Projection lens

Abstract

The present application discloses a projection lens, which sequentially includes, from the imaging side to the image source side along the optical axis: a first lens; a second lens with positive optical power; a third lens, the surface near the imaging side of which is convex and the surface near the image source side of which is concave; a fourth lens, the surface near the imaging side of which is convex and the surface near the image source side of which is concave or convex; a fifth lens; and a sixth lens, the surface near the imaging side of which is concave and the surface near the image source side of which is concave or convex.

Description

Technical Field

[0001] The present application relates to a projection lens, and more specifically, to a projection lens including six lenses. Background Art

[0002] In recent years, the updating and development speed of projectors has been relatively fast. Traditional projectors have been gradually phased out due to disadvantages such as large volume, high power consumption, heaviness, low brightness, and short lifespan. With the development of microdisplay elements such as LEDs and OLEDs, the projection angle of projection lenses has also broken through the traditional image-side telecentric optical path design, which is beneficial to reducing the weight and size of projectors. In addition, in order to project a larger image at a short projection distance, the projection lens needs to have a smaller projection ratio. Therefore, projection lenses with large apertures, miniaturization, and smaller projection ratios are the trend of further development.

[0003] In order to solve the above problems, the object of the present invention is to design a 6-piece micro-projection lens with low chromatic aberration, high brightness, and miniaturization. Summary of the Invention

[0004] On the one hand, the present application provides such a projection lens. The projection lens sequentially includes, from the imaging side to the image source side along the optical axis: a first lens; a second lens with positive optical power; a third lens, the surface near the imaging side of which is convex and the surface near the image source side of which is concave; a fourth lens, the surface near the imaging side of which is convex and the surface near the image source side of which is concave or convex; a fifth lens; and a sixth lens, the surface near the imaging side of which is concave and the surface near the image source side of which is concave or convex.

[0005] In one embodiment, the maximum chief ray angle of incidence MCRA on the imaging side of the projection lens satisfies: 1.5 < 1 / tan(MCRA) < 2.1.

[0006] In one embodiment, the total effective focal length f of the projection lens and the entrance pupil diameter EPD of the projection lens satisfy: f / EPD < 1.80.

[0007] In one embodiment, the relative illumination RI of the projection lens is not less than 40%.

[0008] In one embodiment, the central thickness CT1 of the first lens on the optical axis and the edge thickness ET of the first lens satisfy: 1.40 ≤ CT1 / ET1 < 1.75.

[0009] In one embodiment, the distance SAG21 on the optical axis from the intersection of the near imaging side surface of the second lens and the optical axis to the vertex of the effective radius of the near imaging side surface of the second lens and the distance SAG22 on the optical axis from the intersection of the near image source side surface of the second lens and the optical axis to the vertex of the effective radius of the near image source side surface of the second lens satisfy: 1.0 < SAG21 / SAG22 < 1.5.

[0010] In one embodiment, the total effective focal length f of the projection lens and half of the diagonal length ImgH of the effective pixel region on the image source plane of the projection lens satisfy: 1.2 < f / ImgH < 1.5.

[0011] In one embodiment, the central thickness CT3 of the third lens on the optical axis and the central thickness CT4 of the fourth lens on the optical axis satisfy: 1.0 < CT4 / CT3 < 2.1.

[0012] In one embodiment, the radius of curvature R1 of the near imaging side surface of the first lens and the radius of curvature R2 of the near image source side surface of the first lens satisfy: 0.9 < R2 / R1 < 1.5.

[0013] In one embodiment, the distance TTL on the optical axis from the near imaging side surface of the first lens to the image source plane of the projection lens and the sum ∑AT of the air gaps on the optical axis between two adjacent lenses among the first lens to the sixth lens satisfy: 2.0 < TTL / ∑AT < 3.5.

[0014] In one embodiment, the radius of curvature R5 of the near imaging side surface of the third lens, the radius of curvature R6 of the near image source side surface of the third lens, and the total effective focal length f of the projection lens satisfy: 1.7 < (R6 + R5) / f < 2.7.

[0015] In one embodiment, the total effective focal length f of the projection lens and the entrance pupil diameter EPD of the projection lens satisfy the following conditional expression: f / EPD < 1.75.

[0016] In one embodiment, the distance TTL on the optical axis from the near imaging side surface of the first lens to the image source plane of the projection lens and the sum ∑TD of the central thicknesses of the first lens to the sixth lens on the optical axis satisfy the following conditional expression: 1.0 < TTL / ∑TD < 1.2.

[0017] In one embodiment, the total effective focal length f of the projection lens and the distance TTL on the optical axis from the near imaging side surface of the first lens to the image source plane of the projection lens satisfy: 1.1 < TTL / f < 1.5.

[0018] In one embodiment, the Abbe number of the first lens and the Abbe number of the second lens satisfy: V1 - V2 > 20.

[0019] On the other hand, the present application provides a projection lens, which sequentially includes, along the optical axis from the imaging side to the image source side: a first lens having a focal power, a second lens having a positive focal power, a third lens having a positive or negative focal power, a fourth lens, a fifth lens; and a sixth lens having a negative focal power; wherein, the total effective focal length f of the projection lens, the entrance pupil diameter EPD of the projection lens, the distance TTL on the optical axis from the near imaging side surface of the first lens to the image source surface of the projection lens, and the sum ∑TD of the central thicknesses of the first lens to the sixth lens on the optical axis satisfy the following conditional expressions: f / EPD < 1.75; 1.0 < TTL / ∑TD < 1.2.

[0020] In one embodiment, the total effective focal length f of the projection lens and the distance TTL on the optical axis from the near imaging side surface of the first lens to the image source surface of the projection lens satisfy: 1.1 < TTL / f < 1.5.

[0021] In one embodiment, the Abbe number of the first lens and the Abbe number of the second lens satisfy: V1 - V2 > 20.

[0022] In one embodiment, the material of at least one lens among the first lens to the sixth lens is glass.

[0023] In one embodiment, the maximum chief ray angle of incidence MCRA on the imaging side of the projection lens satisfies: 1.5 < 1 / tan(MCRA) < 2.1.

[0024] The present application provides a projection lens that is applicable to portable electronic products, has characteristics such as miniaturization, low chromatic aberration, and good imaging quality by reasonably distributing the focal power and optimizing the optical parameters. Description of the Drawings

[0025] In conjunction with the drawings, through the following detailed description of non-limiting embodiments, other features, objectives, and advantages of the present application will become more apparent. In the drawings:

[0026] Figure 1 A schematic structural diagram of the projection lens according to Embodiment 1 of the present application is shown;

[0027] Figures 2A to 2B The relative illumination curve and distortion curve of the projection lens of Embodiment 1 are respectively shown;

[0028] Figure 3 A schematic structural diagram of the projection lens according to Embodiment 2 of the present application is shown;

[0029] Figures 4A to 4B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 2;

[0030] Figure 5 shows a schematic structural diagram of a projection lens according to Embodiment 3 of the present application;

[0031] Figures 6A to 6B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 3;

[0032] Figure 7 shows a schematic structural diagram of a projection lens according to Embodiment 4 of the present application;

[0033] Figures 8A to 8B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 4;

[0034] Figure 9 shows a schematic structural diagram of a projection lens according to Embodiment 5 of the present application;

[0035] Figures 10A to 10B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 5;

[0036] Figure 11 shows a schematic structural diagram of a projection lens according to Embodiment 6 of the present application;

[0037] Figures 12A to 12B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 6;

[0038] Figure 13 shows a schematic structural diagram of a projection lens according to Embodiment 7 of the present application;

[0039] Figures 14A to 14B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 7;

[0040] Figure 15 shows a schematic structural diagram of a projection lens according to Embodiment 8 of the present application;

[0041] Figures 16A to 16B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 8;

[0042] Figure 17 shows a schematic structural diagram of a projection lens according to Embodiment 9 of the present application;

[0043] Figures 18A to 18B respectively show the relative illumination curve and distortion curve of the projection lens of Embodiment 9. Detailed implementation manners

[0044] To better understand 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 only descriptions of exemplary embodiments of the present application and do not 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.

