JP4257359B2 - Light source with temperature detection compound wire - Google Patents

Description

  The present invention relates to a temperature detection composite wire that detects an abnormal temperature of a discharge lamp.

  When the temperature of the discharge lamp rises due to abnormal discharge, the discharge lamp may become so hot that the glass melts. In order to avoid this danger, thermal fuses are installed in the valve inside the base and near the electrodes. A thermal fuse is a component that protects against overheating. The thermal fuse is connected in series with the discharge lamp and detects an increase in the temperature of the discharge lamp. When the temperature of the discharge lamp reaches a predetermined temperature (hereinafter referred to as “abnormal temperature”), the fusible body in the thermal fuse is melted and the connection with the discharge lamp is cut off. Thereby, supply of electric power to the discharge lamp is stopped.

  However, there are various sizes of discharge lamps. If the size of the discharge lamp is small, it is not possible to secure a sufficient place for installing the thermal fuse. In that case, the temperature fuse and the discharge lamp could not be connected in series, and the abnormality of the discharge lamp could not be detected.

  On the other hand, Patent Document 1 discloses a technique for detecting an abnormality in a discharge lamp regardless of the size of the discharge lamp.

  FIG. 5 is a schematic diagram showing a high temperature detection line 11 for detecting an abnormal temperature using the melting disclosed in Patent Document 1. As shown in FIG. The high temperature detection line 11 is a line that detects a high temperature, and is used, for example, to detect the occurrence of heating or fire. As an example, the high-temperature detection line 11 of Patent Document 1 is burned with a flame of a gas burner (not shown).

  The high temperature detection line 11 includes a center conductor 14, an insulator 15, an outer conductor 17, and an outer skin 19. An insulator 15 made of thermoplastic resin covers the center conductor 14, and an outer conductor 17 covers the insulator 15. The outer skin 19 covers the outside of the outer conductor 17.

When the high temperature detection line 11 is exposed to a high temperature flame, the insulator 15 is melted, and the center conductor 14 and the outer conductor 15 are short-circuited to notify that the temperature is high.
JP-A-8-212838

  However, since there are plastic appliances in the discharge lamp, it is necessary to detect abnormal heat generation without delay in time, and if detection takes time, the appliance melts or the appliance is severely damaged. When the abnormal temperature detection of the discharge lamp is used for the high temperature detection line 11 of Patent Document 1, even if the temperature of the discharge lamp reaches an abnormal temperature (150 ° C. to 200 ° C.), the insulator 15 Since it is covered with the outer skin 19, heat may not be transmitted immediately, and it may take time to dissolve. As a result, a short circuit between the center conductor 11 and the outer conductor 17 also takes time, and the abnormal temperature of the discharge lamp could not be detected quickly.

  An object of the present invention is to provide a composite wire that can quickly detect an abnormal temperature of a discharge lamp.

In order to achieve the above object, a light source of the present invention is a light source including a temperature detection composite line for detecting an abnormal temperature, and includes a plurality of discharge lamps that emit light at a desired brightness, A current line through which a current for detecting a temperature abnormality flows, a detection line that enables detection of a temperature abnormality of the discharge lamp by flowing a current in contact with the current line, and while exposing itself to the outside A plurality of temperature detectors , each comprising a current line and an insulator that insulates the detection line, and melts when the insulator reaches a predetermined temperature due to heat from the discharge lamp to short-circuit the current line and the detection line Each of the plurality of temperature detection compound lines is wound around each of the discharge lamps, and the plurality of temperature detection composite lines are connected in series .

  According to the present invention, when the temperature of the discharge lamp rises due to abnormal discharge and reaches a predetermined temperature of the insulator, the insulator is melted and the current line and the detection line are short-circuited. The temperature detection composite wire does not have an outer skin or the like that blocks heat conduction to the insulator, and when the temperature of the discharge lamp reaches a predetermined temperature, the temperature detection composite wire can immediately transmit heat. . Thereby, the temperature detection composite wire can quickly detect an abnormal temperature without requiring time for melting or short-circuiting.

  The insulator may cover the current line so that the current line is not exposed to the outside. According to this, dust and dust do not accumulate, and the risk of leakage can be reduced.

  The detection line may be spirally wound around the insulator covering the current line.

  According to this, even if the detection line moves in any direction when the insulator is melted, it can be short-circuited with the current line.

  According to the present invention, an abnormal temperature of a discharge lamp can be detected quickly.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a discharge lamp 1 in the present embodiment. The discharge lamp 1 has a bulb 2 and a composite wire 3.

