Abstract: A central position detection section has a detection width in which the central position has a median value along one axial direction. When the direction from a position, which is located at the time at which returning is started toward the central position is defined as a go direction, the control section commands that a drive mechanism should sequentially perform following operations: a first operation of driving a projection lens assembly in the go direction; a second operation of allowing the projection lens assembly to travel in a return direction at least by the detection width; and a third operation of allowing the projection lens assembly to travel in the detection width in the go direction by ½ of the detection width traveled in the go direction.

Abstract: A projection image display apparatus including a detachably attachable light source unit includes: a storage means provided to the light source unit and having previously stored therein information that the light source unit is a genuine product; a determination means making a comparison with the information in the storage means to determine whether the light source unit is the genuine product; and a light source control means controlling an output of the light source unit in accordance with a result from the determination means.

Abstract: A central position detection section has a detection width in which the central position has a median value along one axial direction. When the direction from a position, which is located at the time at which returning is started toward the central position is defined as a go direction, the control section commands that a drive mechanism should sequentially perform following operations: a first operation of driving a the projection lens assembly in the go direction; a second operation of allowing the projection lens assembly to travel in a return direction at least by the detection width; and a third operation of allowing the projection lens assembly to travel in the detection width in the go direction by ½ of the detection width traveled in the go direction.

Abstract: A image distortion correction unit which corrects a distortion of a projected image includes: a switching unit which operates in response to an operation signal from a Keystone remote controller button to switch correction by a trapezoidal distortion correction process and correction by a corner distortion correction process back and forth; a determination unit which determines whether any one of the correction by the trapezoidal distortion correction process and the correction by the corner distortion correction process has been performed; and a prohibition unit which prohibits switching the trapezoidal distortion correction process and the corner distortion correction process back and forth if the determination unit determines that any one of the correction by the trapezoidal distortion correction process and the correction by the corner distortion correction process has been performed and the operation signal is also received from the Keystone remote controller button.

Abstract: A video projector for displaying a picture based on a video signal. The video projector includes a first LCD panel for red light, a second LCD panel for green light, and a third LCD panel for blue light. A light source emits light toward the first to third LCD panels. A modulated light computer determines a correction coefficient for reducing the amount of light emitted from the light source toward the first to third LCD panels when temperature load of at least one of the first to third LCD panels increases. An emitted light amount control unit corrects the video signal with the correction coefficient and controls the amount of light emitted from the light source toward the first to third LCD panels.

Abstract: A projector comprises: a cooling fan for sucking ambient air through a filter; switching means for switching the operational mode of the cooling fan between a lowland mode and a highland mode; and control means adapted to obtain current fan voltage to determine the normal rpm value for that current fan voltage in reference to a highland voltage-rpm characteristic when the switching means is in the highland mode, obtain current fan rpm, and enables alarming means to issue a filter clogging alarm in the event that the current fan rpm is larger than the normal rpm value plus a predetermined value. Thus, filter clogging can be detected with precision in highlands.

Abstract: A lens shift mechanism includes a projection lens drive unit, a vertical-horizontal limit sensor which detects that a projection lens apparatus reaches a limit in a shift range in vertical and horizontal directions, and a vertically-horizontally central sensor which detects that the projection lens apparatus reaches a central position in the shift range. The vertically-horizontally central sensor has a detection width having a central value at the central position. When a microcomputer automatically returns the projection lens apparatus to the central position within the shift range after a shift operation, the microcomputer shifts the projection lens apparatus in a forward direction directed from a position at a time point when automatic return is started toward the central position, and thereafter shifts the projection lens apparatus again in a backward direction by substantially half the detection width of the vertically-horizontally central sensor.

Abstract: A projector includes: an image signal processing circuit which receives and converts a first image signal to generate a second image signal representing an image to be projected; an image distortion correction unit which corrects the second image signal in response to a correction point on a projected image being changed by an operation done by a user; and an OSD circuit which operates, in response to an image distortion correction process being selected in response to an operation done by the user, to superpose a correction pattern used to allow the user to designate the correction point on the projected image, and thus display the correction pattern and the projected image on a single screen. The OSD circuit includes a switching control unit which switches a color used to display the correction pattern when the image distortion correction process is performed.

