CN109975949B - Projection lens and projection system - Google Patents
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Abstract
The invention discloses a projection lens and a projection system, comprising: the optical path steering component is positioned between the first optical system and the second optical system; the first optical system is used for imaging the incident beam to form a first image; an optical path turning component for reflecting the first image of the first optical system into the second optical system; the second optical system is used for carrying out secondary imaging on the first imaging to form second imaging; the main optical axis of the first optical system and the main optical axis of the second optical system form a set included angle. Adopt the light path to turn to the subassembly and reflect the formation of image of first optical system to the second optical system in to make the primary optical axis of first optical system and the primary optical axis of second optical system be the contained angle of setting for, adopt the mode of reflection light path to make projection lens's optical axis turn over from this, reduce projection lens's length, be favorable to reducing the volume of projection box.
Description
Technical Field
The present invention relates to the field of display technologies, and in particular, to a projection lens and a projection system.
Background
Digital Light Processing (DLP) technology refers to the application of a Digital Micromirror Device (DMD) as a key Processing element to realize Digital optical Processing. The principle is that light emitted by a light source is divided into primary color light, the primary color light is projected on a DMD chip, and the light processed by the DMD chip is imaged on a projection screen through a projection lens. In terms of the technical principle of the DLP, it has the advantages of minimal signal noise, precise gray scale, high reflectivity, seamless image display, high reliability, and the like.
The DLP spliced screen is formed by splicing a plurality of rear projection display units, and is mainly characterized in that the splicing seam is small and can be controlled within 0.5 mm. Based on its advantages, DLP tiled screens are used as background or display in more and more fields in recent years. The conventional DLP tiled screen usually uses a Light Emitting Diode (LED) as a Light source, but the display brightness is not high, about 1000-. However, after the laser light source is widely marketed, the laser light source is applied to the DLP spliced screen, and the light energy can be improved by adopting a DMD of 0.65 "or 0.66", but the existing related projection lens adopts a box body direct projection, so that the box body volume is too large when the DMD of 0.65 "or 0.66" is adapted, and the existing related projection lens cannot be provided with an image offset mirror group because the working distance BFL is small (generally about 35 mm) thereafter, the resolution is limited to be less than 2K, and the display of the 4K resolution cannot be realized.
Disclosure of Invention
The embodiment of the invention provides a projection lens and a projection system, which do not increase the volume of a projection box body when being applied to a laser light source and can realize display with 4K resolution.
In a first aspect, the present invention provides a projection lens, comprising: the lens comprises a first lens group, a second lens group, a third lens group, a fourth lens group, an aperture diaphragm positioned between the first lens group and the second lens group, and a light path steering assembly positioned on one side of the second lens group departing from the aperture diaphragm;
the first lens group is used for imaging the incident beam to form an entrance pupil of the aperture diaphragm; the second lens group is used for imaging the exit pupil of the aperture diaphragm; the third lens group is positioned on the reflected light path of the light path steering component and is used for eliminating the aberration of the projection lens; the fourth lens group is positioned between the light path steering component and the third lens group and is used for eliminating the chromatic aberration of the projection lens;
the light path emitted by the second lens group to the light path steering component and the reflected light path of the light path steering component form a set included angle;
the focal lengths of the first lens group, the second lens group, the third lens group, and the fourth lens group satisfy the following relational expressions:
2.7<｜F1/F｜<5.05；
6.5<｜F2/F｜<12.1；
1.5<｜F3/F｜<2.85；
wherein F denotes an equivalent focal length of the projection lens, F1 denotes an equivalent focal length of the first lens group, F2 denotes an equivalent focal length of an optical system including the second lens group, the optical path turning unit, and the fourth lens group, and F3 denotes an equivalent focal length of the third lens group.
Optionally, a distance between the first lens group and the optical path steering assembly along the main optical axis direction satisfies the following relation:
0.882<L1/L2<1.028；
wherein L1 represents the total length of the first lens group along the main optical axis, and L2 represents the distance between the optical path turning component and the first lens group along the main optical axis.
