Prism and projection system with prism

Abstract

The present invention provides a prism and a projection system with the prism, wherein the projection system includes a light source, at least one prism, an imaging element and a projection lens, wherein the light emitted by the light source is refracted to the imaging element through the prism, and an imaging light with image information is reflected by the imaging element, wherein the prism has a light incident surface, a light exit surface and a total reflection surface, and at least one of the planes among the light incident surface, the light exit surface and the total reflection surface of the prism is an inclined surface with a preset inclination angle, so that the imaging light reflected by the imaging element is obliquely projected to the projection lens along a specific deflection angle through the prism, and forms the target imaging surface with the set inclination angle through the projection lens.

Description

Technical Field

[0001] The present invention relates to the technical field of optical projection, and in particular to a prism and a projection system with the prism. Background Art

[0002] As vehicle lighting functions become more and more diverse, more and more automotive manufacturers are developing new projection technologies. Among them, the extremely high resolution of digital projection technology based on DMD (Digital Micromirror Device) is favored by OEMs. Using existing dynamic projection design solutions, such as DLP (Digital Light Processing) projection systems based on DMD technology, a prism solution is usually used in the entire optical path to achieve the connection between the illumination optical path and the projection optical path; then the DMD image is projected onto the target imaging surface in the distance through the projection lens.

[0003] The projection system of the prior art also has at least one of the following defects: (1) The application scenario of the DMD system of the prior art is the vertical target imaging surface, and the MTF (modulation transfer function) performance after the system optimization can easily achieve the consistency of the resolution of each area of ​​the image surface. However, in vehicle-mounted projection, the projected target imaging surface is often a scene of inclined projection such as the ground. In this case, the consistency of the clarity of each image point on the inclined target imaging surface cannot be guaranteed. (2) In the scenario of inclined projection, in order to ensure the clarity of each part of the target imaging surface, it is necessary to manually adjust the tilt angle of the DMD and the eccentric tilt of the DMD at the same time, which increases the complexity and difficulty of the system. (3) In the conventional inclined projection scenario, in order to ensure the clarity of the inclined projection, it is necessary to add additional structures. The projection system has the problems of large size and heavy weight. Therefore, in order to ensure sufficient adjustment space, the structure needs to leave enough space for adjustment, which increases the complexity of the system. (4) Due to the insufficient image quality clarity of the edge field of view of the target imaging surface during inclined projection, DMD cannot be promoted on a large scale in such applications. (5) If other optical measures are introduced to correct the image quality of the target imaging surface, it will often increase system cost and design difficulty. Summary of the invention

[0004] A major advantage of the present invention is that it provides a prism and a projection system with a prism, wherein an imaging unit of the projection system generates an imaging light, which is refracted by the prism and projected onto a target imaging surface, and the prism has at least one inclined surface to obtain a focal plane with a consistent optical path difference, that is, an equipotential surface, so that the equipotential surface has an outgoing light beam with a specific inclination angle.

[0005] Another advantage of the present invention is that it provides a prism and a projection system with a prism, and improves the MTF difference caused by the different projection positions of different areas of the target imaging surface through the inclined surface of the prism, thereby achieving consistent resolution of each image point on the inclined target imaging surface and improving uniformity.

[0006] Another advantage of the present invention is to provide a prism and a projection system with the prism, wherein the projection system can achieve position change of the imaging surface without adding additional components, and the system will not increase the volume and weight of the original system.

[0007] Another advantage of the present invention is to provide a prism and a projection system with the prism, wherein the MTF difference caused by different projection positions is compensated by tilting the total reflection surface of the prism, thereby improving the image clarity of the edge field of view of the target imaging surface.

[0008] Another advantage of the present invention is to provide a prism and a projection system with the prism, wherein the entire assembly structure does not change. In addition, during DMD adjustment, only the eccentricity of the DMD needs to be adjusted, and the tilt of the DMD does not need to be considered, thereby reducing the difficulty of adjustment.

[0009] Another advantage of the present invention is to provide a prism and a projection system with the prism, wherein the prism is an integrated structure with a simple structure and no additional cost.

[0010] Another advantage of the present invention is to provide a prism and a projection system with the prism, wherein the prism has a light incident surface, a total reflection surface and a light exit surface, wherein at least one plane among the light incident surface, the light exit surface and the total reflection surface is the inclined surface. In other words, the MTF is compensated by the inclination of different surfaces, providing design diversity.

[0011] According to one aspect of the present invention, a prism of the present invention that can achieve the above-mentioned purpose and other purposes and advantages is suitable for a projection system, wherein the projection system includes a light source, an imaging element and a projection lens, wherein the light emitted by the light source is refracted to the imaging element through the prism, and the imaging element reflects an imaging light with image information, wherein the prism has:

[0012] a light incident surface, adapted to be disposed face to face with the imaging element;

[0013] a light emitting surface, adapted to be disposed face to face with the projection lens; and

[0014] A total reflection surface, wherein the total reflection surface corresponds to the light incident surface and the light exit surface of the prism, the light incident surface, the light exit surface and the total reflection surface of the prism are planes formed on the prism, and at least one of the light incident surface, the light exit surface and the total reflection surface of the prism is an inclined surface with a preset inclination angle, so that the imaging light reflected by the imaging element is projected along a specific deflection angle δ through the prism to the projection lens, and the target imaging surface with the set inclination angle is formed through the projection lens.

