JPH10333014A - Zoom lens driving control circuit and method and zoom len incorporated type projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the unnecessary driving of a lens driving means, after a zoom lens is housed and further, the generation of a howl and noise by controlling the lens driving means, with a housed state detecting means. SOLUTION: When the power supply switch 70 of a projector is turned off, a driving control means 40 outputs a driving control signal to the lens driving means 20, to start the housing operation of storing the zoom lens 10 in a projector main body and a counting up operation by a time information calculating means 50. When the fact that the zoom lens 10 becomes a fixed housed state is detected by the housed state detecting means 30, the driving control means 40 allows the zoom lens driving means 20 to stop the operation of housing the zoom lens 10 and stops the counting operation by the time information calculating means 50. Then, the drive control means 40 stores the obtained count value in time information storage means 60. Thus, time information up to the fixed housed state is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control circuit for a zoom lens, a drive control method therefor, and a projection device with a built-in zoom lens, and more particularly, to a liquid crystal display for enlarging and projecting arbitrary image information onto a screen via a zoom lens. The present invention relates to a drive control circuit for a zoom lens used in a projector, a drive control method therefor, and a projection device with a built-in zoom lens.

[0002]

2. Description of the Related Art A liquid crystal projector (also referred to as a projector, hereinafter simply referred to as a projector) 100 includes a "light source" for projecting image information, a liquid crystal panel as "image generating means", and a "projecting means". A projection lens provided with a zoom lens as “”, for example, as shown in FIG. 9, by enlarging and projecting image information from an image information source 101 such as a personal computer or a video onto a screen 102, It is widely used for research presentations, conferences in companies, presentations for education or sales promotion, etc. Such a projector 100 is required to be small, lightweight, excellent in portability or portability, and capable of zoom adjustment of the projection image 103 in order to support projection at different places of use and enlarged projection at different screen sizes. You. Here, when the projector 100 enlarges and projects image information on the screen 102, the zoom is adjusted by driving the motor of the zoom lens 10 manually or by operating a zoom switch.

A zoom lens mounted on a conventional projector and driven by a motor is adjusted by a drive control circuit shown in FIG. In FIG. 10, the zoom lens 10 is driven by a user operating a zoom switch 70. That is, the zoom switch 7 by the user
In response to the operation of 0, zoom-up and zoom-down command signals are input to a central processing unit (hereinafter, referred to as CPU) 80, a drive control signal is output from the CPU 80 to the zoom motor 21, and the zoom lens 10 is held. The expansion and contraction operation of the mold is performed, and the zoom adjustment of the projection image 103 is performed. The user further operates the zoom switch 70 while checking the projected image 103 on the screen 102 to make fine adjustments and set an appropriate screen size.

[0004]

Generally, in a projector with a built-in zoom lens capable of performing an enlarged projection ranging from several tens of inches to several hundreds of inches, the projection of the zoom lens from the projector main body becomes remarkable (5 cm). ,
Or even more) because of the following problems. If the user forgets to store the zoom lens after using the projector, it will not only become an obstacle when transporting or storing the zoom lens in a storage place, but will also be easily damaged. In a projector having a mechanism for driving a zoom lens by a zoom motor, a type in which the zoom lens is automatically housed in the projector body when the power is turned off has been put into practical use. It is necessary to readjust the projected image and operate the zoom switch to readjust the screen size of the projected image, which makes the preparation work of the projector troublesome. In a projector having a mechanism for automatically accommodating the zoom lens by driving the motor when the power is shut off, the zoom motor continues to be driven even after the zoom lens is completely accommodated.

The above problem will be described with reference to FIG. 11 which shows a driving mechanism of a zoom lens provided in a conventional projector. In FIG. 11, a zoom lens 10 has an outer mold 10a and an inner mold 10b in which a lens group constituting a well-known optical system (not shown) is disposed.
A zoom gear 20a provided on the outer periphery of the inner mold 10b; and a flat gear 20b meshing with the zoom gear 20a.
And a zoom motor 21 for driving the spur gear 20b. The rotational motion given by the zoom motor 21 rotates the inner mold 10b via the spur gear 20b and the zoom gear 20a, and the outer mold is rotated with this rotation. The mold 10a protrudes in the direction of arrow A with respect to the projector end face 100a and is housed.

