CN115113373A - Projection lens - Google Patents
Projection lens Download PDFInfo
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- CN115113373A CN115113373A CN202210923296.9A CN202210923296A CN115113373A CN 115113373 A CN115113373 A CN 115113373A CN 202210923296 A CN202210923296 A CN 202210923296A CN 115113373 A CN115113373 A CN 115113373A
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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
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
Abstract
The invention discloses a projection lens, which comprises a front lens group and a rear lens group with positive focal power; the focal length of the projection lens is f, and the focal length is more than 11.5mm and less than f and less than 13.5 mm; and/or the focal length of the front lens group is fA, 30mm < fA <70 mm; the focal length of the rear lens group is fB, and the focal length is more than 10mm and less than fB and less than 40 mm; the rear lens group includes a negative-power cemented triplet. The projection lens has compact structure and small size, and is beneficial to realizing the miniaturization of a projection optical machine.
Description
Technical Field
The invention belongs to the technical field of projection imaging, and particularly relates to a projection lens with a compact structure.
Background
The development of micro-projection technology is faster and faster, and with the increase of the demand of consumers for the viewing effect of micro-projectors, high brightness and high resolution become a great trend of the development of micro-projection. In order to meet the requirements of a high-brightness and high-resolution optical machine, the number of the original pixels of the light-emitting chip is gradually increased, the size of the chip is gradually increased, and correspondingly, the design difficulty of the lens is gradually increased.
For example, a large-size display chip of about 0.47 inches appears in the prior art, and the structure of the existing projection lens is not compact enough, which results in a large optical engine volume when being applied to the large-size display chip. Therefore, when the projection lens is applied to a large-size display chip, how to design a projection lens of a miniaturized projection optical machine for the large-size display chip is a technical problem which needs to be solved urgently.
Disclosure of Invention
The invention aims to provide a projection lens, which solves the technical problem that the existing projection lens is not compact in structure and causes a large projection light machine when being applied to a large-size display chip.
In order to realize the purpose of the invention, the invention is realized by adopting the following technical scheme:
a projection lens includes a front lens group and a rear lens group of positive power;
the focal length of the projection lens is f, and the focal length is 11.5mm < f <13.5 mm; and/or the presence of a gas in the gas,
the focal length of the front lens group is fA, and the focal length is more than 30mm and less than fA and less than 70 mm;
the focal length of the rear lens group is fB, and the focal length of the rear lens group is more than 10mm and less than fB and less than 40 mm;
the rear lens group comprises a negative focal power tri-cemented lens.
In the projection lens, the focal length of the triple cemented lens is f alpha, 140mm < f alpha and 90 mm.
The projection lens as described above, comprising a stop between the front lens group and the rear lens group;
the Air gap between the lens closest to the diaphragm in the front lens group and the diaphragm is Air51, and Air51 is more than or equal to 0.1mm and less than 30 mm;
and an Air gap between the diaphragm and a lens closest to the diaphragm in the rear lens group is Air52, and Air52 is more than or equal to 0.1mm and less than 20 mm.
According to the projection lens, the optical total length of the projection lens is T, half of the diagonal length of the image plane is IH, and T/IH is more than or equal to 15 and less than or equal to 25.
The projection lens as described above, which has one aspherical lens.
In the projection lens, the front lens group includes, in order from the magnification side to the reduction side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens.
In the projection lens, the second lens is an aspheric lens.
In the projection lens described above, the first lens is a glass lens.
In the projection lens, the second lens is a plastic lens.
In the projection lens, the focal powers of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are respectively negative, negative and positive.
In the projection lens assembly, the rear lens group includes, in order from the magnification side to the reduction side, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens.
In the projection lens, the sixth lens element, the seventh lens element and the eighth lens element are cemented into the triple cemented lens element, and the focal powers of the sixth lens element, the seventh lens element and the eighth lens element are negative, positive and negative, respectively.
