Projection system

Abstract

The application provides a projection system, comprising a light source, a condenser lens, a compound eye lens, a first lens, a polarization beam-splitting prism, an imaging lens group, a liquid crystal panel and a second lens, the projection system further has a first optical axis and a second optical axis which are perpendicular to each other, and the first optical axis and the second optical axis are respectively arranged obliquely to a beam-splitting surface of the polarization beam-splitting prism; wherein the light source, the condenser lens, the compound eye lens, the first lens and the polarization beam-splitting prism are sequentially arranged along the first optical axis; the liquid crystal panel, the imaging lens group, the polarization beam-splitting prism and the second lens are sequentially arranged along the second optical axis; the first lens has positive optical power, the second lens has positive optical power, the first lens and the second lens are both convex flat lenses, the imaging lens group comprises a third lens with negative optical power, a fourth lens with optical power and a fifth lens with positive optical power which are sequentially arranged from the polarization beam-splitting prism to the liquid crystal panel along the second optical axis, and the projection system satisfies 1.04≤f45 / fj≤2.45.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical devices, in particular to a projection system. BACKGROUND

[0002] With the continuous development of AR / VR technology, AR glasses products have appeared in technical solutions such as single reflection, Birdbath, free-form prism, and optical waveguide. Among them, the optical waveguide scheme has the advantages of small size and light weight. The projection light machine used in the optical waveguide scheme has Lcos, LED and other light machine schemes. Among them, the Lcos projection light machine takes a single crystal silicon wafer as the substrate, uses semiconductor process to manufacture a driving panel (CMOS-LCD), and coats aluminum on the transistor as a mirror to form a CMOS substrate, and then is bonded with a glass substrate containing a transparent electrode, and is encapsulated after injecting liquid crystal. When working, the light emitted by the light source irradiates onto the LCOS panel, and the liquid crystal molecules change the arrangement state after the voltage is applied, thereby modulating the phase and intensity of the reflected light. The liquid crystal modulation state of different pixels corresponds to different gray levels and color information of the image, and the modulated light is reflected into the optical projection system, and the image is projected into the optical waveguide or directly projected into the user's field of view through complex optical elements.

[0003] In the existing Lcos projection light machine, a mirror group for imaging is usually arranged on the light-emitting side of the polarization beam splitter prism. The illumination light path and the imaging light path are relatively independent, so the light propagation path is relatively long, the light loss is high in actual use, the picture brightness is low, and if a laser light source with good coherence is used, the cost is high and the power consumption is also increased accordingly, which is not conducive to improving the product's endurance. SUMMARY

[0004] One advantage of the present application is to provide a projection system that can solve the adverse effects of the large air gap in the traditional fixed-focus lens on the performance of the lens.

[0005] In one aspect, the present application provides a projection system, comprising a light source, a condenser lens, a compound eye lens, a first lens, a polarization beam splitter prism, an imaging lens group, a liquid crystal panel and a second lens, the projection system further has a first optical axis and a second optical axis perpendicular to each other, the first optical axis and the second optical axis are respectively arranged obliquely to the light splitting surface of the polarization beam splitter prism, the side away from the liquid crystal panel along the second optical axis is a first side, and the side close to the liquid crystal panel along the second optical axis is a second side; wherein:

[0006] The light source, the condenser lens, the compound eye lens, the first lens and the polarization beam splitter prism are arranged in sequence along the first optical axis;

[0007] The liquid crystal panel, the imaging lens group, the polarization beam splitter prism and the second lens are arranged in sequence along the second optical axis;

[0008] The light source is configured to emit an original light beam, the condenser lens is configured to convert the original light beam into a collimated light beam, the fly-eye lens is configured to convert the collimated light beam into a homogenized light beam, the liquid crystal panel is configured to convert the homogenized light beam into an image light beam, and the polarization beam splitter prism is configured to reflect the homogenized light beam and transmit the image light beam at the splitting surface.

[0009] The first lens has a positive focal power, and the second lens has a positive focal power.

[0010] The imaging lens group comprises, in order from the first side to the second side along the second optical axis, a third lens, a fourth lens, and a fifth lens; the third lens has a negative focal power, the first side of the third lens is concave, and the second side of the third lens is concave; the fourth lens has a focal power, the first side of the fourth lens is convex; and the fifth lens has a positive focal power, and the first side of the fifth lens is convex.

[0011] The projection system further satisfies 1.04≤f45 / fj≤2.45; where f45 is a combined focal length of the fourth lens and the fifth lens, and fj is a focal length of the condenser lens.

[0012] In some embodiments of the present application, the first lens and the second lens are glass spherical lenses, and the refractive index of the third lens among the first lens, the second lens, the third lens, the fourth lens, and the fifth lens is the largest.

