CN116841021B - Projection lens and projection device - Google Patents

Projection lens and projection device Download PDF

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Publication number
CN116841021B
CN116841021B CN202311123988.6A CN202311123988A CN116841021B CN 116841021 B CN116841021 B CN 116841021B CN 202311123988 A CN202311123988 A CN 202311123988A CN 116841021 B CN116841021 B CN 116841021B
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lens
projection
image
equal
less
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CN116841021A (en
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王志煌
李文宗
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Shenzhen Shengyang Optical Technology Co ltd
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Shenzhen Shengyang Optical Technology Co ltd
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/28—Reflectors in projection beam

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

The application relates to a projection lens and a projection device, wherein the projection lens comprises: refractive mirror group and reflecting mirror group; the reflecting mirror group comprises a first lens and a reflecting surface, and the reflecting surface is arranged at one side of the first lens far away from the refracting mirror group; the refractive lens group includes: a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, an aperture stop, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens; the first lens has positive optical power; the second lens has negative focal power; the third lens and the fourth lens have positive focal power; the fifth lens has negative focal power; the sixth lens and the seventh lens have positive focal power; the eighth lens and the ninth lens have negative focal power; the tenth lens, the eleventh lens and the twelfth lens have positive focal power; the separation distance T23 along the optical axis of the edge of the second lens and the edge of the third lens satisfies: t23 > 0.10mm.

Description

Projection lens and projection device
Technical Field
The present application relates to the field of optical elements, and more particularly, to a projection lens and a projection apparatus.
Background
In recent years, with the continuous development of technology and the rapid progress of technologies such as optoelectronics, mobile internet, and internet of things, electronic devices using projection lenses have been widely used in people's lives, for example, projectors, mobile phones, and car-mounted cameras. In a projection lens, a focal length is a very important index of the lens, and the size of the focal length of the lens determines the imaging size of a subject on an imaging medium. At present, a projection lens utilizes a short-focus and ultra-short-focus technology, and imaging quality of short focal distance is achieved by combining multiple lenses in a reflection mode. However, this will result in an excessively large lens assembly, and difficult assembly, thereby affecting ease of assembly and production yield of the projection lens.
Therefore, ensuring that the projection lens is easy to assemble and has good imaging quality on the basis of the short-focus or ultra-short-focus technology is a problem to be solved.
Disclosure of Invention
The application provides a projection lens, which sequentially comprises the following components along the transmission direction of an image beam: refractive mirror group and reflecting mirror group; the reflecting mirror group comprises a first lens and a reflecting surface, and the reflecting surface is arranged on one side of the first lens far away from the refracting mirror group; the refractive lens group includes: a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, an aperture stop, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens; the first lens has positive optical power; the second lens has negative optical power; the third lens and the fourth lens have positive focal power; the fifth lens has negative focal power; the sixth lens and the seventh lens have positive focal power; the eighth lens and the ninth lens have negative focal power; the tenth lens, the eleventh lens, and the twelfth lens have positive optical power; the distance T23 between the edge of the second lens and the edge of the third lens along the optical axis satisfies: t23 > 0.1mm.
In some embodiments, the separation distance T45 along the optical axis of the edge of the fourth lens and the edge of the fifth lens satisfies: t45 is more than or equal to 0 and less than or equal to 0.1mm.
In some embodiments, the separation distance T45 along the optical axis of the edge of the fourth lens and the edge of the fifth lens satisfies: t45=0.
In some embodiments, a separation distance L45 between a center of the fourth lens and a center of the fifth lens along the optical axis satisfies: l45 is more than or equal to T45, and L45 is more than or equal to 1.09mm and less than or equal to 3.87mm.
In some embodiments, the radius of curvature R42 of the image side of the fourth lens satisfies: 46.75mm < R42 > 106.53mm, and the curvature radius R51 of the object side surface of the fifth lens satisfies the following conditions: 21.71mm or less and R51 or less and 11.64mm or less.
In some embodiments, the radius of curvature R11 of the object-side surface of the first lens and the radius of curvature R12 of the image-side surface of the first lens satisfy: R11/R12 is more than or equal to 0.30mm and less than or equal to 0.64mm.