Optionally, a total length of the second lens group, the optical path turning component, and the fourth lens group along the main optical axis direction satisfies the following relation:
0.218<L3/L<0.308；
wherein L3 represents a total length of the second lens group, the optical path turning element and the fourth lens group along a main optical axis direction, and L represents a total length of the projection system along the main optical axis direction.
Optionally, a distance between the third lens group and the optical path steering assembly along the main optical axis direction satisfies the following relation:
1.385<L4/L5<1.954；
wherein L4 represents the total length of the third lens element along the main optical axis, and L5 represents the distance between the third lens element and the optical path turning component along the main optical axis.
Optionally, the set included angle is 45 degrees to 120 degrees.
Optionally, the optical path turning component is one or a combination of a plane mirror, a curved mirror, or a prism.
Optionally, the projection ratio of the projection lens is 0.550-0.620.
Optionally, the first lens group includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the second lens group includes: a seventh lens; wherein,
diopters of the first lens and the fifth lens are negative, and diopters of the second lens, the third lens, the fourth lens, the sixth lens and the seventh lens are positive.
Optionally, the first lens and the second lens are cemented with each other, and the fifth lens and the sixth lens are cemented with each other.
Optionally, the third lens group includes: an eighth lens and a ninth lens; the diopter of the eighth lens is negative, and the diopter of the ninth lens is positive.
Optionally, the ninth lens is an aspheric lens.
Optionally, the fourth lens group includes: a tenth lens and an eleventh lens; diopter of the tenth lens is positive, and diopter of the eleventh lens is negative.
Alternatively, the tenth lens and the eleventh lens are cemented to each other.
In a second aspect, the present invention provides a projection system comprising: the projection lens comprises a light source, a light valve arranged along the light emergent direction of the light source, an image shift mirror group and any one projection lens.
Optionally, a rear working distance BFL of the projection lens and a distance L2 between the reflector in the projection lens and the first lens group along the optical axis direction satisfy a relationship: 0.8< BFL/L2<1.0, wherein BFL is the distance from the light valve to the first lens in the direction of the optical axis.
Optionally, the back working distance of the projection lens is BFL and is 41 mm-44 mm.
The invention has the following beneficial effects:
the invention provides a projection lens and a projection system, comprising: the lens comprises a first lens group, a second lens group, a third lens group, a fourth lens group, an aperture diaphragm positioned between the first lens group and the second lens group, and a light path steering assembly positioned on one side of the second lens group departing from the aperture diaphragm; the first lens group is used for imaging the incident beam to form an entrance pupil of the aperture diaphragm; the second lens group is used for imaging the exit pupil of the aperture diaphragm; the third lens group is positioned on the reflected light path of the light path steering component and is used for eliminating the aberration of the projection lens; the fourth lens group is positioned between the light path steering component and the third lens group and is used for eliminating the chromatic aberration of the projection lens; the light path emitted by the second lens group to the light path steering component and the reflected light path of the light path steering component form a set included angle;
the focal lengths of the first lens group, the second lens group, the third lens group, and the fourth lens group satisfy the following relational expressions:
2.7<｜F1/F｜<5.05；
6.5<｜F2/F｜<12.1；
1.5<｜F3/F｜<2.85；
wherein F denotes an equivalent focal length of the projection lens, F1 denotes an equivalent focal length of the first lens group, F2 denotes an equivalent focal length of an optical system including the second lens group, the optical path turning unit, and the fourth lens group, and F3 denotes an equivalent focal length of the third lens group. The optical axis of the projection lens is turned by adopting a reflection light path mode, so that the length of the projection lens is reduced, and the volume of the projection box body is reduced. Meanwhile, due to the arrangement of the focal lengths of the first lens group, the second lens group, the third lens group and the fourth lens group, the projection lens can be ensured to have a longer rear working distance of more than 41mm, so that enough space is reserved for configuring the image shift lens group, and the display of 4K resolution is realized.
