JP2008122746A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of calculating a proper time left until the end of the lifetime of a discharge lamp reaches, taking into account of the characteristics of the discharge lamp. <P>SOLUTION: The display apparatus includes: a time measuring section 118, which measures the usage time of the discharge lamp 30 from the beginning of its use; a lamp voltage upper-limit storage section 123, which stores the lamp voltage upper limit, or the upper limit of the lamp voltage, to which the discharge lamp can be operated; a function storage section 122, which stores a lamp voltage function estimating a change with the lapse of use time of the lamp voltage; and a remaining time calculating section 124, which calculates the difference between the first time derived from the lamp voltage upper limit and the lamp voltage function and the use time measured by the time measuring section, as the remaining time for which the discharge lamp is usable. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device that projects an image using a discharge lamp.

  Conventionally, each time an illumination lamp (discharge lamp) is lit, the terminal voltage (lamp voltage) is detected, and the difference from the terminal voltage detected at the previous lighting recorded in the memory is obtained. A projection display device that determines that the life of an illumination lamp is short when it is smaller than a predetermined value is known (Patent Document 1). However, Patent Document 1 does not consider detecting the remaining time until the lifetime of the illumination lamp.

  On the other hand, a technique for calculating the remaining time until the lifetime of the light source lamp (discharge lamp) is disclosed. For example, the replacement time of the light source lamp is stored, the accumulated use time of the light source lamp is counted, and the remaining use time is obtained by subtracting the accumulated use time from the expected replacement time. A projector that displays information indicating the above has been proposed (Patent Document 2).

JP 2002-122940 A JP 2002-287243 A

  It is known that a discharge lamp is worn by electrodes due to long-term lighting, and the distance between the electrodes becomes long due to wear, and the lamp voltage increases accordingly. When the lamp voltage reaches a predetermined value determined as the specification of the discharge lamp, it is determined that the life of the discharge lamp is reached, and the use of the discharge lamp is stopped to ensure safety. However, the rise change with time of the lamp voltage has different characteristics depending on the type and individual difference of the discharge lamp, and the remaining time until the lifetime is greatly influenced by the characteristics of the lamp voltage. Therefore, the technique described in Patent Document 2 has a problem in terms of calculating an appropriate remaining time because such characteristics of the discharge lamp are not taken into consideration.

  The present invention has been made to solve such a problem, and provides a display device capable of calculating an appropriate remaining time until the life of the discharge lamp in consideration of the characteristics of the discharge lamp. Objective.

  In order to achieve the above object, a display device of the present invention is a display device including a discharge lamp, and includes a time measuring unit that measures a usage time from the start of use of the discharge lamp, and an upper limit at which the discharge lamp can operate. A lamp voltage upper limit storage unit that stores a lamp voltage upper limit value that is a lamp voltage of the lamp, a function storage unit that stores a lamp voltage function that predicts a change with the passage of the lamp voltage usage time, a lamp voltage upper limit value and a lamp And a remaining time calculating unit that calculates a difference between the first time derived from the voltage function and the usage time measured by the time measuring unit as a remaining usable time of the discharge lamp. .

  According to such a display device, the remaining time calculation unit is a first time as a time when the lamp voltage function predicted to change with the passage of the lamp voltage usage time stored in the function storage unit reaches the lamp voltage upper limit value. The remaining time that can be used for the discharge lamp is calculated by calculating the difference between this time and the usage time measured by the time measuring unit. Therefore, the display device can calculate an appropriate remaining time corresponding to the characteristics of the discharge lamp by using the lamp voltage function. Here, the usage time from the start of use means the cumulative time of the time when the discharge lamp was actually lit from the start of use.

  In the display device, the display device further includes a lamp voltage detection unit that detects a lamp voltage when the discharge lamp is driven, a lamp voltage that is detected by the lamp voltage detection unit, and a lamp voltage that stores a usage time at the time of detection. It is preferable to include a storage unit and a function generation unit that generates a lamp voltage function based on the lamp voltage and usage time stored in the lamp voltage storage unit.

  According to such a display device, the lamp voltage storage unit stores the lamp voltage detected by the lamp voltage detection unit and the usage time at the time of detection, and the function generation unit is based on the stored lamp voltage and usage time. Generate a ramp voltage function. Therefore, since the function generation unit generates a lamp voltage function corresponding to the characteristics of the discharge lamp being used, the remaining time corresponding to the discharge lamp being used can be calculated more accurately. For example, when the least square method is used to generate the lamp voltage function, the detected lamp voltage can be approximated to the lamp voltage function with high accuracy. Further, the least square method is a generally known approximation method, and it is easy to realize the processing.

  In the display device, the lamp voltage detection unit detects the lamp voltage at every predetermined usage time interval, and the lamp voltage storage unit calculates the lamp voltage and the usage time at the detection at every predetermined usage time interval. Preferably, the function generation unit stores the lamp voltage function based on the lamp voltage and the usage time stored in the lamp voltage storage unit at each predetermined usage time interval.

  According to such a display device, the lamp voltage detector detects the lamp voltage at every predetermined usage time interval, the lamp voltage storage unit stores the lamp voltage and the usage time at the time of detection, and the function generator is the lamp Generate a voltage function. Therefore, the function generator can continue to generate a lamp voltage function that follows the change in the lamp voltage of the discharge lamp being used.

  In the display device, it is preferable that the function generating unit stops generating the ramp voltage function when the remaining time calculated by the remaining time calculating unit is equal to or less than a predetermined first remaining time.

