Eyepiece optical system

Abstract

The present invention discloses an eyepiece optical system, which is used to allow imaging light to enter the observer's eyes from a display screen through the eyepiece optical system to form an image. The direction toward the eye is the eye side. The direction toward the display screen is the display side. The eyepiece optical system includes a first lens and a second lens in sequence along an optical axis from the eye side to the display side. Each lens has an eye side and a display side. The first lens has a positive refractive power. The second lens has a positive refractive power. The circumferential area of ​​the eye side of the second lens is a plane. The lenses of the eyepiece optical system only have the above two lenses, and meet the following conditional formula: 0.400≦T1 / T2≦2.000. The eyepiece optical system of the present invention is thin and light, has a large half-eye viewing angle and good imaging quality.

Description

[0001] This invention patent application is a divisional application. The application number of the original application is 201811101697.6, the application date is September 20, 2018, and the invention name is: Eyepiece optical system. Technical Field

[0002] The invention relates to the field of optical systems, and in particular to an eyepiece optical system. Background Art

[0003] Virtual reality (VR) is a three-dimensional virtual world that uses computer technology to simulate and generate a virtual world. It provides users with visual, auditory and other sensory simulations, allowing users to feel as if they are in the real world. Currently, existing VR devices are mainly based on visual experience. The parallax of the human eye is simulated by splitting the screen with slightly different perspectives corresponding to the left and right eyes to achieve stereoscopic vision. In order to reduce the size of the virtual reality device and allow users to get a magnified visual experience through a smaller display screen, the eyepiece optical system with a magnifying function has become one of the themes of VR research and development.

[0004] The existing eyepiece optical system faces the following problems: the half-eye viewing angle is small, which makes the observer feel that there is a black screen around the screen, so the user's immersion in the virtual world needs to be improved. In addition, if the half-eye viewing angle is increased, the volume and weight of the lens and the display screen will double. Therefore, how to increase the half-eye viewing angle and reduce the volume and weight of the system is a problem that needs to be improved in the eyepiece optical system. Summary of the invention

[0005] The invention provides an eyepiece optical system, which is light and thin, has a large half-eye viewing angle and good imaging quality.

[0006] One embodiment of the present invention provides an eyepiece optical system for allowing imaging light to enter the observer's eyes from a display screen through the eyepiece optical system to form an image. The direction toward the eye is the eye side. The direction toward the display screen is the display side, and the first lens and the second lens are included in sequence along the optical axis from the eye side to the display side. The first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through. The first lens has a positive refractive power. The second lens has a positive refractive power and the circumferential area of ​​the eye side surface of the second lens is a plane. The lenses of the eyepiece optical system are only the above two lenses. The eyepiece optical system meets the following conditions: 0.400≦T1 / T2≦2.000.

[0007] One embodiment of the present invention provides an eyepiece optical system for allowing imaging light to enter the observer's eyes from a display screen through the eyepiece optical system to form an image. The direction toward the eye is the eye side. The direction toward the display screen is the display side, and the first lens and the second lens are included in sequence along the optical axis from the eye side to the display side. The first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through. The first lens has a positive refractive power, and the optical axis area of ​​the eye side surface of the first lens is a plane. The second lens has a positive refractive power, and the optical axis area of ​​the eye side surface of the second lens is a plane. The lenses of the eyepiece optical system are only the above-mentioned two lenses. The eyepiece optical system meets the following conditional formula: 0.400≦T1 / T2≦2.000.

[0008] One embodiment of the present invention provides an eyepiece optical system for allowing imaging light to enter the observer's eyes from a display screen through the eyepiece optical system to form an image. The direction toward the eye is the eye side. The direction toward the display screen is the display side, and the first lens and the second lens are included in sequence along the optical axis from the eye side to the display side. The first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through. The first lens has a positive refractive power and the circumferential area of ​​the eye side surface of the first lens is a plane. The second lens has a positive refractive power and the optical axis area of ​​the eye side surface of the second lens is a plane. The lenses of the eyepiece optical system are only the above-mentioned two lenses. The eyepiece optical system meets the following conditional formula: 0.400≦T1 / T2≦2.000.

[0009] One embodiment of the present invention provides an eyepiece optical system for allowing imaging light to enter the observer's eyes from a display screen through the eyepiece optical system to form an image. The direction toward the eye is the eye side. The direction toward the display screen is the display side, and the first lens and the second lens are included in sequence along the optical axis from the eye side to the display side. The first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through. The first lens has a positive refractive power. One of the optical axis area of ​​the eye side surface of the first lens and the optical axis area of ​​the display side surface of the first lens is a plane. The second lens has a positive refractive power and the optical axis area of ​​the eye side surface of the second lens is a plane. The only lenses of the eyepiece optical system that meet the following conditional formula are the above-mentioned two lenses: 0.400≦T1 / T2≦2.000.

[0010] One embodiment of the present invention provides an eyepiece optical system for allowing imaging light to enter the observer's eyes from a display screen through the eyepiece optical system to form an image. The direction toward the eye is the eye side. The direction toward the display screen is the display side, and the first lens and the second lens are included in sequence along the optical axis from the eye side to the display side. The first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through. The first lens has a positive refractive power. The second lens has a positive refractive power and the optical axis area of ​​the eye side surface of the second lens is a plane. The lenses of the eyepiece optical system are only the above two lenses. The eyepiece optical system meets the following conditional formulas: 0.400≦T1 / T2≦2.000, and 6.000≦EFL / T1.

[0011] Furthermore, the eyepiece optical system further meets the following conditional formula: 6.000≦EFL / T 1.

[0012] Furthermore, the eyepiece optical system further meets the following conditional formula: 6.000≦EFL / T2.

[0013] Furthermore, the eyepiece optical system further meets the following conditional formula: 4.300≦EFL / TL.

[0014] Furthermore, the eyepiece optical system further meets the following conditional formula: 4.490≦EFL / ALT.

[0015] Furthermore, the eyepiece optical system further meets the following conditional expression: 6.500° / mm≦ω / TL≦30.000° / mm.

[0016] Furthermore, the eyepiece optical system further meets the following conditional formula: 1.500≦T1 / G12≦19.000.

[0017] Furthermore, the eyepiece optical system further meets the following conditional formula: 4.630≦TTL / ALT.

[0018] Furthermore, the eyepiece optical system further meets the following conditional formula: 1.800≦T2 / G12≦19.000.

[0019] Furthermore, the eyepiece optical system further meets the following conditional formula: 4.340≦TTL / TL.

[0020] Furthermore, the eyepiece optical system further meets the following conditional formula: 5.500≦G2D / T 1.

[0021] Furthermore, the eyepiece optical system further meets the following conditional formula: 5.500≦G2D / T2.

[0022] Furthermore, the display side surface of the first lens is a Fresnel surface.

[0023] Furthermore, the eyepiece optical system further meets the following conditional expression: 0.970≦D1 / D2≦1.500.

[0024] Furthermore, the eyepiece optical system further meets the following conditional formula: 3.750≦D4 / TL.

[0025] Furthermore, the eyepiece optical system further meets the following conditional expression: 4.000≦D4 / ALTL.

[0026] Wherein, D1 is the longest distance of the eye side of the first lens through the center of the Fresnel surface, D2 is the longest side of the display screen, and D4 is the longest distance of the display side of the first lens from the center of the Fresnel surface to the circumference of the first lens; ALT is the sum of the thicknesses of the first lens and the second lens on the optical axis; T1 is the thickness of the first lens on the optical axis, and T2 is the thickness of the second lens on the optical axis. G12 is the air gap from the first lens to the second lens on the optical axis, and TTL is the distance from the eye side of the first lens to the display screen on the optical axis. EFL is the system focal length of the eyepiece optical system. G2D is the distance from the second lens to the display screen on the optical axis. TL is the distance from the eye side of the first lens to the display side of the second lens on the optical axis. ω is the half-eye viewing angle of the eyepiece optical system.

