Continuous zooming projection lens

Abstract

The embodiment of the utility model discloses a continuous zooming projection lens. Comprising a first fixed lens group with negative focal power, a zoom lens group with positive focal power, a second fixed lens group with negative focal power, a focusing lens group with positive focal power, a third fixed lens group with positive focal power, galvanometer glass, a beam splitter prism and protective glass which are coaxially arranged and sequentially arranged from an object plane side to an image plane side, an imaging plane; and a diaphragm is arranged between the second fixed lens group and the focusing lens group. By implementing the projection lens provided by the embodiment of the utility model, the condition that the projection lens needs to be frequently switched among different application scenes can be realized, not only are the flexibility and applicability improved, but also the design, material and storage costs can be effectively reduced, and the tedious process of replacing the lens can be reduced, so that the requirements of different users and application scenes can be better met.

Description

Technical Field

[0001] The utility model relates to the technical field of projection lenses, in particular to a continuous zoom projection lens. Background Art

[0002] The projection lens is the core component of the projection device. It projects light onto the projection screen through a reflective or projected light modulator to form an image. Currently, the projection technologies on the market are mainly divided into LCD, DLP and LCOS projectors. LCD projectors have quickly occupied the low-end and mid-end market with their mature technology and low cost.

[0003] With the popularity of projection equipment, the technical requirements for projectors are becoming more and more diverse, such as smaller image distortion, clearer image quality, larger projection image size and smaller projection ratio. Especially in scenes that require a high off-axis rate, projectors can be flexibly placed on various platforms without being affected by space restrictions.

[0004] At present, DLP projectors on the market usually use fixed-focus lenses. However, fixed-focus lenses cannot meet the needs of short focus and long focus at the same time. Fixed-specification fixed-focus lenses are only suitable for specific application scenarios, and as the application scenarios change, fixed-focus lenses of different specifications may need to be replaced, which will increase design, material and storage costs. In addition, once the lens is assembled with the whole machine, it is relatively cumbersome to replace the lens again. In some special scenarios, such as in-vehicle assisted driving, a smaller projection object distance can ensure a greater illumination concentration effect, which is particularly important for selecting an appropriate projection lens.

[0005] Therefore, it is necessary to design a new lens that is suitable for situations where frequent switching between different application scenarios is required. This not only improves flexibility and applicability, but also effectively reduces design, material and storage costs, and reduces the tedious process of replacing lenses, thereby better meeting the needs of different users and application scenarios. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide a continuous zoom projection lens.

[0007] In order to solve the above technical problems, the purpose of the utility model is achieved through the following technical solutions: providing a continuous zoom projection lens, comprising: a first fixed lens group with negative optical focal length, a variable magnification lens group with positive optical focal length, a second fixed lens group with negative optical focal length, a focusing lens group with positive optical focal length, a third fixed lens group with positive optical focal length, a galvanometer glass, a dichroic prism, a protective glass, and an imaging surface, which are coaxially arranged and arranged in sequence from the object plane side to the image plane side; an aperture is arranged between the second fixed lens group and the focusing lens group.

[0008] A further technical solution is as follows: the first fixed lens group includes a first lens with negative optical power and a second lens with negative optical power which are arranged in sequence from the object plane side to the image plane side.

[0009] A further technical solution is as follows: the variable power lens group comprises a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power arranged in sequence from the object plane side to the image plane side; the fourth lens and the fifth lens are cemented together.

[0010] A further technical solution is as follows: the second fixed lens group includes a sixth lens with negative optical power and a seventh lens with positive optical power, which are arranged in sequence from the object plane side to the image plane side; the sixth lens and the seventh lens are glued together.

[0011] A further technical solution is: the focusing lens group includes an eighth lens with positive focal power, a ninth lens with negative focal power, a tenth lens with negative focal power, and an eleventh lens with positive focal power, which are arranged in sequence from the object plane side to the image plane side; the ninth lens and the tenth lens are glued together.

[0012] A further technical solution is as follows: the third fixed lens group includes a twelfth lens with negative focal power and a thirteenth lens with positive focal power, which are arranged in sequence from the object plane side to the image plane side.

[0013] A further technical solution is that the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are spherical lenses respectively.

[0014] A further technical solution is: the first lens and the thirteenth lens are aspherical lenses.