  According to such a display device, the function generation unit stops generating the lamp voltage function for each predetermined use time interval when the remaining time becomes equal to or less than the predetermined first remaining time. Here, the predetermined first remaining time is a time at which the fluctuation of the lamp voltage function generated by the function generation unit is reduced and is assumed to be substantially fixed. The lamp voltage increases as the usage time elapses. Further, since the lamp voltage function is generated by using, for example, the least square method using the lamp voltage and the usage time data, if the number of data increases as the usage time elapses, the generated lamp voltage function varies less. It becomes almost fixed. In other words, the generation of the lamp voltage function is stopped after the generated lamp voltage function is substantially fixed. Thereby, since the process which produces | generates a lamp voltage function can be abbreviate | omitted, the load of a process can be reduced. When it is determined that the remaining time is equal to or less than the predetermined first remaining time, the lamp voltage function generated immediately before is stored, and after the generation of the lamp voltage function is stopped, the stored lamp voltage function is used. To calculate the remaining time.

  In the display device, the display device preferably includes a first display unit that displays the remaining time calculated by the remaining time calculation unit.

  According to such a display apparatus, it has a 1st display part which displays the remaining time which the remaining time calculation part calculated. Therefore, the display device can inform the user of the remaining time.

  Further, in the above display device, the display device displays a second display for prompting replacement of the discharge lamp in use when the remaining time calculated by the remaining time calculation unit is equal to or less than a predetermined second remaining time. It is preferable to have a display portion.

  According to such a display device, when the remaining time calculated by the remaining time calculating unit is equal to or less than a predetermined second remaining time, a display for prompting replacement of the discharge lamp being used is displayed on the second display unit. Do it. The predetermined second remaining time is a time that requires replacement of the discharge lamp determined from the specification of the discharge lamp. Therefore, the display device can notify the user when the remaining time is a time that requires replacement of the discharge lamp.

  In the display device, the display device preferably turns off the discharge lamp when the remaining time calculated by the remaining time calculation unit is 0 or less.

  According to such a display device, when the remaining time calculated by the remaining time calculation unit is 0 or less, the discharge lamp is turned off. As a result, the discharge lamp that has reached the end of its life can be extinguished, so that the use of the discharge lamp can be limited to a voltage within the rated specification range, and the safety in using the discharge lamp can be maintained.

  In the display device, the discharge lamp is configured as a lamp unit. The lamp unit preferably includes a lamp information memory, and the lamp information memory preferably includes a lamp voltage storage unit and a function storage unit.

  According to such a display device, the lamp unit includes the discharge lamp and the lamp information memory. The lamp information memory includes a lamp voltage storage unit and a function storage unit. As a result, a lamp information memory is provided for each lamp unit. Therefore, when the lamp unit needs to be replaced, the remaining time inherent to the discharge lamp can be obtained by using the lamp information memory of the lamp unit after replacement. Can be calculated.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a circuit block diagram showing the internal configuration of the projector according to the present embodiment. In the present embodiment, the display device is a projector 100 using the discharge lamp 30 as a light source. The internal configuration of the projector 100 will be described with reference to FIG.

  The projector 100 includes a power supply unit 10, a ballast 20, a discharge lamp 30, a lamp information memory 31, a CPU 40, a RAM 50, a ROM 60, a ballast-main board interface 70, a video control processing unit 80, a video. An input unit 110 and a video projection unit 113 are provided. In the present embodiment, the CPU 40, the RAM 50, the ROM 60, the ballast-main board interface 70, the video control processing unit 80, and the video input unit 110 are mounted on the main board. FIG. 1 shows a screen 200 and an external video output device 300 outside the projector 100.

Next, the circuit operation of the projector 100 will be described with reference to FIG.
The power supply unit 10 receives a commercial power supply such as AC 100 V and generates a DC power supply voltage necessary for various operations of the projector 100 and a DC power supply voltage for operating the ballast 20. The ballast 20 is a device that drives the discharge lamp 30 to light. The discharge lamp 30 functions as a light source for the projector 100.

  The discharge lamp 30 and the lamp information memory 31 are configured as a lamp unit, and the lamp information memory 31 is provided in the lamp unit via a material having low thermal conductivity so as not to be affected by the heat of the discharge lamp 30. ing. As the material having low thermal conductivity, for example, plastic is used, and the distance between the discharge lamp 30 and the lamp information memory 31 is increased. The lamp unit is detachable from the projector 100. When the lamp unit is attached to the projector 100, the discharge lamp 30 is connected to the ballast 20, and the lamp information memory 31 is mounted on the main board via a connector or the like. Here, the lamp information memory 31 is a non-volatile memory, and is a flash ROM in this embodiment. The lamp information memory 31 stores information on the use time, the lamp voltage, and the lamp voltage function, which will be described later, as individual information of the discharge lamp 30 that also constitutes the lamp unit.

  The lamp information memory 31, the CPU 40, the RAM 50, the ROM 60, and the video control processing unit 80 are connected to each other by a bus line on the main board. The ROM 60 includes, for example, a program for lamp control, a program for generating a lamp voltage function, a program for calculating the remaining usable time of the lamp, a program for video control, a program for OSD (On Screen Display) processing, and video A program for projecting is stored. The CPU 40 executes these programs while using the RAM 50 as a work area. The ballast-main board interface 70 is an interface that transmits a lamp voltage detection instruction signal from the CPU 40 to the ballast 20 and receives lamp voltage information detected by the ballast 20.

  The video input unit 110 inputs a video signal from the external video output device 300. The video control processing unit 80 processes the video signal input by the video input unit 110 as necessary, and superimposes the OSD display on the video. The video projection unit 113 projects the video signal output from the video control processing unit 80 onto the screen 200 as a video.

  FIG. 2 is a circuit block diagram showing the internal configuration of the ballast of the projector. The internal structure of the ballast of the projector 100 will be described using FIG.

