JPH0240893A - Discharge lamp lighting apparatus - Google Patents

Abstract

PURPOSE:To lighten a burden of a direct power source E of an electric discharge lamp lighting device by employing a lamp heater as a part of impedance element to restrict a filament current when a filament is preheated. CONSTITUTION:A lamp heater 1 is connected across the anode of a direct power source E and a filament F1, to be installed into preheating roop so as to be employed at least as a part of impedance element to restrict a filament current. A discharge lamp 1 is then heated by the lamp heater 1 simultaneously when the filament F1 and the other filament F2 are preheated. Power consumtion of a resistor Rf for restricting the filament current is thus canceled. The burden of the direct power source E is accordingly lightened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 1 The present invention is used in an optical image reading device, in which a lamp heater is used to heat a discharge lamp so that the amount of light from the lamp increases depending on the imaging element F.
Discharge lamp lighting Vi that speeds up the time to reach the minimum required illuminance of
: It is related to the location.

] Prior Art 1 When a discharge lamp is turned on, the rise of its luminous flux rises as the ambient temperature rises and changes in various ways as shown in the tIfJa diagram.

When a discharge lamp with such characteristics is used in an optical image reading device (PPC, FAX, etc.), immediately after starting at a low temperature, the lamp light intensity does not reach the minimum required illuminance of the image sensor (CCD), and the image Reading may not be possible. Generally, in order to shorten the unusable time such as 1.: (1) When lighting at a low temperature, a current higher than the rated value is passed to increase the absolute light intensity and to speed up the rise of the optical output.

(2) A lamp heater is provided to heat the discharge lamp to raise the lamp temperature.

Measures such as these will be taken. Note that the present invention relates to the case (2) above.

A conventional discharge lamp lighting device of this type is shown in FIG.

In this discharge lamp lighting device, a DC power source E is connected to an inverter IV.
This converts the power into high-frequency power and lights the discharge lamp η at high frequency. The operation of the lamp heater 1, which heats the discharge lamp α and raises the lamp temperature when the discharge lamp e starts, is controlled by a switch SWH that is turned on when the temperature of the discharge lamp α is low, and the on/off of this heater switch SWH is controlled. is controlled by the lamp heater 1 (a temperature sensor that is thermally coupled to the lamp heater 1).By the way, the discharge lamp Q,
When the engine is started, the filament (F, F2) is also preheated. In addition, in this discharge lamp lighting device, transformer 1 is 2
output windings L , , L 2 , one output winding L
1 to one end of the filament F, , F, and the other output winding #i 1.2 to the filament F,
, connect to the other end of F2, and connect the discharge lamp 0. The filament (F), F2 is preheated using high-frequency power even when the lights are turned on. The preheating current at the time of starting is made to flow from the DC power supply E, and in order to form this preheating loop and limit the preheating current (filament current), one output winding [4, A resistor Rf and a preheating switch SWf are connected between the negative electrode of the DC power source E and the negative electrode of the DC power source E. This preheating switch SWf is turned on when the lighting switch SW, ■ is off, and is switched in conjunction with the lighting switch SW+v. Note that the capacitor C1 connected between the output winding of the transformer T and one filament Fl of the discharge lamp η is a DC cut capacitor provided to form a preheating loop by the DC power source T). .

A conventional lamp heater 1 of this type is powered directly from a DC power source E or an AC power source e.

However, if the lamp heater 1 is powered from the DC power source E, the lamp heater 1 and the filaments Fl and F2 of the discharge lamp e
, it is necessary to supply power to each of inverter IV,
The burden on the DC power supply E increases.

Moreover, if the lamp heater 1 is powered from the AC power supply e,
There were drawbacks such as the need to take sufficient measures to insulate the lamp heater 1.

Furthermore, when looking at the discharge lamp lighting device itself, the filament current limiting resistor Rf conventionally built into the upstream side has a very high wattage, so the design must be designed to sufficiently dissipate the heat generated by this resistor Rf. The structure becomes larger. For this reason, there have been disadvantages such as the need to put a filler inside.

E Problem to be Solved by the Invention 1 The present invention has been made in view of the above points, and its purpose is to effectively utilize the heat generated by the resistance of the impedance for filament current limiting. An object of the present invention is to provide a discharge lamp and an α-lamp device that can be used in a compact manner and that can be miniaturized.

