Pixel expansion apparatus and projection display device

Abstract

The present application relates to a pixel expansion apparatus and a projection display device. The pixel expansion apparatus comprises: a first optical wedge used for receiving an incident beam; and a second optical wedge opposite to and spaced apart from the first optical wedge, wherein either of the second optical wedge and the first optical wedge moves back and forth along an optical path relative to the other, so that an emergent beam formed by the incident beam passing through the second optical wedge generates a preset displacement in a direction perpendicular to the optical path.

Description

Pixel expansion device and projection display equipment

[0001] Citation of Related Applications

[0002] This disclosure claims all rights and interests in the invention patent application entitled “Pixel expansion device and projection display device” with application number 202311343488.3 filed with the State Intellectual Property Office of the People’s Republic of China on October 16, 2023, and incorporates the entire contents of the application into this document by reference.

[0003] field

[0004] The present application relates to the field of projection display technology, and in particular to a pixel expansion device and a projection display apparatus.

[0005] background

[0006] In the projection display technology of Digital Light Processing (DLP), the Digital Micromirror Device (DMD) is a crucial optical component that directly determines the image resolution. At present, the display system with 4K resolution (the number of pixels per horizontal row reaches or approaches 4096) has gradually become the mainstream display technology, but the price of 4K resolution DMD chips is relatively high and is not applicable in many scenarios. Therefore, the Extended Pixel Resolution (XPR) technology can be used to achieve pixel expansion. XPR technology achieves higher resolution image display than the original DMD chip by offsetting the pixels (such as moving them in a directional manner by half a pixel), thereby achieving high-resolution display effects using low-resolution dimming devices.

[0007] The XPR technologies in related technologies include galvanometer solutions and plane mirror solutions. The principle of both solutions is to use external force to drive flat glass or plane mirrors to make fixed movements at a fixed frequency and angle to displace pixels, thereby achieving the effect of enhancing pixels. However, the energy utilization rate of the galvanometer solution is relatively low, that is, a displacement of half a pixel requires a large power consumption to achieve. The plane mirror solution has a greater impact on the optical path layout in the optical machine because it is placed at a certain angle to reflect light, and a very small swing angle can produce a displacement of half a pixel, which requires extremely high control accuracy and manufacturing accuracy of the device.

[0008] Overview

[0009] The purpose of this application is to provide a pixel expansion device and a projection display device, which can achieve accurate pixel expansion, improve display resolution, and have a simple structure and are easy to implement.

[0010] In a first aspect, an embodiment of the present application provides a pixel expansion device, comprising: a first optical wedge for receiving an incident light beam; a second optical wedge disposed opposite and spaced apart from the first optical wedge, wherein either the second optical wedge or the first optical wedge moves back and forth relative to the other along an optical path so that an outgoing light beam after the incident light beam passes through the second optical wedge produces a preset displacement in a direction perpendicular to the optical path.

[0011] In one possible implementation, the first optical wedge has a first inclined surface and a first flat surface set at a first preset angle, and the second optical wedge has a second inclined surface and a second flat surface set at a second preset angle, the second inclined surface is parallel to and opposite to the first inclined surface, and the first flat surface and the second flat surface are parallel to and opposite to each other; the incident light beam is incident from the first flat surface, and the outgoing light beam is emitted from the second flat surface.

[0012] In one possible implementation, the refractive index of the first optical wedge is the same as the refractive index of the second optical wedge.

[0013] In a possible implementation, the first preset angle and the second preset angle both have a value range of 0 to 20°.

[0014] In a possible implementation, a driving mechanism is further included, and the driving mechanism is connected to the first optical wedge or the second optical wedge to drive the first optical wedge or the second optical wedge to move back and forth along the optical path.

[0015] In one possible implementation, the driving mechanism includes a ring-shaped coil, multiple magnetic parts arranged on the outer periphery of the ring-shaped coil, and a bracket connected to the multiple magnetic parts, each magnetic part includes a pair of magnetic strips placed with opposite polarities, and the bracket is connected to the first optical wedge or the second optical wedge so that the first optical wedge or the second optical wedge moves back and forth along the optical path direction under the drive of electromagnetic force.

