CN115657312A - Projection lens and projection system - Google Patents
Projection lens and projection system Download PDFInfo
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- CN115657312A CN115657312A CN202211379549.7A CN202211379549A CN115657312A CN 115657312 A CN115657312 A CN 115657312A CN 202211379549 A CN202211379549 A CN 202211379549A CN 115657312 A CN115657312 A CN 115657312A
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Abstract
The invention discloses a projection lens and a projection system, wherein the projection lens comprises: a first lens group; the second lens group is positioned on the light-emitting side of the first lens group and comprises a double-cemented lens group; the third lens group is positioned on one side of the second lens group far away from the first lens group; the fourth lens group is positioned on one side of the third lens group, which is far away from the second lens group; the sum of the number of the lenses in the first lens group, the second lens group, the third lens group and the fourth lens group is seven. The sum of the number of the lenses in the projection lens is seven, the projection lens only comprises one double-cemented lens group, the complexity of the projection lens is greatly reduced, the volume of the projection lens is reduced, and the projection lens is suitable for HUD products.
Description
Technical Field
The invention relates to the technical field of projection display, in particular to a projection lens and a projection system.
Background
Head Up Display (HUD for short), also called as automobile Head-Up Display, refers to a technology of projecting important driving information such as speed per hour, navigation and the like onto a windshield in front of a driver by using an optical reflection principle, so that the driver can obtain driving information without looking away from the front as much as possible, and the technology plays a good auxiliary role in driving safety.
In a DLP-based projection system, light emitted from a Light source is modulated and then irradiated onto a Digital Micro Device (DMD), reflected by a Micro mirror unit on the DMD and then irradiated onto a projection lens, and projected onto a projection screen through the projection lens to form an image.
However, because the HUD has a small space, the conventional projection lens generally has a large volume, a complicated optical path structure and a large number of lenses, and the conventional projection lens is difficult to match with the HUD.
Disclosure of Invention
The invention provides a projection lens, which is used for reducing the number of lenses in the projection lens, reducing the volume of the projection lens and simplifying the light path structure.
A first aspect of the present invention provides a projection lens, including: a first lens group;
the second lens group is positioned on the light-emitting side of the first lens group, and the second lens group comprises a double-cemented lens group;
the third lens group is positioned on one side of the second lens group far away from the first lens group;
the fourth lens group is positioned on one side of the third lens group far away from the second lens group;
the sum of the number of lenses in the first lens group, the second lens group, the third lens group and the fourth lens group is seven.
In some embodiments of the invention, the first lens group comprises a first lens which is a biconvex spherical positive lens.
In some embodiments of the present invention, the second lens group includes a second lens, a third lens and a fourth lens, and the third lens and the fourth lens are cemented to form the double cemented lens group.
In some embodiments of the present invention, the second lens is a biconvex spherical positive lens, the third lens is a biconvex spherical positive lens, and the fourth lens is a biconcave spherical negative lens.
In some embodiments of the present invention, a refractive index of the third lens is smaller than a refractive index of the fourth lens, and an abbe number of the third lens is larger than an abbe number of the fourth lens.
In some embodiments of the invention, the third lens group comprises a fifth lens and a sixth lens; the fifth lens is a concave-convex spherical negative lens, and the sixth lens is a biconvex spherical positive lens.
In some embodiments of the invention, the fourth lens group comprises a seventh lens, and the seventh lens is a negative meniscus lens.
In some embodiments of the present invention, the equivalent focal length of the projection lens, the focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group, and the focal length of the fourth lens group satisfy the following relationships:
1<|F1/F0|<2；
1<|F2/F0|<1.5；
2.5<|F3/F0|<3.5；
2.5<|F4/F0|<3；
wherein F0 represents an equivalent focal length of the projection lens, F1 represents a focal length of the first lens group, F2 represents a focal length of the second lens group, F3 represents a focal length of the third lens group, and F4 represents a focal length of the fourth lens group.
