JP2011086379A - Cold-cathode tube lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold-cathode tube lighting device capable of recording failure information when a failure occurs at the time of lighting a cold-cathode tube. <P>SOLUTION: In the cold-cathode tube lighting device 50, if a failure occurs at the time of lighting a cold-cathode tube 12, such failure information is recorded. Then, such failure information is checked on later days and a point of a cause of the occurred failure can be specified to some extent. Further, if the cold-cathode tube 12 is degraded, a degree of degradation of the cold-cathode tube 12 can be grasped from the failure information to some extent. Therefore, an exchange or an estimated timing for exchanging a cold-cathode tube unit can be given to a user. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cold-cathode tube lighting device mainly used for a liquid crystal panel of an on-vehicle electric apparatus, and more particularly to a cold-cathode tube lighting device that records failure information when a failure occurs when the cold-cathode tube is turned on. is there.

  In recent years, in-vehicle electric devices equipped with a liquid crystal display device such as a car navigation system, an in-vehicle television, and an in-vehicle DVD player have been widely spread. The liquid crystal used in these liquid crystal display devices does not emit light per se and requires a separate light source. As this light source, a cold cathode tube (CCFL tube: Cold Cathode Fluorescent Lamp), which is a small fluorescent tube, is often used particularly when space saving is required as in an in-vehicle electric device.

  Here, in the following [Patent Document 1], an invention relating to a lighting device including a voltage abnormality detection circuit applicable to a cold cathode tube is disclosed.

JP 2009-64568 A

  However, the invention disclosed in [Patent Document 1] is a protection circuit that stops the output to the cold cathode tube when a voltage abnormality occurs. If a failure occurs in the lighting of the cold cathode tube, the failure will be confirmed later. I can't do it.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a cold-cathode tube lighting device capable of recording failure information when a failure occurs when the cold-cathode tube is turned on.

The present invention
(1) A lighting unit 20 that lights a cold cathode tube 12 as a light source of the liquid crystal display 10, and a control unit 22 that outputs an activation signal for lighting the cold cathode tube 12 to the lighting unit 20. In the cold-cathode tube lighting device 50 having
A clock unit 24 that acquires date and time information, a timer unit 26 that measures an elapsed time since the start signal is output, and an output voltage to the cold cathode tube 12 when the elapsed time reaches a predetermined value And a non-lamp information and date / time information in response to the output of the non-lamp information, and a non-lamp information output when the output voltage value is outside a predetermined determination range. The above problem is solved by providing a cold-cathode tube lighting device 50 including a failure information generation unit 30 that generates failure information and a recording unit 32 that records the failure information.

  According to the cold-cathode tube lighting device according to the present invention, when a failure occurs during lighting of the cold-cathode tube, failure information including information at the time of the failure is recorded. By confirming the failure information, the degree of deterioration of the cold cathode tube and the location where the failure occurs can be specified to some extent.

It is a block diagram which shows the cold cathode tube lighting device which concerns on this invention. It is a timing chart explaining operation | movement of the cold cathode tube lighting device which concerns on this invention. It is a timing chart explaining operation | movement of the cold cathode tube lighting device which concerns on this invention.

  An embodiment of a cold cathode tube lighting device according to the present invention will be described with reference to the drawings. A cold-cathode tube lighting device 50 according to the present invention shown in FIG. 1 includes a lighting unit 20 that lights a cold-cathode tube 12 as a light source of the liquid crystal display 10, and a lighting unit that emits a start signal for lighting the cold-cathode tube 12. 20, a clock unit 24 that acquires current date and time information, a timer unit 26 that measures an elapsed time since the start signal is output, and a predetermined time after the start signal is output. A monitoring unit 28 that acquires the value of the output voltage to the cold cathode tube 12 when time elapses and outputs non-lamp information when the acquired output voltage value is outside a predetermined determination range; It has a failure information generation unit 30 that receives the output of the non-lamp information and creates fault information including at least the non-lamp information and the date and time information from the clock unit 24, and a recording unit 32 that records the fault information. . In FIG. 1, the timer unit 26, the monitoring unit 28, and the failure information generation unit 30 are described separately from the control unit 22, but these blocks may be provided in the control unit 22.

  The liquid crystal display 10 can use a known transmissive liquid crystal or reflective liquid crystal. However, it is preferable to use a transmissive liquid crystal in an in-vehicle electric device that is required to be downsized. In this case, the cold cathode tube 12 as a light source serves as a backlight.

  The clock unit 24 includes the date and time on the vehicle-mounted electrical device side when the vehicle-mounted electrical device on which the cold-cathode tube lighting device 50 is mounted has, for example, a car navigation system or a terrestrial digital TV. The information acquisition means can be the clock unit 24. Further, when the vehicle-mounted electrical device side does not include date / time information acquisition means, the clock unit 24 has a timekeeping function, for example, and sets the date and time when the vehicle-mounted electrical device is initially set.

