JP2019159162A - Optical scanner, image display device, and moving body - Google Patents

Abstract

To enable an increase in the peak value of current in wiring for applying a drive voltage to an optical deflector to be prevented.SOLUTION: An optical scanner in one embodiment of the present invention comprises an optical deflector and a control unit for controlling the drive of the optical deflector. The optical deflector includes a mirror unit having a mirror surface, a meander-shaped cantilever for rotatably supporting the mirror unit, a first and a second piezoelectric member for causing a warp deformation of the cantilever, and a common wiring connected to an electrode on one end side of the first and second piezoelectric members. The timing of the control unit at which a first drive voltage applied to the first piezoelectric member is changed and the timing at which a second drive voltage applied to the second piezoelectric member is changed are relatively shifted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical scanning device, an image display device, and a moving body.

  Conventionally, an optimum application method for a driving voltage for driving a MEMS (Micro Electro Mechanical Systems) mirror has been studied.

  For example, as a method for applying a drive voltage, there is a technique that discloses a technique for reversing the phase of a drive waveform of a voltage applied to each piezoelectric member of a MEMS mirror (see Patent Document 1).

  However, the conventional driving voltage application technique has a problem that the peak value of current increases in the wiring for applying the driving voltage to an optical deflector such as a MEMS mirror.

  The present invention has been made in view of the above, and provides an optical scanning device, an image display device, and a moving body that prevent an increase in current peak value in a wiring that applies a driving voltage to an optical deflector. With the goal.

  In order to solve the above-described problems and achieve the object, an optical scanning device according to an embodiment of the present invention includes an optical deflector and a control unit that controls driving of the optical deflector, and the optical deflector. The container includes a mirror portion having a mirror surface, a meander-shaped cantilever that rotatably supports the mirror portion, a first piezoelectric member and a second piezoelectric member that cause warpage deformation of the cantilever, and the first And a common wiring connected to an electrode on one end side of the second piezoelectric member, and the control unit changes a first drive voltage applied to the first piezoelectric member. And the timing of changing the second drive voltage to which the second piezoelectric member is applied are relatively shifted from each other.

  According to the present invention, there is an effect of preventing an increase in the peak value of the current in the wiring for applying the driving voltage to the optical deflector.

FIG. 1 is a diagram illustrating an example of an optical scanning device according to the first embodiment. FIG. 2 is a schematic top view of the optical deflector. FIG. 3 is an excerpt of the upper surface of the mirror frame member. 4 is a cross-sectional view taken along the line L-L ′ shown in FIG. 3. FIG. 5 is a cross-sectional view taken along the line M-M ′ shown in FIG. 3. 6 is a cross-sectional view taken along line N-N ′ shown in FIG. 3. FIG. 7 is a cross-sectional view of the optical deflector along X-X ′ (see FIG. 2). FIG. 8 is a schematic diagram of electrical wiring for displacing the cantilever group. FIG. 9 is a diagram showing an equivalent circuit of the piezoelectric member group provided with the electrical wiring shown in FIG. FIG. 10 is a detailed explanatory diagram of drive waveforms. FIG. 11 is a diagram for explaining that the peak current value varies depending on the region of the drive waveform. FIG. 12 is a diagram showing an equivalent circuit in which only one pair of cantilever groups is cut out. FIG. 13 is a diagram illustrating an example of a relationship between peak current values in each region (first region, second region, and third region) when two drive waveforms are formed at the same timing. FIG. 14 is a diagram illustrating an example of a relationship between peak current values in each region (first region, second region, and third region) when two drive waveforms are formed at different timings. FIG. 15 is a diagram illustrating a head-up display having an optical scanning device.

  Hereinafter, embodiments of an optical scanning device, an image display device, and a moving body will be described with reference to the accompanying drawings. In addition, this invention is not limited by the following embodiment.

(First embodiment)
FIG. 1 is a diagram illustrating an example of an optical scanning device according to the first embodiment. The optical scanning device 1 of FIG. 1 includes an optical deflector 100 and a drive control unit (corresponding to a “control unit”) 500. The optical deflector 100 rotates the mirror in response to a drive signal from the drive control unit 500. , Optical scanning.