[0027] Based on the above, in the eyepiece optical system of the embodiment of the present invention, by designing the surface shapes of the first lens and the second lens and combining at least one of the following two conditional expressions: (1). 0.400≦T1 / T2≦2.000 or (2). 6.000≦EFL / T1, the half-eye viewing angle of the system can be increased without increasing the volume and weight of the system while maintaining the size of the display screen and having good imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram illustrating an eyepiece optical system.

[0029] Figure 2 It is a schematic diagram illustrating the surface structure of a lens.

[0030] Figure 3 It is a schematic diagram illustrating the concave-convex structure of a lens surface and the focus of light.

[0031] Figure 4 is a schematic diagram illustrating the surface structure of a lens of Example 1.

[0032] Figure 5 is a schematic diagram illustrating the surface structure of a lens of Example 2.

[0033] Figure 6 is a schematic diagram illustrating the surface structure of a lens of Example 3.

[0034] Figure 7 A is a schematic diagram illustrating a lens cutting shape and a lens parameter diagram according to an embodiment of the present invention.

[0035] Figure 7 B is a schematic diagram illustrating a display screen cut shape and a display screen parameter diagram according to an embodiment of the present invention.

[0036] Figure 8 FIG. 4 is a schematic diagram illustrating a Fresnel surface according to an embodiment of the present invention.

[0037] Fig. 9 It is a schematic diagram of the eyepiece optical system of the first embodiment of the present invention.

[0038] Fig.10 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the first embodiment.

[0039] Fig.11 A table diagram showing detailed optical data of the eyepiece optical system of the first embodiment of the present invention.

[0040] Fig.12 A table showing aspheric parameters of the eyepiece optical system of the first embodiment of the present invention.

[0041] Fig.13 FIG. 4 is a schematic diagram of an eyepiece optical system according to a second embodiment of the present invention.

[0042] Fig.14 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the second embodiment.

[0043] Fig.15 A table diagram showing detailed optical data of the eyepiece optical system of the second embodiment of the present invention.

[0044] Fig.16 A table showing aspheric parameters of the eyepiece optical system of the second embodiment of the present invention.

[0045] Fig.17 FIG. 4 is a schematic diagram of an eyepiece optical system according to a third embodiment of the present invention.

[0046] Fig.18 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the third embodiment.

[0047] Fig.19 A table diagram showing detailed optical data of the eyepiece optical system of the third embodiment of the present invention.

[0048] Fig. 20A table showing aspheric parameters of the eyepiece optical system of the third embodiment of the present invention.

[0049] Fig.21 FIG. 4 is a schematic diagram of an eyepiece optical system according to a fourth embodiment of the present invention.

[0050] Fig. 22 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the fourth embodiment.

[0051] Fig.23 A table diagram showing detailed optical data of the eyepiece optical system of the fourth embodiment of the present invention.

[0052] Fig.24 A table showing aspheric parameters of the eyepiece optical system of the fourth embodiment of the present invention.

[0053] Fig.25 FIG. 4 is a schematic diagram of an eyepiece optical system according to a fifth embodiment of the present invention.

[0054] Fig.26 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the fifth embodiment.

[0055] Fig. 27 A table diagram showing detailed optical data of the eyepiece optical system of the fifth embodiment of the present invention.

[0056] Fig.28 A table showing aspheric parameters of the eyepiece optical system of the fifth embodiment of the present invention.

[0057] Fig.29 FIG. 4 is a schematic diagram of an eyepiece optical system according to a sixth embodiment of the present invention.

[0058] Fig.30 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the sixth embodiment.

[0059] Fig.31 A table diagram showing detailed optical data of the eyepiece optical system of the sixth embodiment of the present invention.

[0060] Fig.32 A table showing aspheric parameters of the eyepiece optical system of the sixth embodiment of the present invention.

[0061] Fig.33 FIG. 4 is a schematic diagram of an eyepiece optical system according to a seventh embodiment of the present invention.

[0062] Fig.34 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the seventh embodiment.

[0063] Fig.35 A table diagram showing detailed optical data of the eyepiece optical system of the seventh embodiment of the present invention.

[0064] Fig.36 A table showing aspheric parameters of the eyepiece optical system of the seventh embodiment of the present invention.

[0065] Fig.37 FIG. 4 is a schematic diagram of an eyepiece optical system according to an eighth embodiment of the present invention.

[0066] Fig.38 Graphs showing the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the eighth embodiment.

[0067] Fig.39 A table diagram showing detailed optical data of the eyepiece optical system of the eighth embodiment of the present invention.

[0068] Fig.40 A table showing aspheric parameters of the eyepiece optical system of the eighth embodiment of the present invention.

[0069] Fig.41 A numerical table diagram showing important parameters of the eyepiece optical system and their relationship expressions of the first to eighth embodiments of the present invention. DETAILED DESCRIPTION

[0070] Before describing the present invention in detail, the following are some of the symbols in the accompanying drawings:

[0071] 0: pupil; 1: first lens; 10, V100: eyepiece optical system; 100, 200, 300, 400, 500: lens; 130: assembly; 15, 25, 110, 410, 510: eye side; 16, 26, 120, 320: display side; 2: second lens; 211, 212: parallel light; AA: display area; F: Fresnel surface; FC: center of Fresnel surface; 99, V50: display screen; A1: eye side; A2: display side; CP: center point; CF: circumference; CP1: first center point; CP2: second center point; D: display; D1, D3, D4: lens parameters; D2: display screen parameters; EL : extension line; I: optical axis; ICD: displayed image circle; Lm: marginal ray; Lc: principal ray; OB: optical boundary; M, R: intersection points; PC: central convex surface; PD: pupil distance; P1: effective sub-surface; P2: invalid sub-surface; TP1: first transition point; TP2: second transition point; V60: eye; VD: virtual image distance; VI: imaging ray; VV: magnified virtual image; Z1, 15p1, 151, 152, 161, 25p1, 251, 252, 261, 26p1: optical axis area; Z2, 15p3, 153, 154, 163, 25p3, 253, 254, 263: circular area; ω: half-eye viewing angle; Z3: relay area.

[0072] Generally speaking, the light direction of the eyepiece optical system V100 is that an imaging light VI is emitted from the display screen V50, enters the eye V60 through the eyepiece optical system V100, focuses on the retina of the eye V60, and generates an enlarged virtual image VV at the virtual image distance VD, such as Figure 1 The optical specifications of the present invention are described below based on the assumption that the direction of the light is reversely tracked as a parallel imaging light beam from the eye side through the eyepiece optical system to the display screen to form a focused image.

[0073] The optical system of this specification includes at least one lens, which receives the imaging light from the incident optical system that is parallel to the optical axis and within an angle of half the eye viewing angle (ω) relative to the optical axis. The imaging light forms an image on the display screen through the optical system. The "lens has a positive refractive power (or negative refractive power)" refers to the paraxial refractive power of the lens calculated by Gaussian optical theory is positive (or negative). The "eye side (or display side) of the lens" is defined as a specific range where the imaging light passes through the lens surface. The imaging light includes at least two types of light: the chief ray Lc and the marginal ray Lm (such as Figure 2 The eye side (or display side) of the lens can be divided into different areas according to different positions, including an optical axis area, a circumferential area, or one or more relay areas in some embodiments. The description of these areas will be described in detail below.