  The discharge lamp 1 is a lamp that emits light using rare gas discharge, and is, for example, a cold cathode lamp or a hot cathode lamp. Cold cathode lamps are used as backlights for liquid crystal televisions, and hot cathode lamps are used as fluorescent lamps. The discharge lamp 1 has a bulb 2, and a composite wire 3 is wound on the surface of the bulb 2. The normal temperature of the valve 2 is approximately 70 ° C.

  The bulb 2 is a container hermetically sealed with glass, and a phosphor is applied inside. In the case of a cold cathode lamp, borosilicate glass is used for the bulb 2, and in the case of a hot cathode lamp, soda glass is used for the bulb 2. In addition, a rare gas and a small amount of mercury are enclosed in the valve 2. The rare gas is, for example, argon or neon.

  When a high voltage is applied between electrodes (not shown) using nickel, discharge occurs in the bulb 2 and electrons are emitted. When the emitted electrons collide with mercury atoms or rare gas atoms in the bulb 2, the colliding atoms are excited. When atoms are excited, ultraviolet rays are generated. When the generated ultraviolet rays are irradiated on the phosphor, visible light is emitted.

  In such a normal light emission state, the temperature of the bulb 2 is about 70 ° C. as described above. However, when an abnormal state occurs due to deterioration of the ballast or the like, the temperature of the valve 2 becomes 150 ° C. to 200 ° C. as described above.

  The composite wire 3 is wound at a position where the temperature of the valve 2 can be detected, and detects the temperature of the valve 2.

  FIG. 2A is a schematic diagram showing a state of the composite wire 3 when the inside of the valve 2 in this embodiment is at a normal temperature. FIG. 2B is a schematic diagram showing a state of the composite wire 3 when the inside of the valve 2 in this embodiment is at an abnormal temperature.

  First, the configuration of the composite wire 3 will be described in detail with reference to FIG. 2A. The composite wire 3 has an insulator 4, a current wire 5, and a detection wire 6.

  The insulator 4 is made of a thermoplastic resin material having a melting point that is higher than the normal temperature of the valve 2, and is, for example, nylon. The melting point of nylon is about 150 ° C to 180 ° C. The insulator 4 insulates the current line 5 and the detection line 6 from each other. The insulator 4 covers the current line 5 so that the current line 5 is not exposed to the outside. According to this, dust and dust do not accumulate, and the risk of leakage can be reduced.

  The current line 5 is covered with an insulator 4 so as not to be short-circuited with the detection line 6. A very small amount of current flows through the current line 5.

  The detection wire 6 is spirally wound around the insulator 4 so as to short-circuit with the current wire 5 when the insulator 4 is dissolved. According to this, when the insulator 4 is melted, the detection line 6 can be short-circuited with the current line 5 in any direction.

  Next, the state change of the composite wire 3 will be described in detail with reference to FIGS. 2A and 2B. Referring to FIG. 2A, the insulator 4 insulates the current line 5 and the detection line 6 from each other. When the temperature of the valve 2 is a normal temperature, the current flowing through the current line 5 does not flow through the detection line 6. When abnormal discharge occurs and the temperature of the bulb 2 rises and reaches the melting point of the insulator 4, the insulator 4 is dissolved, and the current line 5 and the detection line 6 are short-circuited as shown in FIG. 2B.

  Referring to FIG. 2B, a part of the insulator 4 is melted and the current line 5 and the detection line 6 are short-circuited. A very small amount of current flows through the current line 5, and a very small amount of current flows into the detection line 6 from the short-circuited portion. The detection line 6 can detect an abnormality of the discharge lamp 1 by the flowing current.

  FIG. 3A is a diagram illustrating an example in which power is supplied from the power source to the discharge lamp 1. FIG. 3B is a diagram showing an example in which power supply from the power source to the discharge lamp 1 is cut off.

  First, the configuration of the embodiment will be described in detail with reference to FIG. 3A. The light source has a discharge lamp 1, a current line 5, a detection line 6, an inverter 7, a current fuse 8, and grounds 9 and 10.

  The inverter 7 converts DC power supplied from an inverter power supply (not shown) into AC power and supplies it to the discharge lamp 1.

  The current fuse 8 has an internal resistance and a fusible body. The internal resistance of the current fuse 8 generates heat when a current flows from the detection line 6. The fusible body of the current fuse 8 melts when the heat generated by the internal resistance reaches a desired temperature.

  Next, the state change of the embodiment will be described in detail with reference to FIGS. 3A and 3B. Referring to FIG. 3A, when the discharge lamp 1 is at a normal temperature, the current fuse 8 connects the inverter power supply and the inverter 7, and power from the inverter power supply is supplied to the inverter 7 via the current fuse 8. . When the temperature of the bulb 2 rises due to abnormal discharge and reaches the melting point of the insulator 4, the insulator 4 is dissolved.

