Optical modules and head-mounted display devices

Abstract

This application provides an optical module and a head-mounted display device. The optical module includes, along the light transmission direction, a first lens group and a second lens group. The first lens group has positive optical power, and the second lens group has positive optical power. The first lens group includes at least two negative lenses, with at least one positive lens disposed 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 interval between the negative lenses is the interval between any two adjacent negative lenses. The second lens group includes at least one positive lens.

Description

Technical Field

[0001] This application relates to the field of near-eye display imaging technology, and more specifically, to an optical module and a head-mounted display device. Background Technology

[0002] In recent years, Augmented Reality (AR) and Virtual Reality (VR) technologies have been applied and rapidly developed in areas such as smart wearable devices. The core component of both AR and VR technologies is the optical module. The quality of the optical module's display directly determines the quality of the smart wearable device.

[0003] As application demands increase, such as users having different requirements for the portability and display quality of wearable devices, the size of displays is getting smaller and the resolution of imaging systems is getting higher and higher. This means that the requirements for the front-end optical system are getting higher and higher, especially when it is necessary to increase the standby time of the device, requiring the optical system to have small distortion and color difference.

[0004] Therefore, there is a need to provide a new type of optical module to solve the above-mentioned technical problems. Summary of the Invention

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

[0006] In a first aspect, this application provides an optical module. The optical module comprises, along the light transmission direction, a first lens group and a second lens group, wherein the optical power of the first lens group is positive, and the optical power of the second lens group is positive.

[0007] The first lens group 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 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 every 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 one of the at least two aspherical surfaces includes a curved surface.

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

[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 sequentially includes, along the light transmission direction: a first lens, a second lens, a third lens, and a fourth lens.

[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, along 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] Secondly, a head-mounted display device is provided. The head-mounted display device includes:

[0030] The shell, and

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

[0032] According to an embodiment of this application, an optical module is provided. The optical module includes a first lens group and a second lens group, both with positive optical power. The optical module reduces optical aberrations and improves optical imaging quality by introducing lenses with negative optical power. Furthermore, by defining the ratio between the sum of the optical power of the negative lenses and the sum of the intervals between the negative lenses, chromatic aberration can be effectively reduced.

[0033] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

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

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

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

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

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

[0039] Figure 5 for Figure 1 The transverse chromatic aberration diagram of the optical module is shown.

[0040] Figure 6 This is a second schematic diagram of the structure of the optical module provided in the embodiments of this application.

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

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

[0043] Figure 9 for Figure 6The field curvature distortion diagram of the optical module is shown.

[0044] Figure 10 for Figure 6 The transverse chromatic aberration diagram of the optical module is shown.

[0045] Figure 11 This is a second schematic diagram of the structure of the optical module provided in the embodiments of this application.

[0046] Figure 12 for Figure 11 The MTF curve of the optical module is shown.

[0047] Figure 13 for Figure 11 A schematic diagram of the dot array of the optical module is shown.

[0048] Figure 14 for Figure 11 The field curvature distortion diagram of the optical module is shown.

[0049] Figure 15 for Figure 11 The transverse chromatic aberration diagram of the optical module is shown.

[0050] Explanation of reference numerals in the attached figures:

[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. Monitor;

[0054] 4. The human eye. Detailed Implementation

[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, numerical expressions, and values ​​of the components and steps 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 and is in no way intended to limit the scope of this application and its application or use.

[0057] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

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

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

[0060] The following is in conjunction with the appendix Figures 1 to 15 The optical module and head-mounted display device provided in the embodiments of this application will be described in detail.

[0061] According to one aspect of the embodiments of this application, an optical module is provided, which is a direct-transmission optical structure design suitable for use in head-mounted display (HMD) devices. For example, VR head-mounted devices may include VR glasses or VR helmets, etc., and the embodiments of this application do not impose specific limitations on this.

[0062] This application provides an optical module. The optical module includes, along the light transmission direction, a first lens group 1 and a second lens group, wherein the optical power of the first lens group 1 is positive, and the optical power of the second lens group is positive.

