Eyepiece optical system

Abstract

The present invention discloses an eyepiece optical system. The eyepiece optical system includes a first lens, a second lens, a third lens, and a fourth lens in sequence from the eye side to the display side. By designing the concave-convex configuration of the surfaces of the four lenses, the overall length of the eyepiece optical system is shortened while taking into account better optical performance, shorter effective focal length, and larger field of view.

Description

[0001] This invention patent application is a divisional application. The application number of the original application is 201710021201.3, the application date is January 11, 2017, and the invention name is: Eyepiece optical system. Technical Field

[0002] The invention relates to an eyepiece optical system, in particular to a four-piece eyepiece optical system. Background Art

[0003] As technology advances, consumers are increasingly demanding miniaturized electronic products. Features applied to eyepiece optical systems, key components of eyepiece optical systems incorporated into consumer electronic products, should keep pace with technology to meet consumer expectations. Some important features of eyepiece optical systems include image quality and size. Improvements in image sensor technology play an important role in maintaining (or improving) consumer expectations for image quality under the conditions of miniaturization. However, current eyepiece optical systems have some disadvantages, such as too small field of view and / or too large aberrations. Furthermore, it is a great challenge to reduce the size of the imaging lens while maintaining good optical properties.

[0004] In view of this, there is a need for an improved eyepiece optical system that has a larger field of view and also has good imaging quality. Summary of the invention

[0005] The present invention provides an eyepiece optical system. By controlling the concave-convex configuration of four lens surfaces, the length of the eyepiece optical system is shortened while also taking into account good optical properties and imaging quality.

[0006] In the disclosure of the specification, the parameters listed in the following table are used, but are not limited to use only these parameters, as shown in Table 1.

[0007] Table 1 Parameters

[0008]

[0009]

[0010] In one embodiment of the present invention, the eyepiece optical system includes a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side. In addition, each lens has an eye side surface facing the eye side, a display side surface facing the display side, and a central thickness along the optical axis. The first lens has a positive refractive power, and the display side surface of the first lens includes a convex portion located in the vicinity of the optical axis; the second lens has a positive refractive power or the fourth lens has a negative refractive power; the third lens has a negative refractive power; the lenses of the eyepiece optical system only have the above four lenses and meet the following conditional formula: EFL / G4D≧2.4.

[0011] In one embodiment of the present invention, the eyepiece optical system includes a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side. In addition, each lens has an eye side surface facing the eye side, a display side surface facing the display side, and a center thickness along the optical axis. The first lens has a positive refractive power, and the display side surface of the first lens includes a convex portion located in a region near the circumference; the second lens has a positive refractive power or the fourth lens has a negative refractive power; the third lens has a negative refractive power; the lenses of the eyepiece optical system only have the above four lenses and meet the following conditional formula: EFL / G4D≧2.4.

[0012] In the above embodiment, some optical parameters may be selectively controlled to satisfy at least one of the following conditions:

[0013] 0≦TL / ER≦8 conditional expression (1);

[0014] 0≦TTL / ER≦10 conditional expression (2);

[0015] In one embodiment of the present invention, the eyepiece optical system includes a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side. In addition, each lens has an eye side surface facing the eye side, a display side surface facing the display side, and a central thickness along the optical axis. The first lens has a positive refractive power, and the display side surface of the first lens includes a convex portion located in a region near the circumference; the second lens has a positive refractive power; the third lens has a negative refractive power or the fourth lens has a negative refractive power; the lenses of the eyepiece optical system only have the above four lenses and meet the following conditional formulas: EFL / G4D≧2.4 and 0≦TL / ER≦8.

[0016] In one embodiment of the present invention, the eyepiece optical system includes a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side. In addition, each lens has an eye side surface facing the eye side, a display side surface facing the display side, and a center thickness along the optical axis. The first lens has a positive refractive power, and the display side surface of the first lens includes a convex portion located in a region near the optical axis; the second lens has a positive refractive power, and the eye side surface of the second lens includes a convex portion located in a region near the circumference; the third lens has a negative refractive power or the fourth lens has a negative refractive power; the lenses of the eyepiece optical system only have the above four lenses and meet the following conditional formulas: EFL / G4D≧2.4 and 0≦TL / ER≦8.

[0017] In the above embodiment, some optical parameters may be selectively controlled to satisfy at least one of the following conditions:

[0018] ALT / AAG ≦ 10 Condition (3);

[0019] (T1+G12+T2) / (T3+G34+T4)≦2.5 Conditional formula (4);

[0020] (T3+T4) / G34≦3.0 Condition (5);

[0021] T2 / T1≧0.9 Condition (6);

[0022] T2 / (G23+G34)≦4.0 Condition (7);

[0023] T1 / G34≦3.0 Condition (8);

[0024] EFL / AAG≧4.9 Condition (9);

[0025] T1 / (G23+G34)≦2.5 Conditional formula (10);

[0026] (T1+T3) / T4≦4.5 Conditional formula (11).

[0027] Wherein TL represents the distance from the eye side of the first lens to the display side of the fourth lens on the optical axis, ER represents the distance from the pupil of the observer to the eye side of the first lens on the optical axis; T1 represents the center thickness of the first lens on the optical axis, T2 represents the center thickness of the second lens on the optical axis, G12 represents the air gap width between the first lens and the second lens on the optical axis, G23 represents the air gap width between the second lens and the third lens on the optical axis, G34 represents the air gap width between the third lens and the fourth lens on the optical axis. Gap width; T3 represents the center thickness of the third lens on the optical axis, T4 represents the center thickness of the fourth lens on the optical axis; ALT represents the sum of the center thicknesses of the four lenses from the first lens to the fourth lens on the optical axis, AAG represents the sum of the three air gap widths from the first lens to the fourth lens on the optical axis; EFL represents the effective focal length of the eyepiece optical system, G4D represents the distance from the display side of the fourth lens to the display screen on the optical axis, wherein TTL represents the distance from the eye side of the first lens to the display screen on the optical axis.

[0028] When implementing the present invention, in addition to the above conditional expressions, other lens concave-convex surface arrangement and other detailed structures may be additionally designed for a single lens or for multiple lenses in general 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, and are not limited thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the eyepiece optical system of the present invention.

[0030] Figure 2 It is a schematic diagram of the cross-sectional structure of a lens according to an embodiment of the present invention.

[0031] Figure 3 Schematic diagram of the relationship between lens surface shape and light focus.

[0032] Figure 4 FIG. 4 is a graph showing the relationship between the lens surface shape and the effective radius of Example 1.

[0033] Figure 5 FIG. 4 is a graph showing the relationship between the lens surface shape and the effective radius of Example 2.

[0034] Figure 6 This is a graph showing the relationship between the lens surface shape and the effective radius of Example 3.

[0035] Figure 7 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the first embodiment of the present invention.

[0036] Figure 8 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the first embodiment of the present invention.

