CN108303784A - A kind of ultrashort out-of-focus projection's optical system - Google Patents

Abstract

The invention discloses a kind of ultrashort out-of-focus projection's optical systems, are disposed on projecting direction：Dmd chip, equivalent prism, refractor component and non-spherical reflector；The refractor component includes the first lens, the second lens, the third lens, the 4th lens and the 5th lens set gradually along projecting direction；Diaphragm, the 6th lens, the 7th lens, the 8th lens, the 9th lens, the tenth lens, the 11st lens and the 12nd lens.High resolution of the invention, projection are not run coke for convex surface even aspheric surface, high temperature than being less than 0.2, speculum, be can be mass.

Description

An ultra-short focal projection optical system

【Technical field】

The invention relates to an optical system in projection technology, in particular to an ultra-short-focus projection optical system.

【Background technique】

In recent years, with the development of projection technology, ultra-short-throw projection lenses have been widely used in laser TVs and high-brightness projectors. Currently, ultra-short-throw projection lenses on the market have the following disadvantages:

1. The refraction ultra-short-focus lens is used, and the throw ratio is above 0.45, which cannot meet the needs of users to project a large screen of more than 100 inches on a TV cabinet with a width of 50 cm at home. In addition, in order to control distortion, it is extremely difficult to manufacture.

2. The catadioptric hybrid ultra-short-focus lens is adopted, and the reflector is a free-form surface, which is difficult to manufacture.

3. The catadioptric hybrid ultra-short-focus lens is used. The mirror is a concave free-form surface. The peripheral image quality has extremely high requirements on the surface shape of the free-form surface, and it is difficult to correct it. Therefore, the peripheral image quality is usually not good, and the production yield cannot be guaranteed.

4. The ultra-short-focus lenses on the market all use plastic aspheric surfaces, which are sensitive to high temperatures and tend to lose focus when the projector is working.

Therefore, the present invention just produces based on above deficiency.

【Content of invention】

The technical problem to be solved by the present invention is to provide an ultra-short-focus projection optical system with high resolution, a throw ratio of less than 0.2, a convex even-order aspheric mirror, no out-of-focus at high temperature, and mass production.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions: an ultra-short-focus projection optical system, which is characterized in that, in the projection direction, there are successively arranged: a DMD chip, an equivalent prism, a refracting lens assembly and an aspheric reflector mirror;

The refracting lens assembly includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence along the projection direction; a diaphragm, a sixth lens, a seventh lens, an eighth lens, and a ninth lens , the tenth lens, the eleventh lens and the twelfth lens.

An ultra-short-focus projection optical system as described above is characterized in that the refractive power of the first lens is positive, the refractive power of the second lens is negative, and the refractive power of the third lens is is positive, the refractive power of the fourth lens is negative, the refractive power of the fifth lens is positive, the refractive power of the sixth lens is negative, and the refractive power of the seventh lens is positive , the power of the eighth lens is negative, the power of the ninth lens is negative, the power of the tenth lens is positive, and the power of the eleventh lens is positive, The refractive power of the twelfth lens is negative.

An ultra-short-focus projection optical system as described above is characterized in that the Abbe number vd ₂ of the second lens and the Abbe number vd ₃ of the third lens satisfy: 57≤vd ₃ -vd ₂ ≤60; the third The Abbe number vd ₃ of the lens and the Abbe number vd ₄ of the fourth lens satisfy: 54≤vd ₃ -vd ₄ ≤57; the aspheric mirror is a convex even-order aspheric surface, and the focal power satisfies: -0.035 ≤φ ₁₃₀ ≤-0.03.

An ultra-short-focus projection optical system as described above is characterized in that the two sides of the twelfth lens are bent toward the DMD chip, and the focal power satisfies: _{-0.013≤φ12≤} -0.012, the twelfth lens and the DMD The distance between the chips is L, and the distance between the DMD chip and the center of the aspheric mirror is LA, satisfying: L/LA>1.5.

The above-mentioned ultra-short-focus projection optical system is characterized in that the second lens and the third lens are bonded by optical glue, and the third lens and the fourth lens are bonded by optical glue.

The above-mentioned ultra-short-focus projection optical system is characterized in that the first lens is a glass aspheric surface, the twelfth lens is a plastic aspheric surface, and the aspheric mirror is a plastic aspheric surface.

A kind of ultra-short-focus projection optical system as described above, it is characterized in that, the surface shape of the aspheric surface of described first lens, twelfth lens and aspheric reflector satisfies the following equation:

The parameter c in the above equation is the curvature corresponding to the radius, y is the radial coordinate and its unit is the same as the lens length unit, and k is the conic conic conic coefficient; when the k coefficient is less than -1, the surface curve of the lens is a hyperbola; When the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is Circular, when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the even-order aspheric coefficients corresponding to each radial coordinate.

