Optical path changing device and projection-type image display device provided with same

Abstract

This optical path changing device has: an optical member; a first support member for supporting the optical member; a second support member for supporting the first support member to be capable of swinging about a first swing center line; a base member for supporting the second support member to be capable of swinging about a second swing center line; a first actuator disposed to one side of the first swing center line, the first actuator causing the first support member to swing; and a second actuator disposed to one side of the second swing center line, the second actuator causing the second support member to swing. Either the first swing center line is shifted toward the first actuator with respect to the center of the shape of the optical member, or the second swing center line is shifted toward the second actuator with respect to the center of the shape of the optical member.

Description

Optical path changing device and projection type image display device equipped with the same

[0001] The present disclosure relates to an optical path changing device that drives an optical member to shift the projection position of image light, and a projection-type image display device including the same.

[0002] For example, Patent Document 1 discloses an optical path changing device that is mounted on a projection image display device and shifts the image projected on a screen by changing the orientation of an optical member through which image light passes.

[0003] International Publication No. 2015 / 098120

[0004] However, in the case of Patent Document 1, four actuators are used to change the position of the optical member, and therefore, high-level noise is generated from the actuators while the position of the optical member is being changed.

[0005] Therefore, an object of the present disclosure is to reduce the noise level generated when changing the position of an optical member in an optical path changing device of a projection type image display device.

[0006] In order to solve the above-mentioned problems, according to one aspect of the present disclosure, there is provided an optical path changing device comprising: an optical element; a first support member that supports the optical element; a second support member that supports the first support member so that it can swing about a first swing center line that extends in a direction intersecting the propagation direction of light incident on the optical element; a base member that supports the second support member so that it can swing about a second swing center line that extends in a direction intersecting the propagation direction and is different from the first swing center line; a first actuator that is arranged on one side of the first swing center line as viewed in the propagation direction and swings the first support member; and a second actuator that is arranged on one side of the second swing center line as viewed in the propagation direction and swings the second support member, wherein the first swing center line is shifted toward the first actuator with respect to the geometric center of the optical element as viewed in the propagation direction, or the second swing center line is shifted toward the second actuator with respect to the geometric center of the optical element as viewed in the propagation direction.

[0007] Furthermore, according to another aspect of the present disclosure, there is provided an optical path changing device comprising: an optical element; a support element supporting the optical element; a base element supporting the support element so that it can swing about a swing center line extending in a direction intersecting the propagation direction of light incident on the optical element; and an actuator arranged on one side of the swing center line when viewed in the propagation direction, which swings the support element, wherein the swing center line is shifted toward the actuator with respect to the geometric center of the optical element when viewed in the propagation direction.

[0008] Furthermore, according to another aspect of the present disclosure, there is provided a projection type image display device having the above-mentioned optical path changing device, a light source, and an optical modulation module that converts light from the light source into image light and emits the image light toward the optical element of the optical path changing device.

[0009] According to the present disclosure, in an optical path changing device of a projection type image display device, it is possible to reduce the noise level generated when changing the position of an optical member.

[0010] 1 is a schematic configuration diagram of an example of a projection type image display device equipped with an optical path changing device according to an embodiment of the present disclosure; 2 is a diagram for explaining driving of an optical element by the optical path changing device; 3 is a top view of the optical path changing device; 4 is a partial cross-sectional view of the optical path changing device in a state where image light is transmitted; 5 is an exploded perspective view of the optical path changing device; 6 is a top view of the movable unit;

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0012] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0013] Hereinafter, an optical path changing device and a projection type image display device according to an embodiment of the present disclosure will be described with reference to the drawings.

[0014] 1 is a schematic diagram of an example of a projection-type image display device equipped with an optical path changing device according to an embodiment of the present disclosure. Note that the X-Y-Z Cartesian coordinate system shown in FIG. 1 is intended to facilitate understanding of the embodiment of the present disclosure and is not intended to limit the present disclosure. In the X-Y-Z Cartesian coordinate system, the X-axis direction indicates the width direction of the image projected by the projection-type image display device, the Y-axis direction indicates the height direction of the image, and the Z-axis direction indicates the projection direction of the projection-type image display device.

[0015] 1, the projection-type image display device 10 is a so-called projector and includes a housing 12, a light source 14, a light modulation module 16 that converts light L from the light source 14 into image light Lm based on image data, and a projection lens 18 that projects the image light Lm onto a screen S. The light modulation module 16 is composed of, for example, a plurality of DMDs (digital micromirror devices) (not shown) and TIR prisms (total internal reflection prisms) (not shown). Note that the present disclosure does not limit the light modulation module that converts light L into image light Lm.

