CN116088254B - Low-projection-ratio optical system - Google Patents
Low-projection-ratio optical system Download PDFInfo
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- CN116088254B CN116088254B CN202310368892.XA CN202310368892A CN116088254B CN 116088254 B CN116088254 B CN 116088254B CN 202310368892 A CN202310368892 A CN 202310368892A CN 116088254 B CN116088254 B CN 116088254B
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- 230000003287 optical effect Effects 0.000 title claims abstract description 35
- 230000004075 alteration Effects 0.000 claims description 35
- 239000011521 glass Substances 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 12
- 238000005286 illumination Methods 0.000 claims description 8
- 230000002708 enhancing effect Effects 0.000 claims description 3
- 238000003384 imaging method Methods 0.000 description 13
- 238000010586 diagram Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 4
- 201000009310 astigmatism Diseases 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 206010010071 Coma Diseases 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
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- 206010073261 Ovarian theca cell tumour Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 230000005499 meniscus Effects 0.000 description 1
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Classifications
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- 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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- 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
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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
- G02B13/0055—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
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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
- G02B13/0055—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
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- 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
- G03B21/005—Projectors using an electronic spatial light modulator but not peculiar thereto
- G03B21/008—Projectors using an electronic spatial light modulator but not peculiar thereto using micromirror devices
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- Optics & Photonics (AREA)
- Lenses (AREA)
Abstract
The invention discloses a low-projection-ratio optical system, which relates to the field of optical systems, and aims at solving the problem that cost and miniaturization cannot be simultaneously realized on the premise of ensuring image quality in lens design.
Description
Technical Field
The invention relates to the field of optical systems, in particular to a low-projection-ratio optical system.
Background
The projection display market is wide, but the lens is one of core technologies in projection display, the difficulty from design to processing is relatively high, and particularly, the cost and the miniaturization are simultaneously considered on the premise of ensuring the image quality, so that the lens is a great difficulty in lens design.
The technical scheme adopted by the existing ultra-short-focus projection lens uses a refraction and reflection mixing system, the projection distance can be shortened by using curved surface reflection of a reflection system, the projection ratio is generally designed to be 0.3-0.22 in order to reduce design difficulty and improve manufacturability in the market, a single system architecture is used, the synergistic effect among all groups is not fully exerted, so that the projection distance is not further reduced in large projection picture application, the angle of light entering a screen is increased, and higher requirements are put forward on the performance of the lens. In the conventional design scheme, when the projection condition with low projection ratio is adopted, the correction capability of marginal light is insufficient, particularly the degradation at the corner position of a picture is obvious, the problem of the degradation of the image quality of a large angle of a lens cannot be effectively improved, and the application scene of a product is influenced.
Therefore, it is needed to design an ultra-short focal lens with lower projection ratio to further improve the product performance.
Disclosure of Invention
Aiming at the problem that the design of the lens cannot simultaneously consider the cost and the miniaturization under the premise of ensuring the image quality, the invention provides a scheme of mixing a plurality of cemented lenses, glass aspheric surfaces and plastic aspheric surfaces, and focuses on adding the cemented lenses into the sub-lens groups, thereby effectively compensating the chromatic aberration of each group of the lens, reducing the difficulty of the compensation of the rear group of the lens, combining different reflecting surface forms and curvature control of the emergent surface, effectively balancing the aberration among the lens groups, reducing the sensitivity of the system and realizing shorter projection ratio under the condition of small volume.
The invention provides a low-projection ratio optical system, which particularly comprises a light valve, an illumination prism, an image offset mirror and a projection lens which are sequentially arranged, wherein the projection lens comprises a refraction system and a reflection system,
the refraction system consists of 1 glass aspheric mirror, 15 glass spherical mirrors and 1 plastic aspheric mirror, the 15 glass spherical mirrors consist of 4 double-cemented lenses, 1 triple-cemented lenses and 4 single lenses, and 1 double-cemented lens is placed in front of the plastic aspheric mirror, the triple-cemented lenses and the double-cemented lenses jointly realize correction of axial chromatic aberration and vertical chromatic aberration in the optical lens,
the reflection system comprises an 18 th lens, wherein the 18 th lens is an aspheric surface or a free-form surface reflecting mirror made of plastic materials, and an odd-even mixed aspheric equation is adopted for enhancing correction of marginal rays.
