Laser projection device

Abstract

A laser projection device, comprising: a light source (30) configured to emit three-color light beams; a light valve (40), the light valve (40) comprising a plurality of micromirrors (41) distributed in an array, and the micromirrors (41) being configured to modulate and output the three-color light beams; a prism assembly (110), located between the light valve (40) and a projection lens (120), and configured to guide the light beams emitted by the light source (30) to be incident on the light valve (40) and guide the light modulated by the light valve (40) to the projection lens (120); a galvanometer (60), comprising an optical mirror (67) and located between the light valve (40) and the projection lens (120), wherein any side of the projection of the prism assembly (110) on a plane where the light valve (40) is located is not parallel to any side of each micromirror (41), any side of the projection of the optical mirror (67) on the plane where the light valve (40) is located is not parallel to any side of each micromirror (41), and the galvanometer (60) is configured to change, by means of the optical mirror (67) under the control of a current driving signal, positions of the light beams outputted by the light valve (40) at different moments; and the projection lens (120), configured to perform imaging on the basis of the light beams outputted by the galvanometer (60) at different moments.

Description

Laser projection device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 2024108706543, filed on June 28, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] Some embodiments of the present application relate to display technology. More specifically, to a laser projection device. BACKGROUND

[0004] In a laser projection device, in order to improve the resolution of the image, a pixel offset device such as a galvanometer is added. By rotating to different positions, the light beams transmitted through the lenses of the galvanometer are superimposed in a staggered manner, so as to superimpose the picture. By using the persistence of vision of the human eye, at least two pictures superimposed in a staggered manner will appear to be one picture, and the clarity of the picture is improved, and the resolution is improved in visual effect.

[0005] In related art, the arrangement direction of the galvanometer is consistent with the arrangement direction of the micro-mirror in the light valve, that is, any side of the projection of the galvanometer on the light valve is parallel to one side of the micro-mirror. However, due to the limited space above the inclined surface of the prism assembly, the installation space of the galvanometer is limited, and the galvanometer cannot be further lowered, so that the distance between the lens and the light valve is relatively long. Therefore, the above-mentioned laser projection device cannot be applied in some scenes with relatively small installation space, thereby resulting in poor versatility of the device. SUMMARY

[0006] Some embodiments of the present application provide a laser projection device, comprising:

[0007] a light source configured to emit three-color light beams; a light valve comprising a plurality of arrayed micro-mirrors configured to modulate and output the three-color light beams; a prism assembly located between the light valve and a projection lens, configured to guide the light beams emitted by the light source to be incident on the light valve, and guide the modulated light of the light valve to the projection lens; a galvanometer comprising an optical mirror surface, the galvanometer being located between the light valve and the projection lens, a projection of the prism assembly on a plane where the light valve is located is not parallel to any side of the micro-mirror, and a projection of the optical mirror surface on the plane where the light valve is located is not parallel to any side of the micro-mirror; the galvanometer is configured to change the position of the light beams output by the light valve at different times by the optical mirror surface under the control of a current driving signal; and a projection lens configured to image based on the light beams output by the galvanometer at different times.

[0008] In some embodiments, a side of a projection of the optical mirror on a plane where the light valve is located is parallel to a side of a projection of the prism assembly on the plane where the light valve is located.

[0009] In some embodiments, the galvanometer is further configured to, for each frame, control the light beam to shift to a corresponding position point under driving of the current driving signal; and a first trajectory formed by the corresponding position points of multiple frames is consistent with the contour of the micro mirror.

[0010] In some embodiments, the current driving signal includes a first current driving signal for controlling the light beam to shift along a first shift axis and a second current driving signal for controlling the light beam to shift along a second shift axis; and a phase difference between the first current driving signal and the second current driving signal is a first angle.

[0011] In some embodiments, the galvanometer further includes a circuit board, and the optical mirror is disposed on the circuit board; the circuit board is configured to drive the optical mirror to deflect based on the current driving signal, and the optical mirror is configured to control the light beam to shift to a corresponding position point through deflection of the optical mirror.

[0012] In some embodiments, each period of the first current driving signal corresponds to a first number of frames, and each frame corresponds to a position point in the first trajectory; the first current driving signal includes a plurality of driving data segments, each frame corresponds to a driving data segment, and each driving data segment corresponds to a signal value; and a variation of the signal values of adjacent two frames in the first current driving signal is used to control a shift amount of the corresponding position points of the light beam on the first shift axis.

[0013] In some embodiments, when a projection of the optical mirror on the plane where the light valve is located is parallel to a projection of the circuit board on the plane where the light valve is located in a reset state, the first current driving signal includes a second number of driving data segments with different signal values; the second number is half of the first number plus one; and the signal values of the driving data segments of adjacent frames in the first current driving signal are different.

[0014] In some embodiments, when a projection of the optical mirror on the plane where the light valve is located is parallel to a side of the contour of the micro mirror and is not parallel to any side of a projection of the circuit board on the plane where the light valve is located in a reset state, the first current driving signal includes a third number of driving data segments with different signal values; and the third number is half of the first number.

[0015] In some embodiments, the signal value is determined based on a first angle between a side of a projection of the galvanometer on the light valve and a corresponding side of the contour of the micro mirror and the first number.

[0016] In some embodiments, in the first current driving signal, the absolute values of the variation amounts of the signal values of any two adjacent frames in the same period are the same.

[0017] In some embodiments, in the first current driving signal, the absolute values of the variation amounts of the signal values of adjacent two frames in the same period are not completely the same.

[0018] In some embodiments, in each period of the first current driving signal, the first number of signal values are opposite to each other.

[0019] In some embodiments, the first current driving signal further comprises a plurality of first signal segments, the first signal segments are arranged between the current driving signal segments corresponding to adjacent frames, and the first signal segments are used to stabilize the deflection position of the light beam.

[0020] In some embodiments, the first signal segment is a 1.5-period sine wave. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate some embodiments of the present application or the implementation manners in the related art, the drawings needed to be used in the embodiment or related art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0022] FIG. 1 is a structural schematic diagram of a laser projection device according to some embodiments of the present application;

[0023] FIG. 2 is a structural schematic diagram of another laser projection device according to some embodiments of the present application;

[0024] FIG. 3 is a structural schematic diagram of a light valve according to some embodiments;

[0025] FIG. 4 is a structural schematic diagram of a light valve according to some embodiments;

[0026] FIG. 5 is a top view of a light valve, a galvanometer and a prism assembly according to some embodiments;

[0027] FIG. 6 is a front view of a light valve, a galvanometer and a prism assembly according to some embodiments;

[0028] FIG. 7 is a front view of a light valve, a galvanometer and a prism assembly according to some embodiments;

[0029] FIG. 8 is a top view of a light valve, a galvanometer and a prism assembly according to some embodiments;

[0030] FIG. 9 is a top view of a light valve, a galvanometer and a prism assembly according to some embodiments;

[0031] Figure 10a is a schematic diagram of refraction when the optical mirror is not deflected in some embodiments;

[0032] Figure 10b is a schematic diagram of refraction when the optical mirror is deflected in some embodiments;

[0033] Figure 11a is a schematic diagram of a structure of a galvanometer provided in some embodiments;

