TWI687735B - Projection lens - Google Patents

Abstract

A projection lens includes a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group and a sixth lens group, all of which are arranged in order from a projection side to an image source side along an optical axis. The first lens group is with negative refractive power and includes a first lens. The second lens group is with positive refractive power. The third lens group is with positive refractive power. The fourth lens group is with negative refractive power. The fifth lens group is with positive refractive power. The sixth lens group is with positive refractive power. The projection lens satisfies the following condition: 0.4<R₁₂/f<2.5, wherein R₁₂ is a radius of curvature of an image source side surface of the first lens and f is is an effective focal length of the projection lens.

Description

Projection lens (12)

The invention relates to a projection lens.

Traditional projectors are large in size and not easy to carry. In recent years, projectors have gradually moved toward miniaturized designs in order to facilitate portability, so that the projection lenses used in them must also be miniaturized. In addition, in order to increase the brightness of the projector, the projection lens needs to have a larger aperture. On the other hand, in order to adjust the projection size without moving the position of the projector, the projection lens needs to have a zoom function. Therefore, the traditional projection lens can no longer meet the demand. A projection lens design with another architecture is needed to meet the requirements of miniaturization, large aperture and variable focal length.

In view of this, the main purpose of the present invention is to provide a projection lens, which has a smaller lens size, a smaller aperture value, and a zoom function, but still has good optical performance.

The projection lens of the present invention includes a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth in order along an optical axis from a projection side to an image source side A lens group and a sixth lens group. The first lens group has negative refractive power and includes a first lens, the second lens group has positive refractive power, the third lens group has positive refractive power, the fourth lens group has negative refractive power, the fifth lens group has positive refractive power, and the sixth lens group It has positive refractive power, where the projection lens satisfies the following conditions: 0.4<R ₁₂ /f<2.5; where R _{12 is a} radius of curvature of an image source side of one of the first lenses, and f is an effective focal length of the projection lens.

The projection lens of the present invention includes a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens in sequence along an optical axis from a projection side to an image source side Lens group. The first lens group has negative refractive power and includes a first lens, the second lens group has positive refractive power, the third lens group has positive refractive power, the fourth lens group has positive refractive power, and the fifth lens group has positive refractive power.

The projection lens includes a cemented lens, and the cemented lens includes two lenses, and the Abbe coefficient difference of these lenses is greater than 20.

The lens group between the first lens group and the image source side can move along the optical axis to change the focal length of the projection lens.

The projection lens satisfies the following conditions: 0.4<R ₁₂ /f<2.5; where R ₁₂ is a radius of curvature of one side of the image source of one of the first lenses, and f is one of the effective focal lengths of the projection lens.

The projection lens satisfies the following conditions: CRA<5 degrees; wherein, the chief rays of the projection lens for this projection lens reach an angle of an image source.

The projection lens satisfies the following conditions: F>1.5; where F is one of the aperture values of the projection lens.

The projection lens of the present invention may further include an aperture disposed between the third lens group and the fourth lens group.

The first lens group includes the first lens and a second lens in sequence along the optical axis from the projection side to the image source side, and the second lens group includes a third in sequence along the optical axis from the projection side to the image source side A lens and a fourth lens. The third lens group includes a fifth lens. The fourth lens group includes a sixth lens, a seventh lens, and an eighth lens in order from the projection side to the image source side along the optical axis. A ninth lens, a fifth lens group including a tenth lens, a sixth lens group including an eleventh lens, the first lens has negative refractive power, the first lens satisfies the following conditions: Vd ₁ >45; wherein, Vd _{1 This is} one of the Abbe coefficients of the first lens.

The first lens group includes the first lens and a second lens in sequence along the optical axis from the projection side to the image source side, and the second lens group includes a third in sequence along the optical axis from the projection side to the image source side A lens and a fourth lens. The third lens group includes a fifth lens. The fourth lens group includes a sixth lens, a seventh lens, and an eighth lens in order from the projection side to the image source side along the optical axis. A ninth lens and a tenth lens. The fifth lens group includes an eleventh lens. The first lens has negative refractive power. The first lens satisfies the following conditions: Vd ₁ >45; where Vd _{1 is the} first Abbe coefficient of one of the lenses.

Wherein the projection lens satisfies the following conditions: 0.72<R ₁₂ /f<1.18;60>Vd ₁ >45;1.5<F<2.2; where R _{12 is} one of the radius of curvature of one of the first lens image source sides, f Is an effective focal length of the projection lens, Vd _{1 is an} Abbe coefficient of the first lens, F is an aperture value of the projection lens, the projection lens includes a cemented lens, the cemented lens includes two lenses, the lenses The Abbe coefficient difference is greater than 20 and less than 55.

In order to make the above objects, features, and advantages of the present invention more comprehensible, preferred embodiments are described in detail below in conjunction with the accompanying drawings.

