Visual optical system

Abstract

The invention belongs to the field of optical imaging, and particularly relates to a visual optical system comprising a first prism which comprises a first optical surface and is provided with a beam splitting film; the second optical surface is opposite to the first optical surface; the third optical surface is opposite to the second optical surface, and a reflecting film is arranged on the third optical surface; a light source disposed opposite the first optical surface; light is emitted from the light source to the first optical surface, penetrates through the first optical surface, enters the second optical surface at a first incidence angle, is reflected to the third optical surface, enters the second optical surface at a second incidence angle under the action of the reflecting film on the third optical surface, and is reflected to the first optical surface. The light reaches and penetrates through the second optical surface under the reflection effect of the first optical surface and is emitted towards an exit pupil; wherein the first incident angle and the second incident angle are both larger than or equal to arctan (1 / n), and n is the refractive index of the first prism material when the light wavelength is 586 nm.

Description

Technical Field

[0001] The invention belongs to the field of optical imaging, and in particular relates to a visual optical system. Background Art

[0002] As an off-axis element, the free-form surface prism is suitable for constructing a lightweight, wearable visual optical system. In the visual optical system in the prior art, the light source or image source is often located above the free-form surface prism, and the image is formed on the side of the free-form surface prism, which makes the system height and width large, that is, the volume size of the entire visual optical system is large. When worn, it exerts great pressure on the supporting parts such as the head, and the user experience is poor. Summary of the invention

[0003] The present invention is proposed based on the above-mentioned requirements of the prior art. The technical problem to be solved by the present invention is to provide a visual optical system to reduce the system size and improve the user experience.

[0004] In order to solve the above problems, the technical solution provided by the present invention includes:

[0005] Provided is a visual optical system, comprising: a first prism, comprising a first optical surface, on which a dichroic film is arranged; a second optical surface, arranged opposite to the first optical surface, and spaced apart from the first optical surface in a width direction; a third optical surface, arranged between the first optical surface and the second optical surface, and arranged opposite to the second optical surface, and a reflective film is arranged on the third optical surface; a light source, located outside the first prism, arranged opposite to the first optical surface, and spaced apart from the first optical surface in a width direction; an exit pupil, located on both sides of the light source in a width direction of the first prism; a visual optical path, formed between the light source, the first optical surface, and the second optical surface The light is emitted from the light source to the first optical surface, passes through the first optical surface under the action of the dichroic film, is incident on the second optical surface at a first incident angle and is reflected from the third optical surface, is incident on the second optical surface at a second incident angle and is reflected from the first optical surface under the action of the reflective film on the third optical surface, and then reaches and passes through the second optical surface under the reflection action of the dichroic film on the first optical surface and is emitted toward the exit pupil, forming an image with a focal plane depth greater than 1m at the exit pupil position; wherein the first incident angle and the second incident angle are both greater than or equal to arctan(1 / n), wherein n is the refractive index of the first prism material when the wavelength of the light is 586nm.

[0006] The light source is arranged in the width direction of the first prism to lower the height of the visual optical system, a dichroic film is arranged on the first optical surface of the first prism, and a reflective film is arranged on the third optical surface, while ensuring the size of the incident angle onto the second optical surface, thereby achieving multiple folding and reflection of the light in the first prism, thereby effectively reducing the volume of the visual optical system, achieving miniaturization, and being convenient for use in wearable or VR devices, thereby improving the user experience.

[0007] Preferably, the splitting ratio of the splitter film is 1:1.

[0008] Through the above, imaging is ensured and the utilization rate of light is improved.