Compared with the prior art, an ultra-short-focus projection optical system of the present invention achieves the following effects:

1. The present invention realizes a throw ratio below 0.2, adopts a plastic aspheric surface and does not run out of focus at high temperature.

2. The present invention uses convex even-order aspheric mirrors, avoids free-form surfaces, is easy to process, and has lower surface sensitivity than concave aspheric mirrors, and is suitable for mass production.

【Description of drawings】

The specific embodiment of the present invention is described in further detail below in conjunction with accompanying drawing, wherein:

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is the optical path schematic diagram of the present invention;

Description of drawings: 100, DMD chip; 110, equivalent prism; 120, refracting lens assembly; 130, aspheric mirror; 1, first lens; 2, second lens; 3, third lens; 4, fourth Lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Eleventh lens; 12. Twelfth lens 13. Aperture.

【Detailed ways】

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, an ultra-short-focus projection optical system is provided with: a DMD chip 100, an equivalent prism 110, a refractive lens assembly 120, and an aspheric mirror 130 in the projection direction;

The refracting lens assembly 120 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 5 arranged in sequence along the projection direction; an aperture 13, a sixth lens 6, and a seventh lens 7. The eighth lens 8 , the ninth lens 9 , the tenth lens 10 , the eleventh lens 11 and the twelfth lens 12 .

As shown in Figure 1 and Figure 2, in this embodiment, the optical power of the first lens 1 is positive, the optical power of the second lens 2 is negative, and the optical power of the third lens 3 is power is positive, the power of the fourth lens 4 is negative, the power of the fifth lens 5 is positive, the power of the sixth lens 6 is negative, and the power of the seventh lens 7 is negative. The optical power of the eighth lens 8 is negative, the optical power of the ninth lens 9 is negative, the optical power of the tenth lens 10 is positive, and the optical power of the eleventh lens 10 is positive. The refractive power of the lens 11 is positive, and the refractive power of the twelfth lens 12 is negative.

In this embodiment, the image beam is emitted from the DMD chip 100, passes through the equivalent prism 110, and then enters the refraction lens assembly 120 at an angle close to parallel light, and performs the first imaging between the refraction lens assembly 120 and the aspheric mirror 130 , the aspheric mirror 130 reflects the first image to the projection screen to form a high-quality image.

As shown in Figures 1 and 2, in this embodiment, the first lens 1 adopts a glass aspheric surface to correct the astigmatism of a large field of view, and the second lens 2, the third lens 3 and the fourth lens 4 form a triplet lens , correct the axial chromatic aberration and off-axis chromatic aberration of the system to ensure the reproducibility of the color; the eighth lens 8 and the ninth lens 9 adopt a nearly symmetrical shape to increase the size of the off-axis field of view, so that the lens has a larger The projection ratio; the twelfth lens 12 uses an aspheric surface to correct the aberration of the enlarged off-axis field of view, and correct the advanced distortion and advanced astigmatism caused by the enlargement of the field of view. By placing a convex mirror on the refraction path, Further corrections are made for distortion and astigmatism, resulting in a high-quality image at the screen.

As shown in Figure 1 and Figure 2, in this embodiment, the Abbe number vd _{2 of the second lens 2} and the Abbe number vd 3 of the third lens ₃ satisfy: 57≤vd ₃ -vd ₂ ≤60; the third The Abbe number vd 3 of the lens ₃ and the Abbe number vd 4 of the fourth lens ₄ satisfy: 54≤vd ₃ -vd ₄ ≤57; the aspheric mirror 130 is a convex even-order aspheric surface, and the focal power satisfies : -0.035≤φ ₁₃₀ ≤-0.03, which can reduce the optical path difference between the peripheral field of view and the central field of view, so that the image quality of the peripheral field of view of the mirror has a low sensitivity to the surface type, and the sensitivity of the assembly tolerance of the system can be greatly reduced. Carry out mass production.

As shown in Figures 1 and 2, in this embodiment, the two sides of the twelfth lens 12 are bent towards the DMD chip 100, and the optical power satisfies: -0.013≤φ12≤- _0.012 , the twelfth lens 12 and The distance between the DMD chip 100 is L, and the distance between the DMD chip 100 and the center of the aspheric mirror 130 is LA, which satisfies: L/LA>1.5, which can prevent the projector from running out of focus under high temperature conditions.

As shown in Figures 1 and 2, in this embodiment, the second lens 2 and the third lens 3 are bonded by optical glue, and the third lens 3 and the fourth lens 4 are bonded by optical glue .

As shown in FIGS. 1 and 2 , in this embodiment, the first lens 1 is a glass aspheric surface, the twelfth lens 12 is a plastic aspheric surface, and the aspheric mirror 130 is a plastic aspheric surface.

