Projection lens and near-to-eye display device

Abstract

The utility model provides a projection lens. The projection lens comprises a first lens, a second lens, a beam splitter prism, a plane lens, a reflection lens, a third lens and a modulation chip which are sequentially arranged from an object side to an image side, wherein the beam splitter prism is used for receiving and guiding light source light and image light; the first lens and the second lens are arranged on the first side surface of the beam splitter prism and are used for receiving and projecting image light emitted from the beam splitter prism; the plane lens and the reflecting lens are arranged on the second side surface of the beam splitter prism; the third lens and the modulation chip are arranged on the third side face of the beam splitter prism, and the modulation chip is used for receiving the light source light, modulating the light source light into image light and then emitting the image light to the reflection lens. The projection lens meets the condition that FOV / FNO is larger than 15.7, FOV is the maximum field angle of the projection lens, and FNO is the relative aperture F number of the projection lens. The projection lens provided by the utility model is beneficial to meeting the field angle requirement and the optical efficiency. The utility model further provides a near-to-eye display device.

Description

Technical Field

[0001] This application relates to the field of optics, and more particularly to projection lenses and near-eye display devices. Background Technology

[0002] With advancements in imaging technology, the demand for immersive experiences is increasing. Near-eye display devices employing augmented reality (AR) technology offer a certain level of transmittance, allowing wearers to see both the image and the surrounding environment. Image quality and thinness are key considerations for near-eye display devices. A common near-eye display device uses a projection module based on Liquid Crystal on Silicon (LCoS) technology as its display chip. However, LCoS optical systems typically have a large optical volume, impacting the comfort and portability of the near-eye display device. Utility Model Content

[0003] This application provides a projection lens, comprising a first lens, a second lens, a beam splitter, a plane lens, a reflecting lens, a third lens, and a modulation chip arranged sequentially from the object side to the image side; wherein...

[0004] The beam splitter is used to receive and guide the light source light and the image light;

[0005] The first lens and the second lens are disposed on the first side of the beam splitter, and the second lens is disposed between the first lens and the beam splitter. The first lens and the second lens are used to receive and project the image light emitted from the beam splitter. The object side of the first lens is convex and the image side is concave. The object side of the second lens is convex and the image side is convex.

[0006] The planar lens and the reflecting lens are disposed on the second side of the beam splitter, the planar lens is disposed between the reflecting lens and the beam splitter, and the reflecting lens is used to reflect the image light; the reflecting lens includes a reflecting surface, and the reflecting surface is concave.

[0007] The third lens and the modulation chip are disposed on the third side of the beam splitter. The third lens is disposed between the modulation chip and the beam splitter. The modulation chip is used to receive the light source light and modulate the light source light into the image light before it is emitted to the reflecting lens. The object side of the third lens is convex and the image side is concave.

[0008] The projection lens satisfies FOV / FNO > 15.7, where FOV is the maximum field of view of the projection lens and FNO is the relative aperture F-number of the projection lens.

[0009] The projection lens provided by this application, by adopting the above optical elements and setting the surface shape conditions of each optical element, is conducive to the reasonable distribution of the optical power of the projection lens, thereby facilitating the balance and correction of various aberrations of the projection lens. By adopting the configuration of FOV / FNO > 15.7, it is conducive to the projection lens meeting the requirements of the viewing angle, thereby ensuring the projection field of view of the projection lens and ensuring the optical efficiency when paired with the optical engine. Thus, when the projection lens is applied to a near-eye display device, the portability and comfort of the near-eye display device are improved.

[0010] In one embodiment, the projection lens further includes an aperture stop, and the aperture stop is disposed on a side of the first lens away from the second lens.

[0011] In one embodiment, the first lens has a negative optical power, the second lens has a positive optical power, the reflecting lens has a positive optical power, and the third lens has a positive optical power.

[0012] In one embodiment, the reflecting surface is a spherical surface or an aspherical surface.

[0013] In one embodiment, the first lens and the second lens are spaced apart or are in contact with each other.

[0014] In one embodiment, the projection lens satisfies -1.4° < CRA < 1.4°, where CRA is the incident angle of the chief ray on the image plane.

[0015] The projection lens provided by the embodiment of this application, by setting the range of CRA, is conducive to the assembly of the projection lens and is conducive to the cooperation between the projection lens and the optical engine.