[0015] A further technical solution is: the imaging surface includes a 0.23-inch DMD element.

[0016] A further technical solution is as follows: the ratio of the combined focal length of the first fixed lens group to the combined focal length of the variable-power lens group is -0.5, and the total length of the first fixed lens group and the variable-power lens group is 26 mm.

[0017] The beneficial effects of the utility model compared with the prior art are as follows: the utility model is suitable for situations where frequent switching between different application scenarios is required through a coaxial arrangement and sequential arrangement from the object side to the image side of a first fixed lens group with negative optical focal length, a variable magnification lens group with positive optical focal length, a second fixed lens group with negative optical focal length, a focusing lens group with positive optical focal length, a third fixed lens group with positive optical focal length, a galvanometer glass, a dichroic prism, a protective glass, and an imaging surface, thereby not only improving flexibility and applicability, but also effectively reducing design, material and storage costs, and reducing the tedious process of replacing lenses, thereby better meeting the needs of different users and application scenarios.

[0018] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic structural diagram of a continuous zoom projection lens provided by an embodiment of the utility model;

[0021] Figure 2 A schematic diagram of the displacement of a continuous zoom projection lens provided by an embodiment of the utility model Figure 1 ;

[0022] Figure 3 A schematic diagram of the displacement of a continuous zoom projection lens provided by an embodiment of the utility model Figure 2 ;

[0023] Figure 4 A schematic diagram of the MTF of a continuous zoom projection lens in a short-focus state provided by an embodiment of the utility model;

[0024] Figure 5 A schematic diagram of the MTF of a continuous zoom projection lens in a telephoto state provided by an embodiment of the utility model;

[0025] Figure 6 A field curvature evaluation diagram of a continuous zoom projection lens in a short-focus state provided by an embodiment of the utility model;

[0026] Figure 7 A distortion evaluation diagram of a continuous zoom projection lens in a short-focus state provided by an embodiment of the utility model;

[0027] Figure 8A field curvature evaluation diagram of a continuous zoom projection lens in a telephoto state provided by an embodiment of the utility model;

[0028] Fig. 9 A distortion evaluation diagram of a continuous zoom projection lens in a telephoto state provided by an embodiment of the utility model;

[0029] Fig.10 A schematic diagram of relative illumination of a continuous zoom projection lens in a short-focus state provided by an embodiment of the utility model;

[0030] Fig.11 A schematic diagram of relative illumination of a continuous zoom projection lens in a telephoto state provided by an embodiment of the utility model;

[0031] Description of the symbols in the figure:

[0032] Q1, first fixed lens group; Q2, variable power lens group; Q3, second fixed lens group; Q4, focusing lens group; Q5; third fixed lens group; 1, galvanometer glass; 2, dichroic prism; 3, protective glass; 4, imaging surface; G1, first lens; G2, second lens; G3, third lens; G4, fourth lens; G5, fifth lens; G6, sixth lens; G7, seventh lens; G8, eighth lens; G9, ninth lens; G10, tenth lens; G11, eleventh lens; G12, twelfth lens; G13, thirteenth lens. DETAILED DESCRIPTION

[0033] 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 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.

[0034] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0035] It should also be understood that the terms used in this utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in this utility model specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0036] It should be further understood that the term “and / or” used in the present specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0037] See also Figure 1 , Figure 1 A schematic structural diagram of a continuous zoom projection lens provided for an embodiment of the utility model. The projection lens can be used in projection scenes. By matching a 0.23-inch DMD chip, the off-axis rate is 100%, and clear imaging can be performed within 2-10 meters. The lens focal length can be continuously zoomed within the range of 7mm-14mm. It has higher practical value. It fills the gap that it is difficult to match an optical zoom lens with a telephoto projection system. It comprehensively considers and balances manufacturing, cost, image quality, projection brightness, etc., and has a series of advantages such as high imaging quality, small distortion, reasonable tolerance, and low cost.

[0038] See also Figure 1 A continuous zoom projection lens comprises: a first fixed lens group Q1 with negative optical power, a variable power lens group Q2 with positive optical power, a second fixed lens group Q3 with negative optical power, a focusing lens group Q4 with positive optical power, a third fixed lens group Q5 with positive optical power, a galvanometer glass 1, a beam splitter prism 2, a protective glass 3, and an imaging surface 4, which are coaxially arranged and arranged in sequence from the object plane side to the image plane side; an aperture stop STO is arranged between the second fixed lens group Q3 and the focusing lens group Q4.

