Optical device, optical system, and optical apparatus

Abstract

The invention relates to the field of optical devices, and provides an optical device, an optical system and optical equipment, and the optical device comprises a first device and a second device. The first device comprises one or more first-class surfaces and second-class surfaces, and the second device comprises the first-class surface opposite to the second-class surface of the first device; the first type of light and the second type of light are incident and / or emergent from the first type of surface, and the first type of light and the second type of light form different angles with the first type of surface and / or the second type of surface; the first type of light and at least part of the second type of light are transmitted in the first device and then enter the second type of surface of the first device; the first type of light is emitted and / or incident from the second type of surface of the first device, and at least part of the second type of light incident on the second type of surface of the first device is reflected by the second type of surface. According to the invention, light with angles different from those of effective light rays is filtered out in an angle distinguishing mode, and in some applications, the system size can be further reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical devices, in particular, to an optical device, an optical system and an optical equipment. BACKGROUND

[0002] Stray light is the non-expected light in the optical system, also known as optical "noise", which is caused by various reasons. In optical applications, stray light is an important factor affecting the performance of the system. With the increasing demand for optical system detection, the requirement for analyzing and suppressing stray light is also increasing.

[0003] Especially for optical systems with internal reflection, such as PANCAKE lens groups and waveguide systems, due to multiple reflections of light in the device, stray light often mixes with the required light, and it is difficult to remove stray light using traditional techniques, which often causes ghosting and other problems in imaging applications, seriously affecting product use. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide an optical device, an optical system and an optical equipment.

[0005] According to the present application, an optical device is provided, comprising: a first device and a second device;

[0006] The first device comprises one or more first type surfaces and one or more second type surfaces, and the first type surfaces and the second type surfaces on the same first device are not parallel;

[0007] The second device comprises a first type surface opposite to the second type surface of the first device;

[0008] There is a gap between the second type surface of the first device and the first type surface of the second device;

[0009] The first type light and the second type light are incident and / or emitted from the first type surface to the optical device, and the angle between the first type light and the first type surface is different from the angle between the second type light and the first type surface, and / or the angle between the first type light and the second type surface is different from the angle between the second type light and the second type surface;

[0010] After the first type surface, at least part of the first type light and at least part of the second type light propagate in the first device (direct propagation, here refers to the light after passing the first type surface, as the first type light and the second type light, which do not pass other surfaces in the first device, for example, after passing the first type surface once, they do not pass other surfaces before reaching the second surface, but before passing the first type surface, they can pass multiple surfaces in the first device multiple times, and the passing refers to the transmission or reflection on the above surfaces) to the second type surface of the first device (such as entering the first device by the first type surface, or according to the optical path reversibility principle, it can also be from the second type surface to the first type surface and then exit the first device. Or it can also be reflected after entering the second type surface, or it can also be reflected after propagating from the second type surface to the first type surface).

[0011] The angle between the first type surface and the second type surface of the first device satisfies the following conditions:

[0012] At least part of the first type light exits and / or enters from the second type surface of the first device (transmits from the second type surface, for example, the light has a 95% transmission rate without an antireflection film), and at least part of the second type light is reflected by the second type surface of the first device (for example, the second type light entering the second type surface is fully reflected or more than 90% is reflected). Or at least part of the first type light is reflected by the second type surface of the first device, and at least part of the second type light is transmitted from the second type surface of the first device.

[0013] Preferably, the first type surface and the second type surface satisfy the following relationship (for example Figure 4 As shown, the surfaces are all planes, the angle 103 between the first type surface 101 and the second type surface 102 is θ, the angle between the first type light 41 and the normal of the surface 101 when entering is in the range [Ω, Φ] (in this example, the clockwise direction is defined as - and the counterclockwise direction is defined as +), the angle between the second type light 42 and the normal of the surface 101 when entering is greater than or equal to α (α ≥ Φ, or it can also be set to be greater than or equal to α or less than or equal to β and β ≤ Ω, and the range of θ is adjusted accordingly), the refractive index of the first device 101 is n1, the refractive index of the external medium is n0, and the refractive index of the medium in the gap 312 between the surface 102 of the first device and the surface 201 of the second device is n3 (if it is air, n3 = 1), then θ satisfies the condition: Similarly, the relationship between θ and the lower limit angle Ω of the first type light and the limited angle β of the second type light can also be derived.

