JP4992247B2 - Projection-type image display device - Google Patents

Description

  The present invention relates to a projection-type image display device having an unauthorized use prevention function.

  In recent years, projector-type video display devices such as projectors are rapidly spreading in various situations, such as for presentations at conferences, lectures at educational sites, and home theater viewing at home. Although it is relatively easy to carry, it is a disaster and theft damage is also increasing.

To prevent theft and fraudulent use, manufacturers are equipped with password change setting invalidation and screen lock functions. And this kind of technique is disclosed in, for example, JP 2004-77967.

JP 2004-77967 A

  In the technique disclosed in Japanese Patent Application Laid-Open No. 2004-77967, the user is prompted to input a password when the apparatus is activated, and the operation is permitted only when the password matches a password set in advance by a legitimate user. Prevents unauthorized use of the device. However, even when a legitimate owner uses it, a password input procedure for confirming the owner is necessary, and the operation is very complicated.

  An object of the present invention is to provide a projection-type image display device having an unauthorized use prevention function that suppresses a decrease in operability.

  An example of the present invention records a set value of a specific function of a projection display apparatus in a memory at a first timing, and the projection display apparatus displays when the processor detects a change to the set value Limit the use of.

  It is possible to provide a projection-type image display device that can prevent unauthorized use while suppressing a decrease in operability.

  Hereinafter, the best mode of the present invention will be described with reference to the drawings. In each drawing described below, elements having common functions are denoted by the same reference numerals, and description of elements once described is omitted.

  In the form of the invention described below, a theft is estimated by detecting a change in the installation state and setting state of a projection type video display device (hereinafter, may be simply abbreviated as “device” unless there is doubt) Realize a system that prevents unauthorized use later. The device installation state and the setting state include various states in which a change in the state can be detected. For example, as shown in Table 1, the installation state includes (1) installation posture, (2) installation direction, (3) installation location, (4) input state to the input terminal, (5) fixed state, etc. The setting state includes, for example, (1) a projection lens focus / zoom setting state, (2) a projection image distortion correction value, and (3) a projection image inversion setting state. And according to each state, the object from which the state change is detected is different as shown in Table 1. Details thereof will be described later. Hereinafter, these states are collectively referred to as “use state” of the projection type image display apparatus.

  In this embodiment, a theft is estimated based on a change in the installation state of the device (here, the installation posture), and the user is authenticated (eg, determined by entering a password) only when there is a change. It is characterized by simplifying complicated operations (procedures), reducing the frequency of authentication check opportunities, and reducing the complexity of operations.

  FIG. 1 is a block diagram of a projection type image display apparatus showing a first embodiment. In FIG. 1, 101 is a projection type video display device, 111 is an input terminal to which a video signal (not shown) is input, and 110 is an input signal for performing predetermined signal processing on the video signal input from the input terminal 111. The processing unit 104 is an image processing unit that performs image processing such as decoding and scaling on the video signal output from the input signal processing unit 110 and on-screen display, and 112 is an enlarged image processed by the image processing unit 104. The projection optical unit 113 projects a projected image. Reference numeral 105 denotes an operation button composed of a plurality of buttons arranged on a housing of a device (not shown), and 106 denotes a projection type image display using an infrared remote control signal (hereinafter abbreviated as “IR remote signal”). A remote controller (hereinafter abbreviated as “remote control”) for remotely controlling the apparatus, 107 an IR light receiving unit for receiving an IR remote signal from the remote control 106, and 108 detecting an installation angle formed by the apparatus and gravity. An angle sensor as means for reading a change in the installation posture of the apparatus from a change in value, 109 is an I / O unit that controls input from the IR light receiving unit 107 and the angle sensor 108, and 102 is an arithmetic control of the entire projection display apparatus Central Processing Unit (hereinafter abbreviated as “CPU”), 103 is a program for controlling the CPU 102, and A memory for storing various data such as a device usage status and a password, and a video signal (not shown) input from the input terminal 111 are subjected to predetermined processing by an input signal processing unit 110 and an image processing unit 104, and a projection optical unit An optical image (image) corresponding to the video signal is projected onto the screen 113 by 112, for example. Operations such as on / off of the device, functions provided in the device, and settings are performed by the operation button 105 or the remote controller 106, and the CPU 102 operates the operated button (not shown) in the operation button 105 or the IR light receiving unit 107, I. Processing corresponding to each IR remote signal received via the / O unit 109 is performed.

