JP2004013028A - Image projection device - Google Patents

Abstract

Provided is an inexpensive image projection apparatus that is easily adjusted for projecting an image on a screen, is easily stored, and is inexpensive.
A DC motor that supplies power, a transmission mechanism that transmits power from the DC motor to a projecting member, an amplifier that supplies a driving current to the DC motor, and a position of the projecting member are detected. When the deviation between the position detector 70 and the position of the protruding member 20 detected by the position detector 70 and the target position to which the protruding member 20 should move is larger than a predetermined value, the drive current is supplied to the DC motor 51. When the deviation is smaller than a predetermined value, the driving current is intermittently applied to the DC motor 51, and when the position of the projecting member 20 reaches the target position, the DC voltage is supplied to the DC motor 51. And a control device 30 that outputs a control command to stop the control to the amplifier 33.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image projection device.
[0002]
[Prior art]
2. Description of the Related Art Some image projection apparatuses such as liquid crystal projectors include an adjuster that changes an elevation angle of an image projection apparatus in order to adjust a height of a projection image on a screen. The adjuster is usually operated by manual operation.
[0003]
[Problems to be solved by the invention]
By the way, when adjusting the height of the projected image on the screen in the image projection device having the adjuster, it is necessary to adjust the amount of expansion and contraction of the feet of the adjuster while lifting the image projection device and viewing the image on the screen. There were disadvantages such as difficult operation and difficult fine adjustment. In addition, every time the position of the screen is changed, it is necessary to adjust the elevation angle of the image projection device, and it takes time to set an image from the image projection device on the screen, and it takes time to store the image. There were disadvantages.
In order to solve the above disadvantage, it is conceivable to make the adjuster electric. However, in order to make the adjuster electric, it is necessary to increase the adjustment accuracy of the adjuster to some extent.
However, increasing the adjustment accuracy of the adjuster requires relatively expensive motors and control circuits such as stepping motors and servomotors, and has the disadvantage of increasing the manufacturing cost of the image projection apparatus.
[0004]
The present invention has been made in view of the above-described problem, and an object of the present invention is to provide an inexpensive image projection device that is easily adjusted for projecting an image on a screen, is easily stored, and is easily stored. .
[0005]
[Means for Solving the Problems]
The present invention is an image projection device for projecting an image, which is an image projection device for projecting an image, wherein the case is inclined about a predetermined axis by projecting a projecting member from a bottom surface of the case, thereby projecting the image. An adjuster for adjusting an elevation angle with respect to a surface, the adjuster including a DC motor for supplying power, a transmission mechanism for transmitting power from the DC motor to the protruding member, and supplying a drive current to the DC motor. A driving circuit, a position detecting means for detecting the position of the protruding member, and a deviation between the position of the protruding member detected by the position detecting means and a target position to which the protruding member should move is larger than a predetermined value. If it is larger, the drive current is continuously supplied to the DC motor, and if the deviation is smaller than a predetermined value, the position of the projecting member reaches the target position. Until a control means for outputting a control command to give intermittently driving current to the DC motor to the drive circuit.
[0006]
In the present invention, when positioning the projecting member at the target position, if the deviation to the target position is large, the drive current is continuously supplied to the DC motor. When the drive current is continuously supplied, the DC motor rotates at a relatively high speed. For this reason, the projecting member also moves at high speed via the transmission mechanism. When the protruding member moves at high speed and approaches the target position, the deviation decreases, and the drive current is intermittently supplied to the DC motor. When the drive current is intermittently supplied to the DC motor, the DC motor rotates at low speed or intermittently, and the projecting member also moves at low speed or intermittently. When the position of the projecting member obtained from the position detecting means reaches the target position, the projecting member stops.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view illustrating an external appearance of an image projection apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image projection device 1 is placed on a base BS, and has a projection opening 2h on a front surface 2a of a cubic case 2.
On the upper surface 2b of the case 2, two operation buttons 5a and 5b and a power switch 6 are provided. These operation buttons 5 a and 5 b and the power switch 6 are arranged near the back surface 2 c of the case 2.
[0008]
On the bottom surface 2d of the case 2, two support members 11 are provided on the front surface 2a side, and a support member 12 is provided on the back side 2c. The case 2 is supported at four points by the support members 11 and 12, and a gap is formed between the base BS and the bottom surface 2 d of the case 2.
[0009]
FIG. 2 is a perspective view showing a state where the image projection device 1 projects an image.
As shown in FIG. 2, the image projection device 1 includes a projecting member 20 that projects from the bottom surface 2d of the case 2.