  As the recording unit 32, a known non-volatile semiconductor memory such as an EEPROM, a flash memory, or a semiconductor memory card can be used.

  Next, the configuration and operation of each part of the cold cathode tube lighting device 50 according to the present invention will be described. First, a user inserts a car key into a key switch and turns it on. When the key switch is turned on, electric power is supplied from the vehicle battery to the in-vehicle electric device having the cold cathode tube lighting device 50. When power is supplied to the in-vehicle electrical device, the power source of the in-vehicle electrical device is usually automatically turned on. When the power source of the on-vehicle electric device is turned on, the control unit 22 of the cold cathode tube lighting device 50 outputs a start signal to the lighting unit 20. In addition, the timer unit 26 receives an activation signal from the control unit 22 and starts counting elapsed time from when the activation signal is output. The lighting unit 20 is a known inverter circuit using, for example, a resonant transformer for the cold cathode tube 12, receives an activation signal from the control unit 22, converts electric power supplied from the vehicle battery into a predetermined high-frequency voltage, and cools it. Output to the cathode tube 12. The output voltage value until the cold cathode tube 12 is lit is about 1400V. Here, when the cold cathode tube 12 is not defective or deteriorated, the cold cathode tube 12 is lit within about 100 msec. When the cold cathode tube 12 is turned on, the cold cathode tube 12 becomes a load and a tube current flows down. As a result, the output voltage value of the lighting unit 20 decreases to about 600 V as shown in FIG.

  Note that if the cold cathode tube 12 does not light even when power is output for a certain start-up period (about 1 sec) (when the output voltage value does not decrease), the lighting unit 20 temporarily stops output to the cold cathode tube 12. To do. When the control unit 22 detects the stop of the output to the cold cathode tube 12, the control unit 22 stops the start signal, and outputs the start signal to the lighting unit 20 again as a re-lighting operation after a predetermined time has elapsed. At this time, the timer unit 26 resets the previous elapsed time and newly starts counting the elapsed time. If the cold-cathode tube 12 is not lit even when the activation signal is output by the re-lighting operation, the output to the cold-cathode tube 12 is stopped and then the re-lighting operation is repeated a predetermined number of times. If the cold-cathode tube 12 does not light even after repeating the re-lighting operation a predetermined number of times, the control unit 22 stops the lighting operation to the cold-cathode tube 12 on the assumption that there is some malfunction in the cold-cathode tube 12 or the lighting unit 20 To do. At this time, the failure may be notified to the user, or the function of the in-vehicle electric device may be restricted.

  The monitoring unit 28 acquires the output voltage value to the cold cathode tube 12 when the elapsed time from the start signal output by the timer unit 26 reaches a predetermined time. The elapsed time for the monitoring unit 28 to acquire the output voltage value is a time sufficient for a normal cold cathode tube 12 to be lit (for example, after 100 msec), before the end of the above-described activation period (for example, the activation period is 1 sec). Sometimes after 900 msec) and about halfway between them (for example, after 500 msec), it is preferable to have about three places. Here, the start-up period is 1 sec, and the elapsed time for acquiring the output voltage value is 100 msec, 500 msec, and 900 msec. Further, since the output to the cold cathode tube 12 is an alternating current, the output voltage value varies depending on the circuit configuration of the monitoring unit 28, such as an effective value and an average value, but here, for convenience, when the cold cathode tube 12 is not lit. The output voltage value is 1400V, and the output voltage value at lighting is 600V.

  Here, when there is no problem or deterioration in the cold cathode tube 12, the cold cathode tube 12 lights up within about 100 msec after the start signal is output. Therefore, as shown in FIG. 2A, the output voltage to the cold cathode tube 12 changes from 1400 V, which is the non-lighting output voltage value, to 600 V, which is the output voltage value during lighting, within 100 msec. Therefore, the output voltage values at 100 msec, 500 msec, and 900 msec acquired by the monitoring unit 28 are all 600V. Here, if the determination range of the output voltage value is around the output voltage value at lighting (here, 600 V), for example, ± 10% of the output voltage value at lighting, in the example of FIG. The output voltage values at 500 msec and 900 msec are all within the determination range. In this case, the monitoring unit 28 does not output the non-light information to the failure information generation unit 30. Therefore, the failure information generation unit 30 does not create failure information.