In such a conventional zoom lens driving mechanism, as shown in FIG. 11 (a), the projection size of the zoom lens 10 from the projector end face 100a is maximized (the maximum projection size L _max ). As shown in FIG. 11C, the storing operation is completed, and the
The time required for the protrusion dimension from 0a to reach the minimum (minimum protrusion dimension L _min ) state is defined as the zoom lens storage time T _Z.
Preset as, as shown in FIG. 11 (b), regardless of the projection dimension L _x of the zoom lens 10, a zoom motor 2
1 is driven for a fixed time T _Z , and the state of the zoom lens 10 after the elapse of the time T _{Z is set} to the housed state.

Therefore, the protrusion dimension L of the zoom lens 10
_{When x} is small, storage of the zoom lens 10 takes time T _Z.
However, since the zoom motor 21 is in a driving state until the time _TZ elapses, there is a problem that a humming sound of the zoom motor 21 and an unusual noise due to disengagement between the spur gear 20b and the zoom gear 20a are generated. There is. The present invention
A zoom lens that solves these problems, optimizes the drive time of the zoom motor that houses and drives the zoom lens when the power is turned off, and reduces the adjustment work of the zoom lens by the user when the power is turned on again. It is an object of the present invention to provide a drive control circuit, a drive control method thereof, and a projection device with a built-in zoom lens.

[0008]

According to a first aspect of the present invention, there is provided a zoom lens drive control circuit for enlarging and projecting image information on a screen via a zoom lens. Lens driving means for driving a zoom lens that performs enlargement / reduction adjustment; storage state detection means for detecting a storage state of the zoom lens driven by the lens driving means; Time information calculating means for calculating time information until a predetermined storage state of the zoom lens is detected by the state detecting means; time information storing means for storing the time information calculated by the time information calculating means; The driving state of the lens driving unit is determined based on the time information stored in the time information storage unit and the control signal from the storage state detection unit. It is characterized by having a Gosuru drive control means.

According to such a configuration, the lens driving means can be controlled (stopped) by the storage state detecting means, so that unnecessary driving of the lens driving means after the zoom lens is stored is suppressed. be able to. Therefore, it is possible to suppress the generation of a growling sound and an abnormal noise.
Further, by the storage state detecting means and the time information calculating means,
Time information from the start of the retracting operation of the zoom lens due to the interruption of the power supply to the predetermined retracted state is calculated and stored in the storing means, and the drive control means controls the lens driving means by the time information stored when the power is turned on again. Can be driven, so that the projection dimensions of the zoom lens before the power is turned off, that is, projection conditions such as a projection distance and a screen size of a projection image are calculated and stored as time information, and are stored when the power is turned on again. The previous projection condition can be reproduced by returning the zoom lens to the projection size before the power is turned off based on the time information. Therefore, even when the projector is used in the same place or under similar projection conditions, the user does not have to visually check the image projected on the screen and adjust the zoom every time, and easily sets the use state. be able to.

According to a second aspect of the present invention, in the drive control circuit for a zoom lens according to the first aspect, the storage state detection means includes a storage end detection sensor for detecting an end position of the zoom lens in a storage state. It is characterized by being composed. According to such a configuration, as the storage state detection means, a mechanical switch or a position detection sensor that can directly detect the storage end of the zoom lens can be used. , The shortest time information from the start to the storage end can be calculated, and the drive time of the lens driving means in the storage operation of the zoom lens can be optimized.

According to a third aspect of the present invention, in the drive control circuit for a zoom lens according to the first aspect, the storage state detecting means includes a resistor provided between the lens driving means and a driving power supply. Comparing the potential of the connection point between the lens driving means and the resistor with a preset reference potential,
And a comparator for outputting a signal related to the calculation operation of the time information calculation means in accordance with the result of the comparison.

