JP2563580B2 - Electric zoom camera - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric zoom camera in which a camera body is integrally provided with an electric zoom lens, and in particular, the operability of the zoom lens is improved by keeping the moving speed constant. The present invention relates to an improved electric zoom camera.

2. Description of the Related Art Conventionally, various electric zoom cameras integrally provided with, for example, an electric zoom lens using a motor as a drive source are known, and the zoom lens in such a camera usually has a wide-angle end based on an operation of an appropriate setting unit. And the telephoto end are continuously moved, and the operation is stopped at the desired position when the operation of the setting means is completed.

At this time, the moving speed of the zoom lens is set to a considerably low speed so that it can be easily stopped at an arbitrary position between the wide-angle end and the telephoto end.

Therefore, for example, when the zoom lens is used between the focal lengths that can be set, the photographer must wait for a considerably long time until either one of the focal lengths is set. It had the inconvenience of missing.

 In other words, it lacked the quick-shooting property.

Moreover, since the movement of the zoom lens is performed only during the operation of the setting means, it is necessary to continue operating the setting means when the moving distance of the zoom lens is long as described above, and it is difficult to say that the operability is excellent. .

Therefore, in recent years, an apparatus as disclosed in JP-A-64-25112 or JP-A-64-70717 has been proposed.

The former has a control means for making the photographing optical system go straight to a first position corresponding to the shortest focal length and a second position corresponding to the longest focal length, and also controls the photographing optical system to the first and second positions. There is disclosed an electric zoom device having a dedicated switch that is operated only when it is desired to go straight.

The latter is a conventionally known first zooming operation in which the focal length of the zoom lens is continuously changed at a relatively slow normal speed only during the operation time of the activation means, and the activation means operates regardless of the length of the operation time. Each time, the zoom lens is driven to a set position set in advance by the stop position setting means at a high speed much higher than the normal speed to instantaneously switch the focal length. Disclosed is a zoom lens drive control device for a camera, which can be set by a zooming operation setting means.

In other words, any of the proposed devices can select the operating state in which the focal length is continuously set and the operating state in which the appropriate focal length is automatically set stepwise. It should be noted that the moving speed of the zoom lens is set to a higher speed in a stepwise operation state than in the continuous operation state.

Therefore, the inconveniences in the quick shooting and operability as described above can be eliminated.

Problems to be Solved by the Invention The above-mentioned two proposed devices are advantageous in terms of quick shooting and operability as compared with conventionally known cameras, but the basic principle of their superiority is the moving speed of the zoom lens. It is clear that there is a point where the variable.

Here, looking at the variable moving speed configuration of the zoom lens in the above two proposed devices, the former is a mechanical mechanism that switches the gear ratio of the transmission gear train in the driving force transmission system between the motor that is the drive source and the zoom lens. On the other hand, the latter is an electrical configuration that switches the energy supplied to the motor, which is the drive source, to the DC supply state or the pulse supply state. The desired effect can be expected.

However, looking at it in more detail, none of the above configurations considers the state of the power source for driving the motor or the zoom lens driven.

That is, no consideration is given to the voltage fluctuation of the power source, the variation of the driving torque of each zoom lens, the difference of the driving torque due to the change of the cam shape of the zoom lens, and the like.

Therefore, in any of the configurations, for example, when the power supply voltage fluctuates, the moving speed of the zoom lens can be set to two speeds, but each set speed itself changes from the speed before the fluctuation of the power supply voltage. It will be.

The fact that the set speed itself changes means that, for example, considering the case where the desired focal length is set while continuously changing the focal length, the operation stop timing of the operating means during movement of the zoom lens is Even if it is the same as before the speed change, the stop position of the zoom lens will be different.

That is, when the power source is consumed and replaced, there is a difference in the focal length setting operation before and after the replacement, and the operability at this point was never good.

The present invention has been made in consideration of the above points, and is provided with speed control means for controlling the moving speed of the zoom lens to a preset speed regardless of the state of the zoom lens and the state of the power supply voltage. It is an object of the present invention to provide an electric zoom camera that further improves the.

