Display device and display method

Abstract

To allow a video to be smoothly displayed and display an appropriate gray scale at the same time.SOLUTION: The display device includes a processing unit for controlling a display element on the basis of image data and a control unit for controlling the processing unit. The control unit acquires a motion amount from image data in a first frame and image data in a second frame after the first frame, sets the number of sub frames which display a part of the pixels in image data of the second frame for the second frame on the basis of the motion amount, and causes the processing unit to control the display element so that the sub frame set for the second frame is displayed within the time of display of the second frame.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a display device and a display method.

Background Art

[0002] For example, as an image display device using a liquid crystal display element, in order to pseudo-increase the resolution, the display period of one frame is divided into the display periods of a plurality of sub-frames, and an optical path control device is controlled so that the position where it is projected onto the screen shifts for each display period of each sub-frame, thereby making it appear as if more pixels than the number of pixels of the light modulation element are projected. For example, such a technique is described in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a method of dividing and displaying the display period of one frame into the display periods of a plurality of sub-frames in this way, it is also required to appropriately display a moving image while displaying appropriate gradations.

[0005] In view of the above problems, an object of the present invention is to provide a display device and a display method capable of smoothly displaying a moving image while displaying appropriate gradations.

Means for Solving the Problems

[0006] A display device according to one aspect of the present invention comprises a processing unit that controls a display element based on image data, and a control unit that controls the processing unit, wherein the control unit obtains motion data from the image data in a first frame and the image data in a second frame that follows the first frame, sets the number of subframes for the second frame to display some of the pixels included in the image data of the second frame based on the motion data, and causes the processing unit to control the display element so that the subframes set for the second frame are displayed within the time it takes to display the second frame.

[0007] A display method according to one aspect of the present invention includes the steps of: obtaining a motion amount from image data in a first frame and image data in a second frame that follows the first frame; setting the number of subframes for the second frame to display some of the pixels included in the image data of the second frame based on the motion amount; and controlling a display element so that the subframes set for the second frame are displayed within the time it takes to display the second frame. [Effects of the Invention]

[0008] According to the present invention, it is possible to display moving images appropriately while displaying appropriate gradations. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram representing the display device according to Embodiment 1. [Figure 2] Figure 2 is a block diagram schematically representing the circuit configuration of the display device. [Figure 3] Figure 3 is a plan view showing the optical path control mechanism. [Figure 4] Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3. [Figure 5] Figure 5 is a cross-sectional view of the VV section of Figure 3. [Figure 6] Figure 6 is a graph illustrating the waveform of the drive signal of the drive unit. [Figure 7] Figure 7 is a graph illustrating the uniaxial oscillation pattern of the optical unit. [Figure 8] Figure 8 is an explanatory diagram illustrating the two-axis oscillation pattern of the optical unit. [Figure 9] Figure 9 is a graph illustrating the two-axis oscillation pattern of the optical unit. [Figure 10] Figure 10 is an explanatory diagram illustrating the frame division configuration by the processing unit. [Figure 11] Figure 11 is an explanatory diagram illustrating an example of a method for displaying subframes according to Embodiment 1. [Figure 12] Figure 12 is a schematic diagram showing an example of image display when the motion vector is greater than the threshold. [Figure 13] Figure 13 is a schematic diagram showing an example of image display when the motion vector is below a threshold. [Figure 14] Figure 14 is a schematic diagram showing an example of image display when the motion vector is below a threshold. [Figure 15] Figure 15 is a schematic diagram showing another example of the order in which pixels are displayed. [Modes for carrying out the invention]

[0010] 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.

[0011] [Embodiment 1] [Outline configuration of the display device] Figure 1 is a schematic diagram of a display device according to Embodiment 1.

[0012] In this embodiment, as shown in FIG. 1, the display device 1 includes an optical path control device 10, an irradiation device 100, a video signal processing circuit (processing unit) 160, and a control unit 170 that controls the video signal processing circuit 160. The irradiation device 100 is a device that irradiates light L for an image. The optical path control device 10 is a device that controls the optical path of the light L. The optical path control device 10 shifts the position of the image displayed by the light L by shifting the optical axis of the light L, and makes the resolution of the projected image higher than the resolution of the image (that is, the number of pixels of the display element 106 described later) by the irradiation device 100.

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

[0014] The light source 101 is a light source that generates and irradiates light. The light source 101 irradiates incident light L0. In the following description, as an example, one light source 101 is used as the light source that irradiates the incident light L0, but other optical devices for generating the incident light L0 may be provided.

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

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

[0017] The dichroic mirror 120 separates the incident light L0 into yellow light LRG and blue light LB, which contains components 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.

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

[0019] 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.

[0020] Polarizers 105R, 105G, and 105B have the property of reflecting either s-polarized or p-polarized light and transmitting the other. For example, polarizers 105R, 105G, and 105B reflect s-polarized light and transmit p-polarized light. Polarizers 105R, 105G, and 105B are also called reflective polarizers.