Compared with the prior art, the invention has the advantages and positive effects that: the projection lens comprises a front lens group and a rear lens group with positive focal power; the focal length of the projection lens is f, and the focal length is 11.5mm < f <13.5 mm; and/or the focal length of the front lens group is fA, and the focal length of the front lens group is more than 30mm and less than 70 mm; the focal length of the rear lens group is fB, and the focal length is more than 10mm and less than fB and less than 40 mm; the rear lens group includes a negative-power cemented triplet. The projection lens has compact structure and small size, and is beneficial to realizing the miniaturization of a projection optical machine.
Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.
Drawings
Fig. 1 is a schematic configuration diagram according to a first embodiment of the present invention.
Fig. 2 is a light path diagram of a first embodiment of the invention.
Fig. 3 is a distortion diagram according to a first embodiment of the present invention.
FIG. 4 is a MTF graph according to a first embodiment of the present invention.
Fig. 5 is a through focus MTF graph according to the first embodiment of the present invention.
Fig. 6 is a dot-column diagram of a first embodiment of the present invention.
Fig. 7 is a vertical axis chromatic aberration diagram according to a first embodiment of the present invention.
Fig. 8 is a schematic configuration diagram according to a second embodiment of the present invention.
Fig. 9 is a light path diagram of a second embodiment of the present invention.
Fig. 10 is a distortion diagram of a second embodiment of the present invention.
FIG. 11 is a MTF graph according to a second embodiment of the present invention.
Fig. 12 is a through focus MTF graph according to the second embodiment of the present invention.
Fig. 13 is a dot diagram of a second embodiment of the present invention.
Fig. 14 is a vertical axis chromatic aberration diagram according to a second embodiment of the present invention.
In the figure, the position of the upper end of the main shaft,
1. a first lens;
2. a second lens;
3. a third lens;
4. a fourth lens;
5. a fifth lens;
6. a sixth lens;
7. a seventh lens;
8. an eighth lens;
9. a ninth lens;
10. a tenth lens;
11. a diaphragm;
12. a galvanometer;
13. a turning prism;
14. an image source.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to the accompanying drawings and the detailed description.
As shown in fig. 1-2, 8-9, the projection device includes an image source 14, a galvanometer 12, a turning prism 13, and a projection lens. The projection lens comprises a front lens group of positive power and a rear lens group with a diaphragm 11 therebetween.
The projected light is emitted from the image source 14, passes through the turning prism 13, the galvanometer 12, the rear lens group (tenth lens 10, ninth lens 9, eighth lens 8, seventh lens 7, sixth lens 6), the diaphragm 11, and the front lens group (fifth lens 5, fourth lens 4, third lens 3, second lens 2, and first lens 1) in order, thereby displaying the projected image.
The image source 14 may be implemented by a Digital Micromirror Device (DMD) chip. The DMD is composed of a plurality of digital micro-mirrors arranged in a matrix, each micro-mirror can deflect and lock towards the positive direction and the negative direction during working, so that light rays are projected according to a set direction and swing at the frequency of tens of thousands of hertz, and light beams from an illumination light source enter a projection lens through the overturning reflection of the micro-mirrors to be imaged on a screen. The DMD has the advantages of high resolution, no need of digital-to-analog conversion of signals and the like. Of course, image source 14 may alternatively be a Liquid Crystal On Silicon (LCOS) chip or other display device that emits light.
The present embodiment performs a lens imaging design for a DMD of about 0.47 inches as a light emitting chip.
The focal power is the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and represents the capability of the optical system to deflect light. The negative focal power lens is a lens with thin middle and thick periphery, is also called as a concave lens and has the function of diverging light; the positive focal power lens is a lens with thick middle part and thin periphery, which is also called a convex lens and has the function of converging light.
The front lens group is positive focal power, is positioned at the front end of the lens and comprises 1 aspheric lens and 4 spherical lenses.
As shown in fig. 1, 2, 8, and 9, the front lens group includes, in order from the magnification side (left side in the drawing) to the reduction side (right side in the drawing), a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 5.
The first lens 1 is a meniscus lens having a negative focal length.
The second lens 2 is a meniscus aspherical lens having a negative focal length.