Further, the light valve is a DMD chip or an LCOS chip.
Further, the illumination prism is a TIR total reflection prism.
Further, the refraction system is sequentially composed of a first lens group, a second lens group and a third lens group, an aperture diaphragm is arranged between the first lens group and the second lens group, and is close to the second lens group,
the first lens group sequentially comprises the following components from the image offset mirror to the aperture diaphragm: the 1 st lens is a single lens, the 2 nd lens is a glass aspheric lens, the 3 rd lens, the 4 th lens and the 5 th lens are combined into a three-cemented lens, the 6 th lens is a single lens, the 7 th lens and the 8 th lens are combined into a double-cemented lens,
the second lens group sequentially comprises the following components from the aperture diaphragm to the 12 th lens: a double-cemented lens composed of a 9 th lens and a 10 th lens, a double-cemented lens composed of an 11 th lens and a 12 th lens,
the third lens group sequentially comprises the following components from the 13 th lens to the reflecting system: the 13 th lens is a single lens, the 14 th lens and the 15 th lens form a double-cemented lens, the 16 th lens is a plastic aspherical mirror, and the 17 th lens is a single lens.
Further, the parameters of the projection lens are as follows:
the Abbe number of the 4 th lens is selected to be 25-35, and the refractive index is 1.9-2.2;
the refractive index of the 7 th lens ranges from 1.9 to 2.2;
the Abbe number range of the 8 th lens is 40-50;
the Abbe number range of the 15 th lens is 20-28, and the refractive index range is 1.7-1.9;
the 16 th lens has a refractive index of 1.5;
the 18 th lens has a refractive index of 1.5.
Further, the refractive system is configured to provide, in response to a light beam, the power distribution of the lens from the 1 st lens to the 17 th lens is positive, negative, respectively positive, negative, positive, negative, the total focal power of the refraction system is positive focal power, and the total focal power of the reflection system is positive focal power.
Further, the refraction system and the reflection system generate positive diopter, and the total length L1 of the refraction system and the interval L2 between the refraction system and the reflection system satisfy the conditions: 0.5< L1/L2<2.
Further, the equivalent focal length F1 of the projection lens, the equivalent focal length F2 of the refraction system, and the equivalent focal length F3 of the reflection system satisfy the following conditions: 3< |F2/F1| <6,8< |F3/F1| <12.
Further, the distance BFL from the light valve to the 1 st lens satisfies the condition: 0.1< BFL/(L1+L2) <0.25.
Compared with the prior art, the invention has the beneficial effects that:
firstly, by adopting a scheme of mixing multiple cemented lenses, glass aspheric surfaces and plastic aspheric surfaces and combining different reflecting surface forms and curvature control of an emergent surface, the invention can effectively balance aberration among lens groups, reduce sensitivity of a system, realize that the total lens length of a small volume is only 190mm, realize a shorter projection ratio and realize a projection ratio of 0.18 under the condition of large aperture;
secondly, the cemented lens is added into the sub-lens groups, so that chromatic aberration of each group of the lens is effectively compensated, the difficulty of common back group lens compensation is reduced, a low projection ratio design scheme is realized, and the performance of the lens is improved by using a smaller volume;
third, the technical proposal of the invention has compact overall structure, realizes the imaging quality with low projection ratio and high resolution through the light valve, the spherical lens, the cemented lens, the reflector and reasonable material collocation, and simultaneously greatly improves the volume and manufacturability of the lens.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a low throw ratio optical system;
FIG. 2 is a schematic diagram of a refractive system;
FIG. 3 is a schematic diagram of an imaging optical path of a low throw ratio optical system;
fig. 4 is a spot diagram for different field of view conditions.
