Optical path control device, display device, and optical path control method

Abstract

To provide an optical path control device, a display device and an optical path control method, in which the power consumption of an actuator is reduced and the control of the actuator is simplified.SOLUTION: The optical path control device comprises a swing unit having an optical unit which light enters, an actuator for causing the swing unit to swing around a swing shaft, and a drive unit for applying a drive signal of current value to the actuator. The drive unit applies a current value that is 1 / 2 the peak current value in a period which is 1 / 2 the cycle of natural vibration of the swing unit and, thereafter, maintains the same at the peak current value or a zero current value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical path control device, a display device, and an optical path control method. [Background technology]

[0002] There is known an optical device that shifts the optical axis by swinging the optical unit into which light is incident. For example, Patent Document 1 listed below describes a technology that can increase the resolution of a projected image compared to the resolution of a light modulation device by swinging the optical unit to shift the optical path of light passing through the optical unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-091343 Summary of the Invention [Problem to be solved by the invention]

[0004] Optical devices are known that shift the optical path of light passing through an optical unit by swinging the optical unit around intersecting first and second axes. Such optical devices have a first actuator that swings the optical unit around the first axis and a second actuator that swings the optical unit around the second axis. Driving the two actuators simultaneously tilts the optical unit by a predetermined angle in a predetermined direction, thereby changing the optical path. Driving two actuators simultaneously increases power consumption. Furthermore, this requires balancing the drive amounts of the two actuators, i.e., the respective displacement amounts required to tilt the optical unit, which complicates the adjustment and control of each actuator.

[0005] In view of the above problems, an object of the present invention is to provide a light path control device, a display device, and a light path control method that reduce the power consumption of an actuator and simplify the control of the actuator. [Means for solving the problem]

[0006] An optical path control device according to one embodiment of the present invention comprises an oscillating unit having an optical unit into which light is incident, an actuator that oscillates the oscillating unit, and a drive unit that applies a drive signal of a current value to the actuator, wherein the drive unit applies a current value that is half the peak current value for a period that is half the period of the natural vibration of the oscillating unit, and then maintains the current value at the peak current value or at 0.

[0007] A display device according to one aspect of the present invention includes the light path control device and an irradiation device that irradiates the optical section with light.

[0008] An optical path control method according to one aspect of the present invention is an optical path control method that controls an optical path by applying a drive signal to an actuator that oscillates an oscillating part having an optical part into which light is incident, and after applying a current value that is half the peak current value to the actuator at a period that is half the period of the natural frequency of the oscillating part, the current value is maintained at the peak current value or at a current value of 0. [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce the power consumption of the actuator and simplify the control of the actuator. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating a display device according to this embodiment. [Figure 2] FIG. 2 is a block diagram schematically illustrating the circuit configuration of the display device. [Figure 3] FIG. 3 is a plan view showing the optical path control mechanism. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV of FIG. [Figure 6]FIG. 6 is a graph illustrating the waveform of the drive signal of the drive unit. [Figure 7] FIG. 7 is a graph illustrating the oscillation pattern of the optical part. [Figure 8] FIG. 8 is an explanatory diagram illustrating a two-axis swing pattern of the optical part. [Figure 9] FIG. 9 is a graph illustrating the relationship between the waveform of the drive signal of the drive unit and the oscillation pattern of the optical unit. [Figure 10] FIG. 10 is a schematic diagram illustrating power consumption in a trapezoidal wave drive signal. [Figure 11] FIG. 11 is a schematic diagram illustrating power consumption in a step wave of a drive signal. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0012] First Embodiment [Outline of display device configuration] FIG. 1 is a schematic diagram of a display device according to a first embodiment.

[0013] In the first embodiment, as shown in FIG. 1 , the display device 1 has a light path control device 10 and an irradiation device 100. The irradiation device 100 is a device that irradiates light L for an image. The light path control device 10 is a device that controls the optical path of the light L. The light path control device 10 shifts the optical axis of the light L to shift the position of the image displayed by the light L, thereby increasing the resolution of the projected image compared to the resolution of the image generated by the irradiation device 100 (i.e., the number of pixels of a display element 106, which will be described later).

[0014] The irradiation device 100 includes a light source 101, polarizing plates 105R, 105G, and 105B, display elements 106R, 106G, and 106B, polarizing plates 107R, 107G, and 107B, a color synthesis prism 108, a projection lens 109, dichroic mirrors 120 and 121, reflecting mirrors 130 and 131, lenses 140, 141, 142, 143, 144, and 145, a polarization conversion element 150, and a video signal processing circuit 160. When the display elements 106R, 106G, and 106B are not to be distinguished from one another, they will be referred to as display elements 106.

[0015] The light source 101 is a light source that generates and irradiates light. The light source 101 irradiates incident light L0. In the following description, an example will be described in which one light source 101 is used as the light source that irradiates the incident light L0, but other optical devices may be included to generate the incident light L0.

[0016] Incident light L0 from light source 101 is incident on lens 140. Lenses 140 and 141 are, for example, fly's eye lenses. The illumination distribution of the incident light L0 is homogenized by lenses 140 and 141, and the incident light is incident on polarization conversion element 150. Polarization conversion element 150 is an element that aligns the polarization of the incident light L0, and includes, for example, a polarizing beam splitter and a retardation plate. The polarization conversion element 150 aligns the incident light L0 to p-polarized light, for example.

[0017] The incident light L0, the polarization of which has been aligned by the polarization conversion element 150, is irradiated onto the dichroic mirror 120 via the lens 142. The lens 142 is, for example, a condenser lens.

[0018] The dichroic mirror 120 separates the incident light L0 into yellow light LRG and blue light LB containing a blue band component. The yellow illumination light LRG separated by the dichroic mirror 120 is reflected by the reflecting mirror 130 and enters the dichroic mirror 121.

[0019] The dichroic mirror 121 separates the incident yellow light LRG into red light LR containing a component in the red wavelength range and green light LG containing a component in the green wavelength range.

[0020] The red light LR separated by the dichroic mirror 121 is irradiated onto the polarizing plate 105R via the lens 143. The green light LG separated by the dichroic mirror 121 is irradiated onto the polarizing plate 105G via the lens 144. The blue light LB separated by the dichroic mirror 120 is reflected by the reflecting mirror 131 and irradiated onto the polarizing plate 105B via the lens 145.

[0021] The polarizing plates 105R, 105G, and 105B have the property of reflecting either s-polarized light or p-polarized light and transmitting the other. For example, the polarizing plates 105R, 105G, and 105B reflect s-polarized light and transmit p-polarized light. The polarizing plates 105R, 105G, and 105B are also called reflective polarizing plates.

[0022] The p-polarized red light LR is transmitted through polarizer 105R and is irradiated onto display element 106R. The p-polarized green light LG is transmitted through polarizer 105G and is irradiated onto display element 106G. The p-polarized blue light LB is transmitted through polarizer 105B and is irradiated onto display element 106B.

[0023] Display elements 106R, 106G, and 106B are, for example, reflective liquid crystal display elements. In the following description, a case where display elements 106R, 106G, and 106B are reflective liquid crystal display elements will be described as an example, but they are not limited to reflective types and may also be configured to use transmissive liquid crystal display elements. Various applications are also possible for configurations that use other display elements instead of liquid crystal display elements.

