CN112799275B - Focusing method and focusing system of ultra-short-focus projection lens and projector - Google Patents
Focusing method and focusing system of ultra-short-focus projection lens and projector Download PDFInfo
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- CN112799275B CN112799275B CN201911113172.9A CN201911113172A CN112799275B CN 112799275 B CN112799275 B CN 112799275B CN 201911113172 A CN201911113172 A CN 201911113172A CN 112799275 B CN112799275 B CN 112799275B
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/53—Means for automatic focusing, e.g. to compensate thermal effects
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/28—Systems for automatic generation of focusing signals
- G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
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Abstract
The invention discloses a focusing method and a focusing system of an ultra-short-focus projection lens and a projector, relates to the technical field of projection, and is used for solving the problem of low focusing efficiency of the existing focusing method of the ultra-short-focus projection lens. The ultrashort-focus projection lens focusing method comprises the following steps: receiving a focusing instruction; acquiring a current projection distance between the projection equipment and a projection screen; comparing the current projection distance with a plurality of preset projection distances, wherein the plurality of preset projection distances correspond to a plurality of first preset position ranges one by one, and a second preset position range exists between two adjacent first preset position ranges; if the current projection distance is equal to one preset projection distance in the plurality of preset projection distances, controlling the movable mirror group to move to a first preset position range; and if the current projection distance is between two adjacent preset projection distances in the plurality of preset projection distances, controlling the movable mirror group to move to a second preset position range. The invention is used for focusing the movable lens group.
Description
Technical Field
The invention relates to the technical field of projection correlation, in particular to a focusing method and a focusing system of an ultra-short-focus projection lens and a projector.
Background
A projection system is a display system consisting of a projection device, a projection screen, an image controller and other auxiliary devices. A projector is a device that can project an image or video on a projection screen by enlarging the image through a lens assembly in the projection device.
At present, with the advent of ultra-short focus projectors, since the ultra-short focus projector has a very short transmittance, i.e., a ratio of a projection distance between the projector and a projection screen to a screen size, the projector can project a picture onto a large screen (70 inches or more) from a few inches away from the surface of the projection screen, and the situation in which the projector moves in front of the projector to block the picture on the projection screen does not exist. Meanwhile, in order to ensure that a projection image or a projection picture on a projection screen is clear, the position of a movable lens group in an ultra-short-focus projection lens needs to be adjusted, and a focusing method of a projection device in the prior art comprises two modes of manual focusing and automatic focusing.
Manual focusing: the manual focusing is realized by manually adjusting the position of the movable lens group to ensure that the display effect of a projected image on a projection screen is good, but the focusing process of the manual focusing is time-consuming, and the focusing quality is determined by human eyes macroscopically, so that the focusing efficiency and the focusing accuracy of the manual focusing are low.
Automatic focusing: in the initial stage of automatic focusing, the movable mirror group needs to be debugged in one direction for a preset distance, and then whether the moving direction of the current movable mirror group is correct or not is judged according to the display effect of the projected image on the projection screen. If the movable mirror group is firstly debugged for a preset distance in one direction, the display effect of a projected image on the projection screen becomes good, and the moving direction of the current movable mirror group is correct; if the movable mirror group tries to adjust a preset distance in one direction, the display effect of a projected image on the projection screen is deteriorated, and the moving direction of the current movable mirror group is incorrect. The automatic focusing method has the following problems: first, the automatic focusing method needs to first determine whether the moving direction of the movable lens group is correct. Secondly, in the automatic focusing method, when the movable lens group moves a preset distance each time and moves a preset distance each time, whether the display effect of the projection image on the projection screen meets the requirement needs to be judged manually or mechanically, and the focusing process of the movable lens group is time-consuming and the focusing efficiency is low.
Disclosure of Invention
The invention provides a focusing method, a focusing system and a projector of an ultra-short-focus projection lens, which are used for solving the problem of low focusing efficiency of the focusing method of the ultra-short-focus projection lens in the prior art.
In order to achieve the above object, in a first aspect, an embodiment of the present invention provides a method for focusing an ultra-short-focus projection lens, where the ultra-short-focus projection lens includes: a fixed lens group and a movable lens group; a driving motor to drive the movable mirror group to move in a direction of an optical axis; the ultrashort-focus projection lens focusing method comprises the following steps: receiving a focusing instruction; acquiring a current projection distance between the projection equipment and the projection screen; comparing the current projection distance with a plurality of preset projection distances, wherein the plurality of preset projection distances correspond to a plurality of first preset position ranges of the movable mirror group one by one, a second preset position range exists between two adjacent first preset position ranges, and two end point values of the second preset position range are respectively two end point values which are close to each other in two adjacent first preset position ranges corresponding to the two adjacent preset projection distances; if the current projection distance is equal to one of the preset projection distances, controlling the driving motor to drive the movable mirror group to move to the first preset position range; and if the current projection distance is located between two adjacent preset projection distances in the plurality of preset projection distances, controlling the driving motor to drive the movable mirror group to move to the second preset position range.
In a second aspect, the invention further provides an ultra-short-focus projector, which adopts the focusing method of the ultra-short-focus projection lens.
In a third aspect, the present invention further provides an ultra-short-focus projection lens focusing system for adjusting a distance between a movable lens group in a projection device and a projection screen, including: the distance measuring device is used for measuring the projection distance between the projection equipment and the projection screen; the driving motor is connected with the movable mirror group and drives the movable mirror group to move along an optical axis; a controller, the controller with range unit, the even electricity of driving motor is connected, the controller includes: the storage module is used for presetting a focusing parameter table of the corresponding relation between the projection distance and the preset position range; and the control module is used for controlling the driving motor to drive the movable mirror group to move to the preset position range according to the projection distance obtained by the distance measuring device and the focusing parameter table stored by the storage module.
In a fourth aspect, the invention further provides an ultra-short focus projector, which includes the ultra-short focus projection lens focusing system.
