Optical imaging system

Abstract

The utility model belongs to the optical imaging field, and specifically relates to an optical imaging system comprising a first light source and a second light source; the preset optical device is arranged opposite to the first light source and the second light source, the preset optical device comprises a first optical effective surface, and the first light source and the second light source are respectively reflected and transmitted on the first optical effective surface; the first prism comprises a second optical effective surface which is arranged opposite to the first optical effective surface, the second optical effective surface is respectively opposite to the first surface and the second surface of the first prism, and a reflecting film is plated on the first surface; the light passing through the preset optical device penetrates through the second optical effective surface, is reflected by the reflecting film of the first surface, enters the second optical effective surface, is reflected by the second optical effective surface, and penetrates through the second surface to be emitted to the exit pupil position; the first light source forms a first image through the optical system; the second light source forms a second image through the optical system.

Description

Technical Field

[0001] The utility model belongs to the field of optical imaging, and particularly relates to an optical imaging system. Background Art

[0002] In the prior art, for an optical system, the larger the exit pupil diameter, the better the viewer's experience. However, the larger the exit pupil diameter, the higher the design difficulty. This is because when the exit pupil diameter is larger, the aperture of the lens is larger and the number of lenses is more. Considering the design difficulty of the lens arrangement, when the number of lenses is more, the occupied space of the formed optical system is larger. For application scenarios with limited space but wanting to achieve a large exit pupil, the difficulty coefficient is relatively large.

[0003] Reasonably arranging optical devices in a limited space or reducing the number of optical devices becomes a problem to be solved. Summary of the Utility Model

[0004] The utility model is precisely proposed based on the above-mentioned requirements of the prior art. The technical problem to be solved by the utility model is to provide an optical imaging system with a high space utilization rate while maintaining a large exit pupil diameter.

[0005] To solve the above problems, the technical solutions provided by the utility model include:

[0006] An optical imaging system is provided, including: a first light source for providing light; a second light source for providing light; a preset optical device oppositely arranged with the first light source and the second light source respectively, the preset optical device including a first optical effective surface, the light emitted by the first light source is incident on the first optical effective surface and undergoes reflection, and the light emitted by the second light source is incident on the first optical effective surface and undergoes transmission; a first prism including a second optical effective surface, a first surface and a second surface, the second optical effective surface is oppositely arranged with the first optical effective surface, and the second optical effective surface is respectively opposite to the first surface and the second surface, and a reflective film is plated on the first surface; the light passing through the preset optical device passes through the second optical effective surface and emits towards the first surface, after being reflected by the reflective film, it is incident on the second optical effective surface, and its incident angle is greater than the total internal reflection angle of the first prism, so that the light is reflected on the second optical effective surface, and the reflected light passes through the second surface and emits towards the exit pupil position; the light emitted by the first light source forms a first image at the exit pupil position after passing through the preset optical device and the first prism; the light emitted by the second light source forms a second image at the exit pupil position after passing through the preset optical device and the first prism, and the focal plane depths of the first image and the second image are different.

[0007] Through the above settings, it is possible to ensure that the optical imaging system has a large exit pupil diameter while minimizing the space occupied by the optical imaging system. Only a prism is used to simultaneously achieve the light path changes of transmission and reflection. Specifically, by setting the angle of incidence on the prism, a folded and hybrid optical path structure can be realized, enabling reflection to be completed by the prism without the need for other large-space-occupying optical devices. The total internal reflection of the prism reduces the coating process, thereby saving manufacturing costs and reducing process difficulty.

[0008] Preferably, the preset optical device is a beam splitter; the light emitted by the first light source enters the first prism after being reflected by the beam splitter; the light emitted by the second light source enters the first prism after passing through the beam splitter.