  The ballast 20 includes an EMI filter 21, a down converter 22, an inverter circuit 23, and an igniter circuit 24. The ballast 20 includes a voltage detection circuit 25, an A / D converter 26, a communication circuit 27, and a ballast control circuit 28 as a ballast control unit.

Next, the circuit operation of the ballast 20 will be described with reference to FIG.
The DC voltage input from the power supply unit 10 is reduced in noise by the EMI filter 21 and stepped down by the down converter 22. The stepped-down DC current is converted into an AC rectangular wave current (light source driving power) by the inverter circuit 23. The igniter circuit 24 performs dielectric breakdown between the electrodes of the discharge lamp 30 and prompts the discharge lamp 30 to start.

  On the other hand, the voltage detection circuit 25 in the ballast control unit measures the DC voltage stepped down by the down converter 22 based on the instruction signal from the ballast control circuit 28 that has received an instruction from the main board side. This DC voltage is set as a lamp voltage. The measured lamp voltage is converted from an analog value to a digital value by the A / D converter 26. The communication circuit 27 transmits the lamp voltage that has become a digital value to the main board side via the ballast-main board interface 70. Further, the communication circuit 27 receives a lamp voltage detection instruction signal from the main board side and transmits it to the ballast control circuit 28.

  FIG. 3 is a functional block diagram showing the functional configuration of the projector. A functional configuration of the projector 100 will be described with reference to FIG.

  The projector 100 includes a power supply unit 10, a ballast 20, a discharge lamp 30, a video input unit 110, a video signal processing unit 111, an OSD processing unit 112, a video projection unit 113, a video control unit 114, and an operation. Reception unit 115, control unit 116, lamp control unit 117, time measurement unit 118, lamp voltage detection unit 119, lamp voltage storage unit 120, function generation unit 121, function storage unit 122, and lamp voltage An upper limit storage unit 123, a remaining time calculation unit 124, a lamp voltage comparison unit 125, and a remaining time comparison unit 126 are provided. Here, a functional unit that combines the video control unit 114, the video signal processing unit 111, and the OSD processing unit 112 is referred to as a video control processing unit 80 in FIG.

Next, the operation of the projector 100 will be described using the functional configuration.
The power supply unit 10 is connected to a power cable (not shown) and supplies power to the projector 100. The ballast 20 is supplied with power from the power supply unit 10 and generates electric power for driving the discharge lamp 30. The ballast 20 turns on the discharge lamp 30 according to an instruction from the lamp control unit 117. The ballast 20 outputs the lamp voltage measured by the built-in voltage detection circuit 25 (see FIG. 2) to the lamp voltage detection unit 119.

  The video input unit 110 inputs a video signal from the external video output device 300 (see FIG. 1). The input video signal is processed by the video signal processing unit 111 as necessary. Video processing indicates, for example, image processing such as enlargement or reduction, trapezoid correction processing, and the like. Next, the OSD processing unit 112 superimposes the OSD display on the video that has been subjected to video processing, as necessary. The video projection unit 113 projects the video signal output from the OSD processing unit 112 as a video. The video control unit 114 performs instruction control related to video processing for the video signal processing unit 111, the OSD processing unit 112, and the video projection unit 113 in accordance with an instruction from the control unit 116.

  The operation accepting unit 115 receives a function operation instruction to the projector 100 by a user using an operation unit such as a key switch (not shown) constituting the projector 100 or a remote control light receiving unit (not shown) constituting the projector 100 receives light. A function operation instruction to the projector 100 by the user using a remote controller provided separately from the computer 100 is received. The control unit 116 performs overall control of the projector 100 in order to perform a functional operation corresponding to the functional operation instruction received by the operation receiving unit 115. Other control contents performed by the control unit 116 include, for example, an instruction related to video signal processing to the video control unit 114, a time measurement instruction to the time measurement unit 118, and lighting / discharging of the discharge lamp 30 to the lamp control unit 117. An instruction to turn off, control of a cooling fan (not shown), and the like are performed.

  The lamp control unit 117 performs lighting control of the discharge lamp 30 using the ballast 20 according to an instruction from the control unit 116. The time measuring unit 118 measures the usage time (accumulated lighting time) of the discharge lamp 30 according to an instruction from the control unit 116. Further, the time measuring unit 118 performs periodic time measurement for detecting the lamp voltage, and instructs the lamp voltage detecting unit 119 to detect the lamp voltage. In response to an instruction from the time measurement unit 118, the lamp voltage detection unit 119 transmits a lamp voltage detection instruction signal of the discharge lamp 30 to the ballast 20, and receives the lamp voltage as a detection result. The lamp voltage storage unit 120 receives the lamp voltage from the lamp voltage detection unit 119 and stores it in the lamp information memory 31 (see FIG. 1). Further, the lamp voltage storage unit 120 receives the usage time when the lamp voltage is detected from the time measurement unit 118 and stores it in the lamp information memory 31 together with the lamp voltage.

  The function generation unit 121 uses the lamp voltage and usage time stored in the lamp voltage storage unit 120 to generate a lamp voltage function. A method for generating the lamp voltage function will be described later. The function storage unit 122 stores the lamp voltage function generated by the function generation unit 121 in the RAM 50 (see FIG. 1) or the lamp information memory 31 as a function. The lamp voltage upper limit storage unit 123 stores a lamp voltage upper limit value, which is an upper limit lamp voltage at which the discharge lamp 30 used in the projector 100 can operate, in the ROM 60 (see FIG. 1). Here, the lamp voltage upper limit value is a voltage value determined by the specifications of the discharge lamp 30 to be used.

