JP2008084658A - Field emission lamp and its drive method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow uniform light emission by suppressing light emission flicker of a phosphor, to enhance emission efficiency by improving luminance, to suppress rise of a tube surface temperature, and to facilitate manufacturing. <P>SOLUTION: This field emission lamp 10 is composed by arranging a positive electrode 18 with a phosphor 16 in a planar form oppositely to a field electron emitter 20, and an electron lens means 25 periodically converging and diverging electrons emitted from the field electron emitter 20 is arranged between the field electron emitter 20 and the positive electrode 18. In this electron lens means 25, at least two gate electrodes 26 and 28 each having a plurality of are arranged oppositely to each other in parallel to each other and at a certain distance. In its drive method, orbits of the electrons from the field electron emitter 20 are repeatedly converged and diverged by both the gate electrodes 26 and 28 by applying an A.C. voltage between both the gate electrodes 26 and 28 to scan/control positions at which the phosphor 16 is irradiated with the electrons. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a field emission lamp (including a field emission display) that emits electrons from a field electron emitter by an electric field and emits the electrons by applying the electrons to the phosphor, and a driving method of the field emission lamp. is there.

  As a driving method of the field emission lamp, a positive voltage of a direct current power source is applied to the anode side, and electrons are emitted from each of a large number of electron emission points on the field electron emitter toward the anode by electric field concentration, and this emission is performed. Electrons collide with the phosphor on the anode to cause the phosphor to excite and emit light (Patent Document 1).

  In such a driving method, as indicated by d1 → d2 → d3 →... In FIG. 8, the areas indicated by the bright white circles that have been excited and emitted so far correspond to the respective emission areas of the phosphor, and become darker. A region indicated by another black circle that has been dark until then is excited to emit light and become brighter.

  As described above, in the conventional driving method, light and dark flickering, that is, light emission that consists of a set of a large number of bright and dark spots indicated by the above-described white and black spots, and the set state of the bright and dark spots is not fixed and changes randomly and randomly. A condition has occurred.

In addition, the presence of dark areas also affects the magnitude of luminance. Furthermore, energy that does not contribute to light emission changes to heat, and the temperature of the field emission lamp becomes extremely high, making it difficult to handle the field emission lamp and causing large energy loss.
JP 2002-343279 A

  The problem to be solved by the present invention is that it is possible to uniformly emit light by suppressing the light emission flicker of the phosphor, to improve the luminance and increase the light emission efficiency, to suppress the increase in the tube surface temperature, and to be easily manufactured It is possible to achieve

  A field emission lamp according to the present invention is a field emission lamp in which an anode with a phosphor is arranged in a plane to face a field electron emitter, and the phosphor is excited by light emitted from electrons emitted from the field electron emitter. An electron lens means for periodically converging and emitting electrons emitted from the field electron emitter is disposed between the field electron emitter and the anode.

  Preferably, the electron lens means comprises at least two gate electrodes having a plurality of electron passage holes disposed between the field electron emitter and the anode.

  In the present invention, the phosphor can emit light in a plurality of regions by electrons emitted from a large number of electron emission points provided in the field electron emitter. In this case, electrons from a large number of electron emission points of the field electron emitter are periodically converged and diverged by the electron lens means, and the position where the phosphor is irradiated is scanned. For this reason, the light emission spot of the phosphor that emits light by being irradiated with a large number of electrons emitted from the field electron emitter is scanned, so that the light emission flicker does not occur in all of the light emission spots of the phosphor. Spots are eliminated, and an overall soft and uniform light emission state can be obtained.

  In addition, according to the present invention, since the dark spots are eliminated, the overall luminance is improved and the luminous efficiency can be increased.

  Furthermore, according to the present invention, the energy used for electron emission can be made to contribute almost to light emission, and accordingly, the high temperature of the field emission lamp is eliminated and it becomes easy to handle, and the energy consumption loss can be reduced.

  The field emission lamp driving method according to the present invention is characterized in that an AC voltage is applied between the gate electrodes to irradiate electrons from a field electron emitter on the phosphor screen of the phosphor. .

  In the above, it is preferable to set the frequency of the AC voltage to a frequency exceeding 50-60 Hz. More preferably, it is 100 Hz to 120 Hz which is twice the commercial power supply frequency.

