CN117572597A - Projection lens and projection device - Google Patents

Projection lens and projection device Download PDF

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Publication number
CN117572597A
CN117572597A CN202311518404.5A CN202311518404A CN117572597A CN 117572597 A CN117572597 A CN 117572597A CN 202311518404 A CN202311518404 A CN 202311518404A CN 117572597 A CN117572597 A CN 117572597A
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China
Prior art keywords
lens
projection
group
lens group
projection lens
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CN202311518404.5A
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Chinese (zh)
Inventor
姜滨
王中亮
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Goertek Optical Technology Co Ltd
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Goertek Optical Technology Co Ltd
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Priority to CN202311518404.5A priority Critical patent/CN117572597A/en
Publication of CN117572597A publication Critical patent/CN117572597A/en
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
    • G—PHYSICS
    • 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

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

Abstract

The embodiment of the application provides a projection lens and projection equipment. The projection lens sequentially comprises from an enlargement side to a reduction side: a first lens group having negative optical power, a second lens group having positive optical power, a stop, a third lens group having negative optical power, and a fourth lens group having positive optical power; the projection lens only comprises an aspheric lens, the aspheric lens is positioned in the first lens group, and the materials of the lenses contained in the projection lens are all glass materials.

Description

Projection lens and projection device
Technical Field
The embodiment of the application relates to the technical field of optical imaging, in particular to a projection lens and projection equipment.
Background
With the continuous development of markets and technologies, laser projectors with higher brightness and wider color gamut gradually enter the home.
One of the image source chips carried in the existing household laser projector is a 0.47' DMD, and the lens used in the existing household laser projector is an ultra-short-focus projection lens which is high in cost. The quantity of specially developed long-focus laser projection lenses is less, and the problems of larger chromatic aberration, poorer resolving power, sensitive tolerance, higher cost and the like exist.
In view of this, it is necessary to propose a completely new optical solution for the laser projection lens of a 0.47 "dmd.
Disclosure of Invention
The purpose of the application is to provide a projection lens and a novel technical scheme of projection equipment.
The embodiment of the application provides a projection lens. The projection lens sequentially comprises from an enlargement side to a reduction side: a first lens group having negative optical power, a second lens group having positive optical power, a stop, a third lens group having negative optical power, and a fourth lens group having positive optical power;
the projection lens only comprises an aspheric lens, the aspheric lens is positioned in the first lens group, and the materials of the lenses contained in the projection lens are all glass materials.
Optionally, the effective focal length of the first lens group is F1, the effective focal length of the projection lens is EFL, and the projection lens satisfies: 1.2< |F1/EFL| <1.6;
the effective focal length of the second lens group is F2, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 1.8< |F2/EFL| <2.4;
the focal length of the third lens group is F3, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 4.2< |F3/EFL| <4.8;
the focal length of the fourth lens group is F4, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 1.6< |F4/EFL| <2.0.
Optionally, the aperture value FNO of the projection lens is less than or equal to 2.4, and the diameter D of the imaging circle is more than or equal to 16mm.
Optionally, from a magnification side to a reduction side, the first lens group includes a first lens and a second lens, the second lens being the aspherical lens;
the optical power of the first lens and the second lens are negative.
Optionally, the optical abbe number of the second lens is greater than 60.
Optionally, from the magnification side to the reduction side, the second lens group includes a third lens and a fourth lens, and optical powers of the third lens and the fourth lens are positive.
Optionally, from a magnification side to a reduction side, the third lens group includes a first cemented lens and a second cemented lens, wherein an optical power of at least one of the first cemented lens and the second cemented lens is positive.
Optionally, from the enlargement side to the reduction side, the first cemented lens includes a fifth lens and a sixth lens, and the second cemented lens includes a seventh lens and an eighth lens.
Optionally, at least two lenses of the third lens group have an optical abbe number greater than 60.
Optionally, the fourth lens group includes a ninth lens and a tenth lens from the enlargement side to the reduction side, and optical powers of the ninth lens and the tenth lens are positive.
Optionally, the tenth lens has an optical abbe number of less than 25.
Optionally, the center thickness range of the first lens is: 3 mm-3.5 mm;
the center thickness range of the second lens is as follows: 1.5 mm-2 mm;
the center thickness range of the third lens is as follows: 4 mm-4.5 mm;
the center thickness range of the fourth lens is as follows: 4.1 mm-4.7 mm;
the center thickness range of the fifth lens is as follows: 3.3 mm-3.8 mm;
the center thickness range of the sixth lens is: 1.2 mm-1.6 mm;
the center thickness range of the seventh lens is: 4.5 mm-5 mm;
the center thickness range of the eighth lens is: 5 mm-5.5 mm;
the center thickness range of the ninth lens is: 4 mm-4.5 mm;
the center thickness range of the tenth lens is: 3 mm-3.5 mm.
Optionally, the projection device comprises a projection lens as described in the first aspect.