[0037] Fig. 9 This is a table diagram showing detailed optical data of each lens of the eyepiece optical system of the first embodiment of the present invention.

[0038] Fig.10 This is a table diagram of aspheric surface data of the eyepiece optical system of the first embodiment of the present invention.

[0039] Fig.11 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the second embodiment of the present invention.

[0040] Fig.12 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the second embodiment of the present invention.

[0041] Fig.13 This is a table diagram showing detailed optical data of each lens of the eyepiece optical system of the second embodiment of the present invention.

[0042] Fig.14 This is a table diagram of aspheric surface data of the eyepiece optical system of the second embodiment of the present invention.

[0043] Fig.15 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the third embodiment of the present invention.

[0044] Fig.16 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the third embodiment of the present invention.

[0045] Fig.17 This is a table diagram showing detailed optical data of each lens of the eyepiece optical system of the third embodiment of the present invention.

[0046] Fig.18 This is a table diagram of aspheric surface data of the eyepiece optical system of the third embodiment of the present invention.

[0047] Fig.19 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the fourth embodiment of the present invention.

[0048] Fig. 20 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the fourth embodiment of the present invention.

[0049] Fig.21 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the fourth embodiment of the present invention.

[0050] Fig. 22This is a table diagram of aspheric surface data of the eyepiece optical system of the fourth embodiment of the present invention.

[0051] Fig.23 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the fifth embodiment of the present invention.

[0052] Fig.24 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the fifth embodiment of the present invention.

[0053] Fig.25 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the fifth embodiment of the present invention.

[0054] Fig.26 This is a table diagram of aspheric surface data of the eyepiece optical system of the fifth embodiment of the present invention.

[0055] Fig. 27 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the sixth embodiment of the present invention.

[0056] Fig.28 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the sixth embodiment of the present invention.

[0057] Fig.29 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the sixth embodiment of the present invention.

[0058] Fig.30 This is a table diagram of aspheric surface data of the eyepiece optical system of the sixth embodiment of the present invention.

[0059] Fig.31 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the seventh embodiment of the present invention.

[0060] Fig.32 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the seventh embodiment of the present invention.

[0061] Fig.33 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the seventh embodiment of the present invention.

[0062] Fig.34 This is a table diagram of aspheric surface data of the eyepiece optical system of the seventh embodiment of the present invention.

[0063] Fig.35 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the eighth embodiment of the present invention.

[0064] Fig.36 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the eighth embodiment of the present invention.

[0065] Fig.37 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the eighth embodiment of the present invention.

[0066] Fig.38 This is a table diagram of aspheric surface data of the eyepiece optical system of the eighth embodiment of the present invention.

[0067] Fig.39 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the ninth embodiment of the present invention.

[0068] Fig.40 Schematic diagram of longitudinal spherical aberration and various aberrations of the eyepiece optical system of the ninth embodiment of the present invention.

[0069] Fig.41 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the ninth embodiment of the present invention.

[0070] Fig.42 This is a table diagram of aspheric surface data of the eyepiece optical system of the ninth embodiment of the present invention.

[0071] Fig.43 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the tenth embodiment of the present invention.

[0072] Fig.44 Schematic diagram of the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the tenth embodiment of the present invention.

[0073] Fig.45 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the tenth embodiment of the present invention.

[0074] Fig.46 This is a table diagram of aspheric surface data of the eyepiece optical system of the tenth embodiment of the present invention.

[0075] Fig.47 It is a schematic diagram of the lens cross-sectional structure of the eyepiece optical system of the eleventh embodiment of the present invention.

[0076] Fig.48 Schematic diagram of the longitudinal spherical aberration and various aberrations of the eyepiece optical system of the eleventh embodiment of the present invention.

[0077] Fig.49 This is a table diagram of detailed optical data of each lens of the eyepiece optical system of the eleventh embodiment of the present invention.

[0078] Fig.50 This is a table diagram of aspheric surface data of the eyepiece optical system of the eleventh embodiment of the present invention.

[0079] Fig.51This is a table comparing the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34 and EFL / AAG of Examples 1-6 of the present invention.

[0080] Fig.52 This is a table comparing the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34 and EFL / AAG of Examples 7-11 of the present invention. DETAILED DESCRIPTION

[0081] In order to more fully understand the contents of the specification and its advantages, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, those with ordinary knowledge in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0082] Description of symbols in the accompanying drawings:

[0083] 1,2,3,4,5,6,7,8,9,10',11',V100 eyepiece optical system; 110,210,310,410,510,610,710,810,910,10'10,11'10 first lens; 111,121,131,141,211,221,231,241,311,321,331,341,411,421,431,441,511,521,531,541,611,621,631,641,711,721,731,741,811,821,831,841,911,921,931,941,10'11 ,10'21,10'31,10'41,11'11,11'21,11'31,11'41 side view; 112,122,132,142,212,222,232,242,312,322,332,342,412,422,432,442,512,522,532,542,612,622,632,642,712,722,732,742,812,822,832,842,912,922,932,942,10'12,10'22,10'32,10'42,11'12,11'22,11'32,11'42 display Side; 120, 220, 320, 420, 520, 620, 720, 820, 920, 10'20, 11'20 Second lens; 130, 230, 330, 430, 530, 630, 730, 830, 930, 10'30, 11'30 Third lens; 140, 240, 340, 440, 540, 640, 740, 840, 940, 10'40, 11'40 Fourth lens; 150, 250, 350, 450, 550, 650, 750, 850, 950, 10'50, 11'50 Display screen; 1121, 1211, 1221 Convex portion near the optical axis; 112 2,1212,1222,1422,2322,3322,4412,6322,7322,8322,9412,10'412 convex portion near the circumference; 1111,1311,1321,1411,1421 concave portion near the optical axis; 1112,1312,1322,1412,7422 concave portion near the circumference; d1,d2,d3,d4 air gap; VI imaging light; V50 display screen; V60 eye; VD clear vision distance; VV magnified virtual image; A1 eye side; A2 display side; I optical axis; A area near the optical axis; C area near the circumference; E extension; Lc chief light; Lm marginal light.

[0084] 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 clear vision 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.

