An athermalized micro-array LED projection lens

Abstract

The application discloses athermal micro-array LED projection lens, which comprises a first lens, a diaphragm, a second lens, a third lens, a fourth lens and a fifth aspherical lens arranged in sequence along a main optical axis from an object side to an image side; the first lens is a biconvex or plano-convex lens with positive focal power; the second lens is a meniscus lens with positive focal power; the third lens is a biconcave or plano-concave lens with negative focal power; the fourth lens is a meniscus or plano-convex lens with positive focal power; and the fifth aspherical lens is a meniscus aspherical lens with positive focal power. The application effectively solves the problem of serious outdoor athermalization, effectively controls the light path through the matching of important parameters such as the surface curvature, the interval and the material characteristics of the lenses, greatly shortens the lens size, reduces the lens cost, effectively controls various aberrations, improves the imaging quality and the thermal stability of the lens.

Description

Technical Field

[0001] This invention relates to the field of optical projection and optical lighting technology, and in particular to a calorimetric microarray LED projection lens. Background Technology

[0002] With the development of semiconductor technology and the diversification of the projection field, people's demand for projection devices has become more extensive and diverse. Mini projectors, with their small size and portability, have been widely used in personal entertainment, business office and education and training fields.

[0003] Most micro LED projection lenses on the market currently use traditional cooling and thermal management designs. However, as the brightness of the light source increases, the heat generated by the LED array also increases, which has a significant impact on the optical performance and lifespan of the projection system. In particular, when there are large temperature differences in outdoor environments, the lens is prone to thermal defocusing due to high and low temperatures. The high and low temperature differences lead to poor resolution and make the usage process more complicated. Furthermore, low-lumen lens optical systems are not advantageous in bright outdoor environments and cannot be simultaneously compatible with simple outdoor projection and lighting.

[0004] Therefore, in order to solve the above problems, the purpose of the embodiments of the present invention is to provide a heat-free micro-array LED projection lens, which aims to solve the problem of heat generation in micro-LED projection lenses. Summary of the Invention

[0005] The purpose of this invention is to provide a heatless micro-array LED projection lens to solve the problem of severe heatlessness in outdoor applications.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A thermalized micro-array LED projection lens includes a first lens, an aperture stop, a second lens, a third lens, a fourth lens, and a fifth aspherical lens arranged sequentially from the object side to the image side along the principal optical axis; the first lens is a biconvex or plano-convex lens with positive optical power; the second lens is a meniscus lens with positive optical power; the third lens is a biconcave or plano-concave lens with negative optical power; the fourth lens is a meniscus or plano-convex lens with positive optical power; and the fifth aspherical lens is a meniscus aspherical lens with positive optical power.

[0008] Furthermore, the focal length of the first lens of the athermalized microarray LED projection lens is... The following conditions must be met:

[0009] .

[0010] Furthermore, the focal length of the second lens of the athermalized microarray LED projection lens is... The following conditions must be met:

[0011] .

[0012] Furthermore, the focal length of the third lens of the athermalized microarray LED projection lens is... The following conditions must be met:

[0013] .

[0014] Furthermore, the focal length of the fourth lens of the athermalized microarray LED projection lens is... The following conditions must be met:

[0015] .

[0016] Furthermore, the focal length of the fifth aspherical lens of the athermalized microarray LED projection lens is... The following conditions must be met:

[0017] .

[0018] Furthermore, the focal length of the athermalized microarray LED projection lens... The total length L of the lens satisfies the following relationship:

[0019] .

[0020] Furthermore, at least one of the first lens and the second lens has a refractive index between 1.60 and 1.80;

[0021] The refractive index of the third lens is between 1.64 and 1.95.

[0022] Furthermore, at least one of the first lens and the second lens has an Abbe number between 50 and 60; the Abbe number of the third lens is between 19 and 34.

[0023] Furthermore, the aperture F of the athermalized microarray LED projection lens satisfies the following relationship:

[0024] .

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] By combining important parameters such as surface curvature, spacing, and material properties between lenses, the light path can be effectively controlled, the lens size can be significantly shortened, the lens cost can be reduced, the geometric efficiency of the lens can be effectively improved, various aberrations can be effectively controlled, the image quality can be improved, the light efficiency can be improved, and the lens has better thermal stability, effectively improving the serious phenomenon of outdoor non-heating and the problem of switching between outdoor projection systems and lighting systems. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0029] Figure 1 This is a schematic diagram of the structure of an embodiment of a pyrogen-free micro-array LED projection lens according to the present invention;

[0030] Figure 2 This is a field curvature and distortion curve diagram of an embodiment of a thermalized microarray LED projection lens of the present invention;

[0031] Figure 3 This is a schematic diagram of an embodiment of a pyrogen-free microarray LED projection lens of the present invention, showing an MTF of 20 lp / mm.

