Projection lens and projection display equipment

Abstract

The invention discloses a projection lens and projection display equipment, and relates to the technical field of projection display. The projection lens comprises a front group lens module, a middle group lens module and a rear group lens module which are arranged along the propagation direction of image light, the front group lens module comprises a first lens and a second lens, and the first lens is located on the side, facing the middle group lens module, of the second lens. Image light enters the second lens through the rear group lens module and the middle group lens module and forms a plurality of image light beams after being reflected by the second lens, and the plurality of image light beams enter the first lens and are transmitted from the first lens so as to be used for forming a projection picture; wherein the transmission area of the first lens is located above the optical axis of the projection lens, and the effective area, for transmitting or reflecting the image light, in the second lens is located below the optical axis of the projection lens. The aberration of the optical system can be corrected through the bidirectional optical path, and the optical performance is improved.

Description

Technical Field

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

[0002] In recent years, ultra-short throw projection technology has gradually become a hot spot in the domestic projection display market. Ultra-short throw projection display devices have small distance requirements and usually only need a projection distance of dozens of centimeters to project a large image. In related technologies, ultra-short throw projection display devices usually use a reflection method to shorten the projection distance and correct aberration through multiple lenses to achieve the effect of small distortion and high performance. However, at the front end of the projection lens of an ultra-short throw projection display device, large aberrations usually occur, such as large distortion or spherical aberration, etc., thus affecting the imaging quality. Summary of the Invention

[0003] The present invention provides a projection lens and a projection display device, aiming to solve at least one of the technical problems in related technologies to a certain extent.

[0004] In a first aspect, an embodiment of the present invention provides a projection lens, including: a front group lens module, a middle group lens module, and a rear group lens module arranged along the propagation direction of image light; the front group lens module includes: a first lens and a second lens, and the first lens is located on the side of the second lens facing the middle group lens module; the image light enters the second lens through the rear group lens module and the middle group lens module, and after being reflected by the second lens, multiple image light beams are formed, and the multiple image light beams enter the first lens and are transmitted through the first lens to form a projection image; wherein, the transmission area of the first lens is located above the optical axis of the projection lens, and the effective area of the second lens for transmitting or reflecting the image light is located below the optical axis of the projection lens.

[0005] By setting the transmission area of the first lens above the optical axis of the projection lens and setting the effective area of the second lens for transmitting or reflecting the image light below the optical axis of the projection lens, the image light passes through the rear group lens module, the middle group lens module, and the image side of the second lens and enters the second lens, and after being reflected by the object side of the second lens, image light beams are formed and enter the first lens, and the image light transmitted through the first lens is used to form a projection image. In this way, the first lens and the second lens arranged with off-axis in different directions can correct the optical system aberration through a two-way optical path to solve the problem of optical defects in a large field of view (FOV), and further improve the optical performance.

[0006] In some embodiments, multiple beams of image light exiting the second lens have a first separation point, and all of the multiple beams of image light are separated after passing through the first separation point; the projection lens satisfies: S1 > S2; where S1 is the distance between the first separation point and the second lens along the optical axis direction, and S2 is the distance between the first separation point and the first lens along the optical axis direction of the projection lens. Through the above settings, this embodiment can overcome the influence of aberrations at different positions on the performance of the projection lens and improve the imaging quality.

[0007] In some embodiments, the projection lens satisfies: (S1 + S2) / h2 > 0.8; where h2 is the height of the effective aperture of the second lens. Through the above settings, this example can achieve a smaller lens size and higher processing feasibility, can effectively reduce the lens aperture of the short projection ratio, and reduce the sensitivity of the lens tolerance, improving the lens production yield.

[0008] In some embodiments, the projection lens satisfies: 0.4 ≤ S2 / S1 < 1.0; where S1 is the distance between the first separation point and the second lens along the optical axis direction, and S2 is the distance between the first separation point and the first lens along the optical axis direction of the projection lens.

[0009] In some embodiments, the projection lens satisfies: h1 ≥ h2, where h1 is the height of the effective aperture of the first lens and h2 is the height of the effective aperture of the second lens. Through the above settings, all the image light reflected from the second lens to the first lens can be transmitted through the first lens.

[0010] In some embodiments, the first lens is an aspherical lens or a freeform lens. Through the above settings, the optical aberrations of the projection lens are corrected, and the optical performance of the projection lens is improved.