The ultrashort-focus projection lens focusing method provided by the embodiment of the invention is characterized in that after the ultrashort-focus projection lens receives a focusing instruction, the display effect of a projection image on a current projection screen is poor, the projection distance between the current projection device and the projection screen is obtained, the current projection distance is compared with a plurality of preset projection distances, the preset projection distances correspond to a plurality of first preset position ranges of a movable lens group one by one, if the current projection distance is equal to one of the preset projection distances, a target moving position range of the movable lens group can be directly determined as the first preset position range by one of the preset projection distances which is equal to the current projection distance, and then a driving motor is controlled to drive the movable lens group to move to the first preset position range; if the current projection distance is located between two adjacent preset projection distances among the preset projection distances, that is, the current projection distance is different from all the preset projection distances among the preset projection distances, it indicates that the target moving position range of the movable mirror group is located between two adjacent first preset position ranges corresponding to the two adjacent preset projection distances, that is, the target moving position range is moved to the second preset position range, and then the driving motor is controlled to drive the movable mirror group to move to the second preset position range, so that the display effect of the current projection image on the projection screen is improved. Compared with the prior art, the ultrashort-focus projection lens focusing method provided by the embodiment of the invention can move the movable lens group to the position near the focusing position corresponding to the current projection distance without moving the movable lens group for multiple times, so that the focusing time of the movable lens group is shortened, and the focusing efficiency of the movable lens group is improved.
Meanwhile, the ultrashort-focus projector provided by the embodiment of the invention adopts the ultrashort-focus projection lens focusing method, so that the time required by the focusing process of the ultrashort-focus projector adopting the ultrashort-focus projection lens focusing method is short, and the focusing efficiency is high.
The ultrashort-focus projection lens focusing system provided by the embodiment of the invention stores a focusing parameter table of the corresponding relation between the preset projection distance and the preset position range in a storage module of a controller in advance. And then when the position of the movable mirror group needs to be adjusted, the controller is used for acquiring the projection distance between the projection equipment and the projection screen, which is measured by the distance measuring device, searching a preset position range corresponding to the preset horizontal distance corresponding to the current projection distance from a focusing parameter table in the storage module, sending a control instruction to the driving motor by the controller, and controlling the movable mirror group to move to the preset position range after the driving motor receives the control instruction. Compared with the prior art, the embodiment of the invention can move the movable mirror group to the position near the focusing position corresponding to the current projection distance by moving the movable mirror group once; meanwhile, as the focusing parameter table is stored in the storage module in advance, the movable lens group does not move step by step in the process of moving to the preset position range, so that the focusing time of the movable lens group is shortened, and the focusing efficiency of the movable lens group is improved.
Meanwhile, the ultrashort-focus projector provided by the embodiment of the invention adopts the ultrashort-focus projection lens focusing system, so that the time required by the focusing process of the ultrashort-focus projector adopting the ultrashort-focus projection lens focusing system is short, and the focusing efficiency is high.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flowchart illustrating a method for focusing an ultra-short-focus projection lens according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a first operating mode according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a second operating mode in an embodiment of the present invention;
FIG. 4 is a schematic diagram of an ultra-short-focus projection system according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of an ultra-short focus projection lens assembly according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of an ultra-short focus projection lens focusing system in an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
With the development of display technology, people have higher and higher requirements on the display effect of images or videos projected on a projection screen. Therefore, when the projection distance between the projection device and the projection screen is changed or the display magnification is changed, the position of the movable mirror group in the projection device needs to be adjusted, otherwise, the image or the video on the projection screen becomes blurred, and the user cannot watch the projected image or the projected video, so that the user experience of the projection device in the use process is reduced. Therefore, the invention provides an automatic focusing method which is used for focusing a movable lens group in a lens assembly.
Referring to fig. 1, an embodiment of the present invention provides a method for focusing an ultra-short-focus projection lens, where the ultra-short-focus projection lens includes: a fixed lens group and a movable lens group; the driving motor drives the movable mirror group to move along the direction of the optical axis; the ultrashort-focus projection lens focusing method comprises the following steps: receiving a focusing instruction; acquiring a current projection distance L (i) between the projection equipment and a projection screen; comparing the current projection distance L (i) with a plurality of preset projection distances L '(j), wherein the plurality of preset projection distances L' (j) correspond to a plurality of first preset position ranges of the movable mirror group one by one, a second preset position range exists between two adjacent first preset position ranges, and two end point values of the second preset position range are respectively two end point values which are close to each other in two adjacent first preset position ranges corresponding to two adjacent preset projection distances; if the current projection distance L (i) is equal to one of the preset projection distances, controlling the driving motor to drive the movable mirror group to move to the first preset position range; and if the current projection distance L (i) is positioned between two adjacent preset projection distances in the plurality of preset projection distances, controlling the driving motor to drive the movable mirror group to move to a second preset position range. The operation of controlling the driving motor to move the movable mirror group can be executed through a control module which is arranged in a main controller of the ultra-short-focus projection lens and is used for controlling the driving motor, and can also be executed through a sub-controller which is specially arranged in the ultra-short-focus projection lens and is used for controlling the driving motor; the controller comprises a storage module, the storage module is used for storing a plurality of first preset position ranges which are in one-to-one correspondence with a plurality of preset projection distances L' (j), the ultra-short focus projection lens comprises a counting module, and the counting module is electrically connected with the controller and is used for recording focusing times of the movable lens group.