  In the drive system of the present invention, by setting the frequency of the AC voltage to a frequency exceeding 50-60 Hz, the frequency of repetition of convergence and divergence of electrons is the limit of the frequency response that can be perceived visually by humans. Therefore, it is preferable that the flickering of the phosphor is eliminated.

  According to the present invention, it is possible to emit light uniformly by suppressing the light emission flicker of the phosphor, improve the overall luminance, and greatly increase the light emission efficiency.

  Hereinafter, a field emission lamp and a driving method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  1 is a side view of the field emission lamp of the embodiment, FIG. 2 is an exploded perspective view of the field emission lamp of FIG. 1, and FIGS. 3A, 3B, and 3C are drive voltages of the field emission lamp. FIGS. 4 to 7 are diagrams showing respective waveforms, and FIGS. 4 to 7 are diagrams showing an electron scanning state and a light emission state from the front panel for explaining the driving of the field emission lamp.

  1 and 2, reference numeral 10 denotes a field emission lamp (which may be referred to as a field emission display in the embodiment), and this field emission lamp 10 is a flat plate on the light emission side and is made of a glass plate. The interior is composed of a transparent front panel 12, a flat rear panel 14 arranged in parallel on the back side, and a frame-shaped side panel (not shown) in which the peripheral portions of the front panel 12 and the rear panel 14 are disposed between each other. This is a vacuum-sealed front panel type. An anode 18 with a phosphor 16 is formed on the inner surface of the front panel 12. The term “transparent” means that light can be transmitted and is not limited to the transmittance.

  The phosphor 16 is a phosphor that emits light by excitation when irradiated with electrons. The phosphor 16 emits visible light when excited by electron irradiation. The phosphor 16 may be a known phosphor and is not particularly limited. The phosphor 16 can be formed on the anode 18 by a slurry coating method, a screen printing method, an electric perturbation method, a sedimentation method, or the like. The anode 18 is formed of a transparent conductive film such as ITO (indium tin oxide) or aluminum in a thin film shape by sputtering, EB vapor deposition, or the like.

  On the inner surface of the rear panel 14, a plurality of field electron emitters 20 extend in parallel to each other in a wire shape and are arranged in parallel at equal intervals. The field electron emitter 20 has a large number of electron emission points made of fine protrusions in the order of nm made of a carbon film on the outer periphery of the conducting wire. This electron emission point is composed of carbon nanotubes, carbon nanowalls, needle-like carbon films, and the like, and emits electrons when electric fields are concentrated on the tips of minute protrusions. DC power supplies 22 and 24 are connected between the anode 18 and the plurality of field electron emitters 20.

  In the above configuration, the field emission lamp 10 of the embodiment is characterized in that the electron lens means 25 is arranged between the field electron emitter 20 and the anode 18.

 This electron lens means 25 is configured by arranging at least two gate electrodes 26, 28 having a plurality of electron passage holes 26a, 28a in parallel and spaced from each other.

When the field emission lamp 10 is driven, an AC voltage from an AC power source 30 is applied between the gate electrodes 26 and 28 of the electron lens means 25, and the trajectory of the electrons P emitted from the field electron emitter 20 is changed to the both gates. The position of irradiating the phosphor 16 with the electrons P is controlled by repeating convergence and divergence by the electrodes 26 and 28, respectively. The magnitude of this AC voltage is not limited and is about 100V to several It may be about kV or 100V or less. The magnitude of this AC voltage can be adjustable. The waveform of the AC voltage is not particularly limited. For example, as shown in FIGS. 3A to 3C, a sine wave (FIG. 3A), a rectangular wave (FIG. 3B), a rectangular wave including a ripple ( A waveform such as that shown in FIG.

  The driving of the field emission lamp 10 will be described with reference to FIGS. 4 (a), 4 (b), and 4 (c). P in the figure represents electrons. The drive waveform in FIG. 4 is a sine wave.

  First, in FIG. 4A, the AC voltage of the AC power source 30 is zero, and both gate electrodes 26 and 28 are at the same potential, so that the electrons P from the field electron emitter 20 pass through the gate electrodes 26 and 28. When passing through the holes 26a, 28a, it does not converge or diverge, and travels almost straight toward the anode 18 without being bent.

  Then, next, as shown in FIG. 4B, a positive voltage is applied to the upper gate electrode 26 on the side close to the anode 18 of both gate electrodes 26 and 28, and the lower gate on the side close to the field electron emitter 20. When a negative voltage is applied to the electrode 28, the entire gate electrode 26, 28 is omitted in detail, but the trajectory is bent so that the electron P from the field electron emitter 20 functions as an electron focusing lens and is converged. And proceed toward the anode 18.