In some embodiments, the thickness of the first lens is greater than the thickness of the second lens in the direction of the optical axis.
In some embodiments, the first lens, the second lens, the sixth lens, and the twelfth lens are aspheric lenses.
In some embodiments, the effective focal length f of the refractive lens group t The method meets the following conditions: -f is less than or equal to 8.09mm t The effective focal length f of the reflecting mirror group is less than or equal to 7.01mm r The method meets the following conditions: -f is less than or equal to 8.57mm r ≤-7.95mm。
The application also provides a projection device, which can comprise an illumination system, a spatial light modulation system and the projection lens, wherein the illumination system is used for providing illumination light beams; the spatial light modulation system is configured on a transmission path of the illumination light beam and is used for modulating the illumination light beam into an image light beam; the projection lens is configured on the transmission path of the image light beam and is used for projecting the image light beam out of the projection device to form a projection picture, wherein the image light beam sequentially passes through the refraction mirror group and the reflection mirror group to form the projection picture.
The projection lens adopts a twelve-lens framework, and the focal power, the surface shape and the like of each lens group are reasonably distributed, so that the projection lens is easy to assemble and has at least one beneficial effect of good imaging quality and the like while meeting the requirement of forming a short focal length.
Drawings
Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:
fig. 1 shows a schematic configuration of a projection lens according to embodiment 1 of the present application;
fig. 2A to 2D show a longitudinal spherical aberration curve, an astigmatism curve, a distortion curve, and an MTF curve of the projection lens of embodiment 1, respectively;
fig. 3 is a schematic view showing the structure of a projection lens according to embodiment 2 of the present application;
fig. 4A to 4D show a longitudinal spherical aberration curve, an astigmatism curve, a distortion curve, and an MTF curve of the projection lens of embodiment 2, respectively;
fig. 5 shows a schematic structural view of a projection lens according to embodiment 3 of the present application;
fig. 6A to 6D show a longitudinal spherical aberration curve, an astigmatism curve, a distortion curve, and an MTF curve of the projection lens of embodiment 3, respectively;
fig. 7 is a schematic structural view of a projection apparatus 100 according to an exemplary embodiment of the present application.
Detailed Description
For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the application and is not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that in the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Accordingly, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present application.
In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.
Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side of the lens, and the surface of each lens closest to the imaging plane is referred to as the image side of the lens.
It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the application, use of "may" means "one or more embodiments of the application. Also, the term "exemplary" is intended to refer to an example or illustration.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
The features, principles, and other aspects of the present application are described in detail below.
The projection lens according to an exemplary embodiment of the present application may include twelve lenses, the lenses being sequentially arranged from an object side to an image side along an optical axis, an image beam being transmitted from the image side to the object side of the projection lens, the image beam transmitting direction sequentially including a refractive lens group and a reflective lens group, the reflective lens group including a first lens and a reflective surface, the reflective surface being disposed on a side of the first lens away from the refractive lens group, the refractive lens group sequentially including, in the image beam transmitting direction: a twelfth lens, an eleventh lens, a tenth lens, a ninth lens, an eighth lens, a seventh lens, a sixth lens, a fifth lens, a fourth lens, a third lens, and a second lens; any two adjacent lenses can be provided with an air space or can be glued.
In an exemplary embodiment, the projection lens may further include at least one aperture. The aperture may be provided at an appropriate position as required, for example, between the sixth lens and the seventh lens.
In an exemplary embodiment, the first lens has positive optical power; the second lens has negative focal power; the third lens and the fourth lens have positive focal power; the fifth lens has negative focal power; the sixth lens and the seventh lens have positive focal power; the eighth lens and the ninth lens have negative focal power; the tenth lens, the eleventh lens and the twelfth lens have positive focal power; the separation distance T23 along the optical axis between the edge of the second lens and the edge of the third lens satisfies: t23 > 0.10mm. In an exemplary embodiment, the separation distance T23 along the optical axis of the edge of the second lens and the edge of the third lens satisfies: t23 is more than or equal to 0.60mm and less than or equal to 3.00mm. The separation distance T45 along the optical axis between the edge of the fourth lens and the edge of the fifth lens satisfies: t45 is more than or equal to 0 and less than or equal to 0.1mm, so that the workability of the projection lens can be effectively improved, and the projection lens has good assembly easiness and yield. By way of example, T23 may be 0.10mm, 0.60mm, 0.70mm, 0.80mm, 0.90mm, 1.00mm, 1.5mm, 2.00mm, 2.50mm, 3.00mm.
