 (e)). The third signal P indicates the offset amount indicated by the offset level data / rise time t2. The third signal N indicates the offset amount indicated by the offset level data / fall time t1.

[0158] (For example, in reflecting) Figure 18 In the case of the offset shown in (j), each time the divided time (e.g., offset offset / fall time t1) elapses, the offset level control unit 86 counts the value indicated by the fifth signal N output by the offset level control unit 86 in ascending order by a predetermined amount (e.g., 1). Note that in some cases (e.g., in reflecting...) Figure 21 In the case of the offset shown in (j), whenever the divided time (e.g., offset offset / rise time t2) has elapsed, the offset level control unit 86 will count the value indicated by the fifth signal N output from the offset level control unit 86 in descending order by a predetermined amount (e.g., 1).

[0159] The first adding unit 87 outputs the input second signal P unchanged as the first driving signal P. When the fifth signal P is input to the first adding unit 87, the first adding unit 87 adds the fifth signal P (reflecting the change) to the second signal P, and outputs the added (reflecting the change) second signal P as the first driving signal P.

[0160] The second adding unit 88 outputs the input second signal N unchanged as the second drive signal N. When the fifth signal N is input to the second adding unit 88, the second adding unit 88 adds the fifth signal N (reflecting the change) to the second signal N, and outputs the added (reflecting the change) second signal N as the second drive signal N.

[0161] Next, the process of causing the mirror section 2 to swing around the second axis X by the MEMS drive unit 108 will be described.

[0162] Figure 12 This is a sequence diagram of the process by which the mirror part 2 swings around the second axis X by the MEMS drive unit 108. Figure 13 An example of the signal (time plot) is shown when the vertical width of image P decreases.

[0163] First, describe when Figure 8 When the image P with a vertical width H1 shown in (a) is drawn, the mirror part 2 is oscillated around the second axis X by the MEMS drive unit 108.

[0164] In the following text, we assume that... Figure 12 As shown, the waveform data output from waveform generation unit 81 (see...) Figure 13 (a) is input to the timing determination unit 83 and the amplitude control unit 84 (steps S1 and S2). Furthermore, it is assumed that amplitude data indicating the amplitude h1 output from the calculation unit 82 (see...) Figure 13 (b) is input to the timing determination unit 83 (step S3).

[0165] First, when the amplitude data indicating amplitude h1 is input to the timing determination unit 83 (step S3), the timing determination unit 83 outputs a first signal P indicating the same amplitude h1 as indicated by the amplitude data (see...). Figure 13 (c) and the first signal N (see Figure 13 (d) (step S4). The first signal P and the first signal N output from the timing determination unit 83 are input to the amplitude control unit 84 (step S4).

[0166] Next, when the first signal P and the first signal N are input to the amplitude control unit 84 (step S4), the amplitude control unit 84 generates the second signal P (see...). Figure 13 (e) and the second signal N (see Figure 13 (f) (step S5), and output the generated second signal P and the generated second signal N (steps S6 and S7). By measuring the amplitude of the waveform data (see... Figure 13 The second signal P is generated by adjusting (a) to the same amplitude h1 indicated by the first signal P. Similarly, the second signal P is generated by adjusting the phase of the waveform data (see [reference]). Figure 13 The amplitude of the waveform data obtained by inverting (a) (by 180 degrees) to the same amplitude h1 indicated by the first signal N is adjusted to generate the second signal N. The second signal P output from the amplitude control unit 84 is input to the first addition unit 87 (step S6). On the other hand, the second signal N output from the amplitude control unit 84 is input to the second addition unit 88 (step S7).

[0167] When the second signal P is input to the first adding unit 87 (step S6), the first adding unit 87 outputs the second signal P unchanged (step S8). The second signal P output from the first adding unit 87 is input to the MEMS driving unit 108 (step S8).

[0168] On the other hand, when the second signal N is input to the second addition unit 88 (step S7), the second addition unit 88 outputs the second signal N unchanged (step S9). The second signal N output from the second addition unit 88 is input to the MEMS driving unit 108 (step S9).

