CN114114644A - Projection lens and projection system - Google Patents

Projection lens and projection system Download PDF

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Publication number
CN114114644A
CN114114644A CN202111667597.1A CN202111667597A CN114114644A CN 114114644 A CN114114644 A CN 114114644A CN 202111667597 A CN202111667597 A CN 202111667597A CN 114114644 A CN114114644 A CN 114114644A
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China
Prior art keywords
lens
projection
group
light
lens group
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CN202111667597.1A
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Chinese (zh)
Inventor
陈陆
阴亮
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Qingdao Hisense Laser Display Co Ltd
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Qingdao Hisense Laser Display Co Ltd
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Priority to CN202111667597.1A priority Critical patent/CN114114644A/en
Publication of CN114114644A publication Critical patent/CN114114644A/en
Priority to PCT/CN2022/136659 priority patent/WO2023124812A1/en
Pending legal-status Critical Current

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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
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/0065—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element having a beam-folding prism or mirror
    • 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
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • 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
    • G03B21/142—Adjusting of projection optics

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

Abstract

The invention discloses a projection lens and a projection system, wherein the projection system comprises: projection light source, light valve modulation part and projection lens. The light valve modulation component adopts a 0.66' 4K high-resolution DMD, which can realize large-size high-resolution display; the projection lens includes: a refractive system and a reflective system, the refractive system comprising: the rear lens group comprises a double-cemented lens group, and the front lens group comprises a double-cemented lens group; the reflection system comprises a mirror for reflecting the imaging light of the refraction system. The problem of large red, green and blue three-color deviation is solved by adopting two double-cemented lens groups, and the quality of a projection picture is improved. The double-cemented lens group in the rear lens group is mainly used for improving the spherical aberration of the lens in different spectrums and correcting the astigmatism of the lens; the double cemented lens set in the front lens group is mainly used for correcting the residual transverse chromatic aberration of the system.

Description

Projection lens and projection system
Technical Field
The invention relates to the technical field of projection display, in particular to a projection lens and a projection system.
Background
In a Digital Light Processing (DLP) based projection system, Light emitted from a Light source is modulated and then irradiated onto a Digital Micromirror Device (DMD), reflected by a micromirror unit on the DMD and then irradiated onto a projection lens, and projected onto a projection screen through the projection lens to form an image.
At present, DLP projection systems generally adopt telecentric optical path architectures and have better imaging quality, but a beam splitter prism is arranged by a larger rear working distance between a DMD and a projection lens, so that the overall volume of the projection system is larger, the projection system occupies a larger use space, and meanwhile, the DLP projection systems have higher cost.
Disclosure of Invention
In some embodiments of the present invention, a projection lens includes: a refractive system and a reflective system, the refractive system comprising: the rear lens group comprises a double-cemented lens group, and the front lens group comprises a double-cemented lens group; the reflection system comprises a mirror for reflecting the imaging light of the refraction system. The problem of large red, green and blue three-color deviation is solved by adopting two double-cemented lens groups, and the quality of a projection picture is improved. The double-cemented lens group in the rear lens group is mainly used for improving the spherical aberration of the lens in different spectrums and correcting the astigmatism of the lens; the double cemented lens set in the front lens group is mainly used for correcting the residual transverse chromatic aberration of the system. Two double-cemented lens sets are adopted for matching use, so that the machining precision can be reduced on the premise of ensuring effective correction of chromatic aberration, and the manufacturability design is provided.
In some embodiments of the present invention, the projection lens adopts a secondary imaging structure, the image light passes through the refraction system, and then is subjected to a first imaging between the reflection system and the refraction system, and the first imaging is reflected by the reflection system and then is subjected to a secondary imaging at a set position.
In some embodiments of the present invention, the reflection system includes a mirror located on the light exit side of the refraction system for folding the light path for imaging, thereby reducing the length and size of the projection lens. In an embodiment of the invention, a mirror participates in the imaging for compressing the light rays to a large extent.
In some embodiments of the present invention, the reflective system is disposed coaxially with the rear lens group, the middle lens group and the front lens group. The relative positions of the middle lens group, the front lens group and the rear lens group are adjusted along the optical axis, so that focusing imaging under different projection sizes can be realized. The front group lens group is movable relative to the reflecting system, and displacement of the front group lens group relative to the reflecting system is adjusted according to projection conditions of different sizes, so that good distortion performance under different sizes can be realized.
