JP2004078161A - projector - Google Patents

Abstract

A projector capable of promptly correcting trapezoidal distortion of a display image without a time lag after determining the installation state of the projector.
Kind Code: A1 Abstract: Adjustment end determination means detects an operation signal accompanying stoppage of depression of a leg adjustment switch for urging adjustment of a tilt of a projector, and determines the end of adjustment of a tilt state. Then, after the adjustment end determination unit 704 determines that the adjustment of the tilt state has ended, the tilt state detection unit 705 calculates the tilt angle of the projector at that time. The correction amount calculating unit 706 calculates a correction value of the display image based on the calculated inclination angle. The display correction unit 707 outputs an image signal of the corrected image to the liquid crystal panel control unit 701 based on the calculated correction value of the display image. Then, the liquid crystal panel control unit 701 drives and controls the liquid crystal panel based on the image signal.
[Selection] Fig. 8

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to distortion correction of a projected image in a projector.
[0002]
[Prior art]
Conventionally, a dichroic mirror that separates a light beam emitted from a light source lamp into three color light beams, three liquid crystal panels that modulate each color light according to image information, and a cross that synthesizes the light beam modulated by each liquid crystal panel There is known a three-plate type projector including a dichroic prism and a projection optical system that displays the combined light beam on a screen.
[0003]
In such a projector, when the projector exists between the observer who observes the projection image and the screen, the projector hinders the observer when observing the projection image. For this reason, it is common to perform tilt projection so that the optical axis of the light beam projected from the projection optical system and the normal direction of the screen make a predetermined angle.
[0004]
However, when the projector is arranged so as to be tilted projection, the image arranged on the screen is enlarged vertically upward from the optical image formed by the liquid crystal panel, and at the upper edge side of the optical image. A trapezoidal distortion (keystone distortion) that has a trapezoidal shape expanded in the horizontal direction occurs. Usually, the projector is provided with a control unit for correcting the trapezoidal distortion, the control unit calculates a correction amount of the trapezoidal distortion, and electrically processes the optical image formed on the liquid crystal panel to correct the trapezoidal distortion. ing. The control unit periodically performs such a trapezoidal distortion correction using a timer at predetermined time intervals.
[0005]
[Patent Document 1]
US Pat. No. 6,481,855
[Patent Document 2]
US Patent No. 6,520,647
[0006]
[Problems to be solved by the invention]
However, when the control unit periodically corrects the trapezoidal distortion using the timer as described above, a time lag occurs until the trapezoidal distortion is corrected by the timer interval. For this reason, there is a problem that the control unit corrects the trapezoidal distortion even while changing the installation state of the projector.
[0007]
SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to quickly correct a trapezoidal distortion of a display image without a time lag after determining a projector installation state.
[0008]
[Means for Solving the Problems and Their Functions and Effects]
The projector of the present invention includes an optical system that modulates a light beam emitted from a light source in accordance with image information to form an optical image and enlarges and projects the same, and a tilt state adjusting mechanism for adjusting a tilt state of the optical system. . According to the present invention, in such a projector, it is determined that the operation of the tilt state adjusting mechanism is completed, the tilt state of the optical system when the operation is determined to be completed is detected, and the distortion of the optical image is corrected based on the tilt state. . By using the end of operation as a trigger for correction, distortion correction can be performed without a time lag after the installation state of the projector is determined. Such distortion correction includes so-called trapezoidal distortion correction.
[0009]
In the present invention, in addition to the function of automatically correcting according to the end of the operation, a function of forcibly performing distortion correction according to the operation of the user regardless of the operation state of the tilt state adjusting mechanism may be provided. By doing so, when the automatic correction is not properly performed due to some trouble, the distortion correction can be easily re-executed. A dedicated switch may be provided as an operation unit for forcibly performing the distortion correction, and for example, a power switch, a focus ring, and the like may also be used.
[0010]
The correction of the distortion can be performed by various procedures. For example, a distortion correction amount of the optical image may be calculated based on the tilt state, and the correction may be performed based on the distortion correction amount. Further, the correction may be performed by using the tilt state as a direct parameter without conversion to the correction amount.
[0011]
In the present invention, the correction may be performed only when the elapsed time from the start of the adjustment is equal to or greater than a predetermined threshold. The elapsed time can be measured, for example, by providing a timer for starting time measurement when it is determined that the adjustment by the tilt state adjustment mechanism has been started. Since the elapsed time when the user operates the tilt adjustment mechanism by mistake is often short, according to this configuration, it is possible to prevent the distortion correction from being performed unintentionally due to the erroneous operation. it can. The threshold value serving as a criterion can be set arbitrarily, and can be set based on, for example, a time required for significantly changing the tilt state of the projector by operating the tilt state adjusting mechanism.