[0016] In one embodiment, the projection lens satisfies -0.35 < f2 / f1 < -0.23, where f1 is the effective focal length of the first lens and f2 is the effective focal length of the second lens.

[0017] The projection lens provided by the embodiment of this application, by setting -0.35 < f2 / f1 < -0.23, can match the positive and negative focal lengths of the first lens and the second lens, thereby facilitating the correction of longitudinal chromatic aberration.

[0018] In one embodiment, the projection lens satisfies 1.61 < (f3 / f) < 2.15, where f3 is the effective focal length of the reflecting lens and f is the effective focal length of the projection lens.

[0019] The projection lens provided by the embodiment of this application, by setting 1.61 < (f3 / f) < 2.15, is conducive to controlling the length ratio of the projection lens in different directions and is conducive to using a beam splitter prism of a suitable size.

[0020] In one embodiment, the projection lens satisfies f1(1 / R1_1-1 / R1_2)>2.12, where R1_1 is the radius of curvature of the object side of the first lens, R1_2 is the radius of curvature of the image side of the first lens, and f1 is the effective focal length of the first lens.

[0021] The projection lens provided in this application embodiment can limit the shape of the first lens by setting f1(1 / R1_1-1 / R1_2)>2.12, which is beneficial for balancing field curvature aberration.

[0022] In one embodiment, the projection lens satisfies TTLV / IMH < 3.4, where TTLV is the distance along the optical axis from the reflecting surface of the reflecting lens to the modulation surface of the modulation chip, and IMH is half the diagonal length of the modulation surface.

[0023] The projection lens provided in this application embodiment, by setting TTLV / IMH<3.4, ​​helps to limit the size of the lens to meet the requirements of a thin and light structure and helps to balance aberrations.

[0024] In one embodiment, the projection lens satisfies TTLH / IMH < 3.2, where TTLH is the distance along the optical axis from the object side of the first lens to the first side of the beam splitter, and IMH is half the length of the diagonal of the modulation surface of the modulation chip.

[0025] The projection lens provided in this application embodiment, by setting TTLV / IMH<3.4, ​​helps to limit the size of the lens to meet the requirements of a thin and light structure and helps to balance aberrations.

[0026] In one embodiment, the projection lens satisfies BFL > 1.15 mm, where BFL is the distance along the optical axis from the image-side surface of the third lens to the modulation surface of the modulation chip.

[0027] The projection lens provided in this application embodiment, by setting BFL>1.15mm, helps to limit the size of the lens to meet the requirements of a thin and light structure, and is easy to adapt to the surface structure of the modulation chip.

[0028] In one embodiment, the first lens satisfies f1 / D1>0.35, where f1 is the effective focal length of the first lens and D1 is the effective aperture of the first lens.

[0029] The projection lens provided in this application embodiment can limit the shape of the first lens by setting f1 / D1>0.35, which is beneficial for balancing field curvature and aberrations.

[0030] In one embodiment, the third lens satisfies f6(1 / R6_1-1 / R6_2)>1.97, where f6 is the effective focal length of the third lens, R6_1 is the radius of curvature of the object side of the third lens, and R6_2 is the radius of curvature of the image side of the third lens.

[0031] The projection lens provided in this application embodiment can limit the shape of the third lens by setting f6(1 / R6_1-1 / R6_2)>1.97, which is beneficial for designing the incident angle of the principal ray of the image plane.

[0032] This application also provides a near-eye display device, comprising: the aforementioned projection lens; an optical engine for emitting light from the projection lens; and an imaging module for receiving image light emitted from the projection lens.

[0033] The near-eye display device provided in this application embodiment, by setting the projection lens as described in the above embodiment and by setting the parameters of the optical elements in the projection lens, facilitates the reasonable allocation of the optical power of the projection lens, thereby facilitating the balance and correction of various aberrations of the projection lens; it also helps the projection lens meet the requirements of the field of view, thereby ensuring the projection field of view of the projection lens, and can ensure the optical efficiency when paired with the optical engine, thereby improving the portability and comfort of the near-eye display device when the projection lens is applied to the near-eye display device. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the projection lens in Embodiment 1 of this application.

[0035] Figure 2 These are the astigmatism and distortion curves of the projection lens in Embodiment 1 of this application.

