Projection lens, ray machine and near-to-eye display equipment

Abstract

The invention is suitable for the technical field of micro projection display, and discloses a projection lens, an optical machine and a near-to-eye display device.The projection lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, the diaphragm, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the image source are sequentially arranged from the object side to the image side. The first lens, the second lens, the fourth lens and the fifth lens all have positive focal power; the third lens has negative focal power; the object side surface of the first lens is a convex surface, the object side surface of the second lens is a convex surface, the image side surface of the third lens is a concave surface, and the image side surface of the fifth lens is an M-shaped curved surface. According to the embodiment of the invention, the uniformity of the virtual image projected by the near-eye display equipment can be improved.

Description

Technical Field

[0001] The present invention relates to the field of micro-projection display technology, and in particular to a projection lens, an optical machine and a near-eye display device. Background Art

[0002] Near-eye display devices such as AR (Augmented Reality) and VR (Virtual Reality) devices include an optical machine and an optical waveguide. The optical machine is used to generate a specific image and emit a corresponding light signal, and the optical waveguide is used to transmit the light signal emitted by the optical machine in a directed manner to the human eye for normal imaging, thereby realizing a near-eye display.

[0003] However, the image projected by the current optical machine lens has low uniformity, which affects the brightness distribution of the image and the viewing experience; moreover, the performance of various projection parameters of the optical machine lens is not high, which affects the image quality. Summary of the invention

[0004] The first object of the present invention is to provide a projection lens, which aims to solve the technical problem of low uniformity of the image projected by the optical machine lens.

[0005] To achieve the above object, the solution provided by the present invention is:

[0006] A projection lens is applied to an optical machine, the optical machine includes an aperture and an image source, the projection lens includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens, and along the optical axis direction, the aperture, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the image source are arranged in sequence from the object side to the image side;

[0007] The first lens, the second lens, the fourth lens and the fifth lens all have positive optical power; the third lens has negative optical power;

[0008] The object side surface of the first lens is a convex surface, the object side surface of the second lens is a convex surface, the image side surface of the third lens is a concave surface, and the image side surface of the fifth lens is an M-shaped curved surface.

[0009] The second object of the present invention is to provide an optical machine, comprising an aperture, an image source and the above-mentioned projection lens.

[0010] The third object of the present invention is to provide a near-eye display device, which includes an optical waveguide and the above-mentioned optical machine, wherein the optical waveguide is arranged on the side of the aperture away from the first lens, and is used to receive the light beam emitted by the image source and transmit the light beam to the human eye for near-eye display.

[0011] The projection lens provided by the present invention has the following beneficial effects:

[0012] In the projection lens of this embodiment, the first lens, the second lens, the third lens, the fourth lens and the fifth lens combination can modulate the light to control the angles between the lens main light and the edge light and the optical axis to be limited within a certain range, and this range is determined by the light intensity distribution curve of the image source. Specifically, the angle range in which the light intensity drops to 90% compared to the central light intensity can be selected to make the light intensity received at each field of view angle of the projection lens close, so that the brightness distribution from the center to the edge of the virtual image projected by the projection lens is uniform, thereby improving the uniformity of the virtual image projected by the projection lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0014] Figure 1 is a structural schematic diagram of an optical machine provided by an embodiment of the present invention;

[0015] Figure 2 yes Figure 1 Schematic diagram of the optical path of the optical machine shown;

[0016] Figure 3 is another structural schematic diagram of an optical machine provided by an embodiment of the present invention;

[0017] Figure 4 is a light intensity distribution curve diagram of an image source in an embodiment provided by an embodiment of the present invention;

[0018] Figure 5 is a light receiving angle curve diagram of the projection lens in Example 1 provided by an embodiment of the present invention;

[0019] Figure 6 1 is a schematic diagram of uniformity simulation of a projection lens in Embodiment 1 provided by an embodiment of the present invention;

[0020] Figure 7 is a modulation transfer function curve diagram of the projection lens in Embodiment 1 provided by an embodiment of the present invention;

[0021] Figure 8 is a defocus curve diagram of the projection lens in Embodiment 1 provided by an embodiment of the present invention;

[0022] Fig. 9 is a diagram of optical distortion and astigmatism field curvature of the projection lens in Embodiment 1 provided by an embodiment of the present invention;

[0023] Fig.10 is a TV distortion diagram of the projection lens in Embodiment 1 provided by an embodiment of the present invention;

[0024] Fig.11 is an axial chromatic aberration curve diagram of the projection lens in Embodiment 1 provided by the embodiment of the present invention;

[0025] Fig.12 is a vertical axis chromatic aberration curve diagram of the projection lens in Example 1 provided by an embodiment of the present invention;

[0026] Fig.13 This is a thermal drift defocus curve diagram of the optical machine at -10° in Example 1 provided by the embodiment of the present invention;

[0027] Fig.14 This is a thermal drift defocus curve diagram of the optical machine at 20° in Example 1 provided by the embodiment of the present invention;

[0028] Fig.15 This is a thermal drift defocus curve diagram of the optical machine at 50° in Example 1 provided by the embodiment of the present invention;

[0029] Fig.16 is a light receiving angle curve diagram of the projection lens in Embodiment 2 provided by the embodiment of the present invention;