[0016] The projection type image display device 10 also has an optical path changing device 20. The optical path changing device 20 includes an optical member 22 disposed between the light modulation module 16 and the projection lens 18.

[0017] The projection type image display device 10 has optical components (not shown) such as mirrors, prisms, and filters between the light source 14 and the light modulation module 16, and between the light modulation module 16 and the optical component 22 of the optical path changing device 20.

[0018] In such a projection-type image display device 10, the light modulation module 16 converts the light L from the light source 14 into image light Lm, and emits the image light Lm toward the optical member 22 of the optical path changing device 20. The image light Lm passes through the optical member 22 and the projection lens 18, and is projected onto the screen S. As a result, an image is displayed on the screen S.

[0019] FIG. 2 is a diagram for explaining the driving of the optical members by the optical path changing device.

[0020] 2, the optical member 22 of the optical path changing device 20 is located between the light modulation module 16 and the projection lens 18, and includes an incident surface 22a onto which the image light Lm from the light modulation module 16 is incident, and an exit surface 22b from which the image light Lm is emitted toward the projection lens 18. The incident surface 22a and the exit surface 22b are flat surfaces parallel to each other.

[0021] The optical path changing device 20 drives the optical element 22 so that the optical element 22 swings about a first swing center line CL1 extending in a direction (X-axis direction in this embodiment) intersecting the propagation direction of the image light Lm incident on the optical element 22 (Z-axis direction in this embodiment). The optical path changing device 20 also drives the optical element 22 so that the optical element 22 swings about a second swing center line CL2 extending in a direction (Y-axis direction in this embodiment) intersecting the propagation direction of the image light Lm incident on the optical element 22 and different from the first swing center line CL1. This driving changes the attitude of the optical element 22. In this embodiment, the propagation direction of the image light Lm incident on the optical element 22 is the extension direction of the optical axis LA of the projection lens 18. When viewed from the propagation direction, the first swing center line CL1 and the second swing center line CL2 are orthogonal to each other.

[0022] When the optical path changing device 20 drives the optical member 22, the image M projected on the screen S is shifted in both the width direction W (X-axis direction) and the height direction H (Z-axis direction) by a stroke range of 1 / 2 pixel. In the present embodiment, when the optical member 22 swings around the first swing center line CL1, the image M moves back and forth in the height direction H. Furthermore, when the optical member 22 swings around the second swing center line CL2, the image M moves back and forth in the width direction W.

[0023] By driving the optical member 22, an image M that is shifted by +1 / 4 pixel in the width direction and +1 / 4 pixel in the height direction from the reference position, an image M that is shifted by +1 / 4 pixel in the width direction and -1 / 4 pixel in the height direction from the reference position, an image M that is shifted by -1 / 4 pixel in the width direction and -1 / 4 pixel in the height direction from the reference position, and an image M that is shifted by -1 / 4 pixel in the width direction and +1 / 4 pixel in the height direction from the reference position are projected onto the screen S in this order. Note that the reference position is the position when the optical member 22 is not driven (i.e., is in a stopped state), and is the position when the image light Lm from the light modulation module 16 is incident perpendicularly on the incident surface 22a of the optical member 22. As a result, the image M is displayed on the screen S with a higher resolution than the original image data.

[0024] In order to increase the resolution of the image M on the screen S in this way, the optical path changing device 20 needs to drive the optical member 22 at high speed. To achieve this, the optical path changing device 20 has the following configuration.

[0025] Fig. 3 is a perspective view of the optical path changing device, Fig. 4 is a top view of the optical path changing device, and Fig. 5 is an exploded perspective view of the optical path changing device.

[0026] 3 to 5, the optical path changing device 20 has a main unit 24 that supports the optical member 22, and a base member 26 that rotatably supports the main unit 24. In addition, in the case of this embodiment, the optical path changing device 20 has a flexible printed circuit board 28 and a spacer member 30 that supports the flexible printed circuit board 28.

[0027] 3 and 4 , in this embodiment, the optical member 22 is a disk-shaped member made of transparent parallel plate glass. When the optical member 22 is in the reference position, the image light Lm from the light modulation module 16 is incident on the incident surface 22a of the optical member 22 at a right angle. When the optical member 22 is in the reference position, the center P0 of the shape of each of the incident surface 22a and the exit surface 22b is located on the optical axis LA of the projection lens 18, and the incident surface 22a and the exit surface 22b are each perpendicular to the optical axis LA. When the optical member 22 is in the reference position, the image M on the screen S is located at the reference position.

[0028] The main unit 24 is made up of a plurality of members and is a unit that supports the optical member 22 .

[0029] Fig. 6 is a top view of the main unit, and Fig. 7 is an exploded perspective view of the main unit.

[0030] The main unit 24 includes a sub-unit 32. The sub-unit 32 includes a first support member 34 that supports the optical member 22.