[0034] Figure 11b is a schematic diagram of a structure of another galvanometer provided in some embodiments;

[0035] Figure 12 is a schematic diagram of a structure of yet another galvanometer provided in some embodiments;

[0036] Figure 13 is a timing diagram of a current driving signal provided in some embodiments of the present application;

[0037] Figure 14a is a schematic diagram of a pixel shift process in some embodiments;

[0038] Figure 14b is a schematic diagram of a pixel shift process in some embodiments;

[0039] Figure 14c is a schematic diagram of a pixel shift process in some embodiments;

[0040] Figure 14d is a schematic diagram of a pixel shift process in some embodiments;

[0041] Figure 14e is a schematic diagram of a pixel shift process in some embodiments;

[0042] Figure 15 is a schematic diagram of a pixel shift process in some embodiments;

[0043] Figure 16 is a schematic diagram of a pixel shift process in some embodiments;

[0044] Figure 17 is a timing diagram of another current driving signal provided in some embodiments of the present application;

[0045] Figure 18 is a timing diagram of yet another current driving signal provided in some embodiments of the present application;

[0046] Figure 19 is a timing diagram of yet another current driving signal provided in some embodiments of the present application;

[0047] Figure 20a is a schematic diagram of a pixel shift process in some embodiments;

[0048] Figure 20b is a schematic diagram of a pixel shift process in some embodiments;

[0049] Figure 20c is a schematic diagram of a pixel shift process in some embodiments;

[0050] Figure 20d is a schematic diagram of a pixel shift process in some embodiments;

[0051] FIG. 21 is a timing diagram of yet another current drive signal, according to some embodiments;

[0052] FIG. 22 is a timing diagram of yet another current drive signal, according to some embodiments. DETAILED DESCRIPTION

[0053] For purposes of the present application, the following terms shall have the following meanings, unless otherwise indicated. It will be apparent to those skilled in the art that the exemplary implementations described herein can be practiced without

[0054] It should be noted that the foregoing summary of the application is intended by the applicant to be illustrative only and is not intended to be limiting upon the applicant's application. These terms are intended to cover a wide range of meanings and are not intended to be limited to the specific meanings unless otherwise indicated herein.

[0055] In addition, the terms "comprising" and "including" and any variations thereof are intended to cover a non-exclusive inclusion, such that a product or process that comprises a list of components or steps does not include only those components or steps but can include other components or steps not expressly listed or inherent to such product or process. Stated another way, there is a distinction between "comprising" and "including" and "consisting essentially of.

[0056] It should be noted that in the present application, when referring to the "outline", "projection", "edge" of a component (e.g., light valve, micromirror, prism assembly, optical mirror, circuit board, etc.) or a "trace" formed by a plurality of points, unless the context clearly dictates otherwise, it generally refers to its main or basic geometric shape feature or boundary. For example, when the outline or projection of a component is described as "rectangular", it should be understood that its actual shape can include chamfered corners, rounded corners or other non-ideal geometric deviations commonly seen in manufacturing or design, but it generally presents or approximates a rectangular feature. Similarly, when comparing the parallel or non-parallel relationship of two "edges", it generally refers to comparing the main extension direction or overall trend of the two edges, allowing for minor local bending, irregularities or details (such as chamfered corners) at the end points of the edges in the actual component.

[0057] FIG. 1 is a schematic diagram of a laser projection device, according to some embodiments. As shown in FIG. 1, the laser projection device can include a light source 30, which can include three-color laser chips integrated on a package unit, or three groups of monochromatic laser light emitting units. In some embodiments, the light source 30 can include at least one group of lasers. For example, each group of lasers can include a blue laser, a red laser, and a green laser.

[0058] In some embodiments, referring back to FIG. 1, the laser projection device can further comprise at least one laser driver component 20, wherein the at least one laser driver component 20 corresponds to the at least one group of lasers one-to-one. In some embodiments, referring back to FIG. 1, the laser projection device can further comprise a display control component 10. The display control component 10 can be a digital light processing chip (DLPC). In an example, the display control component 10 can be a DLPC 6540. In some embodiments, referring back to FIG. 1, the display control component 10 is configured to obtain a plurality of sub-images, the plurality of sub-images being obtained by decomposing a target image to be projected, the target image having a resolution greater than a resolution of the light valve, each sub-image having a resolution not greater than the resolution of the light valve. In some embodiments, referring back to FIG. 1, the display control component 10 is connected to each laser driver component 20 and configured to output at least one enable signal corresponding to each sub-image of the three primary colors one-to-one, transmit the at least one enable signal to the corresponding laser driver component 20, and output at least one laser current driving signal corresponding to each sub-image of the three primary colors one-to-one, transmit the at least one laser current driving signal to the corresponding laser driver component 20.

[0059] In some embodiments, referring back to FIG. 1, each laser driver component 20 is connected to the corresponding group of lasers and configured to provide the corresponding laser driving current to the lasers connected thereto in response to the received enable signal and the laser current driving signal. Each laser is configured to emit laser light under the driving of the laser driving current provided by the corresponding laser driver component 20.

[0060] In some embodiments, referring back to FIG. 1, the laser projection device further comprises a light valve 40, a galvanometer driving assembly 50, and a galvanometer 60. In some embodiments, the light valve 40 can be a digital micro-mirror device (DMD). The light valve can comprise an array of micro-mirrors, each of which corresponds to a pixel. The display control assembly 10 is further configured to control the micro-mirrors in the light valve 40 to flip according to the base color tone values of the pixels in each frame sub-image during the process that the three base color lights emitted by the lasers are sequentially irradiated to the light valve 40, so as to achieve modulation of the light. In some embodiments, the display control assembly 10 is further configured to transmit a galvanometer current driving signal corresponding to a sub-image to the galvanometer driving assembly during the process of projecting each frame sub-image. The galvanometer driving assembly 50 is configured to provide a galvanometer driving current to the galvanometer 60 under the control of the galvanometer current driving signal, so as to drive the galvanometer 60 to deflect. The galvanometer current driving signals corresponding to different frame sub-images are different. In some embodiments, the galvanometer 60 can be configured to offset different frame sub-images to different positions of the projection screen, so as to achieve superimposed display of the multiple frame sub-images, thereby achieving the effect of expanding the resolution of the projection device. In some embodiments, the galvanometer 60 can have four deflection positions, i.e., the galvanometer 60 can offset sub-images to four different positions of the projection screen. Alternatively, the galvanometer 60 can switch between two positions, i.e., have two deflection positions.

[0061] FIG. 2 is a structural schematic diagram of another laser projection device provided by some embodiments of the present application. In some embodiments, as shown in FIG. 2, the laser projection device can further comprise a reflection and light combination lens 70, a lens assembly 80, a diffusion wheel 90, a light guide tube 100, a total internal reflection (TIR) prism assembly 110, a projection lens 120, and a projection screen 130. In some embodiments, as shown in FIG. 2, the lens assembly 80 can comprise a first lens 801, a second lens 802, and a third lens 803. The projection process of the laser projection device will be exemplarily introduced below in combination with FIG. 2.