[0013] In some embodiments of the present application, the condenser lens has a positive focal power, the side of the condenser lens close to the polarization beam splitter prism is convex, the side of the condenser lens close to the light source is concave, and the fly-eye lens is a plastic lens; the center thickness of the fly-eye lens on the first optical axis is greater than the center thickness of the first lens on the first optical axis.

[0014] In some embodiments of the present application, the projection system further satisfies 2.75<CTj / CT1<3.35; where CTj is the center thickness of the condenser lens on the first optical axis, and CT1 is the center thickness of the first lens on the first optical axis.

[0015] In some embodiments of the present application, the projection system further satisfies -1.11≤R1 / R5≤-0.36; where R1 is the radius of curvature of the light entrance surface of the first lens, and R5 is the radius of curvature of the first side of the third lens.

[0016] In some embodiments of the application, the projection system further satisfies: 0.9 < f1 / f45 < 1.85; where f1 is the focal length of the first lens, and f45 is the combined focal length of the fourth lens and the fifth lens.

[0017] In some embodiments of the application, the projection system further satisfies: 0.91 ≤ |f3+f4+f5| / f2 ≤ 2.25; where f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, and f2 is the focal length of the second lens.

[0018] In some embodiments of the application, the projection system further satisfies: 0.75 ≤ (CT3+CT4) / CT5 ≤ 1.25; where CT3 is the center thickness of the third lens on the second optical axis, CT4 is the center thickness of the fourth lens on the second optical axis, and CT5 is the center thickness of the fifth lens on the second optical axis.

[0019] In some embodiments of the application, the projection system further satisfies: 3.85 ≤ (T34+T45) / CT2 ≤ 4.94; where T34 is the axial distance from the second side of the third lens to the first side of the fourth lens on the second optical axis, T45 is the axial distance from the second side of the fourth lens to the first side of the fifth lens on the second optical axis, and CT2 is the center thickness of the second lens on the second optical axis.

[0020] In some embodiments of the application, the projection system further satisfies: 0.30 ≤ |(R7+R8) / (R9+R10)| ≤ 1.00; where R7 is the radius of curvature of the first side of the fourth lens, R8 is the radius of curvature of the second side of the fourth lens, R9 is the radius of curvature of the first side of the fifth lens, and R10 is the radius of curvature of the second side of the fifth lens.

[0021] In some embodiments of the application, the projection system further satisfies: -1.45 ≤ fj / f3 ≤ -0.72; where fj is the focal length of the condenser, and f3 is the focal length of the third lens.

[0022] In some embodiments of the application, the projection system further satisfies: 2.20 ≤ f5 / CT5 ≤ 8.00; where f5 is the focal length of the fifth lens, and CT5 is the center thickness of the fifth lens on the second optical axis.

[0023] In summary, in the projection system provided by the present application, the condenser, the fly-eye lens, the first lens, the polarization beam splitter prism, the imaging lens group and the liquid crystal panel constitute the illumination lens group, the imaging lens group, the polarization beam splitter prism and the second lens constitute the imaging lens group, and the illumination lens group and the lens group share some optical components: the polarization beam splitter prism and the imaging lens group; by controlling the combined focal length f45 of the fourth lens and the fifth lens and the focal length fj of the condenser to satisfy 1.04≤f45 / fj≤2.45, while controlling the distance between the condenser and the light source to be reasonable, the light is made to directly enter the imaging lens group after the first reflection, and the converging effect of the imaging lens group on the light can guide the light to the liquid crystal panel, which is beneficial to reduce the light loss and stray light problems caused by light divergence. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the projection system in Example 1 provided in this application;

[0025] Figure 2 Based on Figure 1 Provided are optical modulation function graphs of the projection system at different fields of view in the meridional direction;

[0026] Figure 3 This is a schematic diagram of the structure of the projection system in Example 2 provided in this application;

[0027] Figure 4 Based on Figure 3 Provided are optical modulation function graphs of the projection system at different fields of view in the meridional direction;

[0028] Figure 5 This is a schematic diagram of the structure of the projection system in Example 3 provided in this application;

[0029] Figure 6 Based on Figure 5 Provided are optical modulation function graphs of the projection system at different fields of view in the meridional direction;

[0030] Figure 7 Schematic diagram of the optical path of the projection system provided according to the present application. DETAILED DESCRIPTION

[0031] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0032] It should be noted that the terms first, second, third, etc. are used herein only to distinguish one feature from another, and do not denote any limitation on the features. Thus, a first lens discussed below could also be termed a second lens or a third lens, without departing from the teachings of the present application.

