CN111856848A

CN111856848A - Micro-projection lens for 0.23-inch chip

Info

Publication number: CN111856848A
Application number: CN202010897418.2A
Authority: CN
Inventors: 郭富; 马志强; 杨清波; 马卫华
Original assignee: Nanyang Nanfang Intelligent Photoelectric Co ltd
Current assignee: Nanyang Nanfang Intelligent Photoelectric Co ltd
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2020-10-30
Anticipated expiration: 2040-08-31
Also published as: CN111856848B

Abstract

The invention provides a micro-projection lens for a 0.23-inch chip, which belongs to the technical field of projection lenses, and the micro-projection lens for the 0.23-inch chip is sequentially provided with the following components in the direction from an object plane to an image plane along an optical axis: first even aspheric lens, second even aspheric lens, first biconcave negative lens, first biconvex lens, meniscus lens, achromatic lens group, second biconvex lens and third biconvex lens, achromatic lens group is including the second biconcave negative lens and the fourth biconvex lens that set gradually. The invention has high resolution and can better meet the market demand.

Description

Micro-projection lens for 0.23-inch chip

Technical Field

The invention belongs to the technical field of projection lenses, and particularly relates to a micro-projection lens for a 0.23-inch chip.

Background

From the first projector to the later optical projector in history, and to the digital projector of today, the development of projection technology to today has not only required that the image effect is clearly and efficiently displayed so simply. With the development of society, a small chip micro projector adopting DLP (digital optical processing technology developed by texas instruments) projection technology appears, and high requirements are put on the performance of a projection lens.

Patent document No. CN105527698A discloses a projection lens of DLP micro projector, which includes an image space and an object space, wherein a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a prism and a DMD are sequentially disposed between the image space and the object space, and a diaphragm is disposed between the second lens and the third lens. This projection lens adopts the structure of anti-telephoto, has guaranteed the telecentric degree of camera lens, and relative aperture is big, and the definition is high, compact structure, small, is applicable to 0.3 cun DMD's projection light path.

Patent document No. CN204515225U discloses a short-focus lens with a 0.7 throw ratio for digital DLP projection display, which includes a lens frame, and an aspheric lens, a first optical objective, a second optical objective, a third optical objective, a cemented objective, a fourth optical objective, and a fifth optical objective are sequentially disposed in the lens frame from a near object side to a far object side, and the short-focus lens has the characteristics of good imaging effect, low distortion rate, high aberration, high chromatic aberration, and high light transmittance. The shell is made of high-quality aluminum alloy and has the characteristics of high temperature resistance, deformation resistance, attractive appearance and the like.

Disclosure of Invention

Based on the defects of the prior art, the technical problem to be solved by the invention is to provide the micro-projection lens for the 0.23-inch chip, which has high resolution and can better meet the market demand.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a0.23 inch chip micro projection lens is provided with the following components in sequence from an object plane to an image plane along an optical axis: first even aspheric lens, second even aspheric lens, first biconcave negative lens, first biconvex lens, meniscus lens, achromatic lens group, second biconvex lens and third biconvex lens, achromatic lens group is including the second biconcave negative lens and the fourth biconvex lens that set gradually.

Further, the effective focal length of the projection lens is 6.26mm, and the aperture value of the lens is F1.7.

Further, the projection lens has an image resolving power under a projection screen of 40 inches to 100 inches as follows: the lens MTF is >50% at a resolution of 93 lp/mm.

Further, the projection ratio of the projection lens for the 0.23DMD chip is 1.2.

Furthermore, the first even-order aspheric lens and the second even-order aspheric lens are made of plastic materials.

Furthermore, the first biconcave negative lens, the first biconvex lens, the meniscus lens, the second biconcave negative lens, the fourth biconvex lens, the second biconvex lens and the third biconvex lens are all made of glass.

