JP2006013686A - Cathode ray tube display, image display and its driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display ensuring good velocity modulation effect even in high frequency regions. <P>SOLUTION: An image display 100 comprises a cathode ray display 1 and a drive circuit 101 wherein the drive circuit 101 comprises a drive circuit 102, a velocity modulation circuit 103, a switching signal generating circuit 104, an emitter switching circuit 105 and a lead-out electrode power supply 106. The emitter switching circuit 105 switches emitter regions E1-E5 emitting electrons and not emitting electrons based on an emitter switching signal outputted from the switching signal generating circuit 104 and a predetermined voltage supplied from the lead-out electrode power supply 106. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cathode ray tube apparatus, an image display apparatus, and a method for driving the image display apparatus provided with speed modulation means that delays and accelerates the scanning speed of an electron beam emitted from an electron gun.

A conventional cathode ray tube device is provided with a magnetic field coil in the vicinity of the electron gun as a speed modulation means for delaying and accelerating the scanning speed of the electron beam emitted from the electron gun. A magnetic field is generated by flowing a desired current through the magnetic field coil to obtain a speed modulation effect that delays and accelerates the scanning speed of the electron beam.
JP-A-5-343000 "Sharp image TV-Improving image quality by electromagnetic speed modulation"; Katsuhiko Yamamoto et al. National Technical Report Vol. 25 No. 3 1979

  However, in the configuration of the conventional cathode ray tube device described above, the velocity modulation effect is obtained by the magnetic field of the magnetic field coil provided in the vicinity of the electron gun. Therefore, eddy current is generated in the metal member constituting the electron gun, and high frequency characteristics are obtained. There is a problem of deterioration.

  An object of the present invention is to provide a cathode ray tube device, an image display device, and a driving method of the image display device that can obtain a good speed modulation effect even in a high frequency region.

  A cathode ray tube apparatus according to the present invention includes an electron gun that is housed in a neck portion of a funnel and emits an electron beam, and a deflection yoke that is attached to the outer peripheral surface of the funnel and deflects the electron beam. The electron gun includes a field emission electron source element in which a plurality of emitter regions for emitting electrons are formed, and the plurality of emitter regions are formed along a scanning direction of the electron beam. In the plurality of emitter regions, an emitter region that emits electrons and an emitter region that does not emit electrons are switched.

  An image display device according to the present invention includes the cathode ray tube device according to the present invention and an emitter switching circuit for switching the emitter region.

  According to another aspect of the present invention, there is provided a method of driving an image display apparatus, comprising: an electron gun having a field emission electron source element formed with a plurality of emitter regions emitting electrons along a scanning direction of an electron beam; A cathode ray tube device having a deflection yoke for deflecting an electron beam, a speed modulation circuit for converting a luminance signal into a change amount per unit time, and the change amount obtained by the speed modulation circuit when the brightness signal rises Or a switching signal generation circuit for outputting an emitter switching signal to the emitter switching circuit when the amount of change at the time of falling, and an extraction electrode power supply for supplying a voltage to the emitter switching circuit, output from the switching signal generation circuit An emitter region that emits electrons out of the plurality of emitter regions based on the emitter switching signal that is generated and the voltage supplied from the extraction electrode power source. And performs switching of the emitter region which does not emit electrons.

  According to the present invention, it is possible to provide a cathode ray tube apparatus, an image display apparatus, and a driving method for the image display apparatus that can obtain a favorable speed modulation effect even in a high frequency region.

  In the cathode ray tube device according to the present embodiment, it is preferable to switch the emitter region in accordance with a change in luminance signal.

  Further, when the luminance signal rises, electrons are emitted only from an emitter region formed on the side opposite to the scanning direction of the electron beam among the plurality of emitter regions, and when the luminance signal falls In this case, it is preferable to switch the emitter region so that electrons are emitted only from the emitter region formed in the electron beam scanning direction and the forward direction side among the plurality of emitter regions.

  Furthermore, it is preferable that at least five of the plurality of emitter regions are formed.

  Further, it is preferable that electrons are always emitted from the central emitter region among the five emitter regions.

  The image display device according to the present embodiment includes any one of the above-described cathode ray tube devices and an emitter switching circuit for switching the emitter region.

