JP4183646B2 - Lamp control device - Google Patents

Description

  The present invention relates to a lamp control device, and is particularly applied to a projection-type image display device such as a liquid crystal projector. The lamp is turned on when a power-on operation is performed, and the lamp is turned off when a power-off operation is performed. The present invention relates to a lamp control device.

An example of a conventional lamp control device of this type is disclosed in Patent Document 1. According to this prior art, when a power-off operation is performed, video output is stopped and a timer counter is started. If the power-on operation is performed before the measurement time by the timer counter reaches a predetermined value, the timer counter is reset and video output is resumed. When the measurement time by the timer counter reaches a predetermined value, the projection lamp is turned off. Once the projection lamp is turned off, the power-on operation is prohibited for a predetermined time. As a result, the life of the projection lamp that is vulnerable to frequent switching between lighting and extinguishing can be extended.
Japanese Utility Model Publication No. 4-72234 [G03B 21/14, 21/00]

  However, in the conventional technique, since the grace period from the power-off operation to the lamp extinguishing is fixed, the operation characteristics of the operator are not reflected in the operation of the apparatus, and wasteful power may be consumed.

  Therefore, a main object of the present invention is to provide a lamp control device capable of extending the life of the lamp while avoiding unnecessary power consumption.

A lamp control device according to the invention of claim 1 is a lamp that shifts from an off state to an on state in response to a power-on operation, and that shifts from the on state to the off state in response to a power-off operation.
Measuring means for measuring a period from the current power-off operation to the next power-on operation;
A discriminating unit that discriminates whether or not a numerical value is below a threshold value for a minimum value among the latest N (N: integer greater than or equal to 2) measured values measured by the measuring unit; and a discrimination result of the discriminating unit is When it is affirmative, it comprises delay means for delaying the timing for shifting the lamp to the off state in response to the power-off operation over a predetermined period, and when the determination result of the determination means is negative Control means for quickly turning off the lamp in response to the operation is provided.

  The lamp transitions from the off state to the on state in response to the power on operation, and transitions from the on state to the off state in response to the power off operation. The period from the current power-off operation to the next power-on operation is measured by the measuring means. The discriminating unit discriminates whether or not the numerical value falls below a threshold value with respect to the minimum value among the latest measured N (N: an integer of 2 or more). Here, if the determination result is affirmative, the timing for shifting the lamp to the OFF state in response to the power-off operation is delayed for a predetermined period by the delay means.

  The latest N measured values indicating the period from the current power-off operation to the next power-on operation indicate the recent operation characteristics of the operator. The delay means delays the timing for shifting the lamp to the OFF state in consideration of such operation characteristics. This can extend the life of the lamp while avoiding wasteful power consumption.

  A lamp control device according to a second aspect of the present invention is dependent on the first aspect, and further includes a reduction means for reducing the brightness of the lamp at a time corresponding to a predetermined period. As a result, it is possible to avoid a situation in which the current state is misunderstood as the power-on state.

  A lamp control device according to a third aspect of the present invention is dependent on the second aspect, and further comprises return means for restoring the brightness of the lamp when a power-on operation is performed at a time corresponding to a predetermined period.

  A lamp control device according to a fourth aspect of the present invention is dependent on any one of the first to third aspects, and includes a storage unit for storing a measurement value by the measurement unit, and a latest N measurement values stored by the storage unit. Detection means for detecting a minimum value from the detection means, and the determination means performs a determination operation on the minimum value detected by the detection means.

  A liquid crystal projector according to a fifth aspect of the invention includes the lamp control device according to any one of the first to fourth aspects.

  According to the present invention, the timing for shifting the lamp to the OFF state is controlled based on the latest N measured values indicating the period from the current power-off operation to the next power-on operation. This can extend the life of the lamp while avoiding wasteful power consumption.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  Referring to FIG. 1, the liquid crystal projector of this embodiment includes an AC / DC converter 14. The commercial AC voltage taken in through the AC plug 12 is converted into a DC voltage by the AC / DC converter 14. The backup power supply is charged by a DC voltage from the AC / DC converter 14 and always starts the CPU 24.

  When a power-on operation is performed by the key input device 26 in a state where the lamp 22 is turned off and the cooling fan 20 is disabled, the CPU 24 turns on the DC / DC converters 18a and 18b included in the power circuit 18. Each of the DC / DC converters 18a and 18b converts the DC voltage from the AC / DC converter 14 into a video processing DC voltage and a lamp DC voltage, and the converted DC voltage is converted into a video processing system 32 and a lamp (metal halide lamp). 22 As a result, the video processing system 32 is activated and the lamp 22 is turned on.