The core of micro projection is display photoelectric integrated chip, and DLP technology is one of the more fully developed technologies. The design optimization of the known micro projection lens is determined by a series of performance parameters and structure parameters. Therefore, in the lens design process, the relative parameters such as image height, field angle, focal length, relative aperture and the like are mutually restricted, the final imaging quality is greatly affected, especially the distortion is difficult to control, in addition, a longer rear working distance needs to be reserved when the projection lens is matched with the TIR prism, the control difficulty of the lens length and the off-axis aberration is greatly increased, and therefore, the lens with high imaging quality and compact structure and the distortion meeting the use requirement is difficult to design, for example, in CN015527698, a system adopts nine spherical mirrors, the resolution ratio of which is only 50lp/mm, and the distortion of which is about 0.7%.

Compared with the prior art, the invention has the following beneficial effects:

the projection lens consists of 9 lenses, and the projection lens is sequentially provided with the following components in the direction from an object plane to an image plane along an optical axis: first even aspheric lens, second even aspheric lens, first biconcave negative lens, first biconvex lens, meniscus lens, achromatic lens group, second biconvex lens and third biconvex lens, wherein: the first even-order aspheric lens and the second even-order aspheric lens are combined to minimize chromatic aberration, and the first even-order aspheric lens and the second even-order aspheric lens are made of plastic materials, so that the number of lenses in the structure can be reduced, the size of the maximum aperture and the total length of an optical system are reduced, the weight is reduced, the off-axis aberration can be effectively balanced, the relative aperture of the optical system is improved, and the field angle is enlarged; through the organic combination of the lenses, the obtained projection lens can be used for a 0.23DMD chip, and the resolution of the projection lens under a projection picture of 40 inches to 100 inches is as follows: when the resolution ratio is 93lp/mm, the MTF of the lens is more than 50%, the resolution ratio is high, the lens distortion is small, the absolute value of the distortion in the whole field of view is less than 0.4%, and the market demand can be better met.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings.

FIG. 1 is a diagram of an optical system of the present invention;

FIG. 2 is a 2D view of the optical system of the present invention;

FIG. 3 is a graph of MTF for a 40 inch projection image according to the present invention;

FIG. 4 is a graph of MTF for a 80 inch projection of the lens of the present invention;

FIG. 5 is a graph of MTF for a 100 inch projected image according to the present invention;

FIG. 6 is a graph showing distortion when the projected image is 80 inches;

the lens comprises a lens body, a lens cover and a lens cover, wherein the lens cover is arranged on the.

Detailed Description

In order to better understand the present invention, the following examples are further provided to clearly illustrate the contents of the present invention, but the contents of the present invention are not limited to the following examples. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details.

As shown in fig. 1 to 2, a 0.23-inch micro-projection lens for a chip includes, in order from an object plane to an image plane along an optical axis: first even aspheric lens 1, second even aspheric lens 2, first biconcave negative lens 3, first biconvex lens 4, meniscus lens 5, achromatic lens group, second biconvex lens 8 and third biconvex lens 9, achromatic lens group is including the second biconcave negative lens 6 and the fourth biconvex lens 7 that set gradually.

The effective focal length of the projection lens is 6.26mm, and the aperture value of the lens is F1.7.

As shown in fig. 3-5, the image resolution of the projection lens under a 40-inch to 100-inch projection screen is: the lens MTF is >50% at a resolution of 93 lp/mm.

The projection ratio of the projection lens for the 0.23DMD chip is 1.2.

As shown in fig. 6, the lens distortion is small, and the absolute value of the distortion amount in the entire field of view is less than 0.4%.

The first even-order aspheric lens 1 and the second even-order aspheric lens 2 are made of plastic materials, so that the number of lenses in the structure can be reduced, the size of the maximum aperture and the total length of the optical system are reduced, the weight is reduced, the off-axis aberration can be effectively balanced, the relative aperture of the optical system is improved, and the field angle is enlarged.