[0031] 6 and 7 , in this embodiment, the first support member 34 is a frame-like member that supports the outer edge of the optical member 22. The shape of the first support member 34 is not important as long as it can support the optical member 22. For example, the first support member 34 may be U-shaped.

[0032] The main unit 24 also includes a second support member 36 that supports the subunit 32 so that the subunit 32 can swing about a first swing center line CL1.

[0033] In the present embodiment, the second support member 36 is a frame-shaped member and includes a through-hole 36a that accommodates the subunit 32. The thickness (size in the Z-axis direction) of the second support member 36 is approximately equal to the thickness of the subunit 32. This reduces the thickness of the main unit 24. As a result, the optical path changing device 20 is made thinner, and the distance between the light modulation module 16 in which the optical path changing device 20 is disposed and the projection lens 18 can be reduced. The shape of the second support member 36 is not important as long as it can support the subunit 32 in a swingable manner.

[0034] In this embodiment, the second support member 36 supports the subunit 32 so that it can swing via two leaf spring members 38. The leaf spring members 38 are made of a deformable elastic material. For example, the leaf spring members 38 are made by pressing a thin metal plate.

[0035] As shown in FIG. 6 , the two leaf spring members 38 are spaced apart in the direction in which the first oscillation center line CL1 extends (the X-axis direction) when viewed from above (the Z-axis direction). The subunit 32 is disposed between the two leaf spring members 38 when viewed from above. Each leaf spring member 38 includes a first fixed portion 38a fixed to the first support member 34 of the subunit 32, a second fixed portion 38b fixed to the second support member 36, and a deformable, elongated connecting portion 38c connecting the first fixed portion 38a and the second fixed portion 38b. The first fixed portion 38a and the second fixed portion 38b face each other at an interval in the direction in which the first oscillation center line CL1 extends (the X-axis direction), and the connecting portion 38c connecting them extends on the first oscillation center line CL1.

[0036] The connecting portions 38c of the leaf spring members 38 are elastically deformed so as to twist, causing the subunit 32 to swing within the second support member 36 and swing around the first swing center line CL1. Furthermore, when the optical path changing device 20 is in a stopped state, the leaf spring members 38 maintain the optical member 22 in the subunit 32 in the reference position.

[0037] 4 and 5, the main unit 24 is supported by the base member 26 so as to be able to swing about a second swing center line CL2. In this embodiment, the second support member 36 of the main unit 24 is supported by the base member 26 via two leaf spring members 40. The leaf spring members 40 are made of a deformable elastic material. For example, the leaf spring members 40 are made by pressing a thin metal plate.

[0038] As shown in FIG. 4 , the two leaf spring members 40 are spaced apart in the direction in which the second oscillation center line CL2 extends (the Y-axis direction) when viewed from above (the Z-axis direction). The main unit 24 is disposed between the two leaf spring members 40 when viewed from above. Each leaf spring member 40 includes a first fixed portion 40a fixed to the second support member 36 of the main unit 24, a second fixed portion 40b fixed to the base member 26, and a deformable, elongated connecting portion 40c connecting the first fixed portion 40a and the second fixed portion 40b. The first fixed portion 40a and the second fixed portion 40b face each other at an interval in the direction in which the second oscillation center line CL2 extends (the Y-axis direction), and the connecting portion 40c connecting them extends on the second oscillation center line CL2.

[0039] The connecting portions 40c of the leaf spring members 40 are elastically deformed so as to twist, causing the main unit 24 to swing above the base member 26 and swing about the second swing center line CL2. Furthermore, when the optical path changing device 20 is in a stopped state, the leaf spring members 40 maintain the optical member 22 in the main unit 24 in the reference position.

[0040] 3 and 4, the optical path changing device 20 includes a first actuator 42 that swings the subunit 32 about a first swing center line CL1, and a second actuator 44 that swings the main unit 24 about a second swing center line CL2. As shown in FIG. 4, the first actuator 42 is disposed on one side of the first swing center line CL1 when viewed in the direction in which the optical axis LA extends (the Z-axis direction). In this embodiment, the first actuator 42 is housed in a through hole 36a of the second support member 36. The second actuator 44 is disposed on one side of the second swing center line CL2 when viewed in the direction in which the optical axis LA extends.

[0041] Fig. 8 is an exploded perspective view of the first actuator, Fig. 9 is an exploded perspective view of the second actuator, and Fig. 10 is a cross-sectional view of the first and second actuators.

[0042] As shown in FIG. 8, the first actuator 42 is a voice coil type actuator, and includes a coil 46 , a movable magnet 48 , a yoke 50 , and an attachment member 52 .

