HK1125180B - Zoom lens system - Google Patents
Zoom lens system Download PDFInfo
- Publication number
- HK1125180B HK1125180B HK09102396.7A HK09102396A HK1125180B HK 1125180 B HK1125180 B HK 1125180B HK 09102396 A HK09102396 A HK 09102396A HK 1125180 B HK1125180 B HK 1125180B
- Authority
- HK
- Hong Kong
- Prior art keywords
- zoom
- lens
- image
- lens system
- zoom lens
- Prior art date
Links
Description
This application is a partial Continuation of the application of U.S. patent application No. 10/622,914 (application date 2003, 7/18, CIP), which claims priority to U.S. provisional application No. 60/397,882 (application date 2002, 7/22, 3), and the contents of which are incorporated by reference into this application as Part of this application for a given country to which reference is granted.
Technical Field
The present invention relates to an optical lens system for cameras and other optical devices, and particularly to a high performance zoom lens system (high performance zoom lens system) that produces a high quality image within a full zoom range of focal lengths and is capable of an extremely large zoom ratio.
Background
The use of zoom lens systems for all types of photography, such as broadcast television, high definition television ("HDTV"), advanced television ("ATV"), video cameras, cinematography, and still photography, has become increasingly popular. As the use of zoom lens systems has increased, the demand for a wider range of zoom capabilities (i.e., a large zoom ratio) has also increased. For example, zoom ratio capabilities of zoom lens systems used in broadcast television have steadily increased over the years to a maximum of about 101 to 1 at present, but still larger zoom ratios are required. Although the focal length range of a conventional zoom lens system can be increased by using a drop-in extender or other multiplier (multiplier), for example, increasing the focal length range of a broadcast television zoom lens system to 8.9mm to 900mm to 17.8mm to 1800mm to increase telephoto capabilities, this does not change the zoom ratio of about 101 to 1. Furthermore, there are slightly different requirements for broadcast television zoom lens systems for "studio" (indoor) or "live" (outdoor) use, in terms of focal length range and acceptable f-numbers, and it has become conventional practice to employ two different zoom lens systems for indoor and outdoor broadcast television use to maximize the use capabilities for both types.
Furthermore, in addition to the need and desire to use zoom lens systems having a wide range of focal lengths, such lenses must also maintain excellent optical characteristics and performance, which has previously only been achieved by using separate objective lenses having different fixed focal lengths, or zoom lens systems having limited zoom ratios. As the zoom ratio increases, the difficulty of providing a high-performance optical system having excellent characteristics and performance increases. Also, most previously available zoom lens systems with limited zoom range have one or more undesirable limitations, such as: inability to adequately focus throughout the focal range, inability to focus on close objects, lack of adequate optical performance throughout the focal range and focal distance, cost, and larger size for achieving a limited zoom range, etc.
Further, as the zoom range of the lens system increases, the length and weight typically increase, thus increasing the difficulty of maintaining lens and camera stability. Therefore, image stability also becomes a difficult problem in the design of a practical zoom lens system having a large focal length range and zoom ratio.
Further, as the focal length range of the zoom lens system increases, the focus problem generally increases. Although it is not absolutely necessary to perform near focusing at a long focal length of the zoom range, it is necessary to perform near focusing at a smaller focal length. In the past, continuous focusing from infinity to objects at very short distances (e.g., about 8 feet or less) over a fairly large conjugate range has been difficult to achieve. Furthermore, the problem of the final image "breathing" at a shorter focal length (where the perceived size changes as the focal distance changes) must be minimized in order to avoid, for example, one person disappearing from the scene when the focal point changes to another person at a different distance from the lens. These focusing performance requirements, including maintaining the quality of the final image, tend to greatly increase the weight and cost of the zoom lens system unless the size can be minimized and performance maximized by the overall lens design, including glass selection.
Background information on zooming as discussed above, zoom lens systems having a wide focal length range are highly desirable in many photographic applications, including broadcast television, cinematography, and video and still photography. One standard zoom lens system used in these applications has a four-group PN (P or N) P structure, where P represents a group having at least one lens element, where the lens group has positive power, and N represents a group having at least one lens element, where the lens group has negative power, and the groups are successively identified from object space toward image space as is conventional. The front-most positive group is commonly referred to as a focus group because it is movable to focus the zoom lens system at any focal length position without requiring refocusing for any other focal length of the zoom lens. The second negative group is the variator and it causes a significant magnification change during zooming. The third group (which may typically have positive or negative magnification) is a compensator, and it is movable to ensure that the image plane remains fixed, which may also provide a small magnification change to achieve zooming. The last fourth positive group is often called the prime lens group (prime lens group) because it forms a sharp image.
This basic zoom lens system is suitable for a zoom ratio of 50: 1 or more. However, when the zoom ratio is expanded to about 100: 1, the variator is required to change its object magnification to some extent during zooming, so that aberrations become too large to be practicable and difficult to correct. In addition, with such a large zoom ratio, there is a very large variation in the entrance pupil position (entrance pupil location) during zooming, and this tends to make the frontmost group very large and difficult to correct. Another problem arises from the fact that: in order to reduce the aberration variation due to a large variation in magnification, it is necessary to make the variator have a reduced optical power (optical power). However, the weaker optical power also increases the lens stroke and length of the optical system. For a narrow field of view this is not a problem, but for a wide field of view a larger movement results in an increased chief ray height at the rear of the lens system. This results in an aperture stop with an undesired position, since the requirements for the front or rear of the lens system can be fulfilled, but not simultaneously. If the stop is placed closer to the front of the lens, the front lens element diameter and resulting aberrations are reduced, and if the aperture stop is placed closer to the rear of the lens system, the rear lens diameter and resulting aberrations are reduced.
Disclosure of Invention
General summary of the inventionit is an object of the present invention to provide a zoom lens system to overcome the problems and inefficiency of the existing zoom lens system having a large zoom ratio. Another object is to provide a zoom lens system having a wide focal length zoom range and high performance characteristics for both indoor and outdoor use. It is a further object of the present invention to provide a zoom lens system having a ratio of about 300 to 1, and a zoom range of, for example, about 7mm to 2100mm focal lengths and continuously zooming between the focal lengths. It is still another object of the present invention to provide a high performance zoom lens system with an optical system having: a front zoom lens group for forming an intermediate image, and a rear zoom lens group for magnifying the image to produce an extremely large zoom ratio. It is a further object to provide a zoom lens system having optical image stabilization characteristics. It is still another object to provide a zoom lens system having a focusing lens group capable of focusing accurately over the entire focal length range of the zoom ratio.
Although there are particular benefits to achieving a large zoom ratio, the zoom lens system of the present invention may have conventional zoom ratios, such as those associated with consumer products such as video cameras, still cameras, and the like. It is an additional object of the invention to produce zoom lens systems for these smaller zoom ratio applications.
Other and more specific objects and advantages of the present invention will be readily apparent to those skilled in the art from the various preferred embodiments.
Summary of the invention the present invention overcomes the current obstacles to limiting zoom lens systems to zoom ratios of about 101: 1. The basic idea of the present invention can be considered to be to use a compound zoom lens system (compound zoom lens system) composed of two separate zoom lens portions, wherein the front zoom lens portion forms an intermediate image and the rear zoom lens portion is a relay that transfers the intermediate image formed by the front zoom lens portion to a final image. The overall zoom ratio of the complete compound zoom lens system is equal to the zoom ratio of the front zoom lens multiplied by the zoom ratio of the relay. Therefore, if the zoom ratio of the front zoom lens portion is 20: 1 and the zoom ratio of the relay is 15: 1, the zoom ratio of the entire compound zoom lens system is 300: 1. The present invention can be used to achieve zoom ratios of 300: 1 or greater, which greatly exceed the practical limitations of conventional zoom lens systems.
Drawings
Fig. 1-5 are optical diagrams of a compound zoom lens system of the present invention, used to describe some principles and variations in moving and stationary units used in the system, and some possible embodiments of the present invention, where fig. 1-3 illustrate a system having a zoom ratio of about 300: 1, fig. 4A and 4B have a zoom ratio of about 130: 1, and fig. 5A and 5B have a zoom ratio of about 13: 1 in a superwide angle lens system.
Fig. 6A and 6B are optical diagrams of another embodiment of a zoom lens system of the present invention using three moving zoom lens groups, where the three zoom groups are positioned for a short focal length in fig. 6A and positioned for a long focal length in fig. 6B.
Fig. 7A and 7B are optical diagrams of another embodiment of a zoom lens system of the present invention using four moving zoom lens groups, where the four zoom groups are positioned for a short focal length in fig. 7A and positioned for a long focal length in fig. 7B.
Fig. 8A and 8B are optical diagrams of another embodiment of a zoom lens system of the present invention using four moving zoom lens groups, where the four zoom groups are positioned for a short focal length in fig. 8A and positioned for a long focal length in fig. 8B.
Fig. 9A and 9B are optical diagrams of another embodiment of a zoom lens system of the present invention using three moving zoom lens groups, where the three zoom groups are positioned for a short focal length in fig. 9A and positioned for a long focal length in fig. 9B.
FIGS. 10-62 are diagrams each relating to a single embodiment of a zoom lens system of the present invention having a zoom ratio of about 300: 1, where FIG. 10 is an optical diagram of the entire lens system, FIGS. 11-30 include optical diagrams of the lens system at 20 different representative positions of the movable lens element, FIGS. 31-34 include optical diagrams of lens elements of the focusing unit at only four of the representative positions, FIGS. 35 and 36 illustrate only the front two zoom lens groups at two of the representative positions, FIGS. 37 and 38 illustrate only the rear zoom lens group at two of the representative positions, FIGS. 39-58 include optical ray aberration diagrams of the same 20 representative positions of all the lens elements illustrated in FIGS. 11-30, respectively, FIG. 59 includes a graph of focusing cam movement from minimum (bottom) to infinity (top) with respect to focal distance, fig. 60 includes a graph of three zoom cam movements relative to the system focal length, fig. 61 includes a graph of the focal ratio number of the system at the final image relative to the system focal length, and fig. 62 includes a graph of the diaphragm diameter relative to the system focal length.
Fig. 63 and 64 are an optical diagram and a ray aberration diagram, respectively, of another embodiment of a zoom lens system incorporating a binary (diffractive) surface of the present invention.
FIGS. 65 and 66 are an optical diagram and a ray aberration diagram, respectively, of yet another embodiment of a zoom lens system incorporating a binary (diffractive) surface of the present invention; and FIGS. 67 to 70 are diagrams relating to still another embodiment of the present invention having a zoom ratio of about 400: 1, wherein FIGS. 67 and 68 are optical diagrams at focal lengths of 7.47mm and 2983mm, respectively, and FIGS. 69 and 70 are light aberration graphs at focal lengths of 7.47mm and 2983mm, respectively.
Fig. 71 and 72A to 72D are optical diagrams of an example of still another embodiment of a zoom lens system of the present invention incorporating a mirror for folding the lens in order to increase compactness, in which fig. 72A to 72D show the folded lens in a flat (unfolded) orientation for clarity and illustrate various positions of the zoom group.
FIGS. 73A-73C are optical diagrams of examples of Infrared (IR) embodiments of the zoom lens system of the present invention, illustrating various positions of the zoom groups; and fig. 74 to 76 are graphs of light aberration curves corresponding to the positions of the zoom groups shown in fig. 73A to 73C, respectively.
FIG. 77 illustrates an expanded layout of a second example of an IR embodiment of the zoom lens system of the present invention, with lens elements and surfaces labeled; FIGS. 78A-78F illustrate an expanded layout of the second exemplary IR embodiment in zoom positions Z1-Z6; and FIGS. 79A-79F illustrate the diffraction Modulation Transfer Function (MTF) of selected light rays for the second exemplary IR embodiment in the zoom position shown in FIGS. 78A-78F.
Detailed Description
In the following description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the preferred embodiments of the present invention.
According to its general aspect, the present invention provides a zoom lens system for forming a final image of an object, the system forming a first intermediate real image between the object and the final image, the system comprising:
(a) a first optical unit (e.g., lens elements 8-15 in fig. 10) located between the object and the first intermediate real image, the unit comprising: at least one optical subunit moved to change the size (magnification) of the first intermediate real image (e.g. lens elements 8 to 11 in fig. 10 are the main source of variation in magnification of the first optical unit); and
(b) a second optical unit (e.g., lens elements 26-33 in fig. 10) located between the first intermediate real image and the final image, at least a portion of which (e.g., one or more optical subunits, or the entire second optical unit) is moved to change the size (magnification) of the final image (e.g., lens elements 26-28 of the second optical unit are moved to change the size of the final image in fig. 10).
Preferably, the zoom lens system includes one or more optical sub-units in either or both of the first and second optical units that are moved to keep the axial position of the final image substantially fixed as the focal length of the system is changed (e.g., lens elements 12-15 in FIG. 10 are the primary source of this function). However, such subunits are not required in all cases (e.g., if the overall optical system has an axially movable sensor).