Drawings
Fig. 1 is a schematic structural diagram of a projection lens according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a projection system according to an embodiment of the present invention;
FIG. 3 is a simulation diagram of an image of a projection system provided by an embodiment of the present invention;
FIG. 4 is a diagram illustrating an imaging effect of a projection system according to an embodiment of the present invention;
fig. 5 is a MTF graph of a projection system according to an embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a projection lens and a projection system, which do not increase the volume of a projection box body when being applied to a laser light source and can realize display with 4K resolution.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is further described with reference to the accompanying drawings and examples. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art.
It should be noted that in the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The invention can be implemented in a number of ways different from those described herein and similar generalizations can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
The following describes a projection lens and a projection system provided in an embodiment of the present invention with reference to the accompanying drawings. The thicknesses and shapes of the respective components in the drawings do not reflect the true scale of the display device, and are merely intended to schematically illustrate the present invention.
As shown in fig. 1, a projection lens provided in an embodiment of the present invention includes: a first optical system 11, a second optical system 12, and an optical path turning component 13 located between the first optical system 11 and the second optical system 12. The first optical system 11 includes a first lens group 111, a second lens group 112, and an aperture stop 113 located between the first lens group and the second lens group; the second optical system 12 includes a third lens group 121 and a fourth lens group 122, and the optical path turning component 13 is located on the side of the second lens group 112 facing away from the aperture stop 113.
The first lens group 111 is used for imaging an incident beam to form an entrance pupil of an aperture stop; the second lens group 112 is for imaging an exit pupil of the aperture stop 113; the third lens 121 group is located on the reflected light path of the light path turning component 13, and is used for eliminating the aberration of the projection lens; the fourth lens group 122 is located between the light path turning component 13 and the third lens group 121, and is used for eliminating the chromatic aberration of the projection lens;
the light path emitted from the second lens group 112 to the light path turning component 13 forms a set included angle with the reflected light path of the light path turning component 13;
in practical applications, the second lens group 112, the optical path turning component 13 and the fourth lens group 122 can be integrally mounted to have an equivalent focal length F2, and if the projection lens has an equivalent focal length F, the first lens group 111 has an equivalent focal length F1, and the third lens group has an equivalent focal length F3, the projection lens shown in fig. 1 can satisfy the following relationships:
2.7<｜F1/F｜<5.05；
6.5<｜F2/F｜<12.1；
1.5<｜F3/F｜<2.85；
the first optical system 11 is configured to perform a first imaging on an incident light beam, and form a first image between the first optical system 11 and the optical path turning component 13;
an optical path turning component 13 for reflecting the first image of the first optical system 11 into the second optical system 12;
the second optical system 12 is used for carrying out second imaging on the first imaging reflected by the light path turning component 13 to form second imaging;
the main optical axis OP of the first optical system 11 and the main optical axis OQ of the second optical system 12 form a predetermined angle.
In practical applications, the projection lens provided in the embodiment of the present invention is a secondary imaging structure, an incident beam enters the first optical system and then is subjected to a primary imaging between the first optical system and the optical path turning component, and the primary imaging is reflected by the optical path turning component and then passes through the second optical system to form a secondary undistorted image on an image side of the second optical system. The optical axis of the projection lens is turned by adopting a reflection type optical path, so that the length of the projection lens is reduced, and the reduction of the volume of the projection box body is facilitated. Meanwhile, due to the arrangement of the focal lengths of the first lens group, the second lens group, the third lens group and the fourth lens group, the projection lens can be ensured to have a longer rear working distance of more than 41mm, so that enough space is reserved for configuring the image shift lens group, and the display of 4K resolution is realized.
In practical implementation, as shown in fig. 1, an included angle α between the main optical axis OP of the first optical system 11 and the main optical axis OQ of the second optical system 12 may be set between 45 degrees and 90 degrees, and compared with a direct projection type projection lens, the projection lens provided in the embodiment of the present invention may reduce the length of the projection lens in the direction of the main optical axis OP, thereby enabling the projection box to be miniaturized.
