Head-mounted display optical system and VR device

Abstract

The utility model discloses a head-mounted display optical system and VR equipment. The head-mounted display optical system comprises a receiving end, a first lens, a second lens, a third lens, a fourth lens and a display, the first lens, the second lens, the third lens and the fourth lens are sequentially arranged between the receiving end and the display along the direction from the receiving end to the display; the first lens is an aspherical lens which is convex towards the display and has positive focal power, the fourth lens is an aspherical lens which is convex towards the display and has negative focal power, and the second lens and the third lens are aspherical lenses with negative focal power. Compared with the prior art, through the arrangement of the lens group, more light can be introduced, a large field angle can be obtained, aberration can be effectively corrected, distortion can be reduced, the imaging quality can be improved, the weight and the size of the optical system can be reduced, the weight and the size of the VR can be reduced, and the use experience of a user can be improved while the compact structure of the optical system is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical technology field especially relates to a head-mounted display optical system and VR equipment. BACKGROUND

[0002] With the development of optical technology, the user's requirement to VR equipment is also higher and higher. In the design process of the existing VR equipment, it is required to improve the field of view while maintaining high resolution, but increasing the field of view will bring aberration to the head-mounted display optical system and increase the distortion of the head-mounted display optical system. In the prior art, the imaging quality problem is usually solved by increasing the lens amount, but increasing the lens amount will increase the complexity of the head-mounted display optical system, increase the volume and weight of the head-mounted display optical system, and thus affect the wearing experience of the VR equipment.

[0003] Therefore, it is necessary to provide a head-mounted display optical system and VR equipment to solve the above problems. SUMMARY

[0004] In view of the deficiencies in the prior art, the utility model provides a head-mounted display optical system and VR equipment, which can reduce the weight and volume of the optical system while improving the imaging quality of the optical system, so as to improve the user's experience.

[0005] To achieve the above purpose, the first aspect of the utility model provides a head-mounted display optical system, which comprises a receiving end, a first lens, a second lens, a third lens, a fourth lens and a display. The first lens, the second lens, the third lens and the fourth lens are sequentially arranged between the receiving end and the display along the direction from the receiving end to the display. The first lens is a convex display and a positive aspherical lens, the fourth lens is a convex display and a negative aspherical lens, and the second lens and the third lens are negative aspherical lenses.

[0006] In a preferred embodiment, the effective focal lengths of the first lens, the second lens, the third lens and the fourth lens are F1, F2, F3 and F4 respectively, and F1 is positive, and F2, F3 and F4 are negative.

[0007] In a preferred embodiment, the effective focal length of the head-mounted display optical system is F, and it satisfies: 0.566≤F1 / F≤0.931, -7.749≤F2 / F≤-5.435, -0.87≤F3 / F≤-0.585, -0.633≤F4 / F≤-1.097.

[0008] In a preferred embodiment, the refractive indexes of the first lens, the second lens, the third lens and the fourth lens at D line are N1, N2, N3 and N4 respectively, and satisfy: 1.52≤N1≤1.58, 1.49≤N2≤1.60, 1.62≤N3≤1.68, 1.60≤N4≤1.70.

[0009] In a preferred embodiment, the Abbe numbers of the first lens, the second lens, the third lens and the fourth lens at D line are V1, V2, V3 and V4 respectively, and satisfy: 41.5≤V1≤63.2, 45.4≤V2≤68.5, 20.4≤V3≤30, 19.3≤V4≤25.

[0010] In a preferred embodiment, the half field of view of the head-mounted display optical system is HFOV, and satisfies: 59°≤HFOV≤60°.

[0011] In a preferred embodiment, the radius of curvature of the first lens near the receiving end is R1, and the radius of curvature of the first lens away from the receiving end is R2; the radius of curvature of the second lens near the receiving end is R3, and the radius of curvature of the second lens away from the receiving end is R4; the radius of curvature of the third lens near the receiving end is R5, and the radius of curvature of the third lens away from the receiving end is R6; the radius of curvature of the fourth lens near the receiving end is R7, and the radius of curvature of the fourth lens away from the receiving end is R8, and satisfy: -930mm≤R1≤-730.6mm, -16.5mm≤R2≤-12.2mm, 310.3mm≤R3≤350.4mm, 82.4mm≤R4≤125mm, 41.3mm≤R5≤56.5mm, 9.3mm≤R6≤16.4mm, -24.1mm≤R7≤-28.2mm, -15.4mm≤R8≤-8.6mm.

