JP7838438B2 - Optical path control device, display device, and optical path control method - Google Patents

Description

This invention relates to an optical path control device, a display device, and an optical path control method.

For example, in image display devices using liquid crystal displays, there is a technique to artificially increase resolution by dividing the display period of one frame into multiple subframes, and controlling the optical path control device so that the position of the image projected onto the screen shifts for each subframe's display period, thereby making it appear as if more pixels than the actual number of pixels in the optical modulation element are being projected. For example, such a technique is described in Patent Document 1 below.

Patent No. 3863445

In this method, where the display period of one frame is divided into the display periods of multiple subframes, the projection position may be shifted by oscillating the optical element using an optical path control device. In this case, it is required to appropriately oscillate the oscillating part while appropriately displaying the moving image.

In view of the above problems, the present invention aims to provide an optical path control device, a display device, and an optical path control method that can appropriately display moving images while appropriately oscillating the oscillating part.

An optical path control device according to one aspect of the present invention comprises: a oscillating unit having an optical section into which light is incident; an actuator capable of oscillating the oscillating unit; a drive unit that controls the optical path by applying a drive signal to the actuator to cause the actuator to oscillate the oscillating unit; and a control unit that controls the drive unit. The control unit sets the number of subframes for each frame displaying an image, displaying a portion of the pixels included in the image data of the frame, and sets the oscillation speed of the oscillating unit based on the number of subframes.

An optical path control method according to one aspect of the present invention is an optical path control method that controls an optical path by applying a drive signal to an actuator capable of swinging a swinging part having an optical part into which light is incident,
The method includes the steps of setting the number of subframes for each frame in which an image is displayed, which displays some of the pixels included in the image data of the frame, and setting the oscillation speed of the oscillating part based on the number of subframes.

According to the present invention, it is possible to appropriately display moving images while appropriately oscillating the oscillating part.

Figure 1 is a schematic diagram representing a display device according to Embodiment 1. Figure 2 is a block diagram schematically representing the circuit configuration of the display device. Figure 3 is a plan view showing the optical path control mechanism. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. Figure 5 is a cross-sectional view taken along line V-V in Figure 3. Figure 6 is an explanatory diagram illustrating the two-axis oscillation pattern of the optical unit according to Embodiment 1. Figure 7 is an explanatory diagram illustrating the frame division configuration by the processing unit. Figure 8 is an explanatory diagram illustrating an example of a method for setting the drive signal according to Embodiment 1. Figure 9 is a graph showing an example of the waveform of the drive signal when the motion vector is below a threshold. Figure 10 is a graph showing an example of the oscillation pattern of the oscillating part when the motion vector is below a threshold. Figure 11 is a graph showing an example of the waveform of the drive signal when the motion vector is greater than the threshold. Figure 12 is a graph showing an example of the oscillation pattern of the oscillating part when the motion vector is greater than the threshold. Figure 13 is a schematic diagram showing an example of image display when the motion vector is greater than the threshold. Figure 14 is a schematic diagram showing an example of image display when the motion vector is below a threshold. Figure 15 is a schematic diagram showing an example of image display when the motion vector is below a threshold. Figure 16 is a graph showing another example of the drive signal waveform. Figure 17 is a graph showing another example of the oscillation pattern of the oscillating part. Figure 18 is a schematic diagram showing another example of the order in which pixels are displayed. Figure 19 is a block diagram schematically showing the circuit configuration of the display device according to Embodiment 3.

Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the present invention is not limited to the following embodiments.

[Embodiment 1]
[Outline configuration of the display device]
Figure 1 is a schematic diagram of a display device according to Embodiment 1.

In this embodiment, as shown in Figure 1, the display device 1 comprises an optical path control device 10, an illumination device 100, a video signal processing circuit (processing unit) 160, and a control unit 170 that controls the video signal processing circuit 160. The illumination device 100 is a device that emits light L for the image. The optical path control device 10 is a device that controls the optical path of the light L. The optical path control device 10 shifts the position of the image displayed by the light L by shifting the optical axis of the light L, thereby increasing the resolution of the projected image to a higher resolution than the resolution of the image produced by the illumination device 100 (i.e., the number of pixels of the display element 106, which will be described later).

The illumination device 100 comprises a light source 101, polarizing plates 105R, 105G, 105B, display elements 106R, 106G, 106B, polarizing plates 107R, 107G, 107B, a color-combining prism 108, a projection lens 109, dichroic mirrors 120, 121, reflective mirrors 130, 131, lenses 140, 141, 142, 143, 144, 145, a polarization conversion element 150, and a video signal processing circuit 160. When display elements 106R, 106G, and 106B are not distinguished, they are referred to as display element 106.

Light source 101 is a light source that generates and emits light. Light source 101 emits incident light L0. In the following explanation, we will use a single light source 101 as an example for emitting the incident light L0, but other optical devices for generating the incident light L0 may also be used.

The incident light L0 from the light source 101 enters lens 140. Lenses 140 and 141 are, for example, fly-eye lenses. The incident light L0 has its illumination distribution uniformized by lenses 140 and 141 and enters polarization conversion element 150. Polarization conversion element 150 is an element that aligns the polarization of the incident light L0, and for example, has a polarization beam splitter and a phase difference plate. Polarization conversion element 150 aligns the incident light L0 to p-polarization.

The incident light L0, whose polarization has been aligned by the polarization conversion element 150, is irradiated onto the dichroic mirror 120 via the lens 142. The lens 142 is, for example, a focusing lens.

The dichroic mirror 120 separates the incident light L0 into yellow light LRG and blue light LB containing a component in the blue band. The yellow illumination light LRG separated by the dichroic mirror 120 is reflected by the reflective mirror 130 and incident on the dichroic mirror 121.

The dichroic mirror 121 separates the incident yellow light LRG into red light LR containing a component in the red band and green light LG containing a component in the green band.

The red light LR separated by the dichroic mirror 121 is irradiated onto the polarizer 105R via the lens 143. The green light LG separated by the dichroic mirror 121 is irradiated onto the polarizer 105G via the lens 144. The blue light LB separated by the dichroic mirror 120 is reflected by the reflective mirror 131 and irradiated onto the polarizer 105B via the lens 145.

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

p-polarized red light LR passes through the polarizing plate 105R and illuminates the display element 106R. p-polarized green light LG passes through the polarizing plate 105G and illuminates the display element 106G. p-polarized blue light LB passes through the polarizing plate 105B and illuminates the display element 106B.

Display elements 106R, 106G, and 106B are, for example, reflective liquid crystal display elements. The following explanation uses the case where display elements 106R, 106G, and 106B are reflective liquid crystal display elements as an example, but the explanation is not limited to reflective elements; configurations using transmissive liquid crystal display elements are also possible. Furthermore, various configurations using display elements other than liquid crystal display elements are also possible.

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

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

The s-polarized red light LR generated by display element 106R is reflected by polarizer 105R, passes through polarizer 107R, and irradiates the color-combining prism 108. The s-polarized green light LG generated by display element 106G is reflected by polarizer 105G, passes through polarizer 107G, and irradiates the color-combining prism 108. The s-polarized blue light LB generated by display element 106B is reflected by polarizer 105B, passes through polarizer 107B, and irradiates the color-combining prism 108.

The color-combining prism 108 combines the incident red light (LR), green light (LG), and blue light (LB) to produce light L for image display, which is then projected onto the projection lens 109. Light L is then projected through the projection lens 109 onto a screen or the like (not shown).

While the irradiation device 100 has the configuration described above, its configuration is not limited to that described and may be any configuration.

The optical path control device 10 comprises an optical path control mechanism 12, a control circuit (control unit) 14, and a drive circuit (drive unit) 16. The optical path control mechanism 12 is a mechanism that oscillates when driven by the drive circuit 16. The optical path control mechanism 12 is installed between the color-combining prism 108 and the projection lens 109, in a direction along the optical path of the light L. The optical path control mechanism 12 oscillates as light L from the color-combining prism 108 enters it, shifting the direction of travel (optical path) of the light L and directing it toward the projection lens 109. In this way, the optical path control device 10 controls the optical path of the light L so that its path shifts. Note that the position where the optical path control mechanism 12 is installed is not limited to between the color-combining prism 108 and the projection lens 109, but may be arbitrary.

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

As shown in Figure 2, the video signal processing circuit 160 controls the display elements 106R, 106B, and 106G. The video signal processing circuit 160 receives a video signal including image data for controlling the display elements 106R, 106B, and 106G, and a synchronization signal. The video signal processing circuit 160 controls the display elements 106R, 106B, and 106G based on the image data while synchronizing the timing based on the synchronization signal. The control circuit 14 has a digital circuit 14A and a converter 14B. The digital circuit 14A receives the synchronization signal from the video signal processing circuit 160. The digital circuit 14A generates a digital drive signal for driving the optical path control mechanism 12 while synchronizing the timing based on the synchronization signal. The converter 14B is a DA converter that converts a digital signal to an analog signal. The converter 14B converts the digital drive signal generated by the digital circuit 14A into an analog drive signal. The drive circuit 16 receives the analog drive signal from the converter 14B, amplifies the analog drive signal, and outputs it to the actuator 12B of the optical path control mechanism 12, which will be described later. The actuator 12B is driven according to the drive signal, causing the oscillating section 12A (see Figure 3), which will be described later, to oscillate.

