CN112433342B

CN112433342B - Ultra-high resolution miniature projection lens

Info

Publication number: CN112433342B
Application number: CN202011395413.6A
Authority: CN
Inventors: 何磊
Original assignee: Sichuan Changhong Electric Co Ltd
Current assignee: Sichuan Changhong Electric Co Ltd
Priority date: 2020-12-03
Filing date: 2020-12-03
Publication date: 2022-05-03
Anticipated expiration: 2040-12-03
Also published as: CN112433342A

Abstract

The invention discloses an ultra-high resolution miniature projection lens which comprises a first lens group with a positive focal length, a diaphragm, a second lens group with a positive focal length, a galvanometer, a prism, a window sheet and a DMD (digital micromirror device) which are sequentially arranged. The first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are arranged in sequence; the second lens group comprises a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are arranged in sequence, and the sixth lens, the seventh lens and the eighth lens are cemented lenses. The second lens is a plastic aspheric lens, the tenth lens is a glass aspheric lens, and other lenses are glass spherical lenses. The first lens, the second lens, the third lens and the third cemented lens have negative focal power, and the fourth lens, the fifth lens, the ninth lens and the tenth lens have positive focal power. The miniature projection lens has small total length, can be compatible with XPR technology, realizes 4K ultrahigh resolution and meets the requirements of miniature projection equipment.

Description

Ultra-high resolution miniature projection lens

Technical Field

The invention relates to the technical field of WeChat projection lenses, in particular to an ultrahigh-resolution miniature projection lens.

Background

The projection lens is a core component of the projection device: after passing through the reflective or transmissive light modulation device, the light needs to be projected onto a projection screen through a projection lens for imaging.

As the projection device plays a larger and larger role in life, the application field is also increased. More devices need to be embedded into a miniature projection device, which has higher and higher requirements on a projection lens, and the miniature projection device has smaller size and more compact structure.

However, in order to achieve a small size, the resolution of the projection lens currently available on the market is reduced, and thus the requirement of high resolution users cannot be met.

Disclosure of Invention

The invention provides an ultra-high resolution miniature projection lens, which aims to solve the problem that the existing miniature projection lens cannot meet the high resolution required by the market.

The technical scheme adopted by the invention is as follows: the utility model provides a miniature projection lens of ultrahigh resolution, including first lens group, diaphragm, the second lens group, prism, window piece and the DMD that set gradually with the positive focal length.

Preferably, the lens barrel further includes a galvanometer disposed between the second lens group and the prism.

Preferably, the first lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens, which are arranged in this order; the second lens group comprises a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are arranged in sequence, and the sixth lens, the seventh lens and the eighth lens are cemented lenses.

Preferably, the second lens is a plastic aspheric lens, the tenth lens is a glass aspheric lens, and the other lenses are glass spherical lenses.

Preferably, the first lens, the second lens, the third lens and the third cemented lens have negative focal power, and the fourth lens, the fifth lens, the ninth lens and the tenth lens have positive focal power.

Preferably, the optical constants of the materials used for all the spherical lenses satisfy the following conditional expressions: 1.48< Nd < 1.95, and 17< Vd <85, wherein Nd and Vd are respectively the refractive index and Abbe number of the used optical material to d light.

Preferably, the lens is a telecentric lens, and the projection ratio of the lens is 1.2.

Preferably, the effective focal length of the lens is 12.74mm, and the effective focal length of the lens is 1.7F/no.

Preferably, the first lens is made of optical glass with a refractive index of 1.95.

Preferably, the lens is a 0.47 inch DMD chip.

The invention has the beneficial effects that:

(1) the micro projection lens disclosed by the invention has a small total length and meets the requirements of micro projection equipment.

(2) The miniature projection lens disclosed by the invention adopts a telecentric system, the illumination is uniform, and the illumination of the full field is not less than 0.8.

(3) The micro projection lens disclosed by the invention can be compatible with an XPR technology, and can realize 4K resolution when the XPR is used; when XPR is not used, 1080P resolution is achieved.

(4) The miniature projection lens disclosed by the invention has the advantages that the contrast full-field of view is higher than 0.8, the imaging quality is good, and the distortion can reach within 1%.

(5) Compared with other micro-projection lenses on the market, the last lens of the lens adopts a glass aspheric surface, so that the problem of serious focus leakage caused by heating of the plastic aspheric surface of the other micro-projection lenses can be effectively solved.

(6) The first lens is made of optical glass material with high refractive index, so that the height of a light beam can be effectively reduced, and the first lens has great effects on correcting distortion and reducing the caliber of a subsequent lens.

