JP5004288B2 - Display device and lighting system thereof - Google Patents

Description

  The present invention relates to a display device such as a liquid crystal television and a personal computer and a lighting system thereof.

  Since a display device such as a liquid crystal television does not emit light itself, a separate light source is required. A backlight is used as the light source. The backlight has a configuration in which a lamp such as a cold cathode discharge lamp is disposed inside the casing.

  The inside of such a backlight is a so-called dark space in which no external light is incident, and it is known that the starting characteristics of the lamp are not good in that space. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 1-130462 (hereinafter referred to as Patent Document 1), an attempt is made to prompt the start of the discharge lamp by arranging an auxiliary light source such as a light emitting diode (hereinafter referred to as LED) or a small light bulb in the vicinity of the lamp. Has been.

  Several proposals have also been made regarding the lighting control of the auxiliary light source. For example, in Japanese Patent Laid-Open No. 1-294348 (hereinafter referred to as Patent Document 2), as shown in FIG. 16, the auxiliary light source is turned on simultaneously with a lighting instruction to the lamp, and a predetermined time is set by a timer. The contents of turning off the auxiliary light source after the passage are described. Japanese Patent Laid-Open No. 2001-313189 (hereinafter referred to as Patent Document 3), as shown in FIG. 3, detects the output voltage of the inverter lighting device, and assists when the output voltage exceeds a predetermined value. The contents of turning on the light source and turning off the auxiliary light source when the output voltage falls below a predetermined value are described.

Japanese Patent Laid-Open No. 1-130462 JP-A-1-294348 JP 2001-313189 A

  However, since Patent Documents 1 to 3 are systems in which the auxiliary light source is turned on at the same time that the discharge lamp is turned on, it takes time to supply initial electrons to the discharge lamp. Therefore, a time lag occurs in the discharge start of the discharge lamp, and a discharge delay occurs even though it is a short time.

  An object of the present invention is to provide a display device having excellent dark start characteristics and a lighting system thereof.

To achieve the above object, a display device of the present invention comprises a housing, disposed within the housing, and the external electrode discharge lamp with external electrodes on both ends of the discharge vessel, the neighborhood of the discharge vessel An auxiliary light source disposed on the power source , a power switch electrically connected to a main power source , which can be turned on or off by a user, an input side is electrically connected to an off side of the power switch, and an output side is A first lighting circuit electrically connected to the auxiliary light source; an input side electrically connected to an ON side of the power switch; and an output side electrically connected to the external electrode discharge lamp. And when the user turns on the power switch, the second lighting circuit is turned on, the external electrode discharge lamp is turned on, and the first lighting circuit is turned off. the become of the state Part electrodeless discharge lamp wherein an auxiliary light source lit up lights up just before turned off, the when the user turns off the power switch, the second lighting circuit is the external electrode discharge lamp turned off is turned off The first lighting circuit is turned on and the auxiliary light source is turned on.

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus excellent in the dark starting characteristic and its lighting system can be provided.

(First embodiment)
Hereinafter, a display device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining a display device according to a first embodiment of the present invention.

  The housing of the display device includes a front frame 101 and a back frame 102. The front frame 101 has an opening serving as a light emitting surface in the display device, and a liquid crystal panel 103 is disposed in the opening. Further, the front frame 101 is provided with a power switch 1011 for switching the display device to an on state or an off state. The back frame 102 has a shape in which a stand is attached to a lower portion of a case having a bottomed opening, and a backlight 104 is disposed inside the case having the bottomed opening.

  The configuration of the backlight 104 will be described in detail. FIG. 2 is a diagram for explaining the backlight, and FIG. 3 is a diagram for explaining a cross-section in the arrow direction of A-A ′ in FIG. 2.

  The casing of the backlight 104 includes a front case 1a and a back case 1b made of, for example, white plastic. The front case 1a is formed with an opening 1a1 for taking out light from a discharge lamp 3 described later. The back case 1b has a bottomed opening shape, and a highly reflective reflective surface is formed on the inner wall surface by a reflective sheet or silver vapor deposition. In addition, metal lamp holders 2a and 2b are disposed at the bottom of the back case 1b.