[0062] As shown in FIG. 2, the three-color laser beams emitted by the light source 30 are incident on the first lens 801 after being combined by the reflecting and combining lens 70, are diffused by the diffusion wheel 90, and are then totally reflected by the light guide tube 100. The diffusion wheel 90 can disperse the light spots. The blue laser, the red laser, and the green laser are then shaped by the second lens 802 and the third lens 803, are totally reflected by the prism assembly 110, are reflected by the light valve 40, and are then transmitted by the prism assembly 110. At this time, the galvanometer 60 arranged between the light valve 40 and the projection lens 120 deflects the lens under the control of the driving signal, so that the light beams reflected by the light valve 40 are displaced at different times, and the light spots are displaced. The light beams that are displaced alternately are incident on the projection lens 120, so that the images are also displaced and superimposed on the projection screen 130. Due to the persistence of vision of the human eye, if the displaced and superimposed images are associated, the information amount of the images is increased, the definition is improved, and the resolution is improved.

[0063] The light valve 40 is configured to modulate light. The light valve 40 can have a rectangular profile, as shown in FIGS. 3 and 4. The light valve 40 includes a plurality of micromirrors 41 arranged in an array. The micromirrors 41 can also have a rectangular profile. The micromirrors 41 can be arranged on the light valve 40 in various ways. For example, in FIG. 3, the arrangement direction of the micromirrors 41 is consistent with the arrangement direction of the light valve 40, that is, one side of the profile of the micromirrors 41 is parallel to one side of the profile of the light valve 40. For another example, in FIG. 4, the arrangement direction of the micromirrors 41 is 45° to the arrangement direction of the light valve 40, that is, the angle between one side of the profile of the micromirrors 41 and one side of the profile of the light valve 40 is 45°. As shown in FIG. 5, the prism assembly 110 is configured to reflect the light beams emitted by the light source, so that the reflected light beams are incident on the micromirrors 41 at a certain angle. To improve the reflection effect, the light beams can be controlled to be incident on the micromirrors 41 at 45°, that is, in the example of FIG. 3, the incident light rays are incident along the diagonal direction of the profile of the light valve 40, in the example of FIG. 4, the incident light rays are incident along the direction parallel to the side of the profile of the light valve 40, and in some embodiments, the light rays can be incident on the light valve 40 through the short side of the rectangular profile of the light valve 40 and then be incident on the micromirrors 41 in the direction parallel to the long side of the light valve 40.

[0064] As shown in FIGS. 3 and 4 in combination with FIG. 5, to achieve the incident angle of the light rays, the arrangement direction of the prism assembly 110 needs to be 45° to the arrangement direction of the micromirrors 41, that is, one side of the projection of the prism assembly 110 on the plane of the profile of the light valve 40 is 45° to one side of the profile of the micromirrors 41 in the light valve 40. For reference, FIG. 5 shows a top view of the light valve 40, the galvanometer 60, and the prism assembly 110.

[0065] Figure 6 is a front view of the light valve 40, the galvanometer 60 and the prism assembly 110 in some embodiments. As shown in Figure 6, the prism assembly 110 is arranged between the light valve 40 and the galvanometer 60. In the related art, the arrangement direction of the galvanometer 60 is consistent with the arrangement direction of the micromirror 41 in the light valve 40, i.e., the projection of the galvanometer 60 on the light valve 40 has any side parallel to a side of the micromirror 41. In combination with the above example in which the arrangement direction of the prism assembly 110 is 45° to the arrangement direction of the micromirror 41, as shown in Figure 5, the arrangement direction of the galvanometer 60 is consistent with the arrangement direction of the micromirror 41, and the prism assembly 110 (TIR prism) is arranged at 45°. In this way (see Figure 5), the diagonal line of the galvanometer 60 intersects the inclined surface of the prism assembly 110. Due to the limited space above the inclined surface of the prism assembly 110, as shown in Figure 6, the galvanometer 60 cannot fall further due to the installation space of the galvanometer 60, so that the distance H1 between the lens and the light valve 40 is relatively long, i.e., the back focal length of the lens is relatively long. In this way, the above laser projection device cannot be applied in some scenarios in which the installation space is relatively small, thereby resulting in poor versatility of the device.

[0066] Therefore, some embodiments of the present application provide a laser projection device. When the profile of the micromirror is not parallel to the projection of the prism assembly on the light valve, the arrangement direction of the galvanometer is arranged to be inconsistent with the arrangement direction of the micromirror. In this way, the arrangement direction of the galvanometer and the prism assembly can be adjusted flexibly, thereby reducing the installation space of the intersection position of the galvanometer and the prism assembly. In this way, the galvanometer 60 can fall towards the side close to the light valve during installation (viewing angle of Figure 6), thereby shortening the distance between the lens and the light valve, and thereby shortening the back focal length of the projection device, so as to improve the versatility of the device.

[0067] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail in some embodiments. Some embodiments below can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0068] FIG. 7 is a structural schematic diagram of a laser projection device according to some embodiments of the present application. As shown in FIG. 7, the laser projection device according to some embodiments includes a light source configured to emit a three-color light beam. Details can be referred to the above embodiments. The laser projection device can further include a light valve 40, where the light valve 40 includes a plurality of arrayed micro-mirrors 41 configured to modulate and output the three-color light beam. Details can be referred to some embodiments of FIG. 3 and FIG. 4. The laser projection device can further include a prism assembly 110 located between the light valve 40 and a projection lens 120, configured to guide the light beam emitted by the light source to the light valve 40 and guide the light modulated by the light valve 40 to the projection lens 120. The projection of the prism assembly 110 on the light valve 40 is a rectangle. The arrangement of the prism assembly 110 and the micro-mirrors 41 can include multiple modes, for example, one side of the projection of the prism assembly 110 on the light valve 40 is parallel to one side of the profile of the micro-mirrors 41; for another example, any side of the projection of the prism assembly 110 on the light valve 40 is not parallel to any side of the profile of the micro-mirrors 41. In some embodiments, one side of the projection of the prism assembly 110 on the light valve 40 is at an angle of 45° to one side of the profile of the micro-mirrors 41.

[0069] Continuing to refer to FIG. 7, the laser projection device can further include a galvanometer 60. As shown in FIG. 8, the galvanometer 60 includes an optical mirror 67. The galvanometer 60 is located between the light valve 40 and the projection lens 120. The profile of the optical mirror 67 is a rectangle, and the profile of the galvanometer 60 can also be a rectangle, or can be other shapes. For the convenience of the following description, the profile of the galvanometer 60 is exemplarily described as a rectangle. In some embodiments, the arrangement direction of the optical mirror can be consistent with the arrangement direction of the galvanometer, as shown in FIG. 11a. The galvanometer 60 is configured to change the position of the light beam output by the light valve 40 under the control of a current driving signal. The projection lens 120 is configured to image based on the light beams output by the galvanometer 60 at different times.

[0070] In some embodiments, if any side of the projection of the prism assembly 110 on the light valve 40 is not parallel to any side of the micro-mirrors 41, as shown in the top view of the prism assembly 110, the optical mirror 67 and the micro-mirrors 41 in FIG. 8, any side of the projection of the optical mirror 67 on the plane where the light valve 40 is located is not parallel to any side of the micro-mirrors 41. That is, if the arrangement direction of the prism assembly 110 is not consistent with the arrangement direction of the micro-mirrors 41, the arrangement direction of the optical mirror 67 is not consistent with the arrangement direction of the micro-mirrors 41. If the arrangement direction of the prism assembly 110 is consistent with the arrangement direction of the micro-mirrors 41, the arrangement direction of the galvanometer 60 is consistent with the arrangement direction of the micro-mirrors 41. The prism assembly 110 can include a triple prism.

