JP2002162553A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera which always performs optimum control, regardless of the ambient condition and of the dispersion of the load of mechanical system, and which makes driving speed compatible with stopping accuracy. SOLUTION: In this camera, a photographic lens 2 is driven via a lens gear train 16 from a motor 15, and a pulse, according to zooming operation by the motor 15 is generated by a pulse generation part 12. The time width of the pulse, outputted from the pulse generation part 12, is shaped by a pulse-shaping part 11 and is compared with a prescribed value by a CPU 10. The drive voltage control of the motor 15 is performed according to output from the CPU 10. Furthermore, the load state of the motor 15 is detected by a current detection part 14. Correction width of the drive voltage of the motor 15 is changed according to load information outputted from the detection part 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera in which a zoom lens is driven by a motor.

[0002]

2. Description of the Related Art In recent years, feedback-type control has been widely used in mechatronics control in cameras. In particular, the zoom lens is required to have a longer focal length and a smaller size when stored. This means that a sudden change in the zoom driving load is likely to occur during the transition from the housed state to the shooting state, and furthermore, the zoom stop position accuracy is required to ensure the shooting performance.

For example, Japanese Patent Application Laid-Open No. 8-179410 discloses that when duty control is performed in controlling a mechanical system in a camera, when a driving speed is different from a predetermined value, an abnormality is determined. An example in which the duty ratio is changed is described.

There is also known a technique in which the voltage is increased or decreased by a constant value in accordance with a pulse width accompanying the driving of a mechanical system, and the driving speed of the mechanical system is adjusted to a predetermined value.

[0005]

SUMMARY OF THE INVENTION The above-mentioned JP-A-8-1
In the control of the mechanical system of the camera described in Japanese Patent No. 79410, feedback type control is effective. However, conventionally, the information of only the pulse corresponding to the operation of the mechanical system cannot determine the degree of the load of the mechanical system, which causes a delay in the control of the mechanical system, and causes excessive correction or excessive correction of the voltage or the like. Problems such as suspension are likely to occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to always carry out optimal control regardless of ambient conditions and variations in the load of a mechanical system, and to achieve both driving speed and stopping accuracy. Is to provide a camera that can

[0007]

That is, the present invention provides a zoom driving means for driving a zoom lens, a pulse generating means for generating a pulse corresponding to a zooming operation by the zoom driving means, and an output from the pulse generating means. Pulse width comparing means for comparing a time width of a pulse with a predetermined value, driving voltage controlling means for controlling a driving voltage of a mechanism driving motor according to an output of the pulse width comparing means, and a load state of the motor. And a load state detecting means for detecting, wherein the correction range of the drive voltage of the motor is changed according to the load information output from the load detecting means.

In the camera according to the present invention, the zoom lens is driven by the zoom driving means, and a pulse according to the zooming operation by the zoom driving means is generated by the pulse generating means. The time width of the pulse output from the pulse generation means is compared with a predetermined value by the pulse width comparison means. The drive voltage control of the mechanism driving motor is performed by the drive voltage control means in accordance with the output of the pulse width comparison means. Further, the load state of the motor is detected by load state detecting means. Then, the correction width of the drive voltage of the motor is changed according to the load information output from the load detection means.

According to the present invention, in feedback mechatronics control such as zooming, the correction amount at the time of feedback is varied by the output of the load state detecting means by adding load detecting means in addition to the conventional pulse width information. . This makes it possible to realize mechanical control that enables stable operation of the mechanical system even when the load of the mechanical system fluctuates.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing an external configuration of a camera according to an embodiment of the present invention, and FIG. 3 is a view showing each state of a photographing lens.

In FIG. 2, a photographing lens 2 and a main switch (SW) 3 are provided on the front surface of the camera body 1 so as to be movable in the direction of arrow A in the figure. In addition, a pop-up strobe 4 is provided at an upper portion of the camera body 1, and a zoom switch (SW) 5 is provided at a rear portion of the camera body 1.
Are provided respectively.

When the main switch 3 is in the OFF position, as shown in FIG. 3A, the photographing lens 2 is in the retracted position indicated by the arrow C in the drawing, and the strobe 4 is in the pop-down position. It is in. Then, when the main switch 3 is turned from OFF to ON (ON), FIG.
As shown in (1), a setup operation is performed in which the photographing lens 2 is extended from the retracted position to the wide end (indicated by the arrow W in the drawing), and the strobe 4 is also brought into the pop-up position.

