JP5177836B2 - Projector and light source protection method - Google Patents

Description

  The present invention relates to a projector and a light source protection method for specifying a turn-off time from when a light source is turned off to when it is turned on again by the amount of charge of a capacitor.

  In general, when a lamp for projection display provided in a projector is lit in a high temperature state, there is a high possibility that deterioration will be accelerated. Therefore, there is a method of determining whether or not the lamp is in a high temperature state based on the time from when the lamp is extinguished until it is turned on again (extinguishing time). In this method, when the turn-off time is shorter than a predetermined time, the lamp is turned on after being cooled by a cooling means such as a fan.

  In the above method, the charge amount of the capacitor may be used to determine whether or not the turn-off time is shorter than a predetermined time. In this case, the capacitor is arranged in the circuit so as to discharge when the lamp is turned off. Therefore, the charge amount of the capacitor during the extinguishing time decreases with the passage of time. That is, the voltage value of the capacitor decreases with time.

  Therefore, if a threshold value corresponding to the above-mentioned predetermined time is determined in advance and the voltage value of the capacitor after the turn-off time is larger than the threshold value, it is determined that the turn-off time is shorter than the predetermined time. The Rukoto.

  A projector that actually measures the lamp turn-off time has been proposed, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-274747.

  The projector described in Patent Document 1 includes a backup power supply for making a CPU (Central Processing Unit) always operable, thereby making it possible to measure the actual turn-off time.

  In the projector described in Patent Document 1, when an operation for turning off the power is performed and the lamp shifts to the off state, the CPU causes the timer counter to measure the off time. The turn-off time measured by the timer counter is stored in the memory by the CPU. At this time, a plurality of extinguishing periods measured in the past are stored in the memory.

  When the CPU confirms that all of the turn-off times stored in the memory are longer than the predetermined time, the CPU immediately cools the lamp with a fan and turns it off.

  On the other hand, if at least one piece of data shorter than the predetermined time is included, the CPU cools the lamp and turns it off after a predetermined period. At this time, if an operation of turning on the power is performed before the predetermined period has elapsed, the CPU restarts the projection display.

As described above, the projector described in Patent Document 1 frequently turns on and off the lamp by delaying the lamp after a predetermined period of time when the lamp off time is shorter than the predetermined time in the past. This prevents switching and extends the lamp life.
JP 2005-274747 A

  When specifying the lamp extinguishing time based on the amount of charge on the capacitor, the capacity of the capacitor varies due to individual differences or changes over time when it is determined whether or not the lamp is cooled based on a predetermined threshold. In this case, there is a possibility that the voltage value of the capacitor is smaller than the threshold value when the turn-off time is originally required to be cooled. Then, it is assumed that the lamp is lit without being cooled despite the high temperature state, and at this time, the operation for preventing the lamp from being deteriorated is not performed.

  In the projector described in Patent Document 1, since the actual turn-off time is measured by the time counter, it is considered that the above-described problem does not occur. However, the projector described in Patent Document 1 must always supply power to the CPU even when projection display is not performed in order to measure the turn-off time. As a result, it can be considered that the power consumption of the projector increases.

  SUMMARY An advantage of some aspects of the invention is that it provides a projector and a light source protection method capable of extending the life of a light source with low power consumption.

In order to achieve the above object, a projector according to the present invention provides:
A projector comprising: a cooling unit; and a control unit that determines whether or not the light source is turned on after the light source is cooled by the cooling unit when the light source is turned on, based on a charge amount of a capacitor that is discharged when the light source is turned off. There,
Have memory,
When the light source is turned on, the control unit sets the capacitor to a first time charge state based on a time required for charging of the capacitor to be completed, and based on a turn-off time that requires cooling of the light source. a charge state after the second time discharge state, the charge amount of the capacitor at the discharge state ends is measured and stored in the memory, when turning on the light source, the charge amount of the capacitor the memory If the charge amount exceeds the stored charge amount, the light source is cooled by the cooling means.

  Moreover, it is good also as providing the switch which switches to the charge state and discharge state of the said capacitor based on control of the said control part when the said light source is a lighting state.

  The control unit stores a flag indicating whether or not a charge amount at the end of the discharge state is measured in the memory, and the flag stored in the memory is turned on when the light source is turned on. In the case where it is indicated that the measurement is not performed, the cooling unit may cool the light source.