The operation buttons 5a and 5b are buttons for adjusting the position of the protruding member 20. As will be described later, by operating the operation buttons 5a and 5b, the protruding member 20 is automatically moved up and down.
When the protruding member 20 protrudes from the bottom surface 2 d of the case 2, the protruding member 20 pushes up the case 2, the case 2 inclines around the axis S passing through the support member 12, and the front side 2 a rises from the base BS.
[0010]
FIG. 3 is a diagram for explaining an example of the operation of adjusting the elevation angle of the image projection device 1. As shown in FIG. 3A, a state in which the screen SC as a projection surface is perpendicular to the base BS is defined as an elevation angle of zero degree, and as shown in FIG. 3B, the image projection device 1 is in a horizontal plane. The state in which the angle θ with respect to is set as the elevation angle θ. The elevation angle θ is equal to the angle between the optical axis of the projection lens provided in the case 2 of the image projection device 1 and the direction perpendicular to the screen SC.
The height of the image light L projected from the image projection device 1 on the screen SC is adjusted by changing the elevation angle θ while operating the operation buttons 5a and 5b.
Since the operation buttons 5a and 5b are positioned above the axis S passing through the support member 12, the operation buttons 5a and 5b can be operated while viewing the image projected on the screen SC. Also, even if the image projection device 1 is inclined, as can be seen from FIG. 3B, the positions of the operation buttons 5a and 5b hardly move, so that the operability of the operation buttons 5a and 5b is very good.
[0011]
FIG. 4 is a diagram showing a schematic configuration inside the image projection device 1.
As shown in FIG. 4, the image projection device 1 includes a control device 30, an amplifier 33, a panel drive circuit 34, a lamp power supply 35, a lamp 36, a liquid crystal panel 37, a projection lens 38, and an adjuster mechanism 50. And The control device 30, the amplifier 33, and the adjuster mechanism 50 constitute an adjuster of the present invention.
[0012]
The liquid crystal panel 37 displays an image to be projected on the screen SC.
The panel drive circuit 34 receives a video signal from the input terminal 45 and displays an image based on the video signal.
[0013]
The lamp 36 outputs light for projecting an image displayed on the liquid crystal panel 37.
The lamp power supply 35 supplies power to the lamp 36 according to a control signal from the control device 30.
[0014]
The light from the lamp 36 through the projection lens 38 and the liquid crystal panel 37 is enlarged and emitted to form an image on the screen SC. The above-mentioned opening / closing plate 3 is arranged on the front surface of the projection lens 38. When an image is not projected from the projection lens 38, the opening / closing plate 3 covers the front surface of the projection lens 38 and protects the projection lens 38.
[0015]
FIG. 5 is a perspective view showing the structure of the adjuster mechanism 50 including the configuration of the control device 30.
As shown in FIG. 5, the adjuster mechanism 50 includes a DC motor 51, a projecting member 20, a worm gear 52, a gear 53, a screw shaft 54, and a position detector 70.
[0016]
The worm gear 52 is connected to an output shaft of the DC motor 51 fixed in the case 2.
The gear 53 meshes with the worm gear 52. The center portion of the gear 53 is inserted into the outer periphery of the shaft portion 54b on the upper end side of the screw shaft 54, and is fixed to the shaft portion 54b.
[0017]
The screw shaft 54 includes a screw portion 54 a having a screw formed on the outer periphery. The tip of the shaft portion 54 b of the screw shaft 54 is rotatably supported by a support member 56 fixed in the case 2. The lower end of the shaft 54 is rotatably supported by a support plate 55 fixed in the case 2.
[0018]
The projecting member 20 has upper and lower ends bent, and a screw hole 20h into which the screw portion 54a of the screw shaft 54 is screwed is formed in the upper bent portion.
The protruding member 20 is inserted into a guide hole 55h formed in the support plate 55, and is guided vertically by the guide hole 55h.
[0019]
The protruding member 20 has an arm portion 20A, and the movable portion 71 of the position detector 70 is inserted into an engagement hole 20Ah formed in the arm portion 20A.
[0020]
The position detector 70 outputs a voltage signal corresponding to the position of the movable unit 71 to the control device 30 described above.
As the position detector 70, for example, a potentiometer is used.
[0021]
The control device 30 includes a processor 135, a memory 139, input / output circuits 137, 138, and 140, and an A / D converter 136.
[0022]
The memory 139 stores various data, for example, data such as the previous position of the protruding member 20 and the storage position of the protruding member 20.
[0023]
The input / output circuit 137 outputs to the amplifier 33 a control command 33s1 for driving the DC motor 51 and a control command 33s2 for defining the rotation direction from the processor 135. These control commands 33s1 and 33s2 are low-level and high-level signals.