In some embodiments of the present invention, the rear lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially disposed along a direction gradually approaching the reflection system. Wherein, the first lens is an aspheric lens; the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all spherical lenses. The diopter of the first lens is positive, the diopter of the second lens is negative, the diopter of the third lens is positive, the diopter of the fourth lens is negative, the diopter of the fifth lens is positive, and the diopter of the sixth lens is negative.
In some embodiments of the present invention, the first lens may be a convex-concave aspheric lens, and a glass aspheric lens is used to improve spherical aberration and astigmatism, thereby improving the resolution of the projection lens. Meanwhile, the glass aspheric lens has a lower thermal expansion coefficient, a small temperature coefficient of the refractive index, good uniformity of the refractive index and stable optical performance, so that the first lens close to the light source adopts the glass aspheric lens to ensure that the projection system has good imaging quality.
In some embodiments of the present invention, the third lens and the fourth lens are cemented together to form a double cemented lens set. The abbe number of the third lens is larger than that of the fourth lens; the refractive index of the third lens is smaller than that of the fourth lens.
In some embodiments of the present invention, the middle lens group includes a seventh lens and an eighth lens sequentially disposed along a direction gradually approaching the reflection system. The seventh lens is a spherical lens, and the eighth lens is an aspheric lens; the diopter of the seventh lens is positive, and the diopter of the eighth lens is negative.
In some embodiments of the present invention, the eighth lens is an aspheric concave-convex lens, and a glass aspheric lens is used to improve astigmatism and coma.
In some embodiments of the present invention, the front group lens group includes a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens sequentially arranged in a direction gradually approaching the reflection system. The ninth lens, the tenth lens, the eleventh lens and the twelfth lens are spherical lenses; the thirteenth lens is an aspherical lens. Diopter of the ninth lens is positive, diopter of the tenth lens is negative, diopter of the eleventh lens is positive, diopter of the twelfth lens is negative, and diopter of the thirteenth lens is positive. The reflection system can compress light rays in a large proportion, and the thirteenth lens close to the reflection system is arranged to be a concave-convex aspheric lens, so that astigmatism can be effectively improved, and distortion can be effectively corrected.
In some embodiments of the present invention, the thirteenth lens element is a plastic aspheric lens element. The aperture of the aspheric lens close to the reflecting system is larger, so that the thirteenth lens is made of plastic materials which are easy to mold, and the cost and the manufacturing difficulty can be reduced.
In some embodiments of the present invention, the eleventh lens and the twelfth lens are cemented together to form a double cemented lens group. The abbe number of the eleventh lens is smaller than that of the twelfth lens, and the refractive index of the eleventh lens is larger than that of the twelfth lens.
In some embodiments of the present invention, the reflection system may employ a concave mirror for secondary imaging of the imaging light and reflecting the imaging light to a set position. The concave reflector can adopt an aspheric reflector or a free-form surface reflector. The concave reflector participates in imaging, and light compression is effectively carried out, so that large-size image display is realized. Distortion is inevitably generated when light is compressed in a large proportion, so astigmatism and distortion can be effectively corrected by using the aspherical mirror and the free-form surface mirror.
In some embodiments of the present invention, the equivalent focal length of the projection lens, the equivalent focal length of the rear group lens, the equivalent focal length of the middle group lens, the equivalent focal length of the front group lens, and the equivalent focal length of the reflection system satisfy the following relationships:
1<|FB/F|<12；
40<|FM/F|<600；
320<|FF/F|<360；
5<|FC/F|<10；
wherein, F represents the equivalent focal length of the projection lens, FB represents the equivalent focal length of the rear lens group, represents the equivalent focal length of the middle lens group, FF represents the equivalent focal length of the front lens group, and FC represents the equivalent focal length of the reflection system.
In some embodiments of the invention, the projection ratio of the projection lens can be 0.2-0.25, the use requirement of the ultra-short-focus projection lens is met, the distance between the projector and the projection screen is greatly shortened, and large-size image display can be realized while the projection distance is shortened.
