JPH09320470A - Stray emission measuring apparatus for color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure stray emission and leakage current of a color cathode ray tube within a short time without requiring complicated switching of high voltage circuit by installing a grid power source, a measuring means to measure the quantity of luminescence, and a processing apparatus. SOLUTION: A photoelectric conversion element 15 to detect the luminescent state of the electroluminescent face of a color cathode-ray tube 1 is installed in front of the tube 1 and the output of the element 15 is processed by a processing apparatus 16. The processing apparatus 6 controls a first grid power source 12, a second grid power source 13, and a third grid power source 14 and further processes the current measured by ammeters 9, 10, 11. In other words, the apparatus 16 computes the inclination of the quantity of luminescence obtained at the time when the second grid voltage is elevated from zero to a prescribed value and then the third grid voltage is elevated from zero to a prescribed value based on the output properties of the ammeters 10, 11 and computes the stray emission quantity of each electrode. Consequently, since stray emission and the leakage current can be simultaneously computed without switching, so that the measuring time can be remarkably shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stray emission measuring device for a color cathode ray tube.

[0002]

2. Description of the Related Art Conventionally, unnecessary electron emission called stray emission from an internal electrode of a color cathode ray tube is measured by applying a predetermined voltage to the color cathode ray tube. In order to prevent the original electron emission from the cathode, a cut-off bias is applied to the cathode, and the current flowing in and out of the electrode when the voltage of the electrode to be measured is raised or lowered is measured. The presence / absence or the amount of stray emission from the light partially emitted on the light emitting surface formed of the phosphor that should be used is determined.

[0003]

Usually, the main source of stray emission in color cathode ray tubes is the electrode of the electron gun. However, since the electron gun of the color cathode ray tube has many electrodes, it is necessary to switch the electrode peripheral circuit.
In particular, since a high voltage is applied to the acceleration electrode and the focus electrode, there is a problem that the measurement time becomes long because the measurement accuracy is secured and the operation of the switching circuit is included.

An object of the present invention is to provide a stray emission measuring device capable of measuring stray emission and leak current of a color cathode ray tube in a short time without requiring complicated switching of a high voltage circuit. .

[0005]

A first means of the present invention for solving the above-mentioned problems is to provide a grit power source for applying an arbitrary voltage to the second grit and the third grit of the color cathode ray tube, and the grit power source of the color cathode ray tube. The measuring means, which is arranged in front of the light emitting surface and measures the amount of light emission, and the grit power source of the second grit and the grit power source of the third grit are controlled to raise the second grit voltage from zero to a constant value, and then And a processing unit for calculating the slope from the output characteristic of the measuring unit of the light emission amount obtained when the 3-grid voltage is increased from zero to a constant value, and obtaining the stray emission amount from each electrode. .

The second means of the present invention for solving the above-mentioned problems is the first means, wherein after the second grit voltage reaches the first constant value, the second grit voltage is further changed to the second grit voltage. It is characterized by increasing to a constant value of 2.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the color cathode ray tube 1 includes an anode 2, a cathode 3, a first grit 4, a second grit 5 and a third grit 6 as is well known.
A predetermined voltage is applied to the anode 2 from an anode power source 7. In order to prevent electron emission from the cathode 3,
A bias voltage for cutoff is applied by the cathode power supply 8. The first grit 4, the second grit 5 and the third grit 6 are connected to the first grit 4 via the ammeters 9, 10 and 11, respectively.
The grid power supply 12, the second grid power supply 13, and the third grid power supply 14 are connected.

In front of the color cathode ray tube 1, a photoelectric conversion element 1 for detecting the light emitting state of the light emitting surface of the color cathode ray tube 1.
5, the output of the photoelectric conversion element 15 is processed by the processing device 16. Further, the processing device 16 controls the voltages of the first grid power supply 12, the second grid power supply 13 and the third grid power supply 14, and further processes the current measured by the ammeters 9, 10, 11.

