Projection apparatus

Abstract

A projection apparatus, comprising: a light modulation assembly (10), a dimming film (40), a transflective mirror (20), and a reflective mirror (30). The dimming film (40) is arranged on the light exit side of the light modulation assembly (10), and the transflective mirror (20) is arranged on the side of the dimming film (40) distant from the light modulation assembly (10); when a plurality of first light rays (L1) emitted from the light modulation assembly (10) pass through the dimming film (40), a plurality of corresponding second light rays (L2) are formed and emitted to the transflective mirror (20), and at least some of the second light rays (L2) are reflected by the transflective mirror (20) to the reflective mirror (30) and are then reflected by the reflective mirror (30) to the transflective mirror (20) to be emitted; among the plurality of first light rays (L1), the first light rays (L1) of which the divergence angles are greater than a first preset value are target light rays, and the divergence angles of second light rays (L2) corresponding to at least some of the target light rays are less than the divergence angles of the target light rays.

Description

Projection device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a projection device. Background Art

[0002] Telescopic screen products are used to prevent myopia. In telescopic screen products, the light from the display screen is reflected into the human eye and forms a distant virtual image with a viewing distance of 5 to 12 meters, thereby adjusting the retinal imaging distance position and achieving the effect of myopia prevention and control. Summary of the Invention

[0003] The present disclosure provides a projection device capable of reducing stray light generated during an imaging process.

[0004] The present disclosure provides a projection device, comprising: a light modulation component, a dimming film, a transflective mirror, and a reflective mirror; the dimming film is arranged on the light-emitting side of the light modulation component, and the transflective mirror is arranged on the side of the dimming film away from the light modulation component;

[0005] After passing through the dimming film, the plurality of first light rays emitted by the light modulation component form corresponding plurality of second light rays that are emitted toward the transflective mirror, and at least a portion of the second light rays are reflected by the transflective mirror toward the reflective mirror, and then reflected by the reflective mirror to be emitted from the transflective mirror;

[0006] Among the multiple first light rays, the first light rays with a divergence angle greater than a first preset value are target light rays, and the divergence angle of the second light rays corresponding to at least some of the target light rays is smaller than the divergence angle of the target light rays.

[0007] In some embodiments, the extended surface of the reflective mirror intersects with the extended surface of the light modulation component at a first intersection line; wherein, a portion of the multiple target light rays emitted by the light modulation component is a first target light ray, the orthographic projection of the first target light ray on the light modulation component is perpendicular to the first intersection line, and the divergence angle of the first target light ray is greater than a second preset value, and the second preset value is greater than the first preset value; the divergence angle of the second light ray corresponding to the first target light ray is less than or equal to the second preset value.

[0008] In some embodiments, the projection device further includes a lens, which is disposed between the dimming film and the transflective mirror. One of the surface shapes of the lens and the reflective mirror is convex, and the other is concave.

[0009] In some embodiments, at least a portion of the light emitted from the lens is reflected by the reflective mirror to the reflector, wherein, for multiple light rays emitted from the lens to the reflector, there is a first distance between the exit position of the light on the lens and the central axis of the lens, and there is a second distance between the incident position of the light path on the reflector and the central axis of the reflector, and the first distance is positively correlated with the second distance.

[0010] In some embodiments, the reflective surface of the reflector is a concave surface, and the lens is a convex lens.

[0011] In some embodiments, a surface of the lens facing the light modulation component is a plane, and a surface of the lens facing away from the light modulation component is a convex surface.

[0012] In some embodiments, the reflective surface of the reflector is mirror-symmetrical about a first reference plane and a second reference line, the first reference plane is a plane passing through the center of the reflective surface and parallel to the light modulation component, and the second reference plane is a plane passing through the central axis of the reflective surface and perpendicular to the first reference plane.

[0013] In some embodiments, a central axis of the lens intersects the transflective mirror at a first intersection point, and a central axis of the reflective mirror intersects the first intersection point.

[0014] In some embodiments, there is a third distance between the first intersection point and the center of the reflector, and a fourth distance between the center of the surface of the lens facing the transflective mirror and the first intersection point, and the fourth distance is greater than the third distance.

[0015] In some embodiments, an anti-reflection film is provided on at least the surface of the lens facing away from the light modulation component.

[0016] In some embodiments, the light emitting area of ​​the light modulation component is rectangular, a first light-shielding layer in a ring shape is provided on the lens, the inner edge of the ring shape is rectangular, and the length of the inner edge of the ring shape is 2*(tanθ*h+L / 2), and the width of the inner edge of the ring shape is 2*(tanθ*h+W / 2), wherein 75°≤θ≤85°, L is the length of the display area, W is the width of the display area, and h is the distance between the light modulation component and the lens.

[0017] In some embodiments, the lens is a solid lens, or a liquid lens.

[0018] In some embodiments, the projection device further comprises:

[0019] A first quarter wave plate is arranged on a side of the dimming film away from the light modulation component;

[0020] A second quarter-wave plate is arranged on a side of the transflective mirror away from the light modulation component;

[0021] The polarizer is arranged on a side of the second quarter-wave plate away from the transflective mirror.

[0022] In some embodiments, the polarizer and the second quarter-wave plate both cover at least the effective area of ​​the transflective mirror, the light-emitting area of ​​the light modulation assembly is rectangular, the effective area is an isosceles trapezoid, the short side and the long side of the isosceles trapezoid are parallel to the long side of the light-emitting area, the length of the long side of the isosceles trapezoid is: L*m, the length of the short side of the isosceles trapezoid is: L*m*cosA, and the waist length of the isosceles trapezoid is: W*m*cosA;

[0023] Wherein, L is the length of the light emitting area of ​​the light modulation component, W is the width of the light emitting area, A is the angle between the extension surface of the transflective mirror and the extension surface of the light modulation component, and m is the magnification of the reflector.

