Lens group forming highly-uniform rectangular focusing halo, and method for adjusting halo dimension thereof

Abstract

A lens group forming a highly-uniform rectangular focusing halo, comprising: a first lens and a second lens neighboring same. The first lens comprises a first incident surface, a first aspheric surface and a first convex array light-emitting surface, the first convex array light-emitting surface being an array of a plurality of aspheric convex surfaces having rectangular openings; the second lens comprises a second concave array incident surface and a second aspheric light-emitting surface, the second concave array incident surface having an array of a plurality of aspheric concave surfaces having rectangular openings corresponding to the first convex array light-emitting surface. The lens group provided by the present invention allows light rays simply passing through one total internal reflection lens and one plano-convex lens to focus energy into a halo, and keeps ultrahigh optical efficiency.

Description

Lens assembly with highly uniform rectangular focusing halo and method for adjusting halo size thereof Technical Field

[0001] The invention relates to a lens group, in particular to a lens group with highly uniform rectangular focusing halo and a method for adjusting the halo size. Background Art

[0002] In recent years, newer exposure systems have primarily used light-emitting diodes (LEDs) as their light source. However, LED light is highly divergent, and most current exposure systems still rely on traditional methods of collecting light from mercury or halogen lamps. These systems utilize conventional parabolic mirrors, which are not only bulky but also have limited light collection efficiency.

[0003] In existing exposure systems, most designs can only converge and focus the light from the light source into a circular halo close to the target size, barely meeting the uniformity requirement. However, most of the energy is unused outside the rectangular target surface. Even when collecting light, much of the light does not enter the system. Furthermore, a few projection mechanism designs have achieved good optical utilization and uniformity, but the entire system generally requires at least four lenses, which affects the overall optical path length and assembly tolerance. The use of redundant optical components also increases the system size, costs, and reduces light extraction efficiency.

[0004] Summary of the Invention

[0005] To address the issues of bulky, high-cost, and easily lost light extraction efficiency in existing exposure systems, the present invention provides a lens assembly with a highly uniform rectangular focus halo, comprising: a first lens and an adjacent second lens, wherein:

[0006] The first lens comprises a first light incident surface, a first aspheric surface, and a first convex array light exit surface; wherein the first light incident surface comprises a light source focus, and the first convex array light exit surface is an array of several aspheric convex surfaces with rectangular openings; and

[0007] The second lens includes a second concave array light incident surface and a second aspheric light exit surface; wherein the second concave array light incident surface has a plurality of aspheric concave arrays with rectangular openings corresponding to the first convex array light exit surface.

[0008] Wherein, the first lens is preferably a total reflection lens.

[0009] The curvature radius of each aspheric convex or concave array with rectangular openings is between -1 mm and -10 mm, or preferably between -4 mm and -10 mm.

[0010] The curvature radius of the second aspherical light-emitting surface is between -10 mm and -100 mm, or preferably between -30 mm and -100 mm.

[0011] The lens assembly is made of a plastic material or a glass material. The plastic material includes polymethyl methacrylate, polycarbonate, polystyrene, polyethylene, cycloolefin polymer, cycloolefin copolymer, or epoxy resin. The glass material includes flint glass, crown glass, quartz glass, calcium fluoride glass, or fused silica glass.

[0012] The present invention further provides a method for adjusting the halo size of the lens assembly, the steps comprising:

[0013] Providing the above-mentioned lens assembly with highly uniform rectangular focusing halo;

[0014] The parameters of the lens assembly having a highly uniform rectangular focusing halo are adjusted according to the following equations (1) and (2);

[0015] A light source L enters the first light incident surface from the light source focus on the first light incident surface, is collimated by the first lens, is emitted from the first convex array light exit surface, and is projected onto the second concave array light incident surface to be split, and finally is focused onto the projection plane by the second aspherical light exit surface, forming the rectangular focused halo with adjustable size;

[0016] Among them, in formula (1) and formula (2):

[0017] r1 is the curvature radius of the aspheric convex array with rectangular openings in the light-emitting surface of the first convex array;

[0018] r2 is the curvature radius of the aspheric concave surface array, each having a rectangular opening, in the light incident surface of the second concave surface array;

[0019] r3 is the curvature radius of the second aspherical light-emitting surface;

[0020] The distance between the first lens and the second lens is 2 times r1;

[0021] The distance between the rectangular focusing halo position and the second aspheric light-emitting surface is 2 times r3;

[0022] aw and ah are respectively the length and width of the aspheric arrays each having a rectangular opening on the light-emitting surface of the first convex array and the light-incident surface of the second concave array; and

[0023] w and h are the sizes of the resulting rectangular focusing halo.