[0043] The coil 46 is included in the fixed portion 42a of the first actuator 42 and is fixed to the base member 26 as shown in Fig. 5. The coil 46 is open in the direction in which the optical axis LA extends (the Z-axis direction). The coil 46 receives an alternating current from a circuit (not shown) on the flexible printed circuit board 28, for example, to generate an alternating magnetic field that drives the movable magnet 48.

[0044] As shown in FIG. 10 , the movable magnet 48 is attached to a yoke 50 and disposed within the coil 46. The movable magnet 48 and the yoke 50 are included in the movable part 42b of the first actuator 42. When the coil 46 generates an alternating magnetic field, the movable part 42b reciprocates substantially in the direction in which the optical axis LA extends (the Z-axis direction). Note that the movable part 42b is not guided so as to reciprocate precisely in the direction in which the optical axis LA extends.

[0045] The mounting member 52 is an elastically deformable member that connects the movable part 42b of the first actuator 42 and the first support member 34 of the subunit 32. For example, the mounting member 52 is a leaf spring made by pressing a thin metal plate.

[0046] 8 , the mounting member 52 includes a first fixed portion 52a provided in the center and fixed to the yoke 50, a second fixed portion 52b provided at an end and attached to the first support member 34, and a deformable connecting portion 52c connecting the first fixed portion 52a and the second fixed portion 52b. The first support member 34 includes a pair of arm portions 34a spaced apart in the extension direction of the first oscillation center line CL1 (X-axis direction), and each protruding in the extension direction of the second oscillation center line CL2 (Y-axis direction). The second fixed portion 52b of the mounting member 52 is fixed to each of the arm portions 34a. As a result, the movable portion 42b of the first actuator 42 is disposed between the arm portions 34a.

[0047] With this first actuator 42, when the coil 46 generates an alternating magnetic field, the movable part 42b of the first actuator 42 reciprocates substantially in the direction in which the optical axis LA extends (the Z-axis direction). The reciprocating movement of the movable part 42b causes the subunit 32 to oscillate about the first oscillation center line CL1. This causes the optical member 22 to oscillate about the first oscillation center line CL1.

[0048] As shown in FIG. 9, the second actuator 44 is a voice coil type actuator, and like the first actuator 42, includes a coil 54, a movable magnet 56, a yoke 58, and an attachment member 60.

[0049] In this embodiment, the coil 54, the movable magnet 56, and the yoke 58 of the second actuator 44 are substantially the same as the coil 46, the movable magnet 48, and the yoke 50 of the first actuator 42. The coil 54 is included in the fixed portion 44a of the second actuator 44, and the movable magnet 56 and the yoke 58 are included in the movable portion 44b.

[0050] The mounting member 60 connects the movable portion 44b of the second actuator 44 and the second support member 36 of the main unit 24, and is made of an elastic material. For example, the mounting member 60 is made by pressing a thin metal plate.

[0051] As shown in FIG. 9 , the mounting member 60 includes a first fixed portion 60a provided in the center and fixed to the yoke 58, a second fixed portion 60b provided at an end and attached to the second support member 36, and a deformable connecting portion 60c connecting the first fixed portion 60a and the second fixed portion 60b. The second support member 36 includes a pair of arm portions 36b that protrude in the extension direction of the first swing center line CL1 (X-axis direction) and are spaced apart in the extension direction of the second swing center line CL2 (Y-axis direction). The second fixed portion 60b of the mounting member 60 is fixed to each of the arm portions 36b. As a result, the movable portion 44b of the second actuator 44 is disposed between the arm portions 36b.

[0052] With this second actuator 44, when the coil 54 generates an alternating magnetic field, the movable part 44b of the second actuator 44 reciprocates in the direction in which the optical axis LA extends (the Z-axis direction). The reciprocating movement of the movable part 44b causes the main unit 24 to swing about the second swing center line CL2. As a result, the optical member 22 swings about the second swing center line CL2.

[0053] Furthermore, in this embodiment, as shown in Figure 4, the optical path changing device 20 is equipped with a first position sensor 62 for detecting the position of the movable part 42 of the first actuator 42, and a second position sensor 64 for detecting the position of the movable part 44b of the second actuator 44.

[0054] In this embodiment, the first and second position sensors 62, 64 are so-called Hall sensors. The first and second position sensors 62, 64 are composed of position-detecting magnets 62a, 64a and sensing chips (magnetic field detectors) 62b, 64b that detect the magnetic fields generated by the position-detecting magnets 62a, 64a. The position-detecting magnets 62a, 64a are attached to the yokes 50, 58 of the movable parts 42b, 44b of the first and second actuators 42, 44. The sensing chips 62b, 64b are mounted on the flexible printed circuit board 28 and fixed to the base member 26. The first and second position sensors 62, 64 detect the positions of the movable parts 42b, 44b of the first and second actuators 42, 44 (positions in the direction of extension of the optical axis LA (Z-axis direction)) based on changes in the magnetic fields detected by the sensing chips 62b, 64b. Based on the detection results of the first and second position sensors 62, 64, a processor (not shown) such as an MPU of the optical path changing device 20 mounted on the flexible printed circuit board 28 controls the AC current supplied to the coils 46, 54 of the first and second actuators 42, 44.