According to the embodiment of the application, the projection lens is provided, all the lenses in the projection lens are made of glass materials, only one aspheric lens is contained in the first lens group, and the lens has the characteristics of small chromatic aberration, small distortion, high resolving power, stable temperature performance, low cost and the like through reasonable focal power distribution and lens material collocation, so that the market demand is met.
Other features of the present specification and its advantages will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and together with the description, serve to explain the principles of the specification.
Fig. 1 is a schematic structural diagram of a projection lens according to an embodiment of the present application.
Fig. 2 is an MTF graph of the projection lens shown in fig. 1.
Fig. 3 is a schematic view of a spot array of the projection lens shown in fig. 1.
Fig. 4 is a field curvature distortion diagram of the projection lens shown in fig. 1.
Fig. 5 is a vertical axis color difference diagram of the projection lens shown in fig. 1.
Fig. 6 is a second schematic structural diagram of a projection lens according to an embodiment of the present disclosure.
Fig. 7 is an MTF graph of the projection lens shown in fig. 6.
Fig. 8 is a schematic view of a spot array of the projection lens shown in fig. 6.
Fig. 9 is a field curvature distortion diagram of the projection lens shown in fig. 6.
Fig. 10 is a vertical axis color difference diagram of the projection lens shown in fig. 6.
Fig. 11 is a third schematic structural diagram of a projection lens according to an embodiment of the present disclosure.
Fig. 12 is an MTF graph of the projection lens shown in fig. 11.
Fig. 13 is a schematic view of a spot array of the projection lens shown in fig. 11.
Fig. 14 is a field curvature distortion diagram of the projection lens shown in fig. 11.
Fig. 15 is a vertical axis color difference diagram of the projection lens shown in fig. 11.
Reference numerals illustrate:
100. a first lens group; 200. a second lens group; 300. a third lens group; 400. a fourth lens group;
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 dithering device; 13. a spectroscopic device; 14. and a display chip.
Detailed Description
Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses.
Techniques and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
The embodiment of the application provides a projection lens. Referring to fig. 1, 6 and 11, the projection lens includes, in order from an enlargement side to a reduction side: the first lens group 100 having negative optical power, the second lens group 200 having positive optical power, the stop 11, the third lens group 300 having negative optical power, and the fourth lens group 400 having positive optical power.
The projection lens only comprises an aspheric lens, the aspheric lens is located in the first lens group 100, and the lens contained in the projection lens is made of glass.
In the embodiment of the present application, the projection lens includes, in order from an enlargement side to a reduction side: the first lens group 100, the second lens group 200, the diaphragm 11, the third lens group 300, the fourth lens group 400, the dithering device 12, the light splitting device 13, and the display chip 14, wherein a protective glass may be further disposed between the light splitting device 13 and the display chip 14.
Wherein the display chip 14 may be a digital micromirror element (Digital Micro mirror Device, DMD) chip. The DMD consists of a plurality of digital micro-reflectors arranged in a matrix, and each micro-reflector can deflect and lock in the forward and reverse directions when in operation, so that light rays are projected in a given direction and swing at a frequency of tens of thousands of hertz, and the light rays from the illumination light source enter an optical system to be imaged on a screen through the turning reflection of the micro-reflectors. The DMD has the advantages of high resolution, no need of digital-to-analog conversion of signals and the like. This embodiment uses a 0.47 inch DMD chip. Of course, the display chip 14 may be a liquid crystal on silicon (Liquid Crystal On Silicon, LCOS) chip or other display device for emitting light, which is not limited in this application.
Dithering device 12 may improve the resolution of the projection system during operation; the light splitting means 13 are TIR or RTIR prisms in the projection lens, which are equal in optical path. A stop 11 is provided between the second lens group 200 and the third lens group 300 to control a lens clear aperture. Where the diaphragm 11 is set up to control the overall volume of the projection lens.
Wherein the optical power of the first lens group 100 is negative, and an aspherical lens is included in the first lens group 100, the first lens group 100 is used for deflecting light rays with a large angle of view, and correcting optical distortion by using the aspherical lens.
Wherein the optical power of the second lens group 200 is positive, the second lens group 200 is used to compensate for curvature of field, astigmatism and spherical aberration.
Wherein the optical power of the third lens group 300 is negative, the third lens group 300 can effectively improve the chromatic aberration of the lens and reduce the tolerance sensitivity.
The fourth lens group 400 may be used to collect light and reduce the light exit angle, wherein the optical power of the fourth lens group 400 is positive.
Therefore, in the embodiment of the application, all the lenses in the projection lens are made of glass materials, and only one aspheric lens is contained in the first lens group 100, so that the lens has the characteristics of small chromatic aberration, small distortion, high resolving power, stable temperature performance, low cost and the like through reasonable focal power distribution and lens material collocation, and meets the market demand.
In one embodiment, the focal length of the first lens group 100 is F1, the effective focal length of the projection lens is EFL, and the projection lens satisfies: 1.2< |F1/EFL| <1.6;
the focal length of the second lens group 200 is F2, the effective focal length of the projection lens is EFL, and the projection lens satisfies: 1.8< |F2/EFL| <2.4.
