Powered zoom device
First Claim
Patent Images
1. A powered zoom device for a camera including a lens having a variable magnification lens group adopted to have a focal length changed in response to a displacement of said lens group in a direction along an optical axis, comprising:
- lens-moving means for driving said magnification lens group; and
,control means for driving said lens-moving means so as to move said magnification lens group with a constant changing rate of said focal length, said control means employing a speed compensation process to ensure that said lens-moving means is driven at said constant changing rate.
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Abstract
A powered zoom device for a camera includes a lens having a variable magnification lens group that is adapted to be changed in a focal length in response to a displacement thereof in a direction along an optical axis. A magnification lens group is driven. The driving of the magnification lens group is controlled so as to move the magnification lens group with a constant rate of the focal length.
22 Citations
29 Claims
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1. A powered zoom device for a camera including a lens having a variable magnification lens group adopted to have a focal length changed in response to a displacement of said lens group in a direction along an optical axis, comprising:
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lens-moving means for driving said magnification lens group; and
,control means for driving said lens-moving means so as to move said magnification lens group with a constant changing rate of said focal length, said control means employing a speed compensation process to ensure that said lens-moving means is driven at said constant changing rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A device for electrically changing a focal length of a lens including a lens-moving mechanism for driving said lens so as to change said focal length of said lens and means for driving said lens-moving mechanism, comprising:
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correction value memory means for memorizing a changing rate of said focal length by means of said lens-moving mechanism relative to a predetermined amount of displacement of said drive means with respect to a plurality of focal lengths; and
,control means for controlling said drive means so as to maintain said changing rate of said focal length at a constant value when a predetermined command is inputted thereinto, said control means employing a speed compensation process that uses said changing rate memorized in said correction value memory to ensure that said lens-moving mechanism is driven at said constant changing rate. - View Dependent Claims (15, 16, 17, 18)
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19. A powered zoom device for a camera including a lens having a variable magnification lens group adopted to have a focal length changed in response to a displacement of said lens group in a direction along an optical axis, comprising:
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lens-moving means for driving said magnification lens group; and
,control means for driving said lens-moving means so as to move said magnification lens group with a constant changing rate of said focal length, wherein said control means drives said lens-moving means using correction data β
that is determined according to a formula;
space="preserve" listing-type="equation">β
=f'"'"'(xn)/f'"'"'(xmax),wherein; f'"'"'(xmax) equals a maximum changing rate of said focal length in a plurality of ranges, and f'"'"'(xn) equals a changing rate of said focal length at a given range. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A device for electrically changing a focal length of a lens including a lens-moving mechanism for driving said lens so as to change said focal length of said lens and means for driving said lens-moving mechanism, comprising:
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a correction value memory for storing a changing rate of said focal length by means of said lens-moving mechanism relative to a predetermined amount of displacement of said drive means with respect to a plurality of focal lengths; and
,a controller for controlling said drive means so as to maintain said changing rate of said focal length at a constant value when a predetermined command is inputted thereinto, wherein said controller drives said lens-moving mechanism using correction data β
that is determined according to a formula;
space="preserve" listing-type="equation">β
=f'"'"'(xn)/f'"'"'(xmax),wherein; f'"'"'(xmax) equals a maximum changing rate of said focal length in a plurality of ranges, and f'"'"'(xn) equals a changing rate of said focal length at a given range.
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29. A powered zoom device for a camera having a variable magnification lens with a focal length is changeable in response to a displacement of said lens in a direction along an optical axis, comprising:
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means for driving said magnification lens; and means for controlling the driving of said magnification lens with a constant focal length changing rate in response to correction data β
that is determined according to a formula;
space="preserve" listing-type="equation">β
=f'"'"'(xn)/f'"'"'(xmax),wherein f'"'"'(xmax) denotes a maximum changing rate of said focal length of said magnification lens in a plurality of focal length ranges, and f'"'"'(xn) denotes a changing rate of said focal length of said magnification lens at a given focal length range.
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Specification