JP7059713B2 - Optical scanning device, image display device, and moving object - Google Patents

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 drive voltage for driving a MEMS (Micro Electro Mechanical Systems) mirror has been studied.

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

However, the conventional drive voltage application technique has a problem that the peak value of the current increases in the wiring for applying the drive 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 the peak value of a current in a wiring that applies a driving voltage to an optical deflector. With the goal.

In order to solve the above-mentioned problems and achieve the object, the optical scanning device according to the embodiment of the present invention includes an optical deflector and a control unit for controlling the drive of the optical deflector, and the optical deflection The vessel 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 piezoelectric member. The control unit has a first drive voltage applied to the first piezoelectric member and the second drive voltage , which has a piezoelectric member and a common wiring connected to an electrode on one end side of the second piezoelectric member. The second drive voltage to which the piezoelectric member is applied is changed stepwise in a predetermined time step, and the timing at which the first drive voltage applied to the first piezoelectric member is changed in a predetermined time step and the second It is characterized in that the timing of changing the second drive voltage to which the piezoelectric member is applied is relatively different from the timing of changing the second drive voltage in the predetermined time interval .

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 drive voltage to the optical deflector.

FIG. 1 is a diagram showing an example of an optical scanning apparatus 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. FIG. 4 is a cross-sectional view taken along the line L-L'shown in FIG. FIG. 5 is a cross-sectional view taken along the line MM'shown in FIG. FIG. 6 is a cross-sectional view taken along the line N—N ′ shown in FIG. FIG. 7 is a cross-sectional view taken along the line XX'(see FIG. 2) of the optical deflector. 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 to which the electrical wiring shown in FIG. 8 is applied. FIG. 10 is a detailed explanatory diagram of the drive waveform. FIG. 11 is a diagram illustrating that the peak current value differs depending on the region of the drive waveform. FIG. 12 is a diagram showing an equivalent circuit obtained by cutting out only one pair of cantilever groups. FIG. 13 is a diagram showing an example of the relationship between peak current values in each region (first region, second region, third region) when two drive waveforms are formed at the same timing. FIG. 14 is a diagram showing an example of the relationship between peak current values in each region (first region, second region, 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. The present invention is not limited to the following embodiments.

(First Embodiment)
FIG. 1 is a diagram showing an example of an optical scanning apparatus 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, and the optical deflector 100 rotates a mirror by a drive signal from the drive control unit 500. , Optical scanning.

The optical deflector 11 may include a configuration in which light scanning is performed in the uniaxial direction using a cantilever in the shape of a meander. Here, as an example, a configuration in which optical scanning is performed in two axial directions of a main scanning direction and a sub-scanning direction is shown, but the present invention is not limited to this. Further, 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 for optical scanning, an optical system for guiding the light of the light source to the 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 / A521 and an 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 and the sub-scanning direction to the D / A521. The D / A521 converts the drive voltage signal from digital to analog and outputs it to the operational amplifier 522. The operational amplifier amplifies the analog drive voltage signal output from the D / A521 with a predetermined gain and applies it 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 the meander-shaped cantilever as an actuator for rotating the mirror. The piezoelectric members warp and deform the cantilever due to different deformations, and 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, the timing of changing the first drive voltage applied to the first piezoelectric member or the timing of changing the second drive voltage of applying the second piezoelectric member will be described. do. Here, as an example, with respect to a device in which the drive control unit 500 changes the first drive voltage and the second drive voltage stepwise in predetermined time intervals, the timing at which the first drive voltage is changed and the second drive voltage are changed. By relatively shifting the timing of changing the voltage, the peak value of the current flowing through the common wiring is reduced. The relative shift is performed by D / A521. The amount of shift may be set to D / A521 in advance, or may be set from FPGA510 to D / A521.

FIG. 2 is a schematic top view of the optical deflector 100. As shown in FIG. 2, the optical deflector 100 includes rotation of a mirror in one axis direction (first axis) corresponding to the main scanning direction and another axial direction (second axis) corresponding to the sub-scanning direction. A cantilever structure is constructed that allows the rotation of the mirror. Specifically, the rotation of the mirror in the main scanning direction includes a substrate 101 (SOI substrate: Silicon On Insulator), a mirror portion 103 having a mirror surface, and a torsion bar (mirror support portion) 110 that supports the mirror portion 103. , The cantilever 109 and the piezoelectric member 104 that causes warpage deformation in the cantilever 109 make it 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 cantilever (hereinafter, referred to as a cantilever group) 302 having a meander shape composed of a plurality of beams. The other end of the cantilever group 302 having a meander shape is connected to the outer peripheral substrate 101. On the cantilever group 302 having a meander shape, the piezoelectric member group 303 exists as a means for causing warp deformation on a plurality of beams. As a result, the mirror frame member 301 is rotatably supported in the second axial direction.