1, 2: projection lens

G11, G21: the first lens group

G12, G22: second lens group

G13, G23: third lens group

G14, G24: fourth lens group

G15, G25: Fifth lens group

G16: sixth lens group

L11, L21: the first lens

L12, L22: second lens

L13, L23: third lens

L14, L24: fourth lens

L15, L25: fifth lens

L16, L26: sixth lens

L17, L27: seventh lens

L18, L28: eighth lens

L19, L29: Ninth lens

L110, L210: tenth lens

L111, L211: Eleventh lens

ST1, ST2: aperture

OA1, OA2: optical axis

IS1, IS2: image source

PG1, PG2: glass plate

P1, P2: Lu Han

CG1, CG2: protective glass

S11, S12, S13, S14, S15, S16, S17: surface

S18, S19, S110, S111, S112, S113: surface

S114, S115, S116, S117, S118, S119: surface

S120, S121, S122, S123, S124, S125: surface

S126, S127: noodles

S21, S22, S23, S24, S25, S26, S27: surface

S28, S29, S210, S211, S212, S213: surface

S214, S215, S216, S217, S218, S219: surface

S220, S221, S222, S223, S224, S225: surface

S226, S227: noodles

D1 ₄₅ , D1 ₈₉ , D1 ₁₀₁₁ , D1 ₁₇₁₈ , D1 ₁₉₂₀ : pitch

D2 ₄₅ , D2 ₈₉ , D2 ₁₀₁₁ , D2 ₁₉₂₀ : pitch

FIG. 1 is a schematic diagram of the lens configuration and optical path at the wide-angle end of the first embodiment of the projection lens according to the present invention.

FIG. 2 is a schematic diagram of the lens configuration and optical path at the telephoto end according to the first embodiment of the projection lens of the present invention.

Figure 3A is the field curvature diagram of the projection lens of Figure 1.

Figure 3B is a distortion diagram of the projection lens of Figure 1.

Figure 3C is a relative illuminance diagram of the projection lens of Figure 1.

Figure 3D is a diagram of the modulation transfer function of the projection lens of Figure 1.

FIG. 3E is a diagram of the defocus modulation conversion function of the projection lens of FIG. 1.

Figure 3F is a diagram of the modulation conversion function of the projection lens of Figure 2.

Figure 3G is a graph of the defocus modulation transfer function of the projection lens of Figure 2.

FIG. 4 is a schematic diagram of the lens configuration and optical path at the wide-angle end of the second embodiment of the projection lens according to the present invention.

FIG. 5 is a schematic diagram of the lens configuration and optical path at the telephoto end of the second embodiment of the projection lens according to the present invention.

Figure 6A is the field curvature diagram of the projection lens of Figure 4.

Figure 6B is a distortion diagram of the projection lens of Figure 4.

Figure 6C is a relative illuminance diagram of the projection lens of Figure 4.

Figure 6D is a diagram of the modulation conversion function of the projection lens of Figure 4.

FIG. 6E is a diagram of the defocus modulation conversion function of the projection lens of FIG. 4.

Figure 6F is a diagram of the modulation conversion function of the projection lens of Figure 5.

Fig. 6G is a diagram of the defocus modulation conversion function of the projection lens of Fig. 5;

Please refer to FIG. 1 and FIG. 2, FIG. 1 is a schematic diagram of the lens configuration and optical path at the wide-angle end of the first embodiment of the projection lens according to the present invention, and FIG. 2 is the first embodiment of the projection lens according to the present invention at Schematic diagram of lens configuration and optical path at the telephoto end. During projection, light from an image source IS1 is finally projected on a projection side. The projection lens 1 includes a first lens group G11, a second lens group G12, a third lens group G13, an aperture ST1, and a fourth lens group in sequence along an optical axis OA1 from the projection side to an image source side G14, a fifth lens group G15, a sixth lens group G16, a glass plate PG1, a tin P1 and a protective glass CG1. By using the first lens group G11 and the image source IS1 distance between each lens group of D1 _{45, D1 89, D1 1011, D1} 1718, D1 1920 can achieve an effective change in focal length of the projection lens 1 to adjust the spacing D1 _45, D1 ₈₉ , D1 ₁₀₁₁ , D1 ₁₇₁₈ , and D1 _{1920 change} as the projection lens 1 zooms from the wide-angle end to the telephoto end, as can be clearly seen in Figures 1 and 2.

In the first embodiment, the first lens group G11 has negative refractive power, the second lens group G12 has positive refractive power, the third lens group G13 has positive refractive power, the fourth lens group G14 has negative refractive power, and the fifth lens group G15 has positive refractive power Refractive power, the sixth lens group G16 has positive refractive power.

The first lens group G11 includes a first lens L11 and a second lens L12 in order from the projection side to the image source side along the optical axis OA1. The first lens L11 is a meniscus lens, its projection side S11 is convex, the image source side S12 is concave, and both the projection side S11 and the image source side S12 are aspherical surfaces. The second lens L12 is a double concave lens, the projection side S13 is concave, the image source side S14 is concave, and both the projection side S13 and the image source side S14 are aspherical surfaces.

The second lens group G12 includes a third lens L13 and a fourth lens L14 in order from the projection side to the image source side along the optical axis OA1. The third lens L13 is a biconvex lens, its projection side S15 is convex, and the image source side S16 is convex and spherical. First The four lens L14 is a meniscus lens, and its projection side surface S17 is convex and spherical surface, and the image source side surface S18 is concave surface.

