Optical path control device and display device

Abstract

To provide an optical path controller and a display device in which the waveform of a drive signal for driving an actuator is automatically adjusted in order to reduce work man-hours.SOLUTION: The present invention comprises: a swing part having an optical part which light enters; an actuator for causing the swing part to swing; a drive part for applying, to the actuator, a drive signal of a waveform that includes a first period in which a current value is changed and a second period in which the current value is retained, so as to cause the swing part to swing and control an optical path; a vibration sensor for detecting the number of vibrations of the swing part; and a parameter setting part for setting a drive signal of the waveform, on the basis of the number of vibrations of the swing part detected by the vibration sensor.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] An optical device that shifts the optical axis by swinging an optical unit through which light is incident is known. For example, Patent Documents 1 and 2 below describe a technique that can increase the resolution of an image projected compared to the resolution of an optical modulation device by swinging an optical unit to shift the optical path of light transmitted through the optical unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an optical device, a driving unit drives an actuator by applying a driving signal to the actuator, causing the optical unit to swing. The waveform of the driving signal output by the driving unit is adjusted to a predetermined waveform in advance. However, for example, during the assembly of the optical device, due to variations in the mounting of components, changes over time, environmental temperature, etc., the natural frequency of the swinging unit may change. In this case, there is a problem that readjustment of the waveform of the driving signal becomes difficult.

[0005] In view of the above problems, an object of the present invention is to provide an optical path control device and a display device that automatically adjust the waveform of a driving signal for driving an actuator to reduce the man-hour.

Means for Solving the Problems

[0006] An optical path control device according to an aspect of the present invention includes a swinging part having an optical part through which light is incident, an actuator that swings the swinging part, and a driving part that controls an optical path of light transmitted through the optical part by swinging the swinging part by applying a driving signal having a waveform including a first period in which a current value changes and a second period in which the current value is held to the actuator, a vibration sensor that detects a vibration frequency of the swinging part, and a parameter setting part that sets the driving signal having the waveform based on the vibration frequency of the swinging part detected by the vibration sensor.

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

Advantages of the Invention

[0008] According to the present invention, it is possible to reduce the man-hours by automatically adjusting the waveform of the driving signal for driving the actuator.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below.

[0011] <First Embodiment> [Schematic Configuration of Display Device] FIG. 1 is a schematic diagram of a display device according to the first embodiment.

[0012] In the first embodiment, as shown in FIG. 1, the display device 1 includes an optical path control device 10 and an irradiation device 100. The irradiation device 100 is a device that irradiates light L for an image. The optical path control device 10 is a device that controls the optical path of the light L. The optical path control device 10 shifts the optical axis of the light L to shift the position of the image displayed by the light L, and makes the resolution of the projected image higher than the resolution of the image (that is, the number of pixels of the display element 106 described later) by the irradiation device 100.

[0013] The irradiation device 100 includes a light source 101, polarizing plates 105R, 105G, 105B, display elements 106R, 106G, 106B, polarizing plates 107R, 107G, 107B, a color synthesis prism 108, a projection lens 109, dichroic mirrors 120, 121, reflection mirrors 130, 131, lenses 140, 141, 142, 143, 144, 145, a polarization conversion element 150, and a video signal processing circuit 160. When not distinguishing between the display element 106R, the display element 106G, and the display element 106B, they are described as the display element 106.

[0014] 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, as an example, one light source 101 is used as the light source that irradiates the incident light L0, but it may have other optical devices for generating the incident light L0.

[0015] The incident light L0 from the light source 101 is incident on the lens 140. The lens 140 and the lens 141 are, for example, fly-eye lenses. The incident light L0 is made to have a uniform illumination distribution by the lenses 140 and 141 and is incident on the polarization conversion element 150. The polarization conversion element 150 is an element that aligns the polarization of the incident light L0 and has, for example, a polarization beam splitter and a retardation plate. The polarization conversion element 150 aligns the incident light L0 to p-polarized light, for example.

[0016] The incident light L0 whose polarization has been aligned by the polarization conversion element 150 is irradiated onto the dichroic mirror 120 through the lens 142. The lens 142 is a condenser lens, for example.

[0017] The dichroic mirror 120 separates the incident light L0 into yellow light LRG and blue light LB containing components in the blue band. The yellow illumination light LRG separated by the dichroic mirror 120 is reflected by the reflection mirror 130 and is incident on the dichroic mirror 121.

[0018] The dichroic mirror 121 separates the incident yellow light LRG into red light LR containing components in the red band and green light LG containing components in the green band.

[0019] The red light LR separated by the dichroic mirror 121 is irradiated onto the polarizing plate 105R through the lens 143. The green light LG separated by the dichroic mirror 121 is irradiated onto the polarizing plate 105G through 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 through the lens 145.

[0020] The polarizing plates 105R, 105G, 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, 105B reflect s-polarized light and transmit p-polarized light. The polarizing plates 105R, 105G, 105B are also referred to as reflective polarizing plates.

[0021] The red light LR, which is p-polarized, passes through the polarizing plate 105R and is irradiated onto the display element 106R. The green light LG, which is p-polarized, passes through the polarizing plate 105G and is irradiated onto the display element 106G. The blue light LB, which is p-polarized, passes through the polarizing plate 105B and is irradiated onto the display element 106B.

[0022] The display element 106R, the display element 106G, and the display element 106B are, for example, reflective liquid crystal display elements. In the following description, the case where the display element 106R, the display element 106G, and the display element 106B are reflective liquid crystal display elements will be taken as an example for explanation, but it is not limited to the reflective type, and a configuration using a transmissive liquid crystal display element may also be used. Further, the present invention can be variously applied to configurations using other display elements instead of the liquid crystal display element.

[0023] It is indicated that 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 the image data of the red component. The display element 106R optically modulates the red light LR of p-polarization and generates the red light LR of s-polarization in response to the control of the video signal processing circuit 160. 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 based on the image data of the green component. The display element 106G optically modulates the green light LG of p-polarization and generates the green light LG of s-polarization in response to the control of the video signal processing circuit 160. 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 based on the image data of the blue component. The display element 106B optically modulates the blue light LB of p-polarization based on the image data of the blue component and generates the blue light LB of s-polarization.

[0024] The polarizing plates 107R, 107G, and 107B have the characteristic of transmitting either s-polarization or p-polarization and reflecting or absorbing the other. For example, the polarizing plates 107R, 107G, and 107B transmit s-polarization and absorb unnecessary p-polarization.