[0169] When a second signal P with amplitude h1 is input to the MEMS driving unit 108 (step S8), the MEMS driving unit 108 performs D / A conversion (further amplification) on the second signal P with amplitude h1, and applies the obtained signal to the optical deflector 1 as a third driving voltage Vx1 (first driving signal P) (step S11). Furthermore, when a second signal N with amplitude h1 is input to the MEMS driving unit (step S9), the MEMS driving unit performs D / A conversion (further amplification) on the second signal N with amplitude h1, and applies the obtained signal to the optical deflector 1 as a fourth driving voltage Vx2 (second driving signal N) (step S12).

[0170] Therefore, mirror 2 oscillates around the second axis X within a range corresponding to the amplitude h1 indicated by the amplitude data. As a result, Figure 8 Image P with a vertical width H1, as shown in (a), is drawn.

[0171] Next, the problems discovered by the inventors will be described.

[0172] Figure 14 and Figure 15 It is a diagram used to explain the problem discovered by the inventor.

[0173] For example, by changing the amplitude of the driving signal (e.g., the second signal P and the second signal N), such as Figure 8 As shown, the vertical width of the image drawn on the screen component 20 can be changed. Furthermore, for example, by adding a fifth signal P (and a fifth signal N) to the second signal P (and the second signal N) or subtracting the fifth signal P (and the fifth signal N) from the second signal P (and the second signal N), such as... Figure 9 As shown, the offset of the image drawn on the screen component 20 can be changed.

[0174] The optical deflector 1 includes multiple inherent oscillation modes. When a signal including frequency components close to the inherent oscillation frequency is applied to the optical deflector 1, resonance occurs. The resonance phenomenon generates a large displacement of the optical deflector 1 (mirror section 2) using a small applied voltage. Therefore, the driving signal (driving voltage) applied to the optical deflector 1 needs to be a signal that will not cause runaway resonance (abnormal oscillation).

[0175] However, as a result of their research, the inventors discovered a problem: when the timing of the input command for changing the offset (or amplitude) reflects the change in offset (or amplitude), the waveform of the drive signal (drive voltage) is disturbed before and after the change (see [reference]). Figure 14 Abnormal oscillations occur in optical deflector 1 due to unwanted frequency components (unintentional frequency components) included in the edges of the drive signal (drive voltage) with a disturbed waveform. This causes a striped pattern to appear in the image P drawn by the light scanned by optical deflector 1 (see [link]). Figure 15 ).

[0176] Next, the process of changing the vertical width of the image drawn on the screen member 20 while preventing abnormal oscillations in the optical deflector 1 will be described.

[0177] Figure 16 This is a sequence diagram of the process of changing the vertical width of the image drawn on the screen component 20 while preventing abnormal oscillations in the optical deflector 1.

[0178] In the following text, the process of changing the vertical width of the image drawn on the screen component 20 will be described. Figure 8 The vertical width H1 of image P shown in (a) is changed (reduced) to Figure 8 The processing of the vertical width H2 of image P shown in (b).

[0179] In the following text, it is assumed that... Figure 8 Image P with a vertical width H1, shown in (a), has been processed by... Figure 12 The processes shown in steps S1 to S12 are drawn on screen component 20.

[0180] First, when the amplitude data of the indicated amplitude h2 is different from the amplitude data of the currently input indicated amplitude h1, Figure 13 When (b) is input to the timing determination unit 83 (step S20), the timing determination unit 83 determines when the voltage of the second signal P (see...) Figure 13 Whether the timer for (e) to become the minimum has arrived (step S21). For example, by a user's predetermined operation, amplitude data of an indication amplitude h2 that is different from the currently input indication amplitude h1 is input. The amplitude data of the indication amplitude h2 that is different from the currently input indication amplitude h1 is an example of an instruction for changing amplitude according to the present invention.

[0181] The timing determination unit 83 waits until the timing occurs when the voltage of the second signal P becomes the minimum (see [reference]). Figure 13 (Referring to reference numeral P1 in (e)) (Step S21: No). This timing coincides with the timing when the voltage of the waveform data becomes minimum. Therefore, this timing can be determined from the waveform data.

[0182] When the timing determination unit 83 determines that the timing occurs when the voltage of the second signal P becomes the minimum (see...), Figure 13 (See reference numeral P1 in (e)) (step S21: Yes), the timing determination unit 83 outputs a first signal P indicating the same amplitude as the amplitude h2 indicated by the amplitude data (see) Figure 13 (c) (step S22). The first signal P output from the timing determination unit 83 is input to the amplitude control unit 84 (step S22).