[0045] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the features. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0046] In the drawings, for the sake of convenience of illustration, the thickness, size and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0047] In this document, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, 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 defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens close to the image source side is called the near-image-source-side surface, and the surface of each lens close to the imaging side is called the near-imaging-side surface.

[0048] It should also be understood that the terms "comprises", "comprising", "has", "including" and / or "including having", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features rather than an individual element in the list. In addition, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0049] 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 should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning 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.

[0050] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] The features, principles and other aspects of the present application will be described in detail below.

[0052] The projection lens according to an exemplary embodiment of the present application may include, for example, six lenses, namely, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. These six lenses are arranged in sequence along the optical axis from the imaging side to the image source side. There may be a spacing distance between any two adjacent lenses among the first lens to the sixth lens.

[0053] In an exemplary embodiment, the second lens may have a positive optical power; the third lens, its surface near the imaging side is convex, and its surface near the image source side is concave; the fourth lens, its surface near the imaging side is convex, and its surface near the image source side is concave or convex; the sixth lens, its surface near the imaging side is concave, and its surface near the image source side is concave or convex.

[0054] In an exemplary embodiment, the projection lens according to the present application may satisfy: 1.5 < 1 / tan(MCRA) < 2.1, where MCRA is the maximum principal ray angle of incidence on the imaging side of the projection lens. Satisfying 1.5 < 1 / tan(MCRA) < 2.1 is beneficial to controlling the size of the maximum principal ray angle of incidence on the image plane, beneficial to balancing the projection angle of the system and the light energy utilization rate of the image source, and ensuring the high resolution and uniformity of the projection imaging picture.

[0055] In an exemplary embodiment, the projection lens according to the present application may satisfy: f / EPD < 1.80, that is, Fno < 1.80, where f is the total effective focal length of the projection lens, EPD is the entrance pupil diameter of the projection lens, and Fno is the aperture value of the projection lens. The smaller the Fno, the stronger the light-gathering ability of the system. By controlling its range, the light energy reception efficiency of the projection lens can be effectively improved, more information can be collected per unit time, and thus a projection image with higher brightness can be obtained.

[0056] In an exemplary embodiment, the projection lens according to the present application may satisfy: f / EPD < 1.75, that is, Fno < 1.75, where f is the total effective focal length of the projection lens, EPD is the entrance pupil diameter of the projection lens, and Fno is the aperture value of the projection lens. The smaller the Fno, the stronger the light-gathering ability of the system. By controlling its range, the light energy reception efficiency of the projection lens can be effectively improved, more information can be collected per unit time, and thus a projection image with higher brightness can be obtained.

[0057] In an exemplary embodiment, the relative illumination RI of the projection lens according to the present application is not less than 40%, where RI is the relative illumination of the projection lens. Meeting the requirement that RI is not less than 40% can improve the uniformity of the imaging picture on the image plane by controlling the magnitude of the relative illumination, and avoid problems such as dazzling or vignetting of the image caused by overexposure or underexposure at certain positions.

[0058] In an exemplary embodiment, the projection lens according to the present application can meet the following: 1.40 ≤ CT1 / ET1 < 1.75, where CT1 is the central thickness of the first lens on the optical axis, and ET1 is the edge thickness of the first lens. Meeting the requirement of 1.40 ≤ CT1 / ET1 < 1.75 can not only effectively control the incident angle of light on the near image source surface of the first lens by controlling the ratio of the central thickness to the edge thickness of the first lens within a certain range, ensure the matching of the field angle and the image height, but also is beneficial to reducing the tolerance sensitivity of the lens and improving the processing performance.

[0059] In an exemplary embodiment, the projection lens according to the present application can meet the following: 1.0 < SAG21 / SAG22 < 1.5, where SAG21 is the distance from the intersection of the near imaging side surface of the second lens and the optical axis to the vertex of the effective radius of the near imaging side surface of the second lens on the optical axis, and SAG22 is the distance from the intersection of the near image source side surface of the second lens and the optical axis to the vertex of the effective radius of the near image source side surface of the second lens on the optical axis. Meeting the requirement of 1.0 < SAG21 / SAG22 < 1.5 is beneficial to eliminating the spherical aberration of the system, improving the imaging quality of the projection lens, and at the same time can reasonably control the weak thickness ratio of the second lens to ensure the feasibility of its processing.

[0060] In an exemplary embodiment, the projection lens according to the present application can meet the following: 1.2 < f / ImgH < 1.5, where f is the total effective focal length of the projection lens, and ImgH is half of the diagonal length of the effective pixel area on the image source surface of the projection lens. Meeting the requirement of 1.2 < f / ImgH < 1.5 can reduce the distortion of the system and the optical total length of the system by controlling the ratio of the effective focal length to the image height of the projection lens, making the structure of the projection lens more compact.

[0061] In an exemplary embodiment, the projection lens according to the present application can meet the following: 1.0 < CT4 / CT3 < 2.1, where CT3 is the central thickness of the third lens on the optical axis, and CT4 is the central thickness of the fourth lens on the optical axis. Meeting the requirement of 1.0 < CT4 / CT3 < 2.1 can effectively correct the field curvature and astigmatism of the system, make the system have high imaging quality, and at the same time is beneficial to shortening the size of the system and realizing the miniaturization of the projection lens.

[0062] In an exemplary embodiment, the projection lens according to the present application may satisfy: 0.9 < R2 / R1 < 1.5, where R1 is the radius of curvature of the near imaging side surface of the first lens, and R2 is the radius of curvature of the near image source side surface of the first lens. Satisfying 0.9 < R2 / R1 < 1.5 can control the ratio of the radius of curvature of the near image source side surface and the near imaging side surface of the first lens within a certain range, which is beneficial to correcting the field curvature aberration of the projection lens, balancing the imaging quality of the central field of view and the peripheral field of view, and improving the overall imaging performance of the system.

[0063] In an exemplary embodiment, the projection lens according to the present application may satisfy: 2.0 < TTL / ∑AT < 3.5, where TTL is the distance on the optical axis from the near imaging side surface of the first lens to the image source surface of the projection lens, and ∑AT is the sum of the air spaces on the optical axis between adjacent two lenses from the first lens to the sixth lens. Satisfying 2.0 < TTL / ∑AT < 3.5 can adjust the distribution of light rays in each field of view, reasonably control the air spaces between the lenses, reduce the tolerance sensitivity of the system, and thus improve the production yield of the lens.

[0064] In an exemplary embodiment, the projection lens according to the present application may satisfy: 1.7 < (R6 + R5) / f < 2.7, where R5 is the radius of curvature of the near imaging side surface of the third lens, R6 is the radius of curvature of the near image source side surface of the third lens, and f is the total effective focal length of the projection lens. Satisfying 1.7 < (R6 + R5) / f < 2.7 is beneficial to reducing the stray light generated by the third lens, improving the imaging quality of the projection lens. Additionally, it is beneficial to reducing the optical size of the system.