Means for Solving the Problems In order to achieve the above object, the present invention uses a lamp heater as at least a part of an impedance element that limits the filament current during filament preheating.

(Function) As described above, the present invention uses the lamp heater as at least a part of the impedance element that limits the filament current during filament preheating, thereby eliminating heat that was previously wasted and which was difficult to dissipate. , which can be effectively used as heat for heating the discharge lamp in the lamp heater, and also eliminates the need for heat dissipation design by eliminating large heat generating parts in the discharge lamp lighting device. It is.

(Example 1) An embodiment of the present invention is shown in FIGS. 1 to 3.

The fpJi diagram schematically shows the basic ellipse of the present invention, in which the lamp heater 1, whose operation was conventionally controlled by a heater switch, is connected to the positive electrode of the DC power source E and one filament.
F + and incorporated into the preheating loop, and used as at least part of the impedance element for filament current limiting, so that the lamp heater 1 warms the discharge lamp η at the same time as the filaments Fl and F2 are preheated. It is something. It should be noted that this discharge lamp lighting device warms the discharge lamp Q with the lamp heater 1 only at the time of startup when preheating is performed using the DC power source E. By the way, in this m1 diagram circuit, the filament current limiting resistor R'' is left as is, but the filament current limiting resistor Rf m!
Since & is mostly performed by the lamp heater 1, this resistor Rf is provided as an auxiliary one, and heat generation is not a problem. Further, as a preheating switch, a transistor such as a transistor shown in FIG. 1, a relay contact, or the like is used.

A specific example of this embodiment will be described below. As shown in FIG. 2, this discharge lamp lighting device is a DC type fi
An α lamp match SW is connected to both ends of E via a relay Ry, and power is supplied to an inverter I via a normally open contact r of this relay Ry, and an output 8 of a transformer T
Connect the normally closed contact r2 of the relay Ry between the wire and the negative pole of the DC power source E, and when this contact 2 is closed, apply a preheating current to the filament F2 through the lamp heater 1. Let it flow.

In this discharge lamp lighting device, when the DC type ME is turned on as shown in FIG. 3(a), the discharge lamp 0.0 is turned on by the DC power source E via the lamp heater 1 as shown in FIG. 3(b). A preheating current is applied to the filament (filament) F, , F, and at the same time, the lamp heater 1 generates heat due to the heater current flowing as shown in FIG. warm up. The broken line in FIG. 3(I) indicates the filament temperature, and the broken line in FIG. 3(e) indicates the lamp temperature. And Fig. 3 (d
), when the lighting switch SW is turned on, the normally open contact r1 closes, and high-frequency power is supplied from the inverter IV to the discharge lamp α, and the discharge lamp α instantly turns on as shown in (e) of the same figure. , α lights. At this time, since the normally closed contact r2 is opened, the preheating of the filament F+-F2 by the DC power source E is stopped. Therefore, no current flows to the lamp heater 1 (and the heating of the discharge lamp Q by the lamp heater 1 is also stopped). By the way, in a situation where the ambient temperature is sufficiently high and preheating by the lamp heater 1 is not required, Turn on the DC power supply E before lighting the discharge lamp 0.
The filaments Fl and F2 may be preheated for only a second, and then the lighting switch SW may be turned on to light the discharge lamp. In this way, by using the lamp heater 1 instead of a resistor for limiting the filament current,
There is an advantage that the heat that was wasted in the past and that it was difficult to dissipate can be effectively used as heat for warming the discharge lamp α. Unfortunately, there are no heat-generating parts inside the discharge lamp lighting device.
Therefore, there is no need to design the discharge lamp lighting device for heat dissipation, and the device can be made smaller. Furthermore, in the past, a switch was required for the lamp heater 1 and for preheating the filament (F), F2, but in this embodiment, one switch is required.
switch (contact rz). In addition,
In the case of this embodiment, since there are only modes for starting and lighting of the discharge lamp C, the capacity of the DC power source E may be set to whichever consumes more power. In this case,
When the power consumption during startup is large, the power consumption of the conventional filament current limiting resistor is eliminated, so the burden on the DC power source E is reduced.

(Example 2) Other embodiments of the present invention are shown in FIGS. 4 and 5.