The third lens group G13 includes a fifth lens L15. The fifth lens L15 is a biconvex lens, its projection side S19 is convex, the image source side S110 is convex, and both the projection side S19 and the image source side S110 are spherical surfaces.

The fourth lens group G14 includes a sixth lens L16, a seventh lens L17, an eighth lens L18, and a ninth lens L19 in order from the projection side to the image source side along the optical axis OA1. The sixth lens L16 and the seventh lens L17 are cemented into a cemented lens, and the eighth lens L18 and the ninth lens L19 are cemented into a cemented lens. The sixth lens L16 is a biconvex lens, its projection side S112 is convex, the image source side S113 is convex, and both the projection side S112 and the image source side S113 are spherical surfaces. The seventh lens L17 is a biconcave lens, the projection side S113 is concave, the image source side S114 is concave, and the projection side S113 and the image source side S114 are both spherical surfaces. The eighth lens L18 is a biconcave lens, and its projection side S115 is concave, the image source side S116 is concave, and both the projection side S115 and the image source side S116 are spherical surfaces. The ninth lens L19 is a biconvex lens, its projection side S116 is convex, the image source side S117 is convex, and both the projection side S116 and the image source side S117 are spherical surfaces.

The fifth lens group G15 includes a tenth lens L110. The tenth lens L110 is a biconvex lens, its projection side S118 is convex, the image source side S119 is convex, and both the projection side S118 and the image source side S119 are spherical surfaces.

The sixth lens group G16 includes an eleventh lens L111. The eleventh lens L111 is a biconvex lens, its projection side S120 is convex, the image source side S121 is convex, and both the projection side S120 and the image source side S121 are spherical surfaces.

The projection side S122 and the image source side S123 of the glass plate PG1 are both flat.

The projection side S124 and the image source side S125 of the P1 are flat.

The projection side S126 and the image source side S127 of the protective glass CG1 are both flat.

In addition, in order to maintain good optical performance of the projection lens of the present invention, the projection lens 1 in the first embodiment satisfies at least one of the following conditions: |Vd1 ₆ -Vd1 ₇ |>20 (1)

|Vd1 ₈ -Vd1 ₉ |>20 (2)

Vd1 ₁ >45 (3)

0.4<R1 ₁₂ /f1 _W <2.5 (4)

0.4<R1 ₁₂ /f1 _T <2.5 (5)

CRA1 _W <5 degrees (6)

CRA1 _T <5 degrees (7)

F1 _W >1.5 (8)

F1 _T >1.5 (9)

Wherein, Vd1 ₁ is the Abbe number of the first lens L11, Vd1 ₆ of the sixth lens L16 Abbe, Vd1 ₇ is Abbe number of the lens L17 of the seventh, Vd1 ₈ is the Abbe number of the eighth lens L18, Vd1 ₉ is the Abbe coefficient of the ninth lens L19, R1 ₁₂ is a radius of curvature of the image source side S12 of the first lens L11, f1 _W is an effective focal length of the projection lens 1 at the wide-angle end, and f1 _T is the projection lens 1 at An effective focal length at the telephoto end, CRA1 _W is an angle at which the chief ray of the projection lens 1 at the wide-angle end reaches the image source IS1, CRA1 _T is an angle at which the chief ray of the projection lens 1 at the telephoto end reaches the image source IS1, and F1 _W is The aperture value of the projection lens 1 at the wide-angle end, F1 _T is the aperture value of the projection lens 1 at the telephoto end.

With the design of the lens and aperture ST1, the projection lens 1 can achieve a variable focal length, effectively reduce the volume, reduce the aperture value, correct aberrations, and improve the lens resolution to achieve good imaging quality.

Table 1 is the related parameter table of each lens when the projection lens 1 of FIGS. 1 and 2 is at the wide-angle end and the telephoto end, respectively. Table 1 shows that the effective focal length of the projection lens 1 of the first embodiment at the wide-angle end is equal to 14.3 mm, aperture value is equal to 1.81, the angle of the chief ray reaching the image source IS1 is equal to 1.1 degrees, the effective focal length at the telephoto end is equal to 22.9mm, the aperture value is equal to 2.1, the angle of the main ray reaching the image source IS1 is equal to 1.0 degrees, the projection lens 1 The zoom magnification is about 1.6 times. In Table 1, when the curvature of a surface is 0.00 (the radius of curvature is equal to 1/curvature, the radius of curvature tends to ∞), it means that the surface is a plane.

The aspherical surface concave degree z of each lens in Table 1 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴ +Gh ¹⁶

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~G: aspherical coefficient.

Table 2 is the related parameter table of the aspherical surface of each lens in Table 1, where k is the conic constant and A~G are the aspherical coefficients.