[0012]
In the present invention, when the tilt state adjusting mechanism can be driven by a predetermined power, the end of the operation may be determined by stopping the power. As the power source, for example, a stepping motor or another actuator can be applied. As an example, when the adjustment end determination means includes a variable-length leg for supporting the projector and an adjustment switch for extending and retracting the leg by power, the operation end may be determined by turning off the adjustment switch. it can.
[0013]
When the tilt state adjusting mechanism is provided at a plurality of locations and the support mechanisms for supporting the projector can be individually operated, it may be determined that the operation is completed when the operation on some of the support mechanisms is completed, The operation may be determined to be ended when the operation for all the support mechanisms is completed. According to the latter aspect, it is possible to prevent the distortion from being erroneously corrected before a part of the operation is completed.
[0014]
Examples of the latter include, for example, a housing for housing the optical system in the projector, a plurality of legs that extend and contract from the housing, and a plurality of leg adjustment switches for adjusting the amount of expansion and contraction of each leg. There is a configuration in which it is determined that the adjustment is completed when the adjustment switch is turned off.
[0015]
In the present invention, the tilt state can be detected by various methods. For example, an angle sensor such as a gyro sensor for detecting an inclination angle or an acceleration sensor for detecting acceleration may be used. In the latter case, the inclination angle can be detected by, for example, providing an acceleration sensor in the plane of the substrate horizontally mounted on the projector and detecting a component of the gravitational acceleration that changes according to the inclination angle. In order to ensure accuracy, these sensors are moved to the side opposite to the fulcrum when the projector is tilted, that is, the condition that the distance between the opposite side and the sensor is smaller than the distance between the fulcrum and the sensor. Is preferably provided. The tilt state is not limited to the method using these sensors, and may be calculated based on the operation state of the tilt mechanism. For example, for a tilt mechanism using a leg, the tilt angle can be calculated based on the length of the leg.
[0016]
The present invention can be configured in various modes other than the projector described above, such as a projector control method and a distortion correction method. Further, the present invention may be configured as a computer program for realizing these methods and a recording medium on which the computer program is recorded. Examples of the recording medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punched card, a printed matter on which a code such as a barcode is printed, an internal storage device of a computer (a memory such as a RAM or a ROM) and Various computer-readable media such as an external storage device can be used.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
[1. Main configuration of projector)
FIG. 1 is a perspective view of a projector 1000 as an embodiment viewed from the upper front side. Hereinafter, the device configuration will be described using the up, down, left, right, front and rear directions shown in the drawing. The projector 1000 includes a substantially rectangular parallelepiped housing formed by injection molding of a synthetic resin, that is, an exterior case. The main body of projector 1000 is housed in this outer case. The outer case is configured by combining an upper case 100 and a lower case 200. For example, the left side surface 105 of the upper case 100 and the left side surface 205 of the lower case 200 are continuously connected to form the left side surface of the outer case. The same applies to other aspects.
[0018]
A speaker hole 120 for audio output and an operation panel 110 are provided in front of the upper surface 103 of the upper case 100. When each function button on the operation panel 110 is pressed, a signal corresponding to each function is transmitted to the internal control board. The function buttons can set various functions such as a cooling control function at the time of cooling down, a setting change function of a projection image, an output sound volume adjustment function, and a switching function of input image information.
[0019]
An interface panel 500 is attached to an opening 301 provided on the left side surface 105. The interface panel 500 is provided with connectors 511 and 521 for connecting peripheral devices. These connectors 511 and 521 are respectively connected to a main board and an interface board provided in the outer case.
[0020]
On the left side surface 105, a leg adjustment switch 220 for adjusting the tilt state of the projector 1000 is provided on the front side. The leg adjustment switch 220 is connected to an internal control board, and an operation signal corresponding to pressing / stopping pressing is transmitted to the control board. The operation accompanying the operation of the leg adjustment switch 220 will be described later.
[0021]
On the right side of the front surfaces 101 and 201 of the upper case 100 and the lower case 200, an exhaust port 310 to which a safety cover 311 is attached is formed. A circular opening 302 is formed on the left side of the front surfaces 101 and 201 and near the operation panel 110. A projection lens 460 is arranged in the outer case so that a tip portion protrudes outside from the opening 302. A lever 461 for manually adjusting the focus is provided in a portion where the projection lens 460 protrudes from the outer case.
[0022]
FIG. 2 is a perspective view from the lower rear side of the projector 1000. On the rear surfaces 102 and 202 of the upper case 100 and the lower case 200, a rectangular opening 303 for an inlet connector 304 is formed on the right side.
[0023]
On the lower surface 204 of the lower case 200, a rectangular opening 330 is formed at the right center, and a lamp cover 331 is attached. In the opening 330, a light source lamp is attached to a portion that can be easily replaced when the lamp cover 331 is removed.
[0024]
On the lower surface 204, on the left rear side, an intake port 322 for taking in cooling air from outside is formed in the outer case, and an intake port cover 321 is attached. An opening 320 corresponding to the intake port 322 is formed in the intake port cover 321. The opening 320 is provided with an air filter to prevent dust from entering the inside.