[0030] Fig.17 is a schematic diagram of uniformity simulation of a projection lens in Embodiment 2 provided by an embodiment of the present invention;

[0031] Fig.18 is a modulation transfer function curve diagram of the projection lens in Embodiment 2 provided by an embodiment of the present invention;

[0032] Fig.19 is a defocus curve diagram of the projection lens in Embodiment 2 provided by an embodiment of the present invention;

[0033] Fig. 20 is a diagram of optical distortion and astigmatism field curvature of the projection lens in Embodiment 2 provided by an embodiment of the present invention;

[0034] Fig.21 is a TV distortion diagram of the projection lens in Embodiment 2 provided by an embodiment of the present invention;

[0035] Fig. 22 is an axial chromatic aberration curve diagram of the projection lens in Embodiment 2 provided by an embodiment of the present invention;

[0036] Fig.23 is a vertical axis chromatic aberration curve diagram of the projection lens in Example 2 provided by an embodiment of the present invention;

[0037] Fig.24This is a thermal drift defocus curve diagram of the optical engine at -10° in Example 2 provided by the embodiment of the present invention;

[0038] Fig.25 This is a thermal drift defocus curve diagram of the optical machine at 20° in Example 2 provided by the embodiment of the present invention;

[0039] Fig.26 This is a thermal drift defocus curve diagram of the optical machine at 50° in Example 2 provided in an embodiment of the present invention.

[0040] Description of Figure Numbers:

[0041] 100, aperture; 200, image source; 10, first lens; 20, second lens; 30, third lens; 40, fourth lens; 50, fifth lens. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0044] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or may be indirectly connected to the other element through an intermediate element.

[0045] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] At present, the display module of the near-eye display device includes an optical machine and an optical waveguide, and the optical machine is used to input image information into the optical waveguide. In the related technology, the brightness uniformity of the image projected by the optical machine lens is low, which is difficult to make up for the extremely low uniformity of the optical waveguide, resulting in low uniformity of the display module entering the eye, affecting the human eye viewing experience; at the same time, the parameters of the optical machine lens such as MTF (modulation transfer function), distortion, light efficiency, thermal drift, etc. are still at a low level. After the performance loss of the optical waveguide, it cannot meet the high-standard imaging quality requirements.

[0047] like Figure 1 As shown, based on this, the embodiments of the present application provide a projection lens, an optical machine and a near-eye display device. The projection lens can be a MicroLED lens, which is not specifically limited in this embodiment. It is applied to the optical machine of the near-eye display device. As the lens of the optical machine, the optical machine can be a monochrome optical machine or a color optical machine. Furthermore, along the optical axis direction, the projection lens is arranged between the aperture 100 of the optical machine and the image source 200. The projection lens is adapted to the image source 200. The image source 200 can be a display screen using self-luminous display technology, such as a MicroLED display screen, which is not specifically limited in this embodiment.

[0048] Specifically, the projection lens sets a first lens 10, a second lens 20, a third lens 30, a fourth lens 40 and a fifth lens 50 according to the light intensity distribution curve of the image source 200, without significantly increasing the volume of the optical machine, and optimizes each optical lens to limit the angles between the main light ray and the edge light ray of the lens and the optical axis to a certain range, so that the light intensity received by each field of view angle of the projection lens is close, so that the brightness distribution from the center to the edge of the virtual image projected by the projection lens is uniform, thereby improving the uniformity of the virtual image projected by the projection lens.

[0049] The following is combined with Figure 1 To Attachment Fig.26 , some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0050] like Figure 1 As shown, the projection lens provided in this embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40 and a fifth lens 50. Along the optical axis direction, the aperture 100, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50 and the image source 200 are arranged in sequence from the object side (i.e., the imaging side) to the image side (i.e., the image source side). Specifically, in combination with Figure 1 The object side surface of the first lens 10 can be spaced apart from the light aperture of the aperture 100. Figure 3The object side surface of the first lens 10 may also be provided with a light hole protruding from the aperture 100, which is not specifically limited in this embodiment; the first lens 10, the second lens 20, the fourth lens 40 and the fifth lens 50 all have positive focal power; the third lens 30 has negative focal power, the first lens 10, the second lens 20, the fourth lens and the fifth lens 50 all have a converging effect on light, and the third lens 30 has a diverging effect on light.

[0051] Further, the object side surface of the first lens 10 is a convex surface, the object side surface of the second lens 20 is a convex surface, the image side surface of the third lens 30 is a concave surface, and the image side surface of the fifth lens 50 is an M-shaped curved surface. It can be understood that the object side surface of the first lens 10 is convex in the direction away from the image source 200, the object side surface of the second lens 20 is convex in the direction away from the image source 200, and the image side surface of the third lens 30 is concave in the direction away from the image source 200. Among them, along the optical axis direction, the image side surface is the side facing the image source 200, and the object side surface is the side away from the image source 200.