[0074] Figure 2 is a radial cross-sectional view of the lens 100. Two reference points on the surface of the lens 100 are defined: a center point and a transition point. The center point of the lens surface is an intersection of the surface and the optical axis I. Figure 2 As shown in the example, the first center point CP1 is located on the eye side 110 of the lens 100, and the second center point CP2 is located on the display side 120 of the lens 100. A transition point is a point on the lens surface, and the tangent of the point is perpendicular to the optical axis I. The optical boundary OB of the lens surface is defined as the point where the radially outermost edge ray Lm passing through the lens surface intersects the lens surface. All transition points are located between the optical axis I and the optical boundary OB of the lens surface. In addition, if a single lens surface has multiple transition points, the transition points are named in sequence from the first transition point in the radial outward direction. For example, the first transition point TP1 (closest to the optical axis I), the second transition point TP2 (closest to the optical axis I), and the second transition point TP2 (closest to the optical axis I). Figure 5 as shown) and the Nth conversion point (farthest from the optical axis I).

[0075] The range from the center point to the first transition point TP1 is defined as the optical axis area, wherein the optical axis area includes the center point. The area from the Nth transition point farthest from the optical axis I to the optical boundary OB is defined as the circumferential area. In some embodiments, a relay area between the optical axis area and the circumferential area may be further included, and the number of relay areas depends on the number of transition points.

[0076] When a light ray parallel to the optical axis I passes through an area, if the light ray is deflected toward the optical axis I and the intersection with the optical axis I is located at the display side A2 of the lens, then the area is convex. When a light ray parallel to the optical axis I passes through an area, if the intersection of the extended line of the light ray and the optical axis I is located at the eye side A1 of the lens, then the area is concave.

[0077] In addition, see Figure 2 The lens 100 may further include an assembly portion 130 extending radially outward from the optical boundary OB. The assembly portion 130 is generally used for assembling the lens 100 to a corresponding element (not shown) of the optical system. The imaging light does not reach the assembly portion 130. The structure and shape of the assembly portion 130 are merely examples for illustrating the present invention and are not intended to limit the scope of the present invention. The assembly portion 130 of the lens discussed below may be partially or completely omitted in the drawings.

[0078] See also Figure 3 , define the area between the center point CP and the first transition point TP1 as the optical axis area Z1. Define the area between the first transition point TP1 and the optical boundary OB of the lens surface as the circumferential area Z2. Figure 3 As shown, after passing through the optical axis area Z1, the parallel light 211 intersects with the optical axis I at the display side A2 of the lens 200, that is, the focus of the parallel light 211 passing through the optical axis area Z1 is located at point R on the display side A2 of the lens 200. Since the light intersects with the optical axis I at the display side A2 of the lens 200, the optical axis area Z1 is a convex surface. On the contrary, the parallel light 212 diverges after passing through the circumferential area Z2. Figure 3 As shown, the extended line EL of the parallel light 212 after passing through the circumferential area Z2 intersects with the optical axis I at the eye side A1 of the lens 200, that is, the focus of the parallel light 212 passing through the circumferential area Z2 is located at the point M on the eye side A1 of the lens 200. Since the extended line EL of the light intersects with the optical axis I at the eye side A1 of the lens 200, the circumferential area Z2 is a concave surface. Figure 3 In the lens 200 shown, the first transition point TP1 is the boundary between the optical axis area and the circumferential area, that is, the first transition point TP1 is the boundary point where the convex surface turns into the concave surface.

[0079] On the other hand, the surface convexity of the optical axis area can also be determined according to the judgment method of the general knowledgeable person in the field, that is, the convexity of the surface shape of the optical axis area of ​​the lens can be determined by the positive and negative signs of the curvature radius of the paraxial axis (abbreviated as R value). R value can be commonly used in optical design software, such as Zemax or CodeV. R value is also commonly found in the lens data sheet of optical design software. For the eye side, when the R value is positive, the optical axis area of ​​the eye side is determined to be convex; when the R value is negative, the optical axis area of ​​the eye side is determined to be concave. On the contrary, for the display side, when the R value is positive, the optical axis area of ​​the display side is determined to be concave; when the R value is negative, the optical axis area of ​​the display side is determined to be convex. The result of this method is consistent with the result of the above-mentioned determination method by the intersection of the light / light extension line and the optical axis. The determination method of the intersection of the light / light extension line and the optical axis is to determine the surface convexity by locating the focus of a light parallel to the optical axis on the eye side or the display side of the lens. The terms “a region is convex (or concave)”, “a region is convex (or concave)” or “a convex (or concave) region” described in this specification can be used interchangeably.

[0080] Figures 4 to 6 Examples are provided for determining the surface shape and area boundaries of lens areas in various situations, including the aforementioned optical axis area, circumferential area, and relay area.

[0081] Figure 4 is a radial cross-sectional view of the lens 300. Figure 4 , the display side surface 320 of the lens 300 has only one transition point TP1 within the optical boundary OB. The optical axis area Z1 and the circumferential area Z2 of the display side surface 320 of the lens 300 are as follows: Figure 4 The R value of the display side surface 320 is positive (ie, R>0), and therefore, the optical axis region Z1 is a concave surface.

[0082] Generally speaking, the shapes of the areas bounded by the conversion point are opposite to those of the adjacent areas. Therefore, the conversion point can be used to define the transition of the surface shape, that is, from concave to convex or from convex to concave. Figure 4 In the figure, since the optical axis area Z1 is a concave surface, the surface shape changes at the transition point TP1, so the circumferential area Z2 is a convex surface.

[0083] Figure 5 is a radial cross-sectional view of the lens 400. Figure 5 , there is a first transition point TP1 and a second transition point TP2 on the eye side surface 410 of the lens 400. The area between the optical axis I and the first transition point TP1 is defined as an optical axis region Z1 of the eye side surface 410. The R value of the eye side surface 410 is positive (ie, R>0), and therefore, the optical axis region Z1 is a convex surface.

[0084] The area between the second transition point TP2 and the optical boundary OB of the eye side surface 410 of the lens 400 is defined as a circumferential area Z2, and the circumferential area Z2 of the eye side surface 410 is also a convex surface. In addition, the area between the first transition point TP1 and the second transition point TP2 is defined as a relay area Z3, and the relay area Z3 of the eye side surface 410 is a concave surface. Figure 5 The eye-side surface 410 includes, radially outward from the optical axis I, an optical axis region Z1 between the optical axis I and the first conversion point TP1, a relay region Z3 between the first conversion point TP1 and the second conversion point TP2, and a circumferential region Z2 between the second conversion point TP2 and the optical boundary OB of the eye-side surface 410 of the lens 400. Since the optical axis region Z1 is a convex surface, the surface shape changes from the first conversion point TP1 to a concave surface, so the relay region Z3 is a concave surface, and the surface shape changes from the second conversion point TP2 to a convex surface, so the circumferential region Z2 is a convex surface.

[0085] Figure 6 is a radial cross-sectional view of the lens 500. The eye side surface 510 of the lens 500 has no transition point. For a lens surface without a transition point, such as the eye side surface 510 of the lens 500, 0 to 50% of the distance from the optical axis I to the optical boundary OB of the lens surface is defined as the optical axis area, and 50 to 100% of the distance from the optical axis I to the optical boundary OB of the lens surface is defined as the circumferential area. Figure 6 The lens 500 shown in the figure defines the optical axis region Z1 of the eye side surface 510 as 50% of the distance from the optical axis I to the optical boundary OB of the lens 500 surface. The R value of the eye side surface 510 is positive (i.e., R>0), so the optical axis region Z1 is a convex surface. Since the eye side surface 510 of the lens 500 has no transition point, the circumferential region Z2 of the eye side surface 510 is also a convex surface. The lens 500 may further have an assembly portion (not shown) extending radially outward from the circumferential region Z2.

