Optical module and head-mounted display device

Abstract

The embodiment of the invention provides an optical module and head-mounted display equipment. The optical module sequentially comprises a first lens group and a second lens group along the light transmission direction, the focal power of the first lens group is positive, and the focal power of the second lens group is positive; the first lens group comprises at least two negative lenses, and at least one positive lens is arranged between the two negative lenses; wherein the sum of the focal power of the negative lenses / the sum of the intervals between the negative lenses is smaller than or equal to 0.01, and the interval between the negative lenses is the interval between every two adjacent negative lenses; the second lens group includes at least one positive lens.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of near-eye display imaging technology, and more specifically, to an optical module and a head-mounted display device. Background Art

[0002] In recent years, augmented reality (AR) technology and virtual reality (VR) technology have been applied in smart wearable devices and have developed rapidly. The core components of augmented reality technology and virtual reality technology are both optical modules. The quality of the display effect of the optical module will directly determine the quality of the smart wearable device.

[0003] With the improvement of application requirements, for example, when users have different requirements for the portability and display quality of wearable devices, the size of the display is getting smaller and smaller, and the resolution of the imaging system is getting higher and higher. This means that the requirements for the front-end optical system are getting higher and higher, especially when the standby time of the device is to be increased, the optical system is required to have small distortion and chromatic aberration.

[0004] In view of this, it is necessary to provide a new optical module to solve the above technical problems. Summary of the invention

[0005] The purpose of this application is to provide a new technical solution for an optical module and a head-mounted display device.

[0006] In a first aspect, the present application provides an optical module. The optical module includes, in sequence along the light transmission direction: a first lens group and a second lens group, wherein the first lens group has a positive focal power, and the second lens group has a positive focal power;

[0007] The first lens group includes at least two negative lenses, and at least one positive lens is arranged between the two negative lenses; the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤ 0.01, and the intervals between the negative lenses are: the interval between two adjacent negative lenses;

[0008] The second lens group includes at least one positive lens.

[0009] Optionally, the sum of the optical powers of the negative lenses / the total optical power of the optical module is ≤0.2.

[0010] Optionally, the optical module includes at least two aspherical surfaces, and at least two of the aspherical surfaces include at least one anti-curved surface.

[0011] Optionally, the maximum outer diameter of the effective surface of the lens in the optical module / imaging circle is ≥0.8.

[0012] Optionally, the minimum air gap between every two adjacent lenses in the optical module is ≥ 0.1 mm.

[0013] Optionally, the first lens group includes, in the light transmission direction: a first lens, a second lens, a third lens, and a fourth lens in sequence.

[0014] Optionally, the optical power φ1 of the first lens is: -0.01 < φ1 < 0.07;

[0015] The optical power φ2 of the second lens is: -0.1 < φ2 < 0.1;

[0016] The optical power φ3 of the third lens is: -0.2 < φ3 < 0.1;

[0017] The optical power φ4 of the fourth lens is: -0.05 < φ4 < 0.05.

[0018] Optionally, the central thickness T1 of the first lens is: T1 ≥ 1.5 mm;

[0019] The central thickness T2 of the second lens is: 1 mm ≤ T2 ≤ 5 mm;

[0020] The central thickness T3 of the third lens is: 1 mm ≤ T3 ≤ 6 mm;

[0021] The central thickness T4 of the fourth lens is: 1 mm ≤ T4 ≤ 6 mm.

[0022] Optionally, the second lens group includes, in the light transmission direction: a fifth lens and a sixth lens, and both the fifth lens and the sixth lens are positive lenses.

[0023] Optionally, the optical power φ5 of the fifth lens is: 0 < φ5 < 0.04;

[0024] The optical power φ6 of the sixth lens is: 0 < φ6 < 0.04.

[0025] Optionally: the central thickness T5 of the fifth lens is: 1 mm ≤ T5 ≤ 8 mm;

[0026] The central thickness T6 of the sixth lens is: 1 mm ≤ T6 ≤ 8 mm.