[0065] The projection lens according to another exemplary embodiment of the present application may include six lenses, namely the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens. These six lenses are arranged in sequence along the optical axis from the imaging side to the image source side. There may be a spacing distance between any adjacent two of the first lens to the sixth lens.

[0066] In an exemplary embodiment, the first lens may have a focal power; the second lens may have a positive focal power; the third lens may have a positive or negative focal power; the sixth lens may have a negative focal power.

[0067] In an exemplary embodiment, the lens according to the present application may satisfy: f / EPD < 1.75 and 1.0 < TTL / ∑TD < 1.2, where f is the total effective focal length of the projection lens, EPD is the entrance pupil diameter of the projection lens, TTL is the distance on the optical axis from the near imaging side surface of the first lens to the image source surface of the projection lens, and ∑TD is the sum of the central thicknesses of the first lens to the sixth lens on the optical axis. Satisfying f / EPD < 1.75 and 1.0 < TTL / ∑TD < 1.2 is conducive to correcting aberrations and achieving the compactness and miniaturization of the system by reasonably controlling and matching the optical powers of the lenses; by controlling the ratio of the effective focal length of the projection lens to the entrance pupil diameter of the system, the system can have the characteristic of a large aperture, meeting the high brightness requirement for imaging of the system. In addition, by controlling the ratio of the optical total length of the system to the sum of the central thicknesses of all lenses on the optical axis, the size of the projection lens can be effectively reduced, while reducing the sensitivity of the central thickness of the projection lens and improving production efficiency.

[0068] In an exemplary embodiment, the lens according to the present application may satisfy: 1.1 < TTL / f < 1.5, where f is the total effective focal length of the projection lens, and TTL is the distance on the optical axis from the near imaging side surface of the first lens to the image source surface of the projection lens. Satisfying 1.1 < TTL / f < 1.5 is conducive to shortening the optical total length of the projection lens and achieving the thinness, lightness and miniaturization of the system.

[0069] In an exemplary embodiment, the lens according to the present application may satisfy: V1 - V2 > 20, where V1 and V2 are the Abbe numbers of the first lens and the second lens respectively. Satisfying V1 - V2 > 20 can effectively reduce the chromatic aberration of the system and improve the imaging performance of the system by matching glasses with certain different Abbe numbers.

[0070] In an exemplary embodiment, the material of at least one of the first lens to the sixth lens is glass. The refractive index and Abbe number distribution of glass materials are relatively wide, with a relatively wide range of options. At the same time, the thermal expansion coefficient of glass is low and it is less affected by the ambient temperature. Therefore, when applied to a projection lens, it can effectively reduce its temperature drift and improve the thermal stability of the system.

[0071] In an exemplary embodiment, the above projection lens may further include at least one aperture stop. The aperture stop can be set at an appropriate position as needed, for example, between the first lens and the imaging side. Optionally, the projection lens may further include other known optical projection elements, such as prisms, field lenses, etc.

[0072] The projection lens according to the above-described embodiments of the present application may employ multiple lenses, such as the six lenses described above. By reasonably distributing the optical power, surface shape, central thickness of each lens, and the axial spacing between each lens, etc., the volume of the projection lens can be effectively reduced, the sensitivity of the projection lens can be decreased, and the processability of the imaging lens can be improved, making the projection lens more conducive to production and processing. The present application proposes a solution for a six-lens lens, and this projection lens has characteristics such as low chromatic aberration, high brightness, and miniaturization.

[0073] In the embodiments of the present application, at least one of the lens surfaces of each lens is an aspherical surface, that is, at least one of the near-imaging-side surface and the near-image-source-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature continuously changes from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality. Optionally, both the imaging-side surface and the image-source-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are aspherical surfaces.

[0074] However, those skilled in the art should understand that without departing from the technical solutions claimed in the present application, the number of lenses constituting the projection lens can be changed to obtain the various results and advantages described in this specification. For example, although six lenses are described as an example in the embodiments, this projection lens is not limited to including six lenses. If necessary, this projection lens may also include other numbers of lenses.

[0075] The following further describes specific embodiments of the projection lens applicable to the above-described embodiments with reference to the drawings.

[0076] Example 1

[0077] The following refers to Figures 1 to 2B Describe the projection lens according to Embodiment 1 of the present application. Figure 1 FIG. shows a schematic structural diagram of the projection lens according to Embodiment 1 of the present application.

[0078] As Figure 1 shown, the projection lens according to an exemplary embodiment of the present application sequentially includes, along the optical axis from the imaging side to the image source side: a diaphragm STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source surface S13.

[0079] The first lens E1 has a positive focal power. Its imaging-side surface S1 is convex, and its object-source-side surface S2 is concave. The second lens E2 has a positive focal power. Its imaging-side surface S3 is convex, and its object-source-side surface S4 is concave. The third lens E3 has a negative focal power. Its imaging-side surface S5 is convex, and its object-source-side surface S6 is concave. The fourth lens E4 has a positive focal power. Its imaging-side surface S7 is convex, and its object-source-side surface S8 is convex. The fifth lens E5 has a positive focal power. Its imaging-side surface S9 is convex, and its object-source-side surface S10 is concave. The sixth lens E6 has a negative focal power. Its imaging-side surface S11 is concave, and its object-source-side surface S12 is concave. S13 can be the object-source surface. The light from the object-source surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on the screen (not shown).

[0080] By reasonably controlling and matching the convexity and concavity of the surfaces between the lenses, various aberrations of the projection lens can be effectively balanced and corrected, ensuring the imaging quality and processing yield of the system.

[0081] Table 1 shows the basic parameter table of the projection lens of Example 1, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0082]

[0083]

[0084] Table 1

[0085] In this Example 1, the focal length values of each lens from the first lens to the sixth lens are respectively: 6.17 mm, 31.38 mm, -862.49 mm, 6.89 mm, 6.14 mm, -2.19 mm. The total effective focal length f of the projection lens is 3.41 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the object-source surface S13 of the projection lens) is 4.00 mm. Half of the diagonal length of the effective pixel area on the object-source surface of the projection lens ImgH is 2.32 mm. Half of the maximum field of view angle of the projection lens Semi-FOV is 38.21°. The aperture value Fno of the projection lens is 1.70. The relative illuminance RI of the projection lens is 50%.

[0086] In Example 1, the imaging-side surface and the object-source-side surface of any one of the first lens E1 to the sixth lens E6 are aspherical surfaces. The surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0087]

[0088] Wherein, x is the sagitta of the aspherical surface at a position with a height of h along the direction parallel to the optical axis, which is the distance from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the 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 of the i-th order of the aspherical surface. Table 2 below gives the high-order term coefficients A4, A6, A8, A 10 、A 12 、A 14 、A 16 、A 18 and A 20 .