[0011] In some embodiments, the second lens is an aspherical lens or a freeform lens. Through the above settings, the optical aberrations of the projection lens are corrected, and the optical performance of the projection lens is improved.

[0012] In some embodiments, the surface of the first lens facing the middle group lens module is concave, the surface of the second lens facing away from the middle group lens module is concave, and the radius of curvature of the first lens is greater than the radius of curvature of the second lens.

[0013] In some embodiments, the first lens and the second lens each have a positive optical power. Through the above optical power settings, combined with the surface shape of the first lens with a convex object side and a concave image side, and the surface shape of the second lens with a concave object side and a convex image side, the aberrations of the projection lens can be corrected, improving the imaging quality.

[0014] In some embodiments, the middle lens group module includes: a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in a direction away from the front lens group module; wherein, the third lens has a negative optical power, the fourth lens and the fifth lens have positive optical powers, and the sixth lens has a negative optical power. By reasonably configuring the optical powers and surface shapes of the above lenses, the aberration of the projection lens is corrected, and the imaging quality is improved.

[0015] In some embodiments, the rear lens group module includes: a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens arranged in a direction away from the middle lens group module; wherein, the seventh lens and the eighth lens have positive optical powers; the ninth lens and the tenth lens have negative optical powers, and the eleventh lens, the twelfth lens, and the thirteenth lens have positive optical powers. The eighth lens is cemented to the ninth lens, and the tenth lens is cemented to the eleventh lens. By reasonably configuring the optical powers and surface shapes of the above lenses, the aberration of the projection lens is corrected, and the imaging quality is improved.

[0016] An embodiment of the present invention also provides a projection display device, including: a projection lens as described in any one of the foregoing, and an illumination device and a spatial light modulation device. The illumination beam provided by the illumination device is modulated into image light by the spatial light modulation device. The projection lens is located in the propagation path of the image light, and the image light forms a projection image through the projection lens.

[0017] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of a projection lens provided by an exemplary embodiment;

[0019] Figure 2 is an MTF curve graph of a projection lens provided by an exemplary embodiment;

[0020] Figure 3 is a longitudinal spherical aberration curve graph of a projection lens provided by an exemplary embodiment;

[0021] Figure 4 is an astigmatism curve graph of a projection lens provided by an exemplary embodiment.

[0022] Description of the Reference Numerals:

[0023] 10 - front lens group module; 11 - first lens; 12 - second lens;

[0024] 20 - Middle group lens module; 21 - Third lens; 22 - Fourth lens; 23 - Fifth lens; 24 - Sixth lens;

[0025] 30 - Rear group lens module; 31 - Seventh lens; 32 - Eighth lens; 33 - Ninth lens; 34 - Tenth lens; 35 - Eleventh lens; 36 - Twelfth lens; 37 - Thirteenth lens;

[0026] 40 - Flat glass group; 41 - First flat glass; 42 - Second flat glass; 43 - Third flat glass;

[0027] 5a - First separation point; O - Optical axis of the projection lens. Detailed implementation mode

[0028] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0029] The structure, function and implementation process of the projection lens according to the embodiments of the present invention will be described below with reference to the accompanying drawings as an example.

[0030] In addition, other components and functions of the projection lens according to the embodiments of the present invention are known to those skilled in the art. To reduce redundancy, they will not be described in detail here.

[0031] In the projection lens provided in this embodiment, the image light propagates from the image side to the object side of the projection lens. In this embodiment, for the convenience of description, the surface of each lens facing the image side is called the image side surface, and the surface facing the object side is called the object side surface.

[0032] Figure 1 It is a schematic structural diagram of a projection lens provided by an exemplary embodiment.

[0033] Please refer to Figure 1 , this embodiment provides a projection lens. The projection lens has an optical axis O and includes: a front group lens module 10, a middle group lens module 20, and a rear group lens module 30 arranged along the propagation direction of the image light.

[0034] The front group lens module 10 includes: a first lens 11 and a second lens 12. The first lens 11 is located on the side of the second lens 12 facing the middle group lens module 20. The image light enters the second lens 12 after passing through the rear group lens module 30 and the middle group lens module 20, and after being reflected by the second lens 12, a plurality of image beams are formed. The multiple image beams enter the first lens 11, and the image beams transmitted from the first lens 11 are used to form a projection screen.