In practical applications, the angle of the optical path turning component 13 and the angle of the second optical system 12 are rotated to make the main optical axis OP of the first optical system and the main optical axis OQ of the second optical system have different included angles. For example, the optical path turning component 13 may be set at an angle of 45 degrees with the horizontal direction, so that the angle α between the main optical axis OP of the first optical system 11 and the main optical axis OQ of the second optical system 12 is 90 degrees. In addition, the angles of the optical path turning component 13 and the second optical system 12 can be further rotated, so that the included angle α between the main optical axis OP of the first optical system 11 and the main optical axis OQ of the second optical system 12 is greater than 90 degrees or less than 90 degrees. However, the too large α angle is not favorable for reducing the length of the projection lens, and the too small α angle is easy to make the reflected light incident on other elements except the second optical system, so that in practical application, the included angle α needs to be set within a reasonable range according to specific requirements, and specific data thereof is not limited herein.
In one embodiment of the present invention, the aperture stop 113 is used to limit the amount of light energy entering the optical system behind the aperture stop, i.e., to limit the imaging beam at points on-axis, and also to limit the imaging beam at points off-axis. Therefore, the range of the imaging surface and the brightness of the imaging surface can be controlled, and the imaging effect of on-axis point imaging can be improved due to the effect of limiting off-axis point imaging light. While the entrance pupil of the aperture stop can be controlled by designing the number of lenses in the first lens group 111 and the parameters, the parameters of the aperture stop in combination can influence its exit pupil.
In an embodiment of the present invention, if the total length of the first lens group 111 along the main optical axis direction is L1, and the distance between the optical path turning component 13 and the first lens group 111 along the main optical axis is L2, then: 0.882< L1/L2< 1.028.
In an embodiment of the present invention, the second lens group 112, the optical path turning component 13, and the fourth lens group 122 are integrally mounted, a total length of the three along the main optical axis direction is L3, and a total length of the projection lens along the main optical axis direction is L, so that: 0.218< L3/L < 0.308.
In an embodiment of the present invention, if the total length of the third lens group 121 along the main optical axis direction is L4, and the distance between the optical path turning component 13 and the third lens group 121 along the main optical axis is L5, then: 1.385< L4/L5< 1.954.
The projection lens provided by the embodiment of the invention is suitable for a laser light source, the structural form of the projection lens can be maintained by setting the projection lens to meet the parameters of the relational expressions, different rear working distances are compatible, the projection lens can bear more than 3000lm of luminous flux (all lenses are required to be made of glass materials), different projection sizes are compatible, a short-focus lens with 4K resolution can be met, and the size of a projection box body is favorably reduced.
Further, as shown in fig. 1, the first lens group 111 includes: first lensl 1 A second lens elementl 2 A third lens elementl 3 The fourth lens elementl 4 The fifth lens elementl 5 And a sixth lensl 6 (ii) a The second lens group 112 includes: seventh lens elementl 7 。
Wherein the first lensl 1 And a fifth lensl 5 All diopters of the second lens are negativel 2 A third lens elementl 3 The fourth lens elementl 4 The sixth lens elementl 6 And a seventh lensl 7 All diopters of (a) are positive.
In practice, the first lensl 1 May be a biconcave lens, a second lensl 2 May be a biconvex lens, a third lensl 3 May be a biconvex lens, a fourth lensl 4 May be a biconvex lens, a fifth lensl 5 Can be a biconcave lens, a sixth lensl 6 May be a lenticular lens;
wherein the first lensl 1 And a second lensl 2 Cemented with each other, fifth lensl 5 And a sixth lens elementl 6 And (4) gluing the components with each other.
Specifically, a first lensl 1 Has an Abbe number smaller than that of the second lensl 2 The abbe number of (d); fifth lens elementl 5 Has an Abbe number smaller than that of the sixth lensl 6 The abbe number of (d); the double cemented lens can correct the axial chromatic aberration and vertical chromatic aberration of different spectrums of the projection lens.
