CN113946028B - Projection lens and projection device - Google Patents
Projection lens and projection device Download PDFInfo
- Publication number
- CN113946028B CN113946028B CN202111558516.4A CN202111558516A CN113946028B CN 113946028 B CN113946028 B CN 113946028B CN 202111558516 A CN202111558516 A CN 202111558516A CN 113946028 B CN113946028 B CN 113946028B
- Authority
- CN
- China
- Prior art keywords
- lens
- projection lens
- projection
- light
- optical power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- G02B13/18—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
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
- G02B7/028—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Lenses (AREA)
Abstract
The invention discloses a projection lens and a projection device, wherein the projection lens is used for projecting light rays of an image source surface to a projection surface, and the projection lens sequentially comprises the following components in the light propagation direction: a first group having a positive optical power, a diaphragm, a second group having a negative optical power; and the projection lens meets the conditional expression: -2.5<fⅠ/fⅡ<-0.5; wherein f isⅠRepresenting the combined focal length of the first group, fⅡRepresenting a combined focal length of the second group. The projection lens at least has the advantages of good imaging quality, low distortion and small chromatic aberration.
Description
Technical Field
The present invention relates to the field of imaging lenses, and in particular, to a projection lens and a projection apparatus.
Background
With the popularization of automobiles, no matter whether the automobiles run in urban traffic or on expressways, traffic accidents caused by looking at instruments or intelligent equipment at low heads during driving are common. In urban traffic, because the speed limit of various road conditions is different, a driver often needs to look over navigation or an instrument panel by lowering head, and the driving process of the highway is equivalent to twenty-thirty meters for blind driving for the first time, and the behaviors can seriously affect the driving safety. In order to reduce the risk of the driver walking blind down, navigation heads-Up displays (Head Up Display abbreviated HUD) are being used in more and more cars. The HUD is a transparent display, and can directly project driving information into a sight range of a driver (such as in a windshield or on a screen) so that the driver can focus on the outside of a vehicle during driving.
The HUD principle is similar to slide projection, and is mainly implemented by using reflection and virtual imaging principles in optical imaging: according to the information provided by the vehicle-mounted system, the projector sends out images, the images are reflected to the projection lens through the reflector and then reflected to the windshield glass or the screen through the projection lens, at the moment, a driver sees a virtual image about 2 meters in front of eyes, and the information is seemingly suspended on the front road. Because HUD has reduced the driver by a wide margin and has looked over the frequency of instrument down, need not adjust sight "focus" between observing distant place target and near instrument moreover, has improved driving safety nature and visual response speed, therefore HUD is more and more popularized in the application of driving safety field, but the ordinary projection lens on the existing market is not applicable to on-vehicle HUD environment. A projection lens for HUD on the market is because the restriction of lens figure, and the resolving power that the camera lens exists is not enough, and marginal visual field distortion is great, and the chromatic aberration defect such as big is difficult to satisfy high-end HUD's user demand.
Disclosure of Invention
Therefore, an object of the present invention is to provide a projection lens and a projection apparatus, which have at least the advantages of good image quality, low distortion and small chromatic aberration.
The embodiment of the invention implements the above object by the following technical scheme.
In a first aspect, the present invention provides a projection lens, where the projection lens is configured to project light from an image source surface onto a projection surface, and the projection lens sequentially includes, along a light propagation direction: a first group with positive optical power, a diaphragm, a second group with negative optical power; and the projection lens meets the conditional expression:
-2.5< fⅠ/fⅡ< -0.5；
wherein, fⅠRepresenting the combined focal length of the first group, fⅡRepresenting a combined focal length of the second group.
In a second aspect, the present invention provides a projection apparatus, including an image source and the projection lens provided in the first aspect, wherein the image source is configured to emit light, and the projection lens is disposed in an emergent direction of the emitted light of the image source.
The projection lens provided by the invention can be applied to a vehicle-mounted HUD, when the projection lens works, a vehicle-mounted system projects modulated signal light (light emitted by an image source) into the projection lens, and the light is projected on a screen through the first group, the diaphragm and the second group in sequence to obtain a projection picture.
