JP2007293193A - Image projecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image projecting apparatus capable of securely storing information about the apparatus in case where a power source is shut off, without providing a detecting circuit specifically to detect the shutoff of the power source. <P>SOLUTION: The image projecting apparatus operates by receiving power supplied from an external power source, and projects an image by using light from a light source lamp 102. The image projecting apparatus includes: a detecting means 103e (108) for detecting the turning on or off of the light source lamp; a first control means 103 for controlling the turning on of the light source lamp by using the detecting means; and a capacitor 105. When the detecting means detects the switching off of the light source lamp from the on-state of it, a second control means 106 writes information about the apparatus into a storage means 107 by using power supplied from the capacitor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image projection apparatus such as a liquid crystal projector, and more particularly to an image projection apparatus having a function of storing apparatus information in a storage unit such as a nonvolatile memory when the power is turned off.

  An image projection apparatus such as a liquid crystal projector generally operates by receiving power supply from a commercial AC power source as an external power source. Various operations of the apparatus are controlled by control signals and data from the system control circuit.

  In such an image projection apparatus, when the power switch is turned off, various types of information related to the apparatus immediately before the power is turned off (hereinafter referred to as device information) is written and stored in a nonvolatile memory such as an EEPROM. The device information includes a setting mode, a system operation status, a cumulative lamp lighting time, and the like. By referring to such device information the next time you use the device and performing control and data settings, you can start using the same device state as the previous time when you use the device the next time, or display a message prompting you to replace the lamp. can do.

  However, if the power supply to the device is interrupted due to a power failure etc. just before the device information is written to the non-volatile memory, the device information will be lost and the device status at the previous use will be lost at the next use. Can not return to.

For this reason, conventionally, a method has been adopted in which a dedicated circuit for detecting a power failure is added to the device, and when the power failure is detected, the device information is immediately stored in a nonvolatile memory. For example, in Patent Document 1, a high voltage and a low voltage are generated from a single power source. When a power failure occurs, the power failure is detected by a voltage detection circuit provided on the high voltage side, and device information is written in a nonvolatile memory. A protection device that can be used for a projector or the like that performs processing is disclosed.
JP 2000-40037 (paragraphs 0019 to 0032, FIG. 1, etc.)

  However, the projectors disclosed in the related art and Patent Document 1 are provided with a dedicated detection circuit for detecting power interruption such as a power failure. For this reason, an increase in the number of parts and a complicated circuit configuration in the apparatus are inevitable.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image projection apparatus that can reliably store apparatus information at the time of power-off without providing a dedicated detection circuit for detecting power-off. .

  An image projection apparatus according to one aspect of the present invention operates by receiving power supply from an external power source, and projects an image using light from a light source lamp. The image projection device includes a detection unit that detects lighting / non-lighting of the light source lamp, a first control unit that controls lighting of the light source lamp using the detection unit, and information (device information) about the image projection device. Storage means capable of writing data, second control means for writing device information to the storage means, and a capacitor. The second control means performs the device information writing process to the storage means using the power supplied from the capacitor when the detection means detects that the light source lamp is switched from lighting to non-lighting. It is characterized by.

  Note that an image display system including the image projection apparatus and an image supply apparatus that supplies image information to the image projection apparatus also constitutes another aspect of the present invention.

  According to the present invention, the detection means that is originally used for the lighting control of the light source lamp by the first control means is also used for detecting power interruption such as a power failure. Thereby, it is possible to reliably store the device information at the time of power-off without providing a dedicated circuit for detecting power-off.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, FIG. 2 shows a schematic configuration of a liquid crystal projector as an image projection apparatus that is Embodiment 1 of the present invention.

  In FIG. 2, reference numeral 219 denotes a liquid crystal projector. A discharge lamp 102 such as a high-pressure mercury lamp serves as a light source for illuminating the liquid crystal panel 202. The liquid crystal panel 202 is provided for each color component such as R, G, and B, for example, and forms an image corresponding to the video signal. An image formed on the liquid crystal panel 202 is projected onto a projection surface such as a screen (not shown) by the projection lens 201. As the liquid crystal panel 202, either a reflection type or a transmission type can be used.

  Reference numeral 103 denotes a ballast as first control means for controlling lighting control of the lamp 102 and stable power supply after lighting. Reference numeral 101 denotes a power supply unit which supplies a high DC voltage to the ballast 103 using power from an external power supply (commercial AC power supply) or a DC operation to a system control circuit 106 and other processing / control systems described later. Or supply voltage.

  Reference numeral 210 denotes a selector that selects a desired image from a plurality of image signals input to the projector 219. The selector 210 selects one of video signals such as a video signal, a component signal, an analog RGB signal, and a digital RGB signal input via the connector 221 and the decoder 211. The connector 221 is connected to an image supply device such as a personal computer or various video equipment. The decoder 211 performs predetermined synchronization separation processing, analog-digital signal conversion, and the like on the video signal input from the connector 221.