[0024] In some embodiments, the projection device further includes: a half-wave plate, which is arranged between the first quarter-wave plate and the dimming film, and the orthographic projection of the half-wave plate on the light modulation component covers the orthographic projection of the first quarter-wave plate on the light modulation component.

[0025] In some embodiments, the transflective mirror includes an effective area and an ineffective area surrounding the effective area, and the effective area is an area on the transflective mirror illuminated by the reflected light of the reflector;

[0026] Wherein, a second light-shielding layer is provided on the surface of the transflective mirror facing away from the reflective mirror, and the second light-shielding layer covers at least a portion of the ineffective area.

[0027] In some embodiments, the inactive region includes a first inactive region located on a side of the active region close to the light modulation component, and the second light shielding layer at least covers the first inactive region. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0029] FIG1 is a schematic diagram of a projection device provided in one example.

[0030] FIG2 is a perspective view of a projection device provided in some embodiments of the present disclosure.

[0031] FIG3 is a cross-sectional view of a projection device provided in some embodiments of the present disclosure.

[0032] FIG4 is a perspective view of a projection device provided in some other embodiments of the present disclosure.

[0033] FIG5 is a cross-sectional view of a projection device provided in some other embodiments of the present disclosure.

[0034] FIG6 is an exploded view of a projection device provided in some other embodiments of the present disclosure.

[0035] FIG7 is a cross-sectional view along the short side of the light modulation element.

[0036] FIG8 is a schematic diagram of irradiance simulation of the projection device provided in the embodiment of the present disclosure and the projection device of the comparative example.

[0037] FIG9 is a schematic diagram showing the shapes of images when the reflecting surfaces are respectively a flat surface and a concave surface.

[0038] FIG10 is a schematic diagram of relevant dimensions of a projection device provided in some embodiments of the present disclosure.

[0039] FIG11 is a diagram showing the angular distribution of light emitted from a lens provided in some embodiments of the present disclosure.

[0040] FIG12 is a plan view of a lens and a first light-shielding layer provided in some embodiments of the present disclosure.

[0041] FIG13 is a schematic diagram of a liquid lens provided in some embodiments of the present disclosure.

[0042] FIG14 is a schematic diagram of a projection device provided in some further embodiments of the present disclosure.

[0043] FIG15 is a schematic diagram of an effective area on a transflective mirror provided in some embodiments of the present disclosure.

[0044] FIG. 16 is an MTF diagram of a projection device provided in an example of the present disclosure.

[0045] FIG. 17 is a point diagram of a projection device provided in one example of the present disclosure.

[0046] FIG18 is a field curvature diagram and a distortion diagram of a projection device provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0047] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0048] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0049] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should have the usual meanings understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0050] As used herein, "parallel" and "perpendicular" include the conditions described and conditions similar to the conditions described, and the range of the similar conditions is within an acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range for approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range for approximate perpendicularity can also be, for example, a deviation within 5°.

[0051] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0052] Exemplary embodiments are described herein with reference to cross-sectional and / or plan views that are idealized exemplary drawings. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0053] In the telescopic screen product, the light from the display screen is reflected into the human eye and forms a distant virtual image with a viewing distance of 5 to 12 meters, thereby adjusting the retinal imaging distance position and achieving the effect of myopia prevention and control.

[0054] Figure 1 is a schematic diagram of a projection device provided in one example, which can be used as a telescopic screen product. As shown in Figure 1 , a light modulation assembly 10 is used to provide image light. For example, light modulation assembly 10 is a display panel, which can be a liquid crystal display panel. The image light from light modulation assembly 10 is directed to a transflective mirror 20. Transflective mirror 20 transmits a portion of the received image light to a reflector 30. The light is reflected by reflector 30 back to transflective mirror 20 and then emitted through transflective mirror 20 toward an eyebox area 90. When an observer's eyes are within eyebox area 90, they receive the light output by the projection device and can see a virtual image 91 in the opposite direction of the light. Specifically, eyebox area 90 refers to the area where the observer's eyes are located and where the image output by the projection device can be seen. Eyebox area 90 has a certain size. Even if the observer's eyes are offset by a certain distance from the center of eyebox area 90, such as in the vertical or horizontal direction, as long as they remain within eyebox area 90, they can still see the image output by the projection device.

[0055] The inventors discovered that the high-angle light L11 emitted by the light modulation assembly 10 passes through the transflective mirror 20 and directly reaches the eyebox area 90. These rays do not follow the normal reflection path (i.e., they are not reflected by the reflective mirror). In other words, these rays are equivalent to stray light. However, the low-angle light L12 emitted by the light modulation assembly 10, even if these rays directly pass through the transflective mirror 20, do not reach the eyebox area 90, thus not affecting the viewer's viewing experience.

[0056] Figure 2 is a stereoscopic view of a projection device provided in some embodiments of the present disclosure, Figure 3 is a cross-sectional view of a projection device provided in some embodiments of the present disclosure, Figure 4 is a stereoscopic view of a projection device provided in other embodiments of the present disclosure, Figure 5 is a cross-sectional view of a projection device provided in other embodiments of the present disclosure, and Figure 6 is an exploded view of a projection device provided in other embodiments of the present disclosure. As shown in Figures 2 to 6, the projection device includes: a light modulation component 10, a transflective mirror 20, a reflective mirror 30 and a dimming film 40.

