CN108398784B

CN108398784B - Head-mounted display device adopting optical eyepiece lens

Info

Publication number: CN108398784B
Application number: CN201810185453.4A
Authority: CN
Inventors: 林桂春; 其他发明人请求不公开姓名
Original assignee: Individual
Current assignee: Kunming Xunyang Technology Co.,Ltd.
Priority date: 2015-11-16
Filing date: 2015-11-16
Publication date: 2019-12-20
Anticipated expiration: 2035-11-16
Also published as: CN108398784A; CN108303795A; CN108415152B; CN108303795B; CN105388609A; CN105388609B; CN108398785A; CN108415152A; CN108398785B

Abstract

The invention discloses a head-mounted display device adopting an optical eyepiece lens, which sequentially comprises a diaphragm, a first lens, a second lens and a third lens from the observation side of human eyes to the image source side along an optical axis, wherein the first lens, the second lens and the third lens all have refractive indexes and respectively comprise an image side surface facing the observation side and allowing imaging light rays to pass and an object side surface facing the image source side and allowing the imaging light rays to pass; the first lens and the third lens are positive lenses; the second lens is a negative lens; the first lens is a biconvex lens; the second lens is a plano-concave lens, a biconcave lens or a meniscus lens; the third lens is an aspheric lens. The invention provides an optical eyepiece lens and a head-mounted display device which can keep good optical performance under the condition of shortening the length of a lens system.

Description

Head-mounted display device adopting optical eyepiece lens

Technical Field

The present disclosure relates to optical eyepiece lenses, and particularly to a head-mounted display device using an optical eyepiece lens.

Background

Head-mounted display devices are popular with consumers due to their small size and light weight. Especially, the large field angle of the equipment can create an immersive and shocking visual effect for the user, so that the user can watch the film as if the user is in a movie theater projection hall.

In the prior art, an image source device of a head-mounted display device widely adopts a whole large-sized OLED (organic light-emitting diode) and lcd (liquid crystal display) screen, and a lens used in combination has the characteristics of short working distance, short exit pupil distance, long focal length, low magnification and the like, but the screen resolution is slightly insufficient on a single eye on average. While another type of display device, such as dlp (digital light processing) and lcos (liquid crystal on silicon), can provide a small-sized and high-resolution display, it needs to provide additional illumination to display, so that the lens matched with the display device must have a longer working distance and a smaller field angle.

For a large-field-angle eyepiece of a head-mounted display device, chromatic aberration of magnification, curvature of field and astigmatism are aberrations affecting imaging quality, and in order to avoid reduction of imaging effect and quality, good optical performance is still considered when the length of an optical eyepiece lens is shortened.

Chinese patent publication nos. CN104635333A, CN104536129A, and CN101887166A disclose three optical eyepiece lenses respectively, but still have the problems of short exit pupil distance, short working distance, and small magnification, etc. among them, the length of the exit pupil distance of the CN101887166A lens is within 11mm, which is not suitable for users wearing glasses.

Wear display device on the existing market, all reach the user demand who satisfies the different diopters of user through adjusting eyepiece and screen interval, but none can solve myopia, hyperopia and astigmatism problem simultaneously when the user wears for a long time, and these problems all can influence user's with eye healthy.

Therefore, when a high-pixel small-size display screen is used, it is an urgent need to solve the problem in the art how to effectively shorten the system length of the optical lens, maintain a long working distance and a long exit pupil distance, and maintain sufficient optical performance.

Disclosure of Invention

The present invention is directed to overcome the deficiencies of the prior art and to provide an optical eyepiece lens that can maintain good optical performance while shortening the length of the lens system.