[0025] The s-polarized red light LR generated by the display element 106R is reflected by the polarizing plate 105R, transmitted through the polarizing plate 107R, and irradiated onto the color synthesis prism 108. The s-polarized green light LG generated by the display element 106G is reflected by the polarizing plate 105G, transmitted through the polarizing plate 107G, and irradiated onto the color synthesis prism 108. The s-polarized blue light LB generated by the display element 106B is reflected by the polarizing plate 105B, transmitted through the polarizing plate 107B, and irradiated onto the color synthesis prism 108.

[0026] The color synthesis prism 108 synthesizes the incident red light LR, green light LG, and blue light LB, and irradiates the projection lens 109 with the light L for image display. The light L is projected onto a screen (not shown) or the like via the projection lens 109.

[0027] Note that although the irradiation device 100 has the above-described configuration, its configuration is not limited to the above description and may be any configuration.

[0028] The optical path control device 10 includes an optical path control mechanism 12, a control circuit (control unit) 14, and a drive circuit (drive unit) 16. The optical path control mechanism 12 is a mechanism that swings by being driven by the drive circuit 16. The optical path control mechanism 12 is provided between the color synthesis prism 108 and the projection lens 109 in the direction along the optical path of the light L. The optical path control mechanism 12 swings while the light L from the color synthesis prism 108 is incident, thereby shifting the traveling direction (optical path) of the light L and emitting it toward the projection lens 109. In this way, the optical path control device 10 controls the optical path of the light L so that the optical path of the light L shifts. Note that the position where the optical path control mechanism 12 is provided is not limited to between the color synthesis prism 108 and the projection lens 109 and may be arbitrary.

[0029] [Functional Configuration of Display Device] FIG. 2 is a block diagram schematically showing the circuit configuration of the display device.

[0030] As shown in FIG. 2, the video signal processing circuit 160 controls the display elements 106R, 106B, and 106G. A video signal including image data for controlling the display elements 106R, 106B, and 106G and a synchronization signal is input to the video signal processing circuit 160. 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 and a converter 14B. 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 converter 14B is a DA converter that converts a digital signal into an analog signal. The converter 14B converts the digital drive signal generated by the digital circuit 14A into an analog drive signal. The drive circuit 16 receives the analog drive signal from the converter 14B, amplifies the analog drive signal, and outputs it to the actuator 12B of the optical path control mechanism 12 described later. The actuator 12B is driven in response to the drive signal and swings the swing part 12A (see FIG. 3) described later.

[0031] [Optical Path Control Mechanism] FIG. 3 is a plan view showing the optical path control mechanism, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a sectional view taken along line V-V of FIG. 3.

[0032] As shown in FIGS. 3 to 5, the optical path control mechanism 12 includes a swing part 12A including an optical member (optical part) 20 on which light L is incident, and an actuator 12B that swings the swing part 12A.

[0033] Actuator 12B swings the swing part 12A about a first swing axis AX and a second swing axis BX along two directions that intersect (preferably, are orthogonal to) the direction in which the light L enters the optical member 20. The first swing axis AX and the second swing axis BX are preferably orthogonal to each other. Therefore, the optical path control mechanism 12 includes a first swing part 21 and a second swing part 22 as the swing part 12A, a first shaft part 23 and a second shaft part 24 along the first swing axis AX and the second swing axis BX, a first actuator 25 and a second actuator 26 as the actuator 12B, and a support part 27.

[0034] The optical member 20 is a member that transmits the incident light L. The light L enters the optical member 20 from one surface, passes through the incident light L, and exits the light L from the other surface. The optical member 20 is a glass plate, but the material and shape may be arbitrary.

[0035] The first swing part 21 includes the 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 member having a frame shape of a plate material in which a through hole 31a is formed at the center. The optical member 20 is fixed to the first movable part 31 in a state of being 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 an adhesive for fixing to the first movable part 31, but the method of fixing the optical member 20 to the first movable part 31 may be arbitrary.

[0036] The second swing part 22 is arranged outside the first swing part 21. The second swing 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 swingably supported with respect to the second movable part 32 about a first swing axis AX. Specifically, the second movable part 32 is a member having a frame shape of a plate material with a through hole 32a formed in the center. The first movable part 31 is swingably supported by the second movable part 32 in a state where a predetermined gap is provided in the through hole 32a of the second movable part 32. The first movable part 31 and the second movable part 32 are connected by a pair of first shaft parts 23 along the first swing axis AX. The first movable part 31 swings about the first swing axis AX by elastically deforming so that the pair of first shaft parts 23 are twisted with respect to the second movable part 32.

[0037] The support part 27 is arranged outside the second swing part 22. The support part 27 is a member that supports the second movable part 32. The second movable part 32 is swingably supported with respect to the support part 27 about a second swing axis BX. Specifically, the support part 27 is a member having a frame shape of a plate material with a through hole 27a formed in the center. The second movable part 32 is swingably supported by the support part 27 in a state where a predetermined gap is provided in the through hole 27a of the support part 27. The second movable part 32 and the support part 27 are connected by a pair of second shaft parts 24 along the second swing axis BX. The second movable part 32 swings about the second swing axis BX by elastically deforming so that the pair of second shaft parts 24 are twisted with respect to the support part 27.

[0038] The second movable part 32 (second swing part 22) swings about the second swing axis BX with a pair of second shaft parts 24 as fulcrums with respect to the support part 27. The first movable part 31 (first swing part 21) swings about the first swing axis AX with a pair of first shaft parts 23 as fulcrums with respect to the second movable part 32. Therefore, the optical member 20 fixed to the second movable part 32 can swing about the first swing axis AX and the second swing axis BX. By swinging the optical member 20 about the first swing axis AX and the second swing axis BX, the optical path of the light L transmitted through the optical member 20 can be shifted due to the change in the posture of the optical member 20.

[0039] In the first 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 swings with respect to the second movable part 32 by elastically deforming so that the first shaft part 23 is twisted in the circumferential direction. However, the first movable part 31, the second movable part 32, and the first shaft part 23 may be separately formed and connected. Further, one end portion and the other end portion in the axial direction of the second swing shaft BX in the second movable part 32 are fixed to be connected to the support part 27, and the second shaft parts 24 are respectively formed at the respective end portions of the second movable part 32. However, the second shaft parts 24 may be respectively provided at the respective end portions of the second movable part 32, and each second shaft part 24 may be directly fixed to be connected to the support part 27. Furthermore, the second movable part 32, the second shaft part 24, and the support part 27 may be integrally formed.

[0040] The first actuator 25 swings the first movable part 31 (the first swing part 21) about the first swing axis AX with a pair of the first shaft parts 23 as fulcrums with respect to the support part 27. The first actuator 25 is arranged on both one side and the other side in the radial direction (the axial direction in the second swing axis BX) from the first swing axis AX. The first actuator 25 includes a coil 41, a yoke 42, and a magnet 43.