[0057] Optionally, the light modulation component 10 may be a display panel, such as a liquid crystal display panel. The transflective mirror 20 is disposed on the light-emitting side of the light modulation component 10. The transflective mirror 20 is an element having a certain transmittance and a certain reflectance, and is used to transmit a portion of the received light and reflect the other portion. For example, the transflective mirror 20 may transmit 50% of the light and reflect 50% of the light. For another example, the transflective mirror 20 may transmit 60% of the light and reflect 40% of the light. For another example, the transflective mirror 20 may transmit 40% of the light and reflect 60% of the light. The transflective mirror 20 may specifically include a transparent substrate (e.g., a glass substrate) and a transflective film disposed on the transparent substrate.

[0058] The dimming film 40 is disposed on the light-emitting side of the optical modulation component 10, between the optical modulation component 10 and the transflective mirror 20. That is, the light emitted by the optical modulation component 10 passes through the dimming film 40 and is directed toward the transflective mirror 20. The dimming film 40 is used to adjust the angle of at least a portion of the light. Specifically, after passing through the dimming film 40, the multiple first light rays L1 emitted by the optical modulation component 10 are converted into corresponding multiple second light rays L2 that are directed toward the transflective mirror 20, with each first light ray L1 corresponding to a second light ray L2. Among the multiple first light rays L1, the first light rays L1 having a divergence angle greater than a first preset value are designated as target light rays, and the divergence angle of the second light rays L2 corresponding to at least a portion of the target light rays is smaller than the divergence angle of the target light rays. In other words, the divergence angle of at least a portion of the high-angle first light rays L1 decreases after passing through the dimming film 40.

[0059] It should be noted that the divergence angle of the light is the angle between the emission direction of the light and the central axis of the light modulation component 10 .

[0060] The transflective mirror 20 is disposed on the side of the dimming film 40 away from the light modulator 10. Of the multiple second light rays L2 directed toward the transflective mirror 20, at least a portion of the second light rays L2 are reflected by the transflective mirror 20 toward the reflector 30. From there, they are reflected back to the transflective mirror 20 and emitted toward the eyebox area for viewing by the observer. It should be noted that the figures of this disclosure merely schematically illustrate the relative positional relationships between the various components and do not strictly indicate the size of the gaps between them. For example, in the cross-sectional views of the projection devices, a gap is depicted between the transflective mirror 20 and the light modulator 10 to clearly illustrate the light changes. In reality, there may not be a gap between the two, and the transflective mirror 20 may be attached to the light-emitting surface of the light modulator 10. In this case, the first light ray L1 can be considered to be the light emitted by the light modulator 10 when the transflective mirror 20 is not provided.

[0061] As analyzed above, the large-angle light emitted by the light modulation component 10 acts as stray light and affects the viewing experience. In the embodiment of the present disclosure, by setting the dimming film 40, the divergence angle of at least part of the large-angle light emitted by the light modulation component 10 can be reduced, thereby reducing the stray light of the projection device during the imaging process and improving the observer's viewing experience.

[0062] In some embodiments, the extended surface of the transflective mirror 20 intersects the extended surface of the light modulation assembly 10 at a first intersection line. As shown in FIG6 , the projection device may further include a housing 80, comprising a first sidewall 81 and a second sidewall 82 disposed opposite each other, both of which are perpendicular to the first intersection line. The transflective mirror 20 and the light modulation assembly 10 are disposed between the first sidewall 81 and the second sidewall 82. In this case, if the orthographic projection of a large-angle first light ray L1 on the light modulation assembly 10 is parallel to the first intersection line, then, even without adjusting the angle of the first light ray L1, the first light ray L1 will still be emitted toward the first sidewall 81 and the second sidewall 82, thereby being absorbed by the housing 80 and not emitting stray light to the human eye. Therefore, in the disclosed embodiment, the dimming film 40 only needs to adjust a portion of the target light emitted by the light modulation assembly 10.

[0063] For example, a portion of the multiple target light rays emitted by the optical modulation component 10 are first target light rays, whose orthographic projections on the optical modulation component 10 are perpendicular to the first intersection line, and whose divergence angles are greater than a second preset value, which is greater than the first preset value. The divergence angles of the second light rays L2 corresponding to the first target light rays are less than the second preset value. That is, after being adjusted by the dimming film 40, the divergence angles of the first light rays L1, whose divergence angles are greater than the second preset value and whose orthographic projections are perpendicular to the first intersection line, are less than their divergence angles before adjustment. Furthermore, a portion of the multiple first light rays L1 are second target light rays, whose orthographic projections on the optical modulation component 10 are parallel to the first intersection line. The dimming film 40 may not adjust the angles of the second target light rays. That is, the divergence angles of the second light rays L2 corresponding to the second target light rays are equal to the divergence angles of the second target light rays.

[0064] For example, the dimming film 40 is a grid structure, which includes multiple bars, the extension direction of each bar is parallel to the first intersection line, and the arrangement direction of the multiple bars is perpendicular to the first intersection line, so that the angle of the first target light can be adjusted without adjusting the angle of the second target light.

[0065] In one example, the first preset value is between 3° and 10°, and the second preset value is between 15° and 60°. For example, the first preset value is 5°, and the second preset value is between 15° and 40°, or between 40° and 60°. In a specific example, the second preset value is 50°, that is, after the multiple first target light rays pass through the dimming film 40, the divergence angles of most or all of the multiple second light rays formed are less than 50°. For example, through the specific structural setting of the dimming film 40, after more than 93% of the first target light rays pass through the dimming film 40, the divergence angle of the emitted light does not exceed 50°.