Reference numerals:
1. a light valve; 2. an illumination prism; 3. an image offset mirror; 4. a projection lens; 41. a refractive system; 411. a 1 st lens; 412. a 2 nd lens; 413. a 3 rd lens; 414. a 4 th lens; 415. a 5 th lens; 416. a 6 th lens; 417. a 7 th lens; 418. an 8 th lens; 419. a 9 th lens; 4110. a 10 th lens; 4111. 11 th lens; 4112. a 12 th lens; 4113. a 13 th lens; 4114. a 14 th lens; 4115. 15 th lens; 4116. a 16 th lens; 4117. a 17 th lens; 42. a reflection system; 421. an 18 th lens; 5. an aperture stop.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It will be appreciated by those of skill in the art that the following specific embodiments or implementations are provided as a series of preferred arrangements of the present invention for further explanation of the specific disclosure, and that the arrangements may be used in conjunction or association with each other, unless it is specifically contemplated that some or some of the specific embodiments or implementations may not be associated or used with other embodiments or implementations. Meanwhile, the following specific examples or embodiments are merely provided as an optimized arrangement, and are not to be construed as limiting the scope of the present invention.
The following describes specific embodiments of the present invention with reference to the drawings (tables).
According to the lens scheme, the scheme of mixing multiple cemented lenses, the glass aspheric surface and the plastic aspheric surface is adopted, the cemented lenses are mainly added to the sub-lens groups, chromatic aberration of each group of the lens is effectively compensated, the difficulty of common back group lens group compensation is reduced, a low projection ratio design scheme is realized, and the lens performance is improved by using a smaller volume. Fig. 1 is a schematic diagram of a low throw ratio optical system.
The invention provides a low-projection ratio optical system, which comprises a light valve 1, an illumination prism 2, an image offset lens 3 and a projection lens 4 which are sequentially arranged, wherein the light valve 1 is used for providing high-resolution image light beams, the illumination prism 2 is used for folding light paths, reducing the system volume, the image offset lens 3 is used for improving the resolution of the light beams, the projection lens 4 comprises a refraction system 41 and a reflection system 42,
the refraction system 41 is composed of 1 glass aspherical mirror, 15 glass spherical mirrors and 1 plastic aspherical mirror, and the 15 glass spherical mirrors are composed of 4 double cemented lenses, 1 triple cemented lens and 4 single lenses, and 1 double cemented lens is placed in front of the plastic aspherical mirror, the triple cemented lens and the double cemented lens are used for correcting axial chromatic aberration and vertical chromatic aberration in the optical lens,
the reflection system 42 includes an 18 th lens 421, which is an aspherical or freeform mirror of plastic material, and employs a parity-hybrid aspherical equation for enhancing correction of marginal rays.
The parity-hybrid aspherical equation formula is as follows:wherein,,
z is the sagittal value of the curved surface, c is the curvature, k is the conic coefficient, r is the caliber size, N is the order of the aspheric surface,α i is an aspheric coefficient, and ρ is the caliber after planning.
The light valve 1 is a DMD chip or an LCOS chip, and can provide high-resolution image light beams; the illumination prism 2 is a TIR total reflection prism, so that a folded light path is realized, the system volume is reduced, and the brightness and contrast of light entering the lens by the light valve 1 can be improved; the image offset mirror 3 can improve the beam resolution.
The refractive system 41 is composed of a first lens group, a second lens group, and a third lens group in this order, an aperture stop 5 is provided between the first lens group and the second lens group, and the aperture stop 5 is close to the second lens group, and fig. 2 is a schematic structural view of the refractive system.
The first lens group sequentially comprises the following components from the image offset lens 3 to the aperture diaphragm 5: lens 411, lens 412, lens 413, lens 414 and lens 415 are combined to form a three-cemented lens, lens 416, lens 411, lens 417 and lens 418 are combined to form a two-cemented lens,
the second lens group sequentially has the following directions from the aperture stop 5 to the 12 th lens 4112: a doublet lens composed of 9 th lens 419 and 10 th lens 4110, a doublet lens composed of 11 th lens 4111 and 12 th lens 4112,
the third lens group sequentially from the 13 th lens 4113 to the reflection system 42: the 13 th lens 4113 is a single lens, the 14 th lens 4114 and the 15 th lens 4115 are double cemented lenses, the 16 th lens 4116 is a plastic aspherical mirror, and the 17 th lens 4117 is a single lens.