The technical scheme adopted by the invention for solving the technical problems is as follows: an optical eyepiece lens sequentially comprises a diaphragm, a first lens, a second lens and a third lens from an observation side of a human eye to an image source side along an optical axis, wherein the first lens, the second lens and the third lens all have refractive indexes and respectively comprise an image side surface facing the observation side and allowing imaging light rays to pass and an object side surface facing the image source side and allowing the imaging light rays to pass;

and the first lens, the second lens and the third lens meet the following requirements:

Nd1>1.88，Nd2>1.94，Nd3>1.49；Vd1<40.9，Vd2<18.0，Vd3<57.4；

the Nd1, Nd2 and Nd3 respectively represent the refractive indexes of the first lens, the second lens and the third lens at the d line; vd1, Vd2, Vd3 respectively represent the abbe number of the first lens, the second lens, the third lens in d-line;

the first lens, the second lens and the third lens satisfy the following relational expressions:

1)0.90<f1/f<1.40；2)1.40<|f2/f|<2.20；3)1.10<f3/f<2.00；

the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, and the system focal length is f.

Preferably, the first lens and the third lens are positive lenses; the second lens is a negative lens.

Preferably, the first lens is a biconvex lens; the second lens is a plano-concave lens, a biconcave lens or a meniscus lens; the third lens is an aspheric lens.

Preferably, the object-side surface and the image-side surface of the third lens have aspheric expressions:

wherein Y is the distance between a point on the aspheric curve and the optical axis I; z is the depth of the aspheric surface (the vertical distance between the point on the aspheric surface which is Y away from the optical axis I and the tangent plane tangent to the vertex on the optical axis I of the aspheric surface); r is the radius of curvature of the lens surface; k is cone constant; a2i is the 2 i-th order aspheric coefficient.

Preferably, an optical axis distance between the object-side surface of the third lens and the image source surface is BFL, an optical axis thickness of the third lens is T3, an optical axis air gap between the second lens and the third lens is G23, and the following relations are satisfied: BFL/T3< 3.00; T3/G23 ≦ 71; BFL/G23 ≦ 105.

Preferably, the first lens and the second lens are adhered to each other by a photosensitive adhesive; the focal length of the cemented lens formed by the first lens and the second lens is f12, the thickness of the first lens on the optical axis is T1, the thickness of the second lens on the optical axis is T2, the thickness of the cemented lens formed by the first lens and the second lens on the optical axis is T12, and the following relations are also satisfied: T1/T2 ≧ 3.5; t12 ═ T1+ T2; T12/T3 ≧ 0.75; 1.50< f12/f < 3.20.

Preferably, the first lens and the second lens are made of glass, and the third lens is made of plastic.

Preferably, the distance from the image side surface of the first lens to the image source surface on the optical axis is TTL, the sum of the thicknesses of the first lens, the second lens and the third lens on the optical axis is ALT, and the following relation is satisfied: BFL/TTL is not less than 0.30; ALT/TTL ≦ 0.70; ALT/T12 ≧ 1.35.

The optical eyepiece lens has the advantages that: the first lens and the third lens are positive lenses; the second lens is a negative lens; the first lens is a biconvex lens; the second lens is a plano-concave lens, a biconcave lens or a meniscus lens; the third lens is an aspheric lens; by means of the selection and mutual matching of the optical parameters of the first lens, the second lens and the third lens, the aberration can be corrected, and the imaging quality of the optical eyepiece lens can be improved. In addition, the first lens and the second lens are made of glass materials, and the larger refractive index of the first lens and the second lens can better turn light rays; the first lens and the second lens are combined into a group of cemented lenses, which can perform better correction function on chromatic aberration; the third lens is made of plastic material, which can reduce the manufacturing cost and the weight of the optical eyepiece lens.

Therefore, another object of the present invention is to provide a head-mounted display device using the optical eyepiece lens.

Accordingly, the head-mounted display device of the present invention includes a housing and a display module mounted in the housing.

The display module comprises the optical eyepiece lens and an image source display screen arranged on the object side of the optical eyepiece lens.

Preferably, the total length of the optical eyepiece lens is less than 45 mm. The total length of the optical eyepiece lens is the total length from the diaphragm to an image source display screen on the object side, and the total length comprises a reserved exit pupil distance of at least 20 mm.

Preferably, the distance between the observation point of the eyepiece lens for observation by the human eye and the image side surface of the first lens on the optical axis is greater than 20 mm.