After the set-up operation, the photographing lens 2 moves from W (wide) to T in accordance with the operation of the zoom switch 5.
(Tele) (see FIG. 3 (c)).

Between the retracted position and the wide position, the cam lead angle is increased to bring the stored photographing lens 2 into the photographing state, the driving load of the photographing lens 2 is large, and the load fluctuation is also large. . Further, since the pop-up operation of the strobe 4 is added, the load is further increased.

When the zoom position is near wide (W) as shown in FIG. 3B, the load is light and the load fluctuation is small. Since this area is involved in actual photographing, it is important to stop the photographing lens 2 at a predetermined position, and a stop precision is required. This requirement for stopping accuracy is consistently required from the wide (W) end to the tele (T) end.

FIG. 1 is a block diagram showing a system configuration of a camera according to an embodiment of the present invention.

The CPU 10 controls the entire camera, and a pulse generator 12 through a pulse shaping unit 11.
However, a motor driver 13 and a current detector 14 are further connected. The pulse generator 12 includes a zoom motor 15 to which the current detector 14 is connected,
A lens gear train 16 for driving the photographing lens 2 is connected.

In such a configuration, the pulse generator 1
The pulse output generated in 2 and shaped by the pulse shaping unit 11 is supplied to the CPU 10. The motor 15
Can change the driving direction and the driving voltage of the motor 15 according to an instruction from the CPU 10.

The motor 15 has a load state detected by a current detection unit 14. An instruction to change the drive voltage of the motor is supplied to the CPU 10 in accordance with the load information output from the current detection unit 14. Is done.

FIG. 4 is a timing chart for explaining the photographing operation of the camera according to the present embodiment.

The output of the pulse shaping section 11 becomes a pulse value and is input to the CPU 10. The time from the rise of the pulse to the rise is compared with a predetermined target time to confirm the speed of the zoom drive speed.

Here, when it is determined that the zoom drive speed is low, the drive voltage of the motor 15 is increased. On the other hand, when it is determined that the zoom drive speed is high, the drive voltage of the motor 15 is reduced.

When correcting the drive voltage of the motor 15,
When the output from the current detection unit 14 is equal to or greater than the load threshold value, a heavy load determination is performed, and the correction amount at the time of correction is changed.

Next, referring to the flowchart of FIG.
The zoom control operation by the CPU 10 will be described.

First, in step S1, a determination is made as to the zoom driving direction of the photographing lens 2. Here, if it is the zoom-up direction, the process proceeds to step S2,
Are rotated forward at the full voltage. On the other hand, in the case of the zoom-down direction, the process shifts to step S3 and the rotation is reversed at the full voltage.

When the motor 15 is driven to rotate in steps S2 and S3, the pulse width time per pulse of the pulse output from the pulse generator 12 is read in step S4. Next, in step S5, the output from the current detection unit 14 is subjected to analog-digital conversion and read as a digital amount.

Then, in steps S6 and S7,
It is determined whether the motor 15 is high speed or low speed. That is, first, in step S6, the pulse width read in step S4 is determined. Here, if the pulse width is smaller than the predetermined reference value A, the speed is determined to be excessive, and the process proceeds to step S13. On the other hand, when the pulse width is larger than the reference value A, the process proceeds to step S7.

In step S7, the pulse width is compared with a predetermined reference value B. As a result, if the pulse width is larger than the predetermined reference value B, it is determined that the speed is low, and the process proceeds to step S8. If the pulse width is smaller than the reference value B, the process proceeds to step S18.

The relationship between the predetermined reference values A and B is always B ≧ A. When the process proceeds from step S7 to step S18, the voltage is not corrected because the pulse width is between the reference value A and the reference value B and the pulse width is appropriate.

First, the control at the time of determining the low speed will be described.

In step S8, load data for judging output data of the current detector 14 as load detecting means is determined. If the load data is equal to or higher than a predetermined level, it is determined that the load is heavy, and the process proceeds to step S9. If the load data is equal to or lower than the predetermined level, the load is determined to be light and the process proceeds to step S11.

In step S9, bs is added to the voltage data.
step is added. This is for accelerating the mechanical system. The voltage data is data stored inside the CPU 10. Next, in step S10,
A voltage is set in the motor driver 13.