The input / output circuit 138 inputs an on / off signal 6s from the power switch 6 and command signals 5as and 5bs of the operation buttons 5a and 5b to the processor 135.
The A / D converter 136 converts an analog signal from the position detector 70 into a digital signal and outputs the digital signal to the processor 35.
The input / output circuit 140 outputs an on / off command from the processor 135 to the lamp power supply 35.
[0024]
The processor 135 receives the detection signal 70s of the position detector 70, the on / off signal 6s from the power switch 6, and the command signals 5as and 5bs of the operation buttons 5a and 5b. On and off control and the drive control of the DC motor 51 are performed.
Specifically, when the on / off signal 6 s from the power switch 6 is in the on state, the processor 135 outputs a signal for operating the lamp power supply 35 to the lamp power supply 35, and the on / off signal 6 s In the off state, a signal for turning off the lamp power supply 35 is output to the lamp power supply 35.
When driving the DC motor 51 of the adjuster mechanism 50, the processor 135 outputs to the amplifier 33 a control command 33s1 for driving the DC motor 51 and a control command 33s2 for defining the rotation direction.
[0025]
Amplifier 33 applies, for example, a drive current in a direction corresponding to control command 30s2 to DC motor 51 when control command 30s1 is at a low level, and applies a drive current to DC motor 51 when control command 30s1 is at a high level. Not applied to motor 51. Note that the amplifier 33 is an embodiment of the drive circuit of the present invention.
[0026]
FIG. 6 is a diagram for explaining the operation of the adjuster mechanism 50.
FIG. 6A shows a state in which the protruding member 20 is stored in the case 2 and is at a predetermined storage position.
When the DC motor 51 is driven, the protruding member 20 moves down.
[0027]
When the protruding member 20 is further lowered, the lower end side of the protruding member 20 protrudes from the opening 2e formed in the bottom surface 2d of the case 2, and the lower end of the protruding member 20 reaches the base BS as shown in FIG. I do.
[0028]
When the protruding member 20 is further lowered, as shown in FIG. 6C, the front side of the case 2 is pushed up, and the support member 11 is separated from the base BS.
The tilt angle (elevation angle θ) of the case 2 is adjusted by adjusting the position of the protruding member 20 using the operation buttons 5a and 5b.
[0029]
Next, an example of a series of operations from power-on to power-off of the image projection device 1 having the above configuration will be described with reference to FIG.
FIG. 7 is a flowchart illustrating an example of a series of operations from power-on to power-off of the image projection apparatus 1.
First, the power switch 6 provided on the upper surface 2b of the case 2 is operated to turn on the power to the image projection apparatus 1 (step S1).
When the ON signal 6s is input from the power switch 6, the control device 30 activates the lamp power supply 35 (step S2).
Further, the processor 35 of the control device 30 reads the position information of the protruding member 20 stored in the memory 39 (Step S3). The position information of the projecting member 20 stored in the memory 39 is the position information of the projecting member 20 detected by the position detector 70 at the time of the previous power-off.
[0030]
The control device 30 outputs a control command 30s1 for driving the DC motor 51 and a control command 30s2 for defining the rotation direction to the amplifier 33 based on the read positional information of the protruding member 20.
The control device 30 sequentially obtains the position information of the projecting member 20 that changes as the projecting member 20 descends from the position detector 70, and stores the position information of the projecting member 20 detected by the position detector 70 and the memory 139. The protruding member 20 is moved until it matches the position of the protruding member 20 (step S4).
[0031]
If the protruding member 20 protrudes from the bottom surface 2d of the case 2 at the previous power-off, the protruding member 20 protrudes from the bottom surface 2d of the case 2 again, and the case 2 is tilted so that the elevation angle θ becomes the same as the previous time. I do.
[0032]
After the movement of the projecting member 20 is stopped, an image is projected on the screen SC (Step S5).
In this state, the control device 30 determines whether or not the operation buttons 5a and 5b have been operated to adjust the height of the image displayed on the screen SC (step S6). When the operation buttons 5a and 5b are operated and the command signals 5as and 5bs are input to the control device 30, the control device 30 generates control commands 33s1 and 33s2 based on the command signals 5as and 5bs, and To adjust the position of the protruding member 20 (step S7). Thereby, the height of the image on the screen SC is adjusted.
[0033]
When the controller 30 determines that the power switch 6 has been operated and the off signal 6s has been input from the power switch 6 (step S8), the controller 30 stops the lamp power supply 35 (step S9).