[0025]
A rear leg 221 is provided at a rear center position of the lower surface 204. Further, front legs 222 are provided at the front left and right corners of the lower surface 204, respectively. The projector 1000 is supported at three points by a rear leg 221 and two front legs 222.
[0026]
The front leg 222 is connected to a stepping motor. When the leg adjustment switch 220 described with reference to FIG. 1 is pressed, the stepping motor is driven, and the front leg 222 is expanded and contracted. The stepping motor is driven in the direction in which the leg is extended while the leg adjustment switch 220 is pressed, and after the length of the leg becomes the longest, the operation is reversed to drive in the direction in which the leg is shortened. After the leg length becomes the shortest, the operation is reversed again and the leg is driven in the extending direction. In this embodiment, the leg adjustment switch 220 is used for both extension and contraction of the leg. However, a switch for extension and a switch for contraction may be provided separately. Alternatively, a seesaw type switch or lever may be used so that extension and contraction can be individually instructed according to the manner of operation.
[0027]
When the pressing of the leg adjustment switch 220 is stopped, the switch of the stepping motor is turned off, and the extension and contraction of the front leg 222 is stopped. The posture of the projector 1000, that is, the inclination in the front-back direction and the left-right direction can be adjusted by the expansion and contraction of the front leg 222, and the position of the projection image can be adjusted. When the front leg 222 is extended, tilt projection in which the normal direction of the screen and the optical axis of the light beam projected from the projection lens 460 have a predetermined angle can be realized. Based on this function, the front leg 222 and the leg adjustment switch 220 can be referred to as a tilt adjustment mechanism.
[0028]
A recess 340 for accommodating the remote controller is formed in the front center of the lower surface 204. The recess 340 is provided with a cover 341 that is slidable in the front-rear direction.
[0029]
FIG. 3 is a perspective view in a state where the upper case 100 is removed. A power supply unit 600 is arranged in the outer case in the left-right direction along the back surface.
[0030]
The power supply unit 600 includes a power supply and a lamp drive circuit (ballast) disposed below the power supply. The power supply supplies power externally supplied by a power cable connected to the inlet connector to a lamp driving circuit, a control board, and the like. The lamp driving circuit supplies power supplied from a power source to the light source lamp.
[0031]
The front, rear, and top surfaces of the power supply and the lamp drive circuit are covered with a shield 601 made of metal such as aluminum. The shield 601 has a function as a duct for guiding cooling air, and a function of preventing electromagnetic noise generated in a power supply and a lamp driving circuit from leaking to the outside.
[0032]
The control board is arranged below the metal shield 520. In this embodiment, a main board and an interface board are provided as control boards. The main board has a CPU and a connector 511, and is horizontally arranged below the shield 520. The interface board has a connector 521, and is arranged below the main board along the left side surface.
[0033]
The main board performs various controls described below. For example, it controls a liquid crystal panel included in the optical unit according to image information input via the connectors 511 and 521. The audio data input from the outside is subjected to a predetermined decompression process and output from a speaker. It controls the number of revolutions of the cooling fan, the number, the driving time and the like. Performs trapezoidal distortion correction of the image displayed on the screen.
[0034]
A gyro sensor for detecting the tilt state of the projector 1000 in the front-rear direction, which is necessary for correcting trapezoidal distortion, that is, a gyro sensor, is mounted near the projection lens. A specific illustration of the gyro sensor is omitted. The gyro sensor may be capable of detecting not only the tilt angle but also the tilt state in the left-right direction, ie, the roll angle.
[0035]
The detection of the tilt angle is not limited to the gyro sensor, and various rotation angle sensors, for example, a sensor using electromagnetism, resistance change, light, or the like can be adopted. The tilt angle may be calculated according to the extension amount of the front leg 222.
[0036]
FIG. 4 is a perspective view showing a state where the shield 520 and the control board are removed. As illustrated, an optical unit 400 having a substantially L-shape in plan view is disposed in front of the power supply unit 600. The main board described above is arranged so as to contact the upper end portion 482 of the upper light guide 481 of the optical unit 400.
[0037]
[2. Detailed configuration of optical unit)
FIG. 5 is an explanatory diagram showing a schematic configuration of the optical unit 400. The optical unit 400 is a unit that enlarges and projects an optical image formed by modulating a light beam emitted from the light source device 411 according to image information. The optical unit 400 includes an integrator illumination optical system 410, a color separation optical system 420, a relay optical system 430, an optical device 440, and a projection lens 460.
[0038]
The integrator illumination optical system 410 is an optical system for almost uniformly illuminating the image forming areas of the three liquid crystal panels 441R, 441G, and 441B corresponding to red, green, and blue color lights, respectively. A first lens array 412, a second lens array 413, a polarization conversion element 414, and a superimposing lens 415 are provided. Hereinafter, the liquid crystal panels 441R, 441G, and 441B may be collectively referred to as a liquid crystal panel 441.