In an exemplary embodiment, the separation distance T45 along the optical axis of the edge of the fourth lens and the edge of the fifth lens satisfies: t45=0, which is advantageous for correction of optical aberration between positive and negative lenses and for reduction of sensitivity to assembly tolerances.
In an exemplary embodiment, the separation distance L45 between the center of the fourth lens and the center of the fifth lens along the optical axis satisfies: l45 is more than or equal to T45, L45 is more than or equal to 1.09mm and less than or equal to 3.87mm, which is favorable for reducing the influence of the lens surface on the system aberration and obtaining better imaging quality. Illustratively, L45 may be 1.09mm, 1.37mm, 1.69mm, 3.22mm, 3.87mm.
In an exemplary embodiment, the radius of curvature R42 of the image side surface of the fourth lens satisfies: r42 is less than or equal to 46.75mm and less than or equal to 106.53mm, and the curvature radius R51 of the object side surface of the fifth lens meets the following conditions: r51 is less than or equal to 21.71mm and less than or equal to 11.64mm, which is favorable for correcting spherical aberration and astigmatism and improving the imaging quality of the system. Illustratively, R42 may be 46.75mm, 58.44mm, 83.63mm, 106.53mm. R51 may be-21.71 mm, -18.09mm, -17.02mm, -14.55mm, 11.64mm.
In an exemplary embodiment, the radius of curvature R11 of the object side surface of the first lens and the radius of curvature R12 of the image side surface of the first lens satisfy: R11/R12 is more than or equal to 0.30 and less than or equal to 0.64, which is favorable for correcting the spherical aberration and distortion of the lens and improving the resolving power of the system. Illustratively, the R11/R12 values may be 0.30, 0.37, 0.43, 0.54, 0.64.
In an exemplary embodiment, the thickness of the first lens is greater than the thickness of the second lens in the optical axis direction, which is advantageous in correcting spherical aberration of the system and ensuring manufacturability of the process.
In an exemplary embodiment, the effective focal length f of the refractive lens group t The method meets the following conditions: -f is less than or equal to 8.09mm t The effective focal length f of the reflector group is less than or equal to-7.01 mm r The method meets the following conditions: -f is less than or equal to 8.57mm r The lens is less than or equal to-7.95 mm, which is favorable for improving the optical aberration compensation and correction among lens groups and effectively improving the resolving power of the lens. Illustratively f t May be-8.09 mm, -7.80 mm, -7.60 mm, -7.40 mm, -7.20 mm, -7.01 mm; f (f) r May be-8.57 mm, -8.40 mm, -8.20 mm, -7.95 mm.
In an exemplary embodiment, the above-described projection lens may further include a filter for correcting color deviation and/or a protective glass for protecting the spatial light modulation system.
The projection lens according to the above embodiment of the present application may employ a plurality of lenses, for example twelve lenses, and by reasonably distributing the focal power, surface shape, etc. of each lens, the volume of the projection lens may be effectively reduced, the sensitivity of the projection lens may be reduced, and the workability of the projection lens may be improved, so that the projection lens may be more advantageous for production and processing and may be suitable for use in portable electronic products. The projection lens according to the embodiment of the application also has the characteristic of achieving a short focal length while meeting imaging requirements.
In an embodiment of the present application, the first lens, the second lens, the sixth lens, and the eleventh lens are aspherical lenses. The aspherical lens is characterized in that: the curvature varies continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better radius of curvature characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. By adopting the aspherical lens, aberration occurring at the time of imaging can be eliminated as much as possible, thereby improving imaging quality.
However, those skilled in the art will appreciate that the various results and advantages described in this specification can be obtained by varying the number of lenses making up a projection lens without departing from the technical solution claimed in the present application. For example, although the embodiment has been described with an example of twelve lenses, the projection lens is not limited to the above-described number of lenses. The projection lens may also include other numbers of lenses, if desired.