[0035] Among them, along the direction perpendicular to the optical axis O of the projection lens, the transmission region of the first lens 11 and the effective region of the second lens 12 are respectively located on opposite sides of the optical axis O of the projection lens. The effective region of the second lens 12 is the region for the image light to be transmitted or reflected. Specifically, the transmission region of the first lens 11 can be located above the optical axis O of the projection lens, and the effective region of the second lens 12 for transmitting or reflecting the image light can be located below the optical axis O of the projection lens. In this embodiment, the optical axis O of the projection lens overlaps with the optical axes of the middle lens module 20 and the rear lens module 30.

[0036] Exemplarily, the second lens 12 has an effective region located below the optical axis O of the projection lens, and this effective region can participate in the propagation of the image light. The image side of the second lens 12 is a concave surface. The part of the image side of the second lens 12 located in the effective region can allow the image light to pass through. The object side of the second lens 12 is a convex surface. The part of the object side of the second lens 12 located in the effective region is a reflecting surface, which can reflect the image light incident on the second lens 12 to the first lens 11.

[0037] Optionally, the part of the image side of the second lens 12 located in the effective region can be a refracting surface, so that when the image light emitted from the middle lens module 20 passes through the refracting surface of the second lens 12 and enters the second lens 12, refraction can occur, and when the image light reflected by the reflecting surface of the second lens 12 exits from the refracting surface of the second lens 12, refraction can also occur, thus facilitating the realization of a large field of view (FOV).

[0038] In other examples, at least part of the image side of the second lens 12 can also be a reflecting surface. The image light emitted from the middle lens module 20 is reflected by the image side of the second lens 12 and enters the first lens 11.

[0039] The first lens 11 has a transmission region, and this transmission region can participate in the propagation of the image light. The object side of the first lens 11 can be a concave surface. The image side of the first lens 11 can be a convex surface. The image light reflected from the reflecting surface of the second lens 12 can be directed to the part of the object side of the first lens 11 located in the transmission region and exit from the part of the image side of the first lens 11 located in the transmission region to form a projection image.

[0040] Optionally, the object side of the first lens 11 can be a refracting surface, so that when the image light reflected from the object side of the second lens 12 enters the first lens 11 from the object side of the first lens 11, refraction can occur, which is beneficial to the realization of a large field of view. The image side of the first lens 11 can be a refracting surface, so that when the image light incident on the second lens 12 exits from the image side of the second lens 12, refraction can also occur, which is beneficial to the realization of a large field of view.

[0041] The lowest point of the transmission area of the first lens 11 is located above the upper edge ray of the image light that enters the second lens 12 from the middle lens module 20, so as to prevent the first lens 11 from interfering with the image light that is incident on the second lens 12 from the middle lens module 20. Optionally, the lower edge of the first lens 11 is located above the upper edge ray of the image light that enters the second lens 12 from the middle lens module 20.

[0042] In this embodiment, by setting the transmission area of the first lens 11 above the optical axis O of the projection lens and setting the effective area for transmitting or reflecting the image light in the second lens 12 below the optical axis O of the projection lens, the image light passes through the image side of the rear lens module 30, the middle lens module 20, and the second lens 12 and is incident on the second lens 12, and after being reflected by the object side of the second lens 12, it enters the first lens 11. The image light transmitted from the first lens 11 is used to form a projection image. In this way, the first lens 11 and the second lens 12 that are arranged with opposite off-axis directions can correct the aberration of the projection lens through a two-way optical path, so as to solve the problem of optical defects in a large field of view and improve the imaging quality.

[0043] Among them, the first lens 11 and the second lens 12 that are arranged with opposite vertical axes mean that the transmission area of the first lens 11 and the effective area of the second lens 12 are respectively located on opposite sides of the optical axis O and are both separated from the optical axis O.

[0044] In some embodiments, multiple image light beams emitted from the second lens 12 have a first separation point 5a, and all the multiple image light beams are separated after passing through the first separation point 5a; along the optical axis direction of the projection lens, the distance between the first separation point 5a and the second lens 12 is S1. Along the optical axis direction of the projection lens, the distance between the first separation point 5a and the first lens 11 is S2.

[0045] The projection lens satisfies: S1 > S2. Among them, the specific difference or ratio between S1 and S2 can be set according to actual needs. Through the above settings, this embodiment can overcome the influence of aberrations at different positions on the performance of the projection lens and improve the imaging quality.

