Reflection type optical encoder chip with metasurface structure

Abstract

The invention provides a reflective optical encoder chip with a metasurface structure, and the chip comprises a light source which is used for transmitting a light beam; the first transparent substrate is arranged above the photoreceptor chip; the second transparent substrate is arranged above the light source; a thin film coating is arranged on the second transparent substrate, gaps are etched in the thin film coating to form a metasurface structure, and the metasurface structure carries out calculation according to light energy distribution of the light beams, so that interference and diffraction of the multiple gaps are achieved, the light beams are emitted in a directional mode, and / or light energy is evenly distributed. According to the reflective optical encoder chip with the metasurface structure, the metasurface structure is formed by coating and etching the plane transparent substrate, the function of a super lens is achieved, customizable optimization is carried out on light beams of a light source, the size is small enough, and the reflective optical encoder chip is well suitable for the reflective optical encoder chip.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a reflective optical encoder chip with a super surface structure. Background Art

[0002] Compared with transmissive optical encoders, reflective optical encoders have the advantages of higher integration, simpler system, smaller overall system volume and thickness. However, reflective optical encoder chips have higher requirements for the optical design of the light source: the light source needs to be protected by the mechanical structure as much as possible, the light source needs to be at the same height as the photoreceptor as much as possible, the light source needs to be as close to the photosensitive area as possible, and the light noise of the light source needs to be minimized.

[0003] The commonly used structures in the industry include: abandoning mechanical protection and leaving the light source exposed; using package windows and adding materials such as silicone to form simple mechanical protection and optical processing; using package windows and adding thinned glass; using processed sapphire and other transparent substrates, etc. Most of these solutions are large in size and have complex packaging processes, and are almost unable to optimize the light beam emitted by the light source. The consistency and directionality of the light beam emitted by the light source are crucial to the accuracy of the reflective optical encoder chip.

[0004] Therefore, it is necessary to provide a reflective optical encoder chip with a metasurface structure to solve the above problems. Summary of the invention

[0005] The present invention provides a reflective optical encoder chip with a metasurface structure. The metasurface structure is formed by coating and etching a planar transparent substrate, thereby realizing the function of a superlens, performing customizable optimization on a light source beam, and having a small enough volume, and being well suitable for a reflective optical encoder chip.

[0006] An embodiment of the present invention provides a reflective optical encoder chip with a metasurface structure, comprising:

[0007] a light source for emitting a light beam;

[0008] A first transparent substrate disposed above the photoreceptor chip;

[0009] a second transparent substrate disposed above the light source;

[0010] A thin film coating is provided on the second transparent substrate, and gaps are etched on the thin film coating. The metasurface structure is calculated according to the light energy distribution of the light beam to achieve interference and diffraction of the porous gaps, so that the light beam is emitted in a direction and / or the light energy is evenly distributed.

[0011] Preferably, the material of the super surface structure is titanium oxide or silicon oxide.

[0012] Preferably, the etching gap of the super surface structure is sub-micron level.

[0013] Preferably, the diameter of the nano-columnar structure of the metasurface structure is proportional to its height, so as to achieve a change in the propagation direction of light of a selected wavelength.

[0014] Preferably, the metasurface structure is calculated according to the light energy distribution of the incident light, specifically according to the following formula:

[0015]

[0016] Among them, θ t ,θ i represents the incident angle and refraction angle of light in two media during propagation, n t and n i represents the refractive index of the two media during light propagation, λ0 represents the wavelength of light in a vacuum, dx represents the distance between the metasurface structures, and dφ represents the offset of the phase mutation in different paths of light propagation.

[0017] Preferably, the light source and the photoreceptor chip are respectively arranged on a substrate, the light source is arranged on one side of the photoreceptor, and the light beam is upward and reflected to the photoreceptor chip through a code disc.

[0018] Preferably, the photoreceptor chip is disposed on a substrate, the light source is disposed on the photoreceptor chip, and the light beam is uniformly emitted upward and is reflected to the photoreceptor chip through a code disk.

[0019] Preferably, the height of the supersurface structure is 400 nm-2 μm.

[0020] Preferably, the height of the metasurface structure is close to the wavelength of the light source, and the gap size of the metasurface structure is close to the wavelength of the light source. The change of the light propagation direction and mode is achieved through the phase mutation in the light propagation direction at the size level of similar wavelength.

[0021] Preferably, it also includes a plastic packaging material, which is used to package the light source, the photoreceptor chip and the substrate.

