JP2009206036A - Lighting system, display device, and television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system capable of surely preventing secondary abnormality from occurring when abnormality occurs and excelling in safety; a display device using it; and a television receiver. <P>SOLUTION: This lighting system is provided with: hot-cathode fluorescent tubes (light sources) 9; a plurality of inverter circuits (lighting drive circuits) 16 lighting and driving the hot-cathode fluorescent tubes 9; and a lighting control part (control part) 15 controlling the drive of the inverter circuits 16. In the lighting system, the lighting control part 15 generates an error signal when abnormality of at least either of the hot-cathode fluorescent tubes 9 and the inverter circuits 16 is detected, stops the power supply to the inverter circuit 16 having the detected abnormality and the power supply to the inverter circuit 16 driving the lighting of the hot-cathode fluorescent tube 9 having the detected abnormality, and stops power supply to all the rest of the inverter circuits 16 when a first threshold time elapses from the time the error signal is generated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lighting device used for a backlight or the like, a display device using the same, and a television receiver.

  In recent years, for example, in a television receiver for home use, as represented by a liquid crystal display device, a display device provided with a liquid crystal panel as a flat display portion having many features such as a thinner and lighter than a conventional cathode ray tube. Is becoming mainstream. Such a liquid crystal display device includes an illumination device (backlight) that emits light, and a liquid crystal panel that displays a desired image by serving as a shutter for light from a light source provided in the illumination device. Is provided. In the television receiver, information such as characters and images included in the video signal of the television broadcast is displayed on the display surface of the liquid crystal panel.

  The illumination device is roughly classified into a direct type and an edge light type depending on the arrangement of the light source with respect to the liquid crystal panel. However, a liquid crystal display device having a liquid crystal panel of 20 inches or more is higher than the edge light type. A direct-type illumination device that is easy to increase in luminance and size is generally used. In other words, the direct type lighting device is configured by arranging a plurality of light sources on the back (non-display surface) side of the liquid crystal panel, and since a light source can be arranged immediately behind the liquid crystal panel, a large number of light sources are used. Therefore, it is easy to obtain high luminance and suitable for high luminance and large size. In addition, the direct type illumination device is suitable for high luminance and large size because the inside of the device has a hollow structure and is light even if it is large.

Further, in the conventional illumination device as described above, for example, as described in Patent Document 1 below, a plurality of fluorescent lamps (light sources) are provided, and an odd-numbered fluorescent lamp is driven by the first drive system, In addition, it has been proposed to drive even-numbered fluorescent lamps by the second drive system. In this conventional illumination device, when an abnormality occurs in the odd-numbered fluorescent lamp or the even-numbered fluorescent lamp, only the driving of the corresponding first or second drive system is stopped, thereby causing a decrease in luminance. It was possible to prevent luminance unevenness while suppressing the above.
JP 2007-18847 A

  However, in the conventional lighting device as described above, the fluorescent lamp in which an abnormality has occurred is not properly replaced, and a secondary abnormality occurs in another fluorescent lamp (light source) or drive system (lighting drive circuit). There was a risk that it could not be prevented reliably.

  Specifically, in the conventional lighting device, when an abnormality occurs in one of the odd-numbered and even-numbered fluorescent lamps, the drive system that drives the other fluorescent lamp is merely stopped. As a result, depending on the number of fluorescent lamps installed, the configuration of the drive system, or the elapsed time until the replacement of the fluorescent lamp, the load on the fluorescent lamps and drive system that continued to drive increased, and secondary There was a risk of an abnormality.

  Further, in this conventional illumination device, when an abnormality of the fluorescent lamp is detected, the abnormality of the fluorescent lamp is notified to the liquid crystal display device side, and the fluorescent lamp abnormality is displayed on the screen of the liquid crystal display device by OSD (On-Screen Display). It is also shown to be displayed. However, only by performing such OSD display, the user does not replace the fluorescent lamp in which an abnormality has occurred, and the fluorescent lamp is not appropriately replaced, thereby reliably preventing the occurrence of a secondary abnormality. You may not be able to.