[0183] In addition, the timing determination unit 83 determines the voltage of the second signal N (see Figure 13 The timing determination unit 83 waits until the voltage of the second signal N (see step S23) reaches its minimum value. Figure 13 (f) until the timer for the minimum value of (f) arrives (see below) Figure 13 (Ref. P2 in (f)) (Step S23: No). The second signal N has a waveform that is opposite in phase to the waveform data. Therefore, this timing is consistent with the timing when the voltage of the waveform data becomes maximum, and can be determined from the waveform data.

[0184] When the timing determination unit 83 determines that the timing occurs when the voltage of the second signal N becomes the minimum (see...), Figure 13 (f) Reference numeral P2 (step S23: Yes), timing determination unit 83 outputs a first signal N indicating the same amplitude as the amplitude h2 indicated by the amplitude data (see Figure 1). Figure 13 (d) (step S24). The first signal N output from the timing determination unit 83 is input to the amplitude control unit 84.

[0185] Next, when the first signal P is input to the amplitude control unit 84 (step S22), the amplitude control unit 84 generates a second signal P with an amplitude h2 (see...). Figure 13 (e) (step S25), and output the resulting second signal P with amplitude h2 (step S26). By measuring the amplitude of the waveform data (see... Figure 13 (a) is adjusted to the same amplitude h2 as indicated by the first signal P to generate a second signal P with amplitude h2. Step S25 corresponds to an example of a change response unit according to the invention. The second signal P output from the amplitude control unit 84 is input to the first addition unit 87 (step S26).

[0186] Furthermore, when the first signal N is input to the amplitude control unit 84 (step S24), the amplitude control unit 84 generates a second signal N with an amplitude h2 (see [link to relevant documentation]). Figure 13 (f) (step S27), and output the generated second signal N with amplitude h2 (step S28). By adjusting the phase of the waveform data (see Figure 13 The amplitude of the waveform data obtained by inverting (a) (by 180 degrees) to the same amplitude h2 indicated by the first signal N is adjusted to generate a second signal N with amplitude h2. Step S27 corresponds to an example of the change response unit according to the invention. The second signal N with amplitude h2 output from the amplitude control unit 84 is input to the second addition unit 88 (step S28).

[0187] When the second signal P is input to the first adding unit 87 (step S26), the first adding unit 87 outputs the second signal P unchanged (step S29). The second signal P output from the first adding unit 87 is input to the MEMS driving unit 108 (step S29).

[0188] On the other hand, when the second signal N is input to the second addition unit 88 (step S28), the second addition unit 88 outputs the second signal N unchanged (step S30). The second signal N output from the second addition unit 88 is input to the MEMS driving unit 108 (step S30).

[0189] When a second signal P with amplitude h2 is input to the MEMS driving unit 108 (step S29), the MEMS driving unit 108 performs D / A conversion (further amplification) on the second signal P with amplitude h2, and applies the obtained signal to the optical deflector 1 as a third driving voltage Vx1 (first driving signal P) (step S31). Furthermore, when a second signal N with amplitude h2 is input to the MEMS driving unit (step S30), the MEMS driving unit performs D / A conversion (further amplification) on the second signal N with amplitude h2, and applies the obtained signal to the optical deflector 1 as a fourth driving voltage Vx2 (second driving signal N) (step S32).

[0190] Therefore, mirror 2 oscillates around the second axis X within a range corresponding to the amplitude h2 indicated by the amplitude data. As a result, it has... Figure 8 The image P with a vertical width H2 shown in (b) is drawn.

[0191] As described above, the amplitude change is not reflected at the timing when the command for changing the amplitude is input (step S20). Instead, when the timing is reached when it is determined that the voltage of the drive signal to be changed has become the minimum (step S21: Yes, or step S23: Yes), the amplitude change is reflected in the drive signal to be changed (second signal P or second signal N) (step S25 or S27). During the period from the timing when the command for changing the amplitude is input until the timing when the voltage of the drive signal to be changed (second signal P or second signal N) becomes the minimum, the drive is performed while maintaining the swing width before the change.

[0192] As a result, even in cases that reflect changes in amplitude, abnormal oscillations in optical deflector 1 can be prevented (thus preventing striped patterns from appearing in the image drawn by the light scanned by the optical deflector).