In some embodiments of the invention, the refractive system and the reflective system satisfy the following relationship:
1.5<L1/L2<2；
the rear working distance of the projection lens meets the following relation:
0.2<BFL/L2<0.4；
where L1 denotes the total length of the refractive system, L2 denotes the distance between the refractive system and the reflective system, and BFL denotes the rear working distance of the projection lens.
The rear working distance of the projection lens adopting the non-telecentric structure is smaller than that of the projection lens adopting the telecentric structure, so that the volume of the projection system can be effectively reduced.
In some embodiments of the present invention, a projection system includes a projection light source, a light valve modulation component, and any one of the projection lenses described above. The projection light source is used for emitting light with different colors according to time sequence; the light valve modulation component is positioned on the light emitting side of the projection light source and is used for modulating and reflecting incident light; the projection lens is positioned on the reflection light path of the light valve modulation component and is used for imaging the emergent light of the light valve modulation component.
In some embodiments of the present invention, the light valve modulating component uses a 0.66 ″ 4K high resolution digital micro-mirror, which can realize large size high resolution projection display.
In some embodiments of the present invention, the projection system further includes a projection screen, the projection screen is disposed on a side of the refraction system away from the reflection system, a distance between the projection lens and the projection screen is relatively small, and there is no situation that an object enters between the projection lens and the projection screen, so that a problem that a picture is blocked is avoided, and a use space is saved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a projection lens according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of TV distortion provided by an embodiment of the present invention;
FIG. 3a is a light fan diagram of an image plane (screen side) according to an embodiment of the present invention;
FIG. 3b is a second light fan diagram of an image plane (screen end) according to an embodiment of the present invention;
FIG. 3c is a third light fan diagram of an image plane (screen end) according to the present invention;
FIG. 4 is a schematic structural diagram of a projection system according to an embodiment of the present invention;
fig. 5 is a second schematic structural diagram of a projection system according to an embodiment of the invention.
The system comprises a 100-refraction system, a 200-reflection system, an 11-rear lens group, a 12-middle lens group, a 13-front lens group, a 111-first lens, a 112-second lens, a 113-third lens, a 114-fourth lens, a 115-fifth lens, a 116-sixth lens, a 121-seventh lens, a 122-eighth lens, a 131-ninth lens, a 132-tenth lens, a 133-eleventh lens, a 134-twelfth lens, a 135-thirteenth lens, an x 1-double-cemented lens group, an x 2-double-cemented lens group, a 300-light valve modulation component, a 400-projection light source, a 600-projection lens and a 500-projection screen.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is further described with reference to the accompanying drawings and examples. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their repetitive description will be omitted. The words expressing the position and direction described in the present invention are illustrated in the accompanying drawings, but may be changed as required and still be within the scope of the present invention. The drawings of the present invention are for illustrative purposes only and do not represent true scale.
With the continuous development of projection technology, projection display devices have been developed from the fields of traditional business education and the like to display products that replace televisions. The projection display is to control the light source by the plane image information, enlarge and display the image on the projection screen by using the optical system and the projection space.
The existing projection system may adopt a Digital Light Processing (DLP) architecture, and a Digital Micromirror Device (DMD) is used as a core Device, and Light emitted from a projection Light source is incident on the DMD to generate an image, and then the emergent Light of the image generated by the DMD is incident on a projection lens, and is imaged by the projection lens, and finally received by a projection screen.
The light emitted from the projection lens is usually projected onto a screen or a wall, and then reflected by the projection screen or the wall to enter human eyes. At present, a certain distance is needed between a projection lens and a projection screen of a household projector to enable a projection picture to be clear. However, if an object moves between the projection screen and the projection lens, the moving object will block the light emitted from the projection lens, so that the picture on the projection screen is lost, and the display effect is affected.
Therefore, the existing household projection equipment adopts an ultra-short focal lens. The ultra-short focal lens has short projection distance, large requirement on a view field, high imaging requirement, and high design difficulty due to the consideration of cost and miniaturization. The conventional projection lens usually adopts a telecentric light path structure and has good imaging quality, but the telecentric light path structure requires that the main light rays for imaging are parallel light, so that the design of the projection lens is complex, the rear end of an optical system is large, and the volume of the projection lens is increased. And a larger rear working distance is needed between the light valve modulation component and the projection lens to arrange the beam splitter prism, so that light is split and transposed, the whole volume of the projection system is larger, and a larger use space is occupied. Meanwhile, the cost of the beam splitting prism is high, which is not beneficial to controlling the cost of the projection system.