[0055] So far, we have explained the configuration of the optical path changing device 20. From here on, we will explain some further features of the optical path changing device 20 according to this embodiment.

[0056] First, as shown in FIG. 6 , the first support member 34 of the sub-unit 32 and the movable portion 42b of the first actuator 42 are not directly connected, but are connected via an attachment member 52. Similarly, the second support member 36 of the main unit 24 and the movable portion 44b of the second actuator 44 are not directly connected, but are connected via an attachment member 60. Furthermore, because the attachment members 52 and 60 are made of an elastic material, the two connecting portions 52c and 60c are elastically deformable. In other words, the movable portion 42b of the first actuator 42 of the first support member 34 is connected via a plurality of elastic members (first elastic members), and the second support member 36 and the movable portion 44b of the second actuator 44 are connected via a plurality of elastic members (second elastic members). Such connections via elastic members provide the following effects.

[0057] FIG. 11 is a diagram showing changes in the swing angles of the optical member and the first and second actuators.

[0058] 2, the swing angle θ is the swing angle of the optical element 22 swinging about the first swing center line CL1. The swing angle φ is the swing angle of the optical element 22 swinging about the second swing center line CL2. When the optical element 22 is in the reference posture, the swing angles θ and φ are both zero degrees.

[0059] In this embodiment, the first and second actuators 42, 44 do not swing. However, the swing angles α and β of the first and second actuators 42, 44 can be defined as in the following formulas 1 and 2.

[0060]

[0061]

[0062] In Equation 1, L1 is the distance between the first oscillation center line CL1 and the movable part 42b of the first actuator 42. Note that the distance L1 is the distance when the optical member 22 is in the reference position. d1 is the displacement of the movable part 42b of the first actuator 42 in the extension direction of the optical axis LA (Z-axis direction). Note that when the optical member 22 is in the reference position, the displacement d1 is zero.

[0063] In Equation 2, L2 is the distance between the second oscillation center line CL2 and the movable part 44b of the second actuator 44. Note that the distance L2 is the distance when the optical member 22 is in the reference position. d2 is the displacement of the movable part 44b of the second actuator 44 in the extension direction of the optical axis LA (Z-axis direction). Note that when the optical member 22 is in the reference position, the displacement d2 is zero.

[0064] 11 , when the movable part 42b of the first actuator 42 swings at the maximum swing angle α (displaces by the maximum displacement amount d1) about the first swing center line CL1, the optical element 22 swings at a larger swing angle θ. Similarly, when the movable part 44b of the second actuator 44 swings at the maximum swing angle β (displaces by the maximum displacement amount d2) about the second swing center line CL2, the optical element 22 swings at a larger swing angle φ.

[0065] This behavior occurs due to elastic deformation of the connecting portions 52c, 60c of the mounting members 52, 60. Specifically, when the displacement directions of the movable portions 42b, 44b of the first and second actuators 42, 44 are reversed, the connecting portions 52c, 60c are elastically deformed by inertial force, causing the displacement direction of the optical element 22 to be reversed with a delay. Furthermore, due to the elastic deformation of the connecting portions 52c, 60c, the maximum oscillation angles θ, φ of the optical element 22 become larger than the maximum oscillation angles α, β of the first and second actuators 42, 44. In other words, the amplitudes of the oscillation angles θ, φ of the optical element 22 become larger than the amplitudes of the oscillation angles α, β of the first and second actuators 42, 44.

[0066] Furthermore, elastic deformation of the connecting portions 52c, 60c of the mounting members 52, 60 generates a restoring force at the connecting portions 52c, 60c of the mounting members 52, 60. Due to this restoring force, the speed from zero to peak and the speed from peak to zero are faster for the oscillation angles θ, φ of the optical member 22 than for the oscillation angles α, β of the first and second actuators 42, 44. As a result, even though the amplitudes are different, the frequency of the oscillation angles θ, φ of the optical member 22 and the frequency of the oscillation angles α, β of the first and second actuators 42, 44 are substantially the same.

