LCOS-based small-format projection lens and projector

Abstract

The invention provides an LCOS-based small-format-size projection lens and projector, and belongs to the technical field of optical lenses, the LCOS-based small-format-size projection lens comprises a front group and a rear group which are coaxially and sequentially arranged from the projection screen side to the LCOS chip side along the light direction, and a diaphragm is arranged between the front group and the rear group; the front group comprises an aspherical lens with negative diopter, a first negative meniscus lens, a second negative meniscus lens and a positive meniscus lens which are coaxially arranged in sequence; and the rear group comprises a first bonding lens, a second bonding lens, a positive diopter aspherical lens and a biconvex lens which are coaxially arranged in sequence. The projection lens is short in projection distance, high in resolving power, high in resolution ratio, small in size and compact in structure, the cost of the projection lens is reduced, and market requirements can be well met.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a small-format projection lens and a projector based on LCOS. Background Art

[0002] Projection technology is widely used in daily work and life. With the development of emerging technologies, users are pursuing high resolution, high resolution and high fidelity of projection images. At the same time, emerging technologies are maturing in development, and existing projection lenses cannot meet users' needs for some special scenes. Therefore, a small-format projection lens based on LCOS was developed and applied.

[0003] LCOS is a combination of liquid crystal display technology and CMOS traditional semiconductor technology. Compared with LCD projection technology and DLP projection technology, LCOS projection technology has the characteristics of high aperture ratio and high resolution. At the same time, due to the small distance between pixels of LCOS chip, the projected picture will be more realistic.

[0004] The patent document with publication number CN 103176262 A discloses a full-spherical high-definition LCOS lens suitable for 1920×1080 single-chip LCOS. The lens is composed of eight spherical lenses, with a focal length of 19.24mm, F#1.7, a projection ratio of 1.8, and a spatial cutoff frequency of 60lp / mm@MIF value greater than 0.5. However, the projection ratio of the lens is large, and a long projection distance is required to realize the demand for projecting a small screen, which is not suitable for the trend of product miniaturization.

[0005] The patent document with publication number CN 108254905 A discloses a lens for a 4K LCOS projection system with a 3LCOS telecentric optical system. The lens consists of nine spherical lenses, with a focal length of 34mm, F#2.8, a back working distance of 18.93mm, a telecentricity of less than 1°, a total lens length of 157.3mm, and a spatial cutoff frequency of 140lp / mm@MTF value greater than 0.35. The lens has a long focal length and is suitable for engineering projection. It is difficult to achieve the projection requirements of a small screen and is large in size. Summary of the invention

[0006] In view of this, the present invention aims at the deficiencies of the prior art and provides a small-format projection lens and a projector based on LCOS.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a small-format projection lens based on LCOS, comprising a front group and a rear group coaxially arranged in sequence from the projection screen side to the LCOS chip side along the direction of light, and an aperture is arranged between the front group and the rear group; the front group comprises a negative refractive aspheric lens, a first negative meniscus lens, a second negative meniscus lens, and a positive meniscus lens coaxially arranged in sequence; the rear group comprises a first cemented lens, a second cemented lens, a positive refractive aspheric lens and a biconvex lens coaxially arranged in sequence.

[0008] Furthermore, the negative-power aspheric lens, the first negative meniscus lens, and the second negative meniscus lens are all low-refractive-index and low-dispersion lenses; and the positive meniscus lens is a low-refractive-index and high-dispersion lens.

[0009] Furthermore, the first cemented lens is a combination of a plano-convex lens with high refractive index and high dispersion and a biconcave lens with high refractive index and high dispersion; the second cemented lens is a combination of a biconvex lens with low refractive index and low dispersion and a negative meniscus lens with high refractive index and high dispersion; the positive refractive power aspheric lens and the biconvex lens are both low refractive index and low dispersion lenses.

[0010] Furthermore, both surfaces of the negative-power aspheric lens and the positive-power aspheric lens are made of even-order aspheric surfaces.

[0011] Furthermore, the first negative meniscus lens, the second negative meniscus lens, the positive meniscus lens, the first cemented lens, the second cemented lens and the biconvex lens all adopt spherical surfaces.

[0012] Furthermore, the negative-power aspheric lens, the first negative meniscus lens, the second negative meniscus lens, the positive meniscus lens, the first cemented lens, the second cemented lens, the positive-power aspheric lens and the biconvex lens are all made of glass.

[0013] Furthermore, the negative-power aspheric lens is the lens with the largest outer diameter in the front group, and the outer diameter of the negative-power aspheric lens is not greater than 24.5 mm; the outer diameter of each lens in the rear group is smaller than the outer diameter of the negative-power aspheric lens.