[0039]
The light source device 411 includes a light source lamp 416 as a radiation light source and a reflector 417. The light beam emitted from the light source lamp 416 is reflected by the reflector 417 and emitted to the outside as a parallel light beam. A high-pressure mercury lamp is used as the light source lamp 416. Metal halide lamps and halogen lamps can be used. The reflector 417 employs a parabolic mirror. A combination of a parallelizing concave lens and an ellipsoidal mirror may be employed.
[0040]
The first lens array 412 has a configuration in which small lenses having a substantially rectangular outline when viewed from the optical axis direction are arranged in a matrix. Each small lens divides a light beam emitted from the light source lamp 416 into a plurality of partial light beams. The outline shape of each small lens is substantially similar to the shape of the image forming area of the liquid crystal panel 441. For example, if the aspect ratio (the ratio between the horizontal and vertical dimensions) of the image forming area of the liquid crystal panel 441 is 4: 3, the aspect ratio of each small lens is also 4: 3.
[0041]
Like the first lens array 412, the second lens array 413 has a configuration in which small lenses are arranged in a matrix. The second lens array 413 forms an image of each small lens of the first lens array 412 on the liquid crystal panel 441 together with the superimposing lens 415.
[0042]
The polarization conversion element 414 is disposed between the second lens array 413 and the superimposing lens 415. The polarization conversion element 414 converts the light from the second lens array 413 into one type of polarized light. Each partial light converted by the polarization conversion element 414 is superimposed on the liquid crystal panel 441 by the superimposing lens 415. Although the liquid crystal panel can use only one kind of polarized light, the function of the polarization conversion element 414 can convert various kinds of polarized light emitted from the light source lamp into one kind, thereby improving light use efficiency. Can be. Such a polarization conversion element 414 is disclosed, for example, in JP-A-8-304739.
[0043]
The color separation optical system 420 includes two dichroic mirrors 421 and 422 and a reflection mirror 423, and converts partial light beams emitted from the integrator illumination optical system 410 into red (R), green (G), and blue (B). Into three color lights.
[0044]
The dichroic mirror 421 transmits red light and green light and reflects blue light in the light flux emitted from the integrator illumination optical system 410. The reflected blue light is reflected by the reflection mirror 423, passes through the field lens 418, and reaches the blue liquid crystal panel 441B.
[0045]
The dichroic mirror 422 selectively reflects green light. Therefore, of the light transmitted through the dichroic mirror 421, the green light is reflected by the dichroic mirror 422, passes through the field lens 418, and reaches the liquid crystal panel 441G for green. The red light passes through the dichroic mirror 422, passes through the relay optical system 430, further passes through the field lens 418, and reaches the liquid crystal panel 441R for red light.
[0046]
The field lens 418 converts each partial light beam emitted from the second lens array 413 into a light beam parallel to its central axis (principal ray). The same applies to the field lens 418 provided on the light incident side of the other liquid crystal panels 441G and 441R.
[0047]
As described above, the relay optical system 430 guides red light to the liquid crystal panel 441R by the incident side lens 431, the relay lens 433, and the reflection mirrors 432 and 434. The relay optical system 430 has a function of preventing a decrease in light use efficiency due to divergence of light in the process of transmitting a partial light beam incident on the incident side lens 431 to the field lens 418. The reason why the relay optical system 430 is used for the red light is that the length of the optical path of the red light is longer than the length of the optical paths of the other color lights, and light diverges easily. Instead of the illustrated configuration, a configuration may be adopted in which a color other than red light, for example, blue light is passed through the relay optical system 430.
[0048]
The optical device 440 modulates the incident light beam according to image information to form a color image. The optical device 440 includes three incident-side polarizing plates 442 on which the respective color lights separated by the color separation optical system 420 enter. A liquid crystal panel 441R, 441G, 441B as a light modulation device disposed at a stage subsequent to each of the incident-side polarizing plates 442; A cross dichroic prism 444 as an optical system is provided.
[0049]
The liquid crystal panels 441R, 441G, and 441B use, for example, polysilicon TFTs as switching elements.
[0050]
The incident-side polarizing plate 442 transmits only polarized light in a certain direction among the color lights separated by the color separation optical system 420, and absorbs other light beams. For example, a polarizing film may be attached to a substrate such as sapphire glass, or a polarizing film may be attached to the field lens 418 without using a substrate.
[0051]
Similarly to the incident-side polarizing plate 442, the exit-side polarizing plate 443 transmits only polarized light in a predetermined direction among the light beams emitted from the liquid crystal panel 441, and absorbs other light beams. The emission-side polarizing plate 443 may be configured by attaching a polarizing film to the cross dichroic prism 444.
[0052]
The incident-side polarizing plate 442 and the exit-side polarizing plate 443 are set such that the directions of the polarization axes are orthogonal to each other.
