Projection lens and projection equipment

Abstract

The utility model provides a projection lens and projection equipment, which are based on the technical field of optical imaging, and the projection lens is provided with an object side and an image side which are oppositely arranged along the direction of an optical axis. The projection lens comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with positive focal power and an image surface which are sequentially arranged from an object side to an image side, therefore, the image surface diameter of the projection lens is less than or equal to 7.54 mm, and the aperture value is between 2.2 and 2.6. Wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses. According to the scheme, the projection lens which is compact in structure, high in imaging quality, low in cost and low in temperature drift is realized by adopting the six spherical lenses and reasonably setting the focal power and the shape matching relation of each lens.

Description

Technical Field

[0001] The utility model relates to the technical field of optical imaging, in particular to a projection lens and a projection device. Background Art

[0002] With the development of projection technology in recent years, projection equipment has been widely used in industrial production and life-related products. Common projection equipment on the market is realized by direct projection. At present, it generally has the problem of not being able to take into account small size, low cost, high resolution, and no defocus at high temperature. For example, some lenses sacrifice part of the resolution or use plastic aspherical surfaces to reduce costs. However, due to the high heat generated by the projection equipment, such lenses are often prone to defocus due to high temperature, affecting the use effect; and some lenses have high imaging quality, but are expensive and are not recognized by the consumer market. Utility Model Content

[0003] The main purpose of the utility model is to provide a projection lens and a projection device, aiming to provide a projection lens with compact structure, low distortion, low cost and low temperature drift.

[0004] To achieve the above-mentioned object, the utility model provides a projection lens having an object side and an image side arranged opposite to each other along an optical axis direction, the projection lens comprising a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with positive optical power and an image plane, which are arranged in sequence from the object side to the image side, so that the image plane diameter of the projection lens is less than or equal to 7.54 mm, and the aperture value is between 2.2 and 2.6;

[0005] Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all spherical lenses.

[0006] In one embodiment, the projection lens further includes an aperture stop, and the aperture stop is disposed between the second lens and the third lens.

[0007] In one embodiment, the projection lens further includes a beam splitter prism and a protective glass which are sequentially arranged between the sixth lens and the image plane from the object side to the image side.

[0008] In one embodiment, the first lens is a meniscus lens, and its object-side surface is a convex surface;

[0009] The second lens is a concave-convex lens, and its object side surface is convex;

[0010] The third lens is a biconvex lens;

[0011] The fourth lens is a biconcave lens;

[0012] The fifth lens is a meniscus lens, and its object side surface is concave;

[0013] The sixth lens is a biconvex lens.

[0014] In one embodiment, the focal length of the projection lens is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6, wherein:

[0015] 13<f<14.5, 35<f1<45, -9.5<f2<-12, 9.5<f3<12, -9.5<f4<-12, 20<f5<25, 15.6<f6<17.5.

[0016] In one embodiment, the refractive index of the first lens is n1 and the dispersion coefficient is v1, the refractive index of the second lens is n2 and the dispersion coefficient is v2, the refractive index of the third lens is n3 and the dispersion coefficient is v3, the focal refractive index of the fourth lens is n4 and the dispersion coefficient is v4, the refractive index of the fifth lens is n5 and the dispersion coefficient is v5, and the refractive index of the sixth lens is n6 and the dispersion coefficient is v6, wherein:

[0017] 1.70≤n1≤2.00, 1.70≤n2≤2.00, 1.65≤n3≤2.00, 1.70≤n4≤2.00, 1.70≤n5≤2.00, 1.50≤n6≤1.80, 0<v1≤50.0, 0<v2≤50.0, 50.0≤v3, 0<v4≤50.0, 50.0≤v5, 50.0≤v6.

[0018] In one embodiment, the total optical length of the projection lens is TTL, and the effective focal length of the projection lens is f, wherein:

[0019] TTL / f≤4.5.

[0020] The utility model also provides a projection device, the projection device comprising the above-mentioned projection lens, the projection lens having an object side and an image side arranged opposite to each other along the optical axis direction, the projection lens comprising a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with positive optical power and an image plane arranged in sequence from the object side to the image side, so that the image plane diameter of the projection lens is less than or equal to 7.54 mm, and the aperture value is between 2.2 and 2.6;

[0021] Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all spherical lenses.