[0024] In the aforementioned method, the light source includes visible light or ultraviolet light; when the light source is visible light, the material of the lens group with a highly uniform rectangular focusing halo includes plastic material or glass material; when the light source is ultraviolet light, the material of the lens group with a highly uniform rectangular focusing halo includes glass material.

[0025] From the above description, it can be seen that the present invention has the following beneficial effects and advantages:

[0026] The lens assembly provided by this invention allows a light source to focus its energy through only one internal total reflection lens and one plano-convex lens, while maintaining ultra-high optical efficiency. An array of aspherical surfaces with rectangular openings, designed on the light-exiting surface of the internal total reflection lens and the light-entering surface of the plano-convex lens, simultaneously shapes the focused light and produces a uniformly focused halo with a rectangular shape identical to the openings of the array of aspherical surfaces.

[0027] The present invention uses an internal total reflection lens, which is particularly suitable for collecting ultraviolet light and light-emitting diode (LED) light, and parallelizing the light to achieve high optical efficiency. It is then paired with a plano-convex lens to focus the light. Since the internal total reflection lens and the plano-convex lens are both solid transparent objects, an array of aspherical surfaces with rectangular openings can be directly manufactured on the light-emitting surface of the internal total reflection lens and the light-incident surface of the plano-convex lens. The two optical components can directly complete the functions of light collection, collimation and light shaping at the same time to obtain a rectangular and uniform focused halo and achieve high optical efficiency.

[0028] The lens system proposed in this invention, which simultaneously converges and focuses light and shapes it, can also collimate light from divergent light sources like light-emitting diodes (LEDs) with high optical efficiency when used in conjunction with an internal total reflection lens. By utilizing an array of concave and convex surfaces on the light-exiting surface of the internal total reflection lens and the light-entering surface of a plano-convex lens, this system can save one or two lenses compared to traditional systems. After light output, this system is paired with a digital micromirror device (DMD) system, making it suitable for use in small-scale DLP projection systems or maskless exposure systems. This technology has the potential to reduce the size of the projection system and directly adjust the focus halo to the size and shape of the DMD, reducing energy loss caused by the shape mismatch between the focus halo and the DMD. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of the present invention and are not intended to limit the technical scope of the present invention. Unless otherwise apparent from the context or otherwise specified, the same reference numerals in the figures represent the same structure or operation. Among them:

[0030] FIG1 is a schematic diagram of a preferred embodiment of a lens assembly with highly uniform rectangular focusing halo according to the present invention.

[0031] FIG2 is a schematic diagram of the light path of the lens assembly of the present invention.

[0032] Figures 3-1 to 3-8, Figures 4-1 to 4-8, Figures 5-1 to 5-8, Figures 6-1 to 6-8, and Figures 7-1 to 7-8 are rectangular focusing halo images of different sizes obtained by using different r1, r2, and r3 in the present invention.

[0033] FIG8 is a diagram showing the light field distribution of an embodiment of the present invention having the best performance.

[0034] Explanation of symbols:

[0035] 10. First lens

[0036] 11 First light incident surface

[0037] 111 Light source focus

[0038] 12 First aspheric surface

[0039] 13. First convex array light-emitting surface

[0040] 131 Aspheric convex array with rectangular openings

[0041] 20 Second lens

[0042] 21 Second concave array light incident surface

[0043] 211 Aspheric Concave Array with Rectangular Openings

[0044] 22 Second aspherical light-emitting surface

[0045] 30 Projection Plane

[0046] 40 Rectangular Focus Halo

[0047] L light source DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying 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 making creative efforts shall fall within the scope of protection of the present invention.

[0049] The present invention will be described in further detail below with reference to the accompanying drawings:

[0050] The present invention will be technically illustrated and described in detail below with several preferred embodiments. The accompanying drawings are merely some exemplary representations or embodiments of the present invention. For those skilled in the art to which the present invention belongs, the present invention can also be applied to other similar situations based on these drawings without making any further effort.

[0051] The terms "system", "device", "unit" and / or "module" used in the present invention below are a method for distinguishing different components, assemblies, parts, parts or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions. As shown in the present invention, unless the context clearly indicates an exception, the words "a", "an", "a" and / or "the" do not specifically refer to the singular, but may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list, and the method or device may also include other steps or elements.