[0053]
The cross dichroic prism 444 forms a color image by combining optical images emitted from the emission-side polarizing plate 443 and modulated for each color light. The cross dichroic prism 444 includes a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light because the three color lights are combined. It is provided in.
[0054]
FIG. 6 is a perspective view of the optical device 440. The liquid crystal panel 441, the emission-side polarizing plate 443, and the cross dichroic prism 444 described above are assembled as one unit called an optical device 440.
[0055]
In the optical device 440, a fixing plate 447 made of a synthetic resin is fixed on the upper surface of the cross dichroic prism 444. The four arms 447A of the fixing plate 447 are provided with round holes 447B used for fixing the optical device 440 with screws.
[0056]
A metal holding plate 446 that holds the emission-side polarizing plate 443 is attached to the light-incident end face of the cross dichroic prism 444. Four pins 445 made of transparent resin are attached to the holding plate 446 on the light incident side, and the liquid crystal panels 441R, 441G, and 441B are held by the pins 445. A predetermined gap is provided between the holding plate 446 and the liquid crystal panel 441 to allow cooling air to flow.
[0057]
FIG. 7 is an exploded perspective view of the optical unit 400. The optical unit 400 includes a lower light guide 471 that is substantially L-shaped in plan view, and a lid-like upper light guide 481 that closes an upper opening of the lower light guide 471. Each of the optical components described with reference to FIGS. 5 and 6 is slidably fitted into a groove provided in the lower light guide 471 from above.
[0058]
One end of the lower light guide 471 accommodates the light source device 411. A projection lens 460 is screwed and fixed to the other end via a head unit 473.
[0059]
The optical device 440 is screwed and fixed to the lower light guide 471 via the spring 483 of the upper light guide 481. The two springs 483 urge the field lens 418 and the incident side polarizing plate 442 downward.
[0060]
[3. Control unit structure)
FIG. 8 is a block diagram schematically showing the structure of the control unit 700. In the present embodiment, the control unit 700 is configured on a main board as a microcomputer including a CPU, a RAM, a ROM, and the like. Each unit of the control unit 700 may be configured as software or may be configured as hardware by causing a CPU to execute a control program stored in a ROM or the like.
[0061]
FIG. 8 mainly shows a function for performing trapezoidal distortion correction, and omits other control function blocks. In the figure, a gyro sensor 710, a liquid crystal panel 441, and a leg adjustment switch 220 are also shown as modules for transmitting and receiving signals to and from the control unit 700 in order to realize such control.
[0062]
The liquid crystal panel control unit 701 drives and controls the liquid crystal panel 441 according to image information input from the outside. In the present embodiment, the liquid crystal panel control means 701 is constituted by an image signal processing circuit on which circuit elements such as a CPU and a memory are mounted.
[0063]
The adjustment start determining unit 702 detects the pressing of the leg adjustment switch 220, and when pressed, determines that the adjustment of the tilt state of the projector 1000 has been started. Then, when it is determined that the adjustment has been started, the adjustment start determination unit 702 outputs an instruction to start measurement of the elapsed time to the timer 703.
[0064]
The adjustment end determination unit 704 detects that one of the leg adjustment switches 220 provided on the left and right is stopped being pressed, and determines that the adjustment of the tilt state of the projector 1000 has been completed when the pressed stop is detected. . Then, when it is determined that the adjustment has been completed, the adjustment end determination unit 704 outputs a measurement end instruction to the timer 703 during the elapsed time.
[0065]
The timer 703 measures the adjustment period of the tilt state of the projector 1000, that is, the elapsed time from the measurement start instruction by the adjustment start determination unit 702 to the measurement end instruction by the adjustment end determination unit 704. If the elapsed time is equal to or greater than the predetermined threshold value t, the timer 703 outputs a tilt state detection instruction to the tilt state detection unit 705. The threshold value t can be set arbitrarily. For example, the threshold value t can be set on the basis of the time required from the start of operation of the leg adjustment switch 220 until a significant change in the tilt state appears.
[0066]
The tilt state detecting means 705 calculates a tilt angle based on a sensor signal from the gyro sensor 710 according to a detection instruction from the timer 703. Further, the tilt state detecting means 705 outputs the calculated tilt angle to the correction amount calculating means 706.
[0067]
The correction amount calculation unit 706 calculates a correction value for correcting keystone distortion based on the tilt angle. The display correction unit 707 generates a corrected pixel signal obtained by performing trapezoidal distortion correction on image information input from the outside based on the correction value, and outputs the corrected pixel signal to the liquid crystal panel control unit 701.
[0068]
[4. Keystone distortion correction method)
FIG. 9 is a flowchart of the trapezoidal distortion correction processing. This process is repeatedly executed by the control unit 700 during the projection of an image. When this process is started, the adjustment start determining means 702 determines the start of adjustment of the tilt state (step S101). When the user presses the leg adjustment switch 220 to extend and retract the front leg 222, it is determined that the adjustment of the tilt state has been started.