After the ultra-short-focus projection lens receives a focusing instruction, that is, after the ultra-short-focus projection lens receives the focusing instruction, it indicates that the display effect of a projection image on a current projection screen is poor, a projection distance between the current projection device and the projection screen is obtained, the current projection distance L (i) is compared with a plurality of preset projection distances L '(j), the preset projection distances L' (j) correspond to a plurality of first preset position ranges of a movable lens group one by one, if the current projection distance L (i) is equal to one of the preset projection distances L '(j), a target moving position range of the movable lens group can be directly determined as the first preset position range by one of the preset projection distances L' (j) which is equal to the current projection distance L (i), and then a driving motor is controlled to drive the movable lens group to move to the first preset position range; if the current projection distance L (i) is located between two adjacent preset projection distances of the preset projection distances L '(j), that is, the current projection distance L (i) is different from all the preset projection distances of the preset projection distances L' (j), it indicates that the target moving position range of the movable mirror group is located between two adjacent first preset position ranges corresponding to the two adjacent preset projection distances, that is, the target moving position range is moved to a second preset position range, and then the driving motor is controlled to drive the movable mirror group to move to the second preset position range, thereby improving the display effect of the current projection image on the projection screen. Compared with the prior art, the ultrashort-focus projection lens focusing method provided by the embodiment of the invention can move the movable lens group to the position near the focusing position corresponding to the current projection distance L (i) without moving the movable lens group for multiple times, so that the focusing time of the movable lens group is shortened, and the focusing efficiency of the movable lens group is improved.
It should be noted that: the second preset position range is a position range between every two adjacent first preset position ranges, that is, the second preset position range is located between the first preset position range X '(j) and the first preset position range X' (j + 1).
Based on the above embodiment, since the moving the movable mirror group to the first predetermined position is only to move the movable mirror group to the vicinity of the focusing position corresponding to the current projection distance L (i), after the moving, the movable mirror group may not be at the optimal focusing position, and thus the controlling the driving motor to drive the movable mirror group to move to the first predetermined position range further includes: controlling a driving motor to drive the movable mirror group to move within a first preset position range by a preset distance d; acquiring a projection image of a current projection screen; obtaining a current definition value D (t) of the projected image according to the projected image; if the current definition value D (t) is equal to the preset definition value D b Controlling the driving motor to stop; if the current definition value D (t) is less than the preset definition value D b And returning to the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by the preset distance. The projection system further comprises an image acquisition device, wherein the image acquisition device is used for acquiring a projection image on the projection screen and is electrically connected with the main controller or the sub-controller. The storage module is also used for storing a built-in graphic card and a preset definition value D b The above-mentioned predetermined sharpness value D b The optimal definition value of the built-in graphic card.
Similarly, the driving motor is controlled therebyAfter driving the movable mirror group to move to the second preset position range, the method further comprises: controlling the driving motor to drive the movable mirror group to move within a second preset position range by a preset distance d; acquiring a projection image of a current projection screen; obtaining a current definition value D (t) of the projected image according to the projected image; if the current definition value D (t) is equal to the preset definition value D b Controlling the driving motor to stop; if the current definition value D (t) is less than the preset definition value D b And returning to the step of controlling the driving motor to drive the movable mirror group to move within the second preset position range by the preset distance.
Further, the receiving the focusing instruction specifically includes: acquiring a projection image of a current projection screen; processing the projected image to obtain a current definition value D (t) of the projected image; if the current definition value D (t) is equal to the preset definition value D b Controlling the driving motor to stop; if the current definition value D (t) is less than the preset definition value D b Then the step of receiving a focusing instruction is returned. Therefore, if a focusing instruction is received, it is indicated that the movable mirror group needs to be focused, the controller controls the projection equipment to project a projection image onto the projection screen, controls the image acquisition device to acquire the projection image on the projection screen, and processes the projection image to obtain a definition value D (t) of the projection image; the controller combines the current definition value D (t) with the preset definition value D b Comparing if the definition value D (t) is equal to the preset definition value D b When the image is projected on the projection screen, the definition value of the projected image is better, the movable lens group does not need to be focused, and the driving motor is controlled to stop; if the definition value D (t) is less than the preset definition value D b If the display effect of the projected image on the projection screen is not good, the movable lens group needs to be focused, and the step of receiving the focusing instruction is returned.
In addition, through judging the definition value of the projected image on the projection screen, the situation that the movable mirror group does not need focusing can be avoided, the controller controls the movable mirror group to execute focusing operation, unnecessary focusing operation of the movable mirror group is reduced, and due to the definition value of the projected image on the projection screen, the display effect of the current projected image can be intuitively reflected, whether the movable mirror group needs focusing is judged through the definition value, and the reliability is high.
Optionally, after comparing the current projection distance L (i) with a plurality of preset projection distances L' (j), before controlling the driving motor to drive the movable mirror group to move to the first preset position range, the method for focusing an ultra-short focus projection lens further includes: acquiring a current position X (t) of the movable mirror group; if the current projection distance L (i) is equal to one preset projection distance of a plurality of preset projection distances L' (j), and the current position X (t) of the movable mirror group is located outside the first preset position range, controlling a driving motor to drive the movable mirror group to move to an end position, closest to the current position X (t) of the movable mirror group, in the first preset position range, completing a coarse adjustment step, then returning to the step of receiving a focusing instruction, and obtaining a projection image of the current projection screen again; obtaining a current definition value D (t) of the projected image according to the projected image; if the current definition value D (t) is equal to the preset definition value D b The movable lens group does not need to be focused, and the driving motor is controlled to stop; if the current definition value D (t) is less than the preset definition value D b It indicates that the movable lens group still needs to be adjusted to the next step, i.e. the fine adjustment step.
Similarly, after comparing the current projection distance L (i) with the plurality of preset projection distances L' (j), and before controlling the driving motor to drive the movable mirror group to move to the second preset position range, the method for focusing the ultra-short focus projection lens further includes: acquiring a current position X (t) of the movable mirror group; and if the current projection distance L (i) is positioned between two adjacent preset projection distances in the plurality of preset projection distances L' (j) and the current position X (t) of the movable mirror group is positioned outside the second preset position range, controlling the driving motor to drive the movable mirror group to move to an end position which is closest to the current position X (t) of the movable mirror group in the second preset position range, and returning to the step of receiving the focusing instruction.