The third lens 3 is a meniscus lens having a negative focal length.
The fourth lens 4 is a meniscus lens having a negative focal length.
The fifth lens 5 is a biconvex lens having a positive focal length.
Wherein the third lens 3 and the fourth lens 4 can be cemented into a double cemented lens.
The rear lens group is positive focal power, is positioned at the rear end of the lens and comprises 5 spherical lenses.
As shown in fig. 1, 2, 8, and 9, the rear lens group includes, in order from the magnification side (left side in the drawing) to the reduction side (right side in the drawing), a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, and a tenth lens 10.
The sixth lens 6 is a meniscus lens having a negative focal length.
The seventh lens 7 is a biconvex lens having a positive focal length.
The eighth lens 8 is a meniscus lens having a negative focal length.
The ninth lens 9 is a biconvex lens having a positive focal length.
The tenth lens 10 is a meniscus lens having a negative focal length.
The rear lens group includes a negative-power cemented triplet, and specifically, the sixth lens 6, the seventh lens 7, and the eighth lens 8 may be combined together as a cemented triplet.
The diaphragm 11 is located between the fifth lens 5 and the sixth lens 6.
In the embodiment, only 1 aspheric lens is used, so that the tolerance sensitivity of the lens is reduced, and the mass production is facilitated.
The small-size and compact-structure projection light machine is beneficial to realizing the miniaturization of the projection light machine.
The lens of the embodiment can be made of glass materials, and the thermal stability is higher.
The second lens 2 is aspheric, i.e. the second lens 2 is an aspheric lens. Because the first lens 1 is a glass lens, the second lens 2 can be made of a plastic material, that is, the second lens 2 is a plastic lens, which has the following advantages: (1) the cost is reduced; (2) the front and the rear glass lenses are protected, so that scratch can be prevented; (3) close to the front end, the temperature is lower, the thermal deformation is small, and the influence on lens analysis is small.
One side of the first lens 1 facing the direction of the rear lens group is a concave surface, and one side of the first lens 1 facing away from the direction of the rear lens group is a convex surface;
one side of the second lens 2 facing the direction of the rear lens group is a concave surface, and one side of the second lens 2 departing from the direction of the rear lens group is a convex surface;
one side of the third lens 3 facing the rear lens group is a plane (in fig. 1 and 2) or a convex surface (in fig. 8 and 9), and the side facing away from the rear lens group is a concave surface;
one side of the fourth lens 4 facing the direction of the rear lens group is a convex surface, and one side of the fourth lens 4 facing away from the direction of the rear lens group is a concave surface;
one side of the fifth lens 5 facing the direction of the rear lens group is a convex surface, and the other side of the fifth lens 5 facing away from the direction of the rear lens group is a convex surface;
the side of the sixth lens 6 facing the front lens group is a plane (fig. 1 and 2) or a convex surface (fig. 8 and 9), and the side facing away from the front lens group is a concave surface;
one side of the seventh lens 7 facing the direction of the front lens group is a convex surface, and the other side of the seventh lens 7 facing away from the direction of the front lens group is a convex surface;
one side of the eighth lens 8 facing the direction of the front lens group is a concave surface, and one side of the eighth lens 8 facing away from the direction of the front lens group is a convex surface;
one side of the ninth lens 9 facing the direction of the front lens group is a convex surface, and the other side of the ninth lens 9 facing away from the direction of the front lens group is a convex surface;
the tenth lens element 10 has a convex surface on a side facing the front lens group and a concave surface on a side facing away from the front lens group.
For the effective focal length of the projection lens:
the focal length of the projection lens is f, and the focal length is 11.5mm < f <13.5 mm; and/or the presence of a gas in the gas,
the focal length of the front lens group is fA, and the focal length is more than 30mm and less than fA and less than 70 mm;
the focal length of the rear lens group is fB, and 10mm < fB <40 mm.
