Optical path-changing device and projection image display device

Abstract

To provide an optical path-changing device capable of driving with low noise, and a projection image display device using the same.SOLUTION: The optical path-changing device includes: a light transmission part that transmits light; at least two actuators each have a movable part whose movement is controlled in one axis direction; an arm having elasticity with one end connected with the moving part of the actuator and the other end connected with the light transmission part; and a control unit that controls the reciprocating drive of the actuator at a specific cycle. The control unit is configured to control the actuator so as to drive the light transmission part to stop when the actuator stops when controlling the drive of the actuator from a position of maximum displacement on one side to the position of maximum displacement on the other in the reciprocating drive.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an optical path changing device and a projection-type image display device including the same. [Background technology]

[0002] Patent Document 1 discloses an optical member drive control device that changes the optical path of an incident light beam by tilting a parallel plate glass. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 098120 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for higher resolution projected images, and optical path changing devices that can be driven at higher speeds are desired. However, the faster the drive speed, the greater the drive force required, which increases the vibration transmitted to the housing that supports the optical path changing device, and can result in loud noise.

[0005] An object of the present disclosure is to provide an optical path changing device that can be driven with less noise, and a projection-type image display device that uses the same. [Means for solving the problem]

[0006] The optical path changing device of the present disclosure includes a light-transmitting portion that transmits light, at least two actuators having a movable portion that is controlled to move in one axial direction, an elastic arm having one end connected to the movable portion of the actuator and the other end connected to the light-transmitting portion, and a control unit that drives and controls the actuator to reciprocate at a specific period. When driving and controlling the actuator from one position of maximum displacement amount to the other position of maximum displacement amount in the reciprocating drive, the control unit drives and controls the actuator so that the light-transmitting portion comes to a standstill when the actuator stops.

[0007] The projection-type image display device of the present disclosure includes the above-described optical path changing device. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide an optical path changing device that can be driven with less noise, and a projection-type image display device that uses the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an overall view showing the configuration of a projection-type image display device according to an embodiment of the present invention; [Figure 2A] A perspective view of a projection lens unit attached to a projection-type image display device. [Figure 2B] FIG. 1 is a perspective view of a projection lens unit removed from a projection-type image display device; [Figure 2C] 1 is a cross-sectional view of an optical path changing device, a projection lens unit, and an optical chassis according to an embodiment of the present invention; [Figure 3] 1 is a perspective view of an optical path changing device according to an embodiment of the present invention; [Figure 4] 1 is a side view of a light transmitting portion and an arm according to an embodiment of the present invention; [Figure 5] FIG. 1 is a block diagram showing the structure of an optical path changing device according to an embodiment. [Figure 6] FIG. 10 is an explanatory diagram illustrating the amount of movement of a light transmitting portion in the embodiment. [Figure 7] FIG. 10 is an explanatory diagram illustrating the amount of movement of a light transmitting portion in a comparative example. [Figure 8]10 is a graph showing the displacement of a movable portion and the displacement of an end portion of a light transmitting member in an embodiment. [Figure 9] Graph showing displacement of the position of the movable part in the embodiment [Figure 10] Graph showing displacement of the end position of a light transmitting member in an embodiment. [Figure 11] Graph showing displacement of the position of the movable part in a comparative example [Figure 12] Graph showing displacement of the end position of the light transmitting member in the comparative example [Figure 13A] An explanatory diagram illustrating the initial position of the actuator [Figure 13B] FIG. 1 is an explanatory diagram illustrating the driving operation of the actuator 105. [Figure 14] FIG. 10 is an explanatory diagram illustrating the driving operation of the actuator when it is in the first position. [Figure 15] FIG. 10 is an explanatory diagram illustrating the driving operation of the actuator in the second position. [Figure 16] FIG. 10 is an explanatory diagram illustrating the driving operation of the actuator in the third position. [Figure 17] FIG. 10 is an explanatory diagram illustrating the driving operation of the actuator in the fourth position. [Figure 18A] FIG. 10 is an explanatory diagram illustrating the initial position of an actuator in a modified example. [Figure 18B] FIG. 10 is an explanatory diagram illustrating the driving operation of the actuator in a modified example. [Figure 19A] Graph showing waveforms of actuator drive control [Figure 19B] Graph showing waveforms of actuator drive control [Figure 20] An explanatory diagram showing the simulation model [Figure 21] Table showing odd multiples of the fundamental frequency [Figure 22] An explanatory diagram showing odd multiples of the fundamental frequency DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of well-known matters or redundant explanation of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0011] The inventor(s) provide the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and do not intend for them to limit the subject matter described in the claims.

[0012] (Embodiment) Hereinafter, an embodiment will be described with reference to Fig. 1. Fig. 1 is an overall view for explaining the configuration of an optical system of a projection-type image display device 200 equipped with an optical path changing device 100 of the present disclosure. In the following description, an X1Y1Z1 Cartesian coordinate system is set as shown in Fig. 1.

