WO2018094851A1

WO2018094851A1 - Camera lens having 2p structure, head-mounted display optical system, and head-mounted apparatus

Info

Publication number: WO2018094851A1
Application number: PCT/CN2016/114047
Authority: WO
Inventors: 杨春
Original assignee: 歌尔科技有限公司
Priority date: 2016-11-28
Filing date: 2016-12-31
Publication date: 2018-05-31
Also published as: CN106773010B; CN106773010A

Abstract

A camera lens having a 2P structure, head-mounted display optical system, and head-mounted apparatus. The 2P-structured camera lens comprises a plano-convex first convex lens (L1) and a bi-convex second convex lens (L2) sequentially arranged in a reverse direction to a light incoming direction. The first convex lens (L1) comprises a first surface (S1) and a second surface (S2). The first surface (S1) is a planar surface near a diaphragm, and the diaphragm is located at a pupil of a human eye (11). The second surface (S2) is a non-spherical surface protruding toward an object side (12). The radius of curvature R1 of the first surface (S1) is equal to 0, and the radius of curvature R2 of the second surface (S2) is less than 0. The second convex lens (L2) comprises a third surface (S3) and a fourth surface (S4). The third surface (S3) and the fourth surface (S4) are non-spherical surfaces. The third surface (S3) is near the second surface (S2) of the first convex lens (L1) and protrudes toward the diaphragm. The fourth surface (S4) protrudes toward the object side (12). For the radius of curvature R3 of the third surface (S3) and the radius of curvature R4 of the fourth surface (S4), R3 < -R4. The present invention facilitates control and formation of a face of a single lens in a lens module, enables superior MTF and SPOT aberration correction, and provides a large field of view.

Description

2P structure lens, head-mounted display optical system and headwear

Technical field

The present invention relates to the field of eyepiece lens technology, and in particular to a 2P structure lens, a head mounted display optical system, and a headwear device.

Background of the invention

In recent years, with the advancement of the technology industry, 3D technology has been rapidly and widely developed. More and more movies and games are based on VR (Vatual Reality) technology to simulate real scenes, and the effects are realistic and shocking; As a new technology, head-mounted display has a good development prospect in the field of entertainment. It presents the two-dimensional image to the user in a more three-dimensional image, so that the user can have an immersive real feeling.

The eyepiece lens used in the existing VR device is limited to the imaging system of the small field of view, and the lens FOV (Field of View) is less than 100°. When the user observes the scene using the device, the boundary is felt and there is no obvious boundary. It satisfies the requirements of some high-end users in the game field to pursue the immersion of VR, and the user experience mainly depends on the angle of view of the eyepiece. Therefore, the eyepiece lens used in the existing VR device has a small angle of view and poor user experience. .

Summary of the invention

The invention provides a 2P (2pieces, two-piece) structure lens, a head-mounted display optical system and a head-wearing device to solve the problem that the angle of view of the lens of the imaging system adopting the small field of view is small and the user experience is not good.

According to an aspect of the present invention, a 2P structure lens is provided, including a first convex lens and a second convex lens which are sequentially disposed opposite to a light incident direction, the first convex lens is a plano-convex lens, and the second convex lens is a lenticular lens;

The first convex lens includes a first surface which is a plane close to the pupil, the pupil is located at the pupil of the human eye, and the second surface is an aspheric surface convex toward the object side; the radius of curvature R1 of the first surface is The radius of curvature R2 of the second surface satisfies the following relationship: R1=0, R2<0;

The second convex lens includes a third surface and a fourth surface, the third surface and the fourth surface are both aspherical surfaces, the third surface is adjacent to the second surface of the first convex lens and convex toward the pupil, and the fourth surface is convex toward the object side; The radius of curvature R3 of the three surfaces and the radius of curvature R4 of the fourth surface satisfy the following relationship: R3 < - R4.

According to another aspect of the present invention, there is provided a head mounted display optical system comprising, in order from a light incident direction, a diaphragm, a 2P structure lens according to an aspect of the present invention, and a display, light The 阑 is located at the pupil of the human eye and the display is located at the object side.

According to still another aspect of the present invention, there is provided a headgear device, such as a head-mounted display of another aspect of the present invention Optical system.