[0009] Preferably, the preset optical device includes a second prism and a third prism; the first light source is disposed opposite to the second prism, and the second light source is disposed opposite to the third prism; the second prism includes a second optical effective surface, a first surface, and a second surface; the first surface is disposed opposite to the first light source, the first optical effective surface is disposed opposite to the second light source, and the first optical effective surface is disposed opposite to the first surface and the second surface respectively; the light emitted by the first light source passes through the first surface and enters the second prism, and is incident on the first optical effective surface. The incident angle on the first optical effective surface is greater than the total internal reflection angle of the first prism so that the light is reflected on the first optical effective surface, and the reflected light passes through the second surface and exits from the first prism; the third prism is disposed opposite to the second prism and is symmetric with respect to a plane parallel to the first optical effective surface. The third prism is used to compensate the optical path of the light emitted by the second light source; the light emitted by the second light source passes through the third prism and then through the second prism in sequence and is emitted toward the first prism. Among them, for the light emitted by the second light source and finally exiting from the exit pupil position, the optical path difference is within 6 μm.

[0010] Through the above settings, the second prism and the third prism are used to complete the transmission and reflection of light, and there is no light loss when the light is incident on the beam splitter during the light propagation. Therefore, the light flux in the optical imaging system can be effectively guaranteed. In addition, when light passes through air and a prism, due to the different refractive indices, the equivalent optical paths are different for the same thickness of air and prism. When the optical path difference of the light beams at different apertures in the same field of view is larger, the aberration will be larger, resulting in a lower imaging quality. Therefore, a third prism is set to compensate the optical path of the light emitted by the second light source, making the optical paths of the light at different apertures in the same field of view close to each other, thereby reducing the aberration and improving the imaging quality.

[0011] Preferably, the beam splitter is a planar beam splitter with a splitting ratio of 1:1.

[0012] Through the above settings, the first light source and the second light source can be coupled into the first prism simultaneously, ensuring that the energy of the two light sources entering the optical imaging system is consistent.

[0013] Preferably, taking the center of the exit pupil of the optical imaging system as the origin O, the direction from the exit pupil horizontally towards the first prism as the Z-axis, the vertically upward direction as the Y-axis, and one of the directions perpendicular to the YOZ plane as the X-axis to form a local coordinate system. The distance range from the origin to the second surface of the first prism is 10 mm to 20 mm; the Y eccentricity range of the center of the second surface is -3 mm to 3 mm, and the tilt angle range with the XOY plane is 5° to 25°; the Z eccentricity range of the center of the second optically effective surface of the first prism is 20 mm to 30 mm, the Y eccentricity range is -3 mm to 3 mm, and the tilt angle range with the XOY plane is 35° - 55°; the Z eccentricity range of the center of the first surface of the first prism is 21 mm to 31 mm, the Y eccentricity range is 6 mm - 16 mm, and the tilt angle range with the XOY plane is 67° - 87°.

[0014] Preferably, the Z eccentricity range of the center of the beam splitter is 28 mm to 38 mm, the Y eccentricity range is -7 mm to 3 mm, and the tilt angle range with the XOY plane is 5° - 25°.

[0015] Preferably, the Z eccentricity range of the center of the second light source surface is 30 mm - 40 mm; the Y eccentricity range is -13 mm to -3 mm, and the tilt angle range with the XOY plane is 65° - 85°; the Z eccentricity range of the center of the first light source surface is 22 mm - 32 mm; the Y eccentricity range is -11 mm to -1 mm, and the tilt angle range with the XOY plane is 35° - 55°.

[0016] Preferably, the depth of focus range of the first image and the second image is -1000 mm to +200 mm. One of the first image or the second image will fall on the retina of the viewer, and the other image will fall in front of the retina of the viewer.

[0017] Preferably, the focal length of the first prism is 15 mm - 24 mm.

[0018] Preferably, the diagonal field of view of the optical imaging system optical path is not less than 40°, and the horizontal field of view angle is greater than or equal to 33°; the exit pupil diameter of the optical imaging system is greater than or equal to 8 mm.