[0021] p-polarized red light LR passes through polarizer 105R and irradiates display element 106R. p-polarized green light LG passes through polarizer 105G and irradiates display element 106G. p-polarized blue light LB passes through polarizer 105B and irradiates display element 106B.

[0022] Display elements 106R, 106G, and 106B are, for example, reflective liquid crystal display elements. In the following explanation, the case in which display elements 106R, 106G, and 106B are reflective liquid crystal display elements will be used as an example, but the explanation is not limited to reflective elements, and a configuration using transmissive liquid crystal display elements is also possible. Furthermore, various configurations using display elements other than liquid crystal display elements are also possible.

[0023] 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.

[0024] Polarizers 107R, 107G, and 107B have the property of transmitting either s-polarized or p-polarized light, and reflecting or absorbing the other. For example, polarizers 107R, 107G, and 107B transmit s-polarized light and absorb unwanted p-polarized light.

[0025] The s-polarized red light LR generated by the display element 106R is reflected by the polarizer 105R, passes through the polarizer 107R, and irradiates the color-combining prism 108. The s-polarized green light LG generated by the display element 106G is reflected by the polarizer 105G, passes through the polarizer 107G, and irradiates the color-combining prism 108. The s-polarized blue light LB generated by the display element 106B is reflected by the polarizer 105B, passes through the polarizer 107B, and irradiates the color-combining prism 108.

[0026] 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 projected through the projection lens 109 onto a screen or the like (not shown).

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

[0028] 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, thereby shifting the direction of propagation (optical path) of the light L and causing it to exit towards the projection lens 109. In this way, the optical path control device 10 controls the optical path of the light L so that the optical path of the light L shifts. Note that the position where the optical path control mechanism 12 is installed is not limited to between the color-combining prism 108 and the projection lens 109, but may be any position.

[0029] [Display device function configuration] Figure 2 is a block diagram schematically showing the circuit configuration of the display device.

[0030] 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 that includes 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 and causes the oscillating part 12A (see Figure 3), which will be described later, to oscillate.

[0031] The control unit 170 is a device that controls the video signal processing circuit 160. The control unit 170 is, for example, a computer and has a memory unit and a processing unit (not shown). The memory 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: RAM (Random Access Memory), main memory such as ROM (Read Only Memory), and external memory such as HDD (Hard Disk Drive). The program for the processing unit stored in the memory unit may be stored on a recording medium that the control unit 170 can read. The processing unit of the control unit 170 is a processing unit that performs calculations and includes calculation circuits 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 with one CPU, or it may have multiple CPUs and execute the processing with those multiple CPUs. In addition, at least a part of the processing performed by the control unit 170 may be implemented with hardware circuits. The processing performed by the control unit 170 will be described later.

[0032] [Optical path control mechanism] Figure 3 is a plan view showing the optical path control mechanism, Figure 4 is a cross-sectional view of Figure 3 at line IV-IV, and Figure 5 is a cross-sectional view of Figure 3 at line VV.

[0033] As shown in Figures 3 to 5, the optical path control mechanism 12 includes a oscillating part 12A that includes an optical element (optical part) 20 into which light L is incident, and an actuator 12B that oscillates the oscillating part 12A.

[0034] 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. Preferably, the first oscillating axis AX and the second oscillating axis BX are 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.

[0035] The optical component 20 is a component that transmits incident light L. Light L enters the optical component 20 from one surface, is transmitted through it, and then exits from the other surface. The optical component 20 is a glass plate, but the material and shape may be arbitrary.

[0036] The first oscillating part 21 has an optical member 20 and a first movable part 31. The first movable part 31 is a member that supports the optical member 20. The first movable part 31 is fixed to the optical member 20. Specifically, the first movable part 31 is a member that has the shape of a frame 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 for fixing to the first movable part 31, but the method of fixing the optical member 20 to the first movable part 31 may be arbitrary.

[0037] 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 member that has the shape of a frame made of 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 a pair of second shaft parts 24 twist relative to the second movable part 32.

[0038] 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 member that has the shape of a frame 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 of the support portion 27. 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 elastic deformation such that the pair of second shaft portions 24 twist relative to the support portion 27.

[0039] 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.

[0040] 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. In addition, one end and the other end of the second swing shaft BX in the second movable part 32 are fixed to the support part 27 so as to be connected, 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 so as to be directly connected to the support part 27. Furthermore, the second movable part 32, the second shaft part 24, and the support part 27 may be integrally formed.

[0041] The first actuator 25 pivots the first movable part 31 (first oscillating part 21) around the first oscillating axis AX, with a pair of first shaft parts 23 acting as fulcrums relative to the support part 27. The first actuator 25 is positioned on both the radial side (axial side 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.

[0042] 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 of the first pivot axis AX of the first movable part 31 (one side and the other side in the axial direction of the second pivot axis BX). The yoke 42 is a member that forms a magnetic path. The yoke 42 is attached to the support part 27 and fixed to the support part 27. The yoke 42 is 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.