According to such a configuration, as the storage state detecting means, a voltage detecting resistor for detecting a change in the load state of the lens driving means as a voltage change is provided between the lens driving means and the driving power supply, An increase in the load on the lens driving unit at the storage end of the zoom lens is detected as a voltage change, and the voltage detected by the comparator is compared with a predetermined reference voltage, so that the lens driving unit reaches a predetermined load state. Since it is possible to judge whether or not the operation of calculating the time information can be stopped, it is possible to optimize the driving time of the lens driving unit in the storing operation of the zoom lens.

According to a fourth aspect of the present invention, in the drive control circuit for a zoom lens according to the third aspect, the lens drive means changes the drive current in accordance with the magnitude of a load generated when the zoom lens is driven. It is characterized by being constituted by a motor that operates. According to such a configuration, by using a motor whose drive current amount changes according to the load state generated when the zoom lens is driven as the lens driving unit that drives the zoom lens, the load state in the zoom lens housing operation is Since the amount of drive current changes in response to the above, the change in the amount of current is converted into a change in voltage by a voltage detection resistor, and an increase in the motor load at the storage end of the zoom lens is detected by a comparator. It is possible to optimize the driving time of the lens driving means in the storing operation of (1).

According to a fifth aspect of the present invention, in the drive control method of a zoom lens for enlarging and projecting image information on a screen via a zoom lens, an initial stage adjusted to project an arbitrary enlarged image on the screen is provided. The zoom lens in the state is driven and housed by shutting off the power supply, the calculation of time information is started based on the reference clock, the end of the zoom lens in the housed state is detected, and the driving of the zoom lens is stopped. In addition, the calculation of the time information is stopped and held, and when the power is turned on, the zoom lens is driven based on the held time information to return to the initial state.

According to such a configuration, when the power is turned off,
Calculate and store the storage time from the initial state of the zoom lens whose projected image has been adjusted with the predetermined protrusion size to the storage end,
When the power is turned on again, by projecting the zoom lens for the stored storage time and returning to the initial state, the projection size of the zoom lens immediately before the power is turned off,
That is, since the zoom adjustment condition of the projection image is calculated and held as time information and can be used to reproduce the projection size of the zoom lens when the power is turned on again, the projector can be used at the same location or under similar projection conditions. When using the camera, it is possible to easily return to the previous state of use, reduce the amount of preparation work for adjusting the zoom by viewing the image projected on the screen, and optimize the time required for storing the zoom lens Can be

According to a sixth aspect of the present invention, there is provided a light source for projecting image information, an image generating means for generating the image information, and a zoom for adjusting enlargement and reduction of a projection image projected on a screen by the light source. A projection device having a lens,
A lens driving unit that drives the zoom lens, a storage state detection unit that detects a storage state of the zoom lens driven by the lens driving unit, and the storage unit that starts driving the lens driving unit. Time information calculating means for calculating time information until a predetermined storage state of the zoom lens is detected by the state detecting means; time information storing means for storing the time information calculated by the time information calculating means; Drive control means for controlling a drive state of the lens drive means based on the time information stored in the time information storage means and a control signal from the storage state detection means.

According to such a configuration, since the configuration equivalent to the drive control circuit for the zoom lens according to the first aspect is provided, it is possible to uselessly drive the lens driving unit after the zoom lens is stored. By suppressing the noise, it is possible to suppress the generation of a growling sound and an abnormal noise. Further, time information from the start of the retracting operation of the zoom lens due to the power cutoff to a predetermined retracted state is calculated and stored in the storage unit, and the lens driving unit is driven by the stored time information when the power is turned on again. Therefore, the projection condition of the zoom lens before the power is turned off is calculated and stored as time information, and when the power is turned on again, the zoom lens is returned to the protrusion size before the power is turned off based on the stored time information, The previous projection condition can be reproduced. Therefore, even when the projector is used in the same place or under similar projection conditions, the user does not need to adjust the zoom every time, and the use state can be easily set.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic configuration of a drive control circuit for a zoom lens according to the present invention will be described with reference to FIG. In FIG. 1, reference numeral 10 denotes a zoom lens that performs zoom adjustment for enlarging and reducing a projection image projected on a screen, reference numeral 20 denotes a lens driving unit that drives the zoom lens 10 to adjust the projection image to an arbitrary size, and reference numeral 30 denotes a zoom. The storage state detecting means 40 for directly detecting the storage state of the lens 10 from the mold of the zoom lens 10 or indirectly from the driving state of the lens driving means 20 outputs a drive control signal to the lens driving means 20. A drive control unit that controls a drive state of the zoom lens 10 and controls a time information calculation unit 50 and a time information storage unit 60, which will be described later, based on a detection signal regarding the storage state of the zoom lens output from the storage state detection unit 30; 50 is time information calculating means for performing up-counting and down-counting based on a reference clock; Time information storing means for storing the calculated time information by between information calculating unit, 70 denotes a zoom switch for actuating operation of the zoom lens 10 when performing zoom adjustment of the projection image a user of projector manually.