  The timer counter 28 is activated in response to the previous power-off operation. The CPU 24 stops the timer counter 28 in response to the power-on operation, and registers the current count value of the timer counter 28 in the register 30r formed in the flash memory 30. Referring to FIG. 2, register 30r has 50 columns, and an identification number is assigned to each column. The count value of the timer counter 28 is cyclically written to each column in the order according to the identification number. As a result, the latest 50 count values are secured in the register 30r.

  The CPU 24 detects the minimum count value from the count values registered in the register 30r, and sets the extension flag exflg to “1” or “0” according to the numerical value indicated by the minimum count value. When the minimum count value is less than “300 seconds”, the extension flag exflg is set to “1”. When the minimum count value is “300 seconds” or more, the extension flag exflg is set to “0”. Note that the initial value set in the column of the register 30r is “0”. Therefore, the extension flag exflg is always set to “1” for the first 50 times.

  Returning to FIG. 1, when an image reproduction operation is performed by the key input device 26 after the power-on operation, the CPU 24 instructs the video processing system to perform a reproduction process. The I / F circuit 38 reads the video data from the recording medium 46 and supplies the read video data to the video signal circuit 36. The video signal circuit 36 converts the supplied video data into RGB signals, and inputs the converted RGB signals to the liquid crystal drive circuit 34.

  The liquid crystal drive circuit 34 drives the liquid crystal panel 40 based on the R component included in the RGB signal, drives the liquid crystal panel 42 based on the G component included in the RGB signal, and based on the B component included in the RGB signal. Then, the liquid crystal panel 44 is driven. The back of the liquid crystal panels 40, 42 and 44 is irradiated with light from the lamp 22, whereby a desired image appears on the screen.

  When the power-off operation is performed by the key input device 26, the CPU 24 turns off the DC / DC converter 18a so as to disable the video processing system 32, and measures the time of the timer counter 28 so as to measure the time until the next power-on operation. Reset and start.

  The CPU 24 also determines the state of the extension flag exflg, and if exflg = 1, sets the brightness of the lamp 22 to the minimum value for 300 seconds, and then turns off the DC / DC converter 18b to turn off the lamp 22. To do. On the other hand, if exflg = 0, the CPU 24 immediately turns off the DC / DC converter 18b. After the lamp 22 is turned off, the CPU 24 turns on the DC / DC converter 18c for 90 seconds to start the cooling fan 20. The unlit lamp 22 is forcibly cooled by the cooling fan 20.

  If the power-on operation is performed while the lamp 22 is lit at the minimum brightness, the brightness of the lamp 22 is returned to the maximum value.

  As described above, whether the lamp 22 is immediately turned off or kept on for a predetermined period when the power-off operation is performed is determined based on the past power-on / off operation characteristics. Thereby, unnecessary lighting of the lamp 22 is avoided as much as possible, and power consumption can be reduced. Even when the lamp 22 is kept lit, the brightness is set to the minimum value, so that the operator who performed the power-off operation is not confused.

  The CPU 14 is a multitask CPU equipped with a multitask OS such as μITRON, and executes a plurality of tasks including the power control task 1 shown in FIG. 3 and the power control task 2 shown in FIG. 4 in parallel. A control program corresponding to this flowchart is stored in the flash memory 30.

  Referring to FIG. 3, in step S1, it is determined whether or not a power-on operation has been performed. If “YES” here, the process proceeds to a step S3 to determine whether or not the cooling fan 20 is being activated. If the cooling fan 20 is being activated, the process returns to step S1, and if the cooling fan 20 is in a stopped state, the process proceeds to step S5.

  In step S5, it is determined whether or not the lamp 22 is lit. If the lamp 22 is off, the DC / DC converter 18b is turned on to turn on the lamp 22 in step S7 and then the process proceeds to step S11. If the lamp 22 is on, the brightness of the lamp 22 is turned on in step S9. Is set to the maximum value, and the process proceeds to step S11.

  In step S11, the DC / DC converter 18a is turned on to start the video processing system, and in step S13, the timer counter 28 is stopped. In step S15, the count value of the timer counter 28 is registered in the register 30r shown in FIG. The count value is cyclically written to each column in the order according to the identification number.