[0043] A drive signal from the drive circuit 16 (see Figure 2) is input to the coil 41. 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 the air gap. When a 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.

[0044] The second actuator 26 pivots the second movable part 32 (second oscillating part 22) about the second oscillating axis BX, with a pair of second shaft parts 24 acting 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.

[0045] 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 a 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.

[0046] A drive signal from the drive circuit 16 (see Figure 2) is input to the coil 44. 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 placed within this air gap. When a 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, generating a force in the coil 44. This force causes the second movable part 32 (second oscillating part 22), which is 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.

[0047] In the optical path control mechanism 12, the first movable part 31 on which the optical element 20 is provided oscillates, and the second movable part 32 on which the first movable part 31 is supported 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 be the oscillating part 12A. The first shaft part 23 also oscillates together with the second movable part 32 and is therefore included in the oscillating part 12A. Furthermore, if there are fixing members or adhesives for fixing the optical element 20 to the first movable part 31, or bases or lead wires for supplying current to the coils 41 and 44, these also oscillate relative to the support part 27 and are therefore included in the oscillating part 12A.

[0048] 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 that constitute 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 so that they do not interfere with each other. The first actuator 25 may also be provided on the second movable part 32.

[0049] Although actuators 25 and 26 were of the so-called moving coil type, with coils 41 and 44 positioned on the movable parts 31 and 32, they are not limited to this. For example, they may be of the so-called moving magnet type, with magnets 43 and 46 positioned on the movable parts 31 and 32 and coils 41 and 44 positioned on the support part 27. In this case, since magnets 43 and 46 oscillate together with the optical member 20, magnets 43 and 46 are included in the oscillating part 12A instead of coils 41 and 44.

[0050] 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 with an actuator to which a drive signal is applied.

[0051] [Drive signal] Here, we will explain the drive signal applied from the drive circuit 16 to the actuator 12B. Figure 6 is a graph illustrating the waveform of the drive signal of the drive unit.

[0052] As shown in Figure 6, 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. Hereinafter, the waveform representing the change in the current value of the drive signal over time will be referred to as the drive signal waveform. The drive signal waveform is shown by a solid line in Figure 6. The drive signal is a waveform that is repeated every period T. Period T includes a period T1 and a period T2 that is after period T1 and 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 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 light L is in the second position.

[0053] The drive signal's current value changes from a first current value A1 to a second current value A2 during the first period TA1 of the period T1. Here, the intermediate position 0 between the first current value A1 and the second current value A2 is the position where the current value is 0. The drive signal's current value changes linearly from the first current value A1 to the second current value A2 as time progresses during the first period TA1. That is, at the start of the first period TA1, the drive signal's current value is the first current value A1, and thereafter the current value changes linearly from the first current value A1 to the second current value A2 at the end of the first period TA1. 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 6 illustrates a case where the first current value A1 is negative and the second current value A2 is positive.

[0054] The length of the first period TA1 corresponds to the natural frequency of the first oscillating part 21. The first oscillating part 21 refers to the part 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). In other words, the length of the first period TA1 corresponds 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.

[0055] The drive signal maintains a current value of a second current value A2 during the second period TB1 of the period T1. The second period TB1 is after the first period TA1 and is continuous with the first period TA1. It is preferable to increase the natural frequency of the first oscillating part 21 so that the first period TA1 can be shortened and the second period TB1 can be lengthened (for example, it can be longer than the first period TA1). It should be noted that "maintained at the second current value A2" is not limited to the current value not changing strictly from the second current value A2, but may also include the current value deviating from the second current value A2 within a predetermined range. The predetermined value here may be set arbitrarily, but for example it may be 10% of the second current value A2.

[0056] Thus, during period T1, the drive signal causes the current value to gradually change 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.

[0057] During the third period TA2 of the period T2, the current value of the drive signal changes from the second current value A2 to the first current value A1. The third period TA2 is after the second period TB1 and is a period that is continuous with the second period TB1. More specifically, during the third period TA2, the current value of the drive signal changes linearly over time from the second current value A2 to the first current value A1. That is, at the start of the third period TA2, the current value of the drive signal is the second current value A3, and thereafter the current value changes linearly from the second current value A2, reaching the first current value A1 at the end of the third period TA2.

[0058] The length of the third period TA2 corresponds to the natural frequency of the first oscillating 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 oscillating 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.

[0059] The drive signal maintains a current value of a 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. Also, 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. It is preferable to increase the natural frequency of the first oscillating part 21 so that the third period TA2 can be shortened and the fourth period TB2 can be lengthened (for example, it can be longer than the third period TA2). Note that "maintained at the first current value A1" is not limited to the current value not changing strictly from the first current value A1, but may also include the current value deviating from the first current value A1 within a predetermined range. The predetermined value here may be set arbitrarily, but for example it may be 10% of the first current value A1.