  In view of the above-described problems, the present invention provides an illumination device excellent in safety capable of reliably preventing a secondary abnormality from occurring when an abnormality occurs, a display device using the same, and a television set. An object is to provide a receiving apparatus.

In order to achieve the above object, an illumination device according to the present invention is an illumination device including a light source,
A plurality of lighting drive circuits for lighting the light source;
A control unit that performs drive control of the lighting drive circuit;
The control unit generates an error signal when detecting an abnormality in at least one of the light source and the lighting driving circuit, and also turns on a lighting driving circuit that detects the abnormality and a light source that detects the abnormality. The power supply to all the lighting drive circuits is stopped when the first threshold time has elapsed from the time when the error signal is generated and the power supply to the power supply is stopped. It is.

  In the illumination device configured as described above, the control unit generates an error signal when detecting an abnormality in at least one of the light source and the lighting drive circuit, and also detects the lighting drive circuit that detects the abnormality and the light source that detects the abnormality. Each power supply to the lighting drive circuit that drives the lighting is stopped. In addition, when the first threshold time elapses from the time when the error signal is generated, the control unit stops the power supply to all the remaining lighting drive circuits. Accordingly, unlike the conventional example, it is possible to configure a lighting device with excellent safety that can reliably prevent the occurrence of a secondary abnormality when an abnormality occurs.

  In the lighting device, it is preferable that the control unit outputs the error signal to the outside to notify the outside that an abnormality has occurred.

  In this case, it is possible to notify the outside that an abnormality has occurred in at least one of the light source and the lighting drive circuit, and to allow the user to immediately recognize the occurrence of the abnormality.

  Further, in the illumination device, when the control unit detects an abnormality of the light source or any of the plurality of lighting drive circuits, until the second threshold time elapses after the abnormality is detected. The error signal may be generated when the number of times of abnormality detection for the light source or lighting drive circuit that detected the abnormality exceeds a predetermined number.

  In this case, it is possible to prevent malfunction of abnormality detection.

  In addition, the display device of the present invention is characterized by using any one of the above illumination devices.

  In the display device configured as described above, since an illumination device with excellent safety that can reliably prevent the occurrence of a secondary abnormality when an abnormality occurs, an excellent safety is used. A highly reliable display device having high reliability can be easily configured.

Moreover, in the said display apparatus, while providing the display part which displays information,
When the error signal is input from the control unit, the display unit is preferably configured to display a predetermined warning screen.

  In this case, since the display unit displays the warning screen, the user can surely recognize that an abnormality has occurred in at least one of the light source and the lighting drive circuit.

  The television receiver of the present invention is characterized by using any of the above display devices.

  In the television receiver configured as described above, since an illumination device with excellent safety that can reliably prevent the occurrence of a secondary abnormality when an abnormality has occurred, the television receiver is excellent. A highly reliable television receiver having safety can be easily configured.

  ADVANTAGE OF THE INVENTION According to this invention, when abnormality generate | occur | produces, the lighting apparatus excellent in safety | security which can prevent reliably that secondary abnormality arises, a display apparatus using the same, and a television receiver are provided. It becomes possible to do.

  Hereinafter, preferred embodiments of a lighting device of the present invention, a display device using the same, and a television receiver will be described with reference to the drawings. In the following description, the case where the present invention is applied to a transmissive liquid crystal display device will be described as an example. Moreover, the dimension of the structural member in each figure does not faithfully represent the actual dimension of the structural member, the dimensional ratio of each structural member, or the like.

  FIG. 1 is an exploded perspective view illustrating a television receiver and a liquid crystal display device according to an embodiment of the present invention. In the figure, a television receiver 1 of this embodiment includes a liquid crystal display device 2 as a display device, and is configured to be able to receive a television broadcast by an antenna, a cable (not shown), or the like. The liquid crystal display device 2 is erected by a stand 5 while being housed in the front cabinet 3 and the back cabinet 4. In the television receiver 1, the display surface 2 a of the liquid crystal display device 2 is configured to be visible through the front cabinet 3. The display surface 2a is installed by the stand 5 so as to be parallel to the direction of gravity action (vertical direction).