In view of this, embodiments of the present invention provide a projection lens and a projection system, which can implement large-size high-resolution projection imaging based on a 0.66 ″ 4K high-resolution DMD. The projection lens adopts a non-telecentric structure, which is beneficial to reducing the volume of the projection lens. Meanwhile, a projection lens with a non-telecentric structure is adopted, a beam splitter prism is not needed, and the volume and the cost of the projection equipment can be reduced. Through reasonable optical design, aberration can be corrected, and imaging quality is improved.
Fig. 1 is a schematic structural diagram of a projection lens according to an embodiment of the present invention.
As shown in fig. 1, the projection lens provided by the present invention includes: a refractive system 100 and a reflective system 200.
The refractive system 100 is generally located on the light-emitting side of the light valve modulating component for imaging the image light emitted from the light valve modulating component.
The reflection system 200 is located on the light-emitting side of the refraction system 100, and is used for re-imaging the imaging light of the refraction system and reflecting the imaging light to a set position.
The projection lens provided by the embodiment of the invention adopts a secondary imaging framework, after a light valve reflected light beam passes through the refraction system 100, primary imaging is carried out between the reflection system 200 and the refraction system 100, and after the primary imaging is reflected by the reflection system 200, secondary imaging is carried out at a set position. In general, a projection screen may be disposed at a set position for receiving the imaging light of the projection lens for image display.
When the projection screen is applied specifically, the projection screen can be arranged on one side of the refraction system, which is away from the reflection system, the distance between the projection lens and the projection screen is relatively small, and the condition that an object enters between the projection lens and the projection screen does not exist, so that the problem that a picture is shielded is avoided, and the use space is saved.
As shown in fig. 1, the refractive system 100 includes a rear group lens 11, a middle group lens 12, and a front group lens 13. The front lens group 13 is located on a side close to the reflection system 200, the middle lens group 12 is located on a side of the front lens group 13 away from the reflection system 200, and the rear lens group 11 is located on a side of the middle lens group 13 away from the front lens group 13.
The reflection system 200 includes a mirror on the light exit side of the refraction system 100 for folding the light path for imaging, thereby reducing the length and size of the projection lens. In an embodiment of the invention, a mirror participates in the imaging for compressing the light rays to a large extent.
The reflection system 200 is disposed coaxially with the rear lens group 11, the middle lens group 12, and the front lens group 13. By adjusting the relative positions of the middle lens group 12, the front lens group 13 and the rear lens group 11 along the optical axis, focusing imaging under different projection sizes can be realized. The front group lens group 13 is movable relative to the reflection system 200, and the displacement of the front group lens group 13 relative to the reflection system 200 is adjusted according to projection conditions of different sizes, so that good distortion performance can be realized under different sizes.
As shown in fig. 1, the rear lens group 11 includes a cemented doublet x1 for improving the spherical aberration of different spectra of the projection lens and correcting the astigmatism of the lens; the front lens group 13 includes a double cemented lens group x2, which is mainly used to correct the residual lateral chromatic aberration of the system. Through the cooperation of two cemented lens group x1 and x2 use, can correct the colour difference effectively, solve the big problem of red green blue tristimulus deviation, promote projection picture quality, can reduce the machining precision simultaneously, provide the manufacturability design.
Specifically, as shown in fig. 1, the rear lens group 11 includes a first lens 111, a second lens 112, a third lens 113, a fourth lens 114, a fifth lens 115, and a sixth lens 116, which are sequentially disposed in a direction gradually approaching the reflection system.
The first lens 111 is an aspheric lens; the second lens 112, the third lens 113, the fourth lens 114, the fifth lens 115, and the sixth lens 116 are all spherical lenses.
Diopter of the first lens 111 is positive, diopter of the second lens 112 is negative, diopter of the third lens 113 is positive, diopter of the fourth lens 114 is negative, diopter of the fifth lens 115 is positive, and diopter of the sixth lens 116 is negative.