[0016] In a possible implementation, after the driving mechanism drives the first optical wedge or the second optical wedge to move to a preset position along the optical path, the wedge maintains the transient predetermined time and then moves in the opposite direction, wherein the duration of the transient predetermined time is greater than the duration of movement along the optical path.

[0017] In a possible implementation, the driving mechanism is an ultrasonic motor, which includes a piezoelectric ceramic component. The piezoelectric ceramic component is alternately powered on or off to drive the first optical wedge or the second optical wedge to move back and forth along the optical path.

[0018] In one possible implementation, the driving mechanism includes a first shape memory alloy wire and a second shape memory alloy wire, the first shape memory alloy wire is connected to the incident surface side of the first optical wedge, and the second shape memory alloy wire is connected to the exit surface side of the second optical wedge, and the first shape memory alloy wire and the second shape memory alloy wire are alternately energized or deenergized to drive the first optical wedge or the second optical wedge to move back and forth along the optical path direction.

[0019] In one possible implementation, the first optical wedge and the second optical wedge form a group of optical devices, there are two groups of optical devices, the optical paths of the two groups of optical devices are in the same direction, and the second optical wedge of one group of optical devices moves synchronously with the first optical wedge of the other group of optical devices.

[0020] In a second aspect, an embodiment of the present application provides a projection display device, comprising: a light source for generating an incident light beam; and a pixel expansion device as described above, arranged in the light path of the light source.

[0021] Embodiments of the present application provide a pixel expansion device and projection display apparatus, comprising: a first optical wedge for receiving an incident light beam; and a second optical wedge spaced apart from and opposed to the first optical wedge. Either the second optical wedge or the first optical wedge reciprocates relative to the other along the optical path, causing the incident light beam, after passing through the second optical wedge, to produce a predetermined displacement perpendicular to the optical path. Thus, by using the first and second optical wedges spaced apart from each other and either the second optical wedge or the first optical wedge reciprocating relative to the other along the optical path, the exiting light beam can be displaced perpendicular to the optical path by a predetermined amount relative to the incident light beam, thereby achieving precise pixel expansion and improving display resolution. The device also features a simple structure and is easily implemented.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly describes the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below represent some embodiments of the present application. A person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In addition, identical components are denoted by the same reference numerals in the drawings, and the drawings are not drawn to scale.

[0024] FIG1 is a schematic diagram showing the optical path of a pixel expansion device provided by an embodiment of the present application at time T0;

[0025] FIG2 is a schematic diagram showing the optical path of the pixel expansion device shown in FIG1 at time T1;

[0026] FIG3 is a schematic structural diagram of a driving mechanism of the pixel expansion device shown in FIG1 ;

[0027] FIG4 is a schematic structural diagram of another driving mechanism of the pixel expansion device shown in FIG1 ;

[0028] FIG5 is a schematic structural diagram showing another driving mechanism of the pixel expansion device shown in FIG1 ;

[0029] FIG. 6 shows a comparison of driving currents of an ultrasonic motor or SMA and an XPR in related art.

[0030] Description of reference numerals:

[0031] 1. First optical wedge; 11. First inclined surface; 12. First flat surface; 2. Second optical wedge; 21. Second inclined surface; 22. Second flat surface; θ, vertex angle; 3. Driving mechanism;

[0032] 31. Ring coil; 32. Magnetic component;

[0033] 33. Stator; 34. Biasing elastic member; 35. Piezoelectric ceramic member; 36. Elastic body; 37. Mover;

[0034] 38. First shape memory alloy wire; 39. Second shape memory alloy wire;

[0035] 100, pixel expansion device; 200, light source; 201, incident light beam; 202, outgoing light beam.

[0036] Details

[0037] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0038] As shown in FIG. 1 and FIG. 2 , an embodiment of the present application provides a pixel expansion device, comprising a first optical wedge 1 and a second optical wedge 2 that are arranged opposite to and spaced apart from each other.

[0039] First optical wedge 1 is used to receive an incident light beam, and either second optical wedge 2 or first optical wedge 1 moves back and forth relative to the other along the optical path so that the outgoing light beam after the incident light beam passes through first optical wedge 1 and second optical wedge 2 produces a preset displacement in a direction perpendicular to the optical path.