[0067] Driving the optical member 22 using the first and second actuators 42, 44 in this manner allows the optical member 22 to be driven by a large swing amount with a small displacement of the movable portions 42 b, 44 b of the first and second actuators 42, 44. That is, when driving the optical member 22 at the swing amount and swing speed required to increase the resolution of the image M on the screen S, the displacement amount and displacement speed of the movable portions 42 b, 44 b of the first and second actuators 42, 44 can be reduced (compared to when the movable portions 42 b, 44 b of the first and second actuators 42, 44 are directly connected to the first and second support members 34, 36 without the intermediary of the mounting members 52, 60). As a result, the noise level generated by the first and second actuators 42, 44 when driving the optical member 22 can be reduced.

[0068] 6, in this embodiment, the first support member 34 and the movable portion 42b of the first actuator 42 are preferably connected at multiple locations. That is, the first support member 34 and the first actuator 42 are connected via two connecting portions 52c of the mounting member 52. Furthermore, the two connecting portions 52c are arranged at an interval in the extension direction of the first oscillation center line CL1 (the X-axis direction). This allows the subunit 32 to swing uniformly over the entire extension direction of the first oscillation center line CL1. In contrast, if there were only one connecting portion 52c, the posture of the movable portion 42b of the first actuator 42 would be unstable and prone to tilting, which could prevent the image M on the screen S from being displayed at an appropriate high resolution.

[0069] Furthermore, the extension length of the connecting portion 52c (first elastic member) of the mounting member 52 is preferably greater than the distance between the portion of the first support member 34 connected to the connecting portion 52c and the portion of the first actuator 42. Therefore, the connecting portion 52c extends in a serpentine manner. That is, the connecting portion 52c does not connect the first support member 34 and the first actuator 42 over the shortest length. In contrast, if the connecting portion 52c connects the first support member 34 and the first actuator 42 over the shortest distance, the connecting portion 52c cannot elastically deform to a sufficient degree. In this case, as shown in FIG. 11 , when the movable portion 42b of the first actuator 42 oscillates at the maximum oscillation angle α (displaces by the maximum displacement d1), the effect of oscillating the optical member 22 at a larger oscillation angle θ is small. Therefore, the reduction in the noise level generated by the first actuator 42 is small. Therefore, by providing the connecting portion 52c of the mounting member 52 with an extension length that is greater than the distance between the first support member 34 and the first actuator 42, the noise level generated from the first actuator 42 can be sufficiently reduced.

[0070] 6, the second support member 36 and the movable portion 44b of the first actuator 44 are also connected at multiple locations. That is, the second support member 36 and the second actuator 44 are connected via two connecting portions 60c of the mounting member 60. Furthermore, the two connecting portions 60c are arranged at an interval in the extension direction of the second swing center line CL2 (the Y-axis direction). This allows the main unit 24 to swing uniformly over the entire extension direction of the second swing center line CL2.

[0071] Similarly, the extension length of the connecting portion 60c (second elastic member) of the mounting member 60 is also greater than the distance between the portion of the second support member 36 connected to the connecting portion 60c and the portion of the second actuator 44. In other words, the connecting portion 60c extends in a serpentine manner. This allows the noise level generated by the second actuator 44 to be sufficiently reduced.

[0072] 4 and 6, the first and second oscillation center lines CL1 and CL2 are offset from the geometric center P0 of the optical element 22. Specifically, when viewed in the direction in which the optical axis LA extends (the Z-axis direction), the first oscillation center line CL1 is offset toward the first actuator 42, and the second oscillation center line CL2 is offset toward the second actuator 44. As a result, the first oscillation center line CL1 approaches the first actuator 42, and the second oscillation center line CL2 approaches the second actuator 44. This reduces the required displacement of the movable parts 42b and 44b of the first and second actuators 42 and 44 compared to when the first and second oscillation center lines CL1 and CL2 overlap the geometric center P0 of the optical element 22 when viewed in the direction in which the optical axis LA extends. As a result, the noise level generated by the first actuators 42 and 44 can be reduced.

[0073] At least one of the first and second oscillation center lines CL1 and CL2 may overlap the geometric center P0 of the optical member 22 when viewed in the extending direction of the optical axis LA (Z-axis direction).

[0074] 4 and 6, it is preferable that the first oscillation center line CL1 be closer to the center of gravity G1 of the subunit 32 than to the geometric center P0 of the optical member 22. More preferably, the first oscillation center line CL1 overlaps with the center of gravity G1 of the subunit 32 when viewed in the direction in which the optical axis LA extends (the Z-axis direction). This allows the first actuator 42 to oscillate the subunit 32 about the first oscillation center line CL1 with a smaller force. In this embodiment, the power supplied to the coil 46 of the first actuator 42 can be kept low.