  When a negative voltage is applied to the upper gate electrode 26 and a positive voltage is applied to the lower gate electrode 28, as shown in FIG. The electron P from the field electron emitter 20 fulfills the function of a lens, and the trajectory is bent so that the electron P is diverged and travels toward the anode 18.

  As a result of the above, the electrons P from the field electron emitter 20 converge and diverge so that the region of the phosphor 16 is evenly irradiated, and the repetition frequency of the convergence and divergence is set by the human by the frequency setting of the AC power supply 30. Since the high frequency exceeding the limit of the frequency response that can be sensed visually, for example, about 50 Hz to 60 Hz or more, and preferably 100 Hz to 120 Hz, the phosphor 16 is visually perceived as having no light emission flicker in humans. As a result, the phosphor 16 is in a uniform light emission state.

  Therefore, the front panel 12 emits light as indicated by d 1 → d 2 → d 1 → d 3 → d 1 → d 2... In FIG. Here, d1 corresponds to FIG. 4 (a), d2 corresponds to FIG. 4 (b), and d3 corresponds to FIG. 4 (c). In this case, since the state of d1 is a short period at the above repetition frequency of convergence and divergence, in human vision, as shown in FIG. 5B, the whole is a bright region, and the luminance changes brightly and darkly as in the past. There is no light emission, and light can be emitted with substantially uniform brightness as a whole, and light emission flicker is eliminated.

  Next, when the waveform of the drive voltage is a rectangular wave, electrons converge and diverge as shown in FIGS. 6 (a) and 6 (b). Due to the convergence and divergence of the electrons, the light emission of the front panel 12 becomes as indicated by d 1 → d 2 → d 1 → d 2... In FIG. 7 (a). It becomes a bright area, does not change in brightness brightly and darkly as in the prior art, and can emit light with substantially uniform brightness as a whole, eliminating light emission flicker.

  As described above, in this embodiment, the entire luminance change is reduced, and it can be driven to a soft and uniform light emission state, and a field emission lamp suitable for use as an illumination lamp can be provided. . In addition, although it was the front panel type of embodiment, a tubular type may be sufficient.

  The present invention is not limited to the above-described embodiments, and includes various changes or modifications within the scope described in the claims.

FIG. 1 is a side view of the field emission lamp of the embodiment. FIG. 2 is an exploded perspective view showing the field emission lamp of FIG. FIG. 3 shows each waveform of the drive voltage of the field emission lamp. FIG. 4 is a diagram showing an electron trajectory when a sinusoidal drive voltage is applied to the gate electrode. FIG. 5A is a view showing a light emission state of the field emission lamp by the electron trajectory of FIG. 4, and FIG. 5B is a view showing a light emission state when the front panel is viewed on human vision. FIG. 6 is a diagram showing an electron trajectory when a rectangular wave voltage is applied to the gate electrode. FIG. 7A is a view showing a light emission state of the field emission lamp by the electron trajectory of FIG. 6, and FIG. 7B is a view showing a light emission state when the front panel is viewed on human vision. FIG. 8 is a diagram for explaining a conventional field emission lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Field emission lamp 12 Front panel 14 Rear panel 16 Phosphor 18 Anode 20 Field electron emitter 22, 24 DC power supply 25 Electron lens means 26 Upper gate electrode 28 Lower gate electrode 30 AC power supply

Claims (4)

In a field emission lamp in which an anode with a phosphor is disposed in a plane opposite to a field electron emitter, and the phosphor is excited to emit light upon irradiation with electrons emitted from the field electron emitter.
A field emission lamp characterized in that an electron lens means for periodically converging and emitting electrons emitted from the field electron emitter is disposed between the field electron emitter and the anode.   2. The field emission lamp according to claim 1, wherein the electron lens means comprises at least two gate electrodes having a plurality of electron passage holes disposed between the field electron emitter and the anode. . In the drive system of the field emission lamp of Claim 1 or 2,
A driving method for a field emission lamp, wherein an AC voltage is applied between the gate electrodes to irradiate electrons from a field electron emitter onto the phosphor screen of the phosphor.   4. The field emission lamp driving system according to claim 3, wherein the frequency of the AC voltage is set to a frequency exceeding 50-60 Hz.

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