[0089] Surface number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.1994E-02 -3.9538E-02 1.0521E-01 -2.4925E-01 2.5762E-01 -1.2542E-01 2.1913E-02 0.0000E+00 0.0000E+00 S2 -6.4179E-02 -6.2848E-02 1.9630E-01 -5.3164E-01 6.7592E-01 -3.7671E-01 7.3269E-02 0.0000E+00 0.0000E+00 S3 -1.1074E-01 1.1003E-01 -9.1894E-01 3.5068E+00 -7.7879E+00 1.0590E+01 -8.3257E+00 3.4704E+00 -5.9614E-01 S4 -8.9047E-02 -7.6291E-02 4.2692E-01 -1.7055E+00 4.0922E+00 -5.5560E+00 4.2194E+00 -1.4730E+00 1.2296E-01 S5 -3.6874E-02 -8.1773E-01 3.5564E+00 -9.6762E+00 1.6002E+01 -1.5746E+01 8.2191E+00 -1.4934E+00 -1.6893E-01 S6 4.4112E-02 -1.2460E+00 4.6007E+00 -1.1007E+01 1.6922E+01 -1.6665E+01 1.0149E+01 -3.4775E+00 5.2052E-01 S7 1.5902E-01 -1.2279E+00 3.4906E+00 -6.5199E+00 7.4889E+00 -5.1300E+00 1.9968E+00 -3.8321E-01 2.2686E-02 S8 8.2902E-02 -6.9423E-01 1.4630E+00 -1.7684E+00 8.2679E-01 5.6730E-01 -9.5729E-01 5.1805E-01 -1.3145E-01 S9 1.4731E-01 -9.2677E-01 1.9936E+00 -3.0070E+00 2.7159E+00 -1.4099E+00 3.9356E-01 -4.2570E-02 -3.4895E-03 S10 1.7726E-01 -7.3341E-01 1.4786E+00 -2.1548E+00 2.0427E+00 -1.2345E+00 4.7451E-01 -1.1250E-01 1.4975E-02 S11 -5.0724E-01 1.0562E+00 -1.1270E+00 7.9098E-01 -3.7648E-01 1.2252E-01 -2.6932E-02 3.8348E-03 -3.2020E-04 S12 -7.8827E-01 1.3615E+00 -1.6213E+00 1.4077E+00 -8.8796E-01 3.9825E-01 -1.2442E-01 2.6345E-02 -3.5970E-03

[0090] Table 2

[0091] Figure 2A shows the relative illumination curve of the projection lens of Example 1, which represents the relative illumination corresponding to different image heights on the imaging plane. Figure 2B shows the astigmatism curve of the projection lens of Example 1, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 2A to 2B it can be seen that the projection lens given in Example 1 can achieve good imaging quality.

[0092] Example 2

[0093] The following will refer to Figures 3 to 4B to describe the projection lens according to Embodiment 2 of the present application. In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to those in Example 1 will be omitted. Figure 3 shows a schematic structural diagram of the projection lens according to Embodiment 2 of the present application.

[0094] As Figure 3 shown, the projection lens according to an exemplary embodiment of the present application sequentially includes, along the optical axis from the imaging side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source plane S13.

[0095] The first lens E1 has a positive focal power. Its image-forming side surface S1 is convex, and its object side surface S2 is concave. The second lens E2 has a positive focal power. Its image-forming side surface S3 is convex, and its object side surface S4 is concave. The third lens E3 has a positive focal power. Its image-forming side surface S5 is convex, and its object side surface S6 is concave. The fourth lens E4 has a positive focal power. Its image-forming side surface S7 is convex, and its object side surface S8 is concave. The fifth lens E5 has a positive focal power. Its image-forming side surface S9 is convex, and its object side surface S10 is convex. The sixth lens E6 has a negative focal power. Its image-forming side surface S11 is concave, and its object side surface S12 is convex. S13 can be the object surface. The light from the object surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0096] Table 3 shows the basic parameter table of the projection lens of Example 2, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 4 shows the higher-order term coefficients of the aspherical mirror surfaces that can be used in Example 2, where each aspherical surface type can be defined by the formula (1) given in the above Example 1.

[0097]

[0098] Table 3

[0099] In this Example 2, the focal length values of each lens from the first lens to the sixth lens are respectively: 5.47 mm, 52.02 mm, 7.93 mm, 10.16 mm, 5.35 mm, -3.90 mm. The total effective focal length f of the projection lens is 2.57 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the image-forming side surface S1 of the first lens E1 to the object surface S13 of the projection lens) is 3.62 mm. Half of the diagonal length of the effective pixel area on the object surface of the projection lens ImgH is 2.00 mm. Half of the maximum field of view angle of the projection lens Semi-FOV is 38.19°. The aperture value Fno of the projection lens is 1.28. The relative illumination RI of the projection lens is 43%.

[0100]

[0101]

[0102] Table 4

[0103] Figure 4A Shows the relative illumination curve of the projection lens of Example 2, which represents the relative illumination corresponding to different image heights on the image plane. Figure 4B Shows the astigmatism curve of the projection lens of Example 2, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 4A to 4BIt can be seen that the projection lens given in Embodiment 2 can achieve good imaging quality.

[0104] Example 3

[0105] The following refers to Figures 5 to 6B to describe the projection lens according to Embodiment 3 of the present application. Figure 5 FIG. shows a schematic structural diagram of the projection lens according to Embodiment 3 of the present application.

[0106] As Figure 5 shown, the projection lens according to an exemplary embodiment of the present application sequentially includes, along the optical axis, from the imaging side to the image source side: a diaphragm STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source surface S13.

[0107] The first lens E1 has a positive optical power, its imaging-side surface S1 is convex, and its image-source-side surface S2 is concave. The second lens E2 has a positive optical power, its imaging-side surface S3 is convex, and its image-source-side surface S4 is concave. The third lens E3 has a positive optical power, its imaging-side surface S5 is convex, and its image-source-side surface S6 is concave. The fourth lens E4 has a positive optical power, its imaging-side surface S7 is convex, and its image-source-side surface S8 is convex. The fifth lens E5 has a positive optical power, its imaging-side surface S9 is convex, and its image-source-side surface S10 is concave. The sixth lens E6 has a negative optical power, its imaging-side surface S11 is concave, and its image-source-side surface S12 is concave. S13 may be an image source surface, and the light from the image source surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0108] Table 5 shows the basic parameter table of the projection lens of Embodiment 3, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 6 shows the high-order term coefficients of the aspherical mirror surfaces that can be used in Embodiment 3, where each aspherical surface type can be defined by the formula (1) given in Embodiment 1 above.

[0109]

[0110]

[0111] Table 5

[0112] In Example 3, the focal length values of the respective lenses from the first lens to the sixth lens are: 6.03 mm, 23.78 mm, 55.05 mm, 5.49 mm, 5.65 mm, -2.39 mm. The total effective focal length f of the projection lens is 2.82 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the image source plane S13 of the projection lens) is 3.75 mm. Half of the diagonal length of the effective pixel region on the image source plane of the projection lens, ImgH, is 2.00 mm. Half of the maximum field of view angle of the projection lens, Semi-FOV, is 38.20°. The aperture value Fno of the projection lens is 1.41. The relative illuminance RI of the projection lens is 50%.