[0019] Compared with the prior art, through the relative positional relationship of each optical device, the present utility model can meet the requirements of both transmission and reflection only by setting a prism, without adding other optical devices, thereby reducing the coating process, manufacturing cost and process difficulty. In addition, the optical imaging system involved in the present application can form a relatively large exit pupil size, thus bringing a good visual experience to the viewer. At the same time, it occupies a small space and can be flexibly adapted to various scenarios. In addition, when the focal plane depths of the first image and the second image are different, myopic defocus stimulation can be generated. While ensuring that one of the images falls on the retina, the other image falls in front of the retina, thereby stimulating the retina to produce a forward movement trend, and further inhibiting the elongation of the eye axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present specification. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of the optical path structure of an optical imaging system in an embodiment of the present utility model;

[0022] Figure 2 Schematic diagram of the imaging optical path structure of the first light source in an embodiment of the present utility model;

[0023] Figure 3 Schematic diagram of the imaging optical path structure of the second light source in an embodiment of the present utility model;

[0024] Figure 4 Schematic diagram of the local coordinate system established in an embodiment of the present utility model;

[0025] Figure 5 Schematic diagram of another optical imaging system structure in an embodiment of the present utility model;

[0026] Figure 6 Schematic diagram of the structure of a feasible implementation system in an embodiment of the present utility model;

[0027] Figure 7 Schematic diagram of the sampling field MTF curve formed by the first light source in the feasible implementation manner of the embodiment;

[0028] Figure 8 Schematic diagram of the sampling field MTF curve formed by the second light source in the feasible implementation manner of the embodiment;

[0029] Figure 9 Schematic diagram of the distortion grid of the first image in the feasible implementation manner of the embodiment;

[0030] Figure 10 Schematic diagram of the distortion grid of the second image in a feasible implementation manner of the embodiment

[0031] Reference numerals:

[0032] 1. First light source; 2. Second light source; 3. Preset optical device; 4. First prism; 5. Beam splitter; 6. First optically effective surface; 7. First surface; 8. Second surface; 9. Second prism; 10. First surface; 11. Second surface; 12. Exit pupil; 13. Second optically effective surface; 14. Third prism Detailed implementation manners

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application

[0034] In the description of the embodiments of the present utility model, it should be noted that unless otherwise clearly defined and limited, the term "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection. It may be a mechanical connection or an electrical connection. It may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances

[0035] The terms "top", "bottom", "above...", "below", and "on..." described throughout the text are relative positions of the components of the device, such as the relative positions of the top and bottom substrates inside the device. It can be understood that the device is multifunctional and has nothing to do with its orientation in space

[0036] To facilitate the understanding of the embodiments of the present application, the following will further explain with specific examples in conjunction with the accompanying drawings. The examples do not constitute a limitation to the embodiments of the present application

[0037] This embodiment provides an optical imaging system, as Figures 1-6 shown

[0038] The optical imaging system includes a light source, a preset optical device 3, and a first prism 4

[0039] The light source includes a first light source 1 and a second light source 2, and the light source emits light to provide a light source for the optical imaging system

[0040] The light source can be a display, a lamp bead, or a lamp bead matrix formed by arranging lamp beads to display a specific pattern, and the light source can be adapted according to requirements.

[0041] The preset optical device 3 is disposed opposite to the first light source 1 and the second light source 2 respectively. The preset optical device 3 includes a first optically effective surface 6. The light emitted by the first light source 1 is incident on the first optically effective surface 6 and is reflected, and the light emitted by the second light source 2 is incident on the first optically effective surface 6 and is transmitted.

[0042] The preset optical device 3 can be a beam splitter 5, or a combination of a second prism 9 and a third prism 14. Different optical devices have different light processing methods, which will be described in detail below for the two cases.