In this configuration, when the power switch of the projector is shut off, the drive control means 4
0 outputs a drive control signal to the lens driving means 20 to start a storing operation for storing the zoom lens 10 in the projector main body and to start an up-counting operation by the time information calculating means 50. And the zoom lens 10
Has reached the predetermined storage state.
Is detected, the drive control unit 40 causes the zoom lens drive control unit 20 to stop the storing operation of the zoom lens 10 and stop the counting operation by the time information calculation unit 50. Then, the drive control means 40 stores the obtained count value in the time information storage means 60. With such an operation, the count value from the start of the storing operation of the zoom lens 10 due to the power cutoff to the predetermined storing state,
That is, time information is obtained.

Next, when the power switch is turned on, the drive control means 40 retrieves the count value stored in the time information storage means 60 and outputs the count value to the time information calculation means 5.
At the same time, a down-counting operation by 0 is started, and a drive control signal is output to the lens driving means 20 to start a return operation for projecting the zoom lens 10 from the projector main body. Then, the time information calculation means 50
When the counting operation is completed, the drive control unit 40 causes the zoom lens drive control unit 20 to stop the return operation of the zoom lens 10. With such an operation, the zoom lens 1
0 is reproduced in the protruding state before the power is turned off.

Next, FIG. 2 shows a first embodiment of a drive control circuit for a zoom lens according to the present invention, and each circuit configuration will be described with reference to the basic configuration shown in FIG. FIG.
The same components as those described above are denoted by the same reference numerals, and description thereof is omitted. 2, reference numeral 21 denotes a zoom motor for driving the zoom lens 10 by the well-known zoom mechanism shown in FIG. 11 to perform zoom adjustment, and 22 denotes a zoom motor 21.
A motor drive circuit for sending a drive current necessary for driving the zoom motor 21 and the motor drive circuit 2
Reference numeral 2 denotes a lens driving unit 20. Reference numeral 31 denotes a storage position detection sensor, such as a micro switch or a position detection optical sensor, which is attached to the storage end position of the zoom lens 10 and detects the terminal position in the storage operation of the zoom lens. Configure. Also, 80
Controls the operation state of the internal counter based on the end detection signal output by the storage position detection sensor 31, the operation signal from the zoom switch 70, and the operation signal of the power switch (not shown), and controls the motor drive circuit 22 A CPU 51 for sending a drive control command is a clock generation circuit for generating a clock which is a reference for a counter operation inside the CPU 80. The CPU 80 constitutes the drive control means 40 and the time information storage means 60, and
0 and the clock generation circuit 51 constitute the time information calculation means 50.

Next, the internal configuration of the CPU 80 will be described with reference to FIG. 3, reference numeral 52 denotes a counter that performs a counting operation based on a reference clock input from a clock generation circuit 51; 61, a data holding register that stores the count value counted by the counter 52; 41, a storage position detection sensor 31; The counter 52 is instructed to perform an up-count operation or a down-count operation based on the detection signal from the zoom switch 70, the operation signal from the zoom switch 70, and the operation signal from the power switch. And a controller for sending a motor control signal to the motor drive circuit 22 for controlling the drive state of the zoom motor 21.

The internal configuration of the CPU 80 shown in FIG. 3 can use the existing configuration of a normal projector. That is, the CPU of a normal projector controls the number of rotations of a cooling fan, determines the mode of an input image signal, receives a remote control signal, focuses on switching images, performs a zoom adjustment operation, and the like. These configurations are applied as a counter used for the counting operation from the end of the storage operation to the end of the storage operation and a register for storing data.