For example, when the activation of an unauthorized use prevention system for preventing unauthorized use of the projection display apparatus is set in advance by operating the operation button 105 , the CPU 102 determines the angle when the apparatus is turned on and activated. The installation angle of the projection display apparatus detected by the sensor 108 is acquired through the I / O unit 109. Then, the obtained installation angle is compared with the installation angle registered in advance in the memory 103 by the authorized user to calculate the change amount of the installation posture. Based on the amount of change, the CPU 102 determines whether or not there is theft, and determines whether or not to authenticate the user. If the CPU 102 determines that the authentication is unnecessary, the CPU 102 permits the subsequent operation. If not, the CPU 102 authenticates the user, and the password registered in advance in the memory 103 by the authorized user is stored in the operation button 105, for example. If input is made by an operation, the operation of the apparatus is permitted. The processing of the CPU 102 described above will be described in detail later using a flowchart.

  Some angle sensors have one, two, or three angle detection axes. Any angle sensor 108 may be used. As the memory 103 for storing the detected installation angle data, for example, an EEPROM, a FLASHROM, or the like can be cited.

  Needless to say, when the CPU 102 has a function equivalent to that of the I / O unit 109, each device connected to the I / O unit may be directly connected to the CPU.

  Next, the processing operation of the CPU 102 related to the unauthorized use prevention system will be described with reference to the flowcharts of FIGS.

  FIG. 2 is a flowchart showing activation setting processing of the unauthorized use prevention system. After the power is turned on, when activation of the unauthorized use prevention system is instructed by the operation button 105 or the remote control 106 in FIG. 1, the CPU 102 sets the activation setting of the unauthorized use prevention system in step (hereinafter abbreviated as “S”) 201. The processing is started, and the use state of the apparatus at that time, that is, the installation angle α indicating the installation posture shown in FIG. 3 in this embodiment is detected by the angle sensor 108 and registered in the memory 103 via the I / O unit 109. (S202). Next, as shown in FIG. 3, a password registration request screen 301 is displayed using the image processing unit 104 to prompt registration of a password for user authentication. When the password is registered by the user using the operation button 105 or the remote controller 106, the CPU 102 registers the password in the memory 103 (S203). Here, the password indicates a sequence of numbers, a sequence of characters, or a specific figure displayed in order, or a specific button / remote control key or the like is pressed. Next, it is registered in the memory 103 that the projection type video display apparatus is being activated (S204), the unauthorized use prevention system activation setting process is terminated (S205), and then normal normal operation is started. To do.

  FIG. 4 is a flowchart showing an operation process of the unauthorized use prevention system that operates immediately after the power is turned on. In FIG. 4, when the projection display apparatus 101 is turned on, the CPU 102 starts the operation of the unauthorized use prevention system (S401). First, whether the activation of the unauthorized use prevention system is set (on) or the memory 103 is set. The state of the unauthorized use prevention system activation setting stored in the server is confirmed (S402). If activation of the unauthorized use prevention system is not set in S402, the process proceeds to S410, and the apparatus is operated normally as it is. If the activation of the unauthorized use prevention system is set in S402, the installation angle α indicating the use state, that is, the installation posture is detected by the angle sensor 108 (S403), and the detected installation angle (hereinafter referred to as “detection angle”). ) And the installation angle α registered in the memory 103 (S404). At this time, in consideration of the accuracy of the angle sensor 108, a detection error of the angle sensor, for example, a margin of about ± 2 degrees may be allowed for collation between the detected angle and the registered installation angle. If the detected angle and the registered installation angle are collated and determined to be coincident or within the error range, it is considered that there is no change in the use state (in this case, the installation posture), and there is no theft. The normal operation is started as it is, and the operation process of the unauthorized use prevention system is ended (S411). If the detected angle is different from the registered installation angle in S404, a theft is presumed. Therefore, normal operations other than the power-off operation are prohibited in S405, and the image processing unit 104 is used as shown in FIG. A password input request screen 501 is displayed to prompt the user to input a password (S406), and it is determined whether or not the password input in S407 matches the registered password. Needless to say, normal operations other than the power-off operation are prohibited until the password registered by the operation button 105 or the remote controller 106 is input. If the password input in S407 matches the registered password, the password input request screen 501 is deleted (S408), the normal operation prohibition is canceled (S409), the normal operation is started (S410), and the unauthorized use is made. The operation process of the prevention system is terminated (S411). At this time, if an incorrect password is input a predetermined number of times (for example, 5 times), even the input of the password is prohibited, and the password may be completely disabled.