  In the present invention, the turn-off time from when the light source is turned off to when it is turned on again is specified by the amount of charge of the capacitor. When the light source is turned on, the capacitor is charged for the first time, and is charged after being discharged for the second time. Further, the charge amount of the capacitor at the end of the discharge state is measured and stored in the memory. When the light source is turned on, the light source is cooled if the charge amount of the capacitor exceeds the charge amount stored in the memory.

  Every time the light source is turned on, the charge amount of the capacitor, which is a criterion for determining whether or not to cool the light source, is measured and the reference value is updated. Thus, the light source turn-off time is specified with high accuracy without being affected by the above.

  Further, since the charge amount of the capacitor is measured when the light source is in a lighting state, it is not always necessary to supply power to the control unit.

  According to the present invention, since the light-off time of the light source is specified with high accuracy without always supplying power, it is possible to extend the life of the light source with low power consumption.

  An embodiment of a projector according to the present invention will be described.

  FIG. 1 is a schematic diagram showing the configuration of the projector of this embodiment. In this embodiment, the configuration and operation for performing the projection display are the same as those of the conventional projector, and thus detailed description thereof is omitted here.

  As shown in FIG. 1, the projector according to the present embodiment includes a capacitor 1, a control unit 2, a memory 3, a switch 4, a diode 5, a resistor 6, a fan 7, and a lamp 8. It is.

  The capacitor 1 is for specifying the extinguishing time of the lamp 8, one of which is connected to the control unit 2 together with the cathode of the backflow preventing diode 5, and the other is grounded. Further, a discharging resistor 6 is connected to the capacitor 1 in parallel.

  The control unit 2 includes a CPU 11 that controls the operation of each unit of the projector according to the present embodiment in accordance with a program, and an analog-to-digital converter 12 that measures a voltage value indicating the charge amount of the capacitor 1.

  The switch 4 is for switching whether or not to supply current to the capacitor 1 by ON and OFF operations. One of the switches 4 is connected to a power source 10 that supplies current to the projector, and the other is connected to the anode of the diode 5. Yes. The switch 4 performs an on / off operation based on the control of the CPU 11.

  The memory 3 stores a threshold value corresponding to a predetermined time. The predetermined time is determined in advance based on a turn-off time that requires cooling by the fan 7 when the lamp 8 is turned on. The memory 3 stores a program for operating the CPU 11.

  The fan 7 cools the lamp 8 based on the control of the CPU 11.

  The lamp 8 is turned on or off based on the control of the CPU 11.

  Next, the operation of the projector of this embodiment will be described.

  First, an operation for storing a threshold value in the memory 3 will be described.

  When the projector is activated and the lamp 8 is turned on, the CPU 11 turns on the switch 4. Then, a current is supplied from the power source 10 to the capacitor 1 via the diode 5, and the capacitor 1 is charged. At this time, the time for the CPU 11 to turn on the switch 4 is determined in advance based on the time required for the charging of the capacitor 1 to end.

  Subsequently, the CPU 11 turns off the switch 4 and starts measuring time. Then, the capacitor 1 starts discharging.

  When the measurement time reaches a predetermined time, the CPU 11 causes the analog-digital converter 12 to measure the voltage value of the capacitor 1. Then, the analog-digital converter 12 measures the voltage value of the capacitor 1 and outputs it to the CPU 11. The CPU 11 stores the voltage value input from the analog-to-digital converter 12 in the memory 3 as a threshold value and performs a reset process for the measurement time.

  When the threshold value is stored in the memory 3 in this way, the CPU 11 turns on the switch 4 to charge the capacitor 1 again.

  Next, the operation of the projector when the lamp 8 is turned off and then turned on will be described.

  When the projector is restarted, the analog-digital converter 12 measures the voltage value of the capacitor 1 and outputs it to the CPU 11. At this time, the CPU 11 turns off the switch 4 to stop the supply of current from the power supply 10 to the capacitor 1.

  When a voltage value is input from the analog-digital converter 12, the CPU 11 compares the voltage value with a threshold value stored in the memory 3. When the voltage value input from the analog / digital converter 12 is larger, the CPU 11 starts the fan 7 to cool the lamp 8. Thereafter, the CPU 11 turns on the lamp 8.

