JP2010217887A - Fixed-focus lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed-focus lens which is disposed between a primary image side and a secondary image side. <P>SOLUTION: The fixed-focus lens 100 includes a second lens group 110, a first lens group 130 and a curved reflecting mirror which are arranged in the order starting from a primary-image side to a secondary-image side. The second lens group includes a first lens 112, a second lens 114 and a third lens 116, arranged in the order starting from the primary-image side to the secondary-image side. The refractive power of the first lens and the third lens are both positive, and all the first, second and third lenses are spherical lenses. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens, and more particularly, to a fixed-focus lens.

  The fixed focus lens is one of optical elements often used in an optical system, and is widely applied to surveillance cameras, vehicle-mounted cameras, rear projection televisions, projectors, and the like. As photoelectric technology advances, high quality projectors have tended to increase in recent years. Among them, in order to shorten the projection distance from the projector to the screen and obtain a large size projection screen, a fixed focus lens having a relatively wide viewing angle is usually adopted in the projector. . However, employing such a lens may cause image difference problems such as distortion, field curvature, and astigmatism on the projection screen. Therefore, in order to improve the image difference problem of the projection screen, the conventional technology uses a plurality of aspherical lenses or employs means for increasing the number of lenses and the length of the lenses.

  In addition, in order to reduce the length of the lens and solve the image difference problem, there is a means for adding a reflecting mirror to the lens. For example, Patent Document 1 uses 16 lenses and one reflector to shorten the length of the lens and solves the problem of image difference. Patent Document 2 discloses 18 lenses and 2 lenses. This object is achieved by using a reflector. Further, by adopting a plurality of reflecting mirrors, the projection distance from the projector to the screen can be shortened. For example, refer to Patent Documents 3-7 and the like. However, as described above, the means for increasing the number of lenses and the means for adding a plurality of reflecting mirrors shorten the length of the lens and at the same time eliminate the image difference problem, making it difficult to manufacture and assemble the lens. Projector manufacturing costs will also increase.

US Pat. No. 7,009,765 US 2004/0233394 US Pat. No. 5,477,349 US Pat. No. 6,994,442 US Pat. No. 6,989,936 US Pat. No. 6,690,517 US Pat. No. 6,984,044

  An object of the present invention is to provide a fixed focus lens that has both low cost and excellent optical characteristics, can effectively eliminate an image difference, and can reduce the volume of a projection system.

  Other objects and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

  In order to achieve one or some or all of the above-mentioned objectives or other objectives, an embodiment of the present invention provides a fixed focus lens disposed between the main image side and the second image side. The fixed focus lens includes a first lens group, a second lens group, and a curved reflecting mirror. The first lens group is disposed between the main image side and the second image side, and includes a non-specular lens. The second lens group is disposed in the optical path between the main image side and the first lens group, and is arranged in order from the main image side to the second image side, the second lens, and the third lens. including. The refractive power of the first lens and the third lens is both positive, and the first lens, the second lens, and the third lens are spherical lenses. Therefore, the image light flux from the main image side and passed through the first lens group and the second lens group is one of a butterfly-like light spot and a trapezoid-like light spot on the reference plane. The reference plane is located between the first lens group and the curved reflecting mirror, and is perpendicular to the portion of the optical axis between the first lens group and the curved reflecting mirror. The image light beam forming the butterfly light spot is compensated after being reflected by the curved reflector to form a rectangular light spot, and the image light beam forming the trapezoidal light spot is compensated after being reflected by the curved reflector. To form another rectangular light spot.

  In order to achieve one or a part or all of the above-mentioned objectives or other objectives, an embodiment of the present invention is arranged between a main image side and a second image side and has a fixed focus having an optical axis. Provide a lens. A light valve is disposed on the main image side, and the light valve emits an image beam. The fixed focus lens includes a first lens group, a second lens group, and a curved reflecting mirror. The light valve is disposed between the main image side and the second image side and emits a video light beam. The first lens group is disposed between the main image side and the second image side, and includes an aspheric lens. The second lens group is disposed in the optical path between the main image side and the first lens group, and is arranged in order from the main image side to the second image side, the second lens, and the third lens. including. The refractive powers of the first lens and the third lens are both positive, and the first lens, the second lens, and the third lens are spherical lenses. Therefore, the image light flux that has passed through the first lens group and the second lens group forms one of the first-type light spot and the second-type light spot on the reference plane, and the reference plane is the first lens group. Between the first lens unit and the curved reflecting mirror, and perpendicular to the optical axis portion between the first lens group and the curved reflecting mirror. The image light beam that forms the first type light spot is reflected by the curved reflector to be compensated to form a rectangular light spot, and the image light beam that forms the second type light spot is reflected by the curved reflector. Is compensated to form another rectangular light spot.

  The first butterfly reference point a, second butterfly reference point b, third butterfly reference point c, fourth butterfly reference point d, fifth butterfly reference point e, Six butterfly reference point f, seventh butterfly reference point g, eighth butterfly reference point h, ninth butterfly reference point i, tenth butterfly reference point j, eleventh butterfly reference point k, tenth Including a butterfly reference point m and a thirteenth butterfly reference point n, the butterfly reference points are the first image point A, the second image point B, and the third image point C in the light valve, respectively. , Fourth video point D, fifth video point E, sixth video point F, seventh video point G, eighth video point H, ninth video point I, tenth video point J, eleventh video point K, The twelfth image point M and the thirteenth image point N correspond to the image point formed after receiving the imaging action of the first lens group and the second lens group, and the butterfly reference point and the image point described above. The relationship between is at least the following first condition and Satisfy one of the two conditions.

  The first condition is:

且つ、

and,

である。

It is.

  The second condition is

且つ、

and,

である。

It is.

  The second type light spot includes the first trapezoid reference point a ′, the second trapezoid reference point b ′, the third trapezoid reference point c ′, the fourth trapezoid reference point d ′, the fifth trapezoid reference point e ′, Including a trapezoidal reference point f ′, a seventh trapezoidal reference point g ′, an eighth trapezoidal reference point h ′, and a ninth trapezoidal reference point i ′. Point A, second video point B, third video point C, fourth video point D, fifth video point E, sixth video point F, seventh video point G, eighth video point H, and ninth video point I Corresponds to the image point formed after receiving the imaging action of the first lens group and the second lens group, and the aforementioned trapezoid reference point satisfies the following third condition.

  The third condition is

である。

It is.

In order to achieve one or some or all of the above-mentioned objectives or other objectives, an embodiment of the present invention provides a fixed focus lens disposed between the main image side and the second image side. The fixed focus lens includes a first lens group, a second lens group, and a curved reflecting mirror. The first lens group is disposed between the main image side and the second image side, and includes an aspheric lens. The second lens group is disposed in the optical path between the main image side and the first lens group, and is arranged in order from the main image side to the second image side, the second lens, and the third lens. including. The refractive powers of the first lens and the third lens are both positive, and each of the first lens, the second lens, and the third lens is a spherical lens. If the effective focal length of the fixed focal length lens is F, the effective focal length of the first lens group is F ₁ , and the effective focal length of the second lens group is F ₂ , the fixed focal length lens is 8.5 <| F ₁ /F|<50.1 and 20.2 <| F ₂ /F|<75.7 satisfy at least one condition.

  In one embodiment of the present invention, the reference plane passes through the midpoint position between the first lens group and the curved reflecting mirror.

  In an embodiment of the present invention, the fixed focus lens further includes a light valve, and the deviation amount of the light valve with respect to the optical axis is 100% (≧ 100%) or more.

  In one embodiment of the present invention, the image light flux that has passed through the first lens group and the second lens group has a distance from the light beam focal point of the image light flux close to the optical axis to the first lens group. It is smaller than the distance from the light beam focus to the first lens unit.

  In one embodiment of the present invention, the second lens group includes a fixed lens group and a movable lens group. The fixed lens group is kept stationary with respect to the fixed focus lens, and the movable lens group moves relative to the fixed lens group, thereby completing the focusing.

  In one embodiment of the present invention, the second lens group includes at least a low chromatic dispersion lens having an Abbe number greater than 75, and the refractive index of the low chromatic dispersion lens is less than 1.55.

  In one embodiment of the present invention, the second lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the main image side to the second image side. , Including a seventh lens and an eighth lens. The refractive power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are, in order, positive, negative, positive, negative, positive, negative, Positive and negative. Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are each a spherical lens, and the eighth lens is an aspheric lens. . In addition, the first lens, the third lens, the fifth lens, and the seventh lens are, for example, biconvex lenses, and the second lens and the eighth lens are concave and convex lenses having convex surfaces directed to the second image side, respectively. The fourth lens is a concavo-convex lens with a convex surface facing the main image side, and the sixth lens is a biconcave lens, of which the first lens and the second lens constitute a first adhesive lens, The lens and the sixth lens constitute a second adhesive lens.

  In one embodiment of the present invention, the second lens group includes a ninth lens. The refractive power of the ninth lens is negative. Among them, the ninth lens is an aspheric lens. The ninth lens is a concave-convex lens having a convex surface directed toward the second image side.

  In one embodiment of the present invention, the second lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the main image side to the second image side. , Seventh lens, eighth lens, ninth lens and tenth lens. The refractive powers of the first lens, the second lens, the third lens, the fourth lens, 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, positive, negative, positive, positive, negative. Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are each spherical lenses. The first lens and the ninth lens are, for example, concave and convex lenses whose convex surfaces are directed to the second image side, and the second lens, the sixth lens, and the eighth lens are biconvex lenses, respectively. Each of the lens and the fifth lens is a concavo-convex lens whose convex surface is directed to the main image side, the fourth lens is a concavo-convex lens whose convex surface is directed to the main image side, the seventh lens is a biconcave lens, and The tenth lens is a concavo-convex lens having a convex surface directed toward the second image side.

  In one embodiment of the present invention, the first lens group includes an eleventh lens and a twelfth lens arranged in order from the main image side to the second image side. The refractive powers of the eleventh lens and the twelfth lens are sequentially positive and negative. Among them, the eleventh lens and the twelfth lens are aspherical lenses, respectively. The eleventh lens is a concavo-convex lens whose convex surface is directed to the second image side, and the twelfth lens is a concavo-convex lens whose convex surface is directed to the second image side.

  In one embodiment of the present invention, the second lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the main image side to the second image side. , Seventh lens, eighth lens and ninth lens. The refractive powers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens are positive, positive, positive, negative, Positive, negative, positive, positive, negative. Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are spherical lenses, respectively. In addition, the first lens, the seventh lens, and the eighth lens are, for example, concave and convex lenses whose convex surfaces are directed to the second image side, and the second lens and the fifth lens are biconvex lenses, respectively. The lens is a concavo-convex lens whose convex surface faces the main image side, the fourth lens is a concavo-convex lens whose convex surface faces the main image side, the sixth lens is a biconcave lens, and the ninth lens is a convex surface Is a concave-convex lens toward the second image side.

  In one embodiment of the present invention, the first lens group includes a tenth lens and an eleventh lens arranged in order from the main image side to the second image side. The refractive powers of the tenth lens and the eleventh lens are positive and negative in order. Among them, the tenth lens and the eleventh lens are aspherical lenses, respectively. The tenth lens is a concavo-convex lens whose convex surface is directed to the second image side, and the eleventh lens is a concavo-convex lens whose convex surface is directed to the second image side.