[0013] [1-1. Overall structure] The laser light source is composed of multiple blue semiconductor lasers 301 to realize a high-brightness lighting device. The laser light emitted from each blue semiconductor laser 301 is collimated by a corresponding collimator lens 302. The light emitted from collimator lens 302 becomes approximately parallel light, and the entire light beam is collected by condenser lens 303. After passing through diffuser plate 304, the light is again approximately parallelized by lens 305. The laser light beam approximately parallelized by lens 305 enters dichroic mirror 306, which is positioned at approximately 45 degrees to the optical axis.

[0014] Diffusion plate 304 is a flat glass plate, and one side of it has a diffusing surface with fine irregularities formed thereon. Dichroic mirror 306 has the property of reflecting light in the wavelength range of blue semiconductor laser 301 and transmitting light in other wavelength ranges.

[0015] The laser light incident on dichroic mirror 306 in the -X1 direction is reflected by dichroic mirror 306 and emitted in the -Z1 direction. The laser light is then condensed by condenser lenses 307 and 308 and excites the phosphor formed on phosphor wheel 320.

[0016] Phosphor wheel 320 has segments on which red and green phosphors are formed in the circumferential direction on a disk-shaped substrate, and further has openings as light-transmitting regions.

[0017] Red light and green light obtained from the red phosphor and green phosphor of phosphor wheel 320 are emitted from phosphor wheel 320. These red light and green light are approximately parallelized by condenser lenses 308 and 307, transmitted through dichroic mirror 306, condensed by condenser lens 317, and incident on rod integrator 318.

[0018] On the other hand, the blue light from blue semiconductor laser 301 that passes through the opening of phosphor wheel 320 travels via lens 309, lens 310, mirror 311, lens 312, mirror 313, lens 314, mirror 315, and lens 316, is reflected by dichroic mirror 306, and is collected by collecting lens 317 before entering rod integrator 318. Lenses 312, 314, and 316 function as relay lenses.

[0019] Light emitted from rod integrator 318 passes through lenses 330, 331, and 332 and enters total reflection prism 335, which is made up of a pair of prisms 333 and 334. DMD (Digital Mirror Device) 336, which is a light modulation element, modulates the incident light with a video signal and emits it as image light. Lenses 330 and 331 are relay lenses, and lens 332 has the function of forming an image of the light from the exit surface of rod integrator 318 on DMD 336.

[0020] The image light emitted from the DMD 336 is incident on the light transmitting member 101a arranged in the optical path changing device 100. The light transmitted through the light transmitting member 101a is incident on the projection lens unit 337, and the light emitted from the projection lens unit 337 is enlarged and projected onto the screen as image light.

[0021] The optical path changing device 100 can move the display position of the image light by tilting the light transmitting member 101a with respect to the optical axis AL. This function allows the projection-type image display device 200 to perform wobbling display. Here, wobbling display is a method of displaying different images while shifting the display position multiple times during one frame period of the input image, thereby equivalently improving the resolution of the displayed image, and is also called pixel shift display. The drive control device 110 (see FIG. 5) drives the actuator 105 with a control signal synchronized with the drive of the DMD 336.

[0022] Next, the attachment and detachment of the projection lens unit 337 to the projection image display device 200 will be described with reference to Figures 2A, 2B, and 2C. Figure 2A is a perspective view of the projection lens unit attached to the projection image display device. Figure 2B is a perspective view of the projection lens unit detached from the projection image display device. Figure 2C is a cross-sectional view of the optical path changing device 100, the projection lens unit 337, and the optical chassis 338. In Figure 2 and subsequent figures, an XYZ Cartesian coordinate system is set so that the direction of the optical axis AL is the Z-axis direction and the plane perpendicular to the Z-axis direction is the XY plane.

[0023] The projection lens unit 337 has a projection lens 337a that enlarges and projects incident image light. The projection lens unit 337 is detachable from an optical chassis 338, which is part of the case of the projection-type image display device 200. The projection lens 337a is attached to a projection lens mounter 337b, and the projection lens mounter 337b is attached to the optical chassis 338. The optical path changing device 100 is attached to the optical chassis 338. As shown in FIG. 2C , the light-transmitting unit 101 of the optical path changing device 100 and the projection lens 337a are arranged on the optical axis AL. The optical path changing device 100 is arranged in a narrow space between the projection lens 337a and other optical components in the optical chassis 338.

[0024] [1-2. Optical path changing device] Next, the main configuration of the optical path changing device 100 will be described in detail with reference to Fig. 3. Fig. 3 is a perspective view of the appearance of the optical path changing device 100.

[0025] The optical path changing device 100 includes a light transmitting section 101, an arm 103, a first actuator 105A, a second actuator 105B, a third actuator 105C, a fourth actuator 105D, and a position detecting element 107.

[0026] The light-transmitting unit 101 transmits light while shifting it on the optical axis AL and parallel to the optical axis AL. The light-transmitting unit 101 includes a light-transmitting member 101a and a support frame 101b. The light-transmitting member 101a is a member through which image light passes, such as parallel flat glass. The support frame 102 has rigidity and supports the outer periphery of the light-transmitting member 101a. The support frame 101b has, for example, a substantially square outer periphery, and four arms 103 are connected to the four corners of the support frame 101b, each of which is rounded to form a hypotenuse. The light-transmitting unit 101 can tilt in a direction intersecting the optical axis AL by driving the arms 103 in the direction of the optical axis AL by an actuator 105.

