CN116755250A

CN116755250A - Optical system

Info

Publication number: CN116755250A
Application number: CN202310543987.0A
Authority: CN
Inventors: 陈必然; 朱能胜; 张梓轩; 张恒溢; 张振超
Original assignee: Huaqin Technology Co Ltd
Current assignee: Huaqin Technology Co Ltd
Priority date: 2023-05-15
Filing date: 2023-05-15
Publication date: 2023-09-15

Abstract

The invention discloses an optical system, which is applied to the technical field of virtual reality and is used for solving the problems of large volume and high weight of the optical system in the prior art. The optical system includes: the display screen, the first lens, the second lens and the third lens are sequentially arranged along the first direction, and the display screen further comprises a first polarizing film, a semi-transparent semi-reflective film and a second polarizing film which are sequentially arranged along the first direction; the semi-transparent semi-reflective film is arranged on a first surface of the first target lens, the second polarizing film is arranged on a second surface of the second target lens, and the first surface of the first target lens is different from the second surface of the second target lens; the first target lens and the second target lens are one or more of a first lens, a second lens, and a third lens; the first polarizing film is disposed on the display screen. The optical system reduces the thickness of each lens, thereby reducing the weight of the optical system, reducing the distance between each lens and effectively reducing the thickness of the optical system.

Description

Optical system

Technical Field

The invention relates to the field of Virtual Reality (VR), in particular to an optical system.

Background

Near-to-eye display devices have recently been developed with the breakthrough of software and hardware technologies. Taking a Virtual Reality (VR) head display as an example, the principle is that the left eye and the right eye of a user respectively see the content displayed on the display through the imaging lens on the VR head display, and the distance between the display and the imaging lens is within 1 time of the focal length, so that the user receives an upright virtual image amplified by the imaging lens. Because the magnification of the imaging lens can reach tens times or even hundreds times, the display content can form a hundred-inch-sized picture in human eyes after passing through the imaging lens.

At present, a display screen in a VR head display mainly comprises a liquid crystal (liquid crystal display, LCD) display screen and an organic light-emitting diode (OLED) display screen, and the two display screens are mature in technology, but have the defects of low pixel density, large volume, large power consumption, low contrast ratio and the like, and cannot completely meet the requirements of the VR head display on the display screen.

In summary, there is a need for an optical system to solve the problems of large size and high weight of the optical system in the prior art.

Disclosure of Invention

The embodiment of the invention provides an optical system which is used for solving the problems of large volume and high weight of the optical system in the prior art.

In a first aspect, an embodiment of the present invention provides an optical system including: the display screen, the first lens, the second lens and the third lens are sequentially arranged along the first direction, and the display screen further comprises a first polarizing film, a semi-transparent semi-reflective film and a second polarizing film which are sequentially arranged along the first direction; the transmission surface of the semi-transparent semi-reflective film is opposite to the first polarizing film, and the reflection surface of the semi-transparent semi-reflective film is opposite to the second polarizing film; the semi-transparent semi-reflective film is arranged on a first surface of the first target lens, the second polarizing film is arranged on a second surface of the second target lens, and the first surface of the first target lens is different from the second surface of the second target lens; the first target lens and the second target lens are one or more of a first lens, a second lens, and a third lens; the first polarizing film is arranged on the display screen and is used for converting light rays emitted by the display screen into circular polarized light; the second polarizing film is used for reflecting the circularly polarized light from the first polarizing film and converting the circularly polarized light from the semi-transparent and semi-reflective film into linearly polarized light and transmitting the linearly polarized light out.

In the embodiment of the invention, as the optical system is provided with the plurality of lenses (namely the first lens, the second lens and the third lens), and the first polarizing film, the semi-transparent semi-reflective film and the second polarizing film which are sequentially arranged along the first direction, light rays emitted by the display screen can be folded back among the plurality of lenses for a plurality of times, and the light path is folded layer by layer, so that imaging is realized. Further, in order to meet the magnification requirement of the optical system, the thickness of the lens is thicker, however, in the scheme, due to the fact that the three lenses are arranged, light rays emitted by the display screen can be folded back among the three lenses for multiple times, so that the magnification requirement of the optical system can be met even if the thickness of each lens in the optical system is reduced, the thickness of each lens is reduced by the aid of the three lenses, weight of the optical system is reduced, meanwhile, distance among the lenses is reduced, and thickness of the optical system is effectively reduced.