[0015] According to an embodiment of the present invention, the total reflection surface of the prism is the inclined surface with a preset inclination angle θ1, and the light incident surface and the light emitting surface of the prism are right-angled surfaces perpendicular to each other.

[0016] According to one embodiment of the present invention, the inclination angle θ1 of the total reflection surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ1, where δ1 satisfies δ1=arcsin(n·sin2θ1).

[0017] According to an embodiment of the present invention, the light emitting surface of the prism is the inclined surface having a preset inclination angle θ2.

[0018] According to one embodiment of the present invention, the inclination angle θ2 of the light emitting surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ2, where δ2 satisfies δ2=arcsin(n·sinθ2)-θ2.

[0019] According to an embodiment of the present invention, the light incident surface of the prism is the inclined surface having a preset inclination angle θ3.

[0020] According to one embodiment of the present invention, the inclination angle θ3 of the light incident surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ3, where δ3 satisfies

[0021] According to an embodiment of the present invention, the light incident surface of the prism is the inclined surface having a preset inclination angle θ4, and the total reflection surface of the prism is the inclined surface having a preset inclination angle θ5.

[0022] According to one embodiment of the present invention, the tilt angle θ4 of the light incident surface of the prism satisfies: The inclination angle θ5 of the total reflection surface satisfies: Where n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ4, where δ4 satisfies:

[0023] According to another aspect of the present invention, the present invention further provides a projection system, comprising:

[0024] a light source;

[0025] At least one prism;

[0026] an imaging element, wherein the light emitted by the light source is refracted by the prism to the imaging element, and the imaging element reflects an imaging light with image information; and

[0027] a projection lens, which is arranged in the light emitting direction of the prism;

[0028] In which, the prism has a light incident surface, a light exit surface and a total reflection surface, wherein the light incident surface of the prism is a plane arranged face to face with the imaging element, the light exit surface of the prism is a plane arranged face to face with the projection lens, the total reflection surface is a plane corresponding to the light incident surface and the light exit surface of the prism, and at least one of the light incident surface, the light exit surface and the total reflection surface of the prism is an inclined surface with a preset inclination angle, so that the imaging light reflected by the imaging element is projected obliquely along a specific deflection angle δ through the prism to the projection lens, and forms the target imaging surface with a set inclination angle through the projection lens.

[0029] According to an embodiment of the present invention, the total reflection surface of the prism is the inclined surface with a preset inclination angle θ1, and the light incident surface and the light emitting surface of the prism are right-angled surfaces perpendicular to each other.

[0030] According to one embodiment of the present invention, the inclination angle θ1 of the total reflection surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ1, where δ1 satisfies δ1=arcsin(n·sin2θ1).

[0031] According to an embodiment of the present invention, the light emitting surface of the prism is the inclined surface having a preset inclination angle θ2.

[0032] According to one embodiment of the present invention, the inclination angle θ2 of the light emitting surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ2, where δ2 satisfies δ2=arcsin(n·sinθ2)-θ2.

[0033] According to an embodiment of the present invention, the light incident surface of the prism is the inclined surface having a preset inclination angle θ3.

[0034] According to one embodiment of the present invention, the inclination angle θ3 of the light incident surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ3, where δ3 satisfies

[0035] According to an embodiment of the present invention, the light incident surface of the prism is the inclined surface having a preset inclination angle θ4, and the total reflection surface of the prism is the inclined surface having a preset inclination angle θ5.

[0036] According to one embodiment of the present invention, the tilt angle θ4 of the light incident surface of the prism satisfies: The inclination angle θ5 of the total reflection surface satisfies: Where n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ4, where δ4 satisfies:

[0037] According to one embodiment of the present invention, the inclination angle of the target imaging surface formed by the projection lens is and the output beam deflection angle δ satisfies

[0038] According to one embodiment of the present invention, it further includes an optical shaping system, wherein the optical shaping system is located between the light source and the prism, and the optical shaping system includes at least one collimating lens, at least one fly-eye lens, and at least one relay lens, wherein the light emitted by the light source is collimated by the collimating lens, enters the fly-eye lens, is beam shaped by the fly-eye lens, and then reaches the prism through the at least one relay lens.

[0039] According to one embodiment of the present invention, the projection lens satisfies the object-image conjugate relationship L′ is the image distance of the image plane relative to the projection lens, f is the equivalent focal length of the projection lens; and L is the object distance of the light emitting surface of the prism relative to the projection lens.

[0040] According to an embodiment of the present invention, the light emitting surface of the prism is located between one focal length and two focal lengths of the projection lens.

[0041] Further objects and advantages of the present invention will be fully apparent from an understanding of the following description and the accompanying drawings.

[0042] These and other objects, features and advantages of the present invention will be more fully understood from the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 2 is a schematic diagram of an inclined projection of a projection system according to a first preferred embodiment of the present invention.

[0044] Figure 2 Schematic diagram of the optical path of the projection system according to the first preferred embodiment of the present invention.

[0045] Figure 3 Schematic diagram of the structure of a prism of the projection system according to the first preferred embodiment of the present invention.

[0046] Figure 4 Schematic diagram of the optical path of the prism of the projection system according to the first preferred embodiment of the present invention.