Further, as shown in fig. 1, the third lens group 121 includes: eighth lens elementl 8 And a ninth lensl 9 (ii) a Wherein the eighth lensl 8 Has a negative diopter, and a ninth lensl 9 Is positive. In practice, the eighth lensl 8 May be convex-concave lenses.
Further, as shown in FIG. 1, a ninth lensl 9 May be an aspheric lens. The ninth lensl 9 May be a symmetric aspheric lens. The symmetric aspherical lens can improve astigmatism, coma and distortion. While other lenses may employ spherical lenses.
Further, as shown in fig. 1, fourth lens group 122 includes: tenth lensl 10 And an eleventh lensl 11 (ii) a Tenth lensl 10 Has a positive diopter, and the eleventh lensl 11 Is negative.
In practice, the tenth lensl 10 Can be convex-concave lens, eleventh lensl 11 May be convex-concave lenses.
Wherein the tenth lensl 10 And the eleventh lensl 11 And (4) gluing the components with each other. Specifically, the tenth lensl 10 Has an Abbe number larger than that of the eleventh lensl 11 Abbe number of (2). And a group of cemented lenses is arranged to correct the axial chromatic aberration and the vertical chromatic aberration of the reflected light.
In specific implementation, the optical path turning component 13 may be one or a combination of a plane mirror, a curved mirror, or a prism. The curved surface reflector can be a spherical reflector or a free-form surface reflector; the prism may be a right angle prism or the like. The single plane mirror is used to facilitate the adjustment of the optical path of the projection lens, and in the embodiment of the present invention, only the single plane mirror is used as the optical path turning component 13 for illustration, and in practical applications, the above-mentioned various forms of mirrors, prisms, or combinations thereof may be used to turn the optical path, which is not limited herein.
In practical applications, the projection ratio of the projection lens provided by the embodiment of the invention can reach 0.550-0.620. Wherein, the projection ratio is the ratio of the projection distance to the picture width. The smaller the projection ratio, the larger the width of the projected picture is on the premise of the same projection distance.
The projection lens provided by the embodiment of the invention has a compact integral mechanism, improves the resolving power of the projection lens by setting the diaphragm, correcting the large-field aberration by the aspheric lens and the reflector, and optimizes the temperature drift of the lens under different temperature conditions, thereby realizing the high-resolution imaging quality; meanwhile, the projection lens can simultaneously give consideration to 1080P resolution on the basis of 4K resolution, and can switch DMDs with different specifications, such as DMD chips with different packaging forms of 0.65 'or 0.66', and the like.
Based on the same inventive concept, an embodiment of the present invention further provides a projection system, as shown in fig. 2, the projection system includes: the light source 100, the light valve 200 disposed along the light exit direction of the light source 100, the total reflection prism 300, the image deflecting mirror set 400 and any one of the projection lenses 500.
In practical applications, the projection system may further include the projection screen 600, or a plane such as a wall may be used as the projection screen. The light source 100 may be a laser light source, and the projection lens 500 may be a short-focus lens suitable for a laser light source. The image shift lens assembly 400 may be made of a flat glass, and is disposed between the light valve 200 and the first lens assembly 111 of the projection lens 500 to shift the image by high frequency vibration, thereby achieving 4K resolution.
The projection lens provided by the embodiment of the invention is a secondary imaging framework, an incident beam enters the first optical system and then is subjected to primary imaging between the first optical system and the light path steering component, and the primary imaging is reflected by the light path steering component and then passes through the second optical system to form a secondary undistorted image on the image side of the second optical system. The optical axis of the projection lens is turned by adopting a reflection type optical path, so that the length of the projection lens is reduced, and the reduction of the volume of the projection box body is facilitated. Meanwhile, due to the arrangement of the focal lengths of the first lens group, the second lens group, the third lens group and the fourth lens group, the projection lens can be ensured to have a longer rear working distance of more than 41mm, so that enough space is reserved for configuring the image shift lens group, and the display of 4K resolution is realized.