  The remaining time calculation unit 124 calculates the remaining time that the discharge lamp 30 can be used in accordance with an instruction from the control unit 116. Here, a method for calculating the remaining time is shown below. The remaining time calculation unit 124 uses the lamp voltage upper limit value stored in the lamp voltage upper limit value storage unit 123 and the lamp voltage function stored in the function storage unit 122 so that the lamp voltage function reaches the lamp voltage upper limit value. Time is calculated and set as the first time. This calculated first time is the life time of the discharge lamp 30. Further, the remaining time calculation unit 124 uses the current usage time of the discharge lamp 30 measured by the time measurement unit 118 and calculates a difference from the first time. Then, the remaining time calculation unit 124 notifies the control unit 116 of the calculated difference value as the remaining time. The remaining time indicates the remaining time until the life of the discharge lamp 30.

  The lamp voltage comparison unit 125 compares the lamp voltage detected by the lamp voltage detection unit 119 with the lamp voltage upper limit value stored in the lamp voltage upper limit value storage unit 123, and the lamp voltage is equal to or higher than the lamp voltage upper limit value. Whether or not to notify the control unit 116. Further, the lamp voltage comparison unit 125 compares the lamp voltage with a value obtained by subtracting a predetermined voltage from the lamp voltage upper limit value, and determines whether or not the lamp voltage is equal to or greater than a value obtained by subtracting the predetermined voltage from the lamp voltage upper limit value. , Notify the control unit 116.

  Further, the remaining time comparison unit 126 compares the remaining time calculated by the remaining time calculation unit 124 with a predetermined first remaining time, which will be described later, and determines whether or not the remaining time is equal to or less than the predetermined first remaining time. The function storage unit 122 is notified. Furthermore, the remaining time comparison unit 126 compares the remaining time with a predetermined second remaining time, which will be described later, determines whether the remaining time is equal to or less than the predetermined second remaining time, and notifies the control unit 116 of it. Furthermore, the remaining time comparison unit 126 compares the remaining time with 0 hour, determines whether or not the remaining time is 0 hour or less, and notifies the control unit 116 of it.

  With the configuration described above, the projector 100 can calculate the remaining usable time of the discharge lamp 30 while projecting an image using the discharge lamp 30 as a light source.

  Next, the remaining time calculation processing of the projector 100 in the present embodiment will be described using a flowchart.

  FIG. 4 is a flowchart of the remaining time calculation process of the projector according to the embodiment. The projector 100 detects the lamp voltage at every predetermined usage time interval, generates a lamp voltage function using the result, and calculates the remaining time. In the present embodiment, the predetermined use time interval is 50 hours, and the flowchart of FIG. 4 represents a remaining time calculation process performed every 50 time intervals. Here, as described above, the usage time is a cumulative time during which the discharge lamp 30 is lit. With reference to FIG. 4, the remaining time calculation processing of the projector 100 performed every 50 hours will be described.

  The lamp voltage detector 119 transmits a lamp voltage detection instruction signal for the discharge lamp 30 to the ballast 20 and receives the lamp voltage detected by the ballast 20 (step S100). Next, the lamp voltage storage unit 120 stores the detected lamp voltage and the usage time when the lamp voltage is detected in the lamp information memory 31 (step S101).

  Here, as shown in FIG. 6, the lamp information memory 31 stores the usage time and the lamp voltage as data. FIG. 6 is a diagram showing a data array in the lamp information memory. As shown in the array H1, the lamp voltage function is stored in the head address of the lamp information memory 31. However, since the lamp voltage function is written when a condition described later is satisfied, “0” is stored as an initial value. From the next address of the lamp voltage function, the usage time every 50 hours and the lamp voltage detected at that time are stored. 6 shows the data array of the usage time from 0 (H: time) to 300 (H) and the lamp voltage (V: volt) at that time, the data after 300 (H) is also sequentially. It shall be remembered.

  Returning to FIG. 4, next, the function generation unit 121 determines whether or not the lamp voltage function is stored in the lamp information memory 31 (step S102). When “0” is stored in the head address of the lamp information memory 31, the function generation unit 121 determines that the lamp voltage function is not stored (step S102: NO). When the lamp voltage function is not stored, the function generation unit 121 generates a lamp voltage function using all the usage time and lamp voltage data stored in the lamp information memory 31 (step S103).

In this embodiment, the exponential approximation of the least square method is used as a method of generating the lamp voltage function. Thereby, the rise change with the use time of a lamp voltage can be approximated to an exponential curve. The exponential approximate lamp voltage function is expressed by the following formula (1) as a general formula.
y = a * e ^bx (1)
Note that x is a usage time (H: hour), y is a lamp voltage (V: volt), e is a Napier number, and a and b are coefficients.

  Here, FIG. 7 is a graph of a lamp voltage function generated using exponential approximation of the least square method. In the graph of FIG. 7, the x-axis indicates the usage time, and the y-axis indicates the lamp voltage. The points plotted on the graph indicate the usage time and lamp voltage data of the array H1 shown in FIG. The function F1 is a lamp voltage function generated by using the least square method exponential approximation of the data of the above plotted points. The function F1 is stored in the RAM 50 by the function storage unit 122.

  Returning to FIG. 4, next, the remaining time calculating unit 124 calculates the remaining usable time of the discharge lamp 30 using the lamp voltage function and the current used time (step S104). Specifically, the remaining time calculation unit 124 calculates the time for the lamp voltage function to reach the lamp voltage upper limit value using the lamp voltage upper limit value and the lamp voltage function stored in the lamp voltage upper limit value storage unit 123. And the first time. This calculated first time is the life time of the discharge lamp 30. In this embodiment, the lamp voltage upper limit value is 130V. Furthermore, the remaining time calculation unit 124 calculates the difference between the current usage time and the first time, and uses the calculated difference value as the remaining time. The remaining time indicates the remaining time until the life of the discharge lamp 30.