[0086] Figure 7 Schematic diagram of lens cutting shape and lens parameters according to an embodiment of the present invention. Figure 8 This is a schematic diagram of the display screen cutting shape and display screen parameters according to an embodiment of the present invention. Figure 7 and Figure 8 Since the eyepiece optical system of the embodiment of the present invention has a design of a large half-eye viewing angle, the lens and the display screen cannot cover the display image circle ICD (image circle diameter, ICD) corresponding to the maximum viewing angle of a single eye due to the factor of the pupil distance PD (Pupil Distance, PD). Therefore, the shape of the lens of the embodiment of the present invention needs to be cut and the shape of the display screen is also changed, as shown in FIG. Figure 7 and Figure 8As shown, the effective display image is the overlapped portion of the display image circles ICD of both eyes and the display area AA of the display D (ie, the area indicated by the diagonal lines). The lens parameters and the display image parameters will be defined in detail in the following paragraphs.

[0087] From a macroscopic perspective, the details of the Fresnel surface shape of the lens of the embodiment of the present invention are relatively small and it is difficult to see the specific morphology. For a detailed description of the Fresnel surface of the embodiment of the present invention, please refer to Figure 8 , Figure 8 is a schematic diagram of an enlarged Fresnel surface, for example, a schematic diagram of a convex Fresnel surface. In an embodiment of the present invention, the Fresnel surface F (Fresnel surface) represents the surface of a Fresnel lens. The Fresnel surface F has a plurality of concentric annular teeth surrounding the center FC of the Fresnel surface, which surround a central convex surface PC. Each annular tooth has an effective sub-surface P1 capable of refracting incident light to a predetermined direction and an invalid sub-surface P2 connecting two adjacent effective sub-surfaces P1. These effective sub-surfaces P1 and the central convex surface PC refract the incident light to a predetermined direction.

[0088] Fig. 9 is a schematic diagram of the eyepiece optical system of the first embodiment of the present invention, and Fig.10 A to Fig.10 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the first embodiment. Please refer to Fig. 9 The eyepiece optical system 10 of the first embodiment of the present invention is used to allow the imaging light of the display screen 99 to enter the observer's eyes through the eyepiece optical system 10 and the pupil 0 of the observer's eye to form an image. The display screen 99 is a vertical optical axis, which is convenient for correcting various aberrations of the imaging light and avoiding the poor aberration of a side with an inclined angle to the optical axis when the angle with the optical axis I is not equal to 90 degrees. The eye side A1 is the side facing the direction of the observer's eyes, and the display side A2 is the side facing the direction of the display screen 99. In this embodiment, the eyepiece optical system 10 includes a first lens 1 and a second lens 2 in sequence along an optical axis I from the eye side A1 to the display side A2. When the imaging light of the display screen 99 is emitted, it will pass through the second lens 2 and the first lens 1 in sequence, and then enter the observer's eyes through the pupil 0 of the observer. Then, the imaging light will form an image on the retina of the observer's eye.

[0089] Specifically, each of the first lens 1 to the second lens 2 of the eyepiece optical system 10 has an eye-side surface 15 and 25 facing the eye side A1 and allowing imaging light to pass therethrough, and a display-side surface 16 and 26 facing the display side A2 and allowing imaging light to pass therethrough.

[0090] In addition, in order to meet the requirement of product lightweighting, the first lens 1 and the second lens 2 both have refractive power and are made of plastic material, but the material of the first lens 1 and the second lens 2 is not limited thereto. In this embodiment, the only lenses with refractive power in the eyepiece optical system 10 are the first lens 1 and the second lens 2.

[0091] The first lens 1 has a positive refractive power. The optical axis region 15p1 of the eye side surface 15 of the first lens 1 is a plane, and the circumferential region 15p3 thereof is a plane. The optical axis region 161 of the display side surface 16 of the first lens 1 is a convex surface, and the circumferential region 163 thereof is a convex surface. The display side surface 16 of the first lens 1 is a Fresnel surface F

[0092] The second lens 2 has a positive refractive power. The optical axis area 25p1 of the eye side surface 25 of the second lens 2 is a plane, and the circumferential area 25p3 thereof is a plane. The optical axis area 261 of the display side surface 26 of the second lens 2 is a convex surface, and the circumferential area 263 thereof is a convex surface. The display side surface 26 of the second lens 2 is a Fresnel surface F.

[0093] Other detailed optical data of the first embodiment are as follows Fig.11 As shown. The overall system focal length (effective focal length, EFL) of the eyepiece optical system 10 of the first embodiment is 29.969 millimeters (mm), the half apparent field of view (half apparent field of view, ω) is 65.000°, and the aperture value (f-number, Fno) is 7.492. Specifically, the "aperture value" in this specification is the aperture value calculated based on the principle of reversibility of light, considering the pupil 0 of the observer as the incident pupil. In addition, the image height of the eyepiece optical system 10 of the first embodiment is 29.157 mm, and the system length (system length, SL) of the eyepiece optical system 10 of the first embodiment is 44.890 mm, where SL is the distance from the pupil 0 of the observer to the display screen 99 on the optical axis I. In addition, Fig.11 The effective radius here refers to half of the optical effective diameter (clear aperture).

[0094] In the first embodiment, the display side surfaces 16 and 26 of the first lens 1 and the second lens 2 are both aspherical surfaces, and the display side surfaces 16 and 26 of the first lens 1 and the second lens 2 are Fresnel surfaces F, wherein the effective sub-surface of each tooth of the Fresnel surface F is an aspherical surface, and the following aspherical coefficients of the display side surfaces are used to represent the effective sub-surfaces of these teeth, and these aspherical surfaces are defined according to the following formulas and are represented by the following curve equation (1):

[0095]

[0096] Y: the distance between the point on the aspheric curve and the optical axis;

[0097] Z: Depth of aspheric surface (the vertical distance between the point on the aspheric surface that is Y away from the optical axis and the tangent plane that is tangent to the vertex on the optical axis of the aspheric surface);

[0098] R: radius of curvature of the lens surface;

[0099] K: cone coefficient;

[0100] a i : i-th order aspheric coefficient.

[0101] The aspheric coefficients of the sides 16 and 26 in formula (1) are as follows: Fig.12 As shown. Among them, Fig.12 The number 16 in the middle column indicates the aspheric coefficient of the display side surface 16 of the first lens 1 , and the same applies to other columns.

[0102] In addition, the relationship between the important parameters and the conditional expressions in the eyepiece optical system 10 of the first embodiment is as follows: Fig.41 shown.

[0103] EPD (Exit pupil diameter) is the exit pupil diameter of the eyepiece optical system 10, corresponding to the diameter of the observer's pupil 0;

[0104] ER (Eye relief) is the exit pupil distance, which is the distance from the observer's pupil 0 to the first lens 1 on the optical axis I;

[0105] ω is the half apparent field of view, which is the half visual angle of the observer. Figure 1 drawn;

[0106] T1 is the thickness of the first lens 1 on the optical axis I;

[0107] T2 is the thickness of the second lens 1 on the optical axis I;

[0108] G12 is the air gap between the first lens 1 and the second lens 2 on the optical axis I;

[0109] G2D is the distance from the second lens 2 to the display screen 99 on the optical axis I;

[0110] D1 is the longest distance from the display side surface 16 of the first lens 1 through the center FC of the Fresnel surface F, as shown in Figure 7 As shown, the center FC refers to the optical center of the Fresnel surface F, that is, the center surrounded by the annular teeth of the Fresnel surface F;

[0111] D2 is the longest side of the display screen 99, that is, the long side of the display area AA of the display D. Figure 8 drawn;

[0112] D3 is the width of the display side surface 16 of the first lens 1 passing through the center FC of the Fresnel surface F and parallel to the longest side of the display screen 99, as shown in FIG. Figure 7 drawn;

[0113] D4 is the longest distance from the center FC of the Fresnel surface F of the display side surface 16 of the first lens 1 to the circumference CF of the first lens 1, as shown in FIG. Figure 7 drawn;

[0114] ImgH is the image height of the eyepiece optical system 10;

[0115] ALT is the sum of the thicknesses of the first lens 1 and the second lens 2 on the optical axis I, that is, the sum of T1 and T2;

[0116] TL is the distance between the eye side surface 15 of the first lens 1 and the display side surface 26 of the second lens 2 on the optical axis I;

[0117] TTL is the distance from the eye side surface 15 of the first lens 1 to the display screen 99 on the optical axis I;

[0118] SL is the system length, the distance from the observer pupil 0 to the display screen 99 on the optical axis I;

[0119] EFL is the system focal length of the eyepiece optical system 10 .