[0066] In one example, among the multiple second light rays L2 emitted by the dimming film 40, the divergence angle of the second light ray L2 corresponding to the first target light ray is no greater than 25°, and the divergence angle of the second light ray L2 corresponding to the second target light ray is no greater than 90°. Figure 7 is a cross-sectional view along the short side of the light modulation component 10. Taking the light modulation component 10 as an example, where the long side of the long side is parallel to the first intersection line, the divergence angle γ of the light emitted by the dimming film 40 along the short side of the light modulation component 10 is no greater than 25°; and the divergence angle of the light emitted by the dimming film 40 along the long side of the light modulation component 10 is no greater than 90°.

[0067] FIG8 is a schematic diagram of irradiance simulation of a projection device provided in an embodiment of the present disclosure and a projection device of a comparative example, wherein the projection device of the comparative example adopts the structure shown in FIG1 , and the projection device of the present disclosure adopts the structure shown in FIG14 . FIG14 adds a dimming film 40 to FIG1 , and in the long side direction of the light modulation component 10, the dimming film 40 does not change the angle of the light; in the short side direction of the light modulation component 10, the dimming film 40 adjusts the light beam angle to within 50°, that is, the angle between the exit direction of the light and the central axis of the dimming film 40 is within 25°. In FIG8 , "BOE" is the pattern to be displayed, and the pattern with the same color as "BOE" in the area below "BOE" is a stray image. As can be seen from FIG8 , in the embodiment of the present disclosure, the provision of the dimming film 40 can reduce the generation of stray images.

[0068] In some embodiments, as shown in Figures 4 to 6, the reflective surface of the reflector 30 is a curved surface. The projection device further includes a lens 50, which is disposed between the dimming film 40 and the transflective mirror 20. One of the surface shapes of the lens 50 and the reflector 30 is convex, and the other is concave. After the second light L2 is emitted toward the lens 50, it is adjusted by the lens 50 and then emitted toward the transflective mirror 20. At least a portion of the light emitted from the lens 50 is reflected by the transflective mirror 20 toward the reflector 30. Furthermore, for the plurality of light rays emitted from the lens 50 toward the reflector 30, a first distance exists between the exit position of the light on the lens 50 and the central axis of the lens 50, and a second distance exists between the incident position of the light path on the reflector 30 and the central axis of the reflector 30. The first distance and the second distance are positively correlated. That is to say, the closer the light is to the center of the lens 50 , the closer its incident position on the reflector 30 is to the center of the reflector 30 ; the farther the light is from the center of the lens 50 , the farther its incident position on the reflector 30 is from the center of the reflector 30 .

[0069] In one example, the reflective surface of the reflector 30 is concave, that is, the reflective surface of the reflector 30 is curved in a direction away from the transflector 20; accordingly, the lens 50 is a convex lens. When the reflective surface is concave, after the light reflected by the reflective surface enters the human eye, the observer can see a magnified virtual image on the side of the reflector 30 away from the transflector 20, in the opposite direction of the light path. However, since the reflective surface is concave, the optical path of the light at the edge of the display panel is large, and the optical path of the light at the center is small. It can also be seen that the concave reflective surface causes the light at the edge to be dense and the light at the center to be sparse, thus causing the image seen by the human eye to be distorted. Figure 9 is a schematic diagram of the shape of the image when the reflective surface is a plane and a concave surface, respectively. When the reflective surface is a plane, the virtual image 91 seen by the human eye is a rectangle; when the reflective surface is concave, the virtual image 91' seen is no longer a rectangle, but has a shape with four convex arcs on all sides. In the embodiment of the present disclosure, by providing a convex lens, the optical path of the central light of the display panel can be increased, and the optical path of the edge light of the display panel can be reduced (which can also be regarded as increasing the distribution density of the central light and reducing the distribution density of the edge light), thereby reducing the distortion effect caused by the concave reflective surface.

[0070] The inventors discovered that, during the actual application of the projection device, a portion of the light emitted from the light modulator component 10 to the lens 50 may be reflected at the light incident surface of the lens 50 (i.e., the surface of the lens 50 facing the light modulator component 10), thereby being reflected to the light modulator component 10. The surface of the light modulator component 10 also has a certain reflective effect, which will reflect the light back to the lens 50. If the surface of the lens 50 facing the light modulator component 10 is convex, the light reflected back to the light modulator component 10 by the lens 50 will be unevenly distributed, thereby causing the virtual image observed by the human eye to be uneven. For this reason, in the embodiment of the present disclosure, when the lens 50 is configured as a convex lens, the surface of the lens 50 facing the light modulator component 10 is configured as a plane, and the surface of the lens 50 facing away from the light modulator component 10 is configured as a convex surface. In this case, even if the light incident surface of the lens 50 is reflected, the reflected light is evenly distributed, thereby improving the uniformity of imaging.

[0071] In some embodiments, the reflecting surface of the reflector 30 is mirror-symmetrical about the first reference plane and the second reference line. The first reference plane is a plane passing through the center of the reflecting surface and parallel to the light modulation component 10, and the second reference plane is a plane passing through the center of the reflecting surface and perpendicular to the first reference plane. Therefore, the reflected light of the reflector 30 is also symmetrical about the first reference plane and the second reference plane, so that the virtual image seen by the human eye is also a symmetrical figure.