[0036] Figure 3 This is the magnification chromatic aberration curve of the projection lens in Embodiment 1 of this application.

[0037] Figure 4 This is the on-axis chromatic aberration curve of the projection lens in Embodiment 1 of this application.

[0038] Figure 5 This is the modulation transfer function curve of the projection lens in Embodiment 1 of this application.

[0039] Figure 6 This is the incident angle curve of the principal ray of the projection lens in Embodiment 1 of this application.

[0040] Figure 7 This is a schematic diagram of the projection lens in Embodiment 2 of this application.

[0041] Figure 8 These are the astigmatism and distortion curves of the projection lens in Embodiment 2 of this application.

[0042] Figure 9 This is the magnification chromatic aberration curve of the projection lens in Embodiment 2 of this application.

[0043] Figure 10 This is the on-axis chromatic aberration curve of the projection lens in Embodiment 2 of this application.

[0044] Figure 11 This is the modulation transfer function curve of the projection lens in Embodiment 2 of this application.

[0045] Figure 12 This is the incident angle curve of the principal ray of the projection lens in Embodiment 2 of this application.

[0046] Figure 13 This is a schematic diagram of the near-eye display device in the embodiments of this application.

[0047] Explanation of main component symbols

[0048] Projection lens: 100

[0049] First lens: 10

[0050] First object side view: S1

[0051] First image, side view: S2

[0052] Second lens: 20

[0053] Second side view: S3

[0054] Second image, side view: S4

[0055] Beam splitter: 30

[0056] First side view: S5

[0057] Second side view: S8

[0058] Transmission and reflection surface: S9

[0059] Third side view: S10

[0060] Fourth side view: S16

[0061] Plane lens: 40

[0062] Transmission plane: S7

[0063] Reflecting lens: 50

[0064] Reflective surface: S6

[0065] Third lens: 60

[0066] Third object side view: S11

[0067] Third image, side view: S12

[0068] Modulation chip: 70

[0069] Protect tablet: 71

[0070] Fourth object side view: S13

[0071] Fourth image, side view: S14

[0072] Modulation module: 73

[0073] Modulation surface: S15

[0074] Aperture: STO

[0075] Near-eye display device: 200

[0076] Optical mechanism: 210

[0077] Imaging module: 230

[0078] Light source: L1

[0079] Image light: L2

[0080] Eyes: E.

[0081] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0082] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0083] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0084] To further illustrate the technical means and effects adopted by this application in achieving its intended purpose, the following detailed description of this application is provided in conjunction with the accompanying drawings and preferred embodiments.

[0085] Please see Figure 1 The projection lens 100 provided in this application embodiment includes a first lens 10, a second lens 20, a beam splitter 30, a plane lens 40, a reflecting lens 50, a third lens 60, and a modulation chip 70 arranged sequentially from the object side to the image side. The image side is the side of the projection lens 100 that receives the light source light L1, and the object side is the side of the projection lens 100 that projects the emitted image light L2.

[0086] The beam splitter 30 is used to receive and guide the light source light L1 and the image light L2. The beam splitter 30 includes a first side surface S5 and a fourth side surface S16 arranged opposite each other, a second side surface S8 and a third side surface S10 arranged opposite each other, and a transmissive / reflective surface S9 arranged at an angle. From the object side to the image side, the first side surface S5, the second side surface S8, the third side surface S10, and the fourth side surface S16 are arranged sequentially. The transmissive / reflective surface S9 is disposed between the first side surface S5 and the fourth side surface S16, and between the second side surface S8 and the third side surface S10.

[0087] A first lens 10 and a second lens 20 are disposed on the first side surface S5 of the beam splitter 30, and the second lens 20 is disposed between the first lens 10 and the beam splitter 30. The first lens 10 and the second lens 20 are used to receive and project image light L2 emitted from the beam splitter 30. The first object-side surface S1 of the first lens 10 is convex, and the first image-side surface S2 is concave; the first lens 10 has negative optical power. The second object-side surface S3 of the second lens 20 is convex, and the second image-side surface S4 is convex; the second lens 20 has positive optical power.

[0088] A plane lens 40 and a reflecting lens 50 are disposed on the second side S8 of the beam splitter 30. The reflecting lens 50 is used to reflect image light L2. The reflecting lens 50 includes a reflecting surface S6, which is concave. The reflecting lens 50 has positive optical power.