[0052] In this embodiment, combined with Figure 2 , the light emitted by the image source 200 can sequentially transmit the fifth lens 50, the fourth lens 40, the third lens 30, the second lens 20 and the first lens 10. The combination of the five lenses can modulate the light to reduce the angle between the light emitted by the image source 200 and the optical axis, so as to control the angles between the main light and the edge light of the lens and the optical axis to be limited within a certain range. This range is determined by the light intensity distribution curve of the image source 200. Specifically, the angle range in which the light intensity drops to 90% compared to the central light intensity can be selected, so that the light intensity received by each field of view angle of the projection lens is close, so that the light intensity received by each position from the center to the edge of the virtual image screen projected by the projection lens adapted to the image source 200 is close, and then the brightness distribution from the center to the edge of the virtual image screen projected by the projection lens is uniform, thereby improving the uniformity of the virtual image screen projected by the projection lens.

[0053] like Figure 1 As shown, in some embodiments, the image side surface of the first lens 10 is a convex surface, that is, the image side surface of the first lens 10 protrudes in the direction close to the image source 200, which is beneficial to control the angles between the main light and the edge light of the lens and the optical axis within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0054] like Figure 1 As shown, in some embodiments, the image side surface of the second lens 20 is a convex surface, that is, the image side surface of the second lens 20 protrudes in the direction close to the image source 200, which is beneficial to control the angles between the main light and the edge light of the lens and the optical axis within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0055] like Figure 1 As shown, in some embodiments, the object side surface of the third lens 30 is a convex surface, that is, the object side surface of the third lens 30 protrudes in a direction away from the image source 200, which is beneficial for controlling the angles between the main light and the marginal light of the lens and the optical axis to be within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0056] like Figure 1 As shown, in some embodiments, the object side surface of the fourth lens 40 is a concave surface, and the image side surface of the fourth lens 40 is a convex surface, that is, the object side surface of the fourth lens 40 is concave in the direction away from the aperture 100, and the image side surface of the fourth lens 40 is convex in the direction close to the image source 200; in other embodiments, the object side surface of the fourth lens 40 is a convex surface, and the image side surface of the fourth lens 40 is a concave surface, that is, the object side surface of the fourth lens 40 is convex in the direction away from the image source 200, and the image side surface of the fourth lens 40 is concave in the direction away from the image source 200. The above design is conducive to controlling the angles between the main light and the marginal light of the lens and the optical axis within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0057] like Figure 1 As shown, in some embodiments, the object side surface of the fifth lens 50 is a convex surface, that is, the object side surface of the fifth lens 50 protrudes in a direction away from the image source 200. In other embodiments, the object side surface of the fifth lens 50 is an M-shaped curved surface. The above design is conducive to controlling the angles between the main light and the marginal light of the lens and the optical axis within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0058] like Figure 1 As shown, in a specific embodiment, the image side surface of the fifth lens 50 includes a middle area (not shown) and an edge area (not shown), the edge area is arranged around the periphery of the middle area, the middle area is concave in the direction away from the image source 200, and the edge area is convex in the direction close to the image source 200.

[0059] Combination Figure 1 In some embodiments, the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 are all plastic lenses, and the fifth lens 50 is a glass lens, which is beneficial to improving the uniformity of the virtual image projected by the projection lens.

[0060] Combination Figure 1 In some embodiments, the field of view angle of the projection lens in the diagonal direction is FOV, and the projection lens satisfies: 20°≤FOV≤35°. For example, in the embodiment of the present application, FOV is set to 25°, 28° or 30°.

[0061] Combination Figure 1 In some embodiments, the diameter of the light hole of the aperture 100 is EPD, and the projection lens satisfies: 3mm≤EPD≤5.5mm.

[0062] Combination Figure 1 In some embodiments, the diameter of the aperture of the aperture 100 is EPD, the effective focal length of the projection lens is EFL, and the projection lens satisfies the following expression:

[0063] As in the embodiment of this application, Set to 1.4, 1.8 or 2.0, the embodiment disclosed The smaller the value, the larger the aperture of the projection lens, the higher the light efficiency, and the brighter the projection image can be projected under rated power consumption. The above range can meet the requirements of most optical waveguides for the input luminous flux of the optical machine.

[0064] Combination Figure 1 In some embodiments, it is disclosed that the refractive index of the first lens 10 is n1, and the Abbe number of the first lens 10 is VD1; the refractive index of the second lens 20 is n2, and the Abbe number of the second lens 20 is VD2; the refractive index of the third lens 30 is n3, and the Abbe number of the third lens 30 is VD3; the refractive index of the fourth lens 40 is n4, and the Abbe number of the fourth lens 40 is VD4; the refractive index of the fifth lens 50 is n5, and the Abbe number of the fifth lens 50 is VD5; the projection lens satisfies the following relationship:

[0065] 1.5≤n1≤1.6, 50≤VD1≤65; and / or,

[0066] 1.5≤n2≤1.6, 50≤VD2≤65; and / or,

[0067] 1.63≤n3≤1.7, 20≤VD3≤25; and / or,

[0068] 1.63≤n4≤1.7, 20≤VD4≤25; and / or,

[0069] 1.5≤n5≤1.6,50≤VD5≤65.

[0070] In this embodiment, when the refractive index and the Abbe number of the first lens 10 meet the above ranges, it is beneficial for the first lens 10 to be made of glass; when the refractive index and the Abbe number of the second lens 20, the third lens 30, the fourth lens 40 and the fifth lens 50 meet the above ranges, it is beneficial for the second lens 20, the third lens 30, the fourth lens 40 and the fifth lens 50 to be made of plastic.