  Further, a speed modulation circuit that converts the luminance signal into a change amount per unit time, and the change amount obtained by the speed modulation circuit is a change amount at the rising or falling time of the luminance signal. A switching signal generation circuit that outputs an emitter switching signal to an emitter switching circuit; and an extraction electrode power source that supplies a voltage to the emitter switching circuit, wherein the emitter switching circuit outputs the emitter switching output from the switching signal generation circuit The emitter region is preferably switched based on a signal and a voltage supplied from the extraction electrode power source.

  Moreover, it is preferable that the driving method of the image display device according to the present embodiment switches the emitter region in accordance with the change in the luminance signal.

  Further, when the luminance signal rises, electrons are emitted only from an emitter region formed on the side opposite to the scanning direction of the electron beam among the plurality of emitter regions, and when the luminance signal falls In this case, it is preferable to switch the emitter region so that electrons are emitted only from the emitter region formed in the electron beam scanning direction and the forward direction side among the plurality of emitter regions.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of an image display device 100 including the cathode ray tube device 1 according to the present embodiment, and FIG. 2 is a schematic cross-sectional view illustrating a configuration of the cathode ray tube device 1 according to the present embodiment. It is.

  As shown in FIG. 2, the cathode ray tube device 1 includes an envelope composed of a front panel 2 and a funnel 3, an electron gun 4 housed in a neck portion 3 a of the funnel 3, and an outer periphery of a cone portion of the funnel 3. And a deflection yoke 5 mounted on the surface. On the inner surface of the front panel 2 is formed a phosphor screen 6 in which blue (B), green (G), and red (R) phosphors are arranged in a stripe pattern. A shadow mask 7 is accommodated facing the phosphor screen 6. The shadow mask 7 is made of a metal plate provided with a plurality of electron beam passage holes. Three electron beams 8 (only G is shown in the figure) emitted from the electron gun 4 pass through the electron beam passage hole of the shadow mask 7 and strike a predetermined phosphor.

  The deflection yoke 5 deflects the three electron beams 8 emitted from the electron gun 4 in the horizontal and vertical directions and scans the phosphor screen 6 in the horizontal and vertical directions. The deflection yoke 5 includes a saddle type horizontal deflection coil, a toroidal vertical deflection coil, a ferrite core, and an insulating frame that insulates the horizontal deflection coil and the vertical deflection coil.

  FIG. 3 is a cross-sectional view showing the configuration of the electron gun 4. As shown in FIG. 3, the electron gun 4 includes a cathode assembly 10 (only one is shown) having three field emission electron source elements 9 arranged in the horizontal direction, and the cathode assembly 10 toward the phosphor screen. The control electrode 11 (G1), the acceleration electrode 12 (G2), the focusing electrode 13 (G3), and the final acceleration electrode 14 (G4) are sequentially arranged. Each electrode is provided with a through hole through which an electron beam which is a bundle of electrons emitted from the field emission electron source element 9 passes.

  The cathode assembly 10 includes a field emission electron source element 9, a substrate 15 on which the field emission electron source element 9 is mounted, and a plurality of power supplies for supplying a predetermined voltage to the field emission electron source element 9. A wire 16 and a metal support 17 for supporting the substrate 15 and supplying a predetermined voltage to the power supply wire 16 are provided.

  FIG. 4 is a perspective view showing the configuration of the field emission electron source element 9. The configuration of the field emission electron source element 9 corresponding to each color of R, G, and B is the same. As shown in FIG. 4, the field emission electron source element 9 includes five emitter regions E1, E2, which are substantially rectangular in shape along the scanning direction of the electron beam (horizontal direction in the present embodiment) on the substrate. E3, E4 and E5 are formed. A wiring pattern for supplying a predetermined voltage from the power supply wire 16 to the emitters and the extraction electrodes of the emitter regions E1 to E5 is formed on the substrate. In the 21-inch color cathode ray tube apparatus according to the present embodiment, the size of each of the emitter regions E1 to E5 is a region obtained by dividing the region of 0.10 mm in length and 0.14 mm in width into five. It is preferable.

