Projection device

Abstract

The projection device comprises a light modulation assembly, a dimming film, a transflective mirror and a reflector, the dimming film is arranged on the light emitting side of the light modulation assembly, and the transflective mirror is arranged on the side, away from the light modulation assembly, of the dimming film; after a plurality of first light rays emitted by the light modulation assembly pass through the dimming film, a plurality of corresponding second light rays are formed and emitted to the transflective mirror, and at least part of the second light rays are reflected to the reflecting mirror by the transflective mirror and are reflected to the transflective mirror by the reflecting mirror to be emitted; wherein in the multiple first light rays, the first light rays with the divergence angles larger than a first preset value are target light rays, and the divergence angles of the second light rays corresponding to at least part of the target light rays are smaller than the divergence angles of the target light rays.

Description

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 products used to prevent myopia. In telescopic screen products, the light from the display screen is reflected into the human eye and forms a long-distance 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. Utility Model Content

[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 a plurality of corresponding second light rays emitted toward the transflective mirror, and at least part of the second light rays are reflected by the transflective mirror to 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 whose divergence angle is greater than the 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 are first target light rays, the orthographic projection of the first target light rays on the light modulation component is perpendicular to the first intersection line, and the divergence angle of the first target light rays 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 rays corresponding to the first target light rays is less than or equal to the second preset value.

[0008] In some embodiments, the projection device further includes a lens, wherein the lens is disposed between the dimming film and the transflective mirror, and 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 outgoing light of the lens is reflected by the reflector to the reflector, wherein, for a plurality of 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-symmetric 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 with the transflective mirror at a first intersection, and a central axis of the reflective mirror intersects with the first intersection.

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

[0015] In some embodiments, an anti-reflection film is disposed at least on a 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 ring-shaped shading layer is arranged on the lens, the inner edge of the ring is rectangular, and the length of the inner edge of the ring is 2*(tanθ*h+L / 2), and the width of the inner edge of the ring 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 transflector away from the light modulation component;

[0021] A 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 transflector, the light-emitting area of ​​the light modulation component is a rectangle, 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, wherein the half wave plate is disposed 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 irradiation area of ​​the reflected light of the reflector on the transflective mirror;

[0026] Wherein, a second light-shielding layer is arranged on a 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 ineffective area includes a first ineffective region located on a side of the effective area close to the light modulation component, and the second light shielding layer at least covers the first ineffective 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 specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0029] Figure 1 A schematic diagram of a projection device provided in an example.

[0030] Figure 2 It is a stereoscopic diagram of a projection device provided in some embodiments of the present disclosure.

[0031] Figure 3 It is a cross-sectional view of a projection device provided in some embodiments of the present disclosure.

[0032] Figure 4 It is a stereoscopic diagram of a projection device provided in some other embodiments of the present disclosure.

[0033] Figure 5 sectional views of projection devices provided in other embodiments of the present disclosure.

[0034] Figure 6 It is an exploded view of a projection device provided in some other embodiments of the present disclosure.

[0035] Figure 7 It is a cross-sectional view along the short side direction of the light modulation component.

[0036] Figure 8 It 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] Fig. 9 Schematic diagram of the shape of the image when the reflecting surface is a plane and a concave surface respectively.

[0038] Fig.10 A schematic diagram of relevant dimensions in a projection device provided in some embodiments of the present disclosure.

[0039] Fig.11 This is a diagram showing the angular distribution of the outgoing light rays of the lens provided in some embodiments of the present disclosure.

[0040] Fig.12 It is a plan view of the lens and the first light-shielding layer provided in some embodiments of the present disclosure.

[0041] Fig.13 Schematic diagram of a liquid lens provided in some embodiments of the present disclosure.

[0042] Fig.14 Schematic diagram of a projection device provided in some further embodiments of the present disclosure.

[0043] Fig.15 It is a schematic diagram of the effective area on the transflective mirror provided in some embodiments of the present disclosure.

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

[0045] Fig.17 This is a spot diagram of a projection device provided in an example of the present disclosure.

[0046] Fig.18 Field curvature diagram and distortion diagram of the projection device provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0047] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the 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 be 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 represent any order, quantity or importance, but are only used to distinguish different components. Similarly, "including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can 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 described object changes, the relative positional relationship may also change accordingly.

[0050] As used herein, "parallel" and "perpendicular" include the described situation and the situation similar to the described situation, and the range of the similar situation is within the 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 error associated with the measurement of a specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°.

