Superlens for realizing light source expansion

Abstract

The application relates to an ultralens for realizing light expansion of a light source, belonging to the optical element field, which is used for expanding light R1 emitted by an LED light source, and comprises a lower microstructure, a substrate and an upper microstructure, wherein the lower microstructure and the upper microstructure are located on two sides of the substrate; the lower microstructure is close to the LED light source and performs first modulation on light; and the upper microstructure is far away from the LED light source and performs second modulation on light. The ultralens can expand the light emitted by the LED light source, realize greater spot width and cover a larger illumination range.

Description

Technical Field

[0001] This application belongs to the field of optical components, and in particular relates to a superlens for amplifying the light from a light source. Background Technology

[0002] LED (Light-Emitting Diode) is a revolutionary lighting technology with many advantages over traditional light sources (such as incandescent and fluorescent lamps), such as small size, stable light emission, high energy conversion efficiency, ultra-long lifespan, and environmental friendliness. However, the light intensity distribution emitted by LED light sources is usually a Lambertian distribution, resulting in an overly bright center and a narrow beam width on the target surface, which cannot cover a large illumination area. Utility Model Content

[0003] This application provides a superlens for amplifying light from a light source, thereby at least solving the above-mentioned technical problems existing in the prior art.

[0004] This application provides a superlens for amplifying light from a light source. The superlens amplifies the light R1 emitted by an LED light source and includes a lower microstructure, a substrate, and an upper microstructure. The lower and upper microstructures are located on opposite sides of the substrate. The lower microstructure is close to the LED light source and modulates the light for the first time. The upper microstructure is far from the LED light source and modulates the light for the second time.

[0005] In one embodiment, the light emitted by the LED light source satisfies the following formula:

[0006] I = I0cosθ

[0007] Where I0 is the light intensity when incident perpendicularly at 0 degrees, and θ is the divergence angle.

[0008] In one possible implementation, when examining the illuminance distribution on the target plane, there exists a conversion relationship from intensity distribution to illuminance scale, which satisfies the following formula:

[0009]

[0010] Where E is the illuminance at a certain location on the target plane, and R is the distance from the target plane to the light source.

[0011] In one embodiment, the lower microstructure and the upper microstructure are respectively formed by arranging micro-nano structural units of different shapes.

[0012] In one possible implementation, by changing different structural shapes and different structural heights, the amplitude, phase, and polarization characteristics of electromagnetic waves incident on the micro / nano structural unit can be precisely controlled.

[0013] In one embodiment, the structural shape of the micro / nano structure unit is one or more of the following: cylinder, rectangular cylinder, and annular cylinder.

[0014] In one embodiment, the upper and lower microstructures and the upper microstructure have a specific phase distribution φ s1 and φ s2 It satisfies the following formula:

[0015]

[0016] Where n i Let θ be the refractive index of the incident medium. i Let n be the angle of incidence. t Let θ be the refractive index of the exit medium. t Let λ be the emission angle, λ be the wavelength of the light wave, and R be the radial coordinates of the lower and upper microstructures. This represents the phase gradient.

[0017] In one embodiment, the ratio of the expanded light spot width to the LED light source spot width is greater than 2.5. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a superlens for amplifying light from a light source in an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the light amplification process of the superlens for the LED light source in an embodiment of this application;

[0020] Figure 3 This application shows the light intensity distribution curve of the light R1 emitted by the LED light source and a schematic diagram of the light spot when the LED light source directly illuminates the target plane in the embodiment of this application;

[0021] Figure 4 This application embodiment shows the light intensity distribution curve of the light source R3 after being amplified by the superlens and a schematic diagram of the light spot after being amplified by the superlens.

[0022] Figure 5 This is a schematic diagram comparing the illuminance distribution of the light spot when the light emitted by the LED light source directly illuminates the target plane and the light spot after being amplified by the superlens in the embodiments of this application;

[0023] Figure 6 This is a partial schematic diagram of the microstructure in an embodiment of this application;

[0024] Figure 7 This is a schematic diagram of the phase gradient distribution and phase distribution of the microstructure in the embodiments of this application;

[0025] Figure 8This is a schematic diagram of the partial distribution of micro / nano structural units in the embodiments of this application;

[0026] Figure 9 This is a schematic diagram of the freeform lens structure in an embodiment of this application;

[0027] Figure 10 This is a schematic diagram of the light amplification process of the freeform lens on the LED light source in the embodiments of this application;

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. LED light source; 2. Superlens; 20. Substrate; 21. Lower microstructure; 22. Upper microstructure; 201. Micro / nano structure unit; 3. Traditional freeform surface lens; 30. Interior; 31. Inner surface; 32. Outer surface; 4. Target plane. Detailed Implementation

[0030] The present application will now be described in further detail with reference to the accompanying drawings.