[0027] Optionally, the refractive index of the lenses in the optical module is: 1.45 < n < 1.90, and the dispersion coefficient of the lenses in the optical module is: 20 < v < 75.

[0028] Optionally, an anti-reflection film layer is provided on the surfaces of the lenses in the optical module.

[0029] In a second aspect, a head mounted display device is provided. The head mounted display device comprises:

[0030] housing, and

[0031] An optical module as described in the first aspect.

[0032] According to an embodiment of the present application, an optical module is provided. The optical module includes a first lens group and a second lens group, both of which have positive optical powers. The optical module reduces optical aberrations and improves optical imaging quality by introducing lenses with negative optical powers, and limits the ratio between the sum of the optical powers of the negative lenses and the sum of the intervals between the negative lenses, which can effectively reduce optical chromatic aberrations.

[0033] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0035] Figure 1 This is one of the structural schematic diagrams of the optical module provided in the embodiment of the present application.

[0036] Figure 2 for Figure 1 MTF curve diagram of the optical module is shown.

[0037] Figure 3 for Figure 1 A schematic diagram of a dot array of an optical module is shown.

[0038] Figure 4 for Figure 1 Field curvature distortion diagram of the optical module shown.

[0039] Figure 5 for Figure 1 A diagram of vertical axis chromatic aberration of the optical module is shown.

[0040] Figure 6 This is a second structural schematic diagram of the optical module provided in an embodiment of the present application.

[0041] Figure 7 for Figure 6 MTF curve diagram of the optical module is shown.

[0042] Figure 8 for Figure 6 A schematic diagram of a dot array of an optical module is shown.

[0043] Fig. 9 for Figure 6Field curvature distortion diagram of the optical module shown.

[0044] Fig.10 for Figure 6 A diagram of vertical axis chromatic aberration of the optical module is shown.

[0045] Fig.11 This is a second structural schematic diagram of the optical module provided in an embodiment of the present application.

[0046] Fig.12 for Fig.11 MTF curve diagram of the optical module is shown.

[0047] Fig.13 for Fig.11 A schematic diagram of a dot array of an optical module is shown.

[0048] Fig.14 for Fig.11 Field curvature distortion diagram of the optical module shown.

[0049] Fig.15 for Fig.11 A diagram of vertical axis chromatic aberration of the optical module is shown.

[0050] Description of reference numerals:

[0051] 1. First lens group; 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens;

[0052] 2. Second lens group; 21. Fifth lens; 22. Sixth lens;

[0053] 3. Display;

[0054] 4. Human eye. DETAILED DESCRIPTION

[0055] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0056] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0057] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0058] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0059] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0060] The following is combined with Figures 1 to 15 The optical module and head-mounted display device provided in the embodiments of the present application are described in detail.

[0061] According to one aspect of an embodiment of the present application, an optical module is provided, wherein the optical module is a straight-through optical structure design, which can be suitable for use in a head mounted display (HMD). For example, a VR head mounted device may include VR glasses or a VR helmet, etc., and the embodiment of the present application does not specifically limit this.

[0062] The embodiment of the present application provides an optical module. The optical module includes, in sequence along the light transmission direction: a first lens group 1 and a second lens group, wherein the first lens group 1 has a positive focal power, and the second lens group has a positive focal power;

[0063] The first lens group 1 comprises at least two negative lenses, and at least one positive lens is arranged between the two negative lenses; the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤ 0.01, and the intervals between the negative lenses are: the interval between the two adjacent negative lenses;

[0064] The second lens group includes at least one positive lens.

[0065] In the embodiment of the present application, a straight-through optical path architecture is provided to realize near-eye display. Specifically, the optical module includes a first lens group 1 and a second lens group along the light transmission direction. Figure 1 , Figure 6 and Fig.11 , the first lens group 1 is arranged farther from the human eye 4 than the second lens group. The first lens group 1 is arranged closer to the display 3 than the second lens group. The light emitted from the display 3 is emitted from the light emitting surface of the display 3, is transmitted through the first lens group 1, and is transmitted through the second lens group before hitting the human eye 4.