[0046] In some examples, the projection lens satisfies: 0.4 ≤ S2 / S1 < 1.0. Exemplarily, S2 / S1 can be 0.4 or 0.45 or 0.5 or 0.55 or 0.59 or 0.6 or 0.65 or 0.7 or 0.74 or 0.8 or 0.85 or 0.9 or 0.95 or 0.99, or a ratio between any two of the above.

[0047] In some examples, taking the height of the effective aperture of the second lens 12 as h2, where h2 is also the effective aperture in the direction perpendicular to the optical axis of the projection lens, the projection lens satisfies: (S1 + S2) / h2 > 0.8. Exemplarily, (S1 + S2) / h2 can be 0.81 or 0.85 or 0.9 or 0.91 or 0.95 or 1 or greater than 1, or a value between any two of the above. Through the above settings, this example can achieve a smaller lens size and higher processing feasibility, effectively reduce the lens aperture of the short projection ratio, and reduce the lens tolerance sensitivity, improving the lens production yield.

[0048] In some examples, the projection lens satisfies: S1 / h2 ≥ 0.5. Exemplarily, S1 / h2 can be 0.5 or 0.55 or 0.57 or 0.6 or 0.65 or 0.7 or greater than 0.7, or a ratio between any two of the above.

[0049] In some embodiments, the height of the effective aperture of the first lens 11 is h1, where h1 is also the effective aperture of the first lens 11 in the direction perpendicular to the optical axis of the projection lens; the height of the effective aperture of the second lens 12 is h2, then the projection lens satisfies: h1 ≥ h2, so that the image light reflected from the second lens 12 to the first lens 11 can all be transmitted through the first lens 11.

[0050] In some examples, the projection lens satisfies: 1.5 ≥ h1 / h2 ≥ 1, which is also conducive to achieving a relatively small lens size. For example, h1 / h2 can be 1 or 1.1 or 1.126 or 1.2 or 1.3 or 1.4 or 1.5, or a ratio between any two of the above.

[0051] In some examples, the projection lens satisfies: 4 ≥ h1 / S2 ≥ 2. For example, h1 / S2 can be 2 or 2.5 or 2.7 or 3 or 3.26 or 3.5 or 3.9 or 4, or a ratio between any two of the above.

[0052] In some embodiments, the first lens 11 is an aspherical lens or a free-form lens, and / or the second lens 12 is an aspherical lens or a free-form lens, so as to correct the optical aberration of the projection lens and improve the optical performance of the projection lens.

[0053] Exemplarily, the first lens 11 is an aspherical lens and the second lens 12 is an aspherical lens; or, the first lens 11 is an aspherical lens and the second lens 12 is a free-form lens; or, the first lens 11 is a free-form lens and the second lens 12 is an aspherical lens; or, the first lens 11 is a free-form lens and the second lens 12 is a free-form lens.

[0054] In other examples, one of the first lens 11 and the second lens 12 can be an aspherical lens, and the other can be a spherical lens; or, one of the first lens 11 and the second lens 12 can be a free-form surface lens, and the other can be a spherical lens.

[0055] In some embodiments, the radius of curvature of the first lens 11 is greater than that of the second lens 12 to meet the large field of view requirement. Specifically, the radius of curvature of the image side of the first lens 11 is greater than that of the image side of the second lens 12. Among them, the specific difference or specific ratio between the radius of curvature of the first lens 11 and the radius of curvature of the second lens 12 can be set according to actual needs.

[0056] In some embodiments, at least one of the first lens 11 and the second lens 12 can be made of plastic, which can reduce the processing difficulty of the lens and is convenient for lens molding. For example, the first lens 11 is made of plastic and the second lens 12 is made of plastic; or, the first lens 11 is made of plastic and the second lens 12 is made of glass; or, the first lens 11 is made of glass and the second lens 12 is made of plastic. In other embodiments, both the first lens 11 and the second lens 12 can be made of glass.

[0057] In some embodiments, the first lens 11 and the second lens 12 respectively have positive optical powers. Through the above optical power settings, combined with the surface shape that the object side of the first lens 11 is convex and the image side is concave, and the surface shape that the object side of the second lens 12 is concave and the image side is convex, the aberration of the projection lens can be corrected and the imaging quality can be improved.

