CN215375955U - Optical module, near-to-eye display system and near-to-eye display equipment - Google Patents

Abstract

The utility model provides an optical module, a near-eye display system and a near-eye display device, which relate to the technical field of optics, wherein the optical module comprises: a light source; the waveguide comprises a coupling-in surface, a side surface and an inclined plane, wherein the coupling-in surface is used for coupling target light emitted by the light source into the waveguide, and the side surface is used for totally reflecting the target light to the inclined plane; the reflective micro-nano optical element is attached to the inclined plane and is used for diffracting the target light incident to the inclined plane; and the compensating mirror is attached to one surface of the reflective micro-nano optical element, which is far away from the waveguide, and is used for enabling the outside light to enter human eyes without distortion. According to the optical module, the near-eye display system and the near-eye display equipment, the reflective micro-nano optical element is attached to the inclined plane of the waveguide, so that the incident angle of imaging light on the reflective micro-nano optical element is reduced, the diffraction efficiency is improved, and the field angle is increased.

Description

Optical module, near-to-eye display system and near-to-eye display equipment

Technical Field

The utility model relates to the technical field of optics, in particular to an optical module, a near-eye display system and near-eye display equipment.

Background

The near-eye display system, originally originated in the field of air force, mainly solves the trouble of drivers facing a great deal of information collected by increasingly precise instruments and weapon systems on airplanes, and can completely present all information of each instrument and meter in a field of view in front of the drivers by using a near-eye display product so that the drivers concentrate on operating airplanes and aiming. Along with the study and knowledge of people on near-eye display products, the application field of the near-eye display products is continuously expanded, in recent years, along with the development of electronic digital consumer products and optical technologies, more and more sports glasses, helmets and the like are carried with near-eye display systems, some auxiliary information is dynamically displayed in real time in the movement process of a user, and the user is helped to better know other information.

An optical module of an existing near-eye display system generally includes a light beam generator for emitting a light beam, a waveguide for totally reflecting the light beam, and a light beam combiner for changing a propagation direction of the light beam, so that the light beam emitted from the light beam generator enters a human eye through the waveguide and the light beam combiner. However, the optical module of the conventional near-eye display system has the problems of low diffraction efficiency and small angle of view.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide an optical module, a near-eye display system and a near-eye display device, which are used for improving diffraction efficiency and increasing the field angle.

In a first aspect, an embodiment of the present invention provides an optical module, including:

a light source;

a waveguide including a coupling-in surface for coupling target light emitted from the light source into the waveguide, a side surface for totally reflecting the target light to the inclined plane, and an inclined plane;

the reflective micro-nano optical element is attached to the inclined plane and used for diffracting the target light incident to the inclined plane, so that the target light is output to human eyes through the waveguide;

the compensating mirror is attached to one surface, far away from the waveguide, of the reflective micro-nano optical element and used for enabling outside light penetrating through the reflective micro-nano optical element and the waveguide to enter human eyes without distortion.

Furthermore, the compensating mirror comprises an incident surface and an emergent surface which are oppositely arranged, and the incident surface and/or the emergent surface are curved surfaces.

Further, the reflective micro-nano optical element is a holographic optical element.

Further, the side surface includes two parallel planes or two curved surfaces.

Further, the coupling-in surface comprises a spherical surface or an aspherical surface.

Further, the light source includes an organic light emitting diode or a micro light emitting diode.

Further, the optical module further comprises an optical lens disposed between the light source and the waveguide for refracting the target light emitted by the light source to the coupling-in surface.

In a second aspect, an embodiment of the present invention further provides a near-eye display system, including the optical module according to the first aspect.

In a third aspect, an embodiment of the present invention further provides a near-eye display device, including the near-eye display system in the second aspect.

Further, the near-eye display device is an AR swimming goggle.