[0043] When the preset optical device 3 is a beam splitter 5, as Figure 1 shown:

[0044] The beam splitter 5 can output the incident light in two different ways. Specifically, a part of the light incident on the beam splitter 5 will be refracted, that is, it will be output from the other side of the beam splitter 5 except the incident surface, and its output direction has a certain deviation from the incident direction; another part of the light incident on the beam splitter 5 will be reflected, that is, it will change direction and be output from the incident surface.

[0045] As Figure 2 shown, the light emitted by the first light source 1 is incident on the beam splitter 5, and the light reflected by the beam splitter 5 will participate in the propagation of the optical path of the optical imaging system. That is to say, the light reflected by the first light source 1 through the beam splitter 5 is effective light, and the light refracted by the first light source 1 through the beam splitter 5 is ineffective light, and the ineffective light will be consumed and does not participate in the formation of the final first image.

[0046] As Figure 3 shown, the light emitted by the second light source 2 is incident on the beam splitter 5, and the light transmitted by the beam splitter 5 will participate in the propagation of the optical path of the optical imaging system. That is to say, the light transmitted by the second light source 2 through the beam splitter 5 is effective light, and the light reflected by the second light source 2 through the beam splitter 5 is ineffective light, and the ineffective light will be consumed and does not participate in the formation of the final second image.

[0047] Since both the first light source 1 and the second light source 2 need to pass through the beam splitter 5, in order to ensure that there is no large difference in the light flux of the finally formed images, the splitting ratio of the beam splitter 5 is set to 1:1, that is, 50% of the light incident on the beam splitter 5 will be reflected, and the other 50% will be refracted.

[0048] When the preset optical device 3 is a combination of a second prism 9 and a third prism 14, as Figure 5 shown:

[0049] The second prism 9 includes a first surface 7, a first optically effective surface 6, and a second surface 8. The first surface 7 is disposed opposite to the first light source 1, the first optically effective surface 6 is disposed opposite to the first surface 7, and the second surface 8 is disposed opposite to the first optically effective surface 6. When light is incident into the prism and hits a certain surface of the first prism 4, if the incident angle is greater than the total internal reflection angle of the prism, the light will be reflected on that surface.

[0050] The light emitted by the first light source 1 transmits through the first surface 7 and enters the second prism 9, and is incident on the first optically effective surface 6, where its incident angle is greater than the total internal reflection angle arcsin(1 / n) of the second prism 9, where n is the refractive index of the material of the second prism 9, such that the light is reflected on the first optically effective surface 6, and the reflected light is emitted towards the second surface 8 and outputs outside the second prism 9 through the transmission of the second surface 8.

[0051] The third prism 14 is disposed opposite to the second prism 9, and the two are symmetric with respect to a plane parallel to the first optically effective surface 6. The third prism is used to compensate the optical path of the light emitted by the second light source.

[0052] When light passes through air and a prism, due to the different refractive indices, the equivalent optical paths are different for the same thickness of air and prism. To compensate for the optical path, the third prism 14 is provided.

[0053] The light emitted by the second light source 2 transmits through the third prism 14, then transmits through the first optically effective surface 6, emits towards the second surface 8 and passes through the second surface 8, and outputs outside the second prism 9. When the light emitted by the second light source is incident on the second surface, the optical path difference is within the threshold range. Further, when the light emitted by the second light source is incident on the second surface, the optical path difference is 0. Through the above settings, it is ensured that the optical paths of all the light rays in the same field of view are close, so that the aberration of the final image is small and the imaging has better quality.

[0054] The first prism 4 includes a second optically effective surface 13, a first surface 10, and a second surface 11.

[0055] The second optically effective surface 13 is disposed opposite to the first optically effective surface 6, such that the light output from the preset optical device 3 enters the first prism 4 through the second optically effective surface 13.

[0056] The first surface 10 is disposed opposite to the second optically effective surface 13, and a total reflection film is provided on the second optically effective surface 13. The light passing through the second optically effective surface 13 is incident on the first surface 10 and is reflected by the total reflection film thereon and then emitted.