[0032] Figure 4 This is a schematic diagram showing the MTF of 12.5 mp / mm at an ambient temperature of 27°C, according to an embodiment of the athermalized micro-array LED projection lens of the present invention.

[0033] Figure 5 This is a schematic diagram showing the MTF of 12.5 mp / mm at an ambient temperature of 90°C, according to an embodiment of the athermalized micro-array LED projection lens of the present invention.

[0034] Figure 6 This is a schematic diagram showing the MTF of 12.5 mp / mm at an ambient temperature of -20°C, according to an embodiment of the athermalized micro-array LED projection lens of the present invention.

[0035] Figure 7 This is a schematic diagram of the structure of an embodiment of a pyrogen-free micro-array LED projection lens according to the present invention;

[0036] Figure 8 This is a field curvature and distortion curve diagram of an embodiment of a thermalized microarray LED projection lens of the present invention;

[0037] Figure 9 This is a schematic diagram of an embodiment of a pyrogen-free microarray LED projection lens of the present invention, showing an MTF of 20 lp / mm.

[0038] Figure 10 This is a schematic diagram showing the MTF of 12.5 mp / mm at an ambient temperature of 27°C, according to an embodiment of the athermalized micro-array LED projection lens of the present invention.

[0039] Figure 11 This is a schematic diagram showing the MTF of 12.5 mp / mm at an ambient temperature of 90°C, according to an embodiment of the athermalized micro-array LED projection lens of the present invention.

[0040] Figure 12 This is a schematic diagram showing the MTF of 12.5 mp / mm at an ambient temperature of -20°C, according to an embodiment of the athermalized micro-array LED projection lens of the present invention.

[0041] Figure 13 This is a schematic diagram simulating the light effect of an embodiment of a calorimetric microarray LED projection lens according to the present invention.

[0042] Illustration: G1, first lens; G2, second lens; G3, third lens; G4, fourth lens; G5, fifth aspherical lens. Detailed Implementation

[0043] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0045] like Figure 1 As shown, the calorimetric micro-array LED projection lens system of this application includes, from left to right: a first lens G1, an aperture ST0, a second lens G2, a third lens G3, a fourth lens G4, and a fifth aspherical lens G5; wherein, S1 is the screen end of the first lens G1, S2 is the image source end of the first lens G1, ST0 represents the aperture, S4 is the screen end of the second lens G2, S5 is the image source end of the second lens G2, S6 is the screen end of the third lens G3, S7 is the image source end of the third lens G3, S8 is the screen end of the fourth lens G4, S9 is the image source end of the fourth lens G4, S10 is the screen end of the fifth aspherical lens G5, S11 is the image source end of the fifth aspherical lens G5, and the solid line to the right of S11 is the image source end (image plane).

[0046] This invention discloses a calorimetric microarray LED projection lens, comprising five lenses. The calorimetric microarray LED projection lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, and a fifth aspherical lens G5 arranged sequentially from the object side to the image side along the principal optical axis. The first lens G1 is a biconvex or plano-convex lens with positive optical power; the second lens G2 is a meniscus lens with positive optical power; the third lens G3 is a biconcave or plano-concave lens with negative optical power; the fourth lens G4 is a meniscus or plano-convex lens with positive optical power; and the fifth aspherical lens G5 is a meniscus aspherical lens with positive optical power.

[0047] Wherein, the focal length of the first lens G1 of the athermalized micro-array LED projection lens is The following conditions must be met:

[0048] .

[0049] Lenses with a focal length between 65-79 mm serve the purpose of providing a moderate angle of view that is neither too compressed nor has obvious perspective distortion, and can converge light from the aperture.

[0050] It should be added that the units (unspecified) in the above conditions are millimeters by default, and all units not specified in this article are millimeters by default.

[0051] The focal length of the second lens G2 of the athermalized microarray LED projection lens is... The following conditions must be met:

[0052] .