[0051] It will be understood that when a layer or an 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 between the layer or element and the other layer or substrate.

[0052] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness 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 conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but 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 shapes 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 long-distance 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 FIG. 1 is a schematic diagram of a projection device provided in an example, and the projection device can be used as a telescopic screen product. Figure 1 As shown, the light modulation component 10 is used to provide image light. For example, the light modulation component 10 is a display panel, and the display panel can be a liquid crystal display panel. The image light of the light modulation component 10 is irradiated to the transflective mirror 20, and the transflective mirror 20 irradiates a part of the received image light to the reflector 30. The light is reflected by the reflector 30 to the transflective mirror 20, and then irradiates to the eye box area 90 (eye box) through the transflective mirror 20. When the observer's eyes are located in the eye box area 90, the light output by the projection device can be received, so that the virtual image 91 can be seen against the direction of the light. The eye box area 90 specifically refers to the area where the observer's eyes are located and the image output by the projection device can be seen. The eye box area 90 has a certain size. Even if the observer's eyes deviate from the center of the eye box area 90 by a certain distance, such as a certain distance in the up and down or left and right directions, as long as they are still in the eye box area 90, the image output by the projection device can be seen.

[0055] The inventors have found that the large-angle light L11 emitted by the light modulation component 10 will pass through the transflector 20 and directly emit to the eye box area 90, and these lights do not pass through the normal reflection path (that is, they are not reflected by the reflector), that is, these lights are equivalent to stray light. As for the small-angle light L12 emitted by the light modulation component 10, even if these lights directly pass through the transflector 20, they will not be emitted to the eye box area 90, and thus will not affect the viewing experience of the observer.

[0056] Figure 2 is a stereoscopic diagram 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 4is a stereoscopic diagram of a projection device provided in some other embodiments of the present disclosure, Figure 5 is a cross-sectional view of a projection device provided in some other embodiments of the present disclosure, Figure 6 Detailed description of the projection device provided in some other embodiments of the present disclosure. Figures 2 to 6 As shown, 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 (such as a glass substrate) and a transflective film disposed on the transparent substrate.

[0058] The dimming film 40 is arranged on the light-emitting side of the optical modulation component 10, and is located between the optical modulation component 10 and the transflective mirror 20, that is, the output light of the optical modulation component 10 passes through the dimming film 40 and is emitted to the transflective mirror 20. The dimming film 40 is used to adjust the angle of at least part of the light. Specifically, after the multiple first light beams L1 emitted by the optical modulation component 10 pass through the dimming film 40, they form corresponding multiple second light beams L2 and are emitted to the transflective mirror 20, and each first light beam L1 corresponds to a second light beam L2; wherein, among the multiple first light beams L1, the first light beam L1 with a divergence angle greater than the first preset value is used as the target light beam, and the divergence angle of the second light beam L2 corresponding to at least part of the target light beam is smaller than the divergence angle of the target light beam. In other words, the divergence angle of at least part of the first light beam L1 with a large angle is reduced 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 reflective mirror 20 is disposed on a side of the dimming film 40 away from the light modulation component 10. Among the multiple second light rays L2 directed to the reflective mirror 20, at least part of the second light rays L2 are reflected by the reflective mirror 20 to the reflective mirror 30, and then reflected by the reflective mirror 30 to the reflective mirror 20 and emitted, thereby emitting to the eye box area for viewing by the observer. It should be noted that the drawings of the present disclosure only schematically show the relative positional relationship between the various components, and do not strictly indicate the size of the gap between the components. For example, in the cross-sectional views of each projection device, in order to clearly see the light changes, a gap is indicated between the reflective mirror 20 and the light modulation component 10, but in fact, there may be no gap between the two, and the reflective mirror 20 may be attached to the light emitting surface of the light modulation component 10. In this case, the first light ray L1 can be regarded as the light emitted by the light modulation component 10 when the reflective 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 viewing experience of the observer.

[0062] In some embodiments, the extended surface of the reflective mirror 20 intersects with the extended surface of the light modulation component 10 at a first intersection line. Figure 6 As shown, the projection device may further include a housing 80, the housing 80 includes a first side wall 81 and a second side wall 82 that are arranged opposite to each other, the first side wall 81 and the second side wall 82 are both perpendicular to the first intersection line, and the reflector 20 and the light modulation component 10 are arranged between the first side wall 81 and the second side wall 82. In this case, if the positive projection of a first light ray L1 with a large angle on the light modulation component 10 is parallel to the first intersection line, then even if the angle of the first light ray L1 is not adjusted, the first light ray L1 is emitted toward the first side wall 81 and the second side wall 82, and is thus absorbed by the housing 80, and will not be emitted toward the human eye to generate stray light. Therefore, in the embodiment of the present disclosure, the dimming film 40 only needs to adjust a part of the target light emitted by the light modulation component 10.