[0072] In some embodiments, as shown in Figure 10, the central axis Z1 of the lens 50 intersects the transflective mirror 20 at a first intersection O1, and the central axis Z2 of the reflector 30 intersects the first intersection O1. The central axis Z1 of the lens 50 is an axis passing through the center of the lens 50 and parallel to the thickness of the lens 50, while the central axis Z2 of the reflector 30 is an axis passing through the center of the reflector 30 and perpendicular to the tangent plane at the center. In this case, light emitted from the center of the lens 50 is reflected by the transflective mirror 20 to the center of the reflector 30 and then returned by the reflector 30 to the first intersection O1. This prevents off-axis projection and ensures that the observer can see the complete image.

[0073] In some embodiments, a third distance d3 exists between the first intersection O1 and the center of the reflector 30, and a fourth distance d4 exists between the center of the surface of the lens facing the transflector 20 and the first intersection O1. If the fourth distance d4 is less than the third distance d3, the viewer will see the image of the lens 50 in the reflector 30, thus introducing a stray image. Furthermore, some of the light reflected from the reflector 30 may impinge on the lens, disrupting the optical path of the projection device. Therefore, in the disclosed embodiment, the fourth distance d4 is set to be greater than the third distance d3 to prevent the viewer from seeing stray images and ensure normal display of the projection device. For example, d3 = 118 mm and d4 = 129 mm.

[0074] In some embodiments, an antireflection coating is provided on at least the surface of the lens 50 facing away from the light modulation assembly 10 to increase light transmittance, thereby improving light utilization and reducing or preventing reflection of light striking the lens 50 and affecting the normal optical path. Furthermore, both the surface of the lens 50 facing the light modulation assembly 10 and the surface facing away from the light modulation assembly 10 are provided with an antireflection coating.

[0075] In one example, the antireflection film mainly acts on light rays with an angle of 0 to 60 degrees. For example, the transmittance of the antireflection film on light rays with an angle of 0 to 60 degrees is above 99%.

[0076] In some embodiments, more than 90% of the light rays emitted from lens 50 have an exit angle (i.e., the angle between the exit direction and the central axis of the lens) of no greater than 58°. Due to process limitations, the surface of transflective mirror 20 facing lens 50 is not completely flat, but may have slight concave and convex structures. Therefore, some of the light rays emitted from lens 50 toward transflective mirror 20 may return to lens 50 along the same path. In the disclosed embodiments, the refractive index and surface shape of lens 50 are designed to ensure that the angles of light rays emitted from lens 50 are primarily concentrated below 58°. Therefore, even if light rays are reflected back to lens 50 by transflective mirror 20, these rays can pass through the anti-reflection coating without being reflected by lens 50 and affecting the normal optical path.

[0077] Figure 11 is an angular distribution diagram of the output light of the lens 50 provided in some embodiments of the present disclosure, wherein the curve represents the proportion of the curve whose angle does not exceed α. For example, when α=22°, the corresponding angle on the curve accounts for 20%; when α=50°, the corresponding angle on the curve accounts for 90%, that is, the proportion of light with an angle not exceeding 22° is 20%, and the proportion of light with an angle not exceeding 50° is 90%. In other words, the proportion of light with an angle greater than 22° and not exceeding 50° is 70%.

[0078] In some embodiments, the light emitting area of ​​the optical modulation component 10 is rectangular, as shown in FIG12 . A first light shielding layer 71 is disposed on the lens 50. The first light shielding layer 71 is annular, and the inner edge of the annular ring is rectangular. The inner edge length E1 of the annular ring is 2*(tanθ*h+L / 2), and the inner edge width E2 of the annular ring is 2*(tanθ*h+W / 2). The outer edge of the annular ring can coincide with the outer contour of the lens 50. Wherein, 75°≤θ≤85°, L is the length of the light emitting area, W is the width of the light emitting area, and h is the distance between the optical modulation component 10 and the lens 50. For example, θ is 75°, 80°, or 85°.

[0079] It can be understood that the light modulation component 10 is equivalent to a Lambert light source. The brightness of light at a small angle is greater, and the brightness of light at a large angle is smaller. In the embodiment of the present disclosure, through the provision of the first shading layer 71, at least part of the light at a large angle (that is, the angle between the emitted light and the central axis of the light modulation component 10 is greater than θ) is irradiated to the first shading layer 71, thereby preventing the large-angle light from affecting the uniformity of imaging.

[0080] Furthermore, the outer edge length E3 of the annular first light-shielding layer 71 is 2*(tanβ*h+L / 2), the outer edge width E4 of the annular layer is 2*(tanβ*h+W / 2), and 85°<β<90°, thereby completely blocking large-angle light.

[0081] Among them, the outer edge of the first shading layer 71 can be a rectangle or an approximate rectangle; the length E3 of the outer edge is the maximum dimension of the outer edge along the long side of the optical modulation component 10, and the width E4 of the outer edge is the maximum dimension along the short side of the optical modulation component 10.

[0082] The first light shielding layer 71 may be disposed on the surface of the lens 50 facing the light modulation component 10 , or on the surface of the lens 50 away from the light modulation component 10 , or on both surfaces.

[0083] In the embodiments of the present disclosure, the lens 50 can be a solid lens; it can also be a liquid lens. Figure 13 is a schematic diagram of a liquid lens provided in some embodiments of the present disclosure. As shown in Figure 13, in one example, the liquid lens includes a containing cavity 501 and two liquids 502 located inside the containing cavity 501. Since there is a refractive index difference between the two liquids 502 and the two do not mix, a smooth and curved interface can be formed between the two liquids 502, and the interface can be refracted. By applying a voltage to the conductive solution, the way in which the surfaces of the two liquids 502 interact with each other is changed, thereby changing the radius of curvature of the interface. When the lens 50 adopts a liquid lens, the focal length of the lens 50 can be flexibly adjusted to achieve different effects.