[0120] In addition, define:

[0121] f1 is the focal length of the first lens 1;

[0122] f2 is the focal length of the second lens 2;

[0123] n1 is the refractive index of the first lens 1;

[0124] n2 is the refractive index of the second lens 2;

[0125] V1 is the Abbe number of the first lens 1;

[0126] V2 is the Abbe number of the second lens 2 .

[0127] Also refer to Fig.10 A to Fig.10 D, Fig.10 A to Fig.10D is the various aberration diagrams of the eyepiece optical system of the first embodiment, and is the various aberration diagrams obtained by assuming that the direction of the light is reversely traced as a parallel imaging light from the eye side A1 through the pupil 0 and the eyepiece optical system 10 to the display screen 99 to focus the image. In this embodiment, the various aberration performances presented in the above various aberration diagrams will determine the various aberration performances of the imaging light from the display screen 99 on the retina of the observer's eyes. In other words, when the various aberrations presented in the above various aberration diagrams are smaller, the various aberration performances of the imaging of the retina of the observer's eyes will also be smaller, so that the observer can view an image with better imaging quality.

[0128] Specifically, Fig.10 The diagram of A illustrates the longitudinal spherical aberration of the first embodiment. Fig.10 B and Fig.10 The diagrams of FIG. 1 and FIG. 2 respectively illustrate the field curvature aberration in the sagittal direction and the field curvature aberration in the tangential direction of the first embodiment. Fig.10 The diagram of D illustrates the distortion aberration of the first embodiment. Fig.10 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.10 In A, the curves formed by each wavelength are very close and close to the middle, indicating that the off-axis light rays of different heights of each wavelength are concentrated near the imaging point. From the deflection amplitude of the curve of each wavelength, it can be seen that the imaging point deviation of the off-axis light rays of different heights is controlled within the range of ±0.49mm. Therefore, this embodiment does significantly improve the spherical aberration of the same wavelength. In addition, the distances between the three representative wavelengths of 486 nanometers, 588 nanometers and 656 nanometers are also very close to each other, indicating that the imaging positions of the light rays of different wavelengths are already very concentrated, thereby significantly improving the chromatic aberration.

[0129] exist Fig.10 B and Fig.10 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±3.00 mm, indicating that the eyepiece optical system 10 of the first embodiment can effectively eliminate aberrations. Fig.10The distortion aberration diagram of D shows that the distortion aberration of the first embodiment is maintained within the range of ±60%, indicating that the distortion aberration of the first embodiment meets the imaging quality requirements of the optical system. Based on this, it is shown that the first embodiment can still provide better imaging quality when the SL is shortened to about 44.890 mm compared to the existing eyepiece optical system. Therefore, the first embodiment can shorten the eyepiece optical system while maintaining good optical performance to achieve a thin product design. In addition, the eyepiece optical system 10 of the first embodiment has a larger eye viewing angle and can correct aberrations to maintain good imaging quality.

[0130] Fig.13 is a schematic diagram of an eyepiece optical system of a second embodiment of the present invention, and Fig.14 A to Fig.14 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the second embodiment. Please refer to Fig.13 , a second embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the differences between the two are as follows. The second embodiment and the first embodiment are more or less different in various optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2. It should be noted here that in order to clearly display the diagram, Fig.13 The reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0131] The detailed optical data of the eyepiece optical system 10 of the second embodiment are as follows: Fig.13 As shown, the overall system focal length of the eyepiece optical system 10 of the second embodiment is 19.795 mm, the half-eye viewing angle (ω) is 68.000°, the aperture value (Fno) is 4.949, the image height is 29.828 mm, and the SL is 35.565 mm.

[0132] like Fig.16 As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the second embodiment are shown in the formula (1).

[0133] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the second embodiment is as follows: Fig.41 shown.

[0134] The longitudinal spherical aberration diagram of the second embodiment Fig.14 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.14 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.36mm. Fig.14 B and Fig.14In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±13.00mm. Fig.14 The distortion diagram of D shows that the distortion of the second embodiment is maintained within the range of ±40%. This shows that the second embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 35.565 mm.

[0135] It can be seen from the above description that the advantages of the second embodiment over the first embodiment are: the system length of the second embodiment is shorter than the system length of the first embodiment. The aperture of the second embodiment is larger than the aperture of the first embodiment. The half-eye viewing angle of the second embodiment is larger than the half-eye viewing angle of the first embodiment. The longitudinal spherical aberration of the second embodiment is smaller than the longitudinal spherical aberration of the first embodiment. The field curvature of the second embodiment is smaller than the field curvature of the first embodiment.

[0136] Fig.17 is a schematic diagram of an eyepiece optical system of a third embodiment of the present invention, and Fig.18 A to Fig.18 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the third embodiment. Please refer to Fig.17 , a third embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the main differences between the two are as follows. The optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2 of the third embodiment and the first embodiment are more or less different. It should be noted here that in order to clearly display the drawings, Fig.17 The reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0137] The detailed optical data of the eyepiece optical system 10 of the third embodiment are as follows: Fig.19 As shown, the overall system focal length of the eyepiece optical system 10 of the third embodiment is 29.530 mm, the half-eye viewing angle (ω) is 65.000°, the aperture value (Fno) is 7.382, the image height is 29.009 mm, and the SL is 46.287 mm.

[0138] like Fig. 20 As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the third embodiment are shown in the formula (1).

[0139] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the third embodiment is as follows: Fig.41 shown.

[0140] Schematic diagram of longitudinal spherical aberration of the third embodiment Fig.18A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.18 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.53mm. Fig.18 B and Fig.18 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±2.80mm. Fig.18 The distortion diagram of D shows that the distortion of the third embodiment is maintained within the range of ±55%. This shows that the third embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 35.565 mm.

[0141] It can be seen from the above description that the advantages of the third embodiment over the first embodiment are: the aperture of the third embodiment is larger than that of the first embodiment, and the field curvature of the third embodiment is smaller than that of the first embodiment.

[0142] Fig.21 is a schematic diagram of an eyepiece optical system of a fourth embodiment of the present invention, and Fig. 22 A to Fig. 22 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the fourth embodiment. Please refer to Fig.21 , a fourth embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the main differences between the two are described as follows. The optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2 of the fourth embodiment are more or less different from those of the first embodiment. In addition, in the fourth embodiment, the display side 26 of the second lens 2 is not a Fresnel surface, but a general aspheric surface. The optical axis area 26p1 of the display side 26 of the second lens 2 is a plane, and its circumferential area 263 is a convex surface. It should be noted here that in order to clearly display the drawing, Fig.21 Part of the reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0143] The detailed optical data of the eyepiece optical system 10 of the fourth embodiment are as follows: Fig.23 As shown, the overall system focal length of the eyepiece optical system 10 of the fourth embodiment is 34.077 mm, the half-eye viewing angle (ω) is 69.000°, the aperture value (Fno) is 8.519, the image height is 33.665 mm, and the SL is 46.229 mm.