[0113] Surface number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.5844E-02 -2.4223E-02 4.1291E-02 -1.1605E-01 1.1840E-01 -6.1139E-02 1.3821E-02 0.0000E+00 0.0000E+00 S2 -6.6361E-02 -2.1377E-02 7.1912E-03 -6.2967E-02 6.3260E-02 1.3948E-02 -2.1611E-02 0.0000E+00 0.0000E+00 S3 -1.1935E-01 2.0020E-01 -1.3866E+00 5.0819E+00 -1.1127E+01 1.5033E+01 -1.1931E+01 5.0991E+00 -9.0873E-01 S4 -1.0422E-01 -2.2260E-02 2.0751E-01 -1.1573E+00 3.1958E+00 -4.6068E+00 3.6443E+00 -1.2993E+00 1.0444E-01 S5 -8.8154E-02 -4.3724E-01 2.5728E+00 -9.1852E+00 1.9637E+01 -2.6190E+01 2.1140E+01 -9.3194E+00 1.7124E+00 S6 -2.6937E-02 -1.0661E+00 5.2949E+00 -1.6098E+01 3.0658E+01 -3.7340E+01 2.8219E+01 -1.2007E+01 2.1979E+00 S7 7.8137E-02 -1.0941E+00 4.3424E+00 -1.1173E+01 1.8620E+01 -2.0233E+01 1.3809E+01 -5.3239E+00 8.7725E-01 S8 6.7780E-02 -9.0634E-01 2.9363E+00 -6.1558E+00 8.4496E+00 -7.5140E+00 4.1665E+00 -1.2989E+00 1.7244E-01 S9 1.7525E-01 -1.0430E+00 1.8947E+00 -2.0946E+00 1.2729E+00 -3.8273E-01 3.9792E-02 3.3082E-03 -5.7873E-04 S10 2.8983E-01 -1.0748E+00 1.4593E+00 -8.2983E-01 -1.1995E-01 3.9053E-01 -1.9279E-01 4.0272E-02 -3.1352E-03 S11 2.8209E-01 -2.7241E+00 6.3638E+00 -7.1989E+00 4.6148E+00 -1.7517E+00 3.8922E-01 -4.6725E-02 2.3382E-03 S12 2.1207E-01 -1.9505E+00 3.8203E+00 -3.8664E+00 2.3308E+00 -8.7126E-01 1.9839E-01 -2.5219E-02 1.3721E-03

[0114] Table 6

[0115] Figure 6A shows the relative illuminance curve of the projection lens of Example 3, which represents the relative illuminance corresponding to different image heights on the imaging plane. Figure 6B shows the astigmatism curve of the projection lens of Example 3, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 6A to 6B it can be seen that the projection lens given in Example 3 can achieve good imaging quality.

[0116] Example 4

[0117] The following refers to Figures 7 to 8B to describe the projection lens according to Embodiment 4 of the present application. Figure 7 shows a schematic structural diagram of the projection lens according to Embodiment 4 of the present application.

[0118] As Figure 7 shown, the projection lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the imaging side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source plane S13.

[0119] The first lens E1 has a positive focal power. Its imaging-side surface S1 is convex, and its object-side surface S2 is concave. The second lens E2 has a positive focal power. Its imaging-side surface S3 is convex, and its object-side surface S4 is concave. The third lens E3 has a negative focal power. Its imaging-side surface S5 is convex, and its object-side surface S6 is concave. The fourth lens E4 has a positive focal power. Its imaging-side surface S7 is convex, and its object-side surface S8 is convex. The fifth lens E5 has a positive focal power. Its imaging-side surface S9 is convex, and its object-side surface S10 is convex. The sixth lens E6 has a negative focal power. Its imaging-side surface S11 is concave, and its object-side surface S12 is concave. S13 can be the object surface. The light from the object surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0120] Table 7 shows the basic parameter table of the projection lens of Example 4, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 8 shows the high-order term coefficients of the aspherical mirror surfaces that can be used in Example 4, where each aspherical surface type can be defined by the formula (1) given in the above Example 1.

[0121]

[0122] Table 7

[0123] In this Example 4, the focal length values of the respective lenses from the first lens to the sixth lens are: 6.01 mm, 29.00 mm, -94.33 mm, 5.99 mm, 6.10 mm, -1.96 mm. The total effective focal length f of the projection lens is 3.09 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the object surface S13 of the projection lens) is 3.91 mm. Half of the diagonal length of the effective pixel region on the object surface of the projection lens is ImgH = 2.20 mm. Half of the maximum field of view angle of the projection lens is Semi-FOV = 38.98°. The aperture value Fno of the projection lens is 1.54, and the relative illumination RI of the projection lens is 59%.

[0124]

[0125]

[0126] Table 8

[0127] Figure 8A shows the relative illumination curve of the projection lens of Example 4, which represents the relative illumination corresponding to different image heights on the imaging surface. Figure 8B shows the astigmatism curve of the projection lens of Example 4, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 8A to 8BIt can be seen that the projection lens given in Embodiment 4 can achieve good imaging quality.

[0128] Example 5

[0129] The following refers to Figures 9 to 10B Describe the projection lens according to Embodiment 5 of the present application. Figure 9 The structural schematic diagram of the projection lens according to Embodiment 5 of the present application is shown.

[0130] As Figure 9 shown, the projection lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis, from the imaging side to the image source side: a diaphragm STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source surface S13.

[0131] The first lens E1 has a positive optical power, its imaging-side surface S1 is convex, and its image-source-side surface S2 is concave. The second lens E2 has a positive optical power, its imaging-side surface S3 is convex, and its image-source-side surface S4 is concave. The third lens E3 has a positive optical power, its imaging-side surface S5 is convex, and its image-source-side surface S6 is concave. The fourth lens E4 has a positive optical power, its imaging-side surface S7 is convex, and its image-source-side surface S8 is convex. The fifth lens E5 has a positive optical power, its imaging-side surface S9 is convex, and its image-source-side surface S10 is concave. The sixth lens E6 has a negative optical power, its imaging-side surface S11 is concave, and its image-source-side surface S12 is concave. S13 can be an image source surface, and the light from the image source surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0132] Table 9 shows the basic parameter table of the projection lens in Embodiment 5, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 10 shows the high-order term coefficients of the aspherical mirror surfaces that can be used in Embodiment 5, where each aspherical surface type can be defined by the formula (1) given in Embodiment 1 above.

[0133]

[0134]

[0135] Table 9

[0136] In Example 5, the focal length values of the respective lenses from the first lens to the sixth lens are: 6.67 mm, 19.05 mm, 397.97 mm, 6.11 mm, 8.00 mm, -2.29 mm. The total effective focal length f of the projection lens is 3.26 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the image source surface S13 of the projection lens) is 4.00 mm. Half of the diagonal length of the effective pixel region on the image source surface of the projection lens is ImgH = 2.44 mm. Half of the maximum field of view angle of the projection lens is Semi-FOV = 38.25°. The aperture value Fno of the projection lens is 1.63, and the relative illumination RI of the projection lens is 45%.

[0137] Surface number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.6482E-02 -2.8604E-02 5.4470E-02 -1.2654E-01 1.3090E-01 -6.7987E-02 1.5383E-02 0.0000E+00 0.0000E+00 S2 -7.7999E-02 -1.7598E-03 -8.5219E-02 2.0899E-01 -2.9238E-01 2.4119E-01 -7.8841E-02 0.0000E+00 0.0000E+00 S3 -1.0024E-01 -2.1509E-02 -1.4716E-02 1.5531E-02 3.2047E-01 -7.2750E-01 9.1321E-01 -5.9734E-01 1.5126E-01 S4 -8.5241E-02 1.8435E-02 -3.4218E-01 1.5984E+00 -4.2686E+00 7.4558E+00 -7.9041E+00 4.6603E+00 -1.1637E+00 S5 -1.1345E-01 -1.8383E-01 6.2419E-01 -1.0515E+00 -3.1150E-01 3.7488E+00 -5.7392E+00 3.8548E+00 -9.8694E-01 S6 -9.6717E-02 -3.0600E-01 9.5104E-01 -1.7896E+00 1.6150E+00 -2.7222E-01 -6.8740E-01 5.3941E-01 -1.2026E-01 S7 -2.0742E-02 -2.5259E-01 3.1726E-01 1.2593E-01 -1.2342E+00 1.8729E+00 -1.2908E+00 4.2973E-01 -5.6339E-02 S8 -5.8615E-03 -2.5624E-01 4.0227E-01 -3.9078E-01 2.0967E-01 -4.7182E-02 1.7298E-02 -5.9028E-03 -5.2205E-03 S9 5.7279E-02 -3.8784E-01 5.8002E-01 -8.6243E-01 7.2934E-01 -3.2037E-01 8.6287E-02 -2.6134E-02 8.4524E-03 S10 9.9283E-02 -3.2016E-01 5.0336E-01 -7.8631E-01 8.0746E-01 -4.9719E-01 1.8442E-01 -4.0093E-02 4.6027E-03 S11 -4.8787E-01 1.1061E+00 -1.4064E+00 1.2205E+00 -7.1882E-01 2.8569E-01 -7.5394E-02 1.2662E-02 -1.2255E-03 S12 -6.8785E-01 1.1561E+00 -1.3550E+00 1.0816E+00 -5.7505E-01 1.9862E-01 -4.2398E-02 4.8291E-03 -1.0902E-04