[0071] It should be noted that the arrangement direction of the two devices in some embodiments is consistent, and in the example in which the projection of the optical mirror 67, the light valve 40, the micromirrors 41 under the light valve 40, and the prism assembly 110 are all rectangular, it can refer to that one side of the device A is parallel to one side of the device B. Conversely, the arrangement direction of the two devices in some embodiments is inconsistent, and it can refer to that any side of the device A is not parallel to any side of the device B. The arrangement direction of the two devices in some embodiments is different by a second angle, which refers to that the angle between one side of the device A and one side of the device B is the second angle, and the second angle is 0-90°. In some embodiments, the arrangement direction of the optical mirror 67 is different from the arrangement direction of the micromirror 41 by 20°, and the angle between one side of the profile of the optical mirror 67 and one side of the micromirror 41 is 20°.

[0072] In some embodiments, as shown in FIG. 6, the distance H1 between the galvanometer 60 and the micromirror 41 is L·tanα, where α is the angle between the prism assembly 110 and the galvanometer 60. When α is constant, H1 is proportional to L. In combination with the example in FIG. 5, the range of L is [a1, a2], where a2 is the diagonal of the profile of the galvanometer 60, and a1 is the side length of the profile of the galvanometer 60. In the related art, because the arrangement direction of the galvanometer 60 and the micromirror 41 is consistent, the distance H1 between the galvanometer 60 and the micromirror 41 is L·tanα=a2, so H1 is the largest at this time. In some embodiments, as shown in FIG. 7, L can be set to be smaller than a2, so H1 in some embodiments is smaller than H1 in FIG. 6. Therefore, the back focal length of the laser projection device can be shortened in some embodiments.

[0073] In the laser projection device provided in some embodiments of the present application, the galvanometer 60 is arranged between the light valve 40 and the projection lens 120. When the profile of the micromirror 41 and the projection of the prism assembly 110 on the light valve 40 are not parallel, the galvanometer 60 is arranged such that any side of the projection of the light valve 40 is not parallel to any side of the micromirror 41. In this way, the arrangement direction of the galvanometer 60 and the prism assembly 110 can be flexibly adjusted, the diagonal of the galvanometer 60 can be avoided from intersecting with the inclined surface of the prism assembly 110, the installation space of the galvanometer 60 on the inclined surface of the prism assembly 110 can be reduced, and the galvanometer 60 can be lowered to the side close to the light valve 40 during installation, so as to shorten the distance between the lens and the light valve 40.

[0074] In order to further reduce the back focal length of the lens, in some embodiments, the optical mirror 67 is parallel to the prism assembly 110 on one side of the projection of the light valve 40, that is, the arrangement direction of the optical mirror 67 is different from the arrangement direction of the micromirror 41 by 45°, so that one side of the optical mirror 67 is tangent to the inclined surface of the prism assembly 110, as shown in FIG. 9, and H1=L*tanα=a1, so that the distance between the galvanometer 60 and the light valve 40 is the shortest. In the fixed installation space, the original diagonal edge installation (the diagonal line of the galvanometer 60) is changed to the right angle edge installation, the right angle edge is shorter, the falling distance of the galvanometer 60 is greater, and the back focal length of the lens is shorter.

[0075] The principle of the galvanometer 60 realizing the beam deflection will be exemplarily introduced below.

[0076] In some embodiments, as shown in FIGS. 11a and 11b, the galvanometer 60 includes a circuit board 66 and an optical mirror 67 arranged on the circuit board 66. The circuit board 66 is configured to control the deflection of the optical mirror 67, and the optical mirror 67 is configured to control the beam deflection to the corresponding position point by the deflection of the optical mirror 67 itself. FIG. 10a is a schematic diagram of refraction of the optical mirror. As shown in FIG. 10a, in the deflection coordinate system, when the galvanometer 60 does not receive the current driving signal, the galvanometer 60 does not deflect, the incident light is vertically incident along the third axis Z, and the first deflection axis X and the second deflection axis Y (not shown, perpendicular to the plane where the first deflection axis X and the third axis Z are located) of the galvanometer 60 are both perpendicular to the input light. The outgoing light is directly emitted along the first deflection axis X and the second deflection axis Y. As shown in FIG. 10b, when the galvanometer 60 deflects clockwise by the first deflection angle θ1 with the second deflection axis Y as the rotation axis, the deflection distance of the outgoing light along the negative direction of the first deflection axis X is d1, which is the deflection distance of the pixel in the target image to be projected on the projection screen.

[0077] Based on the refraction law, it can be obtained that:

[0078] Wherein, t is the thickness of the optical glass 64 (see FIG. 12), and n is the refractive index of the optical glass 64. According to the above formula, the deflection distance d1 of the pixel is only related to the deflection angle θ of the galvanometer 60, the refractive index n of the optical glass 64, and the thickness t of the optical glass 64. After the galvanometer 60 is assembled, the refractive index n and the thickness t of the optical glass 64 are both fixed values, so the deflection distance d1 of the pixel mainly changes with the change of the deflection angle of the galvanometer 60. Therefore, by controlling the deflection angle of the galvanometer 60, the deflection distance of the pixel on the projection screen can be controlled.

[0079] In some embodiments, the optical mirror 67 and the circuit board 66 can be arranged in various manners. In some embodiments, as shown in FIG. 11a, the optical mirror 67, in the reset state, is parallel to one side of the projection of the circuit board 66 on the plane of the light valve. In some embodiments, the reset state of the optical mirror 67 refers to the state of the optical mirror 67 when it is not deflected.

[0080] In some embodiments, as shown in FIG. 11b, the optical mirror 67, in the reset state, is not parallel to any side of the projection of the circuit board 66 on the plane of the light valve. In some embodiments, the two are arranged at an angle of 45°. The outer contour of the circuit board 66 is the contour of the galvanometer 60. The deflection principle of the galvanometer 60 will be described below.

[0081] FIG. 12 is a structural schematic diagram of a galvanometer according to some embodiments. As shown in FIG. 12, the optical mirror 67 includes an optical glass 64 and a first magnetic component 62a and a second magnetic component 62b, the first magnetic component 62a and the second magnetic component 62b are arranged around the optical glass 64, and the first magnetic component 62a and the second magnetic component 62b form an angle of 90°. In some embodiments, the first magnetic component 62a is an electromagnet. Referring back to FIG. 12, the circuit board 66 includes a substrate 61, a first coil set 63a and a second coil set 63b, the first coil set 63a is arranged corresponding to the first magnetic component 62a, and the second coil set 63b is arranged corresponding to the second magnetic component 62b. In some embodiments, the first coil set 63a and the second coil set 63b can include coils.