[0075] Similarly, it is preferable that the second oscillation center line CL2 be closer to the center of gravity G2 of the main unit 24 than to the geometric center P0 of the optical member 22. It is even more preferable that the second oscillation center line CL2 overlaps with the center of gravity G2 of the main unit 24 when viewed in the extension direction of the optical axis LA (Z-axis direction). This allows the second actuator 44 to oscillate the main unit 24 about the second oscillation center line CL2 with a smaller force.

[0076] Furthermore, in this embodiment, as shown in FIG. 4 , the position-detecting magnet 62a of the first position sensor 62 is positioned on the second swing center line CL2. With this arrangement, even when the main unit 24 swings around the second swing center line CL2, the position of the position-detecting magnet 62a does not substantially change. This allows the sensing chip 62b of the first position sensor 62 to detect only the displacement of the position-detecting magnet 62a in the extension direction of the optical axis LA (Z-axis direction) caused by the swing of the subunit 32 around the first swing center line CL1. As a result, the first position sensor 62 can detect the position of the movable part 42b of the first actuator 42 with high accuracy.

[0077] According to the embodiment described above, the level of noise generated when the position of the optical member 22 is changed in the optical path changing device 20 of the projection type image display device 10 can be reduced.

[0078] Specifically, first, the noise level due to the actuators is reduced because the posture of the optical member 22 is changed by the minimum number of actuators (the first and second actuators 42, 44). Furthermore, as described above and as shown in FIG. 4, the noise level due to the actuators is also reduced because the first and second oscillation center lines CL1, CL2 are shifted toward the first and second actuators 42, 44 from the geometric center P0 of the optical member 22.

[0079] Although the present disclosure has been described above with reference to the above-mentioned embodiments, the present disclosure is not limited to these embodiments.

[0080] For example, in the above-described embodiment, the first and second actuators 42, 44 are so-called voice coil type actuators, as shown in Figures 8 and 9. However, the embodiments of the present disclosure are not limited to this. The first and second actuators may be electromagnets.

[0081] In the above-described embodiment of the first and second actuators 42, 44, the coils 46, 54 are supplied with alternating current to generate an alternating magnetic field. However, embodiments of the present disclosure are not limited to this. The coils may be supplied with direct current intermittently to generate a magnetic field intermittently.

[0082] In the above-described embodiment of the first and second actuators 42, 44, the mounting members 52, 56 are elastically deformable leaf springs. However, embodiments of the present disclosure are not limited to this. The mounting members may be, for example, compression coil springs. In other words, in the present disclosure, the mounting members may be made of any material or have any shape as long as they are capable of repeated elastic deformation.

[0083] In the above-described embodiment of the first and second actuators 42, 44, the fixed portions 42a, 44a include coils 46, 54, and the movable portions 42b, 44b include movable magnets 48, 56 and yokes 50, 58. However, this embodiment is not limited to this. The movable portions of the first and second actuators may include coils, and the fixed portions may include magnets and yokes. In this case, a flexible cable must be used to supply current to the moving coils.

[0084] 2, in the optical member 22 of the optical path changing device 20, the incident surface 22a and the exit surface 22b are planar and parallel to each other. However, the embodiment of the present disclosure is not limited to this. The optical member 22 may be, for example, a lens.

[0085] Furthermore, in the above-described embodiment, the first support member 34 and the first actuator 42 are connected via an elastically deformable attachment member 52. Also, the second support member 36 and the second actuator 44 are connected via an elastically deformable attachment member 60. However, the embodiment of the present disclosure is not limited to this. The first support member 34 and the first actuator 42 may be directly connected, or the second support member 36 and the second actuator 44 may be directly connected.

[0086] Furthermore, in the above-described embodiment, the optical member 22 is swung about different first and second swing center lines CL1 and CL2 as the center, as shown in Fig. 2. However, the embodiment of the present disclosure is not limited to this.

[0087] FIG. 12 is a schematic top view of an optical path changing device according to another embodiment.

[0088] 12 , an optical path changing device 120 according to another embodiment includes a support member 134 that supports an optical element 122. The support member 134 is supported by a base member 126 so as to be swingable about a swing center line CL. The support member 134 is also connected to an actuator 142 via an attachment member 152 made of an elastic material. The swing center line CL is shifted toward the actuator 142 with respect to the geometric center P0 of the optical element 22 when viewed in the extension direction of the optical axis LA (Z-axis direction).

[0089] The optical path changing device 120 according to this alternative embodiment can also increase the resolution of the image displayed on the screen.

