TWI628464B - Eye relief adjustable eyepiece system - Google Patents

Abstract

An adjustable eye distance eyepiece system includes an aperture, a first lens having a refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, and a positive refractive power in order along the optical axis from the object side to the image side. Fourth lens. The first lens to the fourth lens are adapted to move toward the object side or the image side together according to the user's proper eye distance. Each of the first to fourth lenses includes an object side surface and an image side surface. The suitable eye distance adjustable eyepiece system satisfies: 0 <| R5 / f3 | <3.5, where R5 is the curvature radius of the object side of the third lens, and f3 is the focal length of the third lens.

Description

Eye distance adjustable eyepiece system

The present invention relates to an optical system, and in particular, to an adjustable eyepiece system with a suitable eye distance.

With the rapid development of technology, the application scope of optical lens groups is not limited to telescopes and microscopes, but also widely used in electronic products such as electronic view finder and head-mounted display. The head-mounted display (HMD) mainly transmits the content displayed by the display to the human eye through the optical lens group, so that the human eye perceives an enlarged virtual image.

Current head-mounted displays include light-transmissive head-mounted displays and non-light-transmissive head-mounted displays. The light-transmitting head-mounted display allows the human eye to receive the content displayed by the display and the external image. The non-light-transmitting head-mounted display only allows the human eye to receive the content displayed on the display, allowing users to fully immerse themselves in the virtual world. Therefore, non-light-transmitting head-mounted displays need to have good imaging quality and a large field of view (FOV), so that users will not feel uncomfortable using the head-mounted display for a long time. In the conventional technology, the suitable eye distance of the head-mounted display (that is, the maximum distance between the eye and the optical lens group when the user can clearly see the image) is generally designed as a fixed value (15 mm). However, in practical applications, the actual suitable eye distance may be different from the above design value because the user has nearsightedness or farsightedness. Therefore, there is a need for a display system with a large field of view angle, good imaging quality, and adjustable eye distance.

The present invention provides an adjustable eye distance adjustable eyepiece system, which has a large field angle, good imaging quality, and adjustable adjustable eye distance.

An adjustable eye distance adjustable eyepiece system of the present invention includes an aperture, a first lens having a refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, and an optical axis in order from the object side to the image side. Fourth lens with positive refractive power. The first lens to the fourth lens are adapted to move toward the object side or the image side together according to the user's proper eye distance. Each of the first lens to the fourth lens includes an object side facing the object side and passing imaging rays and an image side facing the image side and passing imaging rays. The suitable eye distance adjustable eyepiece system satisfies: 0 <| R5 / f3 | <3.5, where R5 is the curvature radius of the object side of the third lens, and f3 is the focal length of the third lens.

In an embodiment of the present invention, the adjustable eye distance adjustable eyepiece system also satisfies: 0.7 <| Φ3 / (Φ1 + Φ2) | <4.5, where Φ1 is the reciprocal of the focal length of the first lens and Φ2 is the reciprocal of the second lens. The inverse of the focal length, and Φ3 is the inverse of the focal length of the third lens.

In an embodiment of the present invention, the adjustable eye distance adjustable eyepiece system also satisfies: | V2-V3 |> 20, where V2 is the dispersion coefficient of the second lens and V3 is the dispersion coefficient of the third lens.

In an embodiment of the present invention, the eye-adjustable eyepiece system further satisfies: 1.5 <TTL / D2 <5.5, where TTL is the distance from the aperture to the display on the optical axis, and D2 is the object from the aperture to the first lens. The distance of the side on the optical axis.

In an embodiment of the present invention, the object side surface of the second lens is convex in the vicinity of the optical axis. At least one of the object side surface and the image side surface of the second lens is an aspheric surface. The object-side surface of the third lens is a concave surface in the vicinity of the optical axis. At least one of the object side surface and the image side surface of the third lens is an aspheric surface. The object-side surface of the fourth lens is convex in the vicinity of the optical axis. At least one of the object side surface and the image side surface of the fourth lens is an aspheric surface.

In an embodiment of the present invention, the refractive power of the first lens is positive. The object-side surface of the first lens is convex in the vicinity of the optical axis. The image side surface of the second lens is convex in the vicinity of the optical axis. The image side surface of the fourth lens is concave in the vicinity of the optical axis.

In an embodiment of the present invention, the refractive power of the first lens is negative. The image side surface of the first lens is concave in the vicinity of the optical axis, and the image side surface of the third lens is convex in the vicinity of the optical axis.

In an embodiment of the present invention, a region of the object side surface of the first lens near the optical axis is concave. The image side surface of the second lens is convex in the vicinity of the optical axis. The image side surface of the fourth lens is convex in the vicinity of the optical axis.

In an embodiment of the present invention, a region of the object side surface of the first lens near the optical axis is convex. The image side surface of the second lens is concave in the vicinity of the optical axis. The image side surface of the fourth lens is concave in the vicinity of the optical axis.

In an embodiment of the present invention, the object side and the image side of each of the second lens, the third lens, and the fourth lens are aspheric surfaces.

Based on the above, the beneficial effect of the adjustable eye distance adjustable eyepiece system of the embodiment of the present invention is: by designing and arranging the concave and convex shape of the object side or the image side of the lens, the adjustable eye distance adjustable eyepiece system has a large vision Field angle, good imaging quality, and adjustable eye distance.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

In this specification, the "eye distance" refers to the distance between the aperture (or the user's eye) and the first lens of the eye distance adjustable eyepiece system on the optical axis. The eye-adjustable eyepiece system can be applied to a head-mounted display, and the head-mounted display can have two eye-adjustable eyepiece systems set corresponding to the left and right eyes of a user. The two eye-adjustable eyepiece systems can be adjusted (manually or automatically) according to the vision of the left and right eyes.

For non-light-transmitting head-mounted displays, two eye-adjustable eyepiece systems can be set up in front of the left and right eyes of the user, and one eye-adjustable eyepiece system can be set in front of each A monitor, or two eye-adjustable eyepiece systems can share a single monitor. Because the display is not transparent and the display is set in front of the user's line of sight, the user cannot see the external image and can be completely immersed in the virtual world.

As for the transparent head-mounted display, the display and the eye-adjustable eyepiece system can be set around the user's eyes without blocking the user's line of sight, and pass through the beam splitter and light guide element ( light guide element) transmits the light beam from the display through the eye-adjustable eyepiece system to the eyes of the user. Since the light-shielding element (such as the display) in the head-mounted display does not block the user's line of sight, the user can receive the content displayed by the display and the external image.

In this specification, "the lens has positive refractive power (or negative refractive power)" means that the refractive power of the lens on the optical axis calculated by Gaussian optical theory is positive (or negative). In the eye-adjustable adjustable eyepiece system, each lens is symmetrical with each other radially with the optical axis as a symmetry axis. Each lens has an object side and an image side opposite the object side. The side of the object and the side of the image are defined as the range through which the imaging light passes. The imaging light includes the chief ray and the marginal ray. The object side (or image side) has a nearby area of the optical axis and an edge area that connects and surrounds the nearby area of the optical axis. The area near the optical axis is a region on the optical axis through which the imaging light passes. The edge area is an area that is passed by the edge light.