[0089] The third lens 60 and the modulation chip 70 are disposed on the third side surface S10 of the beam splitter 30, with the third lens 60 positioned between the modulation chip 70 and the beam splitter 30. The modulation chip 70 receives the light source light L1 and modulates it into image light L2 before projecting it onto the reflecting lens 50. The object side surface S11 of the third lens 60 is convex, and the image side surface S12 is concave. The third lens 60 has positive optical power.

[0090] The projection lens 100 also includes an aperture stop STO, which is located on the side of the first lens 10 away from the second lens 20.

[0091] Specifically, light source L1 is incident from the image side onto the fourth side surface S16. The light source L1 incident from the fourth side surface S16 is reflected by the transmission and reflection surface S9 towards the third side surface S10, thus projecting onto the modulation chip 70. The modulation chip 70 modulates the light source L1 into image light L2 and reflects it back to the third side surface S10. The image light L2 passes sequentially through the transmission and reflection surface S9 and the second side surface S8, and is incident on the reflection surface S6. The reflection surface S6 reflects the image light L2 outwards. The image light L2 passes again through the second side surface S8 and is reflected by the transmission and reflection surface S9, thus passing through the first side surface S5, and finally passing through the second lens 20, the first lens 10, and the aperture stop STO before being projected outwards towards the object side.

[0092] The projection lens 100 satisfies -1.4° < CRA < 1.4°, where CRA is the incident angle of the chief ray on the image plane, that is, the maximum angle of the light rays that can converge to the object plane after exiting the image plane. By setting the range of CRA, the projection lens 100 provided in the embodiment of the present application is beneficial to the assembly of the projection lens 100 and is also beneficial to the cooperation with the optical engine when the projection lens 100 is applied to a near-eye display device, thereby achieving the effect of thinning.

[0093] The projection lens 100 satisfies -0.35 < f2 / f1 < -0.23, where f1 is the effective focal length of the first lens 10 and f2 is the effective focal length of the second lens 20. By setting the range of the ratio of the effective focal length of the second lens 20 to the effective focal length of the first lens 10, the positive and negative focal lengths of the first lens 10 and the second lens 20 can be matched, which is beneficial to the correction of magnification chromatic aberration. Specifically, the first lens 10 and the second lens 20 can form an achromatic lens group for correcting the magnification chromatic aberration of the projection lens 100.

[0094] The projection lens 100 satisfies 1.61 < (f3 / f) < 2.15, where f3 is the effective focal length of the reflecting lens 50 and f is the effective focal length of the projection lens 100. By setting the range of the ratio of the effective focal length of the reflecting lens 50 to the effective focal length of the projection lens 100, it is beneficial to control the length ratio of the projection lens 100 in different directions and is also beneficial to using a beam splitter prism 30 of a suitable size. Specifically, the range of the ratio of the effective focal length of the reflecting lens 50 to the effective focal length of the projection lens 100 can limit the length ratio of the projection lens 100 in the direction from the first side S5 to the fourth side S16 and in the direction from the second side S8 to the third side S10. By setting the above range, the aspect ratio of the projection lens 100 can be controlled, thereby improving the space utilization rate of the projection lens 100.

[0095] The first lens 10 satisfies f1(1 / R1_1 - 1 / R1_2) > 2.12, where R1_1 is the radius of curvature of the first object side S1 of the first lens 10, R1_2 is the radius of curvature of the first image side S2 of the first lens 10, and f1 is the effective focal length of the first lens 10. By setting the numerical range between the radius of curvature of the first object side S1 and the second object side S2 of the first lens 10 and the effective focal length of the first lens 10, the shape of the first lens 10 can be limited, which is beneficial to balancing field curvature aberration.

[0096] The projection lens 100 also satisfies TTLV / IMH < 3.4, where TTLV is the distance along the optical axis from the reflecting surface S6 of the reflecting lens 50 to the modulation surface S15 of the modulation chip 70, and IMH is half the diagonal length of the modulation surface S15. Specifically, the modulation chip 70 includes a protective plate 71 and a modulation module 73. The protective plate 71 is disposed on the modulation module 73, which includes the modulation surface S15. The modulation module 73 modulates the light source light L1 into image light L2 by controlling the reflection of the modulation surface S15. The protective plate 71 is used to protect the modulation module 73. By setting the ratio range between TTLV and the size of the modulation surface S15, it is beneficial to limit the size of the projection lens 100, thereby meeting the requirements of a thin and light structure and facilitating the balance of aberrations.