[0024] The display element 106R is controlled by the video signal processing circuit 160. The video signal processing circuit 160 drives and controls the display element 106R based on image data for the red component. The display element 106R optically modulates p-polarized red light LR in accordance with the control of the video signal processing circuit 160 to generate s-polarized red light LR. The display element 106G is controlled by the video signal processing circuit 160. The video signal processing circuit 160 drives and controls the display element 106G in accordance with image data for the green component. The display element 106G optically modulates p-polarized green light LG in accordance with the control of the video signal processing circuit 160 to generate s-polarized green light LG. The display element 106B is controlled by the video signal processing circuit 160. The video signal processing circuit 160 drives and controls the display element 106B in accordance with image data for the blue component. Display element 106B optically modulates p-polarized blue light LB based on image data of the blue component under the control of video signal processing circuit 160, and generates s-polarized blue light LB.

[0025] The polarizing plates 107R, 107G, and 107B have the property of transmitting either s-polarized light or p-polarized light and reflecting or absorbing the other. For example, the polarizing plates 107R, 107G, and 107B transmit s-polarized light and absorb unwanted p-polarized light.

[0026] S-polarized red light LR generated by display element 106R is reflected by polarizing plate 105R, passes through polarizing plate 107R, and is irradiated onto color synthesis prism 108. S-polarized green light LG generated by display element 106G is reflected by polarizing plate 105G, passes through polarizing plate 107G, and is irradiated onto color synthesis prism 108. S-polarized blue light LB generated by display element 106B is reflected by polarizing plate 105B, passes through polarizing plate 107B, and is irradiated onto color synthesis prism 108.

[0027] The color synthesis prism 108 synthesizes the incident red light LR, green light LG, and blue light LB, and irradiates the resulting light L for image display onto a projection lens 109. The light L is projected via the projection lens 109 onto a screen or the like (not shown).

[0028] Although the irradiation device 100 has the above-described configuration, the configuration is not limited to the above description and may have any configuration.

[0029] The light path control device 10 has a light path control mechanism 12, a control circuit (controller) 14, and a drive circuit (driver) 16. The light path control mechanism 12 is a mechanism that oscillates when driven by the drive circuit 16. The light path control mechanism 12 is provided between the color synthesis prism 108 and the projection lens 109 in a direction along the optical path of the light L. The light path control mechanism 12 oscillates while receiving the light L from the color synthesis prism 108, thereby shifting the traveling direction (optical path) of the light L and outputting it toward the projection lens 109. In this way, the light path control device 10 controls the optical path of the light L so that the optical path of the light L is shifted. The position at which the light path control mechanism 12 is provided is not limited to between the color synthesis prism 108 and the projection lens 109, and may be any position.

[0030] [Display device functional configuration] FIG. 2 is a block diagram schematically showing the circuit configuration of the display device.

[0031] As shown in FIG. 2, the video signal processing circuit 160 controls the display elements 106R, 106B, and 106G. The video signal processing circuit 160 receives image data for controlling the display elements 106R, 106B, and 106G, and a video signal including a synchronization signal. The video signal processing circuit 160 controls the display elements 106R, 106B, and 106G based on the image data while synchronizing the timing based on the synchronization signal. The control circuit 14 includes a digital circuit 14A. The synchronization signal from the video signal processing circuit 160 is input to the digital circuit 14A. The digital circuit 14A generates a digital drive signal for driving the optical path control mechanism 12 while synchronizing the timing based on the synchronization signal. The drive circuit 16 receives the digital drive signal generated by the digital circuit 14A, amplifies the digital drive signal, and outputs it to an actuator 12B of the optical path control mechanism 12, which will be described later. The actuator 12B is driven in response to a drive signal to swing a swinging portion 12A (see FIG. 3) which will be described later.

[0032] [Optical path control mechanism] 3 is a plan view showing the optical path control mechanism, FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a cross-sectional view taken along line VV in FIG.

[0033] As shown in FIGS. 3 to 5, the light path control mechanism 12 has a swinging part 12A including an optical member (optical part) 20 onto which light L is incident, and an actuator 12B that swings the swinging part 12A.

[0034] The actuator 12B oscillates the oscillating unit 12A about a first oscillation axis AX and a second oscillation axis BX that extend along two directions that intersect (preferably, are perpendicular to) the direction in which light L is incident on the optical member 20. The first oscillation axis AX and the second oscillation axis BX are preferably perpendicular to each other. Therefore, the optical path control mechanism 12 includes a first oscillation unit 21 and a second oscillation unit 22 as the oscillating unit 12A, a first shaft unit 23 and a second shaft unit 24 that extend along the first oscillation axis AX and the second oscillation axis BX, a first actuator 25 and a second actuator 26 as the actuator 12B, and a support unit 27.

[0035] In FIG. 3, the AY direction is the horizontal arrangement direction of pixels of the optical member 20, and the BY direction is the vertical arrangement direction of pixels of the optical member 20. The AY direction and the BY direction intersect perpendicularly. The first oscillation axis AX direction and the second oscillation axis BX direction have the same center O and intersect at an angle of 45 degrees with the AY direction and the BY direction. The first oscillation axis AX direction is offset by 45 degrees counterclockwise from the AY direction, and the second oscillation axis BX direction is offset by 45 degrees counterclockwise from the BY direction. In other words, the first oscillation axis AX direction and the second oscillation axis BX direction are offset by 45 degrees with respect to the horizontal and vertical arrangement directions of pixels.

[0036] The optical member 20 is a member that transmits incident light L. The light L is incident on one surface of the optical member 20, the optical member 20 transmits the incident light L, and the light L is emitted from the other surface. The optical member 20 is a glass plate, but the material and shape may be arbitrary.

[0037] The first oscillating part 21 has an optical member 20 and a first movable part 31. The first movable part 31 is a member that supports the optical member 20. The first movable part 31 is fixed to the optical member 20. Specifically, the first movable part 31 is a frame-shaped member made of a plate material with a through-hole 31a formed in the center. The optical member 20 is fixed to the first movable part 31 in a state where it is fitted into the through-hole 31a of the first movable part 31. Note that the optical member 20 is fixed to the first movable part 31 via a fixing member or adhesive for fixing it to the first movable part 31, but the method of fixing the optical member 20 to the first movable part 31 may be arbitrary.

[0038] The second oscillating part 22 is disposed outside the first oscillating part 21. The second oscillating part 22 has a second movable part 32. The second movable part 32 is a member that supports the first movable part 31. The first movable part 31 is supported by the second movable part 32 so as to be able to oscillate freely around a first oscillation axis AX. Specifically, the second movable part 32 is a frame-shaped member made of a plate material with a through hole 32a formed in its center. The first movable part 31 is supported by the second movable part 32 so as to be able to oscillate freely in the through hole 32a of the second movable part 32 with a predetermined gap between them. The first movable part 31 and the second movable part 32 are connected by a pair of first shaft parts 23 that are aligned along the first oscillation axis AX. The first movable part 31 oscillates around the first oscillation axis AX as the pair of first shaft parts 23 elastically deform so as to be twisted relative to the second movable part 32.

