Small-format projection lens and projector based on lcos

Abstract

The application provides a small frame size projection lens based on LCOS and a projector, and belongs to the technical field of optical lenses. The small frame size projection lens 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 light direction, 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 cementus lens, a positive refractive power aspheric lens and a lenticular lens which are coaxially arranged in sequence. The application has the advantages of short projection distance, high resolving power and high resolution, small size, compact structure, reduced cost of the projection lens and good market demand.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lens, in particular to a small-format size projection lens based on LCOS and a projector. BACKGROUND

[0002] The application of projection technology in daily work and life is very wide, with the development of emerging technologies, the pursuit of high resolution, high resolution and high realistic picture of the user for the projection picture is constantly emerging. At the same time, the emerging technology matures in development, the existing projection lens cannot meet the user's demand for some special scenes, therefore, a small-format size projection lens based on LCOS is developed and applied.

[0003] LCOS is the 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 LCOS chip pixels, the projected picture will be more realistic.

[0004] In the patent literature with publication number CN 103176262 A, a high-definition LCOS lens suitable for 1920x1080 single-chip LCOS global surface is disclosed. The lens is composed of eight spherical lenses, with focal length 19.24mm, F#1.7, projection ratio 1.8, spatial cutoff frequency 60lp / mm@MIF value greater than 0.5. But the projection ratio value of the lens is large, and a long projection distance is needed to realize the projection of small picture, which is not suitable for the trend of product miniaturization.

[0005] In the patent literature with publication number CN 108254905 A, a lens for 3LCOS telecentric optical system of 4K LCOS projection system is disclosed. The lens is composed of nine spherical lenses, with focal length 34mm, F#2.8, back working distance 18.93mm, telecentricity less than 1°, total length of lens 157.3mm, spatial cutoff frequency 140lp / mm@MTF value greater than 0.35. The lens has long focal length, which is suitable for engineering projection, and it is difficult to realize the projection of small picture, and the volume is large. SUMMARY

[0006] Therefore, the present application provides a small-format size projection lens based on LCOS and a projector to solve the problems in the prior art.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is: a small frame size 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 light direction, and a diaphragm 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 coaxially arranged in sequence; and the rear group comprises a first cemented lens, a second cemented lens, a positive refractive power aspheric lens and a lenticular lens coaxially arranged in sequence.

[0008] Further, the negative refractive 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] Further, the first cemented lens is composed of a high refractive index and high dispersion plano-convex lens and a high refractive index and high dispersion double-concave lens; the second cemented lens is composed of a low refractive index and low dispersion lenticular lens and a high refractive index and high dispersion negative meniscus lens; and the positive refractive power aspheric lens and the lenticular lens are both low refractive index and low dispersion lenses.

[0010] Further, both surfaces of the negative refractive power aspheric lens and the positive refractive power aspheric lens adopt even aspheric surfaces.

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

[0012] Further, the negative refractive 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 refractive power aspheric lens and the lenticular lens are all made of glass.

[0013] Further, the negative refractive power aspheric lens is the lens with the largest outer diameter in the front group, and the outer diameter of the negative refractive power aspheric lens is not greater than 24.5 mm; and the outer diameters of the lenses in the rear group are all smaller than the outer diameter of the negative refractive power aspheric lens.

[0014] Further, the length of the projection lens is ≤64.55 mm; and the length of the projection lens is defined as the distance from the front surface vertex of the negative refractive power aspheric lens to the rear surface vertex of the lenticular lens.

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

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

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

[0018] The small-format-size projection lens based on LCOS of the application adopts the negative-power aspheric lens, the first negative meniscus lens, the second negative meniscus lens, the positive meniscus lens, the diaphragm, the first cemented lens, the second cemented lens, the positive-power aspheric lens and the lenticular lens arranged coaxially in sequence from the projection screen side to the LCOS chip side along the light direction, so that the projection distance is short, the resolution is high, the size is small, the structure is compact, the cost of the projection lens is reduced, and the market demand can be well met. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The optical system diagram of the embodiment of the application;

[0020] Figure 2 The modulation transfer function diagram of the embodiment of the application;

[0021] Figure 3 The defocus MTF curve diagram of the embodiment of the application;

[0022] Figure 4 The field curvature & distortion diagram of the embodiment of the application. DETAILED DESCRIPTION

[0023] To make the purpose, technical scheme and advantages of the embodiment of the application clearer, the technical scheme of the embodiment of the application will be described clearly and completely in combination with the drawings of the embodiment of the application. Obviously, the described embodiment is a part of the embodiments of the application, not all the embodiments. Based on the described embodiments of the application, all other embodiments obtained by those skilled in the art belong to the protection scope of the application.

[0024] Embodiment 1

[0025] As Figure 1As shown, the embodiment of the present application provides a small frame size projection lens based on LCOS, which comprises a front group 3 and a rear group 4 arranged coaxially in sequence from the projection screen side 1 to the LCOS chip 2 side along the light direction, and a diaphragm S1 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 arranged coaxially in sequence; and the rear group 4 comprises a first cemented lens L5, a second cemented lens L6, a positive refractive power aspheric lens L7, and a lenticular lens L8 arranged coaxially in sequence.

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

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

[0028] Both surfaces of the negative refractive power aspheric lens L1 and the positive refractive power aspheric lens L7 adopt even 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 lenticular lens L8 all adopt spherical surfaces.

[0030] The negative refractive 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 refractive power aspheric lens L7, and the lenticular lens L8 are all made of glass.