[0027] Each of the actuators 105A, 105B, 105C, and 105D reciprocates the connected arm 103 in one axial direction, for example, along the optical axis AL. In the following description, when a common description is given to the actuators 105A to 105D, they will be simply referred to as actuator 105. The actuator 105 uses, for example, a voice coil motor (VCM).

[0028] The arm 103 supports the light transmitting portion 101 and drives the connection portion with the light transmitting portion 101 in the direction of the optical axis AL. The arm 103 is formed of an elastic material. The material used for the arm 103 has elasticity that allows the angle at the bending portion to be displaced by an external factor and tends to return to the original angle when the movement of the actuator 105 is reversed. Therefore, the arm 103 has greater elasticity due to bending and warping than elasticity due to expansion and contraction. The arm 103 is, for example, a SUS304-based or SUS301-based material. The SUS304-based or SUS301-based material is a type of steel classified as austenitic stainless steel. The thickness of the arm 103 is, for example, 0.1 mm or more and 0.5 mm or less.

[0029] Arm 103 has first bent portion 103a, second bent portion 103b, and third bent portion 103c, each formed by bending a plate-like member at three locations. Arm 103 also has first plate-like portion 103d, second plate-like portion 103e, third plate-like portion 103f, and fourth plate-like portion 103g, which extend linearly.

[0030] One end of the first bent portion 103a is connected to the light transmitting portion 101 via the second plate-shaped portion 103e, and the other end of the first bent portion 103a is connected to one end of the first plate-shaped portion 103d. One end of the second bent portion 103b is connected to the actuator 105 via the third plate-shaped portion 103f, and the other end of the second bent portion 103b is connected to the third bent portion 103c via the fourth plate-shaped portion 103g. The third plate-shaped portion 103f is fixed to the upper end of the actuator 105, for example, by a screw. One end of the third bent portion 103c is connected to one end of the first plate-shaped portion 103d.

[0031] The first bent portion 103a, the second bent portion 103b, and the third bent portion 103c have elasticity that changes with the bending angle. The first plate-shaped portion 103d, the second plate-shaped portion 103e, the third plate-shaped portion 103f, and the fourth plate-shaped portion 103g have elasticity that changes with warping and twisting. Therefore, the first bent portion 103a, which is the first elastic portion, and the first plate-shaped portion 103d, which is the second elastic portion, have different elastic moduli.

[0032] Of the four arms 103, the arms 103 in one set are arranged so as to be perpendicular to the arms 103 in the other set. In each set of arms 103, two arms 103 are arranged so as to face each other.

[0033] Position detection element 107 is attached to movable part 106, and detects the position of the part of arm 103 to which actuator 105 is attached from the amount of movement of movable part 106. Position detection element 107 detects the position of arm 103 from the amount of movement of movable part 106, which reciprocates inside actuator 105.

[0034] Next, the configuration of the control system of the optical path changing device 100 will be described with reference to Fig. 5. The optical path changing device 100 further includes a drive control device 110 that controls the drive of each actuator 105, a drive waveform generation circuit 111 that generates drive waveforms for each actuator, and a drive timing generation circuit 113.

[0035] The drive timing generation circuit 113 generates timing signals for generating respective drive waveforms corresponding to each actuator 105 based on a synchronization signal input that is synchronized with the input image signal and has the period of the input image signal.

[0036] The drive waveform generating circuit 111 uses a timing signal for generating a drive waveform supplied from the drive timing generating circuit 113 to generate a drive waveform corresponding to each actuator 105 in synchronization with an externally input image signal. Therefore, the drive waveform indicates an ideal amount of displacement of the movable part 106. Each generated drive waveform is sent to the corresponding drive control device 110.

[0037] The drive control device 110 performs feedback control of the drive amount of each actuator 105 based on the position signal input from the position detection element 107 in accordance with the received drive waveform. A control method, for example, PID control, is used. This drives each actuator 105, displacing the portion of each connected arm 103 connected to the movable portion 106 that reciprocates inside the actuator 105. This displacement is transmitted through the arm 103 to displace the light transmitting portion 101. In this way, the movement of the light transmitting portion 101 relative to the optical axis is controlled. The drive control device 110 can be configured, for example, with a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, or an ASIC. The drive control devices 110 corresponding to each actuator 105 may be integrated into a single control device.

[0038] Next, the function of the first bent portion 103a of the arm 103 will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is an explanatory diagram illustrating the amount of movement of the light transmitting portion in the embodiment. Fig. 7 is an explanatory diagram illustrating the amount of movement of the light transmitting portion in the comparative example.