Next, a drive control method of the zoom lens in the drive control circuit shown in FIGS. 2 and 3 will be described with reference to FIGS. First, the storing operation of the zoom lens will be described with reference to the flowchart of FIG. In a projector at an arbitrary installation location, it is assumed that a user operates a zoom switch in advance, and a zoom lens is in an initial state in which zoom adjustment is performed so that image information is projected on an arbitrary screen size on a screen. . In such an initial state, when the user operates the power switch to turn off the power (S11), this operation signal (power OFF signal) is input to the control unit 41 inside the CPU 80, and the control unit 41 drives the motor. The motor control signal (ON signal) is sent to the circuit 22, and the process of housing the zoom lens 10 in the projector body starts (S12). At this time, the control unit 41
Sends a reset signal to the counter 52 inside the CPU 80, sets the count value to 0 (S13), and starts the up-count operation based on the reference clock from the clock generation circuit 51 (S14). This up-count operation is maintained until the storage position detection sensor 31 detects the storage end, and when the zoom lens 10 reaches the storage end (S15), the storage position detection sensor 31 sends out a detection signal and the control unit 41. From the motor drive circuit 22
Then, the motor control signal (OFF signal) is sent to the zoom lens 10, and the storing process of the zoom lens 10 ends (S16). At this time,
The control unit 41 sends an instruction to stop the count operation to the counter 52 to stop the up-count operation (S17). The count value obtained by this up-counting operation is transferred to the data storage register 61 in the CPU 80 and stored (S18). As a result, a count value corresponding to the required time from the start of the storage operation to the end of the storage operation due to the cutoff of the power is obtained.

Next, regarding the returning operation of the zoom lens,
This will be described with reference to the flowchart of FIG. When the user operates the power switch to turn on the power after the above-described storing operation of the zoom lens is performed (S21),
This operation signal (power ON signal) is input to the control unit 41 inside the CPU 80, and the control unit 41
The previous count value stored in the data storage register 61 inside the U80 is read (S22), and the counter 5
Set the count value to 2. At this time, a motor control signal (ON signal) is sent from the control unit 41 to the motor drive circuit 22 to start a return process in which the zoom lens 10 protrudes from the projector body (S23), and the reference clock from the clock generation circuit 51 , A down-counting operation from the count value is started (S24). This down counting operation is performed by the counter 5
2 is maintained until the count value becomes “0”, and when the count value becomes 0 (S25), the control unit 41 sends a motor control signal (OF) to the motor drive circuit 22.
F signal) is transmitted, and the return processing of the zoom lens 10 ends (S26). Thus, the zoom motor 21 is driven for a time equivalent to the count value counted in the storing operation, and the projection size of the zoom lens 10 reproduces the state at the time of the previous projection, that is, the initial state.

Next, the driving control of the zoom lens according to the present invention will be described.
A second embodiment of the control circuit will be described with reference to FIG.
You. In addition, about the same structure as the above-mentioned 1st Example,
Are denoted by the same reference numerals and description thereof will be omitted. This implementation
The example drive control circuit detects the storage state as shown in FIG.
As means 30, the motor drive circuit 22 and the drive power supply V_A
, A resistor R1 provided between the
The connection point N1 with the resistor R1 is used as one input,
Reference voltage V_RIs the other input, and the output signal is
Output to CPU 80 as a storage end detection signal
Parator 32, output of comparator 32 and high potential power supply
V _DAnd a resistor R2 connected between
I have.

Here, the zoom motor 21 is
Such as induction motors commonly used in motors
A motor that has a drive current value according to the load condition at the time of driving
Has a characteristic that changes. Such a model
By using the data as the zoom motor 21, the zoom
Lens 10 reaches the storage end in the storage operation
The load on the zoom motor 21 increases, and the motor drive circuit
The drive current I sent out from 22 increases. for that reason,
Motor drive circuit 22 and drive power supply V_AProvided between
The driving current I of the zoom motor 21 is connected by the resistor R1
At the point N1, it can be converted into a voltage and taken out.
Then, the voltage change at the connection point N1 and the preset shift
Of the zoom motor 21 at the storage end of the zoom lens 10
Drive current I _RReference voltage V obtained by converting_RAnd compare
The voltage at the connection point N1 is equal to the reference voltage V
_RWhen it becomes smaller, the zoom lens 10 is stored.
Detected as termination state.