[0085] The term "a lens having a positive refractive power (or a negative refractive power)" as used in this specification means that the refractive power of the lens on the optical axis calculated by Gaussian optical theory is positive (or negative). The eye side and display side are defined as the range through which the imaging light passes, wherein the imaging light includes the chief ray Lc and the marginal ray Lm. Figure 2 As shown, I is the optical axis and the lens is radially symmetrical with the optical axis I as the symmetry axis. The area on the optical axis where the light passes is the area A near the optical axis, and the area where the edge light passes is the area C near the circumference. In addition, the lens also includes an extension E (i.e., the area radially outward of the area C near the circumference) for assembling the lens in an optical imaging lens. The ideal imaging light does not pass through the extension E, but the structure and shape of the extension E are not limited thereto. The following embodiments omit some of the extensions for simplicity of the drawings. In more detail, the method for determining the range of the surface shape or the area near the optical axis, the area near the circumference, or multiple areas is as follows:

[0086] 1. Please refer to Figure 2 , which is a cross-sectional view of a lens in the radial direction. From the cross-sectional view, when judging the range of the aforementioned area, a center point is defined as an intersection point on the lens surface with the optical axis, and a conversion point is a point located on the lens surface, and a tangent line passing through the point is perpendicular to the optical axis. If there are multiple conversion points radially outward, they are in order of the first conversion point, the second conversion point, and the conversion point farthest from the optical axis in the radial direction on the effective radius is the Nth conversion point. The range between the center point and the first conversion point is the area near the optical axis, and the area radially outward from the Nth conversion point is the area near the circumference, and different areas in the middle can be distinguished according to each conversion point. In addition, the effective radius is the vertical distance from the intersection point of the edge light ray Lm with the lens surface to the optical axis I.

[0087] 2. If Figure 3 As shown, the shape of the area is determined by the intersection of the light (or the extended line of the light) passing through the area in parallel with the optical axis on the eye side or the display side (light focus determination method). For example, when the light passes through the area, the light will focus toward the display side, and the focus with the optical axis will be on the display side, such as Figure 3If the light passes through the area, it will diverge, and the extension line and the focus of the optical axis are on the eye side, for example Figure 3 If the center point is M, the area is the concave part, so the area from the center point to the first conversion point is the convex part, and the area radially outward from the first conversion point is the concave part; Figure 3 It can be known that the conversion point is the boundary point where the convex part turns into the concave part. Therefore, the area and the area inside the area adjacent to the area in the radial direction can be defined as having different surface shapes with the conversion point as the boundary. In addition, if the surface shape of the area near the optical axis is to be judged by the judgment method of ordinary knowledgeable people in this field, the positive and negative R value (referring to the curvature radius of the paraxial axis, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the convexity and concavity. For the side surface of the eye, when the R value is positive, it is judged as a convex part, and when the R value is negative, it is judged as a concave part; for the display side, when the R value is positive, it is judged as a concave part, and when the R value is negative, it is judged as a convex part. The convexity and concavity determined by this method are the same as the method of determining the focus of light.

[0088] 3. If there is no conversion point on the lens surface, the area near the optical axis is defined as 0 to 50% of the effective radius, and the area near the circumference is defined as 50 to 100% of the effective radius.

[0089] Figure 4 The display side surface of the lens of Example 1 has only the first conversion point on the effective radius, so the first area is the area near the optical axis, and the second area is the area near the circumference. The R value of the eye side of this lens is positive, so it is judged that the area near the optical axis has a concave portion; the surface shape of the area near the circumference is different from the inner area adjacent to the area in the radial direction. That is, the surface shape of the area near the circumference is different from that of the area near the optical axis; the area near the circumference has a convex portion.

[0090] Figure 5 The eye side surface of the lens of Example 2 has the first and second conversion points on the effective radius, so the first area is the area near the optical axis, and the third area is the area near the circumference. The R value of the eye side surface of this lens is positive, so the area near the optical axis is judged to be a convex part; the area between the first conversion point and the second conversion point (the second area) has a concave part, and the area near the circumference (the third area) has a convex part.

[0091] Figure 6 The eye side surface of the lens of Example 3 has no transition point on the effective radius. At this time, the effective radius 0% to 50% is the area near the optical axis, and 50% to 100% is the area near the circumference. Since the R value of the area near the optical axis is positive, the eye side surface has a convex portion in the area near the optical axis; and there is no transition point between the area near the circumference and the area near the optical axis, so the area near the circumference has a convex portion.

[0092] In order to illustrate that the eyepiece optical system of the present invention can indeed achieve good optical performance while shortening the overall length, the following provides a number of embodiments and their detailed optical data. Figures 7 to 10 ,in Figure 7 FIG. 1 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a first embodiment of the present invention. Figure 8 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the first embodiment of the present invention. Fig. 9 Detailed optical data of the eyepiece optical system according to the first embodiment of the present invention are shown. Fig.10 The aspheric surface data of each lens of the eyepiece optical system according to the first embodiment of the present invention are shown. The eyepiece optical system according to the first embodiment of the present invention is suitable for allowing an imaging light of a display screen to enter an observer's eye P through the eyepiece optical system to form an image.

[0093] like Figure 7 As shown, the eyepiece optical system 1 of this embodiment includes a first lens 110, a second lens 120, a third lens 130 and a fourth lens 140 in sequence along an optical axis from the eye side A1 to the display side A2. A display screen 150 is disposed on the display side A2 of the eyepiece optical system 1. The first lens 110, the second lens 120, the third lens 130 and the fourth lens 140 respectively include an eye side surface 111 / 121 / 131 / 141 facing the eye side A1 and a display side surface 112 / 122 / 132 / 142 facing the display side A2.

[0094] In this embodiment, the detailed structure of each lens of the eyepiece optical system 1 can be referred to the drawings. The first lens 110 , the second lens 120 , the third lens 130 , and the fourth lens 140 can be made of plastic material, for example.

[0095] In the first embodiment, the first lens 110 has a positive refractive power. The eye-side surface 111 includes a concave portion 1111 located in the vicinity of the optical axis and a concave portion 1112 located in the vicinity of the circumference of the first lens 110. The display-side surface 112 includes a convex portion 1121 located in the vicinity of the optical axis and a convex portion 1122 located in the vicinity of the circumference of the first lens 110. Both the eye-side surface 111 and the display-side surface 112 are aspherical surfaces.

[0096] The second lens 120 has a positive refractive power. The eye-side surface 121 includes a convex portion 1211 located in the vicinity of the optical axis and a convex portion 1212 located in the vicinity of the circumference of the second lens 120. The display-side surface 122 includes a convex portion 1221 located in the vicinity of the optical axis and a convex portion 1222 located in the vicinity of the circumference of the second lens 120. Both the eye-side surface 121 and the display-side surface 122 are aspherical surfaces.

[0097] The third lens 130 has a negative refractive power. The eye-side surface 131 includes a concave portion 1311 located in the vicinity of the optical axis and a concave portion 1312 located in the vicinity of the circumference of the third lens 130. The display-side surface 132 includes a concave portion 1321 located in the vicinity of the optical axis and a concave portion 1322 located in the vicinity of the circumference of the third lens 130. Both the eye-side surface 131 and the display-side surface 132 are aspherical surfaces.

[0098] The fourth lens 140 has a negative refractive power. The eye-side surface 141 includes a concave portion 1411 located in the vicinity of the optical axis and a concave portion 1412 located in the vicinity of the circumference of the fourth lens 140. The display-side surface 142 includes a concave portion 1421 located in the vicinity of the optical axis and a convex portion 1422 located in the vicinity of the circumference of the fourth lens 140. Both the eye-side surface 141 and the display-side surface 142 are aspherical surfaces.