The focal length of the first lens 1 is f1, -60mm < f1< -40 mm;
the focal length of the second lens 2 is f2, -50mm < f2< -30 mm;
the focal length of the third lens 3 is f3, -20mm < f3< -50 mm;
the focal length of the fourth lens 4 is f4, 40mm < f4<60 mm;
the focal length of the fifth lens 5 is f5, 30mm < f5<50 mm;
the focal length of the sixth lens 6 is f6, -120mm < f6< -80 mm;
the focal length of the seventh lens 7 is f7, -30mm < f7< -10 mm;
the focal length of the eighth lens 8 is f8, 1100mm < f8<1200 mm;
the focal length of the ninth lens 9 is f9, 30mm < f9<50 mm;
the tenth lens 10 has a focal length f10, 50mm < f10<70 mm; and/or the presence of a gas in the gas,
the focal length of the triple cemented lens formed by the sixth lens 6, the seventh lens 7 and the eighth lens 8 is f alpha, which is more than-140 mm and less than-90 mm.
The focal power distribution of the embodiment is uniform, so that the tolerance sensitivity of each lens is lower, the yield of the lens is improved, and the mass production is facilitated.
For the thickness of the projection lens:
the optical total length of the projection lens is T, and T is more than 110mm and less than 130 mm; wherein, the optical total length is the distance from the first lens 1 to the imaging surface.
The middle thicknesses of the lenses of the projection lens are respectively as follows:
the thickness of the lens of the first lens 1 is T1, and T1 is more than 1mm and less than 5 mm;
the thickness of the lens of the second lens 2 is T2, T2 is more than 1mm and less than 10 mm;
the thickness of the lens of the third lens 3 is T3, T3 is more than 1mm and less than 8 mm;
the thickness of the lens of the fourth lens 4 is T4, T4 is more than 1mm and less than 10 mm;
the thickness of the lens of the fifth lens 5 is T5, T5 is more than 1mm and less than 10 mm;
the thickness of the lens of the sixth lens 6 is T6, T6 is more than 0.8mm and less than 5 mm;
the thickness of the middle lens of the seventh lens 7 is T7, T7 is more than 1mm and less than 12 mm;
the thickness of the lens of the eighth lens 8 is T8, T8 is more than 1mm and less than 8 mm;
the thickness of the lens of the ninth lens 9 is T9, T9 is more than 1mm and less than 10 mm;
the thickness of the lens of the tenth lens 10 is T10, T10 is more than 1mm and less than 10 mm;
the thickness of the lens of the galvanometer 12 is T11, and T11 is more than 1mm and less than 4 mm;
the thickness of the lens of the turning prism 13 is T12, 12mm < T12 < 18 mm.
This embodiment has the following advantages for the design of the thickness in the lens: (1) the difficulty of the manufacturing process of the lens is favorably reduced; (2) the raw material is saved, and the cost is reduced; (3) the length of the lens can be reduced, and miniaturization can be realized.
For the air gap of the projection lens:
the Air gap between the first lens 1 and the second lens 2 is Air1, 0.1mm < Air 1< 10 mm;
the Air gap between the second lens 2 and the third lens 3 is Air2, 0.1mm < Air 2< 20 mm;
the Air gap between the third lens 3 and the fourth lens 4 is Air3, and Air3 is more than or equal to 0mm and less than 20 mm;
the Air gap between the fourth lens 4 and the fifth lens 5 is Air4, and Air4 is more than or equal to 0.1mm and less than 15 mm;
the Air gap between the fifth lens 5 and the sixth lens 6 is Air5, and Air5 is more than or equal to 0.1mm and less than 50 mm;
wherein, the Air gap between the fifth lens 5 and the diaphragm lens 11 is Air51, and Air51 is more than or equal to 0.1mm and less than 30 mm; the Air gap between the diaphragm lens 11 and the sixth lens 6 is Air52, and Air52 is more than or equal to 0.1mm and less than 20 mm;
the Air gap between the sixth lens 6 and the seventh lens 7 is Air6, and Air6 is more than or equal to 0mm and less than 5 mm;
the Air gap between the seventh lens 7 and the eighth lens 8 is Air7, and Air7 is more than or equal to 0mm and less than 5 mm;
the Air gap between the eighth lens 8 and the ninth lens 9 is Air8, 0.1mm < Air 8< 10 mm;
the Air gap between the ninth lens 9 and the tenth lens 10 is Air9, 0.1mm < Air 9< 10 mm.