[0039] The support part 27 is disposed outside the second oscillation part 22. The support part 27 is a member that supports the second movable part 32. The second movable part 32 is supported by the support part 27 so as to be able to oscillate freely around the second oscillation axis BX. Specifically, the support part 27 is a frame-shaped member made of a plate material with a through hole 27a formed in the center. The second movable part 32 is supported by the support part 27 so as to be able to oscillate freely, with the second movable part 32 being disposed in the through hole 27a of the support part 27 with a predetermined gap therebetween. The second movable part 32 and the support part 27 are connected by a pair of second shaft parts 24 that extend along the second oscillation axis BX. The second movable part 32 oscillates around the second oscillation axis BX as the pair of second shaft parts 24 elastically deform so as to be twisted relative to the support part 27.

[0040] The second movable part 32 (second oscillating part 22) oscillates around the second oscillation axis BX with respect to the support part 27, with the pair of second shaft parts 24 as fulcrums. The first movable part 31 (first oscillating part 21) oscillates around the first oscillation axis AX with respect to the second movable part 32, with the pair of first shaft parts 23 as fulcrums. Therefore, the optical element 20 fixed to the first movable part 31 can oscillate around the first oscillation axis AX and the second oscillation axis BX. When the optical element 20 oscillates around the first oscillation axis AX and the second oscillation axis BX, the posture of the optical element 20 changes, and the optical path of the light L passing through the optical element 20 can be shifted.

[0041] In this embodiment, the first movable part 31, the second movable part 32, the first shaft part 23, and the second shaft part 24 are integrally formed. Therefore, the first movable part 31 oscillates relative to the second movable part 32 as the first shaft part 23 elastically deforms so as to be twisted in the circumferential direction. However, the first movable part 31, the second movable part 32, and the first shaft part 23 may be formed separately and then connected. Also, one end and the other end of the second movable part 32 in the axial direction of the second oscillation axis BX are fixed so as to be connected to the support part 27, and the second shaft parts 24 are formed at each end of the second movable part 32. However, the second shaft parts 24 may be provided at each end of the second movable part 32, and each second shaft part 24 may be fixed so as to be directly connected to the support part 27. Furthermore, the second movable part 32, the second shaft part 24, and the support part 27 may be formed integrally.

[0042] The first actuator 25 swings the first movable part 31 (first swing part 21) about the first swing axis AX with respect to the support part 27, using the pair of first shaft parts 23 as fulcrums. The first actuators 25 are disposed on both sides of the first swing axis AX in the radial direction (axial direction of the second swing axis BX). The first actuator 25 has a coil 41, a yoke 42, and a magnet 43.

[0043] The coil 41 is attached to the first movable part 31 and fixed to a coil attachment part 31b provided on the first movable part 31. The coils 41 are provided at both ends of the first movable part 31 in the radial direction of the first oscillation axis AX (one side and the other side in the axial direction of the second oscillation axis BX). The yoke 42 is a member that forms a magnetic path. The yoke 42 is attached to the support part 27 and fixed relative to the support part 27. The yokes 42 are arranged at both ends of the first movable part 31 corresponding to the coils 41. The magnets 43 are permanent magnets. The magnets 43 are attached to the yoke 42 and fixed relative to the yoke 42. The magnets 43 are arranged in positions adjacent to the respective coils 41.

[0044] A drive signal is input to the coil 41 from the drive circuit 16 (see FIG. 2). In the example shown in FIG. 5, a magnet 43 is attached to one side of a U-shaped yoke 42, and an air gap is formed between the unattached surface of the magnet 43 and the opposing U-shaped surface of the yoke 42. The coil 41 is disposed within the air gap. When a drive signal is input to the coil 41, a current flows through the coil 41, which is a conductor located within the air gap (magnetic field) formed by the magnet 43 and the yoke 42, generating a force in the coil 41. This force causes the first movable part 31 (first oscillating part 21) fixed to the coil 41 to oscillate. In other words, the first actuator 25 can be said to be an electromagnetic actuator composed of the coil 41, the yoke 42, and the magnet 43.

[0045] The second actuator 26 oscillates the second movable part 32 (second oscillating part 22) about the second oscillating axis BX with respect to the support part 27, with the pair of second shaft parts 24 as fulcrums. The second actuators 26 are disposed on both sides of the second oscillating axis BX in the radial direction (axial direction of the first oscillating axis AX). The second actuator 26 has a coil 44, a yoke 45, and a magnet 46.

[0046] The coil 44 is attached to the second movable part 32 and fixed to a coil attachment part 32b provided on the second movable part 32. The coils 44 are respectively provided at both ends of the second movable part 32 in the radial direction of the second oscillation axis BX (one side and the other side in the axial direction of the first oscillation axis AX). The yoke 45 is a member that forms a magnetic path. The yoke 45 is attached to the support part 27 and fixed relative to the support part 27. The yokes 45 are respectively arranged at both ends of the second movable part 32 corresponding to the coils 44. The magnets 46 are permanent magnets. The magnets 46 are attached to the yoke 45 and fixed relative to the yoke 45. The magnets 46 are arranged in positions adjacent to the respective coils 44.

[0047] A drive signal is input to the coil 44 from the drive circuit 16 (see FIG. 2). In the example shown in FIG. 4, a magnet 46 is attached to one side of a U-shaped yoke 45, and an air gap is formed between the unattached surface of the magnet 46 and the opposing U-shaped surface of the yoke 45. The coil 44 is disposed within the air gap. When a drive signal is input to the coil 44, a current flows through the coil 44, which is a conductor located within the air gap (magnetic field) formed by the magnet 46 and the yoke 45, generating a force in the coil 44. This force causes the second movable part 32 (second oscillating part 22) fixed to the coil 44 to oscillate. In other words, the second actuator 26 can be said to be an electromagnetic actuator composed of the coil 44, the yoke 45, and the magnet 46.

[0048] In the optical path control mechanism 12, the first movable part 31 on which the optical member 20 is provided oscillates, and the second movable part 32 supporting the first movable part 31 oscillates as well. Therefore, it can be said that the optical member 20, the first movable part 31, the second movable part 32, and the coils 41 and 44 constitute the oscillating part 12A. In other words, it can be said that the part of the optical path control mechanism 12 that oscillates relative to the support part 27 corresponds to the oscillating part 12A. Note that the first shaft part 23 also oscillates together with the second movable part 32, and is therefore included in the oscillating part 12A. Furthermore, if a fixing member or adhesive for fixing the optical member 20 to the first movable part 31, or a substrate or lead wire for passing current through the coils 41 and 44, is provided, these also oscillate relative to the support part 27 and are therefore included in the oscillating part 12A.

[0049] In this embodiment, the first movable part 31 is oscillated by the first actuator 25, and the second movable part 32 is oscillated by the second actuator 26. In this case, the yokes 42 and 45 constituting the actuators 25 and 26 are fixed to the support part 27. Therefore, when the second movable part 32 is oscillated by the second actuator 26, a gap is secured between the first actuator 25 and the second movable part 32 so that they do not interfere with each other.