The image source display screen adopts a 0.37-inch LCOS display screen with WXGA (1366 x 768) display resolution, compared with the traditional micro display screen, the LCOS display screen has much smaller pixel size, can effectively reduce the phenomenon of generating particles after being amplified by an optical eyepiece lens, and improves user experience.

The head-mounted display equipment has the beneficial effects that: by mounting the display module with the optical eyepiece lens in the equipment, the eyepiece lens can still provide the advantage of good optical performance under the condition of shortening the system length, and thinner and lighter head-mounted display equipment can be manufactured under the condition of not sacrificing the optical performance, so that the invention has good practical performance and is beneficial to the structural design of light weight, thinness, shortness and miniaturization so as to meet the consumption requirement of higher quality.

The invention is further explained in detail with the accompanying drawings and the embodiments; an optical eyepiece lens and a head-mounted display device of the present invention are not limited to the embodiments.

Drawings

Fig. 1 is a schematic configuration diagram of an optical eyepiece lens according to a first embodiment of the present invention;

FIG. 2 is a diagram of longitudinal spherical aberration and various aberrations of the first embodiment of the present invention;

FIG. 3 is a tabular diagram of optical data for each lens of the first embodiment of the present invention;

FIG. 4 is a table diagram of aspherical coefficients of respective lenses of the first embodiment of the invention;

fig. 5 is a schematic configuration diagram of an optical eyepiece lens according to a second embodiment of the present invention;

FIG. 6 is a diagram of longitudinal spherical aberration and various aberrations for a second embodiment of the present invention;

FIG. 7 is a tabular representation of optical data for each lens of the second embodiment of the present invention;

FIG. 8 is a table diagram of aspherical coefficients of respective lenses of the second embodiment of the invention;

fig. 9 is a schematic configuration diagram of an optical eyepiece lens according to a third embodiment of the present invention;

FIG. 10 is a longitudinal spherical aberration and various aberrations diagram of the third embodiment of the present invention;

FIG. 11 is a tabular diagram of optical data for each lens of the third embodiment of the present invention;

FIG. 12 is a table diagram of aspherical coefficients of respective lenses of the third embodiment of the invention;

fig. 13 is a schematic configuration diagram of an optical eyepiece lens according to a fourth embodiment of the present invention;

FIG. 14 is a longitudinal spherical aberration and various aberrations diagram of the fourth embodiment of the present invention;

FIG. 15 is a tabular representation of optical data for each lens of the fourth embodiment of the present invention;

FIG. 16 is a table diagram of aspherical coefficients of respective lenses of the fourth embodiment of the invention;

fig. 17 is a schematic configuration diagram of an optical eyepiece lens according to a fifth embodiment of the present invention;

FIG. 18 is a longitudinal spherical aberration and various aberrations diagram of the fifth embodiment of the present invention;

FIG. 19 is a tabular diagram of optical data for each lens of a fifth embodiment of the present invention;

FIG. 20 is a table diagram of aspherical coefficients of respective lenses of the fifth embodiment of the invention;

fig. 21 is a schematic configuration diagram of an optical eyepiece lens according to a sixth embodiment of the present invention;

FIG. 22 is a longitudinal spherical aberration and various aberrations diagram of the sixth embodiment of the present invention;

FIG. 23 is a tabular diagram of optical data for each lens of a sixth embodiment of the present invention;

FIG. 24 is a table diagram of aspherical coefficients of respective lenses of a sixth embodiment of the invention;

fig. 25 is a schematic configuration diagram of an optical eyepiece lens according to a seventh embodiment of the present invention;

FIG. 26 is a longitudinal spherical aberration and various aberrations diagram of the seventh embodiment of the present invention;

FIG. 27 is a table diagram of optical data for each lens of the seventh embodiment of the present invention;

FIG. 28 is a table diagram of aspherical coefficients of respective lenses of the seventh embodiment of the invention;

fig. 29 is a schematic configuration diagram of an optical eyepiece lens according to an eighth embodiment of the present invention;

FIG. 30 is a longitudinal spherical aberration and various aberrations diagram of the eighth embodiment of the present invention;

FIG. 31 is a tabular diagram of optical data for each lens of the eighth embodiment of the present invention;

FIG. 32 is a table diagram of aspherical coefficients of respective lenses of the eighth embodiment of the invention;

FIG. 33 is a first table of optical parameters for the first through eighth embodiments of the present invention;

fig. 34 is a table two of optical parameters of the first to eighth embodiments of the present invention.