[0097] The projection lens 100 also satisfies TTLH / IMH < 3.2, where TTLH is the distance along the optical axis from the first object side surface S1 of the first lens 10 to the first side surface S5 of the beam splitter 30. By setting the range of the ratio between TTLH and IMH, it is beneficial to limit the size of the projection lens 100, thereby meeting the requirements of a thin and light structure, and also beneficial to balance aberrations.

[0098] The projection lens 100 also satisfies BFL > 1.15 mm, where BFL is the distance along the optical axis from the third image side surface S12 of the third lens 60 to the modulation surface S15. By setting the range of BFL, it is beneficial to limit the size of the lens to meet the requirements of a thin and light structure, and it is easy to adapt to the surface structure of the modulation chip 70.

[0099] The first lens 10 satisfies f1 / D1>0.35, where f1 is the effective focal length of the first lens 10 and D1 is the effective aperture of the first lens 10. Setting the range of the ratio of the effective focal length to the effective aperture of the first lens 10 can limit the shape of the first lens 10, which is beneficial for balancing field curvature and aberrations.

[0100] The third lens 60 satisfies f6(1 / R6_1-1 / R6_2)>1.97, where f6 is the effective focal length of the third lens 60, R6_1 is the radius of curvature of the third object-side surface S11 of the third lens 60, and R6_2 is the radius of curvature of the third image-side surface S12 of the third lens 60. By setting the radii of curvature of the third object-side surface S11 and the third image-side surface S12 of the third lens 60 to satisfy the above range with the effective focal length of the third lens 60, the shape of the third lens 60 can be restricted, which is beneficial for designing the incident angle of the principal ray of the image plane.

[0101] The projection lens 100 provided in this application will be further described below with reference to specific embodiments.

[0102] Example 1

[0103] Please refer to further information. Figure 1 In Embodiment 1 of this application, the first lens 10 and the second lens 20 are spaced apart, the reflecting lens 50 is attached to the transmission plane of the plane lens 40, and the other side of the plane lens 40 is attached to the second side surface S8 of the beam splitter 30. The reflecting surface S6 is spherical.

[0104] The parameters of each optical surface in the projection lens 100 of this embodiment are shown in Table 1.

[0105] Table 1 Optical Surface Parameters of Projection Lens 100

[0106]

[0107] The optical parameters of the projection lens 100 in this embodiment are shown in Table 2.

[0108] Table 2 Optical parameters of projection lens 100

[0109]

[0110] In this embodiment, the IMH is 2.7mm, the ratio of the modulation surface S15 is 4:3, the FOV of the projection lens 100 is 37.6°, and the effective focal length f of the projection lens 100 is 8.1mm.

[0111] Please see Figure 2 As can be seen from the astigmatism curve, the offset of the projection lens 100 in Embodiment 1 of this application is basically below 0.025mm. As can be seen from the distortion curve, the distortion of the projection lens 100 is controlled within 2.5%. This indicates that the projection lens 100 in Embodiment 1 of this application can effectively correct astigmatism and distortion.

[0112] Please see Figure 3 As can be seen from the magnification color difference curve, the color difference at different image heights is relatively small, and can be basically controlled below 0.003mm. This indicates that the projection lens 100 can effectively correct color difference.

[0113] Please see Figure 4 As can be seen from the direction of longitudinal spherical aberration / axial chromatic aberration, the chromatic aberration corresponding to different apertures in the central field of view is basically less than 0.015, indicating that the projection lens 100 can correct spherical aberration well.

[0114] Please see Figure 5 As can be seen from the modulation transfer function (MTF) curve, the modulus values ​​corresponding to different image heights are generally greater than 0.4 when the spatial frequency is at its maximum, indicating that the projection lens 100 has good projection performance.

[0115] Please see Figure 6 As can be seen from the principal ray incident angle curve, the magnitude of the principal ray incident angle on the image plane corresponding to different image heights is relatively stable, indicating that the projection lens 100 has good projection performance.

[0116] The projection lens 100 provided in Embodiment 1 of this application can have better optical performance by adopting the above parameters. The optical power of the projection lens 100 is reasonably allocated, and the space utilization rate is improved. This is beneficial to improving comfort and portability when the projection lens 100 is applied to a near-eye display device.