  In the television receiver 1, a control circuit for controlling each part of the television receiver 1 such as a TV tuner circuit board 6 a attached to the support plate 6 and a lighting device described later between the liquid crystal display device 2 and the back cabinet 4. A board 6b and a power circuit board 6c are arranged. In the television receiver 1, an image corresponding to the video signal of the television broadcast received by the TV tuner on the TV tuner circuit board 6 a is displayed on the display surface 2 a and the speaker 3 a provided in the front cabinet 3. Audio is played out. The back cabinet 4 is formed with a large number of ventilation holes so that heat generated by the lighting device, the power source, etc. can be appropriately dissipated.

  Next, the liquid crystal display device 2 will be specifically described with reference to FIG.

  FIG. 2 is a diagram for explaining a main configuration of the liquid crystal display device. In the figure, the liquid crystal display device 2 includes a liquid crystal panel 7 as a display unit for displaying information such as characters and images, and the liquid crystal panel 7 disposed on the non-display surface side (the lower side of the figure). The illumination device 8 of the present invention that generates illumination light for illuminating 7 is provided. The liquid crystal panel 7 and the illumination device 8 are integrated as a transmissive liquid crystal display device 2. In the liquid crystal display device 2, a pair of polarizing plates 12 and 13 whose transmission axes are arranged in crossed Nicols are provided on the non-display surface side and the display surface side of the liquid crystal panel 7, respectively.

  The lighting device 8 is provided with a bottomed casing 8a and a plurality of (for example, eight) hot cathode fluorescent tubes 9 housed in the casing 8a at equal pitches. For example, a reflection sheet 8b is installed on the inner surface of the casing 8a, and the light utilization efficiency of the hot cathode fluorescent tube 9 is improved by reflecting light from the hot cathode fluorescent tube 9 as a light source to the liquid crystal panel 7 side. It is designed to improve.

  Each hot cathode fluorescent tube 9 has a straight tube shape, and electrode portions (not shown) provided at both ends thereof are supported outside the casing 8a. Each hot cathode fluorescent tube 9 has a diameter of about 10 to 40 mm. Each hot cathode fluorescent tube 9 is held inside the casing 8a in a state in which the distance between the diffusion plate 10 and the reflection sheet 8b is kept at a predetermined distance by a light source holder (not shown).

  Further, the plurality of hot cathode fluorescent tubes 9 are arranged so that the longitudinal direction thereof is parallel to the direction orthogonal to the direction of gravity. As a result, in the hot cathode fluorescent tube 9, mercury (vapor) enclosed therein is prevented from collecting on one end side in the longitudinal direction due to the action of gravity, and the lamp life is greatly improved. Yes.

  Further, on the outside of the casing 8a, a liquid crystal driving unit 14 for driving the liquid crystal panel 7, an illumination control unit 15 as a control unit of the illumination device 8, and a control signal (instruction signal) from the illumination control unit 15 are used. Thus, an inverter circuit 16 is installed to turn on each of the plurality of hot cathode fluorescent tubes 9 at a high frequency by inverter driving. The liquid crystal drive unit 14, the illumination control unit 15, and the inverter circuit 16 are provided on the control circuit board 6b (FIG. 1), and are arranged to face the outside of the casing 8a.

  In the lighting device 8, a diffusion plate 10 installed so as to cover the opening of the casing 8 a and an optical sheet 11 installed above the diffusion plate 10 are provided. The diffusion plate 10 is configured using, for example, a rectangular synthetic resin or glass material having a thickness of about 2 mm. Further, the diffusion plate 10 is movably held on the casing 8a, and expands and contracts (plasticity) on the diffusion plate 10 due to the influence of heat such as heat generation of the hot cathode fluorescent tube 9 and temperature rise inside the casing 8a. Even when deformation occurs, the deformation can be absorbed by moving on the casing 8a.