The following specific description is made by combining two working conditions to respectively specify that the current position X (t) of the movable mirror group is located outside the first preset position range and the current position X (t) of the movable mirror group is located outside the second preset position range:
first operating mode
In the above ultra-short-focus projection lens focusing method, if the current projection distance L (i) is equal to one of the preset projection distances L' (j), and the current position of the movable lens group is located outside the first preset position range, controlling the driving motor to drive the movable lens group to move to an end position in the first preset position range that is closest to the current position of the movable lens group specifically includes:
when X (t) < X 1 '(j)，X 1 'j' is the first end point position of the first preset position range, the driving motor is controlled to drive the movable mirror group to move to X 1 ' (j) and returns to the step of receiving the focusing instruction.
When X (t) > X 2 '(j)，X 2 'j' is the second end point position of the first preset position range, the driving motor is controlled to drive the movable mirror group to move to X 2 ' (j) and returns to the step of receiving the focusing instruction. Wherein, X 1 '(j)＜X 2 '(j)。
Referring to fig. 2, when exactly one preset projection distance is equal to the current projection distance L (i) in the preset projection distances L' (j), the target position range corresponding to the current projection distance L (i) is a first preset position range, where a first endpoint position X in the first preset position range is 1 ' (j) is the left end position in FIG. 2, the second end position X in the first predetermined position range 2 ' (j) is the position of the right endpoint, X, in FIG. 2 1 '(j)＜X 2 '(j)。
When X (t) < X 1 ' (j) indicating that the current position X (t) of the movable mirror group is located at the left end position X 1 ' (j) left side, at this time the movable mirror group and the left end point position X 1 'j' is shorter, the controller controls the movable mirror group to move to the left end point position X in the first preset position range 1 ' (j) takes a short time, so that the time for moving the movable mirror group to the first preset position range can be further shortened. When the controller completes the moving operation of the movable lens group, namely the coarse adjustment step, then the controller returns to the stepAnd receiving a focusing instruction, and determining whether the movable lens group still needs to be subjected to the next adjusting step, namely the fine adjusting step.
Similarly, when X (t) > X 2 ' (j), it indicates that the current position X (t) of the movable mirror group is located at the left end position X 2 ' (j) right side, movable lens group and right end point position X 2 'j' is shorter, the controller controls the movable mirror group to move to the right end point position X in the first preset position range 2 ' (j), and then returns to the step of receiving the focusing instruction.
Based on the above embodiment, the driving motor is controlled to drive the movable mirror group to move to the endpoint value of the first preset range, and then the step of receiving the focusing instruction is returned, whether the movable mirror group needs to be adjusted continuously is judged, and if the movable mirror group still needs to be adjusted is judged, the fine adjustment step is performed.
When X (t) < X 1 '(j)，X 1 (j) when the position is the first end point of the first preset position range, controlling the driving motor to keep the current rotating direction unchanged, and driving the movable mirror group to move a preset distance d in the first preset position range; the current rotation direction refers to the driving motor driving the movable lens group to move to the first end point position X 1 ' (j) the rotational direction of the drive motor.
When X (t) > X 2 '(j)，X 2 ' (j) when the position is the second end point of the first preset position range, controlling the driving motor to keep the current rotating direction unchanged, and driving the movable mirror group to move a preset distance d in the first preset position range; at this time, the current rotation direction refers to the driving motor driving the movable lens set to move to the second endpoint position X 2 ' (j) the rotational direction of the drive motor.
Further, after comparing the current projection distance L (i) with a plurality of preset projection distances L' (j), before controlling the driving motor to drive the movable mirror group to move to the first preset position range, the method for focusing an ultra-short focus projection lens further includes: acquiring a current position X (t) of the movable mirror group; if the current projection distance L (i) is equal to a plurality of preset projection distances L'j' and when the preset projection distance is equal and the current position X (t) of the movable mirror group is within the first preset position range, the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by the preset distance is returned. If the current projection distance L (i) is equal to one of the predetermined projection distances L' (j) and the current position X (t) of the movable mirror group is within the first predetermined position range, that is, X 1 '(j)＜X(t)＜X 2 ' (j) the movable mirror group goes directly to the fine adjustment step without performing coarse adjustment. Firstly, through the specific step of receiving a focusing instruction, whether the movable lens group needs to be subjected to fine adjustment is judged, and if the movable lens group needs to be continuously adjusted, the fine adjustment step is carried out. Secondly, if the movable lens group needs to be finely adjusted, since the current movable lens group is located in the first preset position range, before entering the fine adjustment step, the moving direction of the movable lens group needs to be determined through the judgment step, and at this time, the controller controls the movable lens group to move within the first preset range by the preset distance d.
Further, in the ultra-short focus projection lens focusing method in the embodiment of the present invention, if the current sharpness value D (t) is smaller than the preset sharpness value D b Then, the step of controlling the driving motor to drive the movable lens group to move the preset distance in the first preset position range includes (determining step): if the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is greater than the previous definition value D (t-1), controlling the current rotating direction of the driving motor to keep the previous rotating direction, and returning to the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by the preset distance D; if the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is smaller than the previous definition value D (t-1), the current rotating direction of the driving motor is changed to be the opposite direction of the previous rotating direction, and the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by the preset distance D is returned. If the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is greater than the last definition value D (t-1), the tableAfter the movable mirror group moves the preset distance d in the above steps, the definition value of the projection image on the projection screen is increased, that is, the moving direction of the movable mirror group is correct, and at this time, the current rotating direction of the driving motor is the last rotating direction. If the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is smaller than the previous definition value D (t-1), it indicates that the definition value of the projection image on the projection screen is increasingly bad after the movable mirror group moves the preset distance D in the above step, i.e. the moving direction of the movable mirror group in the above step is wrong, and at this time, the current rotating direction of the driving motor needs to be changed to be the opposite direction of the previous rotating direction, so as to change the moving direction of the movable mirror group.
Second operating mode
Similarly, in the above ultra-short-focus projection lens focusing method, if the current projection distance L (i) is located between two adjacent preset projection distances among the plurality of preset projection distances L' (j), and the current position X (t) of the movable mirror group is located outside the second preset position range, controlling the driving motor to drive the movable mirror group to move to the end position closest to the current position X (t) of the movable mirror group in the second preset position range specifically includes:
when X (t) < X 1 '(j)，X 1 'j' is the first end point position of the second preset position range, the driving motor is controlled to drive the movable mirror group to move to X 1 ' (j) and returns to the step of receiving the focusing instruction.