The third lens group is the front group lens group of the system, and the first lens group and the second lens group are the rear group lens group of the system. The front group lens group is mainly responsible for correcting lens distortion and pushing light rays, and the 14 th lens 4114 and the 15 th lens 4115 are particularly combined into a cemented lens, so that the chromatic aberration correcting effect of the front group lens group is further improved, and the burden of correcting chromatic aberration of the rear group lens group is shared.
All lens groups and reflecting mirrors are the same optical axis, wherein the double-cemented lens and the triple-cemented lens play a key role in correcting the chromatic aberration of the system, and the triple-cemented lens and the double-cemented lens mainly correct the axial chromatic aberration and the vertical chromatic aberration in the optical lens. The lens assembly composed of the 14 th lens 4114 and the 15 th lens 4115 in front of the 16 th lens 4116 in the third lens group effectively shares the correction requirement of chromatic aberration of the whole system.
In the refractive lens system, three cemented lenses are used as core elements, glass materials and optical power distribution are reasonably selected to effectively balance aberration and processability while aberration correction is carried out, and the three cemented lenses are mainly used for correcting chromatic aberration and are preferably matched by materials with larger Abbe number difference.
The abbe number of the 4 th lens 414 is selected to be 25-35, and the abbe number of the material is selected to be 25-35, so that the blue light absorption of the material can be effectively reduced, the lens efficiency is improved, the value in practical application is 29.1, the refractive index is selected to be a larger glass material, the refractive index is 1.9-2.2, and meanwhile, the reduction of the transmittance is inhibited by considering that the thickness of the 4 th lens 414 is required to be 0.5-2 mm in design. The 3 rd lens 413 and the 5 th lens 415 are distributed with positive focal power, and materials with larger abbe numbers are selected, so that the high refractive index negative focal power of the 4 th lens 414 is neutralized, and aberration such as spherical aberration, coma aberration and astigmatism of the lens is reduced. In general, the higher the refractive index, the more the blue light is absorbed, the light transmittance is reduced, and in practical application, the refractive index of the 3 rd lens 413 and the 5 th lens 415 takes a value of 1.5, and the abbe number is 81;
the 7 th lens 417 and the 8 th lens 418 form a double-cemented lens, wherein the refractive index of the 7 th lens 417 ranges from 1.9 to 2.2, the abbe number of the 8 th lens 418 ranges from 40 to 50, and the reason for the selection is that the 7 th lens 417 and the 8 th lens 418 are close to the aperture stop 5, so that chromatic aberration is required to be corrected, and the influence of the spherical aberration is required to be reduced due to enough refractive index. In practical application, abbe numbers of the 7 th lens 417 and the 8 th lens 418 are respectively 29 and 44, and by designing the 7 th lens 417 and the 8 th lens 418 to be matched with biconcave and meniscus, a correspondence relationship is formed for the bicontinuous lens combined by the 9 th lens 419 and the 10 th lens 4110, and an approximate symmetrical form has an effective correcting effect on aberration;
the 11 th lens 4111 and the 12 th lens 4112 are combined into a double-cemented lens, so that the coma influence of the independent 11 th lens 4111 is reduced, the sensitivity of the lens is reduced, and the manufacturability of the lens is improved;
the 13 th lens 4113 to the 17 th lens 4117 are mainly responsible for correcting lens distortion and pushing light rays, the refractive index range of the 15 th lens 4115 is 1.7-1.9, and the Abbe number range is 20-28;
the 16 th lens 4116 has a refractive index of about 1.5, and by matching with the 17 th lens 4117, the distortion of the light entering the aspherical or freeform surface reflecting mirror is effectively corrected, the distortion correction range of the aspherical or freeform surface reflecting mirror is reduced, and the effect of shorter projection ratio is realized.
The 18 th lens 421 is an aspherical or free-form surface reflecting mirror made of plastic material, and has a refractive index of about 1.5. By controlling the distances between the 18 th lens 421 and the 16 th lens 4116, 17 th lens 4117, the projection ratio can be reduced, and the total length of the lens can be reduced.