The optical sheet 11 includes a diffusion sheet made of, for example, a synthetic resin film having a thickness of about 0.2 mm. The optical sheet 11 appropriately diffuses the illumination light to the liquid crystal panel 7 and displays the liquid crystal panel 7. The display quality on the screen is improved. The optical sheet 11 is appropriately laminated with a known optical sheet material such as a prism sheet or a polarization reflecting sheet for improving display quality on the display surface of the liquid crystal panel 7 as necessary. ing. The optical sheet 11 converts the planar light emitted from the diffusing plate 10 into planar light having a predetermined luminance (for example, 10000 cd / m ² ) or more and substantially uniform luminance. As shown in FIG.

  In addition to the above description, for example, an optical member such as a diffusion sheet for adjusting the viewing angle of the liquid crystal panel 7 may be appropriately laminated above the liquid crystal panel 7 (display surface side).

  Here, the illuminating device 8 of the present embodiment will be specifically described with reference to FIGS.

  FIG. 3 is a diagram for explaining a main configuration of the illumination device shown in FIG. 2, and FIG. 4 is a block diagram showing a specific configuration of the illumination control unit shown in FIG.

  As shown in FIG. 3, the illumination device 8 is provided with the illumination control unit 15 for controlling the driving of each of the plurality of hot cathode fluorescent tubes 9 and the hot cathode fluorescent tube 9. The inverter circuit 16 is installed as a lighting drive circuit for lighting the corresponding hot cathode fluorescent tube 9 based on the instruction signal. The inverter circuit 16 is installed on one end side in the longitudinal direction of each hot cathode fluorescent tube 9. The inverter circuit 16 is, for example, a half-bridge type, and the inverter circuit 16 can drive the corresponding hot cathode fluorescent tube 9 using, for example, PWM dimming based on the instruction signal. It is configured.

  The illuminating device 8 includes a lamp current detection circuit RC that is provided for each hot cathode fluorescent tube 9 and detects a lamp current value flowing through the corresponding hot cathode fluorescent tube 9. The lamp current value detected by the lamp current detection circuit RC is output to the illumination control unit 15 via a feedback circuit FB installed according to each hot cathode fluorescent tube 9. Further, as will be described in detail later, the illumination control unit 15 uses the lamp current value from the feedback circuit FB to detect the presence / absence of an abnormality in the corresponding hot cathode fluorescent tube 9.

  Further, for example, a dimming instruction signal for changing the luminance of the light-emitting surface of the illuminating device 8 is input to the illumination control unit 15 as an instruction signal from the outside. The luminance (brightness) on the display surface of the liquid crystal panel 7 can be changed as appropriate. That is, the illumination control unit 15 is configured to receive a dimming instruction signal from an operation input device (not shown) such as a remote controller provided on the liquid crystal display device 1 side, for example. And the illumination control part 15 determines the target value of the electric current supplied to each hot cathode fluorescent tube 9 while determining the duty ratio in PWM dimming using the input dimming instruction signal. ing.

  Thereafter, the illumination control unit 15 generates and outputs an instruction signal to each inverter circuit 16 based on the determined target value, whereby the lamp current value flowing through the corresponding hot cathode fluorescent tube 9 changes. As a result, the amount of emitted light emitted from each hot cathode fluorescent tube 9 changes according to the dimming instruction signal, and the luminance on the light emitting surface of the illumination device 8 and the luminance on the display surface of the liquid crystal panel 7 are changed. It is changed appropriately according to the user's operation instruction.

  The lamp current value actually supplied to each hot cathode fluorescent tube 9 is fed back as a detected current value to the illumination control unit 15 via the corresponding lamp current detection circuit RC and feedback circuit FB. Then, the illumination control unit 15 performs feedback control using the detected current value and the target value of the supply current determined based on the dimming instruction signal, so that display with the brightness desired by the user is performed. Is maintained.

  As shown in FIG. 4, the illumination control unit 15 is provided with a dimming signal generation unit 15a, and the inverter circuit 16 connected to each hot cathode fluorescent tube 9 based on the dimming instruction signal. An instruction signal is generated and output.