[0033] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0034] In this context, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If the lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The judgment of the surface shape in the paraxial region can be made in accordance with the general method in the art, for example, judging convexity or concavity by the sign of the R value (R refers to the radius of curvature in the paraxial region). In this context, on the second optical axis, the side away from the liquid crystal panel is the first side, and the side close to the liquid crystal panel is the second side. In terms of the first side, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave. In terms of the second side, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex. On the first optical axis, the side close to the light source is the light-in surface, and the side away from the light source is the light-out surface. In terms of the light-in surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave. In terms of the light-out surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0035] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. Furthermore, as used herein, the term "and / or" means "and", "or", or both, for example, "A and / or B" means "A and B", "A or B", or both "A and B". In addition, as used herein, the expression "at least one of A and B" means only A, only B, or both A and B. Furthermore, as used herein, the expression "at least one of A or B" means only A, only B, or both A and B. In addition, as used herein, the expression "one or more of A, B, and C" means only A, only B, only C, only A and B, only A and C, only B and C, or all of A and B and C. In addition, as used herein, the expression "one or more of A or B" means only A, only B, or both A and B. In addition, as used herein, the expression "one or more of A, B, or C" means only A, only B, only C, only A and B, only A and C, only B and C, or all of A and B and C. In addition, as used herein, the expression "one or more of A or B" means only A, only B, or both A and B. Furthermore, when describing embodiments of the present application, the use of "can" means "one or more embodiments of the present application". Also, the word "exemplary" is used herein to mean "an example of" or "an example". In addition, the use of "based on" means "based at least in part on".

[0036] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0037] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The following embodiments only express several embodiments of the present application, which are described in detail and specifically, but should not be construed as limiting the scope of the patent of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] According to an aspect of the present application, as shown in Figure 1 An embodiment of the present application proposes a projection system, comprising a light source, a condenser lens Ej, a compound eye lens Ef, a first lens E1, a polarization beam splitter PBS, an imaging lens group, a liquid crystal panel and a second lens E2, the projection system further has a first optical axis Z1 and a second optical axis Z2 perpendicular to each other, the first optical axis Z1 and the second optical axis Z2 are respectively arranged obliquely to the splitting surface of the polarization beam splitter PBS, the side away from the liquid crystal panel along the second optical axis Z2 is the first side, and the side close to the liquid crystal panel along the second optical axis Z2 is the second side; wherein:

[0039] The light source, the condenser lens Ej, the compound eye lens Ef, the first lens E1 and the polarization beam splitter PBS are arranged in sequence along the first optical axis Z1;

[0040] The liquid crystal panel, the imaging lens group, the polarization beam splitter PBS and the second lens E2 are arranged in sequence along the second optical axis Z2;

[0041] The light source is used to emit an original light beam, the condenser lens Ej is used to convert the original light beam into a collimated light beam, the compound eye lens Ef is used to convert the collimated light beam into a uniform light beam, the liquid crystal panel is used to convert the uniform light beam into an image light beam, and the polarization beam splitter PBS is used to reflect the uniform light beam at the splitting surface and transmit the image light beam;

[0042] The first lens E1 has a positive focal power, the second lens E2 has a positive focal power, and the first lens E1 and the second lens E2 are both convex flat lenses;

[0043] The imaging lens group comprises, in order from the first side to the second side along the second optical axis Z2, a third lens E3, a fourth lens E4 and a fifth lens E5; the third lens E3 has a negative focal power, the first side of the third lens E3 is concave, and the second side of the third lens E3 is concave; the fourth lens E4 has a focal power, the first side of the fourth lens E4 is convex; and the fifth lens E5 has a positive focal power, and the first side of the fifth lens E5 is convex.

[0044] The projection system also satisfies: 1.04≤f45 / fj≤2.45; wherein f45 is the combined focal length of the fourth lens E4 and the fifth lens E5, and fj is the focal length of the condenser lens Ej.

[0045] In the projection system provided in the present application, the condenser lens Ej, the compound eye lens Ef, the first lens E1, the polarization beam-splitting prism PBS, the imaging lens group and the liquid crystal panel constitute an illumination lens group, the imaging lens group, the polarization beam-splitting prism PBS and the second lens E2 constitute an imaging lens group, and the illumination lens group and the imaging lens group share part of the optical components: the polarization beam-splitting prism PBS and the imaging lens group satisfy 1.04≤f45 / fj≤2.45 between the combined focal length f45 of the fourth lens E4 and the fifth lens E5 and the focal length fj of the condenser lens, so that the condenser lens Ej is reasonably controlled at a distance from the light source, the light directly enters the imaging lens group after the first reflection, the converging effect of the imaging lens group can guide the light to the liquid crystal panel, and the light loss and stray light problems caused by light divergence are reduced.

[0046] According to some embodiments of the present application, the first lens E1 and the second lens E2 are glass spherical lenses, and the refractive index of the third lens E3 among the first lens E1, the second lens E2, the third lens E3, the fourth lens E4 and the fifth lens E5 is the largest.

