TWI442085B - Projection lens and projection apparatus - Google Patents

Description

Projection lens and projection device

The present invention relates to an optical device, and more particularly to a projection lens having a large aperture and high imaging quality and a projection device to which the projection lens is applied.

Among many types of display devices, the projection device has a characteristic of projecting a large-sized image image that is several times larger than the surface area of the device with a small device volume, and thus has an advantage that it cannot be replaced in the display field. Since the projection device projects the image beam converted by the light valve onto the screen by the projection lens, the quality of the image is greatly affected by the quality of the projection lens. Therefore, the projection lens is a key optical component in the projection device.

In general, the projection lens has a variable zoom function. With the zoom function of the projection lens, the projection device can achieve the effect of scaling the image. Currently, the mainstream of projection devices is designed for high brightness. One way to achieve high brightness is to make the projection lens use a large aperture design. However, the projection lens with zoom function is complicated and limited by the stricter tolerance requirements, so it is difficult to achieve large aperture and high image quality at the same time.

For example, the F-numbers disclosed in U.S. Patent Nos. 7,253,966, US Pat. No. 7,038,857, U.S. Patent No. 5, 936, 780, U.S. Patent No. 7, 061, 688, and U.S. Patent No. 6,147, 812 are all above 2.4, that is, the characteristics of the aperture are small, so that the problem of insufficient luminous flux is apt to occur. US Patent Publication No. US 2011/0205637 discloses a zoom lens comprising two lens groups and using at least one aspheric lens. A zoom lens including at least two lens groups is also disclosed in the Republic of China Patent Publication No. I274895 and the Republic of China Patent Publication No. 556000. In addition, U.S. Patent No. 6,906,867 discloses a lens of a multi-zoom group comprising four lens groups.

The present invention provides a projection lens having a large aperture and high imaging quality.

The present invention provides a projection apparatus to which the projection lens is applied, which has high brightness and high projection quality.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

In order to achieve one or a portion or all of the above or other objects, an embodiment of the present invention provides a projection lens. The projection lens is used to project an image beam. The projection lens includes a first lens group and a second lens group. The first lens group is disposed between the image side and the object side and is located on the transmission path of the image beam, and has a negative refracting power, and includes at least four lenses. The second lens group is located on the transmission path of the image beam and is disposed between the first lens group and the object side. The second lens group has positive diopter, the second lens group includes at least six lenses and includes at least one aspheric lens, and the first lens group and the second lens group are relatively movable between the image side and the object side for zooming, The F-number of the projection lens is less than or equal to 2

Another embodiment of the present invention provides a projection apparatus including a lighting unit, a light valve, and the above-described projection lens. The illumination unit is used to provide an illumination beam. The light valve is disposed on the transmission path of the illumination beam, and is configured to convert the illumination beam into an image beam. The projection lens is disposed on the transmission path of the image beam, and the projection lens is located on the transmission path of the image beam for projecting the image. beam.

In an embodiment of the invention, the projection lens described above satisfies the following relationship:

0.53<∣f2/f1∣<0.69;

1.98<∣f1/fw∣<2.66;

1.36<∣f2/fw∣<1.42;

Where f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and fw is the effective focal length of the projection lens at the wide-angle end.

In an embodiment of the invention, the first lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens from the image side to the object side.

In an embodiment of the invention, the diopter of the first lens, the second lens, the third lens, and the fourth lens are positive, negative, negative, and positive.

In an embodiment of the invention, the first lens is a lenticular lens, the second lens is a convex-concave lens with a concave surface facing the object side, the third lens is a double concave lens, and the fourth lens is a lenticular lens.

In an embodiment of the present invention, the second lens group sequentially includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens from the image side to the object side, wherein the aspheric surface The lens may be a fifth lens, a sixth lens, a seventh lens, an eighth lens, or a ninth lens.

In an embodiment of the invention, the tenth lens has a negative refracting power.

In an embodiment of the present invention, the diopter of the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are positive, positive, positive, and negative, respectively. Positive and negative values.

In an embodiment of the invention, the fifth lens is a concave-convex lens having a concave surface facing the object side, the sixth lens is a concave-convex lens having a concave surface facing the object side, the seventh lens is a lenticular lens, and the eighth lens is a pair. The concave lens, the ninth lens is a lenticular lens, and the tenth lens is a convex-concave lens with a concave surface facing the object side.