The focal length of the third lens group 300 is F3, the effective focal length of the projection lens is EFL, and the projection lens satisfies: 4.2< |F3/EFL| <4.8.
The focal length of the fourth lens group 400 is F4, the effective focal length of the projection lens is EFL, and the projection lens satisfies: 1.6< |F4/EFL| <2.0.
In this embodiment, the lens groups of the four group structures are set with respective corresponding focal ranges reasonably, and the focal ranges of the lens groups and the projection lenses meet a certain ratio and are adjustable. By combining and collocating the group focal length ranges of the four groups of structures, the tolerance sensitivity among the groups of the projection lens is reduced, and the projection lens further has high resolution.
In one embodiment, the aperture value FNO.ltoreq.2.4, the imaging circle diameter D.ltoreq.16 mm. Specifically, the proper aperture value FNO and imaging circle diameter enable the lens to perfectly match the DMD of 0.47 inch, so that the light flux, the resolution and the cost of the projection lens are optimally balanced.
In one embodiment, referring to fig. 1, 6 and 11, from an enlargement side to a reduction side, the first lens group 100 includes a first lens 1 and a second lens 2, the second lens 2 being the aspherical lens; the optical powers of the first lens 1 and the second lens 2 are negative.
In this embodiment, the first lens group 100 includes two lenses having negative optical power, and the first lens group 100 is used to deflect light rays of a large angle field of view while correcting optical distortion with an aspherical lens.
Specifically, the first lens group 100 includes a first lens 1 and a second lens 2. The first lens 1 is a meniscus type spherical glass lens with negative focal power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface. The first lens 1 can rapidly deflect light using a meniscus negative lens. The second lens 2 is an aspheric lens with negative focal power, the object side surface is S3, the image side surface is S4, and the aspheric lens can effectively correct optical distortion and reduce the caliber of the front end of the lens. In addition, the second lens 2 is made of glass, so that the back focus offset caused by temperature can be effectively improved, and the temperature stability is improved.
The first lens group may include not only two lenses having negative optical power, but also three or four lenses having negative optical power, wherein, in the first lens group, the lens farthest from the magnification side is an aspherical lens. Or the first lens group may further include a lens having positive optical power, for example, a lens having positive optical power is located between two lenses having negative optical power, wherein in the first lens group, the lens farthest from the magnification side is an aspherical lens.
In one embodiment, the optical abbe number of the second lens 2 is greater than 60.
In this embodiment, the second lens 2 is made of a lens material having an optical abbe number Vd >60, which is advantageous in reducing chromatic aberration.
In one embodiment, referring to fig. 1, 6 and 11, from the enlargement side to the reduction side, the second lens group 200 includes a third lens 3 and a fourth lens 4, and the optical powers of the third lens 3 and the fourth lens 4 are positive.
In this embodiment, the second lens group 200 includes the third lens 3 and the fourth lens 4. The third lens 3 is a spherical lens having positive optical power, and has an object side surface S5 and an image side surface S6. The fourth lens element 4 has a positive refractive power, and has an object-side surface S7 and an image-side surface S8. The second lens group 200 may compensate for the astigmatic aberration introduced by the first lens group 100 and introduce a compensating spherical aberration.
It should be noted that, the second lens group includes not only two lenses with positive focal power, but also three or four lenses with positive focal power; or the second lens group may also comprise a lens with negative optical power, for example a lens with negative optical power is located between two lenses with positive optical power.
In one embodiment, referring to fig. 1, 6 and 11, the third lens group 300 includes, from a magnification side to a reduction side, a first cemented lens and a second cemented lens, wherein an optical power of at least one group of the first cemented lens and the second cemented lens is positive.
In the embodiment, the projection lens provided by the embodiment of the application adopts the spherical lens, the aspherical lens and the cemented lens which are matched with each other for use, so that the lens image quality is effectively improved, the tolerance sensitivity is reduced, and the manufacturing yield is improved on the premise of meeting the requirement of optical performance.
In the first and second cemented lenses, at least one group of cemented lenses has positive focal power, so that the tolerance sensitivity of the cemented lenses can be effectively reduced and the production yield can be improved by the focal power distribution of the first and second cemented lenses.
In one embodiment, referring to fig. 1, 6 and 11, the first cemented lens includes a fifth lens 5 and a sixth lens 6, and the second cemented lens includes a seventh lens 7 and an eighth lens 8 from the enlargement side to the reduction side.
In this embodiment, the third lens group 300 includes a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8. The fifth lens element 5 with an object-side surface S9 and an image-side surface S10 is a spherical lens; the sixth lens element 6 with an object-side surface S10 and an image-side surface S11 is a spherical lens; the fifth lens 5 and the sixth lens 6 form a first group cemented lens L1 on the S10 plane. The seventh lens 7 is a spherical lens, the object side surface is S12, and the image side surface is S13; the eighth lens element 8 with an object-side surface of S13 and an image-side surface of S14 is a spherical lens; the seventh lens 7 and the eighth lens 8 form a second group cemented lens L2 on the S13 plane.