The Air gap between the tenth lens 10 and the galvanometer 12 is Air10, and is more than 0mm and less than Air10 and less than 12 mm;
the Air gap between the galvanometer 12 and the turning prism 13 is Air11, and 0mm < Air11 <12 mm.
The design of the air gap in this embodiment has the following advantages: (1) the lens and the lens cone are matched in structure, assembly is facilitated, and process assembly difficulty is reduced; (2) the Air intervals (namely Air51 and Air52) before and after the diaphragm are restrained according to the method, so that the tolerance sensitivity of lenses before and after the diaphragm is reduced, and the assembly yield of the lens is improved; (3) the method is favorable for reducing the aberration of the outer edge of the shaft of the lens and improving the image quality.
Wherein, the Air space between the turning prism and the rear lens group (namely Air10+ Air11) has the following constraint beneficial effects:
(1) a sufficient assembly gap is reserved between the lens and the lighting main body part, so that the structural design and the process assembly are facilitated, and the mass production is improved; (2) the tolerance sensitivity of the lens is reduced, and the European assembly yield of the lens is improved; (3) the length of the lens can be reduced, and miniaturization can be realized.
The curvature radius of the lens, the focal length of the projection lens is f:
the curvature radius of the first lens 1 is R11 at the side departing from the rear lens group direction, R12 at the side facing the rear lens group direction, 0.3 < R11/f <5, 0.2 < R12/f < 3;
the curvature radius of one side of the second lens 2 departing from the direction of the rear lens group is R21, the curvature radius of one side facing the direction of the rear lens group is R22, R21/f is more than 0.2 and less than 5, and R22/f is more than 0.1 and less than 5;
the curvature radius of the side of the third lens 3 departing from the direction of the rear lens group is R31, the curvature radius of the side facing the direction of the rear lens group is R32, -5 < R31/f < -0.3, 0.1 < R32/f;
the curvature radius of the side of the fourth lens 4 departing from the rear lens group direction is R41, the curvature radius of the side facing the rear lens group direction is R42, -20 < R41/f < -1, -5 < R42/f < -1;
the curvature radius of the side of the fifth lens 5 departing from the rear lens group direction is R51, the curvature radius of the side facing the rear lens group direction is R52, 1< R51/f < 10, -15 < R52/f < -1;
the curvature radius of one side of the sixth lens 6 facing the front lens group direction is R61, the curvature radius of one side deviating from the front lens group direction is R62, 0.1 < R61/f, 0.1 < R62/f < 5;
the curvature radius of one side of the seventh lens 7 facing the front lens group direction is R71, the curvature radius of one side deviating from the front lens group direction is R72, 0.1 < R71/f <5, -5 < R72/f < 0.1;
the curvature radius of the eighth lens 8 on the side facing the front lens group direction is R81, and the curvature radius on the side departing from the front lens group direction is R82, -5 < R81/f < 0.1, -5 < R82/f < 0.1;
the curvature radius of the ninth lens 9 facing the front lens group direction is R91, the curvature radius of the ninth lens 9 facing away from the front lens group direction is R92, 1< R91/f < 10, -5 < R92/f < -0.1;
the tenth lens 10 has a radius of curvature of R101 on the side facing the front lens group direction, a radius of curvature of R102 on the side facing away from the front lens group direction, 0.1 < R101/f <5, and 0.1 < R102/f < 20.
The design of the curvature radius of the present embodiment has the following advantages: (1) the difficulty of the manufacturing process of the lens is favorably reduced; (2) the tolerance sensitivity of the lens is reduced, and the yield of lens assembly is improved; (3) the aberration of the lens can be better corrected, and the imaging definition is improved.