The mirror frame member 301 rotates in the second axial direction (sub-scanning direction) due to the warp deformation of the piezoelectric member group 303. That is, the optical deflector 100 deflects the incident light while scanning the reflected light direction in the biaxial direction by rotating the mirror in the biaxial direction (first axial direction and the second axial direction). The light deflector 100 projects an image onto a projection surface, for example, by light deflection in the biaxial direction. The voltage supply unit 201 is a pad for supplying a voltage applied to each component, and is connected to each component 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 mirror in the uniaxial direction corresponding to the main scanning direction is applied between the electrodes located above and below the piezoelectric member 104, and is a drive determined from the frame rate of the image. A sine wave voltage is applied at the frequency. For example, the drive frequency is a relatively high frequency such as 20 kHz. By setting the drive frequency to a frequency close to the resonance frequency determined by the weight of the mirror unit 103 and the spring constant of the torsion bar 110, the mirror can be resonated and rotated, so that the mirror can be rotated at a relatively low voltage. It is possible to generate a high deflection angle of the mirror.

The piezoelectric member group 303 is connected to two types of drive voltage sources every other beam of the cantilever group 302. In FIG. 2, the cantilever group 302 is shown by the cantilever group 304 and the cantilever group 305 depending on the difference in the drive voltage source, and the piezoelectric member group 303 is shown by the piezoelectric member group 306 and the piezoelectric member group 307 according to the connected drive voltage source. It is shown by. As shown in FIG. 2 with the same pattern for the piezoelectric member group having the same drive voltage source, the piezoelectric member group 306 and the piezoelectric member group 307 are alternately provided on every other beam of the cantilever group 302, respectively. The piezoelectric member group 306 and the piezoelectric member group 307 are connected so that a voltage is applied in parallel to each group, which will be described in detail later. The mirror frame member 301 rotates in another axial direction (sub-scanning direction) different from the uniaxial direction due to the warp deformation of each of the piezoelectric member group 303 (piezoelectric member group 306 and piezoelectric member group 307). The "a" and "b" at both ends of the mirror portion 103 shown in FIG. 2 and the "XX'cross section" will be described later.

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

FIG. 3 is an excerpt of the upper surface of the mirror frame member 301. FIG. 4 is a cross-sectional view taken along the line L-L'shown in FIG. FIG. 5 is a cross-sectional view taken along the line MM'shown in FIG. FIG. 6 is a cross-sectional view taken along the line N—N ′ shown in FIG. The LL'cross-sectional view (see FIG. 4) and the MM'cross-sectional view (see FIG. 5) mainly represent a cantilever 109, that is, a piezoelectric member 104, which generates a driving force for rotating a mirror. In the NN'cross-sectional view (see FIG. 6), the mirror portion 103 is represented. Hereinafter, a basic manufacturing method of the optical deflector 100 configured on the silicon substrate (substrate 101) will be described with reference to FIGS. 3 to 6. Here, the figure around the mirror frame member 301 is shown as an example, but other than that, the manufacturing method of the cantilever group 302 having a meander shape and the outer peripheral substrate 101 is basically the same, and in FIG. 7, the mirror frame is shown. The same number is given to the part corresponding to the circumference of the member 301.

An SOI substrate is used for the silicon substrate (substrate 101). The substrate 101, which is an SOI substrate, is composed of silicon 102 on the active layer side, an embedded oxide film layer 116, and silicon 105 on the substrate layer side. The embedded oxide film layer 116 may be referred to as a "BOX layer". First, a silicon oxide film 107 is formed on the surface of the SOI, followed by a lower electrode material 120 (appropriately referred to as "lower electrode 120"), a piezoelectric material 121, and an upper electrode material 122 (appropriately, "upper electrode". 122 ”) is formed in order. After that, 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 shape according to the performance required for the optical deflector 100, and the silicon oxide film 107 is etched with 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, the passivation film 113 and the mirror film (mirror portion 103) are formed into a film and sequentially patterned. After that, the light 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 embedded oxide film layer 116. do. The method of individualizing the 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 drive 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 the piezoelectric member 104 to warp and twisting the torsion bar 110. Raise and induce the resonance vibration of the mirror unit 103 to cause the mirror unit 103 to rotate in the main scanning direction (see FIG. 6).