Specific examples of projection lenses applicable to the above embodiments are further described below with reference to the accompanying drawings.
Example 1
A projection lens according to embodiment 1 of the present application is described below with reference to fig. 1 to 2D. Fig. 1 shows a schematic configuration of a projection lens according to embodiment 1 of the present application.
As shown in fig. 1, an image beam of a projection lens is transmitted from an image side to an object side of the projection lens, and the projection lens sequentially includes, from the object side to the image side along an optical axis: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an aperture stop, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, and three flat glasses E13, E14, E15.
The first lens element E1 has positive refractive power, wherein an object-side surface S1 thereof is convex, and image-side surfaces S2 and S3 thereof are concave. The second lens element E2 has negative refractive power, wherein an object-side surface S4 thereof is concave, and an image-side surface S5 thereof is concave. The third lens element E3 has positive refractive power, wherein an object-side surface S6 thereof is concave, and an image-side surface S7 thereof is convex. The fourth lens element E4 has positive refractive power, wherein an object-side surface S8 thereof is convex, and an image-side surface S9 thereof is concave. The fifth lens element E5 has negative refractive power, wherein an object-side surface S10 thereof is concave, and an image-side surface S11 thereof is concave. The sixth lens element E6 has positive refractive power, wherein an object-side surface S12 thereof is convex, and an image-side surface S13 thereof is convex. The seventh lens element E7 has positive refractive power, wherein an object-side surface S14 thereof is concave, and an image-side surface S15 thereof is convex. The eighth lens element E8 has negative refractive power, wherein an object-side surface S16 thereof is concave and an image-side surface S17 thereof is convex. The ninth lens element E9 has negative refractive power, wherein an object-side surface S18 thereof is convex, and an image-side surface S19 thereof is concave. The tenth lens element E10 has positive refractive power, and its object-side surface S20 is convex, and its image-side surface S21 is convex. The eleventh lens element E11 has positive refractive power, and has a convex object-side surface S22 and a convex image-side surface S23. The twelfth lens element E12 has positive refractive power, wherein an object-side surface S24 thereof is convex, and an image-side surface S25 thereof is convex. The first plate glass E13 has an object side surface S26 and an image side surface S27, and the second plate glass E14 has an object side surface S28 and an image side surface S29. The third sheet glass E15 has an object side surface S30 and an image side surface S31. The projection lens has an imaging surface S32, and the image light on the imaging surface S32 sequentially passes through the surfaces S31 to S1 and finally forms a projection screen.
Table 1 shows the basic parameter table of the projection lens of example 1, in which the unit of curvature radius, thickness is millimeter (mm).
TABLE 1
In embodiment 1, the total effective focal length f of the projection lens is-1.50 and mm, and the distance TTL between the object side surface and the imaging surface along the optical axis of the first lens is 89.42 mm.
In embodiment 1, the object side surface and the image side surface of any one of the first lens E1, the second lens E2, the sixth lens E6, and the eleventh lens E11 are aspherical surfaces, and the surface type of each aspherical lensThe following aspherical formula may be used but is not limited to:
（1）
wherein,is aspheric and has a height in the direction of the optical axishIs higher than the distance vector from the vertex of the aspheric surface;cis the paraxial curvature of an aspherical surface,c=1/R (i.e. paraxial curvaturecThe reciprocal of the radius of curvature R in table 1 above);kis a conic coefficient;Aiis an aspheric surfacei-a correction factor of th order. Table 2 below shows the K values and higher order coefficients of S1, S2, S3, S4, S5, S12, S13, S22, S23 that can be used for each of the aspherical mirrors in example 1A 4 、A 6 、A 8 、A 10 、A 12 、A 14 AndA 16 。
TABLE 2
Fig. 2A shows longitudinal spherical aberration curves of the projection lens of embodiment 1 using light rays of wavelengths 455mm, 550mm, and 630mm, which represent spherical aberration corresponding to different focal lengths. Fig. 2B shows astigmatism curves of the projection lens of embodiment 1 using light rays of wavelengths 455mm, 550mm, and 630mm, which represent meridional image plane curvature and sagittal image plane curvature, and fig. 2A and 2B reflect that the projection lens has a low optical distortion level to some extent. Fig. 2C shows distortion curves of the projection lens of embodiment 1 using light rays with wavelengths of 455mm, 550mm and 630mm, which represent distortion magnitude values corresponding to different image heights, and it can be seen from fig. 2C that the projection lens has a relatively low maximum distortion ratio and better optical performance. Fig. 2D shows the MTF curves of the imaging quality of the projection lens of example 1, and as can be seen from fig. 2D, the ordinate values corresponding to the abscissa of the MTF curves of 0.80lp/mm (line pair/millimeter) are all greater than 60%, which means that each pixel can be clearly resolved, and good image quality is obtained. As can be seen from fig. 2A to 2D, the projection lens according to embodiment 1 can achieve good imaging quality.