[0058] In some embodiments, the middle group lens module 20 includes: a third lens 21, a fourth lens 22, a fifth lens 23, and a sixth lens 24 arranged in a direction away from the front group lens module 10; among them, the third lens 21 has a negative optical power, the fourth lens 22 and the fifth lens 23 have positive optical powers, and the sixth lens 24 has a negative optical power. In addition, the object side of the third lens 21 is concave and the image side is concave; the object side of the fourth lens 22 is concave and the image side is convex; the object side of the fifth lens 23 is convex and the image side is concave; the object side and the image side of the sixth lens 24 are both concave.

[0059] In this embodiment, by reasonably configuring the optical powers and surface shapes of the above lenses, etc., the aberration of the projection lens can be corrected and the imaging quality can be improved.

[0060] In some embodiments, the rear lens module 30 includes: a seventh lens 31, an eighth lens 32, a ninth lens 33, a tenth lens 34, an eleventh lens 35, a twelfth lens 36, and a thirteenth lens 37 arranged in a direction away from the middle lens module 20; among them, the seventh lens 31 and the eighth lens 32 have positive optical powers; the ninth lens 33 and the tenth lens 34 have negative optical powers, and the eleventh lens 35, the twelfth lens 36, and the thirteenth lens 37 have positive optical powers. The eighth lens 32 is cemented to the ninth lens 33, and the tenth lens 34 is cemented to the eleventh lens 35.

[0061] In addition, the object side surface of the seventh lens 31 is convex, and the image side surface is concave; the object side surface of the eighth lens 32 is concave, and the image side surface is convex; the object side surface of the ninth lens 33 is concave, and the image side surface is concave; the object side surface of the tenth lens 34 is concave, and the image side surface is concave; the object side surface and the image side surface of the eleventh lens 35 are both convex; the object side surface of the twelfth lens 36 is concave, and the image side surface is convex; the object side surface of the thirteenth lens 37 is convex, and the image side surface is convex.

[0062] In this embodiment, by reasonably configuring the optical powers and surface types of the above lenses, the aberration of the projection lens is corrected, and the imaging quality is improved.

[0063] In addition, the projection lens further includes a flat glass group 40; along the direction away from the rear lens module 30, the flat glass group 40 includes a first flat glass 41, a second flat glass 42, and a third flat glass 43.

[0064] Next, taking the Figure 1 shown projection lens as an example, the structure and effect of the projection lens will be described. Along the direction from the object side towards the image side (opposite to the propagation direction of the imaging light), the projection lens sequentially includes: a second lens 12, a first lens 11, a third lens 21, a fourth lens 22, a fifth lens 23, a sixth lens 24, a seventh lens 31, an eighth lens 32, a ninth lens 33, a tenth lens 34, an eleventh lens 35, a twelfth lens 36, a thirteenth lens 37, a first flat glass 41, a second flat glass 42, and a third flat glass 43.

[0065] The first lens 11 and the second lens 12 respectively have positive optical powers. The third lens 21 has a negative optical power, the fourth lens 22 and the fifth lens 23 have positive optical powers, and the sixth lens 24 has a negative optical power. The seventh lens 31 and the eighth lens 32 have positive optical powers; the ninth lens 33 and the tenth lens 34 have negative optical powers, and the eleventh lens 35, the twelfth lens 36, and the thirteenth lens 37 have positive optical powers.

[0066] The eighth lens 32 is cemented to the ninth lens 33, and the tenth lens 34 is cemented to the eleventh lens 35. There is an air gap between the remaining adjacent lenses.