"A surface (object side or image side) of the lens is convex or concave in the vicinity of the optical axis" is determined by the positive and negative values of the R value (referring to the radius of curvature of the paraxial axis) of the surface in the vicinity of the optical axis. For the object side, when the R value is positive, it is determined that the object side is near the optical axis as a convex surface, that is, the object side has a convex portion near the optical axis. When the R value is negative, It is determined that the area of the object side surface in the vicinity of the optical axis is concave, that is, the area of the object side surface has a concave portion in the vicinity of the optical axis. For the image side, when the R value is positive, it is determined that the area of the image side near the optical axis is concave, that is, the image side has a concave surface near the optical axis; when the R value is negative, it is determined that the image side is at The area near the optical axis is convex, that is, the image side has a convex surface in the area near the optical axis.

One surface (object side or image side) of the lens may have more than one convex portion, more than one concave portion, or a combination of the two. When the surface has a convex surface and a concave surface, the surface has a inflection point. The inflection point is the transition point between the convex and concave parts. That is, the surface changes from convex to concave, or from concave to convex at the inflection point. On the other hand, when the surface has only a convex surface portion or only a concave surface portion, the surface has no inflection point.

1A and FIG. 1B are schematic diagrams when the diopters of an adjustable eye distance adjustable eyepiece system according to the first embodiment of the present invention are + 2D and -8D, respectively. Referring to FIG. 1A and FIG. 1B, the eye-adjustable eyepiece system 10 according to the first embodiment of the present invention includes an aperture A, a first lens 1, a second lens 2, and an optical axis I in order from the object side to the image side. Third lens 3 and fourth lens 4. The object side refers to the side of the user's eyes, and the image side refers to the side of the display 9. The light beam emitted by the display 9 will sequentially pass through the fourth lens 4, the third lens 3, the second lens 2, the first lens 1, and the aperture A, and then be received by the eyes of the user located at the aperture A.

In this embodiment, the first lens 1 to the fourth lens 4 are separated from each other without forming a cemented lens. In addition, in the eye-adjustable eyepiece system 10, only the first lens 1 to the fourth lens 4 have refractive power, that is, there are only four lenses having refractive power.

The first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 each include an object side surface 11, 21, 31, 41 that faces the object side and passes imaging rays, and an image that faces the image side and passes imaging rays. Sides 12, 22, 32, 42.

The first lens 1 has a positive refractive power. The object-side surface 11 of the first lens 1 is convex in the vicinity of the optical axis I, and the image-side 12 of the first lens 1 is convex in the vicinity of the optical axis I. The second lens 2 has a positive refractive power. The object-side surface 21 of the second lens 2 is convex in the vicinity of the optical axis I, and the image-side 22 of the second lens 2 is convex in the vicinity of the optical axis I. The third lens 3 has a negative refractive power. The object-side surface 31 of the third lens 3 is concave in the vicinity of the optical axis I, and the image-side 32 of the third lens 3 is concave in the vicinity of the optical axis I. The fourth lens 4 has a positive refractive power. The object-side surface 41 of the fourth lens 4 is convex in the vicinity of the optical axis I, and the image-side 42 of the fourth lens 4 is concave in the vicinity of the optical axis I. In another embodiment, the image-side surface 32 of the third lens 3 may be convex in the vicinity of the optical axis I. Correspondingly, the image side surface 12 of the first lens 1 may be flat or concave in the vicinity of the optical axis I, and the object side surface 21 of the second lens 2 may be flat or concave in the vicinity of the optical axis I.

The first lens 1 has a refractive power, which is suitable for controlling a field angle of the adjustable eye distance system 10. The second lens 2 has a positive refractive power, which is helpful to help the first lens 1 receive more light beams and correct spherical aberration. The third lens 3 has a negative refractive power, which is suitable for compensating chromatic aberration. The second lens 2 with a positive refractive power and the third lens 3 with a negative refractive power can reduce the Petzval sum of the eye-adjustable eyepiece system 10 and effectively correct image field curvature. The fourth lens 4 has a positive refractive power, and at least one of the object-side surface 41 and the image-side surface 42 is aspheric, which is advantageous for adjusting distortion.

The first to fourth lenses 1 to 4 are adapted to move together toward the object side or the image side depending on the user's appropriate eye distance. For example, when the eye (one of the users) at the aperture A has nearsightedness, the first lens 1 to the fourth lens 4 can be moved together toward the image side (ie, toward the display 9), and when the aperture is located at the aperture 9 When the eye at A has hyperopia, the first lens 1 to the fourth lens 4 can be moved toward the object side (that is, toward the aperture A). It should be noted that the first lens 1 to the fourth lens 4 belong to the same lens group, and the distance between the two lenses of the four lenses on the optical axis I is a constant value. When there is a need to adjust the eye distance, the four lenses will move together instead of individually.

By adjusting the positions of the four lenses between the aperture A and the display 9, the proper eye distance can be adjusted without changing the distance between the aperture A and the display 9, so that the adjustable eye distance adjustable eyepiece system 10 has a fixed Size and streamlined assembly (no need to set up a mechanism to move the display 9). In addition, since the adjustable eye distance adjustable eyepiece system 10 can adjust the appropriate eye distance according to the degree of nearsightedness or farsightedness of the user's eyes, so that the user can clearly see the image displayed on the display 9 under the condition of the naked eye. When the wearable display uses the adjustable eye distance eyepiece system 10, the user may not need to additionally wear a vision correction device (such as glasses). In this way, the wearing weight of the user can be reduced and the burden of long-term use can be reduced.

In order to meet the demand for weight reduction, the first lens 1 to the fourth lens 4 may be made of plastic material. However, at least one of the first lens 1 to the fourth lens 4 may be made of a glass material. For example, the first lens 1 of the first embodiment may be made of a glass material.

The detailed optical parameters of the first embodiment are shown in Tables 1 and 2. In Tables 1 and 2, "D1" represents the distance from the enlarged virtual image seen by the eye to the aperture A on the optical axis I. When D1 is positive, it means that the aperture A is located between the enlarged virtual image and the image side (that is, the aperture A is closer to the image side than the enlarged virtual image). When D1 is negative, it means that the enlarged virtual image is located between the aperture A and the image side (that is, the enlarged virtual image is closer to the image side than the aperture A). “D2” represents the distance from the aperture A to the object side surface 11 of the first lens 1 on the optical axis I, that is, the proper eye distance. “D10” represents the distance from the image side 42 of the fourth lens 4 to the display 9 on the optical axis I. In Table 2, "diopter (+ 2D)" indicates 200 degrees of hyperopia, and "diopter (-8D)" indicates 800 degrees of myopia. As can be seen from Table 2, in order to enable the eye to clearly see the enlarged virtual image, in the case of hyperopia, the lens group (including the first lens 1 to the fourth lens 4) must be moved toward the aperture (that is, shorten D2 and increase D10); In the case of nearsightedness, the lens group must be moved toward the display 9 (ie, increase D2 and shorten D10).