[0053] Among them, the lens with a focal length between 52-62 mm has the following main features: natural viewing angle and avoidance of distortion; providing moderate depth of field; the second lens G2 is a meniscus lens, which is used to correct spherical aberration to obtain a smaller spot size and higher performance, and to reduce optical distortion and chromatic aberration.

[0054] The focal length of the third lens G3 of the athermalized microarray LED projection lens is... The following conditions must be met:

[0055] .

[0056] Here, the negative focal length is due to the fact that when the third lens G3 is a biconcave lens, it changes the propagation path of light, has a larger angle, mainly expands the light beam, and allows the lens to have a larger aperture, ensuring sufficient light efficiency.

[0057] The focal length of the fourth lens G4 of the athermalized microarray LED projection lens is... The following conditions must be met:

[0058] .

[0059] Among them, the lenses with a focal length in the range of 44mm to 90mm mainly provide a flexible field of view. When the fourth lens G4 is a positive meniscus lens, it corrects spherical aberration and has a light-gathering effect, so that the light will not be greatly lost in the system.

[0060] The focal length of the fifth aspherical lens G5 of the athermalized microarray LED projection lens is... The following conditions must be met:

[0061] .

[0062] Among them, the lenses with a focal length in the range of 40mm to 75mm, the fifth aspherical lens G5 is a meniscus lens, which is used to correct spherical aberration in order to obtain a smaller spot of confusion, reduce system optical distortion and chromatic aberration to obtain higher performance and a larger light-gathering angle, so that the light from the chip end can be well gathered in the system, and the optical system can obtain a larger aperture and higher light efficiency.

[0063] The focal length of the athermalized microarray LED projection lens The total length L of the lens satisfies the following relationship:

[0064] .

[0065] When the anechoic micro-array LED projection lens system meets the above relationships, it can optimize optical performance, improve image clarity, and reduce distortion; maintain system compactness, making micro-LED projection devices lighter and more portable; control thermal effects, reduce the impact of thermal expansion on the projected image, and ensure stability; improve the matching of projection ratio and focal length, ensuring ideal projection effect; and simplify optical design, reducing the complexity of lens assembly.

[0066] At least one of the first lens G1 and the second lens G2 has a refractive index between 1.60 and 1.80; the refractive index of the third lens G3 is between 1.64 and 1.95.

[0067] At least one of the first lens G1 and the second lens G2 has an Abbe number between 50 and 60; the Abbe number of the third lens G3 is between 19 and 34.

[0068] The aperture F of the calorific microarray LED projection lens satisfies the following relationship:

[0069] .

[0070] These design parameters, through the rational selection of refractive index, Abbe number, and aperture value, not only improve the optical performance of the athermalized microarray LED projection lens but also enhance the brightness, sharpness, and color performance of the projection system. Optimizing the refractive index and Abbe number reduces chromatic aberration and improves the quality of the projected image. The aperture design plays a crucial role in ensuring a balance between brightness and contrast, thereby achieving a high-brightness, high-definition, low-chromatic-aberration, and low-distortion projection effect. These designs make this athermalized microarray LED projection lens system more adaptable to the high demands of modern projection equipment for optical performance, compactness, and thermal management.

[0071] With the above configuration, the first lens G1, a biconvex lens, acts to converge light rays; the second lens G2, a meniscus lens, acts to correct spherical aberration, resulting in a smaller spot size and higher performance, while reducing optical distortion and chromatic aberration; the third lens G3, a biconcave lens, acts to expand the beam; the fourth lens G4, a meniscus lens, acts to correct spherical aberration; and the fifth aspherical lens G5, a meniscus aspherical lens, acts to correct spherical aberration, resulting in a smaller spot size, reducing system optical distortion and chromatic aberration, achieving higher performance, and having a larger light-gathering angle, thus enabling this optical system to achieve higher light efficiency.

[0072] This athermalized micro-array LED projection lens, through the precise design of five lenses and a reasonable focal length configuration and lens combination, successfully achieves the following functions:

[0073] By optimizing the focal length and lens type, aberrations, chromatic aberration, and distortion are reduced, thus improving image quality.

[0074] The rational design reduces the negative impact of thermal effects on imaging, improving the stability and durability of the equipment;

[0075] It meets the stringent requirements of miniature LED projection systems in terms of size and weight, enabling the creation of small and lightweight projection devices;

[0076] Suitable for high-performance, high-definition projection needs, while ensuring the high efficiency and stability of the device;

[0077] Through innovative optical design, this system optimizes the imaging effect and stability of the projection system, adapting to the requirements of modern portable projection devices in terms of size, performance, and thermal management.

