Near-to-eye display structure and method based on MEMS technology

Abstract

The invention provides a near-to-eye display structure and method based on an MEMS technology, and belongs to the technical field of near-to-eye display. A near-to-eye display structure based on an MEMS technology comprises a plurality of single pixel point structures with certain transparency, each single pixel point structure comprises a transparent substrate, a light source, a collimating micro lens and an MEMS Fabry-Perot cavity structure, and the collimating micro lens comprises a first light incident surface, a first light emergent surface, a second light incident surface, a side surface and a second light emergent surface; the lens and the screen are combined, the resolution is remarkably improved to 40-50 times that of a traditional device, meanwhile, the multi-angle adjusting capacity of the light source structure breaks through the limitation of the field angle and can reach 90 degrees or above, in addition, the scheme avoids using a miniature screen and a projection screen component, the cost is reduced, and the application range is wide. The size and the weight of the device are optimized, a software correction step needed by optical phase difference is omitted, and double improvement of performance and efficiency is achieved.

Description

Technical Field

[0001] The present invention relates to the field of near-eye display technology, and in particular to a near-eye display structure and method based on MEMS technology. Background Art

[0002] AR / VR technology is an intelligent device that transmits virtual image and text information through optical means and allows users to interact. It is gradually transitioning from academic research to commercial market.

[0003] However, the near-eye display technology solutions based on micro-displays currently on the market have many limitations, such as resolution limited by the micro-display itself, small field of view, resulting in limited user experience. In addition, these solutions also have the problems of high price, large device size and heavy weight, and optical elements will produce optical aberration when transmitting images, requiring additional algorithms for image quality correction. These factors have hindered the widespread promotion and application of virtual reality technology. To this end, in response to this problem, the present invention proposes a near-eye display structure and method based on MEMS technology. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a near-eye display structure and method based on MEMS technology that can overcome the above problems or at least partially solve the above problems.

[0005] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: a near-eye display structure based on MEMS technology, including multiple single-pixel point structures with a certain degree of transparency, each single-pixel point structure includes a transparent substrate, a light source, a collimating microlens and a MEMS Fabry-Perot cavity structure, wherein the collimating microlens includes: a first light incident surface, used to receive the central light from the light source and guide the central light into the interior of the collimating microlens; a first light output surface, corresponding to the first light incident surface, used to output the refracted central light in a parallel form; a second light incident surface, symmetrically located on both sides of the first light incident surface, used to receive the edge light from the light source and guide the edge light into the interior of the collimating microlens; a side surface, used to totally reflect the edge light entering the collimating microlens after being refracted by the second light incident surface, so as to change the transmission path of the light; a second light output surface, symmetrically located on both sides of the second light incident surface and adjacent to the side surface, used to output the totally reflected edge light in the form of a preset angle.

[0006] Preferably, the transparent substrate is made of a bendable plastic material or an inflexible rigid material, wherein the bendable plastic material includes PEN or PET, and the inflexible rigid material includes hard plastic or glass.

[0007] Preferably, the light source is a self-luminous structure, the wavelength range of which covers the spectral band of visible light, and the brightness of the light source can be controlled by adjusting the current or voltage.

[0008] Preferably, the collimating microlens is a lens of micrometer size with focusing effect.

[0009] The present invention also provides a near-eye display method based on MEMS technology, comprising the following steps: S1. When the light source emits light, the collimating microlens is responsible for collimating and focusing the light to ensure that the light is output at a specific angle and intensity; S2, the MEMS Fabry-Perot cavity structure adjusts the wavelength and phase of the outgoing light according to the control signal, thereby realizing color display and image construction; S3. By adjusting the brightness of the light source in each single pixel structure and the parameters of the MEMS Fabry-Perot cavity structure, precise control of the image and color of the entire display area can be achieved.

[0010] Preferably, the angle of the light beam emitted by the light source in step S1 includes selecting a flexible transparent material as a base material, and bonding the flexible screen to a transparent glass lens with a specific radius, so that each pixel point fits the surface structure to form a structure perpendicular to the center of the lens, or placing a parallel-structured reflective plate at the front end of the transparent screen, and a reflective film of different angles is coated at regular intervals inside the reflective plate, so that the emitted parallel light beams become parallel light beams of different angles after passing through the reflective plate.