[0039] In the embodiment, the distance from the central axis of the light-transmitting portion 101 to the end of the support frame 101b of the light-transmitting portion 101 is defined as La, and the distance from the central axis of the light-transmitting portion 101 to the movable portion 106 of the actuator 105 is defined as Lb. As an example, a case where La:Lb=1:2 will be described. In the embodiment, the arm 103 connected to the light-transmitting portion 101 has a first bent portion 103a near a connection point P1 connected to the light-transmitting portion 101. As a result, the relationship between the movement amount L1 of the connection point P1 between the arm 103 and the light-transmitting portion 101 and the movement amount L2 of the movable portion 106 along the optical axis AL is L1:L2=1.4:2. In other words, since L1 / L2>La / Lb, the movement amount of the connection point P1 can be increased.

[0040] In contrast, in the comparative example shown in FIG. 7, the arm 103Z connected to the light-transmitting portion 101 does not have a bent portion near the connection point P1 where the arm 103Z is connected to the light-transmitting portion 101, and the plate-like portion in the center of the arm 103Z extends directly to connect to the light-transmitting portion 101. In this configuration, the angle θ between the arm 103Z and the light-transmitting portion 101 is the same. The relationship between the movement amount L3 of the connection point P1 between the arm 103Z and the light-transmitting portion 101 and the movement amount L2 of the movable portion 106 along the optical axis AL is L3:L2=1:2. In other words, since L3 / L2=La / Lb, the movement amount of the connection point P1 is smaller than in the embodiment. Here, the first bent portion 103a being located near the connection point P1 means, for example, that the second plate-like portion 103e has a length of less than one-tenth of the total length of the arm 103 or a length of less than 5 mm.

[0041] Thus, according to the embodiment, arm 103 has first bent portion 103a near connection point P1 connected to light transmitting portion 101, and the elasticity of the bent shape allows connection point P1 with light transmitting portion 101 to move more along the direction of optical axis AL. This is because when movable portion 106 moves, first bent portion 103a of interlocking arm 103 bends, thereby bending arm 103, and therefore, a movement of connection point P1 different from the amount of movement of movable portion 106 occurs, as shown in Fig. 8. Fig. 8 is a graph showing displacement PV1 of movable portion 106 and displacement PV2 of the end of light transmitting member 101a in the embodiment.

[0042] When the amount of movement of the movable part 106 is small, the inertial force due to the mass of the light transmitting part 101 causes the arm 103 to bend, preventing connection point P1 from moving, and as the amount of movement of the movable part 106 increases further, the light transmitting part 101 is accelerated by the spring force caused by the bending of the arm 103 and starts to move, moving at high speed until it reaches a distance greater than the amount of movement of the movable part 106, after which it is decelerated by the spring force caused by the arm 103 bending in the opposite direction and stops moving. This type of movement allows the light transmitting part 101 of the embodiment to be displaced at higher speeds.

[0043] Fig. 9 is a graph showing the actual displacement of movable part 106 according to the embodiment, Fig. 10 is a graph showing the actual displacement of the end of light transmitting member 101a according to the embodiment, Fig. 11 is a graph showing the actual displacement of movable part 106 according to the comparative example, and Fig. 12 is a graph showing the actual displacement of the end of light transmitting member 101a according to the comparative example.

[0044] As shown in FIGS. 9 and 10, in the embodiment, when the movable portion 106 is displaced by approximately 0.1 mm in 1.7 msec, the end of the light transmitting member 101a is displaced by approximately 0.07 mm in 0.8 msec. In contrast, in the conventional example, as shown in FIG. 11, when the movable portion 106 is displaced by approximately 0.1 mm in 1.7 msec, the end of the light transmitting member 101a is displaced by 0.05 mm in approximately 0.8 to 1.7 msec. Thus, even when the movable portion 106 is moved by the same amount of displacement, the end of the light transmitting member 101a is displaced by a larger amount of displacement in the embodiment than in the comparative example, and can be displaced in a shorter time. Furthermore, as shown in FIG. 10, in the embodiment, the first bending portion 103a is used as the first elastic portion, and therefore, the vibration of the end of the light transmitting member can be converged more quickly than when, for example, a coil spring is used.

[0045] Next, an example of the driving operation of the four actuators 105 will be described with reference to Fig. 13A to Fig. 17. Fig. 13A is an explanatory diagram showing the initial positions of the actuators 105. Fig. 13B is a table showing the driving positions of the actuators 105. Figs. 14 to 17 are explanatory diagrams each explaining the driving operation of the actuators 105.

[0046] 13A, two axes, which are obtained by moving a line connecting the opposing actuators 105 in parallel to the center of gravity of the light-transmitting portion 101, are defined as orthogonal axes by two sets of actuators 105, and the position of the intersection of these lines does not move up, down, left, or right. To achieve this movement, the actuators 105 are driven and controlled so that the light-transmitting portion 101 rotates around two rotation axes Ra1 and Ra2.

[0047] The drive control device 110 cooperatively controls the four actuators 105, for example, so that the movable parts 106 of two of the four actuators 105 are sequentially actuated in either of the adjacent directions. As shown in FIG. 13B, the four actuators 105A to 105D are cooperatively controlled to four states, Position 1 to Position 4, in addition to the initial position, Position 0. In FIG. 13B, for the four actuators 105A to 105D, "0" indicates the center position, "+1" indicates a position elevated in the Z-axis direction, and "-1" indicates a position lowered in the Z-axis direction. FIG. 13A shows the state in which the four actuators 105 are in their initial positions at Position 0. When light is not projected in pixel shift mode, the actuators 105 are not driven and light is transmitted in Position 0.