The beneficial effects of the present invention are: in the 2P structure lens of the present invention, first, the entire group of lenses includes two lenses, one of which is an aspherical plano-convex lens, and the other of which is an aspherical lenticular lens, and the first of the plano-convex lenses The radius of curvature R1 of the surface and the radius of curvature R2 of the second surface respectively satisfy the following relationship: R1=0, R2<0, and the radius of curvature R3 of the third surface on the lenticular lens and the radius of curvature R4 of the fourth surface satisfy the following relationship: R3<-R4, the 2P structure makes the face shape of the single lens of the lens module easier to control and shape, and the aberration correction of MTF (Modulation Transfer Function), SPOT (light spot) and the like is better, and at the same time, The large viewing angle of 120° can be used as a high-performance version of the head-mounted display eyepiece; secondly, its manufacturing cost and weight are greatly reduced.

In addition, the present invention also provides a head-mounted display optical system and a head-wearing device, which can not only meet the needs of a large angle of view VR, but also enable a user to obtain a better immersion feeling, thereby providing a better user experience. Improve the competitiveness of products.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic structural view of a 2P structure lens according to an embodiment of the present invention;

2 is an optical schematic diagram of an operation state of a 2P structure lens according to an embodiment of the present invention;

3 is a schematic diagram of an initial structure of a 2P structure lens according to an embodiment of the present invention;

4 is an optical structural diagram of a receiver of a 2P structure lens when it is offset from the optical axis by 0 mm according to an embodiment of the present invention;

FIG. 5 is a field curvature diagram of a 2P structure lens according to an embodiment of the present invention; FIG.

6 is a distortion diagram of a 2P structure lens according to an embodiment of the present invention;

7 is a dot-column diagram of a 2P structure lens according to an embodiment of the present invention;

FIG. 8 is a chromatic aberration diagram of a 2P structure lens according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic diagram of a receiver of a 2P structure lens deviating from the optical axis by −2 mm according to an embodiment of the present invention; FIG.

Figure 10 is a schematic illustration of a 2P structured lens receiver with a 2 mm offset from the optical axis, in accordance with one embodiment of the present invention.

detailed description

One prior art of an eyepiece lens for a VR device includes: a front group and a rear group in order along the incident direction of the light, the front group including a first negative lens and a second positive lens, and the rear group including a similar cemented lens group: a third positive lens and a fourth negative lens, the first negative lens having a first surface convex toward the object side and a second surface concave toward the image side, located at the beginning of the lens, the second positive lens having a third side of the concave object side a surface and a fourth surface convex toward the image side, the third positive lens having a fifth surface convex toward the object side and a sixth surface convex toward the image side, the fourth negative lens having a seventh surface and a concave direction of the concave object side Like the eighth surface of the square. However, this technology is mostly limited to small field of view imaging systems, and its lens FOV is small, and the user observes the device. In the scene, there will be obvious boundaries, which can not meet the immersive requirements of some high-end users in the game field, and the user experience mainly depends on the angle of view of the eyepiece. Therefore, the existing eyepiece lens for VR equipment There is a problem that the angle of view is small and the user experience is not good. At the same time, the structure is complicated, and the surface shape of the single lens of the lens module is not easy to be controlled, and the aberrations such as MTF and SPOT cannot be corrected, and the manufacturing cost is high. And the problem of heavy weight.

The design concept of the present invention is that the eyepiece lens for the existing VR device has a problem of small field of view and poor user experience, and at the same time, the structure is complicated, and the face shape of the lens module single lens is not easy to control. The lens can be corrected for MTF, SPOT, etc., the manufacturing cost is high, and the weight is large. The lens of the present invention uses two convex lenses, one of which is a plano-convex lens close to the pupil, and the other one is close to the object. a lenticular lens; the plane of the plano-convex lens near the pupil is a plane, and the radius of curvature R1=0, the surface of the plano-convex lens near the lenticular lens is aspherical, and the radius of curvature R2<0; both surfaces of the lenticular lens are aspherical, The radii of curvature of the two surfaces satisfy the following relationship: R3 < - R4. In this way, the technical solution of the present invention can not only meet the requirement of a large angle of view VR, but also obtain a large angle of view of 120°, so that the user can obtain a better immersion feeling, and at the same time, the surface shape of the lens module single lens is easy to control. Molding, better correction of aberrations such as MTF and SPOT, lower manufacturing cost and greatly reduced weight, can improve user experience and improve product competitiveness.