[0041] 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 coil 41 is respectively provided at both end portions in the radial direction of the first swing axis AX of the first movable part 31 (one side and the other side in the axial direction in the second swing 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 to the support part 27. The yoke 42 is respectively arranged at both end portions of the first movable part 31 corresponding to the coil 41. The magnet 43 is a permanent magnet. The magnet 43 is attached to the yoke 42 and fixed to the yoke 42. The magnet 43 is arranged at a position adjacent to each coil 41.

[0042] A drive signal from the drive circuit 16 (see FIG. 2) is input to the coil 41. In the example shown in FIG. 5, a magnet 43 is adhered to one side of a yoke 42 having a U shape, and an air gap is formed between the surface of the magnet 43 that is not adhered and the opposing surface of the yoke 42 having a U shape. 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 within the air gap (magnetic field) formed by the magnet 43 and the yoke 42, and a force is generated in the coil 41. Due to this force, the first movable part 31 (first swing part 21) fixed to the coil 41 is swung. That is, it can be said that the first actuator 25 is an electromagnetic actuator constituted by the coil 41, the yoke 42, and the magnet 43.

[0043] The second actuator 26 swings the second movable part 32 (second swing part 22) about the second swing axis BX with a pair of second shaft parts 24 as fulcrums with respect to the support part 27. The second actuator 26 is disposed on both one side and the other side in the radial direction (axial direction at the first swing axis AX) from the second swing axis BX. The second actuator 26 includes a coil 44, a yoke 45, and a magnet 46.

[0044] 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 coil 44 is provided at both end parts in the radial direction of the second swing axis BX of the second movable part 32 (one side and the other side in the axial direction at the first swing axis AX), respectively. The yoke 45 is a member that forms a magnetic path. The yoke 45 is attached to the support part 27 and fixed to the support part 27. The yoke 45 is disposed at both end parts of the second movable part 32 corresponding to the coil 44, respectively. The magnet 46 is a permanent magnet. The magnet 46 is attached to the yoke 45 and fixed to the yoke 45. The magnet 46 is disposed at a position adjacent to each coil 44.

[0045] A drive signal from the drive circuit 16 (see FIG. 2) is input to the coil 44. In the example shown in FIG. 4, a magnet 46 is adhered to one side of a yoke 45 having a U shape, and an air gap is formed between the surface of the magnet 46 that is not adhered and the opposing surface of the yoke 45 having the U shape. 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 within the air gap (magnetic field) formed by the magnet 46 and the yoke 45, generating a force on the coil 44. This force causes the second movable part 32 (second swing part 22) fixed to the coil 44 to swing. That is, it can be said that the second actuator 26 is an electromagnetic actuator constituted by the coil 44, the yoke 45, and the magnet 46.

[0046] When the first movable part 31 provided with the optical member 20 swings and the second movable part 32 supporting the first movable part 31 swings, the optical path control mechanism 12 can be said to be constituted by the optical member 20, the first movable part 31, the second movable part 32, and the coils 41 and 44. That is, it can be said that the portion of the optical path control mechanism 12 that swings with respect to the support part 27 indicates the swing part 12A. Since the first shaft part 23 also swings together with the second movable part 32, it is included in the swing part 12A. Further, when fixing members, adhesives for fixing the optical member 20 to the first movable part 31, substrates, lead wires, etc. for passing current through the coils 41 and 44 are provided, these also swing with respect to the support part 27 and are thus included in the swing part 12A.

[0047] In the first embodiment, the first movable part 31 is swung by the first actuator 25, and the second movable part 32 is swung by the second actuator 26. In this case, the yokes 42 and 45 constituting the respective actuators 25 and 26 are fixed to the support part 27. Therefore, when the second movable part 32 is swung by the second actuator 26, a gap is ensured between the two so that the first actuator 25 and the second movable part 32 do not interfere with each other. Note that the first actuator 25 may be provided on the second movable part 32.

[0048] Note that the actuators 25 and 26 were of the so-called moving coil type in which coils 41 and 44 were arranged in the movable parts 31 and 32, but the present invention is not limited thereto. For example, it may be of the so-called moving magnet type in which magnets 43 and 46 are arranged in the movable parts 31 and 32 and coils 41 and 44 are arranged in the support part 27. In this case, since the magnets 43 and 46 are swung together with the optical member 20, the magnets 43 and 46 are included in the swing part 12A instead of the coils 41 and 44.

[0049] The optical path control mechanism 12 has the above-described configuration, but is not limited thereto, and may have any configuration in which the optical path of the light L can be shifted by the optical part swinging by an actuator to which a drive signal is applied.

[0050] [First shaft portion and second shaft portion] FIG. 6 is a perspective view showing a swing part in the optical path control mechanism.

[0051] As shown in FIG. 6, the first movable part 31 constituting the first swing part 21 and the second movable part 32 constituting the second swing part 22 are connected by a first shaft part 23 along the first swing axis AX, and the second movable part 32 and the support part 27 are connected by a second shaft part 24 along the second swing axis BX. Here, the mass of the first swing part 21 and the distance from the first swing axis AX to the outer peripheral part of the first movable part 31 are different from the mass of the second swing part 22 and the distance from the second swing axis BX to the outer peripheral part of the second swing part 32. Therefore, the moment of inertia when the first movable part 31 is swung about the first swing axis AX with the first shaft part 23 as a fulcrum by the first actuator 25 is different from the moment of inertia when the second movable part 32 is swung about the second shaft part 24 as a fulcrum by the second actuator 26.

[0052] That is, the moment of inertia I1 of the first movable part 31 when the first movable part 31 is swung about the first swing axis AX with the first shaft part 23 as a fulcrum by the first actuator 25 can be considered as follows. Considering the first movable part 31 as an aggregate of mass points with a mass of m1 and the distance from the first swing axis AX of the mass point (the radius of rotation of the mass point) as r1, the moment of inertia of the rotating mass point is expressed by the following formula. I1 = m1·r1 2 Since the first movable part 31 can be considered as an aggregate of mass points, the moment of inertia I of the first movable part 31 about the first swing axis AX is represented by the sum of the products of the mass m1 of the minute part which is a mass point of the first movable part 31 and the square of the distance (radius of rotation r1) from the first swing axis AX.

[0053] Similarly, the moment of inertia I2 of the second movable part 32 when the second movable part 32 is swung around the second swing axis BX with the second shaft portion 24 as a fulcrum by the second actuator 26 is represented by the sum of the products of the mass m2 of the minute part which is a mass point of the second movable part 32 and the square of the distance (radius of rotation r2) from the second swing axis BX. Therefore, the moment of inertia when the first movable part 31 is swung about the first swing axis AX is different from the moment of inertia when the second movable part 32 is swung about the second swing axis BX.