Further, the control device 30 acquires the current position of the projecting member 20 from the position detector 70, and newly stores the position information in the memory 139 (step S10).
[0034]
After storing the position of the projecting member 20 in the one memory 39, the control device 30 reads information on the storage position of the projecting member 20 stored in the memory 139, and based on the read position information, controls the DC motor 51 to the amplifier 33. A driving command 33s1 and a control command 33s2 for defining the rotation direction are output.
The control device 30 sequentially obtains the position information of the projecting member 20 that changes as the projecting member 20 rises from the position detector 70, and stores the position information of the projecting member 20 detected by the position detector 70 and the memory 139. The projecting member 20 is moved until it matches the position of the projecting member 20, and the projecting member 20 is stored in the case 2 (step S11).
[0035]
Next, control of the DC motor 50 by the control device 30 when the projecting member 20 moves from the storage position to the storage position will be described with reference to FIG. This control is performed in steps S3 and S4 shown in FIG.
First, as shown in FIG. 8, the storage position Pb of the protruding member 20 at the time of the previous power-off is acquired from the memory 139 (step S31). This storage position Pb is the target position to which the projecting member 20 should move.
[0036]
Next, the current position Pn of the protruding member 20 is obtained from the position detector 70, and the deviation E between the current position Pn and the storage position Pb is calculated (Step S32).
[0037]
Next, it is determined whether the current position Pn is at the storage position Pb (step S33). This determination is made based on whether the size of the deviation E to a predetermined range of tolerance N ₀ is within. If the deviation E is within a predetermined range of tolerance N _0, it is determined that the current position Pn is equal to the storage position Pb, the process ends.
[0038]
If the deviation E is not within the range of the predetermined tolerance N _0, it is determined whether the current position Pn is far from the storage position Pb is performed (step S34). This determination is made based on a predetermined distance N ₁ which is determined in advance in comparison with the current deviation E.
[0039]
If the deviation E is greater than the distance _{N 1,} the control command 33s1 give the control unit 30 to the amplifier 33 to the low level (step S35). Thereby, the amplifier 33 continuously supplies the drive current to the DC motor 51, and the projecting member 20 moves toward the target position. When the drive current is continuously supplied to the DC motor 51, the DC motor 51 rotates continuously, the protruding member 20 also moves continuously, and moves at a relatively high speed.
[0040]
After the control command 33s1 given from the control device 30 to the amplifier 33 is set to low level, the current position Pn is acquired, and the deviation E is newly calculated (step S36).
Furthermore, the calculated deviation E is determined whether within the range of a predetermined distance N ₁ (step S37). If not subsided calculates the repetition deviation E, performs the determination of whether subsided range of distances N _1.
[0041]
If the deviation E is within a range of a predetermined distance _{N 1,} the control command 33s1 give the control unit 30 to the amplifier 33 to the high level (step S38). As a result, the supply of the drive current to the DC motor 51 is cut off, and the DC motor 51 decelerates. At this time, the control command 33s1 given from the control device 30 to the amplifier 33 is again set to the low level for the predetermined time T ₀ [ms] (step S39). The predetermined time T ₀ is, for example, a very short time of about 10 [ms]. Therefore, since the DC motor 51 that only drive current for a predetermined time T ₀ is supplied, and slightly rotated, the speed is also low.
That is, when the deviation E is within a range of a predetermined distance N _1, since the projecting member 20 can be determined to be approaching the target position, is rotated slowly DC motor 51, the projecting member 20 is the target position To avoid going over.
[0042]
When the control command 33s1 becomes high level again at a low level for the predetermined time T ₀ (ms), and obtains the current position Pn, and calculates a new deviation E (step S40). Furthermore, the calculated deviation E is determined whether within the range of a predetermined distance N ₁ (step S41). If not, it is determined whether or not a predetermined time T ₀ [ms] has elapsed from the time when the control command 33s1 changes from the low level to the high level (step S42).
If the predetermined time T ₀ [ms] has elapsed, the process returns to step S39 and repeats the above processing.
When the process of step S39~S42 are repeated, the control command 33s1 is alternately changed to the low level and the high level at every predetermined time _{T 0} (ms). Therefore, the DC motor 51 rotates intermittently or at a low speed.
In step S41, when the deviation E is within the range of a predetermined distance N _1, the protruding member 20, thereby terminating the process determines that the target position has been reached.
[0043]
Further, in step S34, when the deviation E is smaller than the distance _{N 1} determines that the current position Pn is in a position close to the storage position Pb which is the target position, the process of step S39～S42.