[0022] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0023] A reflective optical encoder chip with a metasurface structure provided by an embodiment of the present invention comprises: a light source for emitting a light beam; a first transparent substrate disposed above a photoreceptor chip; a second transparent substrate disposed above the light source; a thin film coating is disposed on the second transparent substrate, and slits are etched on the thin film coating to form a metasurface structure, wherein the metasurface structure is calculated according to the light energy distribution of the light beam to achieve interference and diffraction of the porous slits, so that the light beam is emitted in a directional manner and / or the light energy is evenly distributed, and the function of a super lens is achieved by coating a planar transparent substrate, and the light beam of the light source is optimized in a customizable manner, and the volume is small enough, so that it is well suitable for a reflective optical encoder chip;

[0024] Furthermore, the material of the super surface structure is titanium oxide or silicon oxide, which can achieve sub-micron etching gaps;

[0025] Furthermore, the diameter of the nano-columnar structure of the metasurface structure is proportional to the height, so that the propagation direction of light of the selected wavelength is changed, so that the light beam emitted by the light source is uniform and directional. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present invention, not all embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0027] Figure 1 It is a structural schematic diagram of a reflective optical encoder chip in the prior art;

[0028] Figure 2 A schematic structural diagram of a reflective optical encoder chip with a metasurface structure provided by one embodiment of the present invention;

[0029] Figure 3 A schematic diagram of a light source of a reflective optical encoder chip in the prior art emitting an uneven light beam;

[0030] Figure 4 A schematic diagram of a light source of a reflective optical encoder chip with a metasurface structure emitting a uniform and directional light beam provided by an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of the structure of another reflective optical encoder chip in the prior art;

[0032] Figure 6A schematic structural diagram of a reflective optical encoder chip with a metasurface structure provided by another embodiment of the present invention;

[0033] Figure 7 A schematic diagram of another reflective optical encoder chip in the prior art emitting an uneven light beam from a light source;

[0034] Figure 8 A schematic diagram of a light source of a reflective optical encoder chip with a metasurface structure emitting a uniform and directional light beam provided by another embodiment of the present invention;

[0035] Fig. 9 A schematic diagram of light propagation of incident light in a metasurface structure of a reflective optical encoder chip having a metasurface structure provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0038] Based on the problems existing in the prior art, an embodiment of the present invention provides a reflective optical encoder chip with a metasurface structure. The metasurface structure is formed by coating a flat transparent substrate to realize the function of a superlens, and the light source beam is customizable and optimized. The volume is small enough, and it is well suitable for reflective optical encoder chips.

[0039] Figure 1 It is a structural schematic diagram of a reflective optical encoder chip in the prior art; Figure 2 A schematic structural diagram of a reflective optical encoder chip with a metasurface structure provided by one embodiment of the present invention; Figure 3 A schematic diagram of a light source of a reflective optical encoder chip in the prior art emitting an uneven light beam; Figure 4 A schematic diagram of a light source of a reflective optical encoder chip with a metasurface structure emitting a uniform and directional light beam provided by an embodiment of the present invention; Figure 5 It is a schematic diagram of the structure of another reflective optical encoder chip in the prior art; Figure 6A schematic structural diagram of a reflective optical encoder chip with a metasurface structure provided by another embodiment of the present invention; Figure 7 A schematic diagram of another reflective optical encoder chip in the prior art emitting an uneven light beam from a light source; Figure 8 A schematic diagram of a light source of a reflective optical encoder chip with a metasurface structure emitting a uniform and directional light beam provided by another embodiment of the present invention; Fig. 9 A schematic diagram of light propagation of incident light in a metasurface structure of a reflective optical encoder chip having a metasurface structure provided in accordance with an embodiment of the present invention.

[0040] View now Figures 1 to 9 , an embodiment of the present invention provides a reflective optical encoder chip with a metasurface structure, comprising:

[0041] a light source for emitting a light beam;

[0042] A first transparent substrate disposed above the photoreceptor chip;

[0043] a second transparent substrate disposed above the light source;

[0044] A thin film coating is provided on the second transparent substrate, and gaps are etched on the thin film coating to form a super surface structure. The super surface structure is calculated according to the light energy distribution of the light beam to achieve interference and diffraction of the porous gaps, so that the light beam is emitted in a direction and / or the light energy is evenly distributed.

[0045] Specifically, the light source may be a LED (Light Emitting Diode) light source, or a VCSEL (Vertical Cavity Surface Emitting Laser). The metasurface structure may be fabricated on a transparent substrate such as glass or quartz.

[0046] An ordinary optical lens has the function of directional emission of a light beam, but the volume of a reflective optical encoder chip is very small. If an ordinary optical lens is introduced, the reflective optical encoder cannot be accommodated due to its large volume.

[0047] In addition, in the prior art, the working accuracy of the reflective encoder chip is usually improved by processing the photoreceptor chip or processing the signal.

[0048] The reflective optical encoder chip with a metasurface structure provided in the present application realizes the function of a superlens from the perspective of processing the light source by coating and etching a transparent substrate to form a metasurface structure, performs customizable optimization of the light source beam, and is small enough to be well suited for reflective optical encoder chips.

[0049] In a specific implementation, the material of the super surface structure is titanium oxide or silicon oxide. The material of the super surface structure is selected from materials that have less absorption of the light source wavelength and are easy to be processed using semiconductor processing technology, preferably titanium dioxide or silicon dioxide.

[0050] Thus, sub-micron etching gaps can be achieved.

[0051] In a specific implementation, the etching gap of the super surface structure is sub-micron level.

[0052] In a specific implementation, the diameter of the nano-columnar structure of the metasurface structure is proportional to the height, thereby achieving a change in the propagation direction of light of a selected wavelength.

[0053] As a result, the light beam emitted by the light source is made uniform and directional.