[0099] In the present embodiment, air gaps are designed to exist between the first to fourth lenses 110, 120, 130, and 140, such as: there is an air gap d1 between the first lens 110 and the second lens 120, an air gap d2 between the second lens 120 and the third lens 130, an air gap d3 between the third lens 130 and the fourth lens 140, and an air gap d4 between the fourth lens 140 and the display screen 150. However, in other embodiments, none of the aforementioned air gaps may be present, such as: the surface profiles of the two opposing lenses are designed to correspond to each other and fit together to eliminate the air gaps therebetween. It can be seen that the air gap d1 is G12, the air gap d2 is G23, the air gap d3 is G34, the air gap d4 is G4D, and the sum of the air gaps d1, d2, and d3 is AAG. For the optical properties of each lens in the eyepiece optical system 1 of the present embodiment, please refer to Fig. 9 .

[0100] The eight aspherical surfaces, namely, the eye-side surface 111 and the display-side surface 112 of the first lens 110, the eye-side surface 121 and the display-side surface 122 of the second lens 120, the eye-side surface 131 and the display-side surface 132 of the third lens 130, and the eye-side surface 141 and the display-side surface 142 of the fourth lens 140, are all defined according to the following aspherical curve formula:

[0101]

[0102] Z represents the depth of the 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);

[0103] R represents the radius of curvature of the lens surface;

[0104] Y represents the vertical distance between the point on the aspherical surface and the optical axis;

[0105] K is the cone constant;

[0106] a 2i is the 2i-th order aspheric coefficient.

[0107] Please refer to the detailed parameters of each aspheric surface. Fig.10 .

[0108] Figure 8 (a) is a schematic diagram showing the longitudinal spherical aberration of three representative wavelengths (486 nm, 587 nm, 656 nm) of this embodiment, wherein the horizontal axis is defined as the focal length and the vertical axis is defined as the field of view. Figure 8 (b) is a schematic diagram showing the astigmatism aberration in the sagittal direction of three representative wavelengths (486 nm, 587 nm, 656 nm) of this embodiment, where the horizontal axis is defined as the focal length and the vertical axis is defined as the half-eye viewing angle. Figure 8 (c) is a schematic diagram showing the astigmatism aberration in the meridian direction of three representative wavelengths (486 nm, 587 nm, 656 nm) of this embodiment, wherein the horizontal axis is defined as the focal length and the vertical axis is defined as the half-eye viewing angle. Figure 8 (d) shows the distortion aberration of this embodiment, where the horizontal axis is defined as a percentage and the vertical axis is defined as a half-eye viewing angle. The curves of each wavelength are very close, indicating that the off-axis light rays of different heights of each wavelength are concentrated near the imaging point. Figure 8 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.9mm. Therefore, this embodiment does significantly improve the longitudinal spherical aberration of different wavelengths. Figure 8 (b) The focal lengths of the three representative wavelengths within the entire field of view fall within the range of ±0.9 mm. Figure 8 (c) The focal lengths of the three representative wavelengths within the entire field of view fall within the range of ±0.9 mm. Figure 8 On the horizontal axis of (d), the distortion aberration is maintained within the range of ±35%.

[0109] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0110] ω is about 45 degrees, Fno is about 21.494, and SL is about 101.852 mm. In this embodiment, Fno is calculated based on the principle of photoreversibility, where the eye side is regarded as an object side, the display side is regarded as an image side, and the pupil P of the observer's eye is regarded as a pupil of incident light. Of course, other embodiments also use this basis to calculate Fno.

[0111] Please also refer to Figures 11 to 14 ,in Fig.11 FIG. 1 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a second embodiment of the present invention. Fig.12 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the second embodiment of the present invention. Fig.13 Detailed optical data of the eyepiece optical system according to the second embodiment of the present invention are shown. Fig.14 The aspheric surface data of each lens of the eyepiece optical system according to the second embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 2, for example, the eye side of the third lens is 231, the display side of the third lens is 232, and the reference numerals of other components are not repeated here.

[0112] like Fig.11 As shown, the eyepiece optical system 2 of this embodiment includes a first lens 210 , a second lens 220 , a third lens 230 and a fourth lens 240 in sequence from the eye side A1 to the display side A2 .

[0113] The concavo-convex configuration of the surfaces of the eye-side surfaces 211, 221, 231, 241 and the display side surfaces 212, 222, 242 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surface of the display side surface 232 is different from that of the first embodiment. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the second embodiment are also different from those of the first embodiment. Specifically, the difference is that the display side surface 232 of the third lens 230 includes a convex portion 2322 located in the vicinity of the circumference of the third lens 230.

[0114] In order to more clearly illustrate the drawings of this embodiment, the features of the concave-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 2 of this embodiment, please refer to Fig.13 .

[0115] from Fig.12 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.6mm. Fig.12(b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.6mm over the entire field of view. Fig.12 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.8mm over the entire field of view. Fig.12 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 2 is maintained within the range of ±40%.

[0116] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0117] In this embodiment, ω is about 45 degrees, Fno is about 21.890, and SL is about 132.258 mm. Compared with the first embodiment, the aberration of this embodiment is smaller and the manufacturing yield is higher.

[0118] Please also refer to Figures 15 to 18 ,in Fig.15 FIG. 1 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a third embodiment of the present invention. Fig.16 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the third embodiment of the present invention. Fig.17 Detailed optical data of the eyepiece optical system according to the third embodiment of the present invention are shown. Fig.18 The aspheric surface data of each lens of the eyepiece optical system according to the third embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 3, for example, the eye side of the third lens is 331, the display side of the third lens is 332, and the reference numerals of other components are not repeated here.

[0119] like Fig.15 As shown, the eyepiece optical system 3 of this embodiment includes a first lens 310 , a second lens 320 , a third lens 330 and a fourth lens 340 in sequence from the eye side A1 to the display side A2 .

[0120] The concavo-convex configuration of the surfaces of the eye side surfaces 311, 321, 331, 341 and the display side surfaces 312, 322, 342 is substantially similar to that of the first embodiment. However, the concavo-convex configuration of the surface of the display side surface 332 is different. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the third embodiment are also different from those of the first embodiment. Specifically, the difference is that the display side surface 332 of the third lens 30 includes a convex portion 3322 located in the vicinity of the circumference of the third lens 330.

[0121] In order to more clearly illustrate the drawings of this embodiment, the features of the concavo-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 3 of this embodiment, please refer to Fig.17 .

[0122] from Fig.16 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.5mm. Fig.16 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.8mm over the entire field of view. Fig.16 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.6mm over the entire field of view. Fig.16 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 3 is maintained within the range of ±40%.

[0123] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0124] In this embodiment, ω is about 45 degrees, Fno is about 17.054, and SL is about 98.782 mm. Compared with the first embodiment, the aberration, Fno value and SL value of this embodiment are smaller.