  In one embodiment of the present invention, the second lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the main image side to the second image side. And a seventh lens. The refractive powers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are positive, negative, positive, negative, positive, negative, and positive in this order. Among them, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are spherical lenses, respectively. The first lens and the third lens are, for example, biconvex lenses, the second lens is a concave-convex lens having a convex surface facing the second image side, and the fourth lens and the sixth lens are respectively The convex lens is a concave / convex lens facing the main image side, the fifth lens is a concave / convex lens having the convex surface facing the main image side, and the seventh lens is a biconvex lens. Among them, the first lens and the second lens constitute a first adhesive lens, and the fourth lens and the fifth lens constitute a second adhesive lens.

  In one embodiment of the present invention, the first lens group includes an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in order from the main image side to the second image side. The refractive powers of the eighth lens, the ninth lens, the tenth lens, and the eleventh lens are negative, negative, negative, and negative in this order. Among them, the eighth lens, the ninth lens, and the tenth lens are each spherical lenses, and the eleventh lens is an aspheric lens. In addition, the eighth lens and the ninth lens are, for example, concave and convex lenses whose convex surfaces are directed toward the main image side, and the tenth lens and the eleventh lens are concave and convex portions whose convex surfaces are directed toward the second image side, respectively. It is a lens.

  In one embodiment of the present invention, the fixed focus lens further includes a reflective element, which is disposed in the light path between the first lens group and the second lens group. In one embodiment of the invention, the fixed focus lens further includes an aperture, which is disposed in the light path in the second lens group.

As described above, the fixed focus lens in the embodiment of the present invention eliminates the image difference by combining the curved reflector, the first lens group, and the second lens group, and also fixes the fixed focus by combining the entire lens group. The lens can have a relatively wide field of view (FOV). Of the fixed focus lenses, the three lenses closest to the main image side (that is, the first, second, and third lenses) are spherical lenses, and the first lens and the third lens, respectively. Both the refractive powers are positive, and this makes it possible to provide the fixed focus lens with good optical characteristics even when a small number of lenses and reflectors are used. Therefore, a projection apparatus that employs such a fixed focus lens can eliminate image differences, improve imaging quality, and reduce the volume of the projection system.
In order to clarify the above-described features and effects of the present invention, examples will be given below and described in detail with reference to the drawings.

It is a figure which shows the structure of the fixed focus lens in one Example of this invention. It is a figure which shows the structure of the fixed focus lens in the other Example of this invention. It is a figure which shows the image | video by the butterfly-shaped light spot in one Example of this invention. It is a figure which shows the relative position of the image point in a light valve. It is an imaging optical simulation data figure of the fixed focus lens in FIG. It is an imaging optical simulation data figure of the fixed focus lens in FIG. It is a figure which shows the structure of the fixed focus lens in the other Example of this invention. It is a figure which shows the image | video by the trapezoid light spot in one Example of this invention. It is a figure which shows the structure of the fixed focus lens in the other Example of this invention. It is a figure which shows the structure of the fixed focus lens in the other Example of this invention.

  The following description of each example illustrates a specific example in which the invention may be practiced with reference to the accompanying drawings. Directional terms mentioned in the present invention, for example, “up”, “down”, “front”, “back”, “left”, “right”, etc. are only for reference of the direction of the attached drawings. is there. Accordingly, the directional terminology used is used for purposes of explanation and is not intended to limit the invention.

  FIG. 1A is a diagram showing a structure of a fixed focus lens in one embodiment of the present invention. Reference is made to FIG. 1A. The fixed focus lens 100 in this embodiment is installed between the main image side and the second image side. The fixed focus lens 100 includes a first lens group 130, a second lens group 110, a curved reflecting mirror M, and a reflecting element 150. The curved reflector M is disposed in the optical path between the main image side and the second image side, and the refractive power of the curved reflector M is negative.

  The second lens group 110 is disposed in the light path between the main image side and the second image side. In this embodiment, the second lens group 110 includes a first lens 112, a second lens 114, a third lens 116, a fourth lens 118, a fifth lens 120, which are arranged in order from the main image side to the second image side. The first lens 112, the second lens 114, the third lens 116, the fourth lens 118, the fifth lens 120, the sixth lens 122, the sixth lens 122, the seventh lens 132, and the eighth lens 134. The refractive powers of the seventh lens 132 and the eighth lens 134 are sequentially positive, negative, positive, negative, positive, negative, positive, and negative. Among them, the first lens 112, the second lens 114, the third lens 116, the fourth lens 118, the fifth lens 120, the sixth lens 122, and the seventh lens 132 are each a spherical lens and an eighth lens. Reference numeral 134 denotes an aspheric lens. In other words, the three lenses closest to the main image side (in this embodiment, the first lens 112, the second lens 114, and the third lens 116) are both spherical lenses, and the first lens 112 and the third lens The refractive power of the lens 116 is both positive.

  In the present embodiment, the first lens 112, the third lens 116, the fifth lens 120, and the seventh lens 132 are biconvex lenses, and the second lens 114 and the eighth lens 134 have convex surfaces, respectively. The fourth lens 118 is a concave-convex lens whose convex surface is directed to the main image side, and the sixth lens 122 is a biconcave lens, of which the first lens 112 and the first lens 112 The two lenses 114 form a first adhesive lens 124, and the fifth lens 120 and the sixth lens 122 form a second adhesive lens 126.

  The first lens group 130 is disposed in the optical path between the second lens group 110 and the second image side. In the present embodiment, the first lens group 130 includes a ninth lens 136, and the refractive power of the ninth lens 136 is negative, of which the ninth lens 136 is an aspheric lens. In other words, the first lens group 130 includes at least an aspheric lens. The ninth lens 136 is a concave / convex lens having a convex surface directed toward the second image side.

  In order to ensure the quality of optical imaging, in the present embodiment, the fixed focus lens 100 satisfies at least one of the following two conditions.

(I) 8.5 <| F ₁ /F|<50.1
(Ii) 20.2 <| F ₂ /F|<75.7
Here, the effective focal length of the fixed-focus 100 is F, the effective focal length of the first lens group 130 is F _1, and the effective focal length of the second lens group 110 is F _2.

  In this embodiment, the image light flux that has passed through the first lens group 130 and the second lens group 110 has a distance from the light beam focal point of the image light flux close to the optical axis to the first lens group 130 that is far from the optical axis. It is smaller than the distance from the light beam focus to the first lens group 130.

  In the present embodiment, the reflecting element 150 is, for example, a plane mirror, and is disposed between the eighth lens 134 and the ninth lens 136, and is used to change the light path. The volume can be reduced.

  In the present embodiment, the first lens 112, the second lens 114, the third lens 116, the fourth lens 118, the fifth lens 120, and the sixth lens 122 are a movable lens group 127. The seventh lens 132 and the eighth lens 134 are a fixed lens group 129. Among them, the fixed lens group 129 is maintained so as not to move with respect to the fixed focus lens 100. When the fixed focus lens 100 has manufacturing tolerances, the movable lens group 127 in the second lens group 110 adjusts the relative position with respect to the fixed lens group 129, thereby effectively compensating for manufacturing tolerances and focusing. The effect of can be achieved.

  FIG. 1B is a diagram showing the structure of a fixed focus lens in another embodiment of the present invention. Refer to FIG. 1B. The fixed focus lens 100 ′ in this embodiment is similar to the fixed focus lens 100 shown in FIG. 1A, but the main difference between the two is that the fixed focus lens 100 ′ in this embodiment does not include the reflective element 150, and The position of the light valve 50 deviates from the optical axis A.

  In the present embodiment, the image light flux from the light valve 50 forms a butterfly-like light spot on the reference plane P1 after passing through the first lens group 130 and the second lens group 110. Among these, the reference plane P1 passes through the midpoint position between the first lens group 130 and the curved reflector M and is perpendicular to the optical axis A. The image by the butterfly light spot is compensated after being reflected by the curved reflector M to form a rectangular light spot. Therefore, the image by the butterfly light spot can be corrected so as to be an image having no distortion or a small degree of distortion, and is projected on a screen (not shown). At this time, if the height of the light valve 50 located on the main image side is C and the distance between the light valve 50 and the optical axis A is D, the light valve 50 of the fixed focus lens 100 ′ is The amount of deviation with respect to the optical axis A is defined as (C + D) / C. In the present embodiment, the deviation amount of the light valve is 100% or more (≧ 100%).

  Specifically, FIG. 1C is a diagram illustrating an image of a butterfly light spot according to an embodiment of the present invention. Referring to FIG. 1C, the image light flux that has passed through the first lens group 130 and the second lens group 110 forms a butterfly light spot as shown in FIG. 1C on the reference plane P1. The butterfly light spots are the first butterfly reference point a, the second butterfly reference point b, the third butterfly reference point c, the fourth butterfly reference point d, the fifth butterfly reference point e, and the sixth butterfly reference point. Reference point f, seventh butterfly reference point g, eighth butterfly reference point h, ninth butterfly reference point i, tenth butterfly reference point j, eleventh butterfly reference point k, and twelve butterfly Includes reference point m and thirteenth butterfly reference point n. The butterfly reference points mentioned above are the first image point A, the second image point B, the third image point C, the fourth image point D, the fifth image point E, and the fifth image point of the image formed on the light valve 50, respectively. Six image points F, seventh image point G, eighth image point H, ninth image point I, tenth image point J, eleventh image point K, twelve image point M, and thirteenth image point N This corresponds to an image point formed after receiving the imaging action of the first lens group 130 and the second lens group 110. FIG. 1D is a diagram showing the relative positions of the aforementioned video points in the light valve 50.

  In the present embodiment, the butterfly reference point and the image point described above satisfy at least one of the following first condition and second condition.

  The first condition is

且つ、

and,

である。

It is.

  The second condition is

且つ、

and,

である。

It is.

は、第一蝶形参考点ａと第三蝶形参考点ｃとの間の垂直距離であり、線分
（外２）

は、第二映像点Ｂと第五映像点Ｅとの間の垂直距離である。また、
（外３）

は、線分
（外４）

が線分
（外５）

とほぼ等しいことを示し、
（外６）

は、線分
（外７）

と線分
（外８）

とがほぼ等しいことを示す。また、第十蝶形参考点ｊ、第十一蝶形参考点ｋ、第十二蝶形参考点ｍ及び第十三蝶形参考点ｎは、それぞれ、光弁上の線分
（外９）

、線分
（外１０）

、線分
（外１１）

及び線分
（外１２）

の中点Ｊ、Ｋ、Ｍ及びＮに対応する。第十蝶形参考点ｊ、第十一蝶形参考点ｋ、第十二参考点ｍ及び第十三参考点ｎは、線分
（外１３）

、線分
（外１４）

、線分
（外１５）

及び線分
（外１６）

の中点ではない。 Note that the definition of each line segment described above is a vertical distance between each point, as shown in FIGS. 1C and 1D. For example, line segment (outside 1)

Is the vertical distance between the first butterfly reference point a and the third butterfly reference point c.

Is the vertical distance between the second video point B and the fifth video point E. Also,
(Outside 3)

Is a line segment (outside 4)

Is a line segment (outside 5)

Is almost equal to
(Outside 6)

Is a line segment (outside 7)

And line segment (outside 8)

And are almost equal. The tenth butterfly reference point j, the eleventh butterfly reference point k, the twelfth butterfly reference point m, and the thirteenth butterfly reference point n are each a line segment on the light valve (outside 9).