Compared with the prior art, the projection lens provided by the invention has the advantages that the focal powers of seven lenses are reasonably matched, so that the lens can realize clear projection pictures at positions of 120-140 mm; due to the adoption of the all-glass lens, the lens has good thermal stability, and can effectively compensate image plane offset caused by thermal expansion of the lens at minus 40 ℃ to plus 105 ℃; the first lens adopts the aspheric glass lens, so that the imaging quality of the lens is greatly improved while the miniaturization of the lens is met; meanwhile, the focal power of each lens before and after the diaphragm is reasonably set, so that the distortion and chromatic aberration of the lens are well corrected.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic structural diagram of a projection lens according to a first embodiment of the present invention;
FIG. 2 is a distortion curve diagram of a projection lens according to a first embodiment of the present invention;
FIG. 3 is a MTF graph of the projection lens of the first embodiment of the present invention in the working band;
FIG. 4 is a vertical axis chromatic aberration diagram of a projection lens according to a first embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a projection lens according to a second embodiment of the present invention;
FIG. 6 is a distortion curve diagram of a projection lens according to a second embodiment of the present invention;
FIG. 7 is a MTF curve of a projection lens in a working band according to a second embodiment of the present invention;
FIG. 8 is a vertical axis chromatic aberration diagram of a projection lens according to a second embodiment of the present invention;
FIG. 9 is a schematic structural diagram of a projection lens according to a third embodiment of the present invention;
FIG. 10 is a distortion graph of a projection lens according to a third embodiment of the present invention;
FIG. 11 is a MTF graph of a projection lens in a working band according to a third embodiment of the present invention;
FIG. 12 is a vertical axis chromatic aberration diagram of a projection lens according to a third embodiment of the present invention;
FIG. 13 is a schematic structural diagram of a projection lens according to a fourth embodiment of the present invention;
FIG. 14 is a distortion curve diagram of a projection lens according to a fourth embodiment of the present invention;
FIG. 15 is a MTF graph of a projection lens of a fourth embodiment of the present invention in an operating band;
fig. 16 is a vertical axis chromatic aberration diagram of a projection lens according to a fourth embodiment of the present invention.
Detailed Description
In order to make the objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. Several embodiments of the invention are presented in the drawings. This invention 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.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.
The invention provides a projection lens, which is used for projecting light of an image source surface to a projection surface, wherein the image source surface is used for displaying an image to be projected, and the projection surface is used for displaying a projected image. Projection lens includes in proper order along light propagation direction: a first group having a positive optical power, a diaphragm, a second group having a negative optical power; and the projection lens meets the conditional expression:
-2.5< fⅠ/fⅡ< -0.5；
wherein f isⅠDenotes the combined focal length of the first group, fⅡRepresenting the combined focal length of the second group. When the projection lens works, light rays sequentially pass through the first group and the second group, and the light rays can be focused within a short distance due to the fact that the first group has positive focal power; the second group has negative focal power, so that light rays can be diffused out after passing through the second group and can be better projected onto a projection surface; the condition is satisfied, the ratio of the focal lengths of the first group and the second group is reasonably distributed, so that the telecentricity of the projection lens is favorably controlled and guaranteedThe size of the projection picture is ensured to be larger, and meanwhile, the projection can be completed within a shorter projection distance.
Specifically, the first group in the projection lens sequentially includes along a light propagation direction:
the light-emitting device comprises a first lens with positive focal power, wherein the light-in surface and the light-out surface of the first lens are convex surfaces;
the second lens has positive focal power, and the light-emitting surface of the second lens is a convex surface;
the light emitting surface of the third lens is a concave surface;
the light incident surface and the light emergent surface of the fourth lens are convex surfaces, and the third lens and the fourth lens form a cemented lens;
the second group in the projection lens sequentially comprises along the light propagation direction:
the light incident surface of the fifth lens is a concave surface;
the light incident surface of the sixth lens is a concave surface;
and the light emitting surface of the seventh lens is a convex surface.
Wherein the first lens is an aspheric lens. The first lens adopts an aspheric surface design, so that light rays near an optical axis and light rays at the edge of the lens can form images on the same surface, and aberration is reduced. Other lenses in the projection lens can adopt spherical lenses or aspherical lenses.