[0138] Table 10

[0139] Figure 10A shows the relative illumination curve of the projection lens of Example 5, which represents the relative illumination corresponding to different image heights on the imaging surface. Figure 10B shows the astigmatism curve of the projection lens of Example 5, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 10A to 10B it can be seen that the projection lens given in Example 5 can achieve good imaging quality.

[0140] Example 6

[0141] The following refers to Figures 11 to 12B to describe the projection lens according to Embodiment 6 of the present application. Figure 11 shows a schematic structural diagram of the projection lens according to Embodiment 6 of the present application.

[0142] As Figure 11 shown, the projection lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the imaging side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source surface S13.

[0143] The first lens E1 has a positive focal power. Its image-forming side surface S1 is convex, and its object side surface S2 is concave. The second lens E2 has a positive focal power. Its image-forming side surface S3 is convex, and its object side surface S4 is concave. The third lens E3 has a negative focal power. Its image-forming side surface S5 is convex, and its object side surface S6 is concave. The fourth lens E4 has a positive focal power. Its image-forming side surface S7 is convex, and its object side surface S8 is convex. The fifth lens E5 has a positive focal power. Its image-forming side surface S9 is convex, and its object side surface S10 is concave. The sixth lens E6 has a negative focal power. Its image-forming side surface S11 is concave, and its object side surface S12 is concave. S13 can be the object surface. The light from the object surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0144] Table 11 shows the basic parameter table of the projection lens of Example 6, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 12 shows the higher-order term coefficients of the aspherical mirror surfaces that can be used in Example 6, where each aspherical surface type can be defined by the formula (1) given in the above Example 1.

[0145]

[0146] Table 11

[0147] In this Example 6, the focal length values of the respective lenses from the first lens to the sixth lens are: 6.33 mm, 33.35 mm, -97.00 mm, 5.48 mm, 6.31 mm, -2.16 mm. The total effective focal length f of the projection lens is 3.15 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the image-forming side surface S1 of the first lens E1 to the object surface S13 of the projection lens) is 3.94 mm. Half of the diagonal length of the effective pixel region on the object surface of the projection lens is ImgH = 2.35 mm. Half of the maximum field of view angle of the projection lens is Semi-FOV = 41.00°. The aperture value Fno of the projection lens is 1.58, and the relative illumination RI of the projection lens is 42%.

[0148]

[0149]

[0150] Table 12

[0151] Figure 12A shows the relative illumination curve of the projection lens of Example 6, which represents the relative illumination corresponding to different image heights on the image plane. Figure 12B shows the astigmatism curve of the projection lens of Example 6, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 12A to 12BIt can be seen that the projection lens given in Embodiment 6 can achieve good imaging quality.

[0152] Example 7

[0153] The following refers to Figures 13 to 14B Describe the projection lens according to Embodiment 7 of the present application. Figure 13 The structural schematic diagram of the projection lens according to Embodiment 7 of the present application is shown.

[0154] As Figure 13 shown, the projection lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis, from the imaging side to the image source side: a diaphragm STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source surface S13.

[0155] The first lens E1 has a negative optical power, its imaging-side surface S1 is convex, and its image-source-side surface S2 is concave. The second lens E2 has a positive optical power, its imaging-side surface S3 is convex, and its image-source-side surface S4 is concave. The third lens E3 has a positive optical power, its imaging-side surface S5 is convex, and its image-source-side surface S6 is concave. The fourth lens E4 has a positive optical power, its imaging-side surface S7 is convex, and its image-source-side surface S8 is convex. The fifth lens E5 has a positive optical power, its imaging-side surface S9 is convex, and its image-source-side surface S10 is concave. The sixth lens E6 has a negative optical power, its imaging-side surface S11 is concave, and its image-source-side surface S12 is concave. S13 can be an image source surface, and the light from the image source surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on the screen (not shown).

[0156] Table 13 shows the basic parameter table of the projection lens of Embodiment 7, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 14 shows the high-order term coefficients of the aspherical mirror surfaces that can be used in Embodiment 7, and the aspherical surface types can be defined by the formula (1) given in Embodiment 1 above.

[0157]

[0158] Table 13

[0159] In Example 7, the focal length values of the respective lenses from the first lens to the sixth lens are: -100 mm, 8.07 mm, 29.51 mm, 5.16 mm, 4.80 mm, -1.92 mm. The total effective focal length f of the projection lens is 2.96 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the image-source surface S13 of the projection lens) is 4.00 mm. Half of the diagonal length of the effective pixel region on the image-source surface of the projection lens, ImgH, is 2.15 mm. Half of the maximum field of view angle of the projection lens, Semi-FOV, is 37.14°. The aperture value Fno of the projection lens is 1.48, and the relative illuminance RI of the projection lens is 45%.

[0160] Surface number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 1.7746E-02 -1.3560E-01 5.4894E-01 -1.2068E+00 1.4268E+00 -8.4886E-01 1.9970E-01 0.0000E+00 0.0000E+00 S2 -2.0384E-03 -6.9000E-01 2.6428E+00 -5.9184E+00 7.6236E+00 -5.0202E+00 1.3004E+00 0.0000E+00 0.0000E+00 S3 5.9839E-02 -1.2803E+00 5.4712E+00 -1.4842E+01 2.4912E+01 -2.5286E+01 1.5271E+01 -5.1282E+00 7.4502E-01 S4 -5.7508E-02 2.0828E-01 -2.2431E+00 8.3276E+00 -1.8571E+01 2.6216E+01 -2.2247E+01 1.0307E+01 -2.0002E+00 S5 -1.1975E-01 -4.0593E-02 -1.0943E-01 -3.1075E-01 1.6944E+00 -3.0701E+00 3.3544E+00 -2.1633E+00 6.0843E-01 S6 -1.1941E-01 -1.4108E-01 8.5968E-01 -3.5647E+00 8.2304E+00 -1.1155E+01 8.9144E+00 -3.9216E+00 7.3718E-01 S7 -8.5682E-02 -9.7859E-02 3.8816E-01 -1.1010E+00 1.8446E+00 -1.8236E+00 1.0168E+00 -2.8207E-01 3.0094E-02 S8 -8.1753E-02 -3.1908E-02 1.7371E-01 -7.6110E-01 1.8634E+00 -2.6023E+00 2.0995E+00 -9.1307E-01 1.6681E-01 S9 -2.8462E-02 1.0274E-02 -2.8023E-01 5.2532E-01 -6.1161E-01 4.2328E-01 -1.8933E-01 6.2753E-02 -1.2212E-02 S10 2.1599E-02 -4.3335E-02 -7.0667E-02 -2.3710E-02 2.5615E-01 -3.9221E-01 2.8764E-01 -1.0416E-01 1.5056E-02 S11 -2.6919E-01 1.0977E+00 -3.1766E+00 5.4136E+00 -5.6712E+00 3.6487E+00 -1.3754E+00 2.7170E-01 -2.0755E-02 S12 -5.3167E-01 1.0841E+00 -1.4085E+00 1.1206E+00 -5.7351E-01 1.9035E-01 -3.9586E-02 4.6782E-03 -2.3944E-04

[0161] Table 14

[0162] Figure 14A shows the relative illuminance curve of the projection lens of Example 7, which represents the relative illuminance corresponding to different image heights on the imaging surface. Figure 14B shows the astigmatism curve of the projection lens of Example 7, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 14A to 14B it can be known that the projection lens given in Example 6 can achieve good imaging quality.

