JP2003005278A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal projector that automatically carries out the projection display of a displayed picture in a normal direction or of a normal shape corresponding to the installation angle of a casing. SOLUTION: A video signal S1 outputted from a personal computer, a TV tuner, etc., is inputted, a video signal processing such as gamma correction, resolution compensation is carried out by a video signal processing circuit 1 according to the characteristics of a liquid crystal panel, and then the liquid crystal panel 4 is driven by a video signal S2 after processing. The light intensity modulation of a light beam from a light source is carried out using an optical system 5 consisting of the light source a mirror, an optical filter, a projection lens, etc., through the liquid crystal panel driven by the video signal, and an image display is carried out by projecting the light beam on a projection screen 6 by using a projection lens. The installation angle of the casing of the liquid crystal projector is detected by an angle detecting means 3 consisting of an acceleration sensor, etc. A display screen correction means 2 corrects the scanning direction and the drive shape of the liquid crystal panel corresponding to the detected installation angle, thereby the projection display of the screen in the normal direction or of the normal shape is carried out regardless of the installation angle of the casing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector capable of detecting an installation angle of a housing and automatically projecting and displaying an image having a correct orientation and shape.

[0002]

2. Description of the Related Art Conventionally, manual adjustment has been performed each time so that an image having a normal orientation and shape can be projected and displayed according to the installation angle of a housing. For example, when the installation angle of the housing differs by 180 degrees in the direction perpendicular to the optical axis, such as when the housing is installed on the floor or suspended from the ceiling, the scanning direction of the liquid crystal panel is switched between the up, down, left and right directions. Had to be set. In addition, when the projector is placed on the floor, the projection screen is usually above the liquid crystal projector, so projection is performed with an elevation angle. When the screen surface is stretched within the vertical plane, the display screen becomes an inverted trapezoid with a small bottom and a large top. . In order to make this a normal, almost square image, it is necessary to install it by pushing the hem of the projection screen into the back. But,
Since such an installation is difficult, it is usually used on an inverted trapezoidal display screen, and the viewer feels uncomfortable. Further, when the left-right direction of the installed case is tilted from the horizontal direction, it is necessary to change the lengths of the left and right legs of the case to make the display screen upright so as to make a complicated adjustment. In order to solve the above-mentioned problem, as disclosed in Japanese Patent Laid-Open No. 8-251522, it is considered that the posture is controlled by controlling the retractable leg based on the tilt detection signal from the tilt detector. Has been. However, in this technique, for example, when the legs are installed toward the ceiling, not only the control is reversed but also the projected image is reversed, so that these switching adjustments have to be performed manually.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a liquid crystal projector for automatically projecting and displaying a display screen having a normal orientation and shape corresponding to the installation angle of a housing. The purpose is to do.

[0004]

A video signal processing circuit for driving a liquid crystal panel by inputting a video signal and a liquid crystal panel driven by the video signal perform light intensity modulation and project the image on a projection screen to display a video. In a liquid crystal projector including a housing that houses an optical system, an angle detection unit that detects the installation angle of the housing and the orientation or shape of the screen on the liquid crystal panel is corrected according to the installation angle of the housing. A display screen correction means is provided for driving and displaying an image in a normal direction or shape on the projection screen so that an image in a normal direction or shape is projected and displayed regardless of the installation angle of the housing.

The angle detecting means is a vertical direction detecting section for detecting the vertical direction of the installed housing, and the display screen correcting means is the vertical direction of the liquid crystal panel depending on the vertical direction of the housing detected by the vertical direction detecting section. As a scanning direction switching unit that drives by switching the left and right scanning directions, the housing can display an image in a normal orientation corresponding to floor installation or ceiling installation.

The vertical direction detection unit is a uniaxial acceleration sensor installed with its detection axis aligned in the vertical direction of the housing.

The up-down direction detecting section is composed of a micro switch which operates with a weight.

The angle detecting means is an elevation angle detecting section for detecting the elevation angle or depression angle of the installed housing in the optical axis direction, and the display screen correction means corresponds to the elevation angle or depression angle of the housing detected by the elevation angle detecting means. A keystone correction unit that drives the liquid crystal panel by performing keystone correction so that the display screen on the projection screen becomes almost square.

The elevation angle detector is a biaxial acceleration sensor installed with its detection axes aligned in the optical axis direction and the vertical direction of the housing.