[0054] Then, the natural frequency when the first movable part 31 swings is different from the natural frequency when the second movable part 32 swings, and the displacement times of both are different. In the display device 1, an image may be displayed during the swing of the optical member 20. If the displacement time of the first movable part 31 is different from the displacement time of the second movable part 32, the appearance of the image drawn during each swing is different, and the image quality deteriorates.

[0055] In the first embodiment, the torsional rigidity of the second shaft portion 24 is set to be higher than the torsional rigidity of the first shaft portion 23. By making at least one of the cross-sectional area, length, and material different between the first shaft portion 23 and the second shaft portion 24, the torsional rigidity of the second shaft portion 24 is made higher than the torsional rigidity of the first shaft portion 23.

[0056] The natural frequencies of the first movable part 31 and the second movable part 32 are determined by the moment of inertia about the axis and the torsional rigidity of the axis. The moment of inertia about the axis is determined by the masses of the first swinging part 21 and the second swinging part 22, the distance from the first swing axis AX to the first movable part 31, and the distance from the second swing axis BX to the second movable part 32. On the other hand, the torsional rigidity of the axis is determined by the cross-sectional areas, lengths, and materials of the first shaft part 23 and the second shaft part 24. Since the distance from the second swing axis BX to the second movable part 32 is longer than the distance from the first swing axis AX to the first movable part 31, the second movable part 32 has a larger moment of inertia and a lower natural frequency than the first movable part 31. Therefore, by making the torsional rigidity of the second shaft part 24 higher than that of the first shaft part 23, the moment of inertia of the second movable part 32 is reduced and the natural frequency is increased. Then, the natural frequencies of the first movable part 31 and the second movable part 32 are approximated, and preferably, they become equal.

[0057] When the natural frequencies of the first movable part 31 and the second movable part 32 become the same, the displacement times of the first movable part 31 and the second movable part 32 are the same, so the appearance of the images captured during their respective swings is the same, and a decrease in image quality is suppressed.

[0058] In the first embodiment, the first shaft portion 23 and the second shaft portion 24 are made of the same material. The first shaft portion 23 and the second shaft portion 24 have the same radial lengths L1 and L2. The first shaft portion 23 and the second shaft portion 24 have different cross-sectional areas. The cross-sectional area of the first shaft portion 23 is width W1 × thickness T1, and the cross-sectional area of the second shaft portion 24 is width W2 × thickness T2. And since the torsional rigidity height is proportional to the cross-sectional area, the cross-sectional area of the first shaft portion 23 (width W1 × thickness T1) < the cross-sectional area of the second shaft portion 24 (width W2 × thickness T2) is set. Note that since the torsional rigidity height is inversely proportional to the axial length, the length L1 of the first shaft portion 23 > the length L2 of the second shaft portion 24 may be used. By making at least one of the cross-sectional area, length, and material different between the first shaft portion 23 and the second shaft portion 24, the torsional rigidity of the second shaft portion 24 is made higher than the torsional rigidity of the first shaft portion 23. For example, when the thicknesses T1 and T2 of the first shaft portion 23 and the second shaft portion 24 are the same, and the axial lengths L1 and L2 of the first shaft portion 23 and the second shaft portion 24 are the same, by making the width W2 of the second shaft portion 24 larger than the width W1 of the first shaft portion 23, the torsional rigidity of the second shaft portion > the torsional rigidity of the first shaft portion can be made different.

[0059] [Drive signal] Here, the drive signal applied from the drive circuit 16 to the actuator 12B will be described. FIG. 7 is a graph for explaining the waveform of the drive signal of the drive unit.

[0060] As shown in FIG. 7, the drive signal applied from the drive circuit 16 to the first actuator 25 is an electrical signal, and the current value changes over time. Hereinafter, the waveform representing the change in the current value of the drive signal for each time will be referred to as the waveform of the drive signal. The waveform of the drive signal is shown by a solid line in FIG. 7. The drive signal is a signal in which the same waveform is repeated every period T. The period T includes a period T1 and a period T2 that is after the period T1 and continuous with the period T1. The period T1 corresponds to the period in which the image (image not shifted by half a pixel) when the optical axis of the light L is in the first position is displayed, and the period T2 corresponds to the period in which the image (image shifted by half a pixel) when the optical axis of the light L is in the second position is displayed.

[0061] The drive signal changes in current value from a first current value A1 to a second current value A2 during a first period TA1 within a period T1. Here, the intermediate position 0 between the first current value A1 and the second current value A2 is the position where the current value becomes 0. The drive signal linearly changes in current value from the first current value A1 to the second current value A2 over time during the first period TA1. That is, at the start timing of the first period TA1, the current value of the drive signal is the first current value A1, and then the current value linearly changes from the first current value A1 and becomes the second current value A2 at the end timing of the first period TA1. The first current value A1 is a current value capable of holding the first oscillating part 21 at a first angle D1, and is set according to the numerical value of the first angle D1. The second current value A2 is a current value capable of holding the first oscillating part 21 at a second angle D2, and is set according to the numerical value of the second angle D2. The first current value A1 and the second current value A2 are current values with opposite polarities, and their absolute values may be equal. In FIG. 7, it is illustrated that the first current value A1 is negative and the second current value A2 is positive.

[0062] The length of the first period TA1 corresponds to the natural frequency of the first oscillating part 21. The first oscillating part 21 refers to the part (in the first embodiment, the optical member 20, the first movable part 31, the coil 41) that oscillates with respect to the support part 27 in the optical path control mechanism 12. That is, it can be said that the length of the first period TA1 corresponds to the natural frequency of the part that oscillates with respect to the support part 27. More specifically, the length of the first period TA1 is preferably substantially the same value as the natural period of the first oscillating part 21, and more preferably the same value as the natural period. Here, the natural period is the reciprocal of the natural frequency. Also, the "substantially the same value" means that a value deviated by the degree of the error range with respect to the natural period is also allowed. For example, even when the deviation with respect to the natural period is within 5% of the value of the natural period, it may be regarded as the "substantially the same value". Hereinafter, the description of the "substantially the same value" refers to the same meaning. Note that the value of the natural vibration (the reciprocal of the natural frequency) is expressed as "1 / f" [s] when the natural frequency is f [Hz].

[0063] The drive signal has a current value held at a second current value A2 during a second period TB1 within a period T1. The second period TB1 is a period that comes after and is continuous with the first period TA1. Note that by increasing the natural frequency of the first oscillating part 21, the first period TA1 can be shortened and the second period TB1 can be lengthened (for example, it can be made longer than the first period TA1), which is preferable. Note that the statement that the current value is held at the second current value A2 is not limited to the case where the current value does not strictly change from the second current value A2, and may also include the case where the current value deviates within a predetermined value range from the second current value A2. The predetermined value here may be arbitrarily set, and for example, it may be a value of 10% of the second current value A2.

