A micro-projection lens and a projection system

Abstract

The application discloses a micro projection lens and a projection system, which comprise a first lens group, a second lens group and a third lens group from an object side to an image side in sequence; the first lens group comprises at least one aspherical lens, the second lens group comprises at least one aspherical lens, and the third lens group comprises at least one aspherical lens and a group of cemented lenses; the first lens group is used for reducing distortion aberration; the second lens group is used for reducing spherical aberration and reducing the projection size; and the third lens group is used for reducing chromatic aberration. The embodiment of the application can reduce the size and weight of the projection lens, improve the projection quality, and can be widely applied to the field of optical technology.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a miniature projection lens and projection system. Background Technology

[0002] With the development of semiconductor technology, portable electronic products are becoming increasingly diversified, leading to a growing demand for mini projectors. For mini projectors to achieve widespread application, the size and weight of the projection system need to be further reduced, while maintaining high projection quality and becoming more portable. Summary of the Invention

[0003] In view of this, in order to solve one of the above problems, the purpose of this invention is to provide a miniature projection lens and projection system that can reduce the size and weight of the projection lens and improve the projection quality.

[0004] On one hand, embodiments of the present invention provide a miniature projection lens, which includes a first lens group, a second lens group, and a third lens group in sequence from the object side to the image side; the first lens group includes at least one aspherical lens, the second lens group includes at least one aspherical lens, and the third lens group includes at least one aspherical lens and a set of cemented lenses;

[0005] The first lens group is used to reduce distortion aberrations;

[0006] The second lens group is used to reduce spherical aberration and decrease the projected size;

[0007] The third lens group is used to reduce chromatic aberration.

[0008] Optionally, the first lens group includes a first lens and a second lens, both of which are meniscus lenses; the second lens group includes a third to a sixth lens, the third lens being a biconcave lens, the fourth lens being a meniscus lens, and the fifth and sixth lenses both being biconvex lenses, the fourth and fifth lenses forming a first cemented lens; the third lens group includes a seventh, an eighth, and a ninth lens, the seventh and ninth lenses both being biconvex lenses, the eighth lens being a meniscus lens, and the seventh and eighth lenses forming a second cemented lens.

[0009] Optionally, the first lens group includes an eleventh lens and a twelfth lens, both of which are meniscus lenses; the second lens group includes thirteenth to sixteenth lenses, the thirteenth lens being a biconcave lens, the fourteenth and sixteenth lenses both being biconvex lenses, and the fifteenth lens being a meniscus lens, the thirteenth, fourteenth, and fifteenth lenses forming a third cemented lens; the third lens group includes seventeenth to twenty-second lenses, the seventeenth and twentieth lenses both being biconcave lenses, the eighteenth, nineteenth, twenty-first, and twenty-second lenses being biconvex lenses, the seventeenth and eighteenth lenses forming a fourth cemented lens, and the twentieth and twenty-first lenses forming a fifth cemented lens.

[0010] Optionally, the focal length of the micro-projection lens and the length of the projection lens satisfy the following relationship:

[0011] 0.05 <f / L<0.07

[0012] Where f represents the focal length of the micro-projection lens, and L represents the length of the micro-projection lens.

[0013] Optionally, the focal length of the micro-projection lens and the focal length of the first lens group satisfy the following relationship:

[0014] -0.6 <f / f1<-0.3

[0015] Where f represents the focal length of the micro-projection lens, and f1 represents the focal length of the first lens group.

[0016] Optionally, the focal length of the first lens group and the focal length of the second lens group satisfy the following relationship:

[0017] -0.7 <f1 / f2<-0.3

[0018] Where f1 represents the focal length of the first lens group and f2 represents the focal length of the second lens group.

[0019] Optionally, the focal length of the first lens group and the focal length of the third lens group satisfy the following relationship:

[0020] -0.9 <f1 / f3<-0.6

[0021] Where f1 represents the focal length of the first lens group and f3 represents the focal length of the third lens group.

[0022] Optionally, the first lens group may contain at least one aspherical lens with an Abbe number between 40 and 60.