[0009] Preferably, a coordinate system is established with the center of the exit pupil position as the origin O of the coordinate system, the direction parallel to the optical axis and toward the first prism as the Z axis, the direction perpendicular to the Z axis and vertically upward as the Y axis, and the direction perpendicular to the YOZ plane as the X axis; the Z eccentricity range of the center of the first optical surface is 17mm~24mm, the Y eccentricity range is -2mm~+1mm, and the inclination angle range around the XOY plane is -32°~-24°; the Z eccentricity range of the center of the second optical surface is 1mm~5mm, and the inclination angle range around the XOY plane is ±5°; the second optical surface is 13mm~20mm away from the exit pupil center along the Z axis; the Z eccentricity range of the center of the third optical surface is 17mm~24mm, the Y eccentricity range is -2mm~+1mm, and the inclination angle range around the XOY plane is -32°~-24°; the Z eccentricity range of the center of the second optical surface is 1mm~5mm, and the inclination angle range around the XOY plane is ±5°; the distance between the second optical surface and the exit pupil center along the Z axis is 13mm~20mm; the Z eccentricity range of the center of the third optical surface is 17mm~24mm, the Y ... The range is 16.6mm~23.6mm, the Y eccentricity range is 9mm~17mm, and the inclination angle range around the XOY plane is 46°~56°; the Z eccentricity range of the center of the light emitting surface of the light source is 17mm~27mm, the Y eccentricity range is -1mm~+1mm, and the inclination angle range around the XOY plane is 46°~56°; the diagonal field of view of the focal plane display light path of the formed visual optical system is not less than 35°; the field of view angle in the horizontal direction should be at least greater than 30°; the exit pupil diameter of the system is at least greater than 7mm; the focal plane depth range of the system is: 100mm~100000mm; the focal length range of the first prism 2 in the system is: 13mm~21mm.

[0010] Preferably, the first optical surface at least partially covers the plane where the light source is located in a direction perpendicular to the width.

[0011] By setting the width of the visual optical system to be limited, the miniaturization of the overall system is ensured.

[0012] Preferably, the first prism is in a triangular prism-like shape.

[0013] Preferably, the visual optical system also includes a second prism, which is arranged between the light source and the first prism, and the second prism includes a first optically effective surface and a second optically effective surface, the first optically effective surface is arranged opposite to the light source, and the second optically effective surface is arranged opposite to the first prism, and the light emitted by the light source passes through the first optically effective surface and the second optically effective surface in sequence and is incident on the first prism.

[0014] Preferably, a coordinate system is established with the center at the exit pupil position as the origin of the coordinate system, the direction parallel to the optical axis and toward the first prism as the Z axis, the direction perpendicular to the Z axis and vertically upward as the Y axis, and the direction perpendicular to the YOZ plane as the X axis; the Z eccentricity range of the center of the first optically effective surface is 19mm~27mm, the Y eccentricity range is -1mm~+1mm, and the inclination angle range around the XOY plane is 38°~48°; the Z eccentricity range of the center of the light emitting surface of the light source is 20mm~28mm, the Y eccentricity range is -2mm~+2mm, and the inclination angle range around the XOY plane is 47°~57°.

[0015] Preferably, the second optically effective surface is disposed in contact with the first optical surface.

[0016] Preferably, the first optical surface and the first optically effective surface satisfy an XY polynomial, which is expressed as: c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, C i are high-order coefficients, m and n are expressed as power orders of polynomials, the radius of curvature of the first optical surface is -137.8, the refractive index is 1.53, the Abbe number is 55.9, the Y eccentricity is 0.15 mm, the Z eccentricity is 20.67 mm, and the inclination angle around the XOY plane is -25.39°; the radius of curvature of the second optically effective surface is -89.1, the Y eccentricity is -0.13 mm, the Z eccentricity is 22.19 mm, and the inclination angle around the XOY plane is -42.83°.

[0017] Preferably, when the light emitted by the light source is incident on the second optically effective surface, the corresponding incident angle is less than arctan (1 / n).

[0018] Compared with the prior art, the present invention proposes a visual optical system based on a free-form surface prism, wherein the image source is located on one side of the prism in the width direction, which can reduce the height of the system and is conducive to the integrated design of the system; the multiple folding light path design ensures that the system has a minimum volume; the total internal reflection property of the prism is used twice, which effectively improves the light energy utilization rate of the system. In addition, a second prism is set between the light source and the first prism to correct the off-axis aberration, thereby improving the imaging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of this specification 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 recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0020] Figure 1 A schematic diagram of viewing a visual optical system in an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of the optical path structure of the visual optical system in an embodiment of the present invention;

