JP4158430B2 - High pressure discharge lamp device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-pressure discharge lamp device that heats an arc tube with a heater when starting the lamp.
[0002]
[Prior art]
Backlights such as liquid crystal projectors and projection-type liquid crystal display devices are required to project an image uniformly with sufficient luminance, efficiency and color rendering on a rectangular screen. A high-pressure discharge lamp in which mercury or a metal halide is enclosed in the light emitting portion of the arc tube is used. In recent years, it has been required to further promote downsizing of light sources and point light sources.
[0003]
In view of these requirements, instead of a high-pressure discharge lamp enclosing a metal halide, an ultrahigh-pressure mercury lamp in which mercury of 0.15 mg / mm ³ or more is enclosed and the mercury vapor pressure at the time of stable lighting of the lamp exceeds 100 atm. Have been proposed (JP-A-2-148561, JP-A-6-52830).
[0004]
In order to achieve high brightness, high efficiency, and high color rendering, this type of lamp improves the light output by suppressing the radial expansion of the arc by increasing the mercury vapor pressure during stable lighting to 100 atm or higher. The arc tube seal portion is a so-called sealed type without exhaust exhaust tubes to enhance pressure resistance, and the thickness of the light emission portion is used for automobile headlamps, etc. It is about 2 mm, which is about three times that of the high-pressure discharge lamp used.
[0005]
Since the light emitting part of the arc tube with such a large thickness has a large heat capacity and is difficult to warm, the liquid mercury accumulated in the form of droplets on the inner surface of the light emitting part at the start of lighting of the lamp is heated to become mercury vapor. A considerable time is required until the vapor partial pressure rises and the light output of the lamp rises. For example, a lamp of about 150 W requires about 60 seconds.
[0006]
For this reason, liquid crystal projectors and projection type liquid crystal display devices that use this type of lamp as a backlight start up slowly, so that when these devices are used for presentations, etc., the screen reaches sufficient brightness to project an image. There was a problem that waiting time was long.
[0007]
In order to improve the delay of the rise, a means for heating the surface temperature of the light emitting part to 100 ° C. or higher in advance before starting the lamp is proposed by a heater in which a heating wire is wound around the seal part of the arc tube is proposed. (Japanese Patent Laid-Open No. 2001-266797).
[0008]
[Problems to be solved by the invention]

However, the lamp does not know when it will start lighting, so if you try to preheat the light emitting part of the arc tube before starting lighting, make sure that the heater that preheats is always energized even when the lamp is not lit. Therefore, there is a problem that power consumption is significantly increased. In addition, even if a portable display device called a mobile system has a heater in a light-emitting tube of a lamp serving as a backlight, when carrying the device, the heater is energized and the light-emitting part of the light-emitting tube is energized. Since the lamp cannot be preheated, the rise of the light output of the lamp is delayed when it is carried and used immediately.
[0009]
In view of such circumstances, the present inventors do not preheat the light emitting portion of the arc tube with the heater before starting the lamp lighting, and start energizing the heater at or after starting the lamp lighting. An experiment was carried out to increase the amount of current supplied to the heater in an attempt to speed up the rise of the output. As a result, the lamp life became shorter than usual, and the light emitting part swelled early and stabilized. The lamp voltage at the time of lighting decreased remarkably or caused many explosions.
[0010]
And the cause is that the surface temperature of the light emitting part rises abnormally due to the heat dissipation of the heater and the heat generated by the lamp discharge, the inner surface of the light emitting part becomes cristobalite and devitrifies early, and the devitrified part is The heat generated by the discharge of the lamp is shut off and confined in the light emitting part. As a result, the surface temperature of the light emitting part is further increased to cause the light emitting part to swell, and the content of the light emitting part is equivalent to the amount of the swelling. It has been found that the lamp voltage is significantly reduced by increasing the product and causing a sharp decrease in mercury density.
[0011]
Therefore, an appropriate energization amount and energization time of the heater that can quickly heat the light emitting portion of the arc tube at a temperature substantially equal to the ambient temperature at the time of starting lighting the lamp without causing the above-mentioned problems were obtained through experiments. According to the energization time, when the lamp that was lit was turned off and restarted immediately, the light-emitting part that was hotter than the ambient temperature due to residual heat would remain in the energization amount even after the light output of the lamp started up. Since it is heated by a large heater, its surface temperature may rise abnormally and swell immediately, or may burst.