[0047] Figure 5 Schematic diagram of the structure of a prism of the projection system according to the second preferred embodiment of the present invention.

[0048] Figure 6 Schematic diagram of the optical path of the prism of the projection system according to the second preferred embodiment of the present invention.

[0049] Figure 7 is a schematic structural diagram of a prism of the projection system according to the third preferred embodiment of the present invention.

[0050] Figure 8 Schematic diagram of the optical path of the prism of the projection system according to the third preferred embodiment of the present invention.

[0051] Fig. 9 is a schematic structural diagram of a prism of the projection system according to the fourth preferred embodiment of the present invention.

[0052] Fig.10 Schematic diagram of the optical path of the prism of the projection system according to the fourth preferred embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0054] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0055] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0056] Referring to the accompanying drawings of the present invention Figures 1 to 4 As shown, a projection system according to the first preferred embodiment of the present invention is explained in the following description. The projection system includes at least one light source 10, an optical shaping system 20 along the emission direction of the light source, at least one prism 30, an imaging element 40, and a projection lens 50, wherein the light emitted by the light source 10 reaches the prism 30 through the optical shaping system 20, and the light is refracted to the imaging element 40 through the prism 30, and forms an illumination spot on the imaging element 40. The imaging element 40 reflects to form an imaging light with image information to the prism 30, wherein the imaging light is totally reflected to the projection lens 50 through the prism 30, and forms a target imaging surface 100 along the emission direction of the light from the projection lens 50. It is worth mentioning that in this preferred embodiment of the present invention, the projection system can be but is not limited to a DLP projection system, such as dynamic projection of headlights, HUD, etc.

[0057] In this preferred embodiment of the present invention, without the need to assemble other components, the target imaging plane 100 formed by the projection system is tilted in a specific direction, such as tilted to the right, tilted to the left, tilted forward, tilted backward, and tilted in any other direction in space, only through the optical structural characteristics of the prism, so as to adapt to projection planes of different planes, such as inclined ground or glass surface. In addition, in this preferred embodiment of the present invention, the prism 30 compensates for the difference in modulation transfer function (MTF) caused by different projection positions, thereby improving the image plane clarity of the edge field of view of the target imaging plane 100.

[0058] The prism 30 has a light incident surface 31, a light exit surface 32, and a total reflection surface 33, wherein the light incident surface 31 of the prism 30 is a plane disposed face-to-face with the imaging element 40, the light exit surface 32 of the prism 30 is a plane disposed face-to-face with the projection lens 50, and the total reflection surface 33 is a plane corresponding to the light incident surface 31 and the light exit surface 32 of the prism 30. The imaging light reflected by the imaging element 40 is incident on the total reflection surface 33 through the light incident surface 31 of the prism 30, and is reflected by the total reflection surface 33 to the light exit surface 32, and then is emitted to the projection lens 50 through the light exit surface 32. At least one of the light incident surface 31, the light emitting surface 32 and the total reflection surface 33 of the prism 30 is an inclined surface S with a preset inclination angle θ, so that the imaging light reflected by the imaging element 40 is refracted and / or reflected by the inclined surface S, and is tilted along a specific deflection angle δ to the projection lens 50, and passes through the projection lens 50 to form a light beam with a preset inclination angle. It is worth mentioning that in the present invention, the set inclination angle of the target imaging surface 100 is The angle direction of depends on the angle direction of the preset inclination angle θ of the inclined surface S.

[0059] In other words, in this preferred embodiment of the present invention, based on the tilt angle of the target imaging plane 100 required by the projection system, the MTF difference caused by the different projection positions of different areas of the target imaging plane 100 is compensated or corrected by the at least one tilted surface S preset in the prism 30, so as to achieve the resolution consistency of each image point of the tilted target imaging plane 100. Therefore, in this preferred embodiment of the present invention, there is no need to add extra optical elements or other devices to compensate for the MTF difference caused by the incorrect projection position, and the overall volume and weight of the system will not be increased.

[0060] like Figure 3 and Figure 4 As shown, in this preferred embodiment of the present invention, the total reflection surface 33 of the prism 30 is the inclined surface S1 with a preset inclination angle θ1, the light incident surface 31 and the light exit surface 32 of the prism 30 are right-angled surfaces, and the plane where the light incident surface 31 is located and the plane where the light exit surface 32 is located are perpendicular to the line L. Preferably, in this preferred embodiment of the present invention, the light incident surface 31 of the prism 30 is positively opposite to the imaging element 40, and the light exit surface 32 of the prism 30 is positively opposite to the projection lens 50. The imaging light reflected by the imaging element 40 is vertically incident on the light incident surface 31 of the prism 30, and is reflected by the total reflection surface 33 of the prism 30 to the light exit surface 32 of the prism 30. The imaging light is obliquely projected to the projection lens 50 along a specific deflection angle δ1, and passes through the projection lens 50 to form a projection lens 50 with a set inclination angle. The target imaging surface 100.