The angle detecting means is a horizontal tilt angle detecting section for detecting the horizontal tilt angle of the installed housing, and the display screen correcting means corresponds to the horizontal tilt angle of the housing detected by the horizontal tilt angle detecting section. Then, the tilt angle is corrected so that both sides of the display screen on the projection screen are substantially vertical, and the tilt angle correction unit drives the liquid crystal panel.

The elevation angle detection section is a biaxial acceleration sensor installed with its detection axes aligned in the vertical and horizontal directions of the housing.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the concept of an embodiment of a liquid crystal projector according to the present invention. The video signal S1 output from a personal computer or a TV tuner is input, the video signal processing circuit 1 performs video signal processing such as gamma correction and resolution correction according to the characteristics of the liquid crystal panel, and the processed video signal S2. LCD panel 4
To drive. An optical system 5 including a light source, a mirror, an optical filter, a projection lens, and the like modulates the light intensity from the light source through a liquid crystal panel driven by a video signal, and projects the light on a projection screen 6 by the projection lens to display an image. . Here, the installation angle of the housing of the liquid crystal projector is detected by the angle detection means 3 including an acceleration sensor, and the scanning direction and drive shape of the liquid crystal panel are corrected by the display screen correction means 2 in accordance with the detected installation angle. , A normal screen should be projected and displayed regardless of the installation angle of the housing.

FIG. 2 is a block diagram of the essential parts of one embodiment of the liquid crystal projector according to the present invention. In addition, FIG.
(A) Side view of a floor-standing liquid crystal projector showing one embodiment of a liquid crystal projector according to the present invention, (B) Scanning direction of a liquid crystal panel of the floor-standing liquid crystal projector, (C) Side view of a ceiling-mounted liquid crystal projector, (D) 6 is a conceptual diagram showing a scanning direction of a liquid crystal panel of a ceiling-mounted liquid crystal projector. As the angle detecting means 3, the vertical direction detecting unit 21 for detecting the vertical direction of the housings of the installed liquid crystal projectors 31a and 31b is provided, and the installed liquid crystal projector is the floor-standing liquid crystal projector 31a or the ceiling-mounted liquid crystal projector. It is determined whether it is 31b. As the display screen correction means 2, a scanning direction switching unit 22 that switches and drives the up, down, left, and right scanning directions of the liquid crystal panel is provided. Scanning direction switching unit 22
Then, in the case of the floor-standing liquid crystal projector 31a, in consideration of the fact that the direction of the image is reversed by the projection lens in the scanning direction of the liquid crystal panel 4, as shown in FIG. And the display screen 32a on the liquid crystal panel is made an inverted image. Similarly, in the case of the ceiling-mounted liquid crystal projector 31b, the scanning direction of the liquid crystal panel 4 is set as shown in FIG.
As shown in (D), the start of the frame of the video signal is made to correspond to the upper right, and the display screen 32b on the liquid crystal panel is made an erect image. This allows the LCD projector to be installed on the floor without switching the drive circuit manually regardless of whether it is suspended from the ceiling.
A normal display screen that is automatically erected on the projection screen will be obtained. The scanning direction switching unit can be realized by reversing the shifting direction of the video signal in the X direction and the scanning direction of the scanning signal in the Y direction according to the conventional technique.
Alternatively, it can be realized by reading the video signals once stored in the frame memory in reverse order.

The vertical direction detector 21 can be composed of a uniaxial acceleration sensor installed with its detection axis aligned with the vertical direction of the housing. The acceleration sensor can also detect the acceleration of gravity, that is, the weighting direction, so by installing this with the detection axis aligned in the vertical direction of the housing,
Whether the liquid crystal projector is placed on the floor or suspended from the ceiling can be determined based on whether the weight detected is positive or negative.

Alternatively, the above-mentioned up-and-down direction detecting section 21 may be composed of a micro switch operated by a weight. FIG. 4 is a side view showing the concept of a microswitch that operates with a weight, where (A) is upright and (B) is inverted. By urging the movable rod 42 of the microswitch main body 41 with the lever 43 to move the movable rod 42 up and down, the switch in the microswitch main body 41 is turned on and off. At the tip of the lever 43, a weight 44 is attached which pushes down the movable rod to turn on the switch when the micro switch body 41 is placed upright. This micro switch is installed on, for example, the bottom surface of the housing of the liquid crystal projector. This allows
When the liquid crystal projector is placed on the floor, the weight 44 pushes down the movable rod to turn on the micro switch,
When the projector is suspended from the ceiling, it is inverted and the lever 43 is lowered to turn off the micro switch. By turning on / off the micro switch, it is possible to determine whether the liquid crystal projector is installed on the floor or suspended from the ceiling. In addition, the micro switch,
Stopper 45 that limits the movement of lever 43 when inverted
To provide.