In an embodiment of the invention, the seventh lens and the eighth lens form a cemented lens.

In an embodiment of the invention, the projection lens further includes an aperture stop disposed between the eighth lens and the ninth lens.

In an embodiment of the invention, the position of the second lens group is fixed, and the first lens group is movable relative to the second lens group.

Based on the above, in the projection lens and the projection apparatus of the embodiment of the present invention, the effect of zooming can be achieved by the relative displacement between the first lens group of negative refracting power and the second lens group of positive refracting power. Moreover, by arranging at least one aspherical mirror in the second lens group, the projection lens can still have good imaging quality under a small F-number, thereby providing the projection device with high brightness and excellent projection quality.

The above described features and advantages of the invention will be apparent from the following description.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only directions referring to the additional schema. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1A and FIG. 1B are respectively schematic diagrams showing optical structures of a projection apparatus at different zoom magnifications according to an embodiment of the invention. 1A illustrates an optical structure when the projection lens of the projection device is at a wide-end end, and FIG. 1B illustrates an optical structure when the projection lens of the projection device is at a tele-end. Referring to FIGS. 1A and 1B , the projection apparatus 1000 of the present embodiment includes a lighting unit 210 , a light valve 220 , a projection lens 100 , and a screen 50 . The illumination unit 210 is configured to provide an illumination beam L1. In this embodiment, the lighting unit 210 can be any device for illuminating the light valve 220. The light valve 220 is disposed on the transmission path of the illumination light beam L1 and is used to convert the illumination light beam L1 into the image light beam L2. In this embodiment, the light valve 220 is, for example, a digital micro-mirror device (DMD), a liquid-crystal-on-silicon panel, or other suitable spatial light modulator (spatial). Light modulator, SLM), etc.

2A and 2B are schematic views showing the optical structure of the projection lens shown in Figs. 1A and 1B, respectively. 2A illustrates an optical structure when the projection lens is at a wide-end end, and FIG. 2B illustrates an optical structure when the projection lens is at a tele-end. Referring to FIGS. 1A-1B and 2A-2B, the projection lens 100 of the present embodiment is disposed between the image side and the object side. In the projection device 1000, the image side corresponds to the screen 50, and the object side corresponds to the light valve 220. The projection lens is located on the transmission path of the image light beam L2 for projecting the image light beam L2 from the light valve 220 onto the screen 50 to form an image frame (not shown) on the screen 50. The projection lens 100 includes a first lens group 110 and a second lens group 120. The first lens group 110 is disposed between the screen 50 and the light valve 220, and the second lens group 120 is disposed between the first lens group 110 and the light valve 220. . The first lens group 110 has a negative power. The second lens group 120 has a positive refracting power. The projection lens 100 of the present embodiment has an F-number (F-number) of less than or equal to 2, and thus has an optical characteristic of a large aperture. In addition, a light-transmissive protective cover 230, such as a cover glass, may be disposed between the second lens group 120 and the light valve 220 to protect the light valve 220.

In the present embodiment, the first lens group 110 and the second lens group 120 are relatively movable between the light valve 220 and the screen 50 along the optical axis X. In other words, by the combination of the first lens group 110 and the second lens group 120, the projection apparatus 1000 of the present embodiment can have a function of focusing. The first lens group 110 and the second lens group 120 of the present embodiment have a variable distance D8 between them, and the second lens group 120 and the light valve 220 have a variable distance D20 therebetween, and the focal length of the first lens group 120 is F1, and the focal length of the second lens group is f2, and the projection lens 100 in which the first lens group 110 and the second lens group 120 are combined has an effective focal length f. When the relative distance between the first lens group 110 and the second lens group 120 is changed, the effective focal length f of the projection lens 100 can be changed accordingly, thereby allowing the projection device 1000 to have the effect of scaling the image size.