In optical system imaging, there are mainly 5 kinds of monochromatic aberrations of spherical aberration, coma, astigmatism, field curvature, distortion, and 2 kinds of chromatic aberration of axial chromatic aberration and vertical chromatic aberration.
The focal power of the lens in the optical system can directly influence astigmatism, field curvature, distortion, axial chromatic aberration and vertical chromatic aberration, so that different positive and negative focal power collocations can play a certain role in aberration correction. In the present invention 17 lenses in the refractive system 41, the power distribution in the direction from the 1 st lens 411 to the 17 th lens 4117 is positive, negative positive, negative, positive, negative, positive negative, positive, negative; in the invention, the total focal power of the refraction lens group is positive focal power, and the aspherical or free-form surface reflecting mirror is also positive focal power.
In the present invention, the refractive system 41 and the reflective system 42 generate positive diopters (positive diopters are basic conditions for enabling imaging), the total length of the refractive system 41 is L1 (distance from the 1 st lens 411 to the 17 th lens 4117), the interval between the refractive system 41 and the reflective system 42 is L2, and the conditions are satisfied by L1 and L2: 0.5< L1/L2<2 to reduce the volume;
the equivalent focal length F1 of the projection lens 4, the equivalent focal length F2 of the refraction system 41, and the equivalent focal lengths F3, F1, F2, and F3 of the reflection system 42 satisfy the conditions: 3< |F2/F1| <6;8< |F3/F1| <12;
the distance from the light valve 1 to the 1 st lens 411, i.e. the rear working distance of the lens, is BFL, which satisfies the condition: 0.1< BFL/(L1+L2) <0.25 to satisfy the ultra-short focal characteristics of the lens.
The technical scheme of the invention is a secondary imaging architecture, the pixel surface of the light valve 1 is an object plane, after the light valve 1 reflects the light beam and passes through the refraction system 41, the first imaging is carried out between the 18 th lens 421 and the refraction system 41 (the first imaging is the first imaging when the light beam forms a convergence point), after the first imaging is reflected by the 18 th lens 421, a secondary undistorted image is formed on the screen, the secondary imaging is carried out, and a large-size projection image is displayed on the projection screen.
The technical scheme of the invention has compact integral mechanism, realizes imaging quality with low projection ratio and high resolution through the light valve 1, the spherical lens, the cemented lens, the reflecting mirror and reasonable material collocation, and simultaneously greatly improves the volume and manufacturability of the lens.
In one embodiment, FIG. 3 is a schematic diagram of the imaging optical path of a low throw ratio optical system.
When the projection picture of the projection lens is 100 inches, the linear relation between the linear distance of the reflecting mirror and the screen and the length of the projection picture is that: the projection distance/screen length size is less than or equal to 0.18, namely the projection ratio is less than or equal to 0.18.
The low projection ratio optical system structural parameters satisfy the following conditions: effective Focal Length (EFL) =1.73 mm, offset of 130% < offset <150%, resolution of 93lp/mm, projected screen of 80 to 120 inches, and projection ratio of 0.18 to 0.2.