[0193] The above describes the use of Figure 13 The signal shown will Figure 8 The vertical width H1 of image P shown in (a) is changed (reduced) to Figure 8 The processing of the vertical width H2 of image P shown in (b); however, the processing is not limited to this. For example, by using Figure 20 The signal shown Figure 8 The vertical width H1 of image P shown in (a) can be changed (increased) to Figure 8 The vertical width H3 of image P shown in (c) is . Figure 20 An example of the signal (time plot) is shown when the vertical width of image P increases.

[0194] Next, the process of changing the offset of the image drawn on the screen member 20 while preventing abnormal oscillations in the optical deflector 1 will be described.

[0195] Figure 17 This is a sequence diagram of the process of changing the offset of the image drawn on the screen component 20 while preventing abnormal oscillations in the optical deflector 1. Figure 18 An example of the signal (time plot) is shown when image P is shifted upwards.

[0196] In the following text, the process of changing the offset of the image drawn on the screen component 20 is described as follows: Figure 9 The upward offset shown in (b) Figure 9 The processing of image P shown in (a).

[0197] In the following text, it is assumed that... Figure 9 Image P shown in (a) has been executed Figure 17 The processes in steps S1 to S12 shown are drawn on screen component 20. Note that... Figure 17 Steps S1 to S12 shown are similar to Figure 12 Steps S1 to S12 are shown.

[0198] When the offset data of the indicator offset differs from the offset data of the currently input indicator offset (see...), the offset level data of the indicator offset is different. Figure 18 (a) and time data (see Figure 18 (b) and Figure 18 When (c) is input to the offset partitioning unit 85 (step S40), the offset partitioning unit 85 outputs the third signal N (see Figure 18 (e) (step S41). For example, by a predetermined operation by the user, offset level data of the indicated offset amount that is different from the offset data of the currently input indicated offset amount is input. The offset level data of the indicated offset amount that is different from the offset data of the currently input indicated offset amount is an example of an instruction for changing the offset according to the present invention. The third signal N indicates the offset amount offset indicated by the offset level data / fall time t1. The third signal N output from the offset division unit 85 is input to the timing determination unit 83 (step S41).

[0199] When the third signal N is input to the timing determination unit 83, the timing determination unit 83 determines the voltage of the second signal N (see...). Figure 18 The timing determination unit 83 waits until the timing when the voltage of the second signal N becomes the minimum arrives (step S42). The timing determination unit 83 waits until the timing when the voltage of the second signal N becomes the minimum arrives (see [link]). Figure 18 (l) reference numeral P3 (step S42: no).

[0200] When the timing determination unit 83 determines that the timing occurs when the voltage of the second signal N becomes the minimum (see...), Figure 18 (See attached figure P3 in (l)) (step S42: Yes), the timing determination unit 83 outputs the fourth signal N (see Figure 18 (g) (step S43). The fourth signal N is a continuous pulse that rises at each offset offset / fall time t1. The fourth signal N output from the timing determination unit 83 is input to the offset level control unit 86.

[0201] Whenever the divided time (offset offset / fall time t1) elapses (step S44: yes), that is, at the fourth signal N (see Figure 18 At each rising timing of (g), the offset level control unit 86 counts the value indicated by the fifth signal N output from the offset level control unit 86 in ascending order by a predetermined amount (e.g., 1) (step S45).

[0202] The offset level control unit 86 repeats the processing in steps S44 to S46 (step S47: No) until the counted value reaches the offset amount (step S47: Yes). The result is as follows: Figure 19 As shown, each time the divided time (offset offset / fall time t1) elapses, the fifth signal N becomes a step signal that is counted in ascending order according to a predetermined amount. The fifth signal N output from the offset level control unit 86 is input to the second addition unit 88.

[0203] When the fifth signal N is input to the second adding unit 88 (step S46), the second adding unit 88 adds the (reflecting the change) fifth signal N to the second signal N (step S48), and outputs the added (reflecting the change) second signal N as the second drive signal N (step S9). At this time, since the fifth signal N input to the second adding unit 88 is a step signal that is counted in ascending order by a predetermined amount every time the divided time (offset offset / fall time t1) elapses (see...), Figure 19 Therefore, the change is reflected (gradually) in the drive signal to be changed (second signal N) in a step manner. Step S48 corresponds to an example of the change reflection unit according to the present invention. The second signal N output from the second addition unit 88 is input to the MEMS drive unit 108 (step S9).