  The optical deflector 11 only needs to include a configuration that performs optical scanning in one axis direction using a meander-shaped cantilever. Here, as an example, a configuration in which optical scanning is performed in the biaxial direction of the main scanning direction and the sub-scanning direction is shown, but the present invention is not limited to this. Although the configuration of the optical deflector 100 and the drive control unit 500 is mainly shown here, the optical scanning device 1 may include a light source that performs optical scanning, an optical system that guides light from the light source to a mirror, and the like. .

  The optical deflector 100 is a MEMS (Micro Electro Mechanical Systems) mirror. The drive control unit 500 is a control circuit that applies a drive voltage as a drive signal to the optical deflector 100. FIG. 1 shows a configuration of an FPGA (Field Programmable Gate Array) 510 and a driver 520 (D / A 521 and operational amplifier 522) as an example of a control circuit. The FPGA 510 outputs a drive voltage signal for rotating the mirror of the optical deflector 100 in the main scanning direction or the sub-scanning direction to the D / A 521. The D / A 521 converts the drive voltage signal from digital to analog and outputs the converted signal to the operational amplifier 522. The operational amplifier amplifies the analog drive voltage signal output from the D / A 521 with a predetermined gain and applies the amplified signal to the optical deflector 100.

  In the present embodiment, the optical deflector 100 has a piezoelectric member (a first piezoelectric member and a second piezoelectric member) different from a meander-shaped cantilever as an actuator for rotating a mirror. The piezoelectric member warps and deforms the cantilever by different deformations to rotate the mirror in one axial direction. The electrodes on one end side of the piezoelectric member are connected by common wiring. In the present embodiment, a description is given of a case where the timing for changing the first driving voltage applied to the first piezoelectric member or the timing for changing the second driving voltage applied to the second piezoelectric member are relatively shifted. To do. Here, as an example, when the drive control unit 500 changes the first drive voltage and the second drive voltage step by step in a predetermined time interval, the timing at which the first drive voltage is changed and the second drive voltage The peak value of the current flowing in the common wiring is reduced by relatively shifting the timing of changing the current. The relative shifting is performed by the D / A 521. The shift amount may be set in advance in D / A 521 or may be set from FPGA 510 to D / A 521.

  FIG. 2 is a schematic top view of the optical deflector 100. As shown in FIG. 2, the optical deflector 100 includes a mirror rotation in one axis direction (first axis) corresponding to the main scanning direction and another axis direction (second axis) corresponding to the sub scanning direction. A cantilever structure that enables rotation of the mirror is constructed. Specifically, the rotation of the mirror in the main scanning direction includes a substrate 101 (SOI substrate: Silicon On Insulator), a mirror unit 103 having a mirror surface, and a torsion bar (mirror support unit) 110 that supports the mirror unit 103. The cantilever 109 and the piezoelectric member 104 that generates warp deformation in the cantilever 109 are made possible. These are included in the mirror frame member 301 as “cantilever components”. The mirror frame member 301 is connected to one end of a meander-shaped cantilever (hereinafter referred to as a cantilever group) 302 composed of a plurality of beams. The other end of the meander-shaped cantilever group 302 is connected to the outer peripheral substrate 101. On the meander-shaped cantilever group 302, there is a piezoelectric member group 303 as means for generating warp deformation on a plurality of beams. Thus, the mirror frame member 301 is supported so as to be rotatable in the second axis direction.

  The mirror frame member 301 rotates in the second axis direction (sub-scanning direction) due to the warp deformation of the piezoelectric member group 303. That is, in the optical deflector 100, the mirror is deflected while scanning the reflected light direction of the incident light in the biaxial direction by rotating the mirror in the biaxial direction (the first axial direction and the second axial direction). The optical deflector 100 projects an image on a projection surface, for example, by light deflection in two axial directions. The voltage supply unit 201 is a pad for supplying a voltage to be applied to each constituent member, and is connected to each constituent member by wiring configured on the substrate. The wiring will be described later.

  The voltage applied to the piezoelectric member 104 for causing the rotation of the uniaxial mirror corresponding to the main scanning direction is applied between the electrodes located above and below the piezoelectric member 104, and is determined from the frame rate of the image. A sine wave voltage is applied at a frequency. For example, the driving frequency is a relatively high frequency such as 20 kHz. By setting the drive frequency to a frequency close to the resonance frequency determined from the weight of the mirror unit 103 and the spring constant of the torsion bar 110, the mirror can be resonated and rotated, so at a relatively low voltage, A high deflection angle of the mirror can be generated.