In one embodiment, at least two lenses of the third lens group 300 have an optical abbe number greater than 60.
In this embodiment, at least two of the first and second cemented lens groups have optical abbe numbers >60, which can effectively improve the axial chromatic aberration and the vertical chromatic aberration of the projection lens and correct the residual spherical aberration partially introduced by the second lens group 200.
In one embodiment, referring to fig. 1, 6 and 10, from the enlargement side to the reduction side, the fourth lens group 400 includes a ninth lens 9 and a tenth lens 10, and the optical powers of the ninth lens 9 and the tenth lens 10 are positive.
In this embodiment, the fourth lens group 400 includes a ninth lens 9 and a tenth lens 10. The ninth lens 9 is a spherical lens having positive optical power, and has an object side surface S15 and an image side surface S16. The tenth lens 10 is a spherical lens having positive optical power, and has an object side surface S17 and an image side surface S18. The fourth lens group 400 can convert and converge light, reduce the angle of outgoing light of the lens, improve telecentricity, and correct residual spherical aberration, coma and astigmatic aberration.
It should be noted that, the second lens group includes not only two lenses with positive focal power, but also three or four lenses with positive focal power; or the second lens group may also comprise a lens with negative optical power, for example a lens with negative optical power is located between two lenses with positive optical power.
In one embodiment, the tenth lens 10 has an optical abbe number of less than 25.
In this embodiment, the tenth lens element 10 of the fourth lens group 400 has an optical abbe number smaller than 25, which can effectively compensate for residual chromatic aberration.
In this embodiment, the fourth lens group 400 includes two lenses, and the tenth lens 10 is the lens farthest from the first lens group 100, so that the optical abbe number of less than 25 is limited to the tenth lens 10 material to effectively compensate for the residual chromatic aberration. When the fourth lens group 400 includes more than two lenses, an optical abbe number of a lens of the fourth lens group 400 farthest from the first lens group 100 is defined to be less than 25 to effectively compensate for residual chromatic aberration.
In one embodiment, referring to fig. 1, 6 and 11, the central thickness range of the first lens 1 is: 3 mm-3.5 mm; the center thickness range of the second lens 2 is: 1.5 mm-2 mm; the center thickness range of the third lens 3 is as follows: 4 mm-4.5 mm; the center thickness range of the fourth lens 4 is: 4.1 mm-4.7 mm; the center thickness range of the fifth lens 5 is: 3.3 mm-3.8 mm; the center thickness range of the sixth lens 6 is: 1.2 mm-1.6 mm; the center thickness range of the seventh lens 7 is: 4.5 mm-5 mm; the center thickness range of the eighth lens 8 is: 5 mm-5.5 mm; the center thickness range of the ninth lens is: 4 mm-4.5 mm; the center thickness range of the tenth lens is: 3 mm-3.5 mm. For example, the center thickness 3.2905mm of the first lens 1, the center thickness 1.999mm of the second lens 2, the center thickness 4.0448mm of the third lens 3, the center thickness 4.6980mm of the fourth lens 4, the center thickness 3.5844mm of the fifth lens 5, the center thickness 1.5000mm of the sixth lens 6, the center thickness 4.9569mm of the seventh lens 7, the center thickness 5.3535mm of the eighth lens 8, the center thickness 4.3415mm of the ninth lens 9 and the center thickness 3.4434mm of the tenth lens 10, in this embodiment, the average transmittance of the lens at the center of the optical axis in the wavelength band of 450nm to 650nm is >85% by optimizing the material and center thicknesses of all lenses of the lens.
In a specific embodiment, the projection lens includes, in order from a magnification side to a reduction side, a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400, the first lens group 100 including a first lens 1 and a second lens 2, the optical powers of the first lens 1 and the second lens 2 being negative, and the second lens 2 being an aspherical lens; the second lens group 200 includes a third lens 3 and a fourth lens 4, and the optical powers of the third lens 3 and the fourth lens 4 are positive; the third lens group 300 includes two groups of cemented lenses, the first cemented lens including a fifth lens 5 and a sixth lens 6, the second cemented lens including a seventh lens 7 and an eighth lens 8; the fourth lens group 400 includes a ninth lens 9 and a tenth lens 10, and the optical powers of the ninth lens 9 and the tenth lens 10 are positive. In this embodiment, the lenses except the second lens 2 are spherical lenses. In this embodiment, all of the lenses are made of glass. Therefore, in the embodiment of the application, through the optimal design, under the condition that only one glass aspheric lens and 10 lenses of two groups of double-cemented lenses are adopted, through reasonable focal power distribution and material collocation, indexes such as MTF, chromatic aberration and distortion of the lens are improved, the product cost is reduced, and the lens is more suitable for a laser projection market.
The embodiment of the application also provides projection equipment, which comprises the projection lens. The projection device may be a projector, for example a laser projector.