Detailed Description

Before the present invention is described in detail, it should be noted that in the following description, similar components are denoted by the same reference numerals.

In the present specification, the term "lens has positive refractive index (or negative refractive index)" refers to the lens having positive refractive index (or negative refractive index) in the region near the optical axis. The phrase "the object-side surface (or image-side surface) of the lens has a convex surface portion (or concave surface portion) in a region" means that the region is more "convex outward" (or "concave inward") in a direction parallel to the optical axis than the region immediately outside the region in the radial direction. The "" area near the optical axis "" refers to the area near the optical axis of the curved surface through which only the imaging light passes. In addition, the lens further includes an extension portion for assembling the lens in the eyepiece lens, and the ideal imaging light does not pass through the extension portion.

First embodiment

Referring to fig. 1 and 3, the first embodiment of the optical eyepiece lens 10 of the present invention includes, in order along an optical axis I, a stop 2, a first lens 3, a second lens 4, a third lens 5, and a cover glass 6 from an observation side to an image source side. When light emitted by the display screen 100 enters the optical eyepiece lens 10, passes through the rear part of the protective glass 6, the third lens 5, the second lens 4, the first lens 3 and the diaphragm 2, enters human eyes and forms an erect and enlarged image. It is added that the object side is the side facing the image source, and the image side is the side facing the observer.

The first lens element 3, the second lens element 4, the third lens element 5, and the cover glass 6 each have an image side surface 31, 41, 51, 61 facing the image side and allowing passage of the imaging light, and an object side surface 32, 42, 52, 62 facing the object side and allowing passage of the imaging light. Wherein, the image side surfaces 31, 41 and the object side surfaces 32, 42 are spherical surfaces. The image-side surface 51 and the object-side surface 52 are aspheric.

In addition, in order to satisfy the requirement of light weight of the product, the first lens element 3 and the second lens element 4 are made of glass material with high refractive index, and the third lens element 5 is made of plastic material with refractive index, but the material of the first lens element 3 and the second lens element 4 is not limited thereto.

The first lens element 3 has a positive refractive index. The image-side surface 31 of the first lens element 3 is convex, and the object-side surface 32 of the first lens element 3 is convex. The second lens element 4 has a negative refractive index. The image-side surface 41 of the second lens element 4 is concave, and the object-side surface 42 of the second lens element 4 is planar. The third lens element 5 has a positive refractive index, the image-side surface 51 of the third lens element 5 has a convex portion 511 located in the vicinity of the optical axis I and a convex portion 512 located in the vicinity of the circumference, and the object-side surface 52 of the third lens element 5 has a convex portion 521 located in the vicinity of the optical axis I and a convex portion 522 located in the vicinity of the circumference.

In the first embodiment, only the lens elements have refractive indexes.

Usually, the pupil diameter of the human eye is between 2-4mm when observing things normally, and for convenience of expression, the pupil diameter is currently 3mm on average.

Other detailed optical data of the first embodiment is shown in fig. 3, and the overall system focal length (EFL) of the first embodiment is 12.71mm, the half field of view (HFOV) is 20.5 °, the exit pupil diameter is 3mm, and the system length is 40.34 mm. Wherein the system length refers to the distance on the optical axis I from the position of the diaphragm 2 to the image source surface 100.

In addition, the image-side surface 51 and the object-side surface 52 of the third lens element 5 have aspheric surfaces defined by the following formula:

---（1）

wherein: y: the distance between a point on the aspheric curve and the optical axis I; z: the depth of the aspheric surface (the vertical distance between a point on the aspheric surface which is Y away from the optical axis I and a tangent plane tangent to the vertex on the optical axis I of the aspheric surface); r is the curvature radius of the lens surface; k: cone constant (conc constant); a2 i: aspheric coefficients of order 2 i.

