US4888609A — Automatic focus adjusting apparatus

Claim 1

Independent Claim 402 words

An automatic focus adjusting apparatus for adjusting automatically a focus condition of an objective lens, comprising: photodetecting means of a charge accumulating type for detecting the light intensity distribution of an image of an object to be focused, to produce an accumulated charge signal representing the detected light intensity distribution; brightness discriminating means for discriminating whether or not the brightness of the image is above a predetermined level; calculating means for calculating the focus condition of the objective lens in accordance with the accumulated charge signal; reliability discriminating means for discriminating whether or not the result of the calculation of the calculating means based on the accumulated charge signal is reliable; lens shifting means for shifting the objective lens along the optical axis thereof, and control means for controlling the calculating means and the lens shifting means in accordance with the output of the calculating means, the output of the brightness discriminating means, and the output of the reliability discriminating means such that; if the reliability discriminating means discriminates that the result of the calculation of the calculating means is reliable, the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means on the basis of the accumulated charge signals, and if the reliability discriminating means discriminates that the result of the calculation of the calculating means is not reliable, the objective lens is shifted by the lens shifting means to find a reliable position where a result of the calculation of the calculating means is discriminated to be reliable with repeatedly calculating the focus condition on the basis of the accumulated charge signals produced repeatedly, and, when the reliable position is discriminated to be found, the objective lens is controlled such that: the objective lens is shifted while repeating the calculation of the calculating means, if the brightness discriminating means discriminates that the brightness of the image is above a predetermined level, and the objective lens is once stopped, and the calculating means is operated for calculating the focus condition of the objective lens during the stoppage of the objective lens, and after that the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means during the stoppage of the objective lens, if the brightness discriminating means discriminates that the brightness of the image is below the predetermined level.

Claim 2

Dependent Claim 402 words

An automatic focus adjusting apparatus for adjusting automatically a focus condition of an objective lens, comprising: photodetecting means of a charge accumulating type for detecting the light intensity distribution of an image of an object to be focused, to produce an accumulated charge signal representing the detected light intensity distribution; brightness discriminating means for discriminating whether or not the brightness of the image is above a predetermined level; calculating means for calculating the focus condition of the objective lens in accordance with the accumulated charge signal; reliability discriminating means for discriminating whether or not the result of the calculation of the calculating means based on the accumulated charge signal is reliable; lens shifting means for shifting the objective lens along the optical axis thereof, and control means for controlling the calculating means and the lens shifting means in accordance with the output of the calculating means, the output of the brightness discriminating means, and the output of the reliability discriminating means such that; if the reliability discriminating means discriminates that the result of the calculation of the calculating means is reliable, the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means on the basis of the accumulated charge signals, and if the reliability discriminating means discriminates that the result of the calculation of the calculating means is not reliable, the objective lens is shifted by the lens shifting means to find a reliable position where a result of the calculation of the calculating means is discriminated to be reliable with repeatedly calculating the focus condition on the basis of the accumulated charge signals produced repeatedly, and, when the reliable position is discriminated to be found, the objective lens is controlled such that: the objective lens is shifted while repeating the calculation of the calculating means, if the brightness discriminating means discriminates that the brightness of the image is above a predetermined level, and the objective lens is once stopped, and the calculating means is operated for calculating the focus condition of the objective lens during the stoppage of the objective lens, and after that the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means during the stoppage of the objective lens, if the brightness discriminating means discriminates that the brightness of the image is below the predetermined level.

Claim 3

Dependent Claim 60 words

An automatic focus adjusting apparatus as claimed in claim 1, wherein the brightness discriminating means includes a time period judging means for judging whether or not the photodetecting means takes more than a predetermined period of time to accumulate a predetermined amount of electric charge to discriminate whether or not the brightness of the image is above the predetermined level.

Claim 4

Dependent Claim 82 words

An automatic focus adjusting apparatus as claimed in claim 1, further comprising amplifying means for amplifying the accumulated charge signal produced by the photodetecting means at a gain determined by the amplitude of the accumulated charge signal, and wherein the brightness discriminating means includes gain judging means for judging whether or not the degree of the gain of the amplifying means is greater than a predetermined gain to discriminate whether or not the brightness of the image is above the predetermined level.

Claim 5

Dependent Claim 277 words

An automatic focus adjusting apparatus for adjusting automatically a focus condition of an objective lens, comprising: photodetecting means of a charge accumulating type for detecting the light intensity distribution of an image of an object to be focused, to produce an accumulated charge signal representing the detected light intensity distribution; calculating means for calculating the focus condition of the objective lens in accordance with the accumulated charge signal; reliability discriminating means for discriminating whether or not the result of the calculation of the calculating means based on the accumulated charge signal is reliable; lens shifting means for shifting the objective lens along the optical axis thereof; end judging means for judging whether or not the objective lens has reached one of the ends of a predetermined movable distance range of the objective lens, and control means for controlling the calculating means and the lens shifting means in accordance with the output of the calculating means, the output of the reliability discriminating means, and the output of the end judging means such that: if the reliability discriminating means discriminates that the result of the calculation of the calculating means is reliable, the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means on the basis of the accumulated charge signals, and if the reliability discriminating means discriminates that the result of the calculation is not reliable, the objective lens is shifted towards its nearest focusing position at first and thereafter is shifted towards its infinity focusing position to find the reliable position, and is stopped at the indinity focusing position if the reliable position is not found.