The optical module provided in the embodiments of the present application is described below by three embodiments.
Example 1
The embodiment of the application provides a projection lens. Referring to fig. 1, the projection lens includes, in order from an enlargement side to a reduction side: a first lens group 100, a second lens group 200, a stop 11, a third lens group 300, a fourth lens group 400, a dithering device 12, a beam splitting device 13, and a display chip 14.
The first lens group 100 includes, in order from the enlargement side to the reduction side, a first lens 1 and a second lens 2, a surface S1 of the first lens 1 away from the second lens 2 is convex, and a surface S2 of the first lens 1 close to the second lens 2 is concave. The surface S3 of the second lens 2 close to the first lens 1 is convex, and the surface S4 of the second lens 2 far from the first lens 1 is concave.
The second lens group 200 includes, in order from the magnification side to the reduction side, a third lens 3 and a fourth lens 4, a surface S5 of the third lens 3, which is far from the fourth lens 4, is concave, and a surface S6 of the third lens 3, which is near the fourth lens 4, is convex. The surface S7 of the fourth lens 4 close to the third lens 3 is convex, and the surface S8 of the fourth lens 4 far from the third lens 3 is concave.
The third lens group 300 includes, in order from the magnification side to the reduction side, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8, the fifth lens 5 and the sixth lens 6 being cemented together, the seventh lens 7 and the eighth lens 8 being cemented together.
The surface S9 of the fifth lens 5 away from the sixth lens 6 is a plane, and the surface S10 of the fifth lens 5 close to the sixth lens 6 is a concave surface; the surface S10 of the sixth lens 6, which is close to the fifth lens 5, is convex, and the surface S11 of the sixth lens 6, which is far from the fifth lens 5, is convex.
The surface S12 of the seventh lens 7, which is far from the eighth lens 8, is concave, and the surface S13 of the seventh lens 7, which is near to the eighth lens 8, is concave; the surface S13 of the eighth lens 8 close to the seventh lens 7 is convex, and the surface S14 of the eighth lens 8 distant from the seventh lens 7 is convex.
The fourth lens group 400 includes, in order from the enlargement side to the reduction side, a ninth lens 9 and a tenth lens 10, a surface S15 of the ninth lens 9 away from the tenth lens 10 being convex, a surface S16 of the ninth lens 9 close to the tenth lens 10 being convex, a surface S17 of the tenth lens 10 close to the ninth lens 9 being convex, a surface S18 of the tenth lens 10 away from the ninth lens 9 being convex.
Wherein the second lens 2 is a glass aspheric lens, and the rest lenses are glass spherical lenses.
Thus, this example 1 provides a lens that employs an optical power of "negative - Positive direction - Negative pole - Positive "four-group architecture projection lens. The lens comprises 10 lenses, and the focal power, the shape of the object side surface and the image side surface of the lenses and the aspheric lens are reasonably arranged
The number of the surface lenses and the spherical lenses can stabilize the light trend of the whole optical system of the projection lens, so that the projection lens realizes high resolution, and simultaneously realizes small volume and low cost.
Wherein the relevant parameters of each device in example 1 of the present application are shown in table 1:
table 1:
the second lens 2 has an even aspherical surface shape satisfying the following formula:
Z＝cy 2 /{1+[1-(1+k)c 2 y 2 ] 1/2 }+a 1 y 2 +a 2 y 4 +a 3 y 6 +a 4 y 8 +a 5 y 10 +a 6 y 12 +a 7 y 14 +a 8 y 16
wherein, the parameter c is the curvature corresponding to the radius, y is the radial coordinate (the unit is the same as the unit of the lens length), and k is the conic coefficient. When k is smaller than-1, the surface profile curve is a hyperbola; when k is equal to-1, the surface profile curve is parabolic; when k is between-1 and 0, the surface profile is elliptical; when k is equal to 0, the surface shape is circular; when k is greater than 0, the surface shape is an oblate curve. a1 to a8 respectively represent coefficients corresponding to the respective radial coordinates, and the shape and size of the aspherical surface of the lens imaging optical surface can be precisely set by the above parameters. Wherein the aspherical coefficients of the second lens 2 are shown in table 2:
table 2:
wherein in this example 1, the main parameters are as shown in table 3: where F1 is the focal length of the first lens group 100, F2 is the focal length of the second lens group 200, and EFL is the effective focal length of the projection lens. L1 is a first cemented lens formed by the fifth lens 5 and the sixth lens 6 cemented together, and L2 is a second cemented lens formed by the seventh lens 7 and the eighth lens 8 cemented together.
Table 3:
the pixel size of the pixel source adopted in embodiment 1 of the present application is 5.4x5.4um, and the corresponding design resolution is 93lp/mm.
As can be seen from FIG. 2, the projection lens of this embodiment 1 has a high resolution with an MTF > 0.6 at 93lp/mm.
Fig. 3 is a dot column diagram with an RMS radius of 3.7um, within 0.8 pixels, ensuring resolution sharpness.