Alternatively, the display screen is a micro oled with a resolution of 3500×3800 and a size of 1.3 inches.

In the embodiment of the invention, most of the current display screens for VR head display can only enable the VR head display to reach about 20PP, which can not meet the requirement of human eyes, and as the resolution of the micro OLED display screen is 3500 multiplied by 3800, compared with the traditional display screen with lower resolution, more pixels can be provided in unit area, so that more details and clearer images can be displayed, the VR head display can reach 40PPD, the definition and color accuracy of the system are improved, and the problem of low pixel density of the optical system in the prior art is solved. In addition, the 1.3 inch display screen is of moderate size so that sufficient information can be displayed on the screen on the basis of being embedded in a smaller optical system.

Optionally, the first polarizing film includes a linear polarizer, a first quarter-wave plate; the linear polarizer is attached to the display screen, and the first quarter-wave plate is attached to the linear polarizer.

In the embodiment of the invention, the light emitted by the display is converted into circular polarized light by arranging the linear polaroid and the first quarter wave plate.

Optionally, the second polarizing film includes a second quarter wave plate and a polarizing reflector.

In the embodiment of the invention, the second quarter wave plate and the polarizing reflecting plate are arranged in the second polarizing film, so that the circularly polarized light from the first polarizing film can be reflected, and the circularly polarized light from the semi-transparent semi-reflective film is converted into linearly polarized light and then transmitted out.

Optionally, the second target lens is a second lens, a second surface of the second target lens is a surface of the second lens opposite to the third lens, the second quarter wave plate is attached to the second lens, and the polarizing reflector is attached to the second quarter wave plate.

Optionally, the second target lens is a third lens, the second surface of the second target lens is a surface of the third lens opposite to the second lens, the polarizing reflector is attached to the third lens, and the second quarter wave plate is attached to the polarizing reflector.

Optionally, the thickness L1 of the third lens is in the range of [4mm,7mm ], the radius of curvature R1 of the side of the third lens close to the user is in the range of [40mm,500mm ], and the radius of curvature R2 of the side of the third lens close to the display screen is in the range of [ -25mm, -150mm ].

In the embodiment of the invention, the thickness of the third lens is set between 4mm and 7mm, so that the weight of the whole optical system can be reduced on the basis of meeting the magnification requirement of the optical system. By setting the radius of curvature of the third lens within a reasonable parameter range, it is helpful to improve the sharpness, contrast, and wider angle field of view of the optical system.

Optionally, the thickness L2 of the second lens ranges from [2mm,7mm ], the radius of curvature R3 of the side of the second lens close to the user ranges from [ -100mm,300mm ], and the radius of curvature R4 of the side of the second lens close to the display screen ranges from [ -25mm,300mm ].

In the embodiment of the invention, the thickness of the second lens is set between 2mm and 7mm, so that the weight of the whole optical system can be reduced on the basis of meeting the magnification requirement of the optical system. By setting the radius of curvature of the second lens within a reasonable parameter range, it is helpful to improve the sharpness, contrast, and wider angle field of view of the optical system.

Optionally, the thickness L3 of the first lens ranges from 2mm,8mm, the radius of curvature R1 of the side of the first lens close to the user ranges from-100 mm,400mm, and the radius of curvature R2 of the side of the first lens close to the display screen ranges from-200 mm, -40 mm.

In the embodiment of the invention, the thickness of the first lens is set between 2mm and 8mm, so that the weight of the whole optical system can be reduced on the basis of meeting the magnification requirement of the optical system. By setting the radius of curvature of the first lens within a reasonable parameter range, it is helpful to improve the sharpness, contrast, and wider angle field of view of the optical system.

Alternatively, the total length of the optical system may range from [18mm,20mm ].