[0117] Example 2

[0118] Please see Figure 7 In Embodiment 2 of this application, the first lens 10 and the second lens 20 are bonded together, that is, the first image side S2 and the second object side S3 are bonded together. The reflecting lens 50 is bonded to the transmission plane of the plane lens 40, and the other side of the plane lens 40 is bonded to the second side S8 of the beam splitter 30. The reflecting surface S6 is an aspherical curved surface.

[0119] The parameters of each optical surface in the projection lens 100 of this embodiment are shown in Table 3.

[0120] Table 3 Optical surface parameters of projection lens 100

[0121]

[0122]

[0123] In Table 3, the aspherical surface S6 follows the following formula for its sagitta:

[0124] .

[0125] The thickness of the reflecting surface S6 is the thickness of the air gap between the reflecting surface S6 and the transmission plane S7. The coefficient of the aspherical surface of the reflecting surface S6 is shown in Table 4.

[0126] Table 4 Aspherical coefficients of reflective surface S6

[0127]

[0128] The optical parameters of the projection lens 100 in this embodiment are shown in Table 5.

[0129] Table 5 Optical parameters of projection lens 100

[0130]

[0131] In this embodiment, the IMH is 3.05mm, the ratio of the modulation surface S15 is 4:3, the FOV of the projection lens 100 is 41.8°, and the effective focal length f of the projection lens 100 is 8.0mm.

[0132] Please see Figure 8 As can be seen from the astigmatism curve, the offset of the projection lens 100 in Embodiment 2 of this application is basically below 0.015mm. As can be seen from the distortion curve, the distortion of the projection lens 100 is controlled within 0.5%. This indicates that the projection lens 100 in Embodiment 2 of this application, by setting the reflective surface S6 as an aspherical surface and using the parameters shown in Table 4, can better correct astigmatism and distortion.

[0133] Please see Figure 9 As can be seen from the magnification chromatic aberration curve, the chromatic aberration at different image heights is relatively small, and can be basically controlled below 0.00085mm. This indicates that the projection lens 100 of this embodiment can better correct chromatic aberration than the projection lens 100 of Embodiment 1.

[0134] Please see Figure 10 As can be seen from the longitudinal spherical aberration / axial chromatic aberration direction, the chromatic aberration corresponding to different apertures in the central field of view is basically less than 0.005, indicating that the projection lens 100 of this embodiment can better correct spherical aberration than the projection lens 100 of Embodiment 1.

[0135] Please see Figure 11 As can be seen from the modulation transfer function (MTF) curve, the modulus values ​​corresponding to different image heights are generally greater than 0.6 when the spatial frequency is at its maximum, indicating that the projection lens 100 of this embodiment has better projection performance than the projection lens 100 of Embodiment 1.

[0136] Please see Figure 12 As can be seen from the principal ray incident angle curve, the magnitude of the principal ray incident angle on the image plane corresponding to different image heights is relatively stable, indicating that the projection lens 100 has good projection performance.

[0137] The projection lens 100 provided in Embodiment 2 of this application can further improve the optical performance of the projection lens 100 by adopting the above parameters, thereby better allocating the optical power of the projection lens 100 and improving the space utilization rate. This is beneficial to improving comfort and portability when the projection lens 100 is applied to a near-eye display device.

[0138] Please see Figure 13This application embodiment also provides a near-eye display device 200, which includes an optical engine 210, a projection lens 100 as described in the above embodiment, and an imaging module 230. The optical engine 210 is used to emit light source light L1 to the projection lens 100, the projection lens 100 is used to emit image light L2 to the imaging module 230, and the imaging module 230 is used to transmit the image light L2 to the user's eye E, so that the user can see the image.

[0139] Specifically, in this embodiment, the near-eye display device 200 can be an augmented reality display device, that is, the user can simultaneously see the image formed by the image light L2 projected by the projection lens 100 on the imaging module 230, and see the natural scene outside through the imaging module 230. In other embodiments, the near-eye display device 200 can also be a virtual reality display device or a mixed reality display device, and this application does not limit it in this way.

