JP2522525Y2 - Purity measurement device - Google Patents

Description

[Detailed description of the invention] [Industrial applications]

The present invention relates to a purity measuring apparatus for measuring a landing characteristic of an electron beam on a phosphor in a cathode ray tube.

[Prior art]

For example, when the landing characteristics of an electron beam with respect to a phosphor in a color cathode ray tube are poor, color bleeding or the like occurs to degrade the quality of a displayed image. Therefore, as a method of measuring the purity value indicating the landing characteristic,
Conventionally, a method of (a) visually measuring the light emission luminance of a phosphor using a magnifying glass or the like, and (b) a method of observing the light emission luminance of a phosphor using a television camera have been used.

[Problems to be solved by the invention]

However, in the method of measuring the purity value, which is an index of the quality of the landing characteristics, based on the emission luminance of the phosphor visually measured with a magnifying glass or the like, a measurement error due to individual differences occurs, and a highly accurate purity value cannot be obtained. In addition, there is a problem that a visual impairment is given to the measurer. Further, in the method using a television camera, complicated operations such as focusing must be performed, so that it takes time, and there is a problem that a certain training is required for the measurement operation. The present invention has been made in view of the above problems,
It is an object of the present invention to provide a purity measuring device capable of obtaining a high-precision purity value with a simple operation in a short time.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention is to adjust the incident position of an electron beam incident on a fluorescent screen from an electron gun of a cathode ray tube at an arbitrary position on the tube surface in the horizontal scanning direction and the vertical scanning direction from the tube surface side. Deflecting means for deflecting the electron beam by a predetermined scanning amount in at least one direction, detecting means for detecting the light emission luminance of the phosphor screen when the electron beam is deflected at the arbitrary position in each deflection direction, and based on the detected light emission luminance signal. Means for calculating a purity value indicating a landing characteristic of the phosphor screen of the electron beam with respect to the phosphor, wherein the deflection means is constituted by a deflection coil having a U-shaped ferrite as a magnetic core. Here, when the purity value of the color cathode ray tube is to be measured, an optical filter for selectively detecting only the emission luminance of a desired color is added to the detection means.

[Action]

The electron beam is deflected at an arbitrary tube position from the tube surface by a predetermined scanning amount in, for example, a horizontal scanning direction and a vertical scanning direction. For example, the light is deflected in the horizontal and vertical directions by about 1/2 of the outer diameter direction of one phosphor. If the deflection direction of the deflection coil of the cathode ray tube and the direction of the electron gun were accurately adjusted so that the center of the electron beam coincided with the center of the phosphor, the electron beam could be scanned in the horizontal scanning direction. Even if the light is forcibly deflected to the left and right by about half the outer diameter of the body, the light emission luminance at each deflection position is the same because the area of the light emitting portion is the same. However, if the center of the electron beam is shifted from the center of the phosphor by, for example, half of the outer diameter of the phosphor in the left direction of the tube surface, the electron beam is shifted by half the outer diameter of the phosphor in the left and right directions. When the light is deflected forcibly, the light emitting area in the left direction becomes almost zero, and the light emitting area in the right direction approaches 100%. Therefore, a difference occurs in the light emission luminance in the left-right direction. Purity value calculating means calculates a purity value indicating a landing characteristic based on the difference in light emission luminance. This calculation is performed in the same way in the vertical direction,
Calculate the purity value in both vertical directions.