In order to enable the lens to have good thermal stability, all lenses in the projection lens can be made of glass lenses, so that image plane deviation caused by thermal expansion of the lens at minus 40 ℃ to plus 105 ℃ can be effectively compensated; in other embodiments, in order to effectively reduce the cost and volume of the lens, the projection lens can adopt a glass-plastic mixed matching mode, and can also obtain good imaging effect and thermal stability.
In some embodiments, the projection lens satisfies the conditional expression:
20mm<BFL<30mm；
120mm<TD<140mm；
the BFL represents an axial distance between an image source surface of the projection lens and a light incident surface of the first lens, and the TD represents an axial distance between a light emitting surface of the seventh lens and a projection surface of the projection lens, that is, the TD represents a projection distance of the projection lens. The condition formula is met, on one hand, a proper distance is kept between the image source surface and the front end of the projection lens, and the interference between different parts in the assembling process is reduced; on the other hand makes projection lens can realize the projection of high definition on the screen apart from 120mm ~140mm, can satisfy the inside limited space of on-vehicle HUD.
In some embodiments, the projection lens satisfies the conditional expression:
0.9<f/(IH/tanθ)<1.1；（1）
13.5 mm/rad<IH/θ<15.5 mm/rad；（2）
wherein f represents the effective focal length of the projection lens, theta represents the maximum half field angle of the light emitted by the projection lens, and IH represents half of the diagonal of the projection lens opposite to the image source. The distortion of the lens can be effectively improved and the resolution of the lens in the whole field of view can be improved by satisfying the conditional expressions (1) and (2).
In some embodiments, the projection lens satisfies the conditional expression:
BFL/TTL>0.3；（3）
wherein, TTL represents the total optical length of the projection lens, that is, the axial distance from the image source surface to the light exit surface of the seventh lens in the projection lens, and BFL represents the axial distance from the image source surface of the projection lens to the light entrance surface of the first lens. Satisfying the above conditional expression (3), the image source plane and the front end of the projection lens can be kept in a longer space, the space for placing other optical projection elements (such as a reflector or a light splitting device) is ensured, and interference with other element mechanisms is avoided.
In some embodiments, the projection lens satisfies the conditional expression:
-3.0<R22/f2<-0.1；（4）
wherein R22 denotes a radius of curvature of the light exit surface of the second lens, and f2 denotes an effective focal length of the second lens. The condition formula (4) is satisfied, the inclination angle of the edge of the lens is reduced by controlling the curvature radius of the lens, the uniformity of film coating is facilitated, and the generation of high-energy ghost is reduced.
In some embodiments, the projection lens satisfies the conditional expression:
0.35<φ1/φ<1；（5）
0.3<φ2/φ<1；（6）
wherein φ 1 represents the focal power of the first lens, φ 2 represents the focal power of the second lens, and φ represents the focal power of the projection lens. The optical power ratio of the first lens and the second lens is reasonably set, so that light rays on the image source side collected by the first lens can be smoothly transited to the second lens and the rear part of the lens, the correction of subsequent lens aberration is facilitated, and the imaging quality of the lens is improved.
In some embodiments, the projection lens satisfies the conditional expression:
-2＜φ5/φ＜-0.2；（7）
-2＜φ6/φ＜-0.2；（8）
0.2<φ7/φ<1；（9）
where φ 5 represents the focal power of the fifth lens, φ 6 represents the focal power of the sixth lens, φ 7 represents the focal power of the seventh lens, and φ represents the focal power of the projection lens. Satisfy above-mentioned conditional expression (7) to (9), can rationally distribute the positive and negative focal power of each lens in the second group and account for than, can make light carry out divergence of great degree behind the second group to make the size of projection picture enough big, better satisfy on-vehicle HUD's user demand.