[0090] That is, in a broad sense, an embodiment of the present disclosure is an optical path changing device comprising: an optical element; a first support member that supports the optical element; a second support member that supports the first support member so that it can swing about a first swing center line that extends in a direction intersecting the propagation direction of light incident on the optical element; a base member that supports the second support member so that it can swing about a second swing center line that extends in a direction intersecting the propagation direction and is different from the first swing center line; a first actuator that is arranged on one side of the first swing center line as viewed in the propagation direction and swings the first support member; and a second actuator that is arranged on one side of the second swing center line as viewed in the propagation direction and swings the second support member, wherein the first swing center line is shifted toward the first actuator with respect to the geometric center of the optical element as viewed in the propagation direction, or the second swing center line is shifted toward the second actuator with respect to the geometric center of the optical element as viewed in the propagation direction.

[0091] Furthermore, another embodiment of the present disclosure is, in a broad sense, an optical path changing device comprising: an optical element; a support member that supports the optical element; a base member that supports the support member so that it can swing about a swing center line that extends in a direction intersecting the propagation direction of light incident on the optical element; and an actuator that is arranged on one side of the swing center line when viewed in the propagation direction and swings the support member, wherein the swing center line is shifted toward the actuator with respect to the geometric center of the optical element when viewed in the propagation direction.

[0092] Furthermore, another embodiment of the present disclosure is, in a broad sense, a projection-type image display device having the above-mentioned optical path changing device, a light source, and an optical modulation module that converts light from the light source into image light and emits the image light toward the optical element of the optical path changing device.

[0093] As described above, the above-described embodiments have been described as examples of the technology of the present disclosure. For this purpose, drawings and detailed descriptions are provided. Therefore, the components described in the drawings and detailed descriptions 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-described technology. Therefore, the fact that these non-essential components are described in the drawings or detailed descriptions should not be interpreted as immediately indicating that these non-essential components are essential.

[0094] 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.

[0095] The present disclosure is applicable to devices that require changing the attitude of an optical member.

Claims

1. an optical member; a first support member that supports the optical member; a second support member that supports the first support member so as to be swingable about a first swing center line that extends in a direction intersecting a propagation direction of light incident on the optical member; a base member extending in a direction intersecting the propagation direction and supporting the second support member so as to be swingable about a second swing center line different from the first swing center line; a first actuator that is disposed on one side of the first swing center line as viewed in the propagation direction and swings the first support member; a second actuator that is disposed on one side of the second swing center line as viewed in the propagation direction and swings the second support member, an optical path changing device, wherein the first oscillation center line is shifted toward the first actuator with respect to the geometric center of the optical element between the geometric center of the optical element and the first actuator when viewed in the propagation direction, or the second oscillation center line is shifted toward the second actuator with respect to the geometric center of the optical element between the geometric center of the optical element and the second actuator when viewed in the propagation direction.

2. 2. The optical path changing device according to claim 1, wherein, when viewed in the propagation direction, the first swing center line is shifted toward the first actuator with respect to the geometric center of the optical element, and the second swing center line is shifted toward the second actuator with respect to the geometric center of the optical element.

3. a subunit including at least the optical member and the first support member, the subunit being configured as a member that swings around the first swing center line, 2. The optical path changing device according to claim 1, wherein the first swing center line is closer to the center of gravity of the subunit than to the geometric center of the optical member.

4. a main unit including at least the subunit and the second support member, the main unit being configured as a member that swings around the second swing center line, 4. The optical path changing device according to claim 3, wherein the second swing center line is closer to the center of gravity of the main unit than to the geometric center of the optical member.

5. the first actuator includes a movable part including a movable magnet and connected to the first support member, and a fixed part including a coil that generates a magnetic field and fixed to the base member, 2. The optical path changing device according to claim 1, wherein the second actuator comprises: a movable part including a movable magnet and connected to the second support member; and a fixed part including a coil that generates a magnetic field and fixed to the base member.

6. a position detection sensor including a position detection magnet attached to the movable portion of the first actuator and a magnetic field detection portion fixed to the base member, 6. The optical path changing device according to claim 5, wherein the position detecting magnet of the position detecting sensor is disposed on the second swing center line.

7. the first actuator includes a first movable part that moves to oscillate the first support member; 2. The optical path changing device according to claim 1, wherein the second actuator comprises a second movable portion that moves to oscillate the second support member.

8. a first connecting member that connects the first support member and the first actuator; a second connecting member that connects the second support member and the second actuator; The optical path changing device according to claim 1 , further comprising:

9. an optical member; a support member for supporting the optical member; a base member supporting the support member so as to be swingable about a swing center line extending in a direction intersecting the propagation direction of light incident on the optical member; an actuator that is arranged on one side of the swing center line as viewed in the propagation direction and swings the support member, an optical path changing device, wherein the swing center line is shifted toward the actuator with respect to the geometric center of the optical member between the geometric center of the optical member and the actuator when viewed in the propagation direction;

10. An optical path changing device according to any one of claims 1 to 9; A light source and a light modulation module that converts light from the light source into image light and emits the image light toward the optical member of the optical path changing device.