The aspheric coefficients of the image-side surface 51 and the object-side surface 52 of the third lens element 5 in formula (1) are shown in fig. 4. In fig. 4, the field number 51 indicates that it is an aspheric coefficient of the image-side surface 51 of the third lens 5, and so on.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the first embodiment.

Wherein: t1 is the thickness of the first lens 3 on the optical axis I; t2 is the thickness of the second lens 4 on the optical axis I; t12 is the thickness of the cemented lens formed by the first lens 3 and the second lens 4 on the optical axis I; t3 is the thickness of the third lens 5 on the optical axis I; g23 is an air gap on the optical axis I of the second lens 4 to the third lens 5; g3CG is an air gap on the optical axis I from the third lens 5 to the cover glass 6; TCG is the thickness of the cover glass 6 on the optical axis I; GCD is an air gap on the optical axis I from the protective glass 6 to the image source surface 100; ALT is the sum of thicknesses of the first lens 3, the second lens 4, and the third lens 5 on the optical axis I, i.e., the sum of T1, T2, and T3; TTL is the distance from the image side surface 31 of the first lens element 3 to the image source surface 100 on the optical axis I; BFL is the distance on the optical axis I from the object-side surface 52 of the third lens 5 to the image source surface 100, i.e. the sum of G3CG, TCG, GCD; FFL is the distance on the optical axis I from the diaphragm 2 to the image source plane 100; f is the system focal length of the optical eyepiece lens 10; f1 is the focal length of the first lens 3; f2 is the focal length of the second lens 4; f12 is the focal length of the cemented lens formed by the first lens 3 and the second lens 4; f3 is the focal length of the third lens 5.

Referring to fig. 2, the diagram of (a) illustrates the distortion aberration (aberration) of the first embodiment on the image source surface 100, the diagrams of (b) and (c) illustrate the astigmatism aberration (aberration) of the first embodiment in the meridional (tangential) direction and the astigmatism aberration (sagittal) direction on the image source surface 100, respectively, and the diagram of (d) illustrates the longitudinal spherical aberration (longitudinal spherical aberration) of the first embodiment. The distortion aberration diagram of fig. 2(a) shows that the distortion aberration of the first embodiment is maintained within ± 2%, which indicates that the distortion aberration of the first embodiment meets the imaging quality requirement of the optical system. In the two astigmatic aberration diagrams of FIGS. 2(b) and (c), the variation of the focal length of the three representative wavelengths over the entire field of view is within + -0.5 mm, which illustrates that the optical system of the first embodiment can effectively eliminate the aberrations.

In the longitudinal spherical aberration diagram of the first embodiment shown in fig. 2(d), the curves formed by each wavelength are very close and close to the middle, which means that the off-axis light beams with different heights of each wavelength are all concentrated near the imaging point, and the deviation of the off-axis light beams with different heights is controlled within the range of ± 0.03mm as can be seen from the deviation of the curve of each wavelength, so that the present embodiment indeed improves the spherical aberration with the same wavelength, and in addition, the distances between the three representative wavelengths are very close, which means that the imaging positions of the light beams with different wavelengths are very concentrated, thereby improving the chromatic aberration. Therefore, compared with the conventional optical lens, the first embodiment can provide better imaging quality under the condition that the system length is shortened to 40.34mm while the exit pupil distance is kept at 20mm, so that the first embodiment can shorten the lens length to realize thinner product design under the condition of maintaining good optical performance.

Second embodiment

Referring to fig. 5, a second embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, wherein the second embodiment is mainly different from the first embodiment in that: the object-side surface 42 of the second lens element 4 is convex (42), and the object-side surface 52 of the third lens element 5 has a concave portion 522 located in the vicinity of the circumference, and it should be noted that the same reference numerals for the concave and convex portions as those in the first embodiment are omitted in fig. 5 for clarity of illustration.