The control unit 170 is a device that controls the drive circuit (drive unit) 16, and in this embodiment, it also controls the video signal processing circuit 160. The control unit 170 is, for example, a computer and has a storage unit and a processing unit (not shown). The storage unit of the control unit 170 is a memory that stores various information such as the calculation contents and programs of the processing unit, and may include at least one of the following: a main memory device such as RAM (Random Access Memory), a ROM (Read Only Memory), and an external memory device such as an HDD (Hard Disk Drive). The program for the processing unit stored in the storage unit may be stored on a recording medium that can be read by the control unit 170. The processing unit of the control unit 170 is a processing device that performs calculations and includes an arithmetic circuit such as a CPU (Central Processing Unit). The processing unit executes the processing performed by the control unit 170 by reading and executing a program (software) from the memory unit. The control unit 170 may execute the processing using a single CPU, or it may have multiple CPUs, with the processing performed by those multiple CPUs. Furthermore, at least a portion of the processing performed by the control unit 170 may be implemented by hardware circuits. The processing performed by the control unit 170 will be described later.

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

As shown in Figures 3 to 5, the optical path control mechanism 12 includes a oscillating section 12A containing an optical element (optical part) 20 into which light L is incident, and an actuator 12B that oscillates the oscillating section 12A.

The actuator 12B oscillates the oscillating part 12A around a first oscillating axis AX and a second oscillating axis BX that are aligned in two directions intersecting (preferably orthogonal) with respect to the direction in which light L is incident on the optical member 20. The first oscillating axis AX and the second oscillating axis BX are preferably orthogonal. Therefore, the optical path control mechanism 12 includes a first oscillating part 21 and a second oscillating part 22 as the oscillating part 12A, a first shaft part 23 and a second shaft part 24 aligned with the first oscillating axis AX and the second oscillating axis BX, a first actuator 25 and a second actuator 26 as the actuator 12B, and a support part 27.

The optical element 20 is a component that transmits incident light L. Light L enters the optical element 20 from one surface, is transmitted through it, and then the light L is emitted from the other surface. The optical element 20 is a glass plate, but its material and shape can be arbitrary.

The first oscillating part 21 comprises an optical member 20 and a first movable part 31. The first movable part 31 is a member that supports the optical member 20. The first movable part 31 is fixed to the optical member 20. Specifically, the first movable part 31 is a frame-shaped member made of plate material with a through hole 31a formed in the center. The optical member 20 is fixed to the first movable part 31 by being fitted into the through hole 31a of the first movable part 31. The optical member 20 is fixed to the first movable part 31 via a fixing member or adhesive, but the method of fixing the optical member 20 to the first movable part 31 is arbitrary.

The second oscillating part 22 is positioned outside the first oscillating part 21. The second oscillating part 22 has a second movable part 32. The second movable part 32 is a member that supports the first movable part 31. The first movable part 31 is supported so as to be able to swing around the first oscillating axis AX relative to the second movable part 32. Specifically, the second movable part 32 is a frame-shaped member of a plate material with a through hole 32a formed in the center. The first movable part 31 is supported so as to be able to swing around the second movable part 32, with a predetermined gap between it and the through hole 32a of the second movable part 32. The first movable part 31 and the second movable part 32 are connected by a pair of first shaft parts 23 that are aligned along the first oscillating axis AX. The first movable part 31 swings around the first oscillating axis AX by elastic deformation such that the pair of second shaft parts 24 twist relative to the second movable part 32.

The support portion 27 is positioned outside the second pivot portion 22. The support portion 27 is a member that supports the second movable portion 32. The second movable portion 32 is supported by the support portion 27 so as to be able to pivot around the second pivot axis BX. Specifically, the support portion 27 is a frame-shaped member made of plate material with a through hole 27a formed in the center. The second movable portion 32 is supported by the support portion 27 so as to be able to pivot, with a predetermined gap between the support portion 27 and the through hole 27a. The second movable portion 32 and the support portion 27 are connected by a pair of second shaft portions 24 that are aligned along the second pivot axis BX. The second movable portion 32 pivots around the second pivot axis BX by the elastic deformation of the pair of second shaft portions 24 so as to twist relative to the support portion 27.

The second movable part 32 (second oscillating part 22) oscillates around the second oscillating axis BX with respect to the support part 27, using a pair of second shaft parts 24 as a fulcrum. The first movable part 31 (first oscillating part 21) oscillates around the first oscillating axis AX with respect to the second movable part 32, using a pair of first shaft parts 23 as a fulcrum. Therefore, the optical member 20 fixed to the second movable part 32 can oscillate around the first oscillating axis AX and the second oscillating axis BX. By oscillating the optical member 20 around the first oscillating axis AX and the second oscillating axis BX, the optical path of the light L passing through the optical member 20 can be shifted by changing the orientation of the optical member 20.

In this embodiment, the first movable part 31, the second movable part 32, the first shaft part 23, and the second shaft part 24 are integrally formed. Therefore, the first movable part 31 swings relative to the second movable part 32 by elastic deformation such that the first shaft part 23 twists in the circumferential direction. However, the first movable part 31, the second movable part 32, and the first shaft part 23 may be formed separately and connected. Furthermore, one end and the other end of the second swing axis BX in the second movable part 32 are fixed to the support part 27, and the second shaft part 24 is formed at each end of the second movable part 32. However, the second shaft part 24 may be provided at each end of the second movable part 32, and each second shaft part 24 may be fixed to the support part 27 directly. Moreover, the second movable part 32, the second shaft part 24, and the support part 27 may be integrally formed.

The first actuator 25 pivots the first movable part 31 (first oscillating part 21) around the first oscillating axis AX, using a pair of first shaft parts 23 as fulcrums relative to the support part 27. The first actuator 25 is positioned on both the radial side (axial direction in the second oscillating axis BX) of the first oscillating axis AX and the other side. The first actuator 25 includes a coil 41, a yoke 42, and a magnet 43.

The coil 41 is attached to the first movable part 31 and fixed to the coil mounting part 31b provided on the first movable part 31. The coil 41 is provided at both ends of the first pivot axis AX in the radial direction (one side and the other side in the axial direction of the second pivot axis BX) of the first movable part 31. The yoke 42 is a member that forms the magnetic path. The yoke 42 is attached to the support part 27 and fixed to the support part 27. The yoke 42 is positioned at both ends of the first movable part 31, corresponding to the coil 41. The magnet 43 is a permanent magnet. The magnet 43 is attached to the yoke 42 and fixed to the yoke 42. The magnet 43 is positioned adjacent to each coil 41.

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

The second actuator 26 pivots the second movable part 32 (second oscillating part 22) around the second oscillating axis BX, using a pair of second shaft parts 24 as fulcrums relative to the support part 27. The second actuator 26 is positioned on both sides of the second oscillating axis BX, in one radial direction (axial direction in the first oscillating axis AX) and the other. The second actuator 26 includes a coil 44, a yoke 45, and a magnet 46.

The coil 44 is attached to the second movable part 32 and fixed to the coil mounting part 32b provided on the second movable part 32. The coil 44 is provided at both ends of the second pivot axis BX in the radial direction (one side and the other side in the axial direction of the first pivot axis AX) of the second movable part 32. The yoke 45 is a member that forms the magnetic path. The yoke 45 is attached to the support part 27 and fixed to the support part 27. The yoke 45 is positioned at both ends of the second movable part 32, corresponding to the coil 44. The magnet 46 is a permanent magnet. The magnet 46 is attached to the yoke 45 and fixed to the yoke 45. The magnet 46 is positioned adjacent to each coil 44.

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

In the optical path control mechanism 12, the first movable part 31 on which the optical element 20 is mounted oscillates, and the second movable part 32 supporting the first movable part 31 also oscillates. Therefore, the optical element 20, the first movable part 31, the second movable part 32, and the coils 41 and 44 can be said to constitute the oscillating part 12A. In other words, the part of the optical path control mechanism 12 that oscillates relative to the support part 27 can be said to refer to the oscillating part 12A. Furthermore, the first shaft part 23 also oscillates together with the second movable part 32 and is therefore included in the oscillating part 12A. Additionally, if fixing members, adhesives, substrates, or lead wires for supplying current to the coils 41 and 44 are provided to fix the optical element 20 to the first movable part 31, these also oscillate relative to the support part 27 and are therefore included in the oscillating part 12A.

In this embodiment, the first movable part 31 is swung by the first actuator 25, and the second movable part 32 is swung by the second actuator 26. In this case, the yokes 42 and 45 constituting each actuator 25 and 26 are fixed to the support part 27. Therefore, when the second movable part 32 is swung by the second actuator 26, a gap is ensured between the first actuator 25 and the second movable part 32 to prevent interference between them. Note that the first actuator 25 may also be provided on the second movable part 32.

The actuators 25 and 26 were of the so-called moving coil type, with coils 41 and 44 positioned in the movable parts 31 and 32. However, they are not limited to this type. For example, they may be of the so-called moving magnet type, with magnets 43 and 46 positioned in the movable parts 31 and 32 and coils 41 and 44 in the support part 27. In this case, since the magnets 43 and 46 oscillate together with the optical member 20, the magnets 43 and 46 are included in the oscillating part 12A instead of the coils 41 and 44.

The optical path control mechanism 12 has the configuration described above, but is not limited to that. It may have any configuration that allows the optical section to shift the optical path of the light L by oscillating due to an actuator to which a drive signal is applied.

[Pixel operation by optical path control mechanism]
The operation of the first oscillating part 21 and the second oscillating part 22 when they are oscillated will be described below. Figure 6 is an explanatory diagram illustrating the two-axis oscillation pattern of the optical unit according to Embodiment 1.

In this embodiment, the optical path control mechanism 12 uses actuator 12B to oscillate the first oscillating part 21 and the second oscillating part 22 in response to an applied drive signal. In this embodiment, the first actuator 25 and the second actuator 26, which constitute actuator 12B, oscillate the first oscillating part 21 and the second oscillating part 22 in response to the drive signal, so as to repeatedly change their orientation from a first angle D1 to a second angle D2 around the first axis AX and the second axis BX, and then from the second angle D2 back to the first angle D1. Through this combination, the optical axis of the light L repeatedly shifts from the first position to the second position, from the second position to the third position, from the third position to the fourth position, and from the fourth position back to the first position. The applied drive signal will be described later.