[0063] 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 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 every two adjacent negative lenses;

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

[0065] In this embodiment, a direct-transmittance optical path architecture is provided to achieve near-eye display. Specifically, the optical module includes a first lens group 1 and a second lens group along the light transmission direction, as shown in the reference. Figure 1 , Figure 6 and Figure 11 The first lens group 1 is positioned further away from the human eye 4 than the second lens group. The first lens group 1 is positioned closer to the display 3 than the second lens group. The light emitted from the display 3 exits through the light-emitting surface of the display 3, is transmitted through the first lens group 1, and then through the second lens group before entering the human eye 4.

[0066] The optical module includes two lens groups, both with positive optical power. Specifically, the sum of the optical powers of the lenses in the first lens group 1 is positive, and the sum of the optical powers of the lenses in the second lens group is positive. In this embodiment, imaging and display are performed using two lens groups with positive optical 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. Therefore, the optical module includes lenses with negative optical power. By introducing lenses with negative optical power, optical aberrations are reduced and optical image quality is improved. Specifically, in the optical module, the number of lenses with negative optical power is greater than 1.

[0068] At least one positive lens is disposed between two negative lenses. This can also be understood as the optical power of adjacent lenses to the negative lens being positive. In this embodiment, by rationally allocating the optical power of the lenses in the optical module, chromatic aberration of the optical module can be effectively reduced, and optical image quality improved. In one example, the first lens group 1 includes three lenses, with optical powers of negative, positive, and negative along the light transmission direction. In another example, the first lens group 1 includes four lenses, where the optical powers of the four lenses can be positive, negative, positive, and negative along the light transmission direction; or negative, positive, positive, and negative; or negative, positive, negative, and positive. In yet another embodiment, the first lens group 1 includes five lenses, where the optical powers of the five lenses can be positive, negative, positive, negative, and positive along the light transmission direction, and the optical powers of the five lenses can also be other values. It should be noted that this embodiment does not impose excessive limitations on the number of lenses in the first lens group 1. The first lens group 1 only needs to satisfy the requirement of including at least two negative lenses, with at least one positive lens disposed between the at least two negative lenses.

[0069] Furthermore, 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. The interval between the negative lenses is the interval between every two adjacent negative lenses. For example, when the first lens group 1 includes five lenses, the optical power of the five lenses can be negative, positive, negative, positive, and negative along the direction of light transmission. The interval between the first lens and the third lens along the direction of light transmission is b1, and the interval between the third lens and the fifth lens is b2. In this example, the interval between every two adjacent negative lenses can be understood as the sum of b1 and b2.

[0070] The second lens group includes at least one lens with positive optical power. For example, the second lens group may also include two lenses with positive optical power, or even more lenses with positive optical power. Thus, when the optical power of a lens adjacent to the negative optical power lens in the first lens group 1 is negative, the inclusion of a positive optical power lens in the second lens group ensures that the optical power of the adjacent lenses in the first lens group 1 are all positive.

[0071] It should be noted that, in this embodiment of the application, the number of lenses in the second lens group is not limited. It is only required that the second lens group includes at least one lens with positive optical power. In this way, when the optical 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 optical power, it is ensured that the optical power of the adjacent lenses of the negative optical power lens in the first lens group 1 is positive.

[0072] It should also be noted that in the embodiments of this 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 optical power of the lenses included in the second lens group is positive, in order to make the optical power distribution of the lenses in the optical module more reasonable, the optical power of the optical module is balanced by the lens with negative optical power in the first lens group 1.

[0073] Therefore, in this embodiment of the application, the number of negative power lenses included in the optical module is >1, and the optical power of the adjacent lenses of the negative power lenses is positive, and the sum of the optical power of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01. Through this constraint condition, the chromatic aberration of the optical module can be effectively reduced, as well as the optical aberration can be reduced, and the optical image quality can be improved.

[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, combined with the characteristics that the number of negative optical power lenses included in the optical module is >1, the optical powers of adjacent lenses to the negative optical power lenses are all 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 one of the at least two aspherical surfaces includes a curved surface.