The detailed optical data is shown in fig. 7, and the overall system focal length of this second embodiment is 12.69mm, half field of view (HFOV) is 20.5 °, exit pupil diameter is 3mm, and system length is 41.49 mm. As shown in fig. 8, the aspheric coefficients of the terms from the image-side surface 51 to the object-side surface 52 of the third lens element 5 in the formula (1) are shown.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the second embodiment.

Referring to fig. 6, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the second embodiment can maintain good optical performance.

Third embodiment

Referring to fig. 9, a third embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, and only the optical data, aspheric coefficients and parameters of the lenses 3, 4 and 5 are slightly different, and it should be noted that the same reference numerals for the concave and convex portions as those of the first embodiment are omitted in fig. 9 for clarity of illustration.

The detailed optical data is shown in fig. 11, and the overall system focal length of the third embodiment is 12.22mm, half field of view (HFOV) is 20.5 °, exit pupil diameter is 3mm, and system length is 41.51 mm. As shown in fig. 12, the aspheric coefficients of the terms from the image-side surface 51 to the object-side surface 52 of the third lens element 5 in the formula (1) are shown.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the third embodiment.

Referring to fig. 10, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the third embodiment can maintain good optical performance.

Fourth embodiment

Referring to fig. 13, a fourth embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, and only the optical data, aspheric coefficients and parameters of the lenses 3, 4 and 5 are slightly different, and it should be noted that the same reference numerals for the concave and convex portions as those of the first embodiment are omitted in fig. 13 for clarity of illustration.

The detailed optical data is shown in fig. 15, and the overall system focal length of the fourth embodiment is 12.71mm, half field of view (HFOV) is 20.5 °, exit pupil diameter is 3mm, and system length is 42.38 mm. As shown in fig. 16, the aspheric coefficients of the terms from the image-side surface 51 to the object-side surface 52 of the third lens element 5 in the formula (1) in the fourth embodiment are shown.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the fourth embodiment.

Referring to fig. 14, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the fourth embodiment can maintain good optical performance.

Fifth embodiment

Referring to fig. 17, a fifth embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, wherein the fifth embodiment is mainly different from the first embodiment in that: the object side surface 42 of the second lens element 4 is a concave surface (42), and it should be noted that the same reference numerals for the concave and convex portions as those in the first embodiment are omitted in fig. 17 for clarity of illustration.

The detailed optical data is shown in fig. 19, and the overall system focal length of the fifth embodiment is 12.78mm, half field of view (HFOV) is 20.5 °, exit pupil diameter is 3mm, and system length is 41.51 mm. As shown in fig. 20, the aspheric coefficients of the terms in formula (1) from the image-side surface 51 to the object-side surface 52 of the third lens 5 of the fifth embodiment are shown.

Fig. 33 and 34 show the relationship between important parameters in the optical eyepiece lens 10 according to the fifth embodiment.

Referring to fig. 18, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the fifth embodiment can maintain good optical performance.

Sixth embodiment

Referring to fig. 21, a sixth embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, wherein the sixth embodiment is mainly different from the first embodiment in that: the object side surface 42 of the second lens element 4 is convex (42), and it should be noted that the same reference numerals for the concave and convex portions as in the first embodiment are omitted in fig. 21 for clarity of illustration.

The detailed optical data is shown in fig. 23, and the overall system focal length of the sixth embodiment is 12.72mm, half field of view (HFOV) is 20.5 °, exit pupil diameter is 3mm, and system length is 43.96 mm. As shown in fig. 24, the aspheric coefficients of the terms from the image-side surface 51 to the object-side surface 52 of the third lens element 5 in the formula (1) in the sixth embodiment.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the sixth embodiment.

Referring to fig. 22, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the sixth embodiment can maintain good optical performance.

Seventh embodiment

Referring to fig. 25, a seventh embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, and only the optical data, aspheric coefficients and parameters between the lenses 3, 4 and 5 are slightly different, and it should be noted that the same reference numerals for the concave and convex portions as those of the first embodiment are omitted in fig. 25 for clarity of illustration.