In an optical module, a near-eye display system, and a near-eye display device provided in an embodiment of the present invention, the optical module includes: a light source; the waveguide comprises a coupling-in surface, a side surface and an inclined plane, wherein the coupling-in surface is used for coupling target light emitted by the light source into the waveguide, and the side surface is used for totally reflecting the target light to the inclined plane; the reflective micro-nano optical element is attached to the inclined plane and used for diffracting the target light incident to the inclined plane and outputting the target light to human eyes through the waveguide; the compensating mirror is attached to one surface, far away from the waveguide, of the reflective micro-nano optical element and is used for enabling outside light penetrating through the reflective micro-nano optical element and the waveguide to enter human eyes without distortion. According to the optical module, the near-eye display system and the near-eye display device, the reflective micro-nano optical element is attached to the inclined plane of the waveguide, so that the incident angle of imaging light on the reflective micro-nano optical element is reduced, the diffraction efficiency is improved, and the field angle is increased.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

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

fig. 2 is a schematic diagram illustrating a theoretical principle of an optical module according to an embodiment of the present invention;

fig. 3 is a schematic optical path diagram of an optical module according to an embodiment of the present invention;

fig. 4 is a schematic optical path diagram of another optical module according to an embodiment of the present invention;

fig. 5 is a schematic optical path diagram of another optical module according to an embodiment of the present invention.

Icon: 110-a light source; 120-an optical lens; 130-a waveguide; 131-a coupling-in face; 132-side; 1321-parallel planes; 1322-curved surface; 133-inclined plane; 140-a reflective micro-nano optical element; 150-a compensation mirror; 151-incident plane; 152-exit face.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In an optical module of a current near-eye display system, a beam combiner changes a propagation direction of a light beam by diffracting the light beam incident thereon, and the diffraction has angular selectivity, that is, the diffraction efficiency of light rays incident at a certain angle (or a small angle range) is high, while the diffraction efficiency of light rays incident at other angles is low, and when an incident angle of imaging light rays on the beam combiner is large, the diffraction efficiency is low; since the beam combiner is attached to the surface on one side of the waveguide, which is a surface for total reflection, and the propagation of light in the waveguide needs to satisfy the total reflection condition, the effective imaging beam angle is limited, which leads to a limitation of the FOV (Field of view) of the whole system. Based on this, the optical module, the near-eye display system and the near-eye display device provided by the embodiment of the utility model can reduce the incident angle of imaging light on the reflective micro-nano optical element, thereby improving diffraction efficiency and increasing the field angle.

For the understanding of the present embodiment, a detailed description will be given to an optical module disclosed in the present embodiment.

The embodiment of the utility model provides an optical module which is applied to a near-eye display system. Referring to fig. 1, a schematic structural diagram of an optical module is shown, which includes: a light source 110; an optical lens 120 for refracting the target light emitted from the light source 110 to a coupling-in surface 131 of the waveguide 130; a waveguide 130, the waveguide 130 including a coupling-in surface 131, a side surface 132, and an inclined plane 133, the coupling-in surface 131 for coupling the target light emitted from the light source 110 into the waveguide 130, the side surface 132 for totally reflecting the target light to the inclined plane 133; a reflective micro-nano optical element 140, the reflective micro-nano optical element 140 being attached to the inclined plane 133, and being configured to diffract the target light incident on the inclined plane 133, so that the target light is output to human eyes via the waveguide 130; and a compensating mirror 150, wherein the compensating mirror 150 is attached to one surface of the reflective micro-nano optical element 140 away from the waveguide 130, and the compensating mirror 150 is used for enabling the external light passing through the reflective micro-nano optical element 140 and the waveguide 130 to enter human eyes without distortion.

The light source 110, the optical lens 120, the waveguide 130, and the reflective micro-nano optical element 140 are sequentially disposed in a direction along which light travels. The Light source 110 is used to provide a display source, and the Light source 110 may be an OLED (Organic Light-Emitting Diode) or a Micro LED (Micro Light-Emitting Diode). Such a light source 110, which is self-luminous or integrated, such as an OLED or Micro LED, is small in size, so that an optical module including the light source 110 can be applied to small devices such as glasses, swimming goggles, and the like. It should be noted that the present invention is not limited to the light source 110 such as OLED or Micro LED, and other light sources may be adopted in other application scenarios.