[0040] An optical wedge, also known as a wedge mirror, refers to a prism with a very small apex angle, typically less than 1 / 10 of a radian. When light enters the optical wedge perpendicularly or nearly perpendicularly, the resulting deflection angle is very small and independent of the angle of incidence. In this embodiment, a first optical wedge 1 and a second optical wedge 2 are positioned opposite and spaced apart from each other. Either the second optical wedge 2 or the first optical wedge 1 moves back and forth relative to the other along the optical path. For example, the first optical wedge 1 remains stationary while the second optical wedge 2 moves back and forth relative to the first optical wedge 1, or the second optical wedge 2 remains stationary while the first optical wedge 1 moves back and forth relative to the second optical wedge 2. In this way, after the incident light beam passes through the first and second optical wedges 1 and 2, the outgoing light beam experiences a predetermined displacement perpendicular to the optical path. This predetermined displacement can be half a pixel, thereby converting a single pixel into two pixels with a half-pixel spacing, thereby achieving higher-resolution image display using a low-resolution dimming device.

[0041] It is understandable that the preset displacement is not limited to half a pixel, and can also be 1 pixel or 1 / 4 pixel, etc., depending on the specific application scenario, which will not be elaborated here.

[0042] Furthermore, because the pixel expansion device in this embodiment operates by causing either second optical wedge 2 or first optical wedge 1 to move back and forth relative to the other along the optical path to achieve linear displacement of pixels, no aberrations such as distortion will be produced in the imaging. Furthermore, the first optical wedge 1 and the second optical wedge 2 have simple structures, and an external force only needs to drive either the first optical wedge 1 or the second optical wedge 2 to perform reciprocating linear motion in one direction to achieve two-way pixel displacement. This makes drive control simple and easy to implement.

[0043] The pixel expansion device provided in an embodiment of the present application includes a first optical wedge 1 and a second optical wedge 2 arranged in a spaced relationship with each other. The first optical wedge 1 is used to receive an incident light beam. Either the second optical wedge 2 or the first optical wedge 1 moves back and forth relative to the other along the optical path. After the incident light beam passes through the second optical wedge 2, the outgoing light beam experiences a predetermined displacement in a direction perpendicular to the optical path, thereby expanding the resolution of the incident light beam. Thus, by having the first optical wedge 1 and the second optical wedge 2 arranged in a spaced relationship with each other, and either the second optical wedge 2 or the first optical wedge 1 moving back and forth relative to the other along the optical path, the outgoing light beam experiences a predetermined displacement in a direction perpendicular to the optical path relative to the incident light beam, thereby expanding the resolution of the incident light beam. This allows for precise pixel expansion and improved display resolution, while maintaining a simple and easy-to-implement structure.

[0044] In some embodiments, first optical wedge 1 has a first inclined surface 11 and a first flat surface 12 set at a first preset angle, and second optical wedge 2 has a second inclined surface 21 and a second flat surface 22 set at a second preset angle. Second inclined surface 21 is parallel to and opposite to first inclined surface 11, and first flat surface 12 and second flat surface 22 are parallel to and opposite to each other. An incident light beam enters first flat surface 12, and an outgoing light beam exits second flat surface 22.

[0045] As shown in Figures 1 and 2, first optical wedge 1 has a first inclined surface 11, and second optical wedge 2 has a second inclined surface 21. Second inclined surface 21 is parallel to and spaced from first inclined surface 11. First optical wedge 1 also includes a first flat surface 12. First inclined surface 11 forms a first predetermined angle with first flat surface 12, which represents the vertex angle of first optical wedge 1. An incident light beam enters the flat surface perpendicularly or nearly perpendicularly and is deflected from first inclined surface 11 before exiting. Second optical wedge 2 also includes a second flat surface 22. Second inclined surface 21 forms a second predetermined angle with second flat surface 22, which represents the vertex angle of second optical wedge 2. Second inclined surface 21 is parallel to and opposite to first inclined surface 11, and first flat surface 12 and second flat surface 22 are parallel to each other. That is, the first optical wedge 1 and the second optical wedge 2 are placed in different directions. The incident light beam enters the first flat surface 12, exits the first inclined surface 11, and then enters the second inclined surface 21 where it is deflected. Finally, it is emitted from the second flat surface 22 in a direction parallel to the incident light beam, and the exiting light beam is offset by half a pixel in a direction perpendicular to the optical path.