[0031] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0032] This application provides a superlens for amplifying the light emitted by an LED light source R1, thereby achieving a wider spot width and covering a larger illumination range.

[0033] The structure of superlens 2 is as follows Figure 1 As shown, the superlens 2 includes a lower microstructure 21, a substrate 20, and an upper microstructure 22. The lower microstructure 21 and the upper microstructure 22 are located on opposite sides of the substrate 20.

[0034] The process of light amplification of LED light source 1 by superlens 2 is as follows: Figure 2 As shown, the lower microstructure 21 is close to the LED light source 1 and modulates the light R1 emitted by the LED light source 1 for the first time. The modulated light R2 travels a certain distance in the substrate 20 and then reaches the upper microstructure 22.

[0035] The upper microstructure 22 is moved away from the LED light source 1, and the light R2 reaching the upper microstructure 22 is modulated a second time to obtain the final outgoing light R3. When the final outgoing light R3 illuminates the target plane 4, the spot width is significantly improved compared to the spot width when the LED light source 1 directly illuminates the target plane 4, and the light amplification ratio (broadened spot width / LED light source spot width) is greater than 2.5.

[0036] like Figure 3 The figure shows the light intensity distribution curve of the light ray R1 emitted by LED light source 1 and the light spot when LED light source 1 directly illuminates the target plane 4. The light intensity distribution curve of the light ray R1 emitted by LED light source 1 is a Lambertian distribution, and its light intensity distribution I satisfies the formula:

[0037] I = I0 cosθ

[0038] Where I0 is the light intensity when incident perpendicularly at 0 degrees, and θ is the divergence angle.

[0039] When examining the illuminance distribution on a target plane, there exists a transformation relationship from intensity distribution to illuminance distribution:

[0040]

[0041] Where E is the illuminance at a certain location on the target plane, and R is the distance from the target plane to the light source.

[0042] Therefore, when the light emitted by the Lambert-type LED light source 1 directly illuminates the target plane 4, the light spot exhibits the characteristic of being too strong in the center.

[0043] like Figure 4 The image shows the light intensity distribution curve of light ray R3 from LED light source 1 after being amplified by superlens 2, and the light spot after amplification by superlens 2. The light intensity in the large-angle portion of the light intensity distribution curve increases significantly, exhibiting a "BatWing" shape, and the size of the amplified light spot also increases significantly. Figure 5 The image shows a comparison of the illuminance distribution of the light spot when the light emitted by the LED light source 1 directly illuminates the target plane 4 and the light spot after being amplified by the superlens 2. If the full width at half maximum (FWHM) is used as the standard for measuring the light spot width, the amplification ratio of the superlens 2 reaches 2.5.

[0044] The lower microstructure 21 and the upper microstructure 22 are formed by arranging micro / nano structural units 201 of different shapes. For example... Figure 6 The diagram shown is a partial schematic of the microstructure.

[0045] The unit size p of the micro / nano structure 201 is on the subwavelength order. When the unit size p is fixed, the amplitude, phase, and polarization characteristics of electromagnetic waves incident on the micro / nano structure unit can be precisely controlled by changing different structural shapes and heights. Specifically, the structural shape of the micro / nano structure unit can be a cylinder, square prism, rectangular prism, or annular prism, etc., and the structural height of the micro / nano structure unit is on the wavelength order. When the structural height is fixed, changing the structural shape of the micro / nano structure unit, such as changing the diameter of the cylinder, can yield different phase responses.

[0046] The lower microstructure 21 and the upper microstructure 22 have a specific phase distribution φ s1 and φ s2 According to the generalized Snell's law, light rays at different positions and angles of incidence will be deflected to different degrees when passing through a specific phase distribution, achieving both primary and secondary modulation of the light. The generalized Snell's law is as follows:

[0047]

[0048] Where n i Let θ be the refractive index of the incident medium. i Let n be the angle of incidence. t Let θ be the refractive index of the exit medium. t Let λ be the emission angle, λ be the wavelength of the light wave, and R be the radial coordinates on the lower microstructure 21 and the upper microstructure 22. This represents the phase gradient. Specifically, the process of solving for the phase gradient using the generalized Snell's law can be obtained by dividing the light source's emission angle and mapping it to different positions on the target surface.