That is, the feature of the present embodiment is not the configuration in which the storage end of the zoom lens is directly detected by a microswitch, an optical sensor, or the like, but focuses on the change in the load state when the zoom motor that drives the zoom lens is driven. It is in. The storage operation of the zoom lens when such a storage state detecting means is applied will be described with reference to the flowchart of FIG. 4 and the graph showing the change in the drive current of the zoom motor of FIG.

As in the first embodiment, when the user operates the power switch to cut off the power (S1).
1) The power OFF signal is input to the control unit 41 in the CPU 80, and the control unit 41 sends a motor control signal (ON signal) to the motor drive circuit 22 to start the process of housing the zoom lens 10 in the projector body. (S12). Here, the start time of the storage operation is T ₀ , and the drive current of the zoom motor is I ₀ . At this time, the control unit 41 operates the counter 5 inside the CPU 80.
A reset signal is sent to the counter 2 to set the count value to 0 (S13), and the up-count operation is started based on the reference clock from the clock generation circuit 51 (S1).
4). This up-counting operation is performed until the time when the zoom lens reaches the storage end and the load on the zoom motor 21 increases, and the drive current I reaches a predetermined reference current I _R until time T ₁ , that is, at the connection point N 1 in the comparator 32. is smaller than the voltage reference voltage V _R, housing end detection signal is maintained until the output. When the detection signal is output from the comparator 32 and the control unit 41 recognizes the storage end state of the zoom lens 10 (S1).
5), a motor control signal (OFF signal) is sent from the control unit 41 to the motor drive circuit 22, and the housing process of the zoom lens 10 ends (S16). At this time, the control unit 41 sends an instruction to stop the counting operation to the counter 52 to stop the up-counting operation (S17). The count value obtained by this up-count operation is stored in the data storage register 6 in the CPU 80.
1 and stored (S18). This allows
Count value is obtained which corresponds to the time required from receiving the operation start time T ₀ by power shutdown to the storage operation at the end T _1.

The returning operation of the zoom lens is the same as that of the flowchart shown in FIG. Next, a third embodiment of the drive control circuit according to the present invention will be described with reference to FIG. The same components as those of the above-described second embodiment are denoted by the same reference numerals, and description thereof is omitted.

The drive control circuit according to the present embodiment is different from the drive control circuit shown in FIG. 8 in that the resistor R1, the comparator 32 and the resistor R2 are replaced by a circuit as shown in FIG. 32 and a resistor R2, a resistor R3 provided between the connection point N1 between the resistor R1 and the motor drive circuit 22 and the comparator 32, and a capacitor C provided between the input of the comparator 32 and the ground potential V _GND. And a CR time constant circuit composed of

That is, according to the present embodiment, when the load of the zoom motor 21 is temporarily increased at a position other than the end of the storage during the storing operation of the zoom lens 10, for example, the sliding of the cylindrical molds is performed. The contact state is uneven,
When the frictional resistance increases, the zoom motor 2 shown in FIG.
1, the normal drive current I ₀ becomes equal to or higher than the reference current I _R corresponding to the storage termination state, and the voltage at the connection point N1 increases. However, the CR time constant circuit composed of the resistor R3 and the capacitor C it is possible to suppress an abrupt change of the voltage, to prevent it is prevented that the input to the comparator 32 is equal to or less than the reference voltage V _R, the count value inadvertent stopping count up operation is held be able to.

In the above embodiment, as the storage state detection means, a mechanical switch such as a micro switch, a position detection sensor using an optical sensor, or the like is shown, but the present invention is not limited to these. Further, although the CR time constant circuit is shown as a configuration for suppressing a sudden change in the load state, it goes without saying that another circuit configuration may be used. Further, by providing a changeover switch or the like for setting whether or not to perform a return operation in the drive control circuit of the zoom lens of the present invention, when the projection conditions are completely different, for example, when the previously projected screen size is several hundred inches, On the other hand, in the case where several tens of inches are sufficient for the present use, it is possible to set so as not to execute the returning operation of the zoom lens.