[0061] In detail, the prism 30 further has a front face 301 and a rear face 302 which is directly opposite to the front face 301, wherein the front face 301 and the rear face 302 of the prism 30 are formed at the ends of the prism 30, and intersect with the light incident surface 31, the light exit surface 32 and the total reflection surface 33. In this preferred embodiment of the present invention, a virtual plane 330 is provided, wherein the virtual plane 330 intersects with the total reflection surface 33 of the prism 30, and the virtual plane 330 is parallel to the line L, wherein the preset inclination angle θ1 of the total reflection surface 33 of the prism 30 is the angle between the virtual plane and the total reflection surface 33.

[0062] like Figure 3 and Figure 4 As shown, as an example, the virtual plane 330 and the total reflection surface 33 of the prism 30 are collinear with the rear end face 302 of the prism 30, and the total reflection surface 33 of the prism 30 extends obliquely inward from the rear end face 302 of the prism 30 to the front end face 301 of the prism 30. The imaging light emitted by the imaging element 40 is obliquely projected to the projection lens 50 along the specific deflection angle δ1 through the prism 30, and then projected to the target imaging surface 100 through the projection lens 50, wherein the target imaging surface 100 is offset to the right along the vertical plane at an angle δ1. That is, the prism 30 generates a horizontal rightward tilt angle.

[0063] It is worth mentioning that Figure 3 and Figure 4The preset tilt angle θ1 of the total reflection surface 33 of the prism 30 shown here is only exemplary and not limiting. Therefore, in other optional embodiments of the present invention, the preset tilt angle θ1 of the total reflection surface 33 of the prism 30 may also be oriented in other directions, so that the image projected onto the target imaging surface 100 generates a tilt angle in the horizontal or vertical direction to the left, right, forward, backward, and any other direction in space.

[0064] Preferably, in this preferred embodiment of the present invention, the prism 30 is an integrated structure, that is, the inclined surface S1 of the prism 30 is integrally formed on the surface of the prism 30, so no additional cost is added, thereby providing an economical and effective technical solution for the present invention.

[0065] It is worth mentioning that the light beam is incident on the total reflection surface 33 of the prism 30 and is totally reflected on the total reflection surface. α is the incident angle of the light beam on the inclined surface of the prism, and n is the refractive index of the prism material. The light beam is totally reflected by the total reflection surface 33 of the prism 30, and the light path is folded to obtain an outgoing light with a specific tilt angle on the isophase surface. It is worth mentioning that, through the effect of the tilt surface S1 of the prism 30, the system volume can be miniaturized; and the relay image incident on the subsequent projection lens 50 can have a specific tilt angle.

[0066] In this preferred embodiment of the present invention, the inclination angle θ1 satisfies: Wherein 1.4≤n≤1.9. The deflection angle δ1 of the light beam emitted by the prism 30 satisfies δ1=arcsin(n·sin2θ1).

[0067] Preferably, in this preferred embodiment of the present invention, 0≤δ1≤12°. It is worth mentioning that in this preferred embodiment of the present invention, the inclination angle of the total reflection surface 33 of the prism 30 that meets the optical formula can realize the total reflection of the light beam on the total reflection surface 33 of the prism 30, and obtain the output light with a specific inclination angle. By setting the inclination of the total reflection surface of the prism 30, the image emitted by the imaging element 40 is converted into an inclined image plane, thereby compensating for the MTF difference caused by different projection positions and improving the clarity of the edge field of view.

[0068] In the preferred embodiment of the present invention, the target imaging plane 100 is set as an inclined plane, and the inclination angle with the vertical plane is The prism output beam deflection angle δ1 satisfies Preferred range

[0069] It can be understood that the inclination angle of the target imaging plane 100 that meets the above conditional expression is the same as the angle of the image plane emitted by the system, and an image plane with good MTF in each area is obtained, thereby achieving high-resolution output of the image plane in an inclined projection state.

[0070] The target imaging plane 100 and the prism light beam exiting image plane satisfy the object-image conjugate relationship for the projection lens 50. L′ is the image distance of the image plane relative to the projection lens 50 , f is the equivalent focal length of the projection lens 50 ; and L is the object distance of the light emitting surface 32 of the prism 30 relative to the projection lens 50 .

[0071] It is worth mentioning that the target imaging plane position that meets the above conditional expression is the same as the focusing position of the best image plane emitted by the system, so that an image plane with good MTF in each area is obtained, and a high-resolution output of the image plane under inclined projection is achieved.

[0072] In this preferred embodiment of the present invention, the light emitting surface 32 of the prism 30 is located between one times the focal length and two times the focal length of the projection lens 50, that is, it satisfies the following condition: f≤L≤2f, so as to meet the pixel magnification condition. The light beam emitted by the prism 30 enters the projection lens 50 to realize pixel magnification, so as to ensure that the system obtains an effectively magnified image.

[0073] Preferably, in this preferred embodiment of the present invention, the prism 30 is integrally formed without the need to add other optical elements for use, and no additional variables are introduced. Due to the effect of the inclined surface S1 of the prism 30, that is, the total reflection surface 33, the change of the back focus of the system is achieved, so the position of the imaging element 40 remains unchanged. During the adjustment process, only the eccentricity tolerance of the imaging element 40 needs to be considered, which greatly reduces the difficulty of adjustment; it does not increase the complexity of the system, nor does it increase the volume and weight of the system. It is worth mentioning that in this preferred embodiment of the present invention, the inclination angle of the target imaging surface 100 should be greater than or equal to 5°.