  Here, the calculation of the remaining time will be described with reference to FIG. FIG. 8 is a graph showing the relationship between the lamp voltage function and the usage time. In the graph of FIG. 8, the x-axis indicates the usage time, and the y-axis indicates the lamp voltage. On the x-axis, the first time T1 and the current usage time T2 are shown. On the y-axis, the lamp voltage upper limit value V0 is shown. A function F1 shows a lamp voltage function similar to that in FIG. As shown in the graph of FIG. 8, the first time T1 is determined from the function F1 and the lamp voltage upper limit value V0. Furthermore, the remaining time t can be calculated from the first time T1 and the current usage time T2. Here, the calculation method of the first time T1 and the calculation method of the remaining time t will be described by replacing the function F1 with the general formula (1).

When the first time T1 and the lamp voltage upper limit value V0 are applied to the equation (1), the following equation (2) is obtained.
V0 = a * e ^bT1 (2)
Here, by calculating and organizing the natural logarithm of both sides of the formula (2), the first time T1 is expressed by the following formula (3).
T1 = (logV0−loga) / b (3)
Next, the remaining time t can be calculated by subtracting the current usage time T2 from the first time T1. That is, the remaining time t is expressed by the following formula (4).
t = T1-T2 (4)

  Returning to FIG. 4, next, the remaining time comparison unit 126 determines whether or not the remaining time is equal to or less than a predetermined first remaining time (step S105). The predetermined first remaining time is a time at which the fluctuation of the lamp voltage function generated by the function generation unit 121 is reduced and is assumed to be substantially fixed. In the present embodiment, the predetermined first remaining time is 300 hours, but is not limited to 300 hours. When it is determined that the remaining time is not equal to or less than the predetermined first remaining time (step S105: NO), the remaining time calculation process shown in the flowchart ends. When it is determined that the remaining time is equal to or less than the predetermined first remaining time (step S105: YES), the function storage unit 122 stores the lamp voltage function stored in the RAM 50 in the lamp information memory 31 (step S106). . That is, the lamp voltage function is written in the address (start address) of the lamp voltage function in the array H1 in FIG. And the remaining time calculation process which this flowchart shows is complete | finished.

  On the other hand, the case where the lamp voltage function is stored in the lamp information memory 31 in step S102 (step S102: YES) will be described. Here, in step S107 and step S108, the detected lamp voltage is compared with the lamp voltage upper limit value or a value obtained by subtracting a predetermined voltage from the lamp voltage upper limit value by the voltage value. This is because when the lamp voltage has increased unexpectedly (when the detected lamp voltage deviates significantly from the lamp voltage function), the discharge lamp 30 has deviated from the voltage within the rated specification range, or out of the rated specification range. This is to detect that the voltage is close to the state of the voltage.

  The lamp voltage comparison unit 125 determines whether or not the lamp voltage detected this time is equal to or higher than the lamp voltage upper limit value (step S107). When the lamp voltage is equal to or higher than the lamp voltage upper limit value (step S107: YES), the lamp control unit 117 turns off the discharge lamp 30 (step S112). Specifically, the lamp voltage comparison unit 125 notifies the control unit 116 that the discharge lamp 30 is in a voltage state outside the rated specification range, and the control unit 116 notifies the lamp control unit 117 of the discharge lamp. 30 is instructed to be turned off. And the remaining time calculation process which this flowchart shows is complete | finished.

  When the lamp voltage is not equal to or higher than the lamp voltage upper limit value (step S107: NO), the lamp voltage comparison unit 125 determines whether or not the lamp voltage is equal to or higher than a value obtained by subtracting a predetermined voltage from the lamp voltage upper limit value. (Step S108). Here, a value obtained by subtracting a predetermined voltage from the lamp voltage upper limit value is a voltage that requires replacement of the discharge lamp 30 determined from the specifications of the discharge lamp 30. In the present embodiment, the predetermined voltage is 5 V (volts), but is not limited to 5 V. If the value is equal to or greater than the value obtained by subtracting 5 V from the lamp voltage upper limit value (step S108: YES), the video control unit 114 displays a message prompting lamp replacement on the second display unit (step S113). In the present embodiment, the second display unit is an OSD display that is superimposed on the image projected by the projector 100. As a specific operation, the lamp voltage comparison unit 125 notifies the control unit 116 that the discharge lamp 30 is close to a voltage outside the rated specification range, and the control unit 116 notifies the video control unit 114 of the lamp. Instructs to display a message prompting the exchange. The video control unit 114 instructs the OSD processing unit 112 to OSD display a message prompting lamp replacement. And the remaining time calculation process which this flowchart shows is complete | finished.

  Next, when the lamp voltage is not equal to or higher than the value obtained by subtracting 5 V from the lamp voltage upper limit value (step S108: NO), the remaining time calculation unit 124 uses the lamp voltage function and the current usage time to calculate the discharge lamp 30. A usable remaining time is calculated (step S109). The lamp voltage function used here uses the lamp voltage function stored in the lamp information memory 31. The remaining time calculation process is the same as step S104.

  Next, the remaining time comparison unit 126 determines whether or not the remaining time calculated by the remaining time calculation unit 124 is 0 hour or less (step S110). When the remaining time is 0 hour or less (step S110: YES), the lamp control unit 117 turns off the discharge lamp 30 (step S112). And the remaining time calculation process which this flowchart shows is complete | finished.