[0066] The optical module includes two lens groups with positive focal powers, that is, the sum of the focal powers of the lenses included in the first lens group 1 is positive, and the sum of the focal powers of the lenses included in the second lens group is positive. In the embodiment of the present application, imaging display is performed through two lens groups with positive focal powers.

[0067] The first lens group 1 includes at least two negative lenses, for example, the first lens group 1 includes at least two lenses with negative optical power, so the optical module includes lenses with negative optical power, and the optical aberration is reduced and the optical image quality is improved by introducing lenses with negative optical power. Specifically, in the optical module, the number of lenses with negative optical power is greater than 1.

[0068] At least one positive lens is arranged between the two negative lenses, which can also be understood as that the focal power of the adjacent lenses with negative focal power is positive. The embodiment of the present application can effectively reduce the chromatic aberration of the optical module and improve the optical image quality by reasonably allocating the focal power of the lenses in the optical module. In one example, the first lens group 1 includes three lenses, and the focal power of the three lenses is negative, positive, and negative along the transmission direction of the light; in another example, the first lens group 1 includes four lenses, wherein the focal power of the four lenses along the transmission direction of the light can be positive, negative, positive, and negative; or the focal power of the four lenses can be negative, positive, positive, and negative; or the focal power of the four lenses can be negative, positive, negative, and positive. Or in another embodiment, the first lens group 1 includes five lenses, wherein the focal power of the five lenses along the transmission direction of the light can be positive, negative, positive, negative, and positive, and the focal power of the five lenses can also be other. It should be noted that the embodiment of the present application does not make too many restrictions on the number of the first lens group 1, and the first lens group 1 only needs to include at least two negative lenses, and at least one positive lens is arranged between at least two negative lenses.

[0069] In addition, in the first lens group 1, the sum of the optical power of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01, and the interval between the negative lenses is: the interval between each two adjacent negative lenses; for example, when the first lens group 1 includes five lenses, along the transmission direction of the light, the optical power of the five lenses can be negative, positive, negative, positive, and negative; wherein along the transmission direction of the light, the interval between the first lens and the third lens is b1, and the interval between the third lens and the fifth lens is b2. In this example, the interval between each two adjacent negative lenses can be understood to be the sum of b1 and b2.

[0070] The second lens group includes at least one lens with positive power, for example, the second lens group may also include two lenses with positive power, and the second lens group may also include more lenses with positive power. Thus, when the power of the lens adjacent to the second lens group in the first lens group 1 is negative, since the second lens group includes a lens with positive power, it is ensured that the power of the lens adjacent to the lens with negative power in the first lens group 1 is positive.

[0071] It should be noted that, in the embodiments of the present application, there is no limitation on the number of lenses in the second lens group, and it is only required that the second lens group includes at least one lens with positive power. Thus, when the power of the lens adjacent to the second lens group in the first lens group 1 is negative, since the second lens group includes a lens with positive power, it is ensured that the power of the lenses adjacent to the negative power lens in the first lens group 1 are all positive.

[0072] It should also be noted that in the embodiment of the present application, the second lens group includes one positive lens, or the second lens group includes two positive lenses, or the second lens group includes three positive lenses, etc. Since the focal lengths of the lenses included in the second lens group are all positive, in order to make the focal length distribution of the lenses in the optical module more reasonable, the focal length of the optical module is balanced by the lenses with negative focal lengths in the first lens group 1.

[0073] Therefore, in the embodiment of the present application, the number of negative optical power lenses included in the optical module is greater than 1, and the optical power of the lenses adjacent to the negative optical power lenses is positive, and the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01. This constraint condition can effectively reduce the chromatic aberration of the optical module, reduce optical aberrations, and improve optical image quality.

[0074] In one embodiment, the sum of the optical powers of the negative lenses / the total optical power of the optical module is ≤0.2.