Referring to FIG. 1A, when the magnification of the projection apparatus 1000 of the present embodiment is to be large, the first lens group 110 may move toward the screen 50, and the second lens group 120 may move toward the light valve 220. At this time, the variable distance D8 between the first lens group 110 and the second lens group 120 becomes larger, and the variable distance D20 between the second lens group 120 and the light valve 220 becomes smaller, which is called the wide-angle end ( Wide-end). Referring to FIG. 1B, when the magnification of the projection apparatus 1000 of the present embodiment is to be small, the first lens group 110 may move toward the light valve 220, and the second lens group 120 may move toward the screen 50. At this time, the variable distance D8 between the first lens group 110 and the second lens group 120 becomes smaller, and the variable distance D20 between the second lens group 120 and the light valve 220 becomes larger, which is the telephoto end (Tele -end). In addition, when the projection distance (ie, the distance between the first lens group 110 and the screen 50) is changed, the first lens group 110 can be finely moved along the optical axis X with respect to the second lens group 120 to focus, and the screen 50 is made. The image on the screen is blurred from blur.

The composition of each lens group of the projection lens 100 of the present embodiment will be exemplified below, but it is not intended to limit the present invention.

Referring to FIGS. 2A and 2B, the first lens group 110 may include four lenses. In detail, the first lens group 110 sequentially includes the first lens 111, the second lens 112, the third lens 113, and the fourth lens 114 from the image side to the object side. In this embodiment, the diopter of the first lens 111, the second lens 112, the third lens 113, and the fourth lens 114 may be positive, negative, negative, and positive. In the present embodiment, the first lens 111 is, for example, a lenticular lens, the second lens 112 is, for example, a convex-concave lens having a concave surface toward the object side, the third lens 113 is, for example, a biconcave lens, and the fourth lens 114 is, for example, a lenticular lens. However, the present invention is not limited thereto, and the number of lenses, the shape of the lens, and the optical characteristics of the first lens group 110 may be differently designed according to actual needs.

The second lens group 120 of the present embodiment may include six lenses. In detail, the second lens group 120 sequentially includes the fifth lens 121, the sixth lens 122, the seventh lens 123, the eighth lens 124, the ninth lens 125, and the tenth lens 126 from the image side to the object side. In this embodiment, the refracting powers of the fifth lens 121, the sixth lens 122, the seventh lens 123, the eighth lens 124, the ninth lens 125, and the tenth lens 126 may be positive, positive, positive, Negative, positive, and negative values. In this embodiment, the fifth lens 121 may be a concave-convex lens whose concave surface faces the object side, the sixth lens 122 may be a concave-convex lens whose concave surface faces the object side, the seventh lens 123 may be a lenticular lens, and the eighth lens 124 may be a double lens. The concave lens, the ninth lens 125 may be a lenticular lens, and the tenth lens 126 may be a convex-concave lens having a concave surface toward the object side. Further, the seventh lens 123 and the eighth lens 124 may be connected to each other to constitute a cemented lens.

It is worth mentioning that in the embodiment, the second lens group 120 includes at least one aspheric lens. Further, in the present embodiment, the ninth lens 125 is an aspherical lens. However, the present invention is not limited thereto. In other embodiments, the fifth lens 121, the sixth lens 122, the seventh lens 123, or the eighth lens 124 may also be an aspherical lens. Since the aspherical lens can correct the light passing through the edge of the lens, the aspherical lens in the second lens group 120 of the present embodiment can effectively reduce the degree of aberration generated by the projection lens 100, thereby improving the optical performance of the projection lens 100. .

The projection lens 100 of the present embodiment may further include an aperture stop (A.S.) 240. In the present embodiment, the aperture stop 240 is located in the second lens group 120. In more detail, the aperture stop 240 is disposed between the eighth lens 124 and the ninth lens 125 to control the amount of incident light. When the aperture of the aperture stop 240 is larger, the projection lens 100 can correspond to a smaller F value (F-number). Further, the small F value (F-number) can represent an increase in the amount of incident light and a high luminance. However, the light entering the projection lens 100 at this time and away from the optical axis X of the projection lens 100 also increases at the same time, thereby causing aberration problems. In this embodiment, since the aperture stop 240 can be disposed between the eighth lens 124 and the ninth lens 125 which are closer to the light valve 220, the aperture stop 240 can filter out part of the light away from the optical axis X, thereby The projection lens 100 of the present embodiment has excellent optical characteristics.