[0012] In a preferred embodiment, the first lens, the second lens, the third lens and the fourth lens are all 10th order aspherical lenses.

[0013] In a preferred embodiment, the first lens, the second lens, the third lens and the fourth lens are all plastic lenses.

[0014] The second aspect of the utility model provides a kind of VR equipment, it includes the head-mounted display optical system in any one embodiment of preceding.

[0015] The head-mounted display optical system has the beneficial effects that: through the setting of the first lens, the second lens, the third lens and the fourth lens, the light trend of the head-mounted display optical system is gentle, more light can be introduced, the field of view range is increased, the aberration of the system is effectively corrected, the distortion is reduced, the imaging quality is improved, meanwhile, through the setting of the shape of the lens group, the weight and the volume of the head-mounted display optical system can be effectively reduced, the compactness of the optical system is improved, and the use experience of the VR equipment is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structure schematic diagram of the head-mounted display optical system provided by the utility model embodiment is shown in the figure.

[0017] Figure 2 A point list diagram of the head-mounted display optical system provided by the utility model embodiment is shown in the figure.

[0018] Figure 3 A field curvature distortion curve diagram of the head-mounted display optical system provided by the utility model embodiment is shown in the figure.

[0019] Figure 4 A transfer function curve diagram of the head-mounted display optical system provided by the utility model embodiment is shown in the figure. DETAILED DESCRIPTION

[0020] In the utility model, the terms "set", "provided with" and "connected" should be understood in a broad sense. For example, it can be fixed connection, detachable connection, or integral structure; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication between two devices, elements or components. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0021] The terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one feature. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0022] In addition, in addition to being used to represent the orientation or position relationship, the above-mentioned part of the terms can also be used to represent other meanings, for example, the term "upper" can also be used to represent a certain dependent relationship or connection relationship in some cases. For ordinary skilled in the art, the specific meaning of these terms in the utility model can be understood according to the specific circumstances.

[0023] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the following will make further detailed description to the utility model by combining with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model, and are not used to limit the utility model.

[0024] Specifically, the following is provided by the first aspect of the utility model:

[0025] Please refer to Figure 1 In the embodiment, the head-mounted display optical system includes a receiving end 1, a first lens 2, a second lens 3, a third lens 4, a fourth lens 5 and a display.

[0026] The display is an organic electroluminescent device or a transmissive liquid crystal display, which is used to emit imaging light. Specifically, the first lens 2, the second lens 3, the third lens 4 and the fourth lens 5 are sequentially arranged between the receiving end 1 and the display along the direction from the receiving end 1 to the display; the first lens 2 is a convex non-spherical lens with positive focal power, the fourth lens 5 is a convex non-spherical lens with negative focal power, and the second lens 3 and the third lens 4 are both non-spherical lenses with negative focal power.

[0027] By setting the first lens 2 with positive focal power, the light collection of the head-mounted display optical system is facilitated, and the field of view range of the head-mounted display optical system can be effectively increased; by setting the second lens 3 and the third lens 4 with negative focal power, the light rays can be projected relatively gently, more light rays can be introduced, and the structure of the head-mounted display optical system can be more compact and the volume can be relatively smaller; by setting the fourth lens 5 with negative focal power, the head-mounted display optical system can bear a larger focal power, change the propagation direction of the light rays, correct the aberration of the off-axis field of view, and be more conducive to the imaging of the light beam.

[0028] It can be understood that, by setting the first lens 2, the second lens 3, the third lens 4 and the fourth lens 5, the light rays of the head-mounted display optical system can be projected gently, more light rays can be introduced to increase the field of view range, the aberration of the system can be effectively corrected, the distortion can be reduced, and the imaging quality can be improved. At the same time, by setting the shape of the lens group, the weight and volume of the head-mounted display optical system can be effectively reduced, the compactness of the optical system can be improved, and the user's use experience can be improved.

[0029] Further, in one embodiment, the effective focal lengths of the first lens 2, the second lens 3, the third lens 4 and the fourth lens 5 are F1, F2, F3 and F4 respectively, and F1 is positive, and F2, F3 and F4 are all negative.

[0030] Specifically, the effective focal length of the head-mounted display optical system is F, and the following conditions are met: 0.566≤F1 / F≤0.931, -7.749≤F2 / F≤-5.435, -0.87≤F3 / F≤-0.585, and -0.633≤F4 / F≤-1.097.