In some embodiments of the present invention, a lens throw ratio of the projection lens is 1.0 to 2.0;
the total length of the projection lens, the length of the first lens group, the length of the second lens group, the length of the third lens group and the length of the fourth lens group satisfy the following relations:
0.01<|L1/L0|<0.06；
0.1<|L2/L0|<0.5；
0.1<|L3/L0|<0.5；
0.01<|L4/L0|<0.05；
the rear working distance of the projection lens meets the following relation:
0.15<|BFL/L0|<0.5；
wherein L0 represents the total length of the projection lens, L1 represents the length of the first lens group, L2 represents the length of the second lens group, L3 represents the length of the third lens group, L4 represents the length of the fourth lens group, and BFL represents the rear working distance of the projection lens.
Another aspect of the invention provides a projection system comprising: a projection light source, a light modulation member, a projection screen, and any of the projection lenses described above;
the projection light source is used for emitting projection light;
the light modulation component is positioned on the light emergent side of the projection light source and is used for modulating incident light;
the projection lens is positioned on the light emitting side of the light modulation component and used for imaging emergent light of the light modulation component;
and the projection screen is positioned on the light-emitting side of the projection lens.
The invention has the following beneficial effects:
the invention provides a projection lens, comprising: a first lens group; the second lens group is positioned on the light-emitting side of the first lens group and comprises a double-cemented lens group; the third lens group is positioned on one side of the second lens group far away from the first lens group; the fourth lens group is positioned on one side of the third lens group far away from the second lens group; the sum of the number of the lenses in the first lens group, the second lens group, the third lens group and the fourth lens group is seven. The sum of the number of the lenses in the projection lens is seven, and only one double-cemented lens group is included, so that the complexity of the projection lens is greatly reduced, the volume of the projection lens is reduced, and the HUD projection lens is suitable for HUD products.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a projection system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a projection lens according to an embodiment of the present invention;
FIG. 3 is a ray trace diagram provided by an embodiment of the present invention;
fig. 4 is a schematic view of a simulation of a light fan shape of a projection lens according to an embodiment of the invention;
fig. 5 is a second schematic view illustrating a light fan simulation of a projection lens according to an embodiment of the invention;
fig. 6 is a third schematic view illustrating a simulation of a light fan shape of a projection lens according to an embodiment of the invention;
fig. 7 is a schematic diagram illustrating a simulation of a curvature of field of a projection lens according to an embodiment of the invention;
fig. 8 is a schematic diagram illustrating simulation of a distortion curve of a projection lens according to an embodiment of the present invention;
fig. 9 is a schematic diagram illustrating a simulation of light spot distribution of a projection lens according to an embodiment of the present invention;
fig. 10 is a schematic diagram illustrating a simulation of relative illumination of a projection lens according to an embodiment of the invention;
fig. 11 is a schematic diagram illustrating a simulation of a modulation transfer function curve of a projection lens according to an embodiment of the present invention.
The projection system comprises a projection lens 100, a projection light source 200, a projection screen 300, a light modulation component 1, a glass cover plate 2, a total reflection prism 3, a first lens 4, a second lens 5, a third lens 6, a fourth lens 7, a fifth lens 8, a sixth lens 9, a seventh lens 10, a first lens group 101, a second lens group 102, a third lens group 103, a fourth lens group 104 and an S-aperture diaphragm.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is further described with reference to the accompanying drawings and examples. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus, a repetitive description thereof will be omitted. The words indicating positions and directions in the present invention are illustrated by way of example in the accompanying drawings, but may be changed as required and are within the scope of the present invention. The drawings of the present invention are for illustrative purposes only and do not represent true scale.
The conventional HUD mainly includes an image Generation Unit (PGU) for generating an output image of the HUD and an optical display system for displaying the image, wherein the image formed by the image Generation Unit is magnified and zoomed out by a series of optical means and then imaged at a set position in front of the driver's sight line.
The HUD is essentially an optical projection system in which the core PGU consists of a light source, illumination optics, optics and other optical components, so that the PGU is the largest factor that determines the volume of the entire HUD. Most of projection lens structures in the related art are divided into three lens groups, and the number of used lenses is large, so that the volume of the projection lens is large, the optical structure is complex, however, due to the characteristic that the HUD is small in using space, the existing projection lens is difficult to match with the size of the HUD.