[0022] Figure 3 Schematic diagram of the propagation of the upper boundary light beam emitted from the upper edge of the light source in an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of the propagation of the lower boundary light beam emitted from the upper edge of the light source in an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the propagation of the upper boundary light beam emitted from the lower edge of the light source in an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of the propagation of the lower boundary light beam emitted from the lower edge of the light source in an embodiment of the present invention;

[0026] Figure 7 is a schematic diagram of establishing a coordinate system in a visual optical system in an embodiment of the present invention;

[0027] Figure 8 A schematic diagram of an optical path of a visual optical system according to a feasible implementation mode in an embodiment of the present invention;

[0028] Fig. 9 This is a sampled field of view MTF curve of a visual optical system in a feasible implementation mode in an embodiment of the present invention;

[0029] Fig.10 A schematic diagram of a distortion grid of a visual optical system in a feasible implementation mode in an embodiment of the invention;

[0030] Fig.11 It is another optical path structure schematic diagram of the visual optical system in an embodiment of the present invention;

[0031] Fig.12 is a schematic diagram of establishing a coordinate system in another visual optical system in an embodiment of the present invention;

[0032] Fig.13A schematic diagram of a distortion grid of a visual optical system in another feasible implementation mode in an embodiment of the invention;

[0033] Fig.14 This is a sampled field MTF curve of a visual optical system in another feasible implementation manner in an embodiment of the present invention;

[0034] Fig.15 It is a schematic diagram of a distortion grid of a visual optical system in another feasible implementation manner in an embodiment of the invention.

[0035] Reference numerals:

[0036] 1. Light source; 2. First prism; 3. First optical surface; 4. Second optical surface; 5. Third optical surface; 6. Second prism; 7. First optically effective surface; 8. Second optically effective surface; 9. Exit pupil. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0038] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connected" should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integral connection, which can be a mechanical connection, or an electrical connection, which can be a direct connection, or can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The terms "top", "bottom", "above", "lower", and "on" used throughout the description are relative to the relative positions of components of a device, such as the relative positions of the top and bottom substrates within a device. It is understood that devices are multifunctional regardless of their orientation in space.

[0040] To facilitate understanding of the embodiments of the present invention, specific embodiments will be further explained below in conjunction with the accompanying drawings. The embodiments do not constitute a limitation on the embodiments of the present invention.

[0041] This embodiment provides a visual optical system, such as Figure 1-Figure 15 shown.

[0042] like Figure 1 and Figure 2As shown, the visual optical system includes a light source 1 and a first prism 2.

[0043] The light source 1 provides a light source for the visual optical system. Further, the light source 1 is a display.

[0044] The first prism 2 is disposed opposite to the light source 1. The first prism 2 comprises a first optical surface, a second optical surface 4 and a third optical surface 5. The first prism 2 and the light source 1 are disposed adjacent to each other along a width direction of the first prism 2.

[0045] The first optical surface is arranged opposite to the light source 1, and a dichroic film is coated on the first optical surface. The dichroic film can transmit a part of the light incident thereon, and reflect the remaining light for output. Furthermore, the dichroic film has a light splitting ratio of 1:1, that is, when the light is incident on one side of the dichroic film, half of the light can pass through the dichroic film in the form of transmission and be emitted from the other side of the dichroic film, and the other half of the light can be emitted from one side of the dichroic film in the form of reflection.

[0046] The light emitted by the light source 1 is incident on the first optical surface of the first prism 2, and a part of the light is output outside the visual optical system in the form of reflection. This part of the light no longer participates in the light propagation in the visual optical system and is invalid light. At the same time, a part of the light is output into the first prism 2 in the form of transmission and continues to propagate in the visual optical system, which is effective light.

[0047] The second optical surface 4 is arranged opposite to the first optical surface. The light transmitted through the first optical surface enters the first prism 2 and is emitted in the direction of the second optical surface 4. The first incident angle of the light incident on the second optical surface 4 satisfies the total internal reflection condition, that is, the angle of the incident angle is greater than arctan (1 / n), where n is the refractive index of the prism material when the wavelength of the light is 586nm.