[0125] Please also refer to Figures 19 to 22 ,in Fig.19 FIG. 4 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a fourth embodiment of the present invention. Fig. 20 FIG. 4 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the fourth embodiment of the present invention. Fig.21 Detailed optical data of the eyepiece optical system according to the fourth embodiment of the present invention are shown. Fig. 22 The aspheric surface data of each lens of the eyepiece optical system according to the fourth embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 4, for example, the eye side of the third lens is 431, the display side of the third lens is 432, and the reference numerals of other components are not repeated here.

[0126] like Fig.18 As shown, the eyepiece optical system 4 of this embodiment includes an aperture 400 , a first lens 410 , a second lens 420 , a third lens 430 and a fourth lens 440 in sequence from the eye side A1 to the display side A2 .

[0127] The concavo-convex configuration of the surfaces of the eye-side surfaces 411, 421, 431 and the display side surfaces 412, 422, 432, 442 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surface of the eye-side surface 441 is different. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the fourth embodiment are also different from those of the first embodiment. In detail, the eye-side surface 441 of the fourth lens 440 includes a convex portion 4412 located in the vicinity of the circumference of the fourth lens 440.

[0128] In order to more clearly illustrate the drawings of this embodiment, the features of the concavo-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 4 of this embodiment, please refer to Fig.21 .

[0129] from Fig. 20 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.6mm. Fig. 20 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.7mm over the entire field of view. Fig. 20 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.6mm over the entire field of view. Fig. 20 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 4 is maintained within the range of ±40%.

[0130] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0131] In this embodiment, ω is about 45 degrees, Fno is about 16.698, and SL is about 93.387 mm. Compared with the first embodiment, the aberration, Fno value and SL value of this embodiment are smaller.

[0132] Please also refer to Figure 23 to Figure 26 ,in Fig.23 FIG. 4 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a fifth embodiment of the present invention. Fig.24 FIG. 5 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the fifth embodiment of the present invention. Fig.25 Detailed optical data of the eyepiece optical system according to the fifth embodiment of the present invention are shown. Fig.26 The aspheric surface data of each lens of the eyepiece optical system according to the fifth embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 5, for example, the eye side of the third lens is 531, the display side of the third lens is 532, and the reference numerals of other components are not repeated here.

[0133] like Fig.23 As shown, the eyepiece optical system 5 of this embodiment includes a first lens 510 , a second lens 520 , a third lens 530 and a fourth lens 540 in sequence from the eye side A1 to the display side A2 .

[0134] The concave-convex configuration of the surfaces of the eye side surfaces 511, 521, 531, 541 and the display side surfaces 512, 522, 532, 542 is substantially similar to that of the first embodiment, except that the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the fifth embodiment are also different from those of the first embodiment.

[0135] In order to more clearly illustrate the drawings of this embodiment, the features of the concave-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 5 of this embodiment, please refer to Fig.25 .

[0136] from Fig.24 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.9mm. Fig.24 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.9mm over the entire field of view. Fig.24 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.9mm over the entire field of view. Fig.24 On the horizontal axis of (d), the distortion aberration of the eyepiece optical system 5 is maintained within the range of ±30%.

[0137] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0138] In this embodiment, ω is about 45 degrees, Fno is about 22.505, and SL is about 104.980 mm. Compared with the first embodiment, the manufacturing yield of this embodiment is higher.

[0139] Please also refer to Figures 27 to 30 ,in Fig. 27 FIG. 4 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a sixth embodiment of the present invention. Fig.28 FIG. 6 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the sixth embodiment of the present invention. Fig.29 Detailed optical data of the eyepiece optical system according to the sixth embodiment of the present invention are shown. Fig.30 The aspheric surface data of each lens of the eyepiece optical system according to the sixth embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 6, for example, the eye side of the third lens is 631, the display side of the third lens is 632, and the reference numerals of other components are not repeated here.

[0140] like Fig. 27 As shown, the eyepiece optical system 6 of this embodiment includes a first lens 610 , a second lens 620 , a third lens 630 and a fourth lens 640 in sequence from the eye side A1 to the display side A2 .

[0141] The concavo-convex configuration of the surfaces of the eye-side surfaces 611, 621, 631, 641 and the display side surfaces 612, 622, 642 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surface of the display side surface 632 is different. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the sixth embodiment are also different from those of the first embodiment. In detail, the display side surface 632 of the third lens 630 includes a convex portion 6322 located in the vicinity of the circumference of the third lens 630.

[0142] In order to more clearly illustrate the drawings of this embodiment, the features of the concavo-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 6 of this embodiment, please refer to Fig.29 .

[0143] from Fig.28 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.5mm. Fig.28 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.8mm over the entire field of view. Fig.28 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.7mm over the entire field of view. Fig.28 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 6 is maintained within the range of ±40%.

[0144] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0145] In this embodiment, ω is about 45 degrees, Fno is about 20.156, and SL is about 120.340 mm. Compared with the first embodiment, the aberration and Fno values ​​of this embodiment are smaller.

[0146] Please also refer to Figure 31 to Figure 34 ,in Fig.31FIG. 1 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a seventh embodiment of the present invention. Fig.32 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the seventh embodiment of the present invention. Fig.33 Detailed optical data of the eyepiece optical system according to the seventh embodiment of the present invention are shown. Fig.34 The aspheric surface data of each lens of the eyepiece optical system according to the seventh embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 7, for example, the eye side of the third lens is 731, the display side of the third lens is 732, and the reference numerals of other components are not repeated here.

[0147] like Fig.30 As shown, the eyepiece optical system 7 of this embodiment includes a first lens 710, a second lens 720, a third lens 730 and a fourth lens 740 in sequence from the eye side A1 to the display side A2.

[0148] The concavo-convex configuration of the surfaces of the eye side surfaces 711, 721, 731, 741 and the display side surfaces 712, 722 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surfaces of the display side surfaces 732, 742 is different. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the seventh embodiment are also different from those of the first embodiment. In detail, the display side surface 732 of the third lens 730 includes a convex portion 7322 located in the vicinity of the circumference of the third lens 730, and the display side surface 742 of the fourth lens 740 includes a concave portion 7422 located in the vicinity of the circumference of the fourth lens 740.

[0149] In order to more clearly illustrate the drawings of this embodiment, the features of the concavo-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 7 of this embodiment, please refer to Fig.33 .

[0150] from Fig.32 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.6mm. Fig.32 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.7mm over the entire field of view. Fig.32 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.7mm over the entire field of view. Fig.32 On the horizontal axis of (d), the distortion aberration of the eyepiece optical system 7 is maintained within the range of ±40%.

[0151] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0152] In this embodiment, ω is about 45 degrees, Fno is about 19.419, and SL is about 103.787 mm. Compared with the first embodiment, the aberration and Fno values ​​of this embodiment are smaller.

