Miniaturized projection lens and imaging device

Abstract

The invention relates to the field of optics, in particular to a miniaturized projection lens and an imaging device.The miniaturized projection lens is sequentially composed of a fixed lens group with negative focal power, a refraction assembly, a zoom lens group with positive focal power and a focusing lens group with positive focal power from the object plane side to the image plane side; the zoom lens group and the focusing lens group move along the main optical axis direction of the miniaturized projection lens; the miniaturized projection lens satisfies the following conditional expressions: TTL / fw is less than 20; xG3 / fw < 2; wherein TTL is the total optical length of the miniaturized projection lens, fw is the focal length of the miniaturized projection lens in a wide-angle state, and XG3 is the maximum moving distance of the zoom lens group. Through the arrangement of the refraction assembly, on the basis of not changing the total optical length of the miniaturized projection lens, a part of the total optical length is bent, so that the axial physical length of the miniaturized projection lens is reduced, and the miniaturized projection lens is convenient to install.

Description

Technical Field

[0001] This invention relates to the field of optics, specifically to a miniaturized projection lens and imaging device. Background Technology

[0002] Miniaturized projection lenses, also known as projector lenses, are the core optical components of projectors. Based on projection distance, they are categorized into short-throw, medium-throw, long-throw, and special types such as reflective and fisheye lenses, and are widely used in education, engineering, and home applications. Their core parameter, the throw ratio, is the ratio of projection distance to screen width. Short-throw lenses have a throw ratio of less than 1, while ultra-short-throw lenses can reach 0.25, enabling the projection of large images from short distances.

[0003] Currently, miniaturized projection lenses are mainly used indoors. In order to achieve a smaller transmittance, the number of lenses inside the miniaturized projection lens will be large, and the size of the miniaturized projection lens is still relatively large, making it difficult to meet the installation requirements of miniaturized projection lenses. Summary of the Invention

[0004] This invention addresses existing technical problems by providing a miniaturized projection lens and imaging device. By defining the structure and parameters described above and by setting up a refractive component, a portion of the total optical length of the miniaturized projection lens is bent without altering its overall optical length, thereby reducing the axial physical length of the miniaturized projection lens and facilitating its installation.

[0005] The technical solution provided by this invention is as follows:

[0006] A miniaturized projection lens, wherein the miniaturized projection lens is composed of a fixed lens group with negative optical power, a refractive component, a zoom lens group with positive optical power and a focusing lens group with positive optical power, from the object plane side to the image plane side.

[0007] The zoom lens group and the focusing lens group move along the main optical axis of the miniaturized projection lens;

[0008] The miniaturized projection lens satisfies the following condition:

[0009] TTL / fw < 20;

[0010] XG3 / fw < 2;

[0011] Wherein, TTL is the total optical length of the miniaturized projection lens, fw is the focal length of the miniaturized projection lens in wide-angle mode, and XG3 is the maximum moving distance of the zoom lens group.

[0012] By limiting the structure and parameters described above and by setting the refractive component, a portion of the total optical length of the miniaturized projection lens is bent without changing the overall optical length of the lens, thereby reducing the axial physical length of the miniaturized projection lens and facilitating its installation.

[0013] Preferably, the miniaturized projection lens satisfies the following condition:

[0014] ft / fw < 2;

[0015] Where ft is the focal length of the miniaturized projection lens in telephoto mode.

[0016] By limiting the focal length, the shooting range of the miniaturized projection lens is limited, further increasing the resolution of the miniaturized projection lens.

[0017] Preferably, the fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with negative optical power, a third fixed lens with negative optical power, a fourth fixed lens with positive optical power, a fifth fixed lens with negative optical power, and a sixth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0018] Preferably, the fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with negative optical power, a fourth fixed lens with positive optical power, a fifth fixed lens with negative optical power, and a sixth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0019] Preferably, the zoom lens group consists of a first zoom lens with positive optical power, a second zoom lens with negative optical power, a third zoom lens with negative optical power, and a fourth zoom lens with positive optical power, arranged sequentially from the object plane side to the image plane side, wherein the third zoom lens and the fourth zoom lens are cemented together.