  Moreover, the illumination control unit 15 includes an abnormality detection unit 15b, a counter 15c, an error signal output unit 15d, a timer 15e, and a stop signal output unit 15f, and detects an abnormality in at least one of the hot cathode fluorescent tube 9 and the inverter circuit 16. When detected, an error signal is generated, and each power supply to the inverter circuit 16 that detects the abnormality and the inverter circuit 16 that drives the lighting of the hot cathode fluorescent tube 9 that detects the abnormality is stopped. . Further, as will be described in detail later, the illumination control unit 15 stops supplying each power to all the remaining inverter circuits 16 when a predetermined time (first threshold time) has elapsed since the time when the error signal was generated. It is supposed to let you.

  Further, in the illumination control unit 15, each of the above-described units is configured using an IC, an ASIC, or the like. Furthermore, the illumination control unit 15 is provided with a memory 15g, and the detection result in the abnormality detection unit 15b. Further, predetermined information such as the output result of each output signal from the error signal output unit 15d or the stop signal output unit 15f is stored.

  In addition, the dimming signal generation unit 15a is provided with a duty ratio determination unit 15a1, and this duty ratio determination unit 15a1 uses the dimming instruction signal from the outside to perform PWM for each hot cathode fluorescent tube 9. A duty ratio between an on period and an off period in a PWM cycle in dimming is determined. Then, the dimming signal generation unit 15a generates a dimming signal having a predetermined dimming frequency in PWM dimming based on the determined duty ratio, and includes the dimming signal in the instruction signal to the corresponding inverter circuit 16. It is designed to output.

  The abnormality detection unit 15b is configured to detect an abnormality in at least one of the hot cathode fluorescent tube 9 and the inverter circuit 16. Specifically, the abnormality detection unit 15b uses the lamp current value from the feedback circuit FB to determine whether or not an abnormality such as lamp non-lighting has occurred in the corresponding hot cathode fluorescent tube 9. It has become. In the abnormality detection unit 15b, an abnormality detection line (not shown) is provided between each of the plurality of inverter circuits 16, and when an abnormality such as an operation failure occurs in the inverter circuit 16, the abnormality is detected. Is notified to the abnormality detection unit 15b via the abnormality detection line and detected.

  The counter 15c counts the number of times that the abnormality detection unit 15b performs abnormality detection within a preset setting time (second threshold time) for each of the plurality of hot cathode fluorescent tubes 9 and each of the plurality of inverter circuits 16. Is configured to do. Thereby, in the illuminating device 8 of this embodiment, it can prevent that malfunction of abnormality detection arises (it mentions later for details).

  The error signal output unit 15d is configured to generate an error signal using the count result of the counter 15c and output the error signal to the stop signal output unit 15f. As described in detail later, an abnormality is detected. Each power supply to the inverter circuit 16 and the inverter circuit 16 that drives and lights the hot cathode fluorescent tube 9 in which an abnormality is detected is stopped.

  Further, the error signal output unit 15d outputs the generated error signal to the outside of the lighting device 8. That is, the illumination control unit 15 is configured to notify the detected abnormality to the outside by the error signal output unit 15d when the abnormality of at least one of the hot cathode fluorescent tube 9 and the inverter circuit 16 is detected. . Thereby, in the illuminating device 8 of this embodiment, the occurrence of the abnormality can be immediately recognized by the user.

  Specifically, the error signal output unit 15 d outputs the generated error signal to the liquid crystal drive unit 14. The liquid crystal drive unit 14 creates a predetermined warning screen including the position and content of abnormality of the hot cathode fluorescent tube 9 or the inverter circuit 16 where the abnormality has occurred, according to the error signal from the error signal output unit 15d. Thus, the information is displayed on the liquid crystal panel (display unit) 7.

  Note that the output destination of the error signal from the error signal output unit 15d is not limited to the liquid crystal drive unit 14, but includes a plurality of light emitting elements such as LEDs, and the error signal from the error signal output unit 15d. In response to this, an error signal may be output to reporting means for reporting the hot cathode fluorescent tube 9 or the inverter circuit 16 that has malfunctioned when any one of the light emitting elements is lit (emitted).