Means for Solving the Problems An electric zoom camera according to the present invention includes a motor which is a drive source for moving a zoom lens in an optical axis direction, and an output level between a high level and a low level in response to a moving state of the zoom lens. A lens movement detecting means for generating an output signal that changes alternately; a current speed detecting means for detecting one cycle of the output signal as a current moving speed of the zoom lens;
Comparing means for comparing a preset reference moving speed with the current moving speed, and the driving signal is formed within the one cycle by responding to the output signal, and the driving energy is supplied to the motor in a pulse supply state or Motor drive signal generating means for generating a motor drive signal having a control region set to an appropriate reference period for controlling the non-supply state and an ON region other than the control region for continuously supplying the energy. A motor drive circuit that drives the motor in response to the motor drive signal, and a control unit that controls the supply state of drive energy to the motor by increasing or decreasing the reference period based on the comparison result of the comparison unit. It is configured with.

Action Since the electric zoom camera according to the present invention is configured as described above, when the zoom lens is moved by the motor, its moving speed is detected and compared with a preset reference moving speed.

As a result of comparison, if the current moving speed fluctuates with respect to the reference moving speed due to fluctuations in the power supply voltage, etc., the reference period of the control region in the motor drive signal for controlling the supply state of drive energy to the motor by the control means Will be increased or decreased depending on the fluctuation state.

Therefore, the moving speed of the zoom lens is controlled so that when the current moving speed is faster than the reference moving speed, the reference period is increased, that is, the control region is lengthened and becomes slower.
On the contrary, when the current moving speed is slow, the reference period is reduced, that is, the control area is shortened or eliminated so that the control area is controlled to be faster.

In other words, the moving speed of the zoom lens is controlled based on the current moving speed of the zoom lens. Therefore, the moving of the zoom lens can be performed without being affected by the fluctuation of the power supply voltage and the fluctuation of the load state. You will be able to control the speed.

Example An example of the electric zoom camera of the present invention will be described below.

FIG. 1 is a block diagram showing the configuration of an electric zoom camera according to the present invention. The zoom lens ZL has its focal length variable by moving an appropriate lens group incorporated by a motor 1 in the optical axis L direction. It is designed to be done.

The lens movement detecting means 2 is a zoom lens as described above.
In response to the moving state of ZL, high or low level output signals are alternately output and supplied to the current speed detecting means 3.

The current speed detecting means 3 detects one cycle of the output signal, that is, a high and low level portion or a period consisting of low and high level portions as the current moving speed of the zoom lens ZL, and is appropriately included in the above period, for example. The number of the reference pulse signals is output as current moving speed information and supplied to the comparing means 4.

The comparison means 4 compares the current moving speed information supplied from the current speed detecting means 3 with preset reference moving speed information, that is, in the above-mentioned example, the above-mentioned number indicates the reference moving speed. The number of pulse signals is compared and the comparison result is supplied to the control means 5.

The control means 5 controls the operation of a motor drive signal generation means 6 which will be described later based on the comparison result.

The motor drive signal generating means 6 is formed within the one cycle by responding to the output signal outputted by the lens movement detecting means 2, and supplies the drive energy to the motor in a pulse supply state or a non-supply state. A motor drive signal having a control region to be controlled, which is set in an appropriate reference period, and an ON region other than the control region for continuously supplying the energy is generated and supplied to the motor drive circuit 7. The appropriate reference period is a period that is preset and can be varied, and the variation is performed by the operation of the control means 5.

The motor drive circuit 7 drives the motor 1 in response to the motor drive signal generated by the motor drive signal generation means 6. That is, when the motor drive signal in the control area is supplied, the drive energy is supplied in a pulsed manner to the motor 1 or not, and when the motor drive signal in the on area is supplied, the drive energy is continuously supplied to the motor 1. To work.

Next, the operation of the electric zoom camera according to the present invention having the above-described structure will be described. It is assumed that the current speed detecting means 3 or the motor drive signal generating means 6 is formed by a microcomputer, and the operation shown in FIG. This will be described with reference to the operation flowchart and schematic signal waveform diagram shown in FIG.