[0074] like Figure 1 and Figure 2 As shown, the optical shaping system 20 is disposed between the light source 10 and the prism 30, and the optical shaping system 20 shapes the light emitted by the light source 10 and the light is incident from the total reflection surface 33 of the prism 30. Preferably, in this preferred embodiment of the present invention, the light source 10 can be, but not limited to, an LED light source, an LD light source, and a laser light source. It is worth mentioning that in this preferred embodiment of the present invention, the light source 10 can be, but not limited to, white light or monochromatic light.

[0075] The optical shaping system 20 includes at least one collimating lens 21, at least one fly-eye lens 22, and at least one relay lens 23, wherein the light emitted by the light source 10 is collimated by the collimating lens 21, enters the fly-eye lens 22, is beam shaped by the fly-eye lens 22, and then passes through the at least one relay lens 23 to reach the prism 30.

[0076] Referring to the accompanying drawings of the present invention Figure 5 and Figure 6 As shown, a prism 30A of a projection system according to a second preferred embodiment of the present invention is explained in the following description. The prism 30A has a light incident surface 31A, a light exit surface 32A and a total reflection surface 33A, wherein the light incident surface 31A of the prism 30A is a plane disposed face to face with the imaging element 40, the light exit surface 32A of the prism 30A is a plane disposed face to face with the projection lens 50, and the total reflection surface 33A is a plane corresponding to the light incident surface 31A and the light exit surface 32A of the prism 30A. The imaging light formed by reflection of the imaging element 40 is incident on the total reflection surface 33A through the light incident surface 31A of the prism 30A, and is reflected by the total reflection surface 33A to the light exit surface 32A, and then is emitted to the projection lens 50 through the light exit surface 32A. Similar to the first preferred embodiment described above, in this preferred embodiment of the present invention, based on the tilt angle of the target imaging plane 100 required by the projection system, the MTF difference caused by the different projection positions of different areas of the target imaging plane 100 is compensated or corrected by the at least one inclined surface S2 preset in the prism 30A, so as to achieve the resolution consistency of each image point of the tilted target imaging plane 100.

[0077] Different from the first preferred embodiment described above, in this preferred embodiment of the present invention, the light emitting surface 32A is the inclined surface. Figure 5 and Figure 6 As shown, in this preferred embodiment of the present invention, the light exit surface 32A of the prism 30A is the inclined surface S2 with a preset inclination angle θ2. Preferably, in this preferred embodiment of the present invention, the light incident surface 31A of the prism 30A is positively opposite to the imaging element 40, and the light exit surface 32A of the prism 30A corresponds to the projection lens 50. The imaging light reflected by the imaging element 40 is vertically incident on the light incident surface 31A of the prism 30A, and is reflected by the total reflection surface 33A of the prism 30A to the light exit surface 32A of the prism 30A. The imaging light is obliquely projected to the projection lens 50 along a specific deflection angle δ2, and is formed through the projection lens 50 to have a set inclination angle. The target imaging surface 100.

[0078] In this preferred embodiment of the present invention, a virtual plane 320A is set, wherein the virtual plane 320A intersects with the light exit surface 32A of the prism 30A, and the virtual plane 320A is perpendicular to the light incident surface 31A, that is, the virtual plane 320A is a vertical plane located on the same side of the light exit surface 32A and perpendicular to the light incident surface 31A, wherein the preset inclination angle θ2 of the light exit surface 32A of the prism 30A is the angle between the virtual plane 320A and the light exit surface 32A.

[0079] like Figure 5 and Figure 6 As shown, as an example, the virtual plane 320A and the light exit surface 32A of the prism 30A are colinear with the rear end surface 302A of the prism 30A, and the light exit surface 32A of the prism 30A extends obliquely inward from the rear end surface 302A of the prism 30A to the front end surface 301A of the prism 30A. The imaging light emitted by the imaging element 40 is obliquely projected to the projection lens 50 along the specific deflection angle δ2 through the prism 30A, and then projected to the target imaging surface 100 through the projection lens 50, wherein the target imaging surface 100 is offset to the right along the vertical plane at an angle δ2. That is, the prism 30A generates a horizontal rightward tilt angle.

[0080] It is worth mentioning that Figure 5 and Figure 6 The preset tilt angle θ2 of the light emitting surface 32A of the prism 30A shown here is only exemplary and not limiting. Therefore, in other optional embodiments of the present invention, the preset tilt angle θ2 of the light emitting surface 32A of the prism 30A may also be oriented in other directions, so that the light projected onto the target imaging surface 100 is tilted to the left, right, forward, backward, and any other direction in space along the horizontal or vertical direction.

[0081] In this preferred embodiment of the present invention, the inclination angle θ2 satisfies: Wherein 1.4≤n≤1.9. The deflection angle δ2 of the light beam emitted by the prism 30A satisfies δ2=arcsin(n·sinθ2)-θ2.

[0082] Preferably, in this preferred embodiment of the present invention, 0≤δ2≤12°. It is worth mentioning that in this preferred embodiment of the present invention, the inclination angle of the light emitting surface 32A of the prism 30A that satisfies the optical formula can realize that the light beam is emitted from the light emitting surface 32A of the prism 30A at a specific inclination angle. By setting the prism 30A to convert the image emitted by the imaging element 40 into an inclined image plane, the MTF difference caused by different projection positions is compensated, and the clarity of the edge field of view is improved.