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

[0078] In one example, the optical module contains lenses in which one, two, or more lenses have aspherical optical surfaces, and in which at least one inverted surface is included.

[0079] In yet another example, the optical module contains lenses in which each lens contains two aspherical surfaces, and at least one of the two optical surfaces of each lens is a curved surface.

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

[0081] In this embodiment, the optical module includes multiple lenses, each with an effective surface. The ratio of the maximum outer diameter of the effective surface to the image circle of the optical module is ≥0.8. This reduces the radial dimension of the optical module, thereby reducing its size and making it more portable. Specifically, the ratio of the maximum outer diameter of the effective surface of the optical lens to the designed image circle is ≥0.8, which reduces the radial dimension of the module.

[0082] The area within which the image is sharp when the lens is focused is usually a circle, hence the name "image circle." Alternatively, it can be understood that various aberrations cause image quality to decrease towards the edges. Therefore, the image produced by a lens has good image quality only in the central region; this is called the "image circle."

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

[0084] In this embodiment, limiting the air gap between connected lenses in the optical module characterizes the curvature of adjacent surfaces of adjacent lenses, which can improve the imaging quality of the optical module. Furthermore, limiting the air gap between connected lenses in the optical module ensures that the sum of the optical powers of the negative lenses / the sum of the intervals between the negative lenses is ≤0.01.

[0085] In one embodiment, refer to Figure 1 , Figure 6 and Figure 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 rays along the light path. 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, there are at least two lenses with negative optical power and at least one lens with positive optical power. There is at least one lens with positive optical power between the at least two lenses with negative optical power.

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

[0088] In one specific embodiment, refer to Figure 1 , Figure 6 and Figure 11 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; and the optical power φ4 of the fourth lens 14 is -0.05 < φ4 < 0.05.

[0089] In this embodiment, the optical power of the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 is defined. For a single lens, the optical power of the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 can be positive, zero, or negative. However, in the same optical module, it is necessary to satisfy that the optical module includes at least two lenses with negative optical power and at least one lens with positive optical power, and the sum of the optical power of the negative lenses / the sum of the intervals between the negative lenses ≤ 0.01. Therefore, the optical power of the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 is selected within a defined range so that the optical module satisfies that it includes at least two lenses with negative optical power and at least one lens with positive optical power, and the sum of the optical power of the negative lenses / the sum of the intervals between the negative lenses ≤ 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; and the center thickness T4 of the fourth lens 14 is: 1mm≤T4≤6mm.

[0091] In this embodiment, the center thickness of the first lens 11, the second lens 12, the third lens 13 and the fourth lens 14 are defined, and the air gap between adjacent lenses is combined to limit the total optical length of the optical module. While ensuring imaging quality, the total optical length of the optical module is not too long, and the optical module is more portable.

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

[0093] In this embodiment, the second lens group includes two lenses, which transmit light along the optical path. 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: 1mm ≤ T5 ≤ 8mm; the central thickness T6 of the sixth lens 22 is: 1mm ≤ T6 ≤ 8mm.

[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 overall 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 within the range of 1.45 < n < 1.90, and the optical module includes six lenses, and the dispersion coefficient of each lens is within 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 of which are aspherical surfaces, and anti-reflection film layers are provided on the two aspherical surfaces. For example, the anti-reflection film layer can be adhered to the lens surface or the anti-reflection film layer can be plated on the lens surface.

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

[0103] Embodiment 1

[0104] This 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. A display 3 is provided on the side of the first lens 11 away from the second lens 12.

[0105] In this configuration, the surface of the first lens 11 furthest from the second lens 12 is concave, and the surface of the first lens 11 closest to the second lens 12 is convex. The surface of the second lens 12 furthest from the first lens 11 is concave, and the surface of the second lens 12 furthest from the first lens 11 is convex. The surface of the third lens 13 furthest from the second lens 12 is concave, and the surface of the third lens 13 furthest from the second lens 12 is convex. The surface of the fourth lens 14 furthest from the third lens 13 is concave, and the surface of the fourth lens 14 furthest from the third lens 13 is convex. The surface of the fifth lens 21 furthest from the fourth lens 14 is concave, and the surface of the sixth lens 22 furthest from the fifth lens 21 is flat.