  When the remaining time is not 0 hours or less (step S110: NO), the remaining time comparison unit 126 determines whether or not the remaining time is equal to or less than a predetermined second remaining time (step S111). The predetermined second remaining time is a time that requires replacement of the discharge lamp determined from the specification of the discharge lamp. In the present embodiment, the predetermined second remaining time is 100 hours, but is not limited to 100 hours. When the remaining time is equal to or less than the predetermined second remaining time (step S111: YES), the video control unit 114 displays a message for urging lamp replacement on the second display unit (step S113). And the remaining time calculation process which this flowchart shows is complete | finished. If the remaining time is not less than or equal to the predetermined second remaining time (step S111: NO), the remaining time calculation process shown in the flowchart ends.

  Next, the remaining time display process of the projector in the present embodiment will be described using a flowchart.

  FIG. 5 is a flowchart of the remaining time display process of the projector according to the present embodiment. The remaining time display process is a process executed when an operation for displaying the remaining time is performed by the user. In this embodiment, an item “display remaining time until lamp life” is provided in the function menu implemented as software in projector 100, and the user operates the operation unit such as a remote control or key switch to instruct projector 100 to perform the remaining operation. It is designed to display time. The remaining time display process of the projector 100 will be described with reference to FIG.

  The function generator 121 determines whether or not a lamp voltage function is stored in the lamp information memory 31 (step S200). When “0” is stored in the address of the lamp voltage function, the function generation unit 121 determines that the lamp voltage function is not stored (step S200: NO). When the lamp voltage function is not stored, the function generation unit 121 generates a lamp voltage function using all the usage time and lamp voltage data stored in the lamp information memory 31 (step S201). The processing content of the lamp voltage function generation is the same as step S103 in the flowchart of FIG.

  On the other hand, when the lamp voltage function is stored in the lamp information memory 31 in step S200 (step S200: YES), the lamp voltage function stored in the lamp information memory 31 is used in the subsequent processing. The process proceeds to step S202.

  Next, the remaining time calculating unit 124 calculates the remaining usable time of the discharge lamp 30 using the lamp voltage function and the current usage time (step S202). The processing content of the remaining time calculation is the same as step S104 in the flowchart of FIG.

  Next, the video control unit 114 displays the remaining time on the first display unit (step S203). In the present embodiment, the first display unit is an OSD display that is superimposed on the image projected by the projector 100. That is, the remaining time is superimposed as an OSD display by the OSD processing unit 112 on the image projected by the projector 100. The time for displaying the remaining time is set to several seconds so that the user can afford to recognize it.

  Next, the remaining time comparison unit 126 determines whether or not the remaining time calculated by the remaining time calculation unit 124 is 0 hour or less (step S204). When the remaining time is 0 hour or less (step S204: YES), the lamp control unit 117 turns off the discharge lamp 30 (step S206). Specific processing and operation are the same as those in step S112 in FIG. And the remaining time display process which this flowchart shows is complete | finished.

  When the remaining time is not 0 hours or less (step S204: NO), the remaining time comparison unit 126 determines whether or not the remaining time is equal to or less than a predetermined second remaining time (step S205). As described above, in the present embodiment, the predetermined second remaining time is 100 hours. When the remaining time is equal to or less than the predetermined second remaining time (step S205: YES), the video control unit 114 displays a message for urging lamp replacement on the second display unit (step S207). Specific processing and operation are the same as those in step S113 in FIG. And the remaining time display process which this flowchart shows is complete | finished. If the remaining time is not less than or equal to the predetermined second remaining time (step S205: NO), the remaining time display process shown in the flowchart ends.

According to the embodiment described above, the following effects can be obtained.
(1) The projector 100 detects the lamp voltage, generates a lamp voltage function, and calculates the remaining time from the current use time to the life of the discharge lamp 30 using the lamp voltage function. Therefore, the remaining time can be calculated more accurately than the conventional method in which the lamp life time is fixedly determined in advance and the remaining time is calculated from the difference from the usage time.

  (2) Further, the projector 100 uses the least square method when generating the lamp voltage function. Thereby, the lamp voltage function can be approximated with high accuracy from the lamp voltage and the usage time. Further, the least square method is a generally known approximation method and is preferable because it can be easily realized by software or the like. Therefore, the projector 100 can calculate an accurate remaining time from the lamp voltage function approximated with high accuracy.

  (3) Further, the projector 100 detects the lamp voltage at every predetermined usage time interval, stores the lamp voltage and the usage time at the time of detection, and generates a lamp voltage function. Thus, the projector 100 can generate a lamp voltage function that follows the change in the lamp voltage of the discharge lamp 30 being used. That is, a lamp voltage function that always reflects the detected lamp voltage can be generated. Therefore, the projector 100 can calculate an accurate remaining time from the lamp voltage function that follows the change in the lamp voltage.

  (4) In addition, when the remaining time becomes equal to or less than the predetermined first remaining time, the projector 100 stops generating the lamp voltage function for each predetermined usage time interval. Thereafter, the remaining time is calculated using the last generated lamp voltage function. The predetermined first remaining time is a time when the change in the lamp voltage function generated by the projector 100 is expected to converge. Thereby, after it becomes below predetermined 1st remaining time, the process which produces | generates a lamp voltage function can be abbreviate | omitted, and the load of software processing can be reduced. Therefore, an improvement in operation responsiveness as the projector 100 can be expected.

  (5) Further, the projector 100 can make the user recognize the calculated remaining time. Therefore, the user can grasp the time until the life of the discharge lamp 30. Furthermore, the user can know the remaining time to replace the discharge lamp 30 and prepare for replacement. Thereby, for example, it is possible to avoid that the lamp life is reached while the user is giving a presentation using the projector 100 and the discharge lamp 30 is not turned off.