The optical distortion in the field curvature distortion of fig. 4 is less than or equal to 0.6%, so that the size of the distortion generated by the imaging picture is extremely small and is difficult to identify by naked eyes.
The maximum vertical chromatic aberration of the image is less than 0.8um, and within 0.2 pixels, the vertical chromatic aberration is well corrected, so that the image has no color edge phenomenon.
Embodiment 1 of the present application is applicable to a laser projector with a 0.47"DMD (0.47 inch DMD) as the display chip 14, a lens throw ratio of 1.2, and an aperture f No. of 2.4.
Example 2
The embodiment of the application provides a projection lens. Referring to fig. 6, the projection lens includes, in order from an enlargement side to a reduction side: a first lens group 100, a second lens group 200, a stop 11, a third lens group 300, a fourth lens group 400, a dithering device 12, a light splitting device 13, a protective glass, and a display chip 14.
The first lens group 100 includes, in order from the enlargement side to the reduction side, a first lens 1 and a second lens 2, a surface S1 of the first lens 1 away from the second lens 2 is convex, and a surface S2 of the first lens 1 close to the second lens 2 is concave. The surface S3 of the second lens 2 close to the first lens 1 is convex, and the surface S4 of the second lens 2 far from the first lens 1 is concave.
The second lens group 200 includes, in order from the magnification side to the reduction side, a third lens 3 and a fourth lens 4, a surface S5 of the third lens 3, which is far from the fourth lens 4, is concave, and a surface S6 of the third lens 3, which is near the fourth lens 4, is convex. The surface S7 of the fourth lens 4 close to the third lens 3 is convex, and the surface S8 of the fourth lens 4 far from the third lens 3 is concave.
The third lens group 300 includes, in order from the magnification side to the reduction side, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8, the fifth lens 5 and the sixth lens 6 being cemented together, the seventh lens 7 and the eighth lens 8 being cemented together.
The surface S9 of the fifth lens 5 away from the sixth lens 6 is convex, and the surface S10 of the fifth lens 5 close to the sixth lens 6 is convex; the surface S10 of the sixth lens 6 close to the fifth lens 5 is concave, and the surface S11 of the sixth lens 6 far from the fifth lens 5 is concave.
The surface S12 of the seventh lens 7, which is far from the eighth lens 8, is a plane, and the surface S13 of the seventh lens 7, which is near to the eighth lens 8, is a concave surface; the surface S13 of the eighth lens 8 close to the seventh lens 7 is convex, and the surface S14 of the eighth lens 8 distant from the seventh lens 7 is convex.
The fourth lens group 400 includes, in order from the enlargement side to the reduction side, a ninth lens 9 and a tenth lens 10, a surface S15 of the ninth lens 9 away from the tenth lens 10 being convex, a surface S16 of the ninth lens 9 close to the tenth lens 10 being convex, a surface S17 of the tenth lens 10 close to the ninth lens 9 being convex, a surface S18 of the tenth lens 10 away from the ninth lens 9 being convex.
Wherein the device-related parameters of example 2 of the present application are shown in table 4:
table 4:
wherein in this embodiment 2, the surfaces of the remaining lenses are spherical lenses except for the surface of the second lens 2 which is aspherical. The second lens 2 has an even aspherical surface shape satisfying the following formula:
Z＝cy 2 /{1+[1-(1+k)c 2 y 2 ] 1/2 }+a 1 y 2 +a 2 y 4 +a 3 y 6 +a 4 y 8 +a 5 y 10 +a 6 y 12 +a 7 y 14 +a 8 y 16
wherein, the parameter c is the curvature corresponding to the radius, y is the radial coordinate (the unit is the same as the unit of the lens length), and k is the conic coefficient. When k is smaller than-1, the surface profile curve is a hyperbola; when k is equal to-1, the surface profile curve is parabolic; when k is between-1 and 0, the surface profile is elliptical; when k is equal to 0, the surface shape is circular; when k is greater than 0, the surface shape is an oblate curve. a1 to a8 respectively represent coefficients corresponding to the respective radial coordinates, and the shape and size of the aspherical surface of the lens imaging optical surface can be precisely set by the above parameters. Wherein the aspherical coefficients of the second lens 2 are shown in table 5:
table 5:
wherein in this example 2, the main parameters are as shown in table 6: where F1 is the focal length of the first lens group 100, F2 is the focal length of the second lens group 200, and EFL is the effective focal length of the projection lens. L1 is a first cemented lens formed by the fifth lens 5 and the sixth lens 6 cemented together, and L2 is a second cemented lens formed by the seventh lens 7 and the eighth lens 8 cemented together.
Table 6:
the pixel size of the image source adopted in embodiment 2 of the application is 5.4um, and the corresponding design resolution is 93lp/mm.
As can be seen from FIG. 7, the whole view field of the lens of the embodiment 2 has MTF larger than 0.6 at 93lp/mm, and has high resolving power.
