JPH0429176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for inspecting color picture tubes, and in particular, detects color picture tubes with factors that deteriorate their emission characteristics at an early stage, and sends them to a regeneration process.
The present invention relates to a color picture tube inspection method that allows the information to be used in the manufacturing process.

[Technical background of the invention and its problems]

The manufacture of color picture tubes is usually carried out in the following process order.

First, a fluorescent screen consisting of a phosphor layer that emits red, green, and blue colors is adhered to the inner surface, a panel is attached with a shadow mask, and a funnel and a net are formed with an inner conductive film adhered thereto. The funnel neck is sealed with frit glass or the like to form a so-called complete bulb.

Next, the electron gun assembled on the stem is inserted into the open end of the neck of this complete valve, and the neck and stem are welded together.

Next, the inside of the tube is evacuated through an exhaust pipe provided in the stem, and the exhaust pipe is sealed.

Next, perform a getter flush to create a high vacuum inside the tube.

Next, attach the explosion-proof band to the side wall of the panel.

Next, after undergoing a cathode aging process and high-pressure treatment (voltage resistance treatment), various product inspections are performed. This product inspection includes various inspection items, one of which is an emission inspection.

This emission test includes an emission rise characteristic that evaluates the rapid movement of the cathode, and a saturation emission characteristic that evaluates the cathode's emission ability.

Next, inspection of the rise characteristics of this emission will be explained with reference to FIGS. 1 and 2.

That is, a panel 3 having a fluorescent screen 1 adhered thereon and a shadow mask 2 disposed at a predetermined distance from the fluorescent screen 1, an internal conductive film 4, and an anode electrically connected to the internal conductive film 4. A funnel 6 on which a terminal 5 is formed, a heater 9 assembled on a stem 8 welded to a neck 7 welded to the funnel 6, and arranged in the neck 7, a cathode 10, a first grid 11, a second grid. In a color picture tube equipped with an electron gun composed of a grid 12, a third grid 13, and a fourth grid 14, the fourth grid 14 and the stem are electrically connected to the anode terminal 5 via the internal conductive film 4. The third grid 13 and the second grid 12 are electrically connected via the
Applying a voltage of 200 to 300 V, directly grounding the first grid 11, applying the rated voltage to the cathode 10, and applying the rated voltage to the heater 9 while grounding through the cathode ammeter 16, The rise characteristic of the cathode emission is examined by reading the time t when the cathode current flowing as shown in the curve 25 shown in FIG. 2 reaches a specified value.

In such an inspection of the emission rise characteristic, the electrons emitted from the cathode 10 are transferred to the first grid 1 as indicated by the arrow 17 shown in FIG.
1, 2nd grid 12, 3rd grid 13, 4th grid
It collides with the grid 14 and is captured.

In addition, the saturation emission characteristic test is carried out through the anode terminal 5 and the internal conductive film 4, as shown in FIG.
A rated high voltage is applied to the grid 14 from the power supply 18, a rated focus voltage is applied to the third grid 13 from the power supply 19, and a power supply 2 is applied to the second grid 12.
Applying a voltage of 0 to +200 to 300 V, directly grounding the first grid, applying a rated voltage to the cathode 10, and grounding via the cathode ammeter 10,
By mounting and operating the deflection yoke near its normal mounting position, the electron beam 21 is scanned over the fluorescent screen 1.

In such a test of saturation emission characteristics, the electron beam emitted from the cathode 10 collides with the fluorescent screen 1, the shadow mask 2, the mask claim (not shown), etc., and is captured as indicated by diagonal lines 22 ₁ and 22 ₂ .

Therefore, according to this emission test, the cathode 10 has a low emission capacity and the required cathode current value cannot be obtained from the color picture tube, the grids 11, 12, 13, 14, the shadow mask 2, the phosphor screen 1, etc. For color picture tubes that have residual gas sources that could not be sufficiently removed during the exhaust process or cathode aging process,
With the inspection method shown in Figures and Figure 3, gas is released during measurement and the emission decreases, so it can be detected as a defective emission, and such a color picture tube can be rejected as having the cause of a defective emission. .

However, the color picture tube has a residual gas source in the flute part ₆₁ of the funnel at the boundary between the funnel 6 and the net 7, and the cathode 10 due to the discharge inside the tube that occurs between the high voltage electrode and the low voltage electrode during actual operation.
There is a problem in that the conventional inspection methods shown in FIGS. 1 and 3 cannot sufficiently detect the residual gas source outside the area where the electron beam collides.

Further, when a color picture tube is installed in a television set and is in operation, a portion of the electron beam emitted from the cathode may collide with the flute portion ₆₁ of the funnel due to manufacturing variations in the tube or deflection yoke. When a part of the electron beam collides with the flute portion 6 ₁ of the funnel in this way, _the conventional inspection method
Color picture tubes with a residual gas source are shipped without being detected as having an emission defect, resulting in the problem that some of them are returned as emission defects after they reach the customer's set assembly line or on the market. There is also.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and is a color picture tube that can detect and reject color picture tubes in advance during the manufacturing process, which have the cause of emission deterioration but are not detected by conventional inspection methods. The purpose is to provide a method for inspecting picture tubes.