Now, when the movement start of the zoom lens ZL is instructed at the time point t ₀ by the operation of the appropriate operation means, the motor drive signal generating means 6 in the microcomputer presets the motor drive circuit 7 and an appropriate reference that can be changed. A motor drive signal as shown in FIG. 3a, which becomes an ON area after the control area having a period has elapsed, is supplied, and the motor 1 is driven.

When the motor 1 is driven, the zoom lens ZL starts moving, while when the zoom lens ZL is moved,
For example, the lens movement detecting means 2 including a photo interrupter operates, and thereafter, a high or low level output signal as shown in FIG. 3B is alternately output in response to the movement state of the zoom lens ZL. Become.

The output signal is supplied to the microcomputer, and its one cycle T ₀ is detected by counting the reference pulse shown in FIG. 3c by the counter in the microcomputer.

At the same time, the motor drive signal, which was in the ON region, is made to be in the OFF region again at the time point t ₁ when the one cycle T ₀ has elapsed.

It goes without saying that the count content M of the counter indicates the current moving speed of the zoom lens ZL, and that M is greater than the same predetermined number R indicating the reference moving speed at step 81 shown in FIG. Are compared.

In the above case, since the zoom lens ZL has just started to move, it is clear that the count content M becomes larger than the predetermined number R, that is, the current moving speed is slower than the reference moving speed, and the flow chart is as follows. In step 82, it is compared whether or not the counted content M is smaller than an arbitrary number N indicating the previous moving speed based on the previous measurement.

Here, the zoom lens ZL has just started moving, that is, it was stopped last time. If 0 is set in advance as the arbitrary number N indicating stop, the flow chart advances to step 83. Become.

In step 83, a value (X-1) obtained by subtracting 1 from the same reference number X as the predetermined number R or the like indicating an appropriate reference period of the control region described above is changed to a new reference number X indicating a new control region period.
Set as.

When the above setting is completed, the flow chart advances to step 84, and it is compared whether or not the set X is larger than 0.

That is, it is determined whether or not the control region can be shortened. If it can be shortened, X is set to 0 directly.
After step 85, proceed to step 86 and step 80
Return to the start.

Therefore, the motor drive signal that has become the control region at time t ₁ should be changed to a signal in which the period of the control region is shortened by the period determined by the previous control region in the unit of the number described above. And is supplied to the motor drive circuit 7 until the next one cycle T ₁ is detected.

Briefly explaining the above operation with the schematic waveform diagram of FIG. 3, for example, the predetermined number R indicating the reference moving speed is 20, the reference number X indicating the preset initial control region period, and the above-mentioned one. Assuming that the count contents M indicating the cycle T ₀ are ₅ and 30, respectively, 20 <30, so the step advances to 81 through 82, and the count contents M 30 is an arbitrary number N indicating the last stopped state. Compared to a certain zero.

Since 0 <30, the step proceeds to 83, 5 which is the reference number X is reduced by 1 and changed to 4, and the next step
At 84, it is confirmed whether or not the above 4 is 0, and since 4> 0, the step returns to 80 of the start through 86.

Therefore, the motor drive signal supplied after the time point t ₁ becomes a signal in which the control region period is shorter than that in the previous case as shown in FIG. 3A, and as a result, the zoom lens ZL
Will be more accelerated.

Thereafter, at time t _{2, the} current moving speed is measured again, and if the count content M is changed to 28 as shown in FIG. 3 due to the acceleration of the zoom lens ZL, the same as in the above case.
Since 28> 20, that is, the current moving speed is also slower than the reference moving speed, the step proceeds to 82.

However, in such a case, 28, which is the counting content M, is smaller than 30, which is the previous moving speed, and therefore the step is 83.
You will not be able to proceed to step 86 but will proceed directly to step 86.

This corresponds to the state where the current moving speed is faster than the previous moving speed when the current moving speed is slower than the reference moving speed and needs to be accelerated, that is, the motor drive signal currently being supplied can accelerate the vehicle. Nothing else, so
In this embodiment, the step 83 for instructing the acceleration is not selected.

Even if the above-mentioned configuration is performed, the previous counting content M indicating the current moving speed of the zoom lens ZL is, for example, one subsequent cycle T ₂ , T ₃ as is clear from FIGS. Also at 26,
It goes without saying that it will decrease to 24.