FIG. 5 is a principal block diagram showing another embodiment of the liquid crystal projector according to the present invention. See also FIG.
FIG. 3 is a schematic diagram of (A) a display screen on a projection screen and (B) a display screen on a liquid crystal panel showing another embodiment of the liquid crystal projector according to the present invention (however, the figure shows the display on the projection screen. The screen is not considered to be an inverted image). Generally, the projection screen 6 is installed in a vertical plane, and the floor-oriented liquid crystal projector 31a projects the projection screen 6 upward. Therefore, the display screen 66 on the projection screen 6 has an inverted trapezoidal shape with a small lower part and a large upper part. Therefore, as the angle detection unit 3, an elevation angle detection unit 51 that detects the elevation angle or the depression angle in the optical axis direction of the installed housing is provided. Further, as the display screen correction means 2 described above, a trapezoidal correction unit 52 that performs trapezoidal correction of the display screen 64a on the liquid crystal panel 4 is provided. Then, the display screen 64a on the liquid crystal panel 4 has a trapezoidal shape so that the display screen 66 on the projection screen 6 becomes substantially rectangular corresponding to the elevation angle of the housing detected by the elevation angle detection unit 51 (however, the projection screen 6
Considering that the upper display screen 66 becomes an inverted image due to the projection lens, it becomes an inverted trapezoid). The trapezoid correction unit 52 uses a line memory or a frame memory to display the liquid crystal panel 4
In order that the upper display screen 64a becomes a trapezoid, the number of display pixels in the upper part is decreased and gradually increased downward, and black screens 64b are inserted on both sides thereof. Further, the elevation angle detection unit 51 is configured by a biaxial acceleration sensor installed with the detection axes aligned with the optical axis direction of the liquid crystal projector and the vertical direction.
Thereby, the elevation angle or depression angle in the optical axis direction can be detected. When projecting from a liquid crystal projector at an angle of depression,
Reverse the keystone correction on the LCD panel.

FIG. 7 is a block diagram of a main part of still another embodiment of the liquid crystal projector according to the present invention. See also FIG.
FIG. 3 is a schematic diagram of (A) a display screen on a projection screen and (B) a display screen on a liquid crystal panel showing another embodiment of the liquid crystal projector according to the present invention (however, the figure shows the display on the projection screen. The screen is not considered to be an inverted image). As the angle detection means 3, a horizontal tilt angle detection unit 71 that detects the horizontal tilt angle of the housing of the installed liquid crystal projector is installed. Further, as the above-mentioned display screen correction means 2, the display screen 8 on the projection screen 6 corresponding to the horizontal tilt angle of the housing detected by the horizontal tilt angle detection unit 71.
The liquid crystal panel 4 is corrected by correcting the tilt angle so that
The tilt angle correction unit 72 for driving. The tilt angle correction unit 72 can be realized by performing address conversion and reading the video signal once stored in the frame memory so as to obtain the tilt-corrected display screen 84a. A black screen 84b is inserted around the display screen 84a. Further, the horizontal tilt angle detection unit 71 can be configured by a conventional technique including a biaxial acceleration sensor in which detection axes are aligned in the vertical direction and the horizontal direction of the housing.

[0018]

As described above, the video signal processing circuit for inputting the video signal to drive the liquid crystal panel and the light intensity modulation by the liquid crystal panel driven by the video signal are projected on the projection screen. In a liquid crystal projector including a housing that houses an optical system for displaying images, an angle detection unit that detects the installation angle of the housing and the orientation or shape of the screen on the liquid crystal panel corresponding to the installation angle of the housing. A liquid crystal projector installed by providing a display screen correction means for performing a normal image display on the projection screen by correcting and driving so that a normal image is projected and displayed regardless of the installation angle of the housing. It becomes possible to automatically project and display a display screen in a normal direction or shape in accordance with the angle, without any manual adjustment.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the concept of an embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is a block diagram of a main part of an embodiment of a liquid crystal projector according to the present invention.