[0048] 14 shows the state of the four actuators 105 at position 1. The second actuator 105B retracts the movable part 106, and the fourth actuator 105D drives the movable part 106 to protrude. As a result, the first actuator 105A and the second actuator 105B do not protrude their respective movable parts 106, and the third actuator 105C and the fourth actuator 105D drive their respective movable parts 106 to protrude, pushing out the corresponding arms 103 in the direction of the optical axis AL.

[0049] 15 shows the state of the four actuators 105 at position 2. The third actuator 105C retracts the movable part 106, and the first actuator 105A drives the movable part 106 to protrude. As a result, the second actuator 105B and the third actuator 105C do not protrude their respective movable parts 106, and the fourth actuator 105D and the first actuator 105A drive their respective movable parts 106 to protrude, pushing out the corresponding arms 103 in the direction of the optical axis AL.

[0050] 16 shows the state of the four actuators 105 at position 3. The fourth actuator 105D retracts the movable part 106, and the second actuator 105B drives the movable part 106 to protrude. As a result, the third actuator 105C and the fourth actuator 105D do not protrude their respective movable parts 106, and the first actuator 105A and the second actuator 105B drive their respective movable parts 106 to protrude, pushing out the corresponding arms 103 in the direction of the optical axis AL.

[0051] 17 shows the state of the four actuators 105 at position 4. The first actuator 105A retracts the movable part 106, and the third actuator 105C drives the movable part 106 to protrude. As a result, the fourth actuator 105D and the first actuator 105A do not protrude their respective movable parts 106, and the second actuator 105B and the third actuator 105C drive their respective movable parts 106 to protrude, pushing out the corresponding arms 103 in the direction of the optical axis AL.

[0052] Next, as shown in Fig. 14, the state of the four actuators 105 returns to position 1. The first actuator 105A retracts the movable part 106, and the third actuator 105C drives the movable part 106 to protrude it. In this way, by each drive control device 110 driving and controlling the corresponding actuator 105 so that adjacent actuators 105 operate in either direction in turn, the tilt state of the light transmitting member 101a with respect to the optical axis AL can be changed one after another, and the transmitted light can be shifted to four positions in turn.

[0053] 18A, the two rotation axes Ra1 and Ra2 may be rotated 45 degrees around the optical axis from the above example and set in the extending direction of each arm 103. In this case, as shown in FIG. 18B, the four actuators 105A to 105D may be cooperatively controlled to four different states, positions 5 to 9, in addition to the initial position of position 0.

[0054] In this way, by controlling the four actuators 105 in a coordinated manner, the direction of light travel can be shifted in two axial directions, the horizontal and vertical directions, thereby achieving more precise and faster pixel shift control.

[0055] The above has described the coordinated drive control of the four actuators 105. Next, the drive control of each actuator 105 will be described with reference to Fig. 5 and Figs. 19A, 19B, and 20. First, the drive waveform of the actuator 105 generated by the drive waveform generation circuit 111 will be described. Note that in Figs. 19A and 19B, time is shown as time normalized by the period T.

[0056] The drive timing generation circuit 113 shown in Fig. 5 generates a drive timing signal as shown in Fig. 19A(b) based on a synchronization signal having a period T of an externally input video signal as shown in Fig. 19A(a). Fig. 19A(a) shows a synchronization signal having a period T. The synchronization signal is a repeating timing signal having a period T. Fig. 19A(b) shows a drive timing signal generated by the drive timing generation circuit 113. The drive timing generation circuit 113 generates a drive timing signal that is a time-series timing signal based on the synchronization signal with the period T.

[0057] The drive waveform generating circuit 111 shown in Fig. 5 generates a control target position signal for the actuator 105 as shown in Fig. 19A(c). Fig. 19A(c) shows the target signal for the actuator position generated by the drive waveform generating circuit 111.

[0058] The drive control device 110 in Fig. 5 compares the output of the position detection element 107 with the actuator position target signal shown in Fig. 19A(c) and generates an acceleration force for the actuator 105 as shown in Fig. 19A(d). Fig. 19A(d) shows the acceleration force for the actuator 105.

[0059] By integrating the graph of the acceleration force of the actuator 105 in (d) of FIG. 19A, a graph of the velocity of the actuator 105 shown in (e) of FIG. 19A can be obtained. (e) of FIG. 19A shows the velocity of the actuator 105. By further integrating the graph of (e) of FIG. 19A, a graph of the position of the actuator 105 shown in (f) of FIG. 19A can be obtained. The control target position signal of the actuator 105 shown in (c) of FIG. 19A and the position of the actuator 105 shown in (f) of FIG. 19A are controlled to be equal by a configuration in the drive control device 110 that compares the output of the position detection element 107 with the actuator position target signal shown in (c) of FIG. 19A and generates an acceleration force of the actuator 105 shown in (d) of FIG. 19A. (f) of FIG. 19A shows the waveform of the position of the actuator 105.