[0048] The third optical surface 5 is arranged opposite to the second optical surface 4, and a reflective film is coated on the third optical surface 5, specifically, the reflective film is a total internal reflection film. After the total internal reflection of the second optical surface 4, the light will be incident on the third optical surface 5. Under the action of the reflective film, the light is reflected on the third optical surface 5 and emitted to the second optical surface 4. The second incident angle of the light incident on the second optical surface 4 still meets the condition of total internal reflection, so that the light is reflected on the second optical surface 4 and then emitted to the first optical surface. A part of the light incident on the first optical surface is emitted to the outside of the prism in the form of transmission and no longer participates in the light transmission of the visual optical system, and the other part is emitted to the second optical surface 4 in the form of reflection. After passing through the second optical surface 4, the light is emitted to the position of the exit pupil 9 and forms an image with a focal depth greater than 1m at the position of the exit pupil 9. In addition, the exit pupil 9 and the light source 1 are respectively located on both sides of the first prism 2.

[0049] Furthermore, for the two total internal reflections on the second optical surface 4 that meet the total internal reflection conditions:

[0050] like Figure 3 As shown, if the upper boundary light of the light beam emitted from the upper edge of the light source 1 can pass through the first optical surface, it will be θ 11 The incident angle is on the second optical surface 4, due to θ 11 ≥arctan(1 / n), reflected to the third optical surface 5, and then reflected by the third optical surface 5 to approximate θ 11 The light is incident on the second optical surface 4 at an angle, reflected toward the first optical surface, and after being reflected by the first optical surface, it is transmitted through the second optical surface 4 and emitted toward the exit pupil 9.

[0051] Similar, such as Figure 4 As shown, if the lower boundary light of the optical fiber bundle emitted from the upper edge of the light source 1 can pass through the first optical surface, it will be θ 31 The angle of incidence is on the second optical surface 4, θ 31 ≥arctan(1 / n), capable of reflection; after reflection from the third optical surface 5, with θ 32 The angle of incidence is on the second optical surface 4, and θ 32 ≥arctan(1 / n). To avoid redundant text, some descriptions of the propagation light paths will be omitted here and below.

[0052] like Figure 5 As shown, if the upper boundary light of the optical fiber bundle emitted from the lower edge of the light source 1 can pass through the first optical surface, it will be θ 21 The angle of incidence is on the second optical surface 4, θ 21≥arctan(1 / n), capable of reflection; after reflection from the third optical surface 5, with θ 22 The angle of incidence is on the second optical surface 4, and θ 22 ≥arctan(1 / n).

[0053] like Figure 6 As shown, if the upper boundary light of the optical fiber bundle emitted from the lower edge of the light source 1 can pass through the first optical surface, it will be θ 41 The angle of incidence is on the second optical surface 4, θ 41 ≥arctan(1 / n), capable of reflection; after reflection from the third optical surface 5, with θ 42 The angle of incidence is on the second optical surface 4, and θ 42 ≥arctan(1 / n).

[0054] By setting a dichroic film and a reflective film on the first prism 2 and adjusting the incident angle of the light to cause total internal reflection, the light emitted by the light source 1 is folded and propagated multiple times in a limited space, so as to reduce the size of the visual optical system, realize the miniaturization of the visual optical system, and improve its lightness to meet the requirements of wearability and better fit the user experience.

[0055] In order to facilitate the description of the visual optical system formed by the light source 1 and the first prism 2, as shown in FIG. Figure 7 As shown, a coordinate system is established on the visual optical system, with the center of the exit pupil 9 as the origin of the coordinate system, the direction parallel to the optical axis and toward the optical device as the Z axis, the direction perpendicular to the Z axis and vertically upward as the Y axis, and the direction perpendicular to the YOZ plane as the X axis.

[0056] The Z eccentricity range of the center of the first optical surface is 17 mm to 24 mm, the Y eccentricity range is -2 mm to +1 mm, and the inclination angle range around the XOY plane is -32° to -24°.

[0057] The Z eccentricity range of the center of the second optical surface 4 is 1 mm to 5 mm, and the tilt angle (Alpha angle) range around the XOY plane is ±5°. The second optical surface 4 is 13 mm to 20 mm away from the center of the exit pupil 9 along the Z axis.