[0014] Preferably, the first type of light and the second type of light experience the same optical process on the first type of surface, such as reflection, transmission, etc. For example, both the first type of light and the second type of light are transmitted (both exit / enter, or one exits and the other enters), or both are reflected. The first type of light and the second type of light experience different optical processes on the second type of surface, such as the first type of light is transmitted and the second type of light is reflected, or the first type of light is reflected and the second type of light is transmitted.

[0015] Preferably, after the second type of light is reflected, at least a portion of the second type of light is coupled out of the optical device or is absorbed (e.g., by an absorbing layer). Alternatively, after the first type of light is transmitted through the second type of surface, at least a portion of the first type of light is coupled out of the optical device or is absorbed.

[0016] After the second type of light 42 is reflected, at least a portion of the second type of light is coupled out of the optical device or is absorbed, i.e., the light that is coupled out of the optical device or is absorbed is filtered out as stray light (e.g., as shown in Figure 1 After the first type of light 41 is transmitted through the second type of surface 102, at least a portion of the first type of light is coupled out of the optical device or is absorbed (e.g., in the second device 20 or out of the system, or the second device 20 itself is an absorbing device, or there can be no second device in some cases). In this case, the first type of light 41 is filtered out as stray light, and the second type of light 42 is used as useful light. In this case, the second type of light can be further processed by other devices.

[0017] Preferably, after the first type of light is transmitted through the second type of surface, the first type of light is coupled into the second device through a first type of surface on the second device. The first and second devices can be opposite, e.g., in an optical system, some devices are second devices for the previous stage and are first devices for the next stage.

[0018] Preferably, the second device includes one or more of the following: a lens, a prism, a mirror, a half mirror, a waveguide, an optical fiber, an optical rod, a reflective bowl, an absorbing device, a lens array, a prism array, a grating, a spatial light modulator, an optical fiber, an absorbing device (e.g., black tape or frosted surface), etc. The second device can also be a combination of the above devices, e.g., a prism, a waveguide, and a half mirror are combined by gluing or bonding to form a single device. The waveguide can include at least two surfaces between which light undergoes at least one total internal reflection. The two surfaces of the waveguide can be parallel or non-parallel (e.g., a triangular or wedge-shaped waveguide, in which the angle of incidence changes after each total internal reflection). The surfaces of the waveguide can be planar or curved.

[0019] Preferably, the first device has a cross-section that is triangular, wedge-shaped, polygonal, or has a curved shape. For example,Figure 1 、 Figure 2 、 Figure 3 As shown in FIG. 1, the cross section of the first device 10 is triangular or wedge-shaped, or can also be an irregular polygon or a curved shape as shown in FIG. 2. Figure 4 、 Figure 5 As shown in FIG. 1, the cross section of the first device 10 is triangular or wedge-shaped, or can also be an irregular polygon or a curved shape as shown in FIG. 2.

[0020] Preferably, the surface of one or more of the first type of surface and the second type of surface of the optical device is prepared with one or more functional film layers. For example, a film with different transmittance for light at different angles (e.g., light at an angle of less than 30° has a transmittance of >95%, and light at an angle of more than 40° has a transmittance of <5%), a polarized reflection film, a wave plate, a semi-transmission and semi-reflection film with a certain transmission and reflection ratio, an anti-reflection film layer, a wavelength-dependent transmittance / reflection film, a micro-prism array (e.g., a micro-prism array similar to a privacy film), a micro-lens array, a grating film, etc.

[0021] Preferably, the number of the first devices and / or the second devices is multiple. For example, an optical device contains 4 first devices and 2 second devices.

[0022] Preferably, there is a gap between the surfaces of the multiple first devices and / or second devices. The gap can be an air gap or a gap filled with a film.

[0023] Preferably, the first type of light is converted into the second type of light after passing through the first type of surface, and / or the second type of light is converted into the first type of light after passing through the first type of surface. For example, as shown in FIG. 4, the light 411 is converted into the second type of light 421 after passing through the first type of surface 1010 for the second time (reflected). Figure 6

[0024] According to the present application, an optical system is provided, which comprises the optical device.