[0060] The light transmitting portion 101 can be considered to have an inertial force M and to be connected to an arm 103 having an elastic modulus D. The waveform representing the relationship between the displacement amount of the light transmitting portion 101 and the displacement amount of the actuator 105 is shown in FIG. 19B (g).

[0061] FIG. 19B(h) shows a graph of the difference between the position of the actuator 105 shown in FIG. 19A(f) and the position of the light-transmitting portion 101 based on the simulation results shown in FIG. 19B(g). The difference between the position of the actuator 105 and the position of the light-transmitting portion 101 corresponds to the distortion of the actuator 105. An acceleration force proportional to the difference between the position of the actuator 105 and the position of the light-transmitting portion 101 is generated in the light-transmitting portion 101. The velocity of the light-transmitting portion 101 shown in FIG. 19B(i) is determined by integrating this acceleration force over time. Furthermore, integrating the graph in FIG. 19B(i) results in the graph of the position of the light-transmitting portion 101 shown in FIG. 19B(g). When creating the waveform in FIG. 19A(c), the waveform in FIG. 19A(c) can be finely modified with reference to the waveform in FIG. 19B(g) obtained by simulation, thereby further improving accuracy.

[0062] The transition time Tt of the actuator position target shown in (c) of FIG. 19A is set according to a time constant determined from the inertial force M and elastic modulus D of the light transmitting portion 101. This transition time Tt is controlled by a transition time adjustment value input by the user. The transition time adjustment value is adjusted to a value that does not cause overshoot or undershoot in the waveform by observing the waveform at the light transmitting portion position corresponding to (g) of FIG. 19A of an actual device. The repetition period T of the drive waveform is the repetition period of the input synchronization signal. The transition time Tt is constant regardless of the period of the input synchronization signal, and the time Ti at which the actuator 105 stops changes according to the period of the input synchronization signal.

[0063] The transition time adjustment value input to the drive waveform generating circuit 111 and the drive timing generating circuit 113 is a value that corrects variations in the elastic modulus of the arms 103 of the four actuators 105. The transition time adjustment value is a value that sets the time Tt from when the actuator 105 starts to move until it stops.

[0064] Furthermore, the fundamental frequency of the video signal is input to the drive timing generation circuit 113. The fundamental frequencies are 48, 50, and 60 Hz. Based on the input fundamental frequency, the time Ti at which the actuator 105 stops is determined.

[0065] The drive waveform generating circuit 111 and the drive timing generating circuit 113 generate the target position waveform of the actuator 105 in Fig. 19(c) so that the speed of the light transmitting portion 101 becomes zero at time Ti when the actuator 105 stops, as shown in Fig. 19(f). The drive control device 110 controls the drive of the actuator 105 by, for example, PID control, so that the target actuator position waveform and the detection value from the position detecting element 107 become equal.

[0066] Next, the target resonance frequency will be described with reference to Figures 21 and 22. The resonance frequency of the optical path changing device 100 is determined by a time constant determined by the inertial force M, which is determined by the shape and weight of the light transmitting section 101, and the elastic modulus D, which is determined by the material, width, thickness, and shape of the arm 103. The target resonance frequency is set so as to avoid being an odd multiple of the frequency of the input synchronization signal, and the light transmitting section 101 and the arm 103 are designed to achieve the set resonance frequency. The frequency of the input synchronization signal can be, for example, 48, 50, or 60 Hz, and Figure 21 shows odd multiples of these frequencies.

[0067] When these odd-number multiple frequencies are lined up as shown in Figure 22, there are some areas where the difference between adjacent frequencies is large. For example, between 350 and 420 Hz, between 420 and 528 Hz, and between 550 and 624 Hz. By setting intermediate frequencies between these adjacent frequencies, 385 Hz, 474 Hz, and 587 Hz, as the target resonant frequency, it is possible to avoid the resonant frequency matching odd-number multiples of 48, 50, and 60 Hz, which are the frequencies of the input synchronization signal, even if the resonant frequency varies due to variations in the inertial force M and the elastic modulus D. This prevents unnecessary vibrations from occurring in the light-transmitting portion 101.

[0068] [1-3. Effects, etc.] As described above, the optical path changing device 100 according to this embodiment includes the light transmitting portion 101 that transmits light, at least two actuators 105 each having a movable portion 106 that is controlled to move in the direction of the optical axis AL, and the arm 103 having one end connected to the movable portion 106 of the actuator 105 and the other end connected to the light transmitting portion 101. The optical path changing device 100 further includes a drive control device 110 that controls the reciprocating drive of the actuator 105 at a specific period. When driving and controlling the actuator 105 from one position of maximum displacement amount to the other position of maximum displacement amount in the reciprocating drive, the drive control device 110 controls the drive of the actuator 105 so that the light transmitting portion 101 comes to a standstill at the timing when the actuator 105 stops.