(7) The plastic aspheric surface is arranged at the position of the second lens, so that the influence on the aspheric surface shape caused by scratch and collision can be effectively avoided.

(8) The triple cemented lens has a great effect on correcting the secondary spectrum, and the cemented lens is arranged near the diaphragm, so that the chromatic aberration correction effect is good.

Drawings

Fig. 1 is an optical structure diagram of an ultra-high resolution micro projection lens provided in embodiment 1 of the present invention.

Fig. 2 is a MTF graph of each field of view transfer function of the ultra-high resolution micro projection lens according to embodiment 1 of the present invention.

Fig. 3 is a dot-sequence diagram of an ultra-high resolution micro projection lens provided in embodiment 1 of the present invention.

Fig. 4 is a field curvature distortion diagram of an ultra-high resolution micro projection lens provided in embodiment 1 of the present invention.

Fig. 5 is a relative illuminance diagram of an ultra-high resolution micro projection lens according to embodiment 1 of the present invention.

Fig. 6 is a vertical axis chromatic aberration diagram of an ultra-high resolution micro projection lens provided in embodiment 1 of the present invention.

Fig. 7 is an optical structure diagram of an ultra-high resolution micro projection lens according to embodiment 2 of the present invention.

Fig. 8 is a MTF graph of each field of view transfer function of the ultra-high resolution micro projection lens according to embodiment 2 of the present invention.

Fig. 9 is a dot-sequence diagram of an ultra-high resolution micro projection lens according to embodiment 2 of the present invention.

Fig. 10 is a field curvature distortion diagram of an ultra-high resolution micro projection lens according to embodiment 2 of the present invention.

Fig. 11 is a vertical axis chromatic aberration diagram of an ultra-high resolution micro projection lens provided in embodiment 2 of the present invention.

Reference numerals: 1. a first lens; 2. a second lens; 3. a third lens; 4. a fourth lens; 5. a fifth lens; 6. a diaphragm; 7. a sixth lens; 8. a seventh lens; 9. an eighth lens; 10. a ninth lens; 11. a tenth lens; 12. a galvanometer; 13. a prism; 14. a window sheet.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below with reference to the accompanying drawings, but embodiments of the present invention are not limited thereto.

It should be understood that the various steps recited in the method embodiments of the present disclosure may be performed in a different order, and/or performed in parallel. Moreover, method embodiments may include additional steps and/or omit performing the illustrated steps. The scope of the present disclosure is not limited in this respect.

Example 1:

referring to fig. 1, fig. 1 is an optical structure diagram of a micro projection lens provided in an application example of the present invention; the invention provides a miniature projection lens of ultra-high resolution, this lens includes: the lens comprises a first lens group with a positive focal length, a diaphragm 6, a second lens group with a positive focal length, a galvanometer 12, a prism 13, a window sheet 14 and a DMD which are arranged in sequence; the first lens group comprises a first lens 1 which is a glass spherical lens, a second lens 2 which is a plastic aspheric lens, a third lens 3 which is a glass spherical lens, a fourth lens 4 which is a glass spherical lens and a fifth lens 5 which is a glass spherical lens; the second lens group includes a sixth lens 7 which is a glass spherical lens, a seventh lens 8 which is a glass spherical lens, an eighth lens 9 which is a glass spherical lens, a ninth lens 10 which is a glass spherical lens, and a tenth lens 11 which is a glass aspherical lens.

The first lens 1 has negative focal power, the second lens 2 has negative focal power, the third lens 3 has negative focal power, the fourth lens 4 has positive focal power, the fifth lens 5 has positive focal power, the sixth lens 7, the seventh lens 8 and the eighth lens 9 form a triple cemented lens which has negative focal power, the ninth lens 10 has positive focal power, and the tenth lens 11 has positive focal power.

The first lens 1 is made of high-refractive-index optical glass, the refractive index of the existing optical glass is generally 1.4-2.0, the refractive index of the material used for the first lens 1 is high, about 1.95 is selected, the height of a light beam can be effectively reduced, and the optical lens has great effects on correcting distortion and reducing the calibers of subsequent lenses. The plastic aspheric surface is arranged at the position of the second lens, so that the influence of scratch and collision on the surface shape of the aspheric surface can be effectively avoided. The triple cemented lens has a great effect on correcting the secondary spectrum, and the cemented lens is arranged near the diaphragm 6, so that the chromatic aberration correction effect is good. The tenth lens 11 can effectively solve the defect of lens focusing caused by heating of a plastic aspheric surface. The lens has the characteristics of large bias, large projection ratio and high imaging quality.

The specific parameters of the micro projection lens provided by the invention are shown in table 1:

TABLE 1

N in Table 1_dRepresents the refractive index, V_dRepresents the Abbe number.