[0071] Combination Figure 1, this embodiment discloses that the semi-aperture of the object side surface of the first lens 10 is R11, and the semi-aperture of the image side surface of the first lens 10 is R12; the semi-aperture of the object side surface of the second lens 20 is R21, and the semi-aperture of the image side surface of the second lens 20 is R22; the semi-aperture of the object side surface of the third lens 30 is R31, and the semi-aperture of the image side surface of the third lens 30 is R32; the semi-aperture of the object side surface of the fourth lens 40 is R41, and the semi-aperture of the image side surface of the fourth lens 40 is R42; the semi-aperture of the object side surface of the fifth lens 50 is R51, and the semi-aperture of the image side surface of the fifth lens 50 is R52. At the same time, the aperture diameter of the aperture 100 is EPD, and the projection lens satisfies the following relationship:

[0072] and / or,

[0073] and / or,

[0074] and / or,

[0075] and / or,

[0076]

[0077] In this embodiment, when the ratio of the semi-aperture R of the surface of each projection lens to the EPD satisfies the above range, it is beneficial for the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, and the fifth lens 50 to modulate the light so that the angles between the main light and the marginal light of the lens and the optical axis are respectively within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0078] Combination Figure 1 In some embodiments, based on the semi-aperture R of the object side surface and the image side surface of each lens disclosed in this embodiment, this embodiment further discloses that the curvature of the center point of the object side surface of the first lens 10 is C11, the curvature of the center point of the image side surface of the first lens 10 is C12, the curvature of the center point of the object side surface of the second lens 20 is C21, the curvature of the center point of the image side surface of the second lens 20 is C22, the curvature of the center point of the object side surface of the third lens 30 is C31, the curvature of the center point of the image side surface of the third lens 30 is C32, the curvature of the center point of the object side surface of the fourth lens 40 is C41, the curvature of the center point of the image side surface of the fourth lens 40 is C42, the curvature of the center point of the object side surface of the fifth lens 50 is C51, and the curvature of the center point of the image side surface of the fifth lens 50 is C52; the projection lens satisfies the following relationship:

[0079] and / or,

[0080] and / or,

[0081] and / or,

[0082] and / or,

[0083]

[0084] In this embodiment, along the optical axis direction, in the same optical lens (the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 or the fifth lens 50), when the ratio of the curvature C of the object side surface to the semi-aperture R of the object side surface, and the ratio of the curvature C of the image side surface to the semi-aperture R of the image side surface meet the above ranges, it can be ensured that the lens is scaled without changing the proportion, and it is also beneficial for the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, and the fifth lens 50 to modulate the light so that the angles between the lens principal light and the marginal light and the optical axis are respectively within a certain range, thereby improving the uniformity of the virtual image projected by the projection lens.

[0085] Combination Figure 1 Further, based on the semi-aperture R of the object side surface and the image side surface of each lens disclosed in this embodiment, this embodiment also discloses that the center thickness of the object side surface of the first lens 10 is T11, and the thickness of the image side surface of the first lens 10 is T12; the center thickness of the object side surface of the second lens 20 is T21, and the center thickness of the image side surface of the second lens 20 is T22; the center thickness of the object side surface of the third lens 30 is T31, and the center thickness of the image side surface of the third lens 30 is T32; the thickness of the object side surface of the fourth lens 40 is T41, and the center thickness of the image side surface of the fourth lens 40 is T42; the center thickness of the object side surface of the fifth lens 50 is T51, and the center thickness of the image side surface of the fifth lens 50 is T52; the projection lens satisfies the following relationship:

[0086] and / or,

[0087] and / or,

[0088] and / or,

[0089] and / or,

[0090]

[0091] In this embodiment, when the ratio between the center thickness T and the semi-aperture R of the surface of each projection lens satisfies the above range, it is beneficial for the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, and the fifth lens 50 to modulate the light to control the angles between the main light and the edge light of the lens and the optical axis, respectively, thereby improving the uniformity of the virtual image projected by the projection lens.

[0092] like Figure 1 As shown, an embodiment of the present application also provides an optical machine, including an aperture 100, an image source 200 and a projection lens in any of the above-mentioned embodiments. Since the optical machine uses the above-mentioned projection lens, the uniformity of the virtual image projected by the optical machine can be improved, thereby improving the quality of the virtual image projected by the optical machine.

[0093] like Figure 1 As shown, the embodiment of the present application also provides a near-eye display device, including an optical waveguide and the above-mentioned optical machine, wherein the optical waveguide is arranged on the side of the aperture 100 away from the first lens 10, and is used to receive the light beam emitted by the image source 200, and transmit the light beam to the human eye for near-eye display. Since the near-eye display device of this embodiment uses the above-mentioned optical machine, the uniformity of the virtual image screen projected by the near-eye display device can be improved, thereby improving the quality of the virtual image screen projected by the near-eye display device.

[0094] In order to further illustrate the effects of the projection lens and optical machine of this embodiment, the embodiments of the present application also provide Embodiment 1 and Embodiment 2, as well as the modulation transfer function curve diagram, defocus curve diagram, optical distortion and astigmatism field curvature, TV distortion diagram, chromatic aberration curve diagram, thermal drift defocus curve diagram, etc. of each embodiment to illustrate the effects, so as to make the effects of this embodiment more intuitive.