[0153] Please also refer to Figures 35 to 38 ,in Fig.35 FIG. 4 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to an eighth embodiment of the present invention. Fig.36 FIG. 8 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the eighth embodiment of the present invention. Fig.37 Detailed optical data of the eyepiece optical system according to the eighth embodiment of the present invention are shown. Fig.38 The aspheric surface data of each lens of the eyepiece optical system according to the eighth embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 8, for example, the eye side of the third lens is 831, the display side of the third lens is 832, and the reference numerals of other components are not repeated here.

[0154] like Fig.35 As shown, the eyepiece optical system 8 of this embodiment includes a first lens 810, a second lens 820, a third lens 830 and a fourth lens 840 in sequence from the eye side A1 to the display side A2.

[0155] The concavo-convex configuration of the surfaces of the eye-side surfaces 811, 821, 831, 841 and the display side surfaces 812, 822, 842 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surface of the display side surface 832 is different. Furthermore, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the eighth embodiment are also different from those of the first embodiment. Specifically, the display side surface 832 of the third lens 830 includes a convex portion 8322 located in the vicinity of the circumference of the third lens 830.

[0156] In order to more clearly illustrate the drawings of this embodiment, the features of the concave-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 8 of this embodiment, please refer to Fig.37 .

[0157] from Fig.36 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.6mm. Fig.36 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.9mm over the entire field of view. Fig.36 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.7mm over the entire field of view. Fig.36 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 8 is maintained within the range of ±35%.

[0158] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0159] In this embodiment, ω is about 45 degrees, Fno is about 17.921, and SL is about 98.837 mm. Compared with the first embodiment, the aberration, Fno value and SL value of this embodiment are smaller.

[0160] Please also refer to Figures 39 to 42 ,in Fig.39 FIG. 4 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a ninth embodiment of the present invention. Fig.40 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the ninth embodiment of the present invention. Fig.41 Detailed optical data of the eyepiece optical system according to the ninth embodiment of the present invention are shown. Fig.42The aspheric surface data of each lens of the eyepiece optical system according to the ninth embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 9, for example, the eye side of the third lens is 931, the display side of the third lens is 932, and the reference numerals of other components are not repeated here.

[0161] like Fig.39 As shown, the eyepiece optical system 9 of this embodiment includes a first lens 910, a second lens 920, a third lens 930 and a fourth lens 940 in sequence from the eye side A1 to the display side A2.

[0162] The concavo-convex configuration of the surfaces of the eye-side surfaces 911, 921, 931 and the display side surfaces 912, 922, 932, 942 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surface of the eye-side surface 941 is different. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the ninth embodiment are also different from those of the first embodiment. In detail, the eye-side surface 941 of the fourth lens 940 includes a convex portion 9412 located in the vicinity of the circumference of the fourth lens 940.

[0163] In order to more clearly illustrate the drawings of this embodiment, the features of the concave-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 9 of this embodiment, please refer to Fig.41 .

[0164] from Fig.40 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.45mm. Fig.40 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.6mm over the entire field of view. Fig.40 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.5mm over the entire field of view. Fig.36 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 9 is maintained within the range of ±40%.

[0165] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0166] In this embodiment, ω is about 45 degrees, Fno is about 14.698, and SL is about 94.413 mm. Compared with the first embodiment, the aberration, Fno value and SL value of this embodiment are smaller.

[0167] Please also refer to Figure 43 to Figure 46 ,in Fig.43 FIG. 1 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to a tenth embodiment of the present invention. Fig.44 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the tenth embodiment of the present invention. Fig.45 Detailed optical data of the eyepiece optical system according to the tenth embodiment of the present invention are shown. Fig.46 The aspheric surface data of each lens of the eyepiece optical system according to the tenth embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the reference numerals used here begin with 10', for example, the eye side of the third lens is 10'31, and the display side of the third lens is 10'32, and the reference numerals of other components are not repeated here.

[0168] like Fig.43 As shown, the eyepiece optical system 10 ′ of this embodiment includes a first lens 10 ′10 , a second lens 10 ′20 , a third lens 10 ′30 and a fourth lens 10 ′40 in sequence from the eye side A1 to the display side A2 .

[0169] The concavo-convex configuration of the surfaces of the eye-side surfaces 10'11, 10'21, 10'31 and the display side surfaces 10'12, 10'22, 10'32, 10'42 is substantially similar to that of the first embodiment, except that the concavo-convex configuration of the surface of the eye-side surface 10'41 is different. In addition, the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the tenth embodiment are also different from those of the first embodiment. In detail, the eye-side surface 10'41 of the fourth lens 10'40 includes a convex portion 10'412 located in the vicinity of the circumference of the fourth lens 10'40.

[0170] In order to more clearly illustrate the drawings of this embodiment, the features of the concave-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 10' of this embodiment, please refer to Fig.45 .

[0171] from Fig.44 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.45mm. Fig.44 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.5mm over the entire field of view. Fig.44 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.5mm over the entire field of view. Fig.44 On the horizontal axis of (d), the distortion aberration of the eyepiece optical system 10' is maintained within the range of ±40%.

[0172] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0173] In this embodiment, ω is about 45 degrees, Fno is about 14.729, and SL is about 95.983 mm. Compared with the first embodiment, the aberration, Fno value and SL value of this embodiment are smaller.

[0174] Please also refer to Figures 47 to 50 ,in Fig.47 FIG. 1 is a schematic diagram showing a lens cross-sectional structure of an eyepiece optical system according to an eleventh embodiment of the present invention. Fig.48 FIG. 1 is a schematic diagram showing the longitudinal spherical aberration and various aberration diagrams of the eyepiece optical system according to the eleventh embodiment of the present invention. Fig.49 Detailed optical data of the eyepiece optical system according to the eleventh embodiment of the present invention are shown. Fig.50The aspheric surface data of each lens of the eyepiece optical system according to the eleventh embodiment of the present invention are shown. In this embodiment, similar reference numerals are used to indicate similar components as in the first embodiment, except that the beginning of the reference numerals used here is changed to 11', for example, the eye side of the third lens is 11'31, and the display side of the third lens is 11'32. The reference numerals of other components are not repeated here.

[0175] like Fig.47 As shown, the eyepiece optical system 11 ′ of this embodiment includes a first lens 11 ′10 , a second lens 11 ′20 , a third lens 11 ′30 and a fourth lens 11 ′40 in sequence from the eye side A1 to the display side A2 .

[0176] The concave-convex configuration of the surfaces of the eye side surfaces 11'11, 11'21, 11'31, 11'41 and the display side surfaces 11'12, 11'22, 11'32, 11'42 is substantially similar to that of the first embodiment, except that the optical parameters of the curvature radius, lens thickness, aspheric coefficient, and effective focal length of each lens surface of the eleventh embodiment are also different from those of the first embodiment.

[0177] In order to more clearly illustrate the drawings of this embodiment, the features of the concavo-convex configuration of the lens surface are only marked with the differences from the first embodiment, and the labels of the same parts are omitted. For the optical characteristics of each lens of the eyepiece optical system 11' of this embodiment, please refer to Fig.49 .