[0023] Optionally, the third lens group may contain at least one aspherical lens with an Abbe number between 55 and 90.

[0024] On the other hand, embodiments of the present invention provide a projection system including a prism and the aforementioned micro-projection lens.

[0025] Implementing the embodiments of the present invention has the following beneficial effects: In this embodiment, the micro-projection lens includes a first lens group, a second lens group, and a third lens group from the object side to the image side. The first lens group includes at least one aspherical lens, the second lens group includes at least one aspherical lens, and the third lens group includes at least one aspherical lens and a set of cemented lenses. The first lens group reduces distortion aberrations, the second lens group reduces spherical aberration and shrinks the projection size, and the third lens group reduces chromatic aberration. Through the cooperation between the lens groups, it has the characteristics of fewer lenses and simple structure, and can significantly reduce the size and weight of the lens and reduce the lens cost. While improving geometric efficiency, it has high projection quality, low image distortion, and can support 4K resolution. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a miniature projection lens provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a miniature projection lens according to a specific embodiment of the present invention;

[0028] Figure 3 Field curvature and distortion curves of a micro-projection lens according to a specific embodiment of the present invention;

[0029] Figure 4 A schematic diagram of the MTF of a micro-projection lens according to a specific embodiment of the present invention;

[0030] Figure 5 A schematic diagram of the structure of a miniature projection lens according to another specific embodiment of the present invention;

[0031] Figure 6 Field curvature and distortion curves of a micro-projection lens provided as another specific embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the MTF of a micro-projection lens according to another specific embodiment of the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0034] See Figure 1 This invention provides a miniature projection lens, which includes a first lens group (G1), a second lens group (G2), and a third lens group (G3) in sequence from the object side to the image side; the first lens group (G1) includes at least one aspherical lens, the second lens group (G2) includes at least one aspherical lens, and the third lens group (G3) includes at least one aspherical lens and a set of cemented lenses.

[0035] The first lens group (G1) is used to reduce distortion aberrations;

[0036] The second lens group (G2) is used to reduce spherical aberration and shrink the projected size;

[0037] The third lens group (G3) is used to reduce chromatic aberration.

[0038] It should be noted that the lenses included in the first lens group, the second lens group, and the third lens group are determined according to the actual application, and this embodiment does not impose specific limitations.

[0039] The miniature projection lens also includes an aperture stop, which is positioned between the second lens group and the third lens group.

[0040] Optionally, the first lens group includes a first lens and a second lens, both of which include meniscus lenses; the second lens group includes a third to a sixth lens, the third lens including a biconcave lens, the fourth lens including a meniscus lens, and the fifth and sixth lenses both including biconvex lenses, the fourth and fifth lenses forming a first cemented lens; the third lens group includes a seventh, an eighth, and a ninth lens, the seventh and ninth lenses both including biconvex lenses, the eighth lens including a meniscus lens, and the seventh and eighth lenses forming a second cemented lens.

[0041] It should be noted that the first and second lenses are both negative power aspherical lenses, the third lens is a negative power aspherical lens, the fourth and fifth lenses are positive power lenses, the sixth lens is a positive power aspherical lens, the seventh lens is a positive power lens, the eighth lens is a negative power lens, and the ninth lens is a positive power aspherical lens.

[0042] Optionally, the first lens group includes an eleventh lens and a twelfth lens, both of which include meniscus lenses; the second lens group includes thirteenth to sixteenth lenses, the thirteenth lens including a biconcave lens, the fourteenth and sixteenth lenses both including biconvex lenses, and the fifteenth lens including a meniscus lens, the thirteenth, fourteenth, and fifteenth lenses forming a third cemented lens; the third lens group includes seventeenth to twenty-second lenses, the seventeenth and twentieth lenses both including biconcave lenses, the eighteenth, nineteenth, twenty-first, and twenty-second lenses including biconvex lenses, the seventeenth and eighteenth lenses forming a fourth cemented lens, and the twentieth and twenty-first lenses forming a fifth cemented lens.