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

As shown in FIG. 7, one end of each of the left and right two sets of cantilever groups 302 having a shape of a cantilever, which is composed of a plurality of numbers, is connected to a mirror frame member 301 having a mirror portion 103, and the other end is connected to the mirror frame member 301. Is connected to the substrate 101. The two sets of cantilever groups 302 having a minanda shape are every other one (that is, the cantilever group 304 and the cantilever group 305), and the piezoelectric member group 303 (respectively, the piezoelectric member group 306) is a means for causing warp deformation in the beam. , Has a piezoelectric member group 307). In the two sets of left and right cantilever groups 302, the drive voltage (first drive voltage and second drive voltage, or second drive voltage and first drive) having different waveforms is different between the piezoelectric member group 306 and the piezoelectric member group 307. 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 showing an example of electrical wiring between the piezoelectric member group 306 and the piezoelectric member group 307 of the two sets of left and right cantilever groups 302. As shown in FIG. 8, in the two sets of 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 different wiring from. That is, the adjacent cantilever (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 wire wiring (common wiring). 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 for applying a voltage to the lower electrode 120 of the piezoelectric member group 306b is shown as a lower electrode A (306c), and a pad for applying a voltage to the lower electrode 120 of the piezoelectric member group 307b is shown as a lower electrode B. It is shown as (307c).

By applying a driving voltage to the piezoelectric member group 306 and the piezoelectric member group 307, the displacement gradually increases from the portion connected to the substrate 101 in the cantilever group 304 and the cantilever group 305, and the portion in contact with the mirror frame member 301. Displacement is maximum. As a result, 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 with the electrical wiring shown in FIG. In FIG. 9, the drive voltage source of the driver for driving the optical deflector 100 supplies voltage to one of the two left and right cantilever groups 302 shown in FIG. 8 (here, the left cantilever group 302-1). The equivalent circuit when connected through the pad of the part 201 (see FIG. 2) is shown. Although the description is omitted below, the same can be said for the cantilever group 302-2 on the right side as described in the cantilever group 302-1 on the left side.

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. The vertical arrangement of the upper electrode 122 and the lower electrode 120 shown in FIG. 9 is opposite to that of FIG. 8 because FIG. 8 is turned upside down.

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

The positive side of the other drive voltage source 10B is connected to the lower electrode 120 of the piezoelectric member group 307. Further, the negative side of the drive voltage source 10B is connected to the upper electrode 122 of the piezoelectric member group 306 and 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 the sawtooth voltage of the drive waveform 11B to the circuit. The drive waveform 11A and the drive waveform 11B are sawtooth waves having shapes symmetrical with 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 referred to as _IA , and the current flowing through the wiring to the lower electrode 120 of the piezoelectric member group 307 is referred to as _IB . In this case, the current _IA flows into each capacitor C corresponding to the piezoelectric member group 306 as a branch current (current _IA1 , current _IA2 , current _IA3 , current _IA4 ). Further, the current _IB flows into each capacitor C corresponding to the piezoelectric member group 307 as a branch current (current _IB1 , current _IB2 , current _IB3 , current _IB4 ). Therefore, in the common wiring connecting the upper electrodes 122 of the piezoelectric member group 306 and the piezoelectric member group 307, the current flowing into the piezoelectric member group 306 and the piezoelectric member group 307 is both current _IC (= current I _A + current _IB ). ) Will flow out. That is, in the common wiring, the peak current is higher than that of one type of drive waveform due to the overlap of the drive waveform 11A applied to the piezoelectric member group 306 and the drive waveform 11B applied to the piezoelectric member group 307. In this embodiment, this peak current is reduced. This will be described in more detail below.

FIG. 10 is a detailed explanatory view of the drive waveform 11A and the drive waveform 11B. In FIG. 10, the drive waveform 11A and the drive waveform 11B are shown superimposed on the time axis. The drive waveform 11A and the drive waveform 11B are sawtooth waves having different shapes, and as shown in FIG. 10, they change together along the time axis. The drive waveforms 11A and 11B are formed by gradually changing the voltage value at a certain time interval T (“time interval that changes in predetermined time intervals”).