In some embodiments, the projection lens satisfies the conditional expression:
Nd3>1.8，Vd3<45；（12）
Nd4<1.7，Vd4>50；（13）
-1.5<φ3/φ4<-1；（14）
where Nd3 denotes a refractive index of a material of the third lens, Vd3 denotes an abbe number of the material of the third lens, Nd4 denotes a refractive index of a material of the fourth lens, Vd4 denotes an abbe number of the material of the fourth lens, ± 3 denotes an optical power of the third lens, and Φ 4 denotes an optical power of the fourth lens. By combining the third lens having a negative refractive power with a high refractive index and a low abbe number and the fourth lens having a positive refractive power with a low refractive index and a high abbe number into a cemented lens, the chromatic aberration of the projection lens can be significantly improved, while satisfying the above conditional expressions (12) to (14).
In some embodiments, the projection lens satisfies the conditional expression:
-15×10-6/℃< (dn/dt)1+(dn/dt)4 +(dn/dt)6<-2×10-6/℃；（15）
wherein, (dn/dt)1 represents a temperature coefficient of refractive index of the material of the first lens, (dn/dt)4 represents a temperature coefficient of refractive index of the material of the fourth lens, and (dn/dt)6 represents a temperature coefficient of refractive index of the material of the sixth lens. The condition formula (15) is met, the thermal focal shift constructed by a complementary mechanical structure of the lens can be effectively compensated by reasonably distributing the lens material with the negative temperature coefficient of the refractive index, and the projection lens is ensured to have stable imaging performance in the environment of minus 40 ℃ to plus 105 ℃.
The invention is further illustrated below in the following examples. In each embodiment, the thickness, the curvature radius, and the material selection part of each lens in the projection lens are different, and the specific difference can be referred to the parameter table of each embodiment. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the innovative points of the present invention should be construed as being equivalent substitutions and shall be included within the scope of the present invention.
In the embodiments of the present invention, when the lens in the projection lens is an aspheric lens, the aspheric surface type of the lens satisfies the following equation:
wherein z represents the distance in the optical axis direction from the curved surface vertex, c represents the curvature of the curved surface vertex, K represents the conic coefficient, h represents the distance from the optical axis to the curved surface, and B, C, D, E and F represent the fourth, sixth, eighth, tenth and twelfth order curved surface coefficients, respectively. .
First embodiment
Referring to fig. 1, a schematic structural diagram of a projection lens 100 according to a first embodiment of the present disclosure is shown, where the projection lens 100 is used for projecting light from an image source to a projection plane. The projection lens 100 sequentially includes along a light propagation direction: a first group Q1 with positive power, diaphragm ST, a second group Q2 with negative power. Wherein, the first group Q1 includes in order along the light propagation direction: a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4; the second group Q2 sequentially comprises, in the direction of propagation of the light: a fifth lens L5, a sixth lens L6, and a seventh lens L7. The surface where the light enters is set as the light incident surface of the lens, and the surface where the light exits is set as the light exiting surface of the lens.
Specifically, the first lens L1 of the projection lens 100 has positive focal power, and both the light incident surface S1 and the light emitting surface S2 of the first lens are convex surfaces;
the second lens L2 has positive focal power, the light incident surface S3 of the second lens is a concave surface, and the light emergent surface S4 of the second lens is a convex surface;
the third lens L3 has negative focal power, the light incident surface S5 and the light emergent surface of the third lens are both concave surfaces, and the third lens L3 can be made of heavy lanthanum flint with high refractive index and low Abbe number;
the fourth lens L4 has positive focal power, the light incident surface and the light emitting surface S7 of the fourth lens are convex surfaces, and the fourth lens L4 may be made of crown glass with low refractive index and high abbe number; in order to better correct chromatic aberration of the system, the light-emitting surface of the third lens L3 and the light-entering surface of the fourth lens L4 are cemented into a cemented lens, and the cemented surface is S6;
the fifth lens L5 has negative focal power, and the light incident surface S8 and the light emitting surface S9 of the fifth lens are both concave surfaces;
the sixth lens L6 has negative focal power, and the light incident surface S10 and the light emitting surface S11 of the sixth lens are both concave surfaces;
the seventh lens L7 has positive refractive power, and the light incident surface S12 and the light emitting surface S13 of the seventh lens are both convex surfaces.
The first lens L1 is a glass aspheric lens, and the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all glass spherical lenses.
The parameters of the projection lens 100 provided in this embodiment are shown in table 1.