[0144] like Fig.24As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the fourth embodiment are given in formula (1). It should be noted that although the display side surface 26 is not a Fresnel surface, formula (1) is still applicable.

[0145] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the fourth embodiment is as follows: Fig.41 shown.

[0146] Schematic diagram of longitudinal spherical aberration of the fourth embodiment Fig. 22 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig. 22 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.59mm. Fig. 22 B and Fig. 22 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±4.50mm. Fig. 22 The distortion diagram of D shows that the distortion of the fourth embodiment is maintained within the range of ±60%. This shows that the fourth embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 46.229 mm.

[0147] It can be seen from the above description that the advantage of the fourth embodiment over the first embodiment is that the half-eye viewing angle of the fourth embodiment is greater than the half-eye viewing angle of the first embodiment.

[0148] Fig.25 is a schematic diagram of an eyepiece optical system of a fifth embodiment of the present invention, and Fig.26 A to Fig.26 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the fifth embodiment. Please refer to Fig.25 , a fifth embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the main differences between the two are as follows. The optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2 of the fifth embodiment and the first embodiment are more or less different. It should be noted that, in order to clearly display the drawings, Fig.25 The reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0149] The detailed optical data of the eyepiece optical system 10 of the fifth embodiment are as follows: Fig. 27As shown, the overall system focal length of the eyepiece optical system 10 of the fifth embodiment is 41.848 mm, the half-eye viewing angle (ω) is 65.000°, the aperture value (Fno) is 10.462, the image height is 33.636 mm, and the SL is 61.657 mm.

[0150] like Fig.28 As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the fifth embodiment are shown in the formula (1).

[0151] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the fifth embodiment is as follows: Fig.41 shown.

[0152] Schematic diagram of longitudinal spherical aberration of the fifth embodiment Fig.26 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.26 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.53mm. Fig.26 B and Fig.26 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±13.00mm. Fig.26 The distortion diagram of D shows that the distortion of the fifth embodiment is maintained within the range of ±62%. This shows that the fifth embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 61.657 mm.

[0153] It can be seen from the above description that the advantage of the fifth embodiment over the first embodiment is that the manufacturing difficulty of the fifth embodiment is lower, resulting in a higher yield.

[0154] Fig.29 is a schematic diagram of an eyepiece optical system of a sixth embodiment of the present invention, and Fig.30 A to Fig.30 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the sixth embodiment. Please refer to Fig.29 , a sixth embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the main differences between the two are as follows. The optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2 of the sixth embodiment are more or less different from those of the first embodiment. In addition, in the sixth embodiment, the eye side surface 15 of the first lens 1 is a convex surface, its optical axis area 151 is a convex surface, and its circumferential area 153 is a convex surface. It should be noted here that in order to clearly show the drawing, Fig.29The reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0155] The detailed optical data of the eyepiece optical system 10 of the sixth embodiment are as follows: Fig.31 As shown, the overall system focal length of the eyepiece optical system 10 of the sixth embodiment is 24.391 mm, the half-eye viewing angle (ω) is 65.000°, the aperture value (Fno) is 6.098, the image height is 23.814 mm, and the SL is 37.789 mm.

[0156] like Fig.32 As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the sixth embodiment are shown in the formula (1).

[0157] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the sixth embodiment is as follows: Fig.41 shown.

[0158] Graph showing longitudinal spherical aberration of the sixth embodiment Fig.30 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.30 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.48mm. Fig.30 B and Fig.30 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±1.60mm. Fig.30 The distortion diagram of D shows that the distortion of the sixth embodiment is maintained within the range of ±55%. This shows that the sixth embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 37.389 mm.

[0159] It can be seen from the above description that the advantages of the sixth embodiment over the first embodiment are: the aperture of the sixth embodiment is larger than that of the first embodiment. The system length of the sixth embodiment is smaller than that of the first embodiment. The field curvature of the sixth embodiment is smaller than that of the first embodiment.

[0160] Fig.33 is a schematic diagram of an eyepiece optical system of a seventh embodiment of the present invention, and Fig.34 A to Fig.34 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the seventh embodiment. Please refer to Fig.33, a seventh embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the main differences between the two are described as follows. The optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2 of the seventh embodiment are more or less different from those of the first embodiment. In addition, in the seventh embodiment, the eye-side surface 15 of the first lens 1 is a convex surface, its optical axis area 151 is a convex surface, and its circumferential area 153 is a convex surface. The optical axis area 251 of the eye-side surface 25 of the second lens 2 is a convex surface, and its circumferential area 253 is a convex surface. It should be noted here that in order to clearly display the drawings, Fig.33 The reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0161] The detailed optical data of the eyepiece optical system 10 of the seventh embodiment are as follows: Fig.35 As shown, the overall system focal length of the eyepiece optical system 10 of the seventh embodiment is 33.108 mm, the half-eye viewing angle (ω) is 67.500°, the aperture value (Fno) is 8.277, the image height is 36.000 mm, and the SL is 50.215 mm.

[0162] like Fig.36 As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the seventh embodiment are shown in the formula (1).

[0163] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the seventh embodiment is as follows: Fig.41 shown.

[0164] Graph showing longitudinal spherical aberration of the seventh embodiment Fig.34 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.34 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.49mm. Fig.34 B and Fig.34 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±23.00mm. Fig.34 The distortion diagram of D shows that the distortion of the seventh embodiment is maintained within the range of ±55%. This shows that the seventh embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 50.215 mm.

[0165] It can be seen from the above description that the advantage of the seventh embodiment over the first embodiment is that the half-eye viewing angle of the seventh embodiment is greater than the half-eye viewing angle of the first embodiment.

[0166] Fig.37 is a schematic diagram of an eyepiece optical system of an eighth embodiment of the present invention, and Fig.38 A to Fig.38 D is the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system of the eighth embodiment. Please refer to Fig.37 , an eighth embodiment of the eyepiece optical system 10 of the present invention is substantially similar to the first embodiment, and the main differences between the two are described as follows. The optical data, aspheric coefficients, and parameters of the first lens 1 to the second lens 2 of the eighth embodiment are more or less different from those of the first embodiment. In addition, in the eighth embodiment, the eye-side surface 15 of the first lens 1 is a concave surface, its optical axis area 152 is a concave surface, and its circumferential area 154 is a concave surface. The optical axis area 252 of the eye-side surface 25 of the second lens 2 is a concave surface, and its circumferential area 254 is a concave surface. It should be noted here that in order to clearly display the drawings, Fig.37 The reference numerals of the optical axis area and the circumferential area similar to those in the first embodiment are omitted.

[0167] The detailed optical data of the eyepiece optical system 10 of the eighth embodiment are as follows: Fig.39 As shown, the overall system focal length of the eyepiece optical system 10 of the eighth embodiment is 32.784 mm, the half-eye viewing angle (ω) is 67.500°, the aperture value (Fno) is 37.517, the image height is 35.995 mm, and the SL is 50.517 mm.

[0168] like Fig.40 As shown in FIG. 1 , the aspheric coefficients of the display side surfaces 16 and 26 of the first lens 1 to the second lens 2 in the eighth embodiment are shown in the formula (1).

[0169] In addition, the relationship between the important parameters in the eyepiece optical system 10 of the eighth embodiment is as follows: Fig.41 shown.