[0084] As shown in FIG. 6 , the housing 80 of the projection device may further include a mounting frame 83 . The lens 50 is fixed on one side of the mounting frame 83 , and the light modulation assembly 10 is fixed on the other side of the mounting frame 83 .

[0085] Figure 14 is a schematic diagram of a projection device provided in some further embodiments of the present disclosure. As shown in Figure 14, in some embodiments, the projection device may further include: a first quarter-wave plate 61, a second quarter-wave plate 62 and a polarizer 63, wherein the first quarter-wave plate 61 is arranged on the side of the dimming film 40 away from the light modulation component 10; the second quarter-wave plate 62 is arranged on the side of the transflector 20 away from the light modulation component 10; and the polarizer 63 is arranged on the side of the second quarter-wave plate 62 away from the transflector 20.

[0086] Among them, the transflective mirror 20 has a metal transflective film and the reflector 30 has a metal reflective layer. The light emitted by the optical modulation component 10 is linearly polarized light. Taking the linearly polarized light as O light as an example, the O light becomes left-handed polarized light after passing through the first quarter-wave plate 61, and does not change its polarization state after passing through the lens 50. After then being reflected by the transflective mirror 20, the metal transflective film on the transflective mirror 20 and the metal reflective layer of the reflector 30 have a phase absorption effect, thereby causing the left-handed polarized light to become E light. The E light is reflected by the reflector 30 and becomes right-handed polarized light. The right-handed polarized light does not change its polarization state after being transmitted through the transflective mirror 20. After passing through the second quarter-wave plate 62, the right-handed polarized light becomes O wave, and then is emitted through the polarizer 63 without polarization state loss. The external ambient light becomes O wave after passing through the polarizer 63. The O wave becomes right-handed polarized light after passing through the second quarter-wave plate 62. The right-handed polarized light becomes E wave after being reflected by the reflective mirror 20. The E wave becomes left-handed polarized light after passing through the second quarter-wave plate 62. The left-handed polarized light cannot be emitted after passing through the polarizer 63. It can be seen that the external ambient light cannot enter the human eye through the internal optical path, thereby reducing external stray light.

[0087] In some embodiments, the illumination area of ​​the light reflected by the reflector 30 on the transflector 20 is the effective area 201, and the polarizer 63 and the second quarter-wave plate 62 both cover at least the effective area of ​​the transflector 20 to ensure that external ambient light does not enter the internal optical path of the projection device. Figure 15 is a schematic diagram of the effective area on the reflector 20 provided in some embodiments of the present disclosure. As shown in Figure 15, when the light-emitting area of ​​the optical modulation component 10 is a rectangle, the effective area 201 is an isosceles trapezoid, the short side and the long side of the isosceles trapezoid are parallel to the long side of the light-emitting area, and the short side of the isosceles trapezoid is a side of the isosceles trapezoid close to the optical modulation component 10, the length of the long side of the isosceles trapezoid is: L*m, the length of the short side of the isosceles trapezoid is: L*m*cosA, and the waist length of the isosceles trapezoid is: W*m*cosA; wherein, L is the length of the light-emitting area of ​​the optical modulation component 10, W is the width of the light-emitting area, A is the angle between the extension surface of the reflector 20 and the extension surface of the optical modulation component 10 (as shown in Figure 14), and m is the magnification of the reflector 30.

[0088] In one example, m is greater than 1, and A is greater than 0° and less than 90°. For example, m is between 2 and 4, and A is between 25° and 50°; for example, m=2.55, and A=38°.

[0089] In one example, the polarizer 63 and the second quarter-wave plate 62 may only cover the active area 201 of the transflective mirror 20 ; in another example, the polarizer 63 and the second quarter-wave plate 62 may cover the entire area of ​​the transflective mirror 20 .

[0090] In some embodiments, the projection device further includes a half-wave plate 64 disposed between the first quarter-wave plate 61 and the dimming film 40. The orthographic projection of the half-wave plate 64 on the light modulator 10 overlaps the orthographic projection of the first quarter-wave plate 61 on the light modulator 10. Placing the first quarter-wave plate 61 on the light-emitting side of the light modulator 10 can effectively treat light with a wavelength of approximately 550 nm. However, the light modulator 10 emits visible light, which has a wavelength range of 380-750 nm. Placing only the first quarter-wave plate 61 on the light-emitting side of the light modulator 10 can easily cause color shift. However, placing the half-wave plate 64 in the light path can convert linearly polarized light in a large wavelength range into elliptically polarized light without changing the overall polarization state, thereby reducing image color changes. Furthermore, when the first quarter-wave plate 61 is disposed, since the first quarter-wave plate 61 and the dimming film 40 form a double-slit structure, light interference is likely to occur, resulting in interference fringes. After the half wave plate 64 is added, the half wave plate 64 can convert the elliptically polarized light emitted by the display panel into linearly polarized light, thereby destroying the interference of light and further improving the moiré pattern in the display image.

[0091] In some embodiments, a second light-shielding layer 72 is provided on the surface of the transflective mirror 20 facing away from the reflective mirror 30. The second light-shielding layer 72 covers at least a portion of the inactive area 202. In applications of projection devices, some light may not pass through the transflective mirror 20, but instead directly strike the reflective mirror 30 after passing through the lens 50, and then be emitted from the reflective mirror 30 to the transflective mirror 20, and thus to the human eye. Obviously, this portion of light follows a different optical path from the normal light path, thereby generating stray light. In the disclosed embodiments, by providing the second light-shielding layer 72 on at least a portion of the inactive area 202, the generation of stray light can be reduced.