As shown in Figures 1 and 2, in this embodiment, the aspherical surface shapes of the first lens 1, the twelfth lens 12 and the aspheric mirror 130 satisfy the following equation:

The parameter c in the above equation is the curvature corresponding to the radius, y is the radial coordinate and its unit is the same as the lens length unit, and k is the conic conic conic coefficient; when the k coefficient is less than -1, the surface curve of the lens is a hyperbola; When the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is Circular, when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the even-order aspheric coefficients corresponding to each radial coordinate.

The following case is the actual design parameters of the ultra-short-focus lens with a throw ratio of 0.2 P:

The coefficient of the aspheric mirror S1 is:

k: -17.01562

a1:0

a2: 9.4949766e-008

a3: -3.1015008e-011

a4: 2.4742502e-014

a5: -4.511753e-018

a6: 1.1123599e-022

a7:9.4602141e-026;

The coefficient of the first surface S23 of the twelfth lens 12 is:

k: 223.459

a1:0

a2: 1.7833543e-006

a3: -1.38904e-008

a4: 9.1287395e-011

a5: 1.6443535e-013

a6: 1.5776928e-016

a7: -1.906172e-018

a8: -2.4516764e-022;

The coefficient of the second surface S24 of the twelfth lens 12 is:

k: -0.3118853

a1:0

a2: -1.1445681e-005

a3: 3.0836874e-007

a4: -2.1372203e-009

a5: 4.7401379e-011

a6: -9.3909422e-014

a7: -8.6871391e-017

a8: -9.1956209e-019.

Claims (7)

1. A kind of ultra-short-focus projection optical system, it is characterized in that, on projection direction, be provided with successively: DMD chip (100), equivalent prism (110), refraction lens assembly (120) and aspheric reflector (130) ; The refracting lens assembly (120) includes a first lens (1), a second lens (2), a third lens (3), a fourth lens (4) and a fifth lens (5) arranged in sequence along the projection direction; Diaphragm (13), sixth lens (6), seventh lens (7), eighth lens (8), ninth lens (9), tenth lens (10), eleventh lens (11) and the first Twelve lenses (12). 2. A kind of ultra-short focus projection optical system according to claim 1, characterized in that, the refractive power of the first lens (1) is positive, and the refractive power of the second lens (2) is negative, the refractive power of the third lens (3) is positive, the refractive power of the fourth lens (4) is negative, the refractive power of the fifth lens (5) is positive, and the refractive power of the first The power of the six lenses (6) is negative, the power of the seventh lens (7) is positive, the power of the eighth lens (8) is negative, and the power of the ninth lens (9) The optical power of the tenth lens (10) is positive, the optical power of the eleventh lens (11) is positive, and the optical power of the twelfth lens (12) degree is negative. 3. A kind of ultra-short-focus projection optical system according to claim 2, characterized in that, the Abbe number vd ₂ of the second lens (2) and the Abbe number vd ₃ of the third lens (3) satisfy: 57 ≤vd ₃ -vd ₂ ≤60; the Abbe number vd ₃ of the third lens (3) and the Abbe number vd ₄ of the fourth lens (4) satisfy: 54≤vd ₃ -vd ₄ ≤57; the non The spherical reflector (130) is a convex even-order _aspheric surface, and its focal power satisfies: -0.035≤φ130≤-0.03. 4. A kind of ultra-short-focus projection optical system according to claim 2, characterized in that, the two sides of the twelfth lens (12) are bent towards the DMD chip (100), and the focal power satisfies: -0.013≤φ ₁₂ ≤ -0.012, the distance between the twelfth lens (12) and the DMD chip (100) is L, the distance between the DMD chip (100) and the center of the aspheric mirror (130) is LA, satisfying: L/LA>1.5. 5. A kind of ultra-short-focus projection optical system according to claim 1, characterized in that, the second lens (2) and the third lens (3) are bonded by optical glue, and the third lens (3) and the fourth lens (4) are bonded by optical glue. 6. A kind of ultra-short focus projection optical system according to claim 1, characterized in that, the first lens (1) is a glass aspheric surface, the twelfth lens (12) is a plastic aspheric surface, and the aspheric surface The reflecting mirror (130) is a plastic aspheric surface. 7. A kind of ultra-short focus projection optical system according to claim 1, characterized in that, the aspheric surfaces of the first lens (1), the twelfth lens (12) and the aspheric mirror (130) The surface shape of satisfies the following equation: The parameter c in the above equation is the curvature corresponding to the radius, y is the radial coordinate and its unit is the same as the lens length unit, and k is the conic conic conic coefficient; when the k coefficient is less than -1, the surface curve of the lens is a hyperbola; When the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is Circular, when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the even-order aspheric coefficients corresponding to each radial coordinate.