[0178] from Fig.48 The longitudinal deviation of each curve in (a) shows that the deviation of the imaging point of off-axis light at different heights is controlled within ±0.25mm. Fig.48 (b) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.3mm over the entire field of view. Fig.48 (c) The focal lengths of the three representative wavelengths (486nm, 587nm, 656nm) fall within the range of ±0.5mm over the entire field of view. Fig.48 In the horizontal axis of (d), the distortion aberration of the eyepiece optical system 11' is maintained within the range of ±40%.

[0179] For the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG, please refer to Fig.51 and Fig.52 .

[0180] In this embodiment, ω is about 45 degrees, Fno is about 14.700, and SL is about 91.151 mm. Compared with the first embodiment, the aberration, Fno value and SL value of this embodiment are smaller.

[0181] Fig.51 and Fig.52 By listing the values ​​of T1, G12, T2, G23, T3, G34, T4, G4D, EFL, TTL, TL, AAG, ALT, EPD, ER, DLD, TL / ER, T1 / (G23+G34), (T1+T3) / T4, ALT / AAG, EFL / G4D, TTL / ER, (T1+G12+T2) / (T3+G34+T4), (T3+T4) / G34, T2 / T1, T2 / (G23+G34), T1 / G34, and EFL / AAG of the above eleven embodiments, it can be seen that the eyepiece optical system of the present invention can indeed satisfy the aforementioned conditional equations (1) to (14).

[0182] Regarding the eyepiece optical system of the present invention, by designing the display side surface of the third lens to have a concave portion in the area near the optical axis and the eye side surface of the fourth lens to have a concave portion in the area near the optical axis, it is beneficial to improve the problems of small field of view angle and large chromatic aberration and distortion. If the display side of the first lens is selectively designed to have a convex portion in the area near the optical axis, or the refractive index of the second lens is a positive value, or the display side surface of the second lens is designed to have a convex portion in the area near the optical axis, the light can be focused to improve the overall imaging quality.

[0183] In order to shorten the overall length of the eyepiece optical system, the thickness of each lens and the air gap between lenses will be appropriately shortened. However, considering the difficulty of the lens assembly process and the need to balance the imaging quality, the lens thickness and the air gap between lenses need to be coordinated with each other. Therefore, the best configuration of the eyepiece optical system can be achieved under the numerical restrictions of the following conditional formula:

[0184] 0≦TL / ER≦8;

[0185] T1 / (G23+G34)≦2.5, the optimal range is 0.4≦T1 / (G23+G34)≦2.5;

[0186] (T1+T3) / T4≦4.5, the optimal range is 1.5≦(T1+T3) / T4≦4.5;

[0187] ALT / AAG ≤ 10, the optimal range is 2.0 ≤ ALT / AAG ≤ 10;

[0188] 2.4≦EFL / G4D, the optimal range is 2.4≦EFL / G4D≦9.0;

[0189] 0≦TTL / ER≦10;

[0190] (T1+G12+T2) / (T3+G34+T4)≦2.5, the preferred range is 0.5≦(T1+G12+T2) / (T3+G34+T4)≦2.5;

[0191] (T3+T4) / G34≦3.0, the optimal range is 0.8≦(T3+T4) / G34≦3.0;

[0192] 0.9≦T2 / T1, the optimal range is 0.9≦T2 / T1≦6.0;

[0193] T2 / (G23+G34)≦4.0, the optimal range is 0.5≦T2 / (G23+G34)≦4.0;

[0194] T1 / G34≦3.0, the optimal range is 0.4≦T1 / G34≦3.0;

[0195] 4.9≦EFL / AAG, the optimal range is 4.9≦EFL / AAG≦13.0.

[0196] The above description is based on a number of different embodiments of the present invention, wherein each feature may be implemented singly or in different combinations. Therefore, the disclosure of the embodiments of the present invention is a specific example of the principles of the present invention, and the present invention should not be limited to the disclosed embodiments. Furthermore, the above description and the accompanying drawings are only for the purpose of illustrating the present invention and are not intended to be limiting. Other variations or combinations of components are possible without violating the spirit and scope of the present invention.

Claims

1. An eyepiece optical system, adapted to allow an imaging light of a display screen to enter an eye of an observer through the eyepiece optical system to form an image, the direction toward the eye being the eye side, and the direction toward the display screen being the display side, wherein the eyepiece optical system comprises a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side, and the first lens, the second lens, the third lens, and the fourth lens each comprise 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, characterized in that: The first lens has a positive refractive power, the display side surface of the first lens includes a convex portion located in a region near the optical axis, and the eye side surface of the first lens includes a concave portion located in a region near the optical axis; The second lens has a positive refractive power, the eye side surface of the second lens includes a convex portion located in a region near the optical axis, and the display side surface of the second lens includes a convex portion located in a region near the optical axis; The third lens has a negative refractive power, the eye side surface of the third lens includes a concave portion located in a region near the optical axis, and the display side surface of the third lens includes a concave portion located in a region near the optical axis; The fourth lens has a negative refractive power, the eye side surface of the fourth lens includes a concave portion located in a region near the optical axis, and the display side surface of the fourth lens includes a concave portion located in a region near the optical axis; The eyepiece optical system has only the above four lenses; and The eyepiece optical system meets the following conditions: EFL / G4D≧2.4, Wherein, EFL represents the effective focal length of the eyepiece optical system, and G4D represents the distance from the display side of the fourth lens to the display screen on the optical axis.

2. An eyepiece optical system, adapted to allow an imaging light of a display screen to enter an eye of an observer through the eyepiece optical system to form an image, the direction toward the eye being the eye side, and the direction toward the display screen being the display side, wherein the eyepiece optical system comprises a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side, and the first lens, the second lens, the third lens, and the fourth lens each comprise 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, characterized in that: The first lens has a positive refractive power, the display side surface of the first lens includes a convex portion located in a region near the circumference and a convex portion located in a region near the optical axis, and the eye side surface of the first lens includes a concave portion located in a region near the optical axis; The second lens has a positive refractive power, the eye side surface of the second lens includes a convex portion located in a region near the optical axis, and the display side surface of the second lens includes a convex portion located in a region near the optical axis; The third lens has a negative refractive power, the eye side surface of the third lens includes a concave portion located in a region near the optical axis, and the display side surface of the third lens includes a concave portion located in a region near the optical axis; The fourth lens has a negative refractive power, the eye side surface of the fourth lens includes a concave portion located in a region near the optical axis, and the display side surface of the fourth lens includes a concave portion located in a region near the optical axis; The eyepiece optical system has only the above four lenses; and The eyepiece optical system meets the following conditions: EFL / G4D≧2.4, Wherein, EFL represents the effective focal length of the eyepiece optical system, and G4D represents the distance from the display side of the fourth lens to the display screen on the optical axis.