  As described above, according to the present embodiment, by detecting a change in use state (in this embodiment, a change in installation posture), an unauthorized use due to theft is estimated, an authentication check is performed, and the change must be detected. Since it is determined that the unauthorized use is not made due to theft and the procedure of the authentication check is omitted, the complicated authentication check at the time of normal use can be eliminated. That is, it is possible to realize an unauthorized use prevention system for a projection display apparatus while simplifying the complicated operation of the authentication check and suppressing deterioration in operability.

  In addition, some projection-type image display devices are originally equipped with an angle sensor for the purpose of correcting projection image distortion (so-called trapezoidal distortion) depending on the installation angle. In this case, this is used as a use state detector. Therefore, it is not necessary to add a new angle sensor and the cost is not increased.

  When the angle sensor 108 includes two or three detection axes, the angle sensor 108 should be mounted so that a plane composed of two orthogonal axes among the detection axes is parallel to a plane composed of the gravity direction and the projection direction. Thus, it is possible not only to detect the installation angle, but also to distinguish between floor-standing installation and ceiling-mounted installation, and the installation posture can be further limited.

  For example, when the angle sensor 108 having two angle detection axes as shown in FIG. 6 is provided, the plane includes a detection axis 601 and a detection axis 602, a gravity direction 603, and a projection direction 604 of the projection display apparatus. By mounting so as to be parallel to the plane, it is possible to detect the installation angle using the detection shaft 601 and discriminate between floor installation and ceiling installation using the detection shaft 602.

The above-described floor-standing installation refers to a state where the apparatus is installed with the upper surface of the apparatus facing upward. The ceiling installation is a state in which the apparatus is installed upside down. For example, as shown in FIG. 7, the apparatus 101 is attached to the ceiling 702 using a fixture (ceiling installation bracket) 701 or the like. It is the installation method seen in the etc.
Further, in addition to the unauthorized use prevention system described in the present embodiment, for example, as shown in FIG. 8, it is normal if the installation state is illegally changed to an easily visible portion on the casing of the projection display apparatus 101. If a logo sticker 801 that warns that an unauthorized operation is prohibited is attached, it is possible to inform the surrounding people that the unauthorized use prevention system has been activated, and it is possible to suppress theft more effectively. Become.

  FIG. 9 is a block diagram of a projection display apparatus according to the second embodiment. In FIG. 9, elements having the same functions as those in FIG.

  In the first embodiment, the theft is estimated by changing the installation posture. However, in the second embodiment, as shown in FIG. 9, instead of the angle sensor 108, a geomagnetic sensor 901 is used to change the usage state. The installation direction (see Table 1), which is a form, is detected, and theft is estimated by a change in the installation direction.

  This embodiment is otherwise the same as the first embodiment, and the description thereof is omitted. Needless to say, the same effect as in the first embodiment can be obtained in the second embodiment.

  Next, a third embodiment will be described. FIG. 10 is a block diagram of a projection type image display apparatus showing a third embodiment.

  In the first embodiment, the theft is estimated by changing the installation posture. In the third embodiment, as shown in FIG. 10, instead of the angle sensor 108, the distance measurement sensor 1001 is used to project the projection distance. Or the distance with a wall surface is detected, the change of the installation place (refer Table 1) which is one form of a use condition is read from the change of the detected distance, and a theft is estimated.

  This embodiment is otherwise the same as the first embodiment, and the description thereof is omitted. Needless to say, the same effect as in the first embodiment can be obtained in the third embodiment.

  Next, a fourth embodiment will be described. FIG. 11 is a block diagram of a projection display apparatus according to the fourth embodiment.

  In the first embodiment, the theft is estimated by changing the installation posture. In the fourth embodiment, as shown in FIG. 11, the angle sensor 108 is not used and the CPU 102 uses the monitor camera 1101 as shown in FIG. The surrounding scenery is detected, the change in the installation location is read from the detected change in the scenery around the device, and theft is predicted.

  As an example of detecting a landscape around the apparatus, for example, as shown in FIG. 12, a monitor camera 1101 is provided beside the projection lens, and a landscape 1201 in the projection direction is detected and registered as a peripheral landscape, and a landscape other than the registered landscape. A method of prohibiting the normal operation of the apparatus when detecting is detected.

  This embodiment is otherwise the same as the first embodiment, and the description thereof is omitted. Needless to say, the same effect as in the first embodiment can be obtained in the fourth embodiment.