[0034]

As described above, according to the drive control circuit for a zoom lens according to the first aspect, the lens driving means can be controlled (stopped) by the storage state detecting means, so that the zoom lens is stored. Unnecessarily driving the lens driving unit after the operation is performed can be suppressed. Therefore, it is possible to suppress the generation of a growling sound and an abnormal noise. In addition, the storage state detection means and the time information calculation means calculate time information from the start of the storage operation of the zoom lens in response to the cutoff of the power supply to a predetermined storage state, and store the calculated time information in the storage means. Since the lens driving unit can be driven by the time information stored at the time of re-input, the projection size of the zoom lens before power-off, that is, the projection conditions such as the projection distance and the screen size of the projected image are calculated as time information, When the power is stored and when the power is turned on again, the zoom lens is returned to the projection size before the power is turned off based on the stored time information, and the previous projection condition can be reproduced. Therefore, even when the projector is used in the same place or under similar projection conditions, the user does not have to visually check the image projected on the screen and adjust the zoom every time, and easily sets the use state. be able to.

According to the drive control circuit for a zoom lens of the present invention, a mechanical switch or a position detection sensor capable of directly detecting the storage end of the zoom lens can be used as the storage state detecting means. Therefore, it is possible to calculate the shortest time information from the start of the storing operation of the zoom lens to the end of storing when the power is cut off, and it is possible to optimize the driving time of the lens driving unit in the storing operation of the zoom lens.

According to the drive control circuit for a zoom lens according to the third aspect, the load state of the lens driving means is changed between the lens driving means and the driving power source as the storage state detecting means. By providing a voltage detection resistor that detects an increase in the load of the lens driving means at the storage end of the zoom lens as a voltage change, and comparing the voltage detected by the comparator with a predetermined reference voltage,
Since it is possible to determine whether the lens driving means has reached a predetermined load state and to stop the operation of calculating the time information, it is possible to optimize the driving time of the lens driving means in the storage operation of the zoom lens. it can.

According to the drive control circuit for a zoom lens of the present invention, a motor whose drive current varies according to a load state generated when the zoom lens is driven is used as the lens drive means for driving the zoom lens. By doing so, the amount of drive current changes in accordance with the load state in the zoom lens housing operation, so that the change in the amount of current is converted into a change in voltage by the voltage detection resistor, and the voltage at the storage end of the zoom lens is stored by the comparator. By detecting an increase in the motor load, it is possible to optimize the drive time of the lens drive unit in the operation of housing the zoom lens.

Further, according to the drive control method of the zoom lens according to the fifth aspect, when the power is turned off, the storage time from the initial state of the zoom lens, the projection image of which has been adjusted with the predetermined protrusion size, to the storage end is calculated. Hold and when power is turned on again,
Extend the zoom lens for the stored storage time,
By returning to the initial state, the projection size of the zoom lens immediately before the power is turned off, that is, the zoom adjustment condition of the projected image is calculated and held as time information, and used to reproduce the projection size of the zoom lens when the power is turned on again. When using the projector in the same place or under similar projection conditions, it is possible to easily return to the previous use state, and adjust the zoom by viewing the image projected on the screen The preparation work can be reduced, and the time required for storing the zoom lens can be optimized.

According to the projection apparatus with a built-in zoom lens according to the sixth aspect, since it has the same configuration as the drive control circuit of the zoom lens according to the first aspect, it becomes unnecessary after the zoom lens is stored. In this case, it is possible to prevent the lens driving means from being driven at the same time, thereby suppressing the generation of growling noise and abnormal noise. Further, time information from the start of the retracting operation of the zoom lens due to the power cutoff to a predetermined retracted state is calculated and stored in the storage unit, and the lens driving unit is driven by the stored time information when the power is turned on again. Therefore, the projection condition of the zoom lens before the power is turned off is calculated and stored as time information, and when the power is turned on again, the zoom lens is returned to the protrusion size before the power is turned off based on the stored time information, The previous projection condition can be reproduced. Therefore, even when the projector is used in the same place or under similar projection conditions, the user does not need to adjust the zoom every time, and the use state can be easily set.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a basic configuration of a drive control circuit for a zoom lens according to the present invention.