The detailed optical data is shown in fig. 27, and the overall system focal length of the seventh embodiment is 12.74mm, half field of view (HFOV) is 20.5 °, exit pupil diameter is 3mm, and system length is 44.31 mm. As shown in fig. 28, the aspheric coefficients of the terms from the image-side surface 51 to the object-side surface 52 of the third lens 5 in the formula (1) are shown in the seventh embodiment.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the seventh embodiment.

Referring to fig. 26, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the seventh embodiment can maintain good optical performance.

Eighth embodiment

Referring to fig. 29, an eighth embodiment of the optical eyepiece lens 10 of the present invention is substantially similar to the first embodiment, wherein the eighth embodiment is mainly different from the first embodiment in that: it should be noted that, in fig. 29, the same reference numerals as those of the concave portion and the convex portion in the first embodiment are omitted for clarity of illustration, in which the image-side surface 51 of the third lens element 5 is concave and has the concave portion 511 located in the vicinity of the optical axis I, and the object-side surface 52 of the third lens element 5 is convex and has the concave portion 522 located in the vicinity of the circumference.

The detailed optical data is shown in fig. 31, and the overall system focal length of the eighth embodiment is 12.70mm, the half field of view (HFOV) is 20.5 °, the exit pupil diameter is 3mm, and the system length is 40.43 mm. As shown in fig. 32, the aspheric coefficients of the terms in formula (1) from the image-side surface 51 to the object-side surface 52 of the third lens 5 according to the eighth embodiment are shown.

Fig. 33 and 34 show relationships between important parameters in the optical eyepiece lens 10 according to the eighth embodiment.

Referring to fig. 30, it can be seen from the longitudinal spherical aberration diagrams of (a), (b), (c), and (d) that the optical performance of the eighth embodiment is also maintained.

Referring to fig. 33 and fig. 34, which are table diagrams of the optical parameters of the above eight preferred embodiments, when the relationship among the optical parameters in the optical eyepiece lens 10 of the present invention satisfies the following relationship, the optical performance still has better performance under the condition of shortened system length, so that when the present invention is applied to the related head-mounted display device, a thinner product can be manufactured:

(1) T3/G23 ≦ 71, BFL/G23 ≦ 105, and G23 are gaps between the second lens 4 and the third lens 5 on the optical axis I, and since the diopter of the cemented lens cemented by the first lens and the second lens and the diopter of the third lens are both positive, in order to obtain a larger magnification, i.e. a smaller system focal length, G23 needs to be reduced, but the existing processing and assembling process G23 cannot be reduced without limit, so that G23 is difficult to reduce, and therefore, the design of T3/G23 and BFL/G23 is preferably reduced. More preferably, 7.2 ≦ T3/G23 ≦ 71, and 7.5 ≦ BFL/G23 ≦ 105.

(2) T1/T2 ≧ 3.50, T12/T3 ≧ 0.75, ALT/T12 ≧ 1.70, ALT/TTL ≦ 0.70, BFL/T3 ≧ 1.00, BFL/TTL ≧ 0.30, as the requirements for imaging quality become higher and smaller, the length of the eyepiece lens 10 needs to be smaller and smaller, the surface shapes of the lenses in the vicinity of the optical axis I and the vicinity of the circumference often vary differently in consideration of the path of the light, the thickness of the center and the edge of the eyepiece lens 10 also vary, the light of the edge needs to be refracted by a larger angle inside the eyepiece lens 10 to be focused on the image source surface 100 in the vicinity of the optical axis I in consideration of the characteristics of the light, the thickness of the lenses and the air gaps need to be matched with each other to enable the eyepiece lens 10 to have good imaging quality, and the length and thickness of the eyepiece lens 10 and the optical axis I and the optical lens 10 and the optical axis I to be focused on the image source surface 100 The sizes of the gaps are all related, so that the thicknesses, gaps and focal lengths of the optical eyepiece lens 10 can be well configured when the relations are satisfied. Preferably, 3.50 ≦ T1/T2 ≦ 8.00, 0.75 ≦ T12/T3 ≦ 3.00, 1.35 ≦ ALT/T12 ≦ 2.30, 0.55 ≦ ALT/TTL ≦ 0.70, 1.00 ≦ BFL/T3 ≦ 3.00, 0.30 ≦ BFL/TTL ≦ 0.45.