Abstract: A image distortion correction unit which corrects a distortion of a projected image includes: a switching unit which operates in response to an operation signal from a Keystone remote controller button to switch correction by a trapezoidal distortion correction process and correction by a corner distortion correction process back and forth; a determination unit which determines whether any one of the correction by the trapezoidal distortion correction process and the correction by the corner distortion correction process has been performed; and a prohibition unit which prohibits switching the trapezoidal distortion correction process and the corner distortion correction process back and forth if the determination unit determines that any one of the correction by the trapezoidal distortion correction process and the correction by the corner distortion correction process has been performed and the operation signal is also received from the Keystone remote controller button.

Abstract: A video projector for displaying a picture based on a video signal. The video projector includes a first LCD panel for red light, a second LCD panel for green light, and a third LCD panel for blue light. A light source emits light toward the first to third LCD panels. A modulated light computer determines a correction coefficient for reducing the amount of light emitted from the light source toward the first to third LCD panels when temperature load of at least one of the first to third LCD panels increases. An emitted light amount control unit corrects the video signal with the correction coefficient and controls the amount of light emitted from the light source toward the first to third LCD panels.

Abstract: A projection image display apparatus includes: a light source unit configured to be detachably attachable to a main body of the apparatus; a storage unit provided to the light source unit for previously storing therein information that the light source unit is a genuine product; a determination unit verifying the information stored in the storage unit to make a decision on whether the light source unit is the genuine product; and a light source control unit operative in accordance with the decision made by the determination unit to control an output of the light source unit. The determination unit transmits a signal to the storage unit. The storage unit receives and encrypts the signal in accordance with the information and transmits the encrypted signal to the determination unit. The determination unit receives and reconstructs the encrypted signal to verify the information.

Abstract: An electronic device with an opening/closing door of the present invention includes a device body in which an opening is defined, a shutter system capable of covering and exposing the opening, and a loosely fixing mechanism. The shutter system includes a door capable of moving back and forth between a closed position for covering the opening and an open position for exposing the opening, an arm swingably supported by the device body and having a front end engaging with the door, a motor for opening and closing the door by driving the arm, and a controller for controlling the operation of the motor. The controller is capable of switching the function of the motor between an electric motor and an electric generator. The loosely fixing mechanism is linked to the arm of the shutter system, and loosely fixes the arm when the door is placed at the open position, while loosely fixing the arm when the door is placed at the closed position.

Abstract: A projection image display apparatus including a detachably attachable light source unit includes: a storage means provided to the light source unit and having previously stored therein information that the light source unit is a genuine product; a determination means making a comparison with the information in the storage means to determine whether the light source unit is the genuine product; and a light source control means controlling an output of the light source unit in accordance with a result from the determination means.

Abstract: A projection-type picture display device for displaying an entire OSD image in a state superimposed on a picture without any part of the OSD image overhanging from the picture. An aspect ratio changing unit adjusts the size of the picture by changing an aspect ratio of the picture. An image generation unit generates the OSD image including characters superimposed on the picture. An image synthesizing unit synthesizes the OSD image with the picture of which the aspect ratio has been changed to superimpose the OSD image on the picture. A trapezoidal distortion correction unit performs trapezoidal distortion correction on the picture that has been synthesized with the OSD image in the image synthesizing unit. The image generation unit adjusts the size of the characters in the OSD image in accordance with the size of the picture of which the aspect ratio has been changed.

Abstract: A projector comprises: a cooling fan for sucking ambient air through a filter; switching means for switching the operational mode of the cooling fan between a lowland mode and a highland mode; and control means adapted to obtain current fan voltage to determine the normal rpm value for that current fan voltage in reference to a highland voltage-rpm characteristic when the switching means is in the highland mode, obtain current fan rpm, and enables alarming means to issue a filter clogging alarm in the event that the current fan rpm is larger than the normal rpm value plus a predetermined value. Thus, filter clogging can be detected with precision in highlands.