[0075] In this embodiment, the sum of the optical powers of the negative lenses in the optical module and the total optical power of the optical module are limited to further reduce the chromatic aberration of the optical module. Specifically, when the ratio of the sum of the optical powers of the negative lenses in the optical module to the total optical power of the optical module is ≤0.2, the number of negative optical power lenses included in the optical module is greater than 1, the optical power of the adjacent lenses to the negative optical power lenses is positive, and the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01, the chromatic aberration of the optical module can be further effectively reduced.

[0076] In one embodiment, the optical module includes at least two aspherical surfaces, and at least two of the aspherical surfaces include at least one anti-curved surface.

[0077] In this embodiment, the optical module includes at least two aspherical surfaces, and the at least two aspherical surfaces include at least one anti-curved surface, which can effectively reduce the distortion of the optical module.

[0078] In one example, among the lenses included in the optical module, one or two or more lenses have optical surfaces that are all aspherical surfaces, and the aspherical surfaces include at least one anti-curved surface.

[0079] In another example, among the lenses included in the optical module, both optical surfaces included in each lens are aspherical surfaces, wherein at least one of the two optical surfaces of each lens is an anti-curved surface.

[0080] In one embodiment, the maximum outer diameter of the effective surface of the lens in the optical module / imaging circle is ≥ 0.8.

[0081] In this embodiment, the optical module includes a plurality of lenses, each of which has an effective surface, wherein the ratio of the maximum outer diameter of the plurality of effective surfaces to the imaging circle of the optical module is ≥0.8, which can reduce the radial dimension of the optical module, thereby reducing the volume of the optical module and making the optical module more portable. Specifically, the maximum outer diameter of the effective surface of the optical lens in the optical module / the designed imaging circle is ≥0.8, which can reduce the radial dimension of the module.

[0082] The range of the image clarity when the lens is focused to the imaging focal point is usually a circle, so it is called the imaging circle; or it can be understood that various aberrations will also make the image quality lower as it approaches the edge. Therefore, the image produced by a lens has good imaging quality only in the middle area, which is called the "imaging circle".

[0083] In one embodiment, the minimum air gap between every two adjacent lenses in the optical module is ≥0.1 mm.

[0084] In this embodiment, the air gap between the connected lenses in the optical module is defined to characterize the curvature of the adjacent surfaces of the adjacent lenses, which can improve the imaging quality of the optical module. And the air gap between the connected lenses in the optical module is defined so that the optical module satisfies the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses ≤ 0.01.

[0085] In one embodiment, referring to Figure 1 , Figure 6 and Fig.11 The first lens group 1 includes, in sequence along the light transmission direction: a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14.

[0086] In a specific example, the first lens group 1 includes four lenses that transmit light along the light, and the four lenses are a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14. Among the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14, at least two lenses with negative optical power and at least one lens with positive optical power are included, and at least one lens with positive optical power is provided between the at least two lenses with negative optical power.

[0087] It should be noted that the first lens group 1 may further include more lenses, for example, the first lens group 1 includes at least four lenses.

[0088] In a specific embodiment, referring to Figure 1 , Figure 6 and Fig.11 The focal power φ1 of the first lens 11 is: -0.01<φ1<0.07; the focal power φ2 of the second lens 12 is: -0.1<φ2<0.1; the focal power φ3 of the third lens 13 is: -0.2<φ3<0.1; the focal power φ4 of the fourth lens 14 is: -0.05<φ4<0.05.

[0089] In this embodiment, the optical powers of the first lens 11, the second lens 12, the third lens 13 and the fourth lens 14 are limited, wherein for a single lens, the optical powers of the first lens 11, the second lens 12, the third lens 13 and the fourth lens 14 may be positive, zero or negative; however, in the same optical module, it is required to satisfy that the optical module includes at least two lenses with negative optical powers, and at least one lens with positive optical power, and the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01. Therefore, the optical powers of the first lens 11, the second lens 12, the third lens 13 and the fourth lens 14 are selected within a limited range, so that the optical module satisfies that the optical module includes at least two lenses with negative optical powers, and at least one lens with positive optical power, and the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01.