【Example】

Hereinafter, an embodiment of the present invention will be described. FIG. 1 is an external view showing an embodiment of the present invention, which comprises a measuring device main body 1 and a sensor unit 2. The measuring device main body 1 measures the landing characteristics of an electron beam with respect to the phosphor at the tube surface position based on a signal indicating the emission luminance of the phosphor detected by the sensor unit 2 at an arbitrary tube surface position of the cathode ray tube. Yes, the measured landing characteristics are displayed on the console panel 10
11 Horizontal and vertical purity values H (n)%, V
(M)% (n and m are natural numbers) are displayed numerically, and the position of the center of the electron beam with respect to the phosphor is displayed by a cross-shaped cursor mark 12 in the XY coordinate system. You. The sensor unit 2 deflects the incident position of the electron beam incident on the fluorescent screen from the electron gun of the cathode ray tube at an arbitrary position on the tube surface in the horizontal scanning direction and the vertical scanning direction from the tube surface side. The light emission luminance of the surface is detected for each deflection direction and input to the measuring device main body 1. Since the magnitude of the magnetic field required to deflect the electron beam by the sensor unit 2 varies depending on the thickness of the phosphor and the material of the shadow mask, a switch 13 for setting the magnitude of the magnetic field suitable for the cathode ray tube to be measured. Are provided on the console panel 10. In addition, since a certain time is required for the phosphor to emit light stably after the electron beam is incident, a switch for selecting and setting an appropriate stabilization time for each cathode ray tube to be measured.
14 are provided. FIG. 2 is a block diagram showing a circuit configuration of a main part of the apparatus main body 1 and the sensor section 2. In the apparatus main body 1, a purity value calculating circuit 15 and a deflection generating circuit 16 are provided. The sensor unit 2 includes deflection coils 20 and 21 for deflecting the electron beam, a photodiode 22 for receiving light generated from the phosphor screen, and an amplification of a light emission luminance detection signal output from the photodiode 22. Then, amplifiers 23 and 24 for inputting to the purity value calculating circuit 15 are provided. FIG. 3 is a perspective view showing a configuration of a part constituting a deflecting means for deflecting the electron beam in the sensor unit 2. The deflection coils 20, 21 are wound around U-shaped ferrite cores 25, 26. ing. The ferrite cores 25, 26 are arranged in the inner peripheral space of the core 26 so that they are orthogonal to each other. The photodiode 22 is disposed at the center position of the inner peripheral space of the core 25 so that the light receiving surface faces the opening of the cores 25 and 26. Photodiode 22
The light receiving surface receives light 3 emitted from the fluorescent screen of the measurement site. An optical filter 29 is provided in front of the incident direction, and is desired when the cathode ray tube to be measured is a color cathode ray tube. Photodiode that only emits light from phosphor screen of color
It is configured to be incident on the 22 light receiving surfaces. FIG. 4 is a plan view showing the relationship between the light receiving surface 22a of the photodiode 22 and the optical filter 26 as viewed from the light 3 incident direction. These components are inserted into a cylindrical body 27 having a diameter of about 18 mm. Next, the operation according to the above configuration will be described. First, the sensor unit 2 is applied to a desired tube surface position of the cathode ray tube to be measured. For example, as shown in marks 5a to 5e in FIG. 6, if it is specified that the purity value is measured at the upper left corner, upper right corner, lower left corner, lower right corner, and center of the cathode ray tube 4, first, the mark The tip of the sensor unit 2 is applied to the tube surface position 5a. In this state, the start switch 17 of the console panel 10 is turned on. Then, as shown in the time chart of FIG. 5, the deflection wave generation circuit 16 of the measuring apparatus main body 1 generates a positive polarity horizontal deflection signal at time t1 and a negative polarity horizontal signal at time t2. At time t3, a positive-polarity vertical deflection signal is generated, and at time t4, a negative-polarity vertical deflection signal is generated. The horizontal deflection signal is applied to the deflection coil 21, and the vertical deflection signal is applied to one deflection coil 20. When a horizontal deflection signal is applied to the deflection coil 21, the magnetic field 6 in the depth direction and the magnetic field in the front direction as shown in the explanatory diagram of FIG. 7 according to the polarity of the deflection signal. 7 is generated from the open end of the ferrite core 26. That is, when the horizontal deflection signal has a positive polarity,
A magnetic field 6 is generated, and in the case of negative polarity, a magnetic field 7 in the opposite direction is generated. In FIG. 7, if it is assumed that the upper direction of the figure is the horizontal scanning direction to the left toward the tube surface and the lower direction is the horizontal scanning direction to the right, a horizontal deflection signal of a positive polarity is generated. In the meantime, the electron beam 8 is deflected to the left, and conversely, when a negative horizontal deflection signal is generated, the electron beam 8 is deflected to the right. This deflection amount is present in the amplitude of the horizontal deflection signal flowing through the deflection coil 21.