An appropriate point in time when the movement speed of the zoom lens ZL is accelerated
_If the previous count content M becomes smaller than or equal to the predetermined number R as a result of the comparison in step 81 at t _n , the flow chart advances to step 87, and it is determined whether or not M is larger than an arbitrary number N indicating the previous moving speed. Be compared.

In the case of the previous example, the count content M is 19 as shown in FIG. 3C. In such a case, the count content M is smaller than the arbitrary number N means that the zoom lens ZL It is obvious that the moving speed of the vehicle exceeds the reference moving speed and is about to be further increased. Therefore, needless to say that deceleration is required in this case, the flowchart proceeds to step 88. become.

Step 88 is a value (X + 1) obtained by adding 1 to the reference number X indicating the control area period which has been set and used up to that point.
Is set as a new reference number X. In the case of the above example, 1 is added to the reference number X which was 4 until then.
5 is added to set as a new reference number X.

Then, the flow chart proceeds to step 89, and the new reference number X, for example, 5 is previously set to an appropriate number, for example, 8
Is compared with the maximum value P set to.

When the reference number X is less than the maximum value P, the reference number X is directly set to the maximum value P when the reference number X is greater than or equal to the maximum value P (X
← P) The process proceeds to step 91 through step 90 and returns to the start of step 80.

In the steps 89 and 90, if the reference number X becomes too large, that is, if the control area period of the motor drive signal becomes too long, the moving state of the zoom lens ZL may be intermittent, and such development is prevented. Therefore, this is a step of limiting the reference number X so that it does not exceed an appropriate number.

Therefore, the period of the control area of the motor drive signal after the time point t _n is made longer than the period until then by the period determined by each kind of unit described above, and as a result, the moving speed of the zoom lens ZL is decelerated. Will be done.

After that, the electric zoom camera according to the present embodiment repeats the above-described operation, that is, the control area period of the motor drive signal is changed based on the comparison result between the count content M indicating the current movement speed and the predetermined number R indicating the reference movement speed. The zoom lens ZL is controlled so that the moving speed of the zoom lens ZL is maintained to be delayed near the reference moving speed.

That is, when M = R at the time of comparison between the count content M and the predetermined number R in step 81, the flow chart is such that step 87 is selected.
As will be apparent from the above description, the steps after 87 are steps for reducing the moving speed of the zoom lens ZL, and as a result, the moving speed of the zoom lens ZL is controlled as described above. That is why.

If the content of comparison in step 81 is M ≧ R ?, M =
In the case of R, the flowchart selects step 82. In this case, since each step after step 82 is a step for accelerating, the moving speed of the zoom lens ZL is the reference moving speed contrary to the previous case. Needless to say, the control is performed in the vicinity in a short time, and the flow chart may be configured in this manner.

Similarly, in the comparison in steps 82 and 87, N ≧
By setting R, N ≦ M, the conditions for acceleration and deceleration can be controlled.

The case where the moving speed of the zoom lens ZL normally reaches the reference moving speed has been described above.Next, for example, an arbitrary speed can be reached before the reference moving speed is reached due to a decrease in the power supply voltage as described at the beginning. Described below is the case that is limited to.

In this case, it goes without saying that the flow chart proceeds from step 81 to step 82. On the other hand, since the speed is limited to an arbitrary speed, the relationship between the previous moving speed and the current moving speed in that state becomes equal, that is, N
= M and the result of the comparison in step 82 above
83 will be selected.

Therefore, the reference number X indicating the control area period of the motor drive signal that has been set up to that point is further reduced by one. That is, in the above example, the reference number X, which was 4 until then, is set to 3.

As a result, the driving energy supplied to the motor is further increased, and thereafter, the reference number X as described above is used.
The reduction process can be performed until the reference number X becomes 0, and the movement speed of the zoom lens ZL can be gradually increased by such an operation. Of course, by the time X becomes 0, the relation between M and R, which indicates the current moving speed and the reference moving speed, is M =
If R or M <R, the flow chart goes to step 87 and the subsequent steps.

Even if the current moving speed becomes slower than the previous moving speed without N = M, that is, N <M, step 83 is selected and the same control is performed.