It should be noted that, the meridian image surfaces in fig. 2B, fig. 4B and fig. 6B are curved to form a meridian curve, and the sagittal image surfaces are curved to form a sagittal curve, wherein the meridian curve and the sagittal curve are distinguished by a circle, and the sagittal curve is a sagittal curve with a circle.
Example 2
A projection lens according to embodiment 2 of the present application is described below with reference to fig. 3 to 4D. Fig. 3 shows a schematic structure of a projection lens according to embodiment 2 of the present application.
As shown in fig. 3, the image beam of the projection lens is transmitted from the image side to the object side of the projection lens, and the projection lens sequentially includes, from the object side to the image side along the optical axis: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an aperture stop, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, and three flat glasses E13, E14, E15.
The first lens element E1 has positive refractive power, wherein an object-side surface S1 thereof is convex, and image-side surfaces S2 and S3 thereof are concave. The second lens element E2 has negative refractive power, wherein an object-side surface S4 thereof is concave, and an image-side surface S5 thereof is concave. The third lens element E3 has positive refractive power, wherein an object-side surface S6 thereof is concave, and an image-side surface S7 thereof is convex. The fourth lens element E4 has positive refractive power, wherein an object-side surface S8 thereof is convex, and an image-side surface S9 thereof is concave. The fifth lens element E5 has negative refractive power, wherein an object-side surface S10 thereof is concave, and an image-side surface S11 thereof is concave. The sixth lens element E6 has positive refractive power, wherein an object-side surface S12 thereof is convex, and an image-side surface S13 thereof is convex. The seventh lens element E7 has positive refractive power, wherein an object-side surface S14 thereof is concave, and an image-side surface S15 thereof is convex. The eighth lens element E8 has negative refractive power, wherein an object-side surface S16 thereof is concave and an image-side surface S17 thereof is convex. The ninth lens element E9 has negative refractive power, wherein an object-side surface S18 thereof is convex, and an image-side surface S19 thereof is concave. The tenth lens element E10 has positive refractive power, and its object-side surface S20 is convex, and its image-side surface S21 is convex. The eleventh lens element E11 has positive refractive power, and has a convex object-side surface S22 and a convex image-side surface S23. The twelfth lens element E12 has positive refractive power, wherein an object-side surface S24 thereof is convex, and an image-side surface S25 thereof is convex. The first plate glass E13 has an object side surface S26 and an image side surface S27, and the second plate glass E14 has an object side surface S28 and an image side surface S29. The third sheet glass E15 has an object side surface S30 and an image side surface S31. The projection lens has an imaging surface S32, and the image light on the imaging surface S32 sequentially passes through the surfaces S31 to S1 and finally forms a projection screen.
In embodiment 2, the total effective focal length f of the projection lens is-1.50 and mm, and the distance TTL between the object side surface and the imaging surface along the optical axis of the first lens is 87.54 and mm.
Table 3 shows the basic parameter table of the projection lens of example 2, in which the unit of radius of curvature, thickness is millimeter (mm). Table 4 shows the higher order coefficients that can be used for each aspherical mirror in example 2, wherein each aspherical surface profile can be defined by the formula (1) given in example 2 above.