  When the error signal output unit 15d generates an error signal, the timer 15e measures an elapsed time from the generation point. Then, when the measurement time exceeds the predetermined time, the timer 15e is configured to notify the stop signal output unit 15f that the predetermined time has been exceeded.

  When the error signal is input from the error signal output unit 15d, the stop signal output unit 15f receives the inverter circuit 16 corresponding to at least one of the hot cathode fluorescent tube 9 and the inverter circuit 16 in which the abnormality indicated by the error signal is detected. A stop signal for stopping the power supply to is generated.

  That is, when an error signal is generated and input to the stop signal output unit 15f corresponding to any one of the plurality of hot cathode fluorescent tubes 9, the stop signal output unit 15f is based on the input error signal. The hot cathode fluorescent tube 9 in which an abnormality is detected is determined, and the stop signal is output to the inverter circuit 16 that drives the determined hot cathode fluorescent tube 9 to turn on. The power supply from the power supply in which is omitted is stopped. In addition, when an error signal is generated and input to the stop signal output unit 15f corresponding to any one of the plurality of inverter circuits 16, the stop signal output unit 15f has an abnormality based on the input error signal. The detected inverter circuit 16 is discriminated, and further, the stop signal is output to the discriminated inverter circuit 16 to stop the power supply from the power source to the inverter circuit 16.

  Further, when the stop signal output unit 15f is notified from the timer 15e that the elapsed time from the time when the error signal is generated exceeds the predetermined time, the stop signal output unit 15f Is output to stop the power supply to all these inverter circuits 16.

  In the above description, the configuration in which the power supply to the inverter circuit 16 that detects abnormality and the inverter circuit 16 that drives the hot cathode fluorescent tube 9 that detects abnormality is stopped has been described. For example, a protection circuit may be provided for each inverter circuit, and when the error signal is generated, the protection circuit may stop the operation of the corresponding inverter circuit.

  Here, the operation of the liquid crystal display device 2 of the present embodiment configured as described above will be described. In the following description, the abnormality detection operation and the stop operation in the illumination device 8 will be mainly described.

  FIG. 5 is a flowchart showing the operation of the liquid crystal display device.

  As shown in step S <b> 1 of FIG. 5, in the illumination control unit 15, the abnormality detection unit 15 b detects whether or not an abnormality has occurred in at least one of the hot cathode fluorescent tube 9 and the inverter circuit 16. If the abnormality detection unit 15b does not detect an abnormality, the abnormality detection unit 15b enters a standby state.

  On the other hand, when the abnormality detection unit 15b detects an abnormality, the counter 15c performs the number of times for each of the plurality of hot cathode fluorescent tubes 9 and each of the plurality of inverter circuits 16 (step S2). Further, the counter 15c includes an abnormality detection unit until a preset time (second threshold time, for example, 60 seconds) elapses for each of the plurality of hot cathode fluorescent tubes 9 and each of the plurality of inverter circuits 16. It is determined whether or not the number of times 15b has detected an abnormality exceeds a predetermined number (for example, 5 times). When the counter 15c determines that the number of times of abnormality detection has exceeded the predetermined number of times within the set time, the counter 15c outputs the count result to the error signal output unit 15d.

  Subsequently, the error signal output unit 15d generates an error signal using the count result of the counter 15c, and outputs the error signal to the stop signal output unit 15f. Then, the stop signal output unit 15f outputs a stop signal to the corresponding inverter circuit 16, and the power supply to the inverter circuit 16 is stopped (step S4). Thereby, only the power supply to the inverter circuit 16 in which the abnormality is detected and the inverter circuit 16 for the hot cathode fluorescent tube 9 in which the abnormality is detected is stopped. Further, since only the hot cathode fluorescent tube 9 connected to the inverter circuit 16 in which the abnormality is detected in this manner is turned off, it is possible to suppress a reduction in light emission quality associated with the turning off of the hot cathode fluorescent tube 9 as much as possible.