In the embodiment of the invention, the range of the total length L of the optical system is set between 18mm and 20mm, so that the optical system is facilitated to provide a clearer image, and meanwhile, the optical system with the total length range is light and comfortable, so that the uncomfortable feeling of a user in the wearing process is reduced.

Drawings

In order to more clearly illustrate the technical solutions of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an optical system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a first polarizing film according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a second polarizing film according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a second polarizing film according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an optical system according to an embodiment of the present invention;

FIG. 6 is a full field MTF diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 7 is a field curvature diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 8 is a distortion chart of an optical system with an entrance pupil at the center provided by an embodiment of the present invention;

FIG. 9 is a point diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 10 is a full field MTF diagram of an optical system with an entrance pupil at the Eye box edge provided by an embodiment of the present invention;

FIG. 11 is a field curvature diagram of an optical system with an entrance pupil at the Eye box edge according to an embodiment of the present invention;

FIG. 12 is a diagram showing the distortion of an optical system when the entrance pupil is at the Eye box edge according to an embodiment of the present invention;

FIG. 13 is a point diagram of an optical system with an entrance pupil at the Eye box edge according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of an optical system according to an embodiment of the present invention;

FIG. 15 is a full field MTF diagram of an optical system with an entrance pupil centered according to an embodiment of the present invention;

FIG. 16 is a field curvature diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 17 is a diagram showing distortion of an optical system with an entrance pupil centered according to an embodiment of the present invention;

FIG. 18 is a point diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 19 is a full field MTF diagram of an optical system with an entrance pupil at the Eye box edge provided by an embodiment of the present invention;

FIG. 20 is a field curvature diagram of an optical system with an entrance pupil at the Eye box edge according to an embodiment of the present invention;

FIG. 21 is a diagram showing the distortion of an optical system when the entrance pupil is at the Eye box edge according to an embodiment of the present invention;

FIG. 22 is a point diagram of an optical system with an entrance pupil at the Eye box edge according to an embodiment of the present invention;

FIG. 23 is a schematic diagram of an optical system according to an embodiment of the present invention;

FIG. 24 is a full field MTF diagram of an optical system with an entrance pupil centered, according to an embodiment of the present invention;

FIG. 25 is a field curvature diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 26 is a diagram showing distortion of an optical system with an entrance pupil centered according to an embodiment of the present invention;

FIG. 27 is a point diagram of an optical system with an entrance pupil at the center, according to an embodiment of the present invention;

FIG. 28 is a full field MTF diagram of an optical system with an entrance pupil at the Eye box edge provided by an embodiment of the present invention;

FIG. 29 is a field curvature diagram of an optical system with an entrance pupil at the Eye box edge according to an embodiment of the present invention;

FIG. 30 is a diagram showing the distortion of an optical system when the entrance pupil is at the Eye box edge, according to an embodiment of the present invention;

fig. 31 is a point chart of an optical system with an entrance pupil at the Eye box edge according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Fig. 1 is a schematic structural diagram of an optical system according to an embodiment of the present invention. As shown in fig. 1, the optical system 100 includes: the display panel 101, the first lens 102, the second lens 103, and the third lens 104, which are sequentially disposed along the first direction, further include a first polarizing film 105, a half-transmissive film 106, and a second polarizing film 107, which are sequentially disposed along the first direction. Each of the components is described in detail below:

the display screen 101 is used to emit light to display an image.

The first lens 102, the second lens 103, and the third lens 104 are respectively configured to transmit light emitted from the display screen 101, thereby magnifying an image displayed on the display screen 101.

The first polarizing film 105 is disposed on the display screen 101, and is used for converting light emitted from the display screen 101 into circular polarized light.

The semi-transparent and semi-reflective film 106 is disposed on a first surface of a first target lens, which is one of a first lens, a second lens, and a third lens; in the example of fig. 1, the first target lens is a first lens 102, and the first surface of the first target lens is a surface of the first lens 102 opposite to the display screen 101. The transmissive surface of the transflective film 106 is opposite to the first polarizing film 105, and the reflective surface of the transflective film 106 is opposite to the second polarizing film 107. In another possible embodiment, the first target lens is the first lens 102, and the first surface of the first target lens is the surface of the first lens 102 opposite to the second lens 103.