The optical total length of the projection lens is T, half of the length of the diagonal of an image plane is IH, and T/IH is more than or equal to 15 and less than or equal to 25; when the relational expression is satisfied, the lens can have a working distance matched with the display element, and the requirement of miniaturization is satisfied.
The projection lens is suitable for:
the image height is less than or equal to 8.5 mm.
The projection ratio is more than or equal to 0.8, wherein the projection ratio refers to the ratio of the projection distance to the width of the projection picture.
The F-number of the projection lens is more than 1.5, the requirement of the projection lens on the brightness can be met, wherein the aperture ratio is the ratio of the focal length to the aperture diameter, and when the aperture ratio is smaller, the relative aperture of the projection lens is larger, and the light transmission amount is larger; conversely, when the aperture ratio is larger, the relative aperture of the projection lens is smaller, and the amount of light transmitted is smaller.
The field angle FOV of the projection lens is <40 °, wherein the field angle is also called field angle in optical engineering, the size of the field angle determines the field range of the optical instrument, and the field angle can be represented by the FOV.
In the projection lens shown in fig. 1 and 2, the total optical length of the projection lens is 119.5 mm.
The specific parameters of the projection lens are shown in table 1. Including the radius of curvature, thickness, glass material, half-aperture of the lens.
Table 1:
other main parameters of the projection lens of the embodiment are as follows:
the F-number of the projection lens is 1.7; field angle FOV is 32 °; the throw ratio was 1.2.
Based on the parameter data in table 1, fig. 3 is a distortion diagram of a projection lens, where distortion refers to the aberration of different magnifications of different parts of an object when the object is imaged by an optical assembly, and the distortion may cause the similarity of the object image to be deteriorated, but does not affect the definition of the image. As can be seen from fig. 3, the distortion of the projection lens of this embodiment is less than 1%, which satisfies the level of human eye viewing.
Based on the parameter data in table 1, fig. 4 is a Modulation Transfer Function (MTF) diagram of each view field chip surface of the projection lens, where the MTF diagram is used to refer to the relationship between the modulation degree and the logarithm of each millimeter line in the image, and is used to evaluate the detail reduction capability of the scene. And taking the projection angle as a frequency coordinate between sampling of a view field, and taking the ordinate as a transfer function MTF value. As can be seen from fig. 4, in the projection lens of this embodiment, the average MTF of each field is greater than 0.6, and the image formation is good.
Based on the parameter data of table 1, fig. 5 is a through-focus MTF graph of the projection lens, i.e., the variation of MTF value with through-focus distance. As can be seen from FIG. 5, the defocus range with MTF > 0.4 is greater than 0.02mm, has a larger defocus range, is low in risk of hot virtual focus, and can adapt to unstable lighting environments.
Based on the parameter data in table 1, fig. 6 is a dot diagram of a projection lens, all fields of view are less than 1pixel, and the level of human eye viewing can be satisfied.
Based on the parameter data in table 1, fig. 7 is a vertical axis chromatic aberration diagram of the projection lens, where the vertical axis chromatic aberration is less than 1.6 μm, and a lower imaging smear degree can be achieved.
In the projection lens shown in fig. 8 and 9, the total optical length of the projection lens is 115 mm.
The specific parameters of the projection lens are shown in table 2. Including the radius of curvature, thickness, glass material, half-aperture of the lens.
Table 2:
other main parameters of the projection lens of the embodiment are as follows:
the F-number of the projection lens is 1.75; field angle FOV is 31.7 °; the throw ratio was 1.2.
Based on the parameter data in table 2, fig. 10 is a distortion diagram of the projection lens, where distortion refers to the aberration of different magnifications of different parts of the object when the object is imaged by the optical components, and the distortion may cause the similarity of the object image to be deteriorated, but does not affect the definition of the image. As can be seen from fig. 10, the distortion of the projection lens of this embodiment is less than 1%, which satisfies the level of human eye observation.