TABLE 3 Table 3
TABLE 4 Table 4
Fig. 4A shows longitudinal spherical aberration curves of the projection lens of embodiment 2 using light rays of wavelengths 455mm, 550mm, and 630mm, which represent spherical aberration corresponding to different focal lengths. Fig. 4B shows astigmatism curves of the projection lens of embodiment 2 using light rays of wavelengths 455mm, 550mm, and 630mm, which represent meridional image plane curvature and sagittal image plane curvature, and fig. 4A and 4B reflect that the projection lens has a low optical distortion level to some extent. Fig. 4C shows distortion curves of the projection lens of embodiment 2 using light rays with wavelengths of 455mm, 550mm and 630mm, which represent distortion magnitude values corresponding to different image heights, and it can be seen from fig. 4C that the projection lens has a relatively low maximum distortion ratio and better optical performance. Fig. 4D shows the MTF curves of the imaging quality of the projection lens of example 2, and as can be seen from fig. 4D, the ordinate values corresponding to the abscissa of the MTF curves of 0.80lp/mm (line pair/millimeter) are all greater than 60%, which means that each pixel can be clearly resolved, and good image quality is obtained. As can be seen from fig. 4A to 4D, the projection lens according to embodiment 2 can achieve good imaging quality.
Example 3
A projection lens according to embodiment 3 of the present application is described below with reference to fig. 5 to 6D. Fig. 5 shows a schematic structural view of a projection lens according to embodiment 3 of the present application.
As shown in fig. 5, the image beam of the projection lens is transmitted from the image side to the object side of the projection lens, and the projection lens sequentially includes, from the object side to the image side along the optical axis: the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the stop STO, the seventh lens E7, the eighth lens E8, the ninth lens E9, the tenth lens E10, the eleventh lens E11, and the twelfth lens E12 are three flat glass sheets E13, E14, and E15.
The first lens element E1 has positive refractive power, wherein an object-side surface S1 thereof is convex, and image-side surfaces S2 and S3 thereof are concave. The second lens element E2 has negative refractive power, wherein an object-side surface S4 thereof is concave, and an image-side surface S5 thereof is concave. The third lens element E3 has positive refractive power, wherein an object-side surface S6 thereof is concave, and an image-side surface S7 thereof is convex. The fourth lens element E4 has positive refractive power, wherein an object-side surface S8 thereof is convex, and an image-side surface S9 thereof is concave. The fifth lens element E5 has negative refractive power, wherein an object-side surface S10 thereof is concave, and an image-side surface S11 thereof is concave. The sixth lens element E6 has positive refractive power, wherein an object-side surface S12 thereof is convex, and an image-side surface S13 thereof is convex. The seventh lens element E7 has positive refractive power, wherein an object-side surface S14 thereof is concave, and an image-side surface S15 thereof is convex. The eighth lens element E8 has negative refractive power, and has a concave object-side surface S16 and a concave image-side surface S17. The ninth lens element E9 has negative refractive power, wherein an object-side surface S18 thereof is convex, and an image-side surface S19 thereof is concave. The tenth lens element E10 has positive refractive power, and its object-side surface S20 is convex, and its image-side surface S21 is convex. The eleventh lens element E11 has positive refractive power, and has a convex object-side surface S22 and a convex image-side surface S23. The twelfth lens element E12 has positive refractive power, wherein an object-side surface S24 thereof is convex, and an image-side surface S25 thereof is convex. The first plate glass E13 has an object side surface S26 and an image side surface S27, and the second plate glass E14 has an object side surface S28 and an image side surface S29. The third sheet glass E15 has an object side surface S30 and an image side surface S31. The projection lens has an imaging surface S32, and the image light on the imaging surface S32 sequentially passes through the surfaces S31 to S1 and finally forms a projection screen.
In embodiment 3, the total effective focal length f of the projection lens is-1.50 and mm, and the distance TTL from the object side surface to the imaging surface of the first lens element along the optical axis is 89.51 and mm.
Table 5 shows the basic parameter table of the projection lens of example 3, in which the unit of radius of curvature, thickness is millimeter (mm). Table 6 shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 3, wherein each of the aspherical surface types can be defined by the formula (1) given in example 3 above.