In Table 1, the distance (mm) corresponding to the object side surface 11 of the first lens 1 is 3.1019, which represents the distance on the optical axis I from the object side surface 11 of the first lens 1 to the image side surface 12 of the first lens 1 (that is, The thickness of the first lens 1 on the optical axis I) is 3.1019 mm. Similarly, the distance (mm) corresponding to the image side 12 of the first lens 1 is 0.04, which means that the distance on the optical axis I from the image side 12 of the first lens 1 to the object side 21 of the second lens 2 is 0.04 mm. Other fields of distance (mm) can be deduced by analogy, and will not be repeated here.         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> First embodiment </ td> </ tr> <tr> <td> Effective focal length = 15.6 mm, Half Field Of View (HFOV) = 25 degrees </ td> </ tr> <tr> <td> </ td> <td> surface </ td> <td> radius of curvature ( mm) </ td> <td> distance (mm) </ td> <td> refractive index </ td> <td> dispersion coefficient </ td> </ tr> <tr> <td> enlarged virtual image </ td > <td> </ td> <td> infinitely large </ td> <td> D1 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Aperture A </ td> <td> </ td> <td> Infinity </ td> <td> D2 (variable) </ td> <td> </ td> <td> </ td > </ tr> <tr> <td> First lens 1 </ td> <td> Object side 11 </ td> <td> 74.1996 </ td> <td> 3.1019 </ td> <td> 1.75 < / td> <td> 52.5 </ td> </ tr> <tr> <td> Like side 12 </ td> <td> -21.1889 </ td> <td> 0.04 </ td> </ tr> < tr> <td> Second lens 2 </ td> <td> Object side 21 </ td> <td> 12.1201 </ td> <td> 6.7392 </ td> <td> 1.53 </ td> <td> 56.2 </ td> </ tr> <tr> <td> Like side 22 </ td> <td> -13.0281 </ td> <td> 0.9063 </ td> </ tr> <tr> <td> Triple lens 3 </ td> <td> Object side 31 </ td> <td> -3.2611 </ td> <td> 1.6703 </ td> <td> 1.58 </ td> <td> 30.1 </ td> </ tr> <tr> <td> Like side 32 </ td> <td> 12.6649 </ td> <td> 0.7192 </ td> </ tr> <tr> <td> Fourth Lens 4 </ td> <td> Object side 41 </ td> <td> 3.59337 </ td> <td> 5.1034 </ td> <td> 1.53 </ td> <td> 56.6 </ td> </ td> tr> <tr> <td> Like side 42 </ td> <td> 10.609 </ td> <td> D10 (variable) </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Variables </ td> <td> D1 (mm) </ td> <td> D2 ( mm) </ td> <td> D10 (mm) </ td> </ tr> <tr> <td> Diopter (+ 2D) </ td> <td> 500 </ td> <td> 13.7 </ td> <td> 4.3 </ td> </ tr> <tr> <td> Diopter (-8D) </ td> <td> -125 </ td> <td> 16.5 </ td> <td> 1.5 </ td> </ tr> </ TBODY> </ TABLE>       

In this embodiment, the object side surface 11 and the image side surface 12 of the first lens 1 are spherical surfaces. In addition, a total of six surfaces including the object side surface 12 and the image side surface 22 of the second lens 2, the object side surface 31 and the image side surface 32 of the third lens 3, and the object side surface 41 and the image side surface 42 of the fourth lens 4 are aspheric surfaces. The sphere is defined by formula (1): (1)

In formula (1), Y is the distance between the point on the aspheric curve and the optical axis I. Z is the depth of the aspheric surface. R is the radius of curvature of the lens surface at the near optical axis I. K is a conic constant. Is the aspheric coefficient of the i-th order.

Table 3 shows the aspheric coefficients of the object side surface 21 of the second lens 2 to the image side surface 42 of the fourth lens 4 in the formula (1). Among them, the field number 21 in Table 3 indicates that it is the aspheric coefficient of the object side surface 21 of the second lens 2, and other fields can be deduced by analogy. Since the second-order aspherical coefficient A ₂ and the fourteenth-order aspherical coefficient A _{14 of these} six surfaces are both 0, the illustration is omitted. <TABLE border = "1" borderColor = "# 000000" width = "85%"><TBODY><tr><td> surface </ td><td> K </ td><td> A <sub> 4 </ sub></td><td> A <sub> 6 </ sub></td><td> A <sub> 8 </ sub></td><td> A <sub> 10 </ sub></td><td> A <sub> 12 </ sub></td></tr><tr><td> 21 </ td><td> -1.022 </ td><td>- 5.685E-05 </ td><td> 5.830E-07 </ td><td> -9.529E-09 </ td><td> 7.211E-11 </ td><td> -1.695E-13 </ td></tr><tr><td> 22 </ td><td> 0.3347 </ td><td> -7.191E-05 </ td><td> 2.542E-06 </ td><td> -2.810E-09 </ td><td> -1.026E-10 </ td><td> 2.569E-12 </ td></tr><tr><td> 31 </ td><td> -5.409 </ td><td> 5.940E-05 </ td><td> -3.379E-06 </ td><td> 1.471E-08 </ td><td> 3.014E-10 </ td><td> -6.903E-13 </ td></tr><tr><td> 32 </ td><td> -0.01428 </ td><td> 5.777E-04 </ td ><td> -3.230E-06 </ td><td> -8.162E-08 </ td><td> -1.107E-10 </ td><td> 1.435E-11 </ td></tr><tr><td> 41 </ td><td> -6.055 </ td><td> 2.594E-04 </ td><td> -4.390E-06 </ td><td> 6.366E -08 </ td><td> -3.130E-09 </ td><td> 3.640E-11 </ td></tr><tr><td> 42 </ td><td> -124.4 < / td><td> 8.860E-04 </ td><td> -1.319E-05 </ td><td> -9.810E-08 </ td><td> 1.698E-09 </ td><td> 1.923E-11 </ td></tr></TBODY></TABLE>

In view of the unpredictability of the optical system design, under the framework of the present invention, at least one of the following conditional expressions can better shorten the system's length, increase the field of view angle, improve the imaging quality, or manufacture Yield increases to improve the disadvantages of the prior art.

High resolution can be achieved by satisfying 0.7 <| Φ3 / (Φ1 + Φ2) | <4.5, where Φ1 is the inverse of the focal length of the first lens 1, Φ2 is the inverse of the focal length of the second lens 2, and Φ3 is the third The inverse of the focal length of the lens 3. When the upper limit of the above conditional expression is biased, the combined refractive power of the first lens 1 and the second lens 2 is too small, which causes the length (TTL) of the system to be too long. When the lower limit of the above conditional expression is biased, the refractive power of the first lens 1 and the second lens 2 are too large, which makes it difficult to correct aberrations, especially coma.

By satisfying 0 <| R5 / f3 | <3.5, the correction of low-order aberrations is favorable, where R5 is the radius of curvature of the object side surface 31 of the third lens 3, and f3 is the focal length of the third lens 3.

By satisfying | V2-V3 |> 20, the ability to correct chromatic aberration can be improved, where V2 is the dispersion coefficient of the second lens 2 and V3 is the dispersion coefficient of the third lens 3. Dispersion coefficient is also called Abbe number

By satisfying 1.5 <TTL / D2 <5.5, images with different diopters can be clearly analyzed, where TTL is the distance from the aperture A to the display 9 on the optical axis I (that is, the length of the system).