[0078] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0079] Example 1:

[0080] like Figure 1As shown, this invention discloses a calorimetric microarray LED projection lens, comprising five lenses. The calorimetric microarray LED projection lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, and a fifth aspherical lens G5 arranged sequentially from the object side to the image side along the principal optical axis. The first lens G1 is a positive power biconvex lens with a convex surface S1 near the object side and a convex surface S2 near the image side. The second lens G2 is a positive power concave-convex lens with a convex surface S4 near the object side and a concave surface S5 near the image side. The third lens G3 is a negative power biconcave lens with a concave surface S6 near the object side and a concave surface S7 near the image side. The fourth lens G4 is a positive power concave-convex lens with a concave surface S8 near the object side and a convex surface S9 near the image side. The fifth aspherical lens G5 is a positive power meniscus aspherical lens with a convex surface S10 near the object side and a concave surface S11 near the image side.

[0081] It should be noted that the second lens G2 is a meniscus lens, which is also a concave-convex lens. The two are different names for the same thing, but for the sake of convenience, the terms concave-convex are used to distinguish them.

[0082] Detailed optical data for the pyrolysis-free microarray LED projection lens in this embodiment are shown in Tables 1-1 and 1-2 below.

[0083] Table 1-1:

[0084]

[0085] Where R is the radius of curvature, D is the lens thickness or air gap, nd represents the refractive index, and vd represents the Abbe number.

[0086] Table 1-2:

[0087]

[0088] The formula for aspherical surfaces is as follows:

[0089] ;

[0090] In the formula, Z is the height r of the aspherical surface at its vertex along the optical axis, k is the conic coefficient, and c is the curvature of the surface vertex. ...etc. are coefficients of higher-order aspherical surfaces.

[0091] According to Tables 1-1 and 1-2 above, its maximum field of view is 18.4° and its focal length is 39.9mm.

[0092] Figures 1 to 6The figures, in sequence, show the structural schematic diagram, field curvature and distortion curves, MTF 20 lp / mm, MTF 12.5 mp / mm at ambient temperature (27℃), MTF 12.5 mp / mm at ambient temperature (90℃), and MTF 12.5 mp / mm at ambient temperature (-20℃). As can be seen from the figures, the maximum field of view with distortion correction in this system is less than 1.2%, the entire optical system has high resolution, its maximum MTF can reach 20 lp / mm ≥ 0.3, its performance at ambient temperature (27℃) can reach approximately 12.5 lp / mm ≥ 0.57, its performance at high temperature (90℃) can reach approximately 12.5 lp / mm ≥ 0.5, and its performance at low temperature (-20℃) can reach approximately 12.5 lp / mm ≥ 0.47.

[0093] In summary, the MTF performance at the above temperatures demonstrates that the lens exhibits stable performance at high and low temperatures under varying environmental conditions, and its pyrolysis performance is excellent.

[0094] Reference Figure 13 According to the lens simulation lighting effect, the maximum lighting effect of this embodiment reaches 39% and the minimum reaches 36.5%.

[0095] Example 2:

[0096] like Figure 1 As shown, this invention discloses a calorimetric microarray LED projection lens, comprising five lenses. The calorimetric microarray LED projection lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, and a fifth aspherical lens G5 arranged sequentially from the object side to the image side along the principal optical axis. The first lens G1 is a plano-convex lens with positive optical power, having a convex surface S1 near the object side and a plane S2 near the image side. The second lens G2 is a concave-convex lens with positive optical power, having a convex surface S4 near the object side and a concave surface S5 near the image side. The third lens G3 is a plano-concave lens with negative optical power, having a plane S6 near the object side and a concave surface S7 near the image side. The fourth lens G4 is a concave-convex lens with positive optical power, having a concave surface S8 near the object side and a convex surface S9 near the image side. The fifth aspherical lens G5 is a meniscus aspherical lens with positive optical power, having a convex surface S10 near the object side and a concave surface S11 near the image side.

[0097] It should be noted that in this second embodiment, since the first lens G1 is close to the image side by plane S2, in actual use, the aperture ST0 and plane S2 are in contact, resulting in the aperture ST0 and plane S2 coinciding.

[0098] Detailed optical data for the pyrolysis microarray LED projection lens in this embodiment two are shown in Tables 2-1 and 2-2 below.