If it is determined in step S8 that the load is not heavy, that is, the load is light, in step S11,
The voltage data is corrected only in step. This is because it is not necessary to increase the correction width when the load is light because the response is originally low. Then, step S12
Then, data setting for the motor driver 13 is performed.

Here, the correction amount is the value of bst under heavy load.
“ep” is larger than “step” at the time of light load. This is because if the voltage correction amount is not increased during heavy load, the response of the operation of the mechanical system is deteriorated, and control delay is likely to occur. As a result, smooth control without control delay can be realized.

Next, control at the time of high-speed determination will be described.

In step S13, the load data for determining the output data of the current detector 14 as load detecting means is determined. Here, if the load data is equal to or higher than a predetermined level, it is determined that the load is heavy, and the process proceeds to step S14. If the load data is equal to or lower than the predetermined level, the process proceeds to step S16.

In step S14, the drive voltage data of the motor 15 is corrected. In this case, bstep is subtracted from the voltage data. Next, in step S15, the corrected voltage data is set to the motor driver 13. Thereby, the drive voltage of the motor 15 is corrected.

On the other hand, if it is determined in step S13 that the load is not heavy, that is, the load is light, step S1
In step 6, the step is subtracted from the voltage data. This voltage data is set to the motor driver 13 in the following step S17.

Steps S10, S12, S15, S
When the motor drive voltages are set at 17, respectively, the process shifts to step S18 to determine whether to stop zooming. Here, if it is the stop target position, the process proceeds to step S19, where the brake process is performed and the zoom is stopped.
On the other hand, if it is not the stop target position, the process proceeds to step S4, and the above-described zoom operation is continued.

As described above, in the mechatronics control such as zooming, the feedback correction amount can be varied not only by the conventional pulse width information but also by the load information from the load detecting means, so that the load fluctuation of the mechanical system can be reduced. Regardless, a stable mechanical operation can always be realized.

According to the above embodiment of the present invention,
The following configuration can be obtained.

(1) Driving means for driving the zoom lens, pulse generating means for generating a pulse according to the zoom operation of the zoom lens, and driving voltage control means for controlling the driving voltage of the mechanism driving motor. A pulse width comparison means for comparing a time width of a pulse output from the pulse generation means with a predetermined value; and a load detection means for detecting a load state of the mechanism driving motor. A camera for correcting a motor drive voltage according to an output of a means, wherein a correction width of the motor drive voltage is varied according to load information from the load detection means.

(2) The camera according to (1), wherein the load detecting means detects the load state by comparing a value of a current supplied to the mechanism driving motor with a predetermined value. .

[0045]

As described above, according to the present invention, there is provided a camera capable of always performing optimal control irrespective of ambient conditions and variations in the load of a mechanical system, and achieving both driving speed and stopping accuracy. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a system configuration of a camera according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an external configuration of a camera according to the embodiment of the present invention.

FIGS. 3A and 3B show a state of a photographing lens, where FIG. 3A shows a retracted state, FIG. 3B shows a state extended to a wide end, and FIG. 3C shows a state extended to a tele end; FIG.

FIG. 4 is a timing chart illustrating a photographing operation of the camera according to the embodiment of the present invention.

FIG. 5 is a flowchart illustrating a zoom control operation by CPU 10 of FIG. 1;

[Explanation of symbols]

 1 camera main body, 2 photographing lens, 3 main switch (SW), 4 strobe, 5 zoom switch (SW), 10 CPU, 11 pulse shaping section, 12 pulse generating section, 13 motor driver, 14 current detecting section, 15 motor, 16 Gear train for lens.

Claims (3)

[Claims] 1. A zoom driving means for driving a zoom lens, a pulse generating means for generating a pulse corresponding to a zooming operation by the zoom driving means, and a time width of a pulse output from the pulse generating means being a predetermined value. Pulse width comparing means for comparing; driving voltage control means for controlling a driving voltage of a mechanism driving motor according to an output of the pulse width comparing means; and load state detecting means for detecting a load state of the motor. A camera comprising: a correction range for a drive voltage of the motor that is changed according to load information output from the load detection unit. 2. The camera according to claim 1, wherein the load state detecting means detects a load state of the motor by comparing a value of a current supplied to the motor with a predetermined value. 3. The camera according to claim 2, wherein the load state detecting means is configured to load the motor in a heavy load state when the current value is larger than a predetermined value.