[0031] Further, the refractive indexes of the first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 on the D line are N1, N2, N3, and N4 respectively, and the following conditions are met: 1.52≤N1≤1.58, 1.49≤N2≤1.60, 1.62≤N3≤1.68, and 1.60≤N4≤1.70.

[0032] The Abbe numbers of the first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 on the D line are V1, V2, V3, and V4 respectively, and the following conditions are met: 41.5≤V1≤63.2, 45.4≤V2≤68.5, 20.4≤V3≤30, and 19.3≤V4≤25.

[0033] The curvature radius of the first lens 2 close to the receiving end 1 is R1, and the curvature radius of the first lens 2 away from the receiving end 1 is R2; the curvature radius of the second lens 3 close to the receiving end 1 is R3, and the curvature radius of the second lens 3 away from the receiving end 1 is R4; the curvature radius of the third lens 4 close to the receiving end 1 is R5, and the curvature radius of the third lens 4 away from the receiving end 1 is R6; the curvature radius of the fourth lens 5 close to the receiving end 1 is R7, and the curvature radius of the fourth lens 5 away from the receiving end 1 is R8, and the following conditions are met: -930mm≤R1≤-730.6mm, -16.5mm≤R2≤-12.2mm, 310.3mm≤R3≤350.4mm, 82.4mm≤R4≤125mm, 41.3mm≤R5≤56.5mm, 9.3mm≤R6≤16.4mm, -24.1mm≤R7≤-28.2mm, and -15.4mm≤R8≤-8.6mm.

[0034] Further, the half field of view of the head-mounted display optical system is HFOV, and the following condition is met: 59°≤HFOV≤60°. The first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 are all 10th order aspherical lenses.

[0035] Specifically, the aspherical coefficients of the aspherical surfaces of the first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 all include a quadratic surface coefficient a1, a fourth-order aspherical coefficient a2, a sixth-order aspherical coefficient a3, an eighth-order aspherical coefficient a4, and a tenth-order aspherical coefficient a5.

[0036] Along the direction from the receiver 1 to the display, the surfaces of the first lens 2, the second lens 3, the third lens 4 and the fourth lens 5 are sequentially defined as surface number 1 to surface number 8. That is, the surface of the first lens 2 that is closer to the receiver 1 is surface number 1, and the surface of the fourth lens 5 that is closer to the display is surface number 8.

[0037] In a preferred embodiment, the aspherical coefficients of the surfaces of the first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 are shown in Table 1 below:

[0038] Surface No. [a1] [a2] [a3] [a4] a5 <!-- 3 -->]]> 1 187.915 -1.059E-005 -1.025E-008 2.771E-011 -1.560E-014 2 -3.116 -3.389E-005 3.4775E-008 -4.622E-011 -1.552E-015 3 50.457 -1.241E-006 -6.757E-009 6.3048E-012 -1.427E-015 4 -53.207 6.9780E-006 -1.860E-008 1.0268E-011 -1.591E-015 5 -13.202 -8.996E-006 4.927E-009 -4.2432E-014 -3.574E-016 6 -5.269 -1.062E-005 4.706E-009 -1.3669E-012 2.975E-016 7 -1.143 1.6766E-005 -8.712E-009 1.13695E-012 2.413E-016 8 -3.537 1.2522E-005 -5.068E-009 7.43945E-013 -1.582E-017

[0039] Table 1

[0040] It is understandable that by setting the parameters of the first lens 2, the second lens 3, the third lens 4 and the fourth lens 5, the aberrations of the system can be effectively corrected, distortion reduced, image quality improved, and the weight and volume of the head-mounted display optical system reduced, thereby improving the compactness of the optical system.

[0041] Furthermore, in one embodiment, the first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 are all plastic lenses. It is understood that using plastic lenses for the first lens 2, the second lens 3, the third lens 4, and the fourth lens 5 can further reduce the weight of the head-mounted display optical system, thereby reducing the burden on the user and improving the user experience.

[0042] For further details, please refer to... Figure 2 ,Should Figure 2 This is a dot plot of the optical system for head-mounted displays, by Figure 2 According to the information, the root mean square radius of the diffuse spot of the head-mounted display optical system is in the range of 14.572um to 37.501um, which is less than two pixels in size and can be accepted by the human eye.