In the projection lens 1 of the first embodiment, the Abbe coefficient Vd1 _{1 of} the first lens L11 =58, the Abbe coefficient Vd1 _{6 of the} sixth lens L16 =61, and the Abbe coefficient Vd1 _{7 of the} seventh lens L17 =26, The Abbe coefficient Vd1 _{8 of the} eight lens L18 = 28, the Abbe coefficient Vd1 _{9 of the} ninth lens L19 = 81, the radius of curvature R1 ₁₂ of the image source side S12 of the first lens L11 = 16.67 mm, and the projection lens 1 at the wide-angle end Effective focal length f1 _w = 14.3 mm, effective focal length of projection lens 1 at the telephoto end f1 _T = 22.9 mm, angle of chief ray of projection lens 1 at the wide-angle end reaching image source IS1 CRA1 _W = 1.1 degrees, projection lens 1 at the telephoto end The angle of the chief ray reaching the image source IS1 is CRA1 _T = 1.0 degree, the aperture value of the projection lens 1 at the wide-angle end is F1 _W = 1.81, and the aperture value of the projection lens 1 at the telephoto end is F1 _T = 2.1. From the above data, Vd1 ₁ =58, |Vd1 ₆ -Vd1 ₇ |=35, |Vd1 ₈ -Vd1 ₉ |=53, R1 ₁₂ /f1 _W =1.17, R1 ₁₂ /f1 _T =0.73, CRA1 _W =1.1 Degrees, CRA1 _T = 1.0 degrees, F1 _W = 1.81, F1 _T = 2.1, all can meet the requirements of the above conditions (1) to (9).

In addition, the optical performance of the projection lens 1 of the first embodiment can also meet the requirements, which can be seen from FIGS. 3A to 3G. FIG. 3A is a field curvature diagram of the projection lens 1 of the first embodiment at the wide-angle end. FIG. 3B shows a distortion diagram of the projection lens 1 of the first embodiment at the wide-angle end. FIG. 3C is a diagram of the relative illumination (Relative Illumination) of the projection lens 1 of the first embodiment at the wide-angle end. FIG. 3D is a diagram of the modulation transfer function of the projection lens 1 of the first embodiment at the wide-angle end. FIG. 3E is a diagram of the Through Focus Modulation Transfer Function of the projection lens 1 of the first embodiment at the wide-angle end. FIG. 3F is a diagram of the modulation transfer function of the projection lens 1 of the first embodiment at the telephoto end. FIG. 3G is a diagram of the Through Focus Modulation Transfer Function of the projection lens 1 of the first embodiment at the telephoto end.

As can be seen from FIG. 3A, the projection lens 1 of the first embodiment opposes rays with wavelengths of 0.450 μm, 0.480 μm, 0.550 μm, 0.600 μm, and 0.630 μm at the wide-angle end, in the meridional (Tangential) direction and sagittal (Sagittal) ) The field curvature in the direction is between -0.06mm and 0.06mm between. As can be seen from Fig. 3B (the five lines in the figure almost overlap so that there is only one line), the projection lens 1 of the first embodiment has a wavelength of 0.450 μm, 0.480 μm, 0.550 μm, 0.600 μm at the wide-angle end The distortion caused by 0.630μm light is between -1.2% and 0%. It can be seen from FIG. 3C that the projection lens 1 of the first embodiment faces the light with a wavelength of 0.630 μm at the wide-angle end, and the relative illuminance between the Y field of view is between 0 mm and 8.3 mm, and is between 0.52 and 1.0. As can be seen from the 3D image, the projection lens 1 of the first embodiment opposes light with a wavelength range of 0.450 μm to 0.630 μm at the wide-angle end, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view They are 0.0000mm, -2.4900mm, -7.4700mm, and -8.3000mm respectively, the spatial frequency is between 0lp/mm and 93lp/mm, and the modulation transfer function value is between 0.54 and 1.0. It can be seen from FIG. 3E that the projection lens 1 of the first embodiment opposes light with a wavelength range of 0.450 μm to 0.630 μm at the wide-angle end, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view Respectively 0.0000mm, -2.4900mm, -4.1500mm, -7.4700mm, -8.3000mmmm, when the spatial frequency is equal to 93lp/mm, when the focus shift is between -0.44mm and 0.25mm, the modulation transfer function values are all Greater than 0.2. As can be seen from FIG. 3F, the projection lens 1 of the first embodiment opposes rays with a wavelength range of 0.4500 μm to 0.6300 μm at the telephoto end, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view They are 0.0000mm, -2.4900mm, -7.4700mm, and -8.300mm, the spatial frequency is between 0lp/mm and 93lp/mm, and the modulation transfer function value is between 0.50 and 1.0. As can be seen from FIG. 3G, the projection lens 1 of the first embodiment at the telephoto end has a wavelength range of 0.4500 μm to 0.6300 μm, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, the height of the field of view Respectively 0.0000mm, -4.1500mm, -5.8100mm, -7.4700mm, -8.83000mm, when the spatial frequency is equal to 93lp/mm, when the focus shift is between -0.028mm and 0.018mm, the modulation transfer function values are all more than the 0.2. It is obvious that the field curvature and distortion of the projection lens 1 of the first embodiment can be effectively corrected, and the relative illuminance, lens resolution, and depth of focus can also meet the requirements, thereby obtaining better optical performance.