[0046] It is understood that the vertex angle of the first optical wedge 1 and the vertex angle of the second optical wedge 2 can be the same or different. Optionally, the vertex angle of the first optical wedge 1 and the vertex angle of the second optical wedge 2 are the same. In this case, the structure and geometric dimensions of the first optical wedge 1 and the second optical wedge 2 are the same, and only the placement direction is different, which can save design costs and material storage costs. In addition, the incident light beam can be incident on the first flat surface or the first inclined surface perpendicularly, or at a certain angle. Correspondingly, the outgoing light beam can be emitted from the second flat surface or the second inclined surface. When the incident light beam is incident perpendicularly on the first flat surface and emerges from the second flat surface, the structure is more compact and the volume is smaller.

[0047] In some embodiments, the refractive index of first optical wedge 1 is the same as the refractive index of second optical wedge 2. When first optical wedge 1 and second optical wedge 2 are made of the same material, their refractive indices are also the same. Alternatively, first optical wedge 1 and second optical wedge 2 can both be made of K9 glass or UV fused silica, thereby reducing material storage costs.

[0048] Furthermore, the displacement of either second optical wedge 2 or first optical wedge 1 relative to the other along the optical path is Δx, the predetermined displacement of the outgoing light beam in a direction perpendicular to the optical path is Δy, and the following conditions are satisfied:

[0049] Δy=(n−1)*θ*Δx, where n is the refractive index of the first optical wedge 1 or the second optical wedge 2 , and θ is the first preset angle or the second preset angle.

[0050] The first preset angle or the second preset angle is the vertex angle θ, both ranging from 0 to 20°. When the vertex angle is small, the angle is approximately equal to the sine value. Optionally, the first preset angle and the second preset angle are any one of 5°, 10°, and 15°. The displacement Δx of either second optical wedge 2 or first optical wedge 1 relative to the other along the optical path is a known design value, and θ is a known design value. When the preset displacement Δy is half a pixel, the refractive indices of first optical wedge 1 and second optical wedge 2 can be solved. Alternatively, when the refractive indices of first optical wedge 1 and second optical wedge 2 are known design values, and when the preset displacement Δy is half a pixel, the displacement Δx of second optical wedge 2 relative to first optical wedge 1 along the optical path can be solved, thereby designing the internal optical path layout of the pixel expansion device.

[0051] In some embodiments, the pixel expansion device further includes a drive mechanism 3 connected to the second optical wedge 2 to drive the first optical wedge 1 or the second optical wedge 2 to reciprocate along the optical path. Drive mechanism 3 can be any of an electromagnetic linear motor, an ultrasonic motor, or a shape memory alloy (SMA) drive, each of which is described below with reference to specific embodiments.

[0052] In some embodiments, the driving mechanism 3 includes a ring-shaped coil 31, multiple magnetic parts 32 arranged on the outer periphery of the ring-shaped coil 31, and a bracket connected to the multiple magnetic parts 32, each magnetic part 32 includes a pair of magnetic strips placed with opposite polarities, and the bracket is connected to the first optical wedge 1 or the second optical wedge 2 so that the first optical wedge 1 or the second optical wedge 2 moves back and forth along the optical path direction under the drive of electromagnetic force.

[0053] As shown in Figure 3, the annular coil 31 is rectangular or square in shape, with a magnetic member 32 positioned on each of its four outer sides. A bracket (not shown) is connected to the multiple magnetic members 32 at one end and to the second optical wedge 2 at the other end. Each magnetic member 32 comprises a pair of oppositely polarized magnetic strips. Within the pair, the north pole of one strip is positioned adjacent to the south pole of the other strip, and the north poles of the two magnetic members 32 corresponding to two opposing sides are positioned corresponding to the south poles of the other pair. According to Ampere's law, when current flows through the annular coil 31 in a certain direction, the electromagnetic forces generated by the two magnetic members 32 corresponding to the two opposing sides are in the same direction, i.e., perpendicular to the paper in Figure 3. The combined electromagnetic forces generated by the four magnetic members 32 corresponding to the four sides jointly drive the second optical wedge 2 to move along the optical path. When current flows through the annular coil 31 in the opposite direction, the combined electromagnetic forces become opposite, thereby driving the second optical wedge 2 to move in the opposite direction along the optical path.