Wherein the second lens 2 and the tenth lens 11 are aspherical surfaces, and the expression of the aspherical surface type is

Where Z denotes a distance in the optical axis direction from a point on the aspherical surface to the vertex of the aspherical surface, ρ denotes a distance from the point on the aspherical surface to the optical axis, c denotes a central curvature of the aspherical surface, k denotes a conicity, and An denotes the number of higher orders of the aspherical surface.

The aspheric coefficients of the second lens 2 and the tenth lens 11 are shown in table 2.

TABLE 2

In this embodiment, a DMD chip of 0.47 inch is used, the pixel size is 5.4 μ, the corresponding design resolution is 93lp/mm, the effective focal length is 12.74mm, the F/No. is 1.7, the offset is 100%, the projection distance is 1.6m to 3.2m, the corresponding projection size is 60 inches to 120 inches, the projection ratio is 1.2, and the 4K resolution can be achieved by using a galvanometer. The application example is a telecentric system and has small telecentricity.

From the lens parameters in table 1, the micro projection lens shown in fig. 1 can be obtained. FIG. 2 is an image of MTF variation of a full field with spatial frequency, the closer the MTF is to a diffraction limit, the better the imaging quality is, and the better the imaging quality is when the MTF of each field under the spatial frequency of 93lp/mm is greater than 0.5. FIG. 3 is a dot diagram of each field, and the lens full field RMS is smaller than the pixel size (5.4 μ), so that clear imaging can be realized. In FIG. 4, the left image is an image of field curvature as a function of field of view, the field curvature being in the range of-0.05 mm to 0.05 mm; the right image is an image with distortion varying with the field of view, and the distortion is controlled within 1%. Fig. 5 is an image showing the variation of relative illuminance with the field of view, where the relative illuminance refers to the ratio of the illuminance at one field of view to the central illuminance, and it can be seen that the illuminance is not less than 0.8 in the full field of view. FIG. 6 is a vertical axis chromatic aberration image, the vertical axis chromatic aberration obtained from the image is controlled below 2.1 μ, which is smaller than half pixel size, and the vertical axis chromatic aberration is well controlled.

Example 2

Referring to fig. 7, fig. 7 is an optical structure diagram of an ultra-high resolution micro projection lens provided in embodiment 2 of the present invention. In this embodiment, a conventional resolution of 1080P is achieved by adjusting the back intercept without using a galvanometer (XPR), and specific parameters are shown in table 3:

TABLE 3

From the lens parameters described in table 3, a micro projection lens as shown in fig. 7 can be obtained. FIG. 8 is an image of full field MTF as a function of spatial frequency, with a transfer function MTF >0.45 for each field at 93lp/mm spatial frequency. Fig. 9 is a dot diagram of each field of view whose spot size is larger due to the presence of spherical aberration, but whose full field RMS is still smaller than the pixel size (5.4 μ). In FIG. 10, the left image is an image of field curvature as a function of field of view, the field curvature being in the range of-0.05 mm to 0.05 mm; the right image is an image with distortion varying with the field of view, and the distortion is controlled within 1%. FIG. 11 is a vertical axis chromatic aberration image, the vertical axis chromatic aberration obtained from the image is controlled below 2.1 μ, which is smaller than half pixel size, and the vertical axis chromatic aberration is well controlled.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A miniature projection lens of ultra-high resolution, wherein include the first lens battery with positive focal length, diaphragm, second lens battery with positive focal length, galvanometer, prism, window slice and DMD set up sequentially;

the first lens group consists of a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are arranged in sequence; the second lens group consists of a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are arranged in sequence, and the sixth lens, the seventh lens and the eighth lens are triple cemented lenses;

the second lens is a plastic aspheric lens, the tenth lens is a glass aspheric lens, and other lenses are glass spherical lenses;

the first lens, the second lens, the third lens and the third cemented lens are negative focal powers, and the fourth lens, the fifth lens, the ninth lens and the tenth lens are positive focal powers;

the optical constants of the materials used for all the spherical lenses satisfy the following conditional expressions: 1.48< Nd < 1.95, and 17< Vd <85, wherein Nd and Vd are respectively the refractive index and Abbe number of the used optical material to d light;

the effective focal length of the lens is 12.74mm, and the F/NO. is 1.7.

2. The ultra-high resolution micro projection lens of claim 1, wherein the lens is telecentric and the lens has a throw ratio of 1.2.

3. The ultra-high resolution micro projection lens of claim 1, wherein the first lens is made of optical glass with a refractive index of 1.95.

4. The ultra-high resolution micro projection lens of claim 1, wherein the lens is a 0.47 inch DMD chip.