In view of this, the embodiment of the present invention provides a small fixed-focus projection lens suitable for use in a HUD and a projection system including the projection lens, and the small fixed-focus projection lens provided in the embodiment of the present invention can reduce the number of lenses in the projection lens on the premise of not affecting the use effect, thereby effectively reducing the volume of a PGU and simplifying the optical path structure.
Fig. 1 is a schematic structural diagram of a projection system according to an embodiment of the present invention.
As shown in fig. 1, a projection system provided in an embodiment of the present invention includes: a projection lens 100, a projection light source 200, a light modulation part 1, and a projection screen 300. Wherein, projection light source 200 can be used for the outgoing projection light, and light modulation part 1 is located projection light source 200's light-emitting side, can be used for modulating incident light, and projection lens 100 is located light-emitting side of light modulation part 1, can be used for imaging to light modulation part 1's emergent light, and projection screen 300 is located projection lens 100's light-emitting side, and the image that projection lens 100 formed can be thrown to projection screen 300.
The HUD in the embodiments of the present invention may employ a DLP-based projection system. Specifically, the projection Light source 200 may be a Light Emitting Diode (LED) Light source, a laser Light source, or the like, and the projection Light source 200 may be a monochromatic Light source or a multicolor Light source. When the projection light source 200 is an LED light source, it can be formed by combining a plurality of red, green and blue LED lamps. When the projection light source 200 is a laser light source, a plurality of lasers emitting laser light of different colors may be combined, or a single-color laser may be used. Because the system that red, green, blue trichromatic laser ware constitutes is too bulky, in order to save the cost, can adopt monochromatic laser ware such as blue laser ware, still need set up the colour wheel in projection system this moment and realize full-color projection, the colour wheel can be used for converting the monochromatic laser of incidenting into the laser outgoing of other colours.
The light modulation element 1 may be a DMD chip, which consists of thousands of micromirrors, each micromirror being a precise, micro-mirror capable of controlling one pixel of the projection plane. Each micromirror in the DMD chip may be tilted to an on or off state, each micromirror may be driven by a rotating device below the micromirror under the control of a digital driving signal, and the angle and direction of each micromirror may be adjusted at a fast speed, so that light incident on the surface of the micromirror in the on state may be reflected to the projection lens and finally imaged on the projection screen 300.
Because the HUD uses the characteristic of the scene, can also include such as the optical component of refractor, speculum etc. in PGU's the illumination light path, this kind of optical component can set up in the income light side of DMD chip, reflect the light of projection light source outgoing through speculum etc. that sets up reasonable quantity and position, can shorten the length of light path, can not set up the projection screen in the HUD product, light directly falls to form a virtual image in the windshield the place ahead of car, be convenient for the driver to observe, the embodiment of the invention mainly provides a projection lens that is favorable to reducing PGU size, do not limit to other optical element in PGU's the illumination light path here.
In specific implementation, the projection system may further include a glass cover 2 and a Total Internal Reflection (TIR) prism 3. The glass cover plate 2 is located on the light-emitting side of the DMD chip, and is usually a component in a finished DMD chip product, which can protect the surface of the DMD chip, the TIR prism 3 is located on one side of the glass cover plate 2 close to the projection lens 100, and light reflected from the DMD chip in the illumination light path can enter the projection lens 100 through the transmission of the TIR prism 3.
Fig. 2 is a schematic structural diagram of a projection lens according to an embodiment of the present invention; FIG. 3 is a ray tracing diagram according to an embodiment of the present invention.
As shown in fig. 2, a projection lens provided in an embodiment of the present invention includes: a first lens group 101, a second lens group 102, a third lens group 103, and a fourth lens group 104.
The side where the first lens group 101 is located is a light incident side, the second lens group 102 is located on a light emitting side of the first lens group 101, the third lens group 103 is located on a side of the second lens group 102 away from the first lens group 101, and the fourth lens group 104 is located on a side of the third lens group 103 away from the second lens group 102. In some embodiments of the present invention, an aperture stop S may be further disposed between the second lens group 102 and the third lens group 103, and the aperture stop S may be used to limit the range of light incident from the second lens group 102 to the third lens group 103.