[0050] Although the actuators 25, 26 are of a so-called moving coil type in which the coils 41, 44 are arranged on the movable parts 31, 32, the present invention is not limited to this and may be of a so-called moving magnet type in which the magnets 43, 46 are arranged on the movable parts 31, 32 and the coils 41, 44 are arranged on the support part 27. In this case, the magnets 43, 46 are swung together with the optical member 20, and therefore the magnets 43, 46 are included in the swiveling part 12A instead of the coils 41, 44.

[0051] The optical path control mechanism 12 has the above-described configuration, but is not limited to this and may have any configuration in which the optical part can shift the optical path of light L by oscillating the optical part using an actuator to which a drive signal is applied.

[0052] [Drive signal] Here, we will explain the drive signal applied from drive circuit 16 to actuator 12B. Figure 6 is a graph illustrating the waveform of the drive signal of the drive unit. T1 is one frame period of the input video signal, and by displaying one frame in four sub-frames, the resolution of the projected image can be made higher than the resolution of the light modulation device. For example, if one frame period is 60 Hz, the first sub-frame period is 1 / 240 seconds, and the same applies to the second, third, and fourth sub-frames. In Figure 6, the waveform of the drive signal applied to first actuator 25 is represented by a solid line, and the waveform of the drive signal applied to second actuator 26 is represented by a dotted line.

[0053] As shown in FIG. 6, the digital drive signal applied from the drive circuit 16 to the first actuator 25 is an electrical signal whose current value changes over time. Hereinafter, the waveform representing the change in the current value of the drive signal over time is referred to as the drive signal waveform. Here, the current value varies between a first current value A1 and a fourth current value A4, with a current value A0 at the midpoint between the first current value A1 and the fourth current value A4 being zero. The first current value A1 and the fourth current value A4 are opposite in sign and may have the same absolute value. In FIG. 6, the first current value A1 and the second current value A2 are negative, and the third current value A3 and the fourth current value A4 are positive. In this embodiment, the digital circuit 14A and the like include digital switching circuits, so the supply of current to the first actuator 25 and the second actuator 26 can be stopped, and the current value A0 is maintained during the period during which the current supply is stopped.

[0054] The waveform of the drive signal applied to the first actuator 25 is shown by a solid line in FIG. 6. The same waveform of the drive signal is repeated every cycle T1. The cycle T1 includes periods T1A, T1B, T1C, and T1D. Periods T1A, T1B, T1C, and T1D are continuous over time. Period T1A corresponds to the period during which the first oscillator 21 is displaced from the reference angle D0 to the second angle D2 and the period during which the first oscillator 21 is held at the second angle D2. With respect to the optical axis of light L, this corresponds to the period during which the optical axis is displaced from the D operating position to the A operating position and the period during which an image (an image shifted by 1 / 4 pixel to one side in the direction of the second oscillator axis BX) is displayed when the optical axis is at the A operating position. Period T1C corresponds to the period during which the first oscillator 21 is displaced from the reference angle D0 to the first angle D1 and the period during which the first oscillator 21 is held at the first angle D1. With respect to the optical axis of light L, period T1B corresponds to the period during which the first oscillation unit 21 is displaced from operating position B to operating position C and the period during which an image when the first oscillation unit 21 is at operating position C (an image shifted by 1 / 4 pixel in the other direction along the second oscillation axis BX) is displayed. Period T1B corresponds to the period during which the first oscillation unit 21 is displaced from the second angle D2 to the reference angle D0 and the period during which the first oscillation unit 21 is held at the reference angle D0, and period T1D corresponds to the period during which the first oscillation unit 21 is displaced from the first angle D1 to the reference angle D0 and the period during which the first oscillation unit 21 is held at the reference angle D0.

[0055] The period T1A includes a first period T1A-1 and a second period T1A-2. First, at the start of the first period T1A-1, the current value of the drive signal switches from current value A0 to a third current value A3 and is maintained at the third current value A3 until the end of the first period T1A-1. As a result, the displacement angle of the first oscillation unit 21 changes from the reference angle D0 to the second angle D2 during the first period T1A-1. Next, at the start of the second period T1A-2, the current value of the drive signal switches from the third current value A3 to a fourth current value A4 and is maintained at the fourth current value A4 until the end of the second period T1A-2. As a result, the displacement angle of the first oscillation unit 21 is maintained at the second angle D2 during the second period T1A-2. The length of the first period T1A-1 has a value corresponding to the natural frequency of the first oscillation part 21.

[0056] Period T1B includes a first period T1B-1 and a second period T1B-2. First, at the start of the first period T1B-1, the current value of the drive signal switches from the fourth current value A4 to the third current value A3 and is maintained at the third current value A3 until the end of the first period T1B-1. As a result, the displacement angle of the first oscillation unit 21 changes from the second angle D2 to the reference angle D0 and returns to the reference angle D0 during the first period T1B-1. Next, at the start of the second period T1B-2, the current value of the drive signal switches from the third current value A3 to the current value A0 and is maintained at the current value A0 until the end of the second period T1B-2. As a result, the displacement angle of the first oscillation unit 21 is maintained at the reference angle D0 during the second period T1B-2. The length of the first period T1B-1 has a value corresponding to the natural frequency of the first oscillation part 21.

[0057] The first oscillator 21 refers to the part of the optical path control mechanism 12 that oscillates relative to the second oscillator 22 (in this embodiment, the optical member 20, the first movable part 31, and the coil 41). That is, the length of the first period T1A-1 and the length of the first period T1B-1 can be said to have values that correspond to the natural frequency of the part that oscillates relative to the second oscillator 22. More specifically, the length of the first period T1A-1 and the length of the first period T1B-1 each preferably have a value that is approximately the same as 1 / 2 the natural period, which is the reciprocal of the natural frequency of the first oscillator 21, and more preferably have a value that is the same as 1 / 2 the natural period.

[0058] The period T1C includes a first period T1C-1 and a second period T1C-2. First, at the start of the first period T1C-1, the current value of the drive signal switches from current value A0 to a second current value A2 and is maintained at the second current value A2 until the end of the first period T1C-1. As a result, the displacement angle of the first oscillating unit 21 changes from the reference angle D0 to the first angle D1 during the first period T1C-1. Next, at the start of the second period T1C-2, the current value of the drive signal switches from the second current value A2 to the first current value A1 and is maintained at the first current value A1 until the end of the second period T1C-2. As a result, the displacement angle of the first oscillating unit 21 is maintained at the first angle D1 during the second period T1C-2. The length of the first period T1C-1 has a value corresponding to the natural frequency of the first oscillation part 21.

[0059] The period T1D includes a first period T1D-1 and a second period T1D-2. First, at the start of the first period T1D-1, the current value of the drive signal switches from a first current value A1 to a second current value A2 and is maintained at the second current value A2 until the end of the first period T1D-1. As a result, the displacement angle of the first oscillating unit 21 changes from the first angle D1 to the reference angle D0 and returns to the reference angle D0 during the first period T1D-1. Next, at the start of the second period T1D-2, the current value of the drive signal switches from the second current value A2 to a current value A0 and is maintained at the current value A0 until the end of the second period T1D-2. As a result, the displacement angle of the first oscillating unit 21 is maintained at the reference angle D0 during the second period T1D-2. The length of the first period T1D-1 corresponds to the natural frequency of the first oscillating unit 21.