  In the first embodiment, the theft is estimated by changing the installation posture using the angle sensor. However, in the fifth embodiment, the angle sensor 108 is not used in FIG. In this embodiment, the CPU 102 detects a change in the signal input from the input terminal 111 by the input signal processing unit 110, reads the change in the input state to the input terminal from the detected signal change, and estimates theft. To do.

  As an example of detecting a change in an input signal, for example, a state where an XGA, 85 Hz signal is input to an RGB signal input terminal is registered, and an input of a signal other than the registered signal is detected. And a method for prohibiting normal operation of the system.

  Next, a sixth embodiment will be described. FIG. 13 is a block diagram of a projection type image display apparatus showing the sixth embodiment.

  In the first embodiment, the theft is estimated by changing the installation posture. In the sixth embodiment, as shown in FIG. 13, the angle sensor 108 is not used and the connector or plug 1301 to the input terminal 111 is used. Is detected, the change in the input state to the input terminal is read from the presence / absence of insertion of the connector or plug 1301, and theft is estimated.

  As an example of detecting the presence or absence of the insertion of a connector or plug into the input terminal, for example, the presence or absence of the insertion of an RCA plug is detected by using an RCA jack with a switch at the input terminal, and the state of insertion is registered and inserted. For example, a method of prohibiting normal operation of the apparatus when the absence is detected.

  Next, a seventh embodiment will be described. FIG. 14 is a block diagram of a projection type video display apparatus showing a seventh embodiment, and FIG. 15 is a diagram showing a fixed state of the projection type video display apparatus.

  As shown in FIG. 7, this embodiment can be suitably applied when the projection display apparatus 101 is fixed to, for example, a ceiling 702 using a fixing bracket (ceiling mount bracket) 701 or the like.

  In this embodiment, as shown in FIGS. 14 and 15, the change in the fixed state is read from the presence or absence of fixing to the fixing device (here, the ceiling) of the device detected using the fixing screw 1401 and the switch 1402, and theft is prevented. Infer.

  In FIG. 14, elements having the same functions as those in FIG. Needless to say, the same effect as in the first embodiment can be obtained in the seventh embodiment.

  In the first to seventh embodiments, theft prediction is performed by changing the installation state among the usage states shown in Table 1, that is, (1) installation posture, (2) installation direction, (3) installation location, and (4) input. This is performed by changing the input state to the terminal and (5) the fixed state, but in the eighth embodiment, it is performed by changing the setting state of the apparatus.

  FIG. 16 is a block diagram of a projection type image display apparatus showing an eighth embodiment. In FIG. 16, elements having the same functions as those in FIG.

  In this embodiment, as shown in FIG. 16, the position of the projection lens 1601 of the projection optical unit 112 is detected using a potentiometer 1602, and the change in the focus / zoom setting state is detected from the detected change in the position of the projection lens. Guess reading, theft and unauthorized use.

  Next, a ninth embodiment will be described. In the present embodiment, a projection image distortion (so-called trapezoidal distortion) correction value is used instead of the theft estimation based on the change in the zoom / focus setting state of the lens by the potentiometer of the eighth embodiment. The projected image is distorted depending on the installation position of the apparatus and the distance to the screen. In order to correct this distortion, a distortion correction process is usually performed on the image data to be projected. In this embodiment, parameters for distortion correction processing are recorded in a memory, and the recorded CPU 102 stores a projection video distortion (so-called trapezoidal distortion) correction value last set by the user of the apparatus recorded in the memory 103 and a preset value. A projection video distortion correction value registered by a legitimate user is compared, a change in the projection video distortion correction value is read, and theft and unauthorized use due to theft are estimated. The hardware configuration in this case is the one excluding the angle sensor 108 of FIG. However, as shown in FIG. 25, the non-volatile memory 103 includes a storage area for storing the correction value 1 registered by the regular user registered in the system activation setting process of FIG. 2 and the correction value changed in other normal processes. 2 is provided separately.

  In the case of the present embodiment, since the correction value 2 that is corrected during the activation of the apparatus is used for detection of unauthorized use, unauthorized use up to once may be permitted. For example, if there is no password fraud prevention system or if the password lock is illegally released, unauthorized use is possible. In the case of unauthorized use, it is often necessary to change the projected image distortion correction value because the installation location and the installation position are different. In that case, the changed value is stored in the nonvolatile memory 103 as the correction value 2. That is, when there is a request for changing the correction value, it is determined whether the system activation setting process in FIG. 2 or the normal process is being performed. Is stored, and correction data is stored in the correction value 2 when normal processing is in progress. At the next start-up, the stored correction value 2 and the correction value 1 by the regular user are compared, and it is determined that the use is illegal depending on whether or not they match.