[0044]
As described above, in the present embodiment, the rotational position of the DC motor 51 itself is not detected, and the control command for controlling the DC motor 51 only changes to two states of a low level and a high level. For this reason, it is difficult to accurately control the rotational position and rotational speed of the DC motor 51 itself. Therefore, the position of the protruding member 20 itself is detected, and when the position of the protruding member 20 is far from the target position, the driving current is continuously supplied to the DC motor 51 to move the protruding member 20 to the vicinity of the target position. After that, the drive current is intermittently applied to the DC motor 51 to move the projecting member 20 slowly toward the target position, and when the position of the projecting member 20 reaches the target position, the drive current to the DC motor 51 is reduced. Stop supply.
In addition, since the rotational motion of the DC motor 51 is converted to the linear motion of the projecting member 20 by the transmission mechanism including the worm gear 52, the gear 53, the screw shaft 54, and the like, when the DC motor 51 stops, an external force is applied to the projecting member 20. Even if it acts, since the resistance of the transmission mechanism exists, the projecting member 20 is unlikely to be displaced by the external force.
For these reasons, the projecting member 20 is accurately positioned at the target position. Therefore, when the power of the image projection apparatus 1 is turned on, the previous elevation angle θ is accurately reproduced.
Although the case where the projecting member 20 is positioned at the previous storage position Pb has been described with reference to FIG. 8, when the projecting member 20 is stored, information of a predetermined storage position is stored in the memory 139 instead of the storage position Pb. And performs the same processing as in FIG.
[0045]
As described above, according to the present embodiment, an inexpensive DC motor and simple control are used for the positioning control of the protruding member 20, so that it is possible to suppress an increase in apparatus cost.
Further, according to the present embodiment, when the power is turned on to the image projection apparatus 1, the projecting member 20 for adjusting the elevation angle θ of the image projection apparatus 1 is automatically returned to the position where the power was last shut off. As a result, the preparation work for projecting an image is automatically performed by the image projection apparatus 1, and the time and labor required for the preparation work for each use of the image projection apparatus 1 are greatly reduced.
Further, when the power supply to the image projection device 1 is cut off, the projecting member 20 is automatically stored in a predetermined storage position in the case 2, so that the time and labor required for the storage operation are greatly reduced.
[0046]
Note that the present invention is not limited to the embodiment described above.
In the above-described embodiment, the transmission of the power from the DC motor 51 to the protruding member 20 is described using the transmission mechanism including the worm gear 52, the gear 53, and the screw shaft 54, but without using the worm gear 52, It is also possible to use a gear train composed of spur gears.
[0047]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the adjustment for projecting an image on a screen is easy, the accommodation is easy, and the cheap image projection apparatus is provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of an image projection apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a state where the image projection device 1 projects an image.
FIG. 3 is a diagram illustrating an example of an operation of adjusting an elevation angle of the image projection device 1.
FIG. 4 is a diagram showing a schematic configuration inside the image projection device 1.
FIG. 5 is a perspective view showing the structure of the adjuster mechanism 50.
FIG. 6 is a diagram for explaining the operation of the adjuster mechanism 50.
FIG. 7 is a flowchart illustrating an example of a series of operations from power-on to power-off of the image projection apparatus 1.
FIG. 8 is a flowchart for explaining a control procedure of the DC motor 50 by the control device 30 when the projecting member 20 moves from the storage position to the storage position.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image projection apparatus, 2 ... Case, 2h ... Projection port, 5a, 5b ... Operation switch, 6 ... Power switch, 11, 12 ... Support member, 20 ... Projection member, 30 ... Control device, 33 ... Amplifier, 34 ... Panel drive circuit, 35 lamp power, 36 lamp, 37 liquid crystal panel, 38 projection lens, SC screen, 50 adjuster mechanism, 51 DC motor, 70 position detector.

Claims (1)

An image projection device that projects an image,
By protruding the projecting member from the bottom surface of the case, the case is inclined around a predetermined axis, and an adjuster means for adjusting an elevation angle with respect to the projection surface is provided.
The adjuster means is a DC motor for supplying power,
A transmission mechanism for transmitting power from the DC motor to the projecting member,
A drive circuit for supplying a drive current to the DC motor,
Position detecting means for detecting the position of the projecting member;
When the deviation between the position of the protruding member detected by the position detecting means and a target position to which the protruding member is to move is larger than a predetermined value, a drive current is continuously given to the DC motor, Control means for outputting, to the drive circuit, a control command for intermittently applying a drive current to the DC motor until the position of the projecting member reaches the target position when the deviation is smaller than a predetermined value. Image projection device.

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