[0012]
In addition, if the time for energizing the heater is increased, there is a problem that the damage to the heater increases correspondingly and the durability life is shortened.
[0013]
In view of this, the present invention increases the light output at the same level as or more than when the arc tube is preheated with the heater before starting the lighting, even if the arc tube starts to be heated with the heater at the start of lighting of the high pressure discharge lamp or after the start. In addition to being able to speed up, the light emitting part of the arc tube heated by the heater bulges so that problems such as a decrease in lamp voltage during stable lighting and a shortened lamp life can be solved. This is a technical issue.
[0014]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention controls the amount of current supplied to the heater according to the discharge voltage between the heater that heats the light emitting portion of the arc tube and the main electrode of the lamp when starting the lamp. in high-pressure discharge lamp apparatus energizing controller is provided, wherein the energization controller is a switch means for starting and stopping the energization of the heater, the discharge voltage between the main electrodes of the lamp voltage during stable lighting from 30 to 55 Electricity that starts energizing the heater when it is within% and maximizes the energization amount for a few seconds at the beginning of lighting, and stops energization when it exceeds 55 to 65% of the lamp voltage during stable lighting And a control means .
[0015]
The high-pressure discharge lamp device according to the present invention starts energization to the heater that heats the light emitting portion of the arc tube when the discharge voltage between the main electrodes of the lamp is within 30 to 55% of the lamp voltage during stable lighting. The amount of electricity is maximized only for a few seconds at the beginning of lighting, and when the discharge voltage between the main electrodes of the lamp exceeds 55 to 65% of the lamp voltage during stable lighting, the heater is turned off to emit light. It is possible to quickly heat the light emitting part of the tube to a high temperature to increase the rising speed of light output, and at the same time, it is possible to prevent the surface temperature of the light emitting part from rising abnormally and causing the light emitting part to expand or rupture. In particular, even when the surface temperature of the light emitting part is higher than the ambient temperature due to the residual heat during lighting when the lamp that has been turned off is restarted, the light emitting part is heated to an unnecessarily high temperature and the light emitting part expands. Broke It is possible to prevent that.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a diagram showing an example of a high-pressure discharge lamp device according to the present invention, FIG. 2 is a graph showing an example of its rising characteristics, and FIG. 3 is a flowchart showing an example of a control procedure of an energization controller.
[0017]
In the high-pressure discharge lamp device of this example, a heater 4 that heats the light-emitting portion 3 and accelerates the rise of light output is provided on the arc tube 2 of an ultra-high pressure mercury lamp 1 of 150 W, for example. The light emitting unit 3 has an internal volume of about 60 mm ^3, and a pair of main electrodes embedded and fixed in seal portions 5R and 5L for sealing both ends of the light emitting unit 3 are provided therein. While being provided to face each other, about 20 kPa (at room temperature) of argon, which is an auxiliary gas for starting lighting, and about 12 mg of mercury are enclosed.
[0018]
The heater 4 is composed of a heating wire having a wire diameter of about 0.29 mm and a length of 170 mm mainly composed of iron, nickel, chromium, aluminum, and the like. The heating wire extends from one seal portion 5R to the light emitting portion 3 and the other. The outer surface of the arc tube 2 is spirally wound so as to reach the seal portion 5L, and the sides close to the light-emitting portion 3 of the seal portions 5R and 5L are respectively tightly wound so that 15V-3. When 6 A of electric power is supplied, the heater is 54 W designed to reach a temperature of about 1000 ° C. in a few seconds in the outside air.
[0019]
In the figure, reference numeral 7 denotes a lamp lighting device connected between the electrode terminals 8R, 8L of the lamp 1 and the lamp power source 9, and the lighting device 7 gives electrical conditions necessary for starting the lamp 1 to be lit. In addition to the starter 10 and the ballast 11 that controls the lamp current to a specified value, a voltage detector 12 that detects the voltage between the main electrodes of the lamp 1 and outputs a detection signal thereof is provided. The lamp power supply 9 also serves as a power supply for the heater 4.