[0057] The light rays emitted through the first surface 10 will be incident on the second optically effective surface 13, and the incident angle this time is greater than the total internal reflection angle arcsin(1 / n') of the first prism 4, where n' is the refractive index of the material of the first prism 4, so that the light rays are reflected on the second optically effective surface 13.

[0058] The second surface 11 is disposed opposite to the second optically effective surface 13. The light rays reflected by the second optically effective surface 13 will be incident on the second surface 11 and transmit out of the first prism 4 from the second surface 11, and emit towards the position of the exit pupil 12 to form a corresponding image.

[0059] The light rays emitted by the first light source 1 form a first image through the above optical imaging system, and the light rays emitted by the second light source 2 form a second image through the above optical imaging system. Specifically: The light rays emitted by the first light source 1 are reflected by the first optically effective surface 6 of the preset optical device 3 and then incident into the first prism 4. After passing through the transmission of the second optically effective surface 13, the reflection of the first surface 10, the reflection of the second optically effective surface 13, and the transmission of the second surface 11 in sequence, a first image is formed at the position of the exit pupil 12. The light rays emitted by the second light source 2 are transmitted through the first optically effective surface 6 of the preset optical device 3 and then incident into the first prism 4. After passing through the transmission of the second optically effective surface 13, the reflection of the first surface 10, the reflection of the second optically effective surface 13, and the transmission of the second surface 11 in sequence, a second image is formed at the position of the exit pupil 12. Among them, the first image has a first focal plane depth, and the second image has a second focal plane depth. When the first focal plane depth and the second focal plane depth are different, the first image or the second image can fall on the viewer's retina, and the other image will fall in front of the viewer's retina. At this time, myopic defocus will be formed in the viewer's eyes, so that when the viewer can clearly see one image, the other image located in front of the retina has a tendency to drive the retina to move forward, thereby effectively suppressing the elongation of the eye axis.

[0060] To further illustrate the relative positional relationship of the optical devices in the entire optical imaging system when the preset optical device 3 is a beam splitter 5, as Figure 4 shown, taking the center of the exit pupil 12 of the optical imaging system as the origin O, the direction of the exit pupil 12 horizontally towards the first prism 4 as the Z axis, the vertically upward direction as the Y axis, and one of the directions perpendicular to the YOZ plane as the X axis, a local coordinate system is formed.

[0061] The distance range from the origin to the second surface 11 of the first prism 4 is 10 mm to 20 mm; the Y eccentricity range of the center of the second surface 11 is -3 mm to 3 mm, and the inclination angle range with the XOY plane is 5° to 25°.

[0062] The Z eccentricity range at the center of the second optically effective surface 13 of the first prism 4 is 20 mm to 30 mm, the Y eccentricity range is -3 mm to 3 mm, and the tilt angle range with the XOY plane is 35° - 55°.

[0063] The Z eccentricity range at the center of the first surface 10 of the first prism 4 is 21 mm to 31 mm, the Y eccentricity range is 6 mm - 16 mm, and the tilt angle range with the XOY plane is 67° - 87°.

[0064] The Z eccentricity range at the center of the beam splitter 5 is 28 mm to 38 mm, the Y eccentricity range is -7 mm to 3 mm, and the tilt angle range with the XOY plane is 5° - 25°.

[0065] The Z eccentricity range at the center of the surface of the second light source 2 is 30 mm - 40 mm; the Y eccentricity range is -13 mm to -3 mm, and the tilt angle range with the XOY plane is 65° - 85°.

[0066] The Z eccentricity range at the center of the surface of the first light source 1 is 22 mm - 32 mm; the Y eccentricity range is -11 mm to -1 mm, and the tilt angle range with the XOY plane is 35° - 55°.