The second polarizing film 107 is disposed on a second face of a second target lens, which is one of the first lens, the second lens, and the third lens; the first target lens and the second target lens may refer to the same lens, or may refer to two different lenses, and the first surface of the first target lens is different from the second surface of the second target lens. In the example of fig. 1, the second target lens is the second lens 103, and the second face of the second target lens is the face of the second lens 103 opposite the third lens 104. The second polarizing film 107 is used to reflect the circularly polarized light from the first polarizing film 105, and also to convert the circularly polarized light from the transflective film 106 into linearly polarized light and transmit the linearly polarized light.

The display 101, the first lens 102, the second lens 103, and the third lens 104 are sequentially disposed along a first direction, and the first polarizing film 105, the half-transmissive film 106, and the second polarizing film 107 are sequentially disposed along the first direction, which may be a left-to-right direction or a right-to-left direction, which is not particularly limited in this regard, and in the example of fig. 1, the first direction is a right-to-left direction.

Taking the optical system illustrated in fig. 1 as an example, the imaging principle of the optical system 100 will be described below:

the display screen 101 emits a first light to the first polarizing film 105, and the first polarizing film 105 converts the first light into a first circularly polarized light and transmits the first circularly polarized light to the transflective film 106; the transflective film 106 transmits the first circularly polarized light to the first lens 102; the first lens 102 transmits the first circularly polarized light to the second lens 103; the second lens 103 transmits the first circularly polarized light to the second polarizing film 107; the second polarizing film 107 converts the first circularly polarized light into second circularly polarized light and reflects the second circularly polarized light to the second lens 103; then, the second lens 103 transmits the second circularly polarized light to the first lens 102; the first lens 102 transmits the second circularly polarized light to the transflective film 106; the transflective film 106 reflects the second circularly polarized light to the first lens 102; the first lens 102 transmits the second circularly polarized light to the second lens 103; the second lens 103 transmits the second circularly polarized light to the second polarizing film 107; the second polarizing film 107 converts the second circularly polarized light into first linearly polarized light and transmits the first linearly polarized light to the third lens 104; the third lens 104 transmits the first linear polarized light to the human eye.

In one possible implementation, the display screen is a micro oled with a resolution of 3500 x 3800 and a size of 1.3 inches.

In detail, micro OLED, also called silicon-based OLED, is different from conventional LCD and OLED in that glass is used as a substrate, and the substrate of micro OLED is a monocrystalline silicon wafer, so that a self-luminous display with thinner thickness, lower power consumption and high luminous efficiency can be produced; in addition, the pixels of the micro OLED display screen are 1/10 of those of the traditional display screen (such as an LCD display screen), so the micro OLED display screen has higher pixel density (PPI); in addition, the micro OLED display screen still has OLED characteristics, can provide high-brightness, high-contrast and high-vividness color display, and thus, high-quality images are generated; in addition, the response time of the micro OLED display screen approaches zero, so that high brushing can be realized to improve the image quality effect; the power consumption of the micro OLED display screen is low, so that the service life of a battery can be prolonged, and the maintenance cost of a system can be reduced; in addition, the micro OLED display screen has the advantages of being lighter, thinner, shorter, smaller, high in luminous efficiency and the like.

In one possible implementation, the first polarizing film includes a linear polarizer, a first quarter-wave plate. The linear polarizer is attached to the display screen, and the first quarter-wave plate is attached to the linear polarizer.

As shown in fig. 2, a schematic structural diagram of a first polarizing film according to an embodiment of the present invention is provided. In fig. 2, the first polarizing film 105 includes a linear polarizer 1051, a first quarter wave plate 1052; a linear polarizer 1051 is attached to the display 101, and a first quarter wave plate 1052 is attached to the linear polarizer 1051.

Wherein the linear polarizer 1051 is made of a dichroic material, and can selectively reflect or transmit light having a specific polarization direction for polarization.