[0092] Furthermore, the stray light usually appears in the portion of the inactive area 202 located on the side of the active area 201 close to the light modulation component 10 (referred to as the first inactive area 202a). Therefore, the second light shielding layer 72 at least covers the first inactive area 202a to prevent stray light.

[0093] In some embodiments, the positions of the light modulation assembly 10, lens 50, and transflective mirror 20 in the projection device remain relatively fixed. In other embodiments, the projection device may further include an adjustment member (not shown) connected to the light modulation assembly 10 for adjusting the position of the light modulation assembly 10 to move the light modulation assembly 10 closer to or further away from the transflective mirror 20. The movement distance D of the light modulation assembly 10 satisfies the following formula:

[0094] D=a*VID^b+c

[0095] Where VID is the virtual image distance, that is, the distance between the human eye and the virtual image; a, b, and c are preset parameters: -133 < a < -134, -1.5 < b < -1.2, and 10 < c < 11. In one example, a = -133.3, b = -1.424, and c = 10.42. When D = 0, the distance between the center of the light modulation assembly 10 and the center of the transflective mirror 40 is 160 mm.

[0096] In a specific example, the projection device adopts the structure of Figure 14. The center thickness of the lens 50 is 27 mm. The fourth distance d4 is 129 mm, the third distance d3 is 118 mm, the surface of the lens 50 facing away from the light modulation assembly 10 is convex and has a radius of curvature of 230 mm, the radius of curvature of the reflector 30 is 550 mm, and the angle A between the extended surface of the transflective mirror 20 and the extended surface of the light modulation assembly 10 is 38°. The optical characteristics of the projection device of this example are simulated as follows:

[0097] Figure 16 shows an MTF (Modulation Transfer Function) plot for a projection device provided in an example of the present disclosure. The MTF plot is a relatively scientific method for analyzing the resolution of a projection device. The unit of resolution for a projection device is line pairs per millimeter. Two adjacent black and white lines are considered a line pair, and the number of line pairs that can be resolved per millimeter is the resolution. The resolution of a projection device is tested by photographing a sinusoidal grating (the black and white grid on a test target). A periodic pattern with sinusoidal brightness variations is called a "sinusoidal grating." The density of the sinusoidal grating is called the "spatial frequency," and the unit of spatial frequency is "cycles / mm." "Cycles / mm" represents the number of cycles of a pattern with sinusoidal brightness variations per unit length (per millimeter). The multiple lines in Figure 16 represent the MTF curves for the edge of the maximum field of view in the tangential and sagittal directions, as well as the MTF curves for the edge of the minimum field of view in the tangential and sagittal directions. The numerical values ​​marked on each curve represent the horizontal and vertical coordinates of the field of view. As can be seen from FIG16 , the MTF value of the field of view of the projection device provided by the embodiment of the present disclosure is high, and the imaging clarity of the projection device is high.

[0098] Figure 17 shows a spot diagram of a projection device provided in an example of the present disclosure. The two data points labeled below each field of view represent the horizontal and vertical coordinates of the field of view. The two rows of data at the bottom of Figure 17 represent quantitative indicators for nine fields of view. The nine data points in the first row represent the root mean square radius of the light areas formed by the object plane on nine image planes of different sizes, while the data in the second row represent the geometric radius of the light areas formed by the object plane on nine image planes of different sizes. Spot diagrams are one of the most commonly used evaluation methods in modern optical design. The principle of a spot diagram is to display the image formed by an optical system on the image plane. In other words, it calculates and plots the image formed on the image plane by a series of object-space points after they pass through the optical system. For ease of presentation, a series of predefined templates can be selected. Specifically, for example, for a point on an axis, the design process uses a reverse light path to simulate several light-emitting points. These points pass through the optical system and are ultimately imaged on the light modulation assembly 10. If the optical system is perfect, the image formed by these points will be an ideal point. However, for an actual optical system, it will be imaged as a diffuse spot, and the image of this diffuse spot on the light modulating component 10 is the point diagram. The quality of the optical design can be observed through the point diagram, and the smaller the diffuse spot, the better. If it is found that the diffuse spot is small enough to meet the requirements for the minimum diffuse spot of the optical system (the unit of the point diagram is micrometers), then the design of the optical system is completed. Among them, in the embodiment of the present disclosure, through the above-mentioned design of the projection device, the root mean square radius of the light spot in each field of view from the central field of view to the edge field of view is less than or equal to the Airy disk, and approaches the diffraction limit. Among them, the central field of view refers to the light emitted from the center point of the virtual image, and the edge field of view is the light emitted from the edge position of the virtual image.

[0099] FIG18 shows a diagram of field curvature and distortion of a projection device provided in some embodiments of the present disclosure. Field curvature is also known as "field curvature." When lens 50 exhibits field curvature, the intersection of the entire light beam does not coincide with the ideal image point. Although a clear image point can be obtained at each specific point, the entire image plane is a curved surface. This prevents simultaneous viewing of the entire image plane during microscopic examination, making imaging difficult. The projection device in the embodiments of the present disclosure has a maximum field of view of 78.526 mm, a sagittal field curvature of 5.8217 mm, and a meridional field curvature of 5.3756 mm. The projection device exhibits low dispersion for the three RGB colors; the maximum distortion is 3.0612%, and the image exhibits low barrel distortion and pincushion distortion.