, Line segment (outside 10)

, Line segment (outside 11)

And line segment (outside 12)

Corresponds to the midpoints J, K, M, and N. The tenth butterfly reference point j, the eleventh butterfly reference point k, the twelfth reference point m, and the thirteenth reference point n are line segments (outside 13)

, Line segment (outside 14)

, Line segment (outside 15)

And line segment (outside 16)

It is not the middle point.

  As described above, in the fixed focal points 100 and 100 ′, the image difference of the optical imaging can be eliminated by the combination of the curved reflector M, the first lens group 130, and the second lens group 110. Further, in the fixed focus lenses 100 and 100 ′, the three lenses closest to the main image side (the first lens 112, the second lens 114, and the third lens 116) are each a spherical lens and the first lens. The refractive powers of the 112 and the third lens 116 are both positive, so that the fixed focus lenses 100 and 100 ′ have good optical characteristics even when a small number of lenses and reflectors are used. be able to. Further, when the fixed focus lenses 100 and 100 ′ include manufacturing tolerances, the manufacturing tolerance is effectively compensated by adjusting the relative position of the movable lens group 127 in the second lens group 110, and focusing adjustment is performed. The effect can be achieved. Therefore, the fixed focus lenses 100 and 100 'have advantages such as a wide field of view (viewing angle is about 156.67 °), a small image difference due to imaging, and a low degree of distortion. Furthermore, the fixed focus lenses 100 and 100 'use a small number of reflectors and lenses, so that the cost of the product is reduced, the problem that it is difficult to focus the optical axis of the optical system, and the difficulty of assembly is reduced. Can be lowered.

  The following content includes an example of the fixed focus lens 100. Note that the data listed in Tables 1 and 2 below are not intended to limit the present invention, and those skilled in the art will make appropriate changes to the parameters and settings after referring to the contents of the present invention. Although they can be made, those modifications are still within the scope of the invention.

表１において、間隔は、隣接する両表面が光軸Ａにおける直線距離を指し、例えば、表面Ｓ９の間隔は、表面Ｓ９から表面Ｓ１０までの光軸Ａにおいての直線距離である。備考欄の中の各レンズが対応する厚さ、屈折率及びアッベ数は、同じ列の中の各間隔、屈折率及びアッベ数が対応する数値を参照する。また、表１において、表面Ｓ１は、光弁５０の能動表面であり、表面Ｓ４、Ｓ５は、第二平板ガラス７０の両表面であり、且つ、表面Ｓ２、Ｓ３は、光弁５０を保護するための第一平板ガラス６０の両表面であり、そのうち、表面Ｓ１の列（ｒｏｗ）の中の間隔は、表面Ｓ２から光弁５０の能動表面までの間隔である。表面Ｓ６、Ｓ８は、第一接着レンズ１２４の両表面であり、表面Ｓ９、Ｓ１０は、第三レンズ１１６の両表面であり、表面Ｓ１１、Ｓ１２は、第四レンズ１１８の両表面であり、表面Ｓ１３、Ｓ１５は、第二接着レンズ１２６の両表面であり、表面Ｓ１６、Ｓ１７は、第七レンズ１３２の両表面であり、表面Ｓ１８、Ｓ１９は、第八レンズ１３４の両表面であり、表面Ｓ２０は、平面鏡１５０の反射面であり、表面Ｓ２１、Ｓ２２は、第九レンズ１３６の両表面であり、且つ、表面Ｓ２３は、曲面反射鏡Ｍの反射面である。

In Table 1, the interval indicates a linear distance between the two adjacent surfaces on the optical axis A. For example, the interval between the surfaces S9 is a linear distance on the optical axis A from the surface S9 to the surface S10. For the thickness, refractive index, and Abbe number to which each lens in the remarks column corresponds, refer to the numerical values to which the respective intervals, refractive index, and Abbe number in the same column correspond. In Table 1, the surface S1 is the active surface of the light valve 50, the surfaces S4 and S5 are both surfaces of the second flat glass 70, and the surfaces S2 and S3 protect the light valve 50. The distance in the row of the surface S1 is the distance from the surface S2 to the active surface of the light valve 50. The surfaces S6 and S8 are both surfaces of the first adhesive lens 124, the surfaces S9 and S10 are both surfaces of the third lens 116, and the surfaces S11 and S12 are both surfaces of the fourth lens 118. S13 and S15 are both surfaces of the second adhesive lens 126, surfaces S16 and S17 are both surfaces of the seventh lens 132, surfaces S18 and S19 are both surfaces of the eighth lens 134, and surface S20. Are the reflecting surfaces of the plane mirror 150, the surfaces S21 and S22 are both surfaces of the ninth lens 136, and the surface S23 is the reflecting surface of the curved reflecting mirror M.

  According to Table 1, the third lens 116 and the fifth lens 120 are lenses of low color dispersion material, the Abbe number is larger than 75, and the refractive index of the third lens 116 and the fifth lens 120 is Less than 1.55. In other words, the second lens group 110 includes at least a lens made of a low color dispersion material.

  In the present embodiment, the surfaces S21 to S23 rotate 90 degrees in the BDE mode in the direction opposite to the clockwise direction (BDE indicates the degree of rotation when the XZ plane rotates about the Y direction as the center of the axis. Show). In other words, under the action of the plane mirror 150, the light beam can be turned 90 degrees with respect to the original traveling direction after being reflected by the surface S20, thereby shortening the total length of the lens of the projection system. Can do.

  For parameters such as the radius of curvature and spacing of each surface, refer to Table 1, and a detailed description thereof will be omitted here.

  The aforementioned surfaces S18, S19, S21 to S23 are aspherical surfaces of even-order terms and can be expressed by the following equations.

ここで、Ｚは、光軸Ａ方向の偏移量（ｓａｇ）であり、ｃは、接触球（ｏｓｃｕｌａｔｉｎｇ ｓｐｈｅｒｅ）の半径の逆数であり、即ち、光軸Ａに近い所の曲率半径（例えば、表１の表面Ｓ１８、Ｓ１９、Ｓ２１〜Ｓ２３の曲率半径）の逆数である。ｋは、二次曲面係数（ｃｏｎｉｃ）であり、ｒは、非球面の高さであり、即ち、レンズ中心からレンズ辺縁への高さであり、Ａ_２、Ａ_４、Ａ_６、Ａ_８、Ａ_１０、Ａ_{１２・・・}は、非球面係数（ａｓｐｈｅｒｉｃ ｃｏｅｆｆｉｃｉｅｎｔ）であり、本実施例において、Ａ_２は、０である。表２にリストされているのは、表面Ｓ１８、Ｓ１９、Ｓ２１〜Ｓ２３のパラメータである。

Here, Z is a shift amount (sag) in the direction of the optical axis A, and c is a reciprocal of the radius of the contact sphere (ie, oscillating sphere), that is, a radius of curvature near the optical axis A (for example, It is the reciprocal of the curvature radii of the surfaces S18, S19, and S21 to S23 in Table 1. k is a quadric surface coefficient (conic), and r is the height of the aspheric surface, that is, the height from the lens center to the lens edge, and A ₂ , A ₄ , A ₆ , A _8. , A ₁₀ , A _12... Are aspheric coefficients, and A ₂ is 0 in this embodiment. Listed in Table 2 are the parameters for surfaces S18, S19, S21-S23.

図２Ａ及び図２Ｂは、図１の固定焦点レンズ１００の結像光学シミュレーションデータ図である。図２Ａと図２Ｂを参照する。図２Ａは、歪み（ｄｉｓｔｏｒｔｉｏｎ）のグラフであり、且つ、波長が５５０ｎｍである光に基づいてシミュレーションし得たものである。図２Ｂは、映像の横断光線扇形図（ｔｒａｎｓｖｅｒｓｅ ｒａｙ ｆａｎ ｐｌｏｔ）であり、且つ、波長が５５０ｎｍである光に基づいて作られたシミュレーションデータ図である。図２Ａと図２Ｂに示すグラフは、全て、標準の範囲内にあるので、本実施例の固定焦点レンズ１００は、広い視野角の場合でも、良好な結像品質を維持することができる。

2A and 2B are imaging optical simulation data diagrams of the fixed focus lens 100 of FIG. Please refer to FIG. 2A and FIG. 2B. FIG. 2A is a graph of distortion and can be simulated based on light having a wavelength of 550 nm. FIG. 2B is a transverse ray fan plot of an image, and is a simulation data diagram created based on light having a wavelength of 550 nm. Since the graphs shown in FIGS. 2A and 2B are all within the standard range, the fixed focus lens 100 of the present embodiment can maintain good imaging quality even when the viewing angle is wide.

  FIG. 3A is a diagram showing the structure of a fixed focus lens in another embodiment of the present invention. Refer to FIG. 3A. The fixed focus lens 300 of the present embodiment is disposed between the main image side and the second image side. The fixed focus lens 300 includes a first lens group 330, a second lens group 310, a curved reflecting mirror M, a reflecting element 350, and an aperture 360. The curved reflector M is disposed in the optical path between the main image side and the second image side, and the refractive power of the curved reflector M is negative.

  The second lens group 310 is disposed in the optical path between the main image side and the second image side. In the present embodiment, the second lens group 310 includes a first lens 312, a second lens 314, a third lens 316, a fourth lens 318, a fifth lens 320, which are arranged in order from the main image side to the second image side. Including a sixth lens 322, a seventh lens 324, an eighth lens 332, a ninth lens 334, and a tenth lens 336, and a first lens 312, a second lens 314, a third lens 316, a fourth lens 318, The refractive powers of the fifth lens 320, the sixth lens 322, the seventh lens 324, the eighth lens 332, the ninth lens 334, and the tenth lens 336 are positive, positive, positive, negative, positive, positive, negative, positive in this order. Positive and negative. Among them, the first lens 312, the second lens 314, the third lens 316, the fourth lens 318, the fifth lens 320, the sixth lens 322, the seventh lens 324, the eighth lens 332, the ninth lens 334, and the tenth lens. Reference numeral 336 denotes a spherical lens.

  In the present embodiment, the first lens 312 and the ninth lens 334 are concave and convex lenses whose convex surfaces are directed to the second image side, respectively, and the second lens 314, the sixth lens 322, and the eighth lens 332 are respectively The third lens 316 and the fifth lens 320 are concave / convex lenses whose convex surfaces are directed toward the main image side, and the fourth lens 318 is a concave / convex lens whose convex surfaces are directed toward the main image side. The seventh lens 324 is a biconcave lens, and the tenth lens 336 is a concave-convex lens having a convex surface directed toward the second image side.

  The first lens group 330 is disposed in the optical path between the second lens group 310 and the second image side. In the present embodiment, the second lens group 310 includes an eleventh lens 338 and a twelfth lens 340 arranged in order from the main image side to the second image side, and the eleventh lens 338 and the twelfth lens 340. The refractive power of the lens 340 is positive and negative in order. Among them, the eleventh lens 338 and the twelfth lens 340 are each an aspheric lens. In other words, the second lens group 310 includes at least an aspheric lens. The eleventh lens 338 is a concave / convex lens having a convex surface directed toward the second image side, and the twelfth lens 340 is a concave / convex lens having a convex surface directed toward the second image side.

  In order to ensure the quality of optical imaging, in the present embodiment, the fixed focus lens 300 satisfies at least one of the following two conditions.