[0014] Furthermore, the projection lens length is ≤64.55 mm; the projection lens length is defined as the distance from the vertex of the front surface of the negative-power aspheric lens to the vertex of the rear surface of the biconvex lens.

[0015] Furthermore, the effective focal length of the projection lens is 10.06 mm, and the lens aperture value is F2.5; the resolution of the projection lens under the projection image is: when the resolution is 118 lp / mm, the lens MTF value is greater than 50%.

[0016] The present invention also provides a projector, comprising a 0.37-inch LCOS chip and the small-format projection lens based on LCOS as described above, wherein the projector has a projection ratio of 1.2, an offset of 100%, a telecentric angle of less than 1°, and an optical back intercept greater than 33.33 mm.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The small-format projection lens based on LCOS of the present invention adopts a negative refractive aspheric lens, a first negative meniscus lens, a second negative meniscus lens, a positive meniscus lens, an aperture, a first cemented lens, a second cemented lens, a positive refractive aspheric lens and a biconvex lens, which are coaxially arranged in sequence from the projection screen side to the LCOS chip side along the light direction. Through this design, the projection distance is short, the resolution is high, and the resolution is high. At the same time, the size is miniaturized and the structure is compact, which reduces the cost of the projection lens and can well meet the market demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an optical system diagram of an embodiment of the present invention;

[0020] Figure 2 is a modulation transfer function diagram of an embodiment of the present invention;

[0021] Figure 3 is a through-focus MTF curve diagram of an embodiment of the present invention;

[0022] Figure 4 4 is a field curvature & distortion diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0024] Example 1

[0025] like Figure 1As shown, an embodiment of the present invention provides a small-format projection lens based on LCOS, comprising a front group 3 and a rear group 4 coaxially arranged in sequence from the projection screen side 1 to the LCOS chip 2 side along the light direction, and an aperture S1 is arranged between the front group 3 and the rear group 4; the front group 3 comprises a negative refractive power aspheric lens L1, a first negative meniscus lens L2, a second negative meniscus lens L3, and a positive meniscus lens L4 coaxially arranged in sequence; the rear group 4 comprises a first cemented lens L5, a second cemented lens L6, a positive refractive power aspheric lens L7 and a biconvex lens L8 coaxially arranged in sequence.

[0026] The negative-power aspheric lens L1, the first negative meniscus lens L2, and the second negative meniscus lens L3 are all low-refractive-index and low-dispersion lenses; the positive meniscus lens L4 is a low-refractive-index and high-dispersion lens.

[0027] The first cemented lens L5 is a combination of a plano-convex lens L5-1 with a high refractive index and high dispersion and a biconcave lens L5-2 with a high refractive index and high dispersion; the second cemented lens L6 is a combination of a biconvex lens L6-1 with a low refractive index and low dispersion and a negative meniscus lens L6-2 with a high refractive index and high dispersion; the positive refractive power aspheric lens L7 and the biconvex lens L8 are both low refractive index and low dispersion lenses.

[0028] Both surfaces of the negative-power aspheric lens L1 and the positive-power aspheric lens L7 are even-order aspheric surfaces.

[0029] The first negative meniscus lens L2, the second negative meniscus lens L3, the positive meniscus lens L4, the first cemented lens L5, the second cemented lens L6 and the biconvex lens L8 all adopt spherical surfaces.

[0030] The negative-power aspheric lens L1, the first negative meniscus lens L2, the second negative meniscus lens L3, the positive meniscus lens L4, the first cemented lens L5, the second cemented lens L6, the positive-power aspheric lens L7 and the biconvex lens L8 are all made of glass.

[0031] The negative-power aspheric lens L1 is the lens with the largest outer diameter in the front group 3, and the outer diameter of the negative-power aspheric lens L1 is no more than 24.5 mm; the outer diameters of each lens in the rear group 4 are smaller than the outer diameter of the negative-power aspheric lens L1.

[0032] The length of the small-format projection lens based on LCOS in the embodiment of the present invention is ≤64.55 mm; the projection lens length is defined as the distance from the front surface vertex of the negative-power aspheric lens L1 to the back surface vertex of the biconvex lens L8.

[0033] The effective focal length of the small-format projection lens based on LCOS in the embodiment of the present invention is 10.06 mm, and the lens aperture value is F2.5.

[0034] like Figure 2 As shown, the resolution of the small-format projection lens based on LCOS in the embodiment of the present invention under the projection screen is: when the resolution is 118lp / mm, the MTF value of the lens is greater than 50%.

[0035] The image size of the small-size projection lens based on LCOS in the embodiment of the present invention is between 15 inches and 25 inches.

[0036] Table 1 shows the basic parameter values ​​of the lens design included in the small-format projection lens based on LCOS in the embodiment of the present invention along the direction of light from the projection screen 1 side to the LCOS chip 2 side.