In one embodiment of the present invention, the rear working distance BFL of the projection lens and the distance L2 from the mirror 13 to the first lens group 111 in the optical axis direction satisfy the relationship: 0.8<BFL/L2<1.0, wherein BFL is from light valve 200 to first lens along optical axisl 1 The distance of (c).
In one embodiment of the present invention, the back working distance BFL of the projection lens 500 is 41mm to 44mm, which is enough to accommodate the image shift lens assembly 400.
As shown in fig. 3, which is an optical simulation diagram of the imaging quality of the projection system according to the embodiment of the present invention, after passing through the light valve 200, the laser beam enters the projection lens 500 through the total reflection prism 300 and the image shift mirror group 400, and the structure of the projection lens in fig. 3 is the same as that of the projection lens shown in fig. 2. As can be seen from fig. 3, the shifts of red light R, green light G and blue light B are small, i.e. the aberration of the projection lens provided by the embodiment of the present invention is small.
As shown in the dot diagram of the projection system shown in fig. 4 imaged on the projection screen, the grid endpoints represent the positions of ideal image points, and "x" represents the positions of actual image points, and it can be known through calculation that the root mean square Spot sizes (RMS Spot sizes) of the light spots projected on the projection screen are all smaller than 0.38 pixel sizes, which meets the imaging requirements.
As shown in fig. 5, the Modulation Transfer Function (MTF) of each color light projected onto the projection screen is greater than 60% for each millimeter of 93 sets of alternating black and white lines (93 lp/mm). Generally, a criterion for evaluating the lens resolving power is that more than 30% is considered acceptable, and more than 50% is considered to be better. As can be seen from the dot sequence diagram shown in fig. 4 and the modulation transfer function curve shown in fig. 5, the projection lens provided by the embodiment of the invention meets the projection requirement of 4K high resolution, and has small smear and finer image quality.
In the above projection system provided by the embodiment of the present invention, the light valve 200 is arranged to the first lens along the optical axisl 1 Distance of (b) is a rear working distance BFL of projection lens 500, and a distance L2 from mirror 13 to first lens group 111 in the optical axis direction may satisfy a relationship: 0.8<BFL/L2<1.0; the relationship between the projection distance between the projection lens 500 and the projection screen and the size of the projection screen may satisfy: the projection distance/projection screen width is less than or equal to 0.62.
For example, when the Effective Focal Length (Effective Focal Length) of the projection lens is 9.41mm, the back working distance BFL is 42.5146mm, and the image shift lens assembly 400 is configured, the resolution can reach 93lp/mm, thereby achieving 4K resolution image quality, and the projection size can be 70-100 inches, and the projection ratio can be 0.550-0.620. Certainly, the projection lens can also be compatible with the situation that no image shift lens group is arranged, at the moment, the resolving power can reach 67 lp/mm, the resolution is 2K, the size of the projected picture is still 70-100 inches, and the projection ratio is 0.550-0.620.