  When the lamp 8 is turned on, the CPU 11 turns on the switch 4 for a predetermined time to charge the capacitor 1. Subsequently, the CPU 11 stores the voltage value of the capacitor 1 measured by the analog-digital converter 12 in the memory 3 when the switch 4 is turned off again and a predetermined time is reached. At this time, the threshold value is updated.

  Note that a flag indicating whether or not the voltage value of the capacitor 1 is measured by the analog-digital converter 12 may be set. In this case, the value of the flag is stored in the memory 3, and the CPU 11 changes the value. Here, when the value of the flag is “1”, it indicates that the voltage value of the capacitor 1 has been measured. On the other hand, “0” indicates that the voltage value of the capacitor 1 is not measured.

  When the above-described flag is set, when the lamp 8 is turned on and the lamp is turned off when the switch 4 is turned off, the projector is turned off with the flag value being “0”. In this case, when the CPU 11 confirms that the value of the flag stored in the memory 3 is “0” when the projector is restarted, the fan 7 is started and the lamp 8 is cooled. Thereafter, the lamp 8 is turned on.

  When the voltage value of the capacitor 1 is measured after the lamp 8 is turned on, the CPU 11 changes the value of the flag stored in the memory 3 from “0” to “1”.

  In this way, when the flag as described above is set, if the threshold voltage and the turn-off time are unknown because the voltage value of the capacitor is not measured by the analog-to-digital converter 12, the lamp is turned on after being cooled. Therefore, it is possible to prevent the lamp from deteriorating and to further extend the life.

  In this embodiment, the turn-off time from when the light source is turned off to when it is turned on again is specified by the amount of charge of the capacitor. When the light source is turned on, the capacitor is charged for the first time, and is charged after the second time is discharged. Further, the charge amount of the capacitor at the end of the discharge state is measured and stored in the memory. When the light source is turned on, the light source is cooled if the charge amount of the capacitor exceeds the charge amount stored in the memory.

  Every time the light source is turned on, the charge amount of the capacitor, which is a criterion for determining whether or not to cool the light source, is measured and the reference value is updated. Thus, the light source turn-off time is specified with high accuracy without being affected by the above.

  Further, since the charge amount of the capacitor is measured when the light source is in a lighting state, it is not always necessary to supply power to the control unit.

  According to the present embodiment, since the light-off time of the light source is specified with high accuracy without always supplying power, it is possible to extend the life of the light source with low power consumption.

It is the schematic which shows the structure of the projector of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor 2 Control part 3 Memory 4 Switch 5 Diode 6 Resistance 7 Fan 8 Lamp 10 Power supply 11 CPU
12 Analog to digital converter

Claims (5)

A projector comprising: a cooling unit; and a control unit that determines whether or not the light source is turned on after the light source is cooled by the cooling unit when the light source is turned on, based on a charge amount of a capacitor that is discharged when the light source is turned off. There,
Have memory,
When the light source is turned on, the control unit sets the capacitor to a first time charge state based on a time required for charging of the capacitor to be completed, and based on a turn-off time that requires cooling of the light source. a charge state after the second time discharge state, the charge amount of the capacitor at the discharge state ends is measured and stored in the memory, when turning on the light source, the charge amount of the capacitor the memory The projector is characterized in that the cooling means cools the light source when the amount of charge stored in the projector exceeds the charge amount. The projector according to claim 1, wherein
A projector comprising: a switch that switches between a charged state and a discharged state of the capacitor based on control of the control unit when the light source is in a lighting state. In the projector according to claim 1 or 2,
The control unit stores a flag indicating whether or not a charge amount at the end of the discharge state is measured in the memory, and the flag stored in the memory is turned on when the light source is turned on. The projector is characterized in that the cooling means cools the light source when the measurement is not performed. Whether to turn on after cooling the light source when turning on the light source, is a light source protection method for determining by the amount of charge of the capacitor discharged when the light source is turned off,
When the light source is turned on , the capacitor is set to a first time charge state based on a time required for charging of the capacitor to be completed , and a second time discharge based on a turn-off time requiring cooling of the light source. and state of charge after the state, measuring the amount of charge of the capacitor when the discharge state ends,
When turning on the light source, compare the charge amount of the capacitor with the measured charge amount,
When the charge amount of the capacitor exceeds the measured charge amount, the light source is cooled.
A method of protecting a light source. The light source protection method according to claim 4,
If the charge amount at the end of the discharge state has not been measured, the light source is cooled when the light source is turned on,
A method of protecting a light source.

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