  FIG. 5 is an enlarged perspective sectional view of a part of the emitter region. A positive constant voltage Vex is applied to the extraction electrode 18 in each of the emitter regions E1 to E5, and a voltage Vem lower than the voltage Vex is applied to the cone-shaped emitter 19. As the voltage difference between the voltage Vex and the voltage Vem increases, the amount of electrons emitted from the emitter 19 increases. Conversely, when this voltage difference becomes small (the voltage Vem approaches the voltage Vex), the amount of electrons emitted from the emitter 19 decreases. The voltage at which electrons are no longer emitted is called the cut-off voltage Vemc.

  Referring to FIG. 1 again, the image display apparatus 100 includes a drive circuit 101. The drive circuit 101 includes a drive circuit 102, a speed modulation circuit 103, a switching signal generation circuit 104, an emitter switching circuit 105, and an extraction electrode power source 106.

  The drive circuit 102 converts the luminance signal and the color signal as the video signal into the emitter voltage Vem for each of the field emission electron source elements of R, G, and B, and applies it to the emitter of each field emission type electron source element. Supply.

  The speed modulation circuit 103 converts the luminance signal into a change amount of luminance per unit time and supplies it to the switching signal generation circuit 104.

  The switching signal generation circuit 104 outputs an emitter switching signal to the emitter switching circuit 105 when the amount of change in luminance per time supplied from the speed modulation circuit 103 is the amount of change when the luminance signal rises or falls. Is.

  The extraction electrode power supply 106 supplies a predetermined voltage to the emitter switching circuit 105. The emitter switching circuit 105 switches the emitter region that emits electrons among the emitter regions E1 to E5 based on the emitter switching signal output from the switching signal generation circuit 104 and a predetermined voltage supplied from the extraction electrode power source 106. Is to do.

  Operations of the image display apparatus 100 and the cathode ray tube apparatus 1 configured as described above will be described.

  6 is a schematic diagram for explaining the operation of the electron beam 8 emitted from the electron gun 4. FIGS. 7 to 9 are schematic diagrams for explaining the operation of the emitter region that emits the electron beam. .

  As shown in FIG. 6, the electrons emitted from the field emission electron source element of the cathode structure are bundled into an electron beam 8 (only one is shown), and the electron beam 8 is a plurality of electrodes constituting the electron gun 4. It is emitted from the electron gun 4 while receiving the electric field lens action. The three electron beams 8 emitted from the electron gun 4 are deflected by the deflection yoke 5, pass through the electron beam passage hole of the shadow mask 7, and strike a predetermined phosphor on the phosphor screen 6. Thereby, a color image is displayed.

  Next, a driving method for switching the electron emission states of the emitter regions E1 to E5 will be described with reference to FIGS. In the figure, hatched emitter regions indicate emitter regions from which electrons are emitted.

  As shown in FIG. 7, during normal operation in which the luminance signal does not change, only the emitter regions E2 to E4 formed near the center of the entire emitter regions E1 to E5 are driven by the emitter switching circuit 105 (FIG. 1). The constant voltage Vex is applied to the emitter regions E2 to E4 near the center, and a zero volt voltage is applied to the emitter regions E1 and E5 at both ends. Therefore, in this case, electrons are emitted only from the emitter regions E2 to E4 near the center, and electrons are not emitted from the other emitter regions E1 and E5 at both ends.

  As shown in FIG. 8, when the luminance signal rises, that is, when the luminance level changes from black to white, the emitter switching circuit 105 causes the emitter regions E1 to E5 in the entire direction opposite to the beam scanning direction. The emitter regions E1 to E3 formed in the above are switched so as to be driven, a constant voltage Vex is applied to the emitter regions E1 to E3, and the emitter regions E4 and E5 formed from the beam scanning direction and the forward direction side Apply a voltage of zero volts. As a result, electrons are emitted only from the emitter regions E1 to E3, and no electrons are emitted from the other emitter regions E4 and E5.

  As shown in FIGS. 7 to 9, the central emitter region E3 is driven so as to always emit electrons.

  As described above, when electrons are emitted only from the emitter regions E1 to E3 formed from the direction opposite to the beam scanning direction, the beam spot on the phosphor screen 6 is positioned at the time of normal operation shown in FIG. Shifts in the beam scanning direction and forward direction. That is, the effect that the beam spot advances in the beam scanning direction can be obtained.