[0011] Preferably, in step S2, the MEMS Fabry-Perot cavity structure adjusts the wavelength and phase of the emitted light according to the control signal, by using the light to reflect back and forth between the two reflectors to form a fixed phase difference, so that the formula m*λ=2*n is satisfied. gap The light wave λ of *h*cos(α) forms interference effect outside the cavity and passes through, where m is the order, n is gap is the refractive index of the medium inside the Fabry-Perot cavity, h is the thickness of the gap between the two reflectors of the Fabry-Perot cavity, and α is the incident angle of the light beam entering the Fabry-Perot cavity. By controlling the gap thickness h of the Fabry-Perot cavity or the refractive index n of the intermediate medium, gap To achieve the purpose of changing the output wavelength.

[0012] Preferably, in step S3, the single pixel structure is set as a square area with a side length of D, which is distributed on the surface of the lens in a parallel structure to form a two-dimensional (x, y) area array display structure. The center of each pixel structure is an opaque imaging area composed of a square area with a side length of d, and the area outside the area is a transparent area without any element blocking it. By adjusting the size of the imaging area relative to the pixel area, the transparency of the display screen can be selectively adjusted.

[0013] Preferably, when the single pixel structure in step S3 is displayed near the eye, the collimating microlens is placed at a position L3 away from the light source, with a focal length of f1, and the image plane B of the light source is focused at L1 in front of the eyeball to form a virtual image B', and B' is then imaged B'' through the lens of the eyeball; and the position of the virtual image plane L1 away from the eyeball is optimized according to the following formula: 1 / L3-1 / (L1-L4)=1 / f1 1 / L1+1 / L2=1 / f2 Among them, L2 is the image distance from the image plane in the eye to the lens, L4 is the distance from the lens surface to the eyeball, and f2 is the focal length of the human eye lens. In order to enable pixels at different positions to form images at the corresponding positions of the eyeball, the emission angle of each pixel point needs to be determined according to its position away from the center. The emission angle of the nth pixel point from the center is expressed as: Β(n)=arctan(n*D / L4) Using this method, the field of view of the system is twice the angle of incidence corresponding to the edge pixel point, that is: FOV=2*p Among them, p is the emission angle corresponding to the edge pixel.

[0014] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art: the present invention significantly improves the resolution to forty to fifty times that of traditional devices by merging the lenses with the screen. At the same time, the multi-angle adjustment capability of the light source structure breaks the limitation of the field of view angle, which can reach ninety degrees or more. In addition, the scheme avoids the use of micro-screens and projection components, reduces costs, optimizes the size and weight of the equipment, and eliminates the software correction steps required due to optical aberrations, thereby achieving a double improvement in performance and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the overall structure of a near-eye display structure based on MEMS technology provided by the present invention; Figure 2 A schematic diagram of a collimating microlens structure of a near-eye display structure based on MEMS technology provided by the present invention; Figure 3 A schematic diagram of a top view of a near-eye display structure based on MEMS technology provided by the present invention; Figure 4 A schematic diagram of a near-eye imaging structure of a near-eye display structure based on MEMS technology provided by the present invention; Figure 5 A schematic diagram of the color output control of a MEMS Fabry-Perot cavity structure of a near-eye display structure based on MEMS technology provided by the present invention; Figure 6A schematic diagram of the near-eye imaging principle of a pixel structure of a near-eye display structure based on MEMS technology provided by the present invention; Figure 7 A schematic diagram of a beam angle of a near-eye display structure based on MEMS technology provided by the present invention; Figure 8 A schematic diagram of a light beam emission angle control for a near-eye display structure based on MEMS technology provided by the present invention Figure 1 ; Fig. 9 A schematic diagram of a light beam emission angle control for a near-eye display structure based on MEMS technology provided by the present invention Figure 2 ; Fig.10 A schematic diagram of a screen and pixel structure of a near-eye display structure based on MEMS technology provided by the present invention; Fig.11 A schematic diagram of the final structure of a display device with a near-eye display structure based on MEMS technology provided by the present invention.

[0016] In the figure: 1. transparent substrate; 2. MEMS Fabry-Perot cavity structure; 3. collimating microlens; 31. first light incident surface; 32. first light emitting surface; 33. second light incident surface; 34. second light emitting surface; 35. side surface; 4. light source. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments so that those skilled in the art can implement the invention with reference to the description.