[0064] In this way, during the period T1, the current value of the drive signal gradually changes from the first current value A1 to the second current value A2, and once the current value reaches the second current value A2, the current value is held at the second current value A2.

[0065] During a third period TA2 within a period T2, the current value of the drive signal changes from the second current value A2 to the first current value A1. The third period TA2 can be said to be a period that comes after and is continuous with the second period TB1. More specifically, during the third period TA2, the current value of the drive signal changes linearly over time from the second current value A2 to the first current value A1. That is, at the start timing of the third period TA2, the current value of the drive signal is the second current value A2, and then the current value changes linearly from the second current value A2, and at the end timing of the third period TA2, the current value becomes the first current value A1.

[0066] The length of the third period TA2 is a value corresponding to the natural frequency of the first oscillating part 21. More specifically, it is preferably a value substantially the same as the natural period (the reciprocal of the natural frequency) of the first oscillating part 21, and more preferably the same value as the natural period. In the third period TA2, the length of the third period TA2 is equal to the length of the first period TA1.

[0067] During the fourth period TB2 within the period T2, the current value is held at the first current value A1. The fourth period TB2 is a period that comes after the third period TA2 and is continuous with the third period TA2. Also, the fourth period TB2 is a period that comes before the first period TA1 and is continuous with the first period TA1. The fourth period TB2 is equal to the second period TB1. By increasing the natural frequency of the first oscillating part 21, the third period TA2 can be shortened and the fourth period TB2 can be lengthened (for example, it can be made longer than the third period TA2), which is preferable. Note that being held at the first current value A1 is not limited to the current value not strictly changing from the first current value A1, and may also include the current value deviating within a predetermined value range from the first current value A1. The predetermined value here may be arbitrarily set, for example, it may be a value of 10% of the first current value A1.

[0068] In this way, in the period T2, the drive signal gradually changes from the second current value A2 to the first current value A1, and once the current value reaches the first current value A1, the current value is held at the first current value A1.

[0069] As described above, in the first embodiment, the waveform of the drive signal is trapezoidal, and the first period TA1 and the third period TA2 during which the current value changes are values corresponding to the natural frequency of the oscillating part 12A.

[0070] Note that the dashed line shown in FIG. 7 indicates the period during which the light L is irradiated. The irradiation device 100 preferably does not irradiate the light L during the first period TA1 and irradiates the light L during the second period TB1. Also, the irradiation device 100 preferably does not irradiate the light L during the third period TA2 and irradiates the light L during the fourth period TB2.

[0071] [Oscillation pattern] Next, the oscillation pattern of the first oscillating part 21 due to the application of the drive signal will be described. FIG. 8 is a graph for explaining the uniaxial oscillation pattern of the optical part.

[0072] As shown in FIG. 8, the rocking pattern of the first rocking part 21 refers to the displacement angle (angle around the first rocking axis AX) of the first rocking part 21 at each time when a drive signal is applied to the first actuator 25. In FIG. 8, the rocking pattern is shown by a solid line.

[0073] In the first period TA1, the drive signal changes in current value from the first current value A1 to the second current value A2. As a result, in the first period TA1, the displacement angle of the first rocking part 21 changes from the first angle D1 to the second angle D2. Here, the intermediate position 0 between the first angle D1 and the second angle D2 is the position where the displacement angle of the first rocking part 21 becomes 0.

[0074] In the second period TB1, the drive signal has its current value held at the second current value A2. As a result, in the second period TB1, the displacement angle of the first rocking part 21 is held at the second angle D2. Note that being held at the second angle D2 is not limited to the displacement angle not changing strictly from the second angle D2, and may also include the displacement angle deviating within a predetermined value range from the second angle D2. The predetermined value here may be set arbitrarily, for example, it may be a value of 10% of the second angle D2.

[0075] In the third period TA2, the drive signal changes in current value from the second current value A2 to the first current value A1. As a result, in the third period TA2, the displacement angle of the first rocking part 21 changes from the second angle D2 to the first angle D1.

[0076] In the fourth period TB2, the drive signal has its current value held at the first current value A1. As a result, in the fourth period TB2, the displacement angle of the first rocking part 21 is held at the first angle D1. Note that being held at the first angle D1 is not limited to the displacement angle not changing strictly from the first angle D1, and may also include the displacement angle deviating within a predetermined value range from the first angle D1. The predetermined value here may be set arbitrarily, for example, it may be a value of 10% of the first angle D1.

[0077] Note that the light L is irradiated in the second period TB1 and the fourth period TB2. Therefore, in the second period TB1, the light L is irradiated onto the first swing part 21 held at the second angle D2, and the optical path of the light L becomes the first position. In the fourth period TB2, the light L is irradiated onto the first swing part 21 held at the first angle D1, and the optical path of the light L shifts to the second position, causing the image to shift by half a pixel.

[0078] In the optical path control device 10 that swings the optical member 20 to shift the optical path, it is required to swing the optical member 20 stably. In the first embodiment, by setting the lengths of the first period TA1 and the third period TA2 to values corresponding to the natural frequency of the first swing part 21, in the second period TB1 and the fourth period TB2, the first swing part 21 can be prevented from vibrating and the first swing part 21 can be swung stably. That is, since the lengths of the first period TA1 and the third period TA2 are values corresponding to the natural frequency of the first swing part 21, the vibration of the first swing part 21 in the second period TB1 and the fourth period TB2 can be suppressed, and the first swing part 21 can be swung stably. Therefore, the first swing part 21 can be swung at high speed and stably stopped, suppressing image degradation.

[0079] Here, the drive signal applied from the drive circuit 16 to the actuator 12B has been described for the drive signal applied to the first actuator 25. Since the same applies to the drive signal applied to the second actuator 26, the description is omitted.

[0080] [Operation of pixels by the optical path control mechanism] Hereinafter, the operation when the first swing part 21 and the second swing part 22 are swung will be described. FIG. 9 is an explanatory diagram for explaining the two-axis swing pattern of the optical unit.

[0081] In the optical path control mechanism 12 of the first embodiment, the first actuator 25 and the second actuator 26 that constitute the actuator 12B cause the first swing part 21 and the second swing part 22 to swing so as to repeat the posture change from the first angle D1 to the second angle D2 and the posture change from the second angle D2 to the first angle D1 around the first shaft part AX and the second shaft part BX in response to drive signals, respectively. By repeating the swing between the first angle D1 and the second angle D2 by the first swing part 21 and the second swing part 22, respectively, the optical axis of the light L repeats the shift from the first position to the second position and the shift from the second position to the first position.