[0090] In one embodiment, the center thickness T1 of the first lens 11 is: T1≥1.5mm; the center thickness T2 of the second lens 12 is: 1mm≤T2≤5mm; the center thickness T3 of the third lens 13 is: 1mm≤T3≤6mm; the center thickness T4 of the fourth lens 14 is: 1mm≤T4≤6mm.

[0091] In this embodiment, the center thicknesses of the first lens 11, the second lens 12, the third lens 13 and the fourth lens 14 are limited, and combined with the air spacing between adjacent lenses, the total optical length of the optical module can be limited. While ensuring the imaging quality, the total optical length of the optical module will not be too long, and the optical module is more portable.

[0092] In one embodiment, referring to Figure 1 , Figure 6 and Fig.11 The second lens group includes a fifth lens 21 and a sixth lens 22 along the light transmission direction, and both the fifth lens 21 and the sixth lens 22 are positive lenses.

[0093] In this embodiment, the second lens group includes two lenses. Along the direction of light transmission, the two lenses are the fifth lens 21 and the sixth lens 22. The optical powers of both the fifth lens 21 and the sixth lens 22 are positive, ensuring that the optical powers of the adjacent lenses to the negative optical power lens are positive, which can effectively reduce the chromatic aberration of the optical module.

[0094] In a specific embodiment, the optical power φ5 of the fifth lens 21 is: 0 < φ5 < 0.04; the optical power φ6 of the sixth lens 22 is: 0 < φ6 < 0.04.

[0095] In this embodiment, the optical powers of the fifth lens 21 and the sixth lens 22 are limited. The optical powers of the fifth lens 21 and the sixth lens 22 can be selected from 0 (excluding) to 0.04 (excluding), and the optical powers of the fifth lens 21 and the sixth lens 22 can be equal or unequal.

[0096] In a specific embodiment: the central thickness T5 of the fifth lens 21 is: 1 mm ≤ T5 ≤ 8 mm; the central thickness T6 of the sixth lens 22 is: 1 mm ≤ T6 ≤ 8 mm.

[0097] In this embodiment, the central thicknesses of the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 are limited, and combined with the air gaps between adjacent lenses, the total optical length of the optical module can be limited.

[0098] In one embodiment, the refractive index of the lenses in the optical module is: 1.45 < n < 1.90, and the dispersion coefficient of the lenses in the optical module is: 20 < v < 75.

[0099] In a specific embodiment, the optical module includes six lenses, and the refractive index of each lens is in the range of 1.45 < n < 1.90, and the optical module includes six lenses, and the dispersion coefficient of each lens is in the range of 20 < v < 75.

[0100] In one embodiment, an anti-reflection film layer is provided on the surface of the lens in the optical module.

[0101] In a specific embodiment, the optical module includes six lenses, each lens has two optical surfaces, both optical surfaces are aspherical, and an anti-reflection film layer is provided on the two aspherical surfaces. For example, the anti-reflection film layer can be attached to the lens surface or the anti-reflection film layer can be deposited on the lens surface.

[0102] The optical module provided by the embodiments of the present application is described below through three embodiments.

[0103] Embodiment 1

[0104] The present application provides an optical module, such as Figure 1 As shown, the optical module includes: a first lens group 1 and a second lens group, the first lens group 1 includes a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14 along the light transmission direction; the second lens group includes a fifth lens 21 and a sixth lens along the light transmission direction, and a display 3 is arranged on the side of the first lens 11 away from the second lens 12.