Preferably, the zoom lens system further includes, in addition to the first and second optical units, a focusing unit (e.g., lens elements 1 to 7 in fig. 10), a pupil imaging unit (e.g., lens elements 16 to 25 in fig. 10), and/or an image stabilizing unit (e.g., lens elements 34 to 39 in fig. 10).
Preferably, the focusing unit is: (1) positioned in front of the first optical unit, (2) comprises two optical sub-units (e.g., lens element 2 and elements 3 and 4 in fig. 10) that are movable along the optical axis of the zoom lens system, and/or (3) comprises seven or less lens elements.
Preferably, the image stabilizing unit includes: (1) at least one lens element (e.g., lens elements 34-36 in fig. 10) that is laterally movable outside the optical axis of the system, and/or (2) at least one lens element (e.g., lens elements 37-39 in fig. 10) that is movable along the optical axis. The light passing through the system is preferably substantially collimated between said laterally and axially movable lens elements of the image stabilization unit.
In addition to the first intermediate real image, the zoom lens system of the present invention may form an additional intermediate real image between the object and the final image. The system may comprise additional optical units for changing the size (magnification) of those additional intermediate real images in addition to the first and second units.
Preferably, the first intermediate real image is formed in an air space between optical elements of the zoom lens system (e.g., lens elements used in the system, prisms, fold mirrors, etc.) and does not pass through any surface of the optical elements during zooming. When more than one intermediate real image is formed, this is preferably also the case for all intermediate images.
The first optical unit in combination with the other units of the system may have the form of a conventional zoom lens. Similarly, the second optical unit in combination with the other units of the system may have a conventional zoom lens form. Thus, the overall system can be seen as a "compound" of two conventional zoom lenses, with (according to the invention) control of pupil imaging between the compound zoom lenses.
The overall system can also be considered as: a front zoom lens to form an intermediate image, and a relay system (relay system) to receive the intermediate image and change its magnification to form a final image.
These methods for describing the zoom lens system of the present invention are used herein in the detailed discussion of various aspects of the present invention. While these methods provide a convenient way to describe the present invention, it should be understood that the invention is not limited to these descriptions and that various embodiments and applications of the invention may not be fully amenable to such descriptions.
According to a further aspect, the present invention provides a zoom lens system for forming a final image of an object, the system having a range of focal lengths between a maximum focal length and a minimum focal length, and forming at least a first intermediate real image between the object and the final image for all focal lengths within the range, the system comprising:
(a) a first lens unit having a focal length that is varied to change a size (magnification) of a first intermediate real image, the first lens unit being located between the object and the first intermediate real image for all focal lengths within the range; and
(b) a second lens unit for changing a size (magnification) of the final image, the second lens unit being located between the first intermediate real image and the final image for all focal lengths within the range.
According to an additional aspect, the invention provides a zoom lens system comprising a variable focal length front lens unit forming an intermediate real image, and a variable magnification rear lens unit forming an image of the intermediate image, preferably a real image.
According to a further aspect, the present invention provides a compound zoom lens system that collects radiation from an object space and delivers the radiation to a final image in an image space, the system comprising a plurality of zoom lens portions, the zoom lens portions comprising: a first zoom lens portion forming an intermediate image of radiation from the object space, and a last zoom lens portion forming a final image in the image space.
According to a further additional aspect, the invention provides a zoom lens system for forming a final image of an object, the system having an optical axis, a front lens surface, an aperture stop, and a chief ray (chief ray) traversing the optical axis at the aperture stop, the system comprising: first and second lens units moved to change a focal length of the system, wherein:
(a) between the front lens surface and the final image, a chief ray traverses the optical axis at least one other location than the aperture stop for all focal lengths of the system; and
(b) the system forms an intermediate real image between the first and second lens units for all focal lengths of the system.
Description of some zoom principles and systems of the invention there are unique aspects of compound zoom lens systems (i.e., front zoom/zoom relay systems) that achieve an exceptionally high degree of optical correction to be achieved. A simplified situation is temporarily envisaged in which a complete zoom movement occurs in stages. In the first stage, the repeater is initially set at a short focal length position that provides a small magnification of the intermediate image. Thus, the object conjugate of the repeater will have a small numerical aperture NA, and its image conjugate will have a large numerical aperture NA. (as conventionally defined, the numerical aperture "NA" is equal to the sine of the apex angle of the largest cone of meridional rays (meridional rays) that can enter or exit the optical system or element multiplied by the index of refraction of the medium in which the cone apex is located; and in the lens system optical specifications set forth below, the f-number is equal to the inverse of twice NA, i.e., 1/2 xNA). Since the NA of the relay in object space is equal to the NA of the front zoom lens portion in image space, it is clear that at this first stage only the front zoom lens portion needs to be appropriately corrected to obtain a small NA.
In the second stage, the front zoom lens portion is fixed at its long focal length position, and the relay then zooms to magnify the intermediate image to an increasing extent. As the focal length of the system increases during this second stage, the image NA of the relay becomes smaller and the object NA of the relay becomes larger. Therefore, the image NA of the front zoom lens portion also has to be large. At the same time, however, the actual used radial portion of the intermediate image becomes smaller as the system focal length becomes larger.
Therefore, it is not necessary to correct the front zoom lens portion to obtain a large intermediate image size and a large relative aperture (NA) at the same time. In fact, it needs to be corrected to obtain a large intermediate image size at small apertures, and a small intermediate image size at large apertures. This makes the design of the front zoom lens portion much easier than that of a conventional zoom lens system having the same zoom ratio as that of the front zoom lens system of the present invention.
Also, the repeater need only be calibrated to obtain a large image NA and large object size at the small magnification end of its focal length. At the other end of its focal length zoom range, the object size is small and the image NA is also small.
As discussed above, the zoom lens system of the present invention preferably includes a pupil imaging unit in addition to the front zoom lens portion and the relay. This unit is used to image the exit pupil of the front zoom lens portion into the entrance pupil of the relay. By selecting an appropriate power (power), not only can the lens diameter of the relay and the accompanying aberrations be minimized, but control of the exit pupil position of the system can be improved.
As also discussed above, the intermediate image formed by the front zoom lens portion is preferably located at a position that does not pass through any lens surface when the system is zoomed from its minimum focal length to its maximum focal length. By being between the front zoom lens portion and the rear relay, the intermediate image is automatically behind the axially moving lens unit that provides the zoom in the front zoom lens portion and in front of any axially moving lens unit that provides the zoom in the rear zoom portion. Since in some embodiments of the invention the intermediate image may move during zooming, the positions of the lens surfaces of either side of the intermediate image (whether those surfaces are fixed or moving) are preferably selected so that, although the intermediate image moves, the surfaces remain spaced from the intermediate image throughout the entire zoom range of the system.
Various ones of the above features of the present invention are illustrated in fig. 1-3 for a PNPP-PNPP compound zoom lens system having a zoom ratio of about 300: 1. As designed in FIG. 1, this compound zoom lens system has a front zoom lens portion with a zoom ratio of about 20: 1, and a rear zoom lens portion (relay) with a zoom ratio of about 15: 1. The team and its positive or negative magnification sign are also designed in fig. 1. In this compound zoom lens system, the relay is fixed when the front zoom lens portion is operated from its shortest focal length position (shown in fig. 1) to its longest focal length position (shown in fig. 2). Once the front zoom lens portion reaches its long focal length position, the relay starts to change the magnification of the intermediate image to further increase the focal length of the compound system. FIG. 3 depicts the system in its maximum focal length state, with the front zoom lens portion in its maximum focal length position and the rear zoom (relay) lens portion in its maximum magnification position.
Fig. 1 and 2 show a small NA at the intermediate image plane and a large NA at the final image plane that occur during the initial stage of zooming from short to long. During this stage, the size of the intermediate image is larger, as shown. Fig. 3 shows that at the longest focal length position, NA becomes larger at the intermediate image and smaller at the final image.
Note that in this example, there are 8 zoom lens groups, but only 4 of them can be independently moved for zooming. Groups 1, 4, 5 and 8 are all fixed relative to the final image. However, during focusing, one or more of these sets may be moved.
The scenarios outlined herein are for exemplary purposes. In practice, the zoom motion need not be explicitly divided into two stages, and thus the relay or a portion thereof may move during the initial zoom stage and not just near the long end of the focal length.
The examples of fig. 1 to 3 described above have a PNPP-PNPP configuration, where the dashed line "-" indicates the end of the front zoom lens portion. Both the front zoom lens portion and the rear zoom lens portion have variator and compensator zoom groups. One advantage of this configuration is that the intermediate image can be absolutely fixed, if desired. Fixing the image will prevent it from passing through any optical surface, which may reveal surface imperfections and dark images that will appear at the final image. The use of a four-group configuration in the rear zoom lens portion also allows for better control of the exit pupil position, which may be important to match the telecentricity (telecentricity) requirements of certain image sensors.
It is possible to exclude one of the compensators if intermediate image shifts can be tolerated. In this case the post-compensator is preferably removed, since it only moves when the beam diameter is relatively small. Thus, the resulting configuration would be a PNPP-PNP configuration.
For both configurations, care must be taken to match the exit pupil of the front zoom lens portion with the entrance pupil of the relay. For this purpose, it is advantageous to use an eyepiece-like group (eyepiece-like group) which can convert the diverging beam emanating from the intermediate image into an approximately parallel beam to enter a normal PNP or PNPP type zoom lens system corrected to obtain an infinite conjugate.
One aspect of this type of high-speed (large aperture) ultra-wide focal length range compound zoom lens system is that the intermediate image and all of its image distortions are highly magnified by the zoom group in the relay in the long focal length position. This puts severe requirements on the correction of the secondary chromatic aberration in the front zoom lens part and especially in the focus group. To achieve this correction, it is necessary to use at least one and more likely several fluoro-crown glass elements. Alternatively, calcium fluoride or binary (diffractive) surfaces may also be used for this purpose.
A variety of binary (diffractive) surfaces (diffractive elements) can be used in the practice of the present invention. For example, for some applications, one or more diffractive optical elements of the type disclosed in U.S. patent No. 6,507,437, assigned to Canon, may be used alone or in combination with other methods for correcting chromatic aberration.
An important advantage of using a PNPP-PNPP or PNPP-PNP configuration on existing zoom lens systems is that both the front and rear zoom lens portion (relay) systems can have very large zoom ratios. In this case, it is reasonable to have a zoom ratio of 20: 1 or more for the front zoom lens portion or the rear zoom lens portion, so that it is possible to achieve an overall zoom ratio of 400: 1 or more. However, if such a large zoom ratio is not required, the system may be significantly simplified by using a repeater with an NP configuration having two mobile groups instead. This relay is very useful for large aperture applications where the total zoom ratio in the relay is about 3: 1 to about 10: 1. An example of a compound zoom lens system having an approximately 130: 1 zoom ratio is shown in fig. 4A and 4B, with a front zoom lens portion having an approximately 20: 1 zoom ratio PNPP and a relay having an approximately 6.5: 1 zoom ratio fig. 4A illustrates a minimum focal length of approximately 7mm and fig. 4B illustrates a maximum focal length of approximately 900 mm. One disadvantage of this configuration is that the last lens group is not fixed; it must be designed to withstand significant magnification changes at large apertures, which makes it somewhat difficult to design.
A more simplified configuration consisting of an NP front zoom lens portion and an NP rear zoom lens portion (relay) can also be designed, but in this case the maximum zoom ratio will be reduced. Obviously, the techniques can be generalized to encompass a large number of combinations of various zoom lens configurations for the front zoom lens portion and for the rear zoom lens portion. For example, a high zoom ratio, ultra-wide angle zoom lens system may be constructed by using an NP, NPP, or NPNP ultra-wide angle front zoom lens portion having a zoom ratio of about 2: 1, and an NP rear zoom lens portion (relay) having a zoom ratio of about 6.5: 1. The result will be a compound zoom lens system with a zoom ratio of about 13: 1, with a maximum full field of view of up to 100 degrees or more. FIGS. 5A and 5B illustrate a 4.4mm-57.2mm, f/3-f/7 compound zoom lens system with a zoom ratio of about 13: 1 for an 2/3 ″ sensor. The compound zoom lens system has a full field angle at the wide-angle end of greater than 102 degrees. It is apparent that a PNPP-type rear zoom lens portion (relay) similar to that used in fig. 1-3 can be used with this same ultra-wide angle front zoom lens portion to produce an ultra-wide angle compound zoom lens system having a zoom ratio of about 30: 1.
The presence of intermediate images is common to all of these configurations and this provides some unique possibilities for aberration correction not normally achievable in prior art zoom lens system types. For example, an aspheric surface placed on an element located near the intermediate image may have a strong effect on distortion and other field aberrations without interfering with the spherical aberration correction. Advantages of placing an aspheric surface in this region include: the tolerances are more tolerant because the beam diameter is smaller and the elements themselves are smaller. This means that the cost of using an aspheric surface in this region is minimal.