When X (t) > X 2 '(j)，X 2 'j' is the second end point position of the second preset position range, the driving motor is controlled to drive the movable mirror group to move to X 2 ' (j) and returns to the step of receiving the focusing instruction. Wherein, X 1 '(j)＜X 2 '(j)。
Referring to fig. 3, when the current projection distance L (i) is located between two adjacent preset projection distances of the preset projection distances L '(j) (any one of the preset projection distances L' (j) is not equal to the current projection distance L (i)), the target position range corresponding to the current projection distance L (i) is the target position range corresponding to the current projection distance L (i)A second predetermined position range, wherein the first endpoint position X in the second predetermined position range 1 ' (j) is the left end position in FIG. 3, the second end position X in the second predetermined position range 2 ' (j) is the position of the right endpoint, X, in FIG. 3 1 '(j)＜X 2 '(j)。
When X (t) < X 1 ' (j) indicating that the current position X (t) of the movable mirror group is located at the left end position X 1 ' (j) left side, at this time the movable mirror group and the left end point position X 1 'j' is shorter, the controller controls the movable mirror group to move to the left end point position X in the second preset position range 1 ' (j) takes a short time, so that the time for moving the movable mirror group to the second preset position range can be further shortened. When the controller finishes the moving operation of the movable lens group, namely the rough adjusting step is finished, the controller returns to the step of receiving the focusing instruction, and determines whether the movable lens group needs to continue to the next adjusting step again, namely the fine adjusting step.
When X (t) > X 2 ' (j), it indicates that the current position X (t) of the movable mirror group is located at the left end position X 2 ' (j) right side, movable mirror group and right end point position X 2 'j' distance is shorter, the controller controls the movable mirror group to move to the right end point position X in the second preset position range 2 ' (j), and then returns to the step of receiving the focusing instruction.
Based on the above embodiment, the driving motor is controlled to drive the movable mirror group to move to the endpoint value of the second preset range, and then the step of receiving the focusing instruction is returned, whether the movable mirror group needs to be adjusted continuously is judged, and if the movable mirror group still needs to be adjusted is judged, the fine adjustment step is performed.
When X (t) < X 1 '(j)，X 1 ' (j) when the position is the first end point of a second preset position range, controlling a driving motor to keep the current rotating direction unchanged, and driving the movable mirror group to move a preset distance d in the second preset position range; at this time, the current rotation direction refers to the driving motor driving the movable mirror group to move to the first endpoint position X 1 ' (j) time driveThe direction of rotation of the motor.
When X (t) > X 2 '(j)，X 2 ' (j) when the second endpoint position of a second preset position range is adopted, controlling a driving motor to keep the current rotating direction unchanged, and driving the movable mirror group to move a preset distance d in the second preset position range; at this time, the current rotation direction refers to the driving motor driving the movable lens set to move to the second endpoint position X 2 ' (j) the rotational direction of the drive motor.
Further, after comparing the current projection distance L (i) with a plurality of preset projection distances L' (j), before controlling the driving motor to drive the movable mirror group to move to the second preset position range, the method for focusing an ultra-short focus projection lens further includes: acquiring a current position X (t) of the movable mirror group; and if the current projection distance L (i) is located between two adjacent preset projection distances in the plurality of preset projection distances L' (j) and the current position X (t) of the movable mirror group is located in a second preset position range, returning to the step of controlling the driving motor to drive the movable mirror group to move within the second preset position range by a preset distance. If the current projection distance L (i) is located between two adjacent preset projection distances of the plurality of preset projection distances L' (j) and the current position X (t) of the movable mirror group is located in the second preset position range, that is, X 1 '(j)＜X(t)＜X 2 ' (j) the movable mirror group goes directly to the fine adjustment step without performing coarse adjustment. Firstly, through the specific step of receiving a focusing instruction, whether the movable lens group needs to be subjected to fine adjustment is judged, and if the movable lens group needs to be continuously adjusted, the fine adjustment step is carried out. Secondly, if the movable lens group needs to be finely adjusted, since the movable lens group is currently located in a second preset position range, before entering the fine adjustment step, the moving direction of the movable lens group needs to be determined through the judgment step, and at this time, the controller controls the movable lens group to move within the second preset range by a preset distance d.
Further, in the ultrashort-focus projection lens focusing method in the embodiment of the present invention, if the current sharpness value D (t) is smaller than the preset sharpness value D b Then the driving motor is controlled to drive the movable lens set at the second predetermined positionThe step of moving the preset interval within the range specifically includes (judging step): if the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is greater than the previous definition value D (t-1), controlling the current rotating direction of the driving motor to keep the previous rotating direction, and returning to the step of controlling the driving motor to drive the movable mirror group to move within the second preset position range by the preset distance D; if the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is smaller than the previous definition value D (t-1), the current rotating direction of the driving motor is changed to be the opposite direction of the previous rotating direction, and the step of controlling the driving motor to drive the movable mirror group to move within the second preset position range by the preset distance D is returned. If the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is greater than the previous definition value D (t-1), the definition value of the projection image on the projection screen is increased after the movable mirror group moves the preset distance D in the previous step, that is, the moving direction of the movable mirror group is correct, and at the moment, the current rotating direction of the driving motor keeps the previous rotating direction. If the current definition value D (t) is less than the preset definition value D b And if the current definition value D (t) is smaller than the previous definition value D (t-1), it indicates that the definition value of the projection image on the projection screen is increasingly bad after the movable mirror group moves by the preset distance D in the above step, i.e. the moving direction of the movable mirror group in the above step is wrong, and at this time, the current rotating direction of the driving motor needs to be changed to be the opposite direction of the previous rotating direction, so as to change the moving direction of the movable mirror group.