(I) 8.5 <| F1 / F | <50.1
(Ii) 20.2 <| F2 / F | <75.7
Here, the effective focal length of the fixed focus lens 300 is F, the effective focal length of the first lens group 330 is F ₁ , and the effective focal length of the second lens group 310 is F ₂ . .

  In this embodiment, the image light flux that has passed through the first lens group 330 and the second lens group 310 has a distance from the light beam focal point of the image light flux close to the optical axis to the first lens group 330 that is far from the optical axis. It is smaller than the distance from the light beam focus to the first lens group 330.

  Further, in the present embodiment, the reflecting element 350 is, for example, a plane mirror, which is disposed between the tenth lens 336 and the eleventh lens 338 and is used to change the optical path, thereby projecting. The volume of the system can be reduced. The fixed focus lens 300 further includes an aperture 360, and the aperture 360 is disposed in the optical path of the second lens group 310.

  In this embodiment, the first lens 312, the second lens 314, the third lens 316, the fourth lens 318, the fifth lens 320, the sixth lens 322, and the seventh lens 324 are a movable lens group 327. . The eighth lens 332, the ninth lens 334, and the tenth lens 336 are a fixed lens group 329. Among them, the fixed lens group 329 is maintained so as not to move with respect to the fixed focus lens 300. When the fixed focus lens 300 includes manufacturing tolerances, the movable lens group 327 in the second lens group 310 adjusts the relative position with respect to the fixed lens group 329, thereby effectively compensating for manufacturing tolerances and focusing. The effect of can be achieved.

  Similarly, in this embodiment, the amount of deviation of the light valve with respect to the optical axis A is 100% or more (≧ 100%). The difference from the fixed focus lenses 100 and 100 ′ is that in this embodiment, the image light flux from the light valve 50 passes through the first lens group 330 and the second lens group 310, and then the trapezoidal light spot on the reference plane P 3. It is to form a video. Among them, the reference plane P3 passes through the midpoint position between the first lens group 330 and the curved reflecting mirror M and is perpendicular to the optical axis A. The image by the trapezoidal light spot is compensated after being reflected by the curved reflecting mirror M to form another rectangular light spot. Therefore, the image by the trapezoidal light spot is corrected so as to be an image having no distortion or a low degree of distortion, and is projected on a screen (not shown).

  Specifically, FIG. 3B is a diagram illustrating an image by a trapezoidal light spot in one embodiment of the present invention. Refer to FIG. 3B. The trapezoid light spots are the first trapezoid reference point a ′, the second trapezoid reference point b ′, the third trapezoid reference point c ′, the fourth trapezoid reference point d ′, the fifth trapezoid reference point e ′, and the sixth trapezoid reference point. f ', seventh trapezoid reference point g', eighth trapezoid reference point h 'and ninth trapezoid reference point i'. The aforementioned trapezoid reference points are the first image point A, the second image point B, the third image point C, the fourth image point D, the fifth image point E, and the sixth image of the image formed on the light valve 50, respectively. The image point F, the seventh image point G, the eighth image point H, and the ninth image point I correspond to image points formed after receiving the imaging action of the first lens group 330 and the second lens group 310. FIG. 1D is a diagram showing the relative positions of the above-described video points in the light valve 50.

  In the present embodiment, the aforementioned trapezoidal reference point satisfies the following third condition.

  The third condition is

且つ、

and,

である。

なお、前述の各線分の定義は、図３Ｂに示すように、それぞれ、各点間の垂直距離である。例えば、線分
（外１７）

は、第一台形参考点ａ′と第三台形参考点ｃ′との間の垂直距離である。

It is.

The definition of each line segment described above is a vertical distance between each point, as shown in FIG. 3B. For example, line segment (outside 17)

Is the vertical distance between the first trapezoid reference point a ′ and the third trapezoid reference point c ′.

  According to the above, in the fixed focus lens 300, the image difference of the optical imaging can be eliminated by the combination of the curved reflector M and the first lens group 330 and the second lens group 310. Of the fixed focus lens 300, the three lenses closest to the main image side are spherical lenses, and the refractive powers of the first lens 312 and the third lens 316 are both positive. Thus, even when a small number of lenses and reflecting mirrors are used for the fixed focus lens 300, it is possible to give good optical characteristics. Similarly, when the fixed focus lens 300 includes manufacturing tolerances, adjustment of the relative position of the movable lens group 327 can effectively compensate for manufacturing tolerances and achieve a focusing effect.

  The following content includes an example of a fixed focus 300. Note that the data listed in Tables 3 and 4 below does not limit the present invention, and those skilled in the art can make changes to the parameters or settings after referring to the present invention. However, those modifications still belong to the scope of the present invention.

表３において、間隔は、隣接する両表面が光軸Ａにおける直線距離を指し、例えば、表面Ｓ６の間隔は、表面Ｓ６から表面Ｓ７までの光軸Ａにおいての直線距離である。備考欄の中の各レンズが対応する厚さ、屈折率及びアッベ数は、同じ列の中の各間隔、屈折率及びアッベ数が対応する数値を参照する。また、表３において、表面Ｓ１は、光弁５０の能動表面であり、表面Ｓ４、Ｓ５は、第二平板ガラス７０の両表面であり、且つ、表面Ｓ２、Ｓ３は、光弁５０を保護するための第一平板ガラス６０の両表面であり、そのうち、表面Ｓ１の列（ｒｏｗ）の中に記入されている間隔は、表面Ｓ２から光弁５０までの間隔である。表面Ｓ６、Ｓ７は、第一レンズ３１２の両表面であり、表面Ｓ８、Ｓ９は、第二レンズ３１４の両表面であり、表面Ｓ１０、Ｓ１１は、第三レンズ３１６の両表面であり、表面Ｓ１２、Ｓ１３は、第四レンズ３１８の両表面であり、表面Ｓ１４、Ｓ１５は、第五レンズ３２０の両表面であり、表面Ｓ１６、Ｓ１７は、第六レンズ３２２の両表面であり、表面Ｓ１８、Ｓ１９は、第七レンズ３２４の両表面であり、表面Ｓ２０は、アパッチャー３６０であり、表面Ｓ２１、Ｓ２２は、第八レンズ３３２の両表面であり、表面Ｓ２３、Ｓ２４は、第九レンズ３３４の両表面であり、表面Ｓ２５、Ｓ２６は、第十レンズ３３６の両表面であり、表面Ｓ２７は、平面鏡３５０の反射面であり、表面Ｓ２８、Ｓ２９は、第十一レンズ３３８の両表面であり、表面Ｓ３０、Ｓ３１は、第十二レンズ３４０の両表面であり、且つ、表面Ｓ３２は、曲面反射鏡Ｍの反射面である。

In Table 3, the distance indicates a linear distance between the two adjacent surfaces on the optical axis A. For example, the distance between the surfaces S6 is a linear distance on the optical axis A from the surface S6 to the surface S7. For the thickness, refractive index, and Abbe number to which each lens in the remarks column corresponds, refer to the numerical values to which the respective intervals, refractive index, and Abbe number in the same column correspond. In Table 3, the surface S1 is the active surface of the light valve 50, the surfaces S4 and S5 are both surfaces of the second flat glass 70, and the surfaces S2 and S3 protect the light valve 50. The distance written in the row of the surface S1 is the distance from the surface S2 to the light valve 50. The surfaces S6 and S7 are both surfaces of the first lens 312, the surfaces S8 and S9 are both surfaces of the second lens 314, the surfaces S10 and S11 are both surfaces of the third lens 316, and the surface S12. , S13 are both surfaces of the fourth lens 318, the surfaces S14, S15 are both surfaces of the fifth lens 320, the surfaces S16, S17 are both surfaces of the sixth lens 322, and the surfaces S18, S19. Are both surfaces of the seventh lens 324, the surface S20 is an aperture 360, the surfaces S21 and S22 are both surfaces of the eighth lens 332, and the surfaces S23 and S24 are both surfaces of the ninth lens 334. The surfaces S25 and S26 are both surfaces of the tenth lens 336, the surface S27 is a reflecting surface of the plane mirror 350, and the surfaces S28 and S29 are both surfaces of the eleventh lens 338. , The surface S30, S31 are two surfaces of the twelfth lens 340, and the surface step S32, a reflecting surface of the curved reflecting mirror M.

  According to Table 3, the second lens 314, the third lens 316, the fifth lens 320, and the sixth lens 322 are lenses of low color dispersion material, the Abbe number is greater than 75, and the refractive index thereof. Is less than 1.55. In other words, the second lens group 310 includes at least a lens made of a low color dispersion material.

  The difference from the fixed focus lens 100 is that in this embodiment, the surfaces S28 to S32 of the fixed focus lens 300 are rotated 90 degrees clockwise in the ADE mode (ADE is the YZ plane). Indicates the degree of rotation when rotating around the X direction as the center of the axis). In other words, under the action of the plane mirror 350, the light beam can be turned 90 degrees with respect to the original traveling direction after being reflected by the surface S27, thereby shortening the total length of the lens of the projection system. Can do.

  For parameters such as the radius of curvature and spacing of each surface, refer to Table 3, and a detailed description thereof will be omitted here.

  The above-described surfaces S28 to S32 are even-order aspheric surfaces, and can be expressed by the following equations.

ここで、Ｚは、光軸Ａ方向の偏移量（ｓａｇ）であり、ｃは、接触球（ｏｓｃｕｌａｔｉｎｇ ｓｐｈｅｒｅ）の半径の逆数であり、即ち、光軸Ａに近い所の曲率半径（例えば、表３の表面Ｓ２８〜Ｓ３２の曲率半径）の逆数である。ｋは、二次曲面係数（ｃｏｎｉｃ）であり、ｒは、非球面の高さであり、即ち、レンズ中心からレンズ辺縁への高さであり、Ａ_２、Ａ_４、Ａ_６、Ａ_８、Ａ_１０、Ａ_{１２・・・}は、非球面係数（ａｓｐｈｅｒｉｃ ｃｏｅｆｆｉｃｉｅｎｔ）であり、本実施例において、Ａ_２は、０である。表４にリストされているのは、表面Ｓ２８〜Ｓ３２のパラメータである。

Here, Z is a shift amount (sag) in the direction of the optical axis A, and c is a reciprocal of the radius of the contact sphere (ie, oscillating sphere), that is, a radius of curvature near the optical axis A (for example, This is the reciprocal of the curvature radii of the surfaces S28 to S32 in Table 3. k is a quadric surface coefficient (conic), and r is the height of the aspheric surface, that is, the height from the lens center to the lens edge, and A ₂ , A ₄ , A ₆ , A _8. , A ₁₀ , A _12... Are aspheric coefficients, and A ₂ is 0 in this embodiment. Listed in Table 4 are the parameters for surfaces S28-S32.

図４は、本発明の他の実施例における固定焦点レンズの構造を示す図である。図４を参照する。本実施例における固定焦点レンズ４００は、主要イメージ側と第二イメージ側との間に配置される。固定焦点レンズ４００は、第一レンズ群４３０、第二レンズ群４１０、曲面反射鏡Ｍ、反射素子４５０及びアパッチャー４６０を含む。曲面反射鏡Ｍは、主要イメージ側と第二イメージ側との間の光経路に配置され、そのうち、曲面反射鏡Ｍの屈折力は、負である。

FIG. 4 is a diagram showing the structure of a fixed focus lens in another embodiment of the present invention. Please refer to FIG. The fixed focus lens 400 in this embodiment is disposed between the main image side and the second image side. The fixed focus lens 400 includes a first lens group 430, a second lens group 410, a curved reflecting mirror M, a reflecting element 450, and an aperture 460. The curved reflector M is disposed in the optical path between the main image side and the second image side, and the refractive power of the curved reflector M is negative.