[0163] Example 8

[0164] The following refers to Figures 15 to 16B to describe the projection lens according to Embodiment 8 of the present application. Figure 15 shows a schematic structural diagram of the projection lens according to Embodiment 8 of the present application.

[0165] As Figure 15 shown, the projection lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the imaging side to the image-source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image-source surface S13.

[0166] The first lens E1 has a positive focal power. Its imaging-side surface S1 is convex, and its object-source-side surface S2 is concave. The second lens E2 has a positive focal power. Its imaging-side surface S3 is convex, and its object-source-side surface S4 is concave. The third lens E3 has a positive focal power. Its imaging-side surface S5 is convex, and its object-source-side surface S6 is concave. The fourth lens E4 has a negative focal power. Its imaging-side surface S7 is convex, and its object-source-side surface S8 is concave. The fifth lens E5 has a positive focal power. Its imaging-side surface S9 is convex, and its object-source-side surface S10 is convex. The sixth lens E6 has a negative focal power. Its imaging-side surface S11 is concave, and its object-source-side surface S12 is concave. S13 can be the object-source surface. The light from the object-source surface of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0167] Table 15 shows the basic parameter table of the projection lens of Example 8, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 16 shows the high-order term coefficients of the aspherical mirror surfaces that can be used in Example 2, where each aspherical surface type can be defined by the formula (1) given in Example 8 above.

[0168]

[0169] Table 15

[0170] In this Example 8, the focal length values of each lens from the first lens to the sixth lens are respectively: 5.77 mm, 16.81 mm, 13.19 mm, -20.02 mm, 3.49 mm, -2.74 mm. The total effective focal length f of the projection lens is 2.90 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the object-source surface S13 of the projection lens) is 3.79 mm. Half of the diagonal length of the effective pixel region on the object-source surface of the projection lens is ImgH = 2.17 mm. Half of the maximum field of view angle of the projection lens is Semi-FOV = 36.96°. The aperture value Fno of the projection lens is 1.45, and the relative illumination RI of the projection lens is 45%.

[0171] Surface number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.3565E-02 -1.8617E-02 1.7934E-02 -5.2348E-02 2.8674E-02 -5.0091E-03 -1.1241E-04 0.0000E+00 0.0000E+00 S2 -6.6403E-02 -9.8170E-03 -1.0931E-02 -1.8712E-02 -1.5978E-02 6.5331E-02 -3.2354E-02 0.0000E+00 0.0000E+00 S3 -1.0766E-01 -7.2454E-02 7.0554E-01 -3.4290E+00 9.8264E+00 -1.6656E+01 1.6731E+01 -9.1355E+00 2.0814E+00 S4 -1.0220E-01 -2.1962E-01 1.6468E+00 -7.1817E+00 1.9552E+01 -3.2690E+01 3.2933E+01 -1.8256E+01 4.2758E+00 S5 -7.3119E-02 -1.6255E-01 1.8289E-01 -1.0730E-01 -8.1745E-01 2.5285E+00 -3.2582E+00 2.1091E+00 -5.5731E-01 S6 -1.8784E-02 -4.8587E-01 1.8478E+00 -5.6654E+00 1.0849E+01 -1.3201E+01 1.0063E+01 -4.3701E+00 8.2817E-01 S7 -2.1138E-02 -5.4851E-01 2.3241E+00 -5.8022E+00 8.6152E+00 -7.9311E+00 4.4847E+00 -1.4161E+00 1.8743E-01 S8 -1.9933E-03 -8.7361E-01 3.0557E+00 -6.0994E+00 7.5149E+00 -5.7781E+00 2.7100E+00 -7.0867E-01 7.8976E-02 S9 4.0234E-02 -6.8061E-01 1.1315E+00 -5.9124E-01 -9.7038E-01 1.7351E+00 -1.1332E+00 3.5109E-01 -4.3156E-02 S10 1.7855E-01 -7.0489E-01 9.5630E-01 -5.2068E-01 -1.5756E-01 3.3791E-01 -1.6514E-01 3.5281E-02 -2.8671E-03 S11 2.6932E-01 -2.6478E+00 6.1094E+00 -6.9751E+00 4.6690E+00 -1.9450E+00 5.0722E-01 -7.7438E-02 5.3514E-03 S12 3.3979E-01 -2.1097E+00 3.7195E+00 -3.5046E+00 2.0067E+00 -7.2224E-01 1.5991E-01 -1.9915E-02 1.0671E-03

[0172] Table 16

[0173] Figure 16A Shows the relative illumination curve of the projection lens of Example 8, which represents the relative illumination corresponding to different image heights on the imaging surface. Figure 16B Shows the astigmatism curve of the projection lens of Example 8, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 16A to 16B It can be seen that the projection lens given in Example 8 can achieve good imaging quality.

[0174] Example 9

[0175] Refer to the following Figures 17 to 18B to describe the projection lens according to Embodiment 9 of the present application. Figure 17 FIG. 1 shows a schematic structural diagram of the projection lens according to Embodiment 9 of the present application.

[0176] As Figure 17 shown, the projection lens according to an exemplary embodiment of the present application sequentially includes, along the optical axis, from the imaging side to the image source side: a diaphragm STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and an image source plane S13.

[0177] The first lens E1 has a positive optical power. Its imaging-side surface S1 is convex, and its image-source-side surface S2 is concave. The second lens E2 has a positive optical power. Its imaging-side surface S3 is convex, and its image-source-side surface S4 is concave. The third lens E3 has a negative optical power. Its imaging-side surface S5 is convex, and its image-source-side surface S6 is concave. The fourth lens E4 has a positive optical power. Its imaging-side surface S7 is convex, and its image-source-side surface S8 is convex. The fifth lens E5 has a negative optical power. Its imaging-side surface S9 is convex, and its image-source-side surface S10 is concave. The sixth lens E6 has a negative optical power. Its imaging-side surface S11 is concave, and its image-source-side surface S12 is concave. S13 may be an image source plane. The light from the image source plane of the projection lens sequentially passes through the surfaces S12 to S1 and finally forms an image on a screen (not shown).

[0178] Table 17 shows the basic parameter table of the projection lens of Embodiment 9, where the units of the radius of curvature, thickness, and focal length are all millimeters (mm). Table 18 shows the higher-order term coefficients of the aspherical mirror surfaces that can be used in Embodiment 9, where each aspherical surface type can be defined by the formula (1) given in Embodiment 1 above.