The relationship between the important parameters in the adjustable eye distance adjustable eyepiece system 10 of the first embodiment is shown in Table 4. In Table 4, "D2 (+ 2D)" indicates the distance from the aperture A to the object side 11 of the first lens 1 on the optical axis I when the refractive power is + 2D, that is, the proper eye distance when the refractive power is + 2D. “D2 (-8D)” indicates the distance from the aperture A to the object side 11 of the first lens 1 on the optical axis I when the diopter is -8D, that is, the proper eye distance when the diopter is -8D. Similarly, "TTL / D2 (+ 2D)" and "TTL / D2 (-8D)" respectively represent TTL / D2 when the diopters are + 2D and -8D.         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Φ <sub> 1 </ sub> </ td> <td> 0.045166 </ td> </ tr> <tr> <td> Φ <sub> 2 </ sub> </ td> <td> 0.076731 </ td> </ tr> <tr> <td> Φ <sub> 3 </ sub> </ td> <td> -0.23451 </ td> </ tr> <tr> <td> | Φ <sub> 3 </ sub> / (Φ <sub> 1 </ sub> + Φ <sub> 2 </ sub>) | </ td> <td> -1.9238 </ td> </ tr> <tr> <td> f3 </ td> <td> -4.2643 </ td> </ tr> <tr> <td> | R5 / f3 | </ td> <td> 0.652159 </ td> </ tr> <tr> <td> | V2-V3 | </ td> <td> 26.134 </ td> </ tr > <tr> <td> TTL </ td> <td> 36.09 </ td> </ tr> <tr> <td> D2 (+ 2D) </ td> <td> 13.7 </ td> </ tr > <tr> <td> D2 (-8D) </ td> <td> 16.5 </ td> </ tr> <tr> <td> TTL / D2 (+ 2D) </ td> <td> 2.69 < / td> </ tr> <tr> <td> TTL / D2 (-8D) </ td> <td> 2.23 </ td> </ tr> </ TBODY> </ TABLE>       

2 and 3 are field curvature aberration diagrams when the diopters of the adjustable eyepiece system of the first embodiment are + 2D and -8D, respectively, which illustrate the image of the sagittal direction of the first embodiment Astigmatic aberration and astigmatic aberration in the tangential direction. FIG. 4 and FIG. 5 are distortion aberration diagrams when the refractive power of the adjustable eyepiece system of the first embodiment is + 2D and -8D. FIG. 6A to FIG. 6F and FIG. 7A to FIG. 7F are transverse beam fan diagrams when the diopter of the adjustable eye distance system of the first embodiment is + 2D and -8D, respectively. The graphs shown in FIG. 2 to FIG. 7F are all within the standard range, so it can be verified that the adjustable eye distance adjustable eyepiece system 10 of the first embodiment has good imaging quality.

From the above, compared with the conventional display, the adjustable eye distance adjustable eyepiece system 10 of the first embodiment can have a large field angle, good imaging quality, and adjustable adjustable eye distance.

8A and FIG. 8B are schematic diagrams when the diopters of an adjustable eye distance adjustable eyepiece system according to the second embodiment of the present invention are + 2D and -8D, respectively. 8A and 8B, a second embodiment of the adjustable eye distance adjustable eyepiece system 10 of the present invention is substantially similar to the first embodiment. The main difference is that the optical data, aspherical coefficients, and parameters between these lenses (first lens 1, second lens 2, third lens 3, and fourth lens 4) are more or less different. In addition, the first lens 1 has a negative refractive power. The object-side surface 11 of the first lens 1 is concave in the vicinity of the optical axis I, and the image-side 12 of the first lens 1 is concave in the vicinity of the optical axis I. The image side surface 32 of the third lens 3 is convex in the vicinity of the optical axis I. The image side surface 42 of the fourth lens 4 is convex in the vicinity of the optical axis I. The object-side surface 11 and the image-side surface 12 of the first lens 1 are both aspherical surfaces.

The detailed optical parameters of the adjustable eye distance adjustable eyepiece system 10 of the second embodiment are shown in Table 5 and Table 6. The aspheric coefficients of each of the object side surface 11 to the image side surface 42 of the fourth lens 4 in the formula (1) in the second embodiment are shown in Table 7. The relationship between the important parameters in the adjustable eye distance adjustable eyepiece system 10 of the second embodiment is shown in Table 8.         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Second embodiment </ td> </ tr> <tr> <td> Effective focal length = 18.7 mm, half field angle (HFOV) = 25.5 degrees </ td> </ tr> <tr> <td> </ td> <td> surface </ td> <td> radius of curvature (mm) </ td > <td> distance (mm) </ td> <td> refractive index </ td> <td> dispersion coefficient </ td> </ tr> <tr> <td> enlarged virtual image </ td> <td> < / td> <td> infinite </ td> <td> D1 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Aperture A </ td> <td> </ td> <td> Infinitely large </ td> <td> D2 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> First lens 1 </ td> <td> Object side 11 </ td> <td> -61.9971 </ td> <td> 1.861 </ td> <td> 1.5 </ td> < td> 57.6 </ td> </ tr> <tr> <td> like side 12 </ td> <td> 43.3166 </ td> <td> 0.045 </ td> </ tr> <tr> <td> Second lens 2 </ td> <td> Object side 21 </ td> <td> 8.5822 </ td> <td> 8.7924 </ td> <td> 1.53 </ td> <td> 56.2 </ td> </ tr> <tr> <td> Image side 22 </ td> <td> -19.0341 </ td> <td> 4.693 </ td> </ tr> <tr> <td> Third lens 3 </ td> <td> object side 31 </ td> <td> -2.104161 </ td> <td> 2.203 </ td> <td> 1.63 </ td> <td> 24.1 </ td> </ tr> < tr> < td> image side 32 </ td> <td> -6.2074 </ td> <td> 0.045 </ td> </ tr> <tr> <td> fourth lens 4 </ td> <td> object side 41 </ td> <td> 4.4726 </ td> <td> 6.6826 </ td> <td> 1.53 </ td> <td> 56.2 </ td> </ tr> <tr> <td> Image side 42 < / td> <td> -53.7521 </ td> <td> D10 (variable) </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Variables </ td> <td> D1 (mm) </ td> <td> D2 ( mm) </ td> <td> D10 (mm) </ td> </ tr> <tr> <td> Diopter (+ 2D) </ td> <td> 500 </ td> <td> 13.3 </ td> <td> 6.9 </ td> </ tr> <tr> <td> Diopter (-8D) </ td> <td> -125 </ td> <td> 17.2 </ td> <td> 3 </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> surface </ td> <td> K </ td> <td> A <sub> 4 </ sub> </ td> <td> A <sub> 6 </ sub> </ td> <td> A <sub> 8 </ sub> </ td> <td> A <sub> 10 </ sub> </ td> <td> A <sub> 12 </ sub> </ td> <td> A <sub> 14 </ sub> </ td> </ tr> <tr> <td> 11 < / td> <td> 35.49168 </ td> <td> 6.16E-04 </ td> <td> -5.81E-06 </ td> <td> 1.48E-08 </ td> <td> 3.74E -10 </ td> <td> -3.88E-12 </ td> <td> 1.51E-14 </ td> </ tr> <tr> <td> 12 </ td> <td> -102.997 < / td> <td> 4.39E-04 </ td> <td> -6.77E-06 </ td> <td> 3.07E-08 </ td> <td> 5.45E-11 </ td> <td > 9.30E-13 </ td> <td> -2.06E-14 </ td> </ tr> <tr> <td> 21 </ td> <td> -0.83988 </ td> <td> -2.41 E-04 </ td> <td> 2.51E-06 </ td> <td> -1.33E-08 </ td> <td> -3.99E-11 </ td> <td> 9.58E-13 < / td> <td> -3.33E-15 </ td> </ tr> <tr> <td> 22 </ td> <td> 1.727095 </ td> <td> -8.50E-05 </ td> <td> 5.53E-06 </ td> <td> -6.60E-09 </ td> <td> -1.83E-10 </ td> <td> -1.23E-12 </ td> <td> 1.10E-14 </ td> </ tr> <tr> <td> 31 </ td> <td> -2.06346 </ td> <td> 1.82E-04 </ td> <td> 1.41E-06 </ td> <td> -1.60E-08 </ td> <td> 5.26E-11 </ td> <td> -5.45E-13 </ td> td> <td> 3.67E-15 </ td> </ tr> <tr> <td> 32 </ td> <td> -6.95947 </ td> <td> 1.63E-04 </ td> <td > -2.19E-06 </ td> <td> 3.27E-08 </ td> <td> -2.17E-10 </ td> <td> 1.25E-12 </ td> <td> -9.53E -15 </ td> </ tr> <tr> <td> 41 </ td> <td> -3.99564 </ td> <td> 4.37E-04 </ td> <td> -6.32E-06 < / td> <td> 8.98E-08 </ td> <td> -9.82E-10 </ td> <td> 6.79E-12 </ td> <td> -2.40E-14 </ td> < / tr> <tr> <td> 42 </ td> <td> -100.037 </ td> <td> 7.08E-04 </ td> <td> -1.09E-05 </ td> <td> 1.06 E-07 </ td> <td> -2.68E-10 </ td> <td> -6.35E-12 </ td> <td> 5.36E-14 </ td> </ tr> </ TBODY> </ TABLE> 表 七         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Φ <sub> 1 </ sub> </ td> <td> -0.01981 </ td > </ tr> <tr> <td> Φ <sub> 2 </ sub> </ td> <td> 0.08072 </ td> </ tr> <tr> <td> Φ <sub> 3 </ sub > </ td> <td> -0.1592 </ td> </ tr> <tr> <td> | Φ <sub> 3 </ sub> / (Φ <sub> 1 </ sub> + Φ <sub> 2 </ sub>) | </ td> <td> -2.6133 </ td> </ tr> <tr> <td> f3 </ td> <td> -6.2814 </ td> </ tr> <tr > <td> | R5 / f3 | </ td> <td> 0.3349 </ td> </ tr> <tr> <td> | V2-V3 | </ td> <td> 32.1 </ td> </ tr> <tr> <td> TTL </ td> <td> 44.77 </ td> </ tr> <tr> <td> D2 (+ 2D) </ td> <td> 13.3 </ td> </ tr> <tr> <td> D2 (-8D) </ td> <td> 17.2 </ td> </ tr> <tr> <td> TTL / D2 (+ 2D) </ td> <td> 3.36 </ td> </ tr> <tr> <td> TTL / D2 (-8D) </ td> <td> 2.6 </ td> </ tr> </ TBODY> </ TABLE>       