FIG. 2 is a diagram showing a first embodiment of a drive control circuit for a zoom lens according to the present invention.

FIG. 3 is a diagram showing an internal configuration of a CPU applied to a drive control circuit of the zoom lens according to the present invention.

FIG. 4 is a flowchart illustrating a storage operation in the zoom lens drive control method according to the present invention.

FIG. 5 is a flowchart showing a return operation in the zoom lens drive control method according to the present invention.

FIG. 6 is a diagram showing a second embodiment of the drive control circuit for the zoom lens according to the present invention.

FIG. 7 is a diagram showing a change in drive current of a zoom motor of the zoom lens.

FIG. 8 is a diagram showing a third embodiment of the drive control circuit for the zoom lens according to the present invention.

FIG. 9 is a schematic diagram illustrating a projection state of image information by a projector.

FIG. 10 is a diagram showing a drive control circuit of a zoom lens according to the related art.

FIG. 11 is a diagram illustrating a drive mechanism of a zoom lens.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Zoom lens 10a Outer mold 10b Inner mold 20 Lens drive means 20a Zoom gear 20b Flat gear 21 Zoom motor 22 Motor drive circuit 30 Storage state detection means 31 Storage position detection sensor 32 Comparator 40 Drive control means 41 Control unit 50 Time information calculation means 51 Clock generation circuit 52 Counter 60 Time information storage means 61 Data storage register 70 Zoom switch 80 CPU 100 Projector 100a Projector end face 101 Image information source 102 Screen 103 Projected image

Claims (6)

[Claims] 1. A zoom lens drive control circuit for enlarging and projecting image information on a screen via a zoom lens, comprising: a lens drive means for driving a zoom lens for enlarging and reducing a projected image; and a lens drive means. Storage state detection means for detecting the storage state of the driven zoom lens; and time information from the start of driving of the lens driving means to the detection of a predetermined storage state of the zoom lens by the storage state detection means. Time information calculating means for calculating, time information storing means for storing the time information calculated by the time information calculating means, the time information stored in the time information storing means and a control signal from the storage state detecting means Drive control means for controlling a drive state of the lens drive means based on the driving of the zoom lens. Control circuit. 2. The storage state detection means according to claim 1, wherein said storage state detection means comprises a storage end detection sensor for detecting an end position of said zoom lens in a storage state.
A drive control circuit for the zoom lens described in the above. 3. The storage state detecting means includes a resistor provided between the lens driving means and a driving power source, a potential at a connection point between the lens driving means and the resistor, and a preset reference potential. And a comparator for outputting a signal relating to the calculation operation of the time information calculation means in accordance with the result of the comparison. circuit. 4. The zoom lens according to claim 1, wherein said lens driving means comprises a motor whose driving current changes in accordance with the magnitude of a load generated when driving said zoom lens. Drive control circuit. 5. A drive control method of a zoom lens for enlarging and projecting image information on a screen via a zoom lens, comprising: a zoom lens in an initial state adjusted to project an arbitrary enlarged image on the screen; While driving and storing by shutting off, starting calculation of time information based on the reference clock, detecting the end of the zoom lens in the stored state,
Stopping the driving of the zoom lens, stopping and holding the calculation of the time information, and driving the zoom lens based on the held time information by turning on the power to return to the initial state. And a drive control method for the zoom lens. 6. A light source for projecting image information, image generating means for generating the image information, and projecting means having a zoom lens for enlarging and reducing a projection image projected on a screen by the light source. A projection device having a built-in zoom lens, wherein the projection unit drives the zoom lens, a storage state detection unit that detects a storage state of the zoom lens driven by the lens drive unit, Time information calculation means for calculating time information from the start of driving of the lens driving means to the detection of the predetermined storage state of the zoom lens by the storage state detection means; and time information calculated by the time information calculation means. Time information storage means for storing the time information stored in the time information storage means and a control signal from the storage state detection means. And a drive control means for controlling a drive state of the lens drive means based on the control information.