In summary, the optical eyepiece lens 10 of the present invention can achieve the following effects and advantages, and thus the object of the present invention can be achieved:

firstly, by means of the high refractive index of the first lens 3 and the convex surfaces of the object side surface and the image side surface, the light angle can be effectively turned, and the optical eyepiece lens can be helped to condense light; the negative diopter of the second lens 4 is further matched, so that the excessively convergent peripheral field light rays can be effectively corrected, and the peripheral field is prevented from generating larger field curvature; and the material of the third lens 5 is plastic, which is beneficial to reducing the weight of the optical eyepiece lens 10 and reducing the cost.

Secondly, the image side surface 31 of the first lens 3 has a convex surface, so that the distance between the observation point and the lens on the optical axis can be greatly ensured to be larger than 20mm, and the experience feeling is effectively improved.

And a cemented lens cemented by the first lens 3 and the second lens 4, an aspheric surface of the image-side surface 51 of the third lens 5, and an aspheric surface of the object-side surface 52 of the third lens 5, which are mutually matched, contribute to correcting aberration and improve the imaging quality of the optical eyepiece lens 10.

The present invention makes the whole system have better capability of eliminating aberration, such as spherical aberration, by controlling the related design parameters, and then matches the concave-convex shape design and arrangement of the image side surfaces 31, 41, 51 or the object side surfaces 32, 42, 52 of the lenses 3, 4, 5, so that the optical eyepiece lens 10 still has the optical performance capable of effectively overcoming chromatic aberration under the condition of shortening the system length, and provides better imaging quality.

Fifth, the design of the optical eyepiece lens 10 of the present invention is shown by the descriptions of the above eight embodiments, and the system lengths of the above eight embodiments can be shortened to be less than 45mm, compared with the conventional optical eyepiece lens, the lens of the present invention can be applied to manufacture thinner products, so that the present invention has economic benefits meeting the market requirements.

The above embodiments are only used to further illustrate the optical eyepiece lens and the head-mounted display device of the present invention, but the present invention is not limited to the embodiments, and any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention fall within the protection scope of the technical solution of the present invention.

Claims

1. A head-mounted display device comprises a shell and a display module, and is characterized in that: the display module comprises an optical eyepiece lens and an image source display screen arranged at the object side of the optical eyepiece lens;

the optical eyepiece lens is composed of: the three lenses are respectively called a first lens, a second lens and a third lens, and the first lens, the second lens and the third lens respectively comprise an image side surface facing the observation side and allowing imaging light rays to pass through and an object side surface facing the image source side and allowing the imaging light rays to pass through;

Nd1=1.88，Nd2=1.94，Nd3=1.49；

Vd1=40.8，Vd2=17.9，Vd3=57.3；

1)0.93≤f1/f≤1.33；

2)1.45≤|f2/f|≤2.13；

3)1.19≤f3/f≤1.76；

wherein the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, and the system focal length is f;

the first lens and the third lens are positive lenses; the second lens is a negative lens;

the first lens is a biconvex lens; the second lens is a plano-concave lens; the third lens is an aspheric lens;

the aspheric expressions of the object side surface and the image side surface of the third lens are as follows:

wherein, Y is the distance between a point on the aspheric curve and the optical axis; z (Y) is the depth of the aspheric surface, i.e. the sag between the point on the aspheric surface at a distance Y from the optical axis and a tangent plane tangent to the vertex on the aspheric surface optical axisA straight distance; r is the radius of curvature of the lens surface; k is the cone coefficient; a is_2iIs aspheric coefficient of 2i order; n is a natural number, Y²ⁱIs the distance between a point on the 2 i-th order aspheric curve and the optical axis.