  As shown in FIG. 9, when the luminance signal falls, that is, when the luminance level changes from the white side to the black side, the emitter switching circuit 105 causes the emitter regions E1 to E5 to be scanned in the beam scanning direction and the forward direction. Switching is made so that only the emitter regions E3 to E5 formed from the side are driven, a constant voltage Vex is applied to the emitter regions E3 to E5, and the emitter regions E1 and E2 formed from the side opposite to the beam scanning direction A voltage of zero volts is applied to. As a result, electrons are emitted only from the emitter regions E3 to E5, and no electrons are emitted from the other emitter regions E1 and E2.

  As described above, when electrons are emitted only from the emitter regions E3 to E5 formed from the beam scanning direction and the forward direction side, the beam spot on the phosphor screen 6 is located at the normal operation position shown in FIG. On the other hand, it shifts in the direction opposite to the beam scanning direction. That is, the effect that the beam spot moves backward with respect to the beam scanning direction can be obtained.

  FIG. 10 shows the beam spot of the electron beam generated by the electrons emitted from three of the five emitter regions and the luminance level of the luminance signal input to the cathode ray tube device 1 (white and black are shown for convenience). And the output (brightness) of the beam spot on the phosphor screen. An arrow A in the figure indicates the scanning direction of the electron beam.

  The upper graph in FIG. 10 shows the relationship between the luminance level of the luminance signal and time. The middle diagram of FIG. 10 schematically shows the relationship between the beam spot of the electron beam, which changes by switching the emitter region from which electrons are emitted by the emitter switching circuit 105, and time. The lower graph in FIG. 10 shows the relationship between the beam spot output (brightness) and time.

  As shown in FIG. 10, at time T1 when the luminance level changes from the black side to the white side (at the rising edge of the luminance signal), the voltage in the “forward” state is applied to the field emission electron source element 9 from the emitter switching circuit 105. Supplied. For this reason, the beam spot 31 on the phosphor screen 6 is shifted to a position advanced from the normal movement position in the scanning direction and forward direction of the electron beam indicated by the arrow A.

  At the time T2 when the luminance level changes from the white side to the black side (at the falling edge of the luminance signal), the voltage in the “retreat” state is supplied from the emitter switching circuit 105 to the field emission electron source element 9. For this reason, the beam spot 32 on the phosphor screen 6 is shifted to a position retracted from the normal movement position in the direction opposite to the scanning direction of the electron beam indicated by the arrow A.

  Due to the movement of the position of the beam spot, the brightness output (brightness) drawn on the phosphor screen has a region 33 brighter than the normal brightness in the white region, and the white side in the black region. A region 34 darker than the normal brightness is generated before and after this region. Such an effect is substantially the same as the effect obtained by the speed modulation of the prior art described above. Therefore, according to the present embodiment, the effect of velocity modulation can be obtained without providing a magnetic field generator externally as in the prior art.

  Furthermore, the image display apparatus and the cathode ray tube apparatus according to the present embodiment can also achieve the effects described below.

  In the speed modulation of the prior art, since the electron beam is moved with respect to the magnetic field, eddy current loss is caused by the metal structure of the electron gun that generates the electron beam. For this reason, the magnetic field for moving the electron beam was weakened, and it was impossible to follow the fast movement of the electron beam, and fine velocity modulation could not be performed.

  On the other hand, in this embodiment, since it is not necessary to provide a magnetic field generator, eddy current loss does not occur. For this reason, it is possible to follow the movement of the fast electron beam, and fine speed modulation is possible. Furthermore, since it is possible to follow a minute change in the high-frequency luminance signal, fine speed modulation can be performed even if the luminance signal has a high frequency.

  As described above, in the present embodiment, the number of emitter regions formed in the field emission electron source element is five. However, the number is not limited to this, and a plurality of five or more may be formed.

  The present invention can be applied to a cathode ray tube apparatus provided with speed modulation means for delaying and accelerating an electron beam emitted from an electron gun along a scanning direction.