TABLE 1
The aspheric parameters of the projection lens 100 in this embodiment are shown in table 2.
TABLE 2
In the present embodiment, graphs of distortion of the projection lens 100, MTF in the operating band, and vertical axis chromatic aberration are shown in fig. 2, 3, and 4, respectively.
As can be seen from fig. 2, the f-tan θ distortion of the projection lens 100 at the main wavelength is within ± 1.5%, which indicates that the distortion of the projection lens 100 is well corrected.
As can be seen from FIG. 3, in the operating band of the projection lens 100, the MTF of the central field reaches 59% at 90lp/mm, and the MTF of the peripheral field reaches 41% at 90 lp/mm. The projection lens 100 has high resolution in the operating band.
As can be seen from FIG. 4, the vertical chromatic aberration of the projection lens 100 at 455nm, 555nm and 625nm is not more than 3 μm, which indicates that the vertical chromatic aberration of the projection lens 100 is well corrected.
Second embodiment
Referring to fig. 5, a schematic structural diagram of a projection lens 200 according to a second embodiment of the present invention is shown, where the structure of the projection lens 200 in this embodiment is substantially the same as that of the projection lens 100 in the first embodiment, except that the curvature radius, thickness, and material selection of each lens of the optical imaging lens in this embodiment are different.
Specifically, in the present embodiment, the first lens L1 of the projection lens 200 has positive focal power, and both the light incident surface S1 and the light emitting surface S2 of the first lens are convex surfaces;
the second lens L2 has positive focal power, the light incident surface S3 of the second lens is a convex surface, and the light emergent surface S4 of the second lens is a convex surface;
the third lens L3 has negative focal power, and the light incident surface S5 and the light emitting surface of the third lens are both concave surfaces;
the fourth lens L4 has positive focal power, the light incident surface and the light exit surface S7 of the fourth lens are both convex surfaces, and the light exit surface of the third lens L3 and the light incident surface of the fourth lens L4 are cemented into a cemented lens, and the cemented surface is S6;
the fifth lens L5 has negative focal power, the light incident surface S8 of the fifth lens is a concave surface, and the light emergent surface S9 of the fifth lens is a convex surface;
the sixth lens L6 has negative focal power, the light incident surface S10 of the sixth lens is a concave surface, and the light emergent surface S11 of the sixth lens is a convex surface;
the seventh lens L7 has positive refractive power, the light incident surface S12 of the seventh lens is a concave surface, and the light emitting surface S13 of the seventh lens is a convex surface.
The first lens L1 is a glass aspheric lens, and the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all glass spherical lenses.
The relevant parameters of the respective lenses of the projection lens 200 are shown in table 3.
TABLE 3
The aspherical surface parameters of the projection lens 200 in this embodiment are shown in table 4.
TABLE 4
In the present embodiment, graphs of distortion of the projection lens 200, MTF in the operating band, and vertical axis chromatic aberration are shown in fig. 6, 7, and 8, respectively.
As can be seen from fig. 6, the f-tan θ distortion of the projection lens 200 at the main wavelength is within ± 1.7%, which indicates that the distortion of the projection lens 200 is well corrected.
As can be seen from FIG. 7, the MTF of the central field of view of the projection lens 200 in the operating band reaches 58% at 90lp/mm, and the MTF of the peripheral field of view reaches 42% at 90 lp/mm. The projection lens 200 has high resolution in the operating band.
As can be seen from FIG. 8, the vertical axis chromatic aberration of the projection lens 200 between 455nm, 555nm and 625nm is not more than 3.5 μm, which indicates that the vertical axis chromatic aberration of the projection lens 200 is well corrected.
Third embodiment
Referring to fig. 9, a schematic structural diagram of a projection lens 300 according to a third embodiment of the present invention is shown, where the projection lens 300 in this embodiment has a structure substantially the same as that of the projection lens 200 in the second embodiment, except that curvature radius, thickness and material selection of each lens are different, and specific relevant parameters of each lens are shown in table 5.
TABLE 5
The aspherical surface parameters of the projection lens 300 in this embodiment are shown in table 6.