[0105] Among them, the surface of the first lens 11 away from the second lens 12 is a concave surface, and the surface of the first lens 11 close to the second lens 12 is a convex surface. The surface of the second lens 12 close to the first lens 11 is a concave surface, and the surface of the second lens 12 away from the first lens 11 is a convex surface. The surface of the third lens 13 close to the second lens 12 is a concave surface, and the surface of the third lens 13 away from the second lens 12 is a convex surface. The surface of the fourth lens 14 close to the third lens 13 is a concave surface, and the surface of the fourth lens 14 away from the third lens 13 is a convex surface. The surface of the fifth lens 21 close to the fourth lens 14 is a concave surface, and the surface of the fifth lens 21 away from the fourth lens 14 is a convex surface. The surface of the sixth lens 22 close to the fifth lens 21 is a convex surface, and the surface of the sixth lens 22 away from the fifth lens 21 is a plane.

[0106] In the optical module provided in this embodiment 1, the optical parameters of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 21 and the sixth lens 22 may be specifically as shown in Table 1 below.

[0107] Table 1

[0108]

[0109] in Figure 2 : is the MTF curve of the optical module provided in Example 1 of the present application. The MTF curve is a modulation transfer function diagram, which characterizes the imaging clarity of the optical module by the contrast of the black and white line pairs. Figure 2 As shown, in Example 1, the MTF is >0.15 at 39lp / mm, and the image is clear.

[0110] Figure 3 This is a schematic diagram of the spot diagram provided in Example 1 of the present application. The spot diagram refers to the point diagram of many light rays emitted from one point after passing through the optical module. Due to aberration, their intersection points with the image plane are no longer concentrated at the same point, but form a diffuse pattern scattered in a certain range, which can be used to evaluate the imaging quality of the optical module. Figure 3 As shown, in Example 1, the maximum value of the image point in the point array diagram is less than 19 μm, and the image is clear.

[0111] Figure 4It is a field curvature distortion diagram provided in Example 1 of the present application. The field curvature distortion diagram reflects the difference in image plane position of clear images in different fields of view. In Example 1, the maximum absolute value of the distortion is less than 7%.

[0112] Figure 5 is the vertical axis chromatic aberration diagram provided in Example 1 of the present application. The vertical axis chromatic aberration is also called magnification chromatic aberration, which mainly refers to the difference between the focal positions of blue light and red light on the image plane, when a complex main light on the object side is transformed into multiple light rays due to the dispersion of the refraction system when it is emitted on the image side. In Example 1, Figure 5 As shown, the maximum chromatic aberration value of the optical module is less than 12μm.

[0113] Example 2

[0114] The present application provides an optical module, such as Figure 6 As shown, the optical module includes: a first lens group 1 and a second lens group, the first lens group 1 includes a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14 along the light transmission direction; the second lens group includes a fifth lens 21 and a sixth lens along the light transmission direction, and a display 3 is arranged on the side of the first lens 11 away from the second lens 12.

[0115] Among them, the surface of the first lens 11 away from the second lens 12 is a concave surface, and the surface of the first lens 11 close to the second lens 12 is a convex surface. The surface of the second lens 12 close to the first lens 11 is a concave surface, and the surface of the second lens 12 away from the first lens 11 is a concave surface. The surface of the third lens 13 close to the second lens 12 is a convex surface, and the surface of the third lens 13 away from the second lens 12 is a convex surface. The surface of the fourth lens 14 close to the third lens 13 is a concave surface, and the surface of the fourth lens 14 away from the third lens 13 is a convex surface. The surface of the fifth lens 21 close to the fourth lens 14 is a convex surface, and the surface of the fifth lens 21 away from the fourth lens 14 is a plane. The surface of the sixth lens 22 close to the fifth lens 21 is a convex surface, and the surface of the sixth lens 22 away from the fifth lens 21 is a convex surface. The order of the optical power of the first lens 11 to the sixth lens 22 is: positive, negative, positive, negative, positive, positive.

[0116] In the optical module provided in this embodiment 2, the optical parameters of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 21 and the sixth lens 22 may be specifically shown in Table 2 below.

[0117] Table 2

[0118]

[0119] in Figure 7: is the MTF curve diagram of the optical module provided in Example 2 of the present application. The MTF curve diagram is a modulation transfer function diagram, which characterizes the imaging clarity of the optical module by the contrast of the black and white line pairs. Figure 7 As shown, in Example 2, the MTF is >0.15 at 39lp / mm, and the image is clear.