The embodiment of the invention arranges the aspherical mirror in the rear lens group 11 of the projection lens, which can improve spherical aberration and astigmatism. In particular, the lens on the side close to the light incident side of the projection lens may be an aspheric lens, for example, the first lens 111 may be an aspheric lens, thereby improving spherical aberration and astigmatism and improving the resolution of the projection lens.
In the embodiment of the present invention, the first lens 111 is a glass aspherical lens. The first lens 111 is located on the light incident side of the projection lens and generally arranged close to the light source, the temperature is high, the glass aspheric lens has a low thermal expansion coefficient, the temperature coefficient of the refractive index is low, the uniformity of the refractive index is good, and the optical performance is stable, so that the first lens 111 adopts the glass aspheric lens to ensure that the projection system has good imaging quality.
In a specific implementation, the first lens 111 may be an axisymmetric aspheric lens, and specifically, a convex-concave aspheric lens is used.
The third lens 113 and the fourth lens 114 are cemented with each other to constitute a double cemented lens group x 1. The abbe number of the fourth lens 114 is smaller than that of the third lens 113, and the refractive index of the fourth lens 114 is larger than that of the third lens 113. The value range of the abbe number vd3 of the third lens 113 is as follows: 50< vd3<70, refractive index nd3>1.6 of the third lens 113. When the optical design is performed, the third lens and the fourth lens can be processed by selecting appropriate materials according to the value range.
As shown in fig. 1, the middle lens group 12 includes a seventh lens 121 and an eighth lens 122 disposed in order in a direction gradually approaching the reflection system 200; the seventh lens 121 is a spherical lens, and the eighth lens 122 is an aspherical lens. The diopter of the seventh lens 121 is positive, and the diopter of the eighth lens 122 is negative.
The eighth lens 122 is provided as an aspherical mirror, and may be used to improve astigmatism and coma. In a specific implementation, the eighth lens 122 is designed as an axisymmetric aspheric lens, specifically, a concave-convex aspheric lens, and is made of a glass material.
As shown in fig. 1, the front group lens 13 includes a ninth lens 131, a tenth lens 132, an eleventh lens 133, a twelfth lens 134, and a thirteenth lens 135 arranged in this order in a direction gradually approaching the reflection system 200. The ninth lens 131, the tenth lens 132, the eleventh lens 133 and the twelfth lens 134 are spherical lenses; the thirteenth lens 135 is an aspherical lens. Diopter of the ninth lens 131 is positive, diopter of the tenth lens 132 is negative, diopter of the eleventh lens 133 is positive, diopter of the twelfth lens 134 is negative, and diopter of the thirteenth lens 135 is positive.
In the embodiment of the present invention, an aspherical mirror is disposed in the front lens group near the side of the reflection system 200 to improve astigmatism. In an implementation, the reflection system 200 compresses the light beam in a large proportion, and the thirteenth lens 135 is an aspheric lens, which can effectively improve astigmatism and distortion. In practical applications, the thirteenth lens 135 may be a meniscus lens.
In the embodiment of the present invention, the thirteenth lens 135 is a plastic aspheric lens. The use of a glass aspheric lens is not conducive to design and processing due to the larger caliber of the aspheric lens near the reflective system 200. Meanwhile, the thirteenth lens 135 is far from the light source and is less affected by heat. Therefore, the thirteenth lens element 135 is made of an easily molded plastic aspheric lens, which can reduce the cost and the manufacturing difficulty.
In a specific implementation, the thirteenth lens 135 is an axisymmetric aspheric lens.
The eleventh lens 133 and the twelfth lens 134 are cemented with each other to constitute a double cemented lens group x 2. The abbe number of the eleventh lens 133 is smaller than that of the twelfth lens 134, and the refractive index of the eleventh lens 133 is larger than that of the twelfth lens 134. The value range of abbe number vd11 of the eleventh lens 133 is: 15< vd11<300, refractive index nd11>1.85 of the eleventh lens 133. When the optical design is performed, the third lens and the fourth lens can be processed by selecting appropriate materials according to the value range.