  An image processing circuit 208 performs various image processing such as interlace / progressive conversion, frame rate conversion, resolution conversion, and aspect conversion on the video signal selected by the selector 210. At this time, a frame memory 209 as a work area is used as necessary.

  An on-screen display (OSD) image signal is synthesized by the image synthesis circuit 207 with the image signal subjected to the image processing. The OSD image is an image that displays information such as a menu, a pointer, and a message for selecting the function and operation mode of the projector.

  The video signal output from the image synthesis circuit 207 is sent to the panel driver 206. The panel driver 206 drives the liquid crystal panel 202 so that an image corresponding to the input video signal is formed on the liquid crystal panel 202.

  In addition, the projector 219 includes a communication control circuit 213 for performing communication with the personal computer 217. Through the communication control circuit 213, the computer 217 can be controlled from the projector 219, and conversely, the projector 219 can be controlled from the computer 217.

  Further, the projector 219 includes an operation panel 206 for setting an operation mode including a projection mode and selecting an operation content, and a remote control receiving circuit 214 for enabling control according to a signal from the remote controller 216. Is provided.

  The system control circuit 106 as the second control means is a program-controllable processor unit including a CPU, RAM, ROM and the like. The system control circuit 106 controls each circuit such as the power supply unit 101, the ballast 103, the image processing circuit 208, and the panel driver 206 via the internal line 218 including a system bus and I / O. Further, the system control circuit 106 acquires information from each circuit and writes / reads device information to / from a nonvolatile memory 107 such as an EEPROM. The device information here includes the projection mode and other setting modes, the system operation content and operation status, the cumulative lighting time of the lamp 102, and the like. By referring to such device information the next time the projector is used and performing control and data setting, the next time the projector is used, the use starts from the same state as the previous time, or a message prompting replacement of the lamp 102 is displayed. can do.

  FIG. 1 shows a configuration of a power supply system in projector 219 shown in FIG. 2 are given the same reference numerals as those in FIG.

  The power supply unit 101 receives power supply of AC100V (or AC120V, 240V, etc.) through a plug 111 inserted into the outlet of the commercial AC power supply 110. The power supply unit 101 supplies a DC high voltage (V1 voltage) such as DC370V to the ballast 103. The ballast 103 controls the power supply to the discharge lamp 102 as described above.

  Here, FIG. 5 shows the configuration of the ballast 103. Reference numeral 103a denotes a step-down circuit that steps down the V1 voltage supplied from the power supply unit 101 to a drive voltage (for example, 80V) of the lamp 102, and passes the drive voltage through a lamp drive circuit 103b connected to the electrode of the lamp 102. Supply to the lamp 102. Reference numeral 103c denotes a CPU as a ballast controller, which controls operations of the step-down circuit 103a and a trigger circuit 103d described later. The CPU 103c communicates with the CPU 106a in the system control circuit 106.

  The trigger circuit 103 d applies a trigger voltage of 10 k to 20 kV between the electrodes of the lamp 102 to start discharge (lighting) of the lamp 102. The trigger circuit 103d is provided with a switching element such as a thermistor, and a trigger voltage is applied between the lamp electrodes by the control of the switching element by the CPU 103c.

  Reference numeral 103f denotes a voltage dividing resistor. The CPU 103c detects the voltage of the lamp driving circuit 103b by the voltage dividing resistor 103f and controls the step-down circuit 103a so that the driving voltage becomes constant.

  Reference numeral 103e denotes a lighting sensor that detects lighting / non-lighting of the lamp 102. In the present embodiment, as the lighting sensor 103e, lighting / non-lighting of the lamp 102 is detected based on the presence or absence of a DC current flowing through the lamp driving circuit 103b when the lamp 102 is lit. As the lighting sensor 103e, a sensor that directly picks up a DC current flowing through the lamp driving circuit 103b may be used, or a sensor that indirectly detects the DC current flowing through the lamp driving circuit 103b may be used.

  The CPU 103c determines that the lamp 102 is lit when a DC current is flowing through the lamp driving circuit 103b and there is an output from the lighting sensor 103e. If no DC current flows through the lamp driving circuit 103b and there is no output from the lighting sensor 103e, it is determined that the lamp 102 is not lit. When the trigger voltage is applied between the lamp electrodes through the trigger circuit 103d and the output from the lighting sensor 103e is not obtained, the trigger circuit 103d is controlled so that the trigger voltage is applied again between the lamp electrodes. . In addition, the CPU 103c sends a signal indicating lighting / non-lighting of the lamp 102 detected by the lighting sensor 103e to the system control circuit 106.