[0179]

[0180] Table 17

[0181] In Example 9, the focal length values of the respective lenses from the first lens to the sixth lens are: 5.75 mm, 22.11 mm, -75.56 mm, 5.26 mm, -379.18 mm, -2.50 mm. The total effective focal length f of the projection lens is 3.20 mm. The total length TTL of the projection lens (i.e., the distance on the optical axis from the imaging-side surface S1 of the first lens E1 to the image source plane S13 of the projection lens) is 3.99 mm. Half of the diagonal length of the effective pixel region on the image source plane of the projection lens, ImgH, is 2.20 mm. Half of the maximum field of view angle of the projection lens, Semi-FOV, is 35.94°. The aperture value Fno of the projection lens is 1.60, and the relative illumination RI of the projection lens is 44%.

[0182] Surface number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.4079E-02 1.0461E-03 -6.3535E-02 1.1244E-01 -1.4596E-01 8.8211E-02 -1.8203E-02 0.0000E+00 0.0000E+00 S2 -6.4526E-02 -1.1873E-02 -5.4526E-02 1.0755E-01 -1.6356E-01 1.4847E-01 -4.8365E-02 0.0000E+00 0.00000E+00 S3 -1.0720E-01 4.1435E-02 -2.5906E-01 5.2457E-01 -2.4887E-01 -6.2641E-01 1.4125E+00 -1.1052E+00 3.0669E-01 S4 -1.0411E-01 -2.6839E-02 2.9789E-01 -1.4210E+00 3.5445E+00 -4.6614E+00 3.3542E+00 -1.1136E+00 9.8856E-02 S5 -9.3042E-02 -4.7621E-04 -1.2046E+00 6.5811E+00 -1.9369E+01 3.3991E+01 -3.5396E+01 2.0124E+01 -4.7862E+00 S6 -7.6586E-02 -2.9495E-01 5.8050E-01 -6.9567E-01 1.8060E-01 8.6414E-01 -1.4594E+00 9.8055E-01 -2.4231E-01 S7 -9.9223E-02 8.8271E-02 -5.0256E-01 1.4649E+00 -2.9079E+00 3.9430E+00 -3.4539E+00 1.7252E+00 -3.6564E-01 S8 -9.4203E-02 9.2412E-02 -2.6187E-01 5.4422E-01 -8.4993E-01 9.8816E-01 -7.6672E-01 3.3966E-01 -6.3049E-02 S9 -4.6266E-02 -9.2574E-02 -3.5107E-01 1.1659E+00 -1.8972E+00 1.8730E+00 -1.1393E+00 3.9244E-01 -5.7995E-02 S10 8.9487E-02 -3.2079E-01 3.3908E-01 -2.5229E-01 1.1868E-01 -2.5655E-02 -1.0531E-03 1.4210E-03 -1.7400E-04 S11 -3.6495E-01 9.8083E-01 -1.5289E+00 1.4081E+00 -7.7677E-01 2.6318E-01 -5.4043E-02 6.2028E-03 -3.0648E-04 S12 -7.5563E-01 1.5362E+00 -1.9816E+00 1.5403E+00 -7.4486E-01 2.2709E-01 -4.2623E-02 4.5088E-03 -2.0602E-04

[0183] Table 18

[0184] Figure 18A shows the relative illumination curve of the projection lens of Example 9, which represents the relative illumination corresponding to different image heights on the imaging plane. Figure 18B shows the astigmatism curve of the projection lens of Example 9, which represents the meridional image plane curvature and the sagittal image plane curvature. According to Figures 18A to 18B it can be seen that the projection lens given in Example 8 can achieve good imaging quality.

[0185] In summary, Examples 1 to 9 respectively satisfy the relationships shown in Table 19.

[0186]

[0187] Table 19

[0188] The above description is only for the preferred embodiments of the present application and the description of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A projection lens, characterized in that, It sequentially includes, from the imaging side to the image source side along the optical axis: A first lens with a focal power, whose surface near the imaging side is convex and the surface near the image source side is concave; A second lens with a positive focal power, whose surface near the imaging side is convex and the surface near the image source side is concave; A third lens with a positive or negative focal power, whose surface near the imaging side is convex and the surface near the image source side is concave; A fourth lens, whose surface near the imaging side is convex and the surface near the image source side is concave or convex; A fifth lens, whose surface near the imaging side is convex and the surface near the image source side is concave or convex; A sixth lens with a negative focal power, whose surface near the imaging side is concave and the surface near the image source side is concave or convex; Among them, the number of lenses with focal power in the projection lens is six; The total effective focal length f of the projection lens, the entrance pupil diameter EPD of the projection lens, the distance TTL on the optical axis from the surface near the imaging side of the first lens to the image source surface of the projection lens, the central thickness CT3 of the third lens on the optical axis, the central thickness CT4 of the fourth lens on the optical axis, and the sum ΣTD of the distances on the optical axis from the surface near the imaging side of the first lens to the surface near the image source side of the sixth lens satisfy the following conditional expressions: 1.41 ≤ f / EPD ≤ 1.70; 1.05 ≤ TTL / ΣTD ≤ 1.12; 1.53 ≤ CT4 / CT3 < 2.

1.

2. The projection lens according to claim 1, characterized in that, The total effective focal length f of the projection lens and the distance TTL on the optical axis from the surface near the imaging side of the first lens to the image source surface of the projection lens satisfy: 1.17 ≤ TTL / f ≤ 1.

35.

3. The projection lens according to claim 1, characterized in that, The Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy: 20.3 ≤ V1 - V2 ≤ 21.

5.

4. The projection lens according to claim 1, characterized in that, The material of at least one lens among the first lens to the sixth lens is glass.

5. The projection lens according to claim 1, characterized in that, The maximum chief ray incident angle MCRA on the imaging side of the projection lens satisfies: 1.68 ≤ 1 / tan(MCRA) ≤ 2.

05.

6. The projection lens according to claim 1, characterized in that, The central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 1.44 ≤ CT1 / ET1 < 1.

75.

7. The projection lens according to claim 1, characterized in that, The distance SAG21 on the optical axis from the intersection of the surface near the imaging side of the second lens and the optical axis to the vertex of the effective radius of the surface near the imaging side of the second lens and the distance SAG22 on the optical axis from the intersection of the surface near the image source side of the second lens and the optical axis to the vertex of the effective radius of the surface near the image source side of the second lens satisfy: 1.05 ≤ SAG21 / SAG22 ≤ 1.

44.

8. The projection lens according to claim 1, characterized in that, The total effective focal length f of the projection lens and half of the diagonal length of the effective pixel region on the image source surface of the projection lens ImgH satisfy: 1.34 ≤ f / ImgH < 1.

5.

9. The projection lens according to claim 1, characterized in that, The radius of curvature R1 of the surface near the imaging side of the first lens and the radius of curvature R2 of the surface near the image source side of the first lens satisfy: 0.9 < R2 / R1 ≤ 1.

40.

10. The projection lens according to claim 1, characterized in that, The distance TTL from the near imaging side surface of the first lens to the image source surface of the projection lens on the optical axis and the sum ΣAT of the air spaces between adjacent two of the first lens to the sixth lens on the optical axis satisfy: 2.35 ≤ TTL / ΣAT ≤ 2.

66.

11. The projection lens according to claim 1, characterized in that, The radius of curvature R5 of the near imaging side surface of the third lens, the radius of curvature R6 of the near image source side surface of the third lens, and the total effective focal length f of the projection lens satisfy: 1.76 ≤ (R6 + R5) / f ≤ 2.42.

Images