In the present embodiment, the time Tsa is from the timing t1 at which the voltage value of the drive waveform 11A changes to the timing t2 at which the voltage value of the drive waveform 11B changes, and from the timing t3 where the voltage value of the drive waveform 11B changes to the drive waveform 11A. The time Tsb is up to the timing t4 when the voltage value of is changed. Then, the D / A 521 (see FIG. 1) is set so that the time Tsa and the time Tsb are the optimum combination for reducing the peak current value. The peak current value differs depending on the difference in each signal change pattern of 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 illustrating that the peak current value differs depending on the region of the drive waveform. In FIG. 11, attention is paid to the inclination of the drive waveform 11A and the drive waveform 11B, and the regions are divided according to the combination of inclinations, and the direction of the current flowing through the common wiring differs depending on each region.

The first region is a time zone in which the voltages of the drive waveform 11A and the drive waveform 11B both rise. 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 in the grounded common wiring.

In the second region, the drive waveform 11A is a rising time zone, and the driving waveform 11B is a falling time zone. Therefore, 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 10A to the drive voltage source 10B is connected to the grounded common wiring. The current minus the current flows.

The third region is a time zone in which the voltages of the drive waveform 11A and the drive waveform 11B both decrease. Therefore, a current in the negative direction 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 in the grounded common wiring.

Subsequently, the combination of the optimum values of the time Tsa and the time Tsb will be described. In the following, in order to make the explanation easier to understand, in the equivalent circuit shown in FIG. 9, the equivalent circuit obtained by cutting out only one pair of the cantilever group 302-1, that is, the piezoelectric member group 306 and the piezoelectric member group 307. An equivalent circuit obtained by cutting out only one pair will be described.

FIG. 12 is a diagram showing an equivalent circuit obtained by cutting out only one pair of cantilever groups. FIG. 13 is a diagram showing an example of the relationship between peak current values in each region (first region, second region, third region) when the drive waveform 11A and the drive waveform 11B are formed at the same timing. FIG. 14 is a diagram showing an example of the relationship between peak current values in each region (first region, second region, 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 apparatus according to the present embodiment. 13 and 14 will be described based on the equivalent circuit of FIG.

FIG. 13 shows the drive voltage waveforms (drive waveforms 11A and drive waveforms 11B) and current waveforms of each region (first region, second region, third region) when the time Tsa = 0 and the 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. Therefore, the current _IA1 (see FIG. 12) and the current _IB2 (see FIG. 12) flow in the same direction at the same time, and the current peak value flowing in the current _IC (see FIG. 12) is the current as shown in FIG. IPeek (A1), which is the peak current value of I _A1 , and IPeek ( _B1 ), which is the peak current value of the current IB1, are added together, and the peak current is maximized.

FIG. 14 shows the drive voltage waveforms (drive waveforms 11A and drive waveforms 11B) and current waveforms of each region (first region, second region, third region) when the time Tsa> K1 and the time Tsb> K2. Are shown side by side. However, K1 is the time until the current I _A1 becomes ½ or less of IPeak (A1), and K2 is the time until the current IB1 becomes ½ or less of IPeak ( _B1 ). And.

In FIG. 14, the timing of switching the voltage value between 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 half or less from the peak value. The target is shifted. In this example, each 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 _IA1 drops to less than half from the peak value. Further, each time the voltage value of the drive waveform 11B is switched, the voltage value of the drive waveform _11A is switched within the period in which the current IB1 drops to half or less from the peak value. Therefore, the timings of the peaks of the current values reached by the currents I _A1 and the current I _B1 are different from each _{other .} The addition with 2 is the peak value of the current _IC1 flowing in the common wiring. That is, it is suppressed that the peak value of the current _{IC1 flowing in the common wiring becomes equal to or higher than the peak value of the current I A1 and} the peak value of the current I _B1 becomes higher than the peak value.

If the time interval T for gradually changing the voltage value is short and it is not possible to secure the time for each current (current I _A1 and current I _B1 ) to be half of the peak value as time Tsa and time Tsb, Tsa = Tsb = 1 / 2T. Even in this case, there is an effect of reducing the peak value of the current _IC1 flowing through the common wiring.

As described above, in the present embodiment, the timing for changing the voltage values of the drive waveform 11A and the drive waveform 11B applied to different piezoelectric member groups is relatively shifted, so that the current flows through the common wiring of each piezoelectric member group. It becomes possible to reduce the peak value of the current _IC1 . Therefore, the increase in the peak value of the current in the wiring of the optical deflector such as the MEMS mirror is suppressed, the heat generation of the wiring is reduced, the thermal damage is prevented, the wiring density is increased, and the wiring is further increased. The degree of freedom in design such as narrowing is also improved.