The reflection system 200 may employ a concave mirror for secondary imaging of the imaging light and reflecting toward a set position. Specifically, the concave mirror may employ an aspherical mirror or a free-form surface mirror. In the embodiment of the invention, the concave reflector participates in imaging, and light compression is effectively carried out so as to realize large-size image display. Distortion is inevitably generated when light is compressed in a large proportion, so astigmatism and distortion can be effectively corrected by using the aspherical mirror and the free-form surface mirror.
In the embodiment of the present invention, the equivalent focal length of the projection lens, the equivalent focal length of the rear group lens, the equivalent focal length of the middle group lens, the equivalent focal length of the front group lens, and the equivalent focal length of the reflection system satisfy the following relations:
1<|FB/F|<12；
40<|FM/F|<600；
320<|FF/F|<360；
5<|FC/F|<10；
where F denotes an equivalent focal length of the projection lens 100, FB denotes an equivalent focal length of the rear group lens 11, FM denotes an equivalent focal length of the middle group lens 12, FF denotes an equivalent focal length of the front group lens 13, and FC denotes an equivalent focal length of the reflection system 200.
The refractive system 100 and the reflective system 200 in the projection lens as a whole generate positive diopter for converging light. The projection lens adopts a secondary imaging structure, incident light passes through the refraction system 100 and then is imaged for the first time between the reflection system 200 and the refraction system 100, and the imaged for the first time is reflected by the reflection system 200 to form a secondary undistorted image on a projection screen. The projection lens in the embodiment of the invention corrects the large field aberration through the aspheric lens, the aspheric reflector or the free-form surface reflector, so that the resolving power of the lens is improved, and the imaging quality with high resolution is realized.
The projection ratio of the projection lens adopting the non-telecentric architecture can be 0.2-0.25, the use requirement of the ultra-short-focus projection lens is met, the distance between a projector and a projection screen is greatly shortened, and large-size image display can be realized while the projection distance is shortened.
The refractive system 100 and the reflective system 200 satisfy the following relationship:
1.5<L1/L2<2；
the rear working distance of the projection lens meets the following relation:
0.2<BFL/L2<0.4；
where L1 denotes the total length of the refractive system, L2 denotes the distance between the refractive system and the reflective system, and BFL denotes the rear working distance of the projection lens.
The number of lenses is controlled by adopting the design of proper surface type and diopter for each lens in the front lens group 13, the middle lens group 12 and the rear lens group 11, so that the miniaturization is realized, and the full-color laser projection display is suitable. The two double-cemented lens groups and the 3 aspheric lenses are only used, so that the complexity and the volume of the lens are greatly reduced, and the chromatic aberration of the projection lens is effectively reduced by matching the two double-cemented lens groups. The optimization is carried out in the aspects of the volume, the design complexity, the cost and the processing of the projection lens.
The embodiment of the invention also performs optical simulation on the projection lens, wherein the F number of the projection lens is 2.35, the Effective Focal Length (FFL for short) is 3.206mm, the offset (the ratio of the distance between the center of emergent light of the light valve modulation component and the optical axis to the half height of the emergent light beam of the light valve modulation component) is 140% -150%, the resolving power can reach 93lp/mm, the size of a projected picture can be 90-120 inches, and the projection ratio (projection distance/picture Length) is 0.23-0.25.
Fig. 2 is a schematic diagram of TV distortion provided by an embodiment of the present invention, in which the horizontal axis represents the x direction and the vertical axis represents the y direction.
TV distortion performance canTo reflect the distortion degree of the projection image of the projection lens, as shown in fig. 2, the intersection points of the grids represent ideal projection picture pixel points, and each independent intersection point represents an actual projection picture pixel point. When the size of the picture is 100 inches (2214 x 1245 mm)2) In the process, the maximum TV distortion value of the projection image of the projection lens provided by the embodiment of the invention is-0.4125%, so that the practical use requirement can be met.
Fig. 3a is a first light fan diagram of an imaging plane (screen end) according to an embodiment of the present invention, fig. 3b is a second light fan diagram of the imaging plane (screen end) according to the embodiment of the present invention, and fig. 3c is a third light fan diagram of the imaging plane (screen end) according to the embodiment of the present invention. Wherein, fig. 3a, fig. 3b and fig. 3c show the aberration values between the light with the wavelength of 450nm, 525nm, 620nm and the light with the dominant wavelength on the horizontal axis and the vertical axis respectively under the normalized conditions of the minimum field of view, the central field of view and the maximum field of view.