The first quarter wave plate 1052 refers to a thin film material having special optical properties that can change the polarization state of light, for example, convert linearly polarized light into circularly polarized light or convert circularly polarized light into linearly polarized light.

In one possible implementation, the second polarizing film includes a second quarter wave plate and a polarizing reflector.

As shown in fig. 3, a schematic structural diagram of a second polarizing film according to an embodiment of the present invention is provided. In fig. 3, the second polarizing film 107 includes a second quarter-wave plate 1071 and a polarizing reflector 1072.

The second quarter wave plate 1071 is a thin film material with special optical properties, and can change the polarization state of light, for example, convert linear polarized light into circular polarized light or convert circular polarized light into linear polarized light.

The polarizing reflector 1072 may selectively reflect or transmit light having a specific polarization direction, and may reflect light not belonging to the specific polarization direction, for example, the linear polarizer 1051 may transmit P light and reflect S light, and for example, the linear polarizer 1051 may transmit S light and reflect P light.

In the embodiment of the present invention, by disposing the second quarter wave plate and the polarizing reflection plate in the second polarizing film, the circularly polarized light from the first polarizing film 105 can be reflected, and the circularly polarized light from the semi-transparent semi-reflective film 106 is further converted into linearly polarized light and transmitted.

It should be noted that, the position of the second polarizing film is not particularly limited in the embodiment of the present invention, for example, the second polarizing film 107 may be located on a side of the second lens 103 opposite to the third lens 104 (as shown in fig. 3), and the second polarizing film 107 may also be located on a side of the third lens 104 opposite to the second lens 103 (as shown in fig. 4).

In one possible implementation, the second target lens is the second lens 103, the second surface of the second target lens is the surface of the second lens 103 opposite to the third lens 104, the second quarter wave plate 1071 is attached to the second lens 103, and the polarizing reflector 1072 is attached to the second quarter wave plate 1071.

As shown in fig. 4, a schematic structural diagram of a second polarizing film according to an embodiment of the present invention is provided. In one possible implementation, the second target lens is the third lens 104, the second surface of the second target lens is the surface of the third lens 104 opposite to the second lens, the polarizing reflector 1072 is attached to the third lens 104, and the second quarter wave plate 1071 is attached to the polarizing reflector.

In one possible implementation, the thickness L1 of the third lens ranges from [4mm,7mm ], the radius of curvature R1 of the face of the third lens closest to the user ranges from [40mm,500mm ], and the radius of curvature R2 of the face of the third lens closest to the display screen ranges from [ -25mm, -150mm ].

The radius of curvature is a physical quantity describing the degree of curvature of a lens or curved surface, and is used to represent the radius of a circle forming the lens or curved surface, that is, the curvature of the lens or curved surface. Specifically, when the lens or curved surface assumes an outwardly convex shape, the radius of curvature thereof is positive; when the lens or curved surface assumes an inwardly convex shape, its radius of curvature is negative. In an optical system, the radius of curvature of a lens determines the focusing and deflecting effects of the lens on light rays, and thus has an important influence on the imaging performance and optical quality of the lens. The smaller the radius of curvature of the lens, the greater the curvature of the lens and the greater the imaging capability.

Illustratively, in one possible implementation, the thickness L1 of the third lens is 7.47mm, the radius of curvature R1 of the side of the third lens adjacent to the user is 336.35mm, and the radius of curvature R2 of the side of the third lens adjacent to the display screen ranges from-66.23 mm.

In one possible implementation, the thickness L2 of the second lens ranges from 2mm,7mm, the radius of curvature R3 of the side of the second lens close to the user ranges from-100 mm,300mm, and the radius of curvature R4 of the side of the second lens close to the display screen ranges from-25 mm,300 mm.

Illustratively, in one possible implementation, the thickness L2 of the second lens is 2.75mm, the radius of curvature R3 of the side of the second lens adjacent to the user is-181, and the radius of curvature R4 of the side of the second lens adjacent to the display screen is 170mm.