[0204] When the second signal N reflecting the change is input to the MEMS driving unit 108 (step S9), the MEMS driving unit 108 performs D / A conversion (further amplification) on the second signal N reflecting the change, and applies the obtained signal to the optical deflector 1 as the fourth driving voltage Vx2 (second driving signal N) (step S12). Furthermore, when the second signal P is input to the MEMS driving unit 108 (step S8), the MEMS driving unit 108 performs D / A conversion (further amplification) on the second signal P, and applies the obtained signal to the optical deflector 1 as the third driving voltage Vx1 (first driving signal P) (step S11).

[0205] result, Figure 9 Image P shown in (a) can be as follows Figure 9 As shown in (b), it shifts upwards.

[0206] As described above, the offset change is not reflected at the timing when the instruction for changing the offset is input (step S40), but when the timing arrives to determine that the voltage of the drive signal to be changed has become the smallest (step S42: yes), the offset change is reflected in the drive signal to be changed (e.g., the second signal N) in a step manner (steps S43 to S47).

[0207] As a result, even in the case of changes in offset, abnormal oscillations in optical deflector 1 can be prevented (thus preventing striped patterns from appearing in the image drawn by the light scanned by the optical deflector).

[0208] The above describes the use of Figure 18 The signal shown will Figure 9 Image P shown in (a) is as follows Figure 9 The upward offset process shown in (b) is used; however, the process is not limited to this. For example, by using Figure 21 The signal shown is in Figure 9 Image P shown in (a) can be as follows Figure 9 As shown in (c), it shifts downwards. Figure 21 An example of the signal (time plot) is shown when image P is shifted downwards.

[0209] As described above, according to this embodiment, even in the case of changes in offset (or amplitude), abnormal oscillations in the optical deflector 1 can be prevented (thereby preventing striped patterns from appearing in the image drawn by the light scanned by the optical deflector).

[0210] This is because the change in offset (or amplitude) is not reflected at the timing when the command for changing the offset (or amplitude) is input. Instead, the change in offset (or amplitude) is reflected in the drive signal to be changed when the timing arrives at the time when the voltage of the drive signal to be changed becomes the minimum. This allows the removal of unwanted frequency components (unintentional frequency components) that cause abnormal oscillations in the optical deflector 1.

[0211] Next, we will describe the variant example.

[0212] Figure 22 This is a diagram illustrating a variation of the fifth signal.

[0213] In the above embodiment, an example of performing the processing (processing reflecting the change in offset) in steps S44 to S47 during a time period is described; however, the processing is not limited to this. For example, such as Figure 22 As shown, the processing in steps S44 to S47 (processing that reflects the change in offset) can be performed during multiple time periods.

[0214] The values ​​described in the above embodiments are illustrative, and of course, appropriate values ​​different from those described above can also be used.

[0215] The above embodiments are merely illustrative in each respect. The invention is not to be limited by the description of the above embodiments. The invention can be implemented in various other forms without departing from the spirit or key features.

[0216] This application is based on and claims the benefit of priority to Japanese Patent Application No. 2021-083666, filed on May 18, 2021, the entire contents of which are incorporated herein by reference.