  (6) In addition, when the projector 100 determines that the remaining time is equal to or less than a predetermined second remaining time that is a time for which the discharge lamp 30 needs to be replaced, the projector 100 displays a message prompting the user to replace the lamp. Can be recognized. Therefore, the user can replace the discharge lamp 30 before the discharge lamp 30 reaches the end of its life.

  (7) In addition, the projector 100 can turn off the discharge lamp 30 when it is determined that the remaining time has become 0 hours or less indicating that the life of the discharge lamp 30 has been reached. Therefore, it can be avoided that the discharge lamp 30 continues to be used in a state of being out of the rated specification voltage range. Therefore, safety in using the discharge lamp 30 can be maintained.

  (8) Since the projector 100 stores the lamp voltage, the usage time, and the lamp voltage function information in the lamp information memory 31 provided in the lamp unit, the replaced lamp is replaced even if the lamp unit is replaced. The remaining time corresponding to the discharge lamp 30 of the unit can be calculated. Therefore, the user can replace the discharge lamp 30 of the same specification with a lamp unit of the discharge lamp 30 which is new or used. Then, the remaining time corresponding to the discharge lamp 30 can be known. Further, a message prompting lamp replacement can be displayed corresponding to the discharge lamp 30, and the discharge lamp 30 can be turned off when the discharge lamp 30 reaches the end of its life.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, it can implement with a various form in the range which does not deviate from the summary of this invention. A modification is described below.

  (Modification 1) In the above embodiment, the display device is the projector 100, but it may be a rear projection television. In addition, the present invention can be implemented as long as the display device includes a discharge lamp as a light source.

  (Modification 2) In the above embodiment, the first display unit and the second display unit are superimposed on the projected image as the OSD display, but the first display unit and the second display unit are A display unit such as a liquid crystal display provided on the housing of the projector 100 may be used. By doing this, the user can check the remaining time by visually recognizing the liquid crystal display without the OSD display blocking the projected image. Further, the first display unit and the second display unit may be LEDs (Light Emitting Diode). In this way, the remaining time can be expressed by turning on / off / flashing the LED and controlling the color, and it is also possible to express a message prompting lamp replacement. For example, if the remaining time is greater than 500 hours / greater than 300 hours but less than 500 hours / more than 100 hours but less than 300 hours / encourage lamp replacement in less than 100 hours, the LED is divided into It can be expressed using. This makes it possible to reduce the software processing load.

  (Modification 3) Further, in the above embodiment, the display of the remaining time is expressed by a number, but a display intended for the remaining time may be performed. For example, the usage time and the remaining time may be represented by a graphic such as a bar graph. In this way, the user can recognize the current usage time and remaining time graphically.

  (Modification 4) In the above-described embodiment, the time interval for performing the remaining time calculation process is set as the predetermined use time interval, which is 50 hours, but may be shorter. For example, it may be 1 hour interval or 10 minute interval. In this way, when there is a sudden change in the lamp voltage, the reflection to the lamp voltage function is performed in a short time, and the accuracy of calculation of the remaining time is improved. Also, when the discharge lamp 30 is near the end of life or when the discharge lamp 30 has reached the end of its life, the detection interval is short, so that a message prompting lamp replacement or the discharge lamp 30 can be turned off early. it can.

  (Modification 5) In the above embodiment, the time interval for performing the remaining time calculation process is a predetermined use time interval. However, when the projector 100 is turned on, the discharge lamp 30 is turned on, and the lamp voltage of the discharge lamp 30 is The remaining time calculation process may be performed even at a stable time. The time from when the discharge lamp 30 is turned on until the lamp voltage is stabilized is about 5 minutes. In this way, since the remaining time of the discharge lamp 30 can be calculated in a short time (about 5 minutes) after the projector 100 is turned on, when the life of the discharge lamp 30 is near or when the discharge lamp 30 has reached the end of its life. With regard to the above, it is possible to promptly display a message for urging lamp replacement and turn off the discharge lamp 30 from the time when the projector 100 is turned on.

  (Modification 6) In the above embodiment, the remaining time display process is performed by an instruction from the user. However, the remaining time display process is performed even when the projector 100 is turned on and the discharge lamp 30 is turned on. It is good. In this way, the user can recognize the remaining usable time of the discharge lamp 30 immediately after the projector 100 is turned on. That is, even if the user does not give an instruction to check the remaining time, the remaining time can be automatically displayed immediately after the projector 100 is turned on, and can be recognized by the user.

  (Modification 7) In the above embodiment, the lamp voltage upper limit value is stored in the ROM 60, but may be stored in the lamp information memory 31. In this way, when a discharge lamp having a different specification for the lamp voltage upper limit value is used, the lamp information memory 31 is replaced by replacing the lamp unit, and the lamp voltage upper limit value and the lamp voltage in the lamp information memory 31 are replaced. Function, usage time and lamp voltage data are also exchanged. Therefore, the value for the first time determined by the lamp voltage function and the lamp voltage upper limit value is changed, and the remaining time corresponding to the discharge lamp having different specifications can be calculated.

  (Modification 8) In the above embodiment, the generation of the lamp voltage function is performed by using all the usage time and lamp voltage data stored in the lamp information memory 31, but the generation of the lamp voltage function is performed. The data used for can be selected. For example, the lamp voltage function can be generated using the most recent 20 usage times and lamp voltage data. In this case, when it is inappropriate to use the initial data of the discharge lamp 30 for generating the lamp voltage function due to the lamp voltage characteristic of the discharge lamp 30 (for example, the change characteristic of the lamp voltage is the time In this case, an effective lamp voltage function can be generated using only the latest data. Further, if the number of data to be used is reduced, the load of the software processing of the approximation processing by the least square method is reduced, so that it is expected that the operation responsiveness as the projector 100 is improved.