  The verification of the correction value is not limited to when the apparatus is turned on, but may be configured to be performed at a predetermined timing. Or, when the power-off request of the device is triggered, the correction value 1 and the correction value 2 are different, and after the power is turned off on the condition that the regular password has not been input a predetermined number of times, the next device activation is prohibited. It is good. In that case, the nonvolatile memory 103 is configured to have a flag for prohibiting activation of the apparatus, and processing for setting this flag is performed when the power is turned off. When the system is in the unauthorized use prevention system activation state, the apparatus activation process is advanced after checking the apparatus activation prohibition flag when the apparatus is activated.

  In the case of the above processing, when the system activation of FIG. 2 is performed when the apparatus power is turned on, even if the setting change is performed by the authorized user, a password request is always made at the next apparatus activation in FIG. Therefore, it is desirable that the system activation in FIG. 2 be performed immediately before the power OFF request. Therefore, when there is a power-off request, a pop-up that suggests system activation may be displayed on the screen. Or it is good also as a structure which requires the input of a password in the case of a setting change.

  Further, in FIG. 25, the first correction value by the authorized user and the second correction value changed during the normal processing are stored in the memory 103, and the correction value change is detected by comparing the two. However, the correction value storage area may be one, and a flag indicating that there is a change may be stored in the memory 103. In that case, the CPU 102 checks the flag at a predetermined timing such as when the apparatus is activated or when the power is turned off, thereby detecting that there has been a change and restricting the use of the apparatus.

  Furthermore, in the first embodiment, when a theft is estimated from a change in the usage state of the apparatus, normal operations other than power-off are prohibited, but in this embodiment, the operation for changing the projected image correction value is prohibited. May be.

  In the tenth embodiment, the CPU 102 performs the projection video reversal setting (so-called mirror setting) state last set by the user of the apparatus recorded in the memory 103 and the projection video reversal registered in advance by a legitimate user. Compare the setting status, read the change in the projected video reversal setting, and guess theft and unauthorized use. Also in the case of the present embodiment, the setting state 1 registered by the authorized user by the processing of FIG. 2 and the setting state 2 performed in the normal state by the authorized user or the unauthorized user are registered in different storage areas of the nonvolatile memory 103, respectively. To do. Further, as in the ninth embodiment, at least one unauthorized use may be permitted. The projection video inversion setting state 2 set at that time is compared with the setting state 1, and unauthorized use is detected depending on whether the setting contents match. Note that the comparison timing is not limited to when the power is turned on, as in the ninth embodiment.

  In the first example, when a change in the usage state of the apparatus is read and a theft is estimated, normal operation other than power-off is prohibited, but in this example, the change operation of the projected video inversion setting is prohibited. Also good.

  The first to tenth embodiments have been described above, but (1) the installation posture, (2) the installation direction, (3) the installation location described as the apparatus installation state examples in the first to tenth embodiments, (4-1) Signal input to input terminal, (4-2) Presence or absence of plug or connector insertion to input terminal, (5) Presence or absence of fixing to fixing device of device, and 8th to 10th implementations The lens (1) focus / zoom adjustment state (2) projection image distortion correction value (3) projection image inversion setting state described as an example of the device setting state in the example may be arbitrarily combined. By arbitrarily combining these, it is possible to further improve the accuracy of estimation of theft and unauthorized use.

  Next, an eleventh embodiment will be described. By providing the remote control 106 with a function of sending an unauthorized use prevention system release signal, it is possible to authenticate the user who has been performed with the password in the first embodiment with the release signal of the remote control.

  As shown in FIG. 17, when the usage state detected at the time of starting the apparatus is different from the registered usage state, the CPU 102 displays a screen 1701 requesting that the release button on the remote controller described above be pressed. The normal operation other than the power-off operation is prohibited until the system release signal is received from the remote control. When the system release signal is received, the screen 1701 requesting the release button is deleted, and normal operation is enabled. By controlling the device and the remote control in different locations by a legitimate user and preventing the remote control from being stolen with the device, the release button on the remote control can have the same effect as a password. In the embodiment, the same effect as in the first embodiment can be obtained.

  In the first embodiment, the normal operation of the device is prohibited when the usage state detected at the time of starting the projection type video display device is different from the registered usage state. However, the present invention is not limited to this. is not. In this case, the purpose is not to operate normally, and the apparatus may be operated abnormally.