[0025] According to the present application, an optical device is provided, which comprises the optical device.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The present application can effectively filter out light with different angles from the effective light by angle discrimination, and can well solve the problem of stray light. In some applications, the present application can also reduce the size of the device / system. According to the principle of optical path reversibility, the emission and incidence in the present application are relatively reversible (emission to incidence, and incidence to emission), and the definition of the device is also relative. BRIEF DESCRIPTION OF DRAWINGS

[0028] ​Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of the structure of the first embodiment;

[0030] Figure 2 This is a schematic diagram of a variation of the first embodiment;

[0031] Figure 3 This is a schematic diagram of the structure of a VR optical system in the second embodiment;

[0032] Figure 4 This is a structural diagram of the third embodiment;

[0033] Figure 5 This is a schematic diagram of a variation of the third embodiment;

[0034] Figure 6 This is a schematic diagram of another variation of the fourth embodiment. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, an optical device includes at least one first device 10 and at least one second device 20. The first device 10 includes at least one first type surface 101 and one second type surface 102. The first type surface 101 and the second type surface 102 on the same first device 10 are not parallel (the first type surface 101 and the second type surface 102 can be planar, curved, or discontinuous surfaces formed by splicing multiple surfaces). The second device 20 includes a first type surface 201 opposite to the second type surface 102 of the first device 10 (the first type surface 201 is generally planar, but can also be curved or discontinuous surfaces formed by splicing multiple surfaces). A gap exists between the second type surface 102 of the first device 10 and the first type surface 201 of the second device 20 (such as an air gap, or a specially designed film layer as a gap to separate the two surfaces).

[0038] The first type of light 41 and the second type of light 42 are incident and / or emergent from the first type of surface 101 (in this example, the first type of light and the second type of light are incident and / or emergent at the same time, and for the sake of simplifying the illustration, some or all of the transmitted light rays in the schematic diagram of the present application are not strictly drawn according to Snell's law at both ends of the interface with the actual incident and refracted emergent angles, but such simplification does not affect the understanding and implementation of the present application), the first type of light 41 and the second type of light 42 have different angles with the first type of surface 101 (if the surface is a curved surface, the first type of light and the second type of light incident or emergent from the same point on the surface have different angles with the tangent line or the normal line of the tangent line at the point), the different angles can be different angle ranges, such as the angle between the first type of light 41 and the surface normal is within ±20°, and the angle between the second type of light 42 and the surface normal is less than -20° or greater than +20° (or in some applications in this example, the angle range of the second type of light can also be outside ±25° and within ±80°, in this case, the angle range belongs to -25° to -20°, +20° to +25° and outside ±80°, and no matter whether the subsequent propagation is according to the first type of light or the second type of light, it will not cause great influence on the normal operation of the system). The first type of light 41 and at least part of the second type of light 42 propagate in the first device 10 and then are incident on the second type of surface 102 of the first device 10 (or can propagate on multiple surfaces with the same number of transmission and reflection, or propagate to the second type of surface with different numbers of transmission and reflection), the angle between the first type of surface 101 and the second type of surface 102 of the first device 10 satisfies the following conditions:

[0039] The first type of light 41 is emergent from the second type of surface 102 of the first device 10 and / or incident, and the second type of light 42 incident on the second type of surface 102 of the first device 10 is reflected by the second type of surface 102.

[0040] The first type of surface 101 and the second type of surface 102 in this embodiment can also not intersect (such as a wedge-shaped device), then the angle between the first type of surface 101 and the second type of surface 102 can be obtained by extension.

[0041] If the first type of surface 101 and / or the second type of surface 102 is a curved surface or a non-continuous surface formed by multiple surfaces, the angle between the two surfaces can be defined as follows:

[0042] When the same ray enters or exits the first type surface 101 of the same first device 10 successively and then propagates to the second type surface 102 (or it can pass through the second type surface 102 first and then propagate to the first type surface 101), the angle between the ray and the two tangents at the point of entry or exit of the first type surface 101 and the second type surface 102 (i.e., the angle between the tangents after translating or extending the two tangents), or the angle between the normals of the two tangents (i.e., the angle between the normals of the two tangents after translating or extending the normals of the two tangents).