[0039] In this embodiment, the zoom lens group Q2 and the focusing lens group Q4 move along the main optical axis direction of the zoom lens.

[0040] In one embodiment, see Figure 1 The first fixed lens group Q1 includes a first lens G1 with negative refractive power and a second lens G2 with negative refractive power, which are sequentially arranged from the object plane side to the image plane side.

[0041] In one embodiment, see Figure 1 The above-mentioned variable power lens group Q2 includes a third lens G3 with positive focal power, a fourth lens G4 with negative focal power, and a fifth lens G5 with positive focal power, which are arranged in sequence from the object side to the image side; the fourth lens G4 and the fifth lens G5 are cemented together.

[0042] In one embodiment, see Figure 1 The second fixed lens group Q3 includes a sixth lens G6 with negative refractive power and a seventh lens G7 with positive refractive power, which are sequentially arranged from the object plane side to the image plane side; the sixth lens G6 and the seventh lens G7 are cemented together.

[0043] In one embodiment, see Figure 1 The focusing lens group Q4 includes an eighth lens G8 with positive refractive power, a ninth lens G9 with negative refractive power, a tenth lens G10 with negative refractive power, and an eleventh lens G11 with positive refractive power, which are arranged in sequence from the object plane side to the image plane side; the ninth lens G9 and the tenth lens G10 are cemented together;

[0044] In one embodiment, see Figure 1 The third fixed lens group Q5 includes a twelfth lens G12 with negative refractive power and a thirteenth lens G13 with positive refractive power, which are arranged in sequence from the object plane side to the image plane side.

[0045] In one embodiment, see Figure 1 The second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11 and the twelfth lens G12 are spherical lenses respectively.

[0046] In one embodiment, see Figure 1 The first lens G1 and the thirteenth lens G13 are aspherical lenses. While correcting the aberration, the incident angle of the main ray of each field of view is guaranteed to be completely matched with the light cone angle and angular vector of the image source, thereby improving the image quality and efficiency of the entire imaging system. The CRA range is within ±2.5°. CRA refers to the angle between the main ray and the image plane.

[0047] In one embodiment, see Figure 1 The first lens G1 and the thirteenth lens G13 are made of plastic, and the other lenses are made of glass.

[0048] In this embodiment, the air space between the second lens G2 and the third lens G3, the air space between the fifth lens G5 and the sixth lens G6, the air space between the seventh lens G7 and the eighth lens G8, and the air space between the eleventh lens G11 and the twelfth lens G12 are all variable. Figure 2 As shown, the interval can be changed to switch the lens between short focus and long focus state.

[0049] In this embodiment, the above-mentioned continuous zoom projection lens satisfies the following conditional formula: ft / fw>2; TTL<70mm; wherein ft is the focal length of the continuous zoom projection lens in the telephoto state, fw is the focal length of the continuous zoom projection lens in the short focal state, and TTL is the total optical length of the continuous zoom projection lens;

[0050] In one embodiment, the imaging surface 4 includes a 0.23-inch DMD element.

[0051] In one embodiment, the ratio of the combined focal length of the first fixed lens group Q1 to the combined focal length of the variable power lens group Q2 is -0.5, and the total length of the first fixed lens group Q1 and the variable power lens group Q2 is 26 mm.

[0052] Specific parameters of the objective lens system formed by the continuous zoom projection lens of this embodiment are shown in Table 1 and Table 2.

[0053] Table 1. Specific parameters of objective lens system

[0054]

[0055]

[0056] Table 2. Specific parameters of objective lens system

[0057]

[0058] The variable spacing values ​​of the zoom lens are shown in Table 3.

[0059] Table 3. The variable spacing values ​​of the zoom lens are shown in the following table

[0060]

[0061] See also Figure 4 and Figure 5 The MTF (Modulation Transfer Function) index is currently the most accurate and scientific evaluation standard for lenses. The vertical axis represents contrast. The closer it is to 1, the better the lens imaging. The horizontal axis represents resolution, and the unit is line pairs per millimeter. The 0.23-inch DMD image source used in this embodiment has a pixel size of 5.4um, and the corresponding design resolution is 93 line pairs per millimeter. Projection lenses generally require that the MTF value of each field of view is at least 0.3 in the design, and the MTF value of each field of view in this embodiment is above 0.4.