In this embodiment, when the temperature of the discharge lamp η is low, the discharge lamp Q is warmed not only at the time of starting but also at the time of lighting the discharge lamp. In addition, in this embodiment, in order to guarantee the life of the discharge lamp η, the filament (F, F2) is always turned on for 2 to 3 seconds after turning on the lighting switch SW, regardless of the temperature of the discharge lamp 0°. Preheating and heating of the discharge lamp α by the lamp heater 1 are performed.

This will be explained in detail below. In this embodiment, the positive electrode side of the DC power supply E is connected to one end of the output winding L2 of the transformer T, and the lamp heater 1 is connected to the output winding #! One end of L and DC power supply E
When the transistor Q2 is turned on, it preheats the filament F, F2 and heats the discharge lamp. In this embodiment, preheating currents are applied to both filaments F, F2 in individual loops. Also, a resistor R connected between one filament F of the discharge lamp α and the output winding
1 is provided to limit the preheating current of the discharge lamp e due to high frequency power during the α lamp, and this filament)
A capacitor C2 connected to both ends of the series circuit of F + and the resistor R is provided to suppress heat generation of the resistor R1. The on/off state of the transistor Q2 is DC type r1. Bias resistance R2, R of transistor Q2 of E
, is controlled by a switch 5Wi1 that controls the supply to .

This switch SWs operates in conjunction with a temperature sensor S that detects the temperature of the discharge lamp α, and is turned on when the temperature of the discharge lamp is low and turned off when the temperature of the discharge lamp is high. When this switch 5w51 is turned on, the transistor Q2 is turned on,
A preheating current is passed through the transistor Q2 and the lamp heater 1 to both filaments F, , and T' by the DC power supply E, and the lamp heater 1 generates heat due to this preheating current, thereby warming the discharge lamp. When the switch SWs is off,
Since transistor Q2 is turned off, the preheating loop is opened and no preheating current flows.

By the way, as mentioned above, regardless of the temperature of the discharge lamp α,
For 2 to 34 seconds after turning on the lighting switch SW, the filaments F, F2 must be preheated and the discharge lamp 0. In order to perform the heating, the following structure is used. In other words, when the lighting switch SW is turned on, 2
In order to supply DC power E to the inverter IV with a delay of ~3 seconds, transistors Q4IQ9, capacitors C, and resistors R11R6 to R are used.

The time required for the voltage across the capacitor C3, which is charged via the resistor R1 when the DC power supply E is supplied, to reach the voltage that turns on the transistor Q, is set to 2 to 3 seconds, and after this time, the transistor Q is turned on.

Power is supplied to the inverter IV via the inverter IV. In addition, DC type t)! E and transistor Q.

A transistor Q is inserted between the transistor Q0 and a resistor R6 between the base of the transistor Q0 and the negative terminal of the DC power supply E.
When the switch SW is turned on, the transistor Q0 is turned on, and the DC power supply E is connected to the above circuit consisting of the transistors Q, Q5.
supply. Even when the temperature of the discharge lamp α is higher than a predetermined temperature and the switch SW s 1 is off, in order to preheat the filament (Fl-F2) and heat the discharge lamp via the lamp heater 1, The DC power supply E is connected to the bias resistor R2 of the transistor Q2 via the transistor Qo.
° R5 to turn on the transistor Q2 when the lighting switch SW is turned on, and also turn on the transistor Q1.
, is a circuit composed of the same switch 5WS2 and one resistor R1 as the above-mentioned switch SWs, and is designed to turn off the transistor Q2 after 2 to 3 seconds. That is, the transistor Q2 turned on by turning on the lighting switch SW is replaced with the transistor Q described above.

Similarly, by turning on the transistor Q when the voltage across the capacitor C1 reaches a predetermined voltage, 2 to 3
It turns off after a few seconds.

Now, assuming that the temperature of the discharge lamp is low at the time of starting, as shown by the broken line in Fig. 5(c), the temperature sensor
Wsl is turned on, transistor Q2 is turned on, and a preheating current is passed through the filament F, F2 through the lamp heater 1 as shown in FIG. 5(b), and the solid line in FIG. 5(e) As shown in , the lamp heater 1 warms the discharge lamp η by the heat generated by the preheating current. And the lighting switch S
If the temperature of discharge lamps 0 and 2 is still low when W is turned on, current continues to flow through lamp heater 1 even after discharge lamp t is turned on, as shown in FIG. A warm state is maintained. Note that when the lighting switch SW is turned on, the voltage across the capacitor C5 reaches a predetermined voltage after 2 to 3 seconds, but at this time the switch 5Ws2 is turned on, so the transistor Q is turned on.

is not turned on, and power supply to the lamp heater 1 is not cut off when the lighting switch SW is turned on. Then, when the temperature of the discharge lamp α reaches a predetermined temperature, the temperature sensor S turns off the switch SWs, and the current to the lamp heater 1 is cut off. In addition, in this case, switch S
By the time W S + * S W S 2 is turned off, the voltage across the capacitor C5 is already higher than the predetermined voltage, so at the same time, the transistor Q is turned on and the transistor Q2 is turned off, so that the lamp heater 1
The current is cut off at the same time as the switch WS2 is turned off.