The optical lens 120 is disposed between the light source 110 and the waveguide 130, and the optical lens 120 refracts the target light emitted from the light source 110 so that the target light is incident on the coupling surface 131 of the waveguide 130.

The above-mentioned waveguide 130 functions to control a propagation path of light rays entering therein, and the waveguide 130 serves to refract and totally reflect incident target light and finally output it into the human eye. Specifically, the coupling-in surface 131 of the waveguide 130 is used for coupling the target light emitted from the light source 110 into the waveguide 130, and the target light satisfies a total reflection condition at an interface between the side surface 132 of the waveguide 130 and an external medium (usually air), and the target light after multiple total reflections is incident on the inclined plane 133 to change a propagation direction and is refracted and then emitted. The coupling-in surface 131 of the waveguide 130 may be spherical, aspherical or other optical imaging surface. The side 132 of the waveguide 130 may be planar, spherical, aspherical, or other optical imaging surface. It should be noted that, the present invention does not limit the number of total reflections occurring in the waveguide 130, and the total reflection numbers corresponding to the light incident at different angles may be different.

The reflective micro-nano optical element 140 is a planar device having a power for diffracting the target light incident on the surface thereof, and can independently change the exit directions of the light rays having different incident angles in the target light, and the front and rear surfaces thereof can be respectively cemented with the waveguide 130 and the compensating mirror 150. The reflective micro-nano optical element 140 has wavelength selectivity and angle selectivity, can diffract light of a specific wavelength and a specific angle by 100% and transmit other light by 100%, and can realize brighter image display and more efficient transmission of external light compared to a beam splitter having a certain ratio of reflectivity to transmissivity. The reflective micro-nano optical element 140 can obtain an optical field with any intensity distribution on a far-field imaging surface by modulating an incident optical field.

The reflective micro-nano optical element 140 may be manufactured by the following two methods: 1. a nano-imprint method for etching a step or a continuous relief structure on the surface of an optical device; 2. holographic method for recording and reproducing holograms by exposure interference. Wherein, record means: a hologram is an optical method of recording a wavefront of light waves on a photosensitive material. In the application of grating preparation, two modulated light waves with specific wave fronts and according with coherence conditions are generally irradiated on a photosensitive material to form a volume grating structure with gradually-changed material refractive index. Mathematically, the light intensity function can be modulated by the phase and amplitude of two light waves, and finally the refractive index gradient function is formed on the material. The reproduction means: when the light wave with the same information as the exposure light wave irradiates the hologram, the light beam with the same information as the other exposure light wave is diffracted out through the action of the hologram, and the wave front is reproduced. Likewise, it can be understood as the inverse modulation process of the refractive index function.

Alternatively, the reflective micro-nano optical element 140 may employ a HOE (holographic optical element) storing a hologram using a holographic principle, which has a focal power although the outer shape is a plane, and may have a large variation range of the focal power when designed, thereby being advantageous in image quality optimization and image display.

The compensating mirror 150 is used to make the external light normally enter human eyes, so as to prevent the human eyes from observing distorted external scenes. The external light sequentially passes through the compensating mirror 150, the reflective micro-nano optical element 140 and the waveguide 130 to enter human eyes, the compensating mirror 150, the waveguide 130 and the reflective micro-nano optical element 140 form an integral device, and the integral device can be equivalent to a parallel plane glass plate, so that the human eyes are prevented from observing a distorted external scene.

The compensating mirror 150 may include an incident surface 151 and an exit surface 152 that are disposed opposite to each other, and both the incident surface 151 and the exit surface 152 may be a plane or a curved surface, or one of the two may be a plane and the other may be a curved surface. Alternatively, the compensating mirror 150 may perform a function of vision correction by providing at least one of the incident surface 151 and the exit surface 152 with a specific curved surface.