Next, the measurement will be described with reference to FIG. FIG.
As shown in (a), the second grid voltage EC ₂ of the second grid power supply 13 and the third grid voltage EC ₃ of the third grid power supply 14 are changed with time. First, at time t ₀ , the second grit voltage EC ₂ and the third grit voltage EC ₃
Both are set to zero. However, other electrode voltages are added. Next, the second grid voltage EC ₂ is increased with time from the time t ₀ to the time t ₁ , and the time t
_{When set to 1} , the first constant value V1 is set. The third grid voltage EC ₃ is increased at time t ₂ and is set to a constant value V3 at time t ₃ . Then raised the second grid voltage EC ₂ at time t _4, the second predetermined value V2 at time t _5. This second
After reaching a constant value V2 of 0, it is set to zero at time t ₆ .

The light emitting state of the light emitting surface of the color cathode ray tube 1 in the series of voltage changes is detected by the photoelectric conversion element 15 and sent to the processing device 16. The output of the photoelectric conversion element 15 is the amount due to the stray emission of the color cathode ray tube 1.
The output of the photoelectric conversion element 15 has a stepwise waveform as shown in FIG. Each slope of this step-like waveform means stray emission using each electrode as a radiation source. The slopes A ₁ , A ₂ , A ₃ are the third grit 6,
The stray emissions of the second grit 5 and the first grit 4 are shown. In the processing device 16, the stray emission of the third grit 6 is obtained from the magnitude of the inclination a ₁ of the inclination A ₁ . Similarly, from the inclination a ₂ to the second grit 5,
The stray emission of the first grit 4 is obtained from the inclination a ₃ .

Further, at time t ₂ , the ammeter 11 connected to the third grit 6 can measure the leak current of the third grit 6. At time t ₅ , the leak current of the first grid 4 is obtained by the ammeter 9. Further, at time t ₆ , the leak current of the second grid 5 can be obtained by the ammeter 10.

[0012]

According to the present invention, a second color cathode ray tube is provided.
A grit power source for applying an arbitrary voltage to the grit and the third grit, a measuring unit arranged in front of the light emitting surface of the color cathode ray tube for measuring the amount of light emission, a grit power source for the second grit and a grit power source for the third grit. The slope is calculated from the output characteristic of the measuring means of the light emission amount obtained when the second grit voltage is increased from zero to a constant value and then the third grit voltage is increased from zero to a constant value by controlling. Since the apparatus is provided with a processing device for obtaining the amount of stray emission from the electrodes, stray emission and leak current can be obtained at the same time without switching, and the measurement time can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a stray emission measuring device for a color cathode ray tube of the present invention.

2A is a voltage application diagram, and FIG. 2B is a stray emission output characteristic diagram.

[Explanation of symbols]

1 Color Cathode Ray Tube 5 Second Grit 6 Third Grit 9, 10, 11 Ammeter 13 Second Grit Power Supply 14 Third Grit Power Supply 15 Photoelectric Conversion Element 16 Processing Device EC ₂ Second Grit Voltage EC ₃ Third Grit Voltage

Claims (2)

[Claims] 1. A second grit and a third grate of a color cathode ray tube.
A grit power source for applying an arbitrary voltage to the grit, a measuring means arranged in front of the light emitting surface of the color cathode ray tube for measuring the amount of light emission, a grit power source of the second grit and a grit power source of the third grit are controlled, The slope is calculated from the output characteristic of the measuring means of the light emission amount obtained when the 2 grit voltage is increased from zero to a constant value and then the third grit voltage is increased from zero to a constant value, and the stray from each electrode is calculated. A stray emission measuring device for a color cathode ray tube, comprising: a processing device for determining an emission amount. 2. The color cathode ray tube according to claim 1, wherein after the second grit voltage reaches a first constant value, the second grit voltage is further increased to a second constant value. Stray emission measuring device.