[0082] That is, the image projected on the screen by the light L when the optical axis is at the first position and the image projected on the screen by the light L when the optical axis is at the second position are shifted by half a pixel. That is, the image projected on the screen repeats shifting by half a pixel and then returning by half a pixel. As a result, the apparent number of pixels increases, and the image projected on the screen can be made to have a higher resolution. Since 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 at which the image can be shifted by half a pixel. Note that the shift amount of the image is not limited to half a pixel, and may be arbitrary, such as 1 / 4 or 1 / 8 of a pixel, for example. The first angle D1 and the second angle D2 may also be appropriately set according to the shift amount of the image.

[0083] The following will be described in detail. Here, the direction of the first swing axis AX and the direction of the second swing axis BX intersect in an orthogonal direction and are parallel to the pixel array direction. As shown in FIGS. 3 and 9, the image position P0 is the display position when the current values applied to the first actuator 25 and the second actuator 26 are set to 0, that is, when the displacement angle of the optical member 20 is 0. The A operation state is such that the optical member 20 is swung by a predetermined angle around the first swing axis AX by the first actuator 25, and the image position P0 is shifted by 1 / 4 pixel in the direction of the second swing axis BX. At the same time, the optical member 20 is swung by a predetermined angle around the second swing axis BX by the second actuator 26, and the image position P0 is shifted by 1 / 4 pixel in the direction of the first swing axis AX. That is, in the A operation state, the image is displayed at the image position P1 where the image position P0 is shifted to one ABXa in the ABX direction obtained by synthesizing the vector in one direction in the first swing axis AX direction and the vector in one direction in the second swing axis BX direction.

[0084] Similarly, in the B operation state, the image is displayed at the image position P2 where the image position P0 is shifted to one ABXb in the ABX direction obtained by synthesizing the vector in one direction in the first swing axis AX direction and the vector in one direction in the second swing axis BX direction. Similarly, in the C operation state, the image is displayed at the image position P3 where the image position P0 is shifted to one ABXc in the ABX direction obtained by synthesizing the vector in one direction in the first swing axis AX direction and the vector in one direction in the second swing axis BX direction. Similarly, in the D operation state, the image is displayed at the image position P4 where the image position P01 is shifted to one ABXd in the ABX direction obtained by synthesizing the vector in one direction in the first swing axis AX direction and the vector in one direction in the second swing axis BX direction.

[0085] The swing patterns of the first swing part 21 and the second swing part 22 in the above-described pixel operation states will be described. FIG. 10 is a graph for explaining a two-axis swing pattern when the natural frequencies of the first shaft part and the second shaft part are different, and FIG. 11 is a graph for explaining a two-axis swing pattern when the natural frequencies of the first shaft part and the second shaft part are the same.

[0086] In the following description, the rocking pattern of the first rocking part 21 refers to the displacement angle (angle around the first rocking axis AX) of the first rocking part 21 at each time when a drive signal is applied to the first actuator 25, and is indicated by a solid line. Further, the rocking pattern of the second rocking part 22 refers to the displacement angle (angle around the second rocking axis BX) of the second rocking part 22 at each time when a drive signal is applied to the second actuator 26, and is indicated by a dotted line.

[0087] As shown in FIG. 10, in the displacement period TA2-A, the drive signal changes in current value from the second current value A2 to the first current value A1 (see FIG. 7). Thereby, in the displacement period TA2-A, the displacement angle of the first rocking part 21 changes from the second angle D2 to the first angle D1. In the displacement period TA2-B, the drive signal changes in current value from the second current value A2 to the first current value A1. Thereby, in the displacement period TA2-B, the displacement angle of the second rocking part 22 changes from the second angle D2 to the first angle D1.

[0088] Further, in the displacement period TA1-C, the drive signal changes in current value from the first current value A1 to the second current value A2. Thereby, in the displacement period TA1-C, the displacement angle of the first rocking part 21 changes from the first angle D1 to the second angle D2. In the displacement period TA1-D, the drive signal changes in current value from the first current value A1 to the second current value A2. Thereby, in the displacement period TA1-D, the displacement angle of the second rocking part 22 changes from the first angle D1 to the second angle D2.

[0089] The displacement periods TA2-A, TA2-B, TA1-C, and TA1-D respectively represent the periods of transitioning to the A operating state, B operating state, C operating state, and D operating state described in FIG. 9. When the natural frequencies of the first shaft portion 23 and the second shaft portion 24 are different, for example, since the lengths of the displacement periods TA2-A and TA2-B are different, the lengths of the display periods TB2-A and TB2-B when maintaining the current are different, the appearance of the image in the A operating state and the B operating state is different, and the image quality deteriorates. The same applies to the C operating state and the D operating state. On the other hand, as shown in FIG. 11, when the natural frequencies of the first shaft portion 23 and the second shaft portion 24 are the same, since the lengths of the displacement periods TA2-A and TA2-B are the same, the lengths of the display periods TB2-A and TB2-B when maintaining the current are the same, the appearance of the image in the A operating state and the B operating state is the same, and the deterioration of the image quality is suppressed.

[0090] In the first embodiment, when the optical member 20 is swung in two axes, the torsional rigidity of the second shaft portion 24, which is the center of the swing axis with the larger moment of inertia of the optical member 20, is made higher than the torsional rigidity of the first shaft portion 23, which is the center of the swing axis with the smaller moment of inertia of the optical member 20. Then, the natural frequencies of the first swing portion 21 and the second swing portion 22 are approximated (the same), the lengths of the displacement periods TA1-C and TA2-A of the first swing portion 21 and the lengths of the displacement periods TA1-D and TA2-B of the second swing portion 22 become the same, and the deterioration of the image can be suppressed.

[0091] As described above, in the optical path control mechanism 12 that secondarily swings the optical member 20, the lengths of the displacement periods TA1-C and TA2-A of the first swinging part 21 and the lengths of the displacement periods TA1-D and TA2-B of the second swinging part 22 are made the same to suppress image degradation. In this case, the natural frequencies of the first swinging part 21 and the second swinging part 22 become the same. This displacement time is proportional to the natural frequencies of the respective swinging parts 21 and 22. When the natural frequency increases, the displacement time becomes shorter (the displacement speed increases), and when the natural frequency decreases, the displacement time becomes longer (the displacement speed decreases). And when the natural frequencies of the first swinging part 21 and the second swinging part 22 overlap with an odd multiple (odd number) of the frame rate, each of the swinging parts 21 and 22 causes unnecessary vibration due to resonance, and the optical member 20 cannot be stably stopped.

[0092] Therefore, in the optical path control device 10 of the first embodiment, the natural frequencies of the first swinging part 21 and the second swinging part 22 are set to values shifted from the values of odd multiples of the corresponding frame rate.