Detailed description of preferred embodiments as described above in the section entitled "description of some zoom principles and systems of the invention", each of the embodiments of the invention disclosed herein includes a front zoom lens portion and a rear zoom lens portion, thereby forming a compound zoom lens system. An intermediate image is formed behind the front zoom lens portion, whereby the rear zoom lens portion acts as a zoom relay to magnify the intermediate image in order to provide a magnified final image for capture by a photo detector or capture device of any other kind in a film or camera, such as a Charge Coupled Device (CCD). For the purposes of this application, the term "camera" is used generically to describe any kind of light detection or capture device that may be placed behind the lens system of the present invention, including a still, video or movie capture device, whether containing film, video tape, compact disc, CMOS, CCD or another storage medium, or an eyepiece or human eye. Any such "camera" may include additional lens elements. Currently, it is contemplated that the front zoom lens portion will include two moving zoom lens groups and the rear zoom lens portion will include one or two moving zoom lens groups, but it will be appreciated that more or fewer moving zoom lens groups may be used without departing from the invention. Also, it is currently contemplated that only one intermediate image will be formed in the entire compound zoom lens system, but other embodiments of the present invention may form more than one intermediate image.
The compound zoom lens system of the present invention preferably further comprises a focusing lens group in addition to the front and rear zoom lens portions and the rear zoom lens portion. The focusing lens group is preferably positioned in front of the lens system as shown in each of the embodiments disclosed herein, but it is possible in other embodiments of the invention to achieve some and possibly all focusing elsewhere in the compound zoom lens system.
When a single intermediate image is formed in such a compound zoom lens system, the final image is inverted and reversed from left to right from the conventional orientation produced by the objective lens, and thus the image orientation must be adjusted by the camera. For video cameras that use a single chip for the detector, it is possible to rotate the chip only 180 degrees around the optical axis so that the chip reads the final image as if it were conventionally oriented. Another solution to the orientation problem of video cameras is to reverse the order in which the data is scanned, i.e., instead of reading the data from left to right and from top to bottom, the data is read from right to left and from bottom to top to achieve a conventional orientation. Yet another solution to the orientation problem of video cameras that use the "frame store" feature to store an entire frame on a memory chip before it is transmitted for use is: the stored frames are only transferred from the frame store memory (frame store memory) in the reverse order. For a motion picture film camera, the entire camera with the film cassette can be inverted to thus run the film up to correct for image orientation. Another solution to image orientation in a motion picture film camera that is used in a conventional manner and employs the zoom lens system of the present invention is to use digital compositing (digital compositing) in which the film is digitally scanned and then, for example, after a digital operation, an image is applied to the new film in a conventional orientation. The use of a prism in or in conjunction with the lens system of the present invention will also correct the orientation of the final image. Care must be taken with this method so that the prism does not cause excessive degradation of the quality of the final image (especially for high performance applications of the lens system of the present invention).
Due to the compound zoom configuration of the zoom lens system of the present invention, the body of the compound lens system will typically be of sufficient length, and thus any deflection or vibration of the lens system relative to the camera may result in unacceptable deflection or vibration of the final image in the camera. Therefore, at least for the compound zoom lens system of the present invention having a large zoom ratio, a long focal length, and/or a sufficient length, it is expected that an image stabilization configuration will be used. While electronic image stabilization may be suitable for some video camera applications, for higher performance zoom lens system applications, it is preferred to include the optical image stabilization configuration in the body of the compound zoom lens system, and preferably near the camera end of the lens system, such as is included in the embodiments of fig. 10-62 described below.
While it is more desirable to design and construct the compound zoom lens system of the present invention as a one-piece unit for maximum performance, it is also possible to use two or more separable components to achieve the basic features. For example, a conventional zoom lens or a modified form thereof may be used as the front zoom lens portion, and as such the rear zoom lens portion may comprise a separate accessory that relays and changes the magnification (e.g., zooming) of the image formed by the front zoom lens portion (which becomes an "intermediate image") to form the final image. Thus, the front zoom lens portion will provide one zoom ratio and the rear attachment zoom portion will provide another zoom ratio. However, for such combinations, pupil imaging should be controlled to obtain a final image with acceptable optical quality. Other such combinations of conventional and/or modified lens portions may also be used to provide the compound zoom lens system of the present invention.
Fig. 6A to 9B illustrate optical diagrams of four different embodiments of the zoom lens system of the present invention. At the rightmost side of each of fig. 6A-9B, the two rectangular boxes represent the prism boxes of a conventional 3CCD 2/3 "detector that is part of the video camera and therefore not part of the zoom lens system.
The following table lists the lens system optical design, the variable thickness position of the respective surfaces, and the focal length and magnification of the respective surface sets for each of those four embodiments. In view of the large number of surfaces and the small scale of the optical diagram including all elements, only some of the surfaces in fig. 6A-9B corresponding to the surfaces set forth in the lens system optical design are labeled for simplicity and clarity. A more detailed explanation of the table is provided after the table.
Tables of FIG. 6A and FIG. 6B
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S11, S14, S28, S42, S45 and S50 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S11 are: the coefficients for surface S42 are:
K＝-0.2197954 K＝-0.0460624
A＝9.0593667e-009 A＝-2.6257869e-007
B＝1.7844857e-013 B＝-2.5945471e-010
C＝1.5060271e-017 C＝2.4316558e-013
D＝-9.7397917e-023 D＝-1.2995378e-016
the coefficients for surface S14 are: the coefficients for surface S45 are:
K＝0.7048333 K＝0.0
A＝-3.0463508e-007 A＝-1.1056187e-005
B＝-1.1451797e-010 B＝2.8606310e-008
C＝3.4844023e-014 C＝-1.2655154e-010
D＝-2.2107339e-017 D＝2.2826095e-013
the coefficients for surface S28 are: the coefficients for surface S50 are:
K＝-0.9252575 K＝0.0
A＝-1.8743376e-007 A＝-1.8976230e-006
B＝-1.0562170e-009 B＝1.2489903e-009
C＝2.8892387e-012 C＝-2.3703340e-012
D＝-3.6671423e-015 D＝3.0161146e-015
focal length of surface group
S1-S12 266.611
S13-S19 -46.300
S20-S26 91.566
S27-S43 55.841
S44-S47 -32.720
S48-S62 42.594
Magnification of surface group
| Surface of | P1M’ | P1MP’ | P2M’ | P2MP’ | P3M’ | P3MP’ | P4M’ | P4MP’ |
| S1-S12 | 0.000 | 0.754 | 0.000 | 0.672 | 0.000 | 0.492 | 0.000 | 0.320 |
| S13-S19 | -0.238 | 7.670 | -0.268 | 7.215 | -0.374 | 6.275 | -0.599 | 5.828 |
| S20-S26 | -0.350 | 0.876 | -0.385 | 0.843 | -0.495 | 0.746 | -0.699 | 0.550 |
| S27-S43 | 0.871 | -1.159 | 0.870 | -1.159 | 0.854 | -1.159 | 0.844 | -1.159 |
| S44-S47 | 0.321 | -2.846 | 0.322 | -2.829 | 0.325 | -2.794 | 0.327 | -2.793 |
| S48-S62 | -1.170 | -0.304 | -1.170 | -0.305 | -1.170 | -0.308 | -1.170 | -0.308 |
| Surface of | P1M’ | P5MP’ | P6M’ | P6MP’ | P7M’ | P7MP’ | P8M’ | P8MP’ |
| S1-S12 | 0.000 | 0.195 | 0.000 | 0.123 | 0.000 | 0.163 | 0.000 | 0.124 |
| S13-S19 | -1.012 | 7.410 | -1.390 | -119.200 | -1.382 | 4.682 | -1.386 | -141.400 |
| S20-S26 | -0.945 | 0.312 | -1.275 | -0.017 | -0.715 | 0.599 | -1.279 | -0.014 |
| S27-S43 | 0.834 | -1.159 | 0.833 | -1.159 | 0.774 | -1.159 | 0.826 | -1.159 |
| S44-S47 | 0.330 | -2.712 | 0.338 | -2.278 | 0.769 | -0.501 | 0.856 | -0.451 |
| S48-S62 | -1.170 | -0.313 | -1.315 | -0.361 | -2.549 | -0.731 | -2.693 | -0.727 |
Where P1M 'is the lens group magnification of the lens group equal to (incident edge ray angle)/(exit edge ray angle), and P1 MP' is the lens group magnification equal to incident chief ray angle/exit chief ray angle, and so on, up to P8M 'and P8 MP';
the first two symbols represent position numbers, e.g., P1M 'and P1 MP' for position 1.
Tables of FIGS. 7A and 7B
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S13, S16, S19, S20, S30, S47, S54, and S70 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D, E, F, G coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S13 are: the coefficients for surface S20 are: the coefficients for surface S54 are:
K＝-0.1600976 K＝0.0 K＝0.0
A＝6.9210418e-009 A＝3.4619978e-008 A＝-2.743254e-006
B＝2.2313210e-013 B＝4.2692157e-011 B＝-2.133804e-009
C＝1.1852054e-017 C＝-7.0823340e-014 C＝1.668568e-011
D＝-2.0918949e-021 D＝-2.3957687e-017 D＝-1.9544629e014
E＝2.2579263e-025 E＝5.4513203e-020 E＝0.0
F＝8.1799420e-030 F＝-1.4597367e-023 F＝0.0
G＝-1.2582071e-033 G＝-4.1263059e-027 G＝0.0
the coefficients for surface S16 are: the coefficients for surface S30 are: the coefficients for surface S70 are:
K＝0.9059289 K＝-0.8025959 K＝-2.3
A＝-4.3564263e-007 A＝-3.8556154e-007 A＝3.877213e-007
B＝-1.3760665e-010 B＝-5.4410316e-010 B＝4.916800e-010
C＝1.1349273e-014 C＝7.0427510e-012 C＝-1.461192e-012
D＝-3.8588303e-017 D＝-8.5740313e-015 D＝-3.258352e-017
E＝1.5211558e-020 E＝-5.2635786e-017 E＝4.664784e-018
F＝-5.1726796e-025 F＝1.0608042e-019 F＝-4.216175e-021
G＝-2.0900671e-027 G＝7.5783088e-023 G＝0.0
the coefficients for surface S19 are: the coefficients for surface S47 are:
K＝0.0 K＝0.0
A＝-6.5866466e-008 A＝-1.2184510e-005
B＝-3.2305127e-011 B＝1.2115245e-007
C＝-3.5095033e-014 C＝-3.0828524e-010
D＝4.0315700e-017 D＝-5.7252449e-014
E＝-6.1913043e-021 E＝0.0
F＝-2.4403843e 023 F＝0.0
G＝9.0865109e-027 G＝0.0
focal length of surface group
S1-S14 283.564
S15-S21 -52.598
S22-S28 102.619
S29-S58 51.668
S59-S66 -29.319
S67-S69 178.034
S70-S77 70.650
Magnification of surface group
| Surface of | P1M’ | P1MP’ | P2M’ | P2MP’ | P3M’ | P3MP’ | P4M’ | P4MP’ |
| S1-S14 | 0.000 | 0.740 | 0.000 | 0.564 | 0.000 | 0.318 | 0.000 | 0.179 |
| S15-S21 | -0.260 | 7.365 | -0.347 | 6.511 | -0.644 | 6.193 | -1.207 | 7.342 |
| S22-S28 | -0.369 | 0.833 | -0.462 | 0.740 | -0.736 | 0.466 | -0.896 | 0.306 |
| S29-S58 | -2.392 | -0.356 | -2.392 | -0.356 | -2.392 | -0.356 | -2.392 | -0.356 |
| S59-S66 | -0.282 | 25.995 | -0.282 | 25.995 | -0.282 | 25.993 | -0.282 | 25.994 |
| S67-S69 | 14680.000 | 0.231 | 14680.000 | 0.231 | 14680.000 | 0.231 | 14680.000 | 0.231 |
| S70-S77 | 0.000 | 0.447 | 0.000 | 0.447 | 0.000 | 0.447 | 0.000 | 0.447 |
| Surface of | P5M’ | P5MP’ | P6M’ | P6MP’ | P7M’ | P7MP’ |
| S1-S14 | 0.000 | 0.117 | 0.000 | 0.174 | 0.000 | 0.117 |
| S15-S21 | -1.468 | -19.350 | -1.150 | 14.886 | -1.468 | -19.350 |
| S22-S28 | 1.303 | -0.101 | -1.065 | 0.137 | -1.303 | -0.101 |
| S29-S58 | -2.392 | -0.356 | -2.392 | -0.356 | -2.392 | -0.356 |
| S59-S66 | -0.282 | 25.994 | -2.227 | 0.319 | -4.006 | 0.300 |
| S67-S69 | 14680.000 | 0.231 | 271.410 | 2.365 | 81.569 | 1.386 |
| S70-S77 | 0.000 | 0.447 | -0.001 | -0.374 | -0.005 | -1.131 |
Where P1M 'is the lens group magnification of the lens group equal to (incident edge ray angle)/(exit edge ray angle), and P1 MP' is the lens group magnification equal to incident chief ray angle/exit chief ray angle, and so on, up to P7M 'and P7 MP';
the first two symbols represent position numbers, e.g., P1M 'and P1 MP' for position 1.