The first lens group 101, the second lens group 102, the third lens group 103, and the fourth lens group 104 are coaxially disposed, and centers of all lenses included in each lens group are located on a main optical axis. Referring to fig. 3, light rays incident from the illumination light path enter the TIR prism through the glass cover plate after being reflected by the DMD chip, enter the first lens group 101 and the second lens group 102 after exiting from the TIR prism, enter the third lens group 103 and the fourth lens group 104 after passing through the aperture stop S, and then enter the subsequent optical system.
In specific implementation, the first lens group 101 and the fourth lens group 104 can be fixedly arranged, and the positions of the second lens group 102 and the third lens group 103 can be finely adjusted, so that better imaging quality can be obtained for different HUD products, the imaging size can be changed within a certain range in the adjustment process for a certain specific HUD product, and the positions of the second lens group 102 and the third lens group 103 are fixed after the imaging size and the imaging quality are adjusted.
Specifically, the first lens group 101 includes a first lens 4, and the first lens 4 is a biconvex spherical positive lens.
The second lens group 102 includes a second lens 5, a third lens 6 and a fourth lens 7 which are gradually arranged away from the first lens group 101, wherein the second lens 5 is a biconvex spherical positive lens, the third lens 6 is a biconvex spherical positive lens, the fourth lens 7 is a biconcave spherical negative lens, and the third lens 6 and the fourth lens 7 are cemented to form a double cemented lens group. The refractive index of the third lens 6 in the double-cemented lens group is smaller than that of the fourth lens 7, and the abbe number of the third lens 6 is larger than that of the fourth lens 7. The double-cemented lens group is arranged in the projection lens, so that the performance of the lens can be optimized, the reflection loss on the lens can be reduced, and meanwhile, chromatic aberration can be corrected.
The third lens group 103 includes a fifth lens 8 and a sixth lens 9 disposed gradually away from the second lens group 102, where the fifth lens 8 is a concave-convex spherical negative lens and the sixth lens 9 is a double-convex spherical positive lens. The third lens group 103 can be used to improve various kinds of aberrations.
The fourth lens group 104 includes a seventh lens 10, and the seventh lens 10 is a negative meniscus lens.
The sum of the number of lenses in the first lens group 101, the second lens group 102, the third lens group 103 and the fourth lens group 104 is seven, wherein only the second lens group 102 includes one double cemented lens group, and compared with a projection lens in the related art, the projection lens provided by the embodiment of the invention has fewer lenses, thereby greatly reducing the complexity of a light path structure in the projection lens. In addition, all lenses in the projection lens are spherical lenses without aspheric lenses, and only one double cemented lens is included, so that the processing difficulty is greatly reduced, and the production cost is saved.
The surface type parameters of each optical component and the distance between each optical component in the projection lens provided by the embodiment of the invention are shown as the following table:
in the embodiment of the present invention, the equivalent focal length of the projection lens, the focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group, and the focal length of the fourth lens group satisfy the following relationships:
1<|F1/F0|<2；
1<|F2/F0|<1.5；
2.5<|F3/F0|<3.5；
2.5<|F4/F0|<3；
wherein, F0 represents the equivalent focal length of the projection lens, F1 represents the focal length of the first lens group, F2 represents the focal length of the second lens group, F3 represents the focal length of the third lens group, F4 represents the focal length of the fourth lens group, and the symbols of the equivalent focal length F0 of the projection lens, the focal length F1 of the first lens group, the focal length F2 of the second lens group, the focal length F3 of the third lens group and the focal length F4 of the fourth lens group are: positive, negative.
In the embodiment of the present invention, the total length of the projection lens, the length of the first lens group, the length of the second lens group, the length of the third lens group, and the length of the fourth lens group satisfy the following relationships:
0.01<|L1/L0|<0.06；
0.1<|L2/L0|<0.5；
0.1<|L3/L0|<0.5；
0.01<|L4/L0|<0.05；
wherein L0 denotes a total length of the projection lens, L1 denotes a length of the first lens group, L2 denotes a length of the second lens group, L3 denotes a length of the third lens group, and L4 denotes a length of the fourth lens group.
The rear working distance of the projection lens satisfies the following relation:
0.15<|BFL/L0|<0.5；
BFL represents the rear working distance of the projection lens, i.e. the distance between the DMD chip and the first lens.
According to the data, the embodiment of the invention carries out reasonable optical design on the surface type of each optical component in the projection lens by changing the parameters such as the thickness, the size, the distance, the radius and the like of each internal optical component in the projection lens, can reduce the number of lenses in the projection lens on the premise of not influencing the use effect of the projection lens, shortens the length of the projection lens to be within 5cm, and simultaneously compresses the cross sectional area of the whole PGU to be within the range of 7cm multiplied by 7cm, thereby effectively reducing the volume of the projection system, enabling the projection system to be matched with the size of the HUD, and being applicable to HUD products.
In the embodiment of the invention, the projection ratio of the projection lens can reach 1.0-2.0, so that the distance between the projection lens and the projection screen can reach a smaller value, and the image display with larger size can be realized in a shorter projection distance. When the projection lens provided by the embodiment of the invention is applied to a HUD product, when the projection picture is 2.53 inches, the resolution of the projection picture can reach 66lp/mm, and the maximum resolution capable of supporting the projection picture can reach 72pl/mm.
The embodiment of the invention simulates the projection lens and provides an image quality evaluation chart of the projection lens.
Fig. 4 is a schematic view of a simulation of a light fan shape of a projection lens according to an embodiment of the invention; fig. 5 is a second schematic view illustrating a light fan simulation of a projection lens according to an embodiment of the invention; fig. 6 is a third schematic view illustrating a simulation of a light fan shape of a projection lens according to an embodiment of the invention.
Figures 4, 5 and 6 show the aberrations between light of three wavelengths, 0.465, 0.525 and 0.647 um, and light of a dominant wavelength at normalized minimum, central and maximum fields of view conditions, respectively.
As shown in fig. 4, 5 and 6, each field of view includes two ray fan simulation diagrams, which can respectively represent ray aberrations of the projection lens in the tangential and sagittal directions, and the abscissa of each curve represents the normalized entrance pupil coordinate Px or Py; the ordinate represents the difference of the respective wavelength light rays at the image plane with respect to the principal ray coordinate, i.e. the lateral aberration, where e x 、e y The x-and y-components of the lateral aberrations between the respective wavelength rays and the principal ray, respectively, and the maximum scale in fig. 4, 5 and 6 is ± 20 μm.
As can be seen from fig. 4, fig. 5 and fig. 6, the coincidence degree of the curves with different wavelengths in each field is high, and the maximum value of the curve on the vertical axis is also within an acceptable range.
Fig. 7 is a simulation diagram of a curvature of field of a projection lens according to an embodiment of the disclosure.
Fig. 7 shows field curves in the meridional and sagittal directions when the projection lens provided by the embodiment of the invention images light rays with three wavelengths of 0.465 μm, 0.525 μm and 0.647 μm respectively. The field curvature curve may represent the distance from the image plane to the paraxial focal plane, where meridional field curvature data is the distance from the image plane to the paraxial focal plane measured along the z-axis on the meridional (YZ plane), sagittal field curvature data is the distance measured on a plane perpendicular to the meridional plane (XZ plane), and the top of the curve represents the maximum field of view. In fig. 7, the horizontal axis represents the magnitude of distortion in mm, the vertical axis represents the field of view in the Y direction, and the field curvature curve is normalized by the maximum radial field of view, and therefore, no unit is provided on the vertical axis.
According to a simulation result, the maximum field of view in the embodiment of the invention is 48.0mm, the maximum meridional field curvature of the projection lens provided by the embodiment of the invention is 0.0559mm, and the maximum sagittal field curvature is 0.0596 mm.
Fig. 8 is a schematic diagram illustrating simulation of a distortion curve of a projection lens according to an embodiment of the present invention.
Fig. 8 shows distortion curves of the projection lens provided by the embodiment of the invention when the projection lens images light with three wavelengths of 0.465 μm, 0.525 μm and 0.647 μm respectively. In fig. 8, the horizontal axis represents the distortion percentage, and the vertical axis represents the size of the field of view.
According to the simulation result, the maximum field of view is 48.0mm, the maximum distortion of the projection lens provided by the embodiment of the invention is ± 1.2825%, and the distortion in the HUD is usually better at ± 3%, so that the projection lens provided by the embodiment of the invention also has better distortion performance.
Fig. 9 is a schematic diagram illustrating a simulation of a light spot distribution of a projection lens according to an embodiment of the present invention.
Fig. 9 shows the spot distribution of the projection lens provided by the embodiment of the present invention for imaging the light with the wavelengths of 0.465 μm, 0.525 μm, and 0.647 μm, respectively, and it can be seen that the aberrations of the projection lens provided by the embodiment of the present invention, such as astigmatism, coma, and chromatic dispersion, are not obvious.
The embodiment of the invention simulates 12 fields of view, and the simulation data is shown in the following table:
the embodiment of the invention can adopt a 0.23' DMD chip, the caliber of the DMD chip is about 7.4 μm, and the root-mean-square radius and the geometric radius of the imaging light spot have smaller values and are smaller than the caliber of the DMD chip, so that the imaging quality is better.
Fig. 10 is a schematic diagram illustrating a simulation of relative illuminance of a projection lens according to an embodiment of the present invention.
Fig. 10 shows relative illuminance as a function of radial field-of-view coordinate Y when the projection lens provided by the embodiment of the present invention images a light ray with a wavelength of 0.525 μm, that is, illuminance on a micro area on an image plane normalized according to the illuminance of zero field of view, where the abscissa represents the field-of-view coordinate in the Y direction, the unit is mm, and the ordinate represents the relative illuminance. As can be seen from fig. 10, the relative illuminance is always kept in the range of 1 or close to 1, and the imaging quality of the projection lens is better.
Fig. 11 is a simulation diagram of a modulation transfer function curve of a projection lens according to an embodiment of the present invention.
Fig. 11 shows graphs of modulation transfer functions, i.e., MTF graphs of light rays with wavelengths of 0.465 μm to 0.647 μm when the projection lens provided by the embodiment of the present invention respectively forms images in the meridional and sagittal directions, where the abscissa represents spatial frequency, and the ordinate represents optical transfer function OTF, and the logarithm of lines per millimeter of image space is used for representing spatial frequency. As can be seen from fig. 11, the ordinate value is close to 1 and the curve is relatively flat, which indicates that the imaging difference between the edge and the center of the projection lens is small and the imaging quality is relatively good.
According to the first invention concept, the projection lens is formed by seven lenses, the number of the used lenses is small, and the complexity of the light path structure in the projection lens is greatly reduced.
According to the second inventive concept, all lenses in the projection lens are spherical lenses, have no aspheric lens, and only comprise one double cemented lens, so that the processing difficulty is greatly reduced, and the production cost is saved.
According to the third inventive concept, parameters such as the thickness, size, distance and radius of each optical component inside the projection lens are changed, the surface type of each optical component in the projection lens is reasonably designed, the length of the projection lens can be shortened on the premise that the using effect of the projection lens is not affected, the size of the projection system is reduced, the projection system can be matched with the size of the HUD, and the HUD is suitable for HUD products.
According to the fourth inventive concept, the projection ratio of the projection lens can reach 1.0-2.0, the distance between the projection lens and the projection screen can reach a smaller value, and a larger-size image can be displayed within a shorter projection distance, and meanwhile, the resolution is better.
According to the fifth inventive concept, the third lens group is arranged in the projection lens to improve aberration, the projection lens is subjected to optical simulation, and according to various image quality evaluation graphs, the conclusion that various aberrations of the projection lens are within an acceptable range and the projection lens has good imaging quality can be obtained.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A projection lens, comprising:
a first lens group;
the second lens group is positioned on the light-emitting side of the first lens group, and the second lens group comprises a double-cemented lens group;
the third lens group is positioned on one side of the second lens group far away from the first lens group;
the fourth lens group is positioned on one side of the third lens group far away from the second lens group;
the sum of the number of lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group is seven.
2. The projection lens of claim 1 wherein the first lens group comprises a first lens that is a biconvex spherical positive lens.
3. The projection lens of claim 1 wherein the second lens group comprises a second lens, a third lens and a fourth lens, and the third lens and the fourth lens are cemented to form the double cemented lens group.
4. The projection lens of claim 3 wherein the second lens is a biconvex spherical positive lens, the third lens is a biconvex spherical positive lens, and the fourth lens is a biconcave spherical negative lens.
5. The projection lens of claim 4, wherein the refractive index of the third lens is smaller than that of the fourth lens, and the abbe number of the third lens is larger than that of the fourth lens.
6. The projection lens of claim 1 wherein the third lens group comprises a fifth lens and a sixth lens; the fifth lens is a concave-convex spherical negative lens, and the sixth lens is a biconvex spherical positive lens.
7. The projection lens of claim 1 wherein the fourth lens group comprises a seventh lens, and the seventh lens is a negative meniscus lens.
8. The projection lens of any of claims 1-7 wherein the equivalent focal length of the projection lens, the focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group, and the focal length of the fourth lens group satisfy the following relationship:
1<|F1/F0|<2；
1<|F2/F0|<1.5；
2.5<|F3/F0|<3.5；
2.5<|F4/F0|<3；
wherein F0 represents an equivalent focal length of the projection lens, F1 represents a focal length of the first lens group, F2 represents a focal length of the second lens group, F3 represents a focal length of the third lens group, and F4 represents a focal length of the fourth lens group.
9. The projection lens of any of claims 1-7 wherein the lens throw ratio of the projection lens is 1.0 to 2.0;
the total length of the projection lens, the length of the first lens group, the length of the second lens group, the length of the third lens group and the length of the fourth lens group satisfy the following relations:
0.01<|L1/L0|<0.06；
0.1<|L2/L0|<0.5；
0.1<|L3/L0|<0.5；
0.01<|L4/L0|<0.05；
the rear working distance of the projection lens meets the following relation:
0.15<|BFL/L0|<0.5；
wherein L0 represents the total length of the projection lens, L1 represents the length of the first lens group, L2 represents the length of the second lens group, L3 represents the length of the third lens group, L4 represents the length of the fourth lens group, and BFL represents the rear working distance of the projection lens.
10. A projection system, comprising: a projection light source, a light modulation element, a projection screen, and a projection lens according to any one of claims 1 to 9;
the projection light source is used for emitting projection light;
the light modulation component is positioned on the light emitting side of the projection light source and is used for modulating incident light;
the projection lens is positioned on the light emitting side of the light modulation component and used for imaging emergent light of the light modulation component;
and the projection screen is positioned on the light-emitting side of the projection lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211379549.7A CN115657312A (en) | 2022-11-04 | 2022-11-04 | Projection lens and projection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211379549.7A CN115657312A (en) | 2022-11-04 | 2022-11-04 | Projection lens and projection system |
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| Publication Number | Publication Date |
|---|---|
| CN115657312A true CN115657312A (en) | 2023-01-31 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211379549.7A Pending CN115657312A (en) | 2022-11-04 | 2022-11-04 | Projection lens and projection system |
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| Country | Link |
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| CN (1) | CN115657312A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116299989A (en) * | 2023-05-25 | 2023-06-23 | 歌尔光学科技有限公司 | Projection lens, vehicle-mounted HUD and vehicle |
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2022
- 2022-11-04 CN CN202211379549.7A patent/CN115657312A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116299989A (en) * | 2023-05-25 | 2023-06-23 | 歌尔光学科技有限公司 | Projection lens, vehicle-mounted HUD and vehicle |
| CN116299989B (en) * | 2023-05-25 | 2023-09-12 | 歌尔光学科技有限公司 | Projection lens, vehicle-mounted HUD and vehicle |
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