  In FIG. 1, reference numeral 104 denotes a step-down circuit that steps down the V1 voltage from the power supply unit 101 to a V2 voltage such as 5V or 12V. A capacitor 105 is charged by applying the V2 voltage. The system control circuit 106 and the nonvolatile memory 107 operate with the V2 voltage.

  Reference numeral 108 denotes a signal line for transmitting a signal indicating lighting / non-lighting of the lamp 102 from the CPU 103 c in the ballast 103 to the system control circuit 106.

  Reference numeral 109 denotes a bus line for transferring information to be stored from the system control circuit 106 to the nonvolatile memory 107.

  Next, processing operations of the ballast 103 (CPU 103c) and the system control circuit 106 (CPU 106a) will be described with reference to FIG. These processing operations are executed in accordance with a computer program stored in a CPU 103c of the ballast 103 and a memory (not shown) in the system control circuit 106.

  In the ballast 103, the CPU 103c of the ballast 103 determines whether or not a power switch (not shown) of the projector is turned on (ON) in step S301. When the power switch is turned on, the process proceeds to step S302, the trigger circuit 103c is operated, and the trigger voltage is applied to the lamp 102.

  Next, CPU103c discriminate | determines whether the lamp | ramp 102 was lighted through the presence or absence of the output from the lighting sensor 103e by step S303. When the lamp 102 is lit, a signal indicating that the lamp 102 is lit (hereinafter referred to as a lighting signal) is sent to the system control circuit 106, and the process proceeds to step S304. On the other hand, if the lamp 102 is not lit, the process returns to step S302, and the trigger voltage is applied to the lamp 102 again.

  In step S304, the CPU 103c determines whether or not the power supply from the AC power source 110 is interrupted due to a power failure, breaker operation, disconnection of the plug 111 from the outlet, or the like. If the power supply is cut off, the lamp 102 is turned off in step S305. Here, the lamp 102 is turned off naturally in terms of power load when the supply of the driving voltage from the lamp driving circuit 103b is stopped.

  In step 306, the CPU 103c detects that the lamp 102 has been turned off due to the absence of the output from the lighting sensor 103e, and a signal indicating that the lamp 102 has not been turned on (hereinafter referred to as a non-lighting signal). 106.

  The CPU 106a of the system control circuit 106 determines whether or not a non-lighting signal is received from the ballast 103 in step S401. When the non-lighting signal is received, that is, when the state in which the lighting signal has been received is switched to the state in which the non-lighting signal has been received, the process proceeds to step S402.

  In step S402, it is determined whether or not writing (data saving) of device information (hereinafter referred to as data) to the nonvolatile memory 107 is being executed. If it is being executed, the process proceeds to step S405. On the other hand, if data saving is not being executed, the process proceeds to step S403.

  In step S403, the CPU 106a determines whether there is data that needs to be saved in a volatile memory (not shown) provided in the CPU 106a. If there is no data that needs to be saved, this process ends. On the other hand, if there is data that needs to be saved, the process proceeds to step S404 to start saving the data to the nonvolatile memory 107.

  Next, in step S405, the CPU 106a determines whether or not the data saving can be completed within the time until the system control circuit 106 stops after the AC power supply is shut off.

  Here, the relationship between the time until the operation of the system control circuit 106 stops after the AC power supply is shut off and the data save time will be described with reference to FIG.

  In FIG. 4, V1 and V2 are the supply voltage from the power supply unit 101 to the ballast 103 and the supply voltage to the system control circuit 106 and the nonvolatile memory 107, respectively. t indicates the time when the AC power supply is shut off (power failure).

  At time t, power supply from the AC power supply 110 to the power supply unit 101 is stopped. At the same time, the voltage V1 starts to drop. When the drop of the V1 voltage starts, the V1 voltage is not supplied to the ballast 103 and the lamp 102 is turned off. On the other hand, during this time, the voltage V2 gradually decreases due to the effect of power discharge from the capacitor 105.

  Here, the system control circuit 106 and the nonvolatile memory 107 are designed to operate normally up to a V2 ′ voltage (operation guarantee voltage: first voltage) lower than the V2 voltage. Therefore, the system control circuit 106 and the nonvolatile memory 107 can operate normally during the time from the time t until the voltage V2 drops to V2 '.

  The lighting signal input from the ballast 103 to the system control circuit 106 is switched to a non-lighting signal at time t + T ′ delayed by time T ′ from time t until the lamp 102 is turned off. In step S405, the system control circuit 106 determines whether or not the saving of the data that needs to be saved to the nonvolatile memory 107 is completed during the time T from the time t + T ′ until the voltage V2 drops to V2 ′. Determine.

  The time T can be calculated from the size of saved data in the nonvolatile memory 107 and the access speed of the nonvolatile memory 107. Then, the required capacity of the capacitor 105 can be determined from the time T and the amount of power consumed by the system control circuit 106, the nonvolatile memory 107, and other parts operating by the V2 voltage. If the power consumption during the time T ′ from the power failure time t until the actual non-lighting signal is output is so large that it cannot be ignored, the time T ′ is added to T to increase the required capacity of the capacitor 105. Just decide.