Next, a case will be described in which the temperature of the discharge lamp C is already higher than the predetermined temperature at the time the lighting switch SW is turned on. At this time, the switches SWs, , 5Ws2 are off, so no current flows through the lamp heater 1. In this state, when the lighting switch SW is turned on, the transistor Q2
is turned on, and as a result, current flows through the lamp heater 1, preheating the lamp F1-F2 and heating the discharge lamp. From this point on, capacitor C7 is charged via resistor R4. And number 5! ! After the time t1 (2 to 3 seconds) shown in I(e), the transistors Q, , Q5 are turned on, and high frequency power is supplied from the inverter IV to the discharge lamp e, and the discharge lamp e is turned on. At this time, transistor Q3 turns on at the same time, so transistor Q2
The base current of is bypassed, transistor Q2 is turned off, and preheating of filaments F, F2 and heating of discharge lamp α are stopped. In this way, regardless of the temperature of the discharge lamp, just before the discharge lamp C is turned on, the filament F...
By preheating F2 and heating the discharge lamp, the life of the discharge lamp Q is guaranteed.

(Example 3) Still other embodiments of the present invention are shown in FIGS. 6 and 7.

In this embodiment, as shown in FIG. 6, the discharge lamp α is mounted on the same printed circuit board 2 as the discharge lamp lighting device including the inverter IV and the like. If the discharge lamp α is mounted on the same printed circuit board 2 in this manner, there is an advantage that wiring can be easily performed without routing the wiring to the discharge lamp η and the lamp heater 1. Also, as shown in Figure 7,
Connect one end of the lamp heater 1 to the negative pole of the DC power supply E (
With one end of the lamp heater 1 at ground potential), the lamp heater 1 can be used as a nearby conductor, in which case the discharge lamp 0. Improves starting performance. Note that the circuit in Figure 7 is different in that the preheating loop of F2 is the same as the preheating loop in Figure 4. , the operation is exactly the same as in the case of FIG.

1 Effects of the Invention 1 As described above, the present invention uses the lamp heater as at least a part of the impedance element that limits the filament current during filament preheating, so it eliminates the heat that was previously wasted and which is difficult to dissipate. The generated heat can be effectively used as heat for heating the discharge lamp in the lamp heater, and since there are no parts that generate a lot of heat in the discharge lamp lighting device, there is no need for heat dissipation design, and the device can be made more compact. There is. Furthermore, by using the lamp heater as at least part of the impedance element that limits the filament current, it is possible to eliminate the power consumption of the resistor for limiting the filament current, and it is also possible to reduce the burden on the DC power supply. effective.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a schematic configuration of one embodiment of the present invention, Fig. 2 is a specific circuit diagram of the same as the above, Fig. PJ3 is an explanatory diagram of the same as the above, Fig. 4 is a circuit diagram of another embodiment, 5 is an explanatory diagram of the same operation as above, FIG. 6 is a perspective view of the main part of another embodiment, and FIG.
This figure is the same circuit diagram as above, FIG. 8 is an explanatory diagram showing the rise characteristics of illuminance depending on the ambient temperature, and FIG. 9 is a circuit diagram of a conventional example. 1 is a lamp heater, α is a discharge lamp, and F, , F2 are filaments. Agent Patent Attorney Ishi Ill Ai Figure 2, Figure 3, Figure 5, Figure 4, Figure 6

Claims (1)

[Claims] (1) In a discharge lamp lighting device used in an optical image reading device that heats the discharge lamp using a lamp heater to speed up the time for the lamp light intensity to reach the minimum required illuminance of the image sensor, the lamp heater is used to preheat the filament. A discharge lamp lighting device characterized in that the discharge lamp is used as at least a part of an impedance element for limiting the filament current of the discharge lamp.