[0020] Preferably, the focusing lens group consists of a first focusing lens with positive optical power, a second focusing lens with positive optical power, and a third focusing lens with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0021] Preferably, the radial radii of the first fixed lens to the sixth fixed lens gradually decrease.

[0022] In this technical solution, by limiting the radial radius of the first fixed lens to the sixth fixed lens, the physical structure of the miniaturized projection lens is optimized, and at the same time, the ultra-wide-angle effect of the miniaturized projection lens can be achieved, thereby increasing the field of view of the miniaturized projection lens.

[0023] Preferably, the miniaturized projection lens satisfies the following condition:

[0024] 0.8 < XG4 / XG3 < 1.2;

[0025] Wherein, XG4 is the maximum moving distance of the focusing lens group.

[0026] In this technical solution, by limiting the maximum moving distance of the focusing lens group, the aberrations and coma of the miniaturized projection lens are greatly reduced, and the resolving power of the zoom lens is increased.

[0027] Preferably, the miniaturized projection lens satisfies the following condition:

[0028] 5 < fG4 / fw < 7;

[0029] Wherein, fG4 is the focal length of the focusing lens group.

[0030] In this technical solution, by limiting the focal length of the focusing lens group, the moving distance of the focusing lens group and the total optical length are reduced, thereby achieving miniaturization of the projection lens.

[0031] One of the objectives of this invention is to provide an imaging device, comprising: a miniaturized projection lens; and an imaging element configured to receive an image formed by the miniaturized projection lens.

[0032] Compared with the prior art, the miniaturized projection lens and imaging device provided by the present invention have the following beneficial effects:

[0033] 1. By limiting the structure and parameters mentioned above and setting the refractive component, a portion of the total optical length of the miniaturized projection lens is bent without changing the total optical length of the lens, thereby reducing the axial physical length of the miniaturized projection lens and facilitating its installation.

[0034] 2. By limiting the radial radius of the first fixed lens to the sixth fixed lens, the physical structure of the miniaturized projection lens is optimized, and the ultra-wide-angle effect of the miniaturized projection lens can also be achieved, increasing the field of view of the miniaturized projection lens.

[0035] 3. By limiting the focal length of the focusing lens group, the moving distance of the focusing lens group and the total optical length are reduced, thus achieving miniaturization of the projection lens. Attached Figure Description

[0036] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of a miniaturized projection lens and imaging device.

[0037] Figure 1 This is a schematic diagram of the structure of a miniaturized projection lens according to the present invention;

[0038] Figure 2This is an aberration diagram of a miniaturized projection lens in wide-angle mode according to the present invention;

[0039] Figure 3 This invention relates to a coma diagram of a miniaturized projection lens in a wide-angle state.

[0040] Figure 4 This is an aberration diagram of a miniaturized projection lens in telephoto mode according to the present invention;

[0041] Figure 5 This invention provides a coma diagram of a miniaturized projection lens in telescopic mode.

[0042] Figure 6 This is a schematic diagram of another miniaturized projection lens according to the present invention;

[0043] Figure 7 This is another aberration diagram of the wide-angle state of the miniaturized projection lens of the present invention;

[0044] Figure 8 This is another coma diagram of the wide-angle state of the miniaturized projection lens of the present invention;

[0045] Figure 9 This is an aberration diagram of another miniaturized projection lens in telescopic mode according to the present invention;

[0046] Figure 10 This is another coma diagram of the telephoto state of a miniaturized projection lens according to the present invention.