  If it is determined in step S405 that the data saving can be completed, the CPU 106a proceeds to step S406, continues the data saving, and saves the unsaved data in the nonvolatile memory 107.

  Thereby, necessary data can be automatically and reliably saved in the nonvolatile memory 107 when the AC power supply 110 is shut off. In addition, in this embodiment, the lighting sensor 103e that is originally provided for determining whether or not to reapply the trigger voltage to the lamp 102 is also used as a means for detecting whether or not the AC power is cut off. For this reason, data saving to the non-volatile memory 107 when the AC power supply 110 is shut off can be reliably performed without increasing the number of components or complicating the circuit.

  On the other hand, if the amount of data that needs to be saved is so large that the saving is not completed within time T, and it is determined in step S405 that the data saving cannot be completed, the process proceeds to step S407.

  In step S407, the CPU 106a performs a predetermined interruption process. In the interruption process, a checksum is added to the saved data so that at least the saved data can be used or referenced when the projector is used next time. Further, the previous data may be held until the saving of all data that needs to be saved is completed, and a checksum for handling the previous data as the current saved data may be added by the interruption process. .

  As a result, it is possible to prevent data necessary for the next use from being completely lost or destroyed.

  FIG. 7 shows a configuration of a power supply system in a projector that is Embodiment 2 of the present invention. In addition, the same code | symbol as Example 1 is attached | subjected to the component same as the component shown in Example 1 (FIG. 2).

  In the first embodiment, a sensor that detects the presence or absence of a DC current flowing in the lamp driving circuit is used as the lighting sensor. However, in this embodiment, the light receiving element 120 that detects light emitted from the lamp 102 is used as the lighting sensor. Yes.

  In this case as well, as in the first embodiment, the light receiving element 120 is originally provided to determine whether or not to apply the trigger voltage again to the lamp 102 in the ballast 103 ′. It is also used as a means for detecting whether or not it has been blocked. The processing operations of the ballast 103 'and the system control circuit 106 are the same as those described in the first embodiment.

  Also in the present embodiment, similarly to the first embodiment, the data can be surely saved to the non-volatile memory 107 when the AC power is shut off without causing an increase in the number of components or a complicated circuit. it can.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the contents described in the claims.

1 is a block diagram showing a configuration of a power supply system of a projector that is Embodiment 1 of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration of the projector according to the first embodiment. 6 is a flowchart illustrating processing operations in the projector according to the first embodiment. FIG. 6 is a diagram illustrating a voltage drop state when the power is shut off in the projector according to the first embodiment. FIG. 3 is a diagram illustrating a configuration of ballast in the projector according to the first embodiment. FIG. 5 is a block diagram illustrating a configuration of a power supply system of a projector that is Embodiment 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Power supply unit 102 Discharge lamp 103 Ballast 103e, 120 Lighting sensor 104 Step-down circuit 105 Capacitor 106 System control circuit 107 Non-volatile memory

Claims (6)

An image projection apparatus that operates by receiving power supply from an external power source and projects an image using light from a light source lamp,
Detecting means for detecting lighting / non-lighting of the light source lamp;
First control means for controlling lighting of the light source lamp using the detection means;
Storage means capable of writing information relating to the image projection apparatus;
Second control means for writing the information to the storage means;
And having a capacitor
The second control unit writes the information to the storage unit using the power supplied from the capacitor when the detection unit detects that the light source lamp is switched from lighting to non-lighting. An image projection apparatus characterized by   The first control means applies a trigger voltage for starting lighting of the light source lamp to the light source lamp, and detects non-lighting of the light source lamp using the detection means after application of the trigger voltage. The image projection apparatus according to claim 1, wherein a trigger voltage is applied to the light source lamp again.   The detection means is provided on a circuit connected to the light source lamp, and flows through the circuit when the light source lamp is turned on, and turns on / off the light source lamp according to the presence / absence of a current that does not flow through the circuit when the light source lamp is turned off. The image projection apparatus according to claim 1, wherein non-lighting is detected.   The image projection apparatus according to claim 1, wherein the detection unit is a light receiving element. The second control means operates normally upon receiving a power supply equal to or higher than the first voltage,
The second control means detects a switching from lighting to non-lighting of the light source lamp by the detection means, and in a state where power is supplied from the capacitor, a supply voltage to the second control means is 5. The process of writing the information into the storage unit is performed within a time period from when the voltage is higher than the first voltage to when the voltage drops to the first voltage. 6. The image projection apparatus described. An image projection device according to any one of claims 1 to 5,
An image display system comprising: an image supply device that supplies image information to the image projection device.