[0060] Thus, during period T2, the drive signal causes the current value to gradually change 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.

[0061] As described above, in this embodiment, the waveform of the drive signal is trapezoidal, and the values ​​of the first period TA1 and the third period TA2, during which the current value changes, correspond to the natural frequencies of the oscillating part 12A.

[0062] The dashed line in Figure 6 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. It is also 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.

[0063] [Oscillation Pattern] Next, we will explain the oscillation pattern of the first oscillation unit 21 due to the application of a drive signal. Figure 7 is a graph illustrating the uniaxial oscillation pattern of the optical unit.

[0064] As shown in Figure 7, 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 7, the oscillation pattern is shown by a solid line.

[0065] During the first period TA1, the drive signal changes in current value from a first current value A1 to a second current value A2. As a result, the displacement angle of the first oscillating part 21 changes from a first angle D1 to a second angle D2 during the first period TA1. 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.

[0066] During the second period TB1, the drive signal is maintained at a current value of the second current value A2. As a result, the displacement angle of the first oscillating part 21 is maintained at the second angle D2 during the second period TB1. Note that being maintained at the second angle D2 is not limited to the displacement angle not changing exactly from the second angle D2, but may also include the displacement angle deviating from the second angle D2 within a predetermined range. The predetermined value here can be set arbitrarily, but for example, it may be 10% of the second angle D2.

[0067] During the third period TA2, the drive signal changes in current value from the second current value A2 to the first current value A1. As a result, the displacement angle of the first oscillating part 21 changes from the second angle D2 to the first angle D1 during the third period TA2.

[0068] During the fourth period TB2, the drive signal is maintained at a current value of a first current value A1. As a result, the displacement angle of the first oscillating part 21 is maintained at a first angle D1 during the fourth period TB2. Note that being maintained at the first angle D1 is not limited to the displacement angle not changing exactly from the first angle D1, but may also include the displacement angle deviating 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.

[0069] Light L is irradiated during the second period TB1 and the fourth period TB2. Therefore, during the second period TB1, light L is irradiated onto the first oscillating part 21 held at the second angle D2, and the optical path of light L becomes the first position. During the fourth period TB2, light L is irradiated onto the first oscillating part 21 held at the first angle D1, and the optical path of light L shifts to the second position, causing the image to shift by half a pixel.

[0070] In an optical path control device 10 that shifts the optical path by oscillating an optical element 20, it is required to oscillate the optical element 20 stably. In this embodiment, by setting the lengths of the first period TA1 and the third period TA2 to values ​​corresponding to the natural frequency of the first oscillating part 21, vibration of the first oscillating part 21 in the second period TB1 and the fourth period TB2 is suppressed, and the first oscillating part 21 can be oscillated stably. That is, by setting the lengths of the first period TA1 and the third period TA2 to values ​​corresponding to the natural frequency of the first oscillating part 21, vibration of the first oscillating part 21 in the second period TB1 and the fourth period TB2 is suppressed, and the first oscillating part 21 can be oscillated stably. Therefore, the first oscillating part 21 can be oscillated at high speed and kept stably stationary, thereby suppressing image degradation.

[0071] Here, we have described the drive signal applied to the first actuator 25 as a drive signal applied from the drive circuit 16 to the actuator 12B. The same applies to the drive signal applied to the second actuator 26, so its explanation is omitted.

[0072] [Pixel operation by optical path control mechanism] The operation of the first and second oscillating parts 21 and 22 will be described below. Figure 8 is an explanatory diagram illustrating the two-axis oscillation pattern of the optical unit.

[0073] In the optical path control mechanism 12 of this embodiment, the first actuator 25 and the second actuator 26, which constitute the actuator 12B, each oscillate the first oscillating part 21 and the second oscillating part 22 so as to repeatedly change their attitude from a first angle D1 to a second angle D2 and from a second angle D2 to a first angle D1 around the first axis AX and the second axis BX, respectively, in response to the drive signal. 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 to the first position.

[0074] 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, making the image projected onto the screen higher resolution. Since the amount of optical axis shift is 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 amount of image shift is not limited to half a pixel, but 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 in accordance with the amount of image shift.

[0075] 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 8, 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.

[0076] Similarly, in operation state B, the image is displayed at image position P2, which is shifted by 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 by 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 by 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.

[0077] The oscillation patterns of the first oscillation unit 21 and the second oscillation unit 22 in the operation state of the pixels described above will now be explained. Figure 9 is a graph illustrating the two-axis oscillation pattern of the optical unit.

[0078] In the following explanation, 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) per unit of time when a drive signal is applied to the first actuator 25, and is shown by a solid line. The oscillation pattern of the second oscillation unit 22 refers to the displacement angle of the second oscillation unit 22 (angle around the second oscillation axis BX) per unit of time when a drive signal is applied to the second actuator 26, and is shown by a dotted line.