Fig. 4 is a spot diagram under different view field conditions, and is schematically shown as spot imaging diagrams of three different wavelength light rays (0.45 μm, 0.55 μm and 0.62 μm) on a screen under a certain view field condition under the normalized different view field conditions. The smaller the aberration, the smaller the spot, the RMS Radius is the root mean square Radius, and the actual spot size of the system can be quantitatively reflected. The root mean square radii of the graphs are shown in table 1:
TABLE 1 root mean square radius of spot under different field conditions
| Area (1) | Area (2) | Area (3) | Area (4) | Area (5) | Area (6) | |
| Root mean square radius (mum) | 1.927 | 1.561 | 1.743 | 2.123 | 2.070 | 1.789 |
| Area (7) | Area (8) | Area (9) | Area (10) | Area (11) | ||
| Root mean square radius (mum) | 1.803 | 2.108 | 2.195 | 1.981 | 2.089 |
As can be seen from Table 1, the root mean square radius of the spot under different view field conditions is 2.195 μm at maximum, and the actual spot size of the system is smaller than 2.7 μm in practice, which indicates that the good image quality effect in the examples is shown.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (8)
1. The low-projection-ratio optical system is characterized by comprising a light valve (1), an illumination prism (2), an image offset mirror (3) and a projection lens (4) which are sequentially arranged, wherein the projection lens (4) comprises a refraction system (41) and a reflection system (42),
the refraction system (41) consists of 1 glass aspheric mirror, 15 glass spherical mirrors and 1 plastic aspheric mirror, the 15 glass spherical mirrors consist of 4 double-cemented lenses, 1 triple-cemented lenses and 4 single lenses, and the 1 double-cemented lenses are placed in front of the plastic aspheric mirrors, the triple-cemented lenses and the double-cemented lenses jointly realize the correction of the axial chromatic aberration and the vertical chromatic aberration in the optical lens,
the refraction system (41) is sequentially composed of a first lens group, a second lens group and a third lens group, an aperture diaphragm (5) is arranged between the first lens group and the second lens group, the aperture diaphragm (5) is close to the second lens,
the first lens group sequentially comprises the following components from the image offset lens (3) to the aperture diaphragm (5): the 1 st lens (411) is a single lens, the 2 nd lens (412) is a glass aspheric lens, the 3 rd, 4 th and 5 th lenses are combined into a three-cemented lens (413), the 6 th lens (414) is a single lens, the 7 th and 8 th lenses are combined into a double-cemented lens (415),
the second lens group sequentially comprises the following components from an aperture diaphragm (5) to a 12 th lens: a doublet lens (416) composed of 9 th and 10 th lenses, a doublet lens (417) composed of 11 th and 12 th lenses,
the third lens group sequentially comprises the following components from the 13 th lens to the reflecting system (42): the 13 th lens (418) is a single lens, the 14 th and 15 th lenses are composed of a double-cemented lens (419), the 16 th lens (4110) is a plastic aspherical mirror, the 17 th lens (4111) is a single lens,
the reflection system (42) comprises an 18 th lens (421), wherein the 18 th lens (421) is an aspheric or free-form surface reflecting mirror made of plastic materials, and an odd-even mixed aspheric equation is adopted for enhancing the correction of marginal rays.
2. A low throw ratio optical system according to claim 1, characterized in that the light valve (1) is a DMD chip or a LCos chip.
3. A low throw ratio optical system according to claim 1, characterized in that the illumination prism (2) is a TIR total reflection prism.
4. A low throw ratio optical system according to claim 1, characterized in that the parameters of the projection lens (4) are:
the Abbe number of the 4 th lens is selected to be 25-35, and the refractive index is 1.9-2.2;
the refractive index of the 7 th lens ranges from 1.9 to 2.2;
the Abbe number range of the 8 th lens is 40-50;
the Abbe number range of the 15 th lens is 20-28, and the refractive index range is 1.7-1.9;
the 16 th lens (4110) has a refractive index of 1.5;
the 18 th lens (421) has a refractive index of 1.5.
5. A low throw ratio optical system according to claim 1, wherein the refractive system (41), the power distribution of the lens from the first lens (411) to the 17 th lens (4111) is positive, respectively positive, negative, positive, negative, the total optical power of the refraction system (41) is positive optical power, and the total optical power of the reflection system (42) is positive optical power.
6. A low throw ratio optical system according to claim 1, wherein the refractive system (41) and the reflective system (42) produce positive refractive power, the total length L1 of the refractive system (41), the spacing L2 between the refractive system (41) and the reflective system (42) satisfying the condition: 0.5< L1/L2<2.
7. A low throw ratio optical system according to claim 1, wherein the equivalent focal length F1 of the projection lens (4), the equivalent focal length F2 of the refractive system (41), and the equivalent focal length F3 of the reflective system (42) satisfy the condition: 3< |F2/F1| <6,8< |F3/F1| <12.