[0047] In this way, by limiting the focal power and shape of the first lens E1 and the second lens E2 to be convex flat lenses, the illumination lens group is essentially the same as the imaging lens group except for the condenser lens Ej and the compound eye lens Ef, and the design difficulty of the compound eye lens Ef and the condenser lens Ej in the illumination lens group is reduced.

[0048] According to some embodiments of the present application, the condenser lens Ej has a positive focal power, the side of the condenser lens Ej close to the polarization beam-splitting prism PBS is convex, the side of the condenser lens Ej close to the light source is concave, and the compound eye lens Ef is a plastic lens; the central thickness of the compound eye lens Ef on the first optical axis Z1 is greater than the central thickness of the first lens E1 on the first optical axis Z1.

[0049] In this way, by designing the focal power and surface shape of the condenser lens Ej and the compound eye lens Ef in the illumination lens group, the light rays emitted by the light source tend to be parallel after passing through them, and the light intensity of light rays of different angles tends to be consistent, thereby improving the uniformity of illumination.

[0050] According to some embodiments of the present application, the projection system further satisfies: 2.75 < CTj / CT1 < 3.35; wherein CTj is the center thickness of the condenser lens Ej on the first optical axis Z1, and CT1 is the center thickness of the first lens E1 on the first optical axis Z1.

[0051] In this way, by controlling the ratio between the center thickness of the condenser lens Ej and the first lens E1 on the first optical axis Z1, the overall size of the optical system is reduced, and the optical system is made thinner and lighter.

[0052] Preferably, the projection system satisfies: 2.77 ≤ CTj / CT1 ≤ 3.33.

[0053] According to some embodiments of the present application, the projection system further satisfies: -1.11 ≤ R1 / R5 ≤ -0.36; wherein R1 is the curvature radius of the light entrance surface of the first lens E1, and R5 is the curvature radius of the first side of the third lens E3.

[0054] In this way, by controlling the ratio between the curvature radius of the first lens E1 and the curvature radius of the third lens E3, the machinability of the lens is improved, and the production cost is reduced.

[0055] According to some embodiments of the present application, the projection system further satisfies: 0.9 < f1 / f45 < 1.85; wherein f1 is the focal length of the first lens E1, and f45 is the combined focal length of the fourth lens E4 and the fifth lens E5.

[0056] In this way, by controlling the ratio between the focal length of the first lens E1 and the combined focal length of the fourth lens E4 and the fifth lens E5, the sensitivity of the entire projection system at the first lens E1, the fourth lens E4 and the fifth lens E5 is reduced, and the production yield is improved.

[0057] Preferably, the projection system satisfies: 0.92 ≤ f1 / f45 ≤ 1.84.

[0058] According to some embodiments of the present application, the projection system further satisfies: 0.91 ≤ |f3+f4+f5| / f2 ≤ 2.25; wherein f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, and f2 is the focal length of the second lens E2.

[0059] In this way, the absolute value of the ratio of the sum of the focal lengths of all the lenses in the imaging lens group to the focal length of the second lens E2 is controlled reasonably, which is beneficial to improving the illumination quality and imaging quality of the lenses on the projection system.

[0060] According to some embodiments of the present application, the projection system further satisfies: 0.75≤(CT3+CT4) / CT5≤1.25; wherein CT3 is the central thickness of the third lens E3 on the second optical axis Z2, CT4 is the central thickness of the fourth lens E4 on the second optical axis Z2, and CT5 is the central thickness of the fifth lens E5 on the second optical axis Z2.

[0061] In this way, the range of the conditional expression is controlled reasonably, the processability of the lens is improved, and the total length of the system is reduced, so that the system is thinner.

[0062] According to some embodiments of the present application, the projection system further satisfies: 3.85≤(T34+T45) / CT2≤4.94; wherein T34 is the axial distance from the second side of the third lens E3 to the first side of the fourth lens E4 on the second optical axis Z2, T45 is the axial distance from the second side of the fourth lens E4 to the first side of the fifth lens E5 on the second optical axis Z2, and CT2 is the central thickness of the second lens E2 on the second optical axis Z2.

[0063] In this way, the range of the conditional expression is controlled reasonably, so that the product does not interfere with each other between the lenses during assembly, and the processability of the product is improved.

[0064] According to some embodiments of the present application, the projection system further satisfies: 0.30≤|(R7+R8) / (R9+R10)|≤1.00; wherein R7 is the curvature radius of the first side of the fourth lens E4, R8 is the curvature radius of the second side of the fourth lens E4, R9 is the curvature radius of the first side of the fifth lens E5, and R10 is the curvature radius of the second side of the fifth lens E5.

[0065] In this way, the range of the conditional expression is controlled reasonably, the contribution of the fourth lens E4 and the fifth lens E5 to imaging is improved, the imaging performance is improved, and the processability is ensured.

[0066] According to some embodiments of the present application, the projection system further satisfies: -1.45≤fj / f3≤-0.72; wherein fj is the focal length of the condenser lens Ej, and f3 is the focal length of the third lens E3.