Therefore, for example, the amplitude of the horizontal direction deflection signal is set so that the electron beam 8 is deflected by about 1/2 of the outer diameter of one phosphor, and the electron beam 8 is shifted leftward and rightward in the horizontal scanning direction. Deflect. As shown in FIG. 8 (a), the deflection direction of the deflection coil of the cathode ray tube 4 and the direction of the electron gun were accurately adjusted so that the center of the electron beam 8 coincided with the center of the phosphor 9. Then, even if the electron beam 8 is forcibly deflected to the left and right by about 1/2 of the outer diameter of the phosphor 9 in the horizontal scanning direction, as shown in FIGS. 8 (b) and 8 (c). In addition, the light emission luminance of the phosphor 9 at each deflection position is the same because the area of the portion that does not emit light is the same. However, as shown in FIG. 8 (d), when the center of the electron beam 8 is shifted from the center of the phosphor 9 to the right of the tube surface by 1/4 of the outer diameter of the phosphor, the electron beam 8 is When the phosphor is deflected to the left and right by about の of the outer diameter of the phosphor, the light emission area when deflected to the right becomes about の of the non-deflection as shown in FIG. The light emission area when the light is deflected in the direction is the same as when the light is not deflected as shown in FIG. That is, when the center of the electron beam 8 is shifted from the center of the phosphor 9 and the electron beam 8 is deflected by a predetermined amount to the left and right, a difference occurs in the emission luminance of the phosphor 9. Photodiode attached to two tips of sensor part
Reference numeral 22 receives the light generated from the phosphor 9 and outputs a signal corresponding to the received light luminance. This signal is amplified by the amplifiers 23 and 24 and then input to the purity value calculating circuit 15. The purity value calculating circuit 15 calculates PH = {LR / (LR + LL)} × 200−100, where LR is the light emission luminance of the phosphor 9 when deflected to the right and LL is the light emission luminance when deflected to the left. The purity value PH in the horizontal scanning direction is calculated by (1). When the measurement of the purity value PH in the horizontal scanning direction is completed, a vertical deflection signal of positive polarity is generated from the deflection wave generating circuit 16 at time t3 in FIG. 5B, and a vertical deflection signal of negative polarity is generated at time t4. Is generated. The electron beam 8 is deflected by a predetermined amount upward and downward by the vertical deflection signal. With this deflection, the photodiode 22 detects the emission luminance of the phosphor 9 when the photodiode 22 is deflected upward and downward. Therefore, the purity value calculating circuit 15 calculates the purity value PH in the vertical scanning direction according to PV = {LU / (LU + LLW)} × 200-100 LU: luminance when deflected upward LLW: luminance when deflected downward Calculate. As a result, the horizontal and vertical purity values PH, PV
, The purity value calculation circuit 15
The position shift of the electron beam with respect to the phosphor is displayed on a display 11 of a cross by a cross-shaped cursor mark 12. Actually, as shown in FIG. 6, in order to select a plurality of measurement points, an average value or a maximum value at each of these measurement points is displayed. As described above, in this embodiment, the cathode ray tube is 18
The electron beam is moved horizontally by a predetermined amount within a small range of about
The light is deflected in the vertical direction, and the purity value as an index of the landing characteristic is calculated based on the emission luminance of the phosphor at that time. Therefore, a high-precision purity value can be obtained in a short time by a simple operation. Further, since the deflection range is within a minute range of 18 mmφ, the intensity of the magnetic field required for deflection is kept to a minimum, and the problem of magnetizing the shadow mask can be prevented. In particular, since a ferrite core is used as the magnetic core of the deflection coil, the magnetic field intensity required for deflection can be obtained with a small-sized deflection coil, and the size of the sensor unit can be reduced. By the way, when the exterior of the photodiode 22 is made of a magnetic material, it is assumed that the distribution of the deflection magnetic field changes and the desired magnetic field distribution is not obtained. Therefore, as shown in another embodiment of the sensor unit 2 shown in FIG. 9, one input surface of the optical fiber 28 is arranged at the position of the light receiving window of the photodiode 22, and the output surface of the other end is connected to the ferrite core 26. Is connected to the light receiving surface of the photodiode 22 provided behind. Alternatively, the exterior of the photodiode 22 is made of a non-magnetic material such as ceramic. With this configuration, the deflection magnetic field distribution is not disturbed, and the purity value can be measured with higher accuracy. The deflection direction is two directions, horizontal and vertical, but can be configured in only one direction according to the specifications of the cathode ray tube.