[0099] Table 2-1:

[0100]

[0101] In Table 2-1, R represents the radius of curvature, D represents the lens thickness or air gap, nd represents the refractive index, and vd represents the Abbe number.

[0102] Table 2-2:

[0103]

[0104] The formula for aspherical surfaces is as follows:

[0105] ;

[0106] In the formula, Z is the height r of the aspherical surface at its vertex along the optical axis, k is the conic coefficient, and c is the curvature of the surface vertex. ...etc. are coefficients of higher-order aspherical surfaces.

[0107] As can be seen from Tables 2-1 and 2-2 above, its maximum field of view is 20° and its focal length is 39.9.

[0108] Figures 7 to 12 The figures, in sequence, show the structural schematic, field curvature and distortion curves, MTF 20 lp / mm, MTF 12.5 mp / mm at ambient temperature (27°C), MTF 12.5 mp / mm at ambient temperature (90°C), and MTF 12.5 mp / mm at ambient temperature (-20°C). As can be seen from the figures, the maximum field of view for distortion correction in this system is less than 1.2%; the entire optical system has high resolution, with a maximum MTF of 20 lp / mm ≥ 0.3; its performance at ambient temperature (27°C) is approximately 12.5 lp / mm ≥ 0.53; its performance at high temperature (90°C) is approximately 12.5 lp / mm ≥ 0.5; and its performance at low temperature (-20°C) is approximately 12.5 lp / mm ≥ 0.05.

[0109] In summary, the MTF performance at the above temperatures demonstrates that the lens exhibits stable performance at high and low temperatures under varying environmental conditions, and its pyrolysis performance is excellent.

[0110] Reference Figure 13 According to the lens simulation lighting effect, the maximum lighting effect of this embodiment reaches 39% and the minimum reaches 36.5%.

[0111] Through the above embodiments, the lens layout of the optical system of the optical lens, arranged in the order from object to image along the principal optical axis, is as follows: first lens G1, aperture ST0, second lens G2, third lens G3, fourth lens G4, and fifth aspherical lens G5, at least aspherical lenses. By matching important parameters such as surface curvature, spacing, and material properties between the lenses, the light path can be effectively controlled, significantly shortening the lens size, reducing lens cost, and effectively improving the lens's geometric efficiency. It can also effectively control various aberrations, improve image quality, enhance light efficiency, and provide better thermal stability. In the optical system embodiments of the present invention, the lens size can be shortened and costs reduced while improving projection quality, achieving thermal imaging performance under high internal and external high-temperature environments, and possessing a larger aperture to ensure excellent light efficiency.

[0112] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calorimetric micro-array LED projection lens, characterized in that, The pyrogen-free micro-array LED projection lens is composed of a first lens, an aperture, a second lens, a third lens, a fourth lens, and a fifth aspherical lens arranged sequentially along the main optical axis from the object side to the image side. The first lens is a biconvex lens with positive optical power or a plano-convex lens with a flat image side; The second lens is a meniscus lens with positive optical power and a convex object side; The third lens is a biconcave lens with negative optical power or a plano-concave lens with a flat object side; The fourth lens is a meniscus lens with a concave object side or a plano-convex lens with a flat object side and positive optical power. The fifth aspherical lens is a meniscus aspherical lens with positive optical power and a convex object side; The focal length of the first lens of the athermalized microarray LED projection lens is The following conditions must be met: ； The focal length of the second lens of the athermalized microarray LED projection lens is The following conditions must be met: ； The focal length of the third lens of the athermalized microarray LED projection lens is The following conditions must be met: ； The focal length of the fourth lens of the athermalized microarray LED projection lens is The following conditions must be met: ； The focal length of the fifth aspherical lens of the athermalized microarray LED projection lens is The following conditions must be met: ； The focal length of the athermalized microarray LED projection lens The total length L of the lens satisfies the following relationship: 。 2. The calorific micro-array LED projection lens according to claim 1, characterized in that, At least one of the first lens and the second lens has a refractive index between 1.60 and 1.80; The refractive index of the third lens is between 1.64 and 1.

95.

3. The pyrolysis-free microarray LED projection lens according to claim 1, characterized in that, At least one of the first lens and the second lens has an Abbe number between 50 and 60; The Abbe number of the third lens is between 19 and 34.

4. The pyrolysis-free microarray LED projection lens according to claim 1, characterized in that, The aperture F of the calorific microarray LED projection lens satisfies the following relationship: 。

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