[0058] The Z eccentricity range of the center of the third optical surface 5 is 16.6 mm to 23.6 mm, the Y eccentricity range is 9 mm to 17 mm, and the inclination angle range around the XOY plane is 46° to 56°.

[0059] The Z eccentricity range of the center of the light emitting surface of the light source 1 is 17 mm to 27 mm, the Y eccentricity range is -1 mm to +1 mm, and the inclination angle range around the XOY plane is 46° to 56°.

[0060] The visual optical system formed based on the above parameter data makes the diagonal field of view of the focal plane display light path of the system observed from the position of the exit pupil 9 not less than 35°; the field of view angle in the horizontal direction should be at least greater than 30°. The diameter of the exit pupil 9 of the system should be at least greater than 7mm; the focal plane depth range of the system is: 100mm~100000mm; the focal length range of the first prism 2 in the system is: 13mm~21mm.

[0061] A specific feasible implementation of this embodiment will be given below. This patent can be implemented in a variety of different forms and should not be construed as being limited to this implementation. Instead, these embodiments are provided to make the present disclosure sufficient and complete and to fully convey the concept of this patent to those skilled in the art.

[0062] like Figure 8 As shown, the visual optical system formed by this specific implementation is combined with the specific parameters of the visual optical system given in Table 1 to obtain a visual optical system with a field of view angle of 35°, an exit pupil 9 diameter of 7 mm, and a focal plane depth of 2000 mm, wherein the focal length of the first prism 2 is 17.1 mm.

[0063] Table 1 Visual optical system parameters

[0064]

[0065]

[0066] The surface 101 corresponds to the final imaging, 102 corresponds to the exit pupil, 103 corresponds to the second optical surface, 104 corresponds to the first optical surface, 105 corresponds to the third optical surface, 106 corresponds to the protective glass in front of the light source, and 107 corresponds to the light source exit surface.

[0067] The free-form surfaces mentioned in Table 1 satisfy the XY polynomial, which can be expressed as: c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, C i are the coefficients of the higher-order terms, and m and n are expressed as the power levels of the polynomial.

[0068] Table 2 shows the corresponding free-form surface coefficients of the free-form surface in this embodiment.

[0069] Table 2 Free surface coefficients

[0070]

[0071]

[0072] like Fig. 9As shown in the figure, the MTF of each sampling field obtained based on the above implementation is higher than 0.1 at 30lp / mm, indicating that the imaging quality of the system is excellent, wherein the horizontal axis represents the sampling frequency of the image space, the vertical axis represents the contrast, and F1 to F9 are the sampling fields used to evaluate the display quality of the system. Fig.10 As shown, the distortion-free situation under ideal conditions is compared with the actual state after being processed by the visual optical system, and it is found that the optical distortion is less than 8% and the imaging quality is good.

[0073] Furthermore, if Fig.11 As shown, in order to correct off-axis aberration, a second prism 6 is added between the light source 1 and the first prism 2.

[0074] The light emitted by the light source 1 first passes through the second prism 6 and then enters the first prism 2. The second prism 6 includes a first optically effective surface 7 and a second optically effective surface 8. The first optically effective surface 7 is arranged opposite to the light source 1, and the second optically effective surface 8 is arranged opposite to the first optically effective surface 7. The light emitted by the light source 1 passes through the first optically effective surface 7 and the second optically effective surface 8 in sequence.

[0075] Furthermore, when the light emitted by the light source 1 is incident on the second optically effective surface 8, its incident angle is less than arctan (1 / n), thereby avoiding total internal reflection of the light on the second optically effective surface 8. In addition, the length of the second optically effective surface 8 is less than the length of the first optical surface, and it is also required that the upper and lower boundaries of the light beam of the light source 1 emitted by the light source 1 can be incident on the second optically effective surface 8.

[0076] Furthermore, the second optically effective surface 8 and the first optical surface are arranged in a close connection, so as to support each other and produce a better imaging effect.

[0077] In order to facilitate the description of the visual optical system formed by the light source 1 and the first prism 2, as shown in FIG. Fig.12 As shown, a coordinate system is established on the visual optical system, with the center of the exit pupil 9 as the origin of the coordinate system, the direction parallel to the optical axis and toward the optical device as the Z axis, the direction perpendicular to the Z axis and vertically upward as the Y axis, and the direction perpendicular to the YOZ plane as the X axis. The parameters of each optical surface of the first prism 2 are consistent with the data in the previously established coordinate system, and will not be repeated here.