[0052] Flowcharts are used in this disclosure to illustrate the operations performed by systems according to embodiments of the present invention. It should be understood that the preceding and following operations do not necessarily need to be performed in exact order. Instead, the steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0053] <Lens Assembly with Highly Uniform Rectangular Focusing Vignette>

[0054] Please refer to FIG. 1 , which is a schematic diagram of a preferred embodiment of a lens assembly with a highly uniform rectangular focusing halo according to the present invention. The lens assembly includes a first lens 10 and a second lens 20 disposed adjacent thereto.

[0055] The first lens 10 includes a first light incident surface 11, a first aspheric surface 12, and a first convex array light exit surface 13. The first light incident surface 11 includes a light source focal point 111. The first convex array light exit surface 13 is composed of several aspheric convex arrays 131 with rectangular openings. The radius of curvature of each aspheric array with a rectangular opening is preferably between -1 mm and -10 mm, and more preferably between -4 mm and -10 mm. In the present invention, the first lens 10 is preferably a total internal reflection (TIR) ​​lens.

[0056] The second lens 20 includes a second concave array light entrance surface 21 and a second aspheric light exit surface 22. The second concave array light entrance surface 21 comprises a plurality of aspheric concave arrays 211 with rectangular openings corresponding to the first convex array light exit surface 13. Similarly, the radius of curvature of each aspheric array with rectangular openings on the second concave array light entrance surface 21 is preferably between -1mm and -10mm, more preferably between -4mm and -10mm. The radius of curvature of the second aspheric light exit surface 22 is preferably between -10mm and -100mm, or more preferably between -30mm and -100mm.

[0057] Please refer to Figure 2, which is a light path diagram of the present invention. A light source L enters the first light incident surface 11 through the light source focus 111 on the first light incident surface 11. After being collimated by the first lens 10, it is emitted from the first convex array light exit surface 13 and enters the second concave array light incident surface 21, where it is split. Finally, it is focused by the second aspherical light exit surface 22 onto a projection plane 30, forming a rectangular focused halo 40.

[0058] <How to adjust the size of the rectangular focus halo>

[0059] The present invention provides a method for adjusting the size of the rectangular focusing halo 40 corresponding to the lens assembly, the steps of which include:

[0060] Step 1: providing the lens assembly having a highly uniform rectangular focusing halo;

[0061] Step 2: Adjust the parameters of the lens assembly with highly uniform rectangular focusing halo according to the following equations (1) and (2):

[0062] in:

[0063] In formula (1) and formula (2), r1 is the curvature radius of the aspheric arrays each having a rectangular opening in the first convex array light-emitting surface 13;

[0064] r2 is the curvature radius of the aspheric array having rectangular openings in the second concave array light incident surface 21;

[0065] r3 is the curvature radius of the second aspherical light-emitting surface 22;

[0066] The distance between the first lens 10 and the second lens 20 is 2 times r1;

[0067] The distance between the rectangular focusing halo 40 and the second aspherical light emitting surface 22 is 2 times r3;

[0068] aw and ah are respectively the length and width of the aspheric arrays with rectangular openings in the first convex array light emitting surface 13 and the second concave array light incident surface 21;

[0069] w and h are the sizes of the obtained rectangular focusing halo 40 respectively.

[0070] Step 3: The light source L enters the first light incident surface 11 from the light source focus 111 on the first light incident surface 11, is collimated by the first lens 10, is emitted from the first convex array light output surface 13 and is projected into the second concave array light input surface 21 to be split, and finally is focused onto the projection plane 30 by the second aspherical light output surface 22 to form the rectangular focusing halo 40 of adjustable size.

[0071] <Material selection of lenses 10 and 20 and light source L>

[0072] The lens assembly provided by the present invention is primarily made of materials with high light transmittance and low light absorption, and may include plastic (or resin) or glass. Plastic materials include polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polyethylene (PE), cycloolefin polymer (COP), cycloolefin copolymer (COC), and epoxy resin. Glass materials include flint glass, crown glass, silica glass, calcium fluoride glass (CaF2), and fused quartz.

[0073] The light source L (incident light) used in the present invention is mainly a light emitting diode (LED) light source, but may also be visible light (wavelength between 380nm-780nm) to ultraviolet light depending on the material of the lens used.