[0018] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0019] In the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0020] Reference Figure 1-Figure 11A near-eye display structure based on MEMS technology includes a plurality of single-pixel structures with a certain degree of transparency, each of which includes a transparent substrate 1, a light source 4, a collimating microlens 3 and a MEMS Fabry-Perot cavity structure 2. The imaging area in each single-pixel structure emits parallel light beams with a certain angle through the synergistic effect of the MEMS Fabry-Perot cavity structure 2 and the collimating microlens 3. These light beams form specific images or information in space. At the same time, the display brightness and wavelength λ of the light source 4 can be accurately adjusted through circuit control, thereby realizing dynamic regulation of display content; Among them, the collimating microlens 3 includes: a first light incident surface 31, used to receive the central light from the light source 4 and guide the central light into the interior of the collimating microlens 3; a first light emitting surface 32, corresponding to the first light incident surface 31, used to output the refracted central light in a parallel form; a second light incident surface 33, symmetrically located on both sides of the first light incident surface 31, used to receive the edge light from the light source 4, and guide the edge light into the interior of the collimating microlens 3; a side surface 35, used to totally reflect the edge light entering the interior of the collimating microlens 3 after being refracted by the second light incident surface 33, so as to change the transmission path of the light; a second light emitting surface 34, symmetrically located on both sides of the second light incident surface 33 and adjacent to the side surface 35, used to output the totally reflected edge light in the form of a preset angle.

[0021] The collimating microlens 3 in this embodiment includes two main light paths, namely a first light path and a second main light path. The incident light of the first main light path is the central light of the light source 4. The central light of the light source 4 is incident from the first light incident surface 31, enters the collimating microlens 3 after being refracted by the first light incident surface 31, and reaches the first light exiting surface 32, and exits from the first light exiting surface 32. The incident light of the second light path is the edge light of the light source 4. The edge light of the light source 4 is incident from the second light incident surface 33, enters the collimating microlens 3 after being refracted by the second light incident surface 33, and reaches the side surface 35. Since the side surface 35 is a total reflection surface, the light After being reflected by the side surface 35, the light reaches the second light emitting surface 34 and forms an angle of about 30 with the normal of the second light emitting surface 34, and then is emitted through the second light emitting surface 34. Through this design, the collimating microlens 3 can simultaneously process the central light and the edge light of the light source 4, ensuring that the central light and the edge light of the light source 4 can be emitted in a suitable manner, which not only improves the clarity of the image, but also expands the display viewing angle range. In addition, through circuit control, the display brightness and wavelength λ of the light source 4 can also be accurately adjusted. This dynamic regulation capability enables the near-eye display structure to display richer and more dynamic content.

[0022] Furthermore, in order to make the transparent substrate 1 have both flexibility and stability to meet the needs of different application scenarios, the transparent substrate 1 can adopt a bendable plastic material, such as PEN (polyethylene naphthalate) or PET (polyethylene terephthalate). These materials give the system a higher degree of design freedom, facilitate lightweight and wearability, and are very suitable for application scenarios that require flexibility and portability. At the same time, the transparent substrate 1 can also choose an inflexible rigid material, such as certain types of hard plastic or glass. These materials ensure the stability and long-term reliability of the display effect with their excellent optical properties and durability, and are particularly suitable for occasions that have strict requirements on the display effect and do not require flexibility. Therefore, the material selection of the transparent substrate 1 can be flexibly adjusted according to the needs of the specific application scenario to achieve the best performance and effect.

[0023] Furthermore, the light source 4 is a self-luminous structure, and its wavelength range covers the spectral band of visible light, approximately from 400nm to 780nm, so it can present rich and colorful colors, and the brightness of the light source 4 can be controlled by adjusting the current or voltage, and the brightness of the light source 4 can be precisely controlled. This flexibility enables the light source 4 to adapt to different ambient lighting conditions and user preferences, providing a more comfortable and personalized visual experience. At the same time, the brightness adjustability also helps to save energy and extend the battery life of the device.

[0024] It should be noted that in the specific selection of light source 4, although white light LED is a common choice, other types of self-luminous structures can also be used according to specific application scenarios and design requirements, such as OLED (organic light-emitting diode), miniLED (micro light-emitting diode) and microLED (micro light-emitting diode, smaller in size). These different types of self-luminous structures have their own characteristics in size, performance and application scenarios, but can meet the requirements of wavelength range covering the visible light spectrum, thereby ensuring a rich and colorful display effect.

[0025] Furthermore, the collimating microlens 3 is a micron-sized lens with a focusing effect, which can effectively guide the light accurately to the target area, further reduce the scattering and loss of light, and thus improve the display quality. This design ensures that the light emitted by each single pixel structure can form a clear and sharp image or information in space, effectively avoiding blurring or distortion of the image.