[0083] Referring to the accompanying drawings of the present invention Figure 7 and Figure 8 As shown, a prism 30B of a projection system according to the third preferred embodiment of the present invention is explained in the following description. The prism 30B has a light incident surface 31B, a light exit surface 32B and a total reflection surface 33B, wherein the light incident surface 31B of the prism 30B is a plane disposed face to face with the imaging element 40, the light exit surface 32B of the prism 30B is a plane disposed face to face with the projection lens 50, and the total reflection surface 33B is a plane corresponding to the light incident surface 31B and the light exit surface 32B of the prism 30B. The imaging light formed by the reflection of the imaging element 40 is incident on the total reflection surface 33B through the light incident surface 31B of the prism 30B, and is reflected by the total reflection surface 33B to the light exit surface 32B, and then is emitted to the projection lens 50 through the light exit surface 32B. Similar to the first preferred embodiment described above, in this preferred embodiment of the present invention, based on the tilt angle of the target imaging plane 100 required by the projection system, the MTF difference caused by the different projection positions of different areas of the target imaging plane 100 is compensated or corrected by the at least one inclined surface S3 preset in the prism 30B, so as to achieve the resolution consistency of each image point of the tilted target imaging plane 100.

[0084] Different from the first preferred embodiment described above, in this preferred embodiment of the present invention, the light incident surface 31B is the inclined surface. Figure 7 and Figure 8As shown, in this preferred embodiment of the present invention, the light incident surface 31B of the prism 30B is the inclined surface S3 with a preset inclination angle θ3. Preferably, in this preferred embodiment of the present invention, the light incident surface 31B of the prism 30B corresponds to the imaging element 40, and the light exit surface 32B of the prism 30B is positively opposite to the projection lens 50. The imaging light reflected by the imaging element 40 is vertically incident on the light incident surface 31B of the prism 30B, and is reflected by the total reflection surface 33B of the prism 30B to the light exit surface 32B of the prism 30B. The imaging light is obliquely projected to the projection lens 50 along a specific deflection angle δ3, and passes through the projection lens 50 to form a projection lens 50 with a set inclination angle. The target imaging surface 100.

[0085] In this preferred embodiment of the present invention, a virtual plane 310B is set, wherein the virtual plane 310B intersects with the light incident surface 31B of the prism 30B, and the virtual plane 310B is perpendicular to the light exit surface 32B, that is, the virtual plane 310B is a vertical plane located on the same side of the light incident surface 31B and perpendicular to the light exit surface 32B, wherein the preset inclination angle θ3 of the light incident surface 31B of the prism 30B is the angle between the virtual plane 310B and the light incident surface 31B.

[0086] like Figure 7 and Figure 8 As shown, as an example, the virtual plane 310B and the light incident surface 31B of the prism 30B are colinear with the rear end surface 302B of the prism 30B, and the light incident surface 31B of the prism 30B extends obliquely inward from the rear end surface 302B of the prism 30B to the front end surface 301B of the prism 30B. The imaging light emitted by the imaging element 40 is obliquely projected to the projection lens 50 along the specific deflection angle δ3 through the prism 30B, and then projected to the target imaging surface 100 through the projection lens 50, wherein the target imaging surface 100 is offset to the right along the vertical plane at an angle δ3. That is, the prism 30B generates a horizontal rightward tilt angle.

[0087] It is worth mentioning that Figure 7 and Figure 8The preset tilt angle θ3 of the light incident surface 31B of the prism 30B shown here is only exemplary and not limiting. Therefore, in other optional embodiments of the present invention, the preset tilt angle θ3 of the light incident surface 31B of the prism 30B can also be oriented in other directions, so that the light projected onto the target imaging surface 100 is tilted to the left, right, forward, backward, and any other direction in space along the horizontal or vertical direction.

[0088] In this preferred embodiment of the present invention, the inclination angle θ3 satisfies: Where 1.4≤n≤1.9. The deflection angle δ3 of the light beam emitted by the prism 30B satisfies

[0089] Preferably, in this preferred embodiment of the present invention, 0≤δ3≤12°. It is worth mentioning that in this preferred embodiment of the present invention, the inclination angle of the light incident surface 31B of the prism 30B that satisfies the optical formula can realize that the light beam is emitted at a specific inclination angle at the light incident surface 31B of the prism 30B. By setting the prism 30B to convert the image emitted by the imaging element 40 into an inclined image plane, the MTF difference caused by different projection positions is compensated, and the clarity of the edge field of view is improved.

[0090] Referring to the accompanying drawings of the present invention Fig. 9 and Fig.10 As shown, a prism 30C of a projection system according to a fourth preferred embodiment of the present invention is explained in the following description. The prism 30C has a light incident surface 31C, a light exit surface 32C and a total reflection surface 33C, wherein the light incident surface 31C of the prism 30C is a plane disposed face to face with the imaging element 40, the light exit surface 32C of the prism 30C is a plane disposed face to face with the projection lens 50, and the total reflection surface 33C is a plane corresponding to the light incident surface 31C and the light exit surface 32C of the prism 30C. The imaging light formed by the reflection of the imaging element 40 is incident on the total reflection surface 33C through the light incident surface 31C of the prism 30C, and is reflected by the total reflection surface 33C to the light exit surface 32C, and then is emitted to the projection lens 50 through the light exit surface 32C. Similar to the first preferred embodiment described above, in this preferred embodiment of the present invention, based on the tilt angle of the target imaging plane 100 required by the projection system, an inclined surface S4 and an inclined surface S5 preset in the prism 30C are used to compensate or correct the MTF differences caused by the different projection positions of different areas of the target imaging plane 100, so as to achieve resolution consistency of each image point of the tilted target imaging plane 100.