As shown in fig. 3a, 3b and 3c, the two graphs in each field of view are the horizontal axis and the vertical axis of the projection lens in the meridional direction and the sagittal direction, respectively, which are symmetric about the optical axis; horizontal axis p in each graphx、pyThe pupil height under the field of view, vertical axis ex、eyThe x-component and the y-component of the transverse optical aberration between the respective wavelength ray and the principal ray. Wherein the maximum scale in FIGS. 3a, 3b and 3c is. + -. 1000. mu.m.
As can be seen from fig. 3a, 3b, and 3c, the coincidence degree of the curves with different wavelengths in each field of view is high, and the maximum value of the longitudinal axis is also within an acceptable range.
Fig. 4 is a schematic structural diagram of a projection system according to an embodiment of the present invention.
As shown in fig. 4, the projection system includes a projection light source 400, a light valve modulation member 300, and any one of the projection lenses 600 described above.
In the embodiment of the present invention, the projection light source 400 may adopt a laser light source, and the laser light source may adopt a monochromatic laser, a laser capable of emitting laser light of multiple colors, or multiple lasers emitting laser light of different colors. When the laser light source adopts a monochromatic laser, the laser display device also needs to be provided with a color wheel, the color wheel is used for carrying out color conversion, and the monochromatic laser can be matched with the color wheel to emit primary color light with different colors according to time sequence. When the laser light source adopts a laser capable of emitting lasers with various colors, the laser light source needs to be controlled to emit lasers with different colors as primary color light according to a time sequence.
The light valve modulation component 300 is located on the light emitting side of the projection light source 400, and is used for modulating and reflecting incident light. In specific implementation, the light valve modulating component 300 may employ a Digital micro mirror Device (DMD), the DMD is a reflective light valve Device, the surface of the DMD includes thousands of micro mirrors, and each micro mirror is used as a pixel for reflecting red light, green light, and blue light in a time-sharing manner, so that the three primary lights are fused into a color pixel at the same position. The DMD adopted in the embodiment of the invention is a 4K high-resolution DMD of 0.66' and can realize large-size high-resolution display.
The projection lens 600 is located on the reflection light path of the light valve modulation unit 300 and is used to image the outgoing light of the light valve modulation unit 300.
As shown in fig. 4, the projection system provided by the present invention adopts a non-telecentric optical path structure, and the reflected optical path modulated by the light valve modulation component 300 and reflected by the light valve modulation component does not need to be parallel to the optical axis of the projection lens 600 and then enters the projection lens, so that a beam splitter prism does not need to be additionally arranged, the structure of the projection system can be simplified, the volume of the projection system can be reduced, the design and manufacturing difficulty can be reduced, and the cost can be reduced. Meanwhile, the projection system adopts the ultra-short-focus projection lens 600 provided by the invention, and each optical lens in the ultra-short-focus projection lens 600 adopts a proper surface type and diopter design, so that the number of the lenses is controlled, the miniaturization is realized, and the projection system is suitable for projection display of full-color laser. The lens has the advantages that only two double-cemented lens groups and 3 aspheric lenses are used, the complexity and the volume of the lens are greatly reduced, the problem of large chromatic aberration deviation of a monochromatic lens is solved by matching the two double-cemented lens groups, and the lens is greatly improved in volume, complexity, cost and processing.
Fig. 5 is a second schematic structural diagram of a projection system according to an embodiment of the invention.
As shown in fig. 5, the projection system provided in the embodiment of the present invention may further include a projection screen 500, where the projection screen 500 may be a curtain assembled with the projection system, or may be a wall surface, which is not limited herein. As can be seen from fig. 5, the final image after being imaged by the projection lens 600 is projected onto the projection screen 500, and the distance between the rear surface of the projection system and the projection screen 500 is much smaller than the size of the projection screen, thereby realizing ultra-short-focus projection display.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (11)

1. A projection lens, comprising:
the refraction system is used for imaging the incident image light;
the reflection system is positioned on the light-emitting side of the refraction system and used for reflecting the imaging light of the refraction system to a set position;
the refraction system includes:
the front lens group is positioned at one side close to the reflecting system; the front lens group comprises a double cemented lens group;
the middle lens group is positioned on one side of the front lens group, which is far away from the reflecting system;
the rear lens group is positioned on one side of the middle lens group, which is far away from the front lens group; the rear lens group includes a double cemented lens group.