[0026] The present invention also provides a near-eye display method based on MEMS technology, comprising the following steps: S1. When the light source 4 emits light, the collimating microlens 3 is responsible for collimating and focusing the light to ensure that the light is output at a specific angle and intensity; S2, MEMS Fabry-Perot cavity structure 2 adjusts the wavelength and phase of the outgoing light according to the control signal, thereby realizing color display and image construction; S3. By adjusting the brightness of the light source 4 in each single pixel structure and the parameters of the MEMS Fabry-Perot cavity structure 2, the image and color of the entire display area can be precisely controlled.

[0027] The angle of the light beam emitted by the light source 4 in step S1 includes selecting a flexible transparent material as the base material, and bonding the flexible screen to a transparent glass lens with a specific radius, so that each pixel point fits the surface structure to form a structure perpendicular to the center of the lens, or placing a parallel structure reflector at the front end of the transparent screen, and the inside of the reflector is coated with reflective films of different angles at regular intervals, so that the emitted parallel light beams become parallel light beams of different angles after passing through the reflector.

[0028] In step S2, the MEMS Fabry-Perot cavity structure 2 adjusts the wavelength and phase of the outgoing light according to the control signal, which uses the light to reflect back and forth between the two reflectors to form a fixed phase difference so that the formula m*λ=2*n is satisfied. gap The light wave λ of *h*cos(α) forms interference effect outside the cavity and passes through, where m is the order, n is gap is the refractive index of the medium inside the Fabry-Perot cavity, h is the thickness of the gap between the two reflectors of the Fabry-Perot cavity, and α is the incident angle of the light beam entering the Fabry-Perot cavity. By controlling the gap thickness h of the Fabry-Perot cavity or the refractive index n of the intermediate medium, gap To achieve the purpose of changing the output wavelength.

[0029] In step S3, the single pixel structure is set to a square area with a side length of D, and is distributed on the surface of the lens in a parallel structure to form a two-dimensional (x, y) area array display structure. The center of each pixel structure is an opaque imaging area composed of a square area with a side length of d, and the area outside the area is a transparent area without any element blocking. By adjusting the size of the imaging area relative to the pixel area, the transparency of the display screen can be selectively adjusted.

[0030] When the single pixel structure is displayed near the eye in step S3, the collimating microlens 3 is placed at a position L3 away from the light source 4, with a focal length of f1, and the image plane B of the light source 4 is focused at a position L1 in front of the eyeball to form a virtual image B', and B' is then imaged B'' through the lens of the eyeball; and the position L1 of the virtual image plane from the eyeball is optimized according to the following formula: 1 / L3-1 / (L1-L4)=1 / f1 1 / L1+1 / L2=1 / f2 Among them, L2 is the image distance from the image plane in the eye to the lens, L4 is the distance from the lens surface to the eyeball, and f2 is the focal length of the human eye lens. In order to enable pixels at different positions to form images at the corresponding positions of the eyeball, the emission angle of each pixel point needs to be determined according to its position away from the center. The emission angle of the nth pixel point from the center is expressed as: Β(n)=arctan(n*D / L4) Using this method, the field of view of the system is twice the angle of incidence corresponding to the edge pixel point, that is: FOV=2*p Among them, p is the emission angle corresponding to the edge pixel.

[0031] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which are equivalent modifications and improvements made to the above embodiments based on the essential technology of the present invention, and all of them belong to the protection scope of the present invention.

Claims

1. A near-eye display structure based on MEMS technology, characterized in that: include: A plurality of single pixel structures with a certain degree of transparency, each single pixel structure comprising a transparent substrate (1), a light source (4), a collimating microlens (3) and a MEMS Fabry-Perot cavity structure (2); Wherein, the collimating microlens (3) comprises: A first light incident surface (31) for receiving central light from the light source (4) and guiding the central light into the interior of the collimating microlens (3); A first light output surface (32), corresponding to the first light incident surface (31), and used to output the refracted central light in a parallel form; A second light incident surface (33), symmetrically located on both sides of the first light incident surface (31), for receiving edge light from the light source (4) and guiding the edge light into the interior of the collimating microlens (3); A side surface (35) for totally reflecting edge light that enters the interior of the collimating microlens (3) after being refracted by the second light incident surface (33), so as to change the transmission path of the light; The second light-emitting surfaces (34) are symmetrically located on both sides of the second light-incident surface (33) and are adjacent to the side surfaces (35), and are used to output the edge light after total reflection in the form of a preset angle.