[0063] For example, a portion of the multiple target light rays emitted by the optical modulation component 10 is the first target light ray, the orthographic projection of the first target light ray on the optical modulation component 10 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 L2 corresponding to the first target light ray is less than the above-mentioned second preset value. That is, after the first light ray L1 whose divergence angle is greater than the second preset value and whose orthographic projection is perpendicular to the first intersection line is adjusted by the dimming film 40, the divergence angle is less than the divergence angle before adjustment. In addition, another portion of the multiple first light rays L1 is the second target light ray, and the orthographic projection of the second target light ray on the optical modulation component 10 is parallel to the first intersection line, and the dimming film 40 may not adjust the angle of the second target light ray, that is, the divergence angle of the second light ray L2 corresponding to the second target light ray is equal to the divergence angle of the second target light ray.

[0064] For example, the dimming film 40 is a grid structure, which includes a plurality of bars, each of which extends in a direction parallel to the first intersection line, and is arranged in a direction 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 plurality of first target light rays pass through the dimming film 40, the divergence angles of most or all of the plurality of 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 plurality of 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 not greater than 25°, and the divergence angle of the second light ray L2 corresponding to the second target light ray is not greater than 90°. Figure 7 It is a cross-sectional view along the short side direction of the light modulator 10. Taking the light modulator 10 as a rectangle with the long side in the long direction parallel to the first intersection line as an example, in the short side direction of the light modulator 10, the divergence angle γ of the light emitted by the dimming film 40 is not greater than 25°; in the long side direction of the light modulator 10, the divergence angle of the light emitted by the dimming film 40 is not greater than 90°.

[0067] Figure 8 FIG. 1 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 Figure 1 The structure shown in the figure, the projection device disclosed in the present invention adopts Fig.14 The structure shown, Fig.14 exist Figure 1 On the basis of the light modulator 10, the light modulator 40 is added, and in the long side direction of the light modulator 10, the light modulator 40 does not change the angle of the light; in the short side direction of the light modulator 10, the light modulator 40 adjusts the light beam angle to within 50°, that is, the angle between the light emission direction and the central axis of the light modulator 40 is within 25°. Figure 8 In the image, "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. Figure 8 It can be seen that in the embodiment of the present disclosure, the generation of stray images can be reduced by disposing the dimming film 40 .

[0068] In some embodiments, Figures 4 to 6 As shown, 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, and one of the surface shapes of the lens 50 and the reflector 30 is a convex surface, and the other is a concave surface. After the second light L2 is emitted to the lens 50, it is adjusted by the lens 50, and the adjusted second light L2 is emitted to the transflective mirror 20. Among them, at least part of the emitted light of the lens 50 is reflected to the reflector 30 by the transflective mirror 20, and for a plurality of light rays emitted from the lens 50 to the reflector 30, there is a first distance between the emitted position of the light on the lens 50 and the central axis of the lens 50, and there is a second distance between the incident position of the light path on the reflector 30 and the central axis of the reflector 30, and the first distance is positively correlated with the second distance. That is to say, the closer the light emitted from the position to the center of the lens 50 is, the closer the incident position on the reflector 30 is to the center of the reflector 30 , and the farther the light emitted from the position to the center of the lens 50 is, the farther the 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 a concave surface, 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 a concave surface, 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. Since the reflective surface is a concave surface, the optical path of the edge light of the display panel is large, and the optical path of the center light is small. It can also be seen that the concave reflective surface will cause the edge light to be dense and the center light to be sparse, which will cause the image seen by the human eye to be distorted. Fig. 9Schematic diagram of the shape of the image when the reflecting surface is a plane and a concave surface respectively. When the reflecting surface is a plane, the virtual image 91 seen by the human eye is a rectangle; when the reflecting surface is a concave surface, the virtual image 91' seen is no longer a rectangle, but a shape with four convex arcs. 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 (it 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 reflecting surface.