  Next, as shown in FIG. 2B, when the cold cathode tube 12 is lit between 100 msec and 500 msec due to the progress of deterioration of the cold cathode tube 12, the output voltage at 100 msec acquired by the monitoring unit 28. The value is 1400V and exceeds the upper limit of the determination range. In this case, the monitoring unit 28 outputs non-light information indicating that the upper limit of the determination range has been exceeded to the failure information generation unit 30. The non-light information may be digital information indicating that the upper limit of the determination range has been exceeded, but the acquired output voltage value itself may be output as non-light information.

  The failure information generation unit 30 receives the non-lamp information output from the monitoring unit 28, acquires date / time information as the date and time at that time from the clock unit 24, and creates the failure information corresponding to the non-lamp information. Then, the created failure information is recorded in the recording unit 32.

  Next, the monitoring unit 28 acquires an output voltage value at 500 msec and 900 msec. However, since the cold cathode tube 12 is lit at this time, the output voltage value at 500 msec and 900 msec takes a value of 600 V within the determination range, and no non-lamp information is output. Therefore, failure information is not created.

  Next, as shown in FIG. 2C, when the cold cathode tube 12 is lit between 500 msec and 900 msec due to further deterioration of the cold cathode tube 12, the monitoring unit 28 is not activated at 100 msec and at 500 msec. Light information is output. The failure information generation unit 30 receives the non-light information from the monitoring unit 28, acquires the date / time information at that time from the clock unit 24, creates the failure information, and records it in the recording unit 32. Therefore, in the case of FIG. 2C, two pieces of failure information are continued in a short time.

  Next, as shown in FIG. 3A, the cold-cathode tube 12 is not lit within the initial start-up period due to further deterioration of the cold-cathode tube 12, etc., and is lit between 100 msec and 500 msec of the re-lighting operation. In this case, failure information at 100 msec during the relighting operation is created in addition to failure information at 100 msec, 500 msec, and 900 msec at the initial startup period. Therefore, in this case, the failure information is continued four times in a short time. Thereafter, as the time required until the cold cathode tube 12 is turned on increases, the number of pieces of failure information that continues is increased. If the cold-cathode tube 12 is not lit at all, for example, if the re-lighting operation is performed four times, the start signal is output five times including the first lighting operation. Recording will be continued 15 times.

  In addition, when a failure such as a failure or disconnection occurs in the lighting unit 20, it is considered that no power is output from the lighting unit 20 to the cold cathode tube 12 even if a start signal is output, as shown in FIG. It is done. In such a case, the output voltage value acquired by the monitoring unit 28 is 0 V, which is below the lower limit of the determination range. In this case, the monitoring unit 28 outputs non-lamp information indicating that the lower limit of the determination range is not reached to the failure information generation unit 30. Then, the failure information generation unit 30 creates the failure information by associating the non-light information with the date / time information and records the failure information in the recording unit 32. If no power is output to the cold-cathode tube 12 even after a predetermined number of re-lighting operations, fault information indicating that the determination range is not reached is recorded 15 times continuously in this example. Further, even when the operation of the lighting unit 20 is restored for some reason, the failure information indicating that the determination range is not reached is recorded in the recording unit 32.

  In addition to non-light information and date / time information, for example, cumulative lighting time, cumulative number of activations, and the like may be added to the fault information created by the fault information generation unit 30. The cumulative lighting time is the cumulative lighting time of the cold-cathode tube 12 at the time of non-lamp information output, and the acquisition method thereof may be a separate lighting time counter for measuring the cumulative time when the cold-cathode tube 12 is lighting, The timer unit 26 or the control unit 22 may accumulate and record the output time of the start signal and approximate it as the accumulated lighting time of the cold cathode tube 12.

  The cumulative number of activations is the cumulative number of activations of the cold cathode tube 12 at the time of non-lamp information output. For example, the timer unit 26 or the control unit 22 acquires the number of activation signal outputs. The cumulative lighting time and the cumulative number of activations are reset when the cold cathode tube 12 is replaced.

  Moreover, outside temperature information is mentioned as an example of the information included in other fault information. This is the outside air temperature when the non-light information is output, and can be obtained using, for example, an outside air temperature sensor that is standardly equipped on the vehicle.

  Further, when the in-vehicle electric device is a car navigation system, the position of the vehicle when the non-light information is output may be acquired from the car navigation system, and this may be used as part of the failure information as the position information.

  Next, a method for utilizing the failure information will be described. First, when the time required until the cold-cathode tube 12 is turned on is remarkably long or does not turn on at all, the user brings the vehicle-mounted electrical equipment to the service department (repair department) together with the vehicle. The service department member sets the failure information display mode by operating the buttons of the in-vehicle electric device which has not been announced to the user, and when the cold cathode tube 12 is lit, the cold cathode tube 12 is completely displayed on the liquid crystal display 10 of the in-vehicle electric device. If it is not lit, fault information is displayed on the external display output. In addition, the display of the non-light information in the failure information is easily understood by the service department staff such as “no light” when the judgment range is exceeded, and “no output” when the judgment range is not reached. It is preferable to display it after converting it into possible words.