The projection lens 100 of the present embodiment can also satisfy the following relationship to optimize the projection quality of the projection apparatus 1000, and the various design parameters satisfy the following conditions. These conditions are:

(1) 0.53<∣f2/f1∣<0.69;

(2) 1.98<∣f1/fw∣<2.66;

(3) 1.36<∣f2/fw∣<1.42;

Where fw is the effective focal length of the projection lens 100 at the wide-end end (wide-end). F1 is the effective focal length of the first lens group 120, and f2 is the effective focal length of the second lens group 120.

An embodiment of the projection lens 100 will be described below. It should be noted that the data sheets listed in Table 1 below are not intended to limit the present invention, and those having ordinary knowledge in the art can appropriately change their parameters or settings after referring to the present invention. However, it should still fall within the scope of the invention.

In Table 1, the radius of curvature (mm) refers to the radius of curvature of the corresponding surface, and the pitch (mm) refers to the linear distance between the two adjacent surfaces on the optical axis X. For example, the distance between the surfaces S1, that is, the distance between the surface S1 and the surface S2, the thickness, refractive index and Abbe number of each lens and each optical element in the remark column, please refer to the spacing, refractive index and the same in the same column. The number corresponding to the number of bets. The surfaces S1, S2 are the two surfaces of the first lens 111. The surfaces S3, S4 are the two surfaces of the second lens 112. The surfaces S5 and S6 are both surfaces of the third lens 113. The surfaces S7, S8 are the two surfaces of the fourth lens 114. The above four lenses constitute the first lens group 110.

Next, the surfaces S9 and S10 are the both surfaces of the fifth lens 121. The surfaces S11 and S12 are both surfaces of the sixth lens 121. The surface S13 is a surface on the image side of the seventh lens 122, the surface S14 is a surface on which the seventh lens 122 and the eighth lens 123 are connected, and the surface S15 is a surface on the object side of the eighth lens 123. The surface S16 is an aperture stop 240. The surfaces S17 and S18 are the two surfaces of the ninth lens 125. The surfaces S19 and S20 are the two surfaces of the tenth lens 126. The above six lenses constitute the second lens group 120. For the parameter values such as the radius of curvature and the spacing of each surface, please refer to Table 1, and will not be repeated here.

It should be noted that the ninth lens 125 described above is an aspherical lens, and the surfaces S17 and S18 thereof are aspherical, and the non-spherical formula is as follows:

Where Z is the offset of the optical axis direction (sag.), c is the reciprocal of the radius of the osculating sphere, that is, the radius of curvature close to the optical axis X (such as the curvature of S17, S18 in Table 1) The reciprocal of the radius). K is the quadric coefficient (conic). y is the aspherical height, which is the height from the center of the lens toward the edge of the lens, and A, B, C, and D are aspheric coefficients. Listed in Table 2 are the parameter values of surface S17 and surface S18.

In Table 3, some important parameter values D8 and D20 of the projection lens 100 at the wide-angle end and the telephoto end are respectively listed. Here, D8 is a variable distance between the first lens group 110 and the second lens group 120, that is, a distance between the surface S8 of the fourth lens 114 and the surface S9 of the fifth lens 121. D20 is a variable distance between the first lens group 110 and the light valve 220, and more precisely, D20 is the distance between the surface S20 of the tenth lens 126 and the surface of the light-transmitting protective cover 230. In this embodiment, D8 and D20 are adjustable, so as to achieve the effect of zooming (for example, a zoom effect of 1.2 times). For example, when D8 is 15.456 mm and D20 is 25.910 mm, the projection lens 100 can be at the wide-angle end (ie, having a magnification effect). When D8 is 1.215 mm and D20 is 30.044 mm, the projection lens 100 can be at the telephoto end (ie, has a reduction effect). Further, the F-number of the projection lens 100 of the present embodiment is, for example, 1.77, and conforms to the optical parameter conditions (1) to (3) described above, for example.