  Referring to FIG. 3B, the fusible body is dissolved and the circuit is interrupted. When the insulator 4 is melted, the current line 5 and the detection line 6 are short-circuited, and the current flowing in the current line 5 flows from the location where the current is short-circuited to the detection line 6. And the heat | fever generate | occur | produces with the internal resistance of the current fuse 8 with the electric current from the detection line 6, and the fusible body of the current fuse 8 is blown out with the heat. Thereby, the power supply from the inverter power supply to the inverter 7 is cut off.

  FIG. 4 is a flowchart showing a change in state when the valve 2 in the present embodiment reaches an abnormal temperature. A very small amount of current flows through the current line 5. Further, when the bulb 2 is at a normal temperature, the insulator 4 insulates the current line 5 from the detection line 6, and power is supplied from the inverter power supply to the discharge lamp 1.

  When the temperature of the valve 2 rises and reaches the melting point of the insulator 4, the insulator 4 is dissolved (step 50). When the insulator 4 is dissolved, the current line 5 and the detection line 6 are short-circuited, and the current flowing through the current line 5 flows from the short-circuited position to the detection line 6 (step 51). The current flowing through the detection line 6 flows into the current fuse 8, and the internal resistance of the current fuse 8 is overheated (step 52). When the internal resistance is heated, the fusible body in the current fuse 8 is melted (step 53). When the fusible body melts, the power supply from the inverter power supply is cut off (step 54).

  As described above, according to the present embodiment, the insulator 4 is a thermoplastic resin having a melting point that is higher than the normal temperature of the discharge lamp 1, and is exposed so that the external temperature is directly transmitted. The composite wire 3 is wound around the valve 2 so that the temperature of the valve 2 is easily transmitted to the insulator 4. Therefore, when the temperature of the bulb 2 rises due to abnormal discharge and reaches the melting point of the insulator 4, the temperature of the bulb 2 is immediately transmitted to the insulator 4, and the insulator 4 is melted and the current line 5, the detection line 6, Is short-circuited, and abnormality of the valve 2 can be detected quickly.

  The discharge lamp 1 is connected to a circuit that controls the supply of power. If the temperature of the bulb 2 is normal, power is supplied from the inverter power supply to the discharge lamp 1, and if the temperature of the bulb 2 is abnormal, supply of power from the inverter power supply to the discharge lamp 1 is cut off. As a result, it is possible to avoid the risk of fire due to the supply of power from the inverter power supply at an abnormal temperature.

  In the case of a backlight for a liquid crystal in which a plurality of light sources are arranged, the power supply to all the light sources can be stopped when an abnormal temperature occurs in the backlight by connecting the composite wires 3 arranged in each light source in series. . As a result, a plurality of light sources can be detected more easily than in the case where a thermal fuse is mounted on each light source.

It is a schematic diagram of the discharge lamp 1 in this embodiment. It is a schematic diagram which shows the state of the composite wire 3 when the inside of the valve | bulb 2 in this embodiment is normal temperature. It is a schematic diagram which shows the state of the composite wire 3 when the inside of the valve | bulb 2 in this embodiment is abnormal temperature. It is a figure which shows the example which supplies electric power to the discharge lamp 1 from a power supply. It is a figure which shows the example which has interrupted supply of electric power from the power supply to the discharge lamp. It is a flowchart which shows the change of a state when the valve | bulb 2 in this embodiment becomes abnormal temperature. It is a schematic diagram which shows the conventional high temperature detection line for detecting abnormal temperature using melt | dissolution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Bulb 3 Compound line 4 Insulator 5 Current line 6 Sense line 7 Inverter 8 Current fuse 9, 10 Ground 11 High temperature detection line 14 Center conductor 15 Insulator 17 Outer conductor 19 Outer skin 50-54 step

Claims (1)

A light source comprising a temperature detection composite wire for detecting an abnormal temperature,
A plurality of discharge lamps that emit light at a desired brightness;
A current line through which a current for detecting a temperature abnormality of the discharge lamp flows, a detection line that enables detection of a temperature abnormality of the discharge lamp by flowing a current in contact with the current line, An insulator that insulates the current line and the detection line while being exposed, and melts when the insulator reaches a predetermined temperature by heat from the discharge lamp, thereby short-circuiting the current line and the detection line . A plurality of temperature detection composite wires,
A light source in which each of the plurality of temperature detection compound lines is wound around each of the discharge lamps, and the plurality of temperature detection composite lines wound are connected in series .

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