[0079] As shown in Figure 9, during the displacement period TA2-A, the drive signal applied to the first actuator 25 changes in current value from the second current value A2 to the first current value A1 (see Figure 6). As a result, the displacement angle of the first oscillating part 21 changes from the second angle D2 to the first angle D1 during the displacement period TA2-A. During the displacement period TA2-B, the drive signal applied to the second actuator 26 changes in current value from the second current value A2 to the first current value A1. As a result, the displacement angle of the second oscillating part 22 changes from the second angle D2 to the first angle D1 during the displacement period TA2-B.

[0080] Furthermore, during the displacement period TA1-C, the drive signal applied to the first actuator 25 changes in current value from a first current value A1 to a second current value A2. As a result, the displacement angle of the first oscillating part 21 changes from a first angle D1 to a second angle D2 during the displacement period TA1-C. During the displacement period TA1-D, the drive signal applied to the second actuator 26 changes in current value from a first current value A1 to a second current value A2. As a result, the displacement angle of the second oscillating part 22 changes from a first angle D1 to a second angle D2 during the displacement period TA1-D.

[0081] Displacement periods TA2-A, TA2-B, TA1-C, and TA1-D represent the transition periods to operating states A, B, C, and D, respectively, as explained in Figure 8. When the natural frequencies of the first oscillation unit 21 and the second oscillation unit 22 are the same, for example, the lengths of displacement periods TA2-A and TA2-B are the same. As a result, the lengths of display periods TB2-A and TB2-B are the same when maintaining the current, the image appears the same in operating states A and B, and the degradation of image quality is suppressed.

[0082] The above describes an example of a drive signal applied to the actuator and a swing pattern of the swinging part 12A corresponding to the drive signal in this embodiment. However, the drive signal and swing pattern are not limited to those described above and may be arbitrary.

[0083] <Frame division structure> Figure 10 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.

[0084] A subframe is a divided frame that contains some of the pixels from a single frame. In other words, a subframe is a divided frame that displays the image data of some of the pixels from the image data of each pixel displayed 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 10, one frame that makes up image data with a resolution of 8K is composed of multiple combinations of 4 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 make up 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 make up 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.

[0085] 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 time frame the frame is displayed. 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. When displaying moving images using this method of dividing into subframes, it is also required to display the moving image appropriately while displaying appropriate gradation. In response to this, in this embodiment, by setting the number of subframes in one frame based on the motion vector V of the motion region contained in the image to be displayed, it becomes possible to display the moving image appropriately while displaying appropriate gradation. This will be explained in detail below.

[0086] <How to display subframes> Figure 11 is an explanatory diagram illustrating an example of a subframe display method according to Embodiment 1. In Figure 11, as an example of a moving image, frames F1 to F4 show the state in which object 200 (airplane) passes through the space in which object 202 (building) is visible, 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 part of the target area, but the objects are not limited to these and may be arbitrary. In this embodiment, the objects are those that have been learned in advance and can move or change shape. The data of the objects is stored in the memory unit of the control unit 170.

[0087] When setting a subframe, the control unit 170 acquires the image data contained in the frame. Specifically, if the frame to be displayed is designated as the second frame, and the frame displayed before the second frame in chronological order 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 chronological order, but is not limited to that; it may be a frame displayed at any time before the second frame (for example, a frame several frames before the second frame). Also, multiple frames before the second frame may be designated as the first frame. In the example in Figure 11, when frame F2 is designated as 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.

[0088] 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 compares the images of the first frame and the second frame to calculate the target region and the motion vector of the target region. The control unit 170 may calculate the target region and motion vector using any method based on the image data of the first frame and the image data of the second frame, and may use known techniques. An example of a method for calculating the target region and motion vector will be described below. 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 area in the image of the first frame and the image of the second frame in which the same object is captured. In other words, the target region in the first frame refers to the region (pixel group) in the first frame that contains the object that is also included in the second frame, and the target region in the second frame refers to the region (pixel group) in the second frame that contains the object that is also included in the first frame. In the example in Figure 11, objects 200 and 202 are included in both the image of frame F1 and the image of frame F2. Therefore, in the example in Figure 11, the control unit 170 extracts the region (pixel group) in the image data of frame F1 that contains object 200 as the target region for object 200 in frame F1, and extracts the region (pixel group) in the image data of frame F2 that contains object 200 as the target region for object 200 in frame F2. Similarly, in the example shown in Figure 11, 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 will be considered the target area.

[0089] The control unit 170 compares the first frame and the second frame, extracts the target region, and then 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 11, the control unit 170 calculates a 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 a 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 the direction of movement (direction of motion). The direction of motion 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.

[0090] 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. If there are multiple motion regions, the motion vector V that maximizes the motion vector (amount of movement) V within each motion region is used to make the above determination. The threshold here can be set arbitrarily. In the example in Figure 11, 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 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 less than or equal to the threshold. Therefore, in the example in Figure 11, the number of subframes in frames F2 to F4 is greater than the number of subframes in frames F5 to F6.