[0067] The object side surface S1 of the first lens 11 has a convex surface shape, and the image side surface S2 has a concave surface shape; the object side surface S3 of the second lens 12 has a concave surface shape, and the image side surface S4 has a convex surface shape. The object side surface S5 of the third lens 21 has a concave surface shape, and the image side surface S6 has a concave surface shape; the object side surface S7 of the fourth lens 22 has a concave surface shape, and the image side surface S8 has a convex surface shape; the object side surface S9 of the fifth lens 23 has a convex surface shape, and the image side surface S10 has a concave surface shape; the object side surface S11 and the image side surface S12 of the sixth lens 24 both have concave surface shapes. The object side surface S13 of the seventh lens 31 has a convex surface shape, and the image side surface S14 has a concave surface shape; the object side surface S15 of the eighth lens 32 has a concave surface shape, and the image side surface S16 has a convex surface shape; the object side surface S17 of the ninth lens 33 has a concave surface shape, and the image side surface S18 has a concave surface shape; the object side surface S19 of the tenth lens 34 has a concave surface shape, and the image side surface S20 has a concave surface shape; the object side surface S21 and the image side surface S22 of the eleventh lens 35 both have convex surface shapes; the object side surface S23 of the twelfth lens 36 has a concave surface shape, and the image side surface S24 has a convex surface shape; the object side surface S25 of the thirteenth lens 37 has a convex surface shape, and the image side surface S26 has a convex surface shape. The first flat glass 41 has an object side surface S27 and an image side surface S28; the second flat glass 42 has an object side surface S29 and an image side surface S30; the third flat glass 43 has an object side surface S31 and an image side surface S32. Among them, the surfaces S1 to S7, the surfaces S14 and S15, and the surfaces S23 and S24 are all aspherical surfaces; the remaining surfaces are all spherical surfaces.

[0068] Along the optical axis direction of the projection lens, the distance between the intersection of the field of view of the image light reflected by the second lens 12 and the second lens 12 is S1. Along the optical axis direction of the projection lens, the distance between the intersection of the field of view of the image light reflected by the second lens 12 and the first lens 11 is S2. The effective aperture of the first lens 11 in the direction perpendicular to the optical axis of the projection lens is h1. The effective aperture of the second lens 12 in the direction perpendicular to the optical axis of the projection lens is h2. Then the projection lens satisfies the following conditions: S2 / S1 = 0.59; (S1 + S2) / h2 = 0.91; S1 / h2 = 0.57; h1 / h2 = 1.126; h1 / S2 = 3.26.

[0069] For the projection lens of this embodiment, the projection ratio can be less than 0.3, the field of view angle can reach more than 65°, and the projection lens of this embodiment can effectively correct the aberration of the projection lens and provide a high imaging quality.

[0070] In this embodiment, the surface shape x of the aspherical lens can be defined by, but not limited to, the following aspherical formula (1):

[0071] The sagitta height; c is the paraxial curvature of the aspherical surface, c = 1 / R (that is, the paraxial curvature c is the reciprocal of the radius of curvature R); k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface.

[0073] Table 1 below shows the basic parameters of the projection lens of this embodiment. Among them, the units of the radius of curvature and the thickness are both millimeters (mm). Tables 2-1 and 2-2 below show the K values and the high-order term coefficients A4, A6, A8, A10, A12, A14, and A16 of each aspherical mirror surface S1 (i.e., surface 2 in Table 1-1) to S6 (i.e., surface 8 in Table 1-2), as well as surface S14 (i.e., surface 15 in Table 1-2), surface S15 (i.e., surface 16 in Table 1-2), surface S23 (i.e., surface 24 in Table 1-2), and surface S24 (i.e., surface 25 in Table 1-2) that can be used in the projection lens of this embodiment.

[0074]

[0075]

[0076] Table 1

[0077]

[0078] Table 2-1

[0079]

[0080] Table 2-2

[0081] Figure 2 shows the MTF curve of the imaging quality of the projection lens of this embodiment. From Figure 2 it can be seen that the ordinate values corresponding to the abscissa of 93 lp / mm (line pairs / mm) of the MTF curve are all greater than 60%, indicating that each pixel can be clearly resolved and good image quality can be obtained.

[0082] Figure 3 shows the longitudinal spherical aberration curves of the projection lens provided in this embodiment using light with wavelengths of 455 mm, 550 mm, and 630 mm, which represent the spherical aberration corresponding to different focal lengths.

[0083] Figure 4 shows the astigmatism curves of the projection lens provided in this embodiment using light with wavelengths of 455 mm, 550 mm, and 630 mm. It represents the meridional image plane curvature (curves T1, T2, and T3) and the sagittal image plane curvature (curves S1, S2, and S3), Figure 3 and Figure 4 can to a certain extent reflect that the projection lens has a low level of optical distortion.

[0084] According to Figures 2 to 4 it can be known that the projection lens of this embodiment has good imaging quality.

[0085] This embodiment also provides a projection display device, including: a projection lens, an illumination device, and a spatial light modulation device. Among them, the illumination device is used to generate illumination light, the illumination light is modulated into image light by the spatial light modulation device, and the image light is projected onto the projection lens and forms a projection image through the projection lens. Among them, the structure, function, and implementation process of the projection lens are the same as or similar to those in any of the foregoing embodiments.