  Inside the back case 1b, a plurality of elongated discharge lamps 3 are arranged so that their tube axes are substantially parallel. The discharge lamp 3 of the present embodiment is an external electrode discharge lamp, that is, both ends of a glass bulb 31 in which a rare gas such as neon or argon and mercury are enclosed and a phosphor layer is formed on the inner wall surface. The external electrodes 32a and 32b are formed on the surface. The discharge lamp 3 is mechanically held and electrically connected to the discharge lamp 3 by holding the external electrodes 32a and 32b with a pair of lamp holders 2a and 2b.

  In the vicinity of the glass bulb 31 of the discharge lamp 3, an LED 4 is arranged as an auxiliary light source. The LED 4 is a surface-mounted blue light-emitting diode, and is mounted on an LED lighting circuit 5 (first lighting circuit) having an element such as a resistor on a circuit board. Here, “disposing the LED 4 in the vicinity of the glass bulb 31” means that the LED 4 is arranged at a position where the glass bulb 31 can be irradiated, but preferably within 30 mm from the boundary of the external electrode 32a or 32b. It is desirable to arrange the LED 4 so as to irradiate the glass bulb 31 within 2 mm. Thus, by irradiating the glass bulb 31 near the external electrode 32a or 32b with the LED 4, it becomes possible to reliably start the dark with a small light output (for example, the glass illuminance is about 1 lux). Can be reduced. The LED 4 and the LED lighting circuit 5 are provided with insulation measures such as maintaining a sufficient distance from the lamp so that the LED 4 and the LED lighting circuit 5 are not destroyed by a high voltage when the discharge lamp is lit.

  Further, side covers 6 a and 6 b made of, for example, white plastic are arranged along the external electrodes 32 a and 32 b of the respective discharge lamps 3 in the back case 1 b. The side covers 6a and 6b are formed with inclined portions 6a1 and 6b1 having holes through which the respective discharge lamps 3 can be inserted. The inclined portions 6a1 and 6b1 are positioned so as to straddle the vicinity of the boundary between the external electrodes 32a and 32b. That is, since the inclined portions 6a1 and 6b1 can shield most of the external electrodes 32a and 32b, which are non-light emitting portions, from the opening 1a1 during lighting, luminance unevenness can be suppressed. In addition, by setting the inclined portions 6a1 and 6b1 to an inclination angle of 20 ° to 70 °, the light reflection efficiency can be increased, and luminance unevenness can be suppressed.

  A diffusion plate 7 is disposed in the opening of the back case 1b. In addition to the diffusion plate 7, one or a plurality of optical sheets such as a diffusion sheet and a prism sheet can be used depending on the purpose.

  On the back side of the bottom of the back case 1b, a discharge lamp lighting circuit 8 (second lighting circuit) is disposed and electrically connected to each discharge lamp 3. The discharge lamp lighting circuit 8 is a general circuit in which elements such as a transformer, a capacitor, and a resistor are assembled on a circuit board. In order to lower the voltage applied to the external electrodes 32a and 32b, a circuit structure with both high voltages is used.

  Here, electrical connection of the display device of this embodiment will be described with reference to a circuit diagram of FIG.

  The display device is supplied with power by, for example, a household AC100V AC power supply ACPS. A power switch 1011 is connected to the AC power supply ACPS. The on / off operation of the power switch 1011 switches the conduction state on the output side. On the side that is on when the power switch 1011 is turned on, the discharge lamp lighting circuit is connected via the power circuit PSC1 for adjusting to a desired voltage or the like. 8 and a plurality of discharge lamps 3 are connected in parallel. On the other hand, the LED lighting circuit 5 and further the LED 4 are connected to the conducting side when the power switch 1011 is turned off via the power circuit PSC2 for adjusting to a desired voltage or the like.

  Next, the operation of the display device of this embodiment will be described with reference to the flowchart of FIG.