[0043] It should be noted that the eleventh lens is a negative power aspherical lens, the twelfth lens is a negative power lens, the thirteenth and fifteenth lenses are both negative power lenses, the fourteenth lens is a positive power lens, the sixteenth lens is a positive power aspherical lens, the seventeenth and twentieth lenses are negative power lenses, the eighteenth and twenty-first lenses are positive power lenses, and the nineteenth and twenty-second lenses are positive power aspherical lenses.

[0044] Optionally, the focal length of the micro-projection lens and the length of the conventional projection lens satisfy the following relationship:

[0045] 0.05 <f / L<0.07

[0046] Where f represents the focal length of the micro-projection lens, and L represents the length of the micro-projection lens.

[0047] It should be noted that the focal length of the micro-projection lens and the length of the micro-projection lens are determined according to the actual application, and this embodiment does not impose specific limitations.

[0048] Optionally, the focal length of the miniature projection lens and the focal length of the first lens group satisfy the following relationship:

[0049] -0.6 <f / f1<-0.3

[0050] Where f represents the focal length of the micro-projection lens, and f1 represents the focal length of the first lens group.

[0051] It should be noted that the focal length of the micro-projection lens and the focal length of the first lens group are determined according to the actual application, and this embodiment does not impose specific limitations.

[0052] Optionally, the focal lengths of the first lens group and the second lens group satisfy the following relationship:

[0053] -0.7 <f1 / f2<-0.3

[0054] Where f1 represents the focal length of the first lens group and f2 represents the focal length of the second lens group.

[0055] It should be noted that the focal lengths of the first lens group and the second lens group are determined according to the actual application, and this embodiment does not impose specific limitations.

[0056] Optionally, the focal lengths of the first lens group and the third lens group satisfy the following relationship:

[0057] -0.9 <f1 / f3<-0.6

[0058] Where f1 represents the focal length of the first lens group and f3 represents the focal length of the third lens group.

[0059] It should be noted that the focal lengths of the first lens group and the third lens group are determined according to the actual application, and this embodiment does not impose specific limitations.

[0060] Optionally, the Abbe number of at least one aspherical lens in the first lens group is between 40 and 60.

[0061] It should be noted that the Abbe number of at least one aspherical lens in the first lens group is determined based on the actual application, and this embodiment does not impose specific restrictions.

[0062] Optionally, the Abbe number of at least one aspherical lens in the third lens group is between 55 and 90.

[0063] It should be noted that the Abbe number of at least one aspherical lens in the third lens group is determined based on the actual application, and this embodiment does not impose specific limitations.

[0064] On the other hand, embodiments of the present invention provide a projection system including a prism and the aforementioned micro-projection lens.

[0065] The projection system includes, but is not limited to, prisms and the aforementioned micro-projection lenses, and may also include housings or support devices.

[0066] The projection system will be described below using two specific embodiments.

[0067] Implementation 1

[0068] See Figure 2The projection system consists of a first lens group (G1), a second lens group (G2), and a third lens group (G3) from the object side to the image side. The first lens group (G1) includes a first lens (L1) and a second lens (L2). The first lens (L1) is a meniscus negative power aspherical lens with an Abbe number between 40 and 60. The second lens (L2) is also a meniscus negative power aspherical lens. The second lens group (G2) includes lenses three through six (L6). The third lens (L3) is a biconcave negative power lens. A fourth lens (L4) with meniscus positive power and a fifth lens (L5) with biconvex positive power form a cemented lens. The sixth lens (L6) is a biconvex positive power aspherical lens. The third lens group (G3) includes the seventh lens (L7) to the ninth lens (L9). The seventh lens (L7), which is biconvex and has positive optical power, and the eighth lens (L8), which is meniscus and has negative optical power, form a cemented lens. The ninth lens (L9) is a biconvex and positive optical power aspherical lens with an Abbe number between 55 and 90.