It should be noted that: when the movable lens group is roughly adjusted, that is, when the target position range of the movable lens group is a first preset position range and moves from the outside of the first preset range to the endpoint value of the first preset range, the moving speed of the movable lens group is V 1 . When the movable lens group is fine-tuned, i.e. moves within the first predetermined position range by the predetermined distance d, the moving speed of the movable lens group is V 2 And V is 1 ＞V 2 . Thereby, the movable lens group enters the first lens groupThe movable lens group is quickly moved in the preset position range and is adjusted at a low speed after entering the first preset position range, so that the time spent by the movable lens group in the focusing process is further shortened, and the focusing efficiency of the movable lens group is improved.
Similarly, when the movable lens group is roughly adjusted, that is, when the target position range of the movable lens group is the second preset position range and moves from outside the second preset range to the endpoint value of the second preset range, the moving speed of the movable lens group is V 1 . When the movable lens group is fine-tuned, i.e. moves within the second predetermined position range by the predetermined distance d, the moving speed of the movable lens group is V 2 And V is 1 ＞V 2 . Therefore, the movable lens group can move quickly when entering the second preset position range, and can be adjusted at a low speed after entering the second preset position range, so that the time spent by the movable lens group in the focusing process is further shortened, and the focusing efficiency of the movable lens group is improved.
The embodiment of the invention also provides an ultra-short-focus projector, which adopts the ultra-short-focus projection lens focusing method, so that the time required by the focusing process of the ultra-short-focus projector adopting the ultra-short-focus projection lens focusing method is shorter, and the focusing efficiency is higher.
One way to achieve the ultra-short focus projection is a reflective short focus projection, i.e. an image is projected onto a reflective surface of a curved mirror through a projection lens and is reflected onto a projection screen through the curved mirror, the reflective short focus projection system generally comprises a light source, a light valve 1, a TIR (Total Internal Reflection) prism 2, a vibrating mirror 3 and an ultra-short focus lens assembly 4, and the ultra-short focus lens assembly 4 comprises a curved mirror 41 and an ultra-short focus projection lens 42. The light valve 1 is used for outputting an image beam emitted by the light source, the image beam is reflected to the galvanometer 3 through the TIR prism 2, and then is transmitted to the ultra-short focus projection lens 42 through the galvanometer 3, and the image beam is polymerized to a certain extent after passing through the ultra-short focus projection lens 42, thereby completing the first imaging. The image beam after the first imaging enters the curved reflector 41, and the curved reflector 41 reflects the image beam onto the projection screen, so that a large-size projection image can be displayed on the projection screen, and the second imaging is completed, as shown in fig. 4.
It should be noted that: during the design of the ultra-short-focus projection lens 42, it is determined that the adjustment of the focal length of the ultra-short-focus projection lens 42 can be realized by adjusting one or more of the first lens group, the second lens group and the third lens group; that is, the projection lens 42 includes at least one movable lens group that can move back and forth along the optical axis. The movable lens group can be any one or more groups of the first lens group, the second lens group and/or the third lens group.
The embodiment of the present invention is described by taking an example of adjusting the position of the second lens group in the second lens barrel 422, and the first lens group and the third lens group are kept still. Certainly, if the positions of the first lens group and the second lens group need to be adjusted simultaneously, the first lens group may adopt a focusing method and a focusing system of the ultra-short-focus projection lens similar to the second lens group to adjust the focal length of the first lens group, so that the first lens group and the second lens group are adjusted simultaneously.
Referring to fig. 4 to 5, the ultra-short focus projection lens 42 in the embodiment of the present invention includes a fixed lens group and a movable lens group. The fixed lens group includes a first lens group located in the first lens barrel 421 and a third lens group located in the third lens barrel 423. The movable lens group is a second lens group located in the second barrel 422. The first lens barrel 421, the second lens barrel 422 and the third lens barrel 423 are sequentially arranged along the light emitting direction of the light valve 1 of the projection system, and the second lens group is configured to move only within the effective focusing range, i.e. the second lens group moves back and forth along the optical axis in the second lens barrel 422. The dashed lines in fig. 4 and 5 represent the optical axis in the projection system.
The movable mirror group comprises a first lens 4221, a second lens 4222 and a third lens 4223 which are sequentially arranged along the light emitting direction of the light valve 1. The first lens element 4221 is disposed adjacent to the first lens group, and the third lens element 4223 is disposed adjacent to the third lens group. The first lens 4221 is a spherical lens having positive refractive power, and the second lens 4222 and the third lens 4223 are spherical lenses having negative refractive power.
Referring to fig. 4 to 6, an embodiment of the present invention further provides an ultra-short focus projection lens focusing system for adjusting a distance between a movable mirror group in a projection device and a projection screen, including: the distance measuring device 5 is used for measuring the projection distance between the projection equipment and the projection screen by the distance measuring device 5; the driving motor 6 is connected with the movable mirror group and drives the movable mirror group to move along the optical axis; the controller, the controller is connected with range unit 5, the equal electricity of CD-ROM drive motor 6, and the controller includes: the storage module is used for presetting a focusing parameter table of the corresponding relation between the projection distance and the preset position range; and the control module is used for controlling the driving motor 6 to drive the movable mirror group to move to a preset position range according to the projection distance obtained by the distance measuring device 5 and the focusing parameter table stored by the storage module.
The ultrashort-focus projection lens focusing system provided by the embodiment of the invention stores a focusing parameter table of the corresponding relation between the preset projection distance and the preset position range in a storage module of a controller in advance. And then when the position of the movable mirror group needs to be adjusted, the controller is used for acquiring the projection distance between the projection equipment and the projection screen, which is measured by the distance measuring device 5, searching a preset position range corresponding to the preset horizontal distance corresponding to the current projection distance from a focusing parameter table in the storage module, sending a control instruction to the driving motor 6 by the controller, and controlling the movable mirror group to move to the preset position range after the driving motor 6 receives the control instruction. Compared with the prior art, the embodiment of the invention can move the movable mirror group to the position near the focusing position corresponding to the current projection distance by moving the movable mirror group once; meanwhile, as the focusing parameter table is stored in the storage module in advance, the movable lens group does not move step by step in the process of moving to the preset position range, so that the focusing time of the movable lens group is shortened, and the focusing efficiency of the movable lens group is improved.