Tables of FIGS. 8A and 8B
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S12 and S26 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S12 are:
K＝0.0
A＝-1.3820532e-007
B＝-2.7133115e-011
C＝-9.2535195e-015
D＝3.3313103e-018
the coefficients for surface S26 are:
K＝-0.5520119
A＝-1.0148386e-006
B＝-5.9646048e-011
C＝-1.3030573e-013
D＝3.2918363e-016
focal length of surface group
S1-S10 262.599
S11-S17 -50.895
S18-S24 98.756
S25-S47 37.686
S48-S53 -25.559
S54-S56 106.555
S57-S62 81.336
Magnification of surface group
| Surface of | P1M’ | P1MP’ | P2M’ | P2MP’ | P3M’ | P3MP’ | P4M’ | P4MP’ |
| S1-S10 | 0.000 | 0.805 | 0.000 | 0.626 | 0.000 | 0.337 | 0.000 | 0.191 |
| S11-S17 | -0.248 | 7.962 | -0.323 | 7.245 | -0.625 | 7.155 | -1.136 | 9.531 |
| S18-S24 | -0.349 | 0.734 | -0.431 | 0.633 | -0.680 | 0.394 | -0.831 | 0.233 |
| S25-S47 | -1.752 | -0.293 | -1.612 | -0.293 | -1.683 | -0.293 | -1.613 | -0.293 |
| S48-S53 | -0.505 | 5.934 | -0.574 | 4.957 | -0.532 | 5.900 | -0.571 | 5.176 |
| S54-S56 | -1.558 | 1.108 | -1.529 | 1.487 | -1.539 | 1.120 | -1.533 | 1.378 |
| S57-S62 | 0.233 | 1.240 | 0.235 | 3.217 | 0.234 | 1.263 | 0.234 | 2.205 |
| Surface of | P5M’ | P5MP’ | P6M’ | P6MP’ | P7M’ | P7MP’ |
| S1-S10 | 0.000 | 0.130 | 0.000 | 0.184 | 0.000 | 0.120 |
| S11-S17 | -1.263 | -8.111 | -1.246 | 6.886 | -1.285 | -6.384 |
| S18-S24 | -1.324 | -0.233 | -0.748 | 0.350 | -1.444 | -0.301 |
| S25-S47 | -1.813 | -0.293 | -1.890 | -0.293 | -2.412 | -0.293 |
| S48-S53 | -0.496 | 4.492 | -3.524 | 0.483 | -4.060 | 0.347 |
| S54-S56 | -1.600 | 1.750 | -1.939 | 2.244 | -1.904 | 1.880 |
| S57-S62 | 0.230 | -29.370 | 0.234 | -0.833 | 0.231 | -1.610 |
Where P1M 'is the lens group magnification of the lens group equal to (incident edge ray angle)/(exit edge ray angle), and P1 MP' is the lens group magnification equal to incident chief ray angle/exit chief ray angle, and so on, up to P7M 'and P7 MP';
the first two symbols represent position numbers, e.g., P1M 'and P1 MP' for position 1.
Tables of FIGS. 9A and 9B
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S20 and S34 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S20 are:
K＝-0.3254663
A＝-3.65160e-007
B＝-1.14704e-010
C＝-5.60564e-014
D＝-5.86283e-018
the coefficients for surface S34 are:
K＝0.348034
A＝1.350560e-006
B＝2.453070e-009
C＝-2.820340e-012
D＝4.745430e-015
focal length of surface group
S2-S3 -379.209
S4-S5 -597.975
S6-S11 484.131
S12-S18 229.394
S2-S18 262.190
S19-S25 -49.050
S26-S32 79.931
S33-S51 41.254
S52-S57 -26.810
S58-S79 70.920
Magnification of surface group
| Surface of | P1M’ | P1MP’ | P2M’ | P2MP’ | P3M’ | P3MP’ | P4M’ | P4MP’ |
| S2-S3 | 0.000 | 1.732 | 0.066 | 1.710 | 0.129 | 1.696 | 0.000 | 1.971 |
| S4-S5 | 0.599 | 1.754 | 0.594 | 1.563 | 0.59 | 1.425 | 0.599 | 2.388 |
| S6-S11 | 2.150 | 0.529 | 2.229 | 0.608 | 2.304 | 0.682 | 2.150 | 0.374 |
| S12-S18 | -0.537 | 0.642 | -0.537 | 0.642 | -0.537 | 0.642 | -0.537 | 0.53 |
| S2-S18 | 0.000 | 1.030 | -0.047 | 1.043 | -0.094 | 1.058 | 0.000 | 0.934 |
| S19-S25 | -0.185 | 8.447 | -0.185 | 8.447 | -0.185 | 8.447 | -0.206 | 7.952 |
| S26-S32 | -0.252 | 0.756 | -0.252 | 0.756 | -0.252 | 0.756 | -0.252 | 0.731 |
| S33-S51 | -1.446 | -0.378 | -1.446 | -0.378 | -1.446 | -0.378 | -1.442 | -0.378 |
| S52-S57 | -0.673 | 6.392 | -0.673 | 6.392 | -0.673 | 6.392 | -0.676 | 6.392 |
| S58-S79 | -0.611 | 0.966 | -0.611 | 0.966 | -0.611 | 0.966 | -0.611 | 0.966 |
| Surface of | P5M’ | P5MP’ | P6M’ | P6MP’ | P37M’ | P7MP’ | P8M’ | P8MP’ |
| S2-S3 | 0.000 | 2.695 | 0.000 | 6.440 | 0.000 | -4.655 | 0.000 | -1.279 |
| S4-S5 | 0.599 | -24.64 | 0.599 | -0.414 | 0.599 | 0.216 | 0.599 | 0.403 |
| S6-S11 | 2.150 | -0.033 | 2.150 | -1.271 | 2.150 | -127.8 | 2.150 | 4.484 |
| S12-S18 | -0.537 | 0.365 | -0.537 | 0.187 | -0.537 | 0.004 | -01537 | -0.147 |
| S2-S18 | 0.000 | 0.788 | 0.000 | 0.633 | 0.000 | 0.473 | 0.000 | 0.341 |
| S19-S25 | -0.245 | 7.233 | -0.31 | 6.531 | -0.424 | 6.046 | -0.601 | 6.421 |
| S26-S32 | -0.319 | 0.688 | -0.386 | 0.622 | -0.496 | 0.512 | -0.646 | 0.362 |
| S33-S51 | -1.445 | -0.378 | -1.448 | -0.378 | -1.448 | -0.378 | -1.449 | -0.378 |
| S52-S57 | -0.673 | 6.392 | -0.671 | 6.392 | -0.671 | 6.392 | -0.67 | 6.392 |
| S58-S79 | -0.611 | 0.966 | -0.612 | 0.966 | -0.612 | 0.966 | -0.612 | 0.966 |
| Surface of | P9M’ | P9MP’ | P10M’ | P10MP’ | P11M’ | P11MP’ | P12M’ | P12MP’ |
| S2-S3 | 0.000 | -0.736 | 0.000 | -0.549 | 0.000 | -0.387 | 0.000 | -0.365 |
| S4-S5 | 0.599 | 0.468 | 0.599 | 0.496 | 0.599 | 0.522 | 0.599 | 0.526 |
| S6-S11 | 2.150 | 3.296 | 2.150 | 2.964 | 2.150 | 2.701 | 2.150 | 2.668 |
| S12-S18 | -0.537 | -0.234 | -0.537 | -0.279 | -0.537 | -0.330 | -0.537 | -0.338 |
| S2-S18 | 0.000 | 0.265 | 0.000 | 0.225 | 0.000 | 0.180 | 0.000 | 0.173 |
| S19-S25 | -0.771 | 8.327 | -0.894 | 11.79 | -0.983 | -18.95 | -1.004 | -14.68 |
| S26-S32 | -0.770 | 0.233 | -0.846 | 0.152 | -1.064 | -0.084 | -1.092 | -0.107 |
| S33-S51 | -1.431 | -0.378 | -1.406 | -0.378 | 1.344 | -0.378 | -1.359 | -0.378 |
| S52-S57 | -0.692 | 5.731 | -0.728 | 4.790 | -0.916 | 2.531 | -1.194 | 1.491 |
| S58-S79 | -0.611 | 1.263 | -0.611 | 2.227 | -0.611 | -2.992 | -0.610 | -1.604 |
| Surface of | P13M’ | P13MP’ | P14M’ | P14MP’ | P15M’ | P15MP’ | P16M’ | P16MP’ |
| S2-S3 | 0.000 | -0.351 | 0.000 | -0.348 | 0.041 | -0.294 | 0.085 | -0.24 |
| S4-S5 | 0.599 | 0.529 | 0.599 | 0.529 | 0.596 | 0.529 | 0.593 | 0.529 |
| S6-S11 | 2.150 | 2.646 | 2.150 | 2.642 | 2.199 | 2.691 | 2.250 | 2.742 |
| S12-S18 | -0.537 | -0.344 | -0.537 | -0.345 | -0.537 | -0.345 | -0.537 | -0.345 |
| S2-S18 | 0.000 | 0.169 | 0.000 | 0.168 | -0.029 | 0.145 | -0.061 | 0.12 |
| S19-S25 | -0.919 | -5.386 | -0.870 | -3.955 | -0.869 | -3.955 | -0.869 | 3.955 |
| S26-S32 | -1.351 | -0.287 | -1.561 | -0.395 | -1.561 | -0.395 | -1.561 | -0.395 |
| S33-S51 | -1.719 | -0.378 | -2.606 | -0.378 | -2.61 | -0.378 | -2.612 | -0.378 |
| S52-S57 | -2.093 | 0.631 | -3.758 | 0.316 | -3.685 | 0.316 | -3.626 | 0.316 |
| S58-S79 | -0.613 | -1.659 | -0.600 | -7.955 | -0.610 | -7.955 | -0.619 | -7.955 |
| Surface of | P17M’ | P17MP’ |
| S2-S3 | 0.129 | -0.183 |
| S4-S5 | 0.590 | 0.528 |
| S6-S11 | 2.304 | 2.795 |
| S12-S18 | -0.537 | -0.345 |
| S2-S18 | -0.094 | 0.093 |
| S19-S25 | -0.869 | -3.955 |
| S26-S32 | -1.561 | -0.395 |
| S33-S51 | -2.612 | -0.378 |
| S52-S57 | -3.629 | 0.316 |
| S58-S79 | -0.618 | -7.955 |
Where P1M 'is the lens group magnification of the lens group equal to (incident edge ray angle)/(exit edge ray angle), and P1 MP' is the lens group magnification equal to incident chief ray angle/exit chief ray angle, and so on, up to P17M 'and P17 MP';
the first two symbols represent position numbers, e.g., P1M 'and P1 MP' for position 1.
The element group defined by the surfaces 69 to 73 is translated in a direction perpendicular to the optical axis to compensate for image vibration.
In the lens system optical design (optical description) of each of the four embodiments provided above, each surface of a lens element is denoted in the left-hand column ("surface"), the radius of the surface is denoted in the second column ("radius"), the thickness on the optical axis between the surface and the next surface (whether glass or air) is denoted in the third column ("thickness"), the refractive index of a glass lens element is stated in the fourth column ("glass index"), and the dispersion value ("glass dispersion") of the lens element is stated in the fifth column. The surface numbers in the first column "surface" indicate that the surfaces are numbered from left to right in the figure (i.e., from object space to image space) in a conventional manner.
In the left hand or "surface" column of each lens system optical design provided above, the object to be imaged (e.g., photographed) is labeled as "object", the adjustable iris or diaphragm is labeled as "diaphragm", and the final image is labeled as "image". In a third or thickness column of the optical design of the lens system, the adjustable space between lens elements on either side of, for example, a movable zoom group is denoted as "variable". EFL, radius and thickness dimensions are given in millimeters, where thickness is the distance behind the surface on the optical axis. When two surfaces of adjacent elements have the same radius and are coincident (as in a doublet or triplet), only one surface is labeled in the first or "surface" column.
For each of the four embodiments, the optical design table is followed by providing aspheric coefficients for each of the aspheric surfaces.
In addition, for each of the four embodiments, a table of variable thickness positions of the respective surfaces in each lens system optical design is provided, which indicates the positions of the respective surfaces (corresponding to entries in the surface columns of the optical design table) in the format "Px". An Effective Focal Length (EFL) and a F/No. are also provided for each position.