[0054] In related art, multiple coils are arranged in a ring shape, with magnetic members 32 positioned on the inner circumference of each coil. This renders the ends of the coils ineffective in the magnetic field and increases resistance. In this embodiment, however, because the ring coil 31 is annular and multiple magnetic members 32 are positioned on the outer circumference of the ring coil 31, the entire ring coil 31 is essentially functional in the magnetic field. This results in a larger overlap area between the magnetic members 32 and the ring coil 31, and higher electromagnetic utilization efficiency.

[0055] In some embodiments, after driving mechanism 3 drives first optical wedge 1 or second optical wedge 2 to a preset position along the optical path, it maintains the position for a predetermined transient time before moving in the opposite direction. The predetermined transient time is longer than the duration of the movement along the optical path. This configuration can significantly reduce power consumption.

[0056] Due to the human eye's persistence of vision, when a pixel moves from left to right, if it moves slowly, it will appear to the eye as motion; if it moves quickly, it will appear as a straight line. To enhance the pixel, the eye must neither perceive motion nor a straight line. Therefore, the duration of the movement must be minimized, with the left and right ends remaining for a relatively long time. This way, the eye sees neither movement nor a straight line, but only one pixel on each side. This effectively transforms one pixel into two, achieving the enhanced effect. Therefore, the first optical wedge 1 or the second optical wedge 2 spends 90% of its time in a transient state during a motion cycle. It then reverses to its initial position and remains there for a preset time, completing a motion cycle. Since the pixel spends 90% of its time at the left and right ends during a motion cycle, power consumption can be significantly reduced.

[0057] In one example, drive mechanism 3 is an ultrasonic motor including a piezoelectric ceramic element 35. Piezoelectric ceramic element 35 is alternately energized and de-energized to drive first optical wedge 1 or second optical wedge 2 to reciprocate along the optical path. For ease of illustration, this embodiment of the present application uses the example of drive mechanism 3 driving second optical wedge 2 to reciprocate relative to first optical wedge 1 along the optical path.

[0058] Specifically, the ultrasonic motor also includes a stator 33, a biasing elastic member 34, an elastic body 36, and a mover 37. The biasing elastic member 34 is arranged between one side of the stator 33 and the piezoelectric ceramic member 35. The elastic body 36 is arranged between the piezoelectric ceramic member 35 and the mover 37. The mover 37 is connected to the second optical wedge 2. When the piezoelectric ceramic member 35 is energized, it generates ultrasonic vibrations to drive the second optical wedge 2 to move back and forth along the optical path.

[0059] As shown in Figure 4 , biasing spring 34 is a compressible spring. Elastic body 36 can be made of silicone, rubber, or other materials. Mover 37 can be made of a wear-resistant material, such as copper. In one example, a micro-unit mass is mounted on elastic body 36. Since biasing spring 34 is located on one side of stator 33, energizing piezoelectric ceramic 35 generates ultrasonic vibrations, which drive the micro-unit mass on elastic body 36 into elliptical motion, resulting in displacement in the X and Y directions. The Y displacement is absorbed by elastic body 36, while the X displacement drives second optical wedge 2 along the optical path.

[0060] Furthermore, after second optical wedge 2 moves to a preset position along the optical path, piezoelectric ceramic component 35 is de-energized. Biasing elastic component 34, elastic body 36, and friction member drive second optical wedge 2 to maintain the preset position for a transient predetermined time. Then, piezoelectric ceramic component 35 is energized to drive second optical wedge 2 to move in the opposite direction.

[0061] After the second optical wedge 2 moves to a preset position along the optical path, the piezoelectric ceramic element 35 is de-energized. The pressure from the biasing spring element 34 and the friction between the mover 37 and the elastic body 36 keep the second optical wedge 2 relatively stationary in the de-energized state, creating a self-locking characteristic. This keeps the second optical wedge 2 stationary in the preset position for a predetermined period of time. The piezoelectric ceramic element 35 is then energized, driving the second optical wedge 2 in the reverse direction, completing one motion cycle. This cycle repeats, and the second optical wedge 2 spends 90% of its time in a transient state during each motion cycle. Therefore, the ultrasonic motor's power consumption is zero for a significant period during this process, significantly reducing the ultrasonic motor's power consumption.