[0091] Furthermore, if the motion vector V is greater than a threshold, the control unit 170 preferably sets the subframes such that all pixels included in the second frame are included in one of the respective subframes. That is, in the example in Figure 11, in frame F2, four subframes 2A, 2B, 2D, and 2C are set, and of the multiple pixels A, B, C, and D that make up frame F2, pixel A is included in subframe 2A, pixel B is included in subframe B, pixel C is included in subframe 2C, and pixel D is included in subframe 2D. The same applies to frames F3 and F4, so their explanation is omitted.

[0092] Furthermore, if 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 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 included in the subframes of the second frame are included in one of the subframes. That is, in the example in Figure 11, in frame F5, two subframes 5A and 5B are set, and of the multiple pixels A, B, C, and D that make up frame F5, pixel A is included in subframe 5A and pixel B is included in subframe 5B. Then, in frame F6, subframes 6D and 6C are set, and of the multiple pixels A, B, C, and D that make up frame F5, pixel D that 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 being on the same line (side by side), and combinations of pixel A and pixel D, and pixel B and pixel C are also possible.

[0093] In the example shown in Figure 11, the number of subframes (first predetermined number) when the motion vector V is greater than the threshold was 4, and the number of subframes (second predetermined number) when the motion vector V is less than or equal to the threshold was 2. 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 are set according to the number of pivot axes. In the example of this embodiment, the number of subframes is set to one of two types of numbers, the first predetermined number or the second predetermined number, but is not limited to these. For example, the number of subframes to be set may be set to any three or more types of numbers according to the motion vector V. In this case, it is preferable that the control unit 170 increases the number of subframes as the motion vector (amount of movement) V increases. For example, when the motion vector V is less than or equal to the first threshold, the number of subframes may be 1; when the motion vector V is greater than the first threshold and less than or equal to the second threshold which is higher than the first threshold, the number of subframes may be 2; and when the motion vector V is greater than the second threshold, the number of subframes may be 4.

[0094] Furthermore, in the example of 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 if the amount of movement is small, as the motion region increases.

[0095] After setting the number of subframes for the second frame, the control unit 170 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 image data during the display period of the subframe, for each subframe.

[0096] (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.

[0097] (Image display when the motion vector is greater than the threshold) Figure 12 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 for display. 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 digital 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 drive signal, causing the oscillating part 12A to oscillate. A detailed explanation follows below.

[0098] In the examples shown in Figures 11 and 12, 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 (60Hz) 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 (240Hz) for displaying the second frame (60Hz).

[0099] At this time, as shown in Figures 2, 11, and 12, the control circuit 14 generates a digital 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. In other words, as shown in Figure 11, when displaying subframe 2A, the drive circuit 16 applies a second current value A2 to the first actuator 25 and the second actuator 26. Then, as shown in Figure 12, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, and the image position P0 is shifted by 1 / 2 pixel in the direction of the first oscillation axis AX, resulting in operation state A. That is, the image is displayed at the image position P1, which is shifted by one ABXa in the ABX direction from the image position P0.

[0100] Subsequently, as shown in Figure 11, when displaying subframe 2B, the drive circuit 16 continues to apply the second current value A2 to the first actuator 25 and applies the first current value A1 to the second actuator 26. Then, as shown in Figure 12, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, setting the image position P1 to operation state B, which is shifted by 1 / 2 pixel in the direction of the first oscillation axis AX. That is, the image is displayed at image position P2, which is shifted by one ABXb in the ABX direction from image position P0.

[0101] Subsequently, as shown in Figure 11, when displaying subframe 2D, the drive circuit 16 stops applying the second current value A2 to the first actuator 25, changes it to the first current value A1, and continues to apply the first current value A1 to the second actuator 26. Then, as shown in Figure 12, the first actuator 25 swings the optical member 20 (see Figure 3) around the first oscillation axis AX, shifting the image position P2 by 1 / 2 pixel in the direction of the second oscillation axis BX, and putting it into operation D state. That is, the image is displayed at image position P3, which is shifted by one ABXd in the ABX direction from image position P0.

[0102] Subsequently, as shown in Figure 11, when displaying subframe 2C, the drive circuit 16 continues to apply the first current value A1 to the first actuator 25, and changes the application of the first current value A1 to the second actuator 26 to the second current value A2. Then, as shown in Figure 12, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, and the image position P3 is shifted by 1 / 2 pixel in the direction of the first oscillation axis AX, resulting in a C operation state. That is, the image is displayed at image position P4, which is shifted by one ABXc in the ABX direction from image position P0.

[0103] (Image display when the motion vector is below the threshold) Figures 13 and 14 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 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, and 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 digital 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 drive signal to oscillate the oscillating part 12A. A detailed explanation follows below.