[0043] Please refer to Figure 3 ,Should Figure 3 The field curvature and distortion curves of the head-mounted display optical system are shown below. Figure 3 According to the information, the field curvature of the head-mounted display optical system is less than 1.5mm, and the distortion value within the entire field of view does not exceed 22%, that is, the maximum distortion under a 120° diagonal field of view does not exceed 22%, which meets the design requirements for low distortion.

[0044] Please refer to Figure 4 ,Should Figure 4 The graph shows the transfer function of the optical system for a head-mounted display. Figure 4 The information shows that, in the full field of view, the transfer function value of the head-mounted display optical system is greater than 0.28 at 15 l p / mm, which increases the degree of freedom for optimization and meets the image quality requirements.

[0045] In summary, the head-mounted display optical system provided by the application can make the light ray trend of the head-mounted display optical system gentle, can introduce more light rays, can increase the field of view range, can effectively correct the aberration of the system, can reduce the distortion, and can improve the imaging quality.

[0046] The following is the content of the second aspect of the application:

[0047] The application provides a VR device, which comprises the head-mounted display optical system, the VR device has good processability, the weight and the volume of the VR device can be effectively reduced while relatively good imaging quality is obtained, and the use experience of a user can be effectively improved.

[0048] The above is merely a specific implementation manner of the application, and it should be noted that, for ordinary skilled persons in the technical field, some improvements and refinements can be made without departing from the principle of the application, and these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1. A head-mounted display optical system, characterized by, The head-mounted display optical system comprises a receiving end, a first lens, a second lens, a third lens, a fourth lens and a display.

2. The head-mounted display optical system of claim 1, wherein The effective focal lengths of the first lens, the second lens, the third lens and the fourth lens are F1, F2, F3 and F4 respectively, and F1 is positive, and F2, F3 and F4 are negative.

3. The head-mounted display optical system of claim 2, wherein, The effective focal length of the head-mounted display optical system is F, and 0.566≤F1 / F≤0.931, -7.749≤F2 / F≤-5.435, -0.87≤F3 / F≤-0.585 and -0.633≤F4 / F≤-1.097 are satisfied.

4. The head-mounted display optical system of claim 1, wherein, The refractive indexes of the first lens, the second lens, the third lens and the fourth lens at D line are N1, N2, N3 and N4 respectively, and 1.52≤N1≤1.58, 1.49≤N2≤1.60, 1.62≤N3≤1.68 and 1.60≤N4≤1.70 are satisfied.

5. The head-mounted display optical system of claim 1, wherein, The Abbe numbers of the first lens, the second lens, the third lens and the fourth lens at D line are V1, V2, V3 and V4 respectively, and 41.5≤V1≤63.2, 45.4≤V2≤68.5, 20.4≤V3≤30 and 19.3≤V4≤25 are satisfied.

6. The head-mounted display optical system of claim 1, wherein, The half field of view of the head-mounted display optical system is HFOV, and 59°≤HFOV≤60° is satisfied.

7. The head-mounted display optical system of Claim 1, wherein, The curvature radius of the surface of the first lens close to the receiving end is R1, and the curvature radius of the surface of the first lens away from the receiving end is R2; the curvature radius of the surface of the second lens close to the receiving end is R3, and the curvature radius of the surface of the second lens away from the receiving end is R4; the curvature radius of the surface of the third lens close to the receiving end is R5, and the curvature radius of the surface of the third lens away from the receiving end is R6; the curvature radius of the surface of the fourth lens close to the receiving end is R7, and the curvature radius of the surface of the fourth lens away from the receiving end is R8, and -930mm≤R1≤-730.6mm, -16.5mm≤R2≤-12.2mm, 310.3mm≤R3≤350.4mm, 82.4mm≤R4≤125mm, 41.3mm≤R5≤56.5mm, 9.3mm≤R6≤16.4mm, -24.1mm≤R7≤-28.2mm and -15.4mm≤R8≤-8.6mm are satisfied.

8. The head-mounted display optical system of claim 1, wherein, The first lens, the second lens, the third lens and the fourth lens are all 10th order aspherical lenses.

9. The head-mounted display optical system of claim 1, wherein, The first lens, the second lens, the third lens and the fourth lens are all plastic lenses.

10. A VR device, comprising: The head-mounted display optical system according to any one of preceding claims 1 to 9.

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