[0060] The first oscillator 21 refers to the portion of the optical path control mechanism 12 that oscillates relative to the second oscillator 22 (in this embodiment, the optical member 20, the first movable portion 31, and the coil 41). That is, the length of the first period T1C-1 and the length of the first period T1D-1 have values that correspond to the natural frequency of the portion that oscillates relative to the second oscillator 22. More specifically, the length of the first period T1C-1 and the length of the first period T1D-1 each preferably have a value that is approximately the same as 1 / 2 the natural period, which is the reciprocal of the natural frequency of the first oscillator 21, and more preferably have a value that is the same as 1 / 2 the natural period.

[0061] On the other hand, the waveform of the drive signal applied to the second actuator 26 is indicated by a dotted line in FIG. 6. The same waveform of the drive signal is repeated every cycle T2. The cycle T2 includes periods T2A, T2B, T2C, and T2D. Periods T2A, T2B, T2C, and T2D are continuous over time. Period T2A corresponds to the period during which the second oscillator 22 is displaced from the reference angle D0 to the second angle D2 and the period during which the second oscillator 22 is maintained at the second angle D2. With respect to the optical axis of light L, period T2A corresponds to the period during which the second oscillator 22 is displaced from the A operating position to the B operating position and the period during which an image (an image shifted by 1 / 4 pixel to one side in the direction of the first oscillation axis AX) is displayed when the second oscillator 22 is at the B operating position. Period T1D corresponds to the period during which the second oscillator 22 is displaced from the reference angle D0 to the first angle D1 and the period during which the second oscillator 22 is maintained at the first angle D1. With respect to the optical axis of light L, these periods correspond to the period during which the second oscillation part 22 is displaced from the second angle D2 to the reference angle D0 and the period during which the second oscillation part 22 is held at the reference angle D0. Period T2D corresponds to the period during which the second oscillation part 22 is displaced from the first angle D1 to the reference angle D0 and the period during which the second oscillation part 22 is held at the reference angle D0.

[0062] The period T2A includes a first period T2A-1 and a second period T2A-2. First, at the start of the first period T2A-1, the current value of the drive signal switches from current value A0 to a third current value A3 and is maintained at the third current value A3 until the end of the first period T2A-1. As a result, the displacement angle of the second oscillation unit 22 changes from the reference angle D0 to the second angle D2 during the first period T2A-1. Next, at the start of the second period T2A-2, the current value of the drive signal switches from the third current value A3 to a fourth current value A4 and is maintained at the fourth current value A4 until the end of the second period T2A-2. As a result, the displacement angle of the second oscillation unit 22 is maintained at the second angle D2 during the second period T2A-2. The length of the first period T2A-1 has a value corresponding to the natural frequency of the second oscillation part 22.

[0063] The period T2B includes a first period T2B-1 and a second period T2B-2. First, at the start of the first period T2B-1, the current value of the drive signal switches from the fourth current value A4 to the third current value A3 and is maintained at the third current value A3 until the end of the first period T2B-1. As a result, the displacement angle of the second oscillator 22 changes from the second angle D2 to the reference angle D0 and returns to the first period T2B-1. Next, at the start of the second period T2B-2, the current value of the drive signal switches from the third current value A3 to the current value A0 and is maintained at the current value A0 until the end of the second period T2B-2. As a result, the second oscillator 22 is maintained at the reference angle D0 during the second period T2B-2. The length of the first period T2B-1 corresponds to the natural frequency of the second oscillator 22.

[0064] The second oscillating part 22 refers to the part of the optical path control mechanism 12 that oscillates relative to the support part 27 (in this embodiment, the optical member 20, the second movable part 32, and the coil 44). In other words, the length of the first period T2A-1 and the length of the first period T2B-1 have values that correspond to the natural frequency of the part that oscillates relative to the support part 27. More specifically, the length of the first period T2A-1 and the length of the first period T2B-1 each preferably have a value that is approximately the same as 1 / 2 the natural period, which is the reciprocal of the natural frequency of the second oscillating part 22, and more preferably have a value that is the same as 1 / 2 the natural period.

[0065] The period T2C includes a first period T2C-1 and a second period T2C-2. First, at the start of the first period T2C-1, the current value of the drive signal switches from current value A0 to second current value A2 and is maintained at the second current value A2 until the end of the first period T2C-1. As a result, the displacement angle of the second oscillation unit 22 changes from the reference angle D0 to the first angle D1 during the first period T2C-1. Next, at the start of the second period T2C-2, the current value of the drive signal switches from the second current value A2 to the first current value A1 and is maintained at the first current value A1 until the end of the second period T2C-2. As a result, the displacement angle of the second oscillation unit 22 is maintained at the first angle D1 during the second period T2C-2. The length of the first period T2C-1 has a value corresponding to the natural frequency of the second oscillation part 22.

[0066] The period T2D includes a first period T2D-1 and a second period T2D-2. First, at the start of the first period T2D-1, the current value of the drive signal switches from the first current value A1 to the second current value A2 and is maintained at the second current value A2 until the end of the first period T2D-1. As a result, the displacement angle of the second oscillating part 22 changes from the first angle D1 to the reference angle D0 and returns to the first period T2D-1. Next, at the start of the second period T2D-2, the current value of the drive signal switches from the second current value A2 to the current value A0 and is maintained at the current value A0 until the end of the second period T2D-2. As a result, the second oscillating part 22 is maintained at the reference angle D0 during the second period T2D-2. The length of the first period T2D-1 corresponds to the natural frequency of the second oscillating part 22.

[0067] The second oscillating part 22 refers to the part of the optical path control mechanism 12 that oscillates with respect to the support part 27 (in this embodiment, the optical member 20, the second movable part 32, and the coil 44). In other words, the length of the first period T2C-1 and the length of the first period T2D-1 have values that correspond to the natural frequency of the part that oscillates with respect to the support part 27. More specifically, the length of the first period T2C-1 and the length of the first period T2D-1 each preferably have a value that is approximately the same as 1 / 2 the natural period, which is the reciprocal of the natural frequency of the second oscillating part 22, and more preferably have a value that is the same as 1 / 2 the natural period.

[0068] The waveform of the drive signal applied to the first actuator 25 (solid line in FIG. 6) and the waveform of the drive signal applied to the second actuator 26 (dotted line in FIG. 6) are shifted by a predetermined period T12. For example, the start timing of a first period T1A-1 of the waveform of the drive signal applied to the first actuator 25 and the start timing of a first period T2A-1 of the waveform of the drive signal applied to the second actuator 26 are shifted by the predetermined period T12. Therefore, the second period T1A-2 in which the current value in the waveform of the drive signal applied to the first actuator 25 is held at the fourth current value A4 becomes a second period T2D-2 in which the current value in the waveform of the drive signal applied to the second actuator 26 is held at the current value A0 (current value 0). Similarly, the second period T1C-2 in which the current value in the waveform of the drive signal applied to the first actuator 25 is maintained at the first current value A1 is the second period T2D-2 in which the current value in the waveform of the drive signal applied to the second actuator 26 is maintained at the current value A0 (current value 0).