The imaging of the optical module provided by the embodiment of the utility model belongs to the imaging of a normal visual system, the reflective micro-nano optical element 140 is glued on an inclined plane 133 with a specific inclination angle, and light rays are diffracted and emitted at different angles when being incident on the inclined plane 133. The advantage of the reflective micro-nano optical element 140 being placed on the inclined plane 133 will be explained with reference to fig. 2.

As shown in fig. 2, assuming that the incident angles of the two marginal field rays on the horizontal plane S1 are α and β, respectively, the inclined plane 133 is S2, and the inclined angle of S2 is θ, it is inferred from the geometric relationship that the incident angles of the two marginal field rays on the horizontal plane S2 are α - θ and β - θ, respectively, which indicates that the inclined plane 133 can effectively reduce the incident angle of the rays thereon, so that the diffracted rays can have higher diffraction efficiency under the same refractive index modulation degree, and the optical module has higher display brightness; meanwhile, the effective imaging beam angle can be increased under the condition of similar diffraction efficiency, and the field angle of the optical module is further increased.

In the optical module provided by the embodiment of the present invention, the target light emitted from the light source 110 is processed by the optical lens 120, the waveguide 130 and the reflective micro-nano optical element 140, and then is output by the waveguide 130 to enter human eyes for imaging, and simultaneously, the human eyes can observe an undistorted external scene through the waveguide 130 and the compensating mirror 150. According to the optical module, the reflective micro-nano optical element 140 is attached to the inclined plane 133 of the waveguide 130, so that the incident angle of imaging light on the reflective micro-nano optical element 140 is reduced, the diffraction efficiency is improved, and the field angle is increased.

In one possible implementation, referring to the schematic optical path diagram of an optical module shown in fig. 3, the side surface 132 includes two parallel planes 1321, and the incident surface 151 and the exit surface 152 of the compensation mirror 150 are both planar; the light emitted from the light source 110 passes through the optical lens 120 and then is refracted through the coupling surface to enter the waveguide 130, the light angle satisfies the total reflection condition in the waveguide 130 having two parallel planes 1321 and totally reflects on the two parallel planes 1321 once, the light of the propagation path controlled by the waveguide 130 is incident on the reflective micro-nano optical element 140 and is diffracted, the light is output through the waveguide 130 according to the designed light path to enter human eyes for imaging, and simultaneously, the human eyes can observe an undistorted external scene through the waveguide 130 and the compensating mirror 150. The optical module has the advantages of less curved surfaces (only the light-emitting surface of the optical lens 120 and the coupling-in surface of the waveguide 130 are curved surfaces), simpler processing, manufacturing and assembly, lower production cost, smaller product size, lighter weight and more convenient wearing.

In another possible implementation manner, referring to the optical path schematic diagram of another optical module shown in fig. 4, the side surface 132 includes two curved surfaces 1322, each of the two curved surfaces 1322 may be a spherical surface, an aspheric surface, or another optical imaging surface, and the incident surface 151 and the exit surface 152 of the compensation mirror 150 are both planar surfaces; the light emitted from the light source 110 passes through the optical lens 120 and then is refracted through the coupling surface to enter the waveguide 130, the angle of the light ray satisfies the total reflection condition in the waveguide 130 with two curved surfaces 1322 and is totally reflected once on each of the two curved surfaces 1322, the light ray of the propagation path controlled by the waveguide 130 is incident on the reflective micro-nano optical element 140 and is diffracted, the light ray is output through the waveguide 130 according to the designed light path to enter human eyes for imaging, and simultaneously, the human eyes can observe an undistorted external scene through the waveguide 130 and the compensating mirror 150. Since the curved surface 1322 in the waveguide 130 increases the degree of freedom in design, the aberration can be controlled more effectively, and the display effect can be improved.