When the effective focal length EFL of the projection lens is 9.41mm, the minimum back working distance BFL is 41mm or maximum back working distance BFL is 44mm, and the image shift mirror group 400 is configured, the resolution can reach 93lp/mm, the 4K resolution image quality can be realized, the size of the projected image can be 70-100 inches, and the projection ratio is 0.550-0.620. Certainly, the projection lens can also be compatible with the situation that no image shift lens group is arranged, at the moment, the resolving power can reach 67 lp/mm, the resolution is 2K, the size of the projected picture is still 70-100 inches, and the projection ratio is 0.550-0.620.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (15)
1. A projection lens, comprising: the lens comprises a first lens group, a second lens group, a third lens group, a fourth lens group, an aperture diaphragm positioned between the first lens group and the second lens group, and a light path steering assembly positioned on one side of the second lens group departing from the aperture diaphragm;
the first lens group is used for imaging the incident beam and forming an entrance pupil of the aperture diaphragm; the second lens group is used for imaging the exit pupil of the aperture stop; the third lens group is positioned on a reflection light path of the light path steering component and is used for eliminating the aberration of the projection lens; the fourth lens group is positioned between the light path steering component and the third lens group and is used for eliminating chromatic aberration of the projection lens;
the light path emitted by the second lens group to the light path steering component and the reflected light path of the light path steering component form a set included angle;
focal lengths of the first lens group, the second lens group, the third lens group, and the fourth lens group satisfy the following relational expressions:
2.7<｜F1/F｜<5.05；
6.5<｜F2/F｜<12.1；
1.5<｜F3/F｜<2.85；
wherein F denotes an equivalent focal length of the projection lens, F1 denotes an equivalent focal length of the first lens group, F2 denotes an equivalent focal length of an optical system constituted by the second lens group, the optical path turning component, and the fourth lens group, and F3 denotes an equivalent focal length of the third lens group;
the distance between the first lens group and the light path steering component along the direction of the main optical axis satisfies the following relational expression:
0.882<L1/L2<1.028；
wherein L1 represents the total length of the first lens group in the main optical axis direction, and L2 represents the distance of the optical path turning component from the first lens group in the main optical axis direction.
2. The projection lens of claim 1, wherein the total length of the second lens group, the optical path turning component and the fourth lens group in the direction of the main optical axis satisfies the following relation:
0.218<L3/L<0.308；
wherein L3 represents a total length of the second lens group, the optical path turning component and the fourth lens group in a main optical axis direction, and L represents a total length of the projection system in the main optical axis direction.
3. The projection lens of claim 1, wherein the distance between the third lens group and the optical path steering component along the direction of the main optical axis satisfies the following relation:
1.385<L4/L5<1.954；
wherein L4 denotes a total length of the third lens group in a main optical axis direction, and L5 denotes a distance of the third lens group from the optical path turning component in the main optical axis direction.
4. The projection lens of any of claims 1 to 3 wherein the set angle is between 45 degrees and 120 degrees.
5. The projection lens of claim 4 wherein the optical path diversion component is one or a combination of a plane mirror, a curved mirror or a prism.
6. The projection lens of claim 5 wherein the projection lens has a throw ratio of 0.550-0.620.
7. The projection lens of claim 6 wherein the first lens group comprises: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the second lens group includes: a seventh lens; wherein,
diopters of the first lens and the fifth lens are negative, and diopters of the second lens, the third lens, the fourth lens, the sixth lens and the seventh lens are positive.
8. The projection lens of claim 7 wherein the first lens is cemented to the second lens and the fifth lens is cemented to the sixth lens.
9. The projection lens of claim 8 wherein the third lens group comprises: an eighth lens and a ninth lens; the diopter of the eighth lens is negative, and the diopter of the ninth lens is positive.
10. The projection lens of claim 9 wherein the ninth lens is an aspheric lens.
11. The projection lens of claim 10 wherein the fourth lens group comprises: a tenth lens and an eleventh lens; the diopter of the tenth lens is positive, and the diopter of the eleventh lens is negative.
12. The projection lens of claim 11 wherein the tenth lens and the eleventh lens are cemented to each other.
13. A projection system, comprising: a light source, a light valve disposed along a light exit direction of the light source, an image shift mirror group, and a projection lens according to any one of claims 1 to 12.
14. The projection system of claim 13, wherein a rear working distance BFL of the projection lens and a distance L2 of the mirror to the first lens group in the optical axis direction satisfy a relationship: 0.8< BFL/L2<1.0, wherein BFL is the distance from the light valve to the first lens in the direction of the optical axis.
15. The projection system of claim 13, wherein the back working distance of the projection lens is BFL 41mm to 44 mm.
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| CN114253054B (en) * | 2020-09-22 | 2025-02-07 | 上旸光学股份有限公司 | Projection optical system |
| CN116299985B (en) * | 2023-05-17 | 2023-08-29 | 歌尔光学科技有限公司 | Projection lens and projection module |
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