[0069] In the optical path changing device 100 according to this embodiment, the speed at which the end face of the light transmitting portion 101 moves is greater than the speed at which the movable portion 106 of the actuator 105 moves. Therefore, when the required speed is set for the tilting speed of the light transmitting portion 101, it is possible to reduce the moving speed of the movable portion 106. The operating noise generated during operation of the optical path changing device 100 is generated by a force generated as a reaction to the force that drives the light transmitting portion 101 or the movable portion 106 of the actuator 105, and increases in proportion to the square of the speed at which the object moves. In the optical path changing device 100 of the present invention, the only part that operates at high speed is the light transmitting portion 101, so it is possible to reduce this operating noise.

[0070] The optical path changing device 100 also includes a drive waveform generating circuit 111 that generates drive waveforms for each actuator 105, and a position detecting element 107 that detects the position of the actuator 105. The drive control device 110 compares the drive waveform generated by the drive waveform generating circuit 111 with the detected value of the position detecting element 107, and controls the drive of the actuator 105 so that the drive waveform and the detected value become equal. When driving and controlling the actuator 105 from one position of maximum displacement to the other position of maximum displacement in its reciprocating drive, the drive waveform generating circuit 111 generates a drive waveform such that the light transmitting portion 101 comes to a standstill at the timing when the actuator 105 stops.

[0071] The arm 103 has a first bending portion 103a as a first elastic portion and a first plate-shaped portion 103d as a second elastic portion, which have different elastic moduli, and the arm 103 has the first bending portion 103a as the first elastic portion on the light-transmitting portion 101 side thereof, and the arm has the first plate-shaped portion 103d as the second elastic portion in the central portion thereof.

[0072] In the arm 103, the first bending portion 103a is located closer to the light-transmitting portion 101 than the first plate-shaped portion 103d in the center, so that the light-transmitting portion 101 can be displaced to a value close to the displacement amount of the movable portion 106 of the actuator 105, and it becomes possible to reduce the displacement amount of the movable portion 106 of the actuator 105, and it becomes possible to reduce the operating speed and reduce operating noise.

[0073] The arm 103 also has a second bent portion 103b, one end of which is connected to the actuator 105 via a third plate-shaped portion 103f, and a third bent portion 103c, one end of which is connected to the other end of the first plate-shaped portion 103d and the other end of which is connected to the other end of the second bent portion 103b via a fourth plate-shaped portion 103g.

[0074] In this way, by having a plurality of bent portions in the arm 103, the optical path changing device 100 can be arranged without interference even in a small space in the projection lens unit 337.

[0075] (Other embodiments) As described above, the above-described embodiments have been described as examples of the technology in the present disclosure. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the above-described embodiments to create new embodiments.

[0076] In the above-described embodiment, the first bent portion 103a is formed as the first elastic portion in the arm 103, but this is not limiting. For example, the first elastic portion may be a plate-like portion having a width smaller than that of the first plate-like portion 103d. Even with this configuration, the first elastic portion has a greater elastic modulus than the first plate-like portion 103d serving as the second elastic portion, and the same effect as in the embodiment can be obtained.

[0077] In the above-described embodiment, the optical path changing device 100 includes four arms 103, but is not limited to this. The optical path changing device 100 may include two, three, or five or more arms 103. Furthermore, the optical path changing device 100 is not limited to four actuators 105, and may include actuators 105 in a number corresponding to the number of arms 103.

[0078] As described above, the embodiments have been described as examples of the technology of the present disclosure. For this purpose, the accompanying drawings and detailed description have been provided. Therefore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the above technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately indicating that these non-essential components are essential.

[0079] Furthermore, since the above-described embodiments are intended to illustrate the technology of the present disclosure, various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[0080] (Outline of the embodiment) (1) The optical path changing device of the present disclosure includes a light-transmitting portion that transmits light, at least two actuators each having a movable portion that is controlled to move in one axial direction, an elastic arm having one end connected to the movable portion of the actuator and the other end connected to the light-transmitting portion, and a control unit that controls the actuator to reciprocate at a specific period. The control unit controls the actuator to be driven so that the light-transmitting portion comes to a standstill when the actuator stops, when the actuator is driven and controlled to reciprocate from one position of maximum displacement to the other position of maximum displacement.

[0081] The control unit controls the drive of the actuator so that the light transmitting portion comes to a standstill when the actuator stops. As a result, in the light path changing device according to this embodiment, the speed at which the end face of the light transmitting portion moves is greater than the speed at which the movable portion of the actuator moves. Therefore, when the required speed is set for the tilting speed of the light transmitting portion, it is possible to reduce the moving speed of the movable portion. The operating noise generated during operation of the light path changing device is generated by a force generated as a reaction to the force that drives the light transmitting portion or the movable portion of the actuator, and increases in proportion to the square of the speed at which the object moves. In the light path changing device of the present invention, the only part that moves at high speed is the light transmitting portion, so it is possible to reduce this operating noise.