[0104] As shown in Figures 11 and 13, 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 (60Hz) for displaying the second frame (here, frame F5). At this time, the time for displaying each subframe 5A and 5B is half the time (120Hz) for displaying frame F5 (60Hz). Subsequently, as shown in Figures 11 and 14, 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 (60Hz) for displaying the third frame (here, frame F6). In this case, the time it takes to display each subframe 6D and 6C is half the time it takes to display the second frame (60Hz) (120Hz).

[0105] At this time, as shown in Figures 2, 11, and 13, the control circuit 14 generates a digital 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. In other words, as shown in Figure 11, when displaying subframe 5A, the drive circuit 16 applies a second current value A2 to the first actuator 25 and the second actuator 26. Then, as shown in Figure 13, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, and the image position P0 is shifted by 1 / 2 pixel in the direction of the first oscillation axis AX, resulting in operation state A. That is, the image is displayed at the image position P1, which is shifted by one ABXa in the ABX direction from the image position P0.

[0106] Subsequently, as shown in Figure 11, when displaying subframe 5B, the drive circuit 16 continues to apply the second current value A2 to the first actuator 25 and applies the first current value A1 to the second actuator 26. 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 P1 to operation state B, which is shifted by 1 / 2 pixel in the direction of the first oscillation axis AX. That is, the image is displayed at image position P2, which is shifted by one ABXb in the ABX direction from image position P0.

[0107] Subsequently, as shown in Figure 11, when displaying subframe 6D, the drive circuit 16 stops applying the second current value A2 to the first actuator 25, changes it to the first current value A1, and continues to apply the first current value A1 to the second actuator 26. Then, as shown in Figure 14, the first actuator 25 swings the optical member 20 (see Figure 3) around the first oscillation axis AX, shifting the image position P2 by 1 / 2 pixel in the direction of the second oscillation axis BX, and putting it into operation D. That is, the image is displayed at image position P3, which is shifted by one ABXd in the ABX direction from image position P0.

[0108] Subsequently, as shown in Figure 11, when displaying subframe 6C, the drive circuit 16 continues to apply the first current A1 to the first actuator 25, and changes the applied current value A1 to the second actuator 26 to the second current value A2. Then, as shown in Figure 14, the second actuator 26 swings the optical member 20 around the second oscillation axis BX, and the image position P3 is shifted by 1 / 2 pixel in the direction of the first oscillation axis AX, resulting in a C operation state. That is, the image is displayed at image position P4, which is shifted by one ABXc in the ABX direction from image position P0.

[0109] As explained above, in this embodiment, the number of subframes in a frame is set based on the motion vector V of the motion region. By setting subframes in this way and displaying an image for each subframe, the desired gradation can be displayed appropriately. Furthermore, since the number of subframes is set from the motion vector V of the motion region, the number of subframes 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 moving image can be displayed appropriately. Moreover, in this embodiment, the number of subframes when the motion vector V is greater than the threshold is set to be greater than the number of subframes 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 frame rate can be increased by increasing the number of subframes, and the moving image can be displayed smoothly. On the other hand, when the number of subframes is large, the duration of one subframe becomes shorter, so the predetermined gradation must be displayed in a short time. In optical modulation elements using liquid crystals, even when a voltage is applied, the modulation rate of the liquid crystal element does not immediately change to a value corresponding to the applied voltage, but changes relatively slowly. Therefore, in short timeframes, it may not be possible to display the desired gradation, or the display position may shift while changing brightness to the next subframe period, potentially causing blurring and degrading resolution. In contrast, in this embodiment, when dealing with a still image with a low motion vector V, reducing the number of subframes suppresses the shifting of the display position while displaying the image appropriately, resulting in a richly graded image with minimal resolution degradation.

[0110] In the above explanation, the image position (image positions P1 to P4 in this example) was switched mechanically by the oscillating unit 12A, but the method of switching the image position is not limited to this. For example, the image position may be switched by a combination of liquid crystal elements and birefringent elements.

[0111] 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 15 is a schematic diagram showing another example of the order in which pixels are displayed. For example, as shown in Figure 15, the subframes may be set to display pixels A, D, B, and C in that order.

[0112] [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.

[0113] 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. In other words, 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 example, the image is divided into multiple blocks, a correlation calculation is performed between the first frame and the second frame for each block, and the motion vector V is calculated from the correlation value in the correlation calculation. Blocks in which the motion vector V is greater than a predetermined value may be calculated as motion regions. In addition, the motion regions, motion vector V, and amount of motion in Embodiment 2 may be obtained from an external device via a communication unit (not shown). Furthermore, the motion region is not limited to the region in which the motion vector V is generated, but may also be the region in which the amount of motion is generated.