FIG. 9 and FIG. 10 are field curvature aberration diagrams when the diopters of the adjustable eye distance system of the second embodiment are + 2D and -8D, respectively. FIG. 11 and FIG. 12 are distortion aberration diagrams when the diopter of the adjustable eyepiece system of the second embodiment is + 2D and -8D. FIG. 13A to FIG. 13F and FIG. 14A to FIG. 14F are transverse beam fan diagrams when the diopter of the eye-adjustable eyepiece system of the second embodiment is + 2D and -8D, respectively. The graphs shown in FIG. 9 to FIG. 14F are all within the standard range, so it can be verified that the adjustable eye distance adjustable eyepiece system 10 of the second embodiment has good imaging quality.

From the above, compared with the conventional display, the adjustable eye distance adjustable eyepiece system 10 of the second embodiment can have a large field angle, good imaging quality, and adjustable adjustable eye distance.

FIG. 15A and FIG. 15B are schematic diagrams when the diopters of a suitable eye distance adjustable eyepiece system according to a third embodiment of the present invention are + 2D and -8D, respectively. 15A and 15B, a third embodiment of the adjustable eye distance adjustable eyepiece system 10 according to the present invention is substantially similar to the second embodiment. The main difference is that the optical data, aspherical coefficients, and parameters between these lenses (first lens 1, second lens 2, third lens 3, and fourth lens 4) are more or less different.