3A and 3B are diagrams of imaging optical simulation data of the projection apparatus of Figs. 1A and 1B. Referring to FIG. 3A, FIG. 3A is a modulation transfer function (MTF) whose horizontal axis is a focus shift and the vertical axis is a modulus of the optical transfer function (modulus of the). OTF). In Fig. 3A, a simulation data diagram of light having a wavelength of 430 nm to 680 nm is used. In Fig. 3B, the left and right are sequentially graphs of field curvature and distortion, and are simulated by light having a wavelength of 550 nm. Since the patterns shown in FIGS. 3A and 3B are all within the standard range, it can be verified that the projection apparatus 1000 of the present embodiment can achieve a good imaging effect.

Another embodiment of the projection lens 100 is exemplified below. It should be noted that the data sheets listed in Table 4 below are not intended to limit the present invention, and any one of ordinary skill in the art can make appropriate changes to their parameters or settings after referring to the present invention. However, it should still fall within the scope of the invention.

The definition of each parameter in Table 4 and the lens corresponding to each surface can be referred to the foregoing description, and will not be repeated here. In addition, the surface S17 and the surface S18 of the fourth table are aspherical, and the non-spherical formula can be referred to the foregoing, and will not be further described herein. The parameter values of surfaces S17 and S18 are listed below in Table 5.

The projection lenses described in Tables 4 and 5 also have similar functions and advantages as the projection lens 100 described in Tables 1, 2, and 3, and will not be repeated here.

In summary, in the projection apparatus and the projection lens according to an embodiment of the present invention, the first lens group of negative refracting power and the second lens group of positive refracting power can achieve the effect of zooming and generate F value (F-number) less than or equal to 2. Moreover, by arranging at least one aspherical mirror in the second lens group, the projection lens can have good imaging quality under the characteristics of a large aperture, thereby further providing the projection device with high brightness and excellent projection quality.

In addition, in an embodiment of the present invention, by disposing the aperture stop in the second lens group closer to the light valve, the light that is partially away from the optical axis can be filtered out, thereby further improving an embodiment of the present invention. The projection quality of the projection device.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents, and are not intended to limit the scope of the invention; and the first, second, ..., such as the first lens mentioned in this specification. The group and the second lens group are only used to indicate the names of the components, and are not intended to limit the upper or lower limits of the number of components.

50. . . Screen

100. . . Projection lens

110. . . First lens group

111. . . First lens

112. . . Second lens

113. . . Third lens

114. . . Fourth lens

120. . . Second lens group

121. . . Fifth lens

122. . . Sixth lens

123. . . Seventh lens

124. . . Eighth lens

125. . . Ninth lens

126. . . Tenth lens

210. . . Lighting unit

220. . . Light valve

230. . . Light protection cover

240. . . Aperture diaphragm

1000. . . Projection device

L1. . . Illumination beam

L2. . . Image beam

S1~S20. . . surface

D8, D20. . . Variable distance

X. . . Optical axis

1A and FIG. 1B are schematic diagrams showing optical structures of projection devices at different zoom magnifications according to an embodiment of the invention.

2A and 2B are schematic views showing the optical structure of the projection lens shown in Figs. 1A and 1B, respectively.

3A and 3B are diagrams of imaging optical simulation data of a projection lens in the projection apparatus of Figs. 1A and 1B.

50. . . Screen

100. . . Projection lens

110. . . First lens group

111. . . First lens

112. . . Second lens

113. . . Third lens

114. . . Fourth lens

120. . . Second lens group

121. . . Fifth lens

122. . . Sixth lens

123. . . Seventh lens

124. . . Eighth lens

125. . . Ninth lens

126. . . Tenth lens

210. . . Lighting unit

220. . . Light valve

230. . . Light protection cover

240. . . Aperture diaphragm

1000. . . Projection device

L1. . . Illumination beam

L2. . . Image beam

S1~S20. . . surface

D8, D20. . . distance

X. . . Optical axis

Claims (24)

