JP2007248711A - Projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type image display device capable of retaining the on or off state of a lamp even if a main control means is subjected to hardware-reset. <P>SOLUTION: The projection type image display unit includes: an EEPROM 9 for storing the on or off state of the lamp 4 before the hardware reset of a main control microcomputer 1; and a pull-up resistor 6 holding output ports A and B in predetermined conditions during the hardware reset of the main control microcomputer 1. Based on the on or off state of the lamp, stored in the EEPROM 9, the main control microcomputer 1 controls the output ports A and B when restoring from the hardware reset. On the other hand, a lamp ballast control microcomputer 2 exerts control such that the lamp 4 is turned on if the lamp 4 is in a predetermined condition for not shorter than a predetermined time required for the output port A of the main control microcomputer 1 to come to an output port controllable state from the hardware reset of the main control microcomputer 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection display apparatus such as a liquid crystal projector, and more particularly to its reset function.

  As a means of resetting the microcomputer or CPU when the microcomputer or CPU goes out of control in a device or system using a microcomputer (CPU) or CPU (Central Processing Unit) as well as a projection display such as a liquid crystal projector. Initializes at the software (program) level and maintains the hardware level status (eg, output port status), and the software reset that can be held, and initializes at the hardware level, that is, performs all initialization. Thus, there is a hardware reset that returns to a state where the power is turned off and then on again (for example, see Patent Document 1).

Even in the projector, there is a means for resetting the microcomputer when the program of the main control microcomputer runs away. In this case, it was a software reset and the lamp control could be continued. However, it was only a software reset, and when the microcomputer was out of control due to noise or the like, there was no means to reset it and return it to normal. In addition, if hardware reset is performed, continuous lamp control cannot be performed and the lamp is turned off.
JP 2005-85258 A (G08B 13/12)

  As described above, when the main control microcomputer of the projector goes out of control, it is necessary to maintain the lamp lighting state when the lamp is lit. Therefore, the hardware reset cannot be performed and the software reset must be performed. Therefore, there has been no means for returning the lamp to the normal state when the lamp has runaway due to hardware.

  Accordingly, the present invention has been made to solve such a problem, and a projection image display apparatus capable of maintaining the lighting / extinguishing state of the lamp even when a hardware reset is applied to the main control means. It is intended to provide.

  In order to achieve the above-described object, the invention according to claim 1 of the present application controls main control means for controlling the entire apparatus and power supply from a booster circuit to a lamp serving as a light source for projecting an image. Lamp driving means for driving the lamp, and lamp driving control means for controlling lighting / extinguishing of the lamp by controlling the lamp driving means, wherein the lamp driving control means and the booster circuit are the main driving circuit. Controlled by the state of the output port of the control means, wherein the main control means is a projection-type video display device in which the output port is set to a predetermined state and the lamp is turned on. A non-volatile memory for storing the lighting / extinguishing state of the lamp before the execution of the wear reset, and the state of the output port when the hardware reset of the main control means is Holding means for holding in the predetermined state, and the main control means controls the output port based on the lamp lighting / extinguishing state stored in the nonvolatile memory when returning from a hardware reset, The lamp driving control means controls the lamp to be lit when the output port of the main control means is in the predetermined state for a predetermined time longer than a time when the output port can be controlled from a hardware reset of the main control means. It is characterized by doing.

  The invention according to claim 2 is characterized in that the holding means comprises a pull-up resistor interposed between the output port and a power source of a predetermined voltage to pull up the output port.

  The invention according to claim 3 is characterized in that, as the predetermined time, a time required for the booster circuit to completely drive after the output port of the main control means is set to the predetermined state is set. Is.

  According to the first aspect of the present invention, since the output port is held in a predetermined state by the holding means even when a hardware reset is performed during lamp lighting, the lamp lighting state can be held. When a hardware reset is performed when the lamp is turned off, the output port is initially set to a predetermined state by the holding means. However, the main control means does not execute the hardware reset stored in the nonvolatile memory when returning from the hardware reset. While the output port is controlled based on the lamp on / off state (in this case, the lamp off state), the lamp driving control means is the time during which the output port of the main control means can control the output port from the hardware reset of the main control means. If the lamp is not in the predetermined state for the predetermined time or longer, the lamp is not controlled to be turned on, so that the lamp extinguished state is maintained. Therefore, even if a hardware reset is applied to the main control means, the lighting / extinguishing state of the lamp can be maintained.

  According to the second aspect of the present invention, since the holding means is made of a pull-up resistor, the above-described effects can be realized with a simple configuration.