In one possible implementation, the thickness L3 of the first lens ranges from 2mm,8mm, the radius of curvature R5 of the side of the first lens closest to the user ranges from-100 mm,400mm, and the radius of curvature R6 of the side of the first lens closest to the display screen ranges from-200 mm, -40 mm.

Illustratively, in one possible implementation, the thickness L3 of the first lens is 6.54mm, the radius of curvature R5 of the side of the first lens adjacent to the user is 468, and the radius of curvature R6 of the side of the first lens adjacent to the display screen ranges from-32 mm.

In one possible implementation, the total length of the optical system is in the range of [18mm,20mm ].

Illustratively, in one possible implementation, the total length of the optical system is in the range of 18mm.

In one possible implementation, the material of the lenses of the optical system is APL series, and/or EP series, and/or Optimas series.

In order to make the schemes of the embodiments of the present invention clearer, specific implementations of several optical systems provided by the embodiments of the present invention are described below.

Embodiment one:

as shown in fig. 5, a schematic structural diagram of an optical system according to an embodiment of the present invention is provided. The optical system includes: a display screen, a first polarizing film, a semi-transparent and semi-reflective film, a first lens, a second polarizing film, and a third lens disposed in this order from right to left; the semi-transparent and semi-reflective film is disposed on a side of the first lens 102 opposite to the display screen, and the second polarizing film is disposed on a side of the second lens 103 opposite to the third lens 104.

Wherein the material of the first lens is APL5514, the material of the second lens is EP7000, and the material of the third lens is APL5514.

In the present embodiment, the entrance pupil diameter of the optical system is 4mm, the eye movement range (eye box) is set to 8mm, and the wavelength of light emitted from the display 101 is set to 0.486um, 0.588um, 0.656um; the distance (i.e., eye distance) from the geometric center of the optical axis where the pupil is located to the third lens is set to 15mm. The maximum field angle of the optical system is 80 °.

In the present embodiment, in the optical system, aspherical surface type coefficients of the first lens, the second lens, and the third lens are shown in table 1 below, where A1 represents a surface on the third lens entrance pupil side, B1 represents a surface on the third lens screen side, C1 represents a surface on the second lens screen side, D1 represents a surface on the first lens entrance pupil side, and E1 represents a surface on the first lens screen side;

TABLE 1 aspherical surface coefficients

	Coefficient of taper	Item of 4 th order	6 th order item	8 th order item
					A1	-99.66	-2.18E-05	-7.90E-10	2.29E-10
B1	-6.02	-4.97E-05	1.00E-07	8.75E-11
					C1	63.82	3.61E-05	-1.48E-07	1.70E-10
D1	-41.32	4.18E-05	-1.39E-07	1.25E-10
					E1	5.37	3.81E-06	-3.33E-09	1.86E-12

The optical system can achieve a better imaging effect, and can be specifically represented by a point column diagram, a modulation transfer function (Modulation Transfer Function, MTF) curve diagram, a distortion diagram and a field curvature diagram. The MTF graph is a graph that describes the imaging capabilities of an imaging system. In imaging systems, light rays are subject to various effects, such as scattering, dispersion, optical distortion, and the like, as they pass through lenses and other optical elements. These effects can reduce the resolution and contrast of the imaging system. The MTF graph describes the capabilities of the optical system to deliver blur or contrast loss at different frequencies, demonstrating the capabilities of the imaging system when imaging light of different frequencies.

FIG. 6 shows a full field MTF diagram of an optical system with an entrance pupil centered; FIG. 7 shows a field curvature of an optical system with an entrance pupil centered; FIG. 8 shows a distortion map of an optical system with an entrance pupil centered; FIG. 9 shows a point column diagram of an optical system with an entrance pupil in the center; FIG. 10 shows a full field MTF diagram of an optical system with an entrance pupil at the Eye box edge; FIG. 11 shows a field curvature of an optical system with an entrance pupil at the Eye box edge; FIG. 12 shows a distortion plot of an optical system with an entrance pupil at the Eye box edge; fig. 13 shows a point column diagram of the optical system with the entrance pupil at the Eye box edge.