[0067] In this way, the range of the conditional expression is controlled reasonably, so that the light emitted by the light source tends to be parallel after passing through the condenser lens Ej, and the distance between the light source and the condenser lens Ej is controlled.

[0068] According to some embodiments of the present application, the projection system further satisfies: 2.20≤f5 / CT5≤8.00; wherein f5 is the focal length of the fifth lens E5, and CT5 is the center thickness of the fifth lens E5 on the second optical axis Z2.

[0069] In this way, the conditional range is reasonably controlled, the contribution of the fifth lens E5 to imaging is improved, the imaging performance is improved, and the processability is ensured.

[0070] Some specific but non-limiting embodiments of the above-mentioned embodiments of the present application are described in more detail below with reference to the accompanying drawings. For ease of description, in the following embodiments, STO represents the surface of the diaphragm, S1 represents the first side of the second lens E2, S2 represents the second side of the second lens E2, S3 represents the first side of the polarization beam splitter PBS, S4 represents the second side of the polarization beam splitter PBS, S5 represents the first side of the quarter-wave plate QWP, S6 represents the second side of the quarter-wave plate QWP, S7 represents the first side of the third lens E3, S8 represents the second side of the third lens E3, S9 represents the first side of the fourth lens E4, S10 represents the second side of the fourth lens E4, S11 represents the first side of the fifth lens E5, S12 represents the second side of the fifth lens E5, S13 represents the first side of the flat glass, S14 represents the second side of the flat glass, S15 represents the reflecting surface of the liquid crystal panel; K1 represents the light entrance surface of the condenser lens Ej, K2 represents the light exit surface of the condenser lens Ej, K3 represents the light entrance surface of the fly-eye lens Ef, K4 represents the light exit surface of the fly-eye lens Ef, K5 represents the light entrance surface of the first lens E1, and K6 represents the light exit surface of the first lens E1. In addition, the j-th aspheric surface coefficient is represented by Aj, and j = 4, 6, 8, 10, 12, 14, 16, 18, 20.

[0071] The specific optical path is as shown in Figure 7 In the present application, a linear polarizer LP is arranged between the polarization beam splitter PBS and the first lens E1 in the direction of the first optical axis Z1, and a quarter-wave plate QWP is arranged between the polarization beam splitter and the third lens E3 in the direction of the second optical axis Z2, wherein the quarter-wave plate QWP is bonded to the polarization beam splitter PBS. The specific optical path is as follows: the light emitted by the light source passes through the condenser lens Ej, the fly-eye lens Ef, and the first lens E1 in turn, is then screened by the linear polarizer LP at the light entrance surface of the polarization beam splitter PBS, enters the polarization beam splitter PBS in the form of linearly polarized light, the linearly polarized light is reflected by the light splitting surface, passes through the quarter-wave plate QWP, and along the second optical axis Z2 passes through the third lens E3, the fourth lens E4, and the fifth lens E5 of the imaging lens group in turn, is then reflected at the liquid crystal panel and the polarization angle is converted, is folded back along the original optical path in the direction of the second optical axis, passes through the fifth lens E5, the fourth lens E4, the third lens E3, the quarter-wave plate QWP, and the second lens E2 in turn, and is emitted from the diaphragm surface.

[0072] Example 1

[0073] like Figure 1 As shown, in this embodiment, the projection system includes a light source, a condenser Ej, a fly-eye lens Ef, a first lens E1, a polarization beam splitter prism, an imaging lens group, a liquid crystal panel and a second lens E2. The projection system also has a first optical axis Z1 and a second optical axis Z2 that are perpendicular to each other. The first optical axis Z1 and the second optical axis Z2 are respectively arranged at an angle to the beam splitting surface of the polarization beam splitter prism PBS; wherein the light source, the condenser Ej, the fly-eye lens Ef, the first lens E1 and the polarization beam splitter prism PBS are arranged in sequence along the first optical axis Z1; the liquid crystal panel, the imaging lens group, the polarization beam splitter prism PBS and the second lens E2 are arranged in sequence along the second optical axis Z2; the light source is used to emit an original light beam, the condenser Ej is used to convert the original light beam into a collimated light beam, the fly-eye lens Ef is used to convert the collimated light beam into a homogenized light beam, the liquid crystal panel is used to convert the homogenized light beam into an image light beam, and the polarization beam splitter prism PBS is used to reflect the homogenized light beam on the beam splitting surface and transmit the image light beam.