[0106] 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 in the optical module provided in this embodiment are specifically shown in Table 1 below.

[0107] Table 1

[0108]

[0109] in Figure 2 This is an MTF curve diagram of the optical module provided in Embodiment 1 of this application. The MTF curve is a modulation transfer function graph, and the imaging sharpness of the optical module is characterized by the contrast of black and white line pairs. Figure 2 As shown, in Example 1, the MTF was >0.15 at 39 lp / mm, resulting in clear imaging.

[0110] Figure 3 This is a schematic diagram of a dot matrix pattern provided in Embodiment 1 of this application. A dot matrix pattern refers to the pattern formed by the dispersion of light rays emitted from a single point into a diffuse pattern within a certain range. This pattern is used to evaluate the imaging quality of the optical module. For example... Figure 3 As shown, in Example 1, the maximum value of the image point in the dot matrix image is less than 19μm, resulting in clear imaging.

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

[0112] Figure 5 This is the transverse chromatic aberration diagram provided in Embodiment 1 of this application. Transverse chromatic aberration, also known as magnification chromatic aberration, mainly refers to the difference in focal positions of blue and red light on the image plane when a single polychromatic principal ray from the object side is emitted as multiple rays due to dispersion in the refraction system. In Embodiment 1, as shown... Figure 5 As shown, the maximum chromatic difference of the optical module is less than 12μm.

[0113] Example 2

[0114] This 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. A display 3 is provided on the side of the first lens 11 away from the second lens 12.

[0115] In this configuration, the surface of the first lens 11 furthest from the second lens 12 is concave, and the surface of the first lens 11 closest to the second lens 12 is convex. The surface of the second lens 12 closest to the first lens 11 is concave, and the surface of the second lens 12 furthest from the first lens 11 is concave. The surface of the third lens 13 furthest from the second lens 12 is convex, and the surface of the third lens 13 furthest from the second lens 12 is convex. The surface of the fourth lens 14 furthest from the third lens 13 is concave, and the surface of the fourth lens 14 furthest from the third lens 13 is convex. The surface of the fifth lens 21 furthest from the fourth lens 14 is convex, and the surface of the fifth lens 21 furthest from the fourth lens 14 is flat. The surface of the sixth lens 22 furthest from the fifth lens 21 is convex, and the surface of the sixth lens 22 furthest from the fifth lens 21 is convex. The optical power order from the first lens 11 to the sixth lens 22 is: positive, negative, positive, negative, positive, positive.

[0116] 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 in the optical module provided in this embodiment 2 are specifically shown in Table 2 below.

[0117] Table 2

[0118]

[0119] in Figure 7This is an MTF curve diagram of the optical module provided in Embodiment 2 of this application. The MTF curve diagram is a modulation transfer function graph, and the imaging sharpness of the optical module is characterized by the contrast of black and white line pairs. Figure 7 As shown, in Example 2, the MTF was >0.15 at 39 lp / mm, resulting in clear imaging.

[0120] Figure 8 This is a schematic diagram of a dot matrix pattern provided in Embodiment 2 of this application. A dot matrix pattern refers to the pattern formed by the dispersion of light rays emitted from a single point into a diffuse pattern within a certain range. This pattern is used to evaluate the imaging quality of the optical module. For example... Figure 8 As shown in Example 2, the maximum value of the image point in the dot matrix image is less than 19μm, resulting in clear imaging.

[0121] Figure 9 This is the field curvature distortion diagram provided in Embodiment 2 of this application. The field curvature distortion diagram reflects the difference in the image plane position of the clear image in different fields of view. In Embodiment 2, the maximum absolute value of distortion is less than 7%.

[0122] Figure 10 This is the transverse chromatic aberration diagram provided in Embodiment 2 of this application. Transverse chromatic aberration, also known as magnification chromatic aberration, mainly refers to the difference in focal positions of blue and red light on the image plane when a single polychromatic principal ray from the object side is emitted as multiple rays due to dispersion in the refraction system. In Embodiment 2, as shown... Figure 10 As shown, the maximum chromatic difference of the optical module is less than 12μm.