TABLE 5
TABLE 6
Fig. 6A shows longitudinal spherical aberration curves of the projection lens of embodiment 3 using light rays of wavelengths 455mm, 550mm, and 630mm, which represent spherical aberration corresponding to different focal lengths. Fig. 6B shows astigmatism curves of the projection lens of example 3 using light rays of wavelengths 455mm, 550mm, and 630mm, which represent meridional image plane curvature and sagittal image plane curvature, and fig. 6A and 6B reflect that the projection lens has a low optical distortion level to some extent. Fig. 6C shows distortion curves of the projection lens of embodiment 3 using light rays with wavelengths of 455mm, 550mm and 630mm, which represent distortion magnitude values corresponding to different image heights, and it can be seen from fig. 6C that the projection lens has a relatively low maximum distortion ratio and better optical performance. Fig. 6D shows the MTF curves of the imaging quality of the projection lens of example 3, and as can be seen from fig. 6D, the ordinate values corresponding to the abscissa of the MTF curves of 0.80lp/mm (line pair/millimeter) are all greater than 60%, which means that each pixel can be clearly resolved, and good image quality is obtained. As can be seen from fig. 6A to 6D, the projection lens according to embodiment 3 can achieve good imaging quality.
The application also provides a projection device 100. Fig. 7 is a schematic structural view of a projection apparatus 100 according to an exemplary embodiment of the present application. As shown in fig. 7, the projection apparatus 100 includes an illumination system 10, a mirror 20, a spatial light modulation system 30, and a projection lens 40. The illumination system 10 is for providing an illumination beam. The spatial light modulation system 20 is disposed on a transmission path of the illumination beam, and is used for modulating the illumination beam into an image beam. The projection lens 40 is disposed on the transmission path of the image beam, and is used for receiving the image beam from the spatial light modulation system 30 and projecting the projection beam. The projection beam forms an image on the projection surface 101 after being projected from the projection device 100, and the image beam is transmitted through the rear refractive mirror group and the reflective mirror group in sequence to form a projection beam, and forms a projection screen on the projection surface.
The illumination system 10 includes a plurality of light emitting elements and a plurality of light splitting and combining elements, for example, to provide light with different wavelengths as sources of image light. The plurality of light emitting elements are, for example, metal halogen bulbs (Lamp), high-pressure mercury bulbs, or solid-state light emitting sources (solid-state stateillumination source), such as light emitting diodes (light emitting diode), laser diodes (laserdiode), and the like. However, the present application is not limited to the type or form of the illumination system 10 in the projection apparatus 100, and the detailed structure and implementation thereof can be taught, suggested and illustrated by the common general knowledge in the art, so that the detailed description thereof is omitted.
In the present embodiment, the spatial light modulation system 30 is a reflective light modulator such as a liquid crystal silicon (lc) panel (Liquid Crystal On Silicon panel), a Digital Micro-mirror Device (DMD), or the like. In some embodiments, the spatial light modulation system may also be a transmissive liquid crystal panel (Transparent Liquid Crystal Panel), an Electro-Optic Modulator (Electro-Optical Modulator), a Magneto-Optic Modulator (Magneto-Optic Modulator), an Acousto-Optic Modulator (AOM), or the like. The type and kind of the spatial light modulation system 30 is not limited in the present application. The method for modulating the illumination beam into the image beam by the spatial light modulation system 30 can be sufficiently taught, suggested and implemented by common general knowledge in the art, and thus will not be described in detail. In the present embodiment, the number of spatial light modulation systems 30 is one, for example, a projection apparatus using a single Digital Micromirror Device (DMD), but may be plural in other embodiments, and the present application is not limited thereto.
The above description is only illustrative of the preferred embodiments of the present application and of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the application is not limited to the specific combination of the above technical features, but also encompasses other technical features which may be combined with any combination of the above technical features or their equivalents without departing from the spirit of the application. Such as the above-mentioned features and the technical features disclosed in the present application (but not limited to) having similar functions are replaced with each other.