The detailed optical parameters of the adjustable eye distance adjustable eyepiece system 10 of the third embodiment are shown in Tables 9 and 10. The aspheric coefficients of each of the object-side surface 11 to the image-side surface 42 of the fourth lens 4 in the third embodiment in the formula (1) are shown in Table 11. The relationship between important parameters in the adjustable eye distance adjustable eyepiece system 10 of the third embodiment is shown in Table 12.         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Third embodiment </ td> </ tr> <tr> <td> Effective focal length = 17.9 mm, half field angle (HFOV) = 26 degrees </ td> </ tr> <tr> <td> </ td> <td> surface </ td> <td> radius of curvature (mm) </ td > <td> distance (mm) </ td> <td> refractive index </ td> <td> dispersion coefficient </ td> </ tr> <tr> <td> enlarged virtual image </ td> <td> < / td> <td> infinite </ td> <td> D1 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Aperture A </ td> <td> </ td> <td> Infinitely large </ td> <td> D2 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> First lens 1 </ td> <td> Object side 11 </ td> <td> -29.963 </ td> <td> 2.06 </ td> <td> 1.49 </ td> < td> 57.6 </ td> </ tr> <tr> <td> like side 12 </ td> <td> 2491.294 </ td> <td> 0.045 </ td> </ tr> <tr> <td> Second lens 2 </ td> <td> Object side 21 </ td> <td> 8.342 </ td> <td> 11.389 </ td> <td> 1.53 </ td> <td> 56.2 </ td> </ tr> <tr> <td> Image side 22 </ td> <td> -9.722 </ td> <td> 2.542 </ td> </ tr> <tr> <td> Third lens 3 </ td> <td> Object side 31 </ td> <td> -1.997 </ td> <td> 3.3 </ td> <td> 1.58 </ td> <td> 30 </ td> </ tr> < tr> <td> Image side 32 </ td> <td> -16.148 </ td> <td> 0.045 </ td> </ tr> <tr> <td> Fourth lens 4 </ td> <td> Object side 41 </ td> <td> 3.608 </ td> <td> 6.7515 </ td> <td> 1.53 </ td> <td> 56.2 </ td> </ tr> <tr> <td> Like side 42 </ td> < td> -82.694 </ td> <td> D10 (variable) </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Variables </ td> <td> D1 (mm) </ td> <td> D2 ( mm) </ td> <td> D10 (mm) </ td> </ tr> <tr> <td> Diopter (+ 2D) </ td> <td> 500 </ td> <td> 13.3 </ td> <td> 6.45 </ td> </ tr> <tr> <td> Diopter (-8D) </ td> <td> -125 </ td> <td> 17.2 </ td> <td> 2.55 </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> surface </ td> <td> K </ td> <td> A <sub> 4 </ sub> </ td> <td> A <sub> 6 </ sub> </ td> <td> A <sub> 8 </ sub> </ td> <td> A <sub> 10 </ sub> </ td> <td> A <sub> 12 </ sub> </ td> <td> A <sub> 14 </ sub> </ td> </ tr> <tr> <td> 11 < / td> <td> -47.7103 </ td> <td> 6.69E-04 </ td> <td> -7.26E-06 </ td> <td> -3.71E-09 </ td> <td> 5.11E-10 </ td> <td> -1.84E-12 </ td> <td> -6.96E-15 </ td> </ tr> <tr> <td> 12 </ td> <td> -998.237 </ td> <td> 0.000492 </ td> <td> -6.37E-06 </ td> <td> -9.06E-10 </ td> <td> 1.94E-10 </ td> < td> 1.34E-12 </ td> <td> -1.56E-14 </ td> </ tr> <tr> <td> 21 </ td> <td> -0.58362 </ td> <td>- 3.14E-04 </ td> <td> 1.62E-06 </ td> <td> -1.52E-08 </ td> <td> -4.57E-12 </ td> <td> 9.10E-13 </ td> <td> -5.57E-15 </ td> </ tr> <tr> <td> 22 </ td> <td> -0.61055 </ td> <td> 1.18E-04 </ td > <td> 2.06E-06 </ td> <td> -4.17E-10 </ td> <td> -7.86E-11 </ td> <td> -9.22E-13 </ td> <td > 7.99E-15 </ td> </ tr> <tr> <td> 31 </ td> <td> -2.35626 </ td> <td> 1.63E-04 </ td> <td> 1.84E- 07 </ td> <td> -4.78E-09 </ td> <td> 2.17E-11 </ td> <td> -9.43E-13 </ td> <td> 6.64E-15 </ td> </ tr> <tr> <td> 32 </ td> <td> -95.6973 </ td> <td> 2.48E-04 </ td> <td> -1.94E-07 </ td> <td> 1.18E-09 </ td> <td> -1.50E-10 </ td> <td> 1.06E-12 </ td> <td>- 3.01E-15 </ td> </ tr> <tr> <td> 41 </ td> <td> -3.977 </ td> <td> 2.20E-04 </ td> <td> -2.40E- 06 </ td> <td> 6.68E-08 </ td> <td> -1.20E-09 </ td> <td> 1.10E-11 </ td> <td> -4.47E-14 </ td > </ tr> <tr> <td> 42 </ td> <td> 59.92065 </ td> <td> 5.73E-04 </ td> <td> -7.14E-06 </ td> <td> 6.82E-08 </ td> <td> 5.65E-11 </ td> <td> -8.28E-12 </ td> <td> 4.29E-14 </ td> </ tr> </ TBODY> </ TABLE> Table 11         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Φ <sub> 1 </ sub> </ td> <td> -0.01662 </ td > </ tr> <tr> <td> Φ <sub> 2 </ sub> </ td> <td> 0.09258 </ td> </ tr> <tr> <td> Φ <sub> 3 </ sub > </ td> <td> -0.23442 </ td> </ tr> <tr> <td> | Φ <sub> 3 </ sub> / (Φ <sub> 1 </ sub> + Φ <sub> 2 </ sub>) | </ td> <td> -3.08602 </ td> </ tr> <tr> <td> f3 </ td> <td> -4.265 </ td> </ tr> <tr > <td> | R5 / f3 | </ td> <td> 0.46821 </ td> </ tr> <tr> <td> | V2-V3 | </ td> <td> 26.2 </ td> </ tr> <tr> <td> TTL </ td> <td> 45.95 </ td> </ tr> <tr> <td> D2 (+ 2D) </ td> <td> 13.3 </ td> </ tr> <tr> <td> D2 (-8D) </ td> <td> 17.2 </ td> </ tr> <tr> <td> TTL / D2 (+ 2D) </ td> <td> 3.45 </ td> </ tr> <tr> <td> TTL / D2 (-8D) </ td> <td> 2.67 </ td> </ tr> </ TBODY> </ TABLE>       

16 and 17 are diagrams of field curvature aberrations when the diopters of the adjustable eye distance system of the third embodiment are + 2D and -8D, respectively. FIG. 18 and FIG. 19 are distortion aberration diagrams when the refractive power of the adjustable eye distance system of the third embodiment is + 2D and -8D. FIG. 20A to FIG. 20F and FIG. 21A to FIG. 21F are transverse beam fan diagrams when the diopter of the eye-adjustable eyepiece system according to the third embodiment is + 2D and -8D, respectively. The graphs shown in FIG. 16 to FIG. 21F are all within the standard range, so it can be verified that the adjustable eye distance adjustable eyepiece system 10 of the third embodiment has good imaging quality.

From the above, compared with the conventional display, the adjustable eye distance adjustable eyepiece system 10 of the third embodiment can have a large field angle, good imaging quality, and adjustable adjustable eye distance.

22A and 22B are schematic diagrams when the diopters of a suitable eye distance adjustable eyepiece system according to a fourth embodiment of the present invention are + 2D and -8D, respectively. 22A and 22B, a fourth embodiment of the adjustable eye distance adjustable eyepiece system 10 of the present invention is substantially similar to the third embodiment. The main difference is that the optical data, aspherical coefficients, and parameters between these lenses (first lens 1, second lens 2, third lens 3, and fourth lens 4) are more or less different. The object-side surface 11 of the first lens 1 is a convex surface in the vicinity of the optical axis I. The image side surface 22 of the second lens 2 is a concave surface in the vicinity of the optical axis I. The image-side surface 42 of the fourth lens 4 is a concave surface in the vicinity of the optical axis I.