[0047] Explanation of reference numerals: G1, Fixed lens group; G2, Refractive assembly; G3, Zoom lens group; G4, Focusing lens group; G5, Auxiliary assembly; a1, First fixed lens; a2, Second fixed lens; a3, Third fixed lens; a4, Fourth fixed lens; a5, Fifth fixed lens; a6, Sixth fixed lens; b1, First zoom lens; b2, Second zoom lens; b3, Third zoom lens; b4, Fourth zoom lens; c1, First focusing lens; c2, Second focusing lens; c3, Third focusing lens; STO, Aperture stop; P, Deflecting prism; CG1, First protective glass; CG2, Second protective glass. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0050] Example 1

[0051] like Figure 1 and Figure 6 As shown, a miniaturized projection lens is composed of a fixed lens group G1 with negative optical power, a refractive component G2, a zoom lens group G3 with positive optical power, and a focusing lens group G4 with positive optical power, from the object plane side to the image plane side; specifically, the refractive component G2 is an optical device such as a deflecting prism P or a reflector used to refract light.

[0052] The zoom lens group G3 and the focusing lens group G4 move along the main optical axis of the miniaturized projection lens.

[0053] The miniaturized projection lens satisfies the following condition:

[0054] TTL / fw < 20;

[0055] XG3 / fw < 2;

[0056] Wherein, TTL is the total optical length of the miniaturized projection lens, fw is the focal length of the miniaturized projection lens in wide-angle mode, and XG3 is the maximum moving distance of the zoom lens group G3.

[0057] In this embodiment, by limiting the structure and parameters described above and by setting the refractive component G2, a portion of the total optical length of the miniaturized projection lens is bent without changing the total optical length of the miniaturized projection lens, thereby reducing the physical length of the miniaturized projection lens along the axis and facilitating the installation of the miniaturized projection lens.

[0058] The miniaturized projection lens satisfies the following condition:

[0059] ft / fw < 2;

[0060] Where ft is the focal length of the miniaturized projection lens in telephoto mode.

[0061] In this embodiment, by limiting the focal length, the shooting range of the miniaturized projection lens is limited, further increasing the resolution of the miniaturized projection lens.

[0062] The fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with negative optical power, a third fixed lens a3 with negative optical power, a fourth fixed lens a4 with positive optical power, a fifth fixed lens a5 with negative optical power, and a sixth fixed lens a6 with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0063] Alternatively, the fixed lens group G1 may be composed of a first fixed lens a1 with negative optical power, a second fixed lens a2 with negative optical power, a fourth fixed lens a4 with positive optical power, a fifth fixed lens a5 with negative optical power, and a sixth fixed lens a6 with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0064] The zoom lens group G3 consists of a first zoom lens b1 with positive optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with negative optical power, and a fourth zoom lens b4 with positive optical power, arranged sequentially from the object plane side to the image plane side. The third zoom lens b3 and the fourth zoom lens b4 are cemented together.

[0065] The focusing lens group G4 consists of a first focusing lens c1 with positive optical power, a second focusing lens c2 with positive optical power, and a third focusing lens c3 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0066] The radial radii of the first fixed lens a1 to the sixth fixed lens a6 gradually decrease.

[0067] In this embodiment, by limiting the radial radii of the first fixed lens a1 to the sixth fixed lens a6, the physical structure of the miniaturized projection lens is optimized, and the ultra-wide-angle effect of the miniaturized projection lens can also be achieved, increasing the field of view of the miniaturized projection lens.

[0068] The miniaturized projection lens satisfies the following condition:

[0069] 0.8 < XG4 / XG3 < 1.2;

[0070] Wherein, XG4 is the maximum moving distance of the focusing lens group G4.

[0071] In this embodiment, by limiting the maximum moving distance of the focusing lens group G4, the aberrations and coma of the miniaturized projection lens are greatly reduced, and the resolving power of the zoom lens is increased.

[0072] The miniaturized projection lens satisfies the following condition:

[0073] 5 < fG4 / fw < 7;

[0074] Wherein, fG4 is the focal length of the focusing lens group G4.

[0075] By limiting the focal length of the focusing lens group G4, the moving distance of the focusing lens group G4 and the total optical length are reduced, thus achieving miniaturization of the projection lens.

[0076] Example 2

[0077] like Figures 1 to 5 As shown, a miniaturized projection lens is composed of a fixed lens group G1 with negative optical power, a refractive component G2, a zoom lens group G3 with positive optical power, a focusing lens group G4 with positive optical power, and an auxiliary component G5, arranged sequentially from the object plane side to the image plane side.