[0074] In this embodiment, the condenser Ej has positive focal power, the light incident surface K1 of the condenser Ej is concave, and the light exit surface K2 of the condenser Ej is convex. The first lens E1 has positive focal power, the light incident surface K5 of the first lens E1 is convex, and the light exit surface K6 of the first lens E1 is flat. The second lens E2 has positive focal power, the first side S1 of the second lens E2 is convex, and the second side S2 of the second lens E2 is flat. The third lens E3 has negative focal power, the first side S7 of the third lens E3 is concave, and the second side S8 of the third lens E3 is concave. The fourth lens E4 has positive focal power, the first side S9 of the fourth lens E4 is convex, and the second side S10 of the fourth lens E4 is convex. The fifth lens E5 has positive focal power, the first side S11 of the fifth lens E5 is convex, and the second side S12 of the fifth lens E5 is concave.

[0075] In addition, Tables 1 to 4 respectively show the basic optical parameters of the projection system of Example 1, wherein the units of the curvature radius and thickness / distance are all millimeters (mm).

[0076] Table 1: Basic optical parameters of the condenser Ej in the projection system of Example 1

[0077]

[0078] Table 2: Basic optical parameters of the fly-eye lens Ef in the projection system of Example 1

[0079]

[0080] Table 3: Basic optical parameters of the first lens E1 in the projection system of Example 1

[0081]

[0082] Table 4: Basic optical parameters of the partial structure of the projection system of Example 1

[0083]

[0084] In this embodiment, both the object-side surface and the image-side surface of any one of the fourth lens element E4 and the fifth lens element E5 are aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0085] ;

[0086] Where x is the distance from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient for the i-th order of the aspheric surface. Table 5 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspheric mirror surface S9 to S12 in Example 1.

[0087] Table 5: Aspheric coefficients in the projection system of Example 1

[0088]

[0089] like Figure 2 As shown, Figure 2 Based on Figure 1 The provided optical modulation function curves for the projection system at different fields of view in the meridional direction show that when the optical frequency varies from 0 to 25, the optical modulation function values ​​at multiple fields of view in the meridional direction are greater than 0.75, indicating that the projection system in this embodiment has good imaging quality.

[0090] Example 2

[0091] like Figure 3As shown, in this embodiment, the projection system comprises a light source, a condenser lens Ej, a compound eye lens Ef, a first lens E1, a polarization beam splitter PBS, an imaging lens group, a liquid crystal panel and a second lens E2, the projection system further has a first optical axis Z1 and a second optical axis Z2 perpendicular to each other, the first optical axis Z1 and the second optical axis Z2 are respectively arranged obliquely to the splitting surface of the polarization beam splitter PBS; wherein the light source, the condenser lens Ej, the compound eye lens Ef, the first lens E1 and the polarization beam splitter PBS are sequentially arranged along the first optical axis Z1; the liquid crystal panel, the imaging lens group, the polarization beam splitter PBS and the second lens E2 are sequentially arranged along the second optical axis Z2; the light source is used to emit an original light beam, the condenser lens Ej is used to convert the original light beam into a collimated light beam, the compound eye lens Ef is used to convert the collimated light beam into a uniform light beam, the liquid crystal panel is used to convert the uniform light beam into an image light beam, and the polarization beam splitter PBS is used to reflect the uniform light beam at the splitting surface and transmit the image light beam.

[0092] In this embodiment, the condenser lens Ej has positive focal power, the entrance surface K1 of the condenser lens Ej is concave, the exit surface K2 of the condenser lens Ej is convex, the first lens E1 has positive focal power, the entrance surface K5 of the first lens E1 is convex, the exit surface K6 of the first lens E1 is flat, the second lens E2 has positive focal power, the first side S1 of the second lens E2 is convex, the second side S2 of the second lens E2 is flat, the third lens E3 has negative focal power, the first side S7 of the third lens E3 is concave, the second side S8 of the third lens E3 is concave, the fourth lens E4 has negative focal power, the first side S9 of the fourth lens E4 is convex, the second side S10 of the fourth lens E4 is concave, the fifth lens E5 has positive focal power, the first side S11 of the fifth lens E5 is convex, and the second side S12 of the fifth lens E5 is convex.

[0093] In addition, Tables 6 to 9 respectively show the basic optical parameters of the projection system of Embodiment Two, wherein the units of the curvature radius and the thickness / distance are millimeters (mm).

[0094] Table 6: Basic optical parameter table of the condenser lens Ej in the projection system of Embodiment Two

[0095]

[0096] Table 7: Basic optical parameter table of the compound eye lens Ef in the projection system of Embodiment Two

[0097]

[0098] Table 8: Basic optical parameter table of the first lens E1 in the projection system of Embodiment Two

[0099]

[0100] Table 9: Basic optical parameters of the partial structure of the projection system of Example 2

[0101]

[0102] In this embodiment, both the object-side surface and the image-side surface of any one of the fourth lens element E4 and the fifth lens element E5 are aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0103] ;

[0104] Where x is the distance from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspheric surface. Table 10 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspheric mirror surface S9 to S12 in Example 1.