Each of the four embodiments of FIGS. 6A-9B will now be described briefly to identify some of their differences. The embodiment of FIGS. 6A and 6B has an effective focal length range of about 7.25mm to 900mm, which provides a zoom ratio of about 125: 1, while using three movable zoom lens groups, zoom 1, zoom 2, and zoom 3, where the focus lens groups are focused on the object space end of the lens. The zoom 3 group actually includes two groups of elements with a small amount of movement between surfaces S47 and S48 (compare fig. 6A and 6B). The embodiment of FIGS. 7A and 7B has an effective focal length range of about 7.27mm to 2088mm, provides a zoom ratio of about 287: 1, and has four movable zoom lens groups (zoom 1, 2, 3, and 4) and a focusing lens group. The embodiment of fig. 8A and 8B has an effective focal length range of about 7.27mm to 2095mm, which also provides a zoom range of about 287: 1, and has four moving zoom lens groups and a focusing lens group, which is very similar in performance to the lens embodiment of fig. 7A and 7B. Similarly, the embodiment of FIGS. 9A and 9B has an effective focal length range of about 7.27mm to 2092mm, which also provides a zoom ratio of about 287: 1, but uses only three moving zoom lens groups. Each of these four embodiments includes multiple aspheric surfaces, with the embodiments of FIGS. 8A-8B and 9A-9B having only two such surfaces, while the embodiment of FIGS. 7A-7B includes eight such surfaces, as indicated in the lens system optical design. The embodiment of fig. 9A and 9B also includes an optical image stabilizing lens element near the camera end of the lens system, similar to the lens elements included in the embodiment of fig. 10-62, which will be described below.
Detailed description of the embodiments of fig. 10-62 as noted in the paragraph entitled "brief description of the drawings" above, fig. 10-62 each refer to a single embodiment of the invention that is directly and instantly applicable to the broadcast television market, but may also be applicable to other markets and various other embodiments and modifications of the invention may be more applicable to other markets. This embodiment of the compound zoom lens system of the present invention has a focal length zoom range of about 7mm to 2100mm, thereby providing a zoom ratio of about 300: 1, which is more than three times the zoom ratio currently achievable in broadcast television zoom lens systems. Referring more specifically to the optical diagram of fig. 10, the zoom lens system ZL includes a focusing lens group FG, a front zoom group FZG, and a rear zoom group RZG. For the description of this embodiment, the stop of the lens system acts as a spacer between the "front" and "rear" of the lens. According to the terminology used in the description of the various features and embodiments of the present invention stated above, the focus lens group FG is a focus unit, the front zoom group FZG is a first optical unit and the rear zoom group RZG includes a pupil imaging unit and an image stabilization unit, and a second optical unit
The focus group FG comprises seven lens elements 1-7, of which the front lens element 1 is fixed, whereby the lens can be sealed in front by fixing and sealing the element 1 to a lens barrel (not shown). Lens element 2 includes a first focus group FG1, and lens elements 3 and 4 include a second focus group FG2, both of which are independently movable to achieve the desired focus at each focal length. The elements 5-7 of the focus group FG are fixed.
The front zoom group FZG has: a first zoom group ZG1 comprising lens elements 8-11 and a second zoom group ZG2 comprising lens elements 12-15, both zoom groups being independently movable. An iris or aperture stop "is positioned between the second zoom group ZG2 and the first group RG1 forming the front part of the rear zoom group RZG.
The first group RG1 includes lens elements 16-25 that remain stationary. An intermediate image is formed between lens elements 22 and 23 in first group RG 1. While all lens elements 16-25 of this first set RG1 remain fixed at all times, during zooming of the lens system between maximum and minimum focal lengths, the intermediate image moves between lens elements 22 and 23 along the optical axis at the longer focal length without contacting any of those elements. The next lens group of the rear zoom group RZG is a third zoom group ZG3 comprising axially movable lens elements 26-28. The next lens group in the rear zoom group RZG is a second group RG2 comprising fixed lens elements 29-33. The next elements in the rear zoom group RZG include a stabilization group SG having a radially eccentric group SG1 with lens elements 34-36 and an axially adjustable group SG2 with lens elements 37-39. The three zoom groups ZG1, ZG2, and ZG3 are independently movable along the optical axis to form a full focal length range of about 7mm to 2100 mm. Finally, FIG. 10 also illustrates two prism frames 40 and 41 (but which are not essentially part of the zoom lens system) that simulate the three conventional CCD 2/3 "detectors of a video camera in order to complete the optical map from object space to the final image.
The first or eccentric stabilization group SG1 may move radially about 0.5mm or more from the optical axis of the system in any direction in response to the sensed vibration of the lens to maintain the final image at the image plane in a stable position. Sensing of the vibration and movement of group SG1 may be accomplished in a continuous manner by any conventional means such as an accelerometer, a processor, and a motor controlled by the processor in a closed loop system. The second or axial stabilization group SG2 may be axially movable to make axial adjustments in either direction of about 1.25mm or more than 1.25mm to achieve back focus adjustment. Second stabilization group SG2 may also be moved axially forward by a greater amount to achieve an extended near focus (closefocus) at the short focal length of the lens. Light rays between first stabilizing group SG1 and second stabilizing group SG2 (i.e., between lens elements 36 and 37) are substantially collimated, whereby movement of those two groups to achieve stabilization, extend near focus, and adjust back focus does not cause any significant degradation of the final image.
The decentered stabilizing group SG1 can also be used to create special effects by causing the lens group SG1 to move radially in a shock pattern to thereby simulate shock caused by an explosion in, for example, an earthquake, moving vehicle, or war movie. Such special effects can also be produced by axially moving the lens group SG2 (which slightly defocuses the picture) in an oscillating manner. Radial movement of SG1 can also be combined with axial movement of SG2 to create different special effects.
The complete lens design of the zoom lens system ZL of the embodiment of fig. 10 to 62 is described below in a table generally entitled "tables of fig. 10 to 62". The lens system optical design table is similar to the lens design of the zoom lens of fig. 6A-9B above. A more detailed explanation of the table is provided after the table.
Tables of FIGS. 10 to 62
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S20 and S34 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S20 are: the coefficients for surface S34 are:
K＝-0.3564030 K＝0.4304790
A＝-8.06827e-07 A＝9.57697e-07
B＝-2.15109e-10 B＝1.31318e-09
C＝-6.36649e-14 C＝-1.45592e-12
D＝-3.89379e-18 D＝3.19536e-15
focal length of surface group
S2-S3 -349.648
S4-S5 -581.962
S6-S7 798.201
S10-S11 1258.758
S12-S13 672.072
S14-S15 709.848
S16-S17 646.676
S19-S20 -64.565
S21-S22 -526.211
S23-S25 -554.999
S26-S27 135.208
S28-S30 113230.702
S31-S32 240.348
S34-S35 -65.863
S36-S37 144.623
S38-S40 60.255
S41-S43 -70.987
S44-S45 58.010
S46-S47 205.873
S48-S49 52.593
S50-S51 38.634
S52-S53 -27.000
S54-S55 -34.933
S56-S57 -2495.053
S58-S59 284.851
S60-S61 167.476
S62-S64 292.466
S66-S67 97.878
S69-S70 -90.217
S71-S73 -72.295
S75-S76 61.902
S77-S79 1261.227
S80-S81 infinity
S82-S83 infinity
The lens system optical design table includes a "list" of lens specifications and numerically lists each lens "surface" in the left hand column, but also includes dummy surfaces used in the design, such as dummy surfaces S1, S8, S9, S18, S65, S74, and S84. The second column, "radius," lists the radius of the respective surface, with negative radii indicating the center of curvature to the left. The third column "thickness" lists the thickness of the lens element or the space from that surface to the next surface on the optical axis. The fourth column "glass name" lists the type of glass, and the fifth column "manufacturer" lists the manufacturer of each glass material. The fifth column, "half aperture", provides a measure of the aperture of half of each lens element.
In the left-hand column, the legend "object" refers to the object to be imaged (e.g., photographed), the legend "iris" refers to the iris or iris, and the legend "image" refers to the final image. Each of the surfaces is denoted by a number preceded by an "S" to distinguish the surface from the number that denotes the lens element set forth on the subsequent page, which includes the 39 glass lens elements described above with reference to fig. 10, and the prisms 40 and 41 of the detector.
It should be noted that each of the thickness dimensions set forth in the third column of the table listing the surfaces is an element thickness along the optical axis or an air space of the zoom lens system ZL set to the shortest focal length lens (7.39mm EFL) and focused at infinity. The "thickness" of the air space adjacent to the moving lens group will obviously vary for other focal lengths and focal distances.
For each aspheric surface, the optical design table then provides the aspheric coefficients.
Fig. 11 to 30 illustrate 20 representative positions of the zoom lens system of fig. 10. These 20 positions are listed in the following lens position table:
lens position meter
*The focal distance is measured from the first refractive surface of the zoom lens system to the object.
The focal ratio number at this position # is equal to 16.75.
Twenty (20) positions are selected as representative positions of the extreme positions of the focal length and the focal point distance and the intermediate position in order to establish representative performance of the zoom lens system ZL of fig. 10. In other words, position 1 is at a minimum paraxial focal length (wide angle) of about 7.4mm and is focused at infinity, while position 18 is focused at 2550mm (about eight feet) for the same focal length. Similarly, position 12 represents the longest paraxial focal length of about 2065mm at infinity focus, while position 15 represents focus at 2550mm at the same paraxial focal length. The paraxial EFL in the first column is at infinity focus. The f-number is at any given focus and at full aperture. The 12 different focal lengths provide a representative focal length over the full range of the zoom lens system ZL. Also, it should be noted that the actual field of view produces an apparent focal length range of substantially 7.0mm to 2100mm, i.e., a zoom ratio of about 300: 1, due to distortion of the zoom group and achievable physical over travel (physical over travel) exceeding the data in the lens system optical design set forth below, where distortion primarily affects a reduction in the minimum paraxial EFL and over travel primarily affects an increase in the maximum paraxial EFL. At a 2100mm EFL with the focus set at eight feet, the magnification is about 1.33: 1.00 (object to image size). The nominal lens design of the embodiment of FIGS. 10-62 as reflected in the lens optical design tables of FIGS. 10-62 is at 77(25 ℃, 298K) and standard atmospheric pressure (760mm Hg).
Referring now to FIGS. 11-30, the twenty positions 1-20 set forth in the above lens system optical design and the aforementioned lens position table are shown in that order. For example, fig. 11 is an optical diagram of a lens element in position 1, i.e. with an effective paraxial focal length (EFL) of 7.391mm, focused at infinity, with the first and second focus groups FG1 and FG2 closely separated, the first and second zoom groups ZG1 and ZG2 widely separated, and the third zoom group ZG3 in its forwardmost position. On the other hand, fig. 25 is an optical diagram representing a position 15 having a maximum focal length and a shortest focal distance, where both the first and second focus groups FG1 and FG2 are at their rearwardmost positions, the first and second zoom groups ZG1 and ZG2 are at closely spaced positions but spaced midway between adjacent lens groups, and the third zoom group ZG3 is at the rearwardmost position.
Fig. 31 to 34 are enlarged optical diagrams of only seven focus group FG elements 1 to 7, and respectively illustrate representative positions 1, 18, 12 and 15. It should be noted that although the lens element positions in fig. 32 and 34 are the same, representing a focal distance of 2550mm, ray tracing (raytracing) is different due to the paraxial focal length difference from a minimum of about 7.4mm in fig. 32 to a maximum of about 2065mm in fig. 34.
Fig. 35 and 36 are magnified optical diagrams illustrating the last lens element 7 of the focus group FG and the first and second zoom groups ZG1 and ZG2 at positions 1 and 12, respectively, to achieve minimum and maximum paraxial focal lengths. Similarly, fig. 37 and 38 each represent the rear zoom group RZG, respectively, with the third zoom group ZG3 being in the forwardmost and rearwardmost positions 1 and 12 representing the minimum and maximum paraxial focal length positions.
Referring now to fig. 39-58, the light ray aberrations at positions 1-20 are plotted in a conventional manner with five separate graphs, with the maximum field height at the top and the zero field height at the bottom, and for the five wavelengths listed thereon, respectively. As those skilled in the art will readily appreciate, these performance curves demonstrate that in all 20 positions, the zoom lens system performs exceptionally well for current broadcast television NTSC quality, and exceptionally well for HDTV broadcast television quality. While the graph 50 representing position 12 illustrates the wide variation in light aberrations at this focal length and focused at infinity, the performance is satisfactory because the modulation transfer function is close to the diffraction limit. Similarly, fig. 52 and 53, representing positions 14 and 15, respectively, illustrate widely varying aberrations of light rays, but are still acceptable relative to diffraction limits for these near focus and long focus positions.
Referring now to fig. 59, cam graphs of the first and second focus groups FG1 and FG2 (left and right, respectively) are depicted for a full focal length range of travel from infinity to close focus, with object space on the left side. Although the solid cam lines in fig. 59 appear to be nearly parallel, the first and second focus groups FG1 and FG2 move individually and not at exactly the same rate. The cross-hatched portions at the top and bottom of fig. 59 account for temperature variations, manufacturing tolerances, and fabrication adjustments. Similarly, fig. 60 illustrates cam graphs of three zoom groups ZG1, ZG2, and ZG3, respectively, from left to right, and it is readily appreciated that, although coordinated to consistently achieve the desired focal length throughout the range, all three zoom groups move independently. FIG. 61 is a graph of the f-number of an open stop relative to the paraxial effective focal length. Similarly, fig. 62 is a graph of full aperture full stop diameter over the full range relative to paraxial effective focal length.