[0100] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A projection device, comprising: A light modulation component, a dimming film, a transflective mirror and a reflective mirror; the dimming film is arranged on the light-emitting side of the light modulation component, and the transflective mirror is arranged on the side of the dimming film away from the light modulation component; After passing through the dimming film, the plurality of first light rays emitted by the light modulation component form corresponding plurality of second light rays that are emitted toward the transflective mirror, and at least a portion of the second light rays are reflected by the transflective mirror toward the reflective mirror, and then reflected by the reflective mirror to be emitted from the transflective mirror; Among the multiple first light rays, the first light rays with a divergence angle greater than a first preset value are target light rays, and the divergence angle of the second light rays corresponding to at least some of the target light rays is smaller than the divergence angle of the target light rays.

2. The projection device according to claim 1, wherein: The extended surface of the transflective mirror intersects with the extended surface of the light modulation component at a first intersection line; Among them, a part of the multiple target light rays emitted by the light modulation component is the first target light ray, the orthographic projection of the first target light ray on the light modulation component is perpendicular to the first intersection line, and the divergence angle of the first target light ray is greater than the second preset value, and the second preset value is greater than the first preset value; the divergence angle of the second light ray corresponding to the first target light ray is less than or equal to the second preset value.

3. The projection device according to claim 1, wherein: The projection device further includes a lens, which is disposed between the dimming film and the transflective mirror. One of the surface shapes of the lens and the surface shape of the reflective mirror is convex, and the other is concave.

4. The projection device according to claim 3, wherein: At least part of the light emitted from the lens is reflected by the reflective mirror to the reflector, wherein, for multiple light rays emitted from the lens to the reflector, there is a first distance between the exit position of the light on the lens and the central axis of the lens, and there is a second distance between the incident position of the light path on the reflector and the central axis of the reflector, and the first distance is positively correlated with the second distance.

5. The projection device according to claim 4, wherein: The reflecting surface of the reflector is a concave surface, and the lens is a convex lens.

6. The projection device according to claim 5, wherein: The surface of the lens facing the light modulation component is a plane, and the surface of the lens facing away from the light modulation component is a convex surface.

7. The projection device according to claim 4, wherein: The reflecting surface of the reflector is mirror-symmetrical about a first reference plane and a second reference line. The first reference plane is a plane passing through the center of the reflecting surface and parallel to the light modulation component, and the second reference plane is a plane passing through the central axis of the reflecting surface and perpendicular to the first reference plane.

8. The projection device according to claim 3, wherein: The central axis of the lens intersects the transflective mirror at a first intersection, and the central axis of the reflective mirror intersects the first intersection.

9. The projection device according to claim 8, wherein: There is a third distance between the first intersection point and the center of the reflector, and there is a fourth distance between the center of the surface of the lens facing the transflective mirror and the first intersection point, and the fourth distance is greater than the third distance.

10. The projection device according to claim 3, wherein: An anti-reflection film is provided at least on the surface of the lens facing away from the light modulation component.

11. The projection device according to claim 3, wherein: The light emitting area of ​​the light modulation component is rectangular, a first light-shielding layer in a ring shape is provided on the lens, the inner edge of the ring shape is rectangular, and the length of the inner edge of the ring shape is 2*(tanθ*h+L / 2), and the width of the inner edge of the ring shape is 2*(tanθ*h+W / 2), wherein 75°≤θ≤85°, L is the length of the display area, W is the width of the display area, and h is the distance between the light modulation component and the lens.

12. The projection device according to claim 3, wherein: The lens is a solid lens or a liquid lens.

13. The projection device according to any one of claims 1 to 12, wherein: The projection device further comprises: A first quarter wave plate is arranged on a side of the dimming film away from the light modulation component; A second quarter-wave plate is arranged on a side of the transflective mirror away from the light modulation component; The polarizer is arranged on a side of the second quarter-wave plate away from the transflective mirror.

14. The projection device according to claim 13, wherein: The polarizer and the second quarter-wave plate both cover at least the effective area of ​​the transflective mirror; the light-emitting area of ​​the light modulation component is rectangular; the effective area is an isosceles trapezoid; the short side and the long side of the isosceles trapezoid are both parallel to the long side of the light-emitting area; the long side length of the isosceles trapezoid is: L*m; the short side length of the isosceles trapezoid is: L*m*cosA; and the waist length of the isosceles trapezoid is: W*m*cosA; Wherein, L is the length of the light emitting area of ​​the light modulation component, W is the width of the light emitting area, A is the angle between the extension surface of the transflective mirror and the extension surface of the light modulation component, and m is the magnification of the reflector.

15. The projection device according to claim 13, wherein: The projection device further includes: a half wave plate, which is arranged between the first quarter wave plate and the dimming film, and the orthographic projection of the half wave plate on the light modulation component covers the orthographic projection of the first quarter wave plate on the light modulation component.

16. The projection device according to any one of claims 1 to 12, wherein: The transflective mirror includes an effective area and an ineffective area surrounding the effective area, wherein the effective area is an irradiation area of ​​the transflective mirror by the reflected light of the reflector; Wherein, a second light-shielding layer is provided on the surface of the transflective mirror facing away from the reflective mirror, and the second light-shielding layer covers at least a portion of the ineffective area.

17. The projection device according to claim 16, wherein: The ineffective area includes a first ineffective area located at a side of the effective area close to the light modulation component, and the second light shielding layer at least covers the first ineffective area.

Images