[0070] The inventors have found that, in the actual application of the projection device, a portion of the light emitted from the light modulation 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 modulation component 10), and thus reflected to the light modulation component 10, and the surface of the light modulation component 10 also has a certain reflection effect, and then reflects the light to the lens 50 again. If the surface of the lens 50 facing the light modulation component 10 is a convex surface, the light reflected from the lens 50 back to the light modulation component 10 will be unevenly distributed, and thus the virtual image observed by the human eye will be uneven. For this reason, in the embodiment of the present disclosure, when the lens 50 is set as a convex lens, the surface of the lens 50 facing the light modulation component 10 is set as a plane, and the surface of the lens 50 away from the light modulation component 10 is set 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, Fig.10 As shown, the central axis Z1 of the lens 50 intersects with the transflective mirror 20 at the first intersection O1, and the central axis Z2 of the reflector 30 intersects with the first intersection O1. The central axis Z1 of the lens 50 refers to an axis passing through the center of the lens 50 and parallel to the thickness direction of the lens 50, and the central axis Z2 of the reflector 30 refers to an axis passing through the center of the reflector 30 and perpendicular to the tangent plane at the center. In this case, the light emitted from the center of the lens 50 is reflected by the transflective mirror 20 to the center of the reflector 30, and is returned to the first intersection O1 by the reflector 30 along the original path, thereby preventing off-axis projection from occurring to ensure that the observer can see the complete image.

[0073] In some embodiments, there is a third distance d3 between the first intersection O1 and the center of the reflector 30, and there is a fourth distance d4 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, that is, a stray image is introduced; in addition, a portion of the reflected light from the reflector 30 may irradiate the lens, thereby disrupting the optical path of the projection device. For this reason, in the embodiment of the present disclosure, the fourth distance d4 is set to be greater than the third distance d3, so as to prevent the observer from seeing stray images and ensure the normal display of the projection device. For example, d3 = 118 mm, d4 = 129 mm.

[0074] In some embodiments, at least the surface of the lens 50 facing away from the light modulation component 10 is provided with an anti-reflection film, so as to improve the transmittance of light, thereby improving the light utilization rate, and reducing or preventing the light irradiated to the lens 50 from being reflected and affecting the normal light path. Further, both the surface of the lens 50 facing the light modulation component 10 and the surface facing away from the light modulation component 10 are provided with an anti-reflection film.

[0075] In one example, the anti-reflection film mainly acts on light rays within a range of 0 to 60 degrees. For example, the transmittance of the anti-reflection film to light rays within a range of 0 to 60 degrees is above 99%.

[0076] In some embodiments, among the light rays emitted from the lens 50, the angle of emission (i.e., the angle between the emission direction and the central axis of the lens) of more than 90% of the light rays is no greater than 58°. Due to the limitation of process conditions, the surface of the transflective mirror 20 facing the lens 50 is not a completely flat plane, but may have a tiny concave-convex structure. Therefore, among the light rays emitted from the lens 50 to the transflective mirror 20, a part of the light rays may return to the lens 50 along the original path. The embodiment of the present disclosure designs the refractive index and the surface shape of the lens 50 so that the angle of the light rays emitted from the lens 50 is mainly concentrated below 58°. Therefore, even if the light rays are reflected back to the lens 50 by the transflective mirror 20, this part of the light rays can pass through the anti-reflection film, and will not be reflected by the lens 50 and affect the normal light path.

[0077] Fig.11 It is an angular distribution diagram of the outgoing light of the lens 50 provided in some embodiments of the present disclosure, wherein the curve represents the proportion of the curve with an angle not exceeding 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 light with an angle not exceeding 22° accounts for 20%, and the light with an angle not exceeding 50° accounts for 90%, that is to say, the light with a angle greater than 22° and not exceeding 50° accounts for 70%.

[0078] In some embodiments, the light emitting area of ​​the light modulation component 10 is rectangular, such as Fig.12As shown, a first light shielding layer 71 is provided on the lens 50, the first light shielding layer 71 is annular, the inner edge of the annular shape is rectangular, and the inner edge length E1 of the annular shape is 2*(tanθ*h+L / 2), the inner edge width E2 of the annular shape is 2*(tanθ*h+W / 2), and the outer edge of the annular shape 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 light modulation component 10 and the lens 50. For example, θ is 75°, or 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 shading 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°, so that all large-angle light can be blocked.