A projection device comprising: an illumination unit for providing an illumination beam; a light valve disposed on the transmission path of the illumination beam for converting the illumination beam into an image beam; and a projection lens disposed on the illumination lens a projection beam of the image beam for projecting the image beam, the projection lens comprising: a first lens group having a negative refracting power, the first lens group including at least four lenses; and a second lens group disposed on Between the first lens group and the light valve, the second lens group has a positive refracting power, the second lens group includes at least six lenses and includes at least one aspheric lens, the first lens group and the second lens group Relatively moving for zooming, wherein the projection lens has an F value less than or equal to two. The projection device of claim 1, wherein the projection lens satisfies the following relationship: 0.53 < | f2 / f1 | < 0.69; 1.98 < | f1/fw | < 2.66; 1.36 < | f2 / fw | 1.42; wherein f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and fw is the effective focal length of the projection lens at a wide-angle end. The projection device of claim 1, wherein the first lens group sequentially includes: a first lens, from an image side to an object side; a second lens, a third lens and a fourth lens. The projection device of claim 3, wherein the diopter of the first lens, the second lens, the third lens, and the fourth lens are positive, negative, negative, and positive. The projection device of claim 4, wherein the first lens is a lenticular lens, the second lens is a convex-concave lens having a concave surface facing the object side, and the third lens is a double concave lens, and the third lens The four lens is a lenticular lens. The projection device of claim 1, wherein the second lens group sequentially includes: a fifth lens, a sixth lens, a seventh lens, and an eighth lens from an image side to an object side. a ninth lens and a tenth lens, wherein the aspherical lens may be the fifth lens, the sixth lens, the seventh lens, the eighth lens or the ninth lens. The projection device of claim 6, wherein the tenth lens has a negative refracting power. The projection device of claim 6, wherein the refracting power of the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are positive Positive, positive, negative, positive, and negative. The projection device of claim 6, wherein the fifth lens is a meniscus lens having a concave surface facing the object side, and the sixth lens is a concave-convex lens having a concave surface facing the object side, the seventh lens being a The lenticular lens is a double concave lens, and the ninth lens is a lenticular lens, and the tenth lens is a convex-concave lens with a concave surface facing the object side. The projection device of claim 6, wherein the seventh lens and the eighth lens form a cemented lens. The projection device of claim 6, further comprising an aperture stop disposed between the eighth lens and the ninth lens. The projection device of claim 1, wherein the first lens group is movable relative to the second lens group while the position of the second lens group is fixed. A projection lens comprising: a first lens group disposed between an image side and an object side, having a negative refracting power, comprising at least four lenses; and a second lens group disposed on the first lens group and the Between the object sides, the second lens group has a positive refracting power, the second lens group includes at least six lenses and includes at least one aspheric lens, and the first lens group and the second lens group are on the image side and the The object sides are relatively moved to perform zooming, wherein the projection lens has an F value less than or equal to two. The projection lens of claim 13, wherein the projection lens satisfies the following relationship: 0.53<| f2/f1 | <0.69; 1.98<| f1/fw |<2.66; 1.36<| f2/fw | 1.42; wherein f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and fw is the effective focal length of the projection lens at a wide-angle end. The projection lens of claim 13, wherein the first lens group sequentially includes from the image side to the object side: a first through a mirror, a second lens, a third lens, and a fourth lens. The projection lens of claim 15, wherein the diopter of the first lens, the second lens, the third lens, and the fourth lens are positive, negative, negative, and positive. The projection lens of claim 15, wherein the first lens is a lenticular lens, the second lens is a convex-concave lens having a concave surface facing the object side, and the third lens is a double concave lens, and the third lens The four lens is a lenticular lens. The projection lens of claim 13, wherein the second lens group sequentially includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens from the image side to the object side. a ninth lens and a tenth lens, wherein the aspherical lens may be the fifth lens, the sixth lens, the seventh lens, the eighth lens or the ninth lens. The projection lens of claim 18, wherein the tenth lens has a negative refracting power. The projection lens of claim 18, wherein the refracting power of the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are positive Positive, positive, negative, positive, and negative. The projection lens of claim 18, wherein the fifth lens is a meniscus lens having a concave surface facing the object side, and the sixth lens is a meniscus lens having a concave surface facing the object side, the seventh lens being a A lenticular lens, the eighth lens is a double concave lens, the ninth lens is a lenticular lens, and the tenth lens is a convex-concave lens with a concave surface facing the object side. The projection lens of claim 18, wherein the seventh lens and the eighth lens form a cemented lens. The projection lens of claim 13, further comprising an aperture stop disposed between the eighth lens and the ninth lens. The projection device of claim 13, wherein the first lens group is movable relative to the second lens group while the position of the second lens group is fixed.