[0091] Different from the first preferred embodiment described above, in this preferred embodiment of the present invention, the light incident surface 31C is the inclined surface S4, the total reflection surface 33C is the inclined surface S5, and the light exit surface 32C is a right-angle surface. Fig. 9 and Fig.10 As shown, in this preferred embodiment of the present invention, the light incident surface 31C of the prism 30C is the inclined surface S4 having a preset inclination angle θ4, and the total reflection surface 33C of the prism 30C is the inclined surface S5 having a preset inclination angle θ5. Preferably, in this preferred embodiment of the present invention, the light incident surface 31C of the prism 30C corresponds to the imaging element 40, and the light exit surface 32C of the prism 30C is positively opposite to the projection lens 50. The imaging light reflected by the imaging element 40 is vertically incident on the light incident surface 31C of the prism 30C, is reflected by the total reflection surface 33C of the prism 30C to the light exit surface 32C of the prism 30C, and is obliquely projected to the projection lens 50 along a specific deflection angle δ4, and is formed through the projection lens 50 to have a set inclination angle. The target imaging surface 100.

[0092] In this preferred embodiment of the present invention, a virtual plane 310C is set, wherein the virtual plane 310C intersects with the light incident surface 31C of the prism 30C, and the virtual plane 310C is perpendicular to the light exit surface 32C, that is, the virtual plane 310C is a vertical plane located on the same side of the light incident surface 31C and perpendicular to the light exit surface 32C, wherein the preset inclination angle θ4 of the light incident surface 31C of the prism 30C is the angle between the virtual plane 310C and the light incident surface 31C. A virtual plane 330C is set, wherein the virtual plane 330C intersects with the total reflection surface 33C of the prism 30C, and the virtual plane 330C is parallel to the line L, wherein the preset inclination angle θ5 of the total reflection surface 33C of the prism 30C is the angle between the virtual plane and the total reflection surface 33C.

[0093] like Fig. 9 and Fig.10As shown, as an example, the virtual plane 310C and the light incident surface 31C of the prism 30C are colinear with the rear end surface 302C of the prism 30C, and the light incident surface 31C of the prism 30C extends obliquely inward from the rear end surface 302C of the prism 30C to the front end surface 301C of the prism 30C. The imaging light emitted by the imaging element 40 is projected to the projection lens 50 along the specific deflection tilt through the prism 30C, and then projected to the target imaging surface 100 through the projection lens 50, wherein the target imaging surface 100 is offset to the right along the vertical plane, that is, the prism 30C generates a horizontal rightward tilt angle. Also as an example, the virtual plane 330C and the total reflection surface 33C of the prism 30C are colinear with the rear end surface 302C of the prism 30C, and the total reflection surface 33C of the prism 30C extends obliquely inward from the rear end surface 302C of the prism 30C to the front end surface 301C of the prism 30C. The imaging light emitted by the imaging element 40 is projected to the projection lens 50 along the specific deflection tilt through the prism 30C, and then projected to the target imaging surface 100 through the projection lens 50, wherein the target imaging surface 100 is offset to the right along the vertical plane, that is, the horizontal rightward tilt angle is generated by the prism 30C.

[0094] It is worth mentioning that Fig. 9 and Fig.10 The tilt direction of the total reflection surface 33C of the prism 30C and the tilt direction of the light incident surface 31C of the prism 30C shown here are only exemplary and not limiting. Therefore, in other optional embodiments of the present invention, the preset tilt angle θ4 of the light incident surface 31C of the prism 30C and the preset tilt angle θ5 of the total reflection surface 33C can also be oriented in other directions, so that the light projected onto the target imaging surface 100 is tilted to the left, right, forward, backward, and any other direction in space along the horizontal or vertical direction.

[0095] In the preferred embodiment of the present invention, the inclination angle θ4 of the light incident surface 31C satisfies: The inclination angle θ5 of the total reflection surface 33C satisfies: Where 1.4≤n≤1.9. The deflection angle δ4 of the light beam emitted by the prism 30C satisfies

[0096] Preferably, in this preferred embodiment of the present invention, 0≤δ4≤12°. It is worth mentioning that in this preferred embodiment of the present invention, the inclination angle of the light incident surface 31C of the prism 30C that satisfies the optical formula can realize that the light beam is emitted at a specific inclination angle at the light incident surface 31C of the prism 30C. By setting the prism 30C to convert the image emitted by the imaging element 40 into an inclined image plane, the MTF difference caused by different projection positions is compensated, and the clarity of the edge field of view is improved.