  The second lens group 410 is disposed in the optical path between the main image side and the second image side. In this embodiment, the second lens group 410 includes a first lens 412, a second lens 414, a third lens 416, a fourth lens 418, a fifth lens 420, which are arranged in order from the main image side to the second image side. A sixth lens 422, a seventh lens 432, an eighth lens 434, and a ninth lens 436; and a first lens 412, a second lens 414, a third lens 416, a fourth lens 418, a fifth lens 420, The refractive powers of the sixth lens 422, the seventh lens 432, the eighth lens 434, and the ninth lens 436 are sequentially positive, positive, positive, negative, positive, negative, positive, positive, and negative. Among them, the first lens 412, the second lens 414, the third lens 416, the fourth lens 418, the fifth lens 420, the sixth lens 422, the seventh lens 432, the eighth lens 434, and the ninth lens 436 are respectively A spherical lens.

  The first lens 412, the seventh lens 432, and the eighth lens 434 are concave and convex lenses whose convex surfaces are directed to the second image side, and the second lens 414 and the fifth lens 420 are biconvex lenses, respectively. The third lens 416 is a concave / convex lens whose convex surface is directed toward the main image side, the fourth lens 418 is a concave / convex lens whose convex surface is directed toward the main image side, the sixth lens 422 is a biconcave lens, and The ninth lens 436 is a concave / convex lens having a convex surface directed toward the second image side.

  The first lens group 430 is disposed in the optical path between the second lens group 410 and the second image side. In the present embodiment, the first lens group 430 includes a tenth lens 438 and an eleventh lens 440 arranged in order from the main image side to the second image side, and the tenth lens 438 and the eleventh lens 440. The refractive powers of are positive and negative in order. Among them, the tenth lens 438 and the eleventh lens 440 are aspherical lenses, respectively. In other words, the first lens group 430 includes at least an aspheric lens. The tenth lens 438 is a concavo-convex lens whose convex surface is directed to the second image side, and the eleventh lens 440 is a concavo-convex lens whose convex surface is directed to the second image side.

  In order to ensure the quality of optical imaging, in the present embodiment, the fixed focus lens 400 satisfies at least one of the following two conditions.

(I) 8.5 <| F1 / F | <50.1
(Ii) 20.2 <| F2 / F | <75.7
Here, the effective focal length of the fixed focus lens 400 is F, the effective focal length of the first lens group 430 is F ₁ , and the effective focal length of the second lens group 410 is F ₂ . .

  In this embodiment, the image light flux that has passed through the first lens group 430 and the second lens group 410 has a distance from the light beam focal point of the image light flux close to the optical axis to the first lens group 430 that is far from the optical axis. It is smaller than the distance from the light beam focus to the first lens group 430.

  In the present embodiment, the reflecting element 450 is, for example, a plane mirror, which is disposed between the ninth lens 436 and the tenth lens 438, and is used to change the optical path, whereby the projection system The volume of can be reduced. The fixed focus lens 400 further includes an aperture 460, and the aperture 460 is disposed in the optical path of the second lens group 410.

  In this embodiment, the first lens 412, the second lens 414, the third lens 416, the fourth lens 418, the fifth lens 420, and the sixth lens 422 are a movable lens group 427. The seventh lens 432, the eighth lens 434, and the ninth lens 436 are a fixed lens group 429. Among them, the fixed lens group 429 is maintained so as not to move with respect to the fixed focus lens 400. When the fixed focus lens 400 includes manufacturing tolerances, the movable lens group 427 of the second lens group 410 adjusts the relative position with respect to the fixed lens group 429, thereby effectively compensating for manufacturing tolerance and focusing. The effect of can be achieved.

  Similarly, in this embodiment, the amount of deviation of the light valve with respect to the optical axis A is 100% or more (≧ 100%). Therefore, the image light flux from the light valve 50 can form a trapezoidal light spot on the reference plane P4 after passing through the first lens group 430 and the second lens group 410. Among them, the reference plane P4 passes through the midpoint position between the first lens group 430 and the curved reflector M and is perpendicular to the optical axis A. The image of the trapezoidal light spot is compensated after being reflected by the curved reflector M to form another rectangular light spot. Therefore, the image by the trapezoidal light spot can be corrected so as to be an image having no distortion or a small degree of distortion, and is projected on a screen (not shown). Then, in the fixed focus lens 400, the image difference in optical imaging can be eliminated by the combination of the curved reflector M and the first lens group 430 and the second lens group 410. Further, among the fixed focus lenses 400, the three lenses closest to the main image side are each spherical lenses, and the refractive powers of the first lens 412 and the third lens 416 are both positive. Furthermore, even when a small number of lenses and reflecting mirrors are used for the fixed focus lens 400, good optical characteristics can be provided. Similarly, when the fixed focus lens 400 includes a manufacturing tolerance, the manufacturing tolerance can be effectively compensated and the focusing effect can be achieved by adjusting the relative position of the movable lens group 427.

  The following content includes an example of a fixed focus lens 400. The data listed in Tables 5 and 6 below are not intended to limit the present invention, and those skilled in the art will make appropriate changes to the parameters and settings after referring to the contents of the present invention. Although they can be made, those modifications are still within the scope of the invention.

表５において、間隔は、隣接する両表面が光軸Ａにおける直線距離を指し、例えば、表面Ｓ６の間隔は、表面Ｓ６から表面Ｓ７までの光軸Ａにおいての直線距離である。備考欄の中の各レンズが対応する厚さ、屈折率及びアッベ数は、同じ列の中の各間隔、屈折率及びアッベ数が対応する数値を参照する。また、表５において、表面Ｓ１は、光弁５０の能動表面であり、表面Ｓ４、Ｓ５は、第二平板ガラス７０の両表面であり、且つ、表面Ｓ２、Ｓ３は、光弁５０を保護するための第一平板ガラス６０の両表面であり、そのうち、表面Ｓ１の列（ｒｏｗ）の中に記入されている間隔は、表面Ｓ２から光弁５０までの間隔である。表面Ｓ６、Ｓ７は、第一レンズ４１２の両表面であり、表面Ｓ８、Ｓ９は、第二レンズ４１４の両表面であり、表面Ｓ１０、Ｓ１１は、第三レンズ４１６の両表面であり、表面Ｓ１２、Ｓ１３は、第四レンズ４１８の両表面であり、表面Ｓ１４、Ｓ１５は、第五レンズ４２０の両表面であり、表面Ｓ１６、Ｓ１７は、第六レンズ４２２の両表面であり、表面Ｓ１８は、アッパチャー４６０であり、表面Ｓ１９、Ｓ２０は、第七レンズ４３２の両表面であり、表面Ｓ２１、Ｓ２２は、第八レンズ４３４の両表面であり、表面Ｓ２３、Ｓ２４は、第九レンズ４３６の両表面であり、表面Ｓ２５は、平面鏡４５０の反射面であり、表面Ｓ２６、Ｓ２７は、第十レンズ４３８の両表面であり、表面Ｓ２８、Ｓ２９は、第十一レンズ４４０の両表面であり、且つ、表面Ｓ３０は、曲面反射鏡Ｍの反射面である。

In Table 5, the distance indicates the linear distance between the adjacent surfaces on the optical axis A. For example, the distance between the surfaces S6 is the linear distance on the optical axis A from the surface S6 to the surface S7. For the thickness, refractive index, and Abbe number to which each lens in the remarks column corresponds, refer to the numerical values to which the respective intervals, refractive index, and Abbe number in the same column correspond. In Table 5, the surface S1 is the active surface of the light valve 50, the surfaces S4 and S5 are both surfaces of the second flat glass 70, and the surfaces S2 and S3 protect the light valve 50. The distance written in the row of the surface S1 is the distance from the surface S2 to the light valve 50. The surfaces S6 and S7 are both surfaces of the first lens 412, the surfaces S8 and S9 are both surfaces of the second lens 414, the surfaces S10 and S11 are both surfaces of the third lens 416, and the surface S12. , S13 are both surfaces of the fourth lens 418, the surfaces S14, S15 are both surfaces of the fifth lens 420, the surfaces S16, S17 are both surfaces of the sixth lens 422, and the surface S18 is It is an upper 460, the surfaces S19 and S20 are both surfaces of the seventh lens 432, the surfaces S21 and S22 are both surfaces of the eighth lens 434, and the surfaces S23 and S24 are both surfaces of the ninth lens 436. The surface S25 is a reflecting surface of the plane mirror 450, the surfaces S26 and S27 are both surfaces of the tenth lens 438, and the surfaces S28 and S29 are both surfaces of the eleventh lens 440. And, the surface S30 is the reflecting surface of the curved reflecting mirror M.

  According to Table 5, the second lens 414, the third lens 416, and the fifth lens 420 are lenses of low color dispersion material, the Abbe number is greater than 75, and the refractive index is 1.55. Smaller than. In other words, the second lens group 410 includes at least a lens made of a low color dispersion material.

  Similarly, in this embodiment, the surfaces S26 to S30 of the fixed focus lens 400 are rotated 90 degrees in the clockwise direction in the ADE mode (ADE is rotated about the X direction as the center of the YZ plane). Indicates the degree of rotation). In other words, under the action of the plane mirror 450, the light beam can be turned 90 degrees with respect to the original traveling direction after being reflected by the surface S25, thereby shortening the total length of the lens of the projection system. Can do.

  For parameters such as the radius of curvature and spacing of each surface, refer to Table 5, and the description thereof is omitted here.

  The aforementioned surfaces S26 to S30 are aspherical surfaces of even-order terms and can be expressed by the following formula.

ここで、Ｚは、光軸Ａ方向の偏移量（ｓａｇ）であり、ｃは、接触球（ｏｓｃｕｌａｔｉｎｇ ｓｐｈｅｒｅ）の半径の逆数であり、即ち、光軸Ａに近い所の曲率半径（例えば、表５の表面Ｓ２６〜Ｓ３０の曲率半径）の逆数である。ｋは、二次曲面係数（ｃｏｎｉｃ）であり、ｒは、非球面の高さであり、即ち、レンズ中心からレンズ辺縁への高さであり、Ａ_２、Ａ_４、Ａ_６、Ａ_８、Ａ_１０、Ａ_{１２・・・}は、非球面係数（ａｓｐｈｅｒｉｃ ｃｏｅｆｆｉｃｉｅｎｔ）であり、本実施例において、Ａ_２は、０である。表６にリストされているのは、表面Ｓ２６〜Ｓ３０のパラメータである。

Here, Z is a shift amount (sag) in the direction of the optical axis A, and c is a reciprocal of the radius of the contact sphere (ie, oscillating sphere), that is, a radius of curvature near the optical axis A (for example, It is the reciprocal of the curvature radii of the surfaces S26 to S30 in Table 5. k is a quadric surface coefficient (conic), and r is the height of the aspheric surface, that is, the height from the lens center to the lens edge, and A ₂ , A ₄ , A ₆ , A _8. , A ₁₀ , A _12... Are aspheric coefficients, and A ₂ is 0 in this embodiment. Listed in Table 6 are parameters for surfaces S26-S30.