[0069]
When the adjustment is started, a measurement start instruction is output from the adjustment start determination unit 702 to the timer 703, and the timer 703 starts measuring the elapsed time (step S102).
[0070]
Next, the adjustment end determination means 704 determines the end of the adjustment of the inclined state (step S103). When the user stops pressing the leg adjustment switch 220, it is determined that the adjustment of the inclined state has been completed. When the adjustment is completed, a measurement end instruction is output from the adjustment end determination unit 704 to the timer 703, and the timer 703 ends the measurement of the elapsed time.
[0071]
The timer 703 compares the elapsed time thus measured with a predetermined threshold value t (step S104). If the elapsed time is equal to or less than the threshold value t, the control unit 700 determines that pressing the leg adjustment switch 220 is caused by an erroneous operation, and restarts the process from the beginning. If the elapsed time is greater than the threshold value t, the control unit 700 determines that the adjustment of the tilt state is completed, and outputs a tilt state detection instruction to the tilt state detection unit 705.
[0072]
The tilt state detecting means 705 inputs the detection result of the gyro sensor 710 in response to the tilt state detection instruction, and calculates a tilt angle, that is, a tilt angle (step S105). The correction amount calculation unit 706 calculates a correction value of the trapezoidal distortion image based on the tilt angle (step S106). The display correction unit 707 performs keystone distortion correction based on the correction value (Step S107).
[0073]
FIG. 10 is an explanatory diagram of a method of calculating a correction value. In the upper part of the figure, the distorted image A projected when tilt-projection is performed is shown by a solid line, and the normal image B projected when tilt-projection is not performed is shown by a broken line.
[0074]
An image formed on the liquid crystal panel 441 is schematically shown below the figure. In order to correct the distortion of the distortion image A and project an image equivalent to the normal image B, an image C distorted in a shape opposite to that of the distortion image A may be formed on the liquid crystal panel 441. The image C distorted in this way is called an effective image C, and its surroundings are called an invalid image D.
[0075]
The correction amount calculating unit 706 calculates a correction value indicating a positional relationship between an arbitrary pixel FP2 in the projected image and a pixel FP1 corresponding to the pixel FP2 in the corrected image based on the tilt angle. The display correction unit 707 gives a pixel signal of the pixel FP2 on the original image information to an arbitrary pixel FP1 of the effective image C specified based on the correction value. Further, a pixel signal representing black is given to a pixel corresponding to the invalid image portion D. By outputting the pixel signals corrected in this way to the liquid crystal panel control unit 701, trapezoidal distortion correction is realized.
[0076]
[5. Effect of First Embodiment]
According to the first embodiment, the following effects are obtained.
(1) The correction of the distorted image is automatically performed after it is determined that the adjustment of the tilt state of the projector 1000 has been completed. Therefore, it is possible to correct the distorted image without a time lag after determining the tilt state of the projector 1000.
[0077]
(2) In the embodiment, when the elapsed time from the start of the adjustment is larger than the predetermined threshold value t, the distortion image is corrected. This can prevent the distortion image from being erroneously corrected when the user presses the leg adjustment switch 220 by mistake.
[0078]
(3) The tilting state of the projector 1000 can be easily adjusted with a simple structure by a mechanism for expanding and contracting the front leg 222 in response to the pressing of the leg adjustment switch 220.
[0079]
(4) Since the leg adjustment switch 220 and the front leg 222 are separately provided on the left and right, not only the inclination of the projector 1000 in the front-rear direction but also the horizontal inclination can be implemented.
[0080]
[Second embodiment]
Next, a second embodiment of the present invention will be described. In the first embodiment, an example has been described in which when the operation of at least one of the left and right leg adjustment switches 220 is completed, it is determined that the adjustment of the inclined state has been completed, and the distortion image is corrected. The second embodiment exemplifies a case where the distortion image is corrected when the operation of both leg adjustment switches 220 is completed. In the second embodiment, it is assumed that the same number of timers 703 as the number of the leg adjustment switches 220 are provided in order to individually measure the elapsed time from the start of pressing each leg adjustment switch 220.
[0081]
FIG. 11 is a flowchart of a trapezoidal distortion correction process according to the second embodiment. When this process is started, the adjustment start determining means 702 determines whether any of the leg adjustment switches 220 is on (step S111). When any one of the leg adjustment switches 220 is turned on, the timer 703 corresponding to the leg adjustment switch 220 starts measuring the elapsed time in response to an instruction from the adjustment start determining means 702 (step S112).
[0082]
When there is the leg adjustment switch 220 turned off (step S113), the adjustment end determination unit 704 ends the measurement of the elapsed time by the timer 703 corresponding to the switch. The timer 703 compares the elapsed time with a predetermined threshold value t (step S114). If the elapsed time is equal to or less than the predetermined threshold value t, the timer 703 determines that the leg adjustment switch 220 has been erroneously operated, and proceeds from step S111. Is restarted.