  In step S17, the minimum count value is detected from the register 30r. In step S19, it is determined whether or not the minimum count value is less than "300 seconds". If YES here, the extension flag exflg is set to “1” in step S21. If NO, the extension flag exflg is set to “0” in step S23. When the process of step S21 or S23 is completed, it is determined whether or not a power-off operation has been performed in step S25, and when YES is determined, the process returns to step S1.

  Referring to FIG. 4, it is determined in step S31 whether or not a power-off operation has been performed. If "YES" here, the DC / DC converter 18a is turned off to disable the video processing system 32 in a step S33, and the timer counter 28 is reset and started in a step S35. The count value of the timer counter 28 indicates the off period of the video processing system 32.

  In step S37, the state of the extension flag exflg is determined. If the extension flag exflg is "1", the brightness of the lamp 22 is set to the minimum value in step S39. In step S41, it is determined whether or not 300 seconds have elapsed. In step S42, it is determined whether or not a power-on operation has been performed. If 300 seconds elapse before the power-on operation is performed, the process proceeds to step S43, and if power-on operation is performed before 300 seconds elapses, the process returns to step S31. On the other hand, if it is determined in step S37 that the extension flag exflg is “0”, the process proceeds to step S43.

  In step S43, the DC / DC converter 18b is turned off to turn off the lamp 22, and in step S45, the DC / DC converter 18c is turned on to start the cooling fan 20. When 90 seconds have elapsed from the start of the cooling fan 20, the process proceeds from step S47 to step S49, and the DC / DC converter 18c is turned off to disable the cooling fan 20. In step S51, it is determined whether or not a power-on operation has been performed. If YES, the process returns to step S31.

  As can be understood from the above description, the lamp 22 shifts from the off state to the on state in response to the power-on operation by the key input device 26, and from the on state to the off state in response to the power-off operation by the key input device 26. Migrate to The timer counter 28 measures a period from the current power-off operation to the next power-on operation. The measurement value (count value) is registered in a register 30 r formed in the flash memory 30. The CPU 24 detects the minimum count value from the latest 50 count values registered in the register 30r (S17), and determines whether or not this minimum count value falls below a threshold value (= 300 seconds) (S19). ). If the determination result is affirmative, the CPU 24 delays the timing for shifting the lamp 22 to the off state in response to the power-off operation over a predetermined period (= 300 seconds) (S41). The CPU 24 also reduces the brightness of the lamp 22 during this delay period (S39).

  The latest 50 count values registered in the register 30r indicate the latest power on / off operation characteristics. The CPU 24 delays the timing at which the lamp 22 is shifted to the off state in consideration of the operation characteristics. This can extend the life of the lamp while avoiding unnecessary power consumption. Further, by reducing the brightness of the lamp 22 during the delay period, it is possible to avoid a situation where the current state is mistaken as the power-on state.

It is a block diagram which shows the structure of one Example of this invention. FIG. 3 is an illustrative view showing one example of a register applied to the embodiment in FIG. 1; It is a flowchart which shows a part of operation | movement of CPU applied to the FIG. 1 Example. It is a flowchart which shows a part of other operation | movement of CPU applied to the FIG. 1 Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal projector 18 ... Main power supply circuit 20 ... Lamp power supply circuit 22 ... Light source lamp 24 ... CPU
26 ... Power switch 28 ... Timer counter 30 ... Flash memory 32 ... Cooling fan

Claims (5)

A lamp that transitions from an off state to an on state in response to a power on operation, and that transitions from the on state to the off state in response to a power off operation;
Measuring means for measuring a period from the current power-off operation to the next power-on operation;
A discriminating unit that discriminates whether or not a numerical value is below a threshold value for a minimum value among the latest N (N: integer greater than or equal to 2) measured values measured by the measuring unit; and a discrimination result of the discriminating unit is A delay means for delaying a timing for shifting the lamp to the OFF state in response to the power OFF operation when affirmative;
In addition, the lamp control apparatus further comprises a control unit that quickly turns off the lamp in response to the power-off operation when the determination result of the determination unit is negative . The lamp control device according to claim 1, further comprising a reducing unit that reduces the brightness of the lamp at a time corresponding to the predetermined period. The lamp control device according to claim 2, further comprising return means for restoring the brightness of the lamp when the power-on operation is performed at a time corresponding to the predetermined period. Storage means for storing the measurement value by the measurement means, and detection means for detecting the minimum value from the latest N measurement values stored by the storage means,
The lamp control device according to claim 1, wherein the determination unit performs a determination operation on a minimum value detected by the detection unit. A liquid crystal projector comprising the lamp control device according to claim 1.

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