TABLE 6
In the present embodiment, graphs of distortion of the projection lens 300, MTF in the operating band, and vertical axis chromatic aberration are shown in fig. 10, 11, and 12, respectively.
As can be seen from fig. 10, the f-tan θ distortion of the projection lens 300 at the main wavelength is within ± 1.5%, which indicates that the distortion of the projection lens 300 is well corrected.
As can be seen from FIG. 11, the MTF of the central field of view of the projection lens 300 in the operating band reaches 64% at 90lp/mm, and the MTF of the peripheral field of view reaches 42% at 50 lp/mm. The projection lens 300 is illustrated as having high resolution in the operating band.
As can be seen from FIG. 12, the vertical axis chromatic aberration of the projection lens 300 between 455nm, 555nm and 625nm is not more than 3.0 μm, which indicates that the vertical axis chromatic aberration of the projection lens 300 is well corrected.
Fourth embodiment
Referring to fig. 13, a schematic view of a structure of a projection lens 400 according to a fourth embodiment of the present invention is shown, where the projection lens 400 in this embodiment has a structure that is substantially the same as that of the projection lens 100 in the first embodiment, and the difference is that a light incident surface S3 of a second lens L2 of the projection lens 400 in this embodiment is a convex surface, a light incident surface S5 of a third lens L3 is a convex surface, a light emitting surface S11 of a sixth lens L6 is a convex surface, a light incident surface S12 of a seventh lens is a concave surface, and curvature radii, thicknesses and material choices of the lenses are different, and specific parameters related to the lenses are shown in table 7.
TABLE 7
The aspherical surface parameters of the projection lens 400 in this embodiment are shown in table 8.
TABLE 8
In the present embodiment, graphs of distortion of the projection lens 400, MTF in the operating band, and vertical axis chromatic aberration are shown in fig. 14, 15, and 16, respectively.
As can be seen from fig. 14, the f-tan θ distortion of the projection lens 400 at the dominant wavelength is within ± 1.5%, indicating that the distortion of the lens is well corrected.
As can be seen from FIG. 15, the MTF of the central field of view of the projection lens 400 in the operating band reaches 68% at 90lp/mm, and the MTF of the peripheral field of view reaches 50% at 90 lp/mm. The projection lens 400 is illustrated as having high resolution in the operating band.
As can be seen from fig. 16, the vertical axis chromatic aberration of the projection lens 400 between 455nm, 555nm and 625nm is within ± 3.5 μm, which indicates that the vertical axis chromatic aberration of the projection lens 400 is well corrected.
Table 9 shows the four embodiments and their corresponding optical characteristics, including the effective focal length F, F #, the field angle 2 θ, the total optical length TTL, and the values corresponding to the above conditional expressions.
TABLE 9
For a projection lens, the projection ratio refers to the ratio between the projection distance and the horizontal size of the projection picture; the smaller the ratio, the larger the width of the projected image, indicating the same projection distance. Specifically, in the above embodiments, the projection ratio of the projection lens is 1.45, which indicates that the projection lens can project a large projection screen within a short projection distance.
By combining the above embodiments, the projection lens provided by the present invention has at least the following advantages:
(1) the projection lens provided by the invention can effectively compensate the thermal focus shift caused by a mechanical structure by reasonably matching the materials and the focal power of the seven glass lenses, so that the lens has excellent optical performance in the environment of minus 40 ℃ to plus 105 ℃.
(2) The first group in front of the diaphragm in the projection lens is mainly responsible for correcting the aberration of the optical system, and is beneficial to collecting light rays and amplifying the light rays to a projection surface when the light rays smoothly enter a subsequent optical system, and the lens can have high-definition projection quality by reasonably matching the material selection of the lenses before and after the diaphragm.
(3) The projection lens provided by the invention adopts a bonding body of the heavy lanthanum flint lens with negative focal power and the crown glass lens with positive focal power, can well correct the chromatic aberration of a system, and avoids the phenomenon of purple edge or red edge when the projection lens performs projection imaging.
Fifth embodiment
A fifth embodiment of the present invention provides a projection apparatus, which includes an image source and a projection lens (for example, the projection lens 100) in any of the embodiments, where the image source is configured to emit light, and the projection lens is disposed in an emergent direction of the emitted light of the image source.