図５は、本発明の他の実施例における固定焦点レンズの構造を示す図である。図５を参照する。本実施例における固定焦点レンズ５００は、主要イメージ側と第二イメージ側との間に配置される。固定焦点レンズ５００は、第一レンズ群５３０、第二レンズ群５１０、曲面反射鏡Ｍ及び反射素子５５０を含む。本実施例において、曲面反射鏡Ｍは、例えば、自由曲面反射鏡（ｆｒｅｅ ｆｏｒｍ ｒｅｆｌｅｃｔｉｖｅ ｍｉｒｒｏｒ）であり、それは、主要イメージ側と第二イメージ側との間の光径路に配置され、そのうち、曲面反射鏡Ｍの屈折力は、負である。

FIG. 5 is a diagram showing the structure of a fixed focus lens in another embodiment of the present invention. Please refer to FIG. The fixed focus lens 500 in this embodiment is disposed between the main image side and the second image side. The fixed focus lens 500 includes a first lens group 530, a second lens group 510, a curved reflecting mirror M, and a reflecting element 550. In the present embodiment, the curved reflecting mirror M is, for example, a free form reflecting mirror, which is disposed in the light path between the main image side and the second image side, of which curved reflecting The refractive power of the mirror M is negative.

  The second lens group 510 is disposed in the optical path between the main image side and the second image side. In this embodiment, the second lens group 510 includes a first lens 512, a second lens 514, a third lens 516, a fourth lens 518, a fifth lens 520, which are arranged in order from the main image side to the second image side. Refraction of the first lens 512, the second lens 514, the third lens 516, the fourth lens 518, the fifth lens 520, the sixth lens 532, and the seventh lens 534, including the sixth lens 532 and the seventh lens 534 The forces are, in order, positive, negative, positive, negative, positive, negative, positive. Among them, the first lens 512, the second lens 514, the third lens 516, the fourth lens 518, the fifth lens 520, the sixth lens 532, and the seventh lens 534 are each spherical lenses.

  In the present embodiment, each of the first lens 512 and the third lens 516 is a biconvex lens, and the second lens 514 is a concavo-convex lens having a convex surface directed toward the second image side, and the fourth lens 518 and the fourth lens 516. Each of the six lenses 532 is a concave / convex lens whose convex surface is directed toward the main image side, the fifth lens 520 is a concave / convex lens whose convex surface is directed toward the main image side, and the seventh lens 534 is a biconvex range. Of these, the first lens 512 and the second lens 514 form a first adhesive lens 522, and the fourth lens 518 and the fifth lens 520 form a second adhesive lens 524.

  The first lens group 530 is disposed in the optical path between the second lens group 510 and the second image side. In this embodiment, the second lens group 510 includes an eighth lens 536, a ninth lens 538, a tenth lens 540, and an eleventh lens 542 arranged in order from the main image side to the second image side, and The refractive powers of the eighth lens 536, the ninth lens 538, the tenth lens 540, and the eleventh lens 542 are negative, negative, negative, and negative in this order. Among them, the eighth lens 536, the ninth lens 538, and the tenth lens 540 are spherical lenses, respectively, and the eleventh lens 542 is an aspheric lens. The eighth lens 536 and the ninth lens 538 are concave and convex lenses having convex surfaces directed toward the main image side, respectively, and the tenth lens 540 and the eleventh lens 542 are respectively convex surfaces toward the second image side. It is a concave-convex lens heading.

  In order to ensure the quality of optical imaging, in the present embodiment, the fixed focus lens 500 satisfies at least one of the following two conditions.

(I) 8.5 <| F ₁ /F|<50.1
(Ii) 20.2 <| F ₂ /F|<75.7
Here, the effective focal length of the fixed focus lens 500 is F, the effective focal length of the first lens group 530 is F ₁ , and the effective focal length of the second lens group 510 is F ₂ . .

  In this embodiment, the image light flux that has passed through the first lens group 530 and the second lens group 510 has a distance from the light beam focal point of the image light flux close to the optical axis to the first lens group 530 that is far from the optical axis. It is smaller than the distance from the light beam focus to the first lens group 530.

  In the present embodiment, the reflecting element 550 is, for example, a plane mirror, which is disposed between the seventh lens 534 and the eighth lens 536, and is used to change the optical path, thereby projecting. The volume of the system can be reduced. The fixed focus lens 500 further includes an upper 560, and the upper 560 is disposed in the optical path of the second lens group 510.

  In this embodiment, the first lens 512, the second lens 514, the third lens 516, the fourth lens 518, and the fifth lens 520 are a movable lens group 527. The sixth lens 532 and the seventh lens 534 are a fixed lens group 529. Among them, the fixed lens group 529 is maintained so as not to move with respect to the fixed focus lens 500. When the fixed focus lens 500 has manufacturing tolerances, the movable lens group 527 of the second lens group 510 adjusts the relative position with respect to the fixed lens group 529, thereby effectively compensating for manufacturing tolerance and focusing. The effect of can be achieved.

  Similarly, in this embodiment, the amount of deviation of the light valve from the optical axis A is 100% or more (≧ 100%). Therefore, the image light flux from the light valve 50 can generate a trapezoidal light spot on the reference plane P5 after passing through the first lens group 530 and the second lens group 510. Among them, the reference plane P5 passes through the midpoint position between the first lens group 530 and the curved reflecting mirror M and is perpendicular to the optical axis A. The image by the trapezoidal light spot is compensated after being reflected by the curved reflecting mirror M to form another rectangular light spot. Therefore, the image by the trapezoidal light spot can be corrected so as to be an image having no distortion or a small degree of distortion, and is projected on a screen (not shown). Thus, in the fixed focus lens 500, the image difference in optical imaging can be eliminated by the combination of the curved reflector M and the lens groups 510 and 530. Of the fixed focus lens 500, the three lenses closest to the main image side are spherical lenses, and the refractive powers of the first lens 512 and the third lens 516 are both positive. Therefore, even when a small number of lenses and reflectors are used for the fixed focus 500, it is possible to still have good optical characteristics. Similarly, when the fixed focus lens 500 has manufacturing tolerances, the movable lens group 527 of the second lens group 510 adjusts the relative position with respect to the fixed lens group 529 to effectively compensate for the manufacturing tolerance. Can achieve the effect of focusing.

  The following content includes an example of the fixed focus lens 500. The data listed in Table 7 and Table 8 below do not limit the present invention, and those skilled in the art may make appropriate changes to the parameters or settings after referring to the present invention. Although possible, those modifications still fall within the scope of the invention.

表７において、間隔は、隣接する両表面が光軸Ａにおける直線距離を指し、例えば、表面Ｓ９の間隔は、表面Ｓ９から表面Ｓ１０までの光軸Ａにおいての直線距離である。備考欄の中の各レンズが対応する厚さ、屈折率及びアッベ数は、同じ列の中の各間隔、屈折率及びアッベ数が対応する数値を参照する。また、表７において、表面Ｓ１は、光弁５０の能動表面であり、表面Ｓ４、Ｓ５は、第二平板ガラス７０の両表面であり、且つ、表面Ｓ２、Ｓ３は、光弁５０を保護するための第一平板ガラス（ｃｏｖｅｒ ｇｌａｓｓ）６０の両表面であり、そのうち、表面Ｓ１の列（ｒｏｗ）の中に記入されている間隔は、表面Ｓ２から光弁５０までの間隔である。表面Ｓ６、Ｓ８は、第一接着レンズ５２２の両表面であり、表面Ｓ９、Ｓ１０は、第三レンズ５１６の両表面であり、表面Ｓ１１、Ｓ１３は、第二接着レンズ５２４の両表面であり、表面Ｓ１４は、アッパチャー５６０であり、表面Ｓ１５、Ｓ１６は、第六レンズ５３２の両表面であり、表面Ｓ１７、Ｓ１８は、第七レンズ５３４の両表面であり、表面Ｓ１９は、平面鏡５５０の反射面であり、表面Ｓ２０、Ｓ２１は、第八レンズ５３６の両表面であり、表面Ｓ２２、Ｓ２３は、第九レンズ５３８の両表面であり、表面Ｓ２４、Ｓ２５は、第十レンズ５４０の両表面であり、表面Ｓ２６、Ｓ２７は、第十一レンズ５４２の両表面であり、且つ、表面Ｓ２８は、曲面反射鏡Ｍの反射面である。

In Table 7, the distance indicates the linear distance between the adjacent surfaces on the optical axis A. For example, the distance between the surfaces S9 is the linear distance on the optical axis A from the surface S9 to the surface S10. For the thickness, refractive index, and Abbe number to which each lens in the remarks column corresponds, refer to the numerical values to which the respective intervals, refractive index, and Abbe number in the same column correspond. In Table 7, the surface S1 is the active surface of the light valve 50, the surfaces S4 and S5 are both surfaces of the second flat glass 70, and the surfaces S2 and S3 protect the light valve 50. The distance written in the row of the surface S1 is the distance from the surface S2 to the light valve 50. Surfaces S6 and S8 are both surfaces of the first adhesive lens 522, surfaces S9 and S10 are both surfaces of the third lens 516, and surfaces S11 and S13 are both surfaces of the second adhesive lens 524. The surface S14 is the upper 560, the surfaces S15 and S16 are both surfaces of the sixth lens 532, the surfaces S17 and S18 are both surfaces of the seventh lens 534, and the surface S19 is the reflecting surface of the plane mirror 550. The surfaces S20 and S21 are both surfaces of the eighth lens 536, the surfaces S22 and S23 are both surfaces of the ninth lens 538, and the surfaces S24 and S25 are both surfaces of the tenth lens 540. The surfaces S26 and S27 are both surfaces of the eleventh lens 542, and the surface S28 is a reflecting surface of the curved reflecting mirror M.

  According to Table 7, the first lens 512, the third lens 516, and the fifth lens 520 are lenses of low color dispersion material, the Appe number is greater than 75, and the refractive index is 1.55. Smaller than. In other words, the second lens group 510 includes at least a lens made of a low color dispersion material.

  Similarly, in the present embodiment, the surfaces S20 to S28 of the fixed focus lens 500 rotate 90 degrees in the clockwise direction in the ADE mode (when ADE rotates around the X direction as the axis). Indicates the degree of rotation). In other words, under the action of the plane mirror 550, the light beam can be turned 90 degrees with respect to the original traveling direction after being reflected by the surface S19, thereby shortening the total length of the lens of the projection system. Can do.

  For parameters such as the radius of curvature and spacing for each surface, refer to Table 1, and the description thereof is omitted here.

  The surfaces S26 and S27 described above are aspherical surfaces having odd-order terms, and can be expressed by the following equations.

