TWI220699B - Two-piece diffractive/refractive compound imaging system - Google Patents

Abstract

The present invention provides two-piece diffractive/refractive compound imaging system, which comprises a first lens and a second lens. The first lens has a concave surface and convex surface, and the concave surface is an object surface. The second lens has a concave surface and convex surface, wherein the convex surface faces to the convex surface of the first lens, and the concave surface faces to a filter. Any surface of the first lens and second lens can be a spherical surface or general non-spherical surface. The imaging system comprises a diffractive surface, wherein the diffractive/refractive compound lens surface can be located at any surface of the first lens and second lens. With the specific optical characteristic of the diffractive device, it is able to eliminate more aberration and increase image quality without increasing the number of devices, thereby achieving the purposes of reducing cost, saving space and miniaturizing.

Description

1220699 V. Description of the invention (l) [Technical field to which the invention belongs]

The present invention provides a -M system, which is mainly composed of a first transflective / refractive composite imaging system whose object surface system is concave, which comprises: 透镜: lens, ㈣-lens spherical surface or -aspherical surface, and Any of the two surfaces of the two lenses may be one in which the diffraction / refraction complex Λ / Λ does not include a diffractive surface. The surface of the lens is either a lens or a second ^ ^ P ^ unique to 70 pieces of diffraction The optical characteristics can eliminate the contention of the image after the content is increased by 70 pieces, and the aberration and imaging quality can be reduced, so as to achieve the purpose of reducing cost, saving space and miniaturization. [Prior art] For a traditional lens to obtain better imaging quality, the system needs to be achieved by multiple refractive elements, such as a "camera lens system" (Republic of China Patent Publication No. 442685). The camera lens system consists of five Lens element structure, or a "composite lens system" (Republic of China Invention Patent Publication No. 432241), the compound lens system is composed of three lens elements, thus causing an increase in the volume and weight of the system, forming consumer electronics Obstacles to product size reduction. Therefore, in recent years, continuous research and development by various circles has led to the creation of diffractive elements. With diffractive elements, many functions that cannot be achieved by refractive elements can be achieved, such as multifocal and ring focus. The incident wavelength performs functions such as demultiplexing, and in combination with a diffractive element and a refractive element, a better imaging quality can be obtained without increasing the number of system lenses. Please refer to FIG. 1, which is an imaging system combining a diffractive element and a refractive element.

One of the habitual structures, "LENSES FOR ELECTRONIC IMAGING

1220699 V. Description of the invention (2)-SYSTEMS "(U.S. patent US609755 No. 1), the imaging lens is a second lens 2, the first lens i has a convex surface, a surface / 12, and the convex surface 11 is an object surface. The convex surface 21 of the second lens 2 facing the first lens} is a diffractive / refractive composite lens surface, and another convex surface of the second lens 2 faces the charge-coupled element 6, although the convex surface 21 combines the diffractive element and Refractive elements can be obtained without increasing the number of lenses in the system: not Γι; Γ lens 1 has a large curvature, making = difficult to make, and the object surface of the first lens 1 is convex u, depending on e, making the first The lens 1 has a large volume, a thick thickness, and a weight; the invention is based on providing a composite imaging device for the special imaging element of the radiation element. The hair complex into the designer. The present content], in view of Xi's two-piece optical characteristics, can be used in quality. Another image system of Mingzhi, another image system of Mingming, the :: fold :, the main purpose of the invention,: a composite imaging system of refraction / refraction. The number of 'remove more images': is to provide a-system-the curvature of the transmission / refraction lens is small, easy to manufacture is to provide a two-piece object surface is concave, suitable for a large field of view Yet another object is to provide a two-piece diffraction / refraction