  According to the invention of claim 3, since the time required for the booster circuit to completely drive after the output port of the main control means is set to the predetermined state is set as the predetermined time, the hardware reset Sometimes, the lamp can be reliably turned on / off.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a main configuration of a liquid crystal projector according to an embodiment of the projection display apparatus of the present invention. Here, only the configuration according to the embodiment of the present invention is shown.

  In FIG. 1, a main control microcomputer (main control means) 1 of a liquid crystal projector, a lamp ballast control microcomputer (lamp drive control means) 2, a lamp ballast (lamp drive means) 3, and an image for projecting an image. A lamp 4 as a light source and a booster circuit 5 are shown.

  The main control microcomputer 1 controls the entire liquid crystal projector. Here, the main control microcomputer 1 communicates with the lamp ballast control microcomputer 2 and the booster circuit 5. The lamp ballast control microcomputer 2 controls the lamp ballast 3 to turn on or off the lamp 4 via the lamp ballast 3.

  The communication lines between the main control microcomputer 1 and the lamp ballast control microcomputer 2 are connected to the output port A of the IO (Input Output) port of the main control microcomputer 1 and the input port of the IO port of the lamp ballast control microcomputer 2 as circuits. They are connected and connected to a 5V power source via a pull-up resistor 6. Further, an output port B of another system of the IO port of the main control microcomputer 1 is connected to the booster circuit 5 and is also connected to a 5V power source through the pull-up resistor 7.

  When the lamp 4 is turned on, the booster circuit 5 is driven by setting the output port B of the main control microcomputer 1 to the HIGH level. When the booster circuit 5 is driven, power is supplied to the lamp ballast control microcomputer 2 and the lamp ballast 3. When the output port A of the main control microcomputer 1 is set to the HIGH level, the lamp 4 can be turned on.

  When the lamp 4 is turned off, the lamp 4 can be turned off by setting the output port A of the main control microcomputer 1 to the LOW level. Thereafter, the booster circuit 5 is stopped by setting the output port B of the main control microcomputer 1 to the LOW level. When the booster circuit 5 is stopped, the supply of power to the lamp ballast control microcomputer 2 and the lamp ballast 3 is stopped.

  If the main control microcomputer 1 runs out of hardware due to noise, etc. when the lamp is lit, and the hardware reset is applied by the internal watchdog timer, the output port A of the main control microcomputer 1 is in a high impedance state. Since it is pulled up, it becomes HIGH level. Similarly, the output port B of the main control microcomputer 1 becomes HIGH level. When the inside of the main control microcomputer 1 is stabilized, the program is executed and the IO port can be controlled for the first time.

  The main control microcomputer 1 has an EEPROM (Electrically Erasable Programmable Read Only Memory) 9 as a nonvolatile memory for storing the lighting / extinguishing state of the lamp 4 and stores the lighting / extinguishing state of the lamp 4.

  When the hardware reset is applied to the main control microcomputer 1 when the lamp 4 is in the lighting state, the output port A and the output port B become HIGH level, and the lighting state of the lamp 4 is maintained. When the main control microcomputer 1 is stabilized, the program is executed. The EEPROM 9 stores information on the lighting / extinguishing state (in this case, the lighting state) of the lamp 4 immediately before the hardware reset is performed. Based on this information, the output port A and the output port B are controlled, and the HIGH level ( Leave it on.

  On the other hand, when the hardware reset is applied to the main control microcomputer 1 when the lamp 4 is turned off, the output port A and the output port B are at a high level and are about to be turned on. It takes a certain time (about 600 ms) to drive completely. On the other hand, since the time (about 3 ms) in which the inside of the main control microcomputer 1 is stabilized is earlier, the main control microcomputer 1 executes the program and the lamp immediately before the hardware reset stored in the EEPROM 9 is applied. Based on the information of the ON / OFF state of (in this case, the OFF state), the output port A and the output port B are controlled and set to the LOW level (OFF state).

  A specific description will be given based on the flowchart shown in FIG. 2A shows a flowchart of the main control microcomputer 1, and FIG. 2B shows a flowchart of the lamp ballast control microcomputer 2.

  As shown in FIG. 2A, the main control microcomputer 1 checks whether or not the output ports A and B are at the HIGH level, and if they are HIGH, stores information indicating that the lamp is lit in the EEPROM 9 ( Y in step S101 → step S102). If it is not HIGH level, that is, if it is LOW level, information indicating that the lamp is extinguished is stored in the EEPROM 9 (N in Step S101 → Step S103).