[0082] In some embodiments, the current driving signal includes a first current driving signal for controlling the light beam to be offset along the direction of the first offset axis, and a second current driving signal for controlling the light beam to be offset along the direction of the second offset axis; the phase difference between the first current driving signal and the second current driving signal is a first angle. In combination with some of the above embodiments, and with reference to FIG. 12, the first coil group 63a can receive the first current driving signal, the first current driving signal provides currents in different directions, and generates magnetic forces in different directions to drive the first coil group 63a to move and further drive the optical mirror to rotate around the first deflection axis. Similarly, the second coil group 63b can receive the second current driving signal, and the working principle of the second coil group 63b is the same. In the process of projecting each frame of sub-image, the light valve 40 receives the irradiation of three primary color lights in a time sequence, and when the light valve 40 receives the irradiation of the target primary color light among the three primary color lights, the display control assembly can transmit the control signal of the galvanometer 60 corresponding to the frame image to the galvanometer driving assembly 600, and the control signal is used to control the galvanometer driving assembly 600 to provide the galvanometer current driving signal to the galvanometer 60 to drive the galvanometer 60 to deflect, and then the galvanometer 60 remains unchanged, thereby completing the display of one frame of image. Then, when displaying the next frame of image, the display control assembly and the galvanometer driving assembly 600 can drive the galvanometer 60 to deflect again, and the same is true for the subsequent frames, so as to realize the projection and display of different frames of images to different positions on the projection screen.

[0083] In some embodiments, assuming that the display resolution on the projection is 4K (3840x2160), and the corresponding resolution of the micromirror 41 on the light valve 40 is 1920x1080, in some embodiments, one period of the current driving signal includes four frames, and four position points are taken as an example for exemplary description of the offset process of one period, and the arrangement direction of the optical mirror and the circuit board is taken as an example (as shown in FIG. 11a). FIG. 13 is a timing diagram of the current driving signal in some embodiments. As shown in FIG. 13, the phase difference between the first current driving signal and the second current driving signal is 90°, and the first current driving signal and the second current driving signal include two signal values, i.e., the corresponding current values I1 and -I1. When the current value of the driving current changes, such as from positive to negative, or from negative to positive, it indicates that the direction of the driving current changes. In some embodiments, the arrangement direction of the galvanometer 60 and the micromirror 41 is different, and the arrangement direction difference is taken as an example of 45°. As shown in FIG. 14a, the position points of the pixel offset, a first coordinate system is established by the first deflection axis X and the third axis Z, a second coordinate system is established by the first deflection axis Y and the third axis Z, and a third coordinate system is established by the first offset axis and the second offset axis in the projection screen in FIG. 14(c). When the galvanometer 60 does not receive the current driving signal, the original position of the galvanometer 60 is O point.

[0084] In the t1 period of FIG. 13, the driving current (signal value) of the first current driving signal is I1, as shown in FIG. 14b, under the driving of the first current driving signal, the optical glass 64 rotates a first deflection angle θ1 along a first direction with the X axis as the rotation axis, under the driving of the second current driving signal with the driving current of -I1, the optical glass 64 rotates a first deflection angle θ1 along a third direction with the Y axis as the rotation axis, thereby the center point pixel in the first frame image A can be offset by a distance d1 in the negative direction of the X1 axis and a distance d1 in the negative direction of the Y1 axis, corresponding to the third coordinate system a.

[0085] In the t2 period of FIG. 13, the driving current of the first current driving signal is I1 and the driving current of the second current driving signal is I1, as shown in FIG. 14c, under the driving of the second current driving signal, the optical glass 64 rotates a second deflection angle θ2 (θ2 = 2θ1) along a fourth direction with the Y axis as the rotation axis, thereby the center point pixel in the second frame image B can remain unchanged in the X1 axis and be offset by a distance d2 (d2 = 2d1) in the negative direction of the Y1 axis, corresponding to the third coordinate system b.

[0086] In the t3 period of FIG. 13, the driving current of the first current driving signal is -I1 and the driving current of the second current driving signal is I1, as shown in FIG. 14d, under the driving of the first current driving signal, the optical glass 64 rotates a second deflection angle θ2 along a second direction with the X axis as the rotation axis, thereby the center point pixel in the third frame image C can be offset by d2 in the positive direction of the X1 axis and remain unchanged in the Y1 axis, corresponding to the third coordinate system c.

[0087] In the t4 period of FIG. 13, the driving current of the first current driving signal is -I1 and the driving current of the second current driving signal is -I1, as shown in FIG. 14e, under the driving of the second current driving signal, the optical glass 64 rotates a second deflection angle θ2 along a fifth direction with the Y axis as the rotation axis, thereby the center point pixel in the fourth frame image D can remain unchanged in the X1 axis and be offset by d2 in the negative direction of the Y1 axis, corresponding to the third coordinate system d. The current driving signal is a periodic signal, and each pixel point is periodically offset according to the above offset mode.

[0088] The above examples are illustratively described based on the current driving signal of FIG. 12 when the arrangement direction of the micromirror 41 and the galvanometer 60 is inconsistent. When the arrangement direction of the micromirror 41 and the galvanometer 60 is consistent, the principle is similar to the above when the current driving signal of FIG. 12 is driven, and the specific process is not described herein. The trajectory of the center point of each pixel point after offset is shown in FIG. 15.

[0089] It should be noted that, as shown in FIG. 3 and FIG. 4, there are gaps between the micro-mirrors 41 arranged in the light valve 40, and each micro-mirror 41 corresponds to a pixel, so there are also gaps between the pixels, which affect the display effect. For each frame, the more the shifted pixels cover the gaps of the previous frame, the better the display effect of the device. Conversely, the less the shifted pixels cover the gaps of the previous frame, the worse the display effect of the device. As shown in FIG. 14e, during the deflection process of the galvanometer 60 driven by the current driving signal in FIG. 13, the first trajectory where the position points of the pixels are located is inconsistent with the outline of the micro-mirror 41, and the gaps between the pixels are not completely covered. As shown in FIG. 15, when the arrangement direction of the micro-mirror 41 and the galvanometer 60 is consistent, the first trajectory where the position points of the pixels are located is consistent with the outline of the micro-mirror 41, and the gaps between the pixels are covered more. That is, when the arrangement direction of the micro-mirror 41 and the optical mirror 67 is consistent, the current driving signal as shown in FIG. 13 is applied, the gaps between the pixels are covered more, the display effect of the projection device is better, and the predetermined resolution can be achieved. When the arrangement direction of the micro-mirror 41 and the optical mirror 67 is inconsistent, the current driving signal as shown in FIG. 13 is applied, the gaps between the pixels are not completely covered, and the projection device cannot achieve the predetermined resolution.