[0078] The Z eccentricity range of the center of the first optically effective surface 7 is 19 mm to 27 mm, the Y eccentricity range is -1 mm to +1 mm, and the inclination angle range around the XOY plane is 38° to 48°.

[0079] The parameters of the second optically effective surface 8 are consistent with those of the first optical surface.

[0080] The Z eccentricity range of the center of the light emitting surface of the light source 1 is 20 mm to 28 mm, the Y eccentricity range is -2 mm to +2 mm, and the inclination angle range around the XOY plane is 47° to 57°.

[0081] The visual optical system formed based on the above parameter data makes the diagonal field of view of the focal plane display light path of the system not less than 35° when observed from the position of the exit pupil 9; the field of view angle in the horizontal direction should be at least greater than 30°. The diameter of the exit pupil 9 of the system should be at least greater than 7mm; the focal plane depth range of the system is: 100mm~100000mm; the focal length range of the prism in the system is: 13mm~21mm.

[0082] A specific feasible implementation of this embodiment will be given below. This patent can be implemented in a variety of different forms and should not be construed as being limited to this implementation. Instead, these embodiments are provided to make the present disclosure sufficient and complete and to fully convey the concept of this patent to those skilled in the art.

[0083] like Fig.13 As shown, the visual optical system formed by this specific implementation is combined with the specific parameters of the visual optical system given in Table 3 to obtain a visual optical system with a field angle of 35°, an exit pupil 9 diameter of 7 mm, and a focal plane depth of 2000 mm, wherein the focal length of the prism is 17.2 mm.

[0084] Table 3 Visual optical system parameters

[0085]

[0086]

[0087] The above-mentioned surface 201 corresponds to the final imaging, 202 corresponds to the exit pupil, 203 corresponds to the second optical surface, 204 corresponds to the first optical surface, 205 corresponds to the third optical surface, 206 corresponds to the first optical effective surface, 207 is the protective glass in front of the light source, and 208 corresponds to the light source exit surface.

[0088] The free-form surfaces mentioned in Table 3 satisfy the XY polynomial, which can be expressed as: c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, C i is the coefficient of the high-order term, m and n are expressed as the power order of the polynomial. Table 4 shows the corresponding free-form surface coefficients of the free-form surface in this embodiment.

[0089] Table 4 Free surface coefficients

[0090]

[0091]

[0092] like Fig.14 As shown in the figure, the MTF of each sampling field obtained based on the above implementation is higher than 0.1 at 30lp / mm, indicating that the imaging quality of the system is excellent, wherein the horizontal axis represents the sampling frequency of the image space, the vertical axis represents the contrast, and F1 to F9 are the sampling fields used to evaluate the display quality of the system. Fig.15 As shown, the distortion-free situation under ideal conditions is compared with the actual state after being processed by the visual optical system, and it is found that the optical distortion is less than 8% and the imaging quality is good.

[0093] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A visual optical system, characterized in that: include: A first prism comprises a first optical surface, wherein a beam splitting film is disposed on the first optical surface; A second optical surface is arranged opposite to the first optical surface and is spaced apart from the first optical surface in a width direction; A third optical surface is arranged between the first optical surface and the second optical surface and is arranged opposite to the second optical surface, and a reflective film is arranged on the third optical surface; a light source, located outside the first prism, arranged opposite to the first optical surface and spaced apart in the width direction; An exit pupil, located on both sides of the light source in the width direction of the first prism; A visual optical path is formed between the light source, the first optical surface, the second optical surface and the third optical surface, wherein the light is emitted from the light source to the first optical surface, passes through the first optical surface under the action of the dichroic film, is incident on the second optical surface at a first incident angle and is reflected from the third optical surface, is incident on the second optical surface at a second incident angle under the action of the reflective film on the third optical surface, is reflected from the first optical surface, and then reaches and passes through the second optical surface under the reflection of the dichroic film on the first optical surface and is emitted toward the exit pupil, forming an image with a focal plane depth greater than 1m at the exit pupil position; wherein the first incident angle and the second incident angle are both greater than or equal to arctan(1 / n), wherein n is the refractive index of the first prism material when the wavelength of the light is 586nm.