8. A low throw ratio optical system according to claim 1, characterized in that the distance BFL of the light valve (1) to the 1 st lens (411) fulfils the condition: 0.1< BFL/(L1+L2) <0.25.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310368892.XA CN116088254B (en) | 2023-04-10 | 2023-04-10 | Low-projection-ratio optical system |
| PCT/CN2023/100082 WO2024212344A1 (en) | 2023-04-10 | 2023-06-14 | Low throw ratio optical system |
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| CN202310368892.XA CN116088254B (en) | 2023-04-10 | 2023-04-10 | Low-projection-ratio optical system |
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| CN116088254B (en) * | 2023-04-10 | 2023-08-08 | 沂普光电(天津)有限公司 | Low-projection-ratio optical system |
| CN116819730B (en) * | 2023-06-30 | 2024-01-26 | 梅卡曼德（北京）机器人科技有限公司 | Momer lens and electronic equipment |
| CN116577911B (en) * | 2023-07-14 | 2023-09-29 | 沂普光电(天津)有限公司 | High-definition low-projection-ratio miniaturized projection lens |
| CN116643409B (en) * | 2023-07-18 | 2023-10-20 | 沂普光电(天津)有限公司 | Optical display system of AR head display |
| CN118244454B (en) * | 2024-05-23 | 2024-08-20 | 沂普光电(天津)有限公司 | Small-volume long-focus projection system |
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| CN112987264A (en) * | 2021-04-26 | 2021-06-18 | 黄国豹 | Ultra-short-focus projection lens with large view field and high brightness |
| CN114296217A (en) * | 2021-12-29 | 2022-04-08 | 青岛海信激光显示股份有限公司 | Projection lens and projection system |
| CN114296220A (en) * | 2021-12-31 | 2022-04-08 | 青岛海信激光显示股份有限公司 | Projection lens and projection system |
| CN115657275A (en) * | 2022-12-12 | 2023-01-31 | 沂普光电(天津)有限公司 | Ultra-short-focus projection lens and projection system |
| CN115793361A (en) * | 2023-02-01 | 2023-03-14 | 沂普光电(天津)有限公司 | Ultra-short-focus projection lens and system |
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| JP2011033737A (en) * | 2009-07-30 | 2011-02-17 | Fujifilm Corp | Projection optical system and projection type display using the same |
| CN103777314B (en) * | 2012-10-25 | 2017-10-13 | 扬明光学股份有限公司 | wide angle projection lens |
| JP5930088B1 (en) * | 2015-02-18 | 2016-06-08 | セイコーエプソン株式会社 | Projection optical system |
| CN108303784A (en) * | 2018-03-27 | 2018-07-20 | 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 |
| CN112444932B (en) * | 2019-09-04 | 2022-06-03 | 青岛海信激光显示股份有限公司 | Projection lens, focusing method and device of projection lens and projector |
| CN114545589A (en) * | 2020-11-26 | 2022-05-27 | 青岛海信激光显示股份有限公司 | Projection Lenses and Projection Equipment |
| CN112764208B (en) * | 2021-01-13 | 2024-09-03 | 中山联合光电科技股份有限公司 | Optical system and projection equipment |
| CN114296218A (en) * | 2021-12-29 | 2022-04-08 | 青岛海信激光显示股份有限公司 | Projection lens and projection system |
| CN116088254B (en) * | 2023-04-10 | 2023-08-08 | 沂普光电(天津)有限公司 | Low-projection-ratio optical system |
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- 2023-04-10 CN CN202310368892.XA patent/CN116088254B/en active Active
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| CN112987264A (en) * | 2021-04-26 | 2021-06-18 | 黄国豹 | Ultra-short-focus projection lens with large view field and high brightness |
| CN114296217A (en) * | 2021-12-29 | 2022-04-08 | 青岛海信激光显示股份有限公司 | Projection lens and projection system |
| CN114296220A (en) * | 2021-12-31 | 2022-04-08 | 青岛海信激光显示股份有限公司 | Projection lens and projection system |
| CN115657275A (en) * | 2022-12-12 | 2023-01-31 | 沂普光电(天津)有限公司 | Ultra-short-focus projection lens and projection system |
| CN115793361A (en) * | 2023-02-01 | 2023-03-14 | 沂普光电(天津)有限公司 | Ultra-short-focus projection lens and system |
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| CN116088254A (en) | 2023-05-09 |
| WO2024212344A1 (en) | 2024-10-17 |
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