[0093] Specifically, the natural frequencies of the first swinging part 21 and the second swinging part 22 are set to values in a range that is greater than an odd integer (n) of the corresponding frame rate and less than an odd integer (n + 2) of the corresponding frame rate.

[0094] The optical path control mechanism 12 swings the first swinging part 21 and the second swinging part 22 by applying a driving signal having a trapezoidal waveform (trapezoidal wave) to the first actuator 25 and the second actuator 26 by the driving circuit 16. This trapezoidal wave can be represented by the sum of trigonometric functions by performing Fourier series expansion. The mathematical formula of this trigonometric function can be represented by a fundamental wave and odd harmonics as follows and can be an approximate formula of the trapezoidal wave shown in FIG. 7. F(x)=(4 / π)×{sin(x)+(1 / 4)×sin(3x) +(1 / 10)×sin(5x)+(1 / 25)×sin(7x)} Therefore, when the odd harmonic component overlaps with the natural frequency, the vibrations of the first swinging part 21 and the second swinging part 22 increase. This has been demonstrated even when actually operating and measuring.

[0095] The displacement time of the first swinging part 21 and the second swinging part 22 is proportional to the natural frequencies of the first swinging part 21 and the second swinging part 22. When the natural frequencies of the first swinging part 21 and the second swinging part 22 overlap with an odd integer multiple of the frame rate, the first swinging part 21 and the second swinging part 22 generate unwanted vibrations due to resonance, and the optical member 20 cannot be stably stationary. Therefore, in the first embodiment, the natural frequencies of the first swinging part 21 and the second swinging part 22 are set to be as large as possible and deviate from the frequencies that are odd integer multiples of the frame rate.

[0096] That is, the natural frequencies of the first swinging part 21 and the second swinging part 22 are set between the same frame rate × n (odd) and frame rate × (n + 2), and satisfied for all corresponding frame rates. Frame rate × n (odd) < Natural frequency < Frame rate × (n + 2)

[0097] The display device 1 has a plurality of frame rates set. Therefore, it is preferable to set the natural frequencies of the first swinging part 21 and the second swinging part 22 to deviate from the values that are odd integer multiples of the corresponding plurality of frame rates.

[0098] For example, when corresponding to three types of frame rates 60Hz, 50Hz, and 48Hz, the natural frequencies of the first swinging part 21 and the second swinging part 22 are set to frequencies that satisfy the following three conditions. 180Hz (60×3) < Natural frequency < 300Hz (60×5) 250Hz (50×5) < Natural frequency < 350Hz (50×7) 240Hz (48×5) < Natural frequency < 336Hz (48×7) That is, the natural frequencies of the first swinging part 21 and the second swinging part 22 are within the following ranges. 250 Hz < natural vibration frequency < 300 Hz

[0099] As described above, in the optical path control device 10 of the first embodiment, the natural vibration frequencies of the first swinging part 21 and the second swinging part 22 are set to values deviated from the values that are odd integer multiples of the corresponding frame rate. Therefore, unnecessary vibrations due to resonance of the first swinging part 21 and the second swinging part 22 can be suppressed, and the optical member 20 can be stably stationary.

[0100] <Second Embodiment> FIG. 12 is a cross-sectional view showing an optical path control mechanism according to the second embodiment, and FIG. 13 is a block diagram schematically showing the circuit configuration of the display device. Note that members having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0101] In the second embodiment, as shown in FIGS. 12 and 13, an optical path control mechanism 12, a control circuit 14, and a drive circuit 16 are provided.

[0102] The optical path control mechanism 12 includes a swinging part 12A including an optical member 20 and an actuator 12B that swings the swinging part 12A. The swinging part 12A includes a first swinging part 21 and a second swinging part 22. The first swinging part 21 swings with respect to the second swinging part 22 by a first shaft part 23 along the first swing axis AX. The second swinging part 22 swings with respect to the support part 27 by a second shaft part 24 along the second swing axis BX. The actuator 12B includes a first actuator 25 and a second actuator 26. The first actuator 25 swings the first swinging part 21, and the second actuator 26 swings the second swinging part 22.

[0103] The optical path control mechanism 12 swings the first swinging part 21 and the second swinging part 22 by driving the first actuator 25 and the second actuator 26 by the drive circuit 16. The drive circuit 16 swings the first swinging part 21 and the second swinging part 22 by applying a trapezoidal drive signal to the first actuator 25 and the second actuator 26.

[0104] The natural frequencies of the first swinging part 21 and the second swinging part 22 are set to predetermined values as described in the first embodiment. The optical path control device 10 sets the length of each displacement period based on the natural frequencies of the first swinging part 21 and the second swinging part 22, and sets a trapezoidal wave of a drive signal so that the current value changes during the displacement period of the set length.

[0105] By the way, the parameters of the drive circuit 16 including the trapezoidal wave of the drive signal are adjusted in advance and then mounted on the product. However, for example, due to variations in the attachment of the optical path control mechanism 12 and the optical path control device 10 to the display device 1, such as installation variations, changes over time, and environmental changes, the natural frequency of the vibrating part may change. In this case, it becomes difficult to readjust the trapezoidal wave of the drive signal.

[0106] Therefore, in the second embodiment, a vibration sensor is mounted on the optical path control device 10, and the trapezoidal wave of the drive signal is adjusted and set based on the vibration frequencies of the first swinging part 21 and the second swinging part 22 detected by the vibration sensor. Note that the waveform of the drive signal is not limited to a trapezoidal shape, and may be a stepped shape, a rectangular shape, or the like.

[0107] That is, the optical path control device 10 includes a vibration sensor 17 and a parameter setting unit 18 in addition to the optical path control mechanism 12, the control circuit 14, and the drive circuit 16.

[0108] The vibration sensor 17 is attached to the support part 27. The vibration sensor 17 can detect the vibration frequencies of the first swinging part 21 and the second swinging part 22 as the swinging part 12A. The parameter setting unit 18 adjusts and sets the trapezoidal wave of the drive signal applied by the drive circuit 16 to the first actuator 25 and the second actuator 26 based on the vibration frequencies of the first swinging part 21 and the second swinging part 22 detected by the vibration sensor 17.

[0109] That is, the drive circuit 16 applies (sweeps) a sine wave to the first actuator 25 while gradually increasing the frequency from 0 Hz. At this time, the vibration sensor 17 disposed on the support portion 27 measures the vibration of the first swinging portion 21. Then, based on the vibration of the first swinging portion 21 detected by the vibration sensor 17, the parameter setting unit 18 sets the frequency at which the first swinging portion 21 vibrates most greatly (resonates) as the natural frequency of the first swinging portion 21.