[0022] The technical solution provided by the utility model, by setting the sixth lens with positive optical power, bears a larger optical power of the system, changes the propagation direction of the light beam, corrects the aberration of the off-axis field of view, and is more conducive to the imaging of the light beam on the image plane; by setting other lenses as spherical lenses, the aberration is effectively improved, ensuring that it does not defocus under high temperature conditions; the light trend of the lens is smooth, and the structure is more compact while introducing more light, and the image plane diameter is controlled within 7.54mm. In terms of aperture, the aperture value F satisfies 2.0≤F≤2.6, the lens can also form a clear image in weak light, and by reasonably setting the focal length ratio, the lens has good heat elimination and more stable working performance. By using only six lenses and reasonably setting the optical power and shape matching relationship of each lens, a projection lens with compact structure, low distortion, low cost and low temperature drift is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0024] Figure 1 A schematic structural diagram of an embodiment of a projection lens provided by the utility model;

[0025] Figure 2 for Figure 1 MTF diagram of the projection lens;

[0026] Figure 3 for Figure 1 Relative illumination diagram of the projection lens;

[0027] Figure 4 for Figure 1 Schematic diagram of the field curvature distortion curve of the projection lens;

[0028] Figure 5 for Figure 1 Schematic diagram of the through-focus MTF of the projection lens;

[0029] Figure 6 A schematic structural diagram of another embodiment of the projection lens provided by the utility model;

[0030] Figure 7 for Figure 6 MTF diagram of the projection lens;

[0031] Figure 8 for Figure 6Relative illumination diagram of the projection lens;

[0032] Fig. 9 for Figure 6 Schematic diagram of the field curvature distortion curve of the projection lens;

[0033] Fig.10 for Figure 6 Schematic diagram of the through-focus MTF of the projection lens.

[0034] Description of Figure Numbers:

[0035] 1000. Projection lens; 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Aperture; 8. Beam splitter; 9. Protective glass; 10. Image plane.

[0036] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0039] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0040] With the development of projection technology in recent years, projection equipment has been widely used in industrial production and life-related products. Common projection equipment on the market is realized by direct projection. At present, it generally has the problem of not being able to take into account small size, low cost, high resolution, and no defocus at high temperature. For example, some lenses sacrifice part of the resolution or use plastic aspherical surfaces to reduce costs. However, due to the high heat generated by the projection equipment, such lenses are often prone to defocus due to high temperature, affecting the use effect; and some lenses have high imaging quality, but are expensive and are not recognized by the consumer market.

[0041] The main purpose of the utility model is to provide a projection lens and a projection device, aiming to provide a projection lens with compact structure, low distortion, low cost and low temperature drift.

[0042] See also Figure 1 The utility model proposes a projection lens 1000, which has an object side and an image side arranged opposite to each other along the optical axis direction. The projection lens 1000 includes a first lens 1 with positive optical power, a second lens 2 with negative optical power, a third lens 3 with positive optical power, a fourth lens 4 with negative optical power, a fifth lens 5 with positive optical power, a sixth lens 6 with positive optical power and an image plane 10, which are arranged in sequence from the object side to the image side, so that the image plane diameter of the projection lens 1000 is less than or equal to 7.54 mm, and the aperture value is between 2.2 and 2.6; wherein the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are all spherical lenses.

[0043] The technical solution provided by the utility model, by setting the sixth lens 6 with positive optical power, bears a larger optical power of the system, changes the propagation direction of the light beam, corrects the aberration of the off-axis field of view, and is more conducive to the imaging of the light beam on the image plane; by setting other lenses as spherical lenses, the aberration is effectively improved, ensuring that it does not defocus under high temperature conditions; the light trend of the lens is smooth, and the structure is more compact while introducing more light, and the image plane diameter is controlled within 7.54mm. In terms of aperture, the aperture value F satisfies 2.0≤F≤2.6, the lens can also form a clear image in weak light, and by reasonably setting the focal length ratio, the lens has good heat elimination and more stable working performance. By using only six lenses and reasonably setting the optical power and shape matching relationship of each lens, a projection lens 1000 with compact structure, low distortion, low cost and low temperature drift is realized.

[0044] Furthermore, the projection lens 1000 further includes an aperture 7, which is disposed between the second lens 2 and the third lens 3. The aperture limits the aperture of the light beam on the optical axis, intercepts part of the light, thereby reducing the light spot, improving the image contrast, and also expanding the target surface and improving the image quality. According to actual conditions, adjusting the light flux of the aperture 7 helps to further improve the imaging quality.

[0045] Furthermore, the projection lens 1000 further includes a beam splitter prism 8 and a protective glass 9 which are sequentially arranged between the sixth lens 6 and the image plane 10 from the object side to the image side. By providing the beam splitter prism 8, light can be effectively controlled and directed to ensure that the illuminated object or area can be properly illuminated. The protective glass 9 can play the role of waterproofing, dustproofing, and protecting the lens, thereby enhancing the anti-interference ability of the projection lens 1000 and improving the imaging quality.