[0170] Schematic diagram of the longitudinal spherical aberration of the eighth embodiment Fig.38 A is simulated when the pupil radius is 2.000 mm (i.e., when the exit pupil diameter EPD of the eyepiece optical system 10 is 4.000 mm). Fig.38 In A, the imaging point deviation of off-axis light at different heights is controlled within the range of ±0.49mm. Fig.38 B and Fig.38 In the two field curvature aberration diagrams of C, the field curvature aberrations of the three representative wavelengths in the entire field of view fall within the range of ±23.00mm. Fig.38 The distortion diagram of D shows that the distortion of the eighth embodiment is maintained within the range of ±55%. This shows that the eighth embodiment can still provide better imaging quality compared to the existing eyepiece optical system when the SL is shortened to about 50.517 mm.

[0171] It can be seen from the above description that the advantage of the eighth embodiment over the first embodiment is that the half-eye viewing angle of the eighth embodiment is greater than the half-eye viewing angle of the first embodiment.

[0172] Also refer to Fig.41 . Fig.41 The table diagram of various optical parameters of the first to eighth embodiments described above. Among the parameters in the columns "EFL" to "TL", except for "ω" which is in degree (°), and "V1" and "V2" which are dimensionless, the units of the parameters in other columns are millimeters (mm). Among the parameters in the columns "ω / TL" to "EFL / TL", except for "ω / TL" which is in degree / mm, the units of the parameters in other columns are dimensionless.

[0173] For the following conditional expressions, at least one of them is intended to maintain the system focal length and optical parameters at an appropriate value, to avoid any parameter being too large and thus detrimental to the correction of the aberration of the entire eyepiece optical system 10, or to avoid any parameter being too small and thus affecting assembly or increasing the difficulty of manufacturing.

[0174] in,

[0175] The eyepiece optical system 10 may meet the conditional formula: 6.000≦EFL / T1, and a preferred range is 6.000≦EFL / T1≦24.000.

[0176] The eyepiece optical system 10 may meet the condition: 6.000≦EFL / T2, and a preferred range is 6.000≦EFL / T2≦24.000.

[0177] The eyepiece optical system 10 may meet the conditional formula: 4.490≦EFL / ALT, and a preferred range is 4.490≦EFL / ALT≦12.000.

[0178] The eyepiece optical system 10 may meet the conditional formula: 4.300≦EFL / TL, and a preferred range is 4.300≦EFL / TL≦12.000.

[0179] For the following conditional expressions, at least one of them is intended to maintain the thickness and spacing of each lens at an appropriate value, to avoid any parameter being too large and thus detrimental to the overall thinning of the eyepiece optical system 10, or to avoid any parameter being too small and thus affecting assembly or increasing the difficulty of manufacturing.

[0180] in,

[0181] The eyepiece optical system 10 may meet the conditional formula: 0.400≦T1 / T2, and a preferred range is 0.400≦T1 / T2≦2.000.

[0182] The eyepiece optical system 10 may meet the conditional formula: 1.500≦T1 / G12, and a preferred range is 1.500≦T1 / G12≦19.000.

[0183] The eyepiece optical system 10 may meet the conditional formula: 1.800≦T2 / G12, and a preferred range is 1.800≦T2 / G12≦19.000.

[0184] The eyepiece optical system 10 may meet the conditional formula: 4.630≦TTL / ALT, and a preferred range is 4.630≦TTL / ALT≦13.500.

[0185] The eyepiece optical system 10 may meet the conditional formula: 4.340≦TTL / TL, and a preferred range is 4.340≦TTL / TL≦12.000.

[0186] The eyepiece optical system 10 may meet the conditional formula: 5.500≦G2D / T1, and a preferred range is 5.500≦G2D / T1≦22.000.

[0187] The eyepiece optical system 10 may meet the conditional formula: 5.500≦G2D / T2, and a preferred range is 5.500≦G2D / T2≦22.000.

[0188] In addition, any combination of embodiment parameters can be selected to increase system restrictions, so as to facilitate the system design of the same structure of the present invention. In view of the unpredictability of optical system design, under the structure of the present invention, meeting the above conditional formula can better shorten the length of the present invention, increase the aperture, improve the imaging quality, or improve the assembly yield, thereby improving the shortcomings of the prior art.

[0189] In addition, the exemplary limiting relationship formulas listed above can also be arbitrarily and selectively combined in different quantities and applied to the implementation of the present invention, and are not limited thereto. When implementing the present invention, in addition to the aforementioned relationship formulas, other lens concave and convex surface arrangements and other detailed structures can also be designed for the lens to enhance the control of system performance and / or resolution. It should be noted that these details need to be selectively combined and applied to other embodiments of the present invention without conflict.

[0190] The numerical ranges obtained by the combination ratio relationship of the optical parameters disclosed in each embodiment of the present invention, including the maximum and minimum values, can be implemented accordingly.

[0191] In summary, the eyepiece optical system 10 of the embodiment of the present invention can achieve the following effects and advantages:

[0192] 1. The longitudinal spherical aberration, astigmatism, and distortion of each embodiment of the present invention all meet the use specifications. In addition, the off-axis light rays of the three representative wavelengths of red, green, and blue at different heights are all concentrated near the imaging point. From the deflection amplitude of each curve, it can be seen that the imaging point deviation of the off-axis light rays at different heights is controlled and has good spherical aberration, aberration, and distortion suppression capabilities. Further referring to the imaging quality data, the distances between the three representative wavelengths of red, green, and blue are also quite close, indicating that the present invention has good concentration of light rays of different wavelengths under various conditions and has excellent dispersion suppression capabilities, and can produce excellent imaging quality.

[0193] 2. The eyepiece optical system 10 of the embodiment of the present invention is designed by the following lens combination: (1) The optical axis region 161 of the display side surface 16 of the first lens 1 is a convex surface and the display side surface 16 is a Fresnel surface F. (2) The optical axis region 261 or the circumferential region 263 of the display side surface 26 of the second lens 2 is a convex surface. In addition, the combination of the conditional formula 6.500° / mm≦ω / TL≦30.000° / mm, 0.970≦D1 / D2≦1.500 or 0.850≦D3 / D2≦1.400 will make the focusing and imaging of the eyepiece optical system 10 shared by two lenses that tend to have positive refractive power, which is beneficial to increase the half-eye viewing angle of the system without increasing the volume and weight of the system and at the same time maintain the size of the display screen 99.

[0194] 3. When the display side surface 26 of the second lens 2 is a Fresnel surface F, the problem of thinning the circumferential area of ​​the lens and making it difficult to assemble when the refractive index of the circumferential area is increased to achieve a viewing angle of most eyes can be solved, and the volume and weight of the second lens 2 can be reduced.

[0195] Fourth, when the eye side surface 15 of the first lens 1 is a convex surface, the image quality in the center of the display screen 99 is better, and the refractive index of the Fresnel surface F of the display side surface 16 can be reduced to improve the yield. When the eye side surface 15 of the first lens 1 is a concave surface, because the concave surface conforms to the structure of the convex surface of the human eye, the comfort of the observer can be improved. In addition, the image quality around the display screen 99 is better, and the half-eye viewing angle is easier to improve. When the eye side surface 15 of the first lens 1 is a flat surface, it is easier to balance the image quality between the center and the periphery of the display screen 99, and it is easier to manufacture and improve the yield.

[0196] 5. When the conditional expression 4.000≦D4 / ALT or the conditional expression 3.750≦D4 / TL is satisfied and combined with the above surface shape combination, it is beneficial to increase the optical effective diameter of the lens without increasing the thickness of the lens. The above conditional expressions are preferably limited to 4.000≦D4 / ALT≦19.500 and 3.750≦D4 / TL≦17.400 respectively.