[0069] Furthermore, a second period T2A-2 in which the current value in the waveform of the drive signal applied to the second actuator 26 is held at the fourth current value A4 becomes a second period T2B-2 in which the current value in the waveform of the drive signal applied to the first actuator 25 is held at the current value A0 (current value 0). Similarly, a second period T2C-2 in which the current value in the waveform of the drive signal applied to the second actuator 26 is held at the first current value A1 becomes a second period T2D-2 period T1D in which the current value in the waveform of the drive signal applied to the first actuator 25 is held at the current value A0 (current value 0).

[0070] [Oscillation pattern] Next, the oscillation patterns of the first oscillation unit 21 and the second oscillation unit 22 due to the application of the drive signal will be described. Fig. 7 is a graph illustrating the oscillation patterns of the optical unit. In Fig. 7, the oscillation pattern of the first oscillation unit 21 is represented by a solid line, and the oscillation pattern of the second oscillation unit 22 is represented by a dotted line.

[0071] 7, the oscillation pattern (solid line) of the first oscillating part 21 refers to the displacement angle (angle about the first oscillation axis AX) of the first oscillating part 21 per unit time when a drive signal is applied to the first actuator 25. The oscillation pattern (dotted line) of the second oscillating part 22 refers to the displacement angle (angle about the second oscillation axis BX) of the second oscillating part 22 per unit time when a drive signal is applied to the second actuator 26.

[0072] 9, in the first oscillation unit 21, the current value of the drive signal switches from current value A0 to third current value A3 during the first period T1A-1 and is maintained at the third current value A3 until the end of the first period T1A-1. As a result, the displacement angle of the first oscillation unit 21 changes from the reference angle D0 to the second angle D2 during the first period T1A-1.

[0073] During the second period T1A-2, the drive signal maintains a current value at a fourth current value A4. As a result, the displacement angle of the first oscillation unit 21 is maintained at a second angle D2 during the second period T1A-2. In the following description, maintaining the current value or displacement angle does not necessarily mean that the current value or displacement angle does not change strictly, but may also mean that the current value or displacement angle deviates within a predetermined range. The predetermined value here may be set arbitrarily, and may be, for example, 10% of the current value or displacement angle.

[0074] During the first period T1B-1, the current value of the drive signal switches from the fourth current value A4 to the third current value A3 and is maintained at the third current value A3 until the end of the first period T1B-1. As a result, the displacement angle of the first oscillation unit 21 changes from the second angle D2 to the reference angle D0 during the first period T1B-1. During the second period T1B-2, the drive signal switches to the current value A0 and is maintained at the current value A0 until the end of the second period T1B-2. As a result, the displacement angle of the first oscillation unit 21 is maintained at the reference angle D0 during the second period T1B-2.

[0075] During the first period T1C-1, the current value of the drive signal switches from current value A0 to second current value A2 and is maintained at the second current value A2 until the end of the first period T1C-1. As a result, the displacement angle of the first oscillation unit 21 changes from reference angle D0 to first angle D1 during the first period T1C-1. During the second period T1C-2, the current value of the drive signal is maintained at the first current value A1. As a result, the displacement angle of the first oscillation unit 21 is maintained at first angle D1 during the second period T1C-2.

[0076] During the first period T1D-1, the current value of the drive signal switches from the first current value A1 to the second current value A2 and is maintained at the second current value A2 until the end of the first period T1D-1. As a result, the displacement angle of the first oscillation unit 21 changes from the first angle D1 to the reference angle D0 during the first period T1D-1. During the second period T1D-2, the drive signal switches to the current value A0 and is maintained at the current value A0 until the end of the second period T1D-2. As a result, the displacement angle of the first oscillation unit 21 is maintained at the reference angle D0 during the second period T1D-2.

[0077] Note that light L is irradiated during periods T1A-2 and T1C-2. Therefore, during period T1A-2, light L is irradiated onto the first oscillation unit 21 held at the second angle D2, the optical path of light L shifts to the A operation position, and the image shifts by 1 / 4 pixel. Also, during period T1C-2, light L is irradiated onto the first oscillation unit 21 held at the first angle D1, the optical path of light L shifts to the D operation position, and the image shifts by 1 / 4 pixel. Therefore, there is a shift from the A operation position to the C operation position by half a pixel.

[0078] Meanwhile, in the second oscillation unit 22, during the first period T2A-1, the current value of the drive signal is switched from current value A0 to a third current value A3, and is maintained at the third current value A3 until the end of the first period T2A-1. Then, the current value changes to a fourth current value A4. As a result, the displacement angle of the second oscillation unit 22 changes from the reference angle D0 to the second angle D2 during the first period T2A-1.

[0079] During the second period T2A-2, the current value of the drive signal is maintained at the fourth current value A4, so that the displacement angle of the second oscillation part 22 is maintained at the second angle D2 during the second period T2A-2.

[0080] During the first period T2B-1, the current value of the drive signal switches from the fourth current value A4 to the third current value A3 and is maintained at the third current value A3 until the end of the first period T2B-1. As a result, the displacement angle of the second oscillation unit 22 changes from the second angle D2 to the reference angle D0 during the first period T2B-1. During the second period T2B-2, the current value of the drive signal is maintained at the current value A0. As a result, the displacement angle of the second oscillation unit 22 is maintained at the reference angle D0 during the second period T2B-2.

[0081] During the first period T2C-1, the current value of the drive signal switches from current value A0 to second current value A2 and is maintained at the second current value A2 until the end of the first period T2C-1. As a result, the displacement angle of the second oscillation unit 22 changes from reference angle D0 to first angle D1 during the first period T2C-1. During the second period T2C-2, the current value of the drive signal is maintained at the first current value A1. As a result, the displacement angle of the second oscillation unit 22 is maintained at first angle D1 during the second period T2C-2.

[0082] During the first period T2D-1, the current value of the drive signal switches from the first current value A1 to the second current value A2 and is maintained at the second current value A2 until the end of the first period T2D-1. As a result, the displacement angle of the second oscillation unit 22 changes from the first angle D1 to the reference angle D0 during the first period T2D-1. During the second period T2D-2, the drive signal switches to the current value A0 and is maintained at the current value A0 until the end of the second period T2D-2. As a result, the displacement angle of the second oscillation unit 22 is maintained at the reference angle D0 during the second period T2D-2.

[0083] Note that light L is irradiated during periods T2A-2 and T2C-2. Therefore, during period T2A-2, light L is irradiated onto the second oscillation unit 22 held at the second angle D2, the optical path of light L shifts to the A operation position, and the image shifts by 1 / 4 pixel. Also, during period T2C-2, light L is irradiated onto the first oscillation unit 21 held at the first angle D1, the optical path of light L shifts to the C operation position, and the image shifts by 1 / 4 pixel. Therefore, there is a shift of half a pixel from the A operation position to the C operation position.

[0084] 6, the waveform of the drive signal applied to the first actuator 25 (solid line in FIG. 6) and the waveform of the drive signal applied to the second actuator 26 (dotted line) are shifted by a predetermined period T12. Therefore, there is a shift by the predetermined period T12 between periods T1A-2 and T1C-2 during which the first oscillation unit 21 oscillates and irradiates light L and periods T2A-2 and T2C-2 during which the second oscillation unit 22 oscillates and irradiates light L. At this time, the second period T1A-2 during which the current value of the first actuator 25 is maintained at the fourth current value A4 overlaps with a neutral period T2D-2 during which the current value of the second actuator 26 is maintained at the current value A0, i.e., the current value is maintained at 0. Similarly, the second period T1C-2 during which the current value of the first actuator 25 is maintained at the first current value A1 overlaps with the neutral period T2B-2 during which the current value of the second actuator 26 is maintained at the current value A0, i.e., the current value is maintained at 0.