FIG. 3A is a side view of a floor-standing liquid crystal projector showing an embodiment of a liquid crystal projector according to the present invention; FIG.
The scanning direction of the LCD panel of the floor-standing LCD projector,
(C) is a side view of the ceiling-mounted liquid crystal projector, and (D) is a conceptual diagram showing a scanning direction of a liquid crystal panel of the ceiling-mounted liquid crystal projector.

FIG. 4 is a side view showing the concept of a micro switch that operates with a weight, where (A) is upright and (B) is inverted.

FIG. 5 is a principal block diagram showing another embodiment of the liquid crystal projector according to the present invention.

6A and 6B are schematic diagrams of (A) a display screen on a projection screen and (B) a display screen on a liquid crystal panel showing another embodiment of the liquid crystal projector according to the present invention.

FIG. 7 is a block diagram of a main part of still another embodiment of the liquid crystal projector according to the present invention.

FIG. 8 is a schematic diagram of (A) a display screen on a projection screen and (B) a display screen on a liquid crystal panel, showing another embodiment of the liquid crystal projector according to the present invention.

[Explanation of symbols]

1 Video signal processing circuit 2 Display screen correction means 3 Angle detection means 4 LCD panel 5 Optical system 6 Projection screen 21 Vertical direction detector 22 Scanning direction switching unit 31a Floor-standing liquid crystal projector 31b Ceiling-mounted LCD projector 32a, 32b display screen 41 Micro switch body 42 movable rod 43 lever 44 weight 45 stopper 51 Elevation detector 52 Keystone correction unit 64a display screen 64b black screen 66 Display screen 71 Horizontal tilt angle detector 72 Tilt correction unit 84a display screen 84b black screen 86 display screen S1 and S2 video signals

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 680 G09G 3/20 680C 3/36 3/36 H04N 5/74 H04N 5/74 D

Claims (8)

[Claims] 1. A video signal processing circuit for driving a liquid crystal panel by inputting a video signal, and an optical system for performing light intensity modulation by the liquid crystal panel driven by the video signal and projecting it on a projection screen for image display. In a liquid crystal projector including a housing that is housed, projection is performed by driving by correcting the orientation or shape of the screen on the liquid crystal panel in accordance with the angle detection means that detects the installation angle of the housing and the installation angle of the housing. A liquid crystal projector characterized in that display screen correction means for displaying an image in a normal orientation or shape is provided on a screen so that a normal image is projected and displayed regardless of the installation angle of the housing. 2. The angle detecting means is a vertical direction detecting section for detecting the vertical direction of the installed housing, and the display screen correcting means is a liquid crystal panel according to the vertical direction of the housing detected by the vertical direction detecting section. 2. The scanning direction switching unit for switching and driving the upper, lower, left and right scanning directions of the housing enables the case to display an image in a normal orientation corresponding to floor installation or ceiling installation. The liquid crystal projector according to item 1. 3. The liquid crystal projector according to claim 2, wherein the vertical direction detection unit is a uniaxial acceleration sensor having a detection axis aligned in the vertical direction of the housing. 4. The liquid crystal projector according to claim 2, wherein the up-down direction detection unit includes a micro switch that operates with a weight. 5. The angle detecting means is an elevation angle detecting section for detecting an elevation angle or a depression angle in an optical axis direction of an installed casing, and the display screen correcting means corresponds to the elevation angle or the depression angle of the casing detected by the elevation angle detecting means. 2. The liquid crystal projector according to claim 1, further comprising a trapezoidal correction unit that drives the liquid crystal panel by performing trapezoidal correction so that the display screen on the projection screen becomes substantially rectangular. 6. The liquid crystal projector according to claim 5, wherein the elevation angle detection unit is a biaxial acceleration sensor having detection axes aligned in the optical axis direction and the vertical direction of the housing. 7. The angle detecting means is a horizontal tilt angle detecting section for detecting a horizontal tilt angle of the installed housing, and the display screen correcting means is a horizontal tilt angle of the housing detected by the horizontal tilt angle detecting section. 2. A tilt angle correction unit for driving a liquid crystal panel by performing tilt correction so that both sides of a display screen on a projection screen are substantially vertical corresponding to the above.
The liquid crystal projector according to item 1. 8. The liquid crystal projector according to claim 7, wherein the elevation angle detection unit is a biaxial acceleration sensor installed with its detection axes aligned in the vertical and horizontal directions of the housing.