Detailed description of other embodiments fig. 63 and 64 illustrate an example of another embodiment of the present invention. This embodiment of the zoom lens system is very similar to the embodiment of fig. 8A and 8B, except that a binary (diffractive) surface is provided. In particular, a binary surface is provided on the front surface (the 3 rd surface in the design) of the second lens element. The lens system optical design is set forth below in a table generally entitled "the tables of fig. 63 and 64". A more detailed explanation of the table is provided below.
Tables of FIGS. 63 and 64
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S12 and S26 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S12 are: the coefficients for surface S26 are:
K＝0.01925737 K＝-0.5574845
A＝-1.3531387e-007 A＝-1.0833227e-006
B＝-1.5274225e-011 B＝-9.1904879e-011
C＝-2.0209982e-014 C＝-1.4775967e-013
D＝5.4753514e-018 D＝6.5701323e-016
the surface profile of # binary surface S3 is subject to the following general equation:
additional phase a1p2+A2p4+A3p6+A4p8+A5p10
Wherein: a. the1、A2、A3、A4And A5Is a coefficient and p is the normalized radial coordinate at the surface.
The normalization factor is set to one and p simply becomes the radial coordinate.
A1＝-0.14123699
A2＝-8.7028052e-007
A3＝-1.2255122e-010
A4＝5.9987370e-015
A5＝-12234791e-019
The lens system optical design tables listed above are followed by the design of the binary surface 3. The binary surface 3 adds phase to the wavefront. By providing the binary surface 3, the second to fifth lens elements 2, 3, 4 and 5 in the focusing portion of the lens can be made of relatively inexpensive glass (e.g. BK7) rather than expensive optical glass with anomalous dispersion characteristics (e.g. SFPL 51). While it is advantageous to include such a binary surface 3 near the front of the lens system where the axial beam diameter is largest, those skilled in the art will readily appreciate that a binary (diffractive) surface may be provided elsewhere and that more than one such surface may be provided. Other aberration correction methods may also be advantageously used. It should be noted that this embodiment also includes two aspherical surfaces 12 and 26.
FIG. 63 shows a zoom lens system with the zoom group positioned at the longest focal length and the focus group focused at infinity. Similarly, the light ray aberration plot of fig. 64 is at infinity focus and maximum focal length. It should be noted that the use of a binary surface in this embodiment is a modification that may be used in any of the embodiments of the invention disclosed herein or future variations of the invention.
Fig. 65 and 66 illustrate an example of another embodiment of the present invention. This embodiment of the zoom lens system of the invention is very similar to the embodiment of fig. 10-62, except that a binary (diffractive) surface is provided. Specifically, a binary surface is provided on the front surface (6 th surface in the design) of the third lens element from the left. As described above with reference to fig. 10-62, the third lens element is the first (former) of the two lens elements constituting the second focus group FG2, which is axially movable to achieve focus along with the movable first focus group FG1, which includes only the second lens element. The lens system optical designs of the embodiments of fig. 65 and 66 are set forth below in a table generally entitled 'pharynx 65 and table of fig. 66'.
Tables of FIGS. 65 and 66
Optical design of lens system
Note that: maximum image diameter of 11.3mm
*The surface profiles of aspheric surfaces S17 and S31 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D coefficient
Z-the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e. the axial top point) of the surface.
The coefficients for surface S17 are: the coefficients for surface S31 are:
K＝-0.3564029 K＝0.4304792
A＝-8.6827410e-007 A＝9.5769727e-007
B＝-2.1510889e-010 B＝1.3131850e-009
C＝-6.3664850e-014 C＝-1.4559220e-012
n＝-3.8937870e-018 D＝3.1953640e-015
the surface profile of # binary surface S6 is subject to the following general equation:
additional phase a1p2+A2p4+A3p6+A4p8+A5p10
Wherein: a. the1、A2、A3、A4And A5Is a coefficient and p is the normalized radial coordinate at the surface.
The normalization factor is set to one and p simply becomes the radial coordinate.
A1＝-0.038094023
A2＝-2.7327913e-006
A3＝5.0795942e-010
A4＝-5.0245151e-014
A5＝1.5103625e-018
The lens system optical design tables listed above are followed by the design of the binary surface 6. The addition of the binary surface 6 to the basic lens system optical design of the embodiment of fig. 10-62 allows the replacement of the fluoro crown glass of lens elements 3 and 4 (third and fourth from the left in fig. 65) with less expensive glass, such as BK 7. The zoom lens system of fig. 65 and 66 has the same number of lens elements and the same number of moving groups for focusing and zooming as the embodiment of fig. 10-62, although other minor variations in the design are also made. FIG. 65 shows a zoom lens system with the zoom group positioned at the longest focal length and the focus group focused at infinity. Similarly, the light ray aberration plot of fig. 66 is at infinity focus and maximum focal length.
Fig. 67 to 70 illustrate an example of another embodiment of the present invention. This embodiment of the zoom lens system of the present invention has a zoom ratio of about 400: 1. In particular, this embodiment has a focal length zoom range of about 7.47mm (the position shown in FIG. 67) to about 2983mm (the position shown in FIG. 68). As with the embodiment of fig. 10-62, this embodiment has three moving zoom lens groups ZG1, ZG2, and ZG3, two in the front zoom lens portion and one in the rear zoom lens portion. The ray aberration plots of fig. 69 and 70 are at paraxial Effective Focal Lengths (EFLs) of 7.47mm and 2983mm, respectively, and illustrate that this embodiment performs well, taking into account the extremely wide range of focal lengths and large zoom ratios, which are similar to the performance characteristics of the embodiments of fig. 10-62. The optical diagrams of fig. 67 and 68 and the ray aberration plots of fig. 69 and 70 are plotted at infinity focus.
The lens system optical designs of fig. 67-70 are set forth below in a table generally entitled "the table of fig. 67-70". The following data in the lens system optical design are set forth in the same manner as in the previous lens system optical design, and the legend has the same meaning as in the previous lens system optical design.
Tables of FIGS. 67 to 70
Optical design of lens system
Note that: maximum image diameter of 11.0mm
*The surface profiles of aspheric surfaces S7, S10, S24, S36, S64 and S65 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D, E coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S7 are: the coefficients for surface S10 are:
K＝-0.01834396 K＝0.1385814
A＝4.6192051e-009 A＝-6.1078514e-008
B＝2.9277175e-013 B＝-1.711Q958e-012
C＝-5.3760139e-018 C＝-1.4298682e-015
D＝4.4429222e-022 D＝-7.3308393e-019
E＝0 E＝0
the coefficients for surface S24 are: the coefficients for surface S36 are:
K＝-0.1283323 K＝0.009973727
A＝-2.7157663e-007 A＝3.3999271e-008
B＝1.4568941e-010 B＝1.4717268e-010
C＝-1.4055959e-012 C＝-1.0665963e-013
D＝9.7130719e-016 D＝6.8463872e-017
E＝0 E＝0
the coefficients for surface S64 are: the coefficients for surface S65 are:
K＝-4.594951 K＝-0.2743554
A＝5.9382510e-006 A＝1.2036084e-006
B＝-4.3333569e-009 B＝3.8383867e-009
C＝-2.6412286e-013 C＝-1.5101902e-011
D＝5.0607811e-015 D＝2.3291313e-014
E＝-3.8443669e-018 E＝-1.3549754e-017
the surface profile of # binary surface S6 is subject to the following general equation:
additional phase a1p2+A2p4+A3p6+A4p8+A5p10+A6P12
Wherein: a. the1、A2、A3、A4、A5And A6Is a coefficient and p is the normalized radial coordinate at the surface.
The normalization factor is set to one and p simply becomes the radial coordinate.
A1＝-0.0183497
A2＝0.1385814
A3＝-0.1283323
A4＝0.0099737
A5＝-4.5949510
A6＝-0.2743554
Detailed description of embodiments of the folded lens fig. 71 is an optical diagram illustrating an example of yet another embodiment of the present invention incorporating one or more mirrors for folding the lens for added compactness. The example of fig. 71 is similar to the previously described embodiments, with three general zoom groups designated 50, 52 and 54. The intermediate image is located at 56. The focus group 66 is movable during focusing, but is fixed when the lens is at a constant focus. The aperture stop is located at 84. Unique to the folded zoom lens embodiment of fig. 71 is a mirror 64 located between the front zoom group 52 and the rear zoom group 54 for "folding" or bending the rays of radiation. The embodiment of fig. 71 can be used in any camera, but is particularly suitable for small cameras such as point-and-shot (point-and-shot) handheld cameras, because the folded design enables the lens to fit into a small space. Fig. 71 illustrates an SLR embodiment containing a mirror 60 and eyepiece 62 to enable the user to see the image when the mirror 60 is in the position indicated in fig. 71.
Embodiments of the present invention are particularly well suited for folding because the mirror 64 can be placed in any region within the intermediate image space 58 that does not interfere with the movement of the zoom groups 52 and 54. In contrast, conventional compact zoom lenses have lens elements that must be retracted into the camera body, which eliminates most or all air gaps within the lens and hinders insertion of the lens. In the example of FIG. 71, mirror 64 is located image-wise of intermediate image 56. However, in other embodiments, mirror 64 may be located on the object side of intermediate image 56. It should be noted that other embodiments of the invention may have multiple folds (mirrors), and the mirrors need not be oriented at 45 degrees with respect to the optical axis.
The folded lens illustrated in the example of fig. 71 achieves several useful design possibilities and advantages. As mentioned above, the folds in the lens enable the zoom lens to occupy less space. Furthermore, folding the zoom lens enables some or all of the lens elements to reside within the camera body, further improving compactness. In one embodiment, even the focusing lens group 66 may reside entirely within the camera body, protecting the lenses and making the camera more compact. In addition, folding the zoom lens enables the compact camera to achieve a zoom ratio of about 10: 1 or higher, as compared to a maximum value of about 4: 1 in a conventional compact camera. Furthermore, conventional SLR cameras require a bulky pentaprism to flip the image, and thus compact cameras typically avoid through-the-lens viewing. However, due to the intermediate image 56 and the mirrors 64 and 60 in the present invention, the final image is already properly oriented without the need for a bulky pentaprism, and through-the-lens viewing is possible even in a camera having a compact size.
The exemplary folded zoom lens of FIG. 71 provides an EFL of about 12mm to 120mm, a zoom ratio of about 10: 1, a range of f/3 to f/5 f/l ratios at full aperture, and a maximum viewing angle in object space of about 84.1 degrees to 10.3 degrees, and receives radiation in a wavelength band of at least 486nm to 588 nm. The embodiment of fig. 71 produces an image of about 12mm height by about 18mm width with a diagonal dimension of about 21.65mm, which is about half the size of an image in a conventional 35mm still photographic camera.
Fig. 72A-72D are optical diagrams illustrating the example folded zoom lens embodiment of fig. 71 in other zoom positions, with the folded lens shown in a flat (unfolded) orientation for clarity and the zoom groups in various exemplary positions. As in fig. 71, the focusing lens group 66 in the example of fig. 72A to 72D is movable so as to be focused and fixed at a constant focal point, and the mirror 64 and the eyepiece 62 are also fixed. The aperture stop is located at 84 and is movable during zooming. The example zoom lens of fig. 72A-72D actually includes eight moving zoom groups 68, 70, 72, 74, 76, 78, 80, and 82, but it should be appreciated that other embodiments of a folded zoom lens may include more or fewer zoom groups. The folded zoom lens examples of fig. 72A-72D utilize all spherical surfaces, but it is understood that other embodiments may use aspherical and/or binary (diffractive) surfaces.
Detailed description of infrared ray embodiments fig. 73A to 73C are optical diagrams of examples of Infrared Ray (IR) embodiments of the zoom lens system of the present invention, illustrating respective positions of the zoom groups. The intermediate image is located at 86. The focus group 88 is movable during focusing, but fixed at a constant focus. The final image plane is at 90 and the aperture stop is at 92. The embodiment of fig. 73A-73C can be used in low-illumination and surveillance cameras because the zoom lens system is designed for infrared wavelengths. The example of fig. 73A-73C provides an EFL of 6.68mm to 1201.21mm, a range of f/2.00 to f/5.84 f/number of focal ratios, an image diagonal of 8.0mm, a maximum viewing angle in object space of 64.5 degrees to 0.388 degrees, and a vertex length of 902.28 mm. There is-4.93% distortion at the 6.68mm focal length position and + 0.34% distortion at the 1201.2mm focal length position. This distortion increases the effective zoom ratio to 190: 1. There are a total of nine elements in the example of fig. 73A-73C, with six elements (94, 96, 98, 100, 102, and 104) in the zoom core 106 and three elements (108, 110, and 112) in the zoom relay 114. Note that "zoom kernel" as referred to herein denotes all elements from object space to the intermediate image, while "zoom relay" as referred to herein denotes all elements from the intermediate image to the final image.