The detailed optical parameters of the adjustable eye distance adjustable eyepiece system 10 of the fourth embodiment are shown in Table 13 and Table 14. Table 15 shows the aspheric coefficients of each of the object side surface 11 to the image side surface 42 of the fourth lens 4 in the formula (1) in the fourth embodiment. The relationship between important parameters in the adjustable eye distance adjustable eyepiece system 10 of the fourth embodiment is shown in Table 16.         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Fourth embodiment </ td> </ tr> <tr> <td> Effective focal length = 19.25 mm, half field of view (HFOV) = 26 degrees </ td> </ tr> <tr> <td> </ td> <td> surface </ td> <td> radius of curvature (mm) </ td > <td> distance (mm) </ td> <td> refractive index </ td> <td> dispersion coefficient </ td> </ tr> <tr> <td> enlarged virtual image </ td> <td> < / td> <td> infinite </ td> <td> D1 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Aperture A </ td> <td> </ td> <td> Infinitely large </ td> <td> D2 (variable) </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> First lens 1 </ td> <td> Object side 11 </ td> <td> 22.8591 </ td> <td> 2.7512 </ td> <td> 1.5 </ td> <td > 57.6 </ td> </ tr> <tr> <td> like side 12 </ td> <td> 9.1029 </ td> <td> 0.1374 </ td> </ tr> <tr> <td> Two lenses 2 </ td> <td> Object side 21 </ td> <td> 6.4197 </ td> <td> 8.3879 </ td> <td> 1.53 </ td> <td> 56.2 </ td> < / tr> <tr> <td> Image side 22 </ td> <td> 18.0115 </ td> <td> 1.0054 </ td> </ tr> <tr> <td> Third lens 3 </ td> <td> Object side 31 </ td> <td> -5.838 </ td> <td> 2 </ td> <td> 1.64 </ td> <td> 22.4 </ td> </ tr> <tr> <td> like Face 32 </ td> <td> -17.9151 </ td> <td> 0.1 </ td> </ tr> <tr> <td> Fourth lens 4 </ td> <td> Object side 41 </ td > <td> 4.5022 </ td> <td> 7.2707 </ td> <td> 1.53 </ td> <td> 56.2 </ td> </ tr> <tr> <td> Like side 42 </ td> <td> 13.4321 </ td> <td> D10 (variable) </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Variables </ td> <td> D1 (mm) </ td> <td> D2 ( mm) </ td> <td> D10 (mm) </ td> </ tr> <tr> <td> Diopter (+ 2D) </ td> <td> 500 </ td> <td> 14.5 </ td> <td> 7.7 </ td> </ tr> <tr> <td> Diopter (-8D) </ td> <td> -125 </ td> <td> 18.1 </ td> <td> 3.9 </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> surface </ td> <td> K </ td> <td> A <sub> 4 </ sub> </ td> <td> A <sub> 6 </ sub> </ td> <td> A <sub> 8 </ sub> </ td> <td> A <sub> 10 </ sub> </ td> <td> A <sub> 12 </ sub> </ td> <td> A <sub> 14 </ sub> </ td> </ tr> <tr> <td> 11 < / td> <td> 1.7130 </ td> <td> 3.20E-04 </ td> <td> -9.84E-08 </ td> <td> -2.33E-07 </ td> <td> 5.36 E-09 </ td> <td> -5.60E-11 </ td> <td> 2.85E-13 </ td> </ tr> <tr> <td> 12 </ td> <td> -0.9348 </ td> <td> -0.00102 </ td> <td> 4.78E-05 </ td> <td> -1.24E-06 </ td> <td> 1.67E-08 </ td> <td> -1.26E-10 </ td> <td> 5.03E-13 </ td> </ tr> <tr> <td> 21 </ td> <td> -1.1688 </ td> <td> -0.00115 < / td> <td> 2.96E-05 </ td> <td> -4.25E-07 </ td> <td> 3.23E-09 </ td> <td> -1.34E-11 </ td> < td> 3.96E-14 </ td> </ tr> <tr> <td> 22 </ td> <td> 0.5688 </ td> <td> -0.00086 </ td> <td> -2.75E-05 </ td> <td> 1.47E-06 </ td> <td> -2.75E-08 </ td> <td> 2.65E-10 </ td> <td> -1.32E-12 </ td> </ tr> <tr> <td> 31 </ td> <td> -8.9628 </ td> <td> 0.001348 </ td> <td> -4.99E-05 </ td> <td> 9.63E- 07 </ td> <td> -1.04E-08 </ td> <td> 5.98E-11 </ td> <td>- 1.65E-13 </ td> </ tr> <tr> <td> 32 </ td> <td> -99 </ td> <td> 0.001079 </ td> <td> 1.88E-06 </ td > <td> -1.09E-06 </ td> <td> 3.07E-08 </ td> <td> -3.96E-10 </ td> <td> 2.49E-12 </ td> </ tr > <tr> <td> 41 </ td> <td> -3.1571 </ td> <td> 7.55E-04 </ td> <td> -1.34E-05 </ td> <td> -7.09E -08 </ td> <td> 5.44E-09 </ td> <td> -7.99E-11 </ td> <td> 5.51E-13 </ td> </ tr> <tr> <td> 42 </ td> <td> -41.5911 </ td> <td> 0.001689 </ td> <td> -3.01E-05 </ td> <td> -3.49E-07 </ td> <td> 2.28 E-08 </ td> <td> -3.80E-10 </ td> <td> 2.80E-12 </ td> </ tr> </ TBODY> </ TABLE>         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> Φ <sub> 1 </ sub> </ td> <td> -0.031 </ td > </ tr> <tr> <td> Φ <sub> 2 </ sub> </ td> <td> 0.0667 </ td> </ tr> <tr> <td> Φ <sub> 3 </ sub > </ td> <td> -0.0702 </ td> </ tr> <tr> <td> | Φ <sub> 3 </ sub> / (Φ <sub> 1 </ sub> + Φ <sub> 2 </ sub>) | </ td> <td> -1.9621 </ td> </ tr> <tr> <td> f3 </ td> <td> -14.2367 </ td> </ tr> <tr > <td> | R5 / f3 | </ td> <td> 0.41 </ td> </ tr> <tr> <td> | V2-V3 | </ td> <td> 33.8 </ td> </ tr> <tr> <td> TTL </ td> <td> 45 </ td> </ tr> <tr> <td> D2 (+ 2D) </ td> <td> 14.5 </ td> </ tr> <tr> <td> D2 (-8D) </ td> <td> 18.1 </ td> </ tr> <tr> <td> TTL / D2 (+ 2D) </ td> <td> 3.1 </ td> </ tr> <tr> <td> TTL / D2 (-8D) </ td> <td> 2.48 </ td> </ tr> </ TBODY> </ TABLE>       

FIG. 23 and FIG. 24 are field curvature aberration diagrams when the diopters of the adjustable eye distance adjustable eyepiece system according to the fourth embodiment are + 2D and -8D, respectively. 25 and 26 are distortion aberration diagrams when the diopter of the adjustable eye distance system of the fourth embodiment is + 2D and -8D. FIG. 27A to FIG. 27F and FIG. 28A to FIG. 28F are transverse beam fan diagrams when the diopter of the eye-adjustable eyepiece system of the fourth embodiment is + 2D and -8D, respectively. The figures shown in FIG. 23 to FIG. 28F are all within the standard range, so it can be verified that the eye-adjustable eyepiece system 10 of the fourth embodiment has good imaging quality.

From the above, compared to the conventional display, the adjustable eye distance adjustable eyepiece system 10 of the fourth embodiment can have a large field angle, good imaging quality, and adjustable adjustable eye distance.

In summary, the adjustable eye distance adjustable eyepiece system according to the embodiment of the present invention can achieve the following effects and advantages: by designing and arranging the concave and convex shapes of the object side or the image side of the four lenses, the appropriate eye distance can be adjusted. The eyepiece system has a large field of view, good imaging quality, and adjustable eye distance. Further, the first lens has a refractive power, which is suitable for controlling a field angle of an adjustable eyepiece system with a proper eye distance. The second lens has a positive refractive power, which helps the first lens to receive more light beams and correct spherical aberration. The third lens has a negative refractive power, which is suitable for compensating chromatic aberration. A second lens with a positive refractive power and a third lens with a negative refractive power can reduce the Pezval sum of the adjustable eye distance system and effectively correct the field curvature. The fourth lens has a positive refractive power, and at least one of the object-side surface and the image-side surface is aspheric, which is advantageous for adjusting distortion. By adjusting the positions of the four lenses between the aperture and the display, the proper eye distance can be adjusted without changing the distance between the aperture and the display, so that the adjustable eye distance eyepiece system has a fixed size and streamlined assembly. . In addition, because the adjustable eye distance system can adjust the appropriate eye distance according to the degree of nearsightedness or farsightedness of the user's eyes, so that the user can clearly see the image displayed on the monitor under the naked eye condition. When the monitor is equipped with an adjustable eye distance eyepiece system, the user may not need to wear an additional vision correction device. In this way, the wearing weight of the user can be reduced and the burden of long-term use can be reduced. When 0.7 <| Φ3 / (Φ1 + Φ2) | <4.5 is satisfied, high resolution can be achieved. When 0 <| R5 / f3 | <3.5 is satisfied, it is advantageous for correction of low-order aberrations. When | V2-V3 |> 20 is satisfied, the ability to correct chromatic aberration can be improved. When 1.5 <TTL / D2 <5.5, images with different diopters can be clearly analyzed. In addition, by replacing the free-form lens with an aspheric lens, in addition to simplifying design and manufacturing difficulties, it can also reduce costs and manufacturing tolerances.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