[Effects of the Invention] As described above, the present invention is realized from the cathode ray tube surface side.
The electron beam is deflected by a predetermined amount in at least one of the horizontal and vertical directions within a minute range of about 18 mmφ, and the purity value as an index of the landing characteristic is calculated based on the emission luminance of the phosphor at that time. Therefore, a high-precision purity value can be obtained in a short time by a simple operation. In addition, the U-shaped ferrites are arranged in an orthogonal relationship to each other, and the light receiving element is arranged in the U-shaped ferrite so that the light receiving surface faces the opening of the U-shaped ferrite in the inner peripheral space, so that the deflection range is reduced. It can be kept in a minute range of about 18 mmφ, the intensity of the magnetic field required for deflection is kept to a minimum, and the problem of magnetizing the shadow mask can be prevented. In particular, since a ferrite core is used as the magnetic core of the deflection coil, the magnetic field intensity required for deflection can be obtained with a small-sized deflection coil, and the size of the sensor unit can be reduced.

[Brief description of the drawings]

FIG. 1 is an external view showing an embodiment of the present invention, FIG. 2 is a block diagram showing a circuit configuration of a main part of the apparatus, FIG. 3 is a perspective view showing a configuration of an electron beam deflecting means in a sensor unit,
FIG. 4 is a plan view showing the relationship between a light receiving element and an optical filter, FIG. 5 is a waveform diagram of a deflection signal for deflecting an electron beam, and FIG. 6 shows an example of a tube surface portion for measuring a purity value. FIGS. 7 and 8 are explanatory views for explaining the electron beam deflection operation, and FIG. 9 is a perspective view showing another embodiment of the optical system for measuring the emission luminance of the phosphor. DESCRIPTION OF SYMBOLS 1 ... Measurement device main body, 2 ... Sensor part, 3 ... Light, 4 ... Cathode ray tube, 8 ... Electron beam, 9 ... Phosphor, 10 ... Console panel, 11 ... Display, 12 ... Cursor mark, 13, 14 ... Switch , 15… Purity value calculation circuit, 16… Polarized wave generation circuit,
17 ... Start switch, 20,21 ... Deflection coil, 22 ... Photodiode, 23,24 ... Amplifier, 25,26 ... Ferrite core, 27 ... Cylinder, 28 ... Optical fiber, 29 ... Optical filter.

Claims (2)

(57) [Scope of request for utility model registration] 1. A deflection means for changing an incident position of an electron beam incident on a fluorescent screen from an electron gun of a cathode ray tube by a predetermined scanning amount in an arbitrary position on the tube surface in horizontal and vertical directions from the tube surface side. Detecting means for detecting the light emission luminance of the phosphor screen at each of the deflection directions when the electron beam is deflected; and a purity indicating a landing characteristic of the phosphor screen of the electron beam with respect to the phosphor based on a signal of the detected light emission luminance. A purity value calculating means for calculating a value, wherein the deflecting means has a U-shaped ferrite as a magnetic core, and is constituted by a pair of deflecting coils arranged in an orthogonal relationship to each other; The light receiving element is configured to output a signal of a level corresponding to the light emission luminance. The light receiving element is disposed in the inner peripheral space of the U-shaped ferrite, and the light receiving surface thereof is the U-shaped ferrite.
A purity measuring device, which is disposed so as to face the opening of the letter-shaped ferrite. 2. A deflecting means for deflecting an incident position of an electron beam incident on a fluorescent screen from an electron gun of a cathode ray tube by a predetermined scanning amount in a horizontal and vertical direction from the tube surface at an arbitrary position on the tube surface. Detecting means for detecting the light emission luminance of the phosphor screen at each of the deflection directions when the electron beam is deflected; and a purity indicating a landing characteristic of the phosphor screen of the electron beam with respect to the phosphor based on a signal of the detected light emission luminance. A purity value calculating means for calculating a value, wherein the deflecting means has a U-shaped ferrite as a magnetic core, and is constituted by a pair of deflecting coils arranged in an orthogonal relationship to each other; A light-receiving element that outputs a signal at a level corresponding to the light emission luminance, and light emitted from the phosphor screen passes through the inner peripheral side space of the U-shaped ferrite to a light-receiving surface of the light-receiving element. Ku purity measuring apparatus characterized by being composed of an optical system.