[0062] See also Figures 6 to 9 , the ordinate represents the field of view angle of the lens. The abscissa of the field curvature graph represents the magnitude of the field curvature value, and the abscissa of the distortion graph represents the amount of distortion. Distortion is a very important indicator of a projection lens; the system distortion of the embodiment of the present application is within 1%.

[0063] See also Fig.10 and Fig.11Relative illumination refers to the ratio of the illumination at different coordinate points on the image plane to the illumination at the center point. The ordinate represents the normalized illumination value, and the abscissa represents the field of view angle of the lens. Under the same conditions, a smooth transition of the relative illumination curves of each field of view represents uniform illumination within the projection frame. The closer the relative illumination value of each field of view is to 1, the higher the final projection brightness. For general consumer projection lenses, a relative illumination greater than 0.6 can well meet people's usage needs.

[0064] In this embodiment, the projection ratio range of the continuous zoom projection lens is 1 to 2; the effective focal length range of the continuous zoom projection lens is 7 mm to 14; the continuous zoom projection lens adopts a 0.23-inch DMD element; the offset of the continuous zoom projection lens is 100%; the continuous zoom projection lens adopts a Fresnel film, which can effectively converge the main light angle of the lens.

[0065] The distortion of the continuous zoom projection lens of this embodiment is within 1%, achieving a low distortion effect; the working distance is in the range of 2-10 meters; the relative illumination of the full field of view is higher than 0.75%, the full field of view MTF is higher than 0.4, and the imaging quality is excellent; the distortion can be within 1%, and the distortion correction is excellent. Most of the lenses of the continuous zoom projection lens are made of glass material, which can effectively avoid the problem of serious focus deviation caused by the easy heat absorption of plastic aspherical surfaces, and has good resistance to temperature influence.

[0066] In this embodiment, the first lens G1 uses a high-refractive-index meniscus lens, which can effectively reduce the height of the light beam and has a significant effect on correcting distortion and reducing the aperture of subsequent lenses.

[0067] The spot radius of the continuous zoom projection lens (<4um) is smaller than the pixel size (5.4um), which has obvious advantages for projection display applications that focus on spot size and energy concentration.

[0068] The lens material selected for the continuous zoom projection lens has a high transmittance for light with a wavelength of 459-618nm, all exceeding 95% / 10mm. The energy absorption of the entire imaging system is relatively small, which can not only improve the overall brightness, but also reduce the heat generation of the system, reduce the power and size of the heat dissipation device, and contribute to the stability of the projection imaging.

[0069] The wavelengths of the continuous zoom projection lens are 459nm, 536nm, and 618nm, which include the wavelength fluctuations of actual visible light sources, making the lens design more in line with actual conditions.

[0070] The continuous zoom projection lens of this embodiment adopts a combination of glass lens and plastic lens, and the thickness of each lens does not exceed 6mm. The overall system length is small and controlled within 70mm.

[0071] In this embodiment, the continuous zoom projection lens satisfies the following conditional formula: 15 < TL / IH < 20, where TL represents the overall optical length of the continuous zoom projection lens, and IH represents the actual semi-image height of the continuous zoom projection lens.

[0072] When 15 < TL / IH < 20, the relationship between the overall length of the lens and the resolution ability can be reasonably balanced. When the value of TL / IH exceeds the upper limit, the overall length of the lens is too large, or in other words, if the overall length is shortened, the image height will be insufficient; when the value of TL / IH exceeds the lower limit, due to the excessive optical power of each lens, it is difficult to correct the lens aberration, and the resolution ability will decrease significantly.

[0073] In this embodiment, the continuous zoom projection lens satisfies the following conditional formula: 0.5 < IH / tanθ < 2; where IH represents the actual semi-image height of the continuous zoom projection lens, and θ represents the semi-field angle of the continuous zoom projection lens.

[0074] When 0.5 < IH / tanθ < 2, the distortion of the optical lens can be reasonably limited, and the difficulty of distortion correction can be reduced. When the value of IH / tanθ exceeds the lower limit, the distortion of the lens will increase in the negative direction; when the value of IH / tanθ exceeds the upper limit, the distortion of the lens will increase in the positive direction.