[0120] Figure 8 This is a schematic diagram of the spot diagram provided in Example 2 of the present application. The spot diagram refers to the point diagram of many light rays emitted from one point after passing through the optical module. Due to aberration, their intersection points with the image plane are no longer concentrated at the same point, but form a diffuse pattern scattered in a certain range, which can be used to evaluate the imaging quality of the optical module. Figure 8 As shown, in Example 2, the maximum value of the image point in the point diagram is less than 19 μm, and the image is clear.

[0121] Fig. 9 It is a field curvature distortion diagram provided in Example 2 of the present application. The field curvature distortion diagram reflects the difference in image plane position of clear images in different fields of view. In Example 2, the maximum absolute value of the distortion is less than 7%.

[0122] Fig.10 The vertical axis chromatic aberration diagram provided in Example 2 of the present application is also called magnification chromatic aberration, which mainly refers to the difference between the focal positions of blue light and red light on the image plane, which become multiple light rays when emitted from the image side due to the dispersion of the refraction system. Fig.10 As shown, the maximum chromatic aberration value of the optical module is less than 12μm.

[0123] Example 3

[0124] The present application provides an optical module, such as Fig.11 As shown, the optical module includes: a first lens group 1 and a second lens group, the first lens group 1 includes a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14 along the light transmission direction; the second lens group includes a fifth lens 21 and a sixth lens along the light transmission direction, and a display 3 is arranged on the side of the first lens 11 away from the second lens 12.

[0125] Among them, the surface of the first lens 11 away from the second lens 12 is a concave surface, and the surface of the first lens 11 close to the second lens 12 is a convex surface. The surface of the second lens 12 close to the first lens 11 is a concave surface, and the surface of the second lens 12 away from the first lens 11 is a convex surface. The surface of the third lens 13 close to the second lens 12 is a concave surface, and the surface of the third lens 13 away from the second lens 12 is a convex surface. The surface of the fourth lens 14 close to the third lens 13 is a concave surface, and the surface of the fourth lens 14 away from the third lens 13 is a concave surface. The surface of the fifth lens 21 close to the fourth lens 14 is a convex surface, and the surface of the fifth lens 21 away from the fourth lens 14 is a convex surface. The surface of the sixth lens 22 close to the fifth lens 21 is a convex surface, and the surface of the sixth lens 22 away from the fifth lens 21 is a plane.

[0126] In the optical module provided in this embodiment 3, the optical parameters of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 21 and the sixth lens 22 may be specifically as shown in Table 3 below.

[0127] Table 3

[0128]

[0129]

[0130] in Fig.12 : is the MTF curve diagram of the optical module provided in Example 3 of the present application. The MTF curve diagram is a modulation transfer function diagram, which characterizes the imaging clarity of the optical module by the contrast of the black and white line pairs. Fig.12 As shown, in Example 3, the MTF is >0.15 at 39lp / mm, and the image is clear.

[0131] Fig.13 This is a schematic diagram of the spot diagram provided in Example 3 of the present application. The spot diagram refers to the point diagram of many light rays emitted from one point after passing through the optical module. Due to aberration, their intersection points with the image plane are no longer concentrated at the same point, but form a diffuse pattern scattered in a certain range, which can be used to evaluate the imaging quality of the optical module. Fig.13 As shown, in Example 3, the maximum value of the image point in the point array diagram is less than 19 μm, and the image is clear.

[0132] Fig.14 It is a field curvature distortion diagram provided in Example 3 of the present application. The field curvature distortion diagram reflects the difference in image plane position of clear images in different fields of view. In Example 3, the maximum absolute value of the distortion is less than 7%.