[0020]
In the figure, reference numeral 13 denotes an energization controller that controls the energization amount to the heater 4 in accordance with the voltage between the main electrodes of the lamp 1. The energization controller is activated when the lamp power source 9 is turned on, for example. Switch means 14 for starting and stopping in step S3, and power control means 15 for changing the energization amount to the heater 4 stepwise or continuously, and energization of the heater 4 is started when the lamp 1 is turned on or after starting. When the voltage between the main electrodes at the beginning of lighting of the lamp 1 is lower than the lamp voltage at the time of stable lighting, the energizing amount to the heater 4 is maximized for a certain time, and then the energizing amount is stepwise or continuous. It is constituted so that it may be lowered or immediately energized.
[0021]
In the figure, reference numeral 16 denotes a hard glass reflecting mirror made of borosilicate coated with an inner surface of a dielectric multilayer film that reflects visible light and does not reflect infrared light. A front glass 17 having a non-reflective coating is attached to the front opening.
[0022]
Hereinafter, the difference between the case where the energization amount to the heater 4 is appropriately controlled according to the voltage between the main electrodes of the lamp 1 and the case where it is not controlled will be described.
[0023]
For example, if the current value to be supplied to the heater 4 at the start of lighting of the lamp 1 is set to 3.6A as a design value, and the current of 3.6A is continuously supplied to the heater 4 until the lamp 1 is in a stable lighting state, the arc tube 2 There is a risk that the surface temperature will rise abnormally, causing the light-emitting portion 3 to swell and the lamp voltage during stable lighting to decrease.
[0024]
On the other hand, when the voltage between the main electrodes at the start of lighting of the lamp 1 is lower than the lamp voltage at the time of stable lighting, that is, before reaching the voltage value corresponding to 100% of the lamp voltage, the energization controller 13 If the energization amount to 4 is set to the design value of 3.6 A for a predetermined time and then the energization is stopped immediately or the energization is stopped after the energization amount is reduced to 3.6 A or less, the light emitting unit 3 The risk of swelling or bursting is reduced.
[0025]
Further, the energization amount to the heater 4 controlled by the energization controller 13 is not limited to the case where the design value 3.6A is maximized, and the maximum value may exceed the design value 3.6A. For example, the graph of FIG. 2 is designed for the heater 4 by the power control means 15 of the energization controller 13 when the voltage between the main electrodes at the beginning of lamp lighting is within 55% of the lamp voltage during stable lighting. After passing a maximum current of 7.0 A, which greatly exceeds the value of 3.6 A, for 3 seconds, the energization amount is reduced to the design value of 3.6 A, and the voltage between the main electrodes detected by the voltage detector 12 is reduced. The graph shows the rise characteristics when the energization of the heater 4 is stopped by the switch means 14 of the energization controller 13 when the lamp voltage reaches 65% during stable lighting. Even after the voltage between the main electrodes reaches 100% of the lamp voltage, the surface temperature of the arc tube 2 rises, but since the rise is relatively small, the light emitting portion 3 swells and the lamp voltage during stable lighting is reduced. There is no fear that it will decrease or the lamp life will be shortened.
[0026]
In addition, the amount of energization to the heater 4 after the energization of the heater 4 at the start of lighting of the lamp 1 until the voltage between the main electrodes of the lamp 1 reaches 65% of the lamp voltage at the time of stable lighting. According to the comparison experiment between the case where the design value is set to 3.6A and the case where the design value is set to 7.0A which exceeds the design value for the first 3 seconds and then is reduced to the design value of 3.6A. In the former, the average time required to obtain a brightness equivalent to about one half of the brightness when the lamp is stably lit is about 25 seconds, whereas in the latter, it is only about 15 seconds. It was confirmed that the rising speed of the light output was remarkably increased. The average required time when the maximum current of 8.5 A was passed for 2 seconds at the start of energization of the heater 4 and then reduced to the design value of 3.6 A was about 14 seconds.
[0027]
In addition, when the voltage between the main electrodes at the beginning of lighting start of the lamp 1 is within 100% of the lamp voltage at the time of stable lighting, the heater 4 has a value of 7.0A to 8.5A which greatly exceeds the designed value 3.6A. It has been confirmed by experiments that even if the maximum current is applied, the lamp life is less likely to be lost due to overheating of the light emitting section 3 and the damage to the heater 4 can be reduced for only a few seconds.
[0028]
Hereinafter, an example of the control procedure by the energization controller 13 will be described with reference to the flowchart of FIG. First, in step (1), it is determined whether or not the lamp power supply 9 is turned on. When the lamp power supply 9 is turned on, the process proceeds to step (2), and the switch means 14 for starting energization of the heater 4 is set. It is turned on and a maximum current of, for example, 7.0 A is supplied to the heater 4 almost simultaneously with the start of lighting of the lamp 1.