[0062] Because the second optical wedge 2 is in a transient state for 90% of the time during a motion cycle to achieve the effect of enhancing resolution, the second optical wedge 2 is in a zero power state for a large period of time during the overall reciprocating motion process. Compared with the XPR technical solution in the related art, the power consumption is greatly reduced.

[0063] In another example, the driving mechanism 3 includes a first shape memory alloy wire 38 and a second shape memory alloy wire 39, wherein the first shape memory alloy wire 38 is connected to the incident surface side of the first optical wedge 1, and the second shape memory alloy wire 39 is connected to the exit surface side of the second optical wedge 2, and the first shape memory alloy wire 38 and the second shape memory alloy wire 39 are alternately energized or de-energized to drive the first optical wedge 1 or the second optical wedge 2 to move back and forth along the optical path direction.

[0064] Specifically, drive mechanism 3 also includes a pair of stators 33 spaced apart from each other. Stators 33 are disposed on one side of the incident surface of first optical wedge 1 and on the other side of the exit surface of second optical wedge 2, respectively. A first shape memory alloy wire 38 is connected between stator 33 and the incident surface of first optical wedge 1, and a second shape memory alloy wire 39 is connected between stator 33 and the exit surface of second optical wedge 2. First shape memory alloy wire 38 and second shape memory alloy wire 39 are alternately energized or deenergized to drive first optical wedge 1 or second optical wedge 2 to reciprocate along the optical path. For ease of explanation, this embodiment of the present application is described using the example of drive mechanism 3 driving second optical wedge 2 to reciprocate relative to first optical wedge 1 along the optical path.

[0065] Furthermore, after the second optical wedge 2 moves to the preset position along the optical path, the first shape memory alloy wire 38 is de-energized. After the second optical wedge 2 remains at the preset position for a transient predetermined time, the second shape memory alloy wire 39 is energized to drive the second optical wedge 2 to move in the opposite direction.

[0066] As shown in Figure 5, the length of the first or second shape memory alloy wire 38, 39, shortens after being energized and heated, but remains shortened after being de-energized and cooled. Thus, when the second shape memory alloy wire 38 is energized and shortened, it drives the second optical wedge 2 to the right to a preset position. After this, the second shape memory alloy wire 38 is de-energized, placing the second optical wedge 2 in a transient state (stopped motion) while simultaneously lengthening the first shape memory alloy wire 38. After a certain period of time, the first shape memory alloy wire 39 is energized and shortened, driving the second optical wedge 2 back to its initial position to the left while also lengthening the second shape memory alloy wire 38. In this manner, the first and second shape memory alloy wires 38, 39 alternate. Because the second optical wedge 2 spends 90% of its time in the transient state during a motion cycle to enhance resolution, the second optical wedge 2 spends a significant portion of its reciprocating motion in a zero-power state, significantly reducing power consumption compared to the XPR solution in the related art.

[0067] In some embodiments, the first optical wedge 1 and the second optical wedge 2 form a group of optical devices, the number of optical devices is two groups, the optical paths of the two groups of optical devices are in the same direction, and the second optical wedge 2 of one group of optical devices moves synchronously with the first optical wedge 1 of the other group of optical devices.

[0068] As previously mentioned, a set of optical devices, consisting of a first wedge 1 and a second wedge 2, can achieve a 2-way pixel shift in one direction. By adding another set of optical devices along this optical path, with the second wedge 2 of one set synchronized with the first wedge 1 of the other set, when the second wedge 2 of one set moves in the X direction relative to the first wedge 1 of the other set, a pixel shift occurs in the Y direction. Simultaneously, the first wedge 1 of the other set also moves in the Y direction. This means that when the first wedge 1 of the other set moves in the Y direction relative to the second wedge 2 of the other set, a pixel shift occurs in the X direction, achieving a 2-way pixel shift in the other direction. The two 2-way approaches can then be combined to create a 4-way pixel shift. This means that one pixel can shift four pixels, each spaced a half-pixel apart, with the centers of the four pixels connected to form a rectangle. Whether 2-way or 4-way is used is determined by the digital micromirror device (DMD) chip, digital light processing (DLP) chip, or spatial light modulator chip.