2. A near-eye display structure based on MEMS technology according to claim 1, characterized in that: The transparent substrate (1) is made of a bendable plastic material or an inflexible rigid material, wherein the bendable plastic material includes PEN or PET, and the inflexible rigid material includes hard plastic or glass.

3. The near-eye display structure based on MEMS technology according to claim 1, characterized in that: The light source (4) is a self-luminous structure, the wavelength range of which covers the spectral band of visible light, and the brightness of the light source can be controlled by adjusting the current or voltage.

4. The near-eye display structure based on MEMS technology according to claim 1, characterized in that: The collimating microlens (3) is a lens of micrometer size with a focusing function.

5. A near-eye display method based on MEMS technology, applied to a near-eye display structure based on MEMS technology as claimed in claim 1, characterized in that: The following steps are involved: S1. When the light source (4) emits light, the collimating microlens (3) is responsible for collimating and focusing the light to ensure that the light is output at a specific angle and intensity; S2, MEMS Fabry-Perot cavity structure (2) adjusts the wavelength and phase of the emitted light according to the control signal, thereby realizing color display and image construction; S3. By adjusting the brightness of the light source (4) in each single pixel structure and the parameters of the MEMS Fabry-Perot cavity structure (2), the image and color of the entire display area can be precisely controlled.

6. The near-eye display method based on MEMS technology according to claim 5, characterized in that: The angle of the light beam emitted by the light source (4) in step S1 includes selecting a flexible transparent material as a base material, and laminating the flexible screen on a transparent glass lens with a specific radius, so that each pixel point is laminated to the surface structure to form a structure perpendicular to the center of the lens, or placing a parallel structure reflector at the front end of the transparent screen, and coating the reflective film with different angles at regular intervals inside the reflector, so that the emitted parallel light beam becomes parallel light beams with different angles after passing through the reflector.

7. The near-eye display method based on MEMS technology according to claim 5, characterized in that: In step S2, the MEMS Fabry-Perot cavity structure (2) adjusts the wavelength and phase of the outgoing light according to the control signal, which uses the light to reflect back and forth between the two mirrors to form a fixed phase difference so that the formula m*λ=2*n is satisfied. gap The light wave λ of *h*cos(α) forms interference effect outside the cavity and passes through, where m is the order, n is the gap is the refractive index of the medium inside the Fabry-Perot cavity, h is the thickness of the gap between the two reflectors of the Fabry-Perot cavity, and α is the incident angle of the light beam entering the Fabry-Perot cavity. By controlling the gap thickness h of the Fabry-Perot cavity or the refractive index n of the intermediate medium, gap To achieve the purpose of changing the output wavelength.

8. The near-eye display method based on MEMS technology according to claim 5, characterized in that: In step S3, the single pixel structure is set to a square area with a side length of D, and is distributed on the surface of the lens in a parallel structure to form a two-dimensional (x, y) area array display structure. The center of each pixel structure is an opaque imaging area composed of a square area with a side length of d, and the area outside the area is a transparent area without any element blocking. By adjusting the size of the imaging area relative to the pixel area, the transparency of the display screen can be selectively adjusted.

9. The near-eye display method based on MEMS technology according to claim 5, characterized in that: In step S3, when the single pixel structure is displayed near the eye, the collimating microlens (3) is placed at a position L3 away from the light source (4), with a focal length of f1, and the image plane B of the light source (4) is focused at a position L1 in front of the eyeball to form a virtual image B', and B' is then imaged B'' through the lens of the eyeball; and the position L1 of the virtual image plane from the eyeball is optimized according to the following formula: 1 / L3-1 / (L1-L4)=1 / f1 1 / L1+1 / L2=1 / f2 Among them, L2 is the image distance from the image plane in the eye to the lens, L4 is the distance from the lens surface to the eyeball, and f2 is the focal length of the human eye lens. In order to enable pixels at different positions to form images at the corresponding positions of the eyeball, the emission angle of each pixel needs to be determined according to its position away from the center.

10. The near-eye display method based on MEMS technology according to claim 9, characterized in that: The emission angle of the nth pixel from the center is expressed as: Β(n)=arctan(n*D / L4) Using this method, the field of view of the system is twice the angle of incidence corresponding to the edge pixel point, that is: FOV=2*p Among them, p is the emission angle corresponding to the edge pixel.

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