[0043] In the above situation, there may be multiple included angles between the two surfaces, but any included angle must satisfy the condition that the first type of light ray exits from and / or enters from the second type of surface 102 of the first device 10, and at least part of the second type of light ray 42 that enters the second type of surface 102 of the first device 10 is reflected by the second type of surface 102. This achieves the purpose of separating the first type of light ray 41 and the second type of light ray 42 (separating light rays at different angles).

[0044] like Figure 2 As shown, in a variation of this embodiment, the optical device may include multiple first devices and / or second devices. Multiple first devices can filter out multiple types of second-type light rays from different directions and angles; for example, the system may include four first devices (…). Figure 2 Only two of the first devices (10 and 11) are shown in the diagram. These two devices filter out light rays whose y-direction angles with surfaces 101 and 111 are greater than +40° and less than -50°, respectively. The other two devices filter out light rays whose directions are greater than +30° and less than -35° with the incident first-type surface. Multiple second devices can further modulate the first-type light rays. Multiple first and second devices can be combined in various ways throughout the device / system. For example, light rays can first enter a first device, then a second device (which in some cases can also be considered the preceding first device of the next device), separating a portion of the second-type light rays before entering a second first device, filtering out another portion of the second-type light rays, and then entering a second second device. Alternatively, light rays can first enter several first devices consecutively to filter out specific second-type light rays before entering multiple second devices. Furthermore, a single first device can also contain multiple first or second-type surfaces (which can be considered as multiple first devices joined together).

[0045] There are gaps between the surfaces of multiple first and / or second devices. The gaps are air gaps and / or filled with a medium, and / or coated with a functional film layer, thereby enabling the selective (reflection or transmission) of light at different angles between some surfaces.

[0046] In this example, after the second type of light is reflected, at least a portion of it is coupled out of the optical device or absorbed, and is separated from the optical path of the first type of light, and is coupled out of the system (not participating in subsequent functions, such as imaging); or after the first type of light passes through the second type of surface, at least a portion of it is coupled out of the optical device or absorbed.

[0047] Example 2

[0048] A VR optical system, similar to the monolithic PANCAKE solution, such as Figure 3 As shown. Image light emitted from a microdisplay (e.g., LCD, Micro OLED, Micro LED, etc.) is modulated into circular polarization and then passes through a surface (semi-transparent, semi-reflective curved surface) of the second device 20 (lens / mirror). It exits through the first type surface 201 on the second device 20, passes through a gap 312 (which can be an air gap or a gap formed by a special dielectric film that enhances light transmission at small angles while reflecting light at large angles), and then enters the corresponding second type surface 102 of the first device 10. At this point, all image light is first type light that can pass through the second type surface 102 and exits from the first type surface 101 of the first device 10. The light exits through gap 311 and enters the second type surface 112 of the first device 11. A quarter-wave plate and a polarizing reflective film are prepared on one side plane of the first device 11 (first type surface 111). The image light is modulated into S-ray by the quarter-wave plate and then reflected. At this time, the angle between the image light and the first device 10, the second type surface 102 of the first device 11, and the second type surface 112 is still smaller than the total reflection angle (or smaller than the starting reflection angle set by the angle-related reflective film). Thus, after passing through the above surfaces, the image light is modulated again by the semi-transparent and semi-reflective surface of the second device 20 and then reflected. After passing through the first device 10 and the first device 11, the light enters the first type surface 111. At this time, part of the light is modulated into P light by a quarter wave plate and exits from the first type surface 111 (as image light input to the human eye). However, in reality, due to the imperfection of the polarization device, part of the light will be reflected again by the first type surface 111 and become second type light 42 due to the change of angle (here, the second type light is generated by part of the first type light 41 on the first type surface 111 due to the device defect, which can be equivalent to input from the surface of the first type surface 111, for example, regarded as entering the first type surface 111 from the outside of the first type surface 111). This part of the light becomes stray light (second type light 42) and re-enters the system. At this time, part of the second type light will be reflected and cannot pass through because the angle between it and the second type surface 112 of the first device 11 is greater than the total reflection angle (or greater than the angle set by the angle selective reflection film on the gap). The above-mentioned second type light 42 undergoes one or more reflections / total reflections in the first device 11 and is coupled out of the system or absorbed at the edge of the first device 11. Similarly, another portion of the second type of light (another angular range) will be coupled out of the system or absorbed after undergoing one or more reflections in the first device 10.