Fig. 8 is a dot column diagram with an RMS radius of 4.1um, within 0.8 pixels, ensuring resolution sharpness.
The optical distortion in the field curvature distortion of fig. 9 is less than or equal to 0.6%, so that the size of the distortion generated by the imaging picture is extremely small and is difficult to identify by naked eyes.
The maximum vertical chromatic aberration of the image is less than 0.8um, and within 0.2 pixels, the vertical chromatic aberration is well corrected, and the image is ensured to have no chromatic edge phenomenon.
Embodiment 2 of the present application is applicable to a laser projector with a 0.47"DMD (0.47 inch DMD) as the display chip 14, a lens throw ratio of 1.2, and an aperture f No. of 2.4.
Example 3
The embodiment of the application provides a projection lens. Referring to fig. 11, the projection lens includes, in order from an enlargement side to a reduction side: a first lens group 100, a second lens group 200, a stop 11, a third lens group 300, a fourth lens group 400, a dithering device 12, a light splitting device 13, a protective glass, and a display chip 14.
The first lens group 100 includes, in order from the enlargement side to the reduction side, a first lens 1 and a second lens 2, a surface S1 of the first lens 1 away from the second lens 2 is convex, and a surface S2 of the first lens 1 close to the second lens 2 is concave. The surface S3 of the second lens 2 close to the first lens 1 is convex, and the surface S4 of the second lens 2 far from the first lens 1 is concave.
The second lens group 200 includes, in order from the magnification side to the reduction side, a third lens 3 and a fourth lens 4, a surface S5 of the third lens 3, which is far from the fourth lens 4, is concave, and a surface S6 of the third lens 3, which is near the fourth lens 4, is convex. The surface S7 of the fourth lens 4 close to the third lens 3 is convex, and the surface S8 of the fourth lens 4 far from the third lens 3 is concave.
The third lens group 300 includes, in order from the magnification side to the reduction side, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8, the fifth lens 5 and the sixth lens 6 being cemented together, the seventh lens 7 and the eighth lens 8 being cemented together.
The surface S9 of the fifth lens 5 away from the sixth lens 6 is convex, and the surface S10 of the fifth lens 5 close to the sixth lens 6 is convex; the surface S10 of the sixth lens 6 close to the fifth lens 5 is concave, and the surface S11 of the sixth lens 6 far from the fifth lens 5 is concave.
The surface S12 of the seventh lens 7, which is far from the eighth lens 8, is a plane, and the surface S13 of the seventh lens 7, which is near to the eighth lens 8, is a convex surface; the surface S13 of the eighth lens 8 close to the seventh lens 7 is concave, and the surface S14 of the eighth lens 8 distant from the seventh lens 7 is convex.
The fourth lens group 400 includes, in order from the enlargement side to the reduction side, a ninth lens 9 and a tenth lens 10, a surface S15 of the ninth lens 9 away from the tenth lens 10 being a plane, a surface S16 of the ninth lens 9 close to the tenth lens 10 being a convex surface, a surface S17 of the tenth lens 10 close to the ninth lens 9 being a convex surface, a surface S18 of the tenth lens 10 away from the ninth lens 9 being a plane.
Wherein the respective device-related parameters of example 3 of the present application are shown in table 7:
table 7:
wherein in this embodiment 3, the surfaces of the remaining lenses are spherical lenses except for the surface of the second lens 2 which is aspherical. The second lens 2 has an even aspherical surface shape satisfying the following formula:
Z＝cy 2 /{1+[1-(1+k)c 2 y 2 ] 1/2 }+a 1 y 2 +a 2 y 4 +a 3 y 6 +a 4 y 8 +a 5 y 10 +a 6 y 12 +a 7 y 14 +a 8 y 16
wherein, the parameter c is the curvature corresponding to the radius, y is the radial coordinate (the unit is the same as the unit of the lens length), and k is the conic coefficient. When k is smaller than-1, the surface profile curve is a hyperbola; when k is equal to-1, the surface profile curve is parabolic; when k is between-1 and 0, the surface profile is elliptical; when k is equal to 0, the surface shape is circular; when k is greater than 0, the surface shape is an oblate curve. a1 to a8 respectively represent coefficients corresponding to the respective radial coordinates, and the shape and size of the aspherical surface of the lens imaging optical surface can be precisely set by the above parameters. Wherein the aspherical coefficients of the second lens 2 are shown in table 8:
table 8:
wherein in this example 3, the main parameters are as shown in table 9: where F1 is the focal length of the first lens group 100, F2 is the focal length of the second lens group 200, and EFL is the effective focal length of the projection lens. L1 is a first cemented lens formed by the fifth lens 5 and the sixth lens 6 cemented together, and L2 is a second cemented lens formed by the seventh lens 7 and the eighth lens 8 cemented together.
Table 9:
the pixel size of the image source adopted in embodiment 3 of the application is 5.4um, and the corresponding design resolution is 93lp/mm.
It can be seen from 12 that the whole view field of the lens of the embodiment 3 has MTF more than 0.6 at 93lp/mm, and has high resolving power.