  Then, a hardware reset is executed (step S104). When the hardware reset is executed, the output ports A and B are high impedance, that is, the output ports A and B are set to the HIGH level by the pull-up resistors 6 and 7 (step S105).

  When the operation of the main control microcomputer 1 becomes stable and becomes controllable (step S106), information indicating the lamp on / off state is acquired from the EEPROM 9 (step S107). Based on this information, it is checked whether or not the lamp is lit. If the lamp is lit, the output ports A and B are set to the HIGH level (Y in step S108 → step S109), and the lamp is not lit, that is, not lit. For example, the output ports A and B are set to the LOW level (N in step S108 → step S110).

  On the other hand, as shown in FIG. 2B, the lamp ballast control microcomputer 2 checks whether the output port A of the main control microcomputer 1 is at a HIGH level for 600 ms or more, and if it is at a HIGH level for 600 ms or more. The lamp 4 is turned on (Y in step S201 → step S202), and the lamp 4 is turned off if it is not HIGH level for 600 ms or longer (N in step S201 → step S203).

  Here, the time required for the processing (steps S105 to S110) within the broken line in FIG. 2A, that is, the time until the main control microcomputer 1 becomes capable of controlling the output port after the hardware reset is the main control microcomputer 1 After the output ports A and B are set to the HIGH level, the processing is completed in several tens of milliseconds to several hundreds of milliseconds, which is surely smaller than the above 600 ms, which is the time required for the booster circuit 5 to be completely driven. Therefore, the lamp lighting state is maintained when the hardware reset is applied when the lamp is lit, and the lamp extinguishing state is also maintained when the hardware reset is applied when the lamp is turned off.

  Therefore, even when a hardware reset is applied while the main control microcomputer 1 of the liquid crystal projector has run away due to noise or the like, the main control microcomputer 1 is brought into a normal state while the lamp 4 is kept on / off. Can be returned.

  Further, as the determination time of step S201 in FIG. 2B, 600 ms, which is a time required for the booster circuit 5 to be completely driven after the output ports A and B of the main control microcomputer 1 are set to the HIGH level, is set to 600 ms. Since the setting is made, the lamp 4 can be reliably turned on / off even when the hardware is reset.

  Further, since the output ports A and B of the main control microcomputer 1 are configured to be at a HIGH level using the pull-up resistors 6 and 7 at the time of hardware reset, the above-described effects can be realized with a simple configuration. it can.

  In the above embodiment, a liquid crystal projector using a liquid crystal panel is shown as the projection display apparatus. However, the present invention can also be applied to a projection display apparatus having another image light generation system. That is, the present invention can be applied not only to the front projection type but also to the rear projection type image display device. The present invention can also be applied to a projector of a DLP (Digital Light Processing; registered trademark of Texas Instruments (TI)) system.

1 is a block diagram showing a main configuration of a liquid crystal projector according to an embodiment of a projection display apparatus of the present invention. The flowchart which shows the operation | movement of the microcomputer for the main control and the microcomputer for lamp ballast control.

Explanation of symbols

1 Microcontroller for main control 2 Microcomputer for lamp ballast control 3 Lamp ballast 4 Lamp 5 Booster circuit 6, 7 Pull-up resistor 9 EEPROM

Claims (3)

Main control means for controlling the entire apparatus, lamp driving means for controlling power supply from a booster circuit to a lamp serving as a light source for projecting an image to drive the lamp, and controlling the lamp driving means to Lamp driving control means for controlling lighting / extinguishing of the lamp, the lamp driving control means and the booster circuit are controlled by the state of the output port of the main control means, and the main control means sets the output port to a predetermined value. A projection-type image display device that is set to a state of
A non-volatile memory for storing the lighting / extinguishing state of the lamp before execution of hardware reset of the main control means, and the state of the output port at the time of hardware reset execution of the main control means to the predetermined state Holding means for holding, and the main control means controls the output port based on the lamp lighting / extinguishing state stored in the nonvolatile memory when returning from a hardware reset, while the lamp driving control means Is characterized in that the lamp is turned on when the output port of the main control means is in the predetermined state for a predetermined time longer than the time when the output port can be controlled from a hardware reset of the main control means. Projection-type image display device.   2. A projection display apparatus according to claim 1, wherein said holding means comprises a pull-up resistor interposed between said output port and a power source having a predetermined voltage to pull up said output port. 3. The predetermined time is set to a time required for the booster circuit to be completely driven after the output port of the main control means is set to the predetermined state. Projection image display device.

Images