  In step S4, the timer 15e starts timer measurement (time measurement) from the time when the error signal is generated by the error signal output unit 15d. Further, the error signal output unit 15 d outputs the generated error signal to the liquid crystal drive unit 14. Then, in the liquid crystal drive unit 14, a predetermined warning screen including the position and content of abnormality of the hot cathode fluorescent tube 9 or the inverter circuit 16 in which an abnormality has occurred is created according to the error signal from the error signal output unit 15d. And displayed on the liquid crystal panel (display unit) 7. In other words, in the present embodiment, an alert display for abnormality detection is performed on the liquid crystal panel 7, and the user is required to perform replacement work for the hot cathode fluorescent tube 9 and the inverter circuit 16 that have detected the abnormality.

  In the warning screen, it is necessary to request replacement work of the hot cathode fluorescent tube 9 or the inverter circuit 16 in which the abnormality is detected according to the positions of the hot cathode fluorescent tube 9 or the inverter circuit 16 in which the abnormality detection unit 15b detects the abnormality. The position of the included alert display is appropriately changed. That is, in the illuminating device 8 of the present embodiment, only the hot cathode fluorescent tube 9 connected to the inverter circuit 16 in which the abnormality is detected is turned off, which is different from the turned off hot cathode fluorescent tube 9. The alert display is performed at a position on the liquid crystal panel 7. Thereby, in this embodiment, it is possible to reliably notify the user of abnormality detection and replacement work requests.

  Next, the timer 15e determines whether or not the elapsed time from the time when the error signal is generated exceeds a predetermined time (first threshold time, for example, 10 hours) (step S5). When the time measured by the timer 15e exceeds a predetermined time, the timer 15e notifies the stop signal output unit 15f that the predetermined time has been exceeded.

  Subsequently, the stop signal output unit 15f outputs a stop signal to all the remaining inverter circuits 16, and stops each power supply to all the inverter circuits 16 (step S6). Thereby, in the illuminating device 8 of this embodiment, irradiation of the illumination light to the liquid crystal panel 7 is stopped. As a result, in the television receiver 1 according to the present embodiment, the video cannot be displayed, and is substantially the same as the state where the power supply is shut down.

  Further, as described above, when the stop signal output unit 15f stops all the inverter circuits 16, in the illumination device 8 of the present embodiment, the hot cathode fluorescent tube 9 or the inverter circuit 16 in which the abnormality is detected is replaced. The stop of all the inverter circuits 16 cannot be released until the lighting control unit 15 detects that the work has been properly completed.

  In addition to the above description, the stop signal output unit 15f stops the power of the liquid crystal display device 2 and the power of the television receiver 1 when outputting a stop signal to all the remaining inverter circuits 16. An instruction signal to be instructed may be output to the liquid crystal driving unit 14 or a control circuit (not shown) on the television receiver 1 side.

  In the illumination device 8 of the present embodiment configured as described above, the illumination control unit (control unit) 15 detects an abnormality in at least one of the hot cathode fluorescent tube (light source) 9 and the inverter circuit (lighting drive circuit) 16. Sometimes it generates an error signal. Moreover, the illumination control unit 15 stops each power supply to the inverter circuit 16 that detects the abnormality and the inverter circuit 16 that drives the lighting of the hot cathode fluorescent tube 9 that detects the abnormality. Furthermore, the illumination control unit 15 stops each power supply to all the remaining inverter circuits 16 when a predetermined time (first threshold time) has elapsed since the time when the error signal was generated. As a result, in the present embodiment, unlike the conventional example, it is possible to configure the lighting device 8 with excellent safety capable of reliably preventing the occurrence of a secondary abnormality when an abnormality occurs. .

  Moreover, in the liquid crystal display device 2 of this embodiment, when the error signal from the illumination control unit 15 is input, the liquid crystal panel (display unit) 7 is configured to display a predetermined warning screen. The user can be surely recognized that an abnormality has occurred in at least one of the cathode fluorescent tube 9 and the inverter circuit 15.

  In the television receiver 1 and the liquid crystal display device 2 of the present embodiment, the lighting device 8 with excellent safety that can surely prevent the occurrence of a secondary abnormality when an abnormality occurs is used. Therefore, the highly reliable television receiver 1 and liquid crystal display device 2 having excellent safety can be easily configured.