Page 7 1220699 V. Description of the invention (3) '"' * ---- f t f Imaging system, which can quickly obtain the required lens parameters according to the required design goals. [Embodiment] The other objects and detailed structure of the present invention will be made clearer by clarification. Of course, the arrangement of the present invention in some other parts may be different, but the selected embodiment is used. In the book, it is explained in detail, and its structure is shown in the drawings. The technical content of the Ming is further disclosed, and the structure of the selected embodiment is shown in the figure. This is for illustration purposes only. It is not limited by this structure. Please refer to FIG. 2 and FIG. 3, a two-piece wound composite imaging system according to the present invention has a system focal length of h, and the basin includes: a first lens 3 having a focal length of ^ and a spreading sound center of 〇1 from ^, The thickness 1 is h, and the object plane 31 has a positive power, that is, ^ >0; the second lens 4 'has a focal length of center, a thickness of t2, and a distance from the first lens 2' has a positive The optical power of f, i.e., the distance between the first lens 3 and the second lens 4 is at least ^ a quarter of a distance, and its characteristics satisfy the following: detailed below, or in another part of this description The author of this patent application for a concave / refractive concave surface, system focal length f with lens 3! ≫ 0f1 / f〇 > 1.5 t1 / f〇 > 0, 5 f2 > 〇d12 / f〇 > 0 . 3

Page 8 1220699 V. Description of the invention (4)

Vf〇 > 0 · 3 In addition, the entrance pupil diameter of the system is dep ′, the diameter of the first lens is Di ′, and the diameter of the second lens is D2, and its characteristics satisfy the following:

Di / Dep > 3 VDep > 1 · 4 According to the above definition, the above boundary conditions can be added when designing a two-piece diffraction / refraction composite imaging system to accelerate the optimization speed and find the best solution for the system. Please refer to the preferred embodiment of the present invention shown in FIG. 2 and FIG. 3. The first lens 3 and the second lens 4 are matched with a filter 5, a charge-coupled element 6, and the field angle of the optical system is 60 degrees. The focal length fQ is 5.5 mm (mm), and other / data is shown in Figure 4. The first lens 3 and the second lens 4 are aspherical. The material can be acrylic, glass, or other Optical material, the first lens has a concave surface 31 and a convex surface 32, the second lens 4 has a convex surface and a concave surface 42, the concave surface 31 of the first lens 3 is the object surface facing the object, and the first—the convex surface 32 of the lens faces the first The convex surface 41 of the two lenses 4 and the concave surface 42 of the second lens 4 face the charge-coupled element 6. The filter 5 is disposed between the concave surface 42 of the second lens 4 and the charge-coupled element 6. = Diffraction / refraction composite lens v on the center surface of the second lens 4 In the example, the surface of the diffraction / refraction composite lens is located on the convex surface of the second lens 4

Vo ^ i For the processing method of the diffractive / refractive compound lens surface, here is an overview ~ Please refer to the third figure A, first use the tool nose radius of about 0 2 ~ Second lens 4: surface 41 shape: sphere

Description of the invention (5) Face 41 ~ 2, although this aspheric surface 41-2 is a temporary helmet, you can also use it as a ^ 'Ya noodle, but in order to prevent the diffraction shape from being cut too much, the 71 will not be too much, so The pig must be batched 4% ~ Mao cut 1 material and a half r, and the shape error of the aspheric surface 41-2 is controlled by the following 'and then the blade radius is less than 0 micron === 8 Diffraction surface 41 ", in order to accurately add jade to a non-angled surface with a vertical difference between belts, the triangle 8 has a vertical edge 81. In this way, the knife 1 κ., Χ working convex surface 41 has Diffraction surface 41 1 and aspheric surface 41-2; the diffractive surface 41J and the non-spherical helmet 14.4. 4¾ «, ι / c. Aspheric surface 41-2 is designed using the Sweater Model Evening table 舢 / 蚯 舢, Bao Ren & non-discussion & diffractive / refraction compound lens surface produced by the machine = aspheric coefficient, combined with other parameters shown in Figure 4, we can get the following number fi = 9 · 〇4mm ti = 3.6mm Di = 7.02mm P〇werl = 〇 · ll〇6 Dep = 2.0mm t = 1.8mm L = 17. 56mm t2 = 2.4mm D2 = 3.23mm Power2 = 〇. 05695 person " other optical characteristics Please refer to Fig. 5 to Fig. 10. As shown in the figure, it can be seen that this embodiment has a fairly good modulation transfer function (MTF) and small field curvature and distortion, and in order to eliminate the chromatic aberration of the system, it is worth emphasizing that The invention can eliminate more aberrations and improve imaging quality without increasing the number of components, and is small in size, light in weight, easy to copy, and low in cost. In consumer electronic products such as video and audio CD players, digital cameras, cameras, The future of tape recorders is becoming thinner and thinner. The invention can solve the problems of traditional optical components. In summary, a two-piece diffraction / refraction composite type