[0078] The fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with negative optical power, a third fixed lens a3 with negative optical power, a fourth fixed lens a4 with positive optical power, a fifth fixed lens a5 with negative optical power, and a sixth fixed lens a6 with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0079] The zoom lens group G3 consists of a first zoom lens b1 with positive optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with negative optical power, and a fourth zoom lens b4 with positive optical power, arranged sequentially from the object plane side to the image plane side. The third zoom lens b3 and the fourth zoom lens b4 are cemented together.

[0080] The focusing lens group G4 consists of a first focusing lens c1 with positive optical power, a second focusing lens c2 with positive optical power, and a third focusing lens c3 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0081] The auxiliary component G5 consists of a first protective glass CG1 and a second protective glass CG2, arranged sequentially from the object plane side to the image plane side.

[0082] The basic lens data of the miniaturized projection lens of this embodiment is shown in Table 1, the variable parameters in Table 1 are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0083] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0084] In Table 2, the WIDE column indicates the specific values ​​of each variable parameter when the miniaturized projection lens is in the wide-angle end state, and the TELE column indicates the specific values ​​of each variable parameter when the miniaturized projection lens is in the telephoto end state.

[0085] In Table 3, K is the conic coefficient, and e is the scientific notation, for example, e-005 represents 10. -5 .

[0086] Table 1

[0087]

[0088]

[0089] Table 2

[0090] Wide TELE D1 3.44 0.1 D2 0.1 0.39 D3 0.74 3.79

[0091] Table 3

[0092]

[0093] In this embodiment, fw = 2.29 mm, ft = 4.08 mm, fno = 2.3~4.1, TTL = 33.84 mm, TTL / fw = 14.78, ft / fw = 1.78;

[0094] Wherein, TTL is the total optical length of the miniaturized projection lens, fno is the aperture number of the miniaturized projection lens, and fw is the focal length of the miniaturized projection lens in wide-angle mode.

[0095] XG3=3.34mm, XG3 / fw=1.46;

[0096] Wherein, XG3 is the maximum moving distance of the zoom lens group G3.

[0097] XG4=3.05mm, XG4 / XG3=0.91;

[0098] Wherein, XG4 is the maximum moving distance of the focusing lens group G4.

[0099] fG4=13.71mm, fG4 / fw=5.99;

[0100] Wherein, fG4 is the focal length of the focusing lens group G4.

[0101] Example 3

[0102] like Figures 6 to 10As shown, a miniaturized projection lens is composed of a fixed lens group G1 with negative optical power, a refractive component G2, a zoom lens group G3 with positive optical power, a focusing lens group G4 with positive optical power, and an auxiliary component G5, arranged sequentially from the object plane side to the image plane side.

[0103] The fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with negative optical power, a fourth fixed lens a4 with positive optical power, a fifth fixed lens a5 with negative optical power, and a sixth fixed lens a6 with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0104] The zoom lens group G3 consists of a first zoom lens b1 with positive optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with negative optical power, and a fourth zoom lens b4 with positive optical power, arranged sequentially from the object plane side to the image plane side. The third zoom lens b3 and the fourth zoom lens b4 are cemented together.

[0105] The focusing lens group G4 consists of a first focusing lens c1 with positive optical power, a second focusing lens c2 with positive optical power, and a third focusing lens c3 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0106] The auxiliary component G5 consists of a first protective glass CG1 and a second protective glass CG2, arranged sequentially from the object plane side to the image plane side.

[0107] The basic lens data of the miniaturized projection lens in this embodiment is shown in Table 4, the variable parameters in Table 4 are shown in Table 5, and the aspherical coefficients are shown in Table 6.

[0108] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0109] In Table 5, the WIDE column indicates the specific values ​​of each variable parameter when the miniaturized projection lens is in the wide-angle end state, and the TELE column indicates the specific values ​​of each variable parameter when the miniaturized projection lens is in the telephoto end state.