[0074] When the present invention is applied to applications where the human eye or camera is the primary viewer, such as DLP projectors, backlit panel displays, AR, VR, road lighting, and inspection lighting, to provide illumination light for an object to be measured or illuminated for observation by the human eye or camera, the present invention can use visible light as the incident light and is combined with a lens assembly made of a plastic material (or resin material), such as the aforementioned PMMA, PC, PS, PE, COP, COC, Epoxy, or a glass material, such as Flint Glass, Crown Glass, or quartz glass.

[0075] When the present invention is applied to an exposure machine, such as a maskless exposure machine, due to the relationship between line width requirements and material response, it is preferred to use ultraviolet incident light and a lens assembly made of glass materials such as Silica Glass, CaF2, and Fused Quartz.

[0076] <Validity Test>

[0077] Please refer to Table 1 below, which shows several preferred embodiments of the method of adjusting the size of the rectangular focusing halo 40 using the above-mentioned lens group of the present invention, with a light-emitting diode (LED) as the light source L, including adjusting r1 and r2 between -4mm, -5mm, -6mm, -8mm, -10mm, and r3 between -30mm, -40mm, -50mm, -60mm, -70mm, -80mm, -90mm, -100mm. The resulting rectangular focusing halo 40 is of different sizes. At the same time, the relative illumination of each embodiment is based on the ANSI standard, and the minimum value of the halo corner is captured and compared with the maximum value in the center. The illumination values ​​of the four corner points are U1, U2, U3, and U4, respectively, and their positions are 1 / 10 of the distance from the halo corner to the center point. The central illumination is U c , then the relative illumination U r The calculation is performed according to the following formula (3).

[0078] The size ratio of the rectangular focusing halo 40 of the present invention is mainly determined by the aspherical array shape of the rectangular openings of each small optical surface in the array of the first convex array light exit surface 13 and the second concave array light entrance surface 21. At the same time, the relative illumination of the present invention is higher than 60%.

[0079] Table 1

[0080] Please refer to Table 2. According to the 13-point illumination uniformity calculation method proposed by the American National Standards Institute (ANSI), the uniformity of each rectangular focusing halo provided by the present invention reaches an extremely high performance of at least 80%.

[0081] Table 2

[0082] Please refer to the following Table 3 and the light field distribution diagram of FIG8 , which are the best performing embodiments of the present invention with r1 and r2 being -10 mm, and r3 being -70 mm, capable of generating a rectangular focusing halo with 96% light uniformity at the light half angle.

[0083] Table 3

[0084] The present invention proposes a light-emitting diode (LED) focusing projection system with light shaping. The system consists of an internal total reflection lens and a convex lens. The light-emitting surface of the internal total reflection lens is composed of numerous identical small convex surfaces, while the light-entering surface of the convex lens is composed of numerous identical small concave surfaces. Each small convex surface and each small concave surface have the same rectangular light-emitting aperture, and are mutually opposed. This projection system collimates the divergent light from the LED through the internal total reflection lens. The light energy is then split, shaped, and focused by the convex lens, and then superimposed on a screen in front of the convex lens, producing a highly uniform rectangular focused halo.

[0085] <Application Areas>

[0086] 1. Digital Light Processor (DLP): A key component in a DLP projector is the Digital Micromirror Device (DMD), which serves as the projector's image source. An optical system is required in front of the DMD to provide a uniform light source. Standards require a light uniformity of at least 80% and a light half-angle within 12°. According to the table above, the uniformity and light half-angle performance of each embodiment of the present invention meet these requirements.

[0087] 2. Maskless Exposure Machine: The key component of a maskless exposure machine is also the DMD, so it also requires an optical system to provide lighting. In industrial processes, efficiency is important, and it is crucial to effectively focus the energy emitted by the light source on the target. The high light uniformity performance of the various embodiments of the present invention can meet this application.

[0088] 3. Rear-projection displays: Displays require uniform illumination to maintain image quality. Using a diffuser can also achieve uniformity, but most of the energy will be absorbed, and often some energy will exceed the display range. The present invention can project a halo with high light uniformity to improve the above-mentioned energy loss problem.

[0089] 4. Road lighting: Road lighting requires effective control of light sources within a target range. This is primarily for efficiency reasons, but also to avoid dangerous light exposure to pedestrians' eyes. Uniform lighting is also required to improve road quality. This is not limited to streetlights and can also be applied to vehicle lights. The present invention can project a focused, highly uniform halo for excellent lighting applications.

[0090] 5. Inspection Lighting: In general industrial inspections, even microscopic observations, uniform illumination is required to help maintain measurement accuracy. The present invention can project a focused and highly uniform halo for excellent lighting applications.