  The piezoelectric member group 303 is connected to two types of drive voltage sources every other beam of the cantilever group 302. FIG. 2 shows the cantilever group 302 as a cantilever group 304 and a cantilever group 305 depending on the driving voltage source, and the piezoelectric member group 303 is divided into a piezoelectric member group 306 and a piezoelectric member group 307 according to the connected driving voltage source. It shows with. As shown in FIG. 2 with the same pattern for the piezoelectric member group having the same driving voltage source, the piezoelectric member group 306 and the piezoelectric member group 307 are alternately provided for every other beam of the cantilever group 302. The piezoelectric member group 306 and the piezoelectric member group 307 are connected so that a voltage is applied in parallel for each group, as will be described in detail later. The mirror frame member 301 rotates in another axial direction (sub-scanning direction) different from the one-axis direction due to warpage deformation of each of the piezoelectric member groups 303 (piezoelectric member group 306 and piezoelectric member group 307). Note that “a” and “b” that are both ends of the mirror unit 103 illustrated in FIG. 2 and “X-X ′ cross section” will be described later.

  Here, the piezoelectric member group 306 and the piezoelectric member group 307 correspond to “first piezoelectric member” and “second piezoelectric member” or “second piezoelectric member” and “first piezoelectric member”, respectively. To do.

  FIG. 3 is an excerpt of the upper surface of the mirror frame member 301. 4 is a cross-sectional view taken along the line L-L ′ shown in FIG. 3. FIG. 5 is a cross-sectional view taken along the line M-M ′ shown in FIG. 3. 6 is a cross-sectional view taken along line N-N ′ shown in FIG. 3. In the L-L ′ sectional view (see FIG. 4) and the M-M ′ sectional view (see FIG. 5), the cantilever 109 that generates the driving force for rotating the mirror, that is, the piezoelectric member 104 is mainly shown. In the N-N ′ sectional view (see FIG. 6), the mirror unit 103 is shown. Below, the basic manufacturing method of the optical deflector 100 comprised on a silicon substrate (substrate | substrate 101) is demonstrated using FIGS. In addition, although the figure around the mirror frame member 301 is shown here as an example, the manufacturing method of the meander-shaped cantilever group 302, the outer peripheral substrate 101, and the like are basically the same. In FIG. The same number is attached | subjected to the part corresponding to the member 301 periphery.

  An SOI substrate is used as the silicon substrate (substrate 101). The substrate 101 which is an SOI substrate is composed of silicon 102 on the active layer side, a buried oxide film layer 116, and silicon 105 on the base material layer side. The buried oxide film layer 116 may be referred to as a “BOX layer”. First, a silicon oxide film 107 is formed on the SOI surface, followed by a lower electrode material 120 (may be referred to as “lower electrode 120” as appropriate), a piezoelectric material 121, an upper electrode material 122 (as appropriate as “upper electrode”). The film is formed in order. Thereafter, the upper electrode material 122, the piezoelectric material 121, and the lower electrode material 120 are patterned in different patterns. At this time, each pattern is patterned in an arbitrary form according to the performance required for the optical deflector 100, and the silicon oxide film 107 is etched in the same pattern as the lower electrode material 120.

  Then, the insulating film 108 is formed, the connection hole 112 is opened, and the lead wiring material 111 is formed and patterned. Subsequently, a passivation film 113 and a mirror film (mirror part 103) are formed and sequentially patterned. Thereafter, the optical deflector 100 is completed by sequentially patterning and etching the active layer 102 (silicon on the active layer side), the base material layer 105 (silicon on the base material layer side), and the buried oxide film layer 116. To do. The method of dividing into chips from the wafer may be realized by a dicing technique using a blade, a laser dicing technique, a dry etching technique, or the like. By applying a sine wave driving voltage between the lower electrode material 120 and the upper electrode material 122, the piezoelectric material 121 expands and contracts in the plane direction, causing warpage of the piezoelectric member 104, and twisting the torsion bar 110. Raising and inducing resonance vibration of the mirror unit 103 to cause the mirror unit 103 to rotate in the main scanning direction (see FIG. 6).