Embodiment 1

1 is an optical schematic diagram of an operation state of a 2P structure lens according to an embodiment of the present invention. Referring to FIG. 1, the 2P structure lens includes a first convex lens L1 and a second convex lens L2 which are sequentially disposed opposite to a light incident direction, first. The convex lens L1 is a plano-convex lens, and the second convex lens L2 is a lenticular lens;

The first convex lens L1 includes a first surface S1 which is a plane close to the pupil, a pupil located at a pupil of the human eye 11, and a second surface S2 which is an aspheric surface of the convex object 12; The radius of curvature R1 of the first surface S1 and the radius of curvature R2 of the second surface S2 respectively satisfy the following relationship: R1=0, R2<0;

The second convex lens L1 includes a third surface S3 and a fourth surface S4. The third surface S3 and the fourth surface S4 are both aspherical, and the third surface S3 is adjacent to the second surface S2 of the first convex lens L1 and convex toward the pupil. The four surface S4 is convex toward the object side 12; the radius of curvature R3 of the third surface S3 and the radius of curvature R4 of the fourth surface S4 satisfy the following relationship: R3 < - R4.

The structure diagram of the 2P structure lens shown in FIG. 1 and the optical principle diagram of the 2P structure lens shown in FIG. 2 show that the 2P structure lens in this embodiment is set as a display and the image on the display. The light is emitted, incident on the lens via the fourth surface S4 of the second convex lens L2, and then the lens is emitted from the first surface S1 of the first convex lens L1 to enter the image in the human eye 11, but the position of the image seen in the human eye 11 Not at the display position, but at the intersection of the inverse extension of the light entering the human eye from the first surface S1, that is, at the position of the imaging surface 13. In this way, the technical solution of the embodiment can not only meet the needs of the large viewing angle VR, but also enable the user to obtain a better immersion. At the same time, the correction of aberrations such as MTF and SPOT is better, which can improve the user experience and improve the competitiveness of the product.

Embodiment 2

In this embodiment, the focus of the two convex lenses of the 2P structure lens is mainly described. For other contents, refer to other embodiments of the present invention. A specific implementation of the 2P structure lens is as follows:

The focal length f1 of the first convex lens L1 and the focal length f2 of the second convex lens L2 satisfy the following relationship:

F2>10×f1.

It should be noted that, in this embodiment, the second convex lens L2 bears most of the power. In this way, the technical solution of the embodiment can make the structure of the lens more compact and reduce the overall volume of the lens, which is beneficial to the practical application and improvement of the user experience of the 2P structure lens of the present invention.

Embodiment 3

In the present embodiment, a further description will be focused on the focal length of the second convex lens L2 of the 2P structure lens, and other contents are referred to other embodiments of the present invention. A specific implementation of the 2P structure lens is as follows:

The focal length f1 of the first convex lens L1 and the focal length f2 of the second convex lens L2 further satisfy the following relationship:

100 mm < f2 < 150 mm, 12 mm < f1 < 14 mm.

It should be noted that, in this embodiment, the second convex lens L2 bears most of the optical power. Thus, the technical solution of the embodiment further improves the structure of the lens and reduces the overall volume of the lens. Moreover, the processing difficulty of the lens is minimized, thereby facilitating the practical application and improvement of the user experience of the 2P structure lens of the present invention, and is beneficial to reducing the cost and improving the yield.

Embodiment 4

In this embodiment, a further description is given on the radius of curvature of the two aspherical surfaces of the second convex lens L2 of the 2P structure lens, and other contents are referred to other embodiments of the present invention. A specific implementation of the 2P structure lens is as follows:

The radius of curvature R3 of the third surface of the second convex lens L2 and the radius of curvature R4 of the fourth surface further satisfy the following relationship:

R3>0, R4<0, -200mm<R3<-R4<200mm.

It should be noted that, in this embodiment, the second convex lens L2 further bears more power, and at the same time, the third surface S3 and the fourth surface S4 of the second convex lens L2 are more easily processed and corrected, so that the embodiment The technical solution further makes the structure of the lens more compact, reduces the overall volume of the lens, reduces the processing difficulty of the lens, improves the processing quality and the yield of the lens, thereby further improving the market competitiveness of the 2P structural lens of the present invention. .