[0110] In Table 6, K is the conic coefficient, and e is the scientific notation, for example, e-005 represents 10. -5 .

[0111] Table 4

[0112]

[0113]

[0114] Table 5

[0115] Wide TELE D1 3.64 0.1 D2 0.1 0.08 D3 1.08 4.64

[0116] Table 6

[0117]

[0118] In this embodiment, fw = 2.22mm, ft = 4.05mm, fno = 2.36~4.32, TTL = 34.49mm, TTL / fw = 15.54, ft / fw = 1.82;

[0119] Wherein, TTL is the total optical length of the miniaturized projection lens, fno is the aperture number of the miniaturized projection lens, and fw is the focal length of the miniaturized projection lens in wide-angle mode.

[0120] XG3=3.54mm, XG3 / fw=1.59;

[0121] Wherein, XG3 is the maximum moving distance of the zoom lens group G3.

[0122] XG4=3.56mm, XG4 / XG3=1.006;

[0123] Wherein, XG4 is the maximum moving distance of the focusing lens group G4.

[0124] fG4=15.39mm, fG4 / fw=6.93;

[0125] Wherein, fG4 is the focal length of the focusing lens group G4.

[0126] Example 4

[0127] An imaging device, such as Figures 1 to 10 As shown, it includes: a miniaturized projection lens as described in any of the above embodiments, and an imaging element configured to receive an image formed by the miniaturized projection lens.

[0128] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A miniaturized projection lens, characterized in that, The miniaturized projection lens consists of a fixed lens group with negative optical power, a refractive component, a zoom lens group with positive optical power, and a focusing lens group with positive optical power, from the object plane side to the image plane side. The zoom lens group and the focusing lens group move along the main optical axis of the miniaturized projection lens; The miniaturized projection lens satisfies the following condition: TTL / fw < 20; XG3 / fw < 2; Wherein, TTL is the total optical length of the miniaturized projection lens, fw is the focal length of the miniaturized projection lens in wide-angle mode, and XG3 is the maximum moving distance of the zoom lens group.

2. The miniaturized projection lens according to claim 1, characterized in that: The miniaturized projection lens satisfies the following condition: ft / fw < 2; Where ft is the focal length of the miniaturized projection lens in telephoto mode.

3. A miniaturized projection lens according to claim 1, characterized in that: The fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with negative optical power, a third fixed lens with negative optical power, a fourth fixed lens with positive optical power, a fifth fixed lens with negative optical power, and a sixth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

4. A miniaturized projection lens according to claim 1, characterized in that: The fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with negative optical power, a fourth fixed lens with positive optical power, a fifth fixed lens with negative optical power, and a sixth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

5. A miniaturized projection lens according to claim 1, characterized in that: The zoom lens group consists of a first zoom lens with positive optical power, a second zoom lens with negative optical power, a third zoom lens with negative optical power, and a fourth zoom lens with positive optical power, arranged sequentially from the object plane side to the image plane side. The third zoom lens and the fourth zoom lens are cemented together.

6. A miniaturized projection lens according to claim 1, characterized in that: The focusing lens group consists of a first focusing lens with positive optical power, a second focusing lens with positive optical power, and a third focusing lens with negative optical power, arranged sequentially from the object plane side to the image plane side.

7. A miniaturized projection lens according to claim 3 or 4, characterized in that: The radial radii of the first fixed lens to the sixth fixed lens gradually decrease.

8. A miniaturized projection lens according to claim 1, characterized in that: The miniaturized projection lens satisfies the following condition: 0.8 < XG4 / XG3 < 1.2; Wherein, XG4 is the maximum moving distance of the focusing lens group.

9. A miniaturized projection lens according to claim 1, characterized in that: The miniaturized projection lens satisfies the following condition: 5 < fG4 / fw < 7; Wherein, fG4 is the focal length of the focusing lens group.

10. An imaging device, characterized in that, include: The miniaturized projection lens as described in any one of claims 1 to 9; An imaging element is configured to receive an image formed by the miniaturized projection lens.

Images