CN117741985A - Optical system and head-mounted device - Google Patents
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- CN117741985A CN117741985A CN202311839979.7A CN202311839979A CN117741985A CN 117741985 A CN117741985 A CN 117741985A CN 202311839979 A CN202311839979 A CN 202311839979A CN 117741985 A CN117741985 A CN 117741985A
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- 201000009310 astigmatism Diseases 0.000 description 15
- 239000011521 glass Substances 0.000 description 12
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- 230000009471 action Effects 0.000 description 5
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- 238000007747 plating Methods 0.000 description 2
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Abstract
An optical system and a head-mounted device. The optical system sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a semi-transparent and semi-reflective structure from a projection side to an image source side along an optical axis; the lens comprises a first lens, a second lens, a reflection polarizing structure and a phase retarder, wherein the reflection polarizing structure is arranged on the projection side of the second lens; the first lens element with positive refractive power; the second lens element with negative refractive power has a concave projection-side surface at the optical axis; the third lens element with refractive power has a concave projection-side surface at an optical axis and a convex image-source-side surface at the optical axis; the fourth lens element with positive refractive power has a convex image-source-side surface at the optical axis; the semi-transparent and semi-reflective structure is arranged on the image source side surface of the fourth lens. The optical system can adjust the diopter of the optical system, so that the resolution of the optical system is improved.
Description
Technical Field
The application relates to an optical imaging technology, in particular to an optical system and a head-mounted device.
Background
With the progress of technology and the need for socioeconomic development, the development of virtual reality technology has been rapid, and head-mounted devices (e.g., VR glasses) employing virtual reality technology have been developed. At present, an optical system in a head-mounted device generally comprises three lenses, a reflective polarizing structure, a phase retarder and a semi-transparent and semi-reflective structure, however, because the three-lens optical system has lower degree of freedom, the resolution of different diopters has some differences, and the resolution is insufficient during high diopter adjustment; however, in order to make the overall resolution of the optical system sufficient, the attaching position of the phase retarder needs to have a certain curvature, but this increases the attaching difficulty and causes a macula problem on the imaged picture.
Disclosure of Invention
In view of the foregoing, it is necessary to provide an optical system and a head-mounted device to solve the technical problem of insufficient resolution of the optical system.
An embodiment of the present disclosure provides an optical system including, in order from a projection side to an image source side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, and a half-transparent half-reflective structure; the optical system further comprises a reflection polarization structure, and the reflection polarization structure is arranged on the projection side of the second lens; the optical system further comprises a phase retarder, wherein the phase retarder is arranged between the reflection polarizing structure and the semi-transparent semi-reflective structure, and at least one lens is arranged between the phase retarder and the reflection polarizing structure; the first lens has positive refractive power; the second lens has negative refractive power, and the projection side surface of the second lens is a concave surface at the optical axis; the third lens element with refractive power has a concave projection-side surface and a convex image-source-side surface; the fourth lens element with positive refractive power has a convex image-source-side surface at an optical axis, and is movable in the optical axis direction to achieve focusing; the semi-transparent and semi-reflective structure is arranged on the image source side surface of the fourth lens.
The optical system adopts a four-piece type lens framework, and the fourth lens can move along the optical axis direction relative to the third lens so as to realize focusing, so that the framework freedom degree of the optical system can be increased, the diopter of the optical system can be regulated, and the resolution of the optical system is improved; and the surface curvature of the second lens attached to the phase retarder is smaller, so that the attaching difficulty of the phase retarder can be reduced, and the problem of yellow spots of an imaging picture can be avoided.
An embodiment of the present application further provides a head-mounted device, including a device main body and the optical system described above, where the optical system is disposed on the device main body.
The head-mounted device comprises an optical system, wherein the optical system adopts a four-piece type lens framework, and the fourth lens can move relative to the third lens along the optical axis direction so as to realize focusing, so that the framework freedom degree of the optical system can be increased, and the diopter of the optical system can be regulated, thereby improving the resolution of the optical system; and the surface curvature of the second lens attached to the phase retarder is smaller, so that the attaching difficulty can be reduced, and the problem of image yellow spots can be avoided.
Drawings
Fig. 1 is a block diagram of an optical system according to a first embodiment of the present application in a mid-focus state.
Fig. 2 is an astigmatism, distortion, and spherical aberration plot of an optical system according to a first embodiment of the present application.
Fig. 3 is a block diagram of the optical system of the first embodiment of the present application in a short focal state.
Fig. 4 is a block diagram of the optical system of the first embodiment of the present application in a tele state.
Fig. 5 is a structural diagram of an optical system of a second embodiment of the present application.
Fig. 6 is an astigmatism, distortion, and spherical aberration plot of an optical system according to a second embodiment of the present application.
Fig. 7 is a structural diagram of an optical system of a third embodiment of the present application.
Fig. 8 is an astigmatism, distortion, and spherical aberration plot of an optical system according to a third embodiment of the present application.
Fig. 9 is a structural diagram of an optical system of a fourth embodiment of the present application.
Fig. 10 is an astigmatism, distortion, and spherical aberration graph of an optical system according to a fourth embodiment of the present application.
Fig. 11 is a structural diagram of an optical system of a fifth embodiment of the present application.
Fig. 12 is an astigmatism, distortion, and spherical aberration graph of an optical system according to a fifth embodiment of the present application.
Fig. 13 is a schematic perspective view of a headset according to an embodiment of the present application.
Description of the main reference signs
Optical system 100
First lens L1
Second lens L2
Third lens L3
Fourth lens L4
Reflective polarizing structure 10
Phase retarder 20
Semi-transparent and semi-reflective structure 30
Image source plane S0
Projection side surfaces S1, S3, S5, S7
Image source side surfaces S2, S4, S6, S8
Head-mounted device 200
Device main body 201
Optical axis L
Detailed Description
Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.
Referring to fig. 1, an embodiment of the present application provides an optical system 100 including a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a transflective structure 30 sequentially from a projection side (an eye side) to an image source side along an optical axis L.
The optical system further comprises a reflective polarizing structure 10 and a phase retarder 20, wherein the reflective polarizing structure 10 is arranged on the projection side of the second lens L2; the phase retarder 20 is disposed between the reflective polarizing structure 10 and the transflective structure 30, and at least one lens is disposed between the phase retarder 20 and the reflective polarizing structure 10; the first lens element L1 with positive refractive power; the second lens element L2 with negative refractive power has a concave projection-side surface S3 on the optical axis L, the third lens element L3 with refractive power has a concave projection-side surface S5 on the optical axis L, a convex image-source-side surface S6 on the optical axis L, the fourth lens element L4 with positive refractive power has a convex image-source-side surface S8 on the optical axis L, and the fourth lens element L4 is movable along the optical axis L to achieve focusing; the half mirror structure 30 is disposed on the image source side surface S8 of the fourth lens L4.
The optical system 100 of the application adopts a four-piece lens architecture, and the fourth lens L4 can move along the direction of the optical axis L relative to the third lens L3 so as to realize focusing, so that the degree of freedom of the architecture of the optical system 100 can be increased, the diopter of the optical system 100 can be regulated, and the resolution of the optical system 100 is improved; and the curvature of the surface of the second lens L2 to which the retarder 20 is attached is smaller, so that the attaching difficulty of the retarder 20 is reduced, and the macula problem of an imaging picture is avoided.
In the present embodiment, the reflective polarizing structure 10 is a multilayer reflective polarizing film and is adhered to the projection side surface S3 of the second lens L2 by glue. The phase retarder 20 is a quarter-wave plate and is attached to the image source side surface S4 of the second lens L2 by glue. The transflective structure 30 is a transflective film and is plated on the image source side surface S8 of the fourth lens L4. In other embodiments, the reflective polarizing structure 10 and the retarder 20 may be plated on the surface of the lens, and the transflective structure 30 may be a film structure and attached to the surface of the lens. In the present embodiment, the positions where the reflective polarizing structure 10, the phase retarder 20, and the half mirror structure 30 are arranged are only one example, and are not the only arrangement.
In some embodiments, the optical system 100 satisfies the following conditional expression:
85°<FOV<120°；
where FOV is the maximum field angle of the optical system 100.
When the above-described relational expression is satisfied, the angle of view of the optical system 100 can be made large, and the imaging quality is ensured. However, when FOV is less than or equal to 85 °, the angle of view is too small to meet the design requirement; when the FOV is more than or equal to 120 degrees, the lens size is too large, the miniaturization design is not facilitated, the lens is too bent due to high distortion, and the process difficulty is high.
In some embodiments, the optical system 100 satisfies the following conditional expression:
0.7<TTL/F<1.1；
where TTL is a distance between the projection side surface S1 of the first lens L1 and the image source surface S0 of the optical system 100 on the optical axis L, and F is an effective focal length of the optical system 100.
By satisfying the above-described relational expression, imaging quality and miniaturization of the optical system 100 can be ensured. However, when TTL/f+.0.7, the size of the optical system 100 is large, thereby making the size of the head-mounted device in which the optical system 100 is installed large; when 1.1+.TTL/F, the aberration of the optical system 100 is poorly converged, thereby affecting the imaging quality of the optical system 100.
In some embodiments, the optical system 100 satisfies the following conditional expression:
0.7<IH/F<1；
IH is the image height corresponding to half of the maximum field angle of the optical system 100.
By satisfying the above-described relational expression, imaging quality and miniaturization of the optical system 100 can be ensured. However, when IH/f+.0.7, the aberration of the optical system 100 is poorly contracted, thereby affecting the imaging quality of the optical system 100; when 1+.IH/F, the size of the optical system 100 is large, so that the size of the head-mounted device in which the optical system 100 is mounted is large.
In some embodiments, the reflective polarizing structure 10 is disposed on the projection side surface S3 of the second lens L2, the phase retarder 20 is disposed on the image source side surface S4 of the second lens L2, and the optical system satisfies the following condition:
80< |R3|; and/or
80<|R4|；
Wherein R3 is a radius of curvature of the projection side surface S3 of the second lens L2 at the optical axis L, and R4 is a radius of curvature of the image source side surface S4 of the second lens L2 at the optical axis L.
In this way, the curvature of the lens surface is small, facilitating the application or plating of the retarder 20. However, when |r3| and/or |r4| is less than or equal to 80, the difficulty of attaching or plating the retarder 20 is high, and the problem of macula is caused in the imaged picture.
In some embodiments, the optical system 100 satisfies the following conditional expression:
0.9<TTL/IH<1.2；
by satisfying the above relation, the size of the optical system 100 can be ensured not to be too large, thereby facilitating miniaturization of the head-mounted apparatus in which the optical system 100 is mounted. However, when TTL/IH is less than or equal to 0.9, the resolution pressure is high, which results in excessive bending of the lens, and is unfavorable for manufacturing. When 1.2 mm+.TTL/IH, the size of the optical system 100 is too large, so that the size of the head-mounted device to which the optical system 100 is mounted is large, which is disadvantageous for miniaturization design.
In some embodiments, the fourth lens L4 satisfies the following relationship:
0.9mm≤M≤2mm；
wherein M is the moving distance of the fourth lens L4 along the direction of the optical axis L.
By satisfying the above relation, a reasonable movement space is provided for focusing, which is conducive to rapid focusing and is conducive to obtaining a reasonable focusing range. When the formula upper limit is exceeded, the reserved moving space is too large to meet the requirement of miniaturized design, and when the formula upper limit is below the formula lower limit, the reserved moving space is too small to cause too small focusing range to meet the design requirement.
In some embodiments, the optical system 100 satisfies the following conditional expression:
0≤AG23/CT2<1；
where AG23 is the distance on the optical axis L between the image source side surface S4 of the second lens L2 and the projection side surface S5 of the third lens L3, and CT2 is the distance on the optical axis L between the projection side surface S3 of the second lens L2 and the image source side surface S4 of the second lens L2.
By satisfying the above relation, aberration correction of the optical system 100 is preferable, and the overall thickness of the optical system 100 is small. When the aberration correction of the optical system 100 is poor and the distance between the image source side surface S4 of the second lens L2 and the projection side S5 of the third lens L3 on the optical axis L is large, the overall thickness of the optical system 100 is large.
In some embodiments, the optical system 100 satisfies the following conditional expression:
1<D42/IH<1.5；
wherein D42 is half of the optical effective diameter of the image source side surface S8 of the fourth lens L4.
By satisfying the above relation, the optical path design of the optical system 100 is less difficult, the aberration convergence of the optical system 100 is better, and the imaging quality is ensured, and the fourth lens L4 is small in size, which is advantageous for miniaturization of the optical system 100. However, when D42/IH is less than or equal to 1, the optical effective diameter of the image source side surface S8 of the fourth lens L4 is smaller, and the folded optical path design of the optical system 100 is difficult; when 1.5+.D42/IH+.1, the fourth lens L4 is larger in size, thereby making the head-mounted device on which the optical system 100 is mounted larger in size.
In some embodiments, the optical system 100 satisfies the following conditional expression:
4<F1/F<17；
wherein F1 is the focal length of the first lens L1.
By satisfying the above relation, the lens is helpful for converging light, avoiding excessively strong refractive power of the lens and introducing excessive aberration.
In some embodiments, the optical system 100 satisfies the following conditional expression:
-7<F2/F<-5；
wherein F2 is the focal length of the second lens L2.
By satisfying the above relation, the first lens L1 is matched to help eliminate on-axis chromatic aberration.
In some embodiments, the optical system 100 satisfies the following conditional expression:
|F3|/F>2；
Wherein F1 is the focal length of the third lens L3.
By satisfying the above relation, the aberration generated by the front lens group can be corrected, and the imaging quality can be further improved. Further, when |f3|/F >3, the imaging quality of the optical system 100 is more.
In some embodiments, the optical system 100 satisfies the following conditional expression:
5<F4/F<10；
wherein F4 is the focal length of the fourth lens L4.
By satisfying the above-described relational expression, the back focus of the optical system 100 can be reduced, and the optical system 100 can be miniaturized.
In some embodiments, the optical system 100 satisfies the following conditional expression:
|R1|/F>2；
wherein R1 is the radius of curvature of the projection side surface S1 of the first lens L1.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation.
In some embodiments, the optical system 100 satisfies the following conditional expression:
|R2|/F>1；
wherein R2 is a radius of curvature of the image source surface S2 of the first lens L1.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation. Further, when |r2|/f >2, the imaging quality is better.
In some embodiments, the optical system 100 satisfies the following conditional expression:
-7<R3/F<-2；
wherein R3 is the radius of curvature of the projection side surface S3 of the second lens L2.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation.
In some embodiments, the optical system 100 satisfies the following conditional expression:
|R4|/F>2；
wherein R4 is the radius of curvature of the image source side surface S4 of the second lens L2.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation. Further, when |r4|/f >3, the imaging quality is better.
In some embodiments, the optical system 100 satisfies the following conditional expression:
-16<R5/F<-3；
where R5 is the radius of curvature of the projection side surface S5 of the third lens L3.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation.
In some embodiments, the optical system 100 satisfies the following conditional expression:
-10<R6/F<-1；
wherein R6 is a radius of curvature of the image-source-measuring surface S6 of the third lens L3.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation.
In some embodiments, the optical system 100 satisfies the following conditional expression:
|R7|/F>2；
wherein R7 is located at the radius of curvature of the projection side surface S7 of the fourth lens L4.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation. Further, when |r7|/f >3, the imaging quality is better.
In some embodiments, the optical system 100 satisfies the following conditional expression:
-3<R8/F<-1；
wherein R8 is the radius of curvature of the image-source-measuring surface S8 of the fourth lens L4.
Reasonable setting of the radius of curvature helps correct aberrations by satisfying the above-described relation.
In some embodiments, the optical system 100 satisfies the following conditional expression:
0.8<(CT2+CT3)/CT4<3；
wherein CT3 is the distance between the projection side surface S5 of the third lens L3 and the image source side surface S6 of the second lens L2 on the optical axis L, and CT4 is the distance between the projection side surface S7 of the fourth lens L4 and the image source side surface S8 of the fourth lens L4 on the optical axis L.
By satisfying the above relation, the thickness of the lens is reasonably set, and a sufficient moving space is reserved for focusing of the fourth lens L4.
In some embodiments, the optical system 100 satisfies the following conditional expression:
2.5<CT3/CT2<5；
by satisfying the above relation, the second lens element L2 with negative refractive power can be prevented from being excessively thick, and the second lens element L2 can be prevented from excessively occupying space, thereby contributing to the miniaturization design of the optical system 100.
In some embodiments, at least one lens of the optical system 100 has an aspherical profile. In one embodiment, the projection side surface or the image source side surface of each lens may be designed to be aspherical. The aspheric design can help the optical system 100 to more effectively eliminate aberrations and improve imaging quality. In some embodiments, at least one lens in the optical system 100 may also have a spherical surface shape, and the design of the spherical surface shape may reduce the difficulty of manufacturing the lens and reduce the manufacturing cost. In some embodiments, in order to achieve the advantages of manufacturing cost, manufacturing difficulty, imaging quality, assembly difficulty, etc., the design of each lens surface in the optical system 100 may be composed of an aspherical surface and a spherical surface.
The surface type calculation of the aspherical surface can refer to an aspherical surface formula:
wherein Z is the distance from the corresponding point on the aspheric surface to the tangential plane of the surface at the optical axis L, r is the distance from the corresponding point on the aspheric surface to the optical axis L, c is the refractive index of the aspheric surface at the optical axis L, k is the conic coefficient, and Ai is the higher order term coefficient corresponding to the i-th order higher order term in the aspheric surface formula.
In some embodiments, the material of at least one lens in the optical system 100 is Plastic (PC), which may be polycarbonate, gum, or the like. In some embodiments, the material of at least one lens in the optical system 100 is Glass (GL). The lens with plastic material can reduce the production cost of the optical system 100, while the lens with glass material can withstand higher or lower temperature and has excellent optical effect and better stability. In some embodiments, lenses of different materials may be disposed in the optical system 100, i.e. a combination of glass lenses and plastic lenses may be used, but the specific configuration relationship may be determined according to practical requirements, which is not meant to be exhaustive.
The optical system 100 of the present application is described below by way of more specific examples:
First embodiment
With continued reference to fig. 1, the optical system 100 in the present embodiment includes, in order from a projection side to an image source side along an optical axis L, a first lens L1, a reflective polarizing structure 10, a second lens L2, a phase retarder 20, a third lens L3, a fourth lens L4, a transflective structure 30, and a protective glass L5.
The first lens element L1 with positive refractive power has a convex projection-side surface S1 at an optical axis L, and a concave image-source-side surface S2 of the first lens element L1 at the optical axis L.
The second lens element L2 with negative refractive power has a concave projection-side surface S3 of the second lens element L2 at the optical axis L, and a planar image-source-side surface S4 of the second lens element L2 at the optical axis L.
The third lens element L3 with positive refractive power has a concave projection-side surface S5 at the optical axis L, and a convex image-source-side surface S6 at the optical axis L of the third lens element L3.
The fourth lens element L4 with positive refractive power has a concave projection-side surface S7 at the optical axis L, and a convex image-source-side surface S8 at the optical axis L of the fourth lens element L4, wherein the fourth lens element L4 is movable along the optical axis L to achieve focusing.
The reflective polarizing structure 10 is disposed on the projection side surface S3 of the second lens L2, the transflective structure 30 is disposed on the image source side surface S8 of the fourth lens L4, and the phase retarder 20 is disposed on the image source side surface S4 of the second lens L2.
When the image projector is used, the first circularly polarized light from the image source surface S0 sequentially passes through the semi-transparent and semi-reflective structure 30 and the fourth lens L4 along the direction of the optical axis L, the polarization state is kept unchanged, then the first circularly polarized light passes through the third lens L3 and reaches the phase retarder 20, the phase retarder 20 changes the first circularly polarized light into first linearly polarized light, the first linearly polarized light passes through the second lens L2 and then is reflected by the reflective polarizing structure 10 of the projection side surface S3 of the second lens L2, so that the first linearly polarized light passes through the second lens L2 and the phase retarder 20 again, the deflection direction of the second circularly polarized light is opposite to the rotation of the first circularly polarized light, then the second circularly polarized light sequentially passes through the third lens L3 and the fourth lens L4, the second circularly polarized light sequentially passes through the fourth lens L4 and the third lens L3 and then becomes second linearly polarized light under the action of the phase retarder 20, and the second linearly polarized light sequentially passes through the second lens L2, the reflective structure 10 and the first polarizing structure L4 and the virtual polarizing device is completed, and the image projector is transmitted to the human eye image projector 1.
The lens parameters of the optical system 100 in this embodiment are shown in table 1 below. The elements from the projection plane of the optical system 100 to the image source plane S0 are sequentially arranged in the order from top to bottom in table 1, where STO characterizes the aperture (i.e., at the pupil). The R values in table 1 are radii of curvature of the corresponding surfaces of the lenses at the optical axis L. In table 1, the surface with the surface number 1 represents the projection side surface S1 of the first lens L1, the surface with the surface number 2 represents the image source side surface S2 of the first lens L1, and the rest of the lenses and the like. "thickness" means the distance on the optical axis from the current surface to the next surface. For example, the absolute value of the first value of the "thickness" of the lens is the thickness of the lens on the optical axis L, and the absolute value of the second value is the distance from the image source side surface of the lens to the latter optical surface (the projection side surface of the latter lens) on the optical axis L, wherein the thickness parameter of the aperture stop STO indicates the distance from the aperture stop STO to the projection side surface S1 of the first lens L1 on the optical axis L. The direction from the projection plane to the image source plane is default to be positive, and is negative (e.g., the distance from the projection plane to the next plane is-500, i.e., the projection plane is on the image source side of the aperture STO). The refractive index and Abbe number of each lens in the table are 587nm, the focal length of each lens is 531nm, and the R value, thickness and focal length are in millimeters (mm). The parameter data and lens surface type structure used for relational computation in the following embodiments are based on the data in the lens parameter table in the corresponding embodiments.
TABLE 1a
Referring to fig. 1, 3 and 4, fig. 3 is a structural diagram of the optical system 100 in a short focal state, fig. 1 is a structural diagram of the optical system 100 in a mid focal state, and fig. 4 is a structural diagram of the optical system 100 in a long focal state.
Table 1b shows values of the variable distance a between the fourth lens L4 and the third lens L3, the variable distance b between the corresponding fourth lens L4 and the cover glass L5 connected to the image source surface S0, the distance c from the projection surface (virtual image) to the aperture stop, and the effective focal length F of the optical system 100 in the short-focus state, the mid-focus state, and the long-focus state of the optical system 100 in table 1a, wherein the units of a, b, c, and F are all millimeters.
TABLE 1b
| Distance-variable | Short focus state (w) | Middle focus state (m) | Long focus state (t) |
| a | 2.73 | 2.00 | 0.82 |
| b | 1.15 | 1.88 | 3.06 |
| c | -4000.00 | -500.00 | -200.00 |
| F | 25.15 | 25.33 | 25.65 |
Table 1c presents the aspherical coefficients of the corresponding lens surfaces in table 1a, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th order higher order term in the aspherical surface type formula.
TABLE 1c
| Face number | K | A4 | A6 | A8 | A10 |
| S1 | 0.00000E+00 | -5.84704E-05 | 2.72430E-07 | -6.70000E-10 | 5.47465E-13 |
| S2 | 0.00000E+00 | -5.57730E-05 | 1.70636E-07 | -2.19093E-10 | -1.59982E-13 |
| S3 | 0.00000E+00 | 9.56313E-07 | -6.39078E-10 | 2.18000E-12 | 9.41977E-15 |
| S4 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S5 | 0.00000E+00 | 1.75669E-05 | -1.51879E-08 | 5.76058E-12 | 0.00000E+00 |
| S6 | 0.00000E+00 | 1.30925E-05 | -2.40000E-09 | 6.03909E-12 | 0.00000E+00 |
| S7 | 0.00000E+00 | -6.84051E-06 | 2.54528E-08 | -3.70673E-11 | 5.33098E-15 |
| S8 | 0.00000E+00 | -1.83566E-06 | 8.75130E-09 | -1.03312E-11 | 7.98681E-16 |
Referring to fig. 2, fig. 2 (a) shows the light astigmatism diagrams of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. Wherein, the abscissa along the X-axis direction represents focus offset, and the ordinate along the Y-axis direction represents image height in mm. The astigmatic curves represent the meridional imaging plane curvature T and the sagittal imaging plane curvature S, and as can be seen from fig. 2 (a), the maximum values of the arc-loss field curvature and the meridional field curvature are both less than 0.5mm, at which wavelength the astigmatism of the optical system 100 is well compensated.
Fig. 2 (b) shows a distortion graph of the optical system 100 in the first embodiment at a wavelength of 531 nm. Wherein, the abscissa along the X-axis direction represents distortion, and the ordinate along the Y-axis direction represents image height in mm. As can be seen from fig. 2 (b), the maximum distortion is less than 40% at wavelength 531nm, and the distortion of the optical system 100 is well corrected.
Fig. 2 (c) shows a longitudinal spherical aberration diagram of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. The abscissa along the X-axis represents the focus offset in mm, the ordinate along the Y-axis represents the normalized field of view, and the longitudinal spherical aberration curve represents the focus offset of light rays of different wavelengths after passing through the lenses of the optical system 100. As can be seen from fig. 2 (c), the degree of focus deviation of the light beams with different wavelengths in the present embodiment tends to be uniform, and the diffuse spots or halos in the imaging frame are effectively suppressed, which means that the imaging quality of the optical system 100 in the present embodiment is better.
Second embodiment
Referring to fig. 5, the optical system 100 in the present embodiment includes, in order from a projection side to an image source side along an optical axis L, a first lens L1, a reflective polarizing structure 10, a second lens L2, a phase retarder 20, a third lens L3, a fourth lens L4, a transflective structure 30, and a protective glass L5. The first lens element L1 with positive refractive power has a convex projection-side surface S1 at an optical axis L, and a concave image-source-side surface S2 at the optical axis L1.
The second lens element L2 with negative refractive power has a concave projection-side surface S3 of the second lens element L2 at the optical axis L, and a planar image-source-side surface S4 of the second lens element L2 at the optical axis L.
The third lens element L3 with positive refractive power has a concave projection-side surface S5 at the optical axis L, and a convex image-source-side surface S6 at the optical axis L of the third lens element L3.
The fourth lens element L4 with positive refractive power has a convex projection-side surface S7 at the optical axis L, and a convex image-source-side surface S8 at the optical axis L4, wherein the fourth lens element L4 is movable along the optical axis L to achieve focusing.
The reflective polarizing structure 10 is disposed on the projection side surface S3 of the second lens L2, the transflective structure 30 is disposed on the image source side surface S8 of the fourth lens L4, and the phase retarder 20 is disposed on the image source side surface S4 of the second lens L2.
When the image projector is used, the first circularly polarized light from the image source surface S0 sequentially passes through the semi-transparent and semi-reflective structure 30 and the fourth lens L4 along the direction of the optical axis L, the polarization state is kept unchanged, then the first circularly polarized light passes through the third lens L3 and reaches the phase retarder 20, the phase retarder 20 changes the first circularly polarized light into first linearly polarized light, the first linearly polarized light passes through the second lens L2 and then is reflected by the reflective polarizing structure 10 of the projection side surface S3 of the second lens L2, so that the first linearly polarized light passes through the second lens L2 and the phase retarder 20 again, the deflection direction of the second circularly polarized light is opposite to the rotation of the first circularly polarized light, then the second circularly polarized light sequentially passes through the third lens L3 and the fourth lens L4, the second circularly polarized light sequentially passes through the fourth lens L4 and the third lens L3 and then becomes second linearly polarized light under the action of the phase retarder 20, and the second linearly polarized light sequentially passes through the second lens L2, the reflective structure 10 and the first polarizing structure L4 and the virtual polarizing device is completed, and the image projector is transmitted to the human eye image projector 1.
The lens parameters of the optical system 100 in this embodiment are given in table 2a, wherein the definition of the names and parameters of the elements can be obtained in the first embodiment, and the details are omitted here.
TABLE 2a
Table 2b shows values of the variable distance a between the fourth lens L4 and the third lens L3, the variable distance b between the corresponding fourth lens L4 and the cover glass L5 connected to the image source surface S0, the distance c from the projection surface (virtual image) to the aperture stop, and the effective focal length F of the optical system 100 in the short-focus state, the mid-focus state, and the long-focus state of the optical system 100 in table 2a, wherein the units of a, b, c, and F are all millimeters.
TABLE 2b
| Distance-variable | Short focus state (w) | Middle focus state (m) | Long focus state (t) |
| a | 2.90 | 2.00 | 0.55 |
| b | 0.98 | 1.88 | 3.33 |
| c | -4000.00 | -500.00 | -200.00 |
| F | 25.70 | 25.66 | 25.56 |
Table 2c presents the aspherical coefficients of the corresponding lens surfaces in table 2a, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th order higher order term in the aspherical surface type formula.
TABLE 2c
| Face number | K | A4 | A6 | A8 | A10 |
| S1 | 0.00000E+00 | -5.97927E-05 | 2.19455E-07 | -3.24242E-10 | 2.63990E-15 |
| S2 | 0.00000E+00 | -5.99031E-05 | 1.61987E-07 | -8.84101E-11 | -2.59026E-13 |
| S3 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S4 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S5 | 0.00000E+00 | 1.65111E-05 | -1.93531E-08 | 5.44631E-12 | 0.00000E+00 |
| S6 | 0.00000E+00 | 1.26034E-05 | -1.37453E-08 | 1.66110E-12 | 0.00000E+00 |
| S7 | 0.00000E+00 | -9.49832E-06 | 2.44003E-08 | -3.65661E-11 | 1.73519E-14 |
| S8 | 0.00000E+00 | -1.81734E-06 | 6.28220E-09 | -7.75128E-12 | 2.72886E-15 |
Referring to fig. 6, fig. 6 (a) shows the light astigmatism diagrams of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. Wherein, the abscissa along the X-axis direction represents focus offset, and the ordinate along the Y-axis direction represents image height in mm. The astigmatic curves represent the meridional imaging plane curvature T and the sagittal imaging plane curvature S, and as can be seen from fig. 6 (a), the maximum values of the arc-loss field curvature and the meridional field curvature are both less than 0.5mm, at which wavelength the astigmatism of the optical system 100 is well compensated.
Fig. 6 (b) shows a distortion graph of the optical system 100 in the present embodiment at a wavelength of 531 nm. Wherein, the abscissa along the X-axis direction represents distortion, and the ordinate along the Y-axis direction represents image height in mm. As can be seen from fig. 6 (b), the maximum distortion is less than 40% at wavelength 531nm, and the distortion of the optical system 100 is well corrected.
Fig. 6 (c) shows a longitudinal spherical aberration diagram of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. The abscissa along the X-axis represents the focus offset in mm, the ordinate along the Y-axis represents the normalized field of view, and the longitudinal spherical aberration curve represents the focus offset of light rays of different wavelengths after passing through the lenses of the optical system 100. As can be seen from fig. 6 (c), the degree of focus deviation of the light beams with different wavelengths in the present embodiment tends to be uniform, and the diffuse spots or halos in the imaging frame are effectively suppressed, which means that the imaging quality of the optical system 100 in the present embodiment is better.
Third embodiment
Referring to fig. 7, the optical system 100 in the present embodiment includes, in order from a projection side to an image source side along an optical axis L, a first lens L1, a reflective polarizing structure 10, a second lens L2, a phase retarder 20, a third lens L3, a fourth lens L4, a half mirror structure 30, and a protective glass L5.
The first lens element L1 with positive refractive power has a convex projection-side surface S1 at an optical axis L, and a convex image-source-side surface S2 at an optical axis L of the first lens element L1.
The second lens element L2 with negative refractive power has a concave projection-side surface S3 and a convex image-source-side surface S4, respectively, of the second lens element L2 at the optical axis L.
The third lens element L3 with positive refractive power has a concave projection-side surface S5 at the optical axis L, and a convex image-source-side surface S6 at the optical axis L of the third lens element L3. In the present embodiment, the second lens L2 and the third lens L3 are cemented together.
The fourth lens element L4 with positive refractive power has a concave projection-side surface S7 at the optical axis L, and a convex image-source-side surface S8 at the optical axis L of the fourth lens element L4, wherein the fourth lens element L4 is movable along the optical axis L to achieve focusing.
The reflective polarizing structure 10 is disposed on the projection side surface S3 of the second lens L2, the transflective structure 30 is disposed on the image source side surface S8 of the fourth lens L4, and the phase retarder 20 is disposed on the image source side surface S4 of the second lens L2.
When the image projector is used, the first circularly polarized light from the image source surface S0 sequentially passes through the semi-transparent and semi-reflective structure 30 and the fourth lens L4 along the direction of the optical axis L, the polarization state is kept unchanged, then the first circularly polarized light passes through the third lens L3 and reaches the phase retarder 20, the phase retarder 20 changes the first circularly polarized light into first linearly polarized light, the first linearly polarized light passes through the second lens L2 and then is reflected by the reflective polarizing structure 10 of the projection side surface S3 of the second lens L2, so that the first linearly polarized light passes through the second lens L2 and the phase retarder 20 again, the deflection direction of the second circularly polarized light is opposite to the rotation of the first circularly polarized light, then the second circularly polarized light sequentially passes through the third lens L3 and the fourth lens L4, the second circularly polarized light sequentially passes through the fourth lens L4 and the third lens L3 and then becomes second linearly polarized light under the action of the phase retarder 20, and the second linearly polarized light sequentially passes through the second lens L2, the reflective structure 10 and the first polarizing structure L4 and the virtual polarizing device is completed, and the image projector is transmitted to the human eye image projector 1.
The lens parameters of the optical system 100 in this embodiment are given in table 3a, wherein the definition of the names and parameters of the elements can be obtained in the first embodiment, and the details are omitted here.
TABLE 3a
Table 3b shows values of the variable distance a between the fourth lens L4 and the third lens L3, the variable distance b between the corresponding fourth lens L4 and the cover glass L5 connected to the image source surface S0, the distance c from the projection surface (virtual image) to the aperture stop, and the effective focal length F of the optical system 100 in the short-focus state, the mid-focus state, and the long-focus state of the optical system 100 in table 3a, wherein the units of a, b, c, and F are all millimeters.
TABLE 3b
| Distance-variable | Short focus state (w) | Middle focus state (m) | Long focus state (t) |
| a | 1.41 | 0.97 | 0.30 |
| b | 1.02 | 1.46 | 2.13 |
| c | -4000.00 | -500.00 | -200.00 |
| F | 21.39 | 21.68 | 22.19 |
Table 3c presents the aspherical coefficients of the corresponding lens surfaces in table 3a, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th order higher order term in the aspherical surface type formula.
TABLE 3c
| Face number | K | A4 | A6 | A8 | A10 |
| S1 | 0.00000E+00 | -2.62647E-06 | 1.35780E-09 | -3.91353E-13 | -2.85662E-15 |
| S2 | 0.00000E+00 | -6.66561E-06 | -1.07532E-08 | 2.72362E-12 | -6.18354E-16 |
| S3 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S4 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S5 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S6 | 0.00000E+00 | -1.75127E-06 | 2.78072E-10 | -2.56401E-12 | -3.33181E-15 |
| S7 | 0.00000E+00 | -6.12009E-06 | 5.66266E-09 | -8.24815E-12 | 4.14685E-16 |
| S8 | 0.00000E+00 | -3.59842E-07 | 3.79792E-10 | 2.10028E-12 | -1.47772E-15 |
Referring to fig. 8, fig. 8 (a) shows the light astigmatism diagrams of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. Wherein, the abscissa along the X-axis direction represents focus offset, and the ordinate along the Y-axis direction represents image height in mm. The astigmatic curves represent the meridional imaging plane curvature T and the sagittal imaging plane curvature S, and as can be seen from fig. 8 (a), the maximum values of the arc-loss field curvature and the meridional field curvature are both less than 0.5mm, at which wavelength the astigmatism of the optical system 100 is well compensated.
Fig. 8 (b) shows a distortion graph of the optical system 100 in the present embodiment at a wavelength of 531 nm. Wherein, the abscissa along the X-axis direction represents distortion, and the ordinate along the Y-axis direction represents image height in mm. As can be seen from fig. 8 (b), the maximum distortion is less than 40% at wavelength 531nm, and the distortion of the optical system 100 is well corrected.
Fig. 8 (c) shows a longitudinal spherical aberration diagram of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. The abscissa along the X-axis represents the focus offset in mm, the ordinate along the Y-axis represents the normalized field of view, and the longitudinal spherical aberration curve represents the focus offset of light rays of different wavelengths after passing through the lenses of the optical system 100. As can be seen from fig. 8 (c), the degree of focus deviation of the light beams with different wavelengths in the present embodiment tends to be uniform, and the diffuse spots or halos in the imaging frame are effectively suppressed, which means that the imaging quality of the optical system 100 in the present embodiment is better.
Fourth embodiment
Referring to fig. 9, the optical system 100 in the present embodiment includes, in order from a projection side to an image source side along an optical axis L, a first lens L1, a reflective polarizing structure 10, a second lens L2, a phase retarder 20, a third lens L3, a fourth lens L4, a half mirror structure 30, and a protective glass L5.
The first lens element L1 with positive refractive power has a concave projection-side surface S1 at an optical axis L, and a convex image-source-side surface S2 at the optical axis L1.
The second lens element L2 with negative refractive power has a concave projection-side surface S3 and a convex image-source-side surface S4, respectively, of the second lens element L2 at the optical axis L.
The third lens element L3 with positive refractive power has a concave projection-side surface S5 at the optical axis L, and a convex image-source-side surface S6 at the optical axis L of the third lens element L3. In the present embodiment, the second lens L2 and the third lens L3 are cemented together.
The fourth lens element L4 with positive refractive power has a concave projection-side surface S7 at the optical axis L, and a convex image-source-side surface S8 at the optical axis L of the fourth lens element L4, wherein the fourth lens element L4 is movable along the optical axis L to achieve focusing.
The reflective polarizing structure 10 is disposed on the projection side surface S3 of the second lens L2, the transflective structure 30 is disposed on the image source side surface S8 of the fourth lens L4, and the phase retarder 20 is disposed on the image source side surface S4 of the second lens L2.
When the image projector is used, the first circularly polarized light from the image source surface S0 sequentially passes through the semi-transparent and semi-reflective structure 30 and the fourth lens L4 along the direction of the optical axis L, the polarization state is kept unchanged, then the first circularly polarized light passes through the third lens L3 and reaches the phase retarder 20, the phase retarder 20 changes the first circularly polarized light into first linearly polarized light, the first linearly polarized light passes through the second lens L2 and then is reflected by the reflective polarizing structure 10 of the projection side surface S3 of the second lens L2, so that the first linearly polarized light passes through the second lens L2 and the phase retarder 20 again, the deflection direction of the second circularly polarized light is opposite to the rotation of the first circularly polarized light, then the second circularly polarized light sequentially passes through the third lens L3 and the fourth lens L4, the second circularly polarized light sequentially passes through the fourth lens L4 and the third lens L3 and then becomes second linearly polarized light under the action of the phase retarder 20, and the second linearly polarized light sequentially passes through the second lens L2, the reflective structure 10 and the first polarizing structure L4 and the virtual polarizing device is completed, and the image projector is transmitted to the human eye image projector 1.
The parameters of each lens of the optical system 100 in this embodiment are given in table 4a, wherein the names and parameters of each element can be defined in the first embodiment, and the description thereof is omitted herein.
TABLE 4a
Table 4b shows values of the variable distance a between the fourth lens L4 and the third lens L3, the variable distance b between the corresponding fourth lens L4 and the cover glass L5 connected to the image source surface S0, the distance c from the projection surface (virtual image) to the aperture stop, and the effective focal length F of the optical system 100 in the short-focus state, the mid-focus state, and the long-focus state of the optical system 100 in table 4a, wherein the units of a, b, c, and F are all millimeters.
TABLE 4b
| Distance-variable | Short focus state (w) | Middle focus state (m) | Long cokeStatus (t) |
| a | 1.63 | 1.12 | 0.30 |
| b | 0.12 | 1.52 | 2.35 |
| c | -4000.00 | -500.00 | -200.00 |
| F | 24.00 | 24.60 | 25.50 |
Table 4c presents the aspherical coefficients of the corresponding lens surfaces in table 4a, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th order higher order term in the aspherical surface type formula.
TABLE 4c
| Face number | K | A4 | A6 | A8 | A10 |
| S1 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S2 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S3 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S4 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S5 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S6 | 0.00000E+00 | -5.77404E-06 | 5.14503E-09 | -7.72789E-12 | 2.94635E-15 |
| S7 | 0.00000E+00 | -1.47021E-06 | -2.45181E-09 | 1.16861E-12 | 3.60618E-16 |
| S8 | 0.00000E+00 | 8.39239E-07 | -7.55912E-10 | 1.82031E-13 | 4.30677E-16 |
Referring to fig. 10, fig. 10 (a) shows the light astigmatism diagrams of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. Wherein, the abscissa along the X-axis direction represents focus offset, and the ordinate along the Y-axis direction represents image height in mm. The astigmatic curves represent the meridional imaging plane curvature T and the sagittal imaging plane curvature S, and as can be seen from fig. 10 (a), the maximum values of the arc-loss field curvature and the meridional field curvature are both less than 0.2mm, at which wavelength the astigmatism of the optical system 100 is well compensated.
Fig. 10 (b) shows a distortion graph of the optical system 100 in the present embodiment at a wavelength of 531 nm. Wherein, the abscissa along the X-axis direction represents distortion, and the ordinate along the Y-axis direction represents image height in mm. As can be seen from fig. 10 (b), the maximum distortion is less than 40% at the wavelength of 531nm, and the distortion of the optical system 100 is well corrected.
Fig. 10 (c) shows a longitudinal spherical aberration diagram of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. The abscissa along the X-axis represents the focus offset in mm, the ordinate along the Y-axis represents the normalized field of view, and the longitudinal spherical aberration curve represents the focus offset of light rays of different wavelengths after passing through the lenses of the optical system 100. As can be seen from fig. 10 (c), the degree of focus deviation of the light beams with different wavelengths in the present embodiment tends to be uniform, and the diffuse spots or halos in the imaging frame are effectively suppressed, which means that the imaging quality of the optical system 100 in the present embodiment is better.
Fifth embodiment
Referring to fig. 11, the optical system 100 in the present embodiment includes, in order from a projection side to an image source side along an optical axis L, a first lens L1, a reflective polarizing structure 10, a second lens L2, a phase retarder 20, a third lens L3, a fourth lens L4, a transflective structure 30, and a protective glass L5.
The first lens element L1 with positive refractive power has a concave projection-side surface S1 at an optical axis L, and a convex image-source-side surface S2 at the optical axis L1.
The second lens element L2 with negative refractive power has a concave projection-side surface S3 and a convex image-source-side surface S4, respectively, of the second lens element L2 at the optical axis L.
The third lens element L3 with negative refractive power has a concave projection-side surface S5 at the optical axis L, and a convex image-source-side surface S6 at the optical axis L3.
The fourth lens element L4 with positive refractive power has a concave projection-side surface S7 at the optical axis L, and a convex image-source-side surface S8 at the optical axis L4.
The reflective polarizing structure 10 is disposed on the projection side surface S3 of the second lens L2, the transflective structure 30 is disposed on the image source side surface S8 of the fourth lens L4, and the phase retarder 20 is disposed on the image source side surface S4 of the second lens L2.
When the image projector is used, the first circularly polarized light from the image source surface S0 sequentially passes through the semi-transparent and semi-reflective structure 30 and the fourth lens L4 along the direction of the optical axis L, the polarization state is kept unchanged, then the first circularly polarized light passes through the third lens L3 and reaches the phase retarder 20, the phase retarder 20 changes the first circularly polarized light into first linearly polarized light, the first linearly polarized light passes through the second lens L2 and then is reflected by the reflective polarizing structure 10 of the projection side surface S3 of the second lens L2, so that the first linearly polarized light passes through the second lens L2 and the phase retarder 20 again, the deflection direction of the second circularly polarized light is opposite to the rotation of the first circularly polarized light, then the second circularly polarized light sequentially passes through the third lens L3 and the fourth lens L4, the second circularly polarized light sequentially passes through the fourth lens L4 and the third lens L3 and then becomes second linearly polarized light under the action of the phase retarder 20, and the second linearly polarized light sequentially passes through the second lens L2, the reflective structure 10 and the first polarizing structure L4 and the virtual polarizing device is completed, and the image projector is transmitted to the human eye image projector 1.
The lens parameters of the optical system 100 in this embodiment are given in table 5a, wherein the definition of the names and parameters of the elements can be obtained in the first embodiment, and the details are omitted here.
TABLE 5a
Table 5b shows values of the variable distances between the fourth lens L4 and the third lens L3, the variable distances b between the corresponding fourth lens L4 and the cover glass L5 connected to the image source surface S0, the distance c from the projection surface (virtual image) to the aperture stop, and the effective focal length F of the optical system 100 in the short-focus state, the mid-focus state, and the long-focus state of the optical system 100 in table 5a, wherein the units of a, b, c, and F are all millimeters.
TABLE 5b
| Distance-variable | Short focus state (w) | Middle focus state (m) | Long focus state (t) |
| a | 1.50 | 1.06 | 0.36 |
| b | 1.00 | 1.43 | 2.14 |
| c | -4000.00 | -500.00 | -200.00 |
| F | 23.15 | 23.60 | 24.40 |
Table 5c presents the aspherical coefficients of the corresponding lens surfaces in table 5a, where K is a conic coefficient and Ai is a coefficient corresponding to the i-th order higher order term in the aspherical surface type formula.
TABLE 5c
| Face number | K | A4 | A6 | A8 | A10 |
| S1 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S2 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 | 0.00000E+00 |
| S3 | 0.00000E+00 | -1.41898E-06 | -1.58199E-09 | 5.02760E-12 | -3.85103E-15 |
| S4 | 0.00000E+00 | -4.46424E-06 | 5.32709E-09 | -4.10103E-12 | -1.03114E-15 |
| S5 | 0.00000E+00 | -4.46424E-06 | 5.32709E-09 | -4.10103E-12 | -1.03114E-15 |
| S6 | 0.00000E+00 | -6.97165E-06 | 3.49522E-10 | -3.12632E-13 | 0.00000E+00 |
| S7 | 0.00000E+00 | -2.10415E-06 | -8.09791E-09 | 6.49611E-12 | -3.50322E-15 |
| S8 | 0.00000E+00 | 5.47887E-07 | -7.92888E-10 | -6.70676E-13 | 5.37112E-16 |
Referring to fig. 12, fig. 12 (a) shows the light astigmatism diagrams of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. Wherein, the abscissa along the X-axis direction represents focus offset, and the ordinate along the Y-axis direction represents image height in mm. The astigmatic curves represent the meridional imaging plane curvature T and the sagittal imaging plane curvature S, and as can be seen from fig. 12 (a), the maximum values of the arc-loss field curvature and the meridional field curvature are both less than 0.2mm, at which wavelength the astigmatism of the optical system 100 is well compensated.
Fig. 12 (b) shows a distortion graph of the optical system 100 in the present embodiment at a wavelength of 531 nm. Wherein, the abscissa along the X-axis direction represents distortion, and the ordinate along the Y-axis direction represents image height in mm. As can be seen from fig. 12 (b), the maximum distortion is less than 40% at the wavelength of 531nm, and the distortion of the optical system 100 is well corrected.
Fig. 12 (c) shows a longitudinal spherical aberration diagram of the optical system 100 in the present embodiment at wavelengths of 454nm, 531nm, 623 nm. The abscissa along the X-axis represents the focus offset in mm, the ordinate along the Y-axis represents the normalized field of view, and the longitudinal spherical aberration curve represents the focus offset of light rays of different wavelengths after passing through the lenses of the optical system 100. As can be seen from fig. 12 (c), the degree of focus deviation of the light beams with different wavelengths in the present embodiment tends to be uniform, and the diffuse spots or halos in the imaging frame are effectively suppressed, which means that the imaging quality of the optical system 100 in the present embodiment is better.
Table 6 shows values of FOV, TTL/F, IH/F, |r|, TTL/IH, M, AG23/CT2, and D42/IH in the optical system 100 of the first to fifth embodiments.
TABLE 6
Table 7 shows values of F1/F, F2/F, F3/F, F4/F, R1/F, R2/F, R3/F, R4/F, R5/F, R6/F, R7/F, R8/F, (CT2+CT3)/CT 4, CT3/CT2 in the optical system 100 of the first embodiment to the fifth embodiment.
TABLE 7
| Relation/embodiment | First embodiment | Second embodiment | Third embodiment | Fourth embodiment | Fifth embodiment |
| F1/F | 12.64414 | 16.77043 | 5.516597 | 9.916667 | 4.146868 |
| F2/F | -5.00994 | -6.57588 | -6.63862 | -6.79167 | -6.34989 |
| |F3|/F | 8.827038 | 4.669261 | 18.09257 | 19.41667 | 54.6868 |
| F4/F | 9.582505 | 8.832685 | 6.31136 | 6.958333 | 5.140389 |
| |R1|/F | 3.375752 | 3.269155 | 7.862072 | 84.1501 | 54.1418 |
| |R2|/F | 6.477168 | 5.018248 | 4.84414 | 4.84889 | 2.11425 |
| R3/F | -3.10534 | -6.08048 | -2.6882 | -2.29161 | -2.51652 |
| |R4|/F | 3.98E+08 | 3.89E+09 | 5.50581 | 3.99998 | 7.06277 |
| R5/F | -6.03575 | -15.2407 | -5.50581 | -3.99998 | -7.06277 |
| R6/F | -1.75827 | -3.68626 | -3.589 | -2.95967 | -9.30908 |
| |R7|/F | 3.76909 | 32.81266 | 4.57077 | 3.42085 | 6.1771 |
| R8/F | -2.22007 | -2.78066 | -2.00831 | -1.85241 | -1.95705 |
| (CT2+CT3)/CT4 | 2.53 | 1.263644 | 1.186045 | 0.975481 | 0.816838 |
| CT3/CT2 | 3.240223 | 2.538834 | 4.623463 | 4.928477 | 2.663703 |
Referring to fig. 13, an embodiment of the present application further provides a head-mounted device 200, including a device main body 201 and the optical system 100 described above, where the optical system 100 is disposed on the device main body 201. Alternatively, the headset 200 may include, but is not limited to, VR glasses, VR and AR glasses, AR helmets, and the like.
Finally, it should be noted that the above embodiments are merely for illustrating the technical solution of the present application and not for limiting, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application.
Claims (10)
1. An optical system is characterized by comprising a first lens, a second lens, a third lens, a fourth lens and a semi-transparent and semi-reflective structure in sequence from a projection side to an image source side along an optical axis;
the optical system further comprises a reflection polarization structure, and the reflection polarization structure is arranged on the projection side of the second lens;
the optical system further comprises a phase retarder, wherein the phase retarder is arranged between the reflection polarizing structure and the semi-transparent semi-reflective structure, and at least one lens is arranged between the phase retarder and the reflection polarizing structure;
The first lens has positive refractive power;
the second lens has negative refractive power, and the projection side surface of the second lens is a concave surface at the optical axis;
the third lens element with refractive power has a concave projection-side surface and a convex image-source-side surface;
the fourth lens element with positive refractive power has a convex image-source-side surface at an optical axis, and is movable in the optical axis direction to achieve focusing;
the semi-transparent and semi-reflective structure is arranged on the image source side surface of the fourth lens.
2. The optical system of claim 1, wherein the optical system satisfies the following conditional expression:
85°≦FOV<120°；
wherein FOV is the maximum field angle of the optical system.
3. The optical system of claim 1, wherein the optical system satisfies the following conditional expression:
0.7<TTL/F<1.1；
wherein TTL is a distance between a projection side surface of the first lens and the image source surface of the optical system on an optical axis, and F is an effective focal length of the optical system.
4. The optical system of claim 1, wherein the optical system satisfies the following conditional expression:
0.7<IH/F<1；
Wherein IH is the image height corresponding to half of the maximum field angle of the optical system, and F is the distance between the projection side surface of the first lens and the image source surface of the optical system on the optical axis.
5. The optical system of claim 1, wherein the reflective polarizing structure is disposed on a projection side surface of the second lens, and the phase retarder is disposed on an image source side surface of the second lens, the optical system satisfying the following conditional expression:
80< |R3|; and/or
80<|R4|；
Wherein R3 is a radius of curvature of the projection side surface of the second lens at the optical axis, and R4 is a radius of curvature of the image source side surface of the second lens at the optical axis.
6. The optical system of claim 1, wherein the optical system satisfies the following conditional expression:
0.94<TTL/IH<1.2；
wherein TTL is a distance between a projection side surface of the first lens and the image source surface of the optical system on an optical axis, and IH is an image height corresponding to half of a maximum field angle of the optical system.
7. The optical system of claim 1, wherein the fourth lens satisfies the following relationship:
0.9mm≤M≤2mm；
wherein M is the moving distance of the fourth lens along the optical axis direction.
8. The optical system of claim 1, wherein the optical system satisfies the following conditional expression:
0≤AG23/CT2<1；
where AG23 is a distance on the optical axis between the image source side surface of the second lens and the projection side surface of the third lens, and CT2 is a distance on the optical axis between the projection side surface of the second lens and the image source side surface of the second lens.
9. The optical system of claim 1, wherein the optical system satisfies the following conditional expression:
1<D42/IH<1.5；
wherein D42 is half of the optical effective diameter of the image source side surface of the fourth lens, and IH is the image height corresponding to the maximum field angle of the optical system.
10. A head-mounted device comprising a device body and the optical system according to any one of claims 1 to 9, the optical system being provided to the device body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311839979.7A CN117741985A (en) | 2023-12-28 | 2023-12-28 | Optical system and head-mounted device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311839979.7A CN117741985A (en) | 2023-12-28 | 2023-12-28 | Optical system and head-mounted device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117741985A true CN117741985A (en) | 2024-03-22 |
Family
ID=90283225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311839979.7A Pending CN117741985A (en) | 2023-12-28 | 2023-12-28 | Optical system and head-mounted device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117741985A (en) |
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2023
- 2023-12-28 CN CN202311839979.7A patent/CN117741985A/en active Pending
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