[0067] In the above optical imaging system, the focal length of the first prism 4 is 15 mm - 24 mm, the formed diagonal field of view is not less than 40°, the field of view angle in the horizontal direction is greater than or equal to 33°; the diameter of the exit pupil 12 of the optical imaging system is greater than or equal to 8 mm. The focal plane depth ranges of the first image and the second image are -1000 mm to -∞ and +200 mm to +∞.

[0068] For the convenience of understanding the overall technical solution, a specific and feasible real-time method will be given here. In this real-time method, the preset optical device 3 is the beam splitter 5, and the formed optical imaging system is as Figure 6 shown. The field of view angles of the display optical paths corresponding to the first image and the second image are both 40°, the diameter of the exit pupil 12 is 8 mm, the first focal plane depth is -3000 mm; the second focal plane depth is 1000 mm, and the system focal length is 19.4 mm. The optical system parameters of the display optical path for forming the first image and the optical system parameters of the display optical path for forming the second image are shown in Table 1 and Table 2 respectively, and the corresponding free-form surface coefficients of the display optical path are shown in Table 3.

[0069] Table 1 Optical System Parameters of the Display Optical Path for Forming the First Image

[0070]

[0071]

[0072] Among the above surfaces, the surfaces that form the freeform surface satisfy the equation: c is the reciprocal of the radius of curvature, r is the radial distance of a point on the surface, k is the conic constant, and Ci is the coefficient of the higher-order term.

[0073] Table 2 Optical system parameters of the display optical path for forming the second image

[0074]

[0075]

[0076] Among them, 200 is the first image, 201 is the exit pupil, 202 is the second surface, 203 is the second optically effective surface, 204 is the first surface, 205 is the first optically effective surface, 206 is the cover plate surface in front of the light-emitting surface of the first light source, 207 is the light-emitting surface of the first light source, 208 is the cover plate surface in front of the light-emitting surface of the second light source, 209 is the light-emitting surface of the second light source, and 200’ is the second image.

[0077] Table 3 Coefficients of the freeform surface of the optical path

[0078]

[0079]

[0080] In the above specific implementation manner, the sampling field MTF curve, that is, the Modulation Transfer Function, which can form the first image and the second image, is as Figure 7 and Figure 8 shown. The MTF curve is a term in optical engineering and is often used to evaluate the performance of an optical system. The abscissa represents the sampling frequency in the image space, the ordinate represents the contrast, F1 to F9 are the sampling fields used to evaluate the display quality of the system, and X and Y represent two directions respectively. The MTF values of each field at 30 lp / mm are higher than 0.4, indicating that the above system has excellent imaging. As Figure 9 and Figure 10 shown, they are respectively the comparison of the distortion grid of the focal plane where the first image and the second image are located with the ideal focal plane. The optical distortion of the above wearable optical system is less than 8%. That is, the optical system formed by the above implementation manner has relatively stable performance and can ensure the imaging quality.

[0081] The above specific implementation manner further details the purpose, technical solution, and beneficial effects of the present application. It should be understood that the above is only the specific implementation manner of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An optical imaging system, characterized in that: include: A first light source provides light; A second light source, providing light; A preset optical device is respectively arranged opposite to the first light source and the second light source, and the preset optical device includes a first optically effective surface, and the light emitted by the first light source is reflected when incident on the first optically effective surface, and the light emitted by the second light source is transmitted when incident on the first optically effective surface; A first prism comprises a second optically effective surface, a first surface and a second surface, wherein the second optically effective surface is arranged opposite to the first optically effective surface, and the second optically effective surface is respectively opposite to the first surface and the second surface, and a reflective film is plated on the first surface; light passing through a preset optical device passes through the second optically effective surface, is emitted toward the first surface, and after being reflected by the reflective film, is incident on the second optically effective surface, and its incident angle is greater than the total internal reflection angle of the first prism, so that the light is reflected on the second optically effective surface, and the reflected light passes through the second surface and is emitted toward the exit pupil position; After the light emitted by the first light source passes through the preset optical device and the first prism, a first image is formed at the exit pupil position; after the light emitted by the second light source passes through the preset optical device and the first prism, a second image is formed at the exit pupil position.