[0086] It should be noted that: in the drawings, for the sake of clarity, the thickness, size, and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the spherical or aspherical shape is not limited to the spherical or aspherical shape shown in the drawings. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0087] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0088] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0089] In addition, the terms "first", "second", etc. used in the embodiments of the present invention are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated in this embodiment. Thus, the features defined with terms such as "first", "second", etc. in the embodiments of the present invention can clearly or implicitly indicate that at least one such feature is included in this embodiment. In the description of the present invention, the meaning of the word "plurality" is at least two or more, such as two, three, four, etc., unless otherwise specifically defined in the embodiments.

[0090] In the present invention, unless otherwise clearly specified or limited in the embodiments, the terms "installed", "connected", "coupled" and "fixed" etc. appearing in the embodiments shall be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or integrated. Understandably, it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements, or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific implementation circumstances.

[0091] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0092] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A projection lens, characterized in that: include: A front lens group module, a middle lens group module and a rear lens group module arranged along the propagation direction of the image light; The front lens group module comprises: a first lens and a second lens, wherein the first lens is located on a side of the second lens facing the middle lens group module; the image light is incident on the second lens via the rear lens group module and the middle lens group module, and is reflected by the second lens to form a plurality of image light beams, and the plurality of image light beams are incident on the first lens and transmitted from the first lens to form a projection screen; The transmission area of ​​the first lens is located above the optical axis of the projection lens, and the effective area of ​​the second lens for transmitting or reflecting the image light is located below the optical axis of the projection lens.

2. The projection lens according to claim 1, characterized in that: The multiple image light beams emitted by the second lens have a first separation point, and the multiple image light beams are all separated after passing through the first separation point; the projection lens satisfies: S1>S2; Among them, S1 is the distance between the first separation point and the second lens along the optical axis direction; S2 is the distance between the first separation point and the first lens along the optical axis direction of the projection lens.

3. The projection lens according to claim 2, characterized in that: The projection lens meets the following requirements: (S1+S2) / h2>0.8; Wherein, h2 is the height of the effective aperture of the second lens.

4. The projection lens according to any one of claims 2 to 3, characterized in that: The projection lens meets the following requirements: 0.4≤S2 / S1<1.0; Wherein, S1 is the distance between the first separation point and the second lens along the optical axis direction of the projection lens; S2 is the distance between the first separation point and the first lens along the optical axis direction of the projection lens.

5. The projection lens according to any one of claims 1 to 3, characterized in that: The projection lens satisfies: h1≥h2, wherein h1 is the height of the effective aperture of the first lens, and h2 is the height of the effective aperture of the second lens.

6. The projection lens according to any one of claims 1 to 3, characterized in that: The first lens is an aspherical lens or a free-form lens; And / or, the second lens is an aspherical lens or a free-form lens.

7. The projection lens according to any one of claims 1 to 3, characterized in that: The surface of the first lens facing the middle group lens module is a concave surface, the surface of the second lens away from the middle group lens module is a concave surface, and the curvature radius of the first lens is greater than the curvature radius of the second lens.

8. The projection lens according to any one of claims 1 to 3, characterized in that: The first lens and the second lens have positive refractive power.

9. The projection lens according to any one of claims 1 to 3, characterized in that: The middle group lens module comprises: a third lens, a fourth lens, a fifth lens and a sixth lens arranged in a direction away from the front group lens module; wherein the third lens has a negative optical power, the fourth lens and the fifth lens have positive optical power, and the sixth lens has a negative optical power; The rear group lens module includes: a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens arranged in a direction away from the middle group lens module; wherein the seventh lens and the eighth lens have positive focal power; the ninth lens and the tenth lens have negative focal power, the eleventh lens, the twelfth lens and the thirteenth lens have positive focal power, the eighth lens is glued to the ninth lens, and the tenth lens is glued to the eleventh lens.

10. A projection display device, characterized in that: include: The projection lens as described in any one of claims 1 to 9, and an illumination device and a spatial light modulation device, wherein the illumination light beam provided by the illumination device is modulated into image light by the spatial light modulation device, the projection lens is located in the propagation path of the image light, and the image light forms a projection picture through the projection lens.

Images