[0083]
If the elapsed time is greater than the predetermined threshold value t, the timer 703 determines that the operation of the leg adjustment switch 220 has ended. The adjustment end determination unit 704 repeatedly executes the above processing until the operation is completed for all the leg adjustment switches 220 determined to be on in S111 (step S115).
[0084]
When the operation of all the leg adjustment switches 220 is completed, the control unit 700 calculates the inclination angle (step S116), calculates the correction value of the distortion image (step S117), and calculates the distortion image, as in the first embodiment. Correction (step S118) is performed.
[0085]
According to the above-described second embodiment, the following effects are obtained in addition to the effects of the first example. That is, since the distortion image is corrected only when the operation of all the leg adjustment switches 220 has been completed, the distortion correction may be performed erroneously before the operation of one of the leg adjustment switches 220 is completed. Can be avoided.
[0086]
[6. Modification)
In the embodiment, the example in which the distortion image is corrected when the elapsed time is larger than the threshold value t has been described. However, the distortion correction may be performed regardless of the elapsed time. In addition to the automatic correction accompanying the end of the adjustment of the tilt state, the correction may be forcibly executed by a user operation.
[0087]
In the embodiment, the number of the leg adjustment switches 220 and the number of the front legs 222 are two, but various settings such as one or three or more are possible. Also, a plurality of front legs 222 may be extended and contracted in conjunction with one leg adjustment switch 220.
[0088]
The number of liquid crystal panels of the projector 1000 is not limited to three, but may be one, two, or four or more. The liquid crystal panel may be either a transmission type or a reflection type. The light modulation device is not limited to a liquid crystal panel, and various devices such as a device using a micromirror can be applied.
[0089]
In the embodiment, the front type projector that projects from the front of the screen is illustrated, but the present invention is also applicable to a rear type projector that projects from the back of the screen.
[Brief description of the drawings]
FIG. 1 is a perspective view of a projector 1000 as an embodiment viewed from an upper front side.
FIG. 2 is a perspective view of the projector 1000 as viewed from the lower rear side.
FIG. 3 is a perspective view showing a state where an upper case 100 is removed.
FIG. 4 is a perspective view showing a state where a shield 520 and a control board are removed.
FIG. 5 is an explanatory diagram showing a schematic configuration of an optical unit 400.
FIG. 6 is a perspective view of an optical device 440.
FIG. 7 is an exploded perspective view of the optical unit 400.
FIG. 8 is a block diagram schematically showing a structure of a control unit 700.
FIG. 9 is a flowchart of a trapezoidal distortion correction process.
FIG. 10 is an explanatory diagram of a method for calculating a correction value.
FIG. 11 is a flowchart of a trapezoidal distortion correction process according to a second embodiment.
[Explanation of symbols]
1000 ... Projector
100 ... upper case
101, 201 ... front
102, 202 ... back
103 ... upper surface
105 ... left side
110 ... Operation panel
120 ... Speaker hole
200… Lower case
204 ... lower surface
205 ... left side
220 ... Leg adjustment switch
221… hind leg
222 ... front leg
301, 302, 303 ... opening
304… Inlet connector
311 ... Safety cover
310 ... exhaust port
320 ... opening
321 ... intake port cover
322 ... intake port
330 ... opening
331 ... Lamp cover
340: recess
341 ... cover
400 Optical unit
460: Projection lens
461 ... Lever
481 ... Upper light guide
482: upper end
411: Light source device
410 ... Integrator illumination optical system
420: color separation optical system
430 relay optical system
440 ... Optical device
412: first lens array
413: second lens array
414 ... polarization conversion element
415 ... Superimposed lens
416 ... light source lamp
417 ... Reflector
418 ... Field lens
421,422 ... Dichroic mirror
423 ... Reflection mirror
431 ... incident side lens
432, 434 ... Reflection mirror
433 ... Relay lens
441, 441B, 441R, 441G ... liquid crystal panel
442... Incident side polarizing plate
443: Polarizing plate on emission side
444 ... Cross dichroic prism
445 ... pin
446: Holding plate
447 ... Fixed plate
447A ... arm
447B: Round hole
471 ... Lower light guide
473… Head part
483 ... spring
500 ... Interface panel
511, 521 ... connector
520 ... Shield
600 Power supply unit
601… Shield
700 ... Control unit
701: LCD panel control means
702... Adjustment start determining means
703 ... Timer
704: Adjustment end determination means
705: tilt state detecting means
706... Correction amount calculating means
707... Display correction means
710 ... Gyro sensor

Claims (21)

A projector,
An optical system that modulates a light beam emitted from a light source in accordance with image information to form an optical image, and enlarges and projects;
An inclination adjustment mechanism for adjusting the inclination of the optical system,
Adjustment end determining means for determining the end of operation on the tilt state adjusting mechanism;
Tilt state detection means for detecting the tilt state of the optical system when it is determined that the operation has been completed,
A projector comprising: a display correction unit configured to correct distortion of the optical image based on the detected tilt state. The projector according to claim 1, wherein
A correction amount calculating unit that calculates a distortion correction amount of the optical image based on the tilt state,
A projector configured to perform the correction based on the distortion correction amount. The projector according to claim 1, wherein
A time measuring means for measuring an elapsed time from the start of adjustment by the tilt state adjusting mechanism,
The projector, wherein the display correction unit performs the correction when the elapsed time is equal to or greater than a predetermined threshold. The projector according to claim 1,