[0095] Embodiment 1:

[0096] like Figure 1 As shown, the projection lens of this embodiment adopts a MicroLED lens, the image source 200 adopts a MicroLED display screen, and the light intensity distribution curve of the MicroLED display screen (that is, the light intensity distribution curve of the image source 200) is as shown in FIG. Figure 4 As shown. Figure 4 As shown, the normalized relative intensity of the light beam within the receiving angle luminosity range of -20° to 20° is close to 1, indicating that the light intensity of the light beam within the range of -20° to 20° is relatively strong.

[0097] The projection lens of this embodiment is based on Figure 4The light intensity distribution curve shown in FIG. 1 is used to design the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 and the fifth lens 50 to modulate the main light and edge light angles of the lens so that the receiving light angle of the projection lens is adapted to the light intensity angle distribution curve, so that the projection lens is adapted to the image source 200. The light receiving angle curve of the projection lens is as shown in FIG. Figure 5 shown.

[0098] Specifically, along the optical axis direction, from the aperture 100 to the image source 200, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 and the fifth lens 50 are sequentially arranged at intervals, the parameters of each lens are shown in Table 1-1, and the aspheric coefficients of each lens are shown in Table 1-2. In Table 1-1, STOP represents the aperture 100, IMG represents the image source 200, the object side surface S1 of the first lens 10 is a convex surface, the image side surface S2 of the first lens 10 is a convex surface, the object side surface S3 of the second lens 20 is a convex surface, the image side surface S4 of the second lens 20 is a convex surface, the object side surface S5 of the third lens 30 is a convex surface, the image side surface S6 of the third lens 30 is a concave surface, the object side surface S7 of the fourth lens 40 is a concave surface, the image side surface S8 of the fourth lens 40 is a convex surface, the object side surface S9 of the fifth lens 50 is a convex surface, and the image side surface S10 of the fifth lens 50 is an M-shaped curved surface. The basic optical parameters of the projection lens with parameters shown in Table 1-1 are: the diagonal field of view FOV of the projection lens is 25°, the aperture diameter EPD of the aperture 100 is 4.8 mm, and the F number (F#, F-number, relative aperture) is 1.48. Table 1-2 is an aspheric coefficient table, which shows the aspheric coefficients of each lens surface of the projection lens of this embodiment.

[0099] Table 1-1

[0100]

[0101] Table 1-2

[0102]

[0103]

[0104] In this embodiment, each surface of the lens is an even-order aspheric surface, and the surface shapes shown above satisfy the aspheric surface formula:

[0105]

[0106] Among them, z is the vector height of the lens surface under different apertures, c is the inverse of the radius of curvature R, r is the aperture in the radial direction, k is the cone coefficient (i.e. conic), and A, B, C, D, E, F, G, H, and J are all high-order coefficients.

[0107] Furthermore, the projection lens disclosed in the first embodiment was tested in combination with a MicroLED display screen.

[0108] Combination Figure 4 and Figure 5 , the normalized relative intensity of the light beam in the range of -20° to 20° is close to 1, and the light receiving angles at various positions from the center to the edge of the projection lens are between 0° and 6°, indicating that the projection lens has high light efficiency. The receiving light angle is the angle between the light beam and the optical axis.

[0109] like Figure 6 As shown, this embodiment discloses a uniformity simulation structure diagram, combined with Figure 5 and Figure 6 The received light angles at each position from the center to the edge of the projection lens are all between 0° and 6°. The smaller the received light angles, the closer the light intensity received at each field of view angle of the projection lens is. Therefore, the illumination difference between each position from the center to the edge of the virtual image projected by the projection lens is, and the uniformity of the virtual image is better.

[0110] Furthermore, Figure 6 The illumination data of each point is shown in Table 1-3:

[0111] Table 1-3

[0112] 10：196.35 11：197.00 1：198.04 2：199.34 3：197.87 4：198.89 5：202.23 6：199.11 7：197.92 8：197.92 9：196.86 12：196.95 13：196.11

[0113] Combining relevant technologies and calculating according to ANSI 13 points, the brightness uniformity values ​​are as follows:

[0114]

[0115] In the above formula, min(13Point) represents the minimum value among the 13 values ​​in Table 1-3, and max(13Point) represents the maximum value among the 13 values ​​in Table 1-3. It can be seen from the above formula that the brightness uniformity of the virtual image projected by the MicroLED lens of the first embodiment is 97%. This shows that the present embodiment can improve the brightness uniformity of the virtual image projected by the current MicroLED lens from 80% to 97%, thereby showing that the projection lens of the present embodiment can greatly improve the brightness uniformity of the virtual image projected by the lens.

[0116] like Figure 7 As shown, the modulation transfer function curve of the projection lens in the first embodiment disclosed in this embodiment, the modulation transfer function (MTF for short), refers to the relationship between the modulation degree and the number of line pairs per millimeter in the image, which can be used to evaluate the imaging quality of the lens and measure the lens's ability to restore object details. Figure 7 In the figure, the minimum value of the modulation transfer function is 0.8. The closer the curve in the MTF is to 1, the better. The closer to 1, the better the imaging quality of the lens. It can be seen that the higher the curve of the modulation transfer function, the clearer the image, which means that the virtual image projected by the projection lens of this embodiment has high clarity.

