JPH05333257A - Lens driving device - Google Patents

Abstract

PURPOSE:To obtain a lens driving device capable of always performing focusing and zooming in the shortest time irrespective of the load fluctuation of a lens. CONSTITUTION:The device is provided with detecting means 2 and 3 for detecting a lens driving condition, a driving condition storing means for storing plural driving conditions which are previously obtained in accordance with the load fluctuation, a driving condition selecting means 4 for selecting the driving condition detected by the detecting means 2 and 3 out of the driving condition storing means 1 and a lens driving means 5 for driving the lens in accordance with the selected driving condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving device for driving a photographing lens such as autofocus and autozoom to a predetermined position in an optical device.

[0002]

2. Description of the Related Art A conventional lens driving device of this type detects a focus shift amount by a focus detection means in the case of autofocus, calculates a shift amount of a focus lens corresponding to the focus shift amount, and The focus lens is driven by the amount calculated. In the case of auto zoom, the amount of movement of the zoom lens is calculated by comparing the preset zoom position according to the shooting conditions with the current zoom position, and the zoom lens is driven by the amount calculated by the calculation.

In any of the above cases, this lens drive is
It is preferable to drive as quickly as possible, and the drive is performed so that the acceleration and deceleration times are the shortest.

However, in general, the temperature of the photographing location and the photographing posture are not constant, and the photographing posture is not always horizontal, and the camera may be oriented in the vertical direction. For example, when the weight of the lens is against gravity. In the case of the same direction as gravity, the driving conditions for satisfying the stop position accuracy and driving in the shortest time are different. However, in reality, the lens driving is performed under a common driving condition by allowing the driving time to be extended as a condition satisfying both of them.

In recent years, with the increase in the speed of autofocus and autozoom, the rotation angle of focus and zoom has been reduced as much as possible to shorten the driving time, but the helicoid screw and the cam lead angle have to be increased. The influence of the above attitude difference cannot be ignored.

[0006]

However, in the above-mentioned conventional example, since the camera is configured to satisfy the driving condition when the camera is oriented in the vertical direction, it is impossible to reduce the driving time in the horizontal state which is frequently used. There was a problem.

It is an object of the present invention to obtain a lens driving device that solves the above problems.

[0008]

[Means for Solving the Problems]

(1) Detecting means for detecting a driving condition of a lens, driving condition storing means for storing a plurality of driving conditions obtained in advance corresponding to load variations, and driving conditions detected by the detecting means are described above. By providing the driving condition selecting unit selected from the driving condition storing unit and the lens driving unit driving the lens under the selected driving condition, focusing and zooming are always performed in the shortest time regardless of the change of the photographing condition. be able to.

(2) Drive condition storage means for storing a plurality of drive conditions obtained in advance corresponding to load fluctuations,
A driving condition selecting unit that selects the driving condition stored in the driving condition storing unit, a lens driving unit that drives the lens under the selected driving condition, and a driving state that is driven under the selected driving condition are detected. A drive state detection means, a proper drive state storage means for storing a preset proper drive state, and a comparison means for comparing the output of the drive state detection means with the output of the proper drive state storage means, By having a learning function of selecting another driving condition by the driving condition selecting means when the driving condition driven under the selected driving condition does not match the proper driving condition,
Even if the load condition changes, the drive condition can be optimized and the lens drive can be completed in the shortest time without requiring another detection means for detecting the load characteristic and increasing the manufacturing cost.

[0010]

【Example】

First Embodiment FIG. 1 shows a first embodiment of the present invention, which is a block diagram best representing the features of the present invention.
Reference numeral 1 is a drive condition storage means for storing a plurality of drive conditions corresponding to the load fluctuation of the lens which is actually measured and confirmed by the temperature of the shooting place and the difference in the shooting attitude. 2 is a temperature detecting means such as a thermistor. Is a posture difference detecting means for detecting the direction of gravity, such as a mercury switch, and 4 is the temperature detecting means 2.
Further, the drive condition selecting means 5 for selecting the drive condition from the drive condition storing means 1 using the detection information from the attitude difference detecting means 3 as one of the selection elements is the drive condition selected by the drive condition selecting means 4. Therefore, it is a lens driving means for driving the lens.

FIG. 2 is a diagram showing the relationship between lens drive amount and speed according to the first embodiment of the present invention. A-b-d- in the figure
The f-g diagram represents the relationship between the lens drive amount and the speed from the acceleration start to the deceleration stop of the load (appropriate load) when the shooting posture is horizontal at room temperature.

When the load is heavy, for example, in a photographing state in which the lens is driven against gravity at a low temperature, the load of the lens itself serves as a brake and the speed is rapidly reduced.
A-b-e-f- that starts deceleration from the position of point e close to
When the driving conditions are set so as to have a line g, driving can be completed in the shortest time.

Further, when the load is light, for example, in a photographing state in which the lens is driven in the same direction as gravity at high temperature, the brake cannot be obtained due to the load of the lens itself, so that the deceleration is not easily performed, and the stop position g is reached. On the other hand, it is necessary to set the driving conditions in the ab-b-c-f-g diagram that starts deceleration from the position of point c, which is quite before this.

Although the relationship between the driving amount and the speed during acceleration is strictly different depending on the load, it is expressed as the same for any load in FIG. 2 for convenience.