[0133] Fig.15is the vertical axis chromatic aberration diagram provided in Example 3 of the present application. The vertical axis chromatic aberration is also called magnification chromatic aberration, which mainly refers to the difference between the focal positions of blue light and red light on the image plane, when a complex main light on the object side is transformed into multiple light rays due to the dispersion of the refraction system when it is emitted on the image side. Fig.15 As shown, the maximum chromatic aberration value of the optical module is less than 12μm.

[0134] According to another aspect of the embodiment of the present application, a head mounted display device is also provided, the head mounted display device comprising a housing and the optical module as described above. The head mounted display device is, for example, a VR head mounted device, including VR glasses or a VR helmet, etc., and the embodiment of the present application does not specifically limit this.

[0135] The specific implementation of the head mounted display device of the embodiment of the present application can refer to the above-mentioned display module embodiments, which will not be repeated here.

[0136] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0137] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An optical module, characterized in that: The optical module sequentially includes, along the light transmission direction: a first lens group (1) and a second lens group (2), the optical power of the first lens group (1) being positive, and the optical power of the second lens group (2) being positive; The first lens group (1) includes at least two negative lenses, and at least one positive lens is disposed between the two negative lenses; wherein the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses ≤ 0.01, and the interval between the negative lenses is: the interval between every two adjacent negative lenses; The second lens group (2) includes at least one positive lens.

2. The optical module according to claim 1, characterized in that: The sum of the optical powers of the negative lenses / the total optical power of the optical module ≤ 0.

2.

3. The optical module according to claim 1, characterized in that: The optical module includes at least two aspherical surfaces, and at least one of the at least two aspherical surfaces is an anamorphic surface.

4. The optical module according to claim 1, wherein the maximum outer diameter of the effective surface of the lens in the optical module / the imaging circle ≥ 0.

8.

5. The optical module according to claim 1, wherein: The minimum air gap between every two adjacent lenses in the optical module ≥ 0.1 mm.

6. The optical module according to claim 1, characterized in that: The first lens group (1) sequentially includes, along the light transmission direction: a first lens (11), a second lens (12), a third lens (13), and a fourth lens (14).

7. The optical module according to claim 6, wherein The optical power φ1 of the first lens (11) is: -0.01 < φ1 < 0.07; The optical power φ2 of the second lens (12) is: -0.1 < φ2 < 0.1; The optical power φ3 of the third lens (13) is: -0.2 < φ3 < 0.1; The optical power φ4 of the fourth lens (14) is: -0.05 < φ4 < 0.

05.

8. The optical module according to claim 6, wherein The central thickness T1 of the first lens (11) is: T1 ≥ 1.5 mm; The central thickness T2 of the second lens (12) is: 1 mm ≤ T2 ≤ 5 mm; The central thickness T3 of the third lens (13) is: 1 mm ≤ T3 ≤ 6 mm; The central thickness T4 of the fourth lens (14) is: 1 mm ≤ T4 ≤ 6 mm.

9. The optical module according to any one of claims 1 to 8, characterized in that: The second lens group (2) includes, along the light transmission direction: a fifth lens (21) and a sixth lens (22), and both the fifth lens (21) and the sixth lens (22) are positive lenses.

10. The optical module according to claim 9, wherein The optical power φ5 of the fifth lens (21) is: 0 < φ5 < 0.04; The optical power φ6 of the sixth lens (22) is: 0 < φ6 < 0.

04.

11. The optical module according to claim 9, wherein: The central thickness T5 of the fifth lens (21) is: 1 mm ≤ T5 ≤ 8 mm; The central thickness T6 of the sixth lens (22) is: 1 mm ≤ T6 ≤ 8 mm.

12. The optical module according to claim 1, wherein: The refractive index of the lens in the optical module is: 1.45 < n < 1.90, and the dispersion coefficient of the lens in the optical module is: 20 < v < 75.

13. The optical module according to claim 1, characterized in that: An anti-reflection film layer is provided on the surface of the lens in the optical module.

14. A head mounted display device, characterized in that: The head-mounted display device includes: a housing, and An optical module as claimed in any one of claims 1 to 13.

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