The lens system optical designs of the IR embodiment of FIGS. 73A-73C are set forth below in a table generally entitled "the tables of FIGS. 73A, 73B and 73C". The following data in the lens system optical design are set forth in the same manner as in the previous lens system optical design, and the legend has the same meaning as in the previous lens system optical design.
Tables of FIG. 73A, FIG. 73B and FIG. 73C
Optical design of lens system
Note that: maximum image diameter of 8.0mm
*The surface profiles of the aspherical surfaces S2, S6, S10, S12, S13, S14, S15, S16, S17, S18 and S19 are subject to the following conventional equations：
Wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
A. B, C, D, E, F, G coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S2 are: the coefficients for surface S6 are:
K＝-0.3170663 K＝0.0000000
A＝7.1675212e-010 A＝8.8834511e-009
B＝4.6490286e-015 B＝-1.1017434e-012
C＝3.1509558e-020 C＝4.2407818e-016
D＝-3.0230207e-026 D＝-4.5843672e-020
E＝1.8711604e-043 E＝0
F＝7.2023035e-034 F＝0
G＝-1.6899714e-038 G＝0
the coefficients for surface S10 are: the coefficients for surface S12 are:
K＝0.0000000 K＝0.1424633
A＝-4.1468720e-008 A＝-1.3741884e-008
B＝-1.1864804e-012 B＝2.0574529e-010
C＝1.0375271e-016 C＝2.2356569e-013
D＝1.4819552e-020 D＝-9.2592205e-016
E＝0 E＝0
F＝0 F＝0
G＝0 G＝0
the coefficients for surface S13 are: the coefficients for surface S14 are:
K＝0.1341907 K＝0.0000000
A＝2.5853953e-007 A＝-2.3627230e-006
B＝6.3040925e-010 B＝-3.2069853e-009
C＝-8.9182471e-013 C＝1.9995538e-012
D＝-2.1087914e-016 D＝-4.1873811e-015
E＝0 E＝-4.5598387e-018
F＝0 F＝1.5355757e-021
G＝0 G＝2.7742963e-025
the coefficients for surface S15 are: the coefficients for surface S16 are:
K＝0.0000000 K＝0.0000000
A＝-1.9992749e-006 A＝-5.5264489e-007
B＝-2.7451965e-009 B＝-3.4855834e-011
C＝2.5915567e-012 C＝-1.5605019e-013
D＝-5.4747396e-015 D＝8.4346229e-016
E＝1.0432409e-018 E＝-2.6930213e-019
F＝-9.7041838e-023 F＝7.0886850e-022
G＝3.5844261e-025 G＝-4.8763355e-025
the coefficients for surface S17 are: the coefficients for surface S18 are:
K＝0.0000000 K＝0.0000000
A＝-1.9256081e-007 A＝4.5197079e-007
B＝9.7560057e-012 B＝-4.7688707e-010
C＝-3.1406997e-013 C＝-2.2771179e-013
D＝4.6996712e-016 D＝-7.3812375e-016
E＝4.3471337e-019 E＝6.1621050e-019
BU-3.7957715 e-022F-2.9782920 e-023
G＝-2.4875152e-026 G＝-2.8295343e-026
The coefficients for surface S19 are:
K＝0.0000000
A＝3.9066750e-007
B＝-2.6768710e-010
C＝-3.7378469e-013
D＝-4.0450877e-016
E＝3.9230103e-019
F＝-3.7514135e-023
G＝-8.0738327e-027
the surface profile of # binary surface S3 is subject to the following general equation:
additional phase a1p2+A2p4+A3p6+A4p8+A5p10
Wherein: a. the1、A2、A3、A4And A5Is a coefficient and p is the normalized radial coordinate at the surface.
The normalization factor is set to one and p simply becomes the radial coordinate.
A1＝-0.0085882326
A2＝-1.2587653e-008
A3＝-5.4668365e-013
A4＝8.4183658e-018
A5＝1.3774055e-022
Fig. 74 to 76 are graphs of light ray aberration curves corresponding to the positions of the zoom groups shown in fig. 73A to 73C, respectively. The light aberration plots of FIGS. 74-76 are at paraxial Effective Focal Lengths (EFL) of 6.68mm, 133.46mm, and 1201.18mm, respectively, and have a wavelength range of 8-12 microns. The optical diagrams of fig. 73A to 73C and the ray aberration graphs of fig. 74 to 76 are plotted at the infinity focus.
Detailed description of examples of 3-5 micron infrared]FIG. 77 illustrates an unfolded layout of the second exemplary IR embodiment of the zoom lens system, with lens elements and surfaces labeled. Referring to fig. 77, each lens element is labeled with a number from 120 to 138 (in pairs) and depicts the general configuration of each lens element, but the actual radius of each lens surface is set forth below in a table entitled "tables of fig. 77 and 78A-78F. The lens surfaces are labeled with the letter "S" followed by a number (from S0 to S23). Symbol for optical axis ""indicates. Each lensThe opposing surfaces of the element are indicated by separate but consecutive surface numbers, e.g., lens element 120 has lens surfaces S1 and S2, lens element 126 has lens surfaces S7 and S8, and so on. The intermediate image is located between S10 and S12. The diaphragm is located at S22. The real image surface is indicated by the numeral S23. All lens surfaces are spherical except for lens surfaces S2, S8, S9 and S21, and lens surfaces S2, S8, S9 and S21 are aspheric surfaces that are aspheric and non-flat but rotationally symmetric about the optical axis.
There are a total of 10 elements in the example of fig. 77, with five elements (120, 122, 124, 126, and 128) in the zoom core or first lens group 151 and five elements (130, 132, 134, 136, and 138) in the zoom relay or second lens group 156. The optical design of the second exemplary IR embodiment can be characterized as an NPP core followed by an NNP repeater. Note that "zoom kernel" as referred to herein denotes all elements from object space to the intermediate image, while "zoom relay" as referred to herein denotes all elements from the intermediate image to the final image.
Light rays entering the zoom lens system on the left side include an exemplary axial field beam 160 and exemplary off-axis field beams 162, 164, and 166, with the outer rays in each field beam being referred to as marginal rays and the inner rays in each field beam being referred to as chief rays. The off-axis field beam with marginal rays furthest from the optical axis is referred to as the off-axis field beam maximum marginal ray. Note that the off-axis field beam chief rays first traverse the optical axis before the intermediate image, and then traverse the optical axis again at the stop.
Before describing the detailed characteristics of the lens elements, a broad description of the lens groups and their axial positions and movements will be given for the zoom lens system of this second exemplary embodiment of the present invention, generally denoted 150. Starting from the end facing the object to be photographed (i.e., the left end in fig. 77), the first lens group 151 includes a first lens sub-group 152, a first zoom sub-group 153, a second zoom sub-group 154, and a third zoom sub-group 155. The first lens subgroup 152 is a positive-powered subgroup and includes a single lens element 120 that collects light from the object space. The first lens subgroup 152 is movable during focusing, but it is fixed at a constant focus and at a fixed distance with respect to the image plane S23. The first zoom subgroup 153 is a negative-powered subgroup and includes single lens elements 122 and 124. The second zoom subgroup 154 is a positive power subgroup and includes a single lens element 126. The third zoom subgroup 155 is a positive power subgroup and includes a single lens element 128. The second lens group 156 includes a fourth zoom subgroup 157, a fifth zoom subgroup 158, and a sixth zoom subgroup 159. The fourth zoom subgroup 157 is a negative power subgroup and comprises a single lens element 130. The fifth zoom subgroup 158 is a negative power subgroup and includes a single lens element 132. The sixth zoom subgroup 159 is a positive power subgroup and includes single lens elements 134, 136 and 138, and includes an aperture stop at S22. Although element 138 in the sixth zoom subgroup is quite thin in the example provided, in an alternative embodiment this element may be thickened to improve its manufacturability. The axially movable intermediate image is located between the third and fourth zoom subgroups 155, 157. A second exemplary IR embodiment of the zoom lens system is set forth below in the table entitled "the tables of fig. 77 and 78A-78F.
There are a total of six independent moving groups, three on the object side and three on the image side of the intermediate image. The horizontal arrows at both ends of the arrowhead in the upper portion of fig. 77 indicate that each of the zoom subgroups 153-. Although only the lens elements are physically depicted in fig. 77, it should be understood that conventional mechanical devices and mechanisms are provided for supporting the lens elements and for causing the movable group to move axially in a conventional lens housing or barrel.
Note that the spaces between the lens elements as shown in fig. 77 and fig. 78A-78F indicate that the fold mirror can be located between the zoom subgroups 154 and 155 and/or between the stop at S22 and the final image at S23 to produce a folded embodiment.
The embodiment of fig. 77 can be used in low-light and surveillance cameras because the zoom lens system is designed for IR wavelengths. The example of FIG. 77 provides an EFL of about 11.8mm to 1137.1 mm. A range of f/2.80 to f/4.00 f/number, an image diagonal of about 18.0mm, a maximum field of view angle in object space of about 0.45 to 37.36 degrees, and a vertex length from the front vertex (i.e., surface S1) to the final image (i.e., surface S22) of about 945 mm. There is 1.55% distortion at the 11.8mm focal length position and 2.14% distortion at the 1137.1mm focal length position. This distortion increases the effective zoom ratio to approximately 100: 1.
Fig. 78A to 78F are optical diagrams illustrating a second exemplary IR embodiment of a zoom lens system at various positions of a zoom group. It should be noted that lens elements 120 and 122 in fig. 78A (the leftmost two elements), although apparently touching, are actually separated by a gap. It should also be noted that in fig. 78F, all marginal rays of both the axial and off-axis field beams substantially overlap each other, which enables the front lens element 120 to be made smaller and less expensive. In particular, the maximum marginal ray height of the off-axis field beam (distance from marginal ray to the optical axis) is about 158.82mm, and the axial field beam marginal ray height is about 149.53 mm. The ratio of the distance of the maximum edge ray from the axial field beam to the distance of the axial field beam edge ray is about 1.062, which indicates that the first lens subcomponent must be manufactured to only about 6.2% of the ideal. It will be appreciated that ratios less than 1.25 are generally acceptable. Ideally, the off-axis field beam maximum marginal rays and the axial field beam marginal rays would completely overlap each other, resulting in a ratio of 1.000 and optimal size and cost for at least the first lens group.
The lens system optical design and manufacturing data for the second exemplary IR embodiment of fig. 77 and 78A-78F is set forth below in a table generally entitled "the table of fig. 77 and 78A-78F". In the tables of fig. 78A to 78F, the first column "item" designates each optical element with the same numeral or mark as used in fig. 77. The second and third columns respectively denote the "group" and "subgroup" to which the optical element (lens) belongs, with the same numerals as used in fig. 77. The fourth column "surface" is a list of the surface numbers of each of the object S0, the stop (iris) S22, the image plane S23, and the actual surface of the lens as indicated in fig. 77. The fifth column "zoom position" indicates six typical zoom positions (Z1-Z6) for the zoom subgroups 153-159 (illustrated in FIGS. 78A-78F), with variations in the distance (separation) between some of the surfaces listed in the fourth column, as described in more detail below. The sixth column, entitled legend "radius of curvature," is a list of the optical surface radius of curvature for each surface, with the minus sign (one) indicating the radius of curvature center to the left of the surface, as seen in FIG. 77, and "infinity" indicating an optically flat surface. The asterisks (@) of surfaces S2, S8, S9, and S21 indicate that these are aspheric surfaces (for which the "radius of curvature" is the base circle radius), and the formulas and coefficients for those two surfaces are set forth at asterisks as footnotes to the tables of fig. 77 and 78A-78F. The seventh column "thickness or separation" is the axial distance between the surface (fourth column) and the next surface. For example, the distance between surface S3 and surface S4 is 9.0 mm.
The eighth column of the tables of fig. 77 and 78A-78F provides the refractive material of each lens element. The last column (titled "aperture") of the tables of fig. 77 and 78A-78F provides the maximum diameter of each surface through which light passes. All maximum apertures (except for stop surface S22) were calculated assuming an image diagonal of 18mm and a relative aperture range of f/2.8 at the shortest focal length to f/4.0 at the longest focal length. The maximum apertures of the diaphragm surfaces S22 at the zoom positions Z1-Z6 are 30.170mm, respectively. 29.727mm, 28.999mm, 28.286mm, 25.654mm and 21.076 mm. The maximum relative apertures (f/l) of zoom positions Z1-Z6 are f/2.80, f/2.86, f/2.93, f/3.00, f/3.30, and f/4.00, respectively. Depending on the selection of the value of the maximum relative aperture for zoom positions Z1-Z6, very small negative air gaps may thus occur at the edges of certain elements between zoom subgroups in one or more zoom positions. Those skilled in the art will appreciate that the small negative air gap can be removed from the system by routine optimization without changing the basic design.
Tables of FIG. 77 and FIGS. 78A to 78F
*The surface profiles of aspheric surfaces S2, S8, S9 and S21 are subject to the following conventional equations:
wherein: CURV 1/(surface radius)
Y-hole height measured perpendicular to the optical axis
K. A, B, C, D, E, F coefficient
Z is the position of the surface profile for a given Y value measured along the optical axis from the extreme point (i.e., the axial vertex) of the surface.