  Then, the service department staff confirms the displayed failure information, and if non-light information indicating that the determination range has been exceeded has frequently occurred in the past, it is determined that the cold cathode tube 12 has deteriorated and the cold cathode Replace the tube unit. Further, when there is failure information indicating that the determination range is not reached, it is estimated that the lighting unit 20 has failed, and the lighting unit 20 is mainly inspected and repaired. Further, when no failure information exists, it is estimated that no activation signal has been issued, and related parts such as the control unit 22 are inspected and repaired. Furthermore, when the failure information shows an abnormal numerical value, such as when the failure information is accumulated for a very short time or when the cumulative number of activations is extremely large, the cold cathode tube 12 or the cold cathode tube lighting device 50 is considered defective. Estimate and inspect and repair related parts. In this way, by confirming the failure information, the cause location of the failure occurrence can be specified to some extent.

  Further, when a large-scale complaint relating to the cold-cathode tube lighting device 50 occurs, the date and time information among the failure information of the cold-cathode tube lighting device 50 that has become a complaint is confirmed to be winter, summer, nighttime, daytime, etc. There may be statistical trends in the time of failure. Further, if there is outside temperature information, there is a possibility that the relationship between the obstacle factor and outside temperature can be obtained statistically. Furthermore, if there is location information, geographical factors such as concentration in specific prefectures and regions, coastal areas, mountainous areas, plains, cold areas, warm areas, altitudes, etc., can be statistically obtained. There is a possibility that. If any kind of tendency is obtained in the information, this tendency can be used as a reference for identifying the cause of the failure.

  Even if the failure of the cold-cathode tube lighting device 50 is minor and not recognized by the user, an inspection supplier or service department staff confirms the failure information during periodic vehicle inspections, etc. Can be found. If the failure information shows signs of deterioration in the cold cathode tube 12, the user can be recommended to replace the cold cathode tube unit. Further, as described above, the degree of deterioration of the cold cathode tube 12 can be grasped to some extent by the number of times the failure information is continued. Based on this information, an indication of the replacement timing of the cold cathode tube unit is presented to the user. can do. At this time, if the failure information has a cumulative lighting time and a cumulative number of activations, a more accurate replacement time can be presented.

  Further, when signs of deterioration of the cold cathode fluorescent lamp 12 are recognized in a very short period of time than usual, or failure information of no output of the lighting unit 20 is confirmed, the failure information is transmitted to the development department or the production department. The cause investigation, countermeasures, and quality improvement can be performed at an early stage. As a result, the quality of the current or future cold cathode tube lighting device 50 can be improved.

  When the cumulative number of failure information indicating the deterioration of the cold cathode tube 12 exceeds a certain number or continues for a predetermined number of times, the cold cathode tube unit is immediately replaced with the liquid crystal display 10 or the warning light of the vehicle. The display may be displayed to notify the user of the deterioration of the cold cathode tube 12.

  As described above, according to the cold cathode tube lighting device 50 according to the present invention, when a failure occurs when the cold cathode tube 12 is turned on, the failure information is recorded. Then, by confirming the failure information at a later date, the cause of the failure can be specified to some extent. Further, when the cold cathode tube 12 is deteriorated, the degree of deterioration of the cold cathode tube 12 can be grasped to some extent from the failure information. Therefore, it is possible to present an indication of the replacement of the cold cathode tube unit and the replacement time to the user.

  In addition, since said cold cathode tube lighting device 50 is an example, the structure of each block, the acquisition time of an output voltage value, the frequency | count, other numerical values, etc. can be changed suitably. In addition, the present invention can be modified and implemented without departing from the gist of the present invention.

10 Liquid crystal display
12 Cold cathode tubes
20 lighting part
22 Control unit
24 Clock part
26 Timer section
28 Monitoring unit
30 Fault information generator
32 Recording unit
50 Cold cathode tube lighting device

Claims (1)

A lighting unit for lighting a cold cathode tube as a light source of a liquid crystal display;
A control unit for outputting a start signal for lighting the cold cathode tube with respect to the lighting unit;
In a cold cathode tube lighting device having:
A clock section for acquiring date and time information;
A timer unit for measuring an elapsed time since the start signal is output;
A monitoring unit that obtains a value of an output voltage to the cold-cathode tube when the elapsed time reaches a predetermined value and outputs non-lamp information when the value of the output voltage is outside a predetermined determination range; ,
A failure information generating unit that receives the output of the non-lamp information and creates fault information including non-lamp information and date and time information;
A recording unit for recording the failure information;
A cold-cathode tube lighting device comprising:

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