[0197] 6. When the conditional expression 1.100≦ω / arctan(D4 / EFL) is satisfied and combined with the above face shape combination, it is beneficial to increase the half-eye viewing angle of the system and reduce the size of the display screen 99 at the same time. The conditional expression is preferably limited to 1.100≦ω / arctan(D4 / EFL)≦2.250. Among them, arctan represents the inverse tangent function.

[0198] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. An eyepiece optical system, used for allowing imaging light to enter an observer's eye from a display screen through the eyepiece optical system to form an image, wherein the direction toward the eye is an eye side, and the direction toward the display screen is a display side, and the system includes a first lens and a second lens in sequence along an optical axis from the eye side to the display side, wherein the first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through; The first lens has a positive refractive power, an optical axis region of the display side surface of the first lens is a convex surface, and the display side surface of the first lens is a Fresnel surface; The second lens has a positive refractive power, the optical axis region or the circumferential region of the display side of the second lens is a convex surface, and the circumferential region of the eye side of the second lens is a flat surface; The eyepiece optical system has only the two lenses mentioned above; and The eyepiece optical system meets the following conditions: 0.400≦T1 / T2≦2.000, and 1.800≦T2 / G12≦19.000, in, T1 is a thickness of the first lens on the optical axis, T2 is a thickness of the second lens on the optical axis, and G12 is an air gap from the first lens to the second lens on the optical axis.

2. An eyepiece optical system, used for allowing imaging light to enter an observer's eye from a display screen through the eyepiece optical system to form an image, wherein the direction toward the eye is an eye side, and the direction toward the display screen is a display side, and the system includes a first lens and a second lens in sequence along an optical axis from the eye side to the display side, wherein the first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through; The first lens has a positive refractive power, an optical axis region of the display side surface of the first lens is a convex surface, the display side surface of the first lens is a Fresnel surface, and the optical axis region of the eye side surface of the first lens is a plane; The second lens has a positive refractive power, the optical axis region or the circumferential region of the display side of the second lens is a convex surface, and the optical axis region of the eye side of the second lens is a flat surface; The eyepiece optical system has only the two lenses mentioned above; and The eyepiece optical system meets the following conditions: 0.400≦T1 / T2≦2.000, and 1.800≦T2 / G12≦19.000, in, T1 is a thickness of the first lens on the optical axis, T2 is a thickness of the second lens on the optical axis, and G12 is an air gap from the first lens to the second lens on the optical axis.

3. An eyepiece optical system, used for allowing imaging light to enter an observer's eye from a display screen through the eyepiece optical system to form an image, wherein the direction toward the eye is an eye side, and the direction toward the display screen is a display side, and the system includes a first lens and a second lens in sequence along an optical axis from the eye side to the display side, wherein the first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through; The first lens has a positive refractive power, an optical axis region of the display side of the first lens is a convex surface, the display side of the first lens is a Fresnel surface, and a circumferential region of the eye side of the first lens is a plane; The second lens has a positive refractive power, the optical axis region or the circumferential region of the display side of the second lens is a convex surface, and the optical axis region of the eye side of the second lens is a flat surface; The eyepiece optical system has only the two lenses mentioned above; and The eyepiece optical system meets the following conditions: 0.400≦T1 / T2≦2.000, and 1.800≦T2 / G12≦19.000, in, T1 is a thickness of the first lens on the optical axis, T2 is a thickness of the second lens on the optical axis, and G12 is an air gap from the first lens to the second lens on the optical axis.

4. The eyepiece optical system as claimed in any one of claims 1 to 3, wherein the eyepiece optical system further meets the following conditional expression: 6.000≦EFL / T1, where EFL is a system focal length of the eyepiece optical system.

5. The eyepiece optical system as claimed in any one of claims 1 to 3, wherein the eyepiece optical system further meets the following conditional expression: 6.000≦EFL / T2, where EFL is a system focal length of the eyepiece optical system.

6. The eyepiece optical system as claimed in any one of claims 1 to 3, wherein the eyepiece optical system further meets the following conditional formula: 4.300≦EFL / TL, EFL is a system focal length of the eyepiece optical system, and TL is a distance from the eye side of the first lens to the display side of the second lens on the optical axis.

7. The eyepiece optical system as claimed in any one of claims 1 to 3, wherein the eyepiece optical system further meets the following conditional formula: 4.490≦EFL / ALT, EFL is a system focal length of the eyepiece optical system, and ALT is a sum of thicknesses of the first lens and the second lens on the optical axis.

8. An eyepiece optical system, used for allowing imaging light to enter an observer's eye from a display screen through the eyepiece optical system to form an image, wherein the direction toward the eye is an eye side, and the direction toward the display screen is a display side, and the system includes a first lens and a second lens in sequence along an optical axis from the eye side to the display side, wherein the first lens and the second lens each include an eye side surface facing the eye side and allowing the imaging light to pass through, and a display side surface facing the display side and allowing the imaging light to pass through; The first lens has a positive refractive power, an optical axis region of the display side surface of the first lens is a convex surface, and the display side surface of the first lens is a Fresnel surface; The second lens has a positive refractive power, the optical axis region or the circumferential region of the display side of the second lens is a convex surface, and the optical axis region of the eye side of the second lens is a flat surface; The eyepiece optical system has only the two lenses mentioned above; and The eyepiece optical system meets the following conditions: 0.400≦T1 / T2≦2.000, 6.000≦EFL / T1, and 1.800≦T2 / G12≦19.000, in, T1 is a thickness of the first lens on the optical axis, T2 is a thickness of the second lens on the optical axis, EFL is a system focal length of the eyepiece optical system, and G12 is an air gap from the first lens to the second lens on the optical axis.

9. The eyepiece optical system of claim 1 , wherein the eyepiece optical system further meets the following conditional expression: 6.500° / mm≦ω / TL≦30.000° / mm, ω is half of the eye viewing angle of the eyepiece optical system, and TL is a distance from the eye side of the first lens to the display side of the second lens on the optical axis.

10. The eyepiece optical system as described in claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following condition: 1.500≦T1 / G12≦19.

000.

11. The eyepiece optical system of claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following condition: 4.630≦TTL / ALT, wherein: TTL is a distance from the eye side of the first lens to the display screen on the optical axis, and ALT is a total thickness of the first lens and the second lens on the optical axis.

12. The eyepiece optical system of claim 1 , 2 , 3 or 8 , wherein the eyepiece optical system further satisfies the following conditional formula: 4.340≦TTL / TL, TTL is a distance from the eye side of the first lens to the display screen on the optical axis, and TL is a distance from the eye side of the first lens to the display side of the second lens on the optical axis.

13. The eyepiece optical system as claimed in claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following condition: 5.500≦G2D / T1, G2D is a distance from the second lens to the display screen on the optical axis.

14. The eyepiece optical system as claimed in claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following condition: 5.500≦G2D / T2, G2D is a distance from the second lens to the display screen on the optical axis.

15. The eyepiece optical system of claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following condition: 0.970≦D1 / D2≦1.500, D1 is the longest distance of the eye-side surface of the first lens through the center of the Fresnel surface, and D2 is the longest side of the display screen.

16. An eyepiece optical system as described in claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following conditional formula: 3.750≦D4 / TL, D4 is a longest distance from the display side of the first lens from the center of the Fresnel surface to the circumference of the first lens, and TL is a distance from the eye side of the first lens to the display side of the second lens on the optical axis.

17. The eyepiece optical system of claim 1, 2, 3 or 8, wherein the eyepiece optical system further meets the following conditional expression: 4.000≦D4 / ALT, wherein: D4 is the longest distance of the display side surface of the first lens from the center of the Fresnel surface to the circumference of the first lens, and ALT is the sum of the thicknesses of the first lens and the second lens on the optical axis.

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