[0097] It should be understood by those skilled in the art that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A prism, suitable for a projection system, the projection system comprising a light source, an imaging element and a projection lens, wherein the light emitted by the light source is refracted by the prism to the imaging element, and the imaging element reflects an imaging light with image information, characterized in that: The prism has: a light incident surface, adapted to be disposed face to face with the imaging element; a light emitting surface, adapted to be disposed face to face with the projection lens; and A total reflection surface, wherein the total reflection surface corresponds to the light incident surface and the light exit surface of the prism, the light incident surface, the light exit surface and the total reflection surface of the prism are planes formed on the prism, and at least one of the light incident surface, the light exit surface and the total reflection surface of the prism is an inclined surface with a preset inclination angle, so that the imaging light reflected by the imaging element is projected along a specific deflection angle δ through the prism to the projection lens, and a target imaging surface with a set inclination angle is formed through the projection lens. 2 . The prism according to claim 1 , wherein the total reflection surface of the prism is the inclined surface having a preset inclination angle θ1 , and the light incident surface and the light emitting surface of the prism are right-angled surfaces perpendicular to each other.

3. The prism according to claim 2, wherein the inclination angle θ1 of the total reflection surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ1, where δ1 satisfies δ1=arcsin(n·sin2θ1). The prism according to claim 1 , wherein the light emitting surface of the prism is the inclined surface having a preset inclination angle θ2.

5. The prism according to claim 4, wherein the inclination angle θ2 of the light emitting surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ2, where δ2 satisfies δ2=arcsin(n·sinθ2)-θ2. The prism according to claim 1 , wherein the light incident surface of the prism is the inclined surface having a preset inclination angle θ3 .

7. The prism according to claim 6, wherein the inclination angle θ3 of the light incident surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ3, where δ3 satisfies 8 . The prism according to claim 1 , wherein the light incident surface of the prism is the inclined surface having a preset inclination angle θ4 , and the total reflection surface of the prism is the inclined surface having a preset inclination angle θ5 .

9. The prism according to claim 8, wherein the light incident surface of the prism has an inclination angle θ4 satisfying: The inclination angle θ5 of the total reflection surface satisfies: Where n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ4, where δ4 satisfies:

10. A projection system, characterized in that include: a light source; At least one prism; an imaging element, wherein the light emitted by the light source is refracted by the prism to the imaging element, and the imaging element reflects an imaging light with image information; and a projection lens, which is arranged in the light emitting direction of the prism; In which, the prism has a light incident surface, a light exit surface and a total reflection surface, wherein the light incident surface of the prism is a plane arranged face to face with the imaging element, the light exit surface of the prism is a plane arranged face to face with the projection lens, the total reflection surface is a plane corresponding to the light incident surface and the light exit surface of the prism, and at least one of the light incident surface, the light exit surface and the total reflection surface of the prism is an inclined surface with a preset inclination angle, so that the imaging light reflected by the imaging element is projected obliquely along a specific deflection angle δ through the prism to the projection lens, and forms a target imaging surface with a set inclination angle through the projection lens. 11 . The projection system according to claim 10 , wherein the total reflection surface of the prism is the inclined surface having a preset inclination angle θ1 , and the light incident surface and the light emitting surface of the prism are right-angled surfaces perpendicular to each other.

12. The projection system according to claim 11, wherein the inclination angle θ1 of the total reflection surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ1, where δ1 satisfies δ1=arcsin(n·sin2θ1). 13 . The projection system according to claim 10 , wherein the light emitting surface of the prism is the inclined surface having a preset inclination angle θ2 .

14. The projection system according to claim 13, wherein the inclination angle θ2 of the light emitting surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ2, where δ2 satisfies δ2=arcsin(n·sinθ2)-θ2. 15 . The projection system according to claim 10 , wherein the light incident surface of the prism is the inclined surface having a preset inclination angle θ3 .

16. The projection system according to claim 15, wherein the inclination angle θ3 of the light incident surface of the prism satisfies: n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ3, where δ3 satisfies 17 . The projection system according to claim 10 , wherein the light incident surface of the prism is the inclined surface having a preset inclination angle θ4 , and the total reflection surface of the prism is the inclined surface having a preset inclination angle θ5 .

18. The projection system according to claim 17, wherein the light incident surface of the prism has an inclination angle θ4 satisfying: The inclination angle θ5 of the total reflection surface satisfies: Where n is the refractive index of the prism material, and the deflection angle of the light beam emitted by the prism is δ4, where δ4 satisfies:

19. The projection system according to any one of claims 11 to 18, wherein the inclination angle of the target imaging surface formed by the projection lens is and the output beam deflection angle δ satisfies 20. The projection system according to claim 19, further comprising an optical shaping system, wherein the optical shaping system is located between the light source and the prism, and the optical shaping system comprises at least one collimating lens, at least one fly-eye lens, and at least one relay lens, wherein the light emitted by the light source is collimated by the collimating lens, enters the fly-eye lens, is beam shaped by the fly-eye lens, and then reaches the prism through the at least one relay lens.

21. The projection system according to claim 19, wherein the projection lens satisfies the object-image conjugate relationship L′ is the image distance of the image plane relative to the projection lens, f is the equivalent focal length of the projection lens; and L is the object distance of the light emitting surface of the prism relative to the projection lens.

22. The projection system of claim 21, wherein the light exit surface of the prism is located between one focal length and two focal lengths of the projection lens.

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