In another possible implementation manner, referring to the optical path schematic diagram of another optical module shown in fig. 5, the side surface 132 of the waveguide 130 may be two parallel planes or two curved surfaces, and both the incident surface 151 and the exit surface 152 of the compensation mirror 150 are curved surfaces; the light emitted by the light source 110 passes through the optical lens 120 and then is refracted through the coupling surface to enter the waveguide 130, the angle of the light meets the total reflection condition in the waveguide 130 and totally reflects twice, the light of the propagation path is controlled by the waveguide 130 to be incident on the reflective micro-nano optical element 140 and be diffracted, and the light is output through the waveguide 130 according to the designed light path to enter human eyes for imaging; the incident surface 151 and the exit surface 152 may be curved surfaces having different curvatures, and the function of vision correction is achieved by the combination of the incident surface 151 and the exit surface 152.

In summary, the optical module provided by the embodiment of the utility model has the following advantages: 1. the reflective micro-nano optical element is attached to the inclined plane of the waveguide, so that the incident angle of imaging light on the reflective micro-nano optical element is reduced, the diffraction efficiency is improved, and the field angle is increased; 2. by arranging the reflective micro-nano optical element, brighter image display and more efficient external light transmission are realized; 3. the reflective micro-nano optical element is a planar device with focal power, and has advantages in the aspects of image quality optimization and imaging display; 4. the introduced reflective micro-nano optical element can only adopt one transmission spherical surface (the coupling-in surface of the waveguide) and one free-form surface (the light-emitting surface of the optical lens), has smaller product size, is light, thin and light, and has lower difficulty in manufacturing and assembling, thereby having lower actual cost; 5. the incident surface and/or the emergent surface of the compensating mirror are/is set to be the curved surface, so that the function of vision correction is realized, and the application range is wider.

The embodiment of the utility model also provides a near-to-eye display system which comprises the optical module and a main control chip, wherein the main control chip is used for controlling the target light emitted by the light source so as to control the displayed content.

The embodiment of the utility model also provides near-eye display equipment comprising the near-eye display system. The near-eye display device may be an AR (Augmented Reality) swimming goggle, an AR glasses, a helmet, or the like.

The near-eye display system and the near-eye display device provided by the embodiment have the same implementation principle and the same technical effect as those of the optical module embodiment, and for the sake of brief description, reference may be made to corresponding contents in the optical module embodiment where no part is mentioned in the near-eye display system and the near-eye display device embodiment.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In addition, in the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. An optical module, comprising:

a light source;

a waveguide including a coupling-in surface for coupling target light emitted from the light source into the waveguide, a side surface for totally reflecting the target light to the inclined plane, and an inclined plane;

the reflective micro-nano optical element is attached to the inclined plane and used for diffracting the target light incident to the inclined plane, so that the target light is output to human eyes through the waveguide;

the compensating mirror is attached to one surface, far away from the waveguide, of the reflective micro-nano optical element and used for enabling outside light penetrating through the reflective micro-nano optical element and the waveguide to enter human eyes without distortion.

2. The optical module of claim 1, wherein the compensation mirror comprises an incident surface and an exit surface that are disposed opposite to each other, and wherein the incident surface and the exit surface are both flat surfaces or at least one of the incident surface and the exit surface is a curved surface.

3. The optical module of claim 2 wherein the compensating mirror has vision correcting capabilities.

4. An optical module according to claim 1, wherein the reflective micro-nano optical element is a holographic optical element.

5. The optical module of claim 1 wherein the side surface comprises two parallel planes or two curved surfaces; the coupling-in surface comprises a spherical or aspherical surface.

6. The optical module of claim 1, wherein the light source comprises an organic light emitting diode or a micro light emitting diode.

7. The optical module according to any one of claims 1-6, further comprising an optical lens disposed between the light source and the waveguide for refracting target light emitted by the light source to the coupling-in face.

8. A near-eye display system comprising the optical module of any one of claims 1-7.

9. A near-eye display device comprising the near-eye display system of claim 8.

10. The near-eye display device of claim 9 wherein the near-eye display device is an AR swimming goggle.

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