[0075] In this embodiment, the continuous zoom projection lens satisfies the following conditional formulas: 1.44 < Nd1 < 1.8; 15 < Vd1 < 30; where Nd1 represents the refractive index of the first lens G1, and Vd1 represents the dispersion coefficient of the first lens G1.

[0076] When 1.44 < Nd1 < 1.8; 15 < Vd1 < 30, the selection of the glass material of the first lens G1 can be reasonably limited, the aberration of other optical lenses can be balanced, and the beam height can be effectively reduced, which has a great effect on correcting distortion and reducing the aperture of subsequent lenses.

[0077] In this embodiment, the continuous zoom projection lens satisfies the following conditional formula: CRA < 2.5°; where CRA represents the principal ray incident angle of the continuous zoom projection lens on the imaging surface 4. When CRA < 2.5°, it can well match image sources such as DMD chips or LEDs to achieve a good projection effect.

[0078] In this embodiment, the lens curvature radii of the eighth lens G8 and the ninth lens G9 are arranged as positive, negative, negative, and positive, which can effectively control the smooth transition of light, thereby reducing the tolerance sensitivity of these two lenses, and further improving the actual production yield.

[0079] The above-mentioned continuous zoom projection lens is coaxially arranged and arranged in sequence from the object side to the image side, including a first fixed lens group Q1 with negative optical focal length, a variable magnification lens group Q2 with positive optical focal length, a second fixed lens group Q3 with negative optical focal length, a focusing lens group Q4 with positive optical focal length, a third fixed lens group Q5 with positive optical focal length, a galvanometer glass 1, a beam splitter prism 2, a protective glass 3, and an imaging surface 4. It is suitable for situations where frequent switching between different application scenarios is required, which not only improves flexibility and applicability, but also effectively reduces design, material and storage costs, and reduces the tedious process of replacing lenses, thereby better meeting the needs of different users and application scenarios.

[0080] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A continuous zoom projection lens, characterized in that: include: A first fixed lens group with negative optical focal length, a variable power lens group with positive optical focal length, a second fixed lens group with negative optical focal length, a focusing lens group with positive optical focal length, a third fixed lens group with positive optical focal length, a galvanometer glass, a dichroic prism, a protective glass, and an imaging surface are coaxially arranged and arranged in sequence from the object plane side to the image plane side; an aperture is arranged between the second fixed lens group and the focusing lens group.

2. The continuous zoom projection lens according to claim 1, characterized in that: The first fixed lens group includes a first lens with negative optical power and a second lens with negative optical power which are sequentially arranged from the object plane side to the image plane side.

3. The continuous zoom projection lens according to claim 2, characterized in that: The variable power lens group comprises a third lens with positive focal length, a fourth lens with negative focal length and a fifth lens with positive focal length, which are arranged in sequence from the object plane side to the image plane side; the fourth lens and the fifth lens are cemented together.

4. The continuous zoom projection lens according to claim 3, characterized in that: The second fixed lens group includes a sixth lens with negative optical power and a seventh lens with positive optical power which are sequentially arranged from the object plane side to the image plane side; the sixth lens and the seventh lens are cemented together.

5. The continuous zoom projection lens according to claim 4, characterized in that: The focusing lens group includes an eighth lens with positive focal power, a ninth lens with negative focal power, a tenth lens with negative focal power, and an eleventh lens with positive focal power, which are arranged in sequence from the object plane side to the image plane side; the ninth lens and the tenth lens are cemented together.

6. The continuous zoom projection lens according to claim 5, characterized in that: The third fixed lens group includes a twelfth lens with negative refractive power and a thirteenth lens with positive refractive power which are sequentially arranged from the object plane side to the image plane side.

7. The continuous zoom projection lens according to claim 6, characterized in that: The second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are spherical lenses respectively.

8. The continuous zoom projection lens according to claim 6, characterized in that: The first lens and the thirteenth lens are aspherical lenses.

9. The continuous zoom projection lens according to claim 1, characterized in that: The imaging surface includes a 0.23-inch DMD element.

10. The continuous zoom projection lens according to claim 1, characterized in that: The ratio of the combined focal length of the first fixed lens group to the combined focal length of the variable-power lens group is -0.5, and the total length of the first fixed lens group and the variable-power lens group is 26 mm.

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