[0090] Therefore, in some embodiments, FIG. 16 is a trajectory diagram of the position points of the pixels in some embodiments, as shown in FIG. 16, the galvanometer 60 is further configured to: for each frame, under the driving of the current driving signal, control the light beam to shift to the corresponding position point; the first trajectory formed by the corresponding position points of multiple frames is consistent with the outline of the micro-mirror 41, where "consistent" can be understood as the arrangement direction of the first trajectory is consistent with the arrangement direction of the micro-mirror 41, and the shape of the first trajectory is consistent with the outline of the micro-mirror 41. For the consistent arrangement direction, as shown in FIG. 16, one side of the first trajectory formed by the four position points is parallel to the micro-mirror 41. For the consistent shape, in some embodiments, if the outline of the micro-mirror 41 is rectangular, the first trajectory is also rectangular. For the shift distance, in some embodiments, the shift distance d1 of each shift is not longer than one-half of the diagonal of the micro-mirror 41 (pixel) and not shorter than one-half of the side length of the micro-mirror 41 (pixel), in combination with FIG. 5, the range of d1 is [a1 / 2, a2 / 2]. In some embodiments, d1=a2 / 2. In some embodiments, the first trajectory is consistent with the outline of the micro-mirror 41, and the shifted pixels of each frame can cover the gaps between the pixels, so the display effect can be improved according to the shift of the first trajectory in some embodiments.

[0091] In order to realize the first trajectory in the above-mentioned embodiments, the current driving signal needs to be controlled. The current driving signal will be exemplarily introduced below.

[0092] In some embodiments, FIG. 17 is a timing diagram of a current driving signal according to some embodiments of the present application. The current driving signal includes a first current driving signal for controlling the light beam to shift along a first shift axis and a second current driving signal for controlling the light beam to shift along a second shift axis. The phase difference between the first current driving signal and the second current driving signal is a first angle. In some embodiments, the first angle is 90°. In some embodiments, as shown in FIG. 17, each period of the first current driving signal corresponds to a first number of frames, and each frame corresponds to a position point in the first trajectory. The number of position points can be determined based on a ratio of a target resolution to a resolution corresponding to the micromirrors 41 in the light valve 40, such as the arrangement (pixels) 960x540 of the micromirrors 41 in the light valve 40, and the target resolution is 3840x2160, the first number is 8, so that one period includes 8 frames, corresponding to 8 position points; if the arrangement of the micromirrors 41 in the light valve 40 is 1920x1080, and the target resolution is 3840x2160, the first number is 4.

[0093] In some embodiments, continuing to refer to FIG. 17, the first current driving signal includes a plurality of driving data segments, each frame corresponding to a driving data segment, and each driving data segment corresponding to a signal value. The change in the signal value between two adjacent frames in the first current driving signal is used to control the shift between the corresponding position points of the light beam along the first shift axis. In some embodiments, the signal value can be the current value of the driving current. As can be seen from the example in FIG. 12, the greater the change in the current value between two adjacent frames, the greater the shift between the corresponding position points.

[0094] In some embodiments, when the projection of the optical mirror 67 on the plane of the light valve is parallel to one side of the projection of the circuit board 66 on the plane of the light valve in the reset state, the first current driving signal includes a second number of driving data segments with different signal values. The second number is half of the first number plus one. In the first current driving signal, the signal values of the driving data segments under adjacent frames are different.

[0095] It should be noted that in some embodiments, the projection of the prism assembly 110 on the light valve 40 is not parallel to any side of the micromirror 41. For example, the first number is 4, and the second number is 4 / 2+1=3, i.e., each period includes three current driving signal segments with different signal values, such as I1, I2, and I3, where I1>I2>I3.

[0096] In some embodiments, referring to FIG. 17, the signal values of the driving data segments in the first current driving signal are different in adjacent frames. In this case, the signal values of the current driving signal segments corresponding to the continuous frames in the same period change in order. The current driving signal in FIG. 13 includes two driving data segments with different signal values, and only one signal value of the driving data segment changes in the first current driving signal and the second current driving signal in each frame, i.e., the signal value in the first current driving signal changes or the signal value in the second current driving signal changes. In this way, the current driving signal can only be offset along one axis, and thus in the scenario where the arrangement directions of the micro mirror 41 and the galvanometer 60 are different, the pixel cannot be offset in the profile direction of the micro mirror 41. In some embodiments, compared with the current driving signal in FIG. 13, a driving data segment with a signal value is added, and in some embodiments, the signal values of the driving data segments corresponding to the first current driving signal and the second current driving signal in each frame change, so that the galvanometer 60 can be deflected on the first deflection axis X and the second deflection axis Y in each frame. In this way, the flexibility of control can be improved, and the first trajectory can be consistent with the profile of the micro mirror 41, thereby improving the display effect of the projection device.

[0097] In some embodiments, the first current driving signal includes a third number of driving data segments with different signal values, and the third number is half of the first number. For example, the first number is 4, and the second number is 4 / 2 = 2, i.e., each period includes two current driving signal segments with different signal values, such as I1 and -I1. For example, refer to the waveform diagram in FIG. 13.

[0098] Next, the first driving signal in the scenario where the projection of the optical mirror surface on the plane of the light valve on one side is parallel to the projection of the circuit board on the plane of the light valve on one side in the reset state is exemplarily described.

[0099] In some embodiments, the signal value is determined based on a first angle between a side of the projection of the galvanometer 60 on the optical mirror 67 and a side of the profile of the micro-mirror 41, and a first number. In some embodiments, the signal value represents a current value of the driving current. The greater the first angle, the greater the angle of deflection required, and the smaller the increase in the signal value of the corresponding consecutive frame if the first number is greater. In some embodiments, the second number of signal values are all greater than 0, or all less than 0. As shown in the timing diagram of the current driving signal in FIG. 18, in some embodiments, the current values are all greater than zero. In some embodiments, the second number of signal values are opposite to each other. As shown in FIG. 17, the signal values of the first current driving signal or the second current driving signal include I1, 0, I1. In some embodiments, the signal values of each current driving signal segment are symmetrical about the X axis, which reduces the computational difficulty of the control component in the process of generating the current driving signal, thereby reducing the requirements on the control component. In some embodiments, continuing to refer to FIG. 16, in the first current driving signal, the absolute values of the change amounts of the signal values of any two adjacent frames in the same period are the same.

[0100] For example, as shown in FIG. 17, the absolute value of the change amount of the signal value of the second frame relative to the first frame is I1, the absolute value of the change amount of the signal value of the third frame relative to the first frame, and the absolute value of the change amount of the signal value of the fourth frame relative to the third frame are also I1. When the change amounts of the signal values of each frame are the same, the pixel shift distances are also equal, that is, the pixels of each frame are uniformly moved in some embodiments. Through the arrangement of some embodiments, the pixels can be uniformly shifted by the same distance, so that the pixels do not jump, thereby improving the display effect.

[0101] In some embodiments, FIG. 19 is a timing diagram of another current driving signal provided by some embodiments of the present application. As shown in FIG. 19, in the first current driving signal, the absolute values of the change amounts of the signal values of adjacent two frames in the same period are not completely the same. For example, as shown in FIG. 19, the absolute value of the change amount of the signal value of the second frame relative to the first frame is I1, the absolute value of the change amount of the signal value of the third frame relative to the second frame is I2, and the absolute value of the change amount of the signal value of the fourth frame relative to the third frame is I1, wherein I1 and I2 are not equal. In this way, the deflection angles of the galvanometer 60 in different frames can be different, and thus the flexibility of pixel shift can be improved in some embodiments. It is worth mentioning that the second current driving signal is a signal with the same frequency and amplitude as the first current driving signal, and the phase difference is a first angle. Therefore, the second current driving signal has a similar structure to the first current driving signal in the above embodiments, and specific details can be referred to the above examples, which will not be described here.