[0049] like Figure 7 The diagram shows the phase gradient distribution and phase distribution of one of the microstructure layers.

[0050] The local distribution of the micro / nano structure unit 201 obtained based on the phase distribution is as follows: Figure 8 As shown.

[0051] A traditional freeform lens 3 can also be used to amplify the light R1 emitted by the LED light source 1, achieving a wider light spot and covering a larger illumination area. The structure of the freeform lens 3 is as follows: Figure 9 As shown, it includes an interior 30, an inner surface 31, and an outer surface 32. The inner surface 31 is called a cannonball cavity lens because its shape resembles a cannonball. The interior 30 of the freeform lens 3 is often made of optical plastics such as PMMA.

[0052] The process of light amplification of LED light source 1 by freeform lens 3 is as follows: Figure 10As shown, the light beam R1 emitted by the LED light source 1 is deflected for the first time after passing through the inner surface 31 of the freeform lens 3. After the first deflection, the light beam R2 travels a certain distance inside the freeform lens 3 3 3 and reaches the outer surface 32 of the freeform lens 3, where it is deflected for the second time. The light beam R3 after the second deflection finally illuminates the target plane 4, forming the target light spot.

[0053] However, traditional freeform surface lenses 3 are typically manufactured using injection molding or similar processes. Their unique surface shape places extremely high demands on the ultra-precision machining of the core mold (e.g., using a single-point diamond lathe), resulting in long processing times, significant technical difficulties, and stringent yield control. The superlens 2 proposed in this embodiment is manufactured using mature integrated semiconductor technology, ensuring both the structural accuracy of the microstructure and a high production yield.

[0054] Furthermore, the freeform lens 3 is typically injection molded from optical plastics such as PMMA or PC. These materials have poor heat resistance and are prone to yellowing and deformation under the heat emitted by the LED light source 1 (especially high-power LEDs) for extended periods. Once the lens deforms, its precise optical performance will be completely lost. The superlens 2 proposed in this embodiment has excellent heat resistance and stability, and will not deform or degrade in performance even under long-term irradiation by the LED light source 1.

[0055] The superlens 2 proposed in this embodiment is a planar optical element. Macroscopically, its upper and lower microstructures 21 and 22 are both planar. Since the thickness of the upper and lower microstructures 21 and 22 is on the order of wavelength of light, the thickness of the superlens is essentially equal to the thickness of the substrate 20. Compared to a traditional freeform lens 3, the thickness of the superlens 2 is less than one-third of the thickness of the freeform lens 3, resulting in a significantly reduced volume and a clear advantage.

[0056] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A superlens for amplifying light from a light source, characterized in that, The superlens is used to amplify the light R1 emitted by the LED light source. It includes a lower microstructure, a substrate, and an upper microstructure, with the lower and upper microstructures located on opposite sides of the substrate. The lower microstructure is close to the LED light source and modulates the light for the first time; The upper microstructure is located away from the LED light source, thus modulating the light a second time.

2. A superlens according to claim 1, characterized in that: The light emitted by the LED light source satisfies the following formula: I = I0cosθ Where I0 is the light intensity when incident perpendicularly at 0 degrees, and θ is the divergence angle.

3. A superlens according to claim 2, characterized in that: When examining the illuminance distribution on a target plane, there exists a conversion relationship from intensity distribution to illuminance scale, which satisfies the following formula: Where E is the illuminance at a certain location on the target plane, and R is the distance from the target plane to the light source.

4. A superlens according to claim 1, characterized in that: The lower and upper microstructures are formed by arranging micro- and nano-structure units of different shapes.

5. A superlens according to claim 4, characterized in that: By changing different structural shapes and heights, the amplitude, phase, and polarization characteristics of electromagnetic waves incident on micro / nano structural units can be precisely controlled.

6. A superlens according to claim 4, characterized in that: The micro / nano structure unit has one or more of the following structural shapes: cylinder, rectangular cylinder, and annular cylinder.

7. A superlens according to claim 1, characterized in that: The upper and lower microstructures and the upper microstructure have a specific phase distribution φ s1 and φ s2 It satisfies the following formula: Where n i Let θ be the refractive index of the incident medium. i Let n be the angle of incidence. t Let θ be the refractive index of the exit medium. t Let λ be the emission angle, λ be the wavelength of the light wave, and R be the radial coordinates of the lower and upper microstructures. This represents the phase gradient.

8. A superlens according to claim 1, characterized in that: The ratio of the beam width after light amplification to the beam width of the LED light source is greater than 2.5.

Images