1‧‧‧first lens
2‧‧‧Second lens
3‧‧‧ third lens
4‧‧‧ fourth lens
9‧‧‧ Display
10‧‧‧ Adjustable Eyepiece Eyepiece System
11, 21, 31, 41‧‧‧ side
12, 22, 32, 42‧‧‧ like side
A‧‧‧ aperture
I‧‧‧ Optical axis

FIG. 1A and FIG. 1B are schematic diagrams when the diopters of an adjustable eye distance adjustable eyepiece system according to the first embodiment of the present invention are + 2D and -8D, respectively. FIG. 2 and FIG. 3 are field curvature aberration diagrams when the diopters of the adjustable eyepiece system of the first embodiment are + 2D and -8D, respectively. FIG. 4 and FIG. 5 are distortion aberration diagrams when the refractive power of the adjustable eyepiece system of the first embodiment is + 2D and -8D. FIG. 6A to FIG. 6F and FIG. 7A to FIG. 7F are transverse beam fan diagrams when the diopter of the adjustable eye distance system of the first embodiment is + 2D and -8D, respectively. 8A and FIG. 8B are schematic diagrams when the diopters of an adjustable eye distance adjustable eyepiece system according to the second embodiment of the present invention are + 2D and -8D, respectively. FIG. 9 and FIG. 10 are field curvature aberration diagrams when the diopters of the adjustable eye distance system of the second embodiment are + 2D and -8D, respectively. FIG. 11 and FIG. 12 are distortion aberration diagrams when the diopter of the adjustable eyepiece system of the second embodiment is + 2D and -8D. FIG. 13A to FIG. 13F and FIG. 14A to FIG. 14F are transverse beam fan diagrams when the diopter of the eye-adjustable eyepiece system of the second embodiment is + 2D and -8D, respectively. FIG. 15A and FIG. 15B are schematic diagrams when the diopters of a suitable eye distance adjustable eyepiece system according to a third embodiment of the present invention are + 2D and -8D, respectively. 16 and 17 are diagrams of field curvature aberrations when the diopters of the adjustable eye distance system of the third embodiment are + 2D and -8D, respectively. FIG. 18 and FIG. 19 are distortion aberration diagrams when the refractive power of the adjustable eye distance system of the third embodiment is + 2D and -8D. FIG. 20A to FIG. 20F and FIG. 21A to FIG. 21F are transverse beam fan diagrams when the diopter of the eye-adjustable eyepiece system according to the third embodiment is + 2D and -8D, respectively. 22A and 22B are schematic diagrams when the diopters of a suitable eye distance adjustable eyepiece system according to a fourth embodiment of the present invention are + 2D and -8D, respectively. FIG. 23 and FIG. 24 are field curvature aberration diagrams when the diopters of the adjustable eye distance adjustable eyepiece system according to the fourth embodiment are + 2D and -8D, respectively. 25 and 26 are distortion aberration diagrams when the diopter of the adjustable eye distance system of the fourth embodiment is + 2D and -8D. FIG. 27A to FIG. 27F and FIG. 28A to FIG. 28F are transverse beam fan diagrams when the diopter of the eye-adjustable eyepiece system of the fourth embodiment is + 2D and -8D, respectively.

Claims (10)

An adjustable eye distance eyepiece system includes an aperture, a first lens having a refractive power, a second lens having a positive refractive power, and a third lens having a negative refractive power in order along an optical axis from the object side to the image side. And a fourth lens having positive refractive power, wherein the first lens to the fourth lens are adapted to move toward the object side or the image side together according to the user's proper eye distance, and the first lens to the fourth lens are each Including an object side facing the object side and passing the imaging light and an image side facing the image side and passing the imaging light, the adjustable eye distance adjustable eyepiece system satisfies: 0 <| R5 / f3 | <3.5; where R5 is The curvature radius of the object side of the third lens, and f3 is the focal length of the third lens. As described in item 1 of the patent application scope, the adjustable eye distance adjustable eyepiece system also satisfies: 0.7 <| Φ3 / (Φ1 + Φ2) | <4.5; where Φ1 is the reciprocal of the focal length of the first lens and Φ2 is the The reciprocal of the focal length of the second lens, and Φ3 is the reciprocal of the focal length of the third lens. According to the adjustable eye distance adjustable eyepiece system described in item 1 of the scope of patent application, it also satisfies: | V2-V3 |> 20; where V2 is the dispersion coefficient of the second lens and V3 is the dispersion coefficient of the third lens . As described in item 1 of the patent application scope, the adjustable eye distance adjustable eyepiece system also satisfies: 1.5 <TTL / D2 <5.5; where TTL is the distance from the aperture to a display on the optical axis, and D2 is the aperture The distance to the object side of the first lens on the optical axis. The eye-adjustable adjustable eyepiece system according to item 1 of the scope of patent application, wherein the object side of the second lens is convex in the vicinity of the optical axis, and the object side and the image side of the second lens At least one of the third lens is aspherical, the object side of the third lens is concave near the optical axis, and at least one of the object side and the image side of the third lens is aspheric, the fourth The object side surface of the lens is convex in the vicinity of the optical axis, and at least one of the object side surface and the image side surface of the fourth lens is aspheric. The adjustable eye distance adjustable eyepiece system according to item 5 of the scope of patent application, wherein the refractive power of the first lens is positive, the object side of the first lens is convex in the vicinity of the optical axis, and the second lens is convex. The image side surface of the lens is convex in a region near the optical axis, and the image side surface of the fourth lens is concave in a region near the optical axis. The adjustable eye distance adjustable eyepiece system according to item 5 of the scope of patent application, wherein the refractive power of the first lens is negative, the image side of the first lens is concave in the vicinity of the optical axis, and the first lens is concave. The image side surfaces of the three lenses are convex in the vicinity of the optical axis. The eye-adjustable adjustable eyepiece system according to item 7 of the scope of patent application, wherein the object side of the first lens is concave in the vicinity of the optical axis, and the image side of the second lens is in the optical axis. The nearby area is convex, and the image side of the fourth lens is convex near the optical axis. The eye-adjustable adjustable eyepiece system according to item 7 of the scope of patent application, wherein the object side of the first lens is convex in the vicinity of the optical axis, and the image side of the second lens is in the optical axis. The nearby area is concave, and the image side of the fourth lens is concave in the vicinity of the optical axis. The eye-adjustable adjustable eyepiece system according to item 1 of the scope of patent application, wherein the object side and the image side of each of the second lens, the third lens, and the fourth lens are aspheric surfaces.