  Next, a structure for generating rotation in another axial direction (sub-scanning direction) different from rotation in one axial direction will be described with reference to FIGS. FIG. 7 is a cross-sectional view of the optical deflector 100 taken along X-X ′ (see FIG. 2). FIG. 8 is a schematic diagram of electrical wiring for displacing the cantilever group 302.

  As shown in FIG. 7, two sets of left and right meander-shaped cantilever groups 302 configured by a plurality of numbers are connected at one end to a mirror frame member 301 having a mirror portion 103 and the other end. Is connected to the substrate 101. Two pairs of meander-shaped cantilever groups 302 are arranged at every other pair (that is, cantilever group 304 and cantilever group 305), and piezoelectric member group 303 (respectively, piezoelectric member group 306, which serves as means for generating warp deformation of the beam). And a piezoelectric member group 307). In the two left and right cantilever groups 302, the piezoelectric member group 306 and the piezoelectric member group 307 have different driving voltages (the first driving voltage and the second driving voltage, or the second driving voltage and the first driving). Voltage) is applied individually. Due to the warp deformation of the piezoelectric member group 303, the cantilever group 304 and the cantilever group 305 move differently, and the mirror frame member 301 rotates in another axial direction different from the one axial direction.

  FIG. 8 is a diagram illustrating an example of electrical wiring between the piezoelectric member group 306 and the piezoelectric member group 307 of the two right and left cantilever groups 302. As shown in FIG. 8, in the left and right cantilever groups 302, the upper electrode 122 and the lower electrode 120 for the piezoelectric member group 306b (306), and the upper electrode 122 and the lower electrode 120 for the piezoelectric member group 307b (307). It is a separate wiring. That is, adjacent cantilevers (cantilever group 304 and cantilever group 305) can be driven separately. In FIG. 8, the piezoelectric member group 306 and the piezoelectric member group 307 are connected in parallel, and both the upper electrodes 122 of the piezoelectric member group 306 and the piezoelectric member group 307 are grounded by a common line (common line). ing. Regarding the lower electrode 120 of the piezoelectric member group 306b and the piezoelectric member group 307b. Each common line is individually connected to each pad of the voltage supply unit 201 (see FIG. 2). In FIG. 8, as an example, a pad that applies a voltage to the lower electrode 120 of the piezoelectric member group 306b is shown as a lower electrode A (306c), and a pad that applies a voltage to the lower electrode 120 of the piezoelectric member group 307b is a lower electrode B. (307c).

  By applying a driving voltage to the piezoelectric member group 306 and the piezoelectric member group 307, the displacement of the cantilever group 304 and the cantilever group 305 gradually increases from the portion connected to the substrate 101, and the portion that contacts the mirror frame member 301. The displacement of becomes the maximum. Thereby, unlike the rotation of the mirror in the main scanning direction, a relatively large rotation can be generated without depending on the resonance vibration. The electrical wiring is not limited to that shown in FIG.

  FIG. 9 is a diagram showing an equivalent circuit of the piezoelectric member group 306 and the piezoelectric member group 307 provided with the electrical wiring shown in FIG. In FIG. 9, the driving voltage source of the driver that drives the optical deflector 100 supplies voltage for one set (here, the left cantilever group 302-1) of the two left and right cantilever groups 302 shown in FIG. 6 shows an equivalent circuit when connected through the pads of the unit 201 (see FIG. 2). Although the description is omitted below, what is described in the left cantilever group 302-1 is the same for the right cantilever group 302-2.

  FIG. 9 shows an equivalent circuit in which the piezoelectric member group 306 and the piezoelectric member group 307 are simply replaced with a capacitor C. Note that the upper and lower arrangements of the upper electrode 122 and the lower electrode 120 shown in FIG. 9 are opposite to those in FIG.

  In FIG. 9, the plus side of the driving voltage source 10 </ b> A is connected to the lower electrode 120 of the piezoelectric member group 306. The negative side of the drive voltage source 10A is connected to the piezoelectric member group 306 and the upper electrode 122 of the piezoelectric member group 307 and is grounded. The drive voltage source 10A applies a sawtooth voltage having a drive waveform 11A to the circuit through the lower electrode A (see FIG. 8).