Also. It goes without saying that the above-mentioned X becoming 0 means that the drive energy is continuously supplied to the motor, that is, the zoom lens ZL is moved at the maximum speed currently considered.

The embodiment of the electric zoom camera according to the present invention has been described above. However, since the motor drive signal generating means 6 and the like are formed by a microcomputer, the following developments are possible by utilizing this point.

That is, it is needless to say that it is preferable to control to the reference moving speed in the shortest time possible if it is considered only immediately after the start of the movement of the zoom lens. For example, as shown in FIG. It is considered that if the motor drive signal shown in FIG. 3A is set to a signal only in the ON region until the output signal of the lens movement detecting means 2 elapses from one to several cycles, the above preferable state can be obtained. .

FIG. 4 shows an example of a flowchart for supplying a motor drive signal only in the on-region in an appropriate period at the initial stage of the above-mentioned movement of the zoom lens. This flowchart is based on the operation shown in FIG. 2 described above. It goes without saying that it may be carried out before it is carried out.

The flow chart of FIG. 4 will be briefly described below.

Now, when the movement of the zoom lens ZL is instructed, step 95 for driving the motor 1 is selected, and the driving of the motor 1 is started.

Next, in step 96, the counter C is set to an appropriate value Q (for example, 1 to 5) indicating one to several cycles, and then in step 97, the output signal of the lens movement detecting means 2 is set to one cycle. Whether or not it has passed is detected.

The flow chart does not proceed if the above signal has not passed one cycle,
In step 98, a value obtained by subtracting 1 from the value set in the previous step 96 is set in the counter C as a new counter value.

In the next step 99, it is determined whether or not the new counter value is 0.
Proceeding to 97, the motor 1 is continuously driven by the motor drive signal only in the ON region, and when it is 0, it shifts to another operation mode, for example, the operation mode in which the flowchart shown in FIG. 2 can be carried out.

That is, the motor 1 is continuously driven until the number of cycles set in step 96 elapses, and as a result, the zoom lens is quickly limited to the reference moving speed after the start of the movement. .

As described above, the electric zoom camera according to the present invention manages the moving speed of the zoom lens based on the relationship between the current moving speed of the zoom lens and the reference moving speed.
The moving speed of the zoom lens can be controlled to a speed in the vicinity of the reference moving speed regardless of the fluctuation of the driving torque due to the change of the power supply voltage and the like, and the operability of the focal length setting operation can be improved.

In addition, the operability can be expected to be further improved by expanding the operation mode in which the zoom lens is moved without depending on the relationship between the two speeds only for an appropriate period after the movement of the zoom lens is started.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electric zoom camera according to the present invention, FIGS. 2 and 3 are operation flowcharts and schematic waveform diagrams showing an operation example of the block diagram shown in FIG. 1, and FIG. The flowchart for demonstrating the other operation example of the electric zoom camera by invention is each shown. 1 ... motor, 2 ... lens movement detecting means, 3 ... current speed detecting means, 4 ... comparing means, 5 ... control means, 6 ...
... Motor drive signal generating means, 7 ... Motor drive circuit.

Claims (2)

(57) [Claims] 1. A drive source for moving a zoom lens in an optical axis direction, and a motor and an output signal whose output level alternates between a high level and a low level in response to a moving state of the zoom lens. Lens movement detection means, current speed detection means for detecting one cycle of the output signal as the current movement speed of the zoom lens, comparison means for comparing a preset reference movement speed with the current movement speed, The energy is formed in the one cycle by responding to the output signal and controls the supply of drive energy to the motor to a pulse supply state or a non-supply state. A motor drive signal generating means for generating a motor drive signal having an ON area other than the control area that is continuously supplied; A motor drive circuit that drives the motor in response to a motion signal; and a control unit that controls the supply state of drive energy to the motor by increasing or decreasing the reference period based on the comparison result of the comparison unit. Electric zoom camera. 2. A motor drive signal generating means, before generating a motor drive signal having a control region and an ON region,
The electric zoom camera according to claim 1, wherein the motor drive signal only in the ON region is generated until the output signal output from the lens movement detection means elapses for one to several cycles.