[0029]
Next, the process proceeds to step (3), and it is determined whether or not 3 seconds have elapsed. When 3 seconds have elapsed, the process proceeds to step (4) and the power control means 15 for varying the energization amount to the heater 4. The current supplied to the heater 4 is reduced from 7.0 A to the designed value of 3.6 A.
[0030]
Then, the process proceeds to step (5), where it is determined whether or not the voltage between the main electrodes of the lamp 1 detected by the voltage detector 12 has reached 65% of the lamp voltage during stable lighting. When it reaches, step (6) is proceeded to, the switch means 14 is turned off, and the energization to the heater 4 is stopped.
[0031]
In this way, if energization control of the heater 4 is performed in accordance with the voltage between the main electrodes at the beginning of lighting of the lamp 1, the light emitting portion 3 of the arc tube 2 is not preheated by the heater 4 before the lighting of the lamp 1 is started. Even if heating by the heater 4 is started at the same time as the start of lighting or after the start, the light output can be raised at a speed equivalent to or higher than that in the case of preheating, and at the same time, the light emitting unit 3 is heated by the heat of the heater 4. The risk of bulging or rupturing is also eliminated.
[0032]
The operation of the energization controller 13 is not limited to the above. For example, at the same time as starting the lamp 1 in a state where the temperature of the arc tube 2 is substantially equal to the ambient temperature, a current of 7.0 A is supplied to the heater 4 for 3 seconds, Thereafter, the time required for the voltage between the main electrodes of the lamp 1 to reach 65% of the lamp voltage at the time of stable lighting is measured in advance by experiment, and the required time has elapsed. Alternatively, the energization of the heater 4 may be stopped by a timer.
[0033]
Further, the voltage between the main electrodes at the beginning of lighting start of the lamp 1 is detected in real time by the voltage detector 12 or the like, and the voltage between the main electrodes is within 30 to 55% of the lamp voltage at the time of stable lighting, for example. When the energization of the heater 4 is started and the control is performed to stop the energization immediately when the lamp voltage exceeds 55 to 65%, the arc tube 2 is used when the lamp 1 once turned off is restarted. When the surface temperature of the lamp is higher than the ambient temperature due to the residual heat during lighting, the amount of current supplied to the heater 4 is reduced to prevent the light emitting portion 3 of the arc tube 2 from being heated to an unnecessarily high temperature. be able to.
[0034]
【The invention's effect】
As described above, according to the present invention, the light emitting portion of the arc tube can be started to be heated by the heater at the time of starting the lighting of the lamp or after the starting, so that the rising speed of the light output of the lamp can be increased and the heater is heated. There is an effect that it is possible to prevent the temperature of the light emitting portion from rising abnormally and causing the light emitting portion to bulge or to burst, thereby impairing the lamp life. In addition, since it is not necessary to preheat a lamp that does not know when to start lighting with the heater before starting lighting, there is also an effect that the power consumption of the heater can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a high-pressure discharge lamp device according to the present invention. FIG. 2 is a graph showing rising characteristics of the high-pressure discharge lamp device according to the present invention. FIG. 3 is a flowchart showing a control procedure of an energization controller constituting the present invention. [Explanation of symbols]
1 ……………… Lamp 2 ……………… Luminescent tube 3 ……………… Light emitting part 4 ……………… Heater 9 ……………… Lamp power supply 12 ……………… Voltage detector 13 ……………… Energizing controller 14 ……………… Switch means 15 ……………… Power control means

Claims (2)

In a high pressure discharge lamp apparatus provided with a heater for heating a light emitting portion of an arc tube when starting the lamp, and an energization controller for controlling an energization amount to the heater according to a discharge voltage between the main electrodes of the lamp When the energization controller (13) has a switch means (14) for starting and stopping energization of the heater and the discharge voltage between the main electrodes is within 30 to 55% of the lamp voltage during stable lighting. Power control means (15) for starting energization of the heater, maximizing the energization amount only for a few seconds at the start of lighting, and stopping energization when exceeding 55 to 65% of the lamp voltage during stable lighting; High pressure discharge lamp device characterized by having The high-pressure discharge lamp device according to claim 1, wherein the heater is a heating wire wound around the outer surface of the arc tube.

Images