ここで、Ｚは、光軸Ａ方向の偏移量（ｓａｇ）であり、ｃは、接触球（ｏｓｃｕｌａｔｉｎｇ ｓｐｈｅｒｅ）の半径の逆数であり、即ち、光軸Ａに近い所の曲率半径（例えば、表７の表面Ｓ２６、Ｓ２７の曲率半径）の逆数である。ｋは、二次曲面係数（ｃｏｎｉｃ）であり、ｒは、非球面の高さであり、即ち、レンズ中心からレンズ辺縁への高さであり、Ａ_１〜Ａ_１０は、非球面係数（ａｓｐｈｅｒｉｃ ｃｏｅｆｆｉｃｉｅｎｔ）である。表８にリストされているのは、表面Ｓ２６、Ｓ２７のパラメータである。

Here, Z is a shift amount (sag) in the direction of the optical axis A, and c is a reciprocal of the radius of the contact sphere (ie, oscillating sphere), that is, a radius of curvature near the optical axis A (for example, This is the reciprocal of the radii of curvature of the surfaces S26 and S27 in Table 7. k is a quadric surface coefficient (conic), r is the height of the aspheric surface, that is, the height from the lens center to the lens edge, and A _{1 to} A ₁₀ are the aspheric coefficient ( asphatic coefficent). Listed in Table 8 are the parameters for surfaces S26, S27.

また、前述の表面Ｓ２８は、自由曲面であり、次の式で表すことができる。

The surface S28 described above is a free-form surface and can be expressed by the following equation.

ここで、Ｚは、光軸Ａ方向の偏移量（ｓａｇ）であり、ｃは、接触球（ｏｓｃｕｌａｔｉｎｇ ｓｐｈｅｒｅ）の半径の逆数であり、即ち、光軸Ａに近い所の曲率半径（例えば、表７の表面Ｓ２８の曲率半径）の逆数である。ｋは、二次曲面係数（ｃｏｎｉｃ）であり、Ｘ、Ｙは、それぞれ、光軸Ａ方向に垂直する平面における点の座標値であり、且つ、Ｘ座標とＹ座標は、互いに垂直し、Ａ_１０、Ａ_２０、Ａ_０１、Ａ_{１１・・・}は、自由曲面係数（ａｓｐｈｅｒｉｃ ｃｏｅｆｆｉｃｉｅｎｔ）である。表９にリストされているのは、表面Ｓ２８のパラメータである。

Here, Z is a shift amount (sag) in the direction of the optical axis A, and c is a reciprocal of the radius of the contact sphere (ie, oscillating sphere), that is, a radius of curvature near the optical axis A (for example, This is the reciprocal of the radius of curvature of the surface S28 in Table 7. k is a quadric surface coefficient (conic), X and Y are coordinate values of points on a plane perpendicular to the direction of the optical axis A, respectively, and the X and Y coordinates are perpendicular to each other. ₁₀ , A ₂₀ , A ₀₁ , A _11... Are free-form surface coefficients. Listed in Table 9 are parameters for surface S28.

以上述べたところを総合すれば、本発明の実施例における固定焦点レンズは、曲面反射鏡と第一レンズ群及び第二レンズ群との組合せにより、像差を解消し、固定焦点レンズにより広い視野角を持たせることができる。また、固定焦点レンズは、数量が少ない反射鏡を使用することにより、製品のコストを抑え、光学システムの光軸のピント合わせが容易でないとの問題を無くし、組合せの困難度を下げることができる。また、固定焦点レンズのうち主要イメージ側に最も近い三つのレンズは、それぞれ、球面レンズであり、且つ、第一レンズ及び第三レンズの屈折力は、共に正であることにより、さらに、固定焦点レンズに、数量が少ないレンズ及び反射鏡を使用する場合でも、良好な光学特性を持たせることができる。よって、固定焦点レンズが投影装置に応用される場合は、このような構造により、投影システムの体積を有効に縮小し、結像の品質を向上することができる。また、本実施例のレンズの設計は、レンズの光通過量を増やし、且つ、スクリーンにおけるライトスポットの外へ広がる暈を大きくしないことができるので、画面の品質を向上することができる。さらに、第一レンズ群の相対位置を調整することにより、製造公差を有効に補償し、焦点合わせの効果を達成することができる。

In summary, the fixed focus lens in the embodiment of the present invention eliminates the image difference by combining the curved reflector, the first lens group, and the second lens group, and has a wider field of view by the fixed focus lens. Can have horns. In addition, the fixed focus lens can reduce the difficulty of the combination by reducing the cost of the product, eliminating the problem that it is not easy to focus the optical axis of the optical system, by using a small number of reflectors. . Further, among the fixed focus lenses, the three lenses closest to the main image side are spherical lenses, respectively, and the refractive powers of the first lens and the third lens are both positive. Even when a small number of lenses and reflecting mirrors are used for the lens, good optical characteristics can be provided. Therefore, when a fixed focus lens is applied to the projection apparatus, such a structure can effectively reduce the volume of the projection system and improve the imaging quality. In addition, the lens design of the present embodiment can increase the amount of light passing through the lens and not increase the wrinkles spreading out of the light spot on the screen, so that the quality of the screen can be improved. Furthermore, by adjusting the relative position of the first lens group, it is possible to effectively compensate for manufacturing tolerances and achieve a focusing effect.

  Although the present invention has been disclosed above based on the preferred embodiments described above, the preferred embodiments described above are not intended to limit the present invention, and those skilled in the art will understand the spirit of the present invention. As long as the scope of the present invention is not deviated, minor modifications and color changes can be made to the present invention. Therefore, the protection scope of the present invention is based on what is defined in the appended claims. In addition, any embodiment or claim of the present invention need not achieve all of the objects, advantages or features disclosed in the present invention. Further, the abstract part and the title of the invention are only for assisting the search of documents, and do not limit the scope of rights of the present invention.

50 Light valve 60 First flat glass 70 Second flat glass 100, 100 ', 300, 400, 500 Fixed focus lens 130, 330, 430, 530 First lens group 110, 310, 410, 510 Second lens group 127, 327, 427, 527 Movable lens group 129, 329, 429, 529 Fixed lens group 112, 312, 412, 512 First lens 114, 314, 414, 514 Second lens 116, 316, 416, 516 Third Lens 118, 318, 418, 518 Fourth lens 120, 320, 420, 520 Fifth lens 122, 322, 422, 532 Sixth lens 132, 324, 432, 534 Seventh lens 134, 332, 434, 536 Eighth Lens 136, 334, 436, 538 Ninth lens 336, 43 8, 540 Tenth lens 338, 440, 542 Eleventh lens 340 Twelfth lens 124, 522 First adhesive lens 126, 524 Second adhesive lens 360, 460, 560 Aperture 150, 350, 450, 550 Reflective element A Optical axis M Curved reflector P1, P3, P4, P5 Reference plane C Image height D Distance between image and optical axis A S1 to S32 Surface a to n Butterfly reference points a 'to n' Trapezoid reference points A to N images point

Claims (50)

A fixed focus lens disposed between the main image side and the second image side and having an optical axis,
The fixed focus lens is
A first lens group disposed between the main image side and the second image side and including an aspheric lens;
A second lens including a first lens, a second lens, and a third lens arranged in an optical path between the main image side and the first lens group and arranged in order from the main image side to the second image side; The second lens, which is a lens group, wherein the refractive power of the first lens and the third lens are both positive, and the first lens, the second lens, and the third lens are spherical lenses, respectively. Group,
A curved reflector disposed in an optical path between the main image side and the second image side, the refractive power of the curved reflector is negative, and a curved reflector,
Including
The image light flux that has passed from the main image side and passed through the first lens group and the second lens group forms one of a butterfly light spot and a trapezoidal light spot on a reference plane, and the reference plane has the first plane. Located between one lens group and the curved reflector, and perpendicular to a part of the optical axis between the first lens group and the curved reflector,
The image light beam forming the butterfly light spot is compensated after being reflected by the curved reflector to form a rectangular light spot, and the image light beam forming the trapezoid light spot is reflected by the curved reflector. Is compensated to form another rectangular light spot,
Fixed focus lens. The reference plane passes through a midpoint position between the first lens group and the curved reflector.
The fixed focus lens according to claim 1. In addition, including a light valve,
The amount of deviation of the light valve from the optical axis is 100% or more.
The fixed focus lens according to claim 1. The image light beam passes through the first lens group and the second lens group, and the distance from the light beam focal point of the image light beam close to the optical axis to the first lens group is far from the optical axis. Smaller than the distance from the light beam focus to the first lens group,
The fixed focus lens according to claim 1. The second lens group includes a fixed lens group and a movable lens group,
The fixed lens group is kept stationary relative to the fixed focus lens, and the movable lens group moves relative to the fixed lens group to complete focusing;
The fixed focus lens according to claim 1. The second lens group includes at least a low chromatic dispersion lens having an Abbe number greater than 75, and the refractive index of the low chromatic dispersion lens is less than 1.55.
The fixed focus lens according to claim 1. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the first lens arranged in order from the main image side to the second image side. Including 7th lens and 8th lens,
The refractive power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are positive, negative, Positive, negative, positive, negative, positive, negative,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are each spherical lenses, and the eighth lens is non- A spherical lens,
The fixed focus lens according to claim 1. The first lens, the third lens, the fifth lens and the seventh lens are biconvex lenses, respectively.
Each of the second lens and the eighth lens is a concavo-convex lens having a convex surface directed toward the second image side,
The fourth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The sixth lens is a biconcave lens;
The first lens and the second lens constitute a first adhesive lens,
The fifth lens and the sixth lens constitute a second adhesive lens;
The fixed focus lens according to claim 7. The first lens group includes a ninth lens, the refractive power of the ninth lens is negative, and the ninth lens is an aspheric lens.
The fixed focus lens according to claim 1. The ninth lens is a concavo-convex lens having a convex surface directed toward the second image side.
The fixed focus lens according to claim 9. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the first lens arranged in order from the main image side to the second image side. Including seven lenses, eighth lenses, ninth lenses and tenth lenses,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens. The refractive power is, in order, positive, positive, positive, negative, positive, positive, negative, positive, positive, negative,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are , Each is a spherical lens,
The fixed focus lens according to claim 1. The first lens and the ninth lens are concave / convex lenses each having a convex surface directed toward the second image side,
Each of the second lens, the sixth lens, and the eighth lens is a biconvex lens,
Each of the third lens and the fifth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The fourth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The seventh lens is a biconcave lens;
The tenth lens is a concavo-convex lens having a convex surface directed toward the second image side.
The fixed focus lens according to claim 11. The first lens group includes an eleventh lens and a twelfth lens arranged in order from the main image side to the second image side, and the refractive power of the eleventh lens and the twelfth lens is In order, positive and negative, each of the eleventh lens and the twelfth lens is an aspheric lens,
The fixed focus lens according to claim 1. The eleventh lens is a concavo-convex lens with a convex surface facing the second image side, and the twelfth lens is a concavo-convex lens with a convex surface facing the second image side.
The fixed focus lens according to claim 13. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the first lens arranged in order from the main image side to the second image side. Including 7th lens, 8th lens and 9th lens,
The refractive power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are in order. , Positive, positive, positive, negative, positive, negative, positive, positive, negative,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are spherical lenses, respectively. Is,
The fixed focus lens according to claim 1. The first lens, the seventh lens, and the eighth lens are concavo-convex lenses each having a convex surface directed toward the second image side,
Each of the second lens and the fifth lens is a biconvex lens,
The third lens is a concavo-convex lens having a convex surface directed toward the main image side,
The fourth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The sixth lens is a biconcave lens;
The ninth lens is a concavo-convex lens having a convex surface directed toward the second image side.
The fixed focus lens according to claim 15. The first lens group includes a tenth lens and an eleventh lens arranged in order from the main image side to the second image side, and the refractive powers of the tenth lens and the eleventh lens are in order, Positive and negative, and each of the tenth lens and the eleventh lens is an aspheric lens,
The fixed focus lens according to claim 1. The tenth lens is a concavo-convex lens whose convex surface is directed to the second image side, and the eleventh lens is a concavo-convex lens whose convex surface is directed to the second image side.
The fixed focus lens according to claim 17. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the first lens arranged in order from the main image side to the second image side. Including seven lenses,
The refractive powers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are positive, negative, positive, negative, positive in order. Negative, positive,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are each spherical lenses.
The fixed focus lens according to claim 1. Each of the first lens and the third lens is a biconvex lens,
The second lens is a concavo-convex lens having a convex surface directed toward the second image side,
Each of the fourth lens and the sixth lens is a concave-convex lens having a convex surface directed toward the main image side,
The fifth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The seventh lens is a biconvex lens;
The first lens and the second lens constitute a first adhesive lens,
The fourth lens and the fifth lens constitute a second adhesive lens;
The fixed focus lens according to claim 19. The first lens group includes an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in order from the main image side to the second image side,
The refractive powers of the eighth lens, the ninth lens, the tenth lens, and the eleventh lens are negative, negative, negative, negative in order,
The eighth lens, the ninth lens, and the tenth lens are each a spherical lens, and the eleventh lens is an aspheric lens.
The fixed focus lens according to claim 1. Each of the eighth lens and the ninth lens is a concave-convex lens with a convex surface facing the main image side,
Each of the tenth lens and the eleventh lens is a concavo-convex convex surface toward the second image side,
The fixed focus lens according to claim 21. Furthermore, including a reflective element disposed in the optical path between the first lens group and the second lens group,
The fixed focus lens according to claim 1. Furthermore, including an aperture disposed in the optical path in the second lens group,
The fixed focus lens according to claim 1. A fixed focus lens disposed between a main image side and a second image side and having an optical axis, a light valve disposed on the main image side, wherein the light valve emits an image beam; ,
The fixed focus lens is
A first lens group disposed between the main image side and the second image side and including an aspheric lens;
A second lens including a first lens, a second lens, and a third lens arranged in an optical path between the main image side and the first lens group and arranged in order from the main image side to the second image side; The second lens, which is a lens group, wherein the refractive power of the first lens and the third lens are both positive, and the first lens, the second lens, and the third lens are spherical lenses, respectively. Group,
A curved reflector disposed in an optical path between the main image side and the second image side, the refractive power of the curved reflector is negative, and a curved reflector,
Including
The image light flux that has passed through the first lens group and the second lens group forms one of a first type light spot and a second type light spot on a reference plane, and the reference plane is the first lens. A group located between the curved reflecting mirror and perpendicular to a part of the optical axis between the first lens group and the curved reflecting mirror;
The image light beam forming the first type light spot is compensated after being reflected by the curved reflector to form a rectangular light spot, and the image light beam forming the second type light spot is reflected by the curved surface reflection. Compensated after being reflected by the mirror to form another rectangular light spot,
The first light spot includes the first butterfly reference point, the second butterfly reference point, the third butterfly reference point, the fourth butterfly reference point, the fifth butterfly reference point, the sixth butterfly reference point, 7th butterfly shape reference point, 8th butterfly shape reference point, 9th butterfly shape reference point, 10th butterfly shape reference point, 11th butterfly shape reference point, 12th butterfly shape reference point and 13th butterfly shape reference point Including points,
The plurality of butterfly reference points are a first image point, a second image point, a third image point, a fourth image point, a fifth image point, a sixth image point, and a seventh image point, respectively, in the light valve. The eighth image point, the ninth image point, the tenth image point, the eleventh image point, the twelfth image point, and the thirteenth image point are subjected to the imaging action of the first lens group and the second lens group. Is a video point formed after
The relationship between the plurality of butterfly reference points and the plurality of video points satisfies at least one of the following first condition and second condition:
The first condition is