[0117] like Figure 8 As shown, the defocus curve diagram of the projection lens in the first embodiment disclosed in this embodiment, Figure 8 In the figure, the horizontal axis is the defocus distance, and the vertical axis is the OTF (Optical Transfer Function) modulus. The defocus curve represents the change of MTF when the image plane deviates from the design value. Figure 8 In the figure, the defocus curves of each field of view have good convergence, which means that the virtual image projected by the projection lens of this embodiment has high overall clarity in the entire field of view.

[0118] like Fig. 9 As shown, the optical distortion and astigmatism field curvature diagram of the projection lens in the first embodiment disclosed in this embodiment, Fig. 9 In the figure, the optical distortion is within 1.1%. The smaller the distortion, the better the shape-preserving effect. This shows that the projection lens of this embodiment can project a virtual image screen with no obvious visual deformation.

[0119] like Fig.10 As shown, the TV distortion diagram of the projection lens in the first embodiment disclosed in this embodiment is: Fig.10 It can be seen from the figure that the virtual image projected by the projection lens of this embodiment is clear and has no obvious deformation.

[0120] like Fig.11 As shown, the axial chromatic aberration curve of the projection lens in the first embodiment disclosed in this embodiment is as follows: Fig.11 In the figure, the ordinate is the longitudinal spherical aberration, and the abscissa is the focus shift. Fig.11 In the figure, the maximum distance between the curves is less than 0.003 mm, and the spacing is small, which means that the virtual image projected by the projection lens of this embodiment has good color difference.

[0121] like Fig.12 As shown, the vertical axis chromatic aberration curve of the projection lens in the first embodiment disclosed in this embodiment is as follows: Fig.12 In the figure, the maximum offset of different wavelengths is 0.001 mm. The smaller the vertical axis chromatic aberration is, the higher the image quality is and the clearer the image is. This indicates that the virtual image projected by the projection lens of this embodiment is clear and has good image quality.

[0122] like Fig.13 , Fig.14 and Fig.15As shown in FIG. 1 , the thermal drift defocus curves of the optical machine with the projection lens of Example 1 disclosed in this embodiment at -10°, 20°, and 50° are shown in FIG. Figures 13 to 15 It can be seen that by using the projection lens of this embodiment, the thermal drift performance of the optical machine is improved, and the optical machine can work well under different ambient temperatures to ensure the clarity of the projected virtual image.

[0123] It can be seen from the above embodiments that the projection lens of this embodiment can improve the brightness uniformity of the virtual image projected by the lens, and the performance parameters such as MTF (Modulation Transfer Function), distortion, light efficiency, thermal drift, etc. can be at a high level. Therefore, the optical machine with the projection lens is used in combination with the optical waveguide, which can improve the quality of the image entering the eye and meet the high-standard imaging quality requirements.

[0124] Embodiment 2:

[0125] like Figure 3 As shown, the main differences between this embodiment and the first embodiment are: a light receiving angle curve of the projection lens, basic optical parameters of the projection lens, and specific parameters of each optical lens.

[0126] Specifically, the light receiving angle curve of the projection lens is as follows: Fig.16 As shown, the receiving light angle of this embodiment is also adapted Figure 4 The light intensity angle distribution curve is shown so that the projection lens of this embodiment is also adapted to the image source 200.

[0127] Specifically, the basic optical parameters of the projection lens are: the diagonal field of view FOV of the projection lens is 26°, the aperture diameter EPD of the aperture 100 is 5.0 mm, and the F number (F#, F-number, relative aperture) is 1.47. The specific parameters of each optical lens are shown in Table 2-1.

[0128] Table 2-1

[0129]

[0130] Table 2-2

[0131]

[0132]

[0133] The above Table 2-2 is an aspheric coefficient table, which shows the aspheric coefficients of each lens surface of the projection lens of this embodiment.

[0134] Furthermore, the projection lens disclosed in the second embodiment was tested in combination with a MicroLED display screen.

[0135] Combination Figure 4 and Fig.16 , the normalized relative intensity of the light beam in the range of -20° to 20° is close to 1, and the light receiving angles at various positions from the center to the edge of the projection lens are between 0° and 6°, indicating that the projection lens has high light efficiency. The receiving light angle is the angle between the light beam and the optical axis.

[0136] like Fig.17 As shown, this embodiment discloses a uniformity simulation structure diagram, combined with Fig.16 and Fig.17 The received light angles at each position from the center to the edge of the projection lens are all between 0° and 6°. The smaller the received light angles, the closer the light intensity received at each field of view angle of the projection lens is. Therefore, the illumination difference between each position from the center to the edge of the virtual image projected by the projection lens is, and the uniformity of the virtual image is better.