[0046] Specifically, in two preferred embodiments, please refer to Figure 1 and Figure 6 The first lens 1 is a concave-convex lens, and its object side surface is convex; the second lens 2 is a concave-convex lens, and its object side surface is convex; the third lens 3 is a biconvex lens; the fourth lens 4 is a biconcave lens; the fifth lens 5 is a concave-convex lens, and its object side surface is concave; the sixth lens 6 is a biconvex lens.

[0047] Further, the focal length of the projection lens 1000 is f, the focal length of the first lens 1 is f1, the focal length of the second lens 2 is f2, the focal length of the third lens 3 is f3, the focal length of the fourth lens 4 is f4, the focal length of the fifth lens 5 is f5, and the focal length of the sixth lens 6 is f6, wherein: 13<f<14.5, 35<f1<45, -9.5<f2<-12, 9.5<f3<12, -9.5<f4<-12, 20<f5<25, 15.6<f6<17.5. This embodiment is a preferred embodiment, and through the mutual combination of different lenses and the reasonable allocation of their optical focal lengths, the entire lens has good performances such as low cost and high pixel.

[0048] Further, the refractive index of the first lens 1 is n1, and the dispersion coefficient is v1, the refractive index of the second lens 2 is n2, and the dispersion coefficient is v2, the refractive index of the third lens 3 is n3, and the dispersion coefficient is v3, the focal refractive index of the fourth lens 4 is n4, and the dispersion coefficient is v4, the refractive index of the fifth lens 5 is n5, and the dispersion coefficient is v5, and the refractive index of the sixth lens 6 is n6, and the dispersion coefficient is v6, wherein: 1.70≤n1≤2.00, 1.70≤n2≤2.00, 1.65≤n3≤2.00, 1.70≤n4≤2.00, 1.70≤n5≤2.00, 1.50≤n6≤1.80, 0<v1≤50.0, 0<v2≤50.0, 50.0≤v3, 0<v4≤50.0, 50.0≤v5, 50.0≤v6. This embodiment is a preferred embodiment. By combining different lenses and reasonably allocating their refractive indices and dispersion coefficients, the projection lens 1000 has low cost, high pixel count, and good athermal properties.

[0049] In an embodiment provided by the present invention, the total optical length of the projection lens 1000 is TTL, and the effective focal length of the projection lens 1000 is f, wherein: TTL / f≤4.5. By reasonably limiting the ratio of TTL to f, the entire lens is made more compact, and it is helpful to control the focal length of the projection lens 1000, which is conducive to miniaturization of the lens.

[0050] It should be noted that the basic parameter table of the projection lens 1000 in an embodiment provided by the present invention is shown in Table 1, wherein the units of the curvature radius, thickness and semi-diameter are all millimeters (mm).

[0051] Table 1

[0052]

[0053] Please refer to Figure 2 , is a schematic diagram of the MTF of the projection lens 1000 in this embodiment, which shows the imaging quality of several wavelengths of light, wherein the horizontal axis represents the number of line pairs, and the vertical axis represents the resolution capability, wherein the higher the value of the vertical axis, the stronger the resolution capability and the higher the image quality restoration degree, wherein the MTF values ​​are all greater than 0.6, indicating that the imaging quality is very clear.

[0054] Please refer to Figure 3 , is a relative illumination diagram of the projection lens 1000 in this embodiment, from Figure 3 It can be seen that under different fields of view, the relative illumination of the lens is above 0.9, which means that the distribution of lens illumination is relatively uniform and the details of all areas in the image can be properly displayed.

[0055] Please refer to Figure 4, is a schematic diagram of the field curvature distortion curve of the projection lens 1000 in this embodiment. Different colors represent different wavelengths. The right curve of the same color is the meridian direction, and the left curve is the sagittal field curvature. From the figure, the axial chromatic aberration is no more than 0.06mm, indicating that this lens can correct chromatic aberration well. The right curve in the figure is the distortion curve of the lens. The distortion does not affect the clarity of the system, but it will cause the image deformation of the system. The optical distortion of this system is less than 1%.

[0056] Please refer to Figure 5 , is a schematic diagram of the defocus of the projection lens 1000 in this embodiment, Figure 5 It can be seen that the defocus of this lens does not exceed 0.01mm, basically achieving the state of not defocusing at high and low temperatures.

[0057] In this embodiment, the focal length of the projection lens 1000 is 13.6 mm, the aperture value is 2.4, the image plane diameter is 7.54 mm, and the diagonal field angle is 31.1°, which ensures that various aberrations of the lens are corrected, improves edge image quality, has high imaging quality, and can produce clear images even in low light. The lens image plane diameter is small, and it does not defocus under environmental conditions of -40°C to +85°C, and still maintains good performance, and the working performance is relatively stable.

[0058] It should be noted that the basic parameter table of the projection lens 1000 in another embodiment provided by the present invention is shown in Table 2, wherein the units of the curvature radius, thickness and semi-diameter are all millimeters (mm).

