JP2000352949A - Crt display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a CRT display, in which display power consumption is minimized when display luminance is reduced for energy conservation, by changing the speed of electron beams in a multistage manner and accordingly changing the magnitude of a deflection current maximum value. SOLUTION: A high voltage circuit 4 generates anode, screen and focus voltages so that the speed of electron beams produces a luminance level requested by the driving power supply voltage from a power supply circuit 5. A deflection circuit 1 generates a deflection current having a deflection current maximum value corresponding to the electron beam speed by the driving power supply voltage from the circuit 5. A deflection coil 2 generates deflection magnetic field corresponding to the electron beam speed by the deflection current from the circuit 1. An electron gun 3 emits electron beams with the requested electron beam speed and focus by the anode, screen and focus voltages from the circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT display and relates to a CRT display, in which the acceleration voltage of an electron beam is changed in multiple stages to change the speed of the electron beam, thereby changing the maximum deflection current, thereby reducing the power consumption of the display. And power control of a display for switching the display.

[0002]

2. Description of the Related Art Demand for personal computers has begun to increase year by year, and accordingly, demand for personal computer displays has also increased. PC displays are strongly required to save power due to the ecology mind that is increasing in recent years, and it is necessary to satisfy this.

A personal computer in an office or the like often remains powered on during working hours. When a user is not using the personal computer, the power of the personal computer display may be turned off, but the display is always required. Sometimes. As a power saving method at this time, the usual method is to keep the display brightness low.

For example, as disclosed in Japanese Patent Application Laid-Open No. 5-6146, it is common to reduce the amount of electron beams in order to suppress the brightness of a CRT display.

[0005] Recently, one system for realizing power saving of a personal computer display using a CRT display has been proposed. This suppresses the electron beam speed of the cathode ray tube lower than before, thereby reducing the magnitude of the deflection magnetic field of the deflection coil. When the electron beam speed is suppressed, the display becomes darker, but the focus of the electron beam is reduced, and the brightness is restored using a special cathode ray tube accompanying the focus.

[0006]

In the above conventional example, the amount of the electron beam of the CRT display is adjusted in order to obtain the optimum brightness, and the power saving in which the speed of the electron beam is adjusted is specifically described. Did not.

[0007] In a recently devised CRT display which further reduces the electron beam speed to improve the power saving effect, a special display tube is formed to restore the brightness. However, when adjusting the brightness, the cathode current is changed by changing the amount of the electron beam instead of changing the electron beam speed in multiple stages. Therefore, even in a display that does not require a large amount of brightness as in the power saving mode, the brightness is suppressed by reducing only the amount of the electron beam.

An object of the present invention is to change the speed of an electron beam in multiple steps, and also to change the magnitude of the maximum value of the deflection current in accordance with the change, so that the display brightness when the display brightness is reduced by power saving or the like is reduced. C to minimize power consumption
It is to provide an RT display.

[0009]

In order to solve the above problems, in a CRT display, a high voltage circuit for generating an acceleration voltage capable of switching the speed of an electron beam in multiple stages, and a high voltage circuit according to the speed of the electron beam. A deflection circuit for switching the deflection current maximum value in multiple stages, and switching the power consumption of the display by changing the speed of the electron beam.

When the speed of the electron beam changes, the focus voltage, the screen voltage, or the amplitude of the side pin correction waveform is switched in multiple stages.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. According to a first embodiment of the present invention, a deflection circuit 1 for receiving a synchronization signal and outputting a deflection current to a deflection coil, a deflection coil 2 for generating a deflection magnetic field by the deflection current from the deflection circuit 1, a screen voltage and an anode An electron gun 3 for generating an electron beam by receiving a voltage and a focus voltage, a high voltage circuit 4 for generating a screen voltage, an anode voltage and a focus on the electron gun 3 by a signal from the deflection circuit 1;
A power supply circuit 5 for supplying a driving power supply voltage to the high-voltage circuit 4 and the deflection circuit 1, and a control signal to the power supply circuit 5,
A control circuit 6 for sending a screen voltage signal to the high voltage circuit 4
And an interface circuit 7 for notifying the control circuit 6 that the power consumption has changed.

Next, the operation will be described. A display luminance signal of the cathode ray tube 8 is input to the interface circuit 7, and the interface circuit 7 outputs a signal corresponding to a luminance level requested by a user or a luminance control system to the control circuit 6. The control circuit 6 sends, for example, a PWM signal to the power supply circuit 5. The power supply circuit 5 generates a drive power supply voltage based on the received PWM signal. The high-voltage circuit 4 generates an anode voltage, a screen voltage, and a focus voltage for generating an electron beam speed such that the luminance level required by the driving power supply voltage from the power supply circuit 5 is obtained. The deflection circuit 1 generates a deflection current having a deflection current maximum value corresponding to the electron beam speed by the drive power supply voltage from the power supply circuit 5. The deflecting coil 2 generates a deflecting magnetic field according to the electron beam speed by the deflecting current from the deflecting circuit 1. Electron gun 3
Emits an electron beam at a required electron beam speed and focus by the anode voltage, screen voltage and focus voltage from the high voltage circuit 4.

These operations are based on the following principle. Kinetic energy of electron beam and brightness L of cathode ray tube
Is in a proportional relationship. Further, the magnitude of the deflection magnetic field B and the rotation radius r of the electron beam are in inverse proportion. further,
The deflection current IP and the deflection magnetic field B are in a proportional relationship. These are shown in the equations as follows.

[0014]

(Equation 1)

[0015]

(Equation 2)

[0016]

(Equation 3)

[0017]

(Equation 4)

Here, L is the brightness of the cathode ray tube, m is the mass of the electron, v is the speed of the electron, r is the radius of rotation of the electron due to the deflection magnetic field, q is the charge, B is the magnitude of the deflection magnetic field, and IP is the deflection current. , N is the number of electrons in the electron beam.