The projection apparatus provided by the embodiment includes the projection lens 100, and since the projection lens 100 has the advantages of good imaging quality, low distortion and small chromatic aberration, the projection apparatus having the projection lens 100 also has the advantages of good imaging quality, low distortion and small chromatic aberration.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (11)
1. The projection lens is characterized in that the projection lens is used for projecting light rays of an image source surface to a projection surface, and the projection lens sequentially comprises the following components in the light propagation direction: a first group having a positive optical power, a diaphragm, a second group having a negative optical power; and the projection lens meets the conditional expression:
-2.5< fⅠ/fⅡ< -0.5；
wherein f isⅠRepresenting the combined focal length of the first group, fⅡRepresenting a combined focal length of the second group;
the first group has four lenses, includes in proper order along the light propagation direction:
a first lens having a positive optical power;
a second lens having a positive optical power;
a third lens having a negative optical power;
a fourth lens having a positive optical power;
the second group has three lenses, and sequentially comprises the following components along the light propagation direction:
a fifth lens having a negative optical power;
a sixth lens having a negative optical power;
a seventh lens having a positive optical power.
2. The projection lens of claim 1 wherein:
the light incident surface and the light emergent surface of the first lens are convex surfaces;
the light emitting surface of the second lens is a convex surface;
the light emitting surface of the third lens is a concave surface;
the light incident surface and the light emergent surface of the fourth lens are convex surfaces, and the third lens and the fourth lens form a cemented lens;
the light incident surface of the fifth lens is a concave surface;
the light incident surface of the sixth lens is a concave surface;
the light emitting surface of the seventh lens is a convex surface;
wherein the first lens is an aspheric lens.
3. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
20mm<BFL<30mm；
120mm<TD<140mm；
BFL represents the axial distance from the image source surface of the projection lens to the light incident surface of the first lens, and TD represents the axial distance from the light emergent surface of the seventh lens to the projection surface of the projection lens.
4. The projection lens of claim 1, wherein the projection lens satisfies the conditional expression:
0.9<f/(IH/tanθ)< 1.1；
13.5 mm/rad<IH/θ< 15.5 mm/rad；
wherein f represents the effective focal length of the projection lens, theta represents the maximum half field angle of light emitted by the projection lens, and IH represents half of the diagonal of the projection lens on the image source surface.
5. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
BFL/TTL>0.3；
the BFL represents the axial distance from the image source surface of the projection lens to the light incident surface of the first lens, and the TTL represents the optical total length of the projection lens.
6. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
0.35<φ1/φ<1；
0.3<φ2/φ<1；
wherein φ 1 represents the focal power of the first lens, φ 2 represents the focal power of the second lens, and φ represents the focal power of the projection lens.
7. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
-2＜φ5/φ＜-0.2；
-2＜φ6/φ＜-0.2；
0.2<φ7/φ<1；
wherein φ 5 represents the focal power of the fifth lens, φ 6 represents the focal power of the sixth lens, φ 7 represents the focal power of the seventh lens, and φ represents the focal power of the projection lens.
8. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
Nd3>1.8，Vd3<45；
Nd4<1.7，Vd4>50；
-1.5<φ3/φ4<-1；
wherein Nd3 denotes a material refractive index of the third lens, Vd3 denotes a material abbe number of the third lens, Nd4 denotes a material refractive index of the fourth lens, Vd4 denotes a material abbe number of the fourth lens, Φ 3 denotes an optical power of the third lens, and Φ 4 denotes an optical power of the fourth lens.
9. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
-15×10-6/℃<(dn/dt)1+(dn/dt)4 +(dn/dt)6<-2×10-6/℃；
wherein (dn/dt)1 represents a temperature coefficient of refractive index of a material of the first lens, (dn/dt)4 represents a temperature coefficient of refractive index of a material of the fourth lens, and (dn/dt)6 represents a temperature coefficient of refractive index of a material of the sixth lens.