In other words, the image projected onto the screen by light L when the optical axis is in the first position and the image projected onto the screen when the optical axis is in the second position are shifted by half a pixel, and similarly when the optical axis is in the third and fourth positions, they are each shifted by half a pixel. That is, the image projected onto the screen is always displayed shifted by half a pixel in one of the following directions: up, down, left, right, or diagonally. This increases the apparent number of pixels, allowing for higher resolution images projected onto the screen. Since the optical axis shift is equal to half a pixel of the image, the first angle D1 and the second angle D2 are set to angles that allow the image to be shifted by half a pixel. Note that the image shift amount is not limited to half a pixel; it can be any amount, such as 1/4 or 1/8 of a pixel. The first angle D1 and the second angle D2 can also be set appropriately to match the image shift amount.

The following provides a detailed explanation. Here, the first oscillation axis AX direction and the second oscillation axis BX direction intersect in orthogonal directions and are parallel to the pixel arrangement direction. As shown in Figure 6, the image position P0 is the display position when the current value applied to the first actuator 25 and the second actuator 26 is set to 0, that is, when the displacement angle of the optical member 20 is 0. Operation state A is a state in which the optical member 20 is oscillated by a predetermined angle around the first oscillation axis AX by the first actuator 25, shifting the image position P0 by 1/4 pixel in the direction of the second oscillation axis BX, and the optical member 20 is oscillated by a predetermined angle around the second oscillation axis BX by the second actuator 26, shifting the image position P0 by 1/4 pixel in the direction of the first oscillation axis AX. In other words, operation state A is a state in which the image is displayed at an image position P1 that is shifted to one direction ABXa in the ABX direction, which is the sum of a vector pointing in one direction in the first oscillation axis AX direction and a vector pointing in one direction in the second oscillation axis BX direction.

Similarly, in operation state B, the image is displayed at image position P2, which is shifted to one side ABXb in the ABX direction, obtained by combining the vector pointing in one direction in the first oscillation axis AX direction and the vector pointing in one direction in the second oscillation axis BX direction. Similarly, in operation state C, the image is displayed at image position P3, which is shifted to one side ABXc in the ABX direction, obtained by combining the vector pointing in one direction in the first oscillation axis AX direction and the vector pointing in one direction in the second oscillation axis BX direction. Similarly, in operation state D, the image is displayed at image position P4, which is shifted to one side ABXd in the ABX direction, obtained by combining the vector pointing in one direction in the first oscillation axis AX direction and the vector pointing in one direction in the second oscillation axis BX direction.

<Frame division structure>
Figure 7 is an explanatory diagram illustrating the frame division configuration by the processing unit. In this embodiment, the display period of one frame is divided into the display periods of multiple subframes, and multiple subframes are displayed within the display period of one frame. This effectively increases the resolution of the display device, for example, by displaying image data with an 8K resolution on a display device with a 4K resolution. The division into subframes will be explained below using the case of displaying image data with an 8K resolution on a display device with a 4K resolution as an example.

A subframe is a divided frame that contains some of the pixels of a single frame. In other words, a subframe is a divided frame that displays the image data of some of the pixels of the image data displayed for each pixel during the display period of a single frame. Note that the pixels contained in each subframe within a single frame do not overlap, and the subframes within a single frame contain different pixels from each other; in other words, they display image data of different pixels. In the example in Figure 7, one frame that constitutes image data with a resolution of 8K is composed of multiple combinations of four pixels A, B, C, and D arranged in columns and rows. Each subframe consists of image data to be displayed on a display device with a resolution of 4K. The multiple pixels A, B, C, and D that constitute one frame are divided into four subframes A, B, C, and D. In this case, subframe A is extracted with only the multiple pixels A that constitute one frame. In this case, subframe A displays only one pixel A at the positions of the four pixels A, B, C, and D in the frame. Similarly, subframe B is extracted from only the multiple pixels B that make up one frame. Subframe C is extracted from only the multiple pixels C that make up one frame. Subframe D is extracted from only the multiple pixels D that make up one frame. In this way, the image data of a frame with 8K resolution is displayed as image data of subframes with 4K resolution.

In this embodiment, the control unit 170 sets a subframe for each frame and controls the display element 106 via the video signal processing circuit 160 to display the image data contained in the subframe set for that frame within the display time of that frame. In other words, in this embodiment, the display period of one frame is divided into the display periods of multiple subframes, and multiple subframes are displayed within the display period of one frame.

<Setting the oscillation speed for each frame>
In this embodiment, by oscillating the oscillating unit 12A and displaying multiple subframes within the display period of one frame, image data of subframes having a resolution of, for example, 4K is sequentially displayed at image positions P1 to P4, thereby allowing the user to view an image with a pseudo-8K resolution. In this method of displaying images by dividing them into subframes, it is required to appropriately oscillate the oscillating unit 12A while appropriately displaying the moving image. In contrast, in this embodiment, by setting the number of subframes for each frame and setting the oscillation speed of the oscillating unit 12A based on the number of subframes, it becomes possible to appropriately oscillate the oscillating unit 12A according to the number of subframes while appropriately displaying the moving image.

The method for setting the number of subframes per frame may be arbitrary, but in Embodiment 1, the number of subframes is set based on the motion vector V of the motion region. Similarly, the method for controlling the oscillation speed of the oscillation unit 12A may also be arbitrary, but in Embodiment 1, the oscillation speed of the oscillation unit 12A is set based on the motion vector V of the motion region (in other words, based on the number of subframes set from the motion vector V), and a drive signal capable of achieving the set oscillation speed is set. A detailed explanation follows below.

Figure 8 is an explanatory diagram illustrating an example of a method for setting the drive signal according to Embodiment 1. In Figure 8, as an example of a moving image, frames F1 to F4 show the state in which object 200 (airplane) passes through a space containing object 202 (building), and frames F5 to F6 show a group of images showing the state after object 200 has passed. In this example, objects 200 and 202, such as an airplane and a building, are used as examples of objects that are determined to be in a moving region, but the objects are not limited to these and can be any object. In this embodiment, the objects are those that have been learned in advance and can move or change shape. Furthermore, the data of the objects is stored in the memory unit of the control unit 170.

The control unit 170 acquires image data contained in the frame when setting the drive signal. Specifically, if the frame to be displayed is designated as the second frame, and the frame displayed before the second frame in the time series is designated as the first frame, the control unit 170 acquires the image data contained in the first frame (image data for each pixel displayed during the display period of the first frame) and the image data contained in the second frame (image data for each pixel displayed during the display period of the second frame). Note that the first frame is the frame immediately preceding the second frame in the time series, but is not limited to this; it may be a frame displayed at any time before the second frame (for example, a frame multiple frames before the second frame). Furthermore, multiple frames preceding the second frame may also be designated as the first frame. In the example in Figure 8, if frame F2 is the display target (second frame), the control unit 170 acquires the image data of frame F2 and the image data of frame F1, which is immediately preceding frame F2.

The control unit 170 extracts a target region from the image data in the first frame and the image data in the second frame, and obtains a motion vector between the target region in the first frame and the target region in the second frame. The method for extracting the target region and the method for obtaining the motion vector may be arbitrary, but in this embodiment, the control unit 170 extracts a target region that indicates a common object from the image data in the first frame and the image data in the second frame. The target region refers to the region in the image of the first frame and the image of the second frame in which the same object is captured. That is, the target region in the image of the first frame refers to the region (pixel group) in the image of the first frame in which the object included in the image of the second frame is captured, and the target region in the image of the second frame refers to the region (pixel group) in the image of the second frame in which the object included in the image of the first frame is captured. In the example in Figure 8, objects 200 and 202 are included in both the image of frame F1 and the image of frame F2. Therefore, in the example shown in Figure 8, the control unit 170 extracts the region (pixel group) containing the object 200 from the image data of frame F1 as the target region for object 200 in frame F1, and extracts the region (pixel group) containing the object 200 from the image data of frame F2 as the target region for object 200 in frame F2. Similarly, in the example shown in Figure 8, the control unit 170 extracts the region (pixel group) containing the object 202 from the image data of frame F1 as the target region for object 202 in frame F1, and extracts the region (pixel group) containing the object 202 from the image data of frame F2 as the target region for object 202 in frame F2. The method for extracting the target region from each image data is arbitrary; for example, a known image matching technique for extracting the same object from multiple images may be used. Furthermore, if the entire field of view is moving when comparing the divided frames, the entire field of view is treated as the moving region.

The control unit 170, after extracting the target region, calculates the motion vector V of the target region based on the target region in the first frame and the target region in the second frame. In this embodiment, the target region where the motion vector V is generated is treated as a motion region, which is the region where the motion vector V (amount of movement) is generated. The motion vector V is an index that shows the amount of movement (amount of movement of the motion region) that the motion region moves during the period from the first frame to the second frame. The control unit 170 calculates the motion vector V of the target region (motion region) from the position of the target region in the image of the first frame and the position of the target region in the image of the second frame. That is, for example, the control unit 170 calculates the amount of movement (motion vector) of the target region (motion region) as the difference between the position of the target region in the image of the first frame and the position of the target region in the image of the second frame in a coordinate system based on the image. If there are multiple target regions (motion regions), the control unit 170 calculates the motion vector V for each target region (motion region). In the example shown in Figure 8, the control unit 170 calculates the motion vector V for the motion region of the object 200 based on the position of the object 200 in the first and second frames. Similarly, the control unit 170 calculates the motion vector V for the motion region of the object 202 based on the position of the object 202 in the first and second frames. The control unit 170 may also calculate the direction of movement of the motion region as a motion vector, in addition to the amount of movement of the motion region. That is, the motion vector V may refer only to the amount of movement of the motion region, or it may refer to both the amount of movement of the motion region and its direction of movement. The direction of movement can be calculated from the position of the motion region in the image of the first frame and the position of the motion region in the image of the second frame, in a coordinate system based on the image.

The control unit 170 sets the oscillation speed of the oscillating unit 12A in the second frame, that is, the waveform of the drive signal applied in the second frame in Embodiment 1, based on the calculated motion vector of the motion region. The control unit 170 sets the waveform of the drive signal applied to the actuator 12B in the second frame based on the motion vector (amount of movement) V of the motion region during the period from the first frame to the second frame. In this embodiment, the control unit 170 determines whether the motion vector (amount of movement) V of the motion region is greater than a predetermined threshold. More specifically, the control unit 170 sets the waveform of the drive signal such that the oscillation speed of the oscillating unit 12A due to the application of the drive signal when the motion vector V is greater than the threshold is higher than the oscillation speed of the oscillating unit 12A due to the application of the drive signal when the motion vector V is less than or equal to the threshold. Furthermore, since the oscillation speed changes in proportion to the rate of change of the current value (voltage value) in the waveform of the drive signal, it can be said that the control unit 170 sets the waveform of the drive signal such that the rate of change of the current value (voltage value) of the drive signal when the motion vector V is greater than the threshold is higher than the rate of change of the current value (voltage value) of the drive signal when the motion vector V is less than or equal to the threshold. In other words, the control unit 170 sets the waveform of the drive signal in the second frame to the first waveform, assuming that a moving image will be displayed when the motion vector V is greater than the threshold. Then, the control unit 170 sets the waveform of the drive signal in the second frame to the second waveform, assuming that a still image will be displayed when the motion vector V is less than or equal to the threshold, assuming that the oscillation speed of the oscillation unit 12A is lower than the first waveform (the rate of change of the current value is lower than the first waveform). If there are multiple motion regions, the above determination is made using the motion vector V that has the maximum motion vector (amount of movement) V in each motion region. Furthermore, the threshold here may be set arbitrarily. In the example in Figure 8, when frame F2 is the display target (second frame), the motion vector V of object 200 is greater than the threshold. Similarly, in frames F3 and F4, the motion vector V of object 200 is also greater than the threshold. On the other hand, in frames F5 and F6, object 200 is not visible, and the motion vector V of object 202, which is visible, is below the threshold. Therefore, in the example in Figure 8, the rate of change of the current value in the drive signal in frames F2 to F4 is higher than the rate of change of the current value in the drive signal in frames F5 to F6.

Furthermore, as described above, the control unit 170 can also be said to set the oscillation speed of the oscillation unit 12A based on the number of subframes set based on the motion vector. In this case, the control unit 170 sets the oscillation speed of the oscillation unit 12A such that when the motion vector V is greater than the threshold (i.e., when the number of subframes is greater than the predetermined threshold), the oscillation speed of the oscillation unit 12A is higher than when the motion vector V is less than or equal to the threshold (i.e., when the number of subframes is less than or equal to the predetermined threshold).

The following describes an example of the waveform of the drive signal and the oscillation pattern of the oscillating part 12A caused by that drive signal.

(Waveform of the drive signal when the motion vector is below the threshold)
Figure 9 is a graph showing an example of the waveform of the drive signal when the motion vector is below a threshold, and Figure 10 is a graph showing an example of the oscillation pattern of the oscillating part when the motion vector is below a threshold.

As shown in Figure 9, the drive signal applied from the drive circuit 16 to the first actuator 25 is an electrical signal, and its current value changes over time. That is, the waveform representing the change in the current value of the drive signal over time can be called the waveform of the drive signal. The waveform of the drive signal is shown by a solid line in Figure 9. The drive signal repeats the same waveform every period T. Period T includes a period T1 and a period T2 that follows period T1 and is continuous with period T1. Period T1 corresponds to the period during which the image (an image not shifted by half a pixel) is displayed when the optical axis of the light L is in the first position, and period T2 corresponds to the period during which the image (an image shifted by half a pixel) is displayed when the optical axis of the light L is in the second position.

When the motion vector V is below a threshold, the waveform of the drive signal (second waveform) is set so that each of period T1 and period T2 corresponds to the display period of one frame, in other words, so that the period T corresponds to the display period of two frames. In the example in Figure 9, period T1 corresponds to frame F5 and period T2 corresponds to frame F6. In the second waveform, during the first period TA1 of period T1, the current value changes from the first current value A1 to the second current value A2. Here, the intermediate position 0 between the first current value A1 and the second current value A2 is the position where the current value is 0. In the second waveform, during the first period TA1, the current value changes linearly from the first current value A1 to the second current value A2 as time progresses. That is, in the second waveform, at the start timing of the first period TA1, the current value is the first current value A1, and thereafter the current value changes linearly from the first current value A1 to the end timing of the first period TA1, where the current value is the second current value A2. The first current value A1 is the current value that can hold the first oscillating part 21 at a first angle D1, and is set according to the value of the first angle D1. The second current value A2 is the current value that can hold the first oscillating part 21 at a second angle D2, and is set according to the value of the second angle D2. The first current value A1 and the second current value A2 are current values with opposite signs, but their absolute values may be equal. Figure 9 illustrates a case where the first current value A1 is negative and the second current value A2 is positive.

In the second waveform, the length of the first period TA1 is preferably a value corresponding to the natural frequency of the first oscillating part 21. The first oscillating part 21 refers to the part of the optical path control mechanism 12 that oscillates relative to the support part 27 (in this embodiment, the optical member 20, the first movable part 31, and the coil 41). That is, the length of the first period TA1 is a value corresponding to the natural frequency of the part that oscillates relative to the support part 27. More specifically, the length of the first period TA1 is preferably approximately the same as the natural period of the first oscillating part 21, and more preferably the same as the natural period. Here, the natural period is the reciprocal of the natural frequency. Furthermore, "approximately the same value" means that a value that deviates from the natural period by an error range is also acceptable. For example, if the deviation from the natural period is within 5% of the value of the natural period, it may also be considered "approximately the same value". Hereafter, the description of "approximately the same value" will refer to the same meaning. The natural period (the reciprocal of the natural frequency) is expressed as "1/f" [s], where f [Hz] is the natural frequency.

In the second waveform, the current value is held at the second current value A2 during the second period TB1 within period T1. The second period TB1 is after the first period TA1 and is continuous with the first period TA1. Note that "held at the second current value A2" is not limited to the current value not changing exactly from the second current value A2; it may also include deviations of the current value from the second current value A2 within a predetermined range. This predetermined value can be arbitrarily set, but for example, it may be 10% of the second current value A2.

Thus, in the second waveform, during period T1, the current value gradually changes from the first current value A1 to the second current value A2, and once the current value reaches the second current value A2, it is held at the second current value A2.

In the second waveform, during the third period TA2 of period T2, the current value changes from the second current value A2 to the first current value A1. The third period TA2 is after the second period TB1 and is a continuous period following the second period TB1. Furthermore, in the second waveform, during the third period TA2, the current value changes linearly over time from the second current value A2 to the first current value A1. That is, in the second waveform, at the start of the third period TA2, the current value is the second current value A3, and then changes linearly from the second current value A2, reaching the first current value A1 at the end of the third period TA2.

In the second waveform, the length of the third period TA2 is preferably a value corresponding to the natural frequency of the first oscillation section 21. More specifically, the length of the third period TA2 is preferably approximately the same as the natural period (the reciprocal of the natural frequency) of the first oscillation section 21, and more preferably the same as the natural period. In the third period TA2, the length of the third period TA2 is equal to the length of the first period TA1.

In the second waveform, the current value is held at the first current value A1 during the fourth period TB2 of period T2. The fourth period TB2 is after the third period TA2 and is continuous with the third period TA2. Furthermore, the fourth period TB2 is before the first period TA1 and is continuous with the first period TA1. The fourth period TB2 is equal to the second period TB1. Note that "held at the first current value A1" is not limited to the current value not changing exactly from the first current value A1, but may also include deviations of the current value from the first current value A1 within a predetermined range. This predetermined value can be arbitrarily set, but for example, it may be 10% of the first current value A1.

Thus, in the second waveform, during period T2, the current value gradually changes from the second current value A2 to the first current value A1, and once the current value reaches the first current value A1, it is held at the first current value A1.

As described above, in this embodiment, the second waveform of the drive signal is trapezoidal, and the values during the first period TA1 and the third period TA2, when the current value changes, correspond to the natural frequencies of the oscillating part 12A.

The dashed line in Figure 9 indicates the period during which light L is irradiated. It is preferable that the irradiation device 100 does not irradiate with light L during the first period TA1, but irradiates with light L during the second period TB1. Furthermore, it is preferable that the irradiation device 100 does not irradiate with light L during the third period TA2, but irradiates with light L during the fourth period TB2.

(Oscillation pattern when the motion vector is below the threshold)
As shown in Figure 10, the oscillation pattern of the first oscillation unit 21 refers to the displacement angle of the first oscillation unit 21 (angle around the first oscillation axis AX) over time when a drive signal is applied to the first actuator 25. In Figure 10, the oscillation pattern is shown by a solid line.

In the second waveform, during the first period TA1, the current value of the drive signal changes from the first current value A1 to the second current value A2. As a result, during the first period TA1, the displacement angle of the first oscillating part 21 changes from the first angle D1 to the second angle D2. Here, the intermediate position 0 between the first angle D1 and the second angle D2 is the position where the displacement angle of the first oscillating part 21 is 0.

In the second waveform, during the second period TB1, the drive signal's current value is held at the second current value A2. As a result, the displacement angle of the first oscillating unit 21 is held at the second angle D2 during the second period TB1. Note that "held at the second angle D2" is not limited to the displacement angle not changing exactly from the second angle D2; it may also include the displacement angle deviating from the second angle D2 within a predetermined range. This predetermined value can be set arbitrarily, but for example, it may be 10% of the second angle D2.

In the second waveform, during the third period TA2, the drive signal changes current from the second current value A2 to the first current value A1. As a result, during the third period TA2, the displacement angle of the first oscillating part 21 changes from the second angle D2 to the first angle D1.

In the second waveform, during the fourth period TB2, the drive signal's current value is held at the first current value A1. As a result, the displacement angle of the first oscillating part 21 is held at the first angle D1 during the fourth period TB2. Note that "held at the first angle D1" is not limited to the displacement angle not changing exactly from the first angle D1, but may also include deviations of the displacement angle from the first angle D1 within a predetermined range. This predetermined value can be set arbitrarily, but for example, it may be 10% of the first angle D1.

Furthermore, light L is irradiated during the second period TB1 and the fourth period TB2. Therefore, during the second period TB1, light L irradiates the first oscillating part 21, which is held at the second angle D2, causing the optical path of light L to be in the first position. During the fourth period TB2, light L irradiates the first oscillating part 21, which is held at the first angle D1, causing the optical path of light L to shift to the second position, resulting in a half-pixel shift in the image.

Here, we have described the drive signal applied to the first actuator 25, which is applied from the drive circuit 16 to the actuator 12B. The drive signal applied to the second actuator 26 is similar, so its explanation is omitted.

(Waveform of the drive signal when the motion vector is greater than the threshold)
Figure 11 is a graph showing an example of the waveform of the drive signal when the motion vector is greater than the threshold, and Figure 12 is a graph showing an example of the oscillation pattern of the oscillating part when the motion vector is greater than the threshold.

When the motion vector V exceeds a threshold, the waveform of the drive signal (first waveform) is set so that the period T corresponds to the display period of one frame. In the example in Figure 11, the period T corresponds to frame F2. In the first waveform, the current value is held at zero during the first period TA1. In this embodiment, since the digital circuit 14A etc. includes a digital switching circuit, the supply of current to the actuator 12B can be stopped, and the period during which the current supply is stopped is the period during which the current value is set to zero. In the first waveform, it is preferable that the length of the first period TA1 corresponds to a value corresponding to the natural frequency of the oscillating part 12A. More specifically, it is preferable that the length of the first period TA1 is approximately the same as half the value of the natural period (reciprocal of the natural frequency) of the oscillating part 12A, and more preferably the same as half the value of the natural period (reciprocal of the natural frequency). Note that half the value of the natural period is expressed as "1/(2・f)" [s] when the natural frequency is f [Hz].

In the first waveform, the current value is held at the second current value A2 during the second period TB1. The second period TB1 is after the first period TA1 and is continuous with the first period TA1. That is, at the start of the second period TB1 (the timing of the switch from the first period TA1 to the second period TB1), the current value switches from zero to the second current value A2, and is held at the second current value A2 until the end of the second period TB1.

Thus, in the first waveform, the drive signal during period T1 has its current value held at zero during the first period TA1, switches to the second current value A2 at the start of the second period TB1, and maintains the current value at the second current value A2 during the second period TB1.

In the first waveform, the current value is held at zero during the third period TA2. The third period TA2 is a period that follows the second period TB1 and is continuous with the second period TB1. That is, at the start timing of the third period TA2 (the timing of the switch from the second period TB1 to the third period TA2), the current value switches from the second current value A2 to zero, and the current value is held at zero until the end timing of the third period TA2. In the first waveform, it is preferable that the length of the third period TA2 corresponds to the natural frequency of the oscillating part 12A. More specifically, it is preferable that the length of the third period TA2 is approximately the same as half the natural period (reciprocal of the natural frequency) of the oscillating part 12A, and more preferably the same as half the natural period (reciprocal of the natural frequency). In this embodiment, the length of the third period TA2 is equal to the length of the first period TA1.

In the first waveform, during the fourth period TB2, the current value is held at the first current value A1. The fourth period TB2 is after the third period TA2 and is a continuous period following the third period TA2. That is, at the start of the fourth period TB2 (the timing of the switch from the third period TA2 to the fourth period TB2), the current value switches from zero to the first current value A1, and the current value is held at the first current value A1 until the end of the fourth period TB2.

Thus, in the first waveform, the drive signal during period T2 has its current value held at zero during the third period TA2, switches to the first current value A1 at the start of the fourth period TB2, and is held at the first current value A1 during the fourth period TB2.

Furthermore, in the first waveform, the current value is held at zero during the first period TA1, which follows the fourth period TB2, as described above. That is, at the start of the first period TA1 (the timing of the switch from the fourth period TB2 to the first period TA1), the current value switches from the first current value A1 to zero, and remains at zero until the end of the first period TA1.

The dashed line in Figure 11 indicates the period during which light L is irradiated. It is preferable that the irradiation device 100 does not irradiate with light L during the first period TA1, but irradiates with light L during the second period TB1. Furthermore, it is preferable that the irradiation device 100 does not irradiate with light L during the third period TA2, but irradiates with light L during the fourth period TB2.

(Oscillation pattern when the motion vector is greater than the threshold)
At the start of the first period TA1, in the first waveform, the current value switches from the first current value A1 to zero, and the current value is held at zero until the end of the first period TA1. As a result, the displacement angle of the oscillating part 12A changes from the first angle D1 to the second angle D2 during the first period TA1. More specifically, the oscillating part 12A, which was twisted to the first angle D1 and held at the first current value A1, returns to the neutral position as the current becomes zero, and then, due to the acting inertial force, is twisted to the opposite side, the second angle D2, thus reaching the second angle D2.

At the start of the second period TB1, the current value of the first waveform switches from zero to the second current value A2, and this current value is maintained at the second current value A2 until the end of the second period TB1. As a result, the displacement angle of the oscillating part 12A is maintained at the second angle D2 during the second period TB1. That is, the force attempting to return the oscillating part 12A to its neutral position balances the force due to the second current value A2, thus maintaining it at the second angle D2.

At the start of the third period TA2, the current value in the first waveform switches from the second current value A2 to zero, and remains zero until the end of the third period TA2. As a result, the displacement angle of the oscillating part 12A changes from the second angle D2 to the first angle D1 during the third period TA2.

At the start of the fourth period TB2, the current value in the first waveform switches from zero to the first current value A1, and the current value is maintained at the first current value A1 until the end of the fourth period TB2. As a result, the displacement angle of the oscillating part 12A is maintained at the first angle D1 during the fourth period TB2.

As described above, in this embodiment, when the motion vector V is greater than the threshold, a step-shaped first waveform drive signal is applied, and when the motion vector V is less than or equal to the threshold, a trapezoidal second waveform drive signal is applied. In both the first and second waveforms, the current value changes during periods TA1 and TA2, and the periods TA1 and TA2 in the first waveform are shorter than those in the second waveform. Therefore, it can be seen that the rate of change of the current value, or in other words, the oscillation speed of the oscillating part 12A, is higher in the first waveform shown in this embodiment than in the second waveform.

Furthermore, the waveform of the drive signal set according to the motion vector V is not limited to those shown in the examples in Figures 8 to 12, but may be arbitrary. Also, although the above explanation described two types of drive signal waveforms set according to the motion vector V, this is not limited to two types. For example, three or more types of drive signal waveforms may be set according to the motion vector V. In this case, it is preferable for the control unit 170 to set the drive signal waveform such that the oscillation speed of the oscillation part increases (the rate of change of the current value increases) as the motion vector (amount of movement) V increases (the number of subframes increases).

Furthermore, in this embodiment, the threshold value for the motion vector V is a fixed constant value for each frame and motion region, but it is not limited to this and may be set for each motion region. In this case, for example, the control unit 170 may set the threshold value based on the area of the motion region. More preferably, the control unit 170 may set the threshold value smaller as the area of the motion region increases. This allows for a higher oscillation speed to be set even with a small amount of movement, as the motion region increases.

(Setting subframes according to motion vectors)
In this embodiment, it is preferable to set the waveform of the drive signal for each frame as described above, and also to set the number of subframes for each frame. The method for setting the number of subframes may be arbitrary, but in this embodiment, the number of subframes is set based on the motion vector V. This will be explained in detail below.

When setting the subframe, the control unit 170 extracts the target region (motion region) and calculates the motion vector V of the motion region. The method for extracting the motion region and calculating the motion vector V is the same as when setting the waveform of the drive signal, so the explanation is omitted.

The control unit 170 sets the number of subframes for the second frame based on the calculated motion vector V of the motion region. That is, the control unit 170 sets the number of subframes for the second frame based on the motion vector (amount of movement) V of the motion region during the period from the first frame to the second frame. In this embodiment, the control unit 170 determines whether the motion vector (amount of movement) V of the motion region is greater than a predetermined threshold. More specifically, the control unit 170 sets the number of subframes for the second frame to be greater than the number of subframes for the second frame when the motion vector V is less than or equal to the threshold, if the motion vector V is greater than the threshold. In other words, the control unit 170 sets the number of subframes for the second frame to a first predetermined number, assuming that a moving image will be displayed if the motion vector V is greater than the threshold. Then, the control unit 170 sets the number of subframes for the second frame to a second predetermined number, which is less than the first predetermined number, assuming that a still image will be displayed if the motion vector V is less than or equal to the threshold. Furthermore, if there are multiple motion regions, the above determination is made using the motion vector V that maximizes the motion vector (amount of movement) V within each motion region. The threshold value here can be set arbitrarily. In the example in Figure 8, the number of subframes F2-F4 where the motion vector V is greater than the threshold value is greater than the number of subframes F5-F6 where the motion vector V is less than or equal to the threshold value.

Furthermore, it is preferable that the control unit 170 configures the subframes such that all pixels included in the second frame are included in one of the respective subframes when the motion vector V is greater than the threshold. That is, in the example in Figure 8, four subframes 2A, 2B, 2D, and 2C are configured for frame F2. Of the multiple pixels A, B, C, and D that constitute frame F2, pixel A is included in subframe 2A, pixel B in subframe B, pixel C in subframe 2C, and pixel D in subframe 2D. The same applies to frames F3 and F4, so their explanation is omitted.

Furthermore, when the motion vector V is below a threshold, it is preferable for the control unit 170 to set the subframes such that only some of the pixels included in the second frame are included in one of the respective subframes. In this case, it is also preferable for the control unit 170 to set the subframes such that in the frame following the second frame (the third frame), pixels different from those not included in the subframes of the second frame are included in one of the respective subframes. That is, in the example in Figure 8, in frame F5, two subframes 5A and 5B are set. Of the multiple pixels A, B, C, and D constituting frame F5, pixel A is included in subframe 5A, pixel B is included in subframe 5B, and pixel C is included in subframe 2C. Then, in frame F6, subframes 6D and 6C are set. Of the multiple pixels A, B, C, and D constituting frame F5, pixel D, which was not included in subframes 5A and 5B, is included in subframe 6D, and pixel C is included in subframe 6C. Note that this is not limited to the same line (horizontally arranged); combinations of pixel A and pixel D, and pixel B and pixel C are also acceptable.

In the example shown in Figure 8, the number of subframes (first predetermined number) was 4 when the motion vector V was greater than the threshold, and the number of subframes (second predetermined number) was 2 when the motion vector V was less than or equal to the threshold. However, the first and second predetermined numbers are not limited to these and may be any number. However, it is preferable that the first and second predetermined numbers be set according to the number of pivot axes. Furthermore, in this embodiment, the number of subframes is set to either the first predetermined number or the second predetermined number, but is not limited to these two. For example, the number of subframes to be set may be set to any three or more arbitrary numbers according to the motion vector V. In this case, it is preferable for the control unit 170 to increase the number of subframes as the motion vector (amount of movement) V increases. For example, if the motion vector V is less than or equal to the first threshold, the number of subframes may be 1; if the motion vector V is greater than the first threshold and less than or equal to the second threshold (a value higher than the first threshold), the number of subframes may be 2; and if the motion vector V is greater than the second threshold, the number of subframes may be 4.

Furthermore, in this embodiment, the threshold value for the motion vector V is a fixed constant value for each frame and motion region, but it is not limited to this and may be set for each motion region. In this case, for example, the control unit 170 may set the threshold value based on the area of the motion region. More preferably, the control unit 170 may set the threshold value smaller as the area of the motion region increases. This results in a larger number of subframes even with small amounts of movement, as the motion region increases.

The control unit 170, after setting the number of subframes for the second frame, sets the pixels to be included in the set subframes—in other words, the pixels that will be used to display an image based on the image data during the display period of each subframe—for each subframe.

(Display of images for each subframe)
Once a subframe for the second frame is set, the control unit 170 outputs the information of the set subframe to the video signal processing circuit 160. This causes the control unit 170 to instruct the video signal processing circuit 160 to control the display element 106 so that the image data contained in the subframe set for the second frame is displayed within the time it takes to display the second frame. Furthermore, the control unit 170 instructs the video signal processing circuit 160 to control the display element 106 so that each subframe set for the second frame is displayed sequentially within the time it takes to display the second frame. The display of images for each subframe will be explained in more detail below.

(Image display when the motion vector is greater than the threshold)
Figure 13 is a schematic diagram showing an example of image display when the motion vector is greater than a threshold. In this embodiment, when the motion vector V is greater than a threshold, the subframes are set so that all pixels included in the second frame are included in one of the subframes in the second frame to be displayed. The video signal processing circuit 160 then controls the display elements 106R, 106G, and 106B so that the subframes set for the second frame are displayed sequentially during the time the second frame is displayed. The control circuit 14 then generates a first waveform drive signal based on the synchronization signal input from the video signal processing circuit 160. The drive circuit 16 drives the actuator 12B based on this first waveform drive signal, causing the oscillating part 12A to oscillate. A detailed explanation follows below.

In the examples shown in Figures 8 and 13, the video signal processing circuit 160 controls the display elements 106R, 106G, and 106B so that the four subframes 2A, 2B, 2D, and 2C are displayed sequentially within the time (60 Hz) for displaying the second frame (frame F2 in this case). At this time, the time for displaying each subframe 2A, 2B, 2D, and 2C is 1/4 of the time (240 Hz) for displaying the second frame (60 Hz).

At this time, as shown in Figures 2, 8, and 13, the control circuit 14 generates a first waveform drive signal based on the synchronization signal input from the video signal processing circuit 160, and the drive circuit 16 drives the actuators 25 and 26 based on the drive signal. That is, as shown in Figure 8, when displaying subframe 2A, the drive circuit 16 applies a drive signal (see Figure 11) corresponding to the first waveform in period T1. Then, as shown in Figure 13, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, setting the image position P0 to an A operation state where it is shifted by 1/2 pixel in the direction of the first oscillation axis AX. In other words, the image is displayed at image position P1, which is shifted to one side ABXa in the ABX direction from image position P0.

Subsequently, as shown in Figure 8, when displaying subframe 2B, the drive circuit 16 continues to apply the drive signal (see Figure 11) corresponding to the first waveform during period T1. Then, as shown in Figure 13, the second actuator 26 oscillates the optical element 20 around the second oscillation axis BX, shifting the image position P1 by 1/2 pixel in the direction of the first oscillation axis AX, resulting in operation state B. That is, the image is displayed at image position P2, where image position P0 has shifted to one side ABXb in the ABX direction.

Subsequently, as shown in Figure 8, when displaying subframe 2D, the drive circuit 16 applies a drive signal (see Figure 11) corresponding to the first waveform during period T2. Then, as shown in Figure 13, the first actuator 25 pivots the optical element 20 (see Figure 3) around the first pivot axis AX, shifting the image position P2 by 1/2 pixel in the direction of the second pivot axis BX, resulting in the D operation state. That is, the image is displayed at image position P3, where the image position P0 has shifted to one direction ABXd in the ABX direction.

Subsequently, as shown in Figure 8, when displaying subframe 2C, the drive circuit 16 continues to apply the drive signal (see Figure 11) corresponding to the first waveform during period T2. Then, as shown in Figure 13, the second actuator 26 oscillates the optical element 20 around the second oscillation axis BX, shifting the image position P3 by 1/2 pixel in the direction of the first oscillation axis AX, resulting in the C operation state. That is, the image is displayed at image position P4, where the image position P0 has shifted to one side ABXc in the ABX direction.

(Image display when the motion vector is below the threshold)
Figures 14 and 15 are schematic diagrams showing an example of image display when the motion vector is below a threshold. In this embodiment, when the motion vector V is below a threshold, the subframes are set such that in the second frame to be displayed, only a portion of the pixels included in the second frame are included in one of the subframes, and in the frame following the second frame (third frame), pixels different from those not included in the subframes of the second frame are included in one of the subframes. The video signal processing circuit 160 controls the display elements 106R, 106G, and 106B so that the subframes set for the second frame are displayed sequentially during the time the second frame is displayed, and controls the display elements 106R, 106G, and 106B so that the subframes set for the third frame are displayed sequentially during the time the third frame is displayed. The control circuit 14 generates a second waveform drive signal based on the synchronization signal input from the video signal processing circuit 160. The drive circuit 16 drives the actuator 12B based on this second waveform drive signal, causing the oscillating part 12A to oscillate. The following provides a detailed explanation.

As shown in Figures 8 and 14, the video signal processing circuit 160 controls the display elements 106R, 106G, and 106B so that two of the four divided subframes 5A, 5B, 5C, and 5D (the first subframe group) are displayed sequentially within the time (60 Hz) for displaying the second frame (here, frame F5). At this time, the time for displaying each subframe 5A and 5B is half the time (120 Hz) for displaying frame F5 (60 Hz). Subsequently, as shown in Figures 8 and 15, the video signal processing circuit 160 controls the display elements 106R, 106G, and 106B so that two of the four divided subframes 6A, 6B, 6C, and 6D (the second subframe group) are displayed sequentially within the time (60 Hz) for displaying the third frame (here, frame F6). In this case, the time it takes to display each subframe 6D and 2C is half the time it takes to display the second frame (60 Hz) (120 Hz).

At this time, as shown in Figures 2, 8, and 14, the control circuit 14 generates a second waveform drive signal based on the synchronization signal input from the video signal processing circuit 160, and the drive circuit 16 drives the actuators 25 and 26 based on the drive signal. That is, as shown in Figure 8, when displaying subframe 5A, the drive circuit 16 applies a drive signal (see Figure 9) corresponding to the second waveform during period T1 to the first actuator 25 and the second actuator 26. Then, as shown in Figure 14, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, setting the image position P0 to an A operation state where it is shifted by 1/2 pixel in the direction of the first oscillation axis AX. In other words, the image is displayed at image position P1, which is shifted to one side ABXa in the ABX direction from image position P0.

Subsequently, as shown in Figure 8, when displaying subframe 5B, the drive circuit 16 continues to apply the drive signal (see Figure 9) corresponding to the second waveform during period T1. Then, as shown in Figure 14, the second actuator 26 pivots the optical element 20 around the second pivot axis BX, shifting the image position P1 by 1/2 pixel in the direction of the first pivot axis AX, resulting in the B operation state. That is, the image is displayed at image position P2, where image position P0 has shifted to one side ABXb in the ABX direction.