[0054] In a specific implementation, the metasurface structure is calculated according to the light energy distribution of the incident light, specifically according to the following formula:

[0055]

[0056] Among them, θ t ,θ i represents the incident angle and refraction angle of light in two media during propagation, n t and n i represents the refractive index of the two media during light propagation, λ0 represents the wavelength of light in a vacuum, dx represents the distance between the metasurface structures, and dφ represents the offset of the phase mutation in different paths of light propagation.

[0057] In a specific implementation, the light source and the photoreceptor chip are respectively arranged on a substrate, the light source is arranged on one side of the photoreceptor, and the light beam is upward and reflected to the photoreceptor chip through the code disk.

[0058] In a specific implementation, the photoreceptor chip is disposed on a substrate, the light source is disposed on the photoreceptor chip, and the light beam is uniformly emitted upward and is reflected to the photoreceptor chip through a code disk.

[0059] In a specific implementation, the height of the supersurface structure is 400nm-2μm.

[0060] In a specific implementation, the height of the metasurface structure is close to the wavelength of the light source, and the gap size of the metasurface structure is close to the wavelength of the light source. The change in the direction and mode of light propagation is achieved through a phase mutation in the direction of light propagation at a size level similar to the wavelength.

[0061] In a specific implementation, a plastic packaging material is also included, which is used to package the light source, the photoreceptor chip, and the substrate.

[0062] In summary, a reflective optical encoder chip with a metasurface structure provided by an embodiment of the present invention includes: a light source for emitting a light beam; a first transparent substrate disposed above a photoreceptor chip; a second transparent substrate disposed above the light source; a thin film coating is disposed on the second transparent substrate, and slits are etched on the thin film coating to form a metasurface structure, the metasurface structure is calculated according to the light energy distribution of the light beam, and interference and diffraction of the porous slits are realized, so that the light beam is emitted in a directional manner and / or the light energy is evenly distributed, and the function of a super lens is realized by coating a planar transparent substrate, and the light beam of the light source is optimized in a customizable manner, and the volume is small enough, so it is well suitable for a reflective optical encoder chip;

[0063] Furthermore, the material of the super surface structure is titanium oxide or silicon oxide, which can achieve sub-micron etching gaps;

[0064] Furthermore, the diameter of the nano-columnar structure of the metasurface structure is proportional to the height, so that the propagation direction of light of the selected wavelength is changed, so that the light beam emitted by the light source is uniform and directional.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reflective optical encoder chip with a metasurface structure, characterized in that: include: a light source for emitting a light beam; A first transparent substrate disposed above the photoreceptor chip; a second transparent substrate disposed above the light source; A thin film coating is provided on the second transparent substrate, and gaps are etched on the thin film coating to form a super surface structure. The super surface structure is calculated according to the light energy distribution of the light beam to achieve interference and diffraction of the porous gaps, so that the light beam is emitted in a direction and / or the light energy is evenly distributed.

2. The reflective optical encoder chip with a metasurface structure according to claim 1, characterized in that: The material of the super surface structure is titanium oxide or silicon oxide.

3. The reflective optical encoder chip with a metasurface structure according to claim 2, characterized in that: The etching gap of the super surface structure is sub-micron level.

4. The reflective optical encoder chip with a metasurface structure according to claim 3, characterized in that: The diameter of the nano-columnar structure of the super surface structure is proportional to the height, so that the propagation direction of light of the selected wavelength can be changed.

5. The reflective optical encoder chip with a metasurface structure according to claim 4, characterized in that: The metasurface structure is calculated according to the light energy distribution of the incident light, specifically according to the following formula: Among them, θ t ,θ i represents the incident angle and refraction angle of light in two media during propagation, n t and n i represents the refractive index of the two media during light propagation, λ0 represents the wavelength of light in a vacuum, dx represents the distance between the metasurface structures, and dφ represents the offset of the phase mutation in different paths of light propagation.

6. The reflective optical encoder chip with a metasurface structure according to claim 1, characterized in that: The light source and the photoreceptor chip are respectively arranged on a substrate, the light source is arranged on one side of the photoreceptor, and the light beam is directed upward and is reflected to the photoreceptor chip through a code disc.

7. The reflective optical encoder chip with a metasurface structure according to claim 1, characterized in that: The photoreceptor chip is arranged on the substrate, the light source is arranged on the photoreceptor chip, and the light beam is uniformly emitted upward and reflected to the photoreceptor chip through the code disk.

8. The reflective optical encoder chip with a metasurface structure according to claim 1, characterized in that: The height of the super surface structure is 400nm-2μm.

9. The reflective optical encoder chip with a metasurface structure according to claim 1, characterized in that: The height of the metasurface structure is close to the wavelength of the light source, and the gap size of the metasurface structure is close to the wavelength of the light source. The change of the light propagation direction and mode is achieved through the phase mutation in the light propagation direction at a size level similar to the wavelength.

10. The reflective optical encoder chip with a metasurface structure according to claim 6 or 7, characterized in that: It also includes a plastic packaging material, which is used to package the light source, the photoreceptor chip, and the substrate.

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