[0105] Table 10: Aspheric coefficients in the projection system of Example 2

[0106]

[0107] like Figure 4 As shown, Figure 4 Based on Figure 3 The provided optical modulation function curves for the projection system at different fields of view in the meridional direction show that when the optical frequency varies between 0 and 25, the optical modulation function curves for different fields of view in the meridional direction are all greater than 0.9, indicating that the projection system in this embodiment has good imaging quality.

[0108] Example 3

[0109] like Figure 5As shown, in this embodiment, the projection system includes a light source, a condenser Ej, a fly-eye lens Ef, a first lens E1, a polarization beam splitter prism PBS, an imaging lens group, a liquid crystal panel and a second lens E2. The projection system also has a first optical axis Z1 and a second optical axis Z2 that are perpendicular to each other. The first optical axis Z1 and the second optical axis Z2 are respectively arranged at an angle to the beam splitting surface of the polarization beam splitter prism PBS; wherein the light source, the condenser Ej, the fly-eye lens Ef, the first lens E1 and the polarization beam splitter prism PBS are arranged in sequence along the first optical axis Z1; the liquid crystal panel, the imaging lens group, the polarization beam splitter prism PBS and the second lens E2 are arranged in sequence along the second optical axis Z2; the light source is used to emit an original light beam, the condenser Ej is used to convert the original light beam into a collimated light beam, the fly-eye lens Ef is used to convert the collimated light beam into a homogenized light beam, the liquid crystal panel is used to convert the homogenized light beam into an image light beam, and the polarization beam splitter prism PBS is used to reflect the homogenized light beam on the beam splitting surface and transmit the image light beam.

[0110] In this embodiment, the condenser Ej has positive focal power, the light incident surface K1 of the condenser Ej is concave, and the light exit surface K2 of the condenser Ej is convex. The first lens E1 has positive focal power, the light incident surface K5 of the first lens E1 is convex, and the light exit surface K6 of the first lens E1 is flat. The second lens E2 has positive focal power, the first side S1 of the second lens E2 is convex, and the second side S2 of the second lens E2 is flat. The third lens E3 has negative focal power, the first side S7 of the third lens E3 is concave, and the second side S8 of the third lens E3 is concave. The fourth lens E4 has negative focal power, the first side S9 of the fourth lens E4 is convex, and the second side S10 of the fourth lens E4 is concave. The fifth lens E5 has positive focal power, the first side S11 of the fifth lens E5 is convex, and the second side S12 of the fifth lens E5 is concave.

[0111] In addition, Tables 11 to 14 respectively show the basic optical parameters of the projection system of Example 3, wherein the units of the curvature radius and thickness / distance are all millimeters (mm).

[0112] Table 11: Basic optical parameters of the condenser Ej in the projection system of Example 3

[0113]

[0114] Table 12: Basic optical parameters of the fly-eye lens Ef in the projection system of Example 3

[0115]

[0116] Table 13: Basic optical parameters of the first lens E1 in the projection system of Example 3

[0117]

[0118] Table 14: Basic optical parameters of the partial structure of the projection system of Example 3

[0119]

[0120] In this embodiment, both the object-side surface and the image-side surface of any one of the fourth lens element E4 and the fifth lens element E5 are aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0121] ;

[0122] Where x is the distance from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient for the i-th order of the aspheric surface. Table 15 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspheric mirror surface S9 to S12 in Example 1.

[0123] Table 15: Aspheric coefficients in the projection system of Example 3

[0124]

[0125] like Figure 6 As shown, Figure 6 Based on Figure 5 The provided optical modulation function curves for the projection system at different fields of view in the meridional direction show that when the optical frequency varies between 0 and 25, the optical modulation function curves for different fields of view in the meridional direction are all greater than 0.85, indicating that the projection system in this embodiment has good imaging quality.

[0126] In addition, the system optical parameter table of the projection system in Examples 1 to 3 is shown in Table 16.

[0127] Table 16: System optical parameters of projection system

[0128]

[0129] In summary, the projection systems in Examples 1 to 3 satisfy the relationship shown in Table 17, as shown in Table 17.

[0130] Table 17: Relationships satisfied by the projection system

[0131]

[0132] It is worth mentioning that according to an aspect of the present application, one embodiment of the present application further provides a projection light machine which can include the above-mentioned projection system and a photosensitive element arranged on the light exit side of the projection system for imaging. It can be understood that the photosensitive element mentioned in the present application can be implemented as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) but is not limited thereto, and the present application will not be described hereinafter.

[0133] In addition, according to another aspect of the present application, one embodiment of the present application further provides an electronic device which can include the above-mentioned projection light machine and a processor, the projection light machine being communicatively connected to the processor for acquiring image data and inputting the image data to the processor for processing. It can be understood that the electronic device mentioned in the present application can be implemented as a device such as a mobile phone equipped with the projection light machine but is not limited thereto, and the present application will not be described hereinafter.