  First, when the power switch 1011 is off, the discharge lamp lighting circuit 8 is not driven, and the discharge lamp 3 is off. On the other hand, the LED lighting circuit 5 is driven, and the LED 4 is kept in the lighting state. In other words, even when the display device is in a standby state, the area irradiated by the LED 4 is not a dark space, and the discharge lamp 3 receiving light from the LED 4 continues to be charged with initial electrons.

  When the power switch 1011 is turned on, the LED lighting circuit 5 is turned off and the LED 4 is turned off. On the other hand, the discharge lamp lighting circuit 8 is turned on, and the discharge lamp 3 is lit. At that time, since the concentration of the initial electrons is already sufficiently high in the glass bulb 31 irradiated by the LED 4 while the power switch 1011 is off, the discharge lamp 3 is turned on almost at the same time as the discharge lamp lighting circuit 8 is turned on. Can be lit. Further, since the LED 4 is in the off state while the power switch 1011 is in the on state, luminance unevenness due to the light of the LED 4 does not occur on the light emitting surface of the display device in the driving state.

  When the power switch 1011 is turned off, the discharge lamp lighting circuit 8 is turned off and the discharge lamp 3 is not turned off, but the LED lighting circuit 5 is turned on and the LED 4 is turned on.

  By performing such a lighting cycle in conjunction with the power switch 1011, the circuit of the LED lighting circuit 5 that controls the lighting / extinguishing of the LED 4 can be simplified. That is, since the on / off operation of the power switch 1011 is performed by the user, the turning on / off of the LED 4 is the same as that performed by the user, and no timer or detection circuit for turning off the LED 4 is required. It is possible to prevent the circuit from becoming complicated, large and costly.

  Further, since the LED 4 is turned off while the discharge lamp 3 is lit, it is possible to prevent the heat from the discharge lamp 3 from being transmitted and the temperature of the LED 4 to rise excessively, resulting in a short life. Further, although the LED 4 is lit even when the display device is in a standby state, since the amount of power consumed by the LED 4 is negligible, an increase in power is not a problem.

  Therefore, in the first embodiment, the LED lighting circuit 5 and the discharge lamp lighting circuit 8 are electrically connected to the power switch 1011 that can turn on and off the input from the AC power source ACPS. When turned on, the LED lighting circuit 5 is turned off and the LED 4 is turned off, and the discharge lamp lighting circuit 8 is turned on and the discharge lamp 3 is turned on. When the power switch 1011 is turned off, the LED lighting circuit 5 is turned off. Is turned on and the LED 4 is turned on, and the discharge lamp lighting circuit 8 is turned off and the discharge lamp 3 is turned off, so that the discharge lamp 3 is irradiated with light before the discharge lamp 3 is turned on. Since the initial electrons are always charged, not in the dark state, it can be turned on instantaneously, providing a display device with excellent dark start characteristics Kill. Further, since the LED 4 is not lit while the discharge lamp 3 is lit, it is possible to prevent the light of the LED 4 from appearing on the light emitting surface to cause uneven brightness, and the lit LED 4 is heated by the heat of the discharge lamp 3. It is possible to prevent a short life from rising.

  Further, the on / off operation of the LED 4 is performed by the on / off operation of the power switch 1011 of the display device of the user, so that the LED lighting circuit 5 can be prevented from being complicated, enlarged, and cost increased. Furthermore, by arranging the LED 4 on the glass bulb 31 in the vicinity of the electrode 32a of the discharge lamp 3, it is possible to perform a reliable dark start even with a small light output, and the power consumption of the LED 4 can be reduced. Can be realized.

(Second Embodiment)
FIG. 6 is a cross-sectional view for explaining a display device according to a second embodiment of the present invention. About each part of this 2nd Embodiment, the part same as each part of the display apparatus of 1st Embodiment of FIG. 3 is shown with the same code | symbol, and the description is abbreviate | omitted.