[0137] Furthermore, Fig.17 The illumination data of each point is shown in Table 2-3:

[0138] Table 2-3

[0139] 10：235.02 11：235.09 1：237.05 2：240.08 3：235.24 4：237.68 5：243.44 6：238.06 7：236.24 8：240.17 9：236.10 12：235.39 13：234.69

[0140] Combining relevant technologies and calculating according to ANSI 13 points, the brightness uniformity values ​​are as follows:

[0141]

[0142] In the above formula, min(13Point) represents the minimum value among the 13 values ​​in Table 2-3, and max(13Point) represents the maximum value among the 13 values ​​in Table 2-3. It can be seen from the above formula that the brightness uniformity of the virtual image screen projected by the MicroLED lens of the second embodiment is 96.4%. This shows that the present embodiment can improve the brightness uniformity of the virtual image screen projected by the current MicroLED lens from 80% to 96.4%, thereby showing that the projection lens of the present embodiment can greatly improve the brightness uniformity of the virtual image screen projected by the lens.

[0143] like Fig.18 As shown, the modulation transfer function curve of the projection lens in the second embodiment disclosed in this embodiment, the modulation transfer function (MTF for short), refers to the relationship between the modulation degree and the number of line pairs per millimeter in the image, which can be used to evaluate the imaging quality of the lens and measure the lens's ability to restore object details. Fig.18In the figure, the minimum value of the modulation transfer function is 0.7. The closer the curve in the MTF is to 1, the better. The closer to 1, the better the imaging quality of the lens. It can be seen that the higher the curve of the modulation transfer function, the clearer the image, which means that the virtual image projected by the projection lens of this embodiment is clearer.

[0144] like Fig.19 As shown, the defocus curve of the projection lens in the second embodiment disclosed in this embodiment is as follows: Fig.19 In the figure, the horizontal axis is the defocus distance, and the vertical axis is the OTF (Optical Transfer Function) modulus. The defocus curve represents the change of MTF when the image plane deviates from the design value. Fig.19 In the figure, the defocus curves of each field of view have good convergence, which means that the virtual image projected by the projection lens of this embodiment is relatively clear.

[0145] like Fig. 20 As shown, the optical distortion and astigmatism field curvature diagram of the projection lens in the second embodiment disclosed in this embodiment, Fig. 20 In the figure, the optical distortion is within 2%. The smaller the distortion, the better the shape-preserving effect. This shows that the projection lens of this embodiment can project a virtual image screen with no obvious visual deformation.

[0146] like Fig.21 As shown, the TV distortion diagram of the projection lens in the second embodiment disclosed in this embodiment is: Fig.21 It can be seen from the figure that the virtual image projected by the projection lens of this embodiment is clear and has no obvious deformation.

[0147] like Fig. 22 As shown, the axial chromatic aberration curve of the projection lens in the second embodiment disclosed in this embodiment is as follows: Fig. 22 In the figure, the ordinate is the longitudinal spherical aberration, and the abscissa is the focus shift. Fig. 22 In the figure, the maximum distance between the curves is less than 0.004 mm, and the spacing is small, which means that the virtual image projected by the projection lens of this embodiment has good color difference.

[0148] like Fig.23 As shown, the vertical axis chromatic aberration curve of the projection lens in the second embodiment disclosed in this embodiment is as follows: Fig.23 In the figure, the maximum offset of different wavelengths is 0.003 mm. The smaller the vertical axis chromatic aberration is, the higher the image quality is and the clearer the image is. This indicates that the virtual image projected by the projection lens of this embodiment is clear and has good image quality.

[0149] like Figure 24 to Figure 26 As shown in FIG. 1 , the thermal drift defocus curves of the optical machine with the projection lens of Example 2 disclosed in this embodiment at -10°, 20°, and 50° are shown in FIG. Figure 24 to Figure 26It can be seen that by using the projection lens of this embodiment, the thermal drift performance of the optical machine is improved, and the optical machine can work well under different ambient temperatures to ensure the clarity of the projected virtual image.

[0150] It can be seen from the above embodiments that the projection lens of this embodiment can improve the brightness uniformity of the virtual image projected by the lens, and the performance parameters of the projection lens such as MTF (modulation transfer function), distortion, light efficiency, thermal drift, etc. can be at a relatively high level. Therefore, the optical machine with the projection lens can be used in combination with an optical waveguide to improve the quality of the image entering the eye and meet high-standard imaging quality requirements.

[0151] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A projection lens, applied to an optical machine, wherein the optical machine comprises an aperture and an image source, characterized in that: The projection lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, and along the optical axis direction, the aperture, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the image source are arranged in sequence from the object side to the image side; The first lens, the second lens, the fourth lens and the fifth lens all have positive optical power; the third lens has negative optical power; The object side surface of the first lens is a convex surface, the object side surface of the second lens is a convex surface, the image side surface of the third lens is a concave surface, and the image side surface of the fifth lens is an M-shaped curved surface.

2. The projection lens according to claim 1, wherein: The image side surface of the first lens is a convex surface; and / or the image side surface of the second lens is a convex surface.

3. The projection lens according to claim 1, wherein: The object side surface of the third lens is a convex surface; and / or the object side surface of the fifth lens is a convex surface or an M-shaped curved surface.

4. The projection lens according to claim 1, wherein: The image side surface of the fourth lens is convex, and the object side surface of the fourth lens is concave; or, the image side surface of the fourth lens is concave, and the object side surface of the fourth lens is convex.