Claims (10)

1. The utility model provides a projection lens which characterized in that, along image beam transmission direction by in proper order: the refraction mirror group and the reflecting mirror group;
the reflecting mirror group consists of a first lens and a reflecting surface, and the reflecting surface is arranged on one side of the first lens far away from the refracting mirror group;
the refraction mirror group is formed by sequentially following the transmission direction of the image light beam: a twelfth lens, an eleventh lens, a tenth lens, a ninth lens, an eighth lens, a seventh lens, an aperture, a sixth lens, a fifth lens, a fourth lens, a third lens, and a second lens; wherein,
the first lens has positive optical power;
the second lens has negative optical power;
the third lens and the fourth lens have positive focal power;
the fifth lens has negative focal power;
the sixth lens and the seventh lens have positive focal power;
the eighth lens and the ninth lens have negative focal power;
the tenth lens, the eleventh lens, and the twelfth lens have positive optical power;
the distance T23 between the edge of the second lens and the edge of the third lens along the optical axis satisfies: t23 > 0.10mm;
effective focal length f of the refractive lens group t The method meets the following conditions: -f is less than or equal to 8.09mm t The effective focal length f of the reflecting mirror group is less than or equal to 7.01mm r The method meets the following conditions: -f is less than or equal to 8.57mm r ≤-7.95mm。
2. The projection lens of claim 1, wherein a separation distance T23 along the optical axis between an edge of the second lens and an edge of the third lens satisfies: t23 is more than or equal to 0.60mm and less than or equal to 3.00mm.
3. The projection lens of claim 1, wherein a separation distance T45 along the optical axis between an edge of the fourth lens and an edge of the fifth lens satisfies: t45 is more than or equal to 0 and less than or equal to 0.10mm.
4. A projection lens according to claim 3, wherein the distance T45 between the edge of the fourth lens and the edge of the fifth lens along the optical axis is such that: t45=0.
5. A projection lens according to claim 3, wherein a distance L45 between a center of the fourth lens and a center of the fifth lens along the optical axis satisfies: l45 is more than or equal to T45, and L45 is more than or equal to 1.09mm and less than or equal to 3.87mm.
6. A projection lens according to claim 3, wherein the radius of curvature R42 of the image side surface of the fourth lens satisfies: 46.75mm < R42 > 106.53mm, and the curvature radius R51 of the object side surface of the fifth lens satisfies the following conditions: 21.71mm or less R51 or less-11.64 and mm.
7. The projection lens of claim 1, wherein the radius of curvature of the object-side surface of the first lens as R11 and the radius of curvature of the image-side surface of the first lens as R12 satisfy: R11/R12 is more than or equal to 0.30 and less than or equal to 0.64.
8. The projection lens of claim 1 wherein the thickness of the first lens is greater than the thickness of the second lens in the direction of the optical axis.
9. The projection lens of claim 1 wherein the first lens, the second lens, the sixth lens and the twelfth lens are all aspheric lenses.
10. Projection device, characterized in that it comprises an illumination system, a spatial light modulation system and a projection lens according to any of claims 1-9, wherein,
the illumination system is used for providing an illumination beam;
the spatial light modulation system is configured on a transmission path of the illumination light beam and is used for modulating the illumination light beam into an image light beam; and
the projection lens is configured on the transmission path of the image light beam and is used for projecting the image light beam out of the projection device to form a projection picture, wherein the image light beam sequentially passes through the refraction mirror group and the reflection mirror group to form the projection picture.
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Publication number Priority date Publication date Assignee Title
CN106842590A (en) * 2017-03-28 2017-06-13 中山联合光电科技股份有限公司 A kind of ultrashort out-of-focus projection's optical system
CN107144944A (en) * 2017-07-19 2017-09-08 中山联合光电科技股份有限公司 A kind of ultrashort out-of-focus projection's optical system
CN109884780A (en) * 2019-04-16 2019-06-14 中山联合光电科技股份有限公司 A kind of inexpensive, high-resolution ultrashort out-of-focus projection's optical system
CN110824674A (en) * 2019-12-24 2020-02-21 嘉兴中润光学科技有限公司 Optical lens for projection

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106842590A (en) * 2017-03-28 2017-06-13 中山联合光电科技股份有限公司 A kind of ultrashort out-of-focus projection's optical system
CN107144944A (en) * 2017-07-19 2017-09-08 中山联合光电科技股份有限公司 A kind of ultrashort out-of-focus projection's optical system
CN109884780A (en) * 2019-04-16 2019-06-14 中山联合光电科技股份有限公司 A kind of inexpensive, high-resolution ultrashort out-of-focus projection's optical system
CN110824674A (en) * 2019-12-24 2020-02-21 嘉兴中润光学科技有限公司 Optical lens for projection

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