In order to judge whether the display effect of the projection image on the projection screen is improved after the movable mirror group moves, the ultra-short-focus projection lens focusing system further comprises: the image acquisition device 7 is used for acquiring a projection image on the projection screen, and is electrically connected with the controller; the controller further comprises: the image processing module is used for acquiring the definition value of the projected image; the storage module is further used for storing a preset definition value of the projected image, and the control module is further used for determining whether the movable mirror group needs to be focused or not according to the definition value obtained by the image processing module and the preset definition value stored by the storage module. For example, the controller acquires a projection image acquired by the image acquisition device 7, and the controller can acquire the projection image and send the projection image to the image processing module, and the image processing module obtains a definition value of the projection image through digital image processing and compares the definition value with a preset definition value in the storage module. And if the definition value of the projected image is smaller than the preset definition value, focusing is required on the movable lens group, and if the definition value of the projected image is equal to the preset definition value, focusing is not required on the movable lens group.
Further, the storage module and the image processing module can be integrated with the control module. Optionally, the storage module, the image processing module and the control module are separately arranged, wherein the storage module, the image processing module and the control module are all electrically connected to realize signal communication.
Further, range unit 5 is distance sensor, and range unit 5 installs on projection equipment's shell, and is used for measuring the projection distance between projection equipment to the projection screen, compares in the manual work and measures the back, with the measured value input, detects the projection distance between projection equipment and the projection screen through distance sensor, can make the result of measuring projection distance more accurate, and above-mentioned embodiment is simple and convenient, easily realizes.
Optionally, the distance sensor is any one of an ultrasonic distance measuring sensor, a laser distance measuring sensor, an infrared distance measuring sensor or a radar distance measuring sensor. Of course, distance sensors may also be provided around the housing of the projection device, thereby further improving the accuracy of the measured projection distance. Optionally, the above-mentioned collecting device is a camera, which is installed on a housing of the projection device, and is used for collecting the projection image on the projection screen.
Further, the drive motor 6 is a stepping motor or a dc motor. In the embodiment of the invention, the initial position (factory position) of the movable lens group is determined, so that the moving direction and the moving displacement of the movable lens group can be obtained by recording the rotating angle and the rotating direction of the stepping motor, the current position of the movable lens group can be obtained, a position sensor is not required to be arranged, the number of parts in the automatic focusing system is reduced, and the automatic focusing system is simple in structure.
Optionally, the movable mirror group includes a first lens 4221, a second lens 4222 and a third lens 4223 sequentially arranged along the light emitting direction of the light valve, and the stepping motor includes a first stepping motor and a second stepping motor, where the first stepping motor is connected to the first lens 4221 and the second lens 4222 and is configured to drive the first lens 4221 and the second lens 4222 to simultaneously move along the optical axis, and the second stepping motor is connected to the third lens 4223 and is configured to drive the third lens 4223 to move along the optical axis.
Based on the above embodiment, the storage module of the autofocus system needs to store a plurality of preset position ranges corresponding to the first lens 4221, the second lens 4222 and a plurality of preset position ranges corresponding to the third lens 4223 under a plurality of projection distance products. For example, when the projected image area is 80 inches, the predetermined position range M corresponding to the first lens 4221 and the second lens 4222 1 A predetermined position range M corresponding to the third lens 4223 2 . When the projection screen area is 100 inches, the preset position range M 'corresponding to the first lens 4221 and the second lens 4222' 1 Preset position range M 'corresponding to third lens 4223' 2 . When the area of the projection picture is 120 inches, the preset position ranges M corresponding to the first lens 4221 and the second lens 4222 " 1 A preset position range M corresponding to the third lens 4223 " 2 . The adjustment processes of the first lens element 4221 and the second lens element 4222 are similar to the adjustment process of the movable lens group, and the adjustment process of the third lens element 4223 is similar to the adjustment process of the movable lens groupAnd (6) like.
If the current projection screen area is 100 inches, when the projection screen area increases from 100 inches, the projection distance of the movable lens group needs to be increased to increase the size of the projection image, at this time, the first lens 4221 and the second lens 4222 move along the optical axis direction away from the first lens group in the first lens barrel 421, and the third lens 4223 moves along the optical axis direction close to the first lens group in the first lens barrel 421. If the current projected image area is 100 inches, when the projected image area is reduced from 100 inches, the projection distance of the movable mirror group needs to be reduced to reduce the size of the projected image, at this time, the first lens 4221 and the second lens 4222 move along the optical axis direction to approach the first mirror group in the first barrel 421, and the third lens 4223 moves along the optical axis direction to get away from the first mirror group in the first barrel 421.
Optionally, the movable mirror group includes a first lens 4221, a second lens 4222 and a third lens 4223 sequentially arranged along the light emitting direction of the light valve, and the stepping motor includes a first stepping motor, a second stepping motor and a third stepping motor. The first stepping motor is connected to the first lens 4221 and configured to drive the first lens 4221 to move along the optical axis, the second stepping motor is connected to the second lens 4222 and configured to drive the second lens 4222 to move along the optical axis, and the third stepping motor is connected to the third lens 4223 and configured to drive the third lens 4223 to move along the optical axis.
Based on the above embodiment, the storage module of the autofocus system needs to store a plurality of preset position ranges corresponding to the first lens 4221, a plurality of preset position ranges corresponding to the second lens 4222, and a plurality of preset position ranges corresponding to the third lens 4223 at a plurality of horizontal distances. The adjustment process of the first lens 4221, the second lens 4222 and the third lens 4223 is similar to the adjustment process of the movable lens group.
The embodiment of the invention also provides an ultra-short-focus projector, which adopts the ultra-short-focus projection lens focusing system, so that the time required by the focusing process of the ultra-short-focus projector adopting the ultra-short-focus projection lens focusing system is shorter, and the focusing efficiency is higher.
