JPH02230697A - Power source device for vacuum tube type light emitting tube - Google Patents

Abstract

PURPOSE:To stabilize and control a plate voltage without using a resistance for high voltage by controlling the plate voltage of a vacuum tube type light emitting tube by detecting the current flowing through an auxiliary plate. CONSTITUTION:A DC-DC converter 2 for supplying a plate power is connected to a plate P of a tetrode vacuum tube type light emitting tube 1. An output terminal of a current detection circuit 4 for detecting the current flowing through the backplate BP of the light emitting tube 1 is connected to the voltage regulator terminal of the converter 2. The converter is adjusted in advance to output a specified voltage and its voltage adjusting terminal is controlled by the output signal of the current detection circuit 4 to control the output voltage of the DC-DC converter 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device that supplies power to a vacuum tube type arc tube that can be applied, for example, to a backlight source of a display.

[Conventional technology] Conventional. The output voltage of the power supply that supplies power to the vacuum tube type arc tube is. The method was to detect the output voltage and control the power supply voltage. but. Generally, the output voltage of the power supply supplied to the plate of this type of vacuum tube arc tube is a high voltage of several KV, and in order to detect this high voltage, a resistor with a high resistance value is required. The resistance is. temperature. Humidity. There were problems such as insufficient stability and reliability over time and relatively high cost.

[Problem to be solved by the invention] As described above. Since high voltage is co-supplied to the plate of a vacuum tube arc tube, the high voltage detection resistor is large in shape due to its nature. Stability and reliability are not fully satisfactory.
And it was relatively expensive.

Therefore, the present invention has been made in view of the above circumstances.
It is possible to stabilize and control the plate voltage of high voltage circuits without using expensive high voltage resistors. Another object of the present invention is to provide a power supply device for a vacuum tube type arc tube that can control luminance with good luminous efficiency.

[Means and effects for solving the problem] The present invention is intended to achieve the above object. In a power supply device used for a vacuum tube type arc tube that has an auxiliary plate, cathode, or heater that flows a current proportional to the brightness.
The plate voltage of the vacuum tube type arc tube is controlled by detecting the current flowing through the auxiliary plate, the cathode, or the heater. (7) It is characterized by making use of the fact that the current flowing through the heater is proportional, and stabilizing the plate voltage by detecting the current and applying feedback.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the invention. That is. The tetrode vacuum tube type arc tube 1 consists of a plate P, a grid G, a heater H, and an auxiliary plate for scattering the electron beam, such as a back plate BP. The back plate BP passes a current proportional to the brightness of the arc tube 1. This tetrode vacuum tube arc tube] is shown in Figure 2. The plate P is configured as a planar body consisting of an electrode and a light emitting surface. A DC voltage is applied to this plate P from the DC-DC converter 2. A heater power source 3 is connected to the heater H. When the electron beam emitted from the heater H hits the plate P. The luminous material of the plate P emits light. The amount of light emitted is approximately 20,000 candela or more.

Emission brightness is controlled by controlling the voltage applied to grid G. Also. This is possible by controlling the electron beam from the heater H.

That is. A DC-DC converter 2 for supplying plate power is connected to the plate P of the tetrode vacuum tube type arc tube 1. The output terminal of a current detection circuit 4 for detecting the current flowing through the back plate BP of the arc tube 1 is connected to the voltage adjustment terminal of the DC-DC converter 2. The DC-DC converter 2 is adjusted in advance to output a predetermined voltage. Furthermore, the voltage adjustment terminal of this DC-DC converter 2 is controlled by the output signal of the current detection circuit 4, and the DC-DC
The output voltage of the converter 2 is controlled as shown in a and b in FIG. That is, as shown in Fig. 3, for example, when the brightness is increased, the plate current increases. The output high voltage (plate voltage Vp) of the DC-DC converter 2 is DC-DC
However, it decreases due to stability due to changes in the load of converter 2. When a predetermined voltage is applied to the back plate BP of the arc tube 1. As shown in FIG. 6, since a back plate current proportional to the brightness flows, 2, by detecting this current with the current detection circuit 4, the current is generated as shown in a and b of FIG. It is possible to control the high plate voltage Vp applied to the plate P.

In other words. The plate voltage Vp can be freely controlled by the current detected by the current detection circuit 4. Unlike conventional methods, there is no need for a high voltage detection resistor.

or. With this power supply. As shown in Figure 4. Output voltage cvp of DC-DC converter 2 during non-lighting and low brightness
) is lowered. At high brightness, it is possible to increase the voltage (Vp >
In other words, it can be used with good luminous efficiency (
(See Figure 5).

In the above embodiment, the case where the plate voltage is controlled by detecting the current flowing through the auxiliary plate 1 note is explained.
Not limited to this. In a power supply device used for a vacuum tube type arc tube that has a cathode or heater that flows a current proportional to the brightness. The same method can be used to control the plate voltage of the vacuum tube type arc tube by detecting the current flowing through the cathode or the heater.

or. In the above embodiment, DC is used to generate the plate voltage etc.
-I explained the case where a DC converter is used.6
Not limited to this method. Regardless of type. Any power source that has an oscillation circuit inside the power source can be applied.

[Effects of the Invention] As described above, according to the present invention. In a power supply device used for a vacuum tube type luminous tube with an auxiliary plate. The plate voltage of the high voltage circuit can be stabilized and controlled without using expensive high voltage resistors. The brightness of the arc tube can be controlled with good luminous efficiency. still. Because it does not use high resistance for high voltage. temperature. Humidity. Reliability can be improved against environments such as vibration.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention. FIG. 2 is a perspective view showing an example of a tetrode vacuum tube type arc tube according to the present invention.
FIGS. 3 to 6 are characteristic diagrams showing each characteristic of the power supply device of the present invention. 1... Tetrode vacuum tube type luminous tube. 2...DC-DC converter. 3... Heater power supply, 4... Current detection circuit. Applicant's representative Patent attorney Takehiko Suzue (mA)

Claims (2)

[Claims] (1) A power supply device for use in a vacuum tube type arc tube having an auxiliary plate through which a current proportional to brightness flows, characterized in that the plate voltage of the vacuum tube type arc tube is controlled by detecting the current flowing through the auxiliary plate. Vacuum tube type luminous tube power supply. (2) In a power supply device used for a vacuum tube arc tube having a cathode or heater that flows a current proportional to brightness, the plate voltage of the vacuum tube arc tube may be controlled by detecting the current flowing through the cathode or heater. Features a vacuum tube type luminous tube power supply device.