[0085] Furthermore, the second period TA-2 during which the current value of the second actuator 26 is maintained at the fourth current value A4 overlaps with a neutral period T1B-2 during which the current value of the first actuator 25 is maintained at the current value A0, i.e., the current value is 0. Similarly, the second period T2C-2 during which the current value of the second actuator 26 is maintained at the first current value A1 overlaps with a neutral period T1D-2 during which the current value of the first actuator 25 is maintained at the current value A0, i.e., the current value is 0.

[0086] 6, the natural frequency of first oscillating section 21 and the natural frequency of second oscillating section 22 are not necessarily the same, and the torsional rigidity of first oscillating section 21 and the torsional rigidity of second oscillating section 22 are not necessarily the same, so current values A1 to A4 of first oscillating section (solid line) 21 and current values A1 to A4 of second oscillating section (dotted line) 22 are not necessarily the same, and the lengths of periods T1A-1 and T2A-1, and periods T1B-1 and T2B-1 are not necessarily the same. The same applies to periods T1C and T2C, and periods T1D and T2D.

[0087] [Pixel operation by optical path control mechanism] The following describes the operation when swinging the first swinging part 21 and the second swinging part 22. Fig. 8 is an explanatory diagram for explaining the two-axis swing pattern of the optical part.

[0088] As shown in Figures 3 and 8, in the optical path control mechanism 12, when the horizontal arrangement direction of the pixels of the optical element 20 is the AY direction and the vertical arrangement direction of the pixels of the optical element 20 is the BY direction, the first oscillation axis AX direction and the second oscillation axis BX direction are arranged at an angle of 45 degrees with respect to the AY direction and the BY direction.

[0089] The first actuator 25 swings the first swinging unit 21 in response to the drive signal so as to repeatedly change its position around the first axis AX from the reference angle D0 to the second angle D2 and from the reference angle D0 to the first angle D1. As the first swinging unit 21 repeatedly swings between the first angle D1 and the second angle D2, the optical axis of the light L repeatedly shifts from the reference position to the A operating position and from the reference position to the C operating position.

[0090] That is, the image projected onto the screen by the light L when the optical axis is in the A operating position and the image projected onto the screen by the light L when the optical axis is in the C operating position are shifted by half a pixel. That is, the image projected onto the screen is shifted by 1 / 4 pixel from the reference position, but the shift is also shifted by half a pixel between the A operating position and the C operating position. In this way, the image is shifted by 1 / 4 pixel from the reference position and then moved back by 1 / 4 pixel, and then shifted by 1 / 4 pixel in the opposite direction and then moved back by 1 / 4 pixel, and this is repeated. This increases the apparent number of pixels, thereby increasing the resolution of the image projected onto the screen. Because the shift amount of the optical axis is half a pixel of the image, the first angle D1 and the second angle D2 are set to angles that can shift the image by 1 / 4 pixel. Note that the shift amount of the image is not limited to half a pixel and may be any amount, such as 1 / 2 or 1 / 8 of a pixel. The first angle D1 and the second angle D2 may also be set appropriately according to the shift amount of the image.

[0091] The second actuator 26 swings the second swinging unit 22 in response to the drive signals so as to repeatedly change its position around the first axis BX from the reference angle D0 to the second angle D2 and from the reference angle D0 to the first angle D1. As the second swinging unit 22 repeatedly swings between the first angle D1 and the second angle D2, the optical axis of the light L repeatedly shifts from the reference position to the B operating position and from the reference position to the D operating position.

[0092] That is, the image projected onto the screen by the light L when the optical axis is in the B operating position and the image projected onto the screen by the light L when the optical axis is in the D operating position are shifted by half a pixel. That is, the image projected onto the screen is shifted by 1 / 4 pixel from the reference position, but the shift is also half a pixel between the B operating position and the D operating position. In this way, the image is shifted by 1 / 4 pixel from the reference position and then moved back by 1 / 4 pixel, and then shifted by 1 / 4 pixel in the opposite direction and moved back by 1 / 4 pixel, and this is repeated. This increases the apparent number of pixels, thereby increasing the resolution of the image projected onto the screen. Because the shift amount of the optical axis is half a pixel of the image, the first angle D1 and the second angle D2 are set to angles that can shift the image by 1 / 4 pixel. Note that the shift amount of the image is not limited to half a pixel and may be any amount, such as 1 / 2 or 1 / 8 of a pixel. The first angle D1 and the second angle D2 may also be set appropriately according to the shift amount of the image.

[0093] A specific explanation will be given below. Image position P0 is the display position when the current value applied to the first actuator 25 and the second actuator 26 is 0, that is, when the displacement angle of the optical element 20 is 0. Operation state A is a state in which the first actuator 25 oscillates the optical element 20 by a predetermined angle around the first oscillation axis AX, and the image position P0 is shifted by 1 / 4 pixel in the direction of the second oscillation axis BX. In other words, operation state A is a state in which an image is displayed at image position P1.

[0094] In the B-operation state, the optical element 20 is swung by a predetermined angle around the second oscillation axis BX by the second actuator 26, and the image position P0 is shifted by 1 / 4 pixel in the direction of the first oscillation axis AX. That is, the B-operation state is a state in which an image is displayed at the image position P2. Similarly, the C-operation state is a state in which an image is displayed at the image position P3. Similarly, the D-operation state is a state in which an image is displayed at the image position P4.

[0095] [Drive waveform] 9 is a graph illustrating the relationship between the waveform of the drive signal of the drive unit and the oscillation pattern of the optical unit. Note that, in the following explanation, the waveform of the drive signal applied to the first actuator 25 and the oscillation pattern of the first oscillation unit 21 will be explained, but the same applies to the second actuator 26 and the second oscillation unit 22.

[0096] 9, when the first actuator 25 is applied with a current value A0, the first oscillating unit 21 is in a reference position (displacement angle 0). At the start of a first period T1A-1, the current value is switched to a third current value A3, which is maintained until the end of the first period T1A-1. The length of the first period T1A-1 corresponds to half the period of the natural frequency of the first oscillating unit 21, and the third current value A3 is half the fourth current value A4, which is the peak current value. During the first period T1A-1, the displacement angle of the first oscillating unit 21 changes from the reference angle D0 to the second angle D2. At the start of a second period T1A-2, the current value is switched to a fourth current value A4, which is maintained until the end of the second period T1A-2. Then, the first oscillation part 21 is maintained at the second angle D2 in the second period T1A-2.

[0097] Next, at the start of the first period T1B-1, the current value is switched to the third current value A3, which is maintained until the end of the first period T1B-1. Here, the length of the first period T1B-1 corresponds to 1 / 2 of the natural vibration period of the first oscillation part 21. Then, during the first period T1B-1, the displacement angle of the first oscillation part 21 changes from the second angle D2 to the reference angle D0. Then, at the start of the second period T1B-2, the current value is switched to the current value A0, which is maintained until the end of the second period T1B-2. Then, during the second period T1B-2, the first oscillation part 21 is maintained at the reference angle D0.