Embodiment two:

as shown in fig. 14, a schematic structural diagram of an optical system according to an embodiment of the present invention is provided. The optical system includes: a display screen, a first polarizing film, a semi-transparent and semi-reflective film, a first lens, a second polarizing film, and a third lens disposed in this order from right to left; the semi-transparent and semi-reflective film is disposed on a side of the first lens 102 opposite to the display screen, and the second polarizing film is disposed on a side of the third lens 104 opposite to the second lens 103.

Wherein the material of the first lens is APL5514, the material of the second lens is EP6000, and the material of the third lens is APL5514.

In the present embodiment, the entrance pupil diameter of the optical system is 4mm, the eye movement range (eye box) is set to 8mm, and the wavelength of light emitted from the display 101 is set to 0.486um, 0.588um, 0.656um; the distance (i.e., eye distance) from the geometric center of the optical axis where the pupil is located to the third lens is set to 15mm. The maximum field angle of the optical system is 70 °.

In the present embodiment, in the optical system, aspherical surface type coefficients of the first lens, the second lens, and the third lens are shown in table 2 below, where A2 represents a surface on the third lens entrance pupil side, B2 represents a surface on the second lens entrance pupil side, C2 represents a surface on the second lens screen side, D2 represents a surface on the first lens entrance pupil side, and E2 represents a surface on the first lens screen side.

TABLE 2 aspherical surface coefficients

Coefficient of taper

Item of 4 th order

6 th order item

8 th order item

Item of order 10

12 th order item

A2

5.40

-3.20E-06

1.85E-08

-3.01E-10

8.90E-13

-1.30E-15

B2

60.27

8.44E-07

7.25E-09

-2.08E-12

3.62E-13

-8.77E-16

C2

80.45

1.09E-05

-1.27E-08

-1.03E-11

-4.15E-13

8.16E-16

D2

-0.32

4.10E-06

-6.13E-09

-2.63E-11

4.16E-14

-7.05E-16

E2

-0.22

-7.89E-07

-5.36E-10

3.09E-11

1.75E-14

-3.32E-16

The optical system can achieve a better imaging effect, and fig. 15 shows a full-field MTF diagram of the optical system with the entrance pupil at the center; FIG. 16 shows a field curvature of an optical system with an entrance pupil centered; FIG. 17 shows a distortion plot of an optical system with an entrance pupil centered; FIG. 18 shows a point column diagram of an optical system with an entrance pupil in the center; FIG. 19 shows a full field MTF diagram of an optical system with an entrance pupil at the Eye box edge; FIG. 20 shows a field curvature of an optical system with an entrance pupil at the Eye box edge; FIG. 21 shows a distortion plot of an optical system with an entrance pupil at the Eye box edge; fig. 22 shows a point column diagram of an optical system with an entrance pupil at the Eye box edge.

Embodiment III:

as shown in fig. 23, a schematic structural diagram of an optical system according to an embodiment of the present invention is provided. The optical system includes: a display screen, a first polarizing film, a semi-transparent and semi-reflective film, a first lens, a second polarizing film, and a third lens disposed in this order from right to left; the semi-transparent and semi-reflective film is disposed on a side of the first lens 102 opposite to the display screen, and the second polarizing film is disposed on a side of the third lens 104 opposite to the second lens 103.

Wherein the material of the first lens is EP6000, the material of the second lens is Optimas7500, and the material of the third lens is APL5014.

In the present embodiment, the entrance pupil diameter of the optical system is 4mm, the eye movement range (eye box) is set to 10mm, and the wavelength of light emitted from the display 101 is set to 0.486um, 0.588um, 0.656um; the distance (i.e., eye distance) from the geometric center of the optical axis where the pupil is located to the third lens is set to 15mm. The maximum field angle of the optical system is 66 °.

In the present embodiment, in the optical system, aspherical surface type coefficients of the first lens, the second lens, and the third lens are shown in table 3 below, where A3 denotes a surface on the third lens entrance pupil side, B3 denotes a surface on the second lens entrance pupil side, C3 denotes a surface on the second lens panel side, D3 denotes a surface on the first lens entrance pupil side, and E3 denotes a surface on the first lens panel side.