The illustrated examples are both extremes, and the combination of the photographing temperature and the photographing posture difference is an independent condition, so there are other combinations, but they are omitted. Further, as the lens driving amount detecting means in the embodiment of the present invention, a lens driving actuator, a lens, or a pulse encoder that generates an output proportional to the moving amount to any of the interlocking mechanisms may be used, and the lens speed It can be detected by the pulse interval.

Next, the operation of the first embodiment having the above configuration will be described. Assuming that the photographing temperature detected by the temperature detecting unit 2 is room temperature and the photographing posture detected by the posture difference detecting unit 3 is horizontal, the driving condition that is ab-d-e-f-g diagram is driven. Select from the condition storage means 1. When the lens is turned up or down, a
A driving condition that is a -b-c-f-g diagram or an a-b-e-f-g diagram is selected from the driving condition storage unit 1. Then, the lens driving means 5 drives the lens in accordance with the selected driving condition. Second Embodiment FIG. 3 is a block diagram showing a second embodiment of the present invention.
Is a drive condition storage means for storing a plurality of drive conditions corresponding to the load variation of the lens, which is measured and confirmed in advance, depending on the temperature of the shooting place and the difference in the shooting posture, and 12 is one of the plurality of drive conditions Drive condition selecting means for selecting 1
3 is a lens driving means for driving the lens under the driving condition selected by the driving condition selecting means 12, 14 is a driving state detecting means for detecting the driving state of the lens, 15 is a proper driving condition storing means, and 16 is the proper driving. State storage means 15
Comparing means for comparing the proper drive state stored in the drive state with the drive state detected by the drive state detecting means 14, and returns the comparison result to the drive condition selecting means 12 to add it to the selection condition.

Next, the operation will be described with reference to the flow chart in FIG. First, if there is a lens drive command (ST4-
1) It is determined whether the deceleration start position is selected (ST4-2). For example, when the power is turned off and the drive condition is not set, that is, when the determination result is NO, the standard deceleration start position d is selected as the standard deceleration start position (ST4-3).

On the other hand, when the above determination result is YES, the lens is driven (ST4-4), and the low speed drive amount g at this time is driven.
-G 'is detected. As shown in FIG. 5A, when deceleration is started at the deceleration start position d, but the load of the lens becomes heavy due to the temperature and the attitude difference, a-b-c-d-f'-f-g.
It becomes a diagram and low speed driving occurs between g'-g (ST4
-5). Then, it is determined in ST4-6 whether this g-g 'is 0≤g-g'≤constant. If YES, the process returns to ST4-1, and if NO, g-g'> constant ST4-7. To judge. In the case of FIG. 5A, the determination result of ST4-7 is YES, that is, it is larger than the predetermined amount set in advance, so the deceleration start position is changed from d to e (ST4-
8) Wait for the next drive command.

Further, when the lens load is light, FIG.
As described above, the vehicle cannot satisfactorily decelerate at the predetermined stop position g, and the driving is reduced at the position of g ′, and the low speed driving section has a negative value at gg ′, which means overrun. In this case ST4-
The determination result of 7 is NO, and the deceleration start position is changed from d to c (ST4-9).

Further, as for the attitude difference, the load condition is reversed depending on the driving direction, so that two systems are required to select the driving condition.

FIG. 6 is a flow chart showing another embodiment according to the present invention. In this embodiment, the time tg-tg 'of the low speed driving section is used as an element for judging the proper driving state, not the amount of the low speed driving section. As far as the difference is made, the operation process is the same as in the first embodiment as shown in ST6-1 to ST6-9.
ST4-1 to ST4-9. When an overrun occurs in this embodiment, the overtime can be calculated from the difference between the time of the drive amount g and the time of the stop position g ′ in FIG. 5B.

[0022]

As described above, according to the first aspect of the invention, the load variation of the lens is detected, and the lens driving condition is selected according to the detected load variation. Focusing and zooming can be performed with.

According to the second aspect of the present invention, it is determined whether the driving state of the lens matches the proper driving state, and if they do not match, another driving condition is selected to drive the lens. Since the learning function is provided in (1), there is an effect that an optimum driving condition can be set by a simple and inexpensive configuration without requiring another detecting means for detecting load characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a relationship diagram between a lens driving amount and a speed according to the first exemplary embodiment.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of the second embodiment.

FIG. 5 is a relationship diagram between a lens drive amount and a speed according to the second embodiment.

FIG. 6 is a flowchart for explaining the operation of the third embodiment.

[Explanation of symbols]

 1 Drive Condition Storage Means 2 Temperature Detection Means (Detection Means) 3 Attitude Difference Detection Means (Detection Means) 4 Drive Condition Selection Means 5 Lens Drive Means

Claims (2)

[Claims] 1. A detecting means for detecting a driving condition of a lens, a driving condition storing means for storing a plurality of driving conditions obtained in advance corresponding to a load change, and a driving condition detected by the detecting means. A lens driving device, comprising: a driving condition selecting unit that selects from the driving condition storing unit; and a lens driving unit that drives the lens under the selected driving condition. 2. A drive condition storage means for storing a plurality of drive conditions obtained in advance corresponding to a load change, and a drive condition selection means for selecting the drive condition stored in the drive condition storage means. Lens driving means for driving the lens under the selected driving condition, driving state detecting means for detecting the driving state driven under the selected driving condition, and appropriate driving state storage means for storing a preset appropriate driving state. If the drive state driven under the selected drive condition does not match the proper drive state, the output state of the drive state detection means and the output of the proper drive state storage means are compared. A lens driving device having a learning function of selecting another driving condition by the driving condition selecting means.