[0140] The imaging module 230 may specifically include an input grating, an optical waveguide, and an output grating (not shown in the figure). The input grating is used to couple the image light L2 into the optical waveguide, the optical waveguide is used to transmit the image light L2 to the output grating, and the output grating is used to couple the image light L2 out of the optical waveguide, thereby incident on the eye E. In other embodiments, the imaging module 230 may also be other structures, such as a birdbath structure or a prism structure, etc. This application does not limit this.

[0141] The near-eye display device 200 provided in this application embodiment, by adopting the projection lens 100 in the above embodiment, can reduce the size while having high light efficiency, thereby making the near-eye display device 200 have better portability and comfort.

[0142] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A projection lens characterized in that, The projection lens comprises, from the object side to the image side, a first lens, a second lens, a light splitting prism, a flat lens, a reflecting lens, a third lens and a modulation chip. The light splitting prism is configured to receive and guide the light source light and the image light. The first lens and the second lens are arranged on a first side of the light splitting prism, the second lens is arranged between the first lens and the light splitting prism, and the first lens and the second lens are configured to receive and project the image light emitted from the light splitting prism. The first lens has a convex object side and a concave image side. The flat lens and the reflecting lens are arranged on a second side of the light splitting prism, the flat lens is arranged between the reflecting lens and the light splitting prism, and the reflecting lens is configured to reflect the image light. The third lens and the modulation chip are arranged on a third side of the light splitting prism, the third lens is arranged between the modulation chip and the light splitting prism, and the modulation chip is configured to receive the light source light and modulate the light source light into the image light before emitting the image light to the reflecting lens.

2. The projection lens of claim 1, wherein, The projection lens satisfies FOV / FNO>15.7, where FOV is the maximum field of view of the projection lens, and FNO is the relative aperture F number of the projection lens.

3. The projection lens of claim 1, wherein, The projection lens further comprises a diaphragm arranged on a side of the first lens away from the second lens.

4. The projection lens of claim 1, wherein, The first lens has a negative focal power, the second lens has a positive focal power, the reflecting lens has a positive focal power, and the third lens has a positive focal power.

5. The projection lens of claim 1, wherein, The reflecting surface is a spherical surface or a non-spherical curved surface.

6. The projection lens of claim 1, wherein, The first lens and the second lens are arranged in a spaced-apart manner or in a bonded manner.

7. The projection lens of claim 1, wherein, The projection lens satisfies -1.4°<CRA<1.4°, where CRA is the image principal ray incidence angle.

8. The projection lens of claim 1, wherein, The projection lens satisfies -0.35<f2 / f1<-0.23, where f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

9. The projection lens of claim 1, wherein, The projection lens satisfies 1.61<(f3 / f)<2.15, where f3 is the effective focal length of the reflecting lens, and f is the effective focal length of the projection lens.

10. The projection lens of claim 1, wherein, The projection lens satisfies f1(1 / R1_1-1 / R1_2)>2.12, where R1_1 is the curvature radius of the object side of the first lens, R1_2 is the curvature radius of the image side of the first lens, and f1 is the effective focal length of the first lens. The projection lens satisfies TTLV / IMH<3.4, where TTLV is the distance from the reflecting surface of the reflecting lens to the modulation surface of the modulation chip along the optical axis, and IMH is half of the diagonal length of the modulation surface.

11. The projection lens of claim 1, wherein, The projection lens satisfies TTLH / IMH<3.2, wherein TTLH is a distance between a first side of the first lens and a first side of the prism along a direction of an optical axis, and IMH is a half of a diagonal length of a modulation surface of the modulation chip.

12. The projection lens of claim 1, wherein, The projection lens satisfies BFL>1.15mm, wherein BFL is a distance between an image side of the third lens and the modulation surface of the modulation chip along the direction of the optical axis.

13. The projection lens of claim 1, wherein, The first lens satisfies f1 / D1>0.35, wherein f1 is an effective focal length of the first lens, and D1 is an effective aperture of the first lens.

14. The projection lens of claim 1, wherein, The third lens satisfies f6(1 / R6_1-1 / R6_2)>1.97, wherein f6 is an effective focal length of the third lens, R6_1 is a curvature radius of a first side of the third lens, and R6_2 is a curvature radius of an image side of the third lens.

15. A near-eye display device, comprising: The projection lens comprises: The projection lens according to any one of claims 1-14; An optical engine configured to emit light source light to the projection lens; An imaging module configured to receive image light emitted by the projection lens.

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