10. The projection lens of claim 2, wherein the projection lens satisfies the conditional expression:
-3.0<R22/f2<-0.1；
wherein R22 represents a radius of curvature of a light exit surface of the second lens, and f2 represents an effective focal length of the second lens.
11. A projection apparatus, characterized in that the projection apparatus comprises an image source and a projection lens according to any one of claims 1 to 10, the image source is used for emitting light, and the projection lens is arranged in the emergent direction of the emitted light of the image source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111558516.4A CN113946028B (en) | 2021-12-20 | 2021-12-20 | Projection lens and projection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111558516.4A CN113946028B (en) | 2021-12-20 | 2021-12-20 | Projection lens and projection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113946028A CN113946028A (en) | 2022-01-18 |
| CN113946028B true CN113946028B (en) | 2022-05-24 |
Family
ID=79339333
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111558516.4A Active CN113946028B (en) | 2021-12-20 | 2021-12-20 | Projection lens and projection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113946028B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115047591B (en) * | 2022-05-30 | 2023-09-05 | 歌尔光学科技有限公司 | Projection lens and projection device |
| TWI819774B (en) * | 2022-09-05 | 2023-10-21 | 揚明光學股份有限公司 | Vehicle projection lens |
| CN115268040B (en) * | 2022-10-08 | 2023-02-10 | 深圳京龙睿信科技有限公司 | Object space telecentric projection lens |
| CN117092800B (en) * | 2023-10-17 | 2024-02-20 | 江西联益光学有限公司 | Zoom lens |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5103342A (en) * | 1989-09-08 | 1992-04-07 | Dainippon Screen Mfg. Co., Ltd. | Apochromatic lens system |
| CN107436484A (en) * | 2017-09-15 | 2017-12-05 | 江西联创电子有限公司 | Projection lens |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103293642B (en) * | 2012-03-02 | 2015-08-26 | 扬明光学股份有限公司 | Projection lens and projection arrangement |
| CN103823289A (en) * | 2012-11-19 | 2014-05-28 | 上海三鑫科技发展有限公司 | Miniature projection lens |
| WO2018173585A1 (en) * | 2017-03-22 | 2018-09-27 | ソニー株式会社 | Projecting lens and projection device |
-
2021
- 2021-12-20 CN CN202111558516.4A patent/CN113946028B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5103342A (en) * | 1989-09-08 | 1992-04-07 | Dainippon Screen Mfg. Co., Ltd. | Apochromatic lens system |
| CN107436484A (en) * | 2017-09-15 | 2017-12-05 | 江西联创电子有限公司 | Projection lens |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113946028A (en) | 2022-01-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113946028B (en) | Projection lens and projection device | |
| WO2019237847A1 (en) | Optical lens system | |
| WO2018042844A1 (en) | Information display device | |
| CN112731630B (en) | Optical imaging lens | |
| JP3588283B2 (en) | Projection lens and projector using it | |
| CN115220199B (en) | Projection lens | |
| US5949589A (en) | Retro-focus type lens | |
| CN115128769B (en) | Optical lens | |
| CN115291371B (en) | Optical lens | |
| CN211698383U (en) | Optical imaging system, image capturing device with optical imaging system and electronic device with optical imaging system | |
| WO2024061220A1 (en) | Optical lens | |
| CN112882209B (en) | Wide-angle lens and imaging apparatus | |
| KR100473243B1 (en) | Projection lens and projector provided with the same | |
| US11966012B2 (en) | Projection lens including four lenses of −+−+ refractive powers | |
| CN116859557B (en) | Projection lens and projection device | |
| JP3040187B2 (en) | Projection lens | |
| CN109975960B (en) | Around wide-angle athermalized lens and automobile panoramic around system | |
| CN115291365A (en) | Optical system with large aperture and vehicle-mounted camera device | |
| CN115657312A (en) | Projection lens and projection system | |
| CN117008284A (en) | Projection lens, projection system and automobile | |
| JPH06208054A (en) | Projection lens system for rear projection system tv | |
| JP2813744B2 (en) | Projection lens | |
| CN220894639U (en) | Projection lens for AR-HUD | |
| CN114721135B (en) | Optical imaging lens | |
| CN115220203B (en) | Optical imaging lens |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |