Disclosure of Invention
Aiming at the defects in the prior art, the technical problem mainly solved by the embodiment of the application is to provide an eyepiece lens and an eyepiece optical system, which can be suitable for AR display, and the projection lens is small in size and light in weight.
The aim of the embodiment of the application is realized by the following technical scheme:
in order to solve the above technical problems, in a first aspect, an embodiment of the present application provides an eyepiece lens, including a first lens, a second lens, a third lens, and a fourth lens, which are sequentially disposed along a common optical axis between an image side and an object side;
the first lens is a convex-concave lens, has positive focal power, the convex surface of the first lens is close to the image side, and the concave surface of the first lens is close to the object side;
the second lens is a biconvex lens and has positive focal power;
the third lens is a concave-convex lens and has negative focal power, the concave surface of the third lens is close to the image side, and the convex surface of the third lens is close to the object side;
the fourth lens is a biconvex lens and has positive focal power.
In some embodiments, the first lens relative aperture is greater than 1:3.5, the second lens relative aperture is greater than 1:1.5, the third lens relative aperture is greater than 1:1, and the fourth lens relative aperture is greater than 1:1.
in some embodiments, the first lens, the second lens, the third lens, and the fourth lens are all aspheric lenses.
In some embodiments, the first lens, the second lens, the third lens, and the fourth lens each have a radius of less than or equal to 10mm.
In some embodiments, the material of the first lens, the second lens, the third lens, the fourth lens is an optical glass or an optical resin.
In some embodiments, the eyepiece lens has an effective focal length of 14.3mm.
In some embodiments, the eyepiece lens has an exit pupil distance greater than or equal to 20mm and an exit pupil diameter greater than or equal to 4mm.
In some embodiments, the eyepiece lens has a diagonal full field angle greater than or equal to 40 °.
In order to solve the above technical problem, in a second aspect, an embodiment of the present application provides an eyepiece optical system, including: the eyepiece lens according to any one of the first aspect and a display chip, wherein the display chip is disposed in an object side direction of the eyepiece lens and is coaxial with the eyepiece lens, and the display chip is smaller than or equal to 0.39 inches in size.
In some embodiments, the display chip size is 0.39 inches.
Compared with the prior art, the application has the beneficial effects that: in contrast to the situation in the prior art, the embodiment of the application provides an eyepiece lens and an eyepiece optical system, wherein the eyepiece lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along a common optical axis between an image side and an object side, wherein other lenses except the third lens have negative focal power, other lenses except the fourth lens and the second lens have positive focal power, and other lenses except the fourth lens and the second lens are concave-convex lenses.
Detailed Description
The present application will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present application, but are not intended to limit the application in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present application.
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
Moreover, the words "first," "second," "third," and the like as used herein do not limit the data and order of execution, but merely distinguish between identical or similar items that have substantially the same function and effect.
In order to facilitate the definition of the connection structure, the application performs the position definition of the component by taking the light path advancing/emergent direction of the optical axis as a reference.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used in this specification includes any and all combinations of one or more of the associated listed items.
In addition, the technical features of the embodiments of the present application described below may be combined with each other as long as they do not collide with each other.
In particular, embodiments of the present application are further described below with reference to the accompanying drawings.
Embodiment one:
referring to fig. 1, a schematic structural diagram of an eyepiece optical system according to an embodiment of the present application is shown, where an eyepiece lens of the eyepiece optical system includes, in order from an image side to an object side, a lens assembly including: a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4.
The first lens E1 is a convex-concave lens, and has positive focal power, and its convex surface S1 is close to the image side, and its concave surface S2 is close to the object side.
The second lens E2 is a biconvex lens, and has positive focal power, and a convex surface S3 thereof is close to the image side and the first lens E1 and a convex surface S4 thereof are close to the object side.
The third lens E3 is a concave-convex lens, and has negative focal power, and the concave surface S5 thereof is close to the image side and the convex surfaces S6 and E2 are close to the object side.
The fourth lens E4 is a biconvex lens, and has positive focal power, and a convex surface S7 thereof is close to the image side and convex surfaces S8 and E3 are close to the object side.
In some embodiments, the relative aperture of the first lens E1 is greater than 1:3.5, the relative aperture of the second lens E2 is greater than 1:1.5, the relative aperture of the third lens E3 is larger than 1:1, and the relative aperture of the fourth lens E4 is larger than 1:1 to ensure the light flux of the eyepiece optical system.
For example, in the embodiment of the present application, the relative aperture of the first lens E1 is 1:3.02, the relative aperture of the second lens E2 is 1:1.13, the relative aperture of the third lens E3 is 1:0.52, the relative aperture 1 of the fourth lens E4: 0.64.
in some embodiments, each lens of the eyepiece lens may be a separate lens or a doublet lens.
In the embodiment of the present application, the materials of the first lens E1, the second lens E2, the third lens E3, and the fourth lens E4 are all optical resins, which is light in weight and strong in portability.
In other embodiments, the material of each lens of the eyepiece lens may be optical glass.
Wherein, the surface parameters of each lens of the eyepiece lens can be set to proper values. In the embodiment of the present application, the surface parameters of each lens of the eyepiece lens are shown in table 1 below.
Table 1 surface parameters of each lens in eyepiece lens
The first lens E1, the second lens E2, the third lens E3, and the fourth lens E4 are aspheric lenses.
The aspherical cone coefficient value of each lens and the aspherical coefficient of each order can be set to appropriate values. The aspherical cone coefficient values and the aspherical coefficients of each lens in the embodiment of the present application are shown in the following table 2, wherein K is an aspherical cone coefficient, and a1, a2, a3, a4, a5 correspond to 2, 4, 6, 8, and 10 order aspherical coefficients, respectively.
In other embodiments, the first, second, third, and fourth lenses E1, E2, E3, E4 may be spherical mirrors.
Table 2 aspherical cone coefficient values and respective orders of aspherical coefficients of lenses in eyepiece lenses
Based on the above structure, the optical performance parameters of the eyepiece lens are shown in the following table 3
Table 3 optical performance parameters of eyepiece lenses
As can be seen from table 3, the effective focal length of the eyepiece lens is 14.3mm, and the exit pupil distance is 22mm, i.e. the effective focal length and the exit pupil distance of the eyepiece lens are smaller, so that the distance between the human eye and the image source can be effectively shortened, the volume of the equipment using the eyepiece lens can be reduced, and the miniaturized design can be realized; the full angle of view of the eyepiece lens is 40 degrees, the diameter of the exit pupil is greater than or equal to 4mm, and the eye movement range is 8×8mm, so that the range observed by human eyes can be reached, and the resolution of human eyes can be fully exerted.
In other embodiments, the eyepiece optical system further includes a display chip P1, where the display chip P1 is disposed in an object side direction of the eyepiece lens and is coaxial with the eyepiece lens, and the display chip P1 may be less than or equal to 0.39 inches for providing an image source of the eyepiece optical system.
The display chip P1 used may be Lcos, micro-LED or DLP. When the display chip P1 uses a chip that cannot emit light such as Lcos or DLP, the eyepiece lens has a visible light band, so that an illumination portion is required to be added to the eyepiece optical system, and an LED or a laser light source can be used for the illumination portion.
In this example, the display chip P1 is an OLED with a size of 0.39 inch and a resolution of 1920×1080P, and the pixel size of the chip is 4.5 μm and the limiting resolution is 111 lp/mm. The use of a 0.39 inch display chip eliminates the graining phenomenon, results in a larger diagonal full field angle and less distortion, thereby fully exploiting the optical performance of the eyepiece optics.
The imaging quality of the eyepiece optical system is detected as follows.
Fig. 2 is an MTF diagram of the eyepiece optical system shown in fig. 1, where the MTF (modulation transfer function) can comprehensively reflect the imaging quality of the optical system, and the smoother the curve shape, the higher the height relative to the X-axis, and the better the imaging quality of the system. As can be seen from fig. 2, the MTF curve is smoother, and the MTF of the eyepiece optical system is > 0.2 at a spatial frequency of 100 lp/mm, which is much higher than the limit resolution of 0.5 times. For the eyepiece optical system, the limiting resolution of which the resolution is more than 0.5 times can be considered to have a good imaging effect, that is, the aberration of the eyepiece optical system in the embodiment is well corrected, and the imaging quality is good.
Fig. 3 is a defocused MTF chart of the eyepiece optical system shown in fig. 1, and as can be seen from fig. 3, the MTF of the eyepiece optical system at a spatial frequency of 55 lp/mm is not less than 0.2, and a focal depth of ±0.3mm is supported, i.e. the eyepiece optical system in the embodiment has a good imaging effect.
Fig. 4 is a diagram of field curvature and distortion of the eyepiece optical system shown in fig. 1, wherein the left side is a field curvature curve and the right side is a distortion curve. The field curvature is an aberration of a curved image formed by an object plane, and is characterized by a meridian field curvature and a sagittal field curvature, and the excessive radial field curvature and the sagittal field curvature can seriously affect the off-axis light imaging quality of an optical system. As can be seen from fig. 4, the curvature of field is in the range of ±0.08mm, i.e. the curvature of field of the eyepiece optical system is corrected to a smaller range. Meanwhile, when the distortion of the system is less than 4%, the distortion is difficult to be perceived by human eyes, and as can be seen from fig. 4, the maximum distortion of the eyepiece optical system is less than 3%, namely, the field curvature and distortion of the eyepiece optical system in the embodiment are small, and the imaging effect is good.
Fig. 5 is an axial aberration diagram of the eyepiece optical system shown in fig. 1, and as can be seen from fig. 5, the axial aberration of the eyepiece optical system is small.
Fig. 6 is a dot pattern of the eyepiece optical system shown in fig. 1, wherein the dot pattern reflects the imaging geometry of the optical system, and in the image quality evaluation, the intensity of the available dot pattern more intuitively reflects and measures the imaging quality of the system, and the smaller the RMS radius of the dot pattern, the smaller the aberration and the better the imaging quality of the system are proved. As shown in the figure, the RMS radius is controlled within 4.5 mu m, namely the spot size of each view field of the eyepiece lens system is smaller than one pixel, so that the spot of each view field is small, the aberration correction ratio is good, and the imaging quality of the eyepiece lens system is good.
From the above data, the eyepiece optical system is simple in structure, small in size, good in aberration correction and excellent in imaging quality.
Embodiment two:
referring to fig. 7, a schematic structural diagram of an eyepiece optical system according to another embodiment of the present application is shown, where an eyepiece lens of the eyepiece optical system includes, in order from an image side to an object side, a lens assembly including: a first lens E5, a second lens E6, a third lens E7, and a fourth lens E8.
The first lens E5 is a convex-concave lens, and has positive focal power, and its convex surface S9 is close to the image side, and its concave surface S10 is close to the object side.
The second lens E6 is a biconvex lens, and has a positive focal power, and a convex surface S11 near the image side and convex surfaces S12 near the object side of the first lens E5.
The third lens E7 is a concave-convex lens, and has negative focal power, and the concave surface S13 thereof is close to the image side, and the convex surfaces S14 thereof are close to the object side.
The fourth lens E8 is a biconvex lens, and has a positive power, and a convex surface S15 thereof is close to the image side and convex surfaces S16 of the third lens E3 and E16 are close to the object side.
In the embodiment of the present application, the relative aperture of the first lens E1 is 1:3.0, the relative aperture of the second lens E2 is 1:1.13, the relative aperture of the third lens E3 is 1:0.52, the relative aperture 1 of the fourth lens E4: 0.63.
in the embodiment of the present application, the materials of the first lens E5, the second lens E6, the third lens E7 and the fourth lens E8 are all optical resins, which is light in weight and strong in portability.
In the embodiment of the present application, the surface parameters of each lens of the eyepiece lens are shown in table 4 below.
Table 4 surface parameters of each lens in eyepiece lens
The aspherical cone coefficients and the aspherical coefficients of the first lens E1, the second lens E2, the third lens E3, and the fourth lens E4 are shown in table 5 below, K is an aspherical cone coefficient, and a1, a2, a3, a4, and a5 correspond to 2, 4, 6, 8, and 10 order aspherical coefficients, respectively.
Table 5 aspherical cone coefficient value of each lens in eyepiece lens and each order aspherical coefficient
Based on the above structure, the optical performance parameters of the eyepiece lens are shown in the following table 6
Table 6 optical performance parameters of eyepiece systems
As can be seen from table 6, the effective focal length of the eyepiece lens is 14.3mm, and the exit pupil distance is 22mm, i.e. the effective focal length and the exit pupil distance of the eyepiece lens are smaller, so that the distance between eyes and an image source can be effectively shortened, the volume of equipment applying the eyepiece system can be reduced, and the miniaturized design is realized; the full angle of view of the eyepiece lens is 40 degrees, the diameter of the exit pupil is more than or equal to 4mm, and the eye movement range is 8×8mm, so that the range observed by human eyes can be reached, and the resolution of human eyes can be fully exerted.
In this embodiment, the eyepiece optical system further includes a display chip P2, where the display chip P2 is disposed in the object side direction of the eyepiece lens and is coaxial with the eyepiece lens, and is used for providing an image source of the eyepiece optical system.
In this embodiment, the display chip P2 is a flexible OLED with a size of 0.39 inch, a resolution of 1920×1080P, and a chip pixel size of 4.5 μm, and a limiting resolution of 111 lp/mm. The 0.39 inch display chip can eliminate granulation, obtain a larger diagonal full-field angle and smaller distortion, and meanwhile, the bendable display chip can be subjected to surface bending at a certain angle, so that the capability of correcting the field curvature of the system is realized, and the optical performance of the eyepiece optical system is fully exerted.
The performance of the eyepiece system is examined below.
Fig. 8 is an MTF diagram of the eyepiece optical system shown in fig. 7, and as can be seen from fig. 8, the MTF curve is smoother, and the MTF of the eyepiece optical system at a spatial frequency of 100 lp/mm is > 0.2, which is far higher than the limit resolution of 0.5 times, i.e., the aberration of the eyepiece optical system in this embodiment is well corrected, and the imaging quality is excellent.
Fig. 9 is a defocused MTF diagram of the eyepiece optical system shown in fig. 7, and as can be seen from fig. 9, the MTF of the eyepiece optical system at a spatial frequency of 55 lp/mm is equal to or greater than 0.2, and a focal depth of ±0.3mm is supported, i.e., the eyepiece optical system in this embodiment has a good imaging effect.
Fig. 10 is a graph of curvature of field and distortion of the eyepiece optical system shown in fig. 7, and it can be seen from fig. 10 that curvature of field is in the range of ±0.01mm, so that it can be seen that curvature of field of the eyepiece optical system is corrected to a very small range when the flexible display chip P2 is used. Meanwhile, as can be seen from fig. 10, the maximum distortion of the eyepiece lens system is less than 3%, that is, the curvature of field and distortion of the eyepiece lens system in this embodiment are small, and the imaging effect is good.
Fig. 11 is an axial aberration diagram of the eyepiece optical system shown in fig. 7, and as can be seen from fig. 11, the axial aberration of the eyepiece optical system is small.
Fig. 12 is a point chart of the eyepiece system shown in fig. 7, and as shown in fig. 12, the RMS radius is controlled within 4.5 μm, that is, the spot size of each field of view of the eyepiece system is smaller than one pixel, so that the spot size of each field of view is small, aberration correction is better, and the imaging quality of the eyepiece optical system is good.
From the above data, the eyepiece optical system is simple in structure, small in size, good in aberration correction and excellent in imaging quality.
The embodiment of the application provides an eyepiece lens and an eyepiece optical system, wherein the eyepiece lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along a common optical axis between an image side and an object side, wherein other lenses except the third lens have negative focal power and positive focal power, and other lenses except the first lens and the second lens are concave-convex lenses.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; the technical features of the above embodiments or in the different embodiments may also be combined within the idea of the application, the steps may be implemented in any order, and there are many other variations of the different aspects of the application as described above, which are not provided in detail for the sake of brevity; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.