[0049] The above scheme can be further supplemented with multiple first devices to filter out stray light exceeding the angular range in another direction (for example, the aforementioned scheme filters out vertical stray light, and adding two more first devices can filter out horizontal stray light / second type of light). The above scheme can also be used in multi-element PANCAKE VR systems (such as two, three, or four lenses / mirrors).

[0050] Example 3

[0051] like Figure 5 As shown, a first device 10 includes a cross-section shaped like a triangular prism (or with chamfered edges forming a wedge or polygon), and its material has a refractive index of 1.60. A second device 20 also includes a triangular or wedge-shaped waveguide (the material and its refractive index may be the same as or different from the first device 10). All incident rays have an angle (angle of incidence) between the incident ray and the normal to the first type surface 101 within ±50°. Rays with an angle less than +30° to the normal of surface 101 are considered valid first-type rays 41 and need to propagate to the second device 20, while rays with an angle greater than +40° to the normal of the first type surface 101 are considered stray light (second-type rays 42) and need to be filtered out before entering the second device 20. The angle between the first type surface 101 and the second type surface 102 of the first device 10 is 16°. Therefore, the angle between the first type ray 41 and the normal of the first type surface 101 is less than 30° (corresponding to an angle of 17.42° between the ray 41 and the normal of the first type surface 101 after incident on the first device 10 is less than 34° and can exit from the second type surface 102. However, the angle between the second type ray 42 and the surface 102 after incident on the first device 10 is greater than 39° (the total internal reflection angle is 38.68° for a 1.60 refractive index medium). Therefore, the ray 42 will be reflected by the second type surface 102 and exit from the system or be absorbed. The second type surface 102 corresponds to the first type surface 201 (they have the same surface shape and are parallel). There is an air gap of <10µm between the second type surface 102 and the first type surface 201. Both the second type surface 102 and the first type surface 201 are coated with an antireflection coating to increase light transmittance, thereby improving the transmittance of the effective light 41 on the transmitting surfaces 102 and 201. By reasonably setting the angle between the first type surface 101 and the second type surface 102, the above solution can completely filter out stray light with an angle very close to that of the effective light.

[0052] In this embodiment, the second device 20 is connected to several other optical devices, which can further modulate the effective light.

[0053] Example 4

[0054] like Figure 6As shown, the system comprises a first device 10 and a second device 20, light ray 411 and light ray 412 are input into the first device 10 from the former stage device of the system (there is a gap between the first device 10 and the former stage device) through the first surface 1010, wherein the light ray 412 reaches the first surface 1010 again after being reflected on the upper surface of the first device 10, at this time, due to the change of the reflection angle, the angle between the light ray 412 and the first surface 1010 is greater than the total reflection angle, the light ray 412 will be further changed in angle by the first surface 1010, and then when it reaches the second surface 102, the angle between the light ray 412 and the second surface 102 is greater than the total reflection angle, thus the light ray 412 at this time has become the second light ray 422 (which can be equivalent to the second light ray generated from the first surface 1010, in this example, the first light ray and the second light ray can be defined as the first light ray when the angle between the light ray and the second surface 102 is less than the total reflection angle, and the second light ray when the angle between the light ray and the second surface 102 is greater than the total reflection angle), and the second light ray 422 is reflected by the second surface 102 and then exits from the first surface 1011. The light ray 411 is also input into the first device 10 from the former stage device of the system (there is a gap between the first device 10 and the former stage device) through the first surface 1010, and it directly reaches the second surface 102 without passing through other surfaces in the first device 10, at this time, the angle between the light ray 411 and the second surface 102 is less than the total reflection angle (which belongs to the first light ray), and the light ray 411 will pass through the second surface 102 and the gap 312 and enter the second device 20, and then it is reflected by the upper surface of the second device 20 (in this example, the upper surface of the second device 20 is located in the same plane as the upper surface of the first device 10), and then it passes through the second surface 102 again and returns to the first device 10, and then the light ray 411 is incident on the first surface 1010 again, at this time, the angle between the light ray 411 and the first surface 1010 is greater than the total reflection angle, and the light ray 411 will be reflected by the first surface 1010. The angle of the light ray 411 is changed again after being reflected by the first surface 1010, and the angle between the light ray 411 and the second surface 102 is greater than the total reflection angle, and the light ray 411 changes into the second light ray 421 (which can be regarded as the second light ray generated on the first surface 1010 or the second light ray input into the first surface 1010, that is, the angle of the light ray after being reflected by the first surface 1010 for the second time is completely different from the angle of the light ray 411 after being transmitted through the first surface 1010 for the first time, which can be regarded as two different types of light rays, and the optical processes of the two types of light rays on the second surface 102 are reflection and transmission, respectively, which are also completely different), and the second light ray 421 is reflected by the second surface 102 again and then exits from the first surface 1011.