[0059] Table 2

[0060]

[0061] Please refer to Figure 7 , is a schematic diagram of the MTF of the projection lens 1000 in this embodiment, which shows the imaging quality of several wavelengths of light, wherein the horizontal axis represents the number of line pairs, and the vertical axis represents the resolution capability, wherein the higher the value of the vertical axis, the stronger the resolution capability and the higher the image quality restoration degree, wherein the MTF values ​​are all greater than 0.6, indicating that the imaging quality is very clear.

[0062] Please refer to Figure 8 , is a relative illumination diagram of the projection lens 1000 in this embodiment, from Figure 8 It can be seen that under different fields of view, the relative illumination of the lens is above 0.9, which means that the distribution of lens illumination is relatively uniform and the details of all areas in the image can be properly displayed.

[0063] Please refer to Fig. 9, is a schematic diagram of the field curvature distortion curve of the projection lens 1000 in this embodiment. Different colors represent different wavelengths. The right curve of the same color is the meridian direction, and the left curve is the sagittal field curvature. From the figure, the axial chromatic aberration is no more than 0.05mm, indicating that this lens can correct chromatic aberration well. The right curve in the figure is the distortion curve of the lens. The distortion does not affect the clarity of the system, but it will cause the image of the system to deform. The optical distortion of this system is less than 1%.

[0064] Please refer to Fig.10 , is a schematic diagram of the defocus of the projection lens 1000 in this embodiment, Fig.10 It can be seen that the defocus of this lens does not exceed 0.01mm, basically achieving the state of not defocusing at high and low temperatures.

[0065] In this embodiment, the focal length of the projection lens 1000 is 13.6 mm, the aperture value is 2.4, the image plane diameter is 7.54 mm, and the diagonal field angle is 31.1°, which ensures that various aberrations of the lens are corrected, improves edge image quality, has high imaging quality, and can produce clear images even in low light. The lens image plane diameter is small, and it does not defocus under environmental conditions of -40°C to +85°C, and still maintains good performance, and the working performance is relatively stable.

[0066] The utility model further proposes a projection device, which includes the above-mentioned projection lens 1000. Since the projection device includes the projection lens 1000, the specific structure of the projection lens 1000 refers to the above-mentioned embodiment. Since the projection lens 1000 of the projection device adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0067] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A projection lens, characterized in that: The projection lens has an object side and an image side which are arranged opposite to each other along the optical axis direction, and the projection lens comprises a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens with positive optical power and an image plane which are arranged in sequence from the object side to the image side, so that the image plane diameter of the projection lens is less than or equal to 7.54 mm, and the aperture value is between 2.2 and 2.6; Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all spherical lenses.

2. The projection lens according to claim 1, wherein: The projection lens further includes an aperture stop, and the aperture stop is disposed between the second lens and the third lens.

3. The projection lens according to claim 1, wherein: The projection lens further includes a beam splitter prism and a protective glass which are sequentially arranged between the sixth lens and the image plane from the object side to the image side.

4. The projection lens according to claim 1, wherein: The first lens is a concave-convex lens, and its object side surface is convex; The second lens is a concave-convex lens, and its object side surface is convex; The third lens is a biconvex lens; The fourth lens is a biconcave lens; The fifth lens is a meniscus lens, and its object side surface is concave; The sixth lens is a biconvex lens.

5. The projection lens according to claim 4, wherein: The focal length of the projection lens is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6, wherein: 13<f<14.5, 35<f1<45, -9.5<f2<-12, 9.5<f3<12, -9.5<f4<-12, 20<f5<25, 15.6<f6<17.

5.

6. The projection lens according to claim 4, wherein: The refractive index of the first lens is n1, and the dispersion coefficient is v1; the refractive index of the second lens is n2, and the dispersion coefficient is v2; the refractive index of the third lens is n3, and the dispersion coefficient is v3; the focal refractive index of the fourth lens is n4, and the dispersion coefficient is v4; the refractive index of the fifth lens is n5, and the dispersion coefficient is v5; the refractive index of the sixth lens is n6, and the dispersion coefficient is v6, wherein: 1.70≤n1≤2.00, 1.70≤n2≤2.00, 1.65≤n3≤2.00, 1.70≤n4≤2.00, 1.70≤n5≤2.00, 1.50≤n6≤1.80, 0<v1≤50.0, 0<v2≤50.0, 50.0≤v3, 0<v4≤50.0, 50.0≤v5, 50.0≤v6.

7. The projection lens according to claim 1, wherein: The total optical length of the projection lens is TTL, and the effective focal length of the projection lens is f, wherein: TTL / f≤4.

5.

8. A projection device, characterized in that: Comprising the projection lens as claimed in any one of claims 1 to 7.

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