  The above embodiments are all illustrative and not restrictive. The technical scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the technical scope of the present invention.

  For example, in the above description, the case where the present invention is applied to a transmissive liquid crystal display device has been described. However, the lighting device of the present invention is not limited to this, and the image, The present invention can be applied to various display devices including a non-light emitting display unit that displays information such as characters. Specifically, the illumination device of the present invention can be suitably used for a transflective liquid crystal display device or a projection display device using a liquid crystal panel as a light valve.

  In the above description, the case where a hot cathode fluorescent tube is used has been described. However, the light source of the present invention is not limited to this, and other discharge fluorescent tubes such as a cold cathode fluorescent tube and a xenon fluorescent tube, Alternatively, a non-straight tubular discharge fluorescent tube such as a U-shaped tube or a pseudo-U-shaped tube may be used. Furthermore, a light emitting element such as a light emitting diode (LED) or an organic EL (Electro-Luminescence) can be used as a light source.

  That is, the present invention includes a lighting drive circuit that is connected to a light source and drives the light source to turn on, and a control unit that controls driving of the lighting drive circuit, and the control unit detects an abnormality in at least one of the light source and the lighting drive circuit. When the error signal is generated, the power supply to the lighting drive circuit that detects the abnormality and the lighting drive circuit that drives the light source that detects the abnormality is stopped, and the error signal is generated from the time when the error signal is generated. What is necessary is just to stop the power supply to all the remaining lighting drive circuits when the threshold time of 1 has passed, and what kind of light source type, number of installations, drive system, or configuration of the lighting drive circuit, etc. It is not limited to those.

  Specifically, in the above description, a case where an inverter circuit is connected to each hot cathode fluorescent tube to drive lighting is described. However, a plurality of hot cathode fluorescent tubes are turned on by one lighting drive circuit. It may be configured to drive. In addition, when a mercury-less discharge fluorescent tube such as the xenon fluorescent tube is used, a long-life lighting device having discharge tubes arranged in parallel to the direction of gravity can be configured.

  INDUSTRIAL APPLICABILITY The present invention is useful for a lighting device excellent in safety capable of reliably preventing a secondary abnormality from occurring when an abnormality occurs, a display device using the same, and a television receiver. It is.

It is a disassembled perspective view explaining the television receiver and liquid crystal display device concerning one Embodiment of this invention. It is a figure explaining the principal part structure of the said liquid crystal display device. It is a figure explaining the principal part structure of the illuminating device shown in FIG. It is a block diagram which shows the specific structure of the illumination control part shown in FIG. It is a flowchart which shows operation | movement of the said liquid crystal display device.

Explanation of symbols

1 TV receiver 2 Liquid crystal display device (display device)
7 LCD panel (display unit)
8 Lighting equipment 9 Hot cathode fluorescent tube (light source)
15 Lighting control unit (control unit)
16 Inverter circuit (lighting drive circuit)

Claims (6)

A lighting device comprising a light source,
A plurality of lighting drive circuits for lighting the light source;
A control unit that performs drive control of the lighting drive circuit;
The control unit generates an error signal when detecting an abnormality in at least one of the light source and the lighting driving circuit, and also turns on a lighting driving circuit that detects the abnormality and a light source that detects the abnormality. And when the first threshold time has elapsed since the time when the error signal was generated, the power supply to all the remaining lighting drive circuits is stopped.
A lighting device characterized by that. The lighting device according to claim 1, wherein the control unit outputs the error signal to the outside to notify the outside that an abnormality has occurred. When the controller detects an abnormality in the light source or any one of the plurality of lighting drive circuits, the light source or lighting in which the abnormality is detected until the second threshold time elapses after the abnormality is detected. The lighting device according to claim 1, wherein the error signal is generated when the number of abnormality detections for the drive circuit exceeds a predetermined number. A display device using the illumination device according to claim 1. A display unit for displaying information is provided.
The display device according to claim 4, wherein, when the error signal is input from the control unit, the display unit is configured to display a predetermined warning screen. A television receiver using the display device according to claim 4.

Images