[0069] The specific parameters of the projection system in Example 1 are shown in Tables 1 and 2. The focal length of the optical system is 3.2mm, the maximum field of view is 110°, and the distortion of the entire system has been corrected to be very small, less than 1%. Figure 3 At the same time, the entire system has a high resolution, see... Figure 4 .

[0070] Table 1

[0071]

[0072]

[0073] Where R represents the radius of curvature of the lens, d represents the lens thickness or air gap, nd represents the refractive index of the glass, and vd represents the Abbe number of the glass. All aspherical surfaces are even-order aspherical surfaces, and their expressions are as follows:

[0074]

[0075] Where z is the sag of the vertex of the aspherical surface along the optical axis at a height of r, c represents the vertex curvature of the surface, k is the conic coefficient of the aspherical surface, and α2, α3, α4, α5, α6, α7, and α8 are higher-order aspherical coefficients.

[0076] Table 2

[0077]

[0078] Example 2

[0079] In Embodiment 2, from the object side to the image side, the lens groups are arranged as follows: a first lens group (G1), a second lens group (G2), and a third lens group (G3). The first lens group (G1) includes an eleventh lens (L11) and a twelfth lens (L12). The eleventh lens (L11) is a meniscus negative power aspherical lens with an Abbe number between 40 and 60, and the twelfth lens (L12) is also a meniscus negative power lens. The second lens group (G2) includes thirteenth to sixteenth lenses (L16). The thirteenth lens (L13) with biconcave negative power, the fourteenth lens (L14) with biconvex positive power, and the fifteenth lens (L15) with meniscus negative power form a cemented three-layer lens. The sixteenth lens (L16) is a biconvex positive power aspherical lens. The third lens group (G3) includes the seventeenth lens (L17) to the twenty-second lens (L22). The seventeenth lens (L17) with biconcave negative power and the eighteenth lens (L18) with biconvex positive power form a cemented lens. The nineteenth lens (L19) is a biconvex aspherical lens with positive power and an Abbe number between 55 and 90. The twentieth lens (L20) with biconcave negative power and the twenty-first lens (L21) with biconvex positive power form a cemented lens. The twenty-second lens (L22) is a biconvex aspherical lens with positive power and an Abbe number between 55 and 90.

[0080] The specific parameters of the projection system in Example 1 are shown in Tables 3 and 4. The optical system in Example 2 has a focal length of 2.0 mm and a maximum field of view of 120°. The distortion of the entire system has been corrected to be very small, less than 1%. Figure 6 At the same time, the entire system has a high resolution, see... Figure 7 .

[0081] Table 3

[0082] Face number face shape R d nd vd 1 aspherical 66.2 2.41 1.51 56.5 2 aspherical 6.83 6.41 3 spherical 21.42 0.9 1.91 35.3 4 spherical 5.66 4.68 5 spherical -12.8 2.5 1.77 49.6 6 spherical 5.7 2.51 1.72 29.5 7 spherical -3.78 0.5 2.00 29.1 8 spherical -66.9 0.15 9 aspherical 16.2 2.41 1.69 31.2 10 aspherical -8.55 1 11 spherical Infinity 1.48 12 spherical -32.13 0.5 2.00 29.1 13 spherical 5.66 2.4 1.95 17.9 14 spherical -364 0.15 15 aspherical 8.6 3.19 1.49 70.4 16 aspherical -6.68 0.15 17 spherical -13.69 0.5 2.00 25.5 18 spherical 6.94 3.69 1.59 67.3 19 spherical -12.39 0.15 20 aspherical 16.7 4.32 1.50 81.6 21 aspherical -8.44 4.76 22 spherical Infinity 9.2 1.74 44.9 23 spherical Infinity 1

[0083] Where R represents the radius of curvature of the lens, d represents the lens thickness or air gap, nd represents the refractive index of the glass, and vd represents the Abbe number of the glass. All aspherical surfaces are even-order aspherical surfaces, and their expressions are as follows:

[0084]

[0085] Where z is the sag of the vertex of the aspherical surface along the optical axis at a height of r, c represents the vertex curvature of the surface, k is the conic coefficient of the aspherical surface, and α2, α3, α4, α5, α6, α7, and α8 are higher-order aspherical coefficients.