[Summary of the invention]

That is, the present invention applies to color picture tubes that have undergone the steps of evacuation, getter flushing, high pressure treatment, and cathode aging. At the same time, the high voltage applied to the anode terminal is made higher than the rated value, and the deflection yoke is moved back toward the electron gun from its normal mounting position to cause the electron beam to collide with the flute portion of the funnel of the color picture tube for a predetermined period of time. This color picture tube inspection method is characterized in that, after the treatment, an emission inspection is performed to inspect the rise characteristics of the cathode emission and the saturation emission characteristics of the cathode.

[Embodiments of the invention]

Next, an embodiment of the color picture tube inspection method of the present invention will be explained with reference to FIG. In the figure, the same reference numerals as in the conventional example indicate the same parts.

That is, a panel 3 having a fluorescent screen 1 deposited on its inner surface and a shadow mask 2 disposed at a predetermined distance from the fluorescent screen 1, an internal conductive film 4, and electrically connected to the internal conductive film 4. A heater 9, a cathode 10, a first grid 11, a first grid 11, a cathode 10, a heater 9, a cathode 10, a first grid 11, a first grid 11, a funnel 6 on which an anode terminal 5 is formed, and a stem 8 welded to a neck 7 welded to the funnel. The color picture tube is equipped with an electron gun consisting of a second grid 12, a third grid 13 and a fourth grid 14, and is equipped with exhaust, getter flash, high pressure processing,
After each step of cathode aging is completed, a voltage several percent higher than the rated voltage is applied from the power supply 28 to the fourth grid 14, which is electrically connected from the anode terminal 5 through the internal conductive film 4. Rated voltage from power supply 19, power supply 2 to second grid 12
Apply the rated voltages from 0 to 0, directly ground the first grid 11, lower the voltage of the heater 9 by a few percent from the rated voltage, raise the cathode voltage applied to the first grid 11 at ground potential from the rated value, and then connect the cathode ammeter 1.
The cathode current shown in 6 is increased by a few percent over the rated value, and the deflection yoke (not shown) is moved back from its normal position toward the electron gun (rearward) so that the electron beam 31 also collides with the flute portion ₆₁ of the funnel 6. Perform a running process for several 10 minutes.

The purpose of increasing the cathode current and the anode voltage as well as retracting the position of the deflection yoke from its normal position is to accelerate the electron beam from the cathode 10 to the flute portion ₆₁ of the funnel to generate a high-energy beam. Make more electron beams collide,
In order to effectively cause gas release from the residual gas source in the flute section ₆₁ of the funnel, and to measure the resulting drop in emission in an emission inspection and reject it as a cause of emission failure, and to identify the cause of discharge. This is to promote electrical discharge to the color picture tube.

By doing so, the electron beam emitted from the cathode 10 collides with the fluorescent screen 1, the shadow mask 2, the mask claim (not shown), etc., and is captured as shown by diagonal lines 22 ₁ and 22 ₂ . It also collides with the part 6 ₁ as shown by the diagonal line 22 ₃ , which can promote gas release from the residual gas source in the flute part 6 ₁ of this funnel, and the resulting drop in emissions can be measured by an emission test. This makes it possible to reject it as having the cause of an emission failure.

In the above embodiment, a color picture tube equipped with an electron gun having four grids was described, but it goes without saying that the present invention can also be applied to color picture tubes equipped with electron guns of other shapes.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to extremely reduce the emission defect rate in television set manufacturers and the market, and it is possible to discover factors causing emission defects at an early stage in the manufacturing process, and to use this information in the manufacturing process. By using it in the process, it is possible to prevent quality accidents,
Its industrial value is extremely large.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a conventional cathode rise characteristic testing method, Fig. 2 is a curve diagram showing the cathode current rise time, Fig. 3 is an explanatory diagram showing a conventional saturation emission characteristic testing method, and Fig. 4 FIG. 1 is an explanatory diagram showing an embodiment of the color picture tube inspection method of the present invention. DESCRIPTION OF SYMBOLS 1... Fluorescent screen, 2... Shadow mask, 3... Panel, 4... Internal conductive film, 5... Anode terminal, 6... Funnel, 6 ₁ ... Flute part of funnel, 7... Network, 8... ...Stem, 9
... Heater, 10 ... Cathode, 11 ... First grid, 12 ... Second grid, 13 ... Third grid, 14 ... Fourth grid, 15, 18, 1
9, 20, 28...Power supply.

Claims (1)

[Claims] 1. For the color picture tube that has undergone the exhaust, getter flush, high pressure treatment, and cathode aging steps, the heater voltage is lowered below the rated value, and the cathode voltage relative to the first grid at ground potential is increased above the rated value to increase the cathode current above the rated value. The high voltage applied to the anode terminal is made higher than the rated value, the deflection yoke is moved back toward the electron gun from the normal device position, and the flute part of the funnel of the color picture tube is made to collide with the electron beam and processed for a predetermined period of time. A method for inspecting a color picture tube, characterized in that an emission inspection is performed to inspect the rise characteristic of the cathode emission and the saturation emission characteristic of the cathode.