The coefficients for surface S2 of item 1 are:
K＝-0.23909
A＝-1.20061E-09
B＝7.10421E-15
C＝-6.54538E-21
D＝1.74055E-26
E＝2.64213E-29
F＝-1.38143E-33
the coefficients for surface S8 of item 4 are:
K＝28.74452
A＝1.70772E-09
B＝6.46357E-14
C＝-6.99028E-18
D＝2.65455E-21
E＝-4.37148E-25
F＝2.27757E-29
the coefficients for surface S9 of item 5 are:
K＝-0.321348
A＝-1.84849E-07
B＝-3.24508E-11
C＝4.30816E-14
D＝-2.13370E-18
E＝-7.80714E-21
F＝1.67339E-24
the coefficients for surface S21 of item 10 are:
K＝1.125040
A＝8.42238E-07
B＝2.42138E-11
C＝4.68290E-13
D＝1.19515E-15
E＝-2.58757E-18
F＝3.72479E-21
footnotes on the tables of fig. 77 and 78A to 78F as described above*Equations for calculating the shapes of the aspherical surfaces S2, S8, S9, and S21 for the value Z are included, where CURV is the curvature at a surface extreme point, Y is the height or distance from the optical axis of a specific point on the glass surface, K is a conic coefficient, and A, B, C, D, E and F are 4 th, 6 th, 8 th, 10 th, 12 th, and 14 th order deformation coefficients, respectively. As noted above, in order to illustrate the scope and versatility of the present invention, there are six different zoom positions Z1-Z6 set forth in the data of the tables of fig. 77 and 78A-78F that provide specific data for six different positions of the six movable zoom subgroups. Zoom positions Z1-Z6 represent six positions of zoom subgroups 153-159, where zoom positions Z1 and Z6 are extreme positions and Z2, Z3, Z4, and Z5 are intermediate positions. Of course, it will be appreciated that continuous zoom may be achieved between the extreme zoom positions Z1 and Z6, and that any combination of continuous zoom may be achieved within the described zoom range of the lens system 150. In addition, continuous focusing can be achieved over the full axial range of motion of first lens group 152.
The Effective Focal Length (EFL), full field of view (FFOV), and f-number of the lens system 150 vary for different zoom positions. Referring again to fig. 78A-78F, the zoom lens system 150 is depicted with zoom groups at various zoom positions and ray tracing for those positions. FIG. 78A shows zoom position Z1, data set forth in the tables of FIG. 77 and FIGS. 78A-78F above, with an EFL of about 11.787mm, an FFOV of about 74.72, and a F-number of about 2.8. FIG. 78B shows zoom position Z2 from the tables of FIG. 77 and FIGS. 78A-78F where EFL is about 22.999mm, FFOV is about 42.74 and the F-number is about 2.9. FIG. 78C shows zoom position Z3 from the tables of FIG. 77 and FIGS. 78A-78F, where EFL is about 54.974mm, FFOV is about 18.6C, and the F-number is about 2.9. FIG. 78D shows zoom position Z4 from the tables of FIG. 77 and FIGS. 78A-78F, where EFL is about 125.359mm, FFOV is about 8.22C, and the F-number is about 3.0. FIG. 78E shows zoom position Z5 from the tables of FIG. 77 and FIGS. 78A-78F, where EFL is about 359.536mm, FFOV is about 2.86 ℃ and the F-number is about 3.3. FIG. 78F shows zoom position Z6 from the tables of FIG. 77 and FIGS. 78A-78F, where EFL is about 1137.054mm, FFOV is about 0.9C, and the F-number is about 4.0.
The specification of the separation between individual lens elements (duplicate items 120-138) and lens elements as set forth in the tables of fig. 77 and 78A-78F may be determined by using CODE V, which is commercially available from optical research Associates, incOptical design software, at 20 deg.C (68 deg.C)) Calculates the focal length of each lens element and then each set of lens elements (i.e., the first lens group 152, the first zoom subgroup 153, the second zoom subgroup 154, the third zoom subgroup 155, the fourth zoom subgroup 157, the fifth zoom subgroup 158, and the sixth zoom subgroup 159) at standard atmospheric pressure (760mm Hg), and those calculated set focal lengths are as follows:
first lens subgroup 152 (element 120) ═ 322.994 mm;
the first zoom subgroup 153 (elements 122 and 124) — 88.338 mm;
the second zoom sub-group 154 (element 126) ═ 150.688 mm;
the third zoom subgroup 155 (element 128) ═ 65.962 mm; and
the fourth zoom subgroup 157 (element 130) — 178.124 mm.
The fifth zoom sub-group 158 (element 132) — 54.620 mm.
The sixth zoom subgroup 159 (elements 134, 136 and 138) is 35.153 mm.
As mentioned above, the zoom lens system 150 is provided with one stop at the surface S22 that controls the diameter of the hole through which light rays can pass at that point to thereby cause any light rays in the zoom lens system that are radially beyond that diameter to be blocked. The diaphragm is where the physical iris is located. The iris is located inside or at one end of the sixth zoom subgroup 159 and moves with it. Note that in fig. 78A, for example, the edge ray passes through S22 with space remaining, whereas in fig. 78F, the edge ray almost touches the extreme edge of S22 as it passes through the stop. This shows that as the focal length increases, the iris at S22 must open. To maintain a constant f-number at the image, the iris must be "zoomed" or otherwise altered. In other words, the iris must be adjusted to achieve a constant aperture. A separate cam may be used to open or close the iris during zooming. In addition, it should be noted that all the lens element surface apertures set forth in the tables of fig. 77 and 78A to 78F serve as field stops at all focal points and zoom positions as depicted in fig. 78A to 78F. The size of the aperture of the iris S22 is adjusted (as described above) with respect to the maximum aperture diameter listed in the tables of fig. 77 and 78A-78F as the sixth zoom subgroup 159 moves axially, and the maximum of the sizes is given in the tables of fig. 77 and 78A-78F.
In the second exemplary IR embodiment of the zoom lens system, the sensor located at the image plane S23 is not responsive to light but to the amount of heat given off by the object under observation, and captures the difference in heat given off by the object up to a Minimum Resolvable Temperature Difference (MRTD). To this end, the sensor averages the temperature of the elements in the observed scene. The sensor ideally should not "look" at any lens structure, otherwise the temperature of the lens structure will be averaged into the scene and cause image errors. Thus, in embodiments of the present invention, the stop (i.e., the iris located at the stop) is part of the detector, and the detector including the stop is cooled to reduce electronic noise, resulting in a "cold stop".
Each of the six zoom subgroups 153-159 may be independently axially movable and their respective movements coordinated by any convenient means, such as conventional mechanical devices (e.g., cams or the like), to achieve the desired zoom function.
FIGS. 79A-79F illustrate the diffraction Modulation Transfer Functions (MTFs) of the same light rays entering the lens system at the relative field heights shown in FIGS. 78A-78F according to embodiments of the present invention. In fig. 79A to 79F, the x-axis represents spatial frequency (resolution) (in cycles per millimeter) and the y-axis represents relative modulation values (like an indication of quality). The diffraction MTF curves of fig. 79A-79F are polychromatic, using the same wavelengths and X and Y field fans, but with wavelength weights. Note that at a spatial frequency of about 15 cycles/mm, at the far right-most end of each of the curves, the diffraction MTFs of all field fans in each of the curves are concentrated with a modulation range of about 0.65 to 0.82. In general, a diffraction MTF greater than 0.50 is required, and if the diffraction MTF is greater than 80%, the lens is considered "diffraction limited" (ideal). Thus, there is no substantial degradation from the diffraction limit in the lenses of the invention. The maximum distortion in the six zoom positions of fig. 79A to 79F is about 3.5%.
Although the present invention has been fully described in connection with the embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims.
Claims (11)
1. An infrared zoom lens system for forming a final image of an object, said system having an object side and an image side and forming a first intermediate real image between said object and said final image, said system comprising:
a first lens group including at least two lens elements and located between the object and the first intermediate real image, the first lens group comprising at least one zoom subgroup that is moved to change a size of the first intermediate real image;
a second lens group including at least two lens elements and located between the first intermediate real image and the final image, at least a portion of which is moved to change a size of the final image; and
a diaphragm located between the first intermediate real image and the final image;
wherein off-axis field beam chief rays first traverse an optical axis of the infrared zoom lens system on the object side of the first intermediate real image and then traverse the optical axis again at the stop; and is
Wherein a ratio of a maximum off-axis field beam edge ray to an axial field beam edge ray at a lens surface of the first lens group adjacent to an object space at a longest focal length of the zoom lens system is less than 1.25.
2. The infrared zoom lens system of claim 1, wherein:
the stop is located between the final element surface of the second lens group and the final image.
3. The infrared zoom lens system of claim 1, wherein:
the infrared zoom lens system is capable of forming the final image from received radiation in the range of 3-5 microns.
4. The infrared zoom lens system of claim 1, wherein:
the first lens group includes five lens elements, and the second lens group includes five lens elements.
5. The infrared zoom lens system of claim 1, wherein:
the first lens group and the second lens group include: seven-bank system with one axially fixed lens sub-group and six axially movable zoom sub-groups.
6. The infrared zoom lens system of claim 1, wherein:
the first lens group includes three zoom subgroups and the second lens group includes three zoom subgroups.
7. The infrared zoom lens system of claim 1, wherein:
the first lens group includes an axially fixed lens subgroup.
8. The infrared zoom lens system of claim 1, wherein:
the lens elements include one or more germanium lens elements and one or more silicon lens elements.
9. The infrared zoom lens system of claim 1, wherein:
at least one of the lens elements includes an aspheric surface.
10. The infrared zoom lens system of claim 5, wherein:
the first lens group includes: a first lens subgroup with positive power, a first zoom subgroup with negative power, a second zoom subgroup with positive power and a third zoom subgroup with positive power, and
the second lens group includes: a fourth zoom subgroup having a negative power, a fifth zoom subgroup having a negative power, and a sixth zoom subgroup having a positive power.
11. An infrared zoom lens system for forming a final image of an object, said system having an object side and an image side and forming a first intermediate real image between said object and said final image, said system comprising:
a first lens group including five lens elements and located between the object and the first intermediate real image, the first lens group comprising at least one zoom subgroup that is moved to change a size of the first intermediate real image and having an optical design set forth in the following table, wherein the five lens elements of the first lens group are labeled in the item columns as items 120, 122, 124, 126, and 128;
a second lens group including five lens elements and located between the first intermediate real image and the final image, at least a portion of which is moved to change the size of the final image, the second lens group having an optical design set forth in the following table, wherein the five lens elements of the second lens group are labeled in the item column as items 130, 132, 134, 136 and 138; and
a diaphragm located between the first intermediate real image and the final image;
wherein a surface column in the table indicates a surface of an item, an object in the surface column is a location of the object on the side of the object, a stop in the surface column is a location of the stop, an image in the surface column is a location of the final image, a radius of curvature column in the table states a radius of the corresponding surface, a thickness or separation column in the table states a distance of one surface to a next surface, a refractive material column in the table indicates a material between the corresponding surface and the next surface, and an aperture column in the table states a maximum diameter of a ray passing through the corresponding surface;
wherein off-axis field beam chief rays first traverse an optical axis of the infrared zoom lens system on the object side of the first intermediate real image and then traverse the optical axis again at the stop; and is
Wherein a ratio of a maximum off-axis field beam edge ray to an axial field beam edge ray at a lens surface of the first lens group adjacent to an object space at a longest focal length of the zoom lens system is less than 1.25,
where the asterisks of the surfaces S2, S8, S9 and S21 indicate that these are aspherical surfaces, where the radius of curvature is the base circle radius.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11/192,778 US7224535B2 (en) | 2005-07-29 | 2005-07-29 | Zoom lens system |
| US11/192,778 | 2005-07-29 | ||
| PCT/US2006/028797 WO2007016075A2 (en) | 2005-07-29 | 2006-07-24 | Zoom lens system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| HK1125180A1 HK1125180A1 (en) | 2009-07-31 |
| HK1125180B true HK1125180B (en) | 2011-03-25 |
Family
ID=
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1910881B1 (en) | Zoom lens system | |
| EP1523691B1 (en) | Zoom lens system with ultra high zoom ratio | |
| KR101280742B1 (en) | Wide-range, wide-angle compound zoom with simplified zooming structure | |
| US8773766B2 (en) | Liquid optics with folds lens and imaging apparatus | |
| CA2577629C (en) | Wide-range, wide-angle, rotatable compound zoom | |
| US9250422B2 (en) | Zoom lens with forward-located aperture stop | |
| CN110320652A (en) | Zoom lens and photographic device | |
| US6122111A (en) | High performance zoom lens system | |
| US7436601B2 (en) | Two-group zoom lens and an electronic imaging apparatus having it | |
| JPH09197267A (en) | Infrared zoom lens | |
| HK1125180B (en) | Zoom lens system |