[0086] Table 4

[0087]

[0088]

[0089] Implementing the embodiments of the present invention has the following beneficial effects: In this embodiment, the micro-projection lens includes a first lens group, a second lens group, and a third lens group from the object side to the image side. The first lens group includes at least one aspherical lens, the second lens group includes at least one aspherical lens, and the third lens group includes at least one aspherical lens and a set of cemented lenses. The first lens group reduces distortion aberrations, the second lens group reduces spherical aberration and shrinks the projection size, and the third lens group reduces chromatic aberration. Through the cooperation between the lens groups, it has the characteristics of fewer lenses and simple structure, and can significantly reduce the size and weight of the lens and reduce the lens cost. While improving geometric efficiency, it has high projection quality, low image distortion, and can support 4K resolution.

[0090] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A miniature projection lens, characterized in that, From the object side to the image side, the lens group comprises a first lens group, a second lens group, and a third lens group in sequence; the first lens group includes at least one aspherical lens, the second lens group includes at least one aspherical lens, and the third lens group includes at least one aspherical lens and a set of cemented lenses; The first lens group is used to reduce distortion aberrations; The second lens group is used to reduce spherical aberration and decrease the projected size; The third lens group is used to reduce chromatic aberration; The first lens group includes a first lens and a second lens, both of which are meniscus lenses; the second lens group includes a third to a sixth lens, the third lens being a biconcave lens, the fourth lens being a meniscus lens, and the fifth and sixth lenses both being biconvex lenses, the fourth and fifth lenses forming a first cemented lens; the third lens group includes a seventh, an eighth, and a ninth lens, the seventh and ninth lenses both being biconvex lenses, the eighth lens being a meniscus lens, and the seventh and eighth lenses forming a second cemented lens; Alternatively, the first lens group includes an eleventh lens and a twelfth lens, both of which are meniscus lenses; the second lens group includes thirteenth to sixteenth lenses, the thirteenth lens being a biconcave lens, the fourteenth and sixteenth lenses both being biconvex lenses, and the fifteenth lens being a meniscus lens, the thirteenth, fourteenth, and fifteenth lenses forming a third cemented lens; the third lens group includes seventeenth to twenty-second lenses, the seventeenth and twentieth lenses both being biconcave lenses, the eighteenth, nineteenth, twenty-first, and twenty-second lenses being biconvex lenses, the seventeenth and eighteenth lenses forming a fourth cemented lens, and the twentieth and twenty-first lenses forming a fifth cemented lens.

2. The miniature projection lens according to claim 1, characterized in that, The focal length of the micro-projection lens and the length of the projection lens satisfy the following relationship: 0.05 <f / L<0.07 Where f represents the focal length of the micro-projection lens, and L represents the length of the micro-projection lens.

3. The miniature projection lens according to claim 1, characterized in that, The focal length of the micro-projection lens and the focal length of the first lens group satisfy the following relationship: -0.6 <f / f1<-0.3 Where f represents the focal length of the micro-projection lens, and f1 represents the focal length of the first lens group.

4. The miniature projection lens according to claim 1, characterized in that, The focal lengths of the first lens group and the second lens group satisfy the following relationship: -0.7 <f1 / f2<-0.3 Where f1 represents the focal length of the first lens group and f2 represents the focal length of the second lens group.

5. The miniature projection lens according to claim 1, characterized in that, The focal lengths of the first lens group and the third lens group satisfy the following relationship: -0.9 <f1 / f3<-0.6 Where f1 represents the focal length of the first lens group and f3 represents the focal length of the third lens group.

6. The miniature projection lens according to claim 1, characterized in that, The first lens group contains at least one aspherical lens with an Abbe number between 40 and 60.

7. The miniature projection lens according to claim 1, characterized in that, The Abbe number of at least one aspherical lens in the third lens group is between 55 and 90.

8. A projection system comprising a prism and a miniature projection lens as described in any one of claims 1-7.

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