  The plus side of the other drive voltage source 10B is connected to the lower electrode 120 of the piezoelectric member group 307. The negative side of the drive voltage source 10B is connected to the piezoelectric member group 306 and the upper electrode 122 of the piezoelectric member group 307 and is grounded. The drive voltage source 10B is connected to the lower electrode B (see FIG. 8), and applies a sawtooth voltage of the drive waveform 11B to the circuit. The drive waveform 11A and the drive waveform 11B are sawtooth waves that are symmetrical to each other in the time axis direction.

In FIG. 9, the current flowing through the wiring to the lower electrode 120 of the piezoelectric member group 306 is I _A , and the current flowing through the wiring to the lower electrode 120 of the piezoelectric member group 307 is I _B. In this case, the current I _A flows into each capacitor C corresponding to the piezoelectric member group 306 as a branch current (current I _A1 , current I _A2 , current I _A3 , current I _A4 ). The current I _B flows as a branch current (current I _B1 , current I _B2 , current I _B3 , current I _B4 ) into each capacitor C corresponding to the piezoelectric member group 307. Therefore, in the common wiring connecting the upper electrodes 122 of the piezoelectric member group 306 and the piezoelectric member group 307, the currents flowing into the piezoelectric member group 306 and the piezoelectric member group 307 are both current I _C (= current I _A + current I _B ) Will flow out. That is, the peak current of the common wiring is higher than that of one type of driving waveform due to the overlap of the driving waveform 11A applied to the piezoelectric member group 306 and the driving waveform 11B applied to the piezoelectric member group 307. In the present embodiment, this peak current is reduced. This will be described in more detail below.

  FIG. 10 is a detailed explanatory diagram of the drive waveform 11A and the drive waveform 11B. FIG. 10 shows the drive waveform 11A and the drive waveform 11B superimposed on the time axis. The drive waveform 11A and the drive waveform 11B are sawtooth waves having different shapes, and change together along the time axis as shown in FIG. Each of the drive waveforms 11A and 11B is formed by changing the voltage value in a stepwise manner at a certain time interval T (“time interval to be changed at predetermined time intervals”).

  In the present embodiment, the time Tsa is from the timing t1 when the voltage value of the drive waveform 11A changes to the timing t2 when the voltage value of the drive waveform 11B changes, and the drive waveform 11A starts from the timing t3 when the voltage value of the drive waveform 11B changes. The time Tsb is the time until the timing t4 when the voltage value changes. Then, the D / A 521 (see FIG. 1) is set such that the time Tsa and the time Tsb are an optimal combination for reducing the peak current value. The peak current value differs according to the difference in each signal change pattern between the drive waveform 11A and the drive waveform 11B in the same time zone (hereinafter referred to as a region) on the time axis.

  FIG. 11 is a diagram for explaining that the peak current value varies depending on the region of the drive waveform. In FIG. 11, paying attention to the slopes of the drive waveform 11A and the drive waveform 11B, it will be explained that the areas are divided by combinations of slopes, and the direction of the current flowing through the common wiring is different depending on each area.

  The first region is a time zone in which the voltages of the drive waveform 11A and the drive waveform 11B rise together. Therefore, a positive current flows from both the drive voltage source 10A and the drive voltage source 10B, and the sum of these currents flows in the positive direction through the grounded common wiring.

  In the second region, the driving waveform 11A is a rising time zone, and the driving waveform 11B is a falling time zone. For this reason, a positive current flows from the drive voltage source 10A, a negative current flows from the drive voltage source 10B, and the current of the drive voltage source 10B from the current of the drive voltage source 10B flows to the grounded common wiring. The current minus the current flows.

  The third region is a time zone during which the voltages of the drive waveform 11A and the drive waveform 11B both decrease. For this reason, a negative current flows from both the drive voltage source 10A and the drive voltage source 10B, and the sum of these currents flows in the negative direction through the grounded common wiring.

  Subsequently, an optimal combination of values of time Tsa and time Tsb will be described. In the following, for easy understanding, in the equivalent circuit shown in FIG. 9, an equivalent circuit in which only one pair in the cantilever group 302-1 is cut out, that is, in the piezoelectric member group 306 and the piezoelectric member group 307, is shown. Description will be made using an equivalent circuit in which only one pair is cut out.