2. The optical imaging system according to claim 1, characterized in that: The preset optical device is a beam splitter; The light emitted by the first light source is reflected by the beam splitter and then output into the first prism; The light emitted by the second light source is transmitted through the beam splitter and then outputted into the first prism.

3. The optical imaging system according to claim 1, characterized in that: The preset optical device includes a second prism and a third prism; the first light source is arranged opposite to the second prism, and the second light source is arranged opposite to the third prism; The second prism includes a second optically effective surface, a first surface, and a second surface; The first surface is arranged opposite to the first light source, the first optically effective surface is arranged opposite to the second light source, and the first optically effective surface is arranged opposite to the first surface and the second surface respectively; Light emitted by the first light source is transmitted through the first surface into the second prism and incident on the first optically effective surface. The incident angle on the first optically effective surface is greater than the total internal reflection angle of the first prism so that the light is reflected on the first optically effective surface, and the reflected light is transmitted through the second surface and emitted from the first prism; The third prism is arranged opposite to the second prism and is symmetrical with a plane parallel to the first optical effective surface; the third prism is used to compensate for the optical path difference; The light emitted by the second light source is sequentially transmitted through the third prism and the second prism and then emitted toward the first prism. The optical path difference of the light emitted by the second light source and finally emitted from the exit pupil position is within 6 um.

4. The optical imaging system according to claim 2, characterized in that: The beam splitter is a plane beam splitter with a beam splitting ratio of 1:

1.

5. The optical imaging system according to claim 2 or 4, characterized in that: The exit pupil center of the optical imaging system is taken as the origin O, the direction of the exit pupil toward the first prism is taken as the Z axis, the vertical upward direction is taken as the Y axis, and one of the directions perpendicular to the YOZ plane is taken as the X axis to form a local coordinate system. The distance from the origin to the second surface of the first prism ranges from 10 mm to 20 mm; the Y eccentricity range of the center of the second surface ranges from -3 mm to 3 mm, and the inclination angle range between the center and the XOY plane ranges from 5° to 25°; The center of the second optically effective surface of the first prism has a Z eccentricity range of 20 mm to 30 mm, a Y eccentricity range of -3 mm to 3 mm, and an inclination angle range of 35° to 55° with respect to the XOY plane; The Z eccentricity range of the center of the first surface of the first prism is 21 mm to 31 mm, the Y eccentricity range is 6 mm to 16 mm, and the inclination angle range between the center and the XOY plane is 67° to 87°.

6. The optical imaging system according to claim 5, characterized in that: The Z eccentricity range of the center of the beam splitter is 28 mm to 38 mm, the Y eccentricity range is -7 mm to 3 mm, and the inclination angle range between the center and the XOY plane is 5° to 25°.

7. The optical imaging system according to claim 5, characterized in that: The Z eccentricity range of the center of the second light source surface is 30mm to 40mm; the Y eccentricity range is -13mm to -3mm, and the inclination angle range with the XOY plane is 65° to 85°; The Z eccentricity range of the center of the surface of the first light source is 22 mm to 32 mm; the Y eccentricity range is -11 mm to -1 mm, and the inclination angle range with respect to the XOY plane is 35° to 55°.

8. The optical imaging system according to claim 1, characterized in that: The focal depth ranges of the first image and the second image are -1000mm to -∞ and +200mm to +∞. The first image or the second image will fall on the retina of the viewer, and the other image will fall in front of the retina of the viewer.

9. The optical imaging system according to claim 1, characterized in that: The focal length of the first prism is 15mm-24mm.

10. The optical imaging system according to claim 1, characterized in that: The diagonal field of view of the optical path of the optical imaging system is not less than 40°, and the horizontal field of view is greater than or equal to 33°; the exit pupil diameter of the optical imaging system is greater than or equal to 8mm.

Images