To meet the conditions of the present invention is _{0.4 <R1 12 / f1 W <} 2.5,0.4 <R1 12 / f1 T <2.5, | Vd1 6 -Vd1 7 |> 20 or | Vd1 ₈ -Vd1 ₉ |> 20 as the center, according to the present invention The numerical values of the examples also fall within the range of the remaining conditions. In the present invention, the conditions 0.4<R1 ₁₂ /f1 _W <2.5, 0.4<R1 ₁₂ /f1 _T <2.5 represent that the light should be projected on the screen, so the effect of the R value will be more obvious when it reaches the front end, so that the light can be relatively small A relatively large angle is projected in the optical path, and the best effect range is 0.72<R ₁₂ /f<1.18. Conditions |Vd1 ₆ -Vd1 ₇ |>20 or |Vd1 ₈ -Vd1 ₉ |>20, which is the characteristic of lens chromatic aberration, using two consecutive lenses with large Vd drop to match, the best effect range is 55 >|Vd1 ₆ -Vd1 ₇ |>20, 55>|Vd1 ₈ -Vd1 ₉ |>20. The condition Vd1 ₁ >45 represents the material of the first lens, and its best effect range is 60>Vd1 ₁ >45. The condition CRA<5 degrees is the lens characteristics of this case, and the condition F>1.5 limits the luminous flux of the lens. The smaller the value, the greater the luminous flux, and the best effect range is 1.5<F<2.2.

Please refer to FIG. 4 and FIG. 5, FIG. 4 is a schematic diagram of a lens configuration and optical path at the wide-angle end of the second embodiment of the projection lens according to the present invention, and FIG. 5 is a second embodiment of the projection lens according to the present invention at Schematic diagram of lens configuration and optical path at the telephoto end. During projection, light from an image source IS2 is finally projected on a projection side. The projection lens 2 includes a first lens group G21, a second lens group G22, a third lens group G23, an aperture ST2, and a fourth lens group in sequence along an optical axis OA2 from the projection side to an image source side G24, a fifth lens group G25, a glass flat plate PG2, a glass P2 and a protective glass CG2. In use, the effective focal length of the projection lens 2 can be adjusted by changing the distances D2 ₄₅ , D2 ₈₉ , D2 ₁₀₁₁ , and D2 ₁₉₂₀ between the first lens group G21 and the image source IS2. The above-mentioned distances D2 ₄₅ , D2 ₈₉ , The situation where D2 ₁₀₁₁ and D2 _{1920 change} as the projection lens 2 zooms from the wide-angle end to the telephoto end can be clearly seen in Figures 4 and 5.

In the second embodiment, the first lens group G21 has negative refractive power, the second lens group G22 has positive refractive power, the third lens group G23 has positive refractive power, the fourth lens group G24 has positive refractive power, and the fifth lens group G25 has positive refractive power Refractive power.

The first lens group G21 sequentially includes a first lens L21 and a second lens L22 from the projection side to the image source side along the optical axis OA2. The first lens L21 is a meniscus lens, its projection side S21 is convex, the image source side S22 is concave, and both the projection side S21 and the image source side S22 are aspherical surfaces. The second lens L22 is a biconcave lens, its projection side S23 is concave, the image source side S24 is concave, and both the projection side S23 and the image source side S24 are aspherical surfaces.

The second lens group G22 includes a third lens L23 and a fourth lens L24 in order from the projection side to the image source side along the optical axis OA2. The third lens L23 is a biconvex lens, its projection side S25 is convex, and the image source side S26 is convex and spherical. The fourth lens L24 is a meniscus lens, its projection side surface S27 is convex and spherical surface, and the image source side surface S28 is concave surface.

The third lens group G23 includes a fifth lens L25. The fifth lens L25 is a biconvex lens, its projection side S29 is convex, the image source side S210 is convex, and both the projection side S29 and the image source side S210 are spherical surfaces.

The fourth lens group G24 includes, in order from the projection side to the image source side along the optical axis OA2, a sixth lens L26, a seventh lens L27, an eighth lens L28, a ninth lens L29, and a tenth lens L210 . Sixth lens L26 and seventh lens L27 A cemented cemented lens, an eighth lens L28 and a ninth lens L29 are cemented into a cemented lens. The sixth lens L26 is a biconvex lens, its projection side S212 is convex, the image source side S213 is convex, and both the projection side S212 and the image source side S213 are spherical surfaces. The seventh lens L27 is a biconcave lens, and its projection side S213 is concave, the image source side S214 is concave, and both the projection side S213 and the image source side S214 are spherical surfaces. The eighth lens L28 is a biconcave lens, and its projection side S215 is concave, the image source side S216 is concave, and both the projection side S215 and the image source side S216 are spherical surfaces. The ninth lens L29 is a biconvex lens, its projection side S216 is convex, the image source side S217 is convex, and both the projection side S216 and the image source side S217 are spherical surfaces. The tenth lens L210 is a biconvex lens, its projection side S218 is convex, the image source side S219 is convex, and both the projection side S218 and the image source side S219 are spherical surfaces.

The fifth lens group G25 includes an eleventh lens L211. The eleventh lens L211 is a biconvex lens, its projection side S220 is convex, the image source side S221 is convex, and both the projection side S220 and the image source side S221 are spherical surfaces.

The projection side S222 and the image source side S223 of the glass plate PG2 are both flat.