Embodiment 5

In this embodiment, a further description is given of the materials and processes of the two convex lenses of the 2P structure lens. For other contents, refer to other embodiments of the present invention. A specific implementation of the 2P structure lens is as follows:

The first convex lens L1 and the second convex lens L2 are produced by using a COP (Cyclo-olefin polymer) optical plastic material and an injection molding process.

It should be noted that, in the present embodiment, the weight of the lens of the embodiment is greatly reduced when the COP optical plastic material is used instead of the glass material and other low-end PMMA (polymethyl methacrylate), PC (resin) or the like. And the plastic lens of the embodiment is produced by using an injection molding process, can be mass-produced, and has stable performance and low cost. Thus, the cost of the 2P structure lens of the present invention can be further reduced, and the competitiveness can be improved.

Embodiment 6

In this embodiment, further description is given to the respective surfaces of the two convex lenses of the 2P structure lens, and other contents are referred to other embodiments of the present invention. A specific implementation of the 2P structure lens is as follows:

The second surface S2 of the first convex lens L1, the third surface S3 and the fourth surface S4 of the second convex lens L2 both satisfy the following even aspheric equation formula:

[Correct according to Rule 91 20.03.2017]
Where z is the coordinate along the optical axis direction, Y is the radial coordinate in units of lens length units, c=1/R, c is the curvature, R is the radius of curvature, k is the conic coefficient (Coin Constant), αi is The coefficient of each higher order term, 2i is the order of Aspherical Coefficient, i=4.

It should be noted that, in this embodiment, the second surface S2 of the first convex lens L1 and the third surface S3 and the fourth surface S4 of the second convex lens L2 satisfy the above-described even-aspherical equation formula, and the quadratic term is up to 8th power.

The design of this embodiment is completed by ZEMAX optical design software, and the same design ideas can also be completed using CODEC optical design software. First, the initial structure is established as shown in Figure 3. Then, the evaluation function is built on the basis of the initial structure, and the design purpose is achieved by adding various operand constraints. The final optimization result is shown in Figure 1.

The design results of this embodiment are shown in Table 1. Table 1 lists the optical surface numbers (Surface) numbered sequentially by the object side 12, and the radius of curvature (R) of each optical surface on the optical axis. The distance (T) between the sides of the object side 12 to the optical axis of the image plane 13 of the image side and the latter optical surface, as shown in FIG. 4, T represents the fourth surface S4 of the second convex lens L2 to the rear side ( The distance of the object 12), the Coin Constant k, and the aspherical coefficients α1, α2, α3, and α4.

Table I

surfaceSurface	RR	TT	kk	α₁ α ₁	α₂ _{2 2}	α₃ _{3 3}	α₄ _{4 4}
L1-S1L1-S1	InfinityInfinity	12.676212.6762	0.000.00	0.000.00	0.000.00	0.000.00	0.000.00
L1-S2L1-S2	-30.3098-30.3098	1.99431.9943	-6.88E-01-6.88E-01	0.000.00	2.12E-062.12E-06	-3.41E-09-3.41E-09	-1.15E-12-1.15E-12
L2-S1L2-S1	111.2277111.2277	12.293212.2932	3.33E+003.33E+00	0.000.00	9.34E-079.34E-07	-5.11E-10-5.11E-10	-1.90E-13-1.90E-13
L2-S2L2-S2	-199.2492-199.2492	31.300031.3000	2.33E+012.33E+01	0.000.00	0.00E+000.00E+00	0.00E+000.00E+00	0.00E+000.00E+00

It can be seen that the 2P structure lens of the embodiment can better control the aberrations of the MTF, the distortion, the SPOT, etc., improve the imaging quality, and improve the user experience.

Example 7

In this embodiment, another description will be focused on the respective surfaces of the two convex lenses of the 2P structure lens. For other contents, refer to other embodiments of the present invention. A specific implementation of the 2P structure lens is as follows:

The second surface of the first convex lens, the third surface and the fourth surface of the second convex lens satisfy the following odd-order aspheric equation formula:

[Correct according to Rule 91 20.03.2017]
Where z is the coordinate along the optical axis direction, Y is the radial coordinate in units of lens length units, c=1/R, c is the curvature, R is the radius of curvature, k is the conic coefficient, and βi is the higher order term The coefficient of i is the aspherical higher power; i = 2N+1, N is a natural number, 1 ≤ N ≤ 8.