[0091] 6. Augmented Reality (AR) and Virtual Reality (VR): Near-eye displays require both brightness and uniformity to ensure clear virtual images while viewing the real world. Effective light utilization not only provides a sufficiently bright light source but also avoids burdening the light source. This invention is not limited by aperture size and has the capability to be applied in near-eye displays.

[0092] In some embodiments of the above description, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present invention are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0093] Finally, it should be understood that the embodiments described herein are intended only to illustrate the principles of the present invention. Other variations are also possible and fall within the scope of the present invention. Therefore, by way of example and not limitation, alternative configurations of the embodiments of the present invention may be considered consistent with the teachings of the present invention. Accordingly, the embodiments of the present invention are not limited to the embodiments explicitly described and illustrated herein.

Claims

1. A lens group with a highly uniform rectangular focusing halo, comprising: a first lens and a second lens disposed adjacent thereto, characterized in that, The first lens includes a first incident light surface, a first aspherical surface, and a first convex surface array exit surface; wherein, a light source focus is included on the first incident light surface, and the first convex surface array exit surface is an aspherical convex surface array with a plurality of rectangular openings; and The second lens includes a second concave surface array incident light surface and a second aspherical exit surface; wherein, the second concave surface array incident light surface has a plurality of aspherical concave surface arrays with rectangular openings corresponding to the first convex surface array exit surface.

2. The lens group with a highly uniform rectangular focusing halo according to claim 1, characterized in that, The radius of curvature of each aspherical convex or concave surface array with a rectangular opening ranges from -1 mm to -10 mm.

3. The lens group with a highly uniform rectangular focusing halo according to claim 2, characterized in that, The radius of curvature of each aspherical convex or concave surface array with a rectangular opening ranges from -4 mm to -10 mm.

4. The lens group with a highly uniform rectangular focusing halo according to claim 1, 2 or 3, characterized in that, The first lens is a total reflection lens.

5. The lens group with a highly uniform rectangular focusing halo according to claim 1, 2 or 3, characterized in that, The radius of curvature of the second aspherical exit surface ranges from -10 mm to -100 mm.

6. The lens group with a highly uniform rectangular focusing halo according to claim 1, 2 or 3, characterized in that, The radius of curvature of the second aspherical exit surface ranges from -30 mm to -100 mm.

7. The lens group with a highly uniform rectangular focusing halo according to claim 1, 2 or 3, characterized in that, The material of the lens group includes plastic material or glass material.

8. The lens group with a highly uniform rectangular focusing halo according to claim 7, characterized in that, The plastic material includes polymethyl methacrylate, polycarbonate, polystyrene, polyethylene, cycloolefin polymer, cycloolefin copolymer, or epoxy resin; and the glass material includes flint glass, crown glass, fused quartz glass, calcium fluoride glass, or fused silica glass.

9. A method for adjusting the halo size of a lens group with a highly uniform rectangular focusing halo, characterized in that, Comprising: Provided is a lens group with a highly uniform rectangular focusing halo as described in any one of claims 1 to 8; Adjust the parameters of the lens group with the highly uniform rectangular focusing halo according to the following formulas (1) and (2); A light source enters the first incident light surface from the light source focus on the first incident light surface, after being collimated by the first lens, exits from the first convex surface array exit surface and is projected onto the second concave surface array incident light surface It splits, and finally is focused by the second aspherical light-emitting surface onto the projection plane to form the rectangular focused light halo with adjustable size; Wherein, in formulas (1) and (2): r1 is the radius of curvature of each aspherical convex surface array with a rectangular opening in the first convex surface array exit surface; r2 is the radius of curvature of each aspherical concave surface array with a rectangular opening in the second concave surface array incident light surface; r3 is the radius of curvature of the second aspherical exit surface; The distance between the first lens and the second lens is 2 times r1; The distance between the position of the rectangular focusing halo and the second aspherical exit surface is 2 times r3; aw and ah are respectively the length and width of each aspherical array with a rectangular opening in the first convex surface array exit surface and the second concave surface array incident light surface; and w and h are respectively the dimensions of the obtained rectangular focusing halo.

10. The method for adjusting the halo size of a lens group with a highly uniform rectangular focusing halo according to claim 9, characterized in that, Comprising: The light source includes visible light or ultraviolet light; when the light source is visible light, the material of the lens group with the highly uniform rectangular focusing halo includes plastic material or glass material; when the light source is ultraviolet light, the material of the lens group with the highly uniform rectangular focusing halo includes glass material.

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