According to the equations (1) and (2), the number n of electrons or the electron beam velocity v may be reduced in order to reduce the luminance L. In the present invention, however, attention is paid to the electron beam velocity v. When the electron beam speed v is reduced, the luminance L decreases according to (1). According to the equation (3), when the electron beam speed v decreases, the rotation radius r of the electron beam is constant, so that the deflection magnetic field B decreases in proportion to the electron beam speed v.

From equation (4), as the deflection magnetic field B decreases, the deflection current IP also decreases. For example, the distribution of power consumption of a CRT display is such that deflection power is 40%, electron beam power is 30%.
% And other 30%. When the magnitude L of the luminance is reduced to half, the velocity v of the electron beam becomes half the route and the turning radius r is constant, so that the deflection magnetic field B also becomes one half the route.
And the deflection current IP also decreases.

Then, the deflection power becomes about 28% in the original route half, and the electron beam power also becomes 15% of the half, so that the whole power is compared before the luminance L is reduced. About 73%. This saves 12% of power compared to simply reducing the number n of electrons in the electron beam by half (85%). The degree of this saving becomes remarkable as the power ratio of the deflection magnetic field B increases.

FIG. 2 shows an example of the deflection circuit 1 and the high voltage circuit 4. The deflection circuit 1 includes a synchronization circuit 9, a vertical oscillation circuit 10, a vertical drive circuit 11, a vertical output circuit 12, and a horizontal AFC circuit 1.
3, a horizontal oscillation circuit 14, a horizontal drive circuit 15, and a horizontal output circuit 16. The synchronization circuit 9 receives the synchronization signal and outputs a vertically and horizontally separated synchronization signal to the vertical oscillation circuit 10 and the horizontal AFC circuit 13. Vertical oscillation circuit 1
0 outputs a waveform-shaped synchronization signal to the vertical drive circuit 11. In the vertical drive circuit 11, the vertical output circuit 12
And outputs a drive signal that has been amplified and waveform shaped. The vertical output circuit 12 receives the drive power supply voltage from the power supply circuit 5, outputs a deflection current having a maximum value according to the drive power supply voltage, and outputs a side pin correction signal to the horizontal output circuit according to the drive power supply voltage.

The horizontal AFC circuit 13 receives a flyback pulse from the high voltage circuit 4 and a horizontal synchronization signal from the synchronization circuit 9, performs waveform shaping and phase adjustment of the synchronization signal, and outputs a synchronization signal to the horizontal oscillation circuit 14. . Horizontal oscillation circuit 14
Outputs a drive signal for the horizontal drive circuit 15 in response to a synchronization signal from the horizontal AFC circuit 13. Horizontal drive circuit 1
5 outputs the amplified drive signal to the horizontal output circuit 16. The horizontal output circuit 16 outputs a deflection current according to the driving voltage from the power supply circuit 5 to the deflection coil 2. High voltage circuit 4
Is mainly composed of a flyback transformer 17 and generates an anode voltage and a focus voltage by a drive power supply voltage from the power supply circuit 5 so that the electron beam speed specified by the control circuit 6 is obtained. The flyback transformer 17 outputs a flyback pulse to the horizontal AFC circuit 13.

FIG. 3 is an example of a deflection current waveform. This shows that the maximum value of the triangular waveform changes when the drive power supply voltage of the vertical output circuit 12 and the horizontal output circuit 16 changes. As the electron beam velocity decreases, the maximum value of the deflection magnetic field also decreases, so the maximum value of the triangular waveform decreases.

[0025]

When the brightness of the CRT display is reduced in the power saving mode by using the present invention, the maximum value of the deflection magnetic field is reduced at the same time by changing the electron beam speed small. This method consumes less power than a method of saving power by reducing the number of electrons in the electron beam.

Further, when the speed of the electron beam changes, the deterioration of the image quality is corrected by switching the amplitude of the focus voltage, the screen voltage or the side pin correction waveform in multiple stages.

[Brief description of the drawings]

FIG. 1 is a block diagram of a CRT display according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a CRT display as an example of a deflection circuit and a high voltage circuit.

FIG. 3 is a characteristic diagram showing an example of a deflection current waveform.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Deflection circuit, 2 ... Deflection coil, 3 ... Electron gun, 4 ... High voltage circuit, 5 ... Power supply circuit, 6 ... Control circuit, 7 ... Interface, 8 ... CRT, 9 ... Synchronization circuit, 10 ... Vertical oscillation circuit, 11 ... vertical drive circuit, 12 ... vertical output circuit,
13 ... horizontal AFC circuit, 14 ... horizontal oscillation circuit, 15 ... horizontal drive circuit, 16 ... horizontal output circuit, 17 ... flyback transformer, 18 ... video circuit.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 5C058 AA01 BA26 BA27 CA08 CA09 5C068 AA06 BA02 BA12 CB01 HB03 HB04 JA03 MA05

Claims (4)

[Claims] In a CRT display, a high voltage circuit for generating an acceleration voltage capable of switching an electron beam speed in multiple stages, and a deflection capable of switching a deflection current maximum value in multiple stages according to the electron beam speed. And a circuit, wherein the power consumption of the display is switched by changing the speed of the electron beam. 2. The CRT display according to claim 1, wherein the focus voltage is switched in multiple stages when the speed of the electron beam changes. 3. The CRT display according to claim 1, wherein the screen voltage is switched in multiple stages when the speed of the electron beam changes. 4. The CRT display according to claim 1, wherein the amplitude of the side pin correction waveform is switched in multiple stages when the speed of the electron beam changes.