Based on the parameter data in table 2, fig. 11 is a Modulation Transfer Function (MTF) diagram of each view field chip surface of the projection lens, where the MTF diagram is used to refer to a relationship between a modulation degree and a logarithm of each millimeter line in an image and is used to evaluate detail reduction capability of a scene. And taking the projection angle as a frequency coordinate between sampling of a view field, and taking the ordinate as a transfer function MTF value. As can be seen from fig. 11, in the projection lens of this embodiment, the average MTF of each field is > 0.6, and the image formation is good.
Based on the parameter data in table 1, fig. 12 is a through-focus MTF graph of the projection lens, that is, the variation of MTF value with through-focus distance. As can be seen from fig. 12, the defocus range with MTF > 0.4 is greater than 0.02mm, has a large defocus range, is low in risk of hot virtual focus, and is adaptable to an unstable lighting environment.
Based on the parameter data in table 1, fig. 13 is a dot diagram of a projection lens, all fields of view are less than 1pixel, and the level of human eye viewing can be satisfied.
Based on the parameter data in table 1, fig. 14 is a vertical axis chromatic aberration diagram of the projection lens, where the vertical axis chromatic aberration is less than 1.6 μm, and a lower imaging smear level can be achieved.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (12)
1. A projection lens, comprising a front lens group and a rear lens group of positive power;
the focal length of the projection lens is f, and the focal length is 11.5mm < f <13.5 mm; and/or the presence of a gas in the gas,
the focal length of the front lens group is fA, and the focal length is more than 30mm and less than fA and less than 70 mm;
the focal length of the rear lens group is fB, and the focal length of the rear lens group is more than 10mm and less than fB and less than 40 mm;
the rear lens group comprises a negative focal power tri-cemented lens.
2. The projection lens of claim 1,
the focal length of the tri-cemented lens is f alpha, -140mm < f alpha < -90 mm.
3. The projection lens of claim 1 wherein the projection lens comprises a stop between the front lens group and the rear lens group;
the Air gap between the lens closest to the diaphragm in the front lens group and the diaphragm is Air51, and Air51 is more than or equal to 0.1mm and less than 30 mm;
and an Air gap between the diaphragm and a lens closest to the diaphragm in the rear lens group is Air52, and Air52 is more than or equal to 0.1mm and less than 20 mm.
4. The projection lens of claim 1, wherein the projection lens has an optical total length of T, and wherein IH is half of the diagonal length of the image plane, and 15 ≦ T/IH ≦ 25.
5. The projection lens of claim 1 wherein the projection lens has an aspheric lens.
6. The projection lens of claim 5 wherein the front lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens in order from the magnification side to the reduction side.
7. The projection lens of claim 6 wherein the second lens is an aspheric lens.
8. The projection lens of claim 7 wherein the first lens is a glass lens.
9. The projection lens of claim 8 wherein the second lens is a plastic lens.
10. The projection lens of claim 6, wherein the optical powers of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are respectively negative, negative and positive.
11. The projection lens of claim 1 wherein the rear lens group comprises a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens in sequence from the magnification side to the reduction side.
12. The projection lens of claim 11, wherein the sixth lens, the seventh lens and the eighth lens are cemented into the triple cemented lens, and optical powers of the sixth lens, the seventh lens and the eighth lens are negative, positive and negative respectively.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210923296.9A CN115113373A (en) | 2022-08-02 | 2022-08-02 | Projection lens |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210923296.9A CN115113373A (en) | 2022-08-02 | 2022-08-02 | Projection lens |
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| Publication Number | Publication Date |
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| CN115113373A true CN115113373A (en) | 2022-09-27 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210923296.9A Pending CN115113373A (en) | 2022-08-02 | 2022-08-02 | Projection lens |
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| CN (1) | CN115113373A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117008299A (en) * | 2023-10-07 | 2023-11-07 | 福建福特科光电股份有限公司 | Large-aperture low-distortion fixed-focus line scanning lens |
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2022
- 2022-08-02 CN CN202210923296.9A patent/CN115113373A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117008299A (en) * | 2023-10-07 | 2023-11-07 | 福建福特科光电股份有限公司 | Large-aperture low-distortion fixed-focus line scanning lens |
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