(Second embodiment)
In the first embodiment, the optical scanning device has been described. In the second embodiment, the image display device including the optical scanning device of 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 an image mounted on a moving object such as a vehicle, an aircraft, a ship, or a mobile robot, or a non-moving object such as a working robot that operates a drive 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 or engine and a power source such as a battery as a "means of transportation", and after the motor or engine is started, an image described later is displayed on the windshield by electric power from the power source. do. Then, the automobile travels by obtaining a driving force from a power source, and it is possible to select the display of an image during traveling.

As shown in FIG. 15, the head-up display 1901 includes an optical scanning device 1902, a scanning mirror 1903 as a "display device", a screen 1904 to be scanned, and a concave mirror 1906, and has a front glass (front). Windshield) Irradiates 1905 with light. The windshield 1905 also functions as a transmissive reflective member that transmits a part of the incident light and reflects at least a part of the rest. Therefore, 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 a single 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 polarized light emitted from each light source element in a time-divided manner are transmitted through the optical system 601 to the optical deflector 100. It is guided as mixed light to the reflecting surface (mirror). The mixed light is deflected by the mirror of the optical deflector 100, folded back by the scanning mirror 1903, and draws 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 luminous flux emitted from the screen 1904 is magnified and displayed as a virtual image I through a single concave mirror 1906 and a 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 becomes convex upward or downward due to the influence of the windshield 1905. In addition, a configuration having a separate partial reflector (combiner) having the same function (partial reflection) as the windshield 1905 may be used. The head-up display 1901 enables high-brightness image projection in any limited direction while maintaining high image quality. For example, navigation information (information such as speed and mileage) for driving a car can be obtained. , It can be displayed with high brightness in order to improve visibility. If it is a device that projects an image by performing optical scanning using an optical scanning device 1902, for example, a projector that projects an image on a display screen, a mounting member mounted on an observer's head, or the like has reflection transmission. The same can be applied to a head-mounted display or the like that projects an image on a screen of a member or the like.

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

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

Japanese Unexamined Patent Publication No. 2017-138375

Claims (8)

It has an optical deflector and a control unit that controls the drive of the optical deflector.
The light deflector is
A mirror portion having a mirror surface, a cantilever in the shape of a mianda that rotatably supports the mirror portion, and a cantilever.
The first piezoelectric member and the second piezoelectric member that generate the warp deformation of the cantilever,
The common wiring connected to the first piezoelectric member and the electrode on one end side of the second piezoelectric member, and
Have,
The control unit
The first drive voltage applied to the first piezoelectric member and the second drive voltage to apply the second piezoelectric member change stepwise in predetermined time increments.
The timing of changing the first drive voltage applied to the first piezoelectric member in the predetermined time increments and the timing of changing the second drive voltage of applying the second piezoelectric member in the predetermined time increments are relative to each other. Misaligned,
An optical scanning device characterized by this. The optical scanning apparatus according to claim 1, wherein the drive voltage waveform of the first drive voltage and the drive voltage waveform of the second drive voltage overlap in 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 with respect to the timing for changing the first drive voltage is
The optical scanning apparatus according to claim 1 or 2, wherein when the first drive voltage is changed, the current value flowing through the common wiring is set to be at least a time during which the current value flows to half or less of the peak value. Claim 1 is characterized in that the timing for changing the second drive voltage with respect to the timing for changing the first drive voltage is half of the time interval for changing the first drive voltage in predetermined time intervals. Or the optical scanning apparatus according to 2. The light deflector is
It has a cantilever component that rotates the mirror portion around a rotation axis in a direction different from the rotation axis in which the mirror portion is rotatably supported by the cantilever having a meander shape.
The optical scanning apparatus according to any one of claims 1 to 4. The cantilever in the shape of a mianda is
The first piezoelectric member and the second piezoelectric member are alternately held every other beam of the cantilever.
The optical scanning apparatus according to claim 5. The optical scanning apparatus according to any one of claims 1 to 6.
A display device that displays the light emitted from the optical scanning device as an image, and
An image display device comprising. The optical scanning apparatus according to any one of claims 1 to 6.
A display device that displays the light emitted from the optical scanning device as an image, and
A moving body including a moving means for moving while displaying the image.

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