[0102] The process of realizing that the first trajectory is consistent with the profile of the micro-mirror 41 based on the current driving signal will be described below.

[0103] For example, the current driving signals in FIG. 17 are taken as an example, as shown in FIG. 17, the first quantity is 4, the phase difference between the first current driving signal and the second current driving signal is 90°, and the first current driving signal and the second current driving signal each include three signal values, i.e. corresponding current values. As shown in FIG. 11a, when the galvanometer 60 does not receive the current driving signal, the original position corresponding to the galvanometer 60 is point O.

[0104] In some embodiments, the arrangement direction of the optical mirror 67 is inconsistent with the arrangement direction of the micro mirror 41, for example, the arrangement direction is 45° different. As shown in FIG. 20a, a first coordinate system is established with the first deflection axis X and the third axis Z, a second coordinate system is established with the second deflection axis Y and the third axis Z, and a third coordinate system is established in the projection screen with the first deflection axis X1 and the second deflection axis Y1.

[0105] In some embodiments, in the first current driving signal, when the signal value change amount of the current driving signal segment of the adjacent two frames is a negative value, the optical mirror 67 deflects clockwise around the first deflection axis X, corresponding to the first direction F1. When the signal value change amount is a positive value, the galvanometer 60 deflects counterclockwise around the first deflection axis X, corresponding to the second direction F2. In the second current driving signal, when the signal value change amount of the current driving signal segment of the adjacent two frames is a negative value, the optical mirror 67 deflects clockwise around the second deflection axis Y, corresponding to the third direction F3. When the signal value change amount is a positive value, the optical mirror 67 deflects counterclockwise around the second deflection axis Y, corresponding to the fourth direction F4.

[0106] In the t1 period of FIG. 17, the driving current (signal value) of the first current driving signal is -I1, and the driving current of the second current driving signal is 0. Under the driving of the first current driving signal, as shown in FIG. 20a, the optical glass 64 rotates a third deflection angle θ3 along the first direction F1 with the X axis as the rotation axis, thereby realizing that the center point pixel in the first frame image A is offset by a distance d1 in the negative direction of the X1 axis and remains unchanged in the Y1 axis, corresponding to the third coordinate system a.

[0107] In the t2 period of FIG. 17, the driving current of the first current driving signal is 0, and the driving current of the second current driving signal is I1. As shown in FIG. 20b, under the driving of the first current driving signal, the optical glass 64 rotates a fourth deflection angle θ4 along the second direction F2 with the X axis as the rotation axis, and under the driving of the second current driving signal, the optical glass 64 rotates the fourth deflection angle θ4 along the fourth direction F4 with the Y axis as the rotation axis, thereby realizing that the center point pixel in the second frame image B is offset by d2 in the positive direction of the X1 axis and by d2 in the positive direction of the Y1 axis, corresponding to the third coordinate system b.

[0108] In the t3 period of FIG. 17, the driving current of the first current driving signal is I1, and the driving current of the second current driving signal is 0. As shown in FIG. 20c, under the driving of the first current driving signal, the optical glass 64 rotates by a fourth deflection angle 2xθ4 in the second direction F2 with the X axis as the rotation axis, and under the driving of the second current driving signal, the optical glass 64 rotates by the fourth deflection angle θ4 in the third direction F3 with the Y axis as the rotation axis, thereby realizing that the center point pixel of the third frame image C is offset by 2d2 in the positive direction of the X1 axis and by a distance d2 in the positive direction of the Y1 axis, corresponding to the third coordinate system c.

[0109] In the t4 period of FIG. 17, the driving current of the first current driving signal is 0, and the driving current of the second current driving signal is -I1. As shown in FIG. 20d, under the driving of the first current driving signal, the optical glass 64 rotates by the fourth deflection angle θ4 in the first direction, and under the driving of the second current driving signal, the optical glass 64 rotates by twice the fourth deflection angle 2θ2 in the third direction F3 with the Y axis as the rotation axis, thereby realizing that the center point pixel of the fourth frame image D is offset by d2 in the negative direction of the X1 axis and by 2d2 in the positive direction of the Y1 axis, corresponding to the third coordinate system d. The current driving signal is a periodic signal, and each pixel point is periodically offset according to the above offset mode.

[0110] As can be seen from the above embodiments, the current driving signal provided by some embodiments of the present application can realize that the first trajectory formed by the position points of the pixel offset is consistent with the outline of the micromirror 41 (pixel), and can further cover the gap between each pixel, thereby improving the display effect of the device. The above only shows some embodiments in which one period includes four position points, but in some embodiments, the first number is not limited to the above four, and may, for example, be eight or 4n, or six.

[0111] In some embodiments, FIG. 21 is a timing diagram of the current driving signal in an example in which the first number is eight. As shown in FIG. 21, as shown in FIG. 21 (I), the first current driving signal includes five driving data segments with different signal values, which are I2, I1, 0, -I1, and -I2, respectively. The first trajectory of the corresponding position points is shown in FIG. 21 (II). In some embodiments, the first number may, for example, be six or another number.

[0112] For the first driving signal (FIG. 13) in the scenario in which the projection of the optical mirror surface in the plane where the light valve is located is not parallel to any side of the projection of the circuit board in the plane where the light valve is located and is parallel to one side of the outline of the light valve, the control process of one period is similar to the above, which will not be described here.

[0113] In some embodiments, the galvanometer 60 further comprises at least one elastic member connected with the substrate 61 and the optical glass 64 for mounting the optical glass 64. For example, the elastic member can be a spring. The elastic member reciprocates under the electromagnetic force, and the driving current of the optical glass 64 is constant (signal value) in the constant stage, and the positioning needs to be stable to make the projection lens 120 display stable images. However, the elastic member will reciprocate simple harmonic vibration when the driving current changes suddenly, which will affect the positioning accuracy. Therefore, in some embodiments, the first current driving signal further comprises a plurality of first signal segments; the first signal segment is arranged between the current driving signal segments corresponding to adjacent frames, and the first signal segment is used to stabilize the deflection position of the light beam.

[0114] Further, FIG. 22 is a timing diagram of a current driving signal according to some embodiments. As shown in FIG. 22, the first signal segment can be a 1.5-period sine wave. In some embodiments, the first signal segment is used to compensate for the simple harmonic motion of the elastic member, so that the optical glass 64 can be stabilized in the stable stage of the driving current. In the above-mentioned embodiments in which the galvanometer 60 comprises the first coil group 63a and the second coil group 63b, as shown in FIG. 12, the first coil group 63a receives the first current driving signal, and is used to control the deflection of the optical glass 64 around the first deflection axis by the first magnetic assembly 62a under the driving of the first current driving signal, so as to control the deflection of the light beam along the first deflection axis; and the second coil group 63b receives the second current driving signal, and is used to control the deflection of the optical glass 64 around the second deflection axis by the second magnetic assembly 62b under the driving of the second current driving signal, so as to control the deflection of the light beam along the second deflection axis.