Block diagram showing a configuration of an image display device according to the present embodiment Schematic sectional view showing the configuration of a cathode ray tube device provided in the image display device according to the present embodiment Sectional drawing which shows the structure of the electron gun provided in the cathode ray tube apparatus which concerns on this Embodiment The perspective view which shows the structure of the field emission type electron source element provided in the electron gun concerning this Embodiment Sectional perspective view enlarging a part of the emitter region according to the present embodiment Schematic diagram for explaining the operation of the electron beam emitted from the electron gun according to the present embodiment Schematic diagram showing the operation of the emitter region that emits electrons according to the present embodiment Schematic diagram showing the operation of the emitter region that emits electrons according to the present embodiment Schematic diagram showing the operation of the emitter region that emits electrons according to the present embodiment The figure which shows the relationship between the beam spot formed in the fluorescent screen of the cathode ray tube apparatus which concerns on this Embodiment, the luminance level of a luminance signal, and the output (brightness) of the beam spot formed in a fluorescent screen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cathode ray tube apparatus 100 Image display apparatus 101 Drive circuit 102 Drive circuit 103 Speed modulation circuit 104 Switching signal generation circuit 105 Emitter switching circuit 106 Extraction electrode power supply E1, E2, E3, E4, E5 Emitter area

Claims (10)

An electron gun that is housed in the neck of the funnel and emits an electron beam;
A cathode ray tube device mounted on an outer peripheral surface of the funnel and provided with a deflection yoke for deflecting the electron beam;
The electron gun includes a field emission electron source element in which a plurality of emitter regions for emitting electrons are formed,
The plurality of emitter regions are formed along a scanning direction of the electron beam,
A cathode-ray tube apparatus characterized in that an emitter region that emits electrons and an emitter region that does not emit electrons are switched among the plurality of emitter regions.   2. The cathode ray tube apparatus according to claim 1, wherein the emitter region is switched in accordance with a change in luminance signal. At the time of rising of the luminance signal, electrons are emitted only from the emitter region formed on the side opposite to the scanning direction of the electron beam among the plurality of emitter regions,
When the luminance signal falls, the emitter region is switched so that electrons are emitted only from the emitter region formed from the scanning direction and the forward direction side of the electron beam among the plurality of emitter regions. 3. A cathode ray tube apparatus according to claim 2, wherein:   4. The cathode ray tube apparatus according to claim 3, wherein at least five of the plurality of emitter regions are formed.   5. The cathode ray tube apparatus according to claim 4, wherein electrons are always emitted from a central emitter region among the five emitter regions. A cathode ray tube device according to any one of claims 2 to 5,
An image display device comprising: an emitter switching circuit for switching the emitter region. A speed modulation circuit for converting the luminance signal into a change amount per unit time;
A switching signal generating circuit that outputs an emitter switching signal to the emitter switching circuit when the variation obtained by the speed modulation circuit is a variation at the rising or falling of the luminance signal;
An extraction electrode power supply for supplying a voltage to the emitter switching circuit;
7. The emitter switching circuit switches the emitter region based on the emitter switching signal output from the switching signal generation circuit and a voltage supplied from the extraction electrode power source. Image display device. A cathode ray tube device having an electron gun having a field emission electron source element in which a plurality of emitter regions for emitting electrons are formed along the scanning direction of the electron beam; and a deflection yoke for deflecting the electron beam;
A speed modulation circuit that converts a luminance signal into a change amount per unit time; and
A switching signal generation circuit that outputs an emitter switching signal to the emitter switching circuit when the amount of change obtained by the speed modulation circuit is a variation at the time of rising or falling of the luminance signal;
An extraction electrode power supply for supplying a voltage to the emitter switching circuit;
Based on the emitter switching signal output from the switching signal generation circuit and the voltage supplied from the extraction electrode power supply, an emitter region that emits electrons and an emitter region that does not emit electrons, of the plurality of emitter regions. A method for driving an image display device, wherein switching is performed.   9. The method for driving an image display device according to claim 8, wherein the emitter region is switched in accordance with a change in the luminance signal. At the time of rising of the luminance signal, electrons are emitted only from the emitter region formed on the side opposite to the scanning direction of the electron beam among the plurality of emitter regions,
When the luminance signal falls, the emitter region is switched so that electrons are emitted only from the emitter region formed from the scanning direction and the forward direction side of the electron beam among the plurality of emitter regions. The method for driving an image display device according to claim 9.

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