It should be noted that: it is necessary to re-determine whether the movable lens group needs to be focused when any of the following conditions occurs: when the projection device is started, or when the projection device is restarted, or when the distance measuring device detects that the distance between the projection device and the projection screen changes, whether the movable mirror group needs to be focused or not needs to be determined again.
In the description herein, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A focusing method of an ultra-short-focus projection lens is characterized in that the ultra-short-focus projection lens comprises the following steps:
a fixed lens group and a movable lens group;
a driving motor to drive the movable mirror group to move in a direction of an optical axis;
the ultrashort-focus projection lens focusing method comprises the following steps:
receiving a focusing instruction;
acquiring a current projection distance between the projection equipment and a projection screen;
comparing the current projection distance with a plurality of preset projection distances, wherein the plurality of preset projection distances correspond to a plurality of first preset position ranges of the movable mirror group one by one, a second preset position range exists between two adjacent first preset position ranges, and two end point values of the second preset position range are respectively two end point values which are close to each other in two adjacent first preset position ranges corresponding to the two adjacent preset projection distances;
if the current projection distance is equal to one of the preset projection distances, controlling the driving motor to drive the movable mirror group to move to the first preset position range;
and if the current projection distance is located between two adjacent preset projection distances in the plurality of preset projection distances, controlling the driving motor to drive the movable mirror group to move to the second preset position range.
2. The ultra-short-focus projection lens focusing method of claim 1, further comprising, after the controlling the driving motor to drive the movable mirror group to move to the first preset position range:
controlling a driving motor to drive the movable mirror group to move within the first preset position range by a preset distance;
acquiring a projection image of a current projection screen;
obtaining a current definition value of the projected image according to the projected image;
if the current definition value is equal to a preset definition value, controlling a driving motor to stop;
and if the current definition value is smaller than a preset definition value, returning to the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by a preset distance.
3. The ultra-short-focus projection lens focusing method according to claim 2, wherein the receiving of the focusing instruction specifically includes:
acquiring a projection image of a current projection screen;
obtaining a current definition value of the projected image according to the projected image;
if the current definition value is equal to a preset definition value, controlling a driving motor to stop;
and if the current definition value is smaller than the preset definition value, returning to the step of receiving the focusing instruction.
4. The ultra-short focus projection lens focusing method of claim 3, wherein after said comparing said current projection distance with a plurality of preset projection distances, before said controlling said driving motor to drive said movable mirror group to move to said first preset position range, further comprising:
acquiring the current position of the movable lens group;
and if the current projection distance is equal to one of the preset projection distances and the current position of the movable mirror group is located outside a first preset position range, controlling the driving motor to drive the movable mirror group to move to an end position, closest to the current position of the movable mirror group, in the first preset position range, and returning to the step of receiving a focusing instruction.
5. The method of claim 4, wherein if the current projection distance is equal to one of the plurality of preset projection distances and the current position of the movable lens group is outside a first preset position range, the controlling the driving motor to drive the movable lens group to move to an end position in the first preset position range closest to the current position of the movable lens group comprises:
when X (t) < X 1 '(j)，X 1 ' (j) is the first end point position of the first preset position range, controlling the driving motor to drive the movable mirror group to move to X 1 ' (j) and returning to the step of receiving a focus command;
when X (t) > X 2 '(j)，X 2 ' (j) is the second end point position of the first preset position range, controlling the driving motor to drive the movable mirror group to move to X 2 ' (j) and returning to the step of receiving a focus command;
wherein, X 1 '(j)＜X 2 '(j)。
6. The ultra-short focus projection lens focusing method of claim 3, wherein after said comparing said current projection distance with a plurality of preset projection distances, before said controlling said driving motor to drive said movable mirror group to move to said first preset position range, further comprising:
acquiring the current position of the movable lens group;
and if the current projection distance is equal to one of the preset projection distances and the current position of the movable mirror group is within the first preset position range, returning to the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by a preset distance.
7. The ultra-short focus projection lens focusing method of claim 6, wherein if the current sharpness value is smaller than a preset sharpness value, the step of returning to the control driving motor to drive the movable mirror group to move within the first preset position range by a preset distance specifically comprises:
if the current definition value is smaller than a preset definition value and the current definition value is larger than the previous definition value, controlling the current rotating direction of the driving motor to keep the previous rotating direction, and returning to the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by a preset distance;
if the current definition value is smaller than the preset definition value and the current definition value is smaller than the previous definition value, the current rotating direction of the driving motor is changed to be the opposite direction of the previous rotating direction, and the step of controlling the driving motor to drive the movable mirror group to move within the first preset position range by the preset distance is returned.
8. An ultra-short-focus projector, characterized in that the ultra-short-focus projection lens focusing method of any one of the claims 1 to 7 is adopted.
9. An ultra-short-focus projection lens focusing system for adjusting the distance between a movable lens group and a projection screen in a projection device, comprising:
the distance measuring device is used for measuring the projection distance between the projection equipment and the projection screen;
the driving motor is connected with the movable mirror group and drives the movable mirror group to move along an optical axis;
a controller, the controller with range unit, the even electricity of driving motor is connected, the controller includes:
the storage module is used for presetting a focusing parameter table of the corresponding relation between the projection distance and the preset position range;
the control module is used for controlling the driving motor to drive the movable mirror group to move once to the preset position range according to the projection distance obtained by the distance measuring device and the focusing parameter table stored by the storage module;
the image acquisition device is used for acquiring a projection image on the projection screen and is electrically connected with the controller;
the controller further includes:
the image processing module is used for acquiring a definition value of the projected image;
the storage module is further used for storing a preset definition value of the projected image, and the control module is further used for determining whether the movable mirror group needs to be focused or not according to the definition value obtained by the image processing module and the preset definition value stored by the storage module.
10. An ultra-short-focus projector comprising the ultra-short-focus projection lens focusing system of claim 9.
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