The projection side S224 and the image source side S225 of the P2 are flat.

The projection side S226 and the image source side S227 of the protective glass CG2 are both flat.

In addition, in order to maintain good optical performance of the projection lens of the present invention, the projection lens 2 in the second embodiment satisfies at least one of the following conditions: |Vd2 ₆ -Vd2 ₇ |>20 (10)

|Vd2 ₈ -Vd2 ₉ |>20 (11)

Vd2 ₁ >45 (12)

0.4<R2 ₁₂ /f2 _W <2.5 (13)

0.4<R2 ₁₂ /f2 _T <2.5 (14)

CRA2 _W <5 degrees (15)

CRA2 _T <5 degrees (16)

F2 _W >1.5 (17)

F2 _T >1.5 (18)

Wherein, Vd2 ₁ is the Abbe number of the first lens L21, Vd2 ₆ of the sixth lens L26 Abbe, Vd2 ₇ is Abbe number of the lens L27 of the seventh, Vd2 ₈ is the Abbe number of the eighth lens L28, Vd2 ₉ is the Abbe coefficient of the ninth lens L29, R2 ₁₂ is a radius of curvature of the image source side S22 of the first lens L21, f2 _W is an effective focal length of the projection lens 2 at the wide-angle end, and f2 _T is the projection lens 2 at One of the effective focal lengths at the telephoto end, CRA2 _W is the angle at which the chief ray of projection lens 2 at the wide-angle end reaches image source IS2, CRA2 _T is the angle at which the chief ray of projection lens 2 at the telephoto end reaches image source IS2, and F2 _W is The aperture value of the projection lens 2 at the wide-angle end, F2 _T is the aperture value of the projection lens 2 at the telephoto end.

With the design of the lens and the aperture ST2, the projection lens 2 can achieve a variable focal length, effectively reduce the volume, reduce the aperture value, correct aberrations, and improve the lens resolution to achieve good imaging quality.

Table 3 is the relevant parameter table of each lens when the projection lens 2 of FIGS. 4 and 5 is at the wide-angle end and the telephoto end, respectively. The data in Table 3 shows that the effective focal length of the projection lens 2 of the second embodiment at the wide-angle end is equal to 14.3 mm, the aperture value is equal to 1.75, the angle of the chief ray reaching the image source IS2 is equal to 1.4 degrees, the effective focal length at the telephoto end is equal to 21.8mm, the light The circle value is equal to 1.95, the angle at which the chief ray reaches the image source IS2 is equal to 1.35 degrees, and the zoom magnification of the projection lens 2 is approximately 1.5 times.

The formula of the aspherical surface depression degree z of each lens in Table 3 is the same as the aspherical surface depression degree z applicable to Table 1 above. For the physical meaning of each parameter, please refer to the description of Table 1 aspherical surface depression degree z formula. This will not be repeated.

Table 4 is the related parameter table of the aspherical surface of each lens in Table 3.

In the projection lens 2 of the second embodiment, the Abbe coefficient Vd2 ₁ = 58 of the first lens L21, the Abbe coefficient Vd2 ₆ = 60 of the sixth lens L26, and the Abbe coefficient Vd2 ₇ = 25 of the seventh lens L27, The Abbe coefficient Vd2 ₈ = 25 of the eight lens L28, the Abbe coefficient Vd2 ₉ = 64 of the ninth lens L29, the radius of curvature R2 ₁₂ of the image source side S22 of the first lens L21 ₁₂ = 16.67 mm, and the projection lens 2 at the wide angle end Effective focal length f2 _w = 14.3 mm, effective focal length of projection lens 2 at the telephoto end f2 _T = 21.8 mm, angle of chief ray of projection lens 2 at the wide-angle end reaching image source IS2 CRA2 _W = 1.4 degrees, projection lens 2 at the telephoto end The angle at which the chief ray reaches the image source IS2 is CRA2 _T = 1.35 degrees, the aperture value of the projection lens 2 at the wide-angle end is F2 _W = 1.75, and the aperture value of the projection lens 2 at the telephoto end is F2 _T = 1.95. From the above data, Vd2 ₁ =58, |Vd2 ₆ -Vd2 ₇ |=35, |Vd2 ₈ -Vd2 ₉ |=39, R2 ₁₂ /f2 _W =1.17, R2 ₁₂ /f2 _T =0.76, CRA2 _W =1.4 Degrees, CRA2 _T = 1.35 degrees, F2 _W = 1.75, F2 _T = 1.95, all can meet the requirements of the above conditions (10) to (18).

In addition, the optical performance of the projection lens 2 of the second embodiment can also meet the requirements, This can be seen from Figures 6A to 6G. FIG. 6A is a field curvature diagram of the projection lens 2 of the second embodiment at the wide-angle end. FIG. 6B is a distortion diagram of the projection lens 2 of the second embodiment at the wide-angle end. FIG. 6C is a diagram of the relative illumination (Relative Illumination) of the projection lens 2 of the second embodiment at the wide-angle end. FIG. 6D shows a modulation transfer function (Modulation Transfer Function) of the projection lens 2 of the second embodiment at the wide-angle end. FIG. 6E is a diagram of the Through Focus Modulation Transfer Function of the projection lens 2 of the second embodiment at the wide-angle end. Shown in FIG. 6F is a modulation transfer function (Modulation Transfer Function) diagram of the projection lens 2 of the second embodiment at the telephoto end. FIG. 6G is a diagram of a Through Focus Modulation Transfer Function of the projection lens 2 of the second embodiment at the telephoto end.