Subsequently, as shown in Figure 8, when displaying subframe 6D, the drive circuit 16 applies a drive signal (see Figure 9) corresponding to the second waveform during period T2. Then, as shown in Figure 15, the first actuator 25 pivots the optical element 20 (see Figure 3) around the first pivot axis AX, shifting the image position P2 by 1/2 pixel in the direction of the second pivot axis BX, resulting in the D operation state. That is, the image is displayed at image position P3, where image position P0 has shifted by one direction ABXd in the ABX direction.

Subsequently, as shown in Figure 8, when displaying subframe 6C, the drive circuit 16 continues to apply the drive signal (see Figure 9) corresponding to the second waveform during period T2. Then, as shown in Figure 14, the second actuator 26 pivots the optical element 20 around the second pivot axis BX, shifting the image position P3 by 1/2 pixel in the direction of the first pivot axis AX, resulting in the C operation state. That is, the image is displayed at image position P4, where image position P0 has shifted to one side ABXc in the ABX direction.

As explained above, in this embodiment, the waveform of the drive signal in a frame is set based on the motion vector V of the motion region. In this way, since the waveform of the drive signal is set from the motion vector V of the motion region, the waveform of the drive signal can be set according to the motion vector V, that is, based on the determination result of whether or not it is a moving image, so that the oscillating unit 12A can be oscillated appropriately and the moving image can be displayed appropriately. Furthermore, in this embodiment, the waveform of the drive signal is set so that the oscillation speed of the oscillating unit 12A when the motion vector V is greater than the threshold is higher than the oscillation speed when the motion vector V is less than or equal to the threshold. Therefore, for example, in the case of a moving image with a large motion vector V, the oscillation speed can be increased to increase the frame rate and artificially improve the gradation value, so that the moving image can be displayed smoothly. On the other hand, when there are many subframes, the duration of one subframe becomes shorter, so it becomes necessary to increase the oscillation speed of the oscillating unit 12A, and there is a risk that the mechanical life of the optical path control device 10 will be shortened due to fatigue. In contrast, in this embodiment, when the motion vector V is low for a static image, reducing the oscillation speed can suppress fatigue and prevent a shortened lifespan.

(Other examples)
In the above explanation, when the motion vector V is greater than the threshold, the waveform of the drive signal is a step-like shape as shown in Figure 11, and when the motion vector V is less than or equal to the threshold, the waveform of the drive signal is a trapezoidal shape as shown in Figure 9. However, these drive signal waveforms are just examples. Other examples of drive signal waveforms will be explained below.

Figure 16 is a graph showing another example of the drive signal waveform, and Figure 17 is a graph showing another example of the oscillation pattern of the oscillating part. For example, if the motion vector V is greater than the threshold, the drive signal waveform shown in Figure 16 may be set as the first waveform. As shown in Figure 16, in the drive signal waveform of this example, in the first period TA1, the current value is held at the second current value A2, and then held at the first current value A1. That is, in period TA1a of the first period TA1, the current value is held at the second current value A2, and in period TA1b of the first period TA1, the current value is held at the first current value A1. Period TA1b is a period that is after period TA1a and continuous with period TA1a. In other words, at the start of period TA1b (the timing of the switch from period TA1a to period TA1b), the current value switches from the second current value A2 to the first current value A1, and the current value is maintained at the first current value A1 until the end of period TA1b.

The length of the first period TA1 is preferably a value corresponding to the natural frequency of the oscillating part 12A. The length of the first period TA1 is preferably approximately the same as one-third of the natural period (the reciprocal of the natural frequency) of the oscillating part 12A, and more preferably the same as one-third of the natural period. Note that one-third of the natural period (the reciprocal of the natural frequency) is expressed as "1/(3・f)" [s], where the natural frequency is f [Hz].

Furthermore, within the first period TA1, the lengths of period TA1a and period TA1b correspond to the natural frequencies of the oscillating part 12A. It is preferable that the lengths of period TA1a and period TA1b are the same. More specifically, it is preferable that the lengths of period TA1a and period TA1b are approximately equal to one-sixth of the natural period (the reciprocal of the natural frequency) of the oscillating part 12A, and more preferably they are exactly the same as one-sixth of the natural period. Note that one-sixth of the reciprocal of the natural frequency is expressed as "1/(6・f)" [s], where the natural frequency is f [Hz].

In this example's drive signal waveform, the current value is held at the second current value A2 during the second period TB1. The second period TB1 is after the first period TA1 (period TA1b) and is a continuous period following the first period TA1 (period TA1b). That is, at the start of the second period TB1 (the timing of the switch from period TA1b to the second period TB1), the current value switches from the first current value A1 to the second current value A2, and is held at the second current value A2 until the end of the second period TB1.

Thus, in this example, the drive signal during period T1 has its current value held at the second current value A2 during period TA1a, switched to and held at the first current value A1 during period TA1b, and switched to and held at the second current value A2 during the second period TB1.

In this example's drive signal waveform, during the third period TA2, the current value is held at the first current value A1, and then held at the second current value A2. That is, at the start of period TA2a within the third period TA2 (the timing of the switch from the second period TB1 to period TA2a), the current value switches from the second current value A2 to the first current value A1, and is held at the first current value A1 until the end of period TA2a. Period TA2b is after period TA2a and is continuous with period TA2a. That is, at the start of period TA2b (the timing of the switch from period TA2a to period TA2b), the current value switches from the first current value A1 to the second current value A2, and is held at the second current value A2 until the end of period TA2b.

The length of the third period TA2 is preferably a value corresponding to the natural frequency of the oscillating part 12A. Preferably, the length of the third period TA2 is approximately the same as one-third of the natural period (the reciprocal of the natural frequency) of the oscillating part 12A, and more preferably, it is the same as one-third of the natural period. In this embodiment, the length of the third period TA2 is equal to the length of the first period TA1.

Furthermore, within the third period TA2, the lengths of period TA2a and period TA2b correspond to values that match the natural frequencies of the oscillating section 12A. It is preferable that the lengths of period TA2a and period TA2b are the same. More specifically, it is preferable that the lengths of period TA2a and period TA2b are approximately equal to one-sixth of the reciprocal of the natural frequency of the oscillating section 12A, and more preferably equal to one-sixth of the natural period. In this embodiment, the length of period TA2a is equal to the length of period TA1a, and the length of period TA2b is equal to the length of period TA1b.

In this example's drive signal waveform, the current value is held at the first current value A1 during the fourth period TB2. The fourth period TB2 is after the third period TA2 (period TA2b) and is a continuous period following the third period TA2 (period TA2b). That is, at the start of the fourth period TB2 (the timing of the switch from period TA2b to the fourth period TB2), the current value switches from the second current value A2 to the first current value A1, and the current value is held at the first current value A1 until the end of the fourth period TB2.

Thus, in this example, the drive signal during period T2 has its current value held at the first current value A1 during period TA2a, switched to and held at the second current value A2 during period TA2b, and switched back to and held at the first current value A1 during the fourth period TB2.

Furthermore, in period TA1a, which follows the fourth period TB2, the current value is held at the second current value A2, as described above. That is, at the start of period TA1a (the timing of the switch from the fourth period TB2 to period TA1a), the current value switches from the first current value A1 to the second current value A2, and is held at the second current value A2 until the end of period TA1a.

In this example, a drive signal with the waveform described above is applied. As shown in Figure 17, the displacement angle of the oscillating part 12A changes from the first angle D1 to the second angle D2 during the first period TA1 (periods TA1a and TA1b). More specifically, against the force trying to twist back at the first angle D1, a further force is applied in the direction of the return using the second current value A2, accelerating the oscillating part 12A towards the second angle D2. Since inertia would cause it to twist further beyond the second angle D2, in this embodiment, the first current value A1 is then applied to act as a brake. Therefore, the oscillating part 12A can be made to oscillate at high speed.

At the start of the second period TB1, the drive signal switches the current value from the first current value A1 to the second current value A2, and the current value is held at the second current value A2 until the end of the second period TB1. As a result, the displacement angle of the oscillating part 12A is maintained at the second angle D2 during the second period TB1.

The drive signal switches the current value from the second current value A2 to the first current value A1 at the start of period TA2a, and the current value is held at the first current value A1 until the end of period TA2a. At the start of period TA2b, the current value switches from the first current value A1 to the second current value A2, and the current value is held at the second current value A2 until the end of period TA2b. As a result, the displacement angle of the oscillating part 12A changes from the second angle D2 to the first angle D1 during the third period TA2 (periods TA2a and TA2b).

At the start of the fourth period TB2, the drive signal switches the current value from the second current value A2 to the first current value A1, and the current value is held at the first current value A1 until the end of the fourth period TB2. As a result, the displacement angle of the oscillating part 12A is maintained at the first angle D1 during the fourth period TB2.

Three examples of drive signal waveforms have been described so far, but these waveforms may be set according to the motion vector V as follows. That is, for example, as described in the above embodiment, when the motion vector V is below the threshold, a trapezoidal shape as shown in Figure 9 may be used, and when the motion vector V is greater than the threshold, a stepped shape as shown in Figure 11 may be used. Also, for example, as described in the other example above, when the motion vector V is below the threshold, a trapezoidal shape as shown in Figure 9 may be used, and when the motion vector V is greater than the threshold, a shape as shown in Figure 16 may be used. Also, for example, when the motion vector V is below the threshold, a stepped shape as shown in Figure 11 may be used, and when the motion vector V is greater than the threshold, a shape as shown in Figure 16 may be used. Furthermore, for example, when the motion vector V is below the first threshold, a trapezoidal shape as shown in Figure 9 may be used, when the motion vector V is greater than the first threshold and below a second threshold higher than the first threshold, a stepped shape as shown in Figure 11 may be used, and when the motion vector V is greater than the second threshold, a shape as shown in Figure 16 may be used.