[0217] List of reference numerals

[0218] 1: Optical deflector; 2: Mirror section; 2a: Reflective surface; 2b: Reflective surface support; 4: First support; 6: Second support; 10: Optical deflector drive system; 12: Light source; 14: Condenser lens; 18: Correction mirror; 20: Screen component; 21, 22: Torsion bars; 23: Projection lens; 31: First piezoelectric actuator; 31A: First piezoelectric cantilever; 32: First piezoelectric actuator; 32A: First piezoelectric cantilever; 51: Second piezoelectric actuator; 51A: ... Two piezoelectric cantilever arms, 51B: second piezoelectric cantilever arm, 51C: second piezoelectric cantilever arm, 51D: second piezoelectric cantilever arm, 52: second piezoelectric actuator, 52A: second piezoelectric cantilever arm, 52B: second piezoelectric cantilever arm, 52C: second piezoelectric cantilever arm, 52D: second piezoelectric cantilever arm, 61a: lower electrode pad, 61b: first upper electrode pad, 61c: second upper electrode pad for odd-numbered applications, 61d: second upper electrode pad for even-numbered applications, 61e: first detection electrode pad, 62a: Lower electrode pad, 62b: First upper electrode pad, 62c: Second upper electrode pad for odd-numbered applications, 62d: Second upper electrode pad for even-numbered applications, 62e: Second detection electrode pad, 71x: Second detection unit, 71y: First detection unit, 72x: Second detection unit, 72y: First detection unit, 81: Waveform generation unit, 82: Calculation unit, 83: Timing determination unit, 84: Amplitude control unit, 85: Offset division unit, 86: Offset level control Units: 87: First Addition Unit; 88: Second Addition Unit; 102: Image Signal Input Unit; 104: Image Signal Accumulation Unit; 108: MEMS Driving Unit; 110: Sensor Signal Input Unit; 114: Light Source Driving Unit; 116: Image Signal Processing Unit; B: Support; Fx: Second Frequency; Fy: First Frequency; H1 to H3: Vertical Width; L1: Lower Electrode; L2: Piezoelectric Body; L3: Upper Electrode; M1: Interlayer Insulating Film; M2: Passivation Film

Claims

1. An optical deflector driving system, the optical deflector driving system comprising: The system comprises a mirror portion, a first support portion configured to support the mirror portion, a second support portion configured to support the first support portion, and at least one actuator configured to oscillate the first support portion relative to the second support portion about a swing axis. The actuator includes a plurality of piezoelectric cantilever arms disposed in the direction of the swing axis. The plurality of piezoelectric cantilever arms are connected in a bellows shape such that each of the piezoelectric cantilever arms is folded back relative to its adjacent piezoelectric cantilever arm. The free end of the piezoelectric cantilever arm on the mirror portion side is connected to the first support portion, and the free end of the piezoelectric cantilever arm on the second support portion side is connected to the second support portion. An optical deflector driving system applies a first driving voltage corresponding to a first driving signal to an even-numbered piezoelectric cantilever arm counted from the mirror portion to bend and deform the even-numbered piezoelectric cantilever arm, and applies a second driving voltage corresponding to a second driving signal to an odd-numbered piezoelectric cantilever arm counted from the mirror portion to bend and deform the odd-numbered piezoelectric cantilever arm. The optical deflector driving system includes: A timing determination unit is configured to determine a timing point when the voltage of the drive signal to be changed (the first drive signal or the second drive signal) becomes the minimum, upon input of an instruction for changing at least one of the first drive signal and the second drive signal; and A change response unit is configured to reflect the change in the drive signal to be changed when the timing is determined to be when the voltage of the drive signal to be changed becomes the smallest.

2. The optical deflector driving system according to claim 1, wherein, The command is used to change the amplitude.

3. The optical deflector driving system according to claim 1, wherein, The instruction is used to change the offset.

4. The optical deflector driving system according to claim 1, wherein the optical deflector driving system further includes an offset division unit, wherein, The instruction is offset level data indicating the offset amount. The offset division unit divides the offset by the rise time or fall time, and The change response unit reflects the change in the drive signal to be changed in a step manner every time the divided time has elapsed.

5. An optical deflector driving method, the optical deflector driving method comprising the following steps: The change command input step inputs a command for changing at least one of a first drive signal corresponding to a first drive voltage and a second drive signal corresponding to a second drive voltage, wherein the first drive voltage and the second drive voltage are applied to an actuator that causes the mirror portion of the optical deflector to oscillate around a swing axis. The determination step, when the instruction is input, determines the timing when the voltage of the drive signal to be changed in the first drive signal and the second drive signal becomes the minimum. as well as The change response step, wherein when the timing is determined to be when the voltage of the drive signal to be changed becomes the minimum, the change is reflected on the drive signal to be changed.

6. The optical deflector driving method according to claim 5, wherein, The command is used to change the amplitude.

7. The optical deflector driving method according to claim 5, wherein, The instruction is used to change the offset.

8. The optical deflector driving method according to claim 5, further comprising an offset division step, wherein, The instruction is offset level data indicating the offset amount. In the offset division step, the offset is divided by the rise time or fall time, and In the change response step, the change is reflected in the drive signal to be changed in a step manner each time the allocated time has elapsed.

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