The first biconcave negative lens 3, the first biconvex lens 4, the meniscus lens 5, the second biconcave negative lens 6, the fourth biconvex lens 7, the second biconvex lens 8 and the third biconvex lens 9 are all made of glass materials.

To meet the above performance parameter requirements, the following description is further made for the structure parameters of each surface of 9 lenses, each lens having two surfaces and 18 surfaces, and the structure parameters of the lens from left to right are shown in table 1:

TABLE 1 structural parameters of each lens

，

The even aspheric expression is as follows:

，

in the formula, R is curvature radius, H is radial coordinate, the unit of the radial coordinate is the same as the unit of the length of the lens, and K is a conical conic coefficient;

when K is less than-1, the curve of the surface shape of the lens is hyperbolic;

when K = -1, the profile curve of the lens is parabolic;

when K is more than-1 and less than 0, the surface-shaped curve of the lens is an ellipse;

when K =0, the surface curve of the lens is circular;

when K is more than 0, the surface-shaped curve of the lens is oblate;

a to D respectively represent coefficients corresponding to the radial coordinates.

Aspherical surface coefficient:

，

in tables 1 and 2 above:

surface numbers

1 and 2 respectively represent a first surface and a second surface of the first even-order aspherical lens 1;

surface numbers 3 and 4 respectively denote a first surface and a second surface of the second even-order aspherical lens 2;

the surface numbers 5 and 6 respectively indicate the first and second surfaces of the first biconcave negative lens 3;

the

surface numbers

7 and 8 respectively indicate the first and second surfaces of the first biconvex lens 4;

the surface numbers 9 and 10 respectively denote a first surface and a second surface of the meniscus lens 5;

surface numbers 11 and 12 respectively indicate the first surface and the second surface of the second biconcave negative lens 6;

the surface numbers 13 and 14 respectively indicate the first surface and the second surface of the fourth biconvex lens 7;

the surface numbers 15 and 16 respectively indicate the first and second surfaces of the second biconvex lens 8;

surface numbers 17 and 18 respectively denote a first surface and a second surface of the third biconvex lens 9;

the first surface is a surface facing the object surface side, and the second surface is a surface facing the image surface side.

The MTF characteristic map reflects the image quality of the lens from the center to the edge. In the present invention, fig. 3 is a MTF graph of a 40-inch projected image of the lens of the present invention, fig. 4 is a MTF graph of an 80-inch projected image of the lens of the present invention, fig. 5 is a MTF graph of a 100-inch projected image of the lens of the present invention, and fig. 6 is a distortion data graph of an 80-inch projected image of the lens of the present invention.

Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims

1. A0.23 inch chip used micro projection lens, its characteristic is: set up in proper order along the optical axis from the object plane to image plane direction: first even aspheric lens, second even aspheric lens, first biconcave negative lens, first biconvex lens, meniscus lens, achromatic lens group, second biconvex lens and third biconvex lens, achromatic lens group is including the second biconcave negative lens and the fourth biconvex lens that set gradually.

2. The micro-projection lens for 0.23 inch chip of claim 1, wherein: the effective focal length of the projection lens is 6.26mm, and the aperture value of the lens is F1.7.

3. The micro-projection lens for 0.23 inch chip of claim 1, wherein: the image resolving power of the projection lens under a projection picture of 40 inches to 100 inches is as follows: the lens MTF is >50% at a resolution of 93 lp/mm.

4. The micro-projection lens for 0.23 inch chip of claim 3, wherein: the projection ratio of the projection lens for the 0.23DMD chip is 1.2.

5. The micro-projection lens for 0.23 inch chip of claim 1, wherein: the first even-order aspheric lens and the second even-order aspheric lens are made of plastic materials.

6. The micro-projection lens for 0.23 inch chip of claim 1, wherein: the first biconcave negative lens, the first biconvex lens, the meniscus lens, the second biconcave negative lens, the fourth biconvex lens, the second biconvex lens and the third biconvex lens are all made of glass materials.