5. The projection lens according to claim 1, wherein: The first lens is a glass lens, and the second lens, the third lens, the fourth lens and the fifth lens are all plastic lenses.

6. The projection lens according to claim 1, wherein: The projection lens satisfies the following expressions: 20°≤FOV≤35°; and / or, 3.0 mm≤EPD≤5.5 mm; The field of view angle of the projection lens in the diagonal direction is FOV, and the aperture diameter of the aperture is EPD.

7. The projection lens according to claim 1, wherein: The projection lens satisfies the following expression: 1.3≤ EFL ≤2.5 EPD, The aperture diameter of the aperture is EPD, and the effective focal length of the projection lens is EFL.

8. The projection lens according to claim 1, wherein: The projection lens satisfies at least one of the following relationships: 1.5≤n1≤1.6, 50≤VD1≤65; and / or, 1.5≤n2≤1.6, 50≤VD2≤65; and / or, 1.63≤n3≤1.7, 20≤VD3≤25; and / or, 1.63≤n4≤1.7, 20≤VD4≤25; and / or, 1.5≤n5≤1.6,50≤VD5≤65; Among them, the refractive index of the first lens is n1, and the Abbe number of the first lens is VD1; the refractive index of the second lens is n2, and the Abbe number of the second lens is VD2; the refractive index of the third lens is n3, and the Abbe number of the third lens is VD3; the refractive index of the fourth lens is n4, and the Abbe number of the fourth lens is VD4; the refractive index of the fifth lens is n5, and the Abbe number of the fifth lens is VD5.

9. The projection lens according to claim 1, wherein: The projection lens satisfies at least one of the following relationships: and / or, and / or, and / or, and / or, Among them, the semi-diameter of the object side surface of the first lens is R11, and the semi-diameter of the image side surface of the first lens is R12; the semi-diameter of the object side surface of the second lens is R21, and the semi-diameter of the image side surface of the second lens is R22; the semi-diameter of the object side surface of the third lens is R31, and the semi-diameter of the image side surface of the third lens is R32; the semi-diameter of the object side surface of the fourth lens is R41, and the semi-diameter of the image side surface of the fourth lens is R42; the semi-diameter of the object side surface of the fifth lens is R51, and the semi-diameter of the image side surface of the fifth lens is R52; the aperture diameter of the aperture is EPD.

10. The projection lens according to claim 1, wherein: The projection lens satisfies at least one of the following relationships: and / or, and / or, and / or, and / or, wherein the curvature of the object side surface center point of the first lens is C11, the curvature of the image side surface center point of the first lens is C12, the curvature of the object side surface center point of the second lens is C21, the curvature of the image side surface center point of the second lens is C22, the curvature of the object side surface center point of the third lens is C31, the curvature of the image side surface center point of the third lens is C32, the curvature of the object side surface center point of the fourth lens is C41, the curvature of the image side surface center point of the fourth lens is C42, the curvature of the object side surface center point of the fifth lens is C51, and the curvature of the image side surface center point of the fifth lens is C52; The semi-diameter of the object side surface of the first lens is R11, and the semi-diameter of the image side surface of the first lens is R12; the semi-diameter of the object side surface of the second lens is R21, and the semi-diameter of the image side surface of the second lens is R22; the semi-diameter of the object side surface of the third lens is R31, and the semi-diameter of the image side surface of the third lens is R32; the semi-diameter of the object side surface of the fourth lens is R41, and the semi-diameter of the image side surface of the fourth lens is R42; the semi-diameter of the object side surface of the fifth lens is R51, and the semi-diameter of the image side surface of the fifth lens is R52.

11. The projection lens according to claim 1, wherein: The projection lens satisfies at least one of the following relationships: and / or, and / or, and / or, and / or, The center thickness of the object side surface of the first lens is T11, and the center thickness of the image side surface of the first lens is T12; the center thickness of the object side surface of the second lens is T21, and the center thickness of the image side surface of the second lens is T22; the center thickness of the object side surface of the third lens is T31, and the center thickness of the image side surface of the third lens is T32; the thickness of the object side surface of the fourth lens is T41, and the center thickness of the image side surface of the fourth lens is T42; the center thickness of the object side surface of the fifth lens is T51, and the center thickness of the image side surface of the fifth lens is T52; The semi-diameter of the object side surface of the first lens is R11, and the semi-diameter of the image side surface of the first lens is R12; the semi-diameter of the object side surface of the second lens is R21, and the semi-diameter of the image side surface of the second lens is R22; the semi-diameter of the object side surface of the third lens is R31, and the semi-diameter of the image side surface of the third lens is R32; the semi-diameter of the object side surface of the fourth lens is R41, and the semi-diameter of the image side surface of the fourth lens is R42; the semi-diameter of the object side surface of the fifth lens is R51, and the semi-diameter of the image side surface of the fifth lens is R52.

12. An optical machine, characterized in that: The invention comprises an aperture, an image source and a projection lens as claimed in any one of claims 1 to 11.

13. A near-eye display device, characterized in that: It comprises an optical waveguide and an optical machine according to claim 12, wherein the optical waveguide is arranged on a side of the aperture away from the first lens, and is used to receive the light beam emitted by the image source and transmit the light beam to the human eye for near-eye display.

Images