and,

And
The second condition is

and,

And
The second type light spot is the first trapezoid reference point, the second trapezoid reference point, the third trapezoid reference point, the fourth trapezoid reference point, the fifth trapezoid reference point, the sixth trapezoid reference point, the seventh trapezoid reference point, Including the eighth trapezoid reference point and the ninth trapezoid reference point,
The plurality of trapezoidal reference points are the first video point, the second video point, the third video point, the fourth video point, the fifth video point, the sixth video point, respectively, in the light valve. The seventh image point, the eighth image point, and the ninth image point are image points formed after receiving the imaging action of the first lens group and the second lens group;
The plurality of trapezoidal reference points satisfy the following third condition:
The third condition is

and,

Is,
Fixed focus lens. The reference plane passes through a midpoint position between the first lens group and the curved reflector.
The fixed focus lens according to claim 25. In addition, including a light valve,
The amount of deviation of the light valve from the optical axis is 100% or more.
The fixed focus lens according to claim 25. A fixed focus lens disposed between the main image side and the second image side and having an optical axis,
The fixed focus lens is
A first lens group disposed between the main image side and the second image side and including an aspheric lens;
A second lens including a first lens, a second lens, and a third lens arranged in an optical path between the main image side and the first lens group and arranged in order from the main image side to the second image side; The second lens, which is a lens group, wherein the refractive power of the first lens and the third lens are both positive, and the first lens, the second lens, and the third lens are spherical lenses, respectively. Group,
A curved reflector disposed in an optical path between the main image side and the second image side, the refractive power of the curved reflector is negative, and a curved reflector,
Including
The effective focal length of the fixed focal length lens is F, the effective focal length of the first lens group is F ₁ , the effective focal length of the second lens group is F ₂ , and the fixed focal length lens is 8 Satisfying at least one of the following conditions: 5 <| F ₁ /F|<50.1 and 20.2 <| F ₂ /F|<75.7
Fixed focus lens. In addition, including a light valve,
The amount of deviation of the light valve from the optical axis is 100% or more.
The fixed focus lens according to claim 28. The image light beam passes through the first lens group and the second lens group, and the distance from the light beam focal point of the image light beam close to the optical axis to the first lens group is far from the optical axis. Smaller than the distance from the light beam focus to the first lens group,
The fixed focus lens according to claim 28. The second lens group includes a fixed lens group and a movable lens group,
The fixed lens group is kept stationary relative to the fixed focus lens, and the movable lens group moves relative to the fixed lens group to complete focusing;
The fixed focus lens according to claim 28. The second lens group includes at least a low chromatic dispersion lens having an Abbe number greater than 75, and the refractive index of the low chromatic dispersion lens is less than 1.55.
The fixed focus lens according to claim 28. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the first lens arranged in order from the main image side to the second image side. Including 7th lens and 8th lens,
The refractive power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are positive, negative, Positive, negative, positive, negative, positive, negative,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are each spherical lenses, and the eighth lens is non- A spherical lens,
The fixed focus lens according to claim 28. The first lens, the third lens, the fifth lens and the seventh lens are biconvex lenses, respectively.
Each of the second lens and the eighth lens is a concavo-convex lens having a convex surface directed toward the second image side,
The fourth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The sixth lens is a biconcave lens;
The first lens and the second lens constitute a first adhesive lens,
The fifth lens and the sixth lens constitute a second adhesive lens;
The fixed focus lens according to claim 33. The first lens group includes a ninth lens, the refractive power of the ninth lens is negative, and the ninth lens is an aspheric lens.
The fixed focus lens according to claim 28. The ninth lens is a concavo-convex lens having a convex surface directed toward the second image side.
36. A fixed focus lens according to claim 35. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the first lens arranged in order from the main image side to the second image side. Including seven lenses, eighth lenses, ninth lenses and tenth lenses,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens. The refractive power is, in order, positive, positive, positive, negative, positive, positive, negative, positive, positive, negative,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are , Each is a spherical lens,
The fixed focus lens according to claim 28. The first lens and the ninth lens are concave / convex lenses each having a convex surface directed toward the second image side,
Each of the second lens, the sixth lens, and the eighth lens is a biconvex lens,
Each of the third lens and the fifth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The fourth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The seventh lens is a biconcave lens;
The tenth lens is a concavo-convex lens having a convex surface directed toward the second image side.
The fixed focus lens according to claim 37. The first lens group includes an eleventh lens and a twelfth lens arranged in order from the main image side to the second image side, and the refractive power of the eleventh lens and the twelfth lens is In order, positive and negative, each of the eleventh lens and the twelfth lens is an aspheric lens,
The fixed focus lens according to claim 28. The eleventh lens is a concavo-convex lens with a convex surface facing the second image side, and the twelfth lens is a concavo-convex lens with a convex surface facing the second image side.
40. A fixed focus lens according to claim 39. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the first lens arranged in order from the main image side to the second image side. Including 7th lens, 8th lens and 9th lens,
The refractive power of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are in order, Positive, positive, positive, negative, positive, negative, positive, positive, negative,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are spherical lenses, respectively. Is,
The fixed focus lens according to claim 28. The first lens, the seventh lens, and the eighth lens are concavo-convex lenses each having a convex surface directed toward the second image side,
Each of the second lens and the fifth lens is a biconvex lens,
The third lens is a concavo-convex lens having a convex surface directed toward the main image side,
The fourth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The sixth lens is a biconcave lens;
The ninth lens is a concavo-convex lens having a convex surface directed toward the second image side.
42. A fixed focus lens according to claim 41. The first lens group includes a tenth lens and an eleventh lens arranged in order from the main image side to the second image side, and the refractive powers of the tenth lens and the eleventh lens are in order, Positive and negative, and the tenth lens and the eleventh lens are aspherical lenses,
The fixed focus lens according to claim 28. The tenth lens is a concavo-convex lens whose convex surface is directed to the second image side, and the eleventh lens is a concavo-convex lens whose convex surface is directed to the second image side.
44. A fixed focus lens according to claim 43. The second lens group includes the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the first lens arranged in order from the main image side to the second image side. Including seven lenses,
The refractive powers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are positive, negative, positive, negative, positive in order. Negative, positive,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are each spherical lenses.
The fixed focus lens according to claim 28. Each of the first lens and the third lens is a biconvex lens,
The second lens is a concavo-convex lens having a convex surface directed toward the second image side,
Each of the fourth lens and the sixth lens is a concave-convex lens having a convex surface directed toward the main image side,
The fifth lens is a concavo-convex lens having a convex surface directed toward the main image side,
The seventh lens is a biconvex lens;
The first lens and the second lens constitute a first adhesive lens,
The fourth lens and the fifth lens constitute a second adhesive lens;
The fixed focus lens according to claim 45. The first lens group includes an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in order from the main image side to the second image side,
The refractive powers of the eighth lens, the ninth lens, the tenth lens, and the eleventh lens are negative, negative, negative, negative in order,
The eighth lens, the ninth lens, and the tenth lens are each a spherical lens, and the eleventh lens is an aspheric lens.
The fixed focus lens according to claim 28. Each of the eighth lens and the ninth lens is a concave-convex lens with a convex surface facing the main image side,
Each of the tenth lens and the eleventh lens is a concavo-convex convex surface toward the second image side,
48. A fixed focus lens according to claim 47. Furthermore, including a reflective element disposed in the optical path between the first lens group and the second lens group,
The fixed focus lens according to claim 28. Furthermore, including an aperture disposed in the optical path in the second lens group,
The fixed focus lens according to claim 28.

Images