[0031] The negative refractive power aspheric lens L1 is the lens with the largest outer diameter in the front group 3, and the outer diameter of the negative refractive power aspheric lens L1 is not greater than 24.5 mm; and the outer diameters of the lenses in the rear group 4 are all smaller than the outer diameter of the negative refractive power aspheric lens L1.

[0032] The small frame size projection lens based on LCOS in the embodiment of the present application has a length of ≤64.55 mm; and the projection lens length is defined as the distance from the front surface vertex of the negative refractive power aspheric lens L1 to the rear surface vertex of the lenticular lens L8.

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

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

[0035] The format size of the small-format size projection lens based on LCOS in the embodiment of the present application is 15 inches to 25 inches.

[0036] The lens design basic parameter values of the small-format size projection lens based on LCOS in the embodiment of the present application along the light direction from the projection screen 1 side to the LCOS chip 2 side are shown in Table 1.

[0037] Table 1 Lens design basic parameter values

[0038]

[0039]

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

[0041] Table 2 Aspheric surface data

[0042]

[0043] The aspheric formula is:

[0044]

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

[0046] Figure 3 is the defocus MTF curve of the small-format size projection lens based on LCOS in the embodiment of the present application; Figure 4 is the field curvature distortion graph of the small-format size projection lens based on LCOS in the embodiment of the present application. The field curvature distortion graph shows that the absolute value of the optical distortion of the small-format size projection lens based on LCOS in the embodiment of the present application is less than 0.2%.

[0047] The small-format size projection lens based on LCOS in the embodiment of the present application solves the needs of users for short projection distance, high resolution, high resolution, miniaturization, low cost and more realistic small pictures in special application scenarios.

[0048] Embodiment 2

[0049] The embodiment of the present application provides a projector, which comprises a 0.37-inch LCOS chip and the small-frame-size projection lens based on the LCOS in the embodiment 1, the projection ratio of the projector is 1.2, the offset is 100%, the telecentric angle is less than 1°, and the optical back intercept is greater than 33.33mm.

[0050] The above embodiments are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application is described in detail with reference to the above embodiments, the ordinary skilled in the art can still modify or equivalently replace the specific embodiments of the present application without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application is within the protection scope of the claims of the application to be approved.

Claims

1. A small-format size projection lens based on LCOS, characterized in that: The front group and the rear group are sequentially arranged coaxially from the projection screen side to the LCOS chip side along the light direction, and an aperture is arranged between the front group and the rear group; the front group is composed of a negative refractive power aspheric lens, a first negative meniscus lens, a second negative meniscus lens and a positive meniscus lens arranged coaxially; the rear group is composed of a first cemented lens, a second cemented lens, a positive refractive power aspheric lens and a lenticular lens arranged coaxially; The negative refractive power aspheric lens is concave on the optical axis on both the projection screen side and the LCOS chip side; the first negative meniscus lens, the second negative meniscus lens and the positive meniscus lens are all convex towards the projection screen side; the first cemented lens is composed of a biconcave lens and a biconvex lens; the second cemented lens is composed of a lenticular lens and a negative meniscus lens; the positive refractive power aspheric lens is a meniscus lens with a convex surface towards the LCOS chip side; The curvature radii of the negative refractive 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 refractive power aspheric lens and the lenticular lens close to the projection screen side are-144.72 mm, 54.667 mm, 33.073 mm, 25.077 mm, -592.912 mm, 28.33 mm, -221.929 mm and 43.742 mm respectively, and the curvature radii close to the LCOS chip side are 62.039 mm, 12.422 mm, 13.405 mm, 274.299 mm, 45.581 mm, -45.989 mm, -15.607 mm and -27.525 mm respectively.

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

3. The small-throw projection lens based on LCOS according to claim 1, characterized in that: The first cemented lens is composed of a high-refractive and high-dispersive biconvex lens and a high-refractive and high-dispersive biconcave lens; the second cemented lens is composed of a low-refractive and low-dispersive lenticular lens and a high-refractive and high-dispersive negative meniscus lens; the positive refractive power aspheric lens and the lenticular lens are both low-refractive and low-dispersive lenses.

4. The small-throw projection lens based on LCOS according to claim 1, characterized in that: Both surfaces of the negative refractive power aspheric lens and the positive refractive power aspheric lens adopt even aspheric surfaces.

5. The small-throw LCOS-based projection lens of claim 1, wherein: The first negative meniscus lens, the second negative meniscus lens, the positive meniscus lens, the first cemented lens, the second cemented lens and the lenticular lens all adopt spherical surfaces.

6. The small-throw LCOS-based projection lens of claim 1, wherein: The negative refractive 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 refractive power aspheric lens and the lenticular lens are all made of glass.

7. The small-throw LCOS-based projection lens of claim 1, wherein: 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 less than the outer diameter of the negative-power aspheric lens.

8. The small-throw LCOS-based projection lens of claim 1, wherein: The projection lens length is less than or equal to 64.55 mm; the projection lens length is defined as the distance from the front surface vertex of the negative-power aspheric lens to the rear surface vertex of the lenticular lens.

9. The small-throw LCOS-based projection lens of claim 1, wherein: 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 projected image is that the lens MTF value is greater than 50% when the resolution is 118 lp / mm.

10. A projector characterized by comprising: The projector comprises a 0.37-inch LCOS chip and a small-format size LCOS-based projection lens according to any one of claims 1-9, the projection ratio of the projector is 1.2, the offset is 100%, the telecentric angle is less than 1°, and the optical back intercept is greater than 33.33 mm.

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