[0110] Similarly, the drive circuit 16 applies (sweeps) a sine wave to the second actuator 26 while gradually increasing the frequency from 0 Hz. At this time, the vibration sensor 17 disposed on the support portion 27 measures the vibration of the second swinging portion 22. Then, based on the vibration of the second swinging portion 22 detected by the vibration sensor 17, the parameter setting unit 18 sets the frequency at which the second swinging portion 22 vibrates most greatly (resonates) as the natural frequency of the second swinging portion 22.

[0111] The control circuit 14 sets the trapezoidal wave of the drive signal, that is, the length of the displacement period, based on the natural frequencies of the respective swinging portions 21 and 22 set by the parameter setting unit 18. Then, the control circuit 14 sets the trapezoidal wave of the drive signal so that the current value changes during the set displacement period.

[0112] As described above, in the optical path control device 10 of the second embodiment, the vibration sensor 17 is mounted on the optical path control device 10. The vibration sensor 17 detects the natural frequencies of the first swinging portion 21 and the second swinging portion 22, and the parameter setting unit 18 adjusts and sets the waveform of the drive signal based on the vibration frequencies of the first swinging portion 21 and the second swinging portion 22 detected by the vibration sensor 17. Therefore, even if the natural frequency of the vibrating portion changes due to variations in the attachment of the optical path control mechanism 12 or the optical path control device 10 to the display device 1, changes over time, environmental changes, etc., it is possible to easily adjust the drive waveform (trapezoidal wave) for swinging the first swinging portion 21 and the second swinging portion 22 at the time of shipment of the display device 1. Also, even if the natural frequency shifts due to aging deterioration of the constituent members after the shipment of the display device 1, it is possible to adjust the drive waveforms (trapezoidal waves) of the first swinging portion 21 and the second swinging portion 22 when necessary.

[0113] (Effect) As described above, the optical path control device according to the present embodiment includes a swing unit 12A having an optical member (optical unit) 20 into which light is incident, an actuator 12B that swings the swing unit 12A, and a first period in which the current value is changed and a second period in which the current value is held. A drive circuit 16 that controls the optical path of the light transmitted through the optical member 20 by swinging the swing unit 12A by applying a drive signal having a waveform including a period to the actuator 12B, a vibration sensor 17 that detects the vibration frequency of the swing unit 12A, and a parameter setting unit 18 that sets a drive signal having a waveform based on the vibration frequency of the swing unit 12A detected by the vibration sensor 17.

[0114] According to the optical path control device of the present embodiment, the vibration sensor 17 detects the vibration frequency of the swing unit 12A, and the parameter setting unit 18 sets a drive signal having a waveform based on the vibration frequency of the swing unit 12A, so that the optical member 20, the swing unit, and the actuator 12B can be adjusted at any time. The deviation of the waveform of the drive signal according to the mounting positions of the component members such as the above can be adjusted. Therefore, the waveform of the drive signal for driving the actuator 12B can be automatically adjusted to reduce the man-hours.

[0115] Further, the optical path control device according to the present embodiment is provided with a first swing unit 21 that supports the optical member 20 and a second swing unit 22 that swingably supports the first swing unit 21 as the swing unit 12A. The second swing unit 22 is swingably supported by the support unit 27, and the natural vibration frequency of the first swing unit 21 and the natural vibration frequency of the second swing unit 22 are set to fall within a predetermined range set in advance. Therefore, resonance (unnecessary vibration) of the first swing unit 21 and the second swing unit 22 can be suppressed, and the optical member 20 can be stably stationary.

[0116] Further, the optical path control device according to the present embodiment mounts the vibration sensor on the support unit 27. Therefore, the natural vibration frequencies of the first swing unit 21 and the second swing unit 22 can be detected with high accuracy by the vibration sensor 17.

[0117] In addition, the display device according to the present embodiment includes an optical path control device 10 and an irradiation device 100 that irradiates the swinging portion 12A with light L. By including the optical path control device 10, the display device 1 can stably swing the swinging portion 12A and suppress image degradation.

[0118] In the above-described embodiment, the optical member 20 is configured to be swingably supported by the first shaft portion 23 along the first swing axis AX and also swingably supported by the second shaft portion 24 along the second swing axis BX. However, the configuration is not limited thereto. The optical member 20 may be configured to be swingably supported by one axis instead of two intersecting axes, or may be configured to be swingably supported by three or more intersecting axes.

[0119] Although the optical path control device 10 according to the present invention has been described so far, it may be implemented in various different forms other than the above-described embodiments.

[0120] Each component of the illustrated optical path control device 10 is a functional concept, and does not necessarily have to be physically configured as illustrated. That is, the specific form of each device is not limited to that shown in the figure, and all or part of it may be functionally or physically dispersed or integrated in any unit according to the processing load of each device, the usage situation, and the like.

[0121] The configuration of the optical path control device 10 is realized, for example, as software by a program loaded into a memory or the like. In the above embodiment, it has been described as a functional block realized by the cooperation of these hardware or software. That is, these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

[0122] The above-described components include those that can be easily assumed by those skilled in the art and substantially the same ones. Furthermore, the above-described configurations can be combined as appropriate. Also, various omissions, substitutions, or changes in the configuration are possible without departing from the gist of the present invention.

Explanation of Reference Numerals

[0123] 1 represents a device 10 Optical path control device 12 Optical path control mechanism 12A Swing part 12B Actuator 14 Control circuit 16 Drive circuit (drive part) 17 Vibration sensor 18 Parameter setting part 20 Optical member (optical part) 21 First swing part 22 Second swing part 23 First shaft part 24 Second shaft part 25 First actuator 26 Second actuator 27 Support part 31 First movable part 32 Second movable part 41, 44 Coil 42, 45 Yoke 43, 46 Magnet 100 Irradiation device AX First swing axis BX Second swing axis

Claims

1. A swinging part having an optical part for light incidence, An actuator for swinging the swinging part, A driving part that controls the optical path of light transmitted through the optical part by swinging the swinging part by applying a driving signal having a waveform including a first period for changing the current value and a second period for holding the current value to the actuator, A vibration sensor for detecting the vibration frequency of the swinging part, A parameter setting part for setting the natural vibration frequency of the swinging part based on the vibration frequency of the swinging part detected by the vibration sensor, A control part for setting the driving signal of the waveform based on the natural vibration frequency set by the parameter setting part, An optical path control device comprising:

2. The swinging part has a first swinging part that supports the optical part and a second swinging part that swingably supports the first swinging part, and the second swinging part is swingably supported by a support part, The natural vibration frequency of the first swinging part and the natural vibration frequency of the second swinging part are set so as to fall within a predetermined range set in advance, The optical path control device according to Claim 1.

3. The vibration sensor is attached to the support part, The optical path control device according to Claim 2.

4. The optical path control device according to any one of Claims 1 to 3, An irradiation device for irradiating light to the optical part, A display device comprising:

Images