It should be noted that the design purpose can also be achieved by using the above-mentioned odd-order aspheric equation formula. In the 2P structure lens of this embodiment, the field curvature, distortion, dot map, and MTF can be sequentially referred to FIG. 5, FIG. 6, FIG. 7, and FIG. 8. The above figures are mainly for the reference wavelength green light (540 nm). analysis.

It can be seen from the above that the 2P structure lens of this embodiment has a field curvature of less than 10 mm, a distortion of less than 50%, and an RMS (root mean square) point of less than 0.3 mm. As shown in Fig. 9 and Fig. 10, respectively, when the human eye 11 at the pupil is a receiver, respectively, when the optical axis is -2 mm and 2 mm, the RMS point is less than 0.45 mm. The 2P structure lens can meet the needs of a large angle of view VR, can obtain a large angle of view of 120°, and has good optical parameter performance.

Example eight

Referring to FIG. 2, the head-mounted display optical system includes, in order from the incident direction of the light, a diaphragm, a 2P structure lens according to any one of Embodiments 1 to 7, and a display, the pupil being located in the human eye 11. Pupil, display Located at object side 12.

It should be noted that the head-mounted display optical system of this embodiment may further form a head-wearing device by providing a head-mounted fixing component, which may preferably be a fixed strap or a fixed helmet, etc., thereby facilitating operation and use by the user. Improve the user experience.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc. made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

A 2P structure lens includes a first convex lens and a second convex lens disposed in sequence against a light incident direction, wherein the first convex lens is a plano-convex lens, and the second convex lens is a lenticular lens;

The first convex lens includes a first surface that is a plane close to the pupil, the pupil is located at a pupil of the human eye, and the second surface is an aspheric surface that is convex toward the object side; The radius of curvature R1 of the first surface and the radius of curvature R2 of the second surface respectively satisfy the following relationship: R1=0, R2<0;

The second convex lens includes a third surface and a fourth surface, the third surface and the fourth surface are both aspherical, the third surface is adjacent to the second surface of the first convex lens and convex In the aperture, the fourth surface is convex toward the object side; the radius of curvature R3 of the third surface and the radius of curvature R4 of the fourth surface satisfy the following relationship: R3<-R4.
The 2P structure lens according to claim 1, wherein a focal length f1 of the first convex lens and a focal length f2 of the second convex lens satisfy a relationship of f2 > 10 × f1.
The 2P structure lens according to claim 2, wherein the focal length f1 of the first convex lens and the focal length f2 of the second convex lens further satisfy the following relationship:

100 mm < f2 < 150 mm, 12 mm < f1 < 14 mm.
The 2P structure lens according to claim 1, wherein the radius of curvature R3 of the third surface and the radius of curvature R4 of the fourth surface further satisfy the following relationship:

R3>0, R4<0, -200mm<R3<-R4<200mm.
The 2P structure lens according to claim 1, wherein the first convex lens and the second convex lens are produced by using a COP optical plastic material and an injection molding process.
[Correct according to Rule 91 20.03.2017]
The 2P structure lens according to any one of claims 1 to 5, wherein the second surface of the first convex lens, the third surface of the second convex lens, and the fourth surface Both satisfy the following even aspheric equation formula:

Where z is the coordinate along the optical axis direction, Y is the radial coordinate in units of lens length units, c=1/R, c is the curvature, R is the radius of curvature, k is the conic coefficient, and αi is the higher order term The coefficient of 2i is the aspherical high power, i=4.
[Correct according to Rule 91 20.03.2017]
The 2P structure lens according to any one of claims 1 to 5, wherein the second surface of the first convex lens, the third surface of the second convex lens, and the fourth surface The following odd-order aspheric equations are satisfied:

Where z is the coordinate along the optical axis direction, Y is the radial coordinate in units of lens length units, c=1/R, c is the curvature, R is the radius of curvature, k is the conic coefficient, and βi is the higher order term The coefficient of i is the aspherical higher power; i = 2N+1, N is a natural number, 1 ≤ N ≤ 8.
A head-mounted display optical system, characterized in that the head-mounted display optical system comprises, in order from the incident direction of the light, a diaphragm, a 2P structure lens according to any one of claims 1 to 7, and a display, The light pupil is located at the pupil of the human eye, and the display is located on the object side.
A head mounted device comprising the head mounted display optical system of claim 8.