[0069] Figure 6 compares the driving currents of an ultrasonic motor or SMA and a related-art XPR. As shown in Figure 6(b), in the related-art XPR solution, the drive mechanism 3 constantly outputs driving current, resulting in high power consumption. In contrast, in Figure 6(a), the ultrasonic motor or SMA, when used as the drive mechanism 3, only needs to output driving current at certain moments when it reaches the preset position, remaining in a transient state for the majority of the time, significantly reducing power consumption.

[0070] In addition, embodiments of the present application further provide a projection display device, comprising: a light source 200 for generating an incident light beam 201; and the aforementioned pixel expansion device 100, disposed in the optical path of the light source 200. The projection display device can be applied to projectors, liquid crystal on silicon display systems, liquid crystal display systems, and micro-LED display systems.

[0071] It should be noted that references in this specification to "one embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not necessarily every embodiment includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not.

[0072] It should be readily understood that “on,” “above,” and “over” in this disclosure should be interpreted in the broadest manner, such that “on” means not only “directly on something,” but also includes “on something” with intervening features or layers therebetween, and “above” or “over” includes not only the meaning of “above” or “over,” but also includes “above” or “over” with no intervening features or layers therebetween (i.e., directly on something).

[0073] Additionally, spatially relative terms, such as "below," "beneath," "beneath," "above," and the like, may be used herein for ease of description to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be in other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A pixel expansion device, characterized in that: include: A first optical wedge, used for receiving an incident light beam; A second optical wedge is arranged opposite to and spaced from the first optical wedge, and either the second optical wedge or the first optical wedge moves back and forth relative to the other along the optical path so that an outgoing optical beam after the incident optical beam passes through the first optical wedge and the second optical wedge generates a preset displacement in a direction perpendicular to the optical path.

2. The pixel expansion device according to claim 1, characterized in that: The first optical wedge remains stationary, and the second optical wedge moves back and forth along the optical path relative to the first optical wedge; or the second optical wedge remains stationary, and the first optical wedge moves back and forth along the optical path relative to the second optical wedge.

3. The pixel expansion device according to claim 1 or 2, characterized in that: The first optical wedge has a first inclined surface and a first flat surface set at a first preset angle, the second optical wedge has a second inclined surface and a second flat surface set at a second preset angle, the second inclined surface is parallel to and opposite to the first inclined surface, and the first flat surface is parallel to and opposite to the second flat surface; The incident light beam is incident from the first flat surface, and the outgoing light beam is outgoing from the second flat surface.

4. The pixel expansion device according to claim 3, characterized in that: The first preset angle is the vertex angle of the first optical wedge, and the second preset angle is the vertex angle of the second optical wedge.

5. The pixel expansion device according to claim 3 or 4, characterized in that: The incident light beam is incident from the first straight surface, emitted from the first inclined surface, and then enters the second inclined surface to be deflected, and finally emitted from the second straight surface in a direction parallel to the incident light beam.

6. The pixel expansion device according to any one of claims 3 to 5, characterized in that: The movement amount of either the second optical wedge or the first optical wedge relative to the other along the optical path direction is Δx, the preset displacement amount of the outgoing light beam in the direction perpendicular to the optical path direction is Δy, and the following conditions are satisfied: Δy=(n-1)*θ*Δx, where n is the first optical wedge or the second The refractive index θ of the optical wedge is the first preset angle or the second preset angle.

7. The pixel expansion device according to any one of claims 1 to 6, characterized in that: The refractive index of the first optical wedge is the same as the refractive index of the second optical wedge.

8. The pixel expansion device according to any one of claims 3 to 6, characterized in that: The value range of the first preset angle and the second preset angle are both 0 to 20 degrees.

9. The pixel expansion device according to any one of claims 1 to 8, characterized in that: It also includes a driving mechanism, which is connected to the first optical wedge or the second optical wedge to drive the first optical wedge or the second optical wedge to move back and forth along the optical path direction.