1220699 V. Description of the invention (6) The combination of the concave surface of the imaging system and the surface of the diffraction / refraction compound lens can eliminate more aberrations and improve imaging quality without increasing the number of components. Its industrial applicability and Progressive display should be provided; however, the descriptions and drawings disclosed above are only the preferred embodiments of the present invention. When it cannot be used to limit the scope of the present invention, any structure according to the above description and the scope of the following patent applications Various changes in features and functions, such as the replacement of digital effect elements, should still fall under the scope of the present invention. 〆 In addition, the present invention has not been seen in any public disclosure before the application: Therefore, the present invention case has the invention patent elements of "industrial applicability, new borrowing, and advancement of + =". Allow time for examination and grant patents as early as ^ ^ month

1220699 Schematic description [Schematic description] Figure 1 is a schematic diagram of a conventional diffraction / refraction composite imaging system. FIG. 2 is a schematic diagram of a preferred embodiment of the present invention. FIG. 3 is a light trace diagram of a preferred embodiment of the present invention. FIG. 3 is a schematic diagram of processing of a diffractive / refractive composite lens surface. FIG. 4 is a system parameter table of the preferred embodiment of the present invention. FIG. 5 is a dot diagram of a preferred embodiment of the present invention.

FIG. 6 is a diagram of a 0-degree modulation transfer function according to a preferred embodiment of the present invention. FIG. 7 is a diagram of a 15-degree modulation transfer function according to a preferred embodiment of the present invention. FIG. 8 is a 30 degree modulation transfer function diagram of the preferred embodiment of the present invention. FIG. 9 is a secondary spectrum diagram of the preferred embodiment of the present invention. FIG. 10 is a field curvature and distortion diagram of the preferred embodiment of the present invention. Explanation of drawing numbers: 1- first lens 11- convex 12- concave 2-second lens 21 、 22- convex

3- first lens 3 1 -concave 3 2 -convex 4 -second lens 41-convex

Page 121220699 Brief description of the diagram 41_1-diffractive surface 4 1 _ 2 -aspherical surface 42-concave surface 5 -filter, light sheet 6-charge-coupled element 7- arc-shaped cutter 8- triangle-shaped sharp blade 8 1- Vertical edges f0, L, f2-focal length ti, t2-thickness d12-distance

Di- diameter of the first lens D2- diameter of the second lens DEP-entrance pupil diameter

Page 13

Claims (1)

1220699 6. Scope of patent application 1. A two-piece diffraction / refraction composite imaging system with a system focal length of 'which includes a first lens with a focal length of fl, a thickness of L, and an object surface of which is concave; the second The lens has a focal length of h, a thickness of h, and a distance from the first lens of (112; its characteristics satisfy the following ... f! &0; 0 W1 · 5 νί0 > 0 · 5 f2 > 0 d12 / f〇 > 0 3 t2 / f0 > 0.3 2. ^ Applicable patent Fan jg Item 2] (diffraction / refraction composite imaging: image: system, where the entrance pupil diameter of the system is ~ , The diameter of the first lens and the diameter of the second lens are ~, and its characteristics meet the following: / DEP > 3% / DEP > 1 · 4 images; 'Special two-piece diffraction / refraction described in item 1 Any one of the surfaces of the compound spherical second lens may be a surface. The aspheric surface is 'the aspheric surface' and the imaging system includes at least one diffraction 4. The two-chip image system described in item 3 of the scope of the patent application, wherein, Diffraction / refraction composite chirped mirror & refraction composite type surface can be located in the first transmission 1220699 6. Scope of patent application One of the mirror or the second lens. 5. The two-plate diffraction / refraction composite imaging system described in item 1 of the scope of the patent application, wherein the material of the first lens and the second lens may be acrylic or glass. 6. The two-piece diffraction / refraction composite imaging system described in item 1 of the scope of the patent application, wherein the material of the first lens and the second lens is an optical material other than acrylic or glass. Page 15