[0123] Example 3

[0124] This application provides an optical module, such as Figure 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. A display 3 is provided on the side of the first lens 11 away from the second lens 12.

[0125] In this configuration, the surface of the first lens 11 furthest from the second lens 12 is concave, and the surface of the first lens 11 closest to the second lens 12 is convex. The surface of the second lens 12 furthest from the first lens 11 is concave, and the surface of the second lens 12 furthest from the first lens 11 is convex. The surface of the third lens 13 furthest from the second lens 12 is concave, and the surface of the third lens 13 furthest from the second lens 12 is convex. The surface of the fourth lens 14 furthest from the third lens 13 is concave, and the surface of the fourth lens 14 furthest from the third lens 13 is concave. The surface of the fifth lens 21 furthest from the fourth lens 14 is convex, and the surface of the sixth lens 22 furthest from the fifth lens 21 is flat.

[0126] 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 in the optical module provided in this embodiment 3 are specifically shown in Table 3 below.

[0127] Table 3

[0128]

[0129]

[0130] in Figure 12 This is an MTF curve diagram of the optical module provided in Embodiment 3 of this application. The MTF curve is a modulation transfer function graph, and the imaging sharpness of the optical module is characterized by the contrast of black and white line pairs. Figure 12 As shown, in Example 3, the MTF was >0.15 at 39 lp / mm, resulting in clear imaging.

[0131] Figure 13 This is a schematic diagram of a dot matrix provided in Embodiment 3 of this application. A dot matrix refers to a pattern formed by the dispersion of light rays emitted from a single point. After passing through an optical module, due to aberrations, the intersection points of these rays with the image plane are no longer concentrated at a single point, but rather form a diffuse pattern scattered over a certain range. This pattern can be used to evaluate the imaging quality of the optical module. For example... Figure 13 As shown, in Example 3, the maximum value of the image point in the dot matrix image is less than 19μm, resulting in clear imaging.

[0132] Figure 14 This is the field curvature distortion diagram provided in Embodiment 3 of this application. The field curvature distortion diagram reflects the difference in the position of the image plane that forms a clear image in different fields of view. In Embodiment 3, the maximum absolute value of the distortion is less than 7%.

[0133] Figure 15This is the transverse chromatic aberration diagram provided in Embodiment 3 of this application. Transverse chromatic aberration, also known as magnification chromatic aberration, mainly refers to the difference in focal positions of blue and red light on the image plane when a single polychromatic principal ray from the object side is emitted as multiple rays due to dispersion in the refraction system. In Embodiment 3, as shown... Figure 15 As shown, the maximum chromatic difference of the optical module is less than 12μm.

[0134] According to another aspect of the embodiments of this application, a head-mounted display device is also provided, the head-mounted display device including a housing and an optical module as described above. The head-mounted display device may be, for example, a VR head-mounted device, including VR glasses or a VR helmet, etc., and the embodiments of this application do not impose specific limitations on this.

[0135] The specific implementation of the head-mounted display device in this application can be referred to the above-described embodiments of the display module, and will not be repeated here.

[0136] The above embodiments mainly describe 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. For the sake of brevity, they will not be elaborated here.

[0137] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this 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) is positive, and the optical power of the second lens group (2) is 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; Wherein, 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); 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 (I3) is: -0.2 < φ3 < 0.1; The optical power φ4 of the fourth lens (14) is: -0.05 < φ4 < 0.05; 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 anti-curved 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, characterized in that, The minimum air gap between every two adjacent lenses in the optical module ≥ 0.1 mm.

6. The optical module according to claim 1, 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.

7. The optical module according to any one of claims 1-6, 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.

8. The optical module according to claim 7, 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.

9. The optical module according to claim 7, 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.

10. The optical module according to claim 1, characterized in that, 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.

11. 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.

12. A head-mounted display device, characterized in that, The head-mounted display device includes: A housing, and The optical module according to any one of claims 1-11.

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