10. The pixel expansion device according to claim 9, characterized in that: The driving mechanism includes a ring-shaped coil, a plurality of magnetic parts arranged on the outer peripheral side of the ring-shaped coil, and a bracket connected to the plurality of magnetic parts, each of the magnetic parts includes a pair of magnetic strips placed with opposite polarities, and the bracket is connected to the first optical wedge or the second optical wedge so that the first optical wedge or the second optical wedge moves back and forth along the optical path direction under the drive of electromagnetic force.

11. The pixel expansion device according to claim 10, characterized in that: Each of the magnetic parts includes a pair of magnetic strips with opposite polarities, wherein the N pole of one magnetic strip is adjacent to the S pole of the other magnetic strip, and the N poles of a pair of magnetic strips in two magnetic parts corresponding to two opposite sides are respectively arranged corresponding to the S poles of the other pair of magnetic strips.

12. The pixel expansion device according to any one of claims 9 to 11, characterized in that: After the driving mechanism drives the first optical wedge or the second optical wedge to move to a preset position along the optical path direction, the first optical wedge or the second optical wedge is kept in a transient preset time and then moves in the reverse direction, wherein the duration of the transient preset time is greater than the duration of movement along the optical path direction.

13. The pixel expansion device according to claim 12, characterized in that: The first optical wedge or the second optical wedge is in a transient state for 90% of the time in a movement cycle, and then the first optical wedge or the second optical wedge moves in the opposite direction to an initial position, and completes a movement cycle after staying for a preset time.

14. The pixel expansion device according to any one of claims 9 to 13, characterized in that: The driving mechanism is an ultrasonic motor, and the ultrasonic motor includes a piezoelectric ceramic component. The piezoelectric ceramic component is alternately powered on or off to drive the first optical wedge or the second optical wedge to move back and forth along the optical path direction.

15. The pixel expansion device according to claim 14, characterized in that: The ultrasonic motor further comprises a stator, a biasing elastic member, an elastic body and a mover, wherein the biasing elastic member is arranged between one side of the stator and the piezoelectric ceramic member, the elastic body is arranged between the piezoelectric ceramic member and the mover, and the mover is connected to the second optical wedge.

16. The pixel expansion device according to any one of claims 9 to 13, characterized in that: The driving mechanism includes a first shape memory alloy wire and a second shape memory alloy wire, the first shape memory alloy wire is connected to one side of the incident surface of the first optical wedge, the second shape memory alloy wire is connected to one side of the exit surface of the second optical wedge, and the first shape memory alloy wire and the second shape memory alloy wire are alternately powered on or off to drive the first optical wedge or the second optical wedge to move back and forth along the optical path direction.

17. The pixel expansion device according to claim 16, characterized in that: The driving mechanism also includes a pair of stators arranged at intervals, and the pair of stators are respectively arranged on one side of the incident surface of the first optical wedge and one side of the exit surface of the second optical wedge, the first shape memory alloy wire is connected between the stator and the incident surface of the first optical wedge, and the second shape memory alloy wire is connected between the stator and the exit surface of the second optical wedge.

18. The pixel expansion device according to any one of claims 1 to 17, characterized in that: The first optical wedge and the second optical wedge form a group of optical devices, the number of the optical devices is two groups, the optical path directions of the two groups of optical devices are the same, and the second optical wedge of one group of optical devices moves synchronously with the first optical wedge of the other group of optical devices.

19. The pixel expansion device according to claim 18, characterized in that: The first optical wedge and the second optical wedge of a group of optical devices can complete the pixel displacement in one direction in a 2-way manner. Another group of optical devices is added in the direction of the optical path, so that the second optical wedge of one group of optical devices keeps synchronous movement with the first optical wedge of another group of optical devices. Then, when the second optical wedge in one group of optical devices moves along the X direction relative to the first optical wedge of the group, pixel displacement will be generated in the Y direction. At the same time, the first optical wedge of the other group of optical devices also keeps synchronous movement along the Y direction, that is, when the first optical wedge of the other group of optical devices moves along the Y direction relative to the second optical wedge of the group, pixel displacement will be generated in the X direction, thereby realizing the pixel displacement in another direction in a 2-way manner, and two 2-ways can be combined into a 4-way pixel displacement.

20. A projection display device, characterized in that: include: a light source for generating an incident light beam; and The pixel expansion device described in any one of claims 1 to 19 is arranged in the light path of the light source.

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