  For example, as shown in FIG. 18, a flip screen 1801 that is always flipped up and down is displayed, a scramble screen 1901 that is scrambled as shown in FIG. 19 is displayed, or a blank screen 2001 as shown in FIG. 20 is displayed. You may make it display.

  In addition, as shown in FIGS. 21 and 22, the projection type video display device may include an audio signal generation unit 2101, an amplifier 2102, and a built-in speaker 2103 to issue an alarm.

  Next, an eleventh embodiment will be described. In this embodiment, instead of the logo sticker 801 in FIG. 8 described at the end of the first embodiment, an LED 2301 is provided as shown in FIG. 23, and the LED 2301 is provided in the housing of the video display device 201 as shown in FIG. Install in the easy-to-see part above. When the unauthorized use prevention system is activated, the LED 2301 can be turned on or blinked to inform surrounding people that the unauthorized use prevention system is activated, and theft can be effectively suppressed. It becomes.

It is a block diagram of the projection type video display apparatus which shows a 1st example. It is a flowchart which shows the starting setting process of an unauthorized use prevention system. It is a figure which shows the Example of password registration. It is a flowchart which shows the operation | movement process of an unauthorized use prevention system. It is a figure which shows the Example of a password input. It is a figure which shows the example of mounting of an angle sensor. It is a figure which shows the ceiling-mounted installation state of a projection type video display apparatus. It is a figure which shows the warning example by a logo sticker. It is a block diagram of the projection type video display apparatus which shows a 2nd Example. It is a block diagram of the projection type video display apparatus which shows a 3rd Example. It is a block diagram of the projection type video display apparatus which shows a 4th Example. It is a figure which shows the 4th Example. It is a block diagram of the projection type video display apparatus which shows a 6th Example. It is a block diagram of the projection type video display apparatus which shows a 7th Example. It is a figure which shows the fixed state of a projection type video display apparatus. It is a block diagram of the projection type video display apparatus which shows an 8th Example. It is a figure which shows cancellation | release of the unauthorized use prevention system by the remote control which is a 10th Example. It is a figure which shows the up-down inversion processing screen of 12th Example. It is a figure which shows the scramble process screen of 12th Example. It is a figure which shows the blank screen of a 12th Example. It is a block diagram of the projection type video display apparatus which shows the Example which issues the warning of a 12th Example. It is a figure which issues the warning of a 12th Example. It is a block diagram of the projection type video display apparatus which shows a 13th Example. It is a figure which shows the example of warning by lighting of LED in a 13th Example. It is a figure which shows the correction value storage area of the non-volatile memory 103 in a 9th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Projection type video display apparatus, 102 ... CPU, 103 ... Memory, 104 ... Image processing part, 105 ... Operation button, 106 ... Remote control, 107 ... IR light-receiving part , 108 ... Angle sensor, 109 ... I / O chip, 110 ... Input signal processing section, 111 ... Input terminal, 112 ... Projection optical section, 301 ... Password registration request screen, 501... Password input request screen, 601, 602... Detection axis, 603... Gravity direction, 604 ... projection direction, 701. 801 ... Logo sticker, 901 ... Geomagnetic sensor, 1001 ... Distance sensor, 1101 ... Monitor camera, 1201 ... Scenery in the projection direction, 1301 ... Connector / plug, 1401 .. Fixing screw, 1402... Switch, 1601... Projection lens, 1602 .. potentiometer, 1701 .. remote control release button request screen, 1801 .. reverse screen, 1901 .. scramble screen, 2001 ... Blank screen, 2101 ... Audio signal generator, 2102 ... Amplifier, 2103 ... Speaker, 2301 ... LED

Claims (3)

A projection-type image display device equipped with an unauthorized use prevention system for preventing unauthorized use by entering a password,
During activation of the unauthorized use prevention system, a first storage area for storing a set value of a predetermined function of the projection type video display device by a regular user as a normal value, and during normal operation of the projection type video display device A non-volatile memory having a second storage area for storing a change value for the set value;
When the projection type video display device is turned on next time, it compares the regular value and the change value, and if they do not match, has a processor that restricts the use of the projection type video display device,
The preset value of the predetermined function is a projection type video display device which is a projection video distortion correction value or a value indicating a projection video inversion setting state. If the processor detects that a change has been made to the set value, it requests a password,
2. The projection-type image display device according to claim 1, wherein when the input password is valid, the use restriction is lifted. The memory is non-volatile;
2. The projection display apparatus according to claim 1, wherein the processor stores a change history for the set value in the memory, and detects a change for the set value based on the change history.

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