Fig. 13 is a dot column diagram with an RMS radius of 3.7um, within 1 pixel, ensuring sharp resolution.
The optical distortion in the field curvature distortion of fig. 14 is less than or equal to 0.6%, so that the size of the distortion generated by the imaging picture is extremely small and is difficult to identify by naked eyes.
The maximum vertical chromatic aberration of FIG. 15 is 1um, and within 0.2 pixel, the vertical chromatic aberration is well corrected, and the image is ensured to have no color edge phenomenon.
Embodiment 3 of the present application is applicable to a laser projector with a 0.47"DMD (0.47 inch DMD) as the display chip 14, a lens throw ratio of 1.3, and an aperture f No. of 2.4.
The foregoing embodiments mainly describe differences between the embodiments, and as long as there is no contradiction between different optimization features of the embodiments, the embodiments may be combined to form a better embodiment, and in consideration of brevity of line text, no further description is given here.
Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims (13)

1. A projection lens, characterized in that the projection lens comprises, in order from an enlargement side to a reduction side: a first lens group (100) having negative optical power, a second lens group (200) having positive optical power, a stop, a third lens group (300) having negative optical power, and a fourth lens group (400) having positive optical power;
the projection lens only comprises an aspheric lens, the aspheric lens is positioned in the first lens group (100), and the materials of the lenses contained in the projection lens are all glass materials.
2. The projection lens of claim 1 wherein the lens is configured to,
the focal length of the first lens group (100) is F1, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 1.2< |F1/EFL| <1.6;
the focal length of the second lens group (200) is F2, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 1.8< |F2/EFL| <2.4;
the focal length of the third lens group (300) is F3, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 4.2< |F3/EFL| <4.8;
the focal length of the fourth lens group (400) is F4, the effective focal length of the projection lens is EFL, and the projection lens meets the following conditions: 1.6< |F4/EFL| <2.0.
3. The projection lens of claim 1, wherein the aperture value FN of the projection lens is equal to or less than 2.4, and the imaging circle diameter D is equal to or more than 16mm.
4. A projection lens according to any of claims 1-3, characterized in that the first lens group (100) comprises, from an enlargement side to a reduction side, a first lens (1) and a second lens (2), the second lens (2) being the aspherical lens; the optical power of the first lens (1) and the second lens (2) are negative.
5. Projection lens according to claim 4, characterized in that the optical abbe number of the second lens (2) is larger than 60.
6. The projection lens according to claim 4, characterized in that the second lens group (200) comprises, from the enlargement side to the reduction side, a third lens (3) and a fourth lens (4), the optical powers of both the third lens (3) and the fourth lens (4) being positive.
7. The projection lens according to claim 6, wherein the third lens group (300) includes, from a magnification side to a reduction side, a first cemented lens and a second cemented lens, wherein an optical power of at least one group of the first cemented lens and the second cemented lens is positive.
8. Projection lens according to claim 7, characterized in that the first cemented lens comprises, from the magnification side to the reduction side, a fifth lens (5) and a sixth lens (6), and the second cemented lens comprises a seventh lens (7) and an eighth lens (8).
9. Projection lens according to claim 7 or 8, characterized in that at least two of said third lens groups (300) have an optical abbe number greater than 60.
10. The projection lens according to claim 8, characterized in that the fourth lens group (400) includes, from an enlargement side to a reduction side, a ninth lens (9) and a tenth lens (10), the optical powers of both the ninth lens (9) and the tenth lens (10) being positive.
11. Projection lens according to claim 10, characterized in that the optical abbe number of the tenth lens (10) is smaller than 25.
12. The projection lens of claim 10 wherein the lens is configured to,
the center thickness range of the first lens is as follows: 3 mm-3.5 mm;
the center thickness range of the second lens is as follows: 1.5 mm-2 mm;
the center thickness range of the third lens is as follows: 4 mm-4.5 mm;
the center thickness range of the fourth lens is as follows: 4.1 mm-4.7 mm;
the center thickness range of the fifth lens is as follows: 3.3 mm-3.8 mm;
the center thickness range of the sixth lens is: 1.2 mm-1.6 mm;
the center thickness range of the seventh lens is: 4.5 mm-5 mm;
the center thickness range of the eighth lens is: 5 mm-5.5 mm;
the center thickness range of the ninth lens is: 4 mm-4.5 mm;
the center thickness range of the tenth lens is: 3 mm-3.5 mm.
13. A projection device, characterized in that the projection device comprises a projection lens according to any of claims 1-12.
CN202311518404.5A 2023-11-14 2023-11-14 Projection lens and projection device Pending CN117572597A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311518404.5A CN117572597A (en) 2023-11-14 2023-11-14 Projection lens and projection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311518404.5A CN117572597A (en) 2023-11-14 2023-11-14 Projection lens and projection device

Publications (1)

Publication Number Publication Date
CN117572597A true CN117572597A (en) 2024-02-20

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