[0114] (effect) As described above, the display device according to this embodiment includes a video signal processing circuit (processing unit) 160 that controls the display element 106 based on image data, and a control unit 170 that controls the video signal processing circuit (processing unit) 160. The control unit 170 obtains 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, and based on the amount of motion, sets the number of subframes for the second frame to display some of the pixels included in the image data of the second frame. The control unit 170 causes the video signal processing circuit (processing unit) 160 to control the display element 106 so that the subframes set for the second frame are displayed within the time it takes to display the second frame. As a result, it becomes possible to display moving images smoothly while displaying appropriate gradations.

[0115] Furthermore, in the display device according to this embodiment, the control unit 170 increases the number of subframes when the amount of motion is greater than a predetermined threshold, compared to the number of subframes when the amount of motion is less than or equal to the threshold. By increasing the number of subframes, the frame rate can be increased, and the moving image can be displayed smoothly.

[0116] Furthermore, in the display device according to this embodiment, the control unit 170 reduces the threshold value as the motion region, which is the area where motion occurs, becomes larger. Therefore, the degradation of the resolution of the moving image can be suppressed.

[0117] Furthermore, in the display device according to this embodiment, the control unit 170 sets the subframes so that all pixels included in the second frame are included in one of the respective subframes when it determines that the amount of motion is greater than a threshold, and sets the subframes so that only some of the pixels included in the second frame are included in one of the respective subframes when it determines that the amount of motion is less than or equal to a threshold. As a result, it becomes possible to display moving images smoothly while displaying appropriate gradations.

[0118] Furthermore, the display device according to this embodiment further includes a oscillating unit 12A having an optical element (optical part) 20 into which light L is incident, an actuator 12B capable of oscillating the oscillating unit 12A, and a drive unit that drives the actuator 12B in synchronization with the processing of the video signal processing circuit (processing unit) 160. As a result, it becomes possible to display moving images smoothly while displaying appropriate gradations.

[0119] Furthermore, the display method according to this embodiment includes the steps 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; setting the number of subframes for the second frame to display some of the pixels included in the image data of the second frame based on the amount of motion; and controlling the display element 106 so that the subframes set for the second frame are displayed within the time it takes to display the second frame. As a result, it becomes possible to display moving images smoothly while displaying appropriate gradations.

[0120] In the embodiment described above, the optical member 20 is pivotably supported 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, but the configuration is not limited to this.

[0121] 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.

[0122] Each component of the illustrated display device 1 is a functional concept and does not necessarily have to be physically configured as shown. In other words, the specific form of each device is not limited to that shown, and all or part of them may be functionally or physically distributed or integrated in any unit depending on the processing load and usage conditions of each device.

[0123] 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 by the cooperation of hardware or software. That is, these functional blocks can be realized in various forms by hardware alone, software alone, or a combination thereof.

[0124] The above-described components include those that are easily conceivable by 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. [Explanation of Symbols]

[0125] 1 Display device 10 Optical path control device 12. Optical path control mechanism 12A Swivel part 12B Actuator 14 Control circuits 16. Drive circuit (drive unit) 20 Optical components (optical parts) 21 First rocking part 22 Second rocking part 23 First shaft section 24 Second shaft section 25 First Actuator 26. Second Actuator 27 Support part 31 1st moving part 32 Second moving part 100 Irradiation device 106 display elements 160 Video signal processing circuit (processing section) 170 Control Unit AX First oscillating axis BX Second Oscillating Axis V motion vector

Claims

1. A processing unit that controls display elements based on image data, A control unit that controls the aforementioned processing unit, Equipped with, The control unit, The image data in the first frame and the second frame which is after the first frame The amount of motion is obtained from the aforementioned image data, Based on the amount of motion, the image data of the second frame is applied to the second frame. Set the number of subframes that display some of the pixels included. The processing unit controls the display element so that the subframe set for the second frame is displayed within the time period for displaying the second frame, and the number of subframes when the amount of motion is greater than a predetermined threshold is greater than the number of subframes when the amount of motion is less than or equal to the threshold. Display device.

2. The control unit increases the size of the motion region, which is the region where the amount of motion occurs, as the threshold value increases. Make it smaller. The display device according to claim 1.

3. The control unit, If it is determined that the amount of motion is greater than the threshold, the subframes are set so that all pixels included in the second frame are included in one of the respective subframes. If the amount of motion is determined to be less than or equal to the threshold, a portion of the image included in the second frame The subframes are configured such that only the elements are included in each of the subframes. Set The display device according to claim 1 or claim 2.

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 that drives the actuator in synchronization with the processing of the aforementioned processing unit, The display device according to claim 1 or claim 2, further comprising the above.

5. Image data in the first frame and in the second frame which is after the first frame A step of obtaining the amount of motion from the aforementioned image data, Based on the amount of motion, the image data of the second frame is applied to the second frame. The steps include setting the number of subframes that display some of the pixels included, The steps include controlling the display element so that the subframe set for the second frame is displayed within the time period for displaying the second frame, Includes, The number of subframes when the amount of motion is greater than a predetermined threshold is greater than the number of subframes when the amount of motion is less than or equal to the threshold. Display method.

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