[0098] By applying a step-shaped waveform to the drive signal applied to the first actuator 25, the displacement angle of the first oscillator 21 can be maintained at the second angle D2 and the reference angle D0. The same applies to periods T1C and T1D.

[0099] [Actuator power consumption] FIG. 10 is a schematic diagram illustrating the power consumption when the drive signal is a trapezoidal wave, and FIG. 11 is a schematic diagram illustrating the power consumption when the drive signal is a step wave.

[0100] 10, when the waveform of the drive signal applied to the first actuator 25 and the second actuator 26 is trapezoidal, the power consumption, which is the area between the current value A0 and the trapezoidal wave (shaded area), increases. On the other hand, as shown in Fig. 11, when the waveform of the drive signal applied to the first actuator 25 and the second actuator 26 is stepwise, the power consumption, which is the area between the current value A0 and the stepwise wave (shaded area), decreases compared to the trapezoidal wave.

[0101] (effect) As described above, the light path control device of this embodiment comprises an oscillating unit 12A having an optical element (optical unit) 20 onto which light is incident, an actuator 12B that oscillates the oscillating unit 12A, and a drive circuit (drive unit) 16 that applies a drive signal of a current value to the actuator 12B, and the drive circuit 16 applies a current value that is half the peak current value for a period that is half the period of the natural vibration of the oscillating unit 12A, and then maintains the current value at the peak current value or at zero.

[0102] According to the light path control device of this embodiment, by applying a current value that is half the peak current value for a period that is half the natural vibration period of oscillating unit 12A, and then maintaining the current value at the peak current value or 0, oscillating unit 12A can be easily stopped at a predetermined position, reducing the power consumption of actuators 25, 26. In addition, because the displacements of each axis for tilting the optical member are independent, there is no need to adjust the balance of the displacement amounts of each of the two axes, simplifying the control of actuators 25, 26. Because the A operating position and the C operating position are determined by the displacement of the first oscillating unit, and the B operating position and the D operating position are determined by the displacement of the second oscillating unit, adjustments can be made more easily than a method in which each operating position (A operating position to D operating position) is determined by simultaneously moving two axes.

[0103] Furthermore, in the light path control device according to this embodiment, the drive circuit 16 can stop the oscillation unit 12A at the first angle (first tilt angle) D1 or the second angle (second tilt angle) D2 by maintaining a positive or negative peak current value, and can stop the oscillation unit 12A at a reference angle D0 that is intermediate between the first angle D1 and the second angle D2 by maintaining the current value at 0. This allows for simplified control of the actuators 25 and 26.

[0104] Furthermore, in the light path control device according to this embodiment, the drive signal of the current value applied by the drive circuit 16 to the first actuator 25 and the second actuator 26 has a staircase-shaped waveform. Therefore, since the first actuator 25 and the second actuator 26 are driven by the drive signal having a staircase-shaped waveform, the first oscillating unit 21 and the second oscillating unit 22 can be stopped at a predetermined position with high precision.

[0105] Moreover, the display device according to this embodiment includes the light path control device 10 and an irradiation device 100 that irradiates the swinging portion 12A with light L. Therefore, by including the light path control device 10, the display device 1 can reduce the power consumption of the actuators 25, 26 and simplify the control of the actuators 25, 26.

[0106] Furthermore, the optical path control method according to this embodiment is an optical path control method that controls the optical path by applying a drive signal to actuator 12B that oscillates oscillating unit 12A having optical member 20 onto which light is incident, and after applying a current value that is half the peak current value to actuator 12B for a period that is half the natural vibration period of oscillating unit 12A, the current value is maintained at the peak current value or a current value of 0. This makes it possible to reduce the power consumption of actuators 25, 26 and simplify the control of actuators 25, 26.

[0107] In the above-described embodiment, the optical element 20 is supported by the first oscillating unit 21, the first oscillating unit 21 is oscillably supported by the second oscillating unit 22, and the second oscillating unit 22 is oscillably supported by the support unit 27. However, the present invention is not limited to this configuration. For example, a first optical path control device configured by supporting the first optical element on the first oscillating unit and oscillably supporting the first oscillating unit on the first support unit, and a second optical path control device configured by supporting the second optical element on the second oscillating unit and oscillably supporting the second oscillating unit on the second support unit may be configured by overlapping them in the light irradiation direction. Furthermore, the optical element 20 is not limited to a two-axis oscillating configuration, and may be a one-axis oscillating configuration.

[0108] The optical path control device 10 according to the present invention has been described above, but it may be embodied in various different forms other than the above-described embodiment.

[0109] Each component of the illustrated optical path control device 10 is a functional concept, and does not necessarily have to be physically configured as shown in the drawing. In other words, the specific form of each device is not limited to that shown in the drawing, and all or part of it may be functionally or physically distributed or integrated in any unit depending on the processing load and usage status of each device.

[0110] The configuration of the light path control device 10 is realized, for example, as software by a program loaded into memory. In the above embodiment, the functional blocks are described as being realized by the cooperation of these hardware and software. In other words, these functional blocks can be realized in various forms by hardware alone, software alone, or a combination of both.

[0111] The above-described components include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the above-described configurations can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the configurations are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0112] 1 Display device 10 Optical path control device 12 Optical path control mechanism 12A Swinging part 12B Actuator 14 Control circuit 16 Drive circuit (drive unit) 20 Optical components (optical part) 21 First swinging part 22 Second swinging part 23 First shaft 24 Second shaft 25 First Actuator 26 Second Actuator 27 Support part 31 1st moving part 32 Second moving part 41,44 Coil 42,45 yoke 43,46 Magnets 100 Irradiation device AX 1st swing axis BX Second swing axis

Claims

1. a swinging unit having an optical unit into which light is incident; an actuator that swings the swinging portion; a drive unit that applies a drive signal of a current value to the actuator; Equipped with the drive unit applies a current value that is half the peak current value for a period that is half the natural vibration period of the oscillation unit, and then maintains the current value at the peak current value or at 0; the optical unit transmits light incident on one surface and emits it from the other surface, The actuator includes a coil, a yoke, and a magnet. Optical path control device.

2. the drive unit can stop the oscillating unit at a first tilt angle or a second tilt angle by maintaining the peak current value at a positive or negative value, and can stop the oscillating unit at a reference position intermediate between the first tilt angle and the second tilt angle by maintaining the current value at 0. The optical path control device according to claim 1 .

3. the drive signal of the current value applied by the drive unit to the actuator has a waveform in the form of a staircase.

3. The optical path control device according to claim 1 or 2.

4. The optical path control device according to any one of claims 1 to 3, an irradiation device that irradiates the optical unit with light; A display device comprising:

5. An optical path control method for controlling an optical path by applying a drive signal to an actuator that oscillates an oscillating unit having an optical unit into which light is incident, comprising: applying a current value that is half the peak current value to the actuator for a period that is half the natural vibration period of the oscillating portion, and then maintaining the current value at the peak current value or at 0; the optical unit transmits light incident on one surface and emits it from the other surface, The actuator includes a coil, a yoke, and a magnet. Optical path control method.

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