[0115] In some embodiments, the first coil group 63a can only comprise one first coil. Then, some embodiments only use one first coil to control the deflection of the optical glass 64 around the first deflection axis. Setting one coil can simplify the structure of the circuit board. In some embodiments, the first coil group 63a can comprise a first coil and a second coil. The first coil and the second coil can be arranged at the same end of the optical glass 64, or can be arranged at opposite ends of the optical glass 64. In the embodiments in which the first coil and the second coil are arranged at opposite ends of the optical glass 64, the first coil and the second coil can be connected in series, as shown in FIG. 12. In this way, the first coil and the second coil can receive one first current driving signal. In this way, the number of input signals can be reduced. In some embodiments, the first coil and the second coil are arranged at opposite ends of the optical glass 64, and the first coil and the second coil are not connected, and the first coil and the second coil respectively receive the first current driving signal, i.e., the first coil group 63a receives two first current driving signals.

[0116] In some embodiments, the first coil and the second coil are arranged in the same direction, and the first current drive signals of the first coil and the second coil are opposite signals. When arranged in the same direction, if the first current drive signals are the same, the magnetic fields generated by the first coil and the second coil are in the same direction, and the rotation of the optical mirror cannot be achieved. Therefore, in this scenario, the flipping of the optical mirror is achieved by setting opposite first current drive signals. In some embodiments, the first coil and the second coil are arranged in opposite directions, and the first current drive signals of the first coil and the second coil are opposite signals. Similarly, when arranged in opposite directions, if the first current drive signals are the same, the magnetic fields generated by the first coil and the second coil are in opposite directions. Therefore, in this scenario, the flipping of the optical mirror is achieved by setting opposite first current drive signals.

[0117] Finally, it should be noted that: the above some embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing some embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing some embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0118] For the convenience of explanation, the above description has been made in combination with specific embodiments. However, the above exemplary discussion is not intended to exhaust or limit the embodiments to the specific forms disclosed above. Various modifications and variations can be derived according to the above teachings. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different modified embodiments suitable for specific use considerations.

Claims

1. A laser projection device, comprising: The light source is configured to emit tri-color light beams; An optical valve comprising a plurality of arrayed micromirrors configured to modulate and output the tri-color beam; A prism assembly, located between the light valve and the projection lens, is configured to guide the light beam emitted by the light source into the light valve and to guide the light modulated by the light valve toward the projection lens; A galvanometer, including an optical mirror, is located between the optical valve and the projection lens. Either side of the projection of the optical mirror onto the plane of the optical valve is not parallel to either side of the micromirror. The galvanometer is configured to change the position of the light beam output by the optical valve at different times under the control of a current-driven signal. The projection lens is configured to perform imaging based on the light beam output by the galvanometer at different times.

2. The laser projection device according to claim 1, wherein, The projection of the prism assembly onto the plane of the light valve is not parallel to either side of the micromirror.

3. The laser projection device according to claim 1, wherein, One side of the projection of the optical mirror onto the plane where the light valve is located is parallel to one side of the projection of the prism assembly onto the plane where the light valve is located.

4. The laser projection device according to claim 1, wherein, The galvanometer is also configured to: For each frame, the beam is controlled to deflect to the corresponding position point under the drive of the current driving signal; the first trajectory formed by the position points corresponding to multiple frames is consistent with the contour of the micromirror.

5. The laser projection device according to claim 4, wherein, The current driving signal includes a first current driving signal that controls the beam to deflect along the first offset axis direction, and a second current driving signal that controls the beam to deflect along the second offset axis direction. The phase difference between the first current drive signal and the second current drive signal is a first angle.

6. The laser projection device according to claim 5, wherein, Each cycle of the first current driving signal corresponds to a first number of frames, and each frame corresponds to a position point in the first trajectory. The first current driving signal includes multiple driving data segments, with each frame corresponding to one driving data segment and each driving data segment corresponding to one signal value. The change in the signal value between two adjacent frames in the first current driving signal is used to control the offset between the position points corresponding to the beam on the first offset axis.

7. The laser projection device according to claim 6, wherein, The first current drive signal includes a second number of drive data segments with different signal values; the second number is half of the first number plus one. In the first current drive signal, the signal values ​​of the drive data segments in adjacent frames are different.

8. The laser projection device according to claim 7, wherein, The signal value is determined based on a first angle between one side of the projection of the galvanometer onto the optical valve and the side corresponding to the contour of the micromirror, and the first quantity.

9. The laser projection device according to claim 7, wherein, In the first current-driven signal, the absolute value of the change in signal value between any two adjacent frames in the same period is the same.

10. The laser projection device according to claim 7, wherein, In the first current-driven signal, the absolute values ​​of the changes in signal values ​​between two adjacent frames in the same period are not exactly the same.

11. The laser projection device according to claim 7, wherein, In each cycle of the first current drive signal, a first number of signal values ​​are opposites of each other.

12. The laser projection device according to claim 7, wherein, The first current drive signal also includes multiple first signal segments. The first signal segment is positioned between current-driven signal segments corresponding to adjacent frames, and the first signal segment is used to stabilize the deflection position of the beam.

13. The laser projection device according to claim 7, wherein, The first signal segment is a sine wave with 1.5 cycles.

14. The laser projection device according to claim 1, wherein, The galvanometer also includes a circuit board, and the optical mirror is disposed on the circuit board. The circuit board is configured to drive the optical mirror to deflect based on the current driving signal, and the optical mirror is configured to control the beam to deflect to the corresponding position point through its own deflection.

15. The laser projection device according to claim 14, wherein, When the optical mirror is in the reset state, and one side of the projection of the optical valve onto the plane is parallel to one side of the projection of the circuit board onto the plane of the optical valve, the first current driving signal includes a second number of driving data segments with different signal values; the second number is half of the first number plus one; in the first current driving signal, the signal values ​​of the driving data segments in adjacent frames are different.

16. The laser projection device according to claim 1, wherein, The angle formed by one side of the projection of the prism assembly onto the plane of the light valve and one side of the contour of the micromirror is neither zero nor 90 degrees.

17. The laser projection device according to claim 4, wherein, The first trajectory is a rectangular trajectory.

18. The laser projection device according to claim 1, wherein, One side of the projection of the optical mirror onto the plane where the light valve is located is parallel to one side of the projection of the prism assembly onto the plane where the light valve is located, and the first trajectory formed by the position points corresponding to multiple frames is consistent with the contour of the micromirror.

19. A laser projection device, comprising: The light source is configured to emit tri-color light beams; An optical valve comprising a plurality of arrayed micromirrors configured to modulate and output the tri-color beam; A prism assembly, located between the light valve and the projection lens, is configured to guide a light beam emitted from the light source into the light valve and to guide the light modulated from the light valve toward the projection lens; A galvanometer, located between the light valve and the projection lens, comprises: Circuit boards; and An optical mirror is mounted on the circuit board. Wherein, the projection of any side of the optical mirror onto the plane where the light valve is located is not parallel to the projection of any side of the circuit board onto the plane where the light valve is located; the galvanometer is configured to change the position of the light beam output by the light valve at different times through the optical mirror under the control of the current driving signal. The projection lens is configured to perform imaging based on the light beam output by the galvanometer at different times.

20. The laser projection device according to claim 19, wherein, The projection of one side of the optical mirror onto the plane of the light valve forms an angle of approximately 45 degrees with the projection of one side of the circuit board onto the plane of the light valve.

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