[0055] In some applications, the optical path in this embodiment can also be applied reversely (according to the principle of reversibility of optical path, the input of light can become output, and the output becomes input, the whole optical path is applied reversely), in addition, due to the increase of the angle selection area in the device to distinguish the light, in some waveguide applications, this embodiment can also be combined with other devices to further reduce the volume (such as thickness) of the system.

[0056] In this embodiment, a plurality of first devices can also be added to filter out stray light in different directions and different angle ranges.

[0057] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0058] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other without conflict.

Claims

1. An optical device, characterized by The optical device comprises: a first device and a second device; the first device comprises one or more first-type surfaces and one or more second-type surfaces; the second device comprises a first-type surface opposite to the second-type surface of the first device; a gap exists between the second-type surface of the first device and the first-type surface of the second device; the angle between the first-type light and the first-type surface is different from the angle between the second-type light and the first-type surface, and / or the angle between the first-type light and the second-type surface is different from the angle between the second-type light and the second-type surface; at least part of the first-type light and at least part of the second-type light propagate in the first device after passing through the first-type surface to the second-type surface of the first device; the angle between the first-type surface and the second-type surface of the first device satisfies the following condition: at least part of the first-type light is transmitted from the second-type surface of the first device, and at least part of the second-type light is reflected by the second-type surface of the first device; or at least part of the first-type light is reflected by the second-type surface of the first device, and at least part of the second-type light is transmitted from the second-type surface of the first device.

2. The optical device of claim 1, wherein, at least part of the second-type light is reflected or transmitted by the second-type surface, and is coupled out of the optical device or is absorbed; or at least part of the first-type light is transmitted or reflected by the second-type surface, and is coupled out of the optical device or is absorbed. the first-type light or the second-type light is coupled into the second device through the first-type surface on the second device after being transmitted through the second-type surface.

3. The optical device of claim 1, wherein, the second device comprises one or more of the following devices: a lens, a prism, a mirror, a half-mirror, a waveguide, an optical fiber, an optical rod, a light-absorbing device, a light-reflecting bowl, a lens array, a prism array, a grating, a spatial light modulator.

4. The optical device of claim 1, wherein, the cross-section of the first device is triangular, wedge-shaped, polygonal, or has a curved shape.

5. The optical device of claim 1, wherein, one or more of the first-type surfaces and the second-type surfaces of the optical device are prepared with one or more functional film layers.

6. The optical device of claim 1, wherein, the number of the first device and / or the second device is plural.

7. The optical device of claim 1, wherein, a gap exists between the surfaces of the plural first devices and / or the plural second devices.

8. The optical device of claim 7, wherein, the first-type light is converted into the second-type light after passing through the first-type surface, and / or the second-type light is converted into the first-type light after passing through the first-type surface.

9. The optical device of claim 1, wherein, the first-type light and the second-type light undergo the same optical process on the first-type surface, but undergo different optical processes on the second-type surface.

10. The optical device of claim 1, wherein, The optical device comprises the optical device of any one of claims 1-10.

11. An optical system characterized by comprising: The optical device comprises the optical device of any one of claims 1-10.

12. An optical device, characterized by ​

Images