2. The visual optical system according to claim 1, characterized in that: The splitting ratio of the splitter film is 1:

1.

3. The visual optical system according to claim 1, characterized in that: A coordinate system is established with the center of the exit pupil as the origin O of the coordinate system, the direction parallel to the optical axis and toward the first prism as the Z axis, the direction perpendicular to the Z axis and pointing upward as the Y axis, and the direction perpendicular to the YOZ plane as the X axis; the Z eccentricity range of the center of the first optical surface is 17 mm to 24 mm, the Y eccentricity range is -2 mm to +1 mm, and the inclination angle range around the XOY plane is -32° to -24°; The Z eccentricity range of the center of the second optical surface is 1 mm to 5 mm, and the inclination angle range around the XOY plane is ±5°; the second optical surface is 13 mm to 20 mm away from the center of the exit pupil along the Z axis; The Z eccentricity range of the center of the third optical surface is 16.6 mm to 23.6 mm, the Y eccentricity range is 9 mm to 17 mm, and the inclination angle range about the XOY plane is 46° to 56°; The Z eccentricity range of the light emitting surface center of the light source is 17mm to 27mm, the Y eccentricity range is -1mm to +1mm, and the inclination angle range around the XOY plane is 46° to 56°; The diagonal field of view of the focal plane display light path of the formed visual optical system is not less than 35°; the field angle in the horizontal direction should be at least greater than 30°; the exit pupil diameter of the system is at least greater than 7mm; the focal plane depth range of the system is: 100mm~100000mm; the focal length range of the first prism in the system is: 13mm~21mm.

4. The visual optical system according to claim 1, characterized in that: The first optical surface at least partially covers the plane where the light source is located in a direction perpendicular to the width.

5. The visual optical system according to claim 1, characterized in that: The first prism is in a triangular prism-like shape.

6. The visual optical system according to claim 1, characterized in that: The visual optical system further includes a second prism, wherein the second prism is disposed between the light source and the first prism; The second prism includes a first optically effective surface and a second optically effective surface, the first optically effective surface is arranged opposite to the light source, and the second optically effective surface is arranged opposite to the first prism, and the light emitted by the light source passes through the first optically effective surface and the second optically effective surface in sequence and is incident on the first prism.

7. The visual optical system according to claim 6, characterized in that: A coordinate system is established by taking the center of the exit pupil as the origin of the coordinate system, taking the direction parallel to the optical axis and toward the first prism as the Z axis, taking the direction perpendicular to the Z axis and pointing upward as the Y axis, and taking the direction perpendicular to the YOZ plane as the X axis; The Z eccentricity range of the center of the first optical effective surface is 19 mm to 27 mm, the Y eccentricity range is -1 mm to +1 mm, and the inclination angle range around the XOY plane is 38° to 48°; The Z eccentricity range of the center of the light emitting surface of the light source is 20 mm to 28 mm, the Y eccentricity range is -2 mm to +2 mm, and the inclination angle range around the XOY plane is 47° to 57°.

8. The visual optical system according to claim 7, characterized in that: The second optically effective surface is disposed in contact with the first optical surface.

9. The visual optical system according to claim 8, characterized in that: The first optical surface and the first optically effective surface satisfy an XY polynomial, which is expressed as: c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, C i are the coefficients of the higher-order terms, m and n are expressed as the power levels of the polynomials, The first optical surface has a radius of curvature of -137.8, a refractive index of 1.53, an Abbe number of 55.9, a Y eccentricity of 0.15 mm, a Z eccentricity of 20.67 mm, and an inclination angle about the XOY plane of -25.39°; The radius of curvature of the second optically effective surface is -89.1, the Y eccentricity is -0.13 mm, the Z eccentricity is 22.19 mm, and the inclination angle around the XOY plane is -42.83°.

10. The visual optical system according to claim 7, characterized in that: When the light emitted by the light source is incident on the second optically effective surface, the corresponding incident angle is less than arctan (1 / n).

Images