2. The projection lens as claimed in claim 1, wherein the rear lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence in a direction gradually approaching the reflection system;
wherein the first lens is an aspheric lens; the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all spherical lenses.
3. The projection lens of claim 2, wherein the diopter of the first lens is positive, the diopter of the second lens is negative, the diopter of the third lens is positive, the diopter of the fourth lens is negative, the diopter of the fifth lens is positive, and the diopter of the sixth lens is negative;
the third lens and the fourth lens are mutually glued; the refractive index of the fourth lens is larger than that of the third lens; the abbe number of the fourth lens is smaller than that of the third lens.
4. The projection lens as claimed in claim 1, wherein the middle group lens includes a seventh lens and an eighth lens arranged in order in a direction gradually approaching the reflection system;
the seventh lens is a spherical lens, and the eighth lens is an aspherical lens.
5. The projection lens of claim 4 wherein the refractive power of the seventh lens is positive and the refractive power of the eighth lens is negative.
6. The projection lens of claim 1 wherein the front lens group comprises a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens arranged in sequence along a direction gradually approaching the reflection system;
the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are all spherical lenses, and the thirteenth lens is an aspheric lens.
7. The projection lens of claim 6, wherein the refractive power of the ninth lens is positive, the refractive power of the tenth lens is negative, the refractive power of the eleventh lens is positive, the refractive power of the twelfth lens is negative, and the refractive power of the thirteenth lens is positive;
the eleventh lens and the twelfth lens are cemented to each other; the refractive index of the twelfth lens is smaller than that of the eleventh lens; the abbe number of the twelfth lens is larger than that of the eleventh lens.
8. The projection lens of any of claims 1-7 wherein the reflective system is a concave mirror; the concave reflector is an aspheric reflector or a free-form surface reflector.
9. The projection lens of claim 8 wherein the equivalent focal length of the projection lens, the equivalent focal length of the rear group lens, the equivalent focal length of the middle group lens, the equivalent focal length of the front group lens, and the equivalent focal length of the reflection system satisfy the following relationships:
1<|FB/F|<12；
40<|FM/F|<600；
320<|FF/F|<360；
5<|FC/F|<10；
wherein F represents an equivalent focal length of the projection lens, FB represents an equivalent focal length of the rear lens group, FM represents an equivalent focal length of the middle lens group, FF represents an equivalent focal length of the front lens group, and FC represents an equivalent focal length of the reflection system.
10. The projection lens of any of claims 1-7 wherein the projection lens has a throw ratio of 0.2 to 0.25;
the refractive system and the reflective system satisfy the following relationship:
1.5<L1/L2<2；
the rear working distance of the projection lens meets the following relation:
0.2<BFL/L2<0.4；
wherein L1 denotes an overall length of the refractive system, L2 denotes a distance between the refractive system and the reflective system, and BFL denotes a rear working distance of the projection lens.
11. A projection system, comprising: a projection light source, a light valve modulating component and a projection lens according to any one of claims 1 to 10;
the projection light source is used for emitting light with different colors according to time sequence;
the light valve modulation component is positioned on the light emitting side of the projection light source and is used for modulating and reflecting incident light;
and the projection lens is positioned on a reflection light path of the light valve modulation component and is used for imaging emergent light of the light valve modulation component.
CN202111667597.1A 2021-12-31 2021-12-31 Projection lens and projection system Pending CN114114644A (en)

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PCT/CN2022/136659 WO2023124812A1 (en) 2021-12-31 2022-12-05 Projection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023124812A1 (en) * 2021-12-31 2023-07-06 青岛海信激光显示股份有限公司 Projection device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023124812A1 (en) * 2021-12-31 2023-07-06 青岛海信激光显示股份有限公司 Projection device

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