3. The eyepiece optical system according to claim 1 or 2, characterized in that: Wherein TL represents the distance from the eye side of the first lens to the display side of the fourth lens on the optical axis, ER represents the distance from the pupil of the observer to the eye side of the first lens on the optical axis, and TL and ER satisfy the conditional expression of 0≦TL / ER≦8.

4. The eyepiece optical system according to claim 1 or 2, characterized in that: Wherein TTL represents the distance from the eye side of the first lens to the display screen on the optical axis, ER represents the distance from the pupil of the observer to the eye side of the first lens on the optical axis, and TTL and ER satisfy the conditional expression of 0≦TTL / ER≦10.

5. An eyepiece optical system, adapted to allow an imaging light of a display screen to enter an eye of an observer through the eyepiece optical system to form an image, the direction toward the eye being the eye side, and the direction toward the display screen being the display side, wherein the eyepiece optical system comprises a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side, and the first lens, the second lens, the third lens, and the fourth lens each comprise 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, characterized in that: The first lens has a positive refractive power, the display side surface of the first lens includes a convex portion located in a region near the circumference and a convex portion located in a region near the optical axis, and the eye side surface of the first lens includes a concave portion located in a region near the optical axis; The second lens has a positive refractive power, the eye side surface of the second lens includes a convex portion located in a region near the optical axis, and the display side surface of the second lens includes a convex portion located in a region near the optical axis; The third lens has a negative refractive power, the eye side surface of the third lens includes a concave portion located in a region near the optical axis, and the display side surface of the third lens includes a concave portion located in a region near the optical axis; The fourth lens has a negative refractive power, the eye side surface of the fourth lens includes a concave portion located in a region near the optical axis, and the display side surface of the fourth lens includes a concave portion located in a region near the optical axis; The eyepiece optical system has only the above four lenses; and The eyepiece optical system meets the following conditions: EFL / G4D≧2.4 and 0≦TL / ER≦8, Among them, EFL represents the effective focal length of the eyepiece optical system, G4D represents the distance from the display side of the fourth lens to the display screen on the optical axis, TL represents the distance from the eyepiece side of the first lens to the display side of the fourth lens on the optical axis, and ER represents the distance from the observer's pupil to the eyepiece side of the first lens on the optical axis.

6. An eyepiece optical system, adapted to allow an imaging light of a display screen to enter an eye of an observer through the eyepiece optical system to form an image, the direction toward the eye being the eye side, and the direction toward the display screen being the display side, wherein the eyepiece optical system comprises a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from the eye side to the display side, and the first lens, the second lens, the third lens, and the fourth lens each comprise 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, characterized in that: The first lens has a positive refractive power, the display side surface of the first lens includes a convex portion located in a region near the optical axis, and the eye side surface of the first lens includes a concave portion located in a region near the optical axis; The second lens has a positive refractive power, the eye side of the second lens includes a convex portion located in a region near the circumference and a convex portion located in a region near the optical axis, and the display side of the second lens includes a convex portion located in a region near the optical axis; The third lens has a negative refractive power, the eye side of the third lens includes a concave portion located in a region near the optical axis, and the display side of the third lens includes a concave portion located in a region near the optical axis; The fourth lens has a negative refractive power; the eye side of the fourth lens includes a concave portion located in a region near the optical axis, and the display side of the fourth lens includes a concave portion located in a region near the optical axis; The eyepiece optical system has only the above four lenses; and The eyepiece optical system meets the following conditions: EFL / G4D≧2.4 and 0≦TL / ER≦8, Among them, EFL represents the effective focal length of the eyepiece optical system, G4D represents the distance from the display side of the fourth lens to the display screen on the optical axis, TL represents the distance from the eyepiece side of the first lens to the display side of the fourth lens on the optical axis, and ER represents the distance from the observer's pupil to the eyepiece side of the first lens on the optical axis.

7. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein ALT represents the sum of the center thicknesses of the four lenses from the first lens to the fourth lens on the optical axis, AAG represents the sum of the three air gap widths of the first lens to the fourth lens on the optical axis, and ALT and AAG satisfy the conditional expression of ALT / AAG≦10.

8. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: The Abbe number of the first lens is the same as the Abbe number of the second lens.

9. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that:Wherein T1 represents the center thickness of the first lens on the optical axis, G12 represents the width of the air gap between the first lens and the second lens on the optical axis, T2 represents the center thickness of the second lens on the optical axis, T3 represents the center thickness of the third lens on the optical axis, G34 represents the width of the air gap between the third lens and the fourth lens on the optical axis, T4 represents the center thickness of the fourth lens on the optical axis, and T1, T2, T3, T4, G12 and G34 satisfy the conditional expression of (T1+G12+T2) / (T3+G34+T4)≦2.

5.

10. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein T3 represents the center thickness of the third lens on the optical axis, T4 represents the center thickness of the fourth lens on the optical axis, G34 represents the width of the air gap between the third lens and the fourth lens on the optical axis, and T3, T4 and G34 satisfy the conditional expression of (T3+T4) / G34≦3.

0.

11. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: The center thickness of the second lens on the optical axis is greater than the center thickness of the third lens on the optical axis.

12. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein T1 represents the center thickness of the first lens on the optical axis, T2 represents the center thickness of the second lens on the optical axis, and T1 and T2 satisfy the conditional expression of T2 / T1≧0.

9.

13. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein T2 represents the center thickness of the second lens on the optical axis, G23 represents the width of the air gap between the second lens and the third lens on the optical axis, G34 represents the width of the air gap between the third lens and the fourth lens on the optical axis, and T2, G23 and G34 satisfy the conditional expression of T2 / (G23+G34)≦4.

0.

14. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein T1 represents the center thickness of the first lens on the optical axis, G34 represents the width of the air gap between the third lens and the fourth lens on the optical axis, and T1 and G34 satisfy the conditional expression of T1 / G34≦3.

0.

15. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: AAG represents the sum of the widths of three air gaps of the first lens to the fourth lens on the optical axis, and EFL and AAG satisfy the conditional expression of EFL / AAG≧4.

9.

16. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: The center thickness of the second lens on the optical axis is greater than the center thickness of the first lens on the optical axis.

17. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein T1 represents the center thickness of the first lens on the optical axis, G23 represents the width of the air gap between the second lens and the third lens on the optical axis, G34 represents the width of the air gap between the third lens and the fourth lens on the optical axis, and T1, G23 and G34 satisfy the conditional expression of T1 / (G23+G34)≦2.

5.

18. The eyepiece optical system according to claim 1, 2, 5 or 6, characterized in that: Wherein T1 represents the center thickness of the first lens on the optical axis, T3 represents the center thickness of the third lens on the optical axis, T4 represents the center thickness of the fourth lens on the optical axis, and T1, T3 and T4 satisfy the conditional expression of (T1+T3) / T4≦4.5.

Images