  FIG. 12 is a diagram showing an equivalent circuit in which only one pair of cantilever groups is cut out. FIG. 13 is a diagram illustrating an example of a relationship between peak current values in each region (first region, second region, and third region) when the drive waveform 11A and the drive waveform 11B are formed at the same timing. FIG. 14 is a diagram illustrating an example of a relationship between peak current values in each region (first region, second region, and third region) when the drive waveform 11A and the drive waveform 11B are formed at different timings. Here, FIG. 13 is used as a comparison diagram of FIG. 14 showing the optical scanning device according to the present embodiment. 13 and 14 will be described based on the equivalent circuit of FIG.

FIG. 13 shows drive voltage waveforms (drive waveform 11A and drive waveform 11B) and current waveforms in each region (first region, second region, and third region) when time Tsa = 0 and time Tsb = T. Are shown side by side. As shown in FIG. 13, the first region and the third region are a time zone in which the drive waveform 11A and the drive waveform 11B both rise and fall. For this reason, the current I _A1 (see FIG. 12) and the current I _B2 (see FIG. 12) simultaneously flow in the same direction, and the current peak value flowing in the current I _C (see FIG. 12) becomes the current as shown in FIG. IPeaak (A1) that is the peak current value of I _A1 and IPeak (B1) that is the peak current value of current I _B1 are added together, and the peak current is maximized.

FIG. 14 shows drive voltage waveforms (drive waveform 11A and drive waveform 11B) and current waveforms in each region (first region, second region, and third region) when time Tsa> K1 and time Tsb> K2. Are shown side by side. However, K1 is the time until the current I _A1 becomes 1/2 or less of IPeak (A1), and K2 is the time until the current I _B1 becomes 1/2 or less of IPeak (B1). And

In FIG. 14, the timing for switching the voltage values of the drive waveform 11A and the drive waveform 11B is relative so that the step of the voltage value is switched after each current (current I _A1 and current I _A2 ) becomes less than half of the peak value. Are staggered. In this example, every time the voltage value of the drive waveform 11A is switched, the voltage value of the drive waveform 11B is switched within a period in which the current I _A1 is reduced to half or less from the peak value. Further, every time the voltage value of the drive waveform 11B is switched, the voltage value of the drive waveform 11A is switched within a period in which the current I _B1 is reduced to half or less from the peak value. For this reason, the timing of the peak of the current value at which the current I _A1 and the current I _B1 reach each other is shifted, and in this case, at most, 1/2 of the peak value of the current I _A1 and 1 / of the peak value of the current I _B1 2 is the peak value of the current I _C1 flowing in the common wiring. In other words, both the peak value of the current I _C1 flowing through the common wiring is prevented from being greater than or equal to the peak value of the current I _{A1 and} the peak value of the current I _B1 are both suppressed.

In addition, when the time interval T for changing the voltage value stepwise is short and it is not possible to secure the time when each current (current I _A1 and current I _B1 ) is half of the peak value as time Tsa and time Tsb, Let Tsa = Tsb = 1 / 2T. Even in this case, there is an effect of reducing the peak value of the current I _C1 flowing through the common wiring.

As described above, in the present embodiment, the timing of changing the voltage values of the drive waveform 11A and the drive waveform 11B applied to different piezoelectric member groups is relatively shifted to flow through the common wiring of each piezoelectric member group. It becomes possible to reduce the peak value of the current I _C1 . Therefore, an increase in the peak value of current in the optical deflector wiring such as a MEMS mirror is suppressed, and heat generation of the wiring is reduced, so that thermal damage is prevented, and further, the wiring density is increased and the wiring is further increased. Design flexibility such as narrowing is also improved.

(Second Embodiment)
In the first embodiment, the optical scanning device has been described. In the second embodiment, an image display device including the optical scanning device according to the first embodiment will be described. Here, an example of application to a head-up display which is a laser scanning image display device as an image display device is shown.

  FIG. 15 is a diagram illustrating a head-up display having an optical scanning device. The head-up display is, for example, an image mounted on a non-moving body such as a moving body such as a vehicle, an aircraft, a ship, a mobile robot, or a working robot that operates a driving target such as a manipulator without moving from the spot. It can also be applied as a display device. Here, an example in which a head-up display is mounted on an automobile is shown. An automobile has a power source such as a motor and an engine and a power source such as a battery as a “moving means”, and an image described later is displayed on the windshield by the power from the power source after the motor and the engine are started. To do. The automobile travels by obtaining driving force from a power source, and image display during traveling can be selected.