[0082] (2) The optical path changing device of (1) further includes a drive waveform generating circuit that generates drive waveforms for each actuator and a position detecting element that detects the position of the actuator. The control unit compares the drive waveform generated by the waveform generating unit with the detected value of the position detecting element, and controls the drive of the actuator so that the drive waveform and the detected value are equal. When driving and controlling the actuator from one position of maximum displacement to the other position of maximum displacement in reciprocating drive, the waveform generating unit generates a drive waveform that causes the light transmitting portion to stop when the actuator stops.

[0083] (3) In the optical path changing device of (2), the drive waveform generating circuit adjusts the time of the drive waveform from when the actuator starts to move until when it stops, based on the transition time set according to the time constant determined by the inertial force of the light transmitting section and the elastic modulus of the arm.

[0084] (4) In the optical path changing device of (2) or (3), the resonance frequency determined by the time constant determined by the inertial force of the light transmitting portion and the elastic modulus of the arm is set so as not to be an odd multiple of the synchronization signal.

[0085] (5) In any one of the optical path changing devices (1) to (4), the arm has a first elastic portion and a second elastic portion having different elastic moduli, the first elastic portion being on the light transmitting portion side of the arm, and the second elastic portion being in the central portion of the arm.

[0086] (6) In the optical path changing device of (5), the first elastic part is a first bent part where the arm is bent, and the second elastic part is a first plate-like part where the arm extends linearly. One end of the first bent part is connected to the light transmitting part via the second plate-like part, and the other end of the first bent part is connected to one end of the first plate-like part.

[0087] (7) In the optical path changing device of (5), the arm has a second bent portion having one end connected to the actuator via a third plate-shaped portion, and a third bent portion having one end connected to the other end of the first plate-shaped portion and the other end connected to the other end of the second bent portion via a fourth plate-shaped portion.

[0088] (8) In the optical path changing device of (6), the arm is made of a SUS304 or SUS301 material.

[0089] (9) The projection-type image display device of the present disclosure includes any one of the optical path changing devices (1) to (8). [Industrial Applicability]

[0090] The present disclosure is applicable to a projection display device that displays an image while changing the display positions of pixels. [Explanation of symbols]

[0091] 100 Optical path changing device 101 Light transmission part 101a Light-transmitting member 101b support frame 103 Arm 103a first bend 103b Second bend 103c Third bend 103d First plate-shaped portion 103e Second plate-shaped portion 103f Third plate-shaped part 103g Fourth plate 105 Actuator 105A First Actuator 105B Second Actuator 105C Third Actuator 105D 4th Actuator 106 Moving parts 107 Position detection element 109 Position detection circuit 110 Drive control device 111 Drive waveform generation circuit 200 Projection-type image display device 337 Projection Lens Unit 337a Projection lens 338 Optical Chassis AL optical axis L1, L2, L3 travel amount P1 connection point PV1, PV2 displacement

Claims

1. a light transmitting portion that transmits light; At least two actuators each having a movable part whose movement is controlled in one axial direction; an elastic arm having one end connected to the movable portion of the actuator and the other end connected to the light transmitting portion; a control unit that controls the actuator to reciprocate at a specific cycle; a drive waveform generating circuit for generating a drive waveform that is a position target waveform for each of the actuators; a position detection element for detecting a position of the actuator, the control unit compares the drive waveform generated by the drive waveform generation circuit with the detection value of the position detection element, and controls the drive of the actuator so that the position of the actuator on the drive waveform is equal to the detection value; the drive waveform generation circuit adjusts the time of the drive waveform from when the actuator starts to move until when it stops, based on a transition time that is set according to a value determined from the inertial force of the light transmitting portion and the elastic modulus of the arm, and that is adjusted using a transition time adjustment value that corrects for variations in the elastic modulus of the arm. Optical path changing device.

2. the drive waveform generation circuit generates a drive waveform that causes the light transmitting portion to stop at a timing when the actuator stops, when controlling the actuator to drive from one position of maximum displacement to the other position of maximum displacement in the reciprocating drive.

2. The optical path changing device according to claim 1.

3. a resonance frequency determined by a value determined from the inertial force of the light transmitting portion and the elastic modulus of the arm is set so as not to be an odd multiple of a synchronization signal; 3. The optical path changing device according to claim 2.

4. the arm has a first elastic portion and a second elastic portion having different elastic moduli, the first elastic portion being located on the light transmitting portion side of the arm, and the second elastic portion being located around the center of the arm; 3. The optical path changing device according to claim 1.

5. the first elastic portion is a first bending portion where the arm is bent, the second elastic portion is a first plate-shaped portion from which the arm extends linearly, one end of the first bent portion is connected to the light transmitting portion via a second plate-shaped portion, and the other end of the first bent portion is connected to one end of the first plate-shaped portion; 5. The optical path changing device according to claim 4.

6. the arm includes a second bent portion, one end of which is connected to the actuator via a third plate-shaped portion; a third bent portion having one end connected to the other end of the first plate-shaped portion and the other end connected to the other end of the second bent portion via a fourth plate-shaped portion; 6. The optical path changing device according to claim 5.

7. The arm is made of a SUS304 or SUS301 material.

6. The optical path changing device according to claim 5.

8. An optical path changing device according to any one of claims 1 to 7, Projection-type image display device.

Images