As can be seen from FIG. 6A, the projection lens 2 of the second embodiment opposes the light rays with wavelengths of 0.450 μm, 0.480 μm, 0.486 μm, 0.550 μm, 0.588 μm, 0.600 μm, 0.630 μm, and 0.656 μm at the wide angle end. The field curvature between the (Tangential) direction and the sagittal direction is between -0.02mm and 0.07mm. As can be seen from Figure 6B (the eight lines in the figure almost overlap so that there is only one line), the projection lens 2 of the second embodiment has a wavelength of 0.450 μm, 0.480 μm, 0.486 μm, 0.550 at the wide-angle end The distortion caused by light of μm, 0.588μm, 0.600μm, 0.630μm, 0.656μm is between -1.2% and 0%. It can be seen from FIG. 6C that the projection lens 2 of the second embodiment faces the light with a wavelength of 0.480 μm at the wide-angle end, and the relative illuminance between the Y field of view is 0 mm to 8.3 mm and the range is 0.64 to 1.0. As can be seen from FIG. 6D, the projection lens 2 of the second embodiment opposes light with a wavelength range of 0.450 μm to 0.6563 μm at the wide-angle end, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view Respectively 0.0000mm, -2.4900mm, -7.4700mm, -8.83000mm, empty The inter-frequency is between 0lp/mm and 93lp/mm, and its modulation transfer function value is between 0.57 and 1.0. As can be seen from FIG. 6E, the projection lens 2 of the second embodiment opposes light with a wavelength range of 0.4500 μm to 0.6563 μm at the wide-angle end, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view Respectively 0.0000mm, -0.8300mm, -5.8100mm, -7.4700mm, -8.3000mm, when the spatial frequency is equal to 93lp/mm, when the focus shift is between -0.016mm and 0.013mm, the modulation conversion function values are all Greater than 0.2. As can be seen from FIG. 6F, the projection lens 2 of the second embodiment at the telephoto end has a wavelength range of 0.4500 μm to 0.6563 μm, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view They are 0.0000mm, -2.4900mm, -7.4700mm, and -8.300mm respectively, the spatial frequency is between 0lp/mm and 93lp/mm, and the modulation transfer function value is between 0.37 and 1.0. As can be seen from FIG. 6G, the projection lens 2 of the second embodiment opposes rays with a wavelength range of 0.450 μm to 0.6563 μm at the telephoto end, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the height of the field of view Respectively 0.0000mm, -2.4900mm, -4.1500mm, -7.4700mm, -8.83000mm, when the spatial frequency is equal to 93lp/mm, when the focus shift is between -0.022mm and 0.018mm, the modulation transfer function values are all Greater than 0.2. It is obvious that the field curvature and distortion of the projection lens 2 of the second embodiment can be effectively corrected, and the relative illuminance, lens resolution, and focal depth can also meet the requirements, thereby obtaining better optical performance.

To meet the conditions of the present invention is _{0.4 <R2 12 / f2 W <} 2.5,0.4 <R2 12 / f2 T <2.5, | Vd2 6 -Vd2 7 |> 20 or | Vd2 ₈ -Vd2 ₉ |> 20 as the center, according to the present invention The numerical values of the examples also fall within the range of the remaining conditions. In the present invention, the condition 0.4<R2 ₁₂ /f2 _W <2.5, 0.4<R2 ₁₂ /f2 _T <2.5 represents that the light should be projected on the screen, so the effect of the R value will be more obvious when it reaches the front end, so that the light can be relatively small A relatively large angle is projected in the optical path, and the best effect range is 0.72<R ₁₂ /f<1.18. Conditions |Vd2 ₆ -Vd2 ₇ |>20 or |Vd2 ₈ -Vd2 ₉ |>20, which is the characteristic of lens chromatic aberration, using two consecutive lenses with large Vd drop to match, the best effect range is 55 >|Vd2 ₆ -Vd2 ₇ |>20, 55>|Vd2 ₈ -Vd2 ₉ |>20. The condition Vd2 ₁ >45 represents the material of the first lens, and the best effect range is 60>Vd2 ₁ >45. The condition CRA<5 degrees is the lens characteristics of this case, and the condition F>1.5 limits the luminous flux of the lens. The smaller the value, the greater the luminous flux, and the best effect range is 1.5<F<2.2.