[0134] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0135] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of the patent protection of the present application should be subject to the appended claims.

Claims

1. A projection system, characterized in that: The projection system comprises a light source, a condenser, a fly-eye lens, a first lens, a polarization beam splitter prism, an imaging lens group, a liquid crystal panel, and a second lens. The projection system further comprises a first optical axis and a second optical axis perpendicular to each other. The first optical axis and the second optical axis are respectively arranged obliquely with respect to the beam splitting plane of the polarization beam splitter prism. The side along the second optical axis away from the liquid crystal panel is a first side, and the side along the second optical axis close to the liquid crystal panel is a second side. The light source, the condenser, the fly-eye lens, the first lens and the polarization beam splitter prism are arranged in sequence along the first optical axis; The liquid crystal panel, the imaging lens group, the polarization beam splitter prism and the second lens are arranged in sequence along the second optical axis; The light source is used to emit an original light beam, the condenser is used to convert the original light beam into a collimated light beam, the fly-eye lens is used to convert the collimated light beam into a homogenized light beam, the liquid crystal panel is used to convert the homogenized light beam into an image light beam, and the polarization beam splitter prism is used to reflect the homogenized light beam on the beam splitting surface and transmit the image light beam; The first lens has positive refractive power, the second lens has positive refractive power, and both the first lens and the second lens are convex-planar lenses; The imaging lens group includes a third lens, a fourth lens, and a fifth lens in order from the first side to the second side along the second optical axis; the third lens has negative optical power, a first side of the third lens is concave, and a second side of the third lens is concave; the fourth lens has optical power, a first side of the fourth lens is convex; the fifth lens has positive optical power, and a first side of the fifth lens is convex; The projection system further satisfies the following conditions: 1.04≤f45 / fj≤2.45, 0.91≤|f3+f4+f5| / f2≤2.25, wherein f45 is the combined focal length of the fourth lens and the fifth lens, fj is the focal length of the condenser lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, and f2 is the focal length of the second lens.

2. The projection system according to claim 1, wherein: The first lens and the second lens are both glass spherical lenses. Among the first lens, the second lens, the third lens, the fourth lens and the fifth lens, the refractive index of the third lens is the largest.

3. The projection system according to claim 1, wherein: The condenser has positive focal power, the side of the condenser close to the polarization beam splitter prism is convex, the side of the condenser close to the light source is concave, and the fly-eye lens is a plastic lens; the center thickness of the fly-eye lens on the first optical axis is greater than the center thickness of the first lens on the first optical axis.

4. The projection system according to claim 1, wherein: The projection system also satisfies: 2.75<CTj / CT1<3.35; Wherein, CTj is the center thickness of the condenser on the first optical axis, and CT1 is the center thickness of the first lens on the first optical axis.

5. The projection system according to claim 1, wherein: The projection system also satisfies: -1.11≤R1 / R5≤-0.36; R1 is the curvature radius of the light incident surface of the first lens, and R5 is the curvature radius of the first side of the third lens.

6. The projection system according to claim 1, wherein: The projection system also satisfies: 0.9<f1 / f45<1.85; Wherein, f1 is the focal length of the first lens, and f45 is the combined focal length of the fourth lens and the fifth lens.

7. The projection system according to claim 1, wherein: The projection system also satisfies: 0.75≤(CT3+CT4) / CT5≤1.25; Wherein, CT3 is the center thickness of the third lens on the second optical axis, CT4 is the center thickness of the fourth lens on the second optical axis, and CT5 is the center thickness of the fifth lens on the second optical axis.

8. The projection system according to claim 1, wherein: The projection system also satisfies: 3.85≤(T34+T45) / CT2≤4.94; Wherein, T34 is the on-axis distance from the second side surface of the third lens to the first side surface of the fourth lens on the second optical axis, T45 is the on-axis distance from the second side surface of the fourth lens to the first side surface of the fifth lens on the second optical axis, and CT2 is the center thickness of the second lens on the second optical axis.

9. The projection system according to claim 1, wherein: The projection system further satisfies: 0.30≤|(R7+R8) / (R9+R10)|≤1.00; Among them, R7 is the curvature radius of the first side of the fourth lens, R8 is the curvature radius of the second side of the fourth lens, R9 is the curvature radius of the first side of the fifth lens, and R10 is the curvature radius of the second side of the fifth lens.

10. The projection system according to claim 1, wherein: The projection system also satisfies: -1.45≤fj / f3≤-0.72; Wherein, fj is the focal length of the condenser lens, and f3 is the focal length of the third lens.

11. The projection system according to claim 1, wherein: The projection system also satisfies: 2.20≤f5 / CT5≤8.00; Wherein, f5 is the focal length of the fifth lens, and CT5 is the center thickness of the fifth lens on the second optical axis.

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