TABLE 3 aspherical surface coefficients

The optical system can achieve better imaging effect, and fig. 24 shows a full field MTF diagram of the optical system with the entrance pupil at the center; FIG. 25 shows a field curvature of an optical system with an entrance pupil centered; FIG. 26 shows a distortion map of an optical system with an entrance pupil centered; FIG. 27 shows a point column diagram of an optical system with an entrance pupil in the center; FIG. 28 shows a full field MTF diagram of an optical system with an entrance pupil at the Eye box edge; FIG. 29 shows a field curvature of an optical system with an entrance pupil at the Eye box edge; FIG. 30 shows a distortion plot of an optical system with an entrance pupil at the Eye box edge; fig. 31 shows a point chart of the optical system with the entrance pupil at the Eye box edge.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiments of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the invention. Thus, the embodiments of the present invention are intended to include such modifications and alterations insofar as they come within the scope of the embodiments of the invention as claimed and the equivalents thereof.

Claims

1. An optical system, the optical system comprising: the display screen, the first lens, the second lens and the third lens are sequentially arranged along the first direction, and the display screen further comprises a first polarizing film, a semi-transparent semi-reflective film and a second polarizing film which are sequentially arranged along the first direction; the transmission surface of the semi-transparent and semi-reflective film is opposite to the first polarization film, and the reflection surface of the semi-transparent and semi-reflective film is opposite to the second polarization film;

the semi-transparent and semi-reflective film is arranged on a first surface of a first target lens, the second polarizing film is arranged on a second surface of a second target lens, and the first surface of the first target lens is different from the second surface of the second target lens; the first target lens and the second target lens are one or more of a first lens, a second lens, and a third lens;

the first polarizing film is arranged on the display screen and is used for converting light rays emitted by the display screen into circular polarized light; the second polarizing film is used for reflecting the circularly polarized light from the first polarizing film and converting the circularly polarized light from the semi-transparent semi-reflective film into linearly polarized light and transmitting the linearly polarized light out.

2. The optical system of claim 1, wherein the display screen is a micro oled having a resolution of 3500 x 3800 and a size of 1.3 inches.

3. The optical system of claim 1, wherein the first polarizing film comprises a linear polarizer, a first quarter wave plate; the linear polarizer is attached to the display screen, and the first quarter wave plate is attached to the linear polarizer.

4. The optical system of claim 1, wherein the second polarizing film comprises a second quarter wave plate and a polarizing reflector.

5. The optical system of claim 4, wherein the second target lens is the second lens, the second face of the second target lens is the face of the second lens opposite the third lens, the second quarter wave plate is attached to the second lens, and the polarizing reflector is attached to the second quarter wave plate.

6. The optical system of claim 4, wherein the second target lens is a third lens, the second face of the second target lens is a face of the third lens opposite the second lens, the polarizing reflector is attached to the third lens, and the second quarter wave plate is attached to the polarizing reflector.

7. An optical system as claimed in claim 1, characterized in that the thickness L1 of the third lens ranges from [4mm,7mm ], the radius of curvature R1 of the side of the third lens close to the user ranges from [40mm,500mm ], and the radius of curvature R2 of the side of the third lens close to the display screen ranges from [ -25mm, -150mm ].

8. An optical system as claimed in claim 1, characterized in that the thickness L2 of the second lens ranges from 2mm,7mm, the radius of curvature R3 of the side of the second lens close to the user ranges from-100 mm,300mm, and the radius of curvature R4 of the side of the second lens close to the display screen ranges from-25 mm,300 mm.

9. An optical system as claimed in claim 1, characterized in that the thickness L3 of the first lens ranges from [2mm,8mm ], the radius of curvature R1 of the side of the first lens close to the user ranges from [ -100mm,400mm ], and the radius of curvature R2 of the side of the first lens close to the display screen ranges from [ -200mm, -40mm ].

10. The optical system of claim 1, wherein the total length of the optical system ranges from [18mm,20mm ].