[0037] Table 1 Basic parameter values ​​of lens design

[0038]

[0039]

[0040] In this embodiment, the aspheric surface data of the negative-power aspheric lens L1 and the positive-power aspheric lens L7 are shown in Table 2.

[0041] Table 2 Aspheric surface data

[0042]

[0043] The aspheric formula is:

[0044]

[0045] Where c is the basic curvature at the vertex, k is the cone coefficient, and α i r 2i is the high-order term of the aspheric surface.

[0046] Figure 3 This is a through-focus MTF curve diagram of a small-format projection lens based on LCOS according to an embodiment of the present invention; Figure 4 This is a field curvature distortion diagram of a small-format projection lens based on LCOS according to an embodiment of the present invention. The field curvature distortion diagram shows that the absolute value of the optical distortion of the small-format projection lens based on LCOS according to an embodiment of the present invention is less than 0.2%.

[0047] The embodiment of the present invention is based on a small-format projection lens of LCOS, which solves the user's needs for short projection distance, high resolution, high resolution, miniaturization, low cost and more realistic small screen in special application scenarios.

[0048] Example 2

[0049] An embodiment of the present invention provides a projector, including a 0.37-inch LCOS chip and an LCOS-based small-format projection lens of embodiment 1. The projector has a projection ratio of 1.2, an offset of 100%, a telecentric angle of less than 1°, and an optical back intercept greater than 33.33 mm.

[0050] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art can still modify or make equivalent substitutions to the specific implementations of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A small-format projection lens based on LCOS, characterized in that: It comprises a front group and a rear group which are coaxially arranged in sequence from the projection screen side to the LCOS chip side along the direction of light, and an aperture is arranged between the front group and the rear group; the front group comprises a negative refractive power aspheric lens, a first negative meniscus lens, a second negative meniscus lens, and a positive meniscus lens which are coaxially arranged in sequence; the rear group comprises a first cemented lens, a second cemented lens, a positive refractive power aspheric lens, and a biconvex lens which are coaxially arranged in sequence.

2. The small-format projection lens based on LCOS according to claim 1, characterized in that: The negative-power aspheric lens, the first negative meniscus lens, and the second negative meniscus lens are all low-refractive-index and low-dispersion lenses; the positive meniscus lens is a low-refractive-index and high-dispersion lens.

3. The small-format projection lens based on LCOS according to claim 1, characterized in that: The first cemented lens is a combination of a plano-convex lens with high refractive index and high dispersion and a biconcave lens with high refractive index and high dispersion; the second cemented lens is a combination of a biconvex lens with low refractive index and low dispersion and a negative meniscus lens with high refractive index and high dispersion; the positive refractive power aspheric lens and the biconvex lens are both low refractive index and low dispersion lenses.

4. The small-format projection lens based on LCOS according to claim 1, characterized in that: Both the negative-power aspheric lens and the positive-power aspheric lens have even-order aspheric surfaces on their surfaces.

5. The small-format projection lens based on LCOS according to claim 1, characterized in that: The first negative meniscus lens, the second negative meniscus lens, the positive meniscus lens, the first cemented lens, the second cemented lens and the biconvex lens all adopt spherical surfaces.

6. The small-format projection lens based on LCOS according to claim 1, characterized in that: The negative-power aspheric lens, the first negative meniscus lens, the second negative meniscus lens, the positive meniscus lens, the first cemented lens, the second cemented lens, the positive-power aspheric lens and the biconvex lens are all made of glass.

7. The small-format projection lens based on LCOS according to claim 1, characterized in that: The negative-power aspheric lens is the lens with the largest outer diameter in the front group, and the outer diameter of the negative-power aspheric lens is no more than 24.5 mm; the outer diameters of each lens in the rear group are smaller than the outer diameter of the negative-power aspheric lens.

8. The small-format projection lens based on LCOS according to claim 1, characterized in that: The projection lens length is ≤64.55 mm; the projection lens length is defined as the distance from the vertex of the front surface of the negative-power aspheric lens to the vertex of the back surface of the biconvex lens.

9. The small-format projection lens based on LCOS according to claim 1, characterized in that: The effective focal length of the projection lens is 10.06mm, and the lens aperture value is F2.5; The resolution of the projection lens under the projection image is: when the resolution is 118lp / mm, the lens MTF value is greater than 50%.

10. A projector, characterized in that: It comprises a 0.37-inch LCOS chip and a small-format projection lens based on LCOS according to any one of claims 1 to 9, wherein the projector has a projection ratio of 1.2, a bias of 100%, a telecentric angle of less than 1°, and an optical back intercept greater than 33.33 mm.

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