  In this embodiment, the inclined portions 6a1 and 6b1 are positioned so as to cover a part of the external electrodes 32a and 32b and the glass bulb 31, and the LEDs 4 are arranged in the vicinity of the glass bulb 31 on the external electrode 32a side. That is, LED4 is the state arrange | positioned in the side cover 6a. Therefore, a wide range in the side cover 6a can be filled with the light of the LED 4, and when the power switch 1011 is turned off, initial electrons can be supplied to many discharge lamps 3, and more stable dark start characteristics can be obtained. In addition, since the light of LED4 stays in the side cover 6a and does not appear on the light emitting surface of the display device, it is possible to adopt a form in which the LED4 is always lit.

  Therefore, in the first embodiment, the inclined portions 6a1 and 6b1 are positioned so as to cover a part of the external electrodes 32a and 32b and the glass bulb 31, and the LED 4 is disposed in the vicinity of the glass bulb 31, thereby It is possible to realize a dark starting characteristic superior to that of the embodiment.

  The embodiment of the present invention is not limited to the above, and may be modified as follows, for example.

  In the present embodiment, an external electrode discharge lamp is used as the discharge lamp 3, but a cold cathode discharge lamp, a hot cathode discharge lamp, or the like may be used, and there is no limitation on the type, shape, size, and the like.

  The LED 4 is not limited to a blue surface-mounted LED. That is, a bullet-type LED may be used, and the emission color may be white or green. Moreover, you may use UV-LED. Further, a plurality of LEDs 4 may be arranged as desired.

  Regarding the arrangement of the LEDs 4, when one of the external electrodes 32a and 32b of the discharge lamp 3 is lit at a high pressure and the other at a low pressure (for example, ground), the LED 4 needs to be arranged on the high pressure side. In the second embodiment, the LED 4 may be attached to the inside of the side covers 6a and 6b, for example, the inclined portions 6a1 and 6b1. Alternatively, a hole for entering the LED may be formed in the back case 1b, and the discharge lamp 3 may be irradiated with light from the hole.

  Further, the LED 4 is not necessarily mounted on the LED lighting circuit 5. Further, the LED lighting circuit 5 may not be formed on the substrate, and may be one in which a resistor is connected in series in the middle of the harness connecting the LEDs 4. Further, the LED lighting circuit 5 and the discharge lamp lighting circuit 8 may be formed on one substrate.

  The switching means is not limited to the power switch 1011 attached to the display device, and may be, for example, a power switch of a remote controller for operating on / off of the liquid crystal television. This also includes means that can be equated.

The figure for demonstrating the display apparatus of the 1st Embodiment of this invention. The figure for demonstrating a backlight. The figure for demonstrating the cross section of the arrow direction of A-A 'of FIG. FIG. 6 is a circuit diagram for explaining electrical connection of the display device of this embodiment. FIG. 10 is a flowchart for explaining an operation of the display device of this embodiment; Sectional drawing for demonstrating the display apparatus of the 2nd Embodiment of this invention.

Explanation of symbols

101 Front frame 1011 Power switch 102 Back frame 103 Liquid crystal panel 104 Backlight 1a Front case 1b Back case 3 Discharge lamp 31 Glass bulbs 32a and 32b External electrode 4 LED
5 LED lighting circuit 6a, 6b Side cover 8 Discharge lamp lighting circuit

Claims (1)

A housing, wherein arranged in the inner housing, and the external electrode discharge lamp with external electrodes on both ends of the discharge vessel, an auxiliary light source disposed in the vicinity of the discharge vessel, a main power supply and electrically connected A power switch that can be turned on or off by a user, an input side electrically connected to an off side of the power switch, and an output side electrically connected to the auxiliary light source And the input side is electrically connected to the ON side of the power switch, and the output side includes a second lighting circuit electrically connected to the external electrode discharge lamp ,
When the user turns on the power switch, the second lighting circuit is turned on and the external electrode discharge lamp is turned on, and the first lighting circuit is turned off and the external electrode discharge is turned on. The auxiliary light source that was on until just before the lamp is turned off,
When the user turns off the power switch, the second lighting circuit is turned off and the external electrode discharge lamp is turned off, and the first lighting circuit is turned on and the auxiliary light source is turned on. A display device characterized by being lit.

Images