1: projection lens

G11: First lens group

G12: Second lens group

G13: third lens group

G14: fourth lens group

G15: Fifth lens group

G16: sixth lens group

L11: the first lens

L12: second lens

L13: third lens

L14: fourth lens

L15: Fifth lens

L16: sixth lens

L17: seventh lens

L18: Eighth lens

L19: Ninth lens

L110: Tenth lens

L111: Eleventh lens

ST1: Aperture

OA1: Optical axis

IS1: Image source

PG1: glass tablet

P1: 稜鏡

CG1: protective glass

S11, S12, S13, S14, S15, S16, S17: surface

S18, S19, S110, S111, S112, S113: surface

S114, S115, S116, S117, S118, S119: surface

S120, S121, S122, S123, S124, S125: surface

S126, S127: noodles

D1 ₄₅ , D1 ₈₉ , D1 ₁₀₁₁ , D1 ₁₇₁₈ , D1 ₁₉₂₀ : pitch

Claims (11)

A projection lens is mainly composed of a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group and a sixth lens group, wherein: the first lens The group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the sixth lens group are sequentially arranged from a projection side to an image source side along an optical axis; The first lens group has negative refractive power and is composed of a first lens and a second lens. The first lens and the second lens are arranged in sequence along the optical axis from the projection side to the image source side; the first The second lens group has positive refractive power; the third lens group has positive refractive power; the fourth lens group has negative refractive power, the fourth lens group includes a plurality of lenses; the fifth lens group has positive refractive power; the sixth lens group has Positive refractive power; the projection lens satisfies the condition: 0.4<R ₁₂ /f<2.5, where R _{12 is a} radius of curvature of the side of the image source of one of the first lenses, and f is an effective focal length of the projection lens; the first The second lens group, the third lens group, the fourth lens group, and the fifth lens group between the lens group and the image source side can be moved along the optical axis to change the effective focal length of the projection lens . A projection lens, along an optical axis, from a projection side to an image source side in sequence includes: a first lens group having a negative refractive power and including a first lens; a second lens group, the The second lens group has positive refractive power; a third lens group with positive refractive power; a fourth lens group with positive refractive power and from the projection side to the image along the optical axis The source side includes, in order, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens; and a fifth lens group, the fifth lens group has positive refractive power ; wherein the projection lens The following conditions are satisfied: 0.4<R ₁₂ /f<2.5; where R _{12 is a} radius of curvature of one side of the image source of one of the first lenses, and f is an effective focal length of one of the projection lenses. The projection lens as described in Item 1 or Item 2 of the patent application scope, wherein two adjacent lenses of the fourth lens group are cemented into a cemented lens, and the Abbe coefficient difference of the adjacent lenses is greater than 20. The projection lens as described in item 2 of the patent application range, wherein the second lens group, the third lens group, and the fourth lens group between the first lens group and the image source side can be along the optical axis Move to change the effective focal length of one of the projection lenses. A projection lens, along an optical axis, from a projection side to an image source side in sequence includes: a first lens group having a negative refractive power and including a first lens; a second lens group, the The second lens group has positive refractive power; a third lens group with positive refractive power; a fourth lens group with positive refractive power and from the projection side to the image along the optical axis The source side includes, in order, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens; and a fifth lens group, the fifth lens group having positive refractive power; The projection lens satisfies the following conditions: CRA<5 degrees; wherein, CRA is an angle at which the chief ray of the projection lens reaches an image source. The projection lens as described in item 1 or 2 of the patent application scope, wherein the projection lens satisfies the following conditions: CRA<5 degrees; wherein, CRA is an angle at which the chief ray of the projection lens reaches an image source. The projection lens as described in item 1 or 2 of the patent application scope, wherein the projection lens satisfies the following conditions: F>1.5; wherein, F is one of the aperture values of the projection lens. The projection lens as described in Item 1 or Item 2 of the patent application scope further includes an aperture disposed between the third lens group and the fourth lens group. The projection lens as described in item 1 of the patent application scope, wherein the second lens group is composed of a third lens and a fourth lens, and the third lens and the fourth lens project from the projection along the optical axis The third lens group is composed of a fifth lens, and the fourth lens group is composed of a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The sixth lens, the seventh lens, the eighth lens, and the ninth lens are sequentially arranged along the optical axis from the projection side to the image source side, and the fifth lens group is composed of a tenth lens The sixth lens group consists of an eleventh lens. The first lens has negative refractive power. The first lens satisfies the following conditions: Vd ₁ >45; where Vd _{1 is} Abbe, _{one of} the first lenses coefficient. The projection lens as described in item 2 or 5 of the patent application scope, wherein the first lens group includes the first lens and a second lens in order from the projection side to the image source side along the optical axis, The second lens group includes a third lens and a fourth lens in sequence along the optical axis from the projection side to the image source side, the third lens group includes a fifth lens, and the fifth lens group includes a An eleventh lens. The first lens has negative refractive power. The first lens satisfies the following condition: Vd ₁ >45; wherein, Vd _{1 is an} Abbe coefficient of one of the first lenses. The projection lens as described in item 1 or item 2 or item 5 of the patent application scope, wherein the projection lens satisfies the following conditions: 0.72<R ₁₂ /f<1.18;60>Vd ₁ >45;1.5<F<2.2; Where R _{12 is a} radius of curvature of a side of the image source of the first lens, f is an effective focal length of the projection lens, Vd _{1 is an} Abbe coefficient of the first lens, and F is one of the projection lenses Aperture value, two adjacent lenses of the fourth lens group are cemented into a cemented lens, and the Abbe coefficient difference of the adjacent lenses is greater than 20 and less than 55.

Images