[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 of the outer edge 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 embodiment of the present disclosure, the lens 50 may be a solid lens; or a liquid lens. Fig.13 Schematic diagram of a liquid lens provided in some embodiments of the present disclosure, such as Fig.13 As shown, in one example, the liquid lens includes a containing cavity 501 and two liquids 502 located inside the containing cavity 501. Since the two liquids 502 have a refractive index difference and the two liquids 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 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] like Figure 6As shown, 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] Fig.14 Schematic diagram of a projection device provided in some other embodiments of the present disclosure, such as Fig.14 As shown, 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 reflective mirror 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 reflective mirror 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 linear 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 the polarization state after passing through the lens 50. After that, after 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, so that the left-handed polarized light becomes E light. The E light becomes right-handed polarized light after being reflected by the reflector 30. The right-handed polarized light does not change the 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, and 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, and 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 the external ambient light does not enter the internal optical path of the projection device. Fig.15 Schematic diagram of the effective area on the reflective mirror 20 provided in some embodiments of the present disclosure, such as Fig.15As shown, when the light emitting area of ​​the light modulator 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 light modulator 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 light modulator 10, W is the width of the light emitting area, and A is the angle between the extension surface of the reflective mirror 20 and the extension surface of the light modulator 10 (such as Fig.14 ), m is the magnification of the reflecting mirror 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 effective 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, the half wave plate 64 is arranged between the first quarter wave plate 61 and the dimming film 40, and the orthographic projection of the half wave plate 64 on the light modulation component 10 covers the orthographic projection of the first quarter wave plate 61 on the light modulation component 10. Among them, the first quarter wave plate 61 is arranged on the light-emitting side of the light modulation component 10, which can have an effect on light with a wavelength of about 550nm, but the light modulation component 10 is visible light, and its light band is 380-750nm. If only one first quarter wave plate 61 is placed on the light-emitting side of the light modulation component 10, color deviation is likely to occur. After the half wave plate 64 is arranged in the light path, the linear polarization of most bands can be converted into elliptically polarized light without changing the overall polarization state, thereby reducing the change in the color of the picture. In addition, when the first quarter wave plate 61 is arranged, since the first quarter wave plate 61 and the dimming film 40 can 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 transform 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 disposed on the surface of the transflective mirror 20 facing away from the reflective mirror 30, and the second light shielding layer 72 covers at least a portion of the ineffective area 202. In the application of the projection device, there may be some light that does not pass through the transflective mirror 20, but directly shoots toward the reflective mirror 30 after passing through the lens 50, and is then shot toward the transflective mirror 20 by the reflective mirror 30, and then toward the human eye. Obviously, this part of the light is different from the normal light path, thereby forming stray light; in the embodiment of the present disclosure, by disposing the second light shielding layer 72 on at least a portion of the ineffective area 202, the generation of stray light can be reduced.

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

[0093] In some embodiments, the positions of the light modulation component 10, the lens 50, and the transflective mirror 20 in the projection device remain relatively fixed. In other embodiments, the projection device may further include an adjustment member (not shown), which is connected to the light modulation component 10 and is used to adjust the position of the light modulation component 10 so that the light modulation component 10 moves closer to the transflective mirror 20 or away from the transflective mirror 20. The moving distance D of the light modulation component 10 satisfies the following formula:

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

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

[0096] In a specific example, the projection device uses Fig.14 The structure of the projection device 50 is shown in FIG. 1 , the center thickness of the lens 50 is 27 mm, the fourth distance d4 is 129, the third distance d3 is 118, the surface of the lens 50 away from the light modulation component 10 is a convex surface, and the radius of curvature is 230 mm, the radius of curvature of the reflector 30 is 550 mm, and the angle A between the extension surface of the transflector 20 and the extension surface of the light modulation component 10 is 38. The optical characteristics of the projection device of this example are simulated as follows:

[0097] Fig.16The Modulation Transfer Function (MTF) diagram of a projection device provided in an example of the present disclosure. The MTF diagram is a relatively scientific method for analyzing the resolution of a projection device. The unit of the resolution of a projection device is line pair / mm. Two adjacent black and white lines can be called a line pair. The number of line pairs that can be distinguished per millimeter is the resolution. The resolution of the projection device is tested by shooting a sinusoidal grating (the black and white grid in the test target plate). A periodic figure whose brightness changes sinusoidally is called a "sinusoidal grating". The density of the sinusoidal grating is called the "spatial frequency", and the unit of the spatial frequency is expressed in "cycles / mm". "Cycles / mm" represents the number of cycles of the figure whose brightness per unit length (per millimeter) changes sinusoidally. Fig.16 The multiple lines in the figure represent the MTF curves of the edge position of the maximum field of view in the meridian and sagittal directions, and the MTF curves of the edge position of the minimum field of view in the meridian and sagittal directions. The values ​​marked on each curve represent the horizontal and vertical coordinates of the field of view. Fig.16 It can be seen that 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] Fig.17 This is a point arrangement diagram of a projection device provided in an example of the present disclosure, and the two data marked below each field of view represent: the horizontal and vertical coordinates of the field of view. Fig.17The two rows of data in the middle and lower part represent the quantitative indicators of the nine fields of view, among which the nine data in the first row represent the root mean square radius of the light area formed by the object plane on the nine image planes of different sizes, and the data in the second row represent the geometric radius of the light area formed by the object plane on the nine image planes of different sizes. The spot diagram is one of the most commonly used evaluation methods in modern optical design. The principle of the spot diagram is to display the imaging of the optical system on the image plane. In other words, it actually draws the situation of imaging on the image plane after a series of object points pass through the optical system through calculation. For the convenience of expression, it can select a series of predetermined template forms. Specifically, for example, a point on the axis, the design process adopts the reverse light path to simulate several light-emitting points, which pass through the optical system and finally form an image on the light modulation component 10. If the optical system is a perfect optical system, then the imaging point of these points is an ideal point. But for the actual optical system, it will be imaged as a diffuse spot, and the image of this diffuse spot on the light modulation component 10 is the spot diagram. The quality of the optical design can be observed through the spot diagram. The smaller the diffuse spot, the better. If it is found that the diffuse spot is small enough to meet the requirements of the minimum diffuse spot of the optical system (the unit of the spot diagram is micrometer), then the design of the optical system is complete. 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 refers to the light emitted from the edge position of the virtual image.

[0099] Fig.18 The field curvature diagram and distortion diagram of the projection device provided in some embodiments of the present disclosure are as follows. Field curvature is also called "field curvature". When the lens 50 has 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. In this way, the entire image plane cannot be seen clearly at the same time during microscopic examination, which makes imaging difficult. Among them, the maximum field of view of the projection device in the embodiment of the present disclosure is 78.526mm, the sagittal field curvature is 5.8217mm, and the meridian field curvature is 5.3756mm. The dispersion of the projection device for RGB three colors is small; the maximum distortion is 3.0612%, and the barrel distortion and pincushion distortion of the picture are small.

[0100] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A projection device, characterized in that: include: 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 a plurality of corresponding second light rays emitted toward the transflective mirror, and at least part of the second light rays are reflected by the transflective mirror to 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 whose divergence angle is greater than the 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, characterized in that: 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 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.

3. The projection device according to claim 1, characterized in that: The projection device further comprises a lens, which is arranged 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 a convex surface, and the other is a concave surface.

4. The projection device according to claim 3, characterized in that: At least part of the outgoing light of the lens is reflected by the reflective mirror to the reflector, wherein, for a plurality of light rays emitted from the lens to the reflector, there is a first distance between the exit position of the light ray on the lens and the central axis of the lens, and there is a second distance between the incident position of the light ray 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, characterized in that: 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, characterized in that: 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, characterized in that: The reflecting surface of the reflector is mirror-symmetrical with respect to a first reference surface and a second reference surface. The first reference surface is a plane passing through the center of the reflecting surface and parallel to the light modulation component, and the second reference surface is a plane passing through the central axis of the reflecting surface and perpendicular to the first reference surface.

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

9. The projection device according to claim 8, characterized in that: 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 transflector and the first intersection point, and the fourth distance is greater than the third distance.

10. The projection device according to claim 3, characterized in that: 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, characterized in that: The light emitting area of ​​the optical modulation component is rectangular, a first light shading layer in a ring shape is arranged on the lens, the inner edge of the ring shape is rectangular, and the inner edge length of the ring shape is 2*(tanθ*h+L / 2), the inner edge width of the ring shape is 2*(tanθ*h+W / 2), 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 and the lens.

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

13. The projection device according to any one of claims 1 to 12, characterized in that: The projection device also includes: 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 transflector away from the light modulation component; A 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, characterized in that: The polarizer and the second quarter-wave plate both cover at least the effective area of ​​the transflector, the light-emitting area of ​​the light modulation component is a rectangle, 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 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, characterized in that: 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, characterized in that: The transflective mirror comprises an effective area and an ineffective area surrounding the effective area, wherein the effective area is an irradiation area of ​​the reflected light of the reflector on the transflective mirror; Wherein, a second light-shielding layer is arranged on a 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, characterized in that: 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