Claim 6

Dependent Claim 277 words

An automatic focus adjusting apparatus for adjusting automatically a focus condition of an objective lens, comprising: photodetecting means of a charge accumulating type for detecting the light intensity distribution of an image of an object to be focused, to produce an accumulated charge signal representing the detected light intensity distribution; calculating means for calculating the focus condition of the objective lens in accordance with the accumulated charge signal; reliability discriminating means for discriminating whether or not the result of the calculation of the calculating means based on the accumulated charge signal is reliable; lens shifting means for shifting the objective lens along the optical axis thereof; end judging means for judging whether or not the objective lens has reached one of the ends of a predetermined movable distance range of the objective lens, and control means for controlling the calculating means and the lens shifting means in accordance with the output of the calculating means, the output of the reliability discriminating means, and the output of the end judging means such that: if the reliability discriminating means discriminates that the result of the calculation of the calculating means is reliable, the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means on the basis of the accumulated charge signals, and if the reliability discriminating means discriminates that the result of the calculation is not reliable, the objective lens is shifted towards its nearest focusing position at first and thereafter is shifted towards its infinity focusing position to find the reliable position, and is stopped at the indinity focusing position if the reliable position is not found.

Claim 7

Dependent Claim 183 words

An automatic focus adjusting apparatus as claimed in claim 4, further comprising auxiliary light discriminating means for discriminating whether an auxiliary light device is used for illuminating the object, and wherein the control means controls the lens shifting means in accordance with the output of the auxiliary light discriminating means such that: if the auxiliary light discriminating means discriminates that the auxiliary light device is used, the objective hens is shifted towards one end of the predetermined movable distance range to find the reliable position on the basis of the focus condition calculated by the calculating means, and the objective lens is shifted towards another end of the predetermined movable distance range when the end judging means has judged that the objective lens has reached one end of the predetermined movable distance range without finding the reliable position, and if the auxiliary light discriminating means discriminates that the auxiliary light device is used, the objective lens is shifted towards the infinity focusing position to find the reliable position, and is stopped at the infinity focusing position if the reliable position is not found.

Claim 8

Dependent Claim 326 words

An automatic focus adjusting apparatus for adjusting automatically a focus condition of an objective lens, comprising: photodetecting means of a charge acumulating type for detecting the light intensity distribution of an image of an object to be focused, to produce an accumulated charge signal representing the detected light intensity distribution; calculating means for calculating the focus condition of the objective lens in accordance with the accumulated charge signal; reliability discriminating means for discriminating whether or not the result of the calculation of the calculating means based on the accumulated charge signal is reliable; lens shifting means for shifting the objective lens along the optical axis thereof; end judging means for judging whether or not the objective lens has reached one of the ends of a predetermined movable distance range of the objective lens, and control means for controlling the photodetecting means, the calculating means and the lens shifting means in accordance with the output of the calculating means, the output of the reliability discriminating means, and the end judging means such that: if the reliability discriminating means discriminates that the result of the calculation of the calculating means is reliable, the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means on the basis of the accumulated charge signals, and if the reliability discriminating means discriminates that the result of the calculation of the calculating means is not reliable, the objective lens is shifted by the lens shifting means to find a reliable position where a result of the calculation of the calculating means is discriminated to be reliable, and if the end judging means has judged that the objective lens has reached one end of the predetermined movable distance range, either of the present accumulating operation of the photodetecting means and the present calculating operation of the calculating means is made invalid with interrupting further shifting of the objective lens in the shifted direction.

Claim 9

Dependent Claim 326 words

An automatic focus adjusting apparatus for adjusting automatically a focus condition of an objective lens, comprising: photodetecting means of a charge acumulating type for detecting the light intensity distribution of an image of an object to be focused, to produce an accumulated charge signal representing the detected light intensity distribution; calculating means for calculating the focus condition of the objective lens in accordance with the accumulated charge signal; reliability discriminating means for discriminating whether or not the result of the calculation of the calculating means based on the accumulated charge signal is reliable; lens shifting means for shifting the objective lens along the optical axis thereof; end judging means for judging whether or not the objective lens has reached one of the ends of a predetermined movable distance range of the objective lens, and control means for controlling the photodetecting means, the calculating means and the lens shifting means in accordance with the output of the calculating means, the output of the reliability discriminating means, and the end judging means such that: if the reliability discriminating means discriminates that the result of the calculation of the calculating means is reliable, the objective lens is shifted by the lens shifting means in accordance with the result of the calculation of the calculating means on the basis of the accumulated charge signals, and if the reliability discriminating means discriminates that the result of the calculation of the calculating means is not reliable, the objective lens is shifted by the lens shifting means to find a reliable position where a result of the calculation of the calculating means is discriminated to be reliable, and if the end judging means has judged that the objective lens has reached one end of the predetermined movable distance range, either of the present accumulating operation of the photodetecting means and the present calculating operation of the calculating means is made invalid with interrupting further shifting of the objective lens in the shifted direction.

Claim 10

Dependent Claim 35 words

An automatic focus adjusting apparatus as claimed in claim 6, further comprising restarting means for restarting either of the accumulating operation of the photodetecting means, after the present accumulating operation has been once made invalid.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-12-18	1993-06-19	1993-12-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-12-18	1997-06-19	1997-12-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-12-18	2001-06-19	2001-12-19	$7700.00	Window Closed / Lapsed

Automatic focus adjusting apparatus

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