  As shown in FIG. 15, the head-up display 1901 includes an optical scanning device 1902, a “display device”, a scanning mirror 1903, a screen 1904 that is a surface to be scanned, and a concave mirror 1906. Wind shield) 1905 is irradiated with light. The windshield 1905 also functions as a transmission / reflection member that transmits part of the incident light and reflects at least part of the remaining part. For this reason, the virtual image I is visually recognized from the viewpoint of the driver H. The optical scanning device 1902 includes a plurality of light source elements 600 having one or a plurality of light emitting points. For example, the light source element 600 is a red, blue, and green semiconductor laser, and the three colors of red, blue, and green deflected light emitted from each light source element in a time division manner are transmitted through the optical system 601 to the optical deflector 100. It is guided to the reflecting surface (mirror) as mixed light. The mixed light is deflected by the mirror of the optical deflector 100 and is folded by the scanning mirror 1903 to draw a two-dimensional image (intermediate image) on the screen 1904.

  The screen 1904 has a function of diverging laser light at a desired divergence angle, and preferably has a microlens array structure. The light beam emitted from the screen 1904 is enlarged and displayed through the single concave mirror 1906 and the windshield 1905. The single concave mirror 1906 is designed and arranged so as to correct an optical distortion element in which the horizontal line of the intermediate image is convex upward or downward due to the influence of the windshield 1905. In addition, the structure which has another partial reflection mirror (combiner) which has the same function (partial reflection) as the windshield 1905 may be sufficient. The head-up display 1901 can project a high-intensity image in any limited direction while maintaining high image quality. For example, navigation information (information such as speed and travel distance) for driving a car can be displayed. In order to improve visibility, it can be displayed with high brightness. In the case of an apparatus that projects an image by performing optical scanning using the optical scanning apparatus 1902, for example, a projector that projects an image on a display screen or a reflective transmission that a mounting member mounted on an observer's head or the like has. The present invention can be similarly applied to a head mounted display that projects an image on a screen such as a member.

  Also in the second embodiment, since the optical scanning device of the first embodiment is used, the same effect as the first embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Optical scanning device 100 Optical deflector 500 Drive control part 510 FPGA
520 Driver 521 D / A
522 operational amplifier

JP 2017-138375 A

Claims (8)

An optical deflector and a controller for controlling the driving of the optical deflector;
The optical deflector is
A mirror part having a mirror surface, and a meander-shaped cantilever that rotatably supports the mirror part;
A first piezoelectric member and a second piezoelectric member that cause warping deformation of the cantilever;
Common wiring connected to electrodes on one end side of the first piezoelectric member and the second piezoelectric member;
Have
The controller is
The timing for changing the first driving voltage applied to the first piezoelectric member and the timing for changing the second driving voltage applied to the second piezoelectric member are relatively shifted.
An optical scanning device. 2. The optical scanning device according to claim 1, wherein the driving voltage waveform of the first driving voltage and the driving voltage waveform of the second driving voltage overlap a time zone in which the voltage rises and a time zone in which the voltage falls. . The timing for changing the second drive voltage relative to the timing for changing the first drive voltage is:
3. The optical scanning device according to claim 1, wherein when the first drive voltage is changed, the current value flowing in the common wiring is longer than a time period during which the current value drops to half or less of a peak value. 4. The timing for changing the second driving voltage with respect to the timing for changing the first driving voltage is half of a time interval for changing the first driving voltage in a predetermined time interval. Or the optical scanning device of 2. The optical deflector is
A cantilever component that rotates the mirror portion around a rotation axis in a direction different from a rotation axis that is rotatably supported by the meander-shaped cantilever;
The optical scanning device according to claim 1, wherein the optical scanning device is an optical scanning device. The meander-shaped cantilever is
The first piezoelectric member and the second piezoelectric member are alternately provided every other beam of the cantilever.
The optical scanning device according to claim 5. An optical scanning device according to any one of claims 1 to 6,
A display device for displaying the light emitted from the optical scanning device as an image;
An image display device comprising: An optical scanning device according to any one of claims 1 to 6,
A display device for displaying the light emitted from the optical scanning device as an image;
And a moving means that moves while displaying the image.

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