Furthermore, while the above explanation assumed that the subframes were set to display pixels A, B, D, and C in that order, the order in which pixels are displayed is not limited to this and can be arbitrary. Figure 18 is a schematic diagram showing another example of the order in which pixels are displayed. For example, as shown in Figure 18, the subframes may be set to display pixels A, D, B, and C in that order.

[Embodiment 2]
In Embodiment 2, the method for extracting the motion region and the method for obtaining the motion vector V differ from those in Embodiment 1. In Embodiment 2, the same configurations and processes as in Embodiment 1 will not be described.

In Embodiment 2, the control unit 170 acquires image data from the first frame and image data from the second frame. The control unit 170 then calculates a motion vector V and a motion region based on the image data from the first frame and the second frame (by comparing the image data from the first frame and the second frame). Specifically, the control unit 170 extracts the moving region from the image data, i.e., the region where the motion vector V is generated, as the motion region, based on the image data from the first frame and the second frame. That is, in Embodiment 2, the control unit 170 calculates the motion vector V based on the image data from the first frame and the second frame, and extracts the region where the motion vector V is greater than a predetermined value (for example, greater than zero) as the motion region. Note that the setting of subframes is not limited to using a motion vector V that includes both the amount of movement and the direction of movement; only the magnitude of the movement (amount of movement) between the first frame and the second frame may be used to set the number of subframes. The method for calculating the motion vector V in Embodiment 2 may be arbitrary, and known methods may be used. For example, a block matching method may be used to calculate the motion vector V. In the block matching method, for instance, the image is divided into multiple blocks, and a correlation calculation is performed between the first and second frames for each block. The motion vector V is then calculated from the correlation value obtained in this calculation. Blocks where the motion vector V is greater than a predetermined value may then be calculated as the motion region. Furthermore, the motion region, motion vector V, and motion amount in Embodiment 2 may be acquired from an external device via a communication unit (not shown). Also, the motion region is not limited to the region where the motion vector V is generated; it may also be the region where the motion amount is generated.

[Embodiment 3]
Embodiment 3 differs from the above embodiment in that the oscillation speed of the oscillation unit is set based on the number of subframes. In Embodiment 3, the same configurations and processes as in the above embodiment will not be described.

Figure 19 is a schematic block diagram showing the circuit configuration of the display device according to Embodiment 3. The control unit 170 includes a subframe setting unit 172.

The subframe setting unit 172 sets the number of subframes for each frame. The subframe setting unit 172 may set the number of subframes using any method. For example, the subframe setting unit 172 may set the number of subframes based on the calculated motion region and motion vector V, as in Embodiment 1 or Embodiment 2. Alternatively, the subframe setting unit 172 may acquire information about the category (type) of the program (content) displayed by the display device and set the number of subframes according to the program category. The subframe setting unit 172 may acquire the program category information using any method; for example, it may read the program category stored in the memory unit of the control unit 170, or it may acquire the program category by communicating with a server where the program category is stored via the communication unit of the control unit 170, or it may classify the category from the image data using a known method.

The subframe setting unit 172 may set the number of subframes according to any criteria depending on the program category. For example, when playing programs in categories where there is a lot of movement or where high resolution is expected, such as sports or movies, the number of subframes may be set to be high. Conversely, for programs in categories where there is little movement or where low resolution is expected, such as information programs, the number of subframes may be set to be low in order to prioritize the lifespan of the device.

The control unit 170 sets the oscillation speed of the oscillation unit 12A based on the number of subframes. For example, the control unit 170 sets the oscillation speed of the oscillation unit 12A such that when the number of subframes exceeds a predetermined threshold, the oscillation speed of the oscillation unit 12A is higher than when the number of subframes is less than or equal to the predetermined threshold. Then, the control unit 170 selects a drive signal waveform suitable for the oscillation speed—that is, a drive signal waveform that can achieve the set oscillation speed—and applies a drive signal with that waveform.

(effect)
As described above, the optical path control device 10 according to this embodiment includes a oscillating unit 12A having an optical element (optical part) 20 into which light is incident, an actuator 12B capable of oscillating the oscillating unit 12A, a drive circuit (drive unit) 16 that controls the optical path by causing the actuator 12B to oscillate the oscillating unit 12A by applying a drive signal to the actuator 12B, and a control unit 170 that controls the drive circuit 16. The control unit 170 sets the number of subframes that display some of the pixels included in the image data of the frame for each frame in which an image is displayed, and sets the oscillation speed of the oscillating unit 12A based on the number of subframes. As a result, the oscillating unit 12A can be oscillated appropriately while the moving image can be displayed appropriately.

According to the optical path control device 10 of this embodiment, the control unit 170 sets the oscillation speed of the oscillation unit 12A driven by the drive signal to be higher when the number of subframes exceeds a predetermined threshold than when the number of subframes is below the predetermined threshold. As a result, in the case of a moving image with a large number of subframes, the oscillation speed is increased to increase the frame rate while simultaneously artificially improving the gradation value, allowing for smoother display of the moving image. Furthermore, in the case of an image with a small number of subframes, the oscillation speed can be reduced to improve the device's lifespan.

Furthermore, the control unit 170 extracts motion regions representing common objects from the image data in the first frame and the image data in the second frame (which follows the first frame). It then obtains motion vectors between the motion regions in the first and second frames, and based on these motion vectors, sets the number of subframes in the second frame and the oscillation speed of the oscillation unit 12A. By setting the oscillation speed based on the motion vectors, the oscillation unit 12A can be appropriately oscillated while the moving image is displayed appropriately.

Furthermore, the display device 1 according to this embodiment includes an optical path control device 10 and a video signal processing circuit (processing unit) 160 that controls the display element 106 based on image data. The control unit 170 causes the video signal processing circuit 160 to control the display element 106 so that a subframe set for that frame is displayed within the time it takes to display the frame. As a result, in the case of a still image with a low motion vector V, reducing the oscillation speed can suppress fatigue and prevent a shortened lifespan.

Furthermore, the optical path control method according to this embodiment is an optical path control method that controls the optical path by applying a drive signal to an actuator 12B capable of oscillating a oscillating unit 12A having an optical element (optical part) 20 into which light L is incident. The method includes the steps of: setting the number of subframes that display a portion of the pixels included in the image data of a frame for each frame in which an image is displayed; and setting the oscillation speed of the oscillating unit 12A based on the number of subframes. As a result, the oscillating unit 12A can be appropriately oscillated while the moving image is displayed appropriately.

In the embodiment described above, the optical member 20 is supported so as to be pivotable by a first shaft portion 23 along the first pivot axis AX and by a second shaft portion 24 along the second pivot axis BX. However, the configuration is not limited to this.

Although the display device 1 according to the present invention has been described so far, it may be implemented in various other forms besides those described above.

The components of the illustrated display device 1 are functionally conceptual and do not necessarily have to be physically configured as shown. In other words, the specific form of each device is not limited to those shown; depending on the processing load and usage conditions of each device, all or part of them may be functionally or physically distributed or integrated in any unit.

The configuration of the display device 1 is realized, for example, as software, such as a program loaded into memory. In the above embodiment, these were described as functional blocks realized through the cooperation of hardware and software. That is, these functional blocks can be realized in various forms using hardware alone, software alone, or a combination thereof.

The above-described components include those that are readily conceivable to those skilled in the art, and those that are substantially identical. Furthermore, the above-described components can be combined as appropriate. In addition, various omissions, substitutions, or modifications of the components are possible without departing from the spirit of the present invention.

1 Display device 10 Optical path control device 12 Optical path control mechanism 12A Oscillating part 12B Actuator 14 Control circuit 16 Drive circuit (drive part)
20. Optical components (optical parts)
21 First oscillating part 22 Second oscillating part 23 First shaft part 24 Second shaft part 25 First actuator 26 Second actuator 27 Support part 31 First movable part 32 Second movable part 100 Irradiation device 106 Display element 160 Video signal processing circuit (processing unit)
170 Control Unit A1 First current value A2 Second current value AX First oscillation axis BX Second oscillation axis D1 First angle D2 Second angle L Light TA1, TA2 First period TB1, TB2 Second period V Motion vector

Claims (4)

A rocking part having an optical section into which light is incident,
The aforementioned swinging part is provided with a swingable actuator,
A drive unit controls the optical path by applying a drive signal to the actuator, thereby causing the actuator to oscillate the oscillating part,
A control unit that controls the drive unit,
Equipped with,
The control unit,
The amount of motion is obtained from the image data in the first frame and the image data in the second frame which is after the first frame.
If the amount of movement is greater than a predetermined threshold, the number of subframes of the second frame is set to a first predetermined number, and if the amount of movement is less than or equal to the predetermined threshold, it is set to a second predetermined number which is less than the first predetermined number.
Based on the number of subframes, the oscillation speed of the oscillating part is set.
Optical path control device. The optical path control device according to claim 1, wherein the control unit makes the oscillation speed of the oscillation unit higher when the subframe is greater than a predetermined threshold than the oscillation speed of the oscillation unit when the subframe is less than or equal to the threshold. The optical path control device according to claim 1 or claim 2,
The system includes a processing unit that controls a display element based on the image data,
The control unit,
The processing unit is instructed to control the display element so that the subframe set for the frame is displayed within the time frame the frame is displayed.
Display device. An optical path control method that controls the optical path by applying a drive signal to an actuator capable of swinging a swinging part having an optical part into which light is incident,
A step of obtaining the amount of motion from the image data in the first frame and the image data in the second frame which is later than the first frame,
If the amount of movement is greater than a predetermined threshold, the number of subframes of the second frame is set to a first predetermined number, and if the amount of movement is less than or equal to the predetermined threshold, it is set to a second predetermined number which is less than the first predetermined number.
The steps include setting the oscillation speed of the oscillating part based on the number of subframes,
including,
Optical path control method.