The tilt state adjusting mechanism can be driven by a predetermined power,
The projector, wherein the adjustment end determination unit determines the end of the operation by stopping the power. The projector according to claim 1, wherein
The tilt state adjusting mechanism,
A variable-length leg for supporting the projector;
An adjustment switch for extending and retracting the legs by the power,
The projector, wherein the adjustment end determination unit determines the operation end by turning off the adjustment switch. The projector according to any one of claims 1 to 5,
The tilt state adjusting mechanism is provided at a plurality of locations, and can individually operate a supporting mechanism for supporting the projector,
The projector, wherein the adjustment completion determination unit determines that the operation has been completed when the operation on all of the plurality of support mechanisms is completed. The projector according to claim 1,
The projector, wherein the tilt state detecting means is an angle sensor or an acceleration sensor provided near a side opposite to a fulcrum when the projector is tilted. A projector control method comprising: an optical system that modulates a light beam emitted from a light source according to image information to form an optical image to project an enlarged image, and an inclination state adjustment mechanism that adjusts an inclination state of the optical system. So,
An adjustment end determination step of determining an operation end for the tilt state adjustment mechanism,
An inclination detection step of detecting an inclination state of the optical system when it is determined that the operation has been completed,
A display correction step of correcting distortion of the optical image based on the detected tilt state. The control method according to claim 8, wherein
A correction amount calculating step of calculating a distortion correction amount of the optical image based on the tilt state,
The display correction step is a control method for performing the correction based on the distortion correction amount. The control method according to claim 8 or 9,
Comprising a timing step of measuring the elapsed time from the start of adjustment by the tilt state adjustment mechanism,
The control method, wherein the display correction step performs the correction when the elapsed time is equal to or greater than a predetermined threshold. The control method according to any one of claims 8 to 10,
The tilt state adjusting mechanism can be driven by a predetermined power,
The adjustment termination determining step is a control method for determining the termination of the operation by stopping the power. The control method according to any one of claims 8 to 11,
The tilt state adjusting mechanism,
A variable-length leg for supporting the projector;
An adjustment switch for extending and retracting the legs by the power,
The control termination determining step is a control method for determining the termination of the operation by turning off the adjustment switch. The control method according to any one of claims 8 to 12,
The tilt state adjusting mechanism is provided at a plurality of locations, and can individually operate a supporting mechanism for supporting the projector,
The adjustment end determination step is a control method for determining that the operation has ended when the operation on all of the plurality of support mechanisms has ended. The control method according to any one of claims 8 to 13,
The tilt state detecting step is a control method of detecting the tilt state based on an output value of an angle sensor or an acceleration sensor provided near a side facing a fulcrum when the projector is tilted. To control a projector including an optical system that modulates a light beam emitted from a light source in accordance with image information to form an optical image to project an enlarged image, and an inclined state adjusting mechanism that adjusts an inclined state of the optical system. Computer program,
An adjustment end determination function for determining an operation end for the tilt state adjustment mechanism,
An inclination detection function for detecting an inclination state of the optical system when it is determined that the operation has been completed,
A computer program implemented by a computer and a display correction function for correcting distortion of the optical image based on the detected tilt state. A computer program according to claim 15, wherein
Based on the tilt state, the computer realizes a correction amount calculation function of calculating a distortion correction amount of the optical image,
A computer program for performing the correction based on the distortion correction amount. The computer program according to claim 15 or 16,
Implemented by the computer a clock function for measuring the elapsed time from the start of adjustment by the tilt state adjustment mechanism,
A computer program for performing the correction when the elapsed time is equal to or greater than a predetermined threshold. The computer program according to any one of claims 15 to 17,
The tilt state adjusting mechanism can be driven by a predetermined power,
The computer program for determining the end of the operation by stopping the power. A computer program according to any one of claims 15 to 18, wherein
The tilt state adjusting mechanism,
A variable-length leg for supporting the projector;
An adjustment switch for extending and retracting the legs by the power,
The computer program for determining the end of operation by turning off the adjustment switch. The computer program according to any one of claims 15 to 19,
The tilt state adjusting mechanism is provided at a plurality of locations, and can individually operate a supporting mechanism for supporting the projector,
A computer program for determining that the operation has been completed when the operation on all of the plurality of support mechanisms has been completed. A computer program according to any one of claims 15 to 20, wherein
A computer program for detecting the tilt state based on an output value of an angle sensor or an acceleration sensor provided near a side facing a fulcrum when the projector is tilted.

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