  (Modification 9) In the above embodiment, the remaining time calculation process of the discharge lamp 30 is performed on the main board, but the remaining time calculation process may be performed in the ballast 20. For example, the remaining time calculated in the ballast 20 can be replaced with 2-bit information, and the projector 100 can express the 2-bit information with two LEDs. For example, it can be expressed as follows. If the state of the two LEDs is (off, off), the remaining time is greater than 300 hours. If (lit, off), the remaining time is greater than 100 hours and less than 300 hours. Then, the remaining time is 100 hours or less. By doing so, software processing such as remaining time calculation processing and OSD display processing on the main board side is reduced, and improvement in operation responsiveness as the projector 100 can be expected.

  (Modification 10) In the above embodiment, the approximation method for generating the ramp voltage function is the exponential approximation of the least square method, but other approximation methods include logarithmic approximation, polynomial approximation, and power approximation of the least square method. It is good also as what can select etc. In this way, the most suitable approximation can be performed according to the characteristics of the discharge lamp 30 to be used, and an optimal lamp voltage function can be generated in calculating the remaining time. The approximation method may be selected by providing a “menu for selecting a data approximation method when generating a lamp voltage function” item in the function menu implemented as software in the projector 100 and allowing the user to select the item, or for the discharge lamp 30 to be used. An optimum approximation method may be incorporated in the program in advance.

  (Modification 11) In the above embodiment, the lamp voltage function is generated while detecting the lamp voltage, but the lamp voltage function may be stored in advance. For example, a lamp voltage function corresponding to the characteristics of the discharge lamp 30 to be used can be stored in the lamp information memory 31. In this way, it is possible to calculate an appropriate remaining time corresponding to the lamp voltage characteristics of the discharge lamp 30. Furthermore, since the process of generating the lamp voltage function while detecting the lamp voltage is not required, the software process is reduced and the operation responsiveness as the projector 100 can be expected to be improved.

FIG. 2 is a circuit block diagram showing an internal configuration of the projector according to the embodiment. The circuit block diagram which shows the ballast internal structure of a projector. The functional block diagram which shows the function structure of a projector. The flowchart of the remaining time calculation process of a projector. The flowchart of the remaining time display process of a projector. The figure showing the data arrangement in a lamp information memory. The graph of the lamp voltage function produced | generated using the exponential approximation of the least square method. The graph showing the relationship between a lamp voltage function and use time.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Power supply part, 20 ... Ballast, 21 ... EMI filter, 22 ... Down converter, 23 ... Inverter circuit, 24 ... Igniter circuit, 25 ... Voltage detection circuit, 26 ... A / D converter, 27 ... Communication circuit, 28 ... Ballast Control circuit, 30 ... discharge lamp, 31 ... lamp information memory, 40 ... CPU, 50 ... RAM, 60 ... ROM, 70 ... ballast-main board interface, 80 ... video control processing unit, 100 ... projector, 110 ... video input 111: Video signal processing unit, 112 ... OSD processing unit, 113 ... Video projection unit, 114 ... Video control unit, 115 ... Operation receiving unit, 116 ... Control unit, 117 ... Lamp control unit, 118 ... Time measuring unit, 119: Lamp voltage detection unit, 120 ... Lamp voltage storage unit, 121 ... Function generation unit, 122 ... Function storage unit, 123 ... Run Voltage upper limit value storage unit, 124 ... remaining time calculation unit, 125 ... lamp voltage comparator, 126 ... remaining time comparison unit 200 ... screen, 300 ... external video output device.

Claims (8)

A display device comprising a discharge lamp,
A time measuring unit for measuring the usage time from the start of use of the discharge lamp;
A lamp voltage upper limit storage unit for storing a lamp voltage upper limit value which is an upper limit lamp voltage at which the discharge lamp can operate;
A function storage unit that stores a lamp voltage function that predicts a change of the lamp voltage with the passage of time of use;
Remaining time for calculating the difference between the first time derived from the lamp voltage upper limit value and the lamp voltage function and the usage time measured by the time measurement unit as the remaining usable time of the discharge lamp A calculation unit;
A display device comprising: The display device according to claim 1,
The display device further includes a lamp voltage detection unit that detects the lamp voltage when the discharge lamp is driven,
A lamp voltage storage unit that stores the lamp voltage detected by the lamp voltage detection unit and the usage time at the time of detection;
A function generator for generating the lamp voltage function based on the lamp voltage and the usage time stored in the lamp voltage storage;
A display device comprising: The display device according to claim 2,
The lamp voltage detection unit detects the lamp voltage every predetermined use time interval,
The lamp voltage storage unit stores the lamp voltage and the usage time at the time of detection for each predetermined usage time interval,
The display device characterized in that the function generating unit generates the lamp voltage function based on the lamp voltage and the usage time stored in the lamp voltage storage unit at each predetermined usage time interval. The display device according to claim 3,
The display device according to claim 1, wherein the function generation unit stops generating the ramp voltage function when the remaining time calculated by the remaining time calculation unit is equal to or less than a predetermined first remaining time. The display device according to any one of claims 1 to 4,
The display device includes a first display unit that displays the remaining time calculated by the remaining time calculation unit. A display device according to any one of claims 1 to 5,
The display device includes a second display unit that performs a display to prompt replacement of the discharge lamp in use when the remaining time calculated by the remaining time calculation unit is equal to or less than a predetermined second remaining time. A display device comprising: The display device according to any one of claims 1 to 6,
The display device turns off the discharge lamp when the remaining time calculated by the remaining time calculation unit is 0 or less. A display device according to any one of claims 2 to 7,
The discharge lamp is configured as a lamp unit,
The lamp unit includes a lamp information memory,
The lamp information memory includes the lamp voltage storage unit and the function storage unit.

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