JP2005049651A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which can turn off power source supply from an external power source to a main power source in a power save mode, and by which electric power consumption can be eliminated. <P>SOLUTION: The display device is equipped with a connection interface 2 which is connectable to a host apparatus 90, a video display part 4 which displays videos based on a video signal and synchronization signal inputted via the connection interface 2, the main power source 12 which supplies the power source from the external power source to the video display part 4, a power source switch 14 which turns on/off the power source supply to the main power source 12, and power save control circuits 10 and 6. The power save control circuits 10 and 6 are are arranged to be driven by a circuit power source supplied via the connection interface 2 and are so arranged as to shut off the power source supply to the main power source 12 by turning off the power source switch 14 when there is no more input from the synchronization signal via the connection interface 2 and to supply the power source to the main power source 12 by turning on the power source switch 14 when the synchronization signal is inputted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is connected to a host device such as a personal computer, displays a video based on a video signal and a synchronization signal input from the host device, and displays a monitor or the like that enters a power save mode based on the presence or absence of the synchronization signal. It relates to the device.

  Conventionally, when a host device such as a personal computer shifts to the power save mode and a synchronization signal (one or both of horizontal and vertical synchronization signals) is not input from the host device to the display device, a video display unit such as a liquid crystal display There is a display device that stops the power supply to the device and shifts to a power saving mode for reducing power consumption.

  Patent Literature 1 describes one of conventional liquid crystal display devices having a function of shifting to a power save mode.

The liquid crystal display device 1 described in Patent Document 1 is for converting an analog signal from the liquid crystal panel 4 and the PC 11 into a digital signal for display on the liquid crystal panel 4 by a power supply circuit 4 connected to an AC input port 12. Power is supplied to the signal processing circuit 2 and the inverter circuit 3 that controls the backlight of the liquid crystal panel 4 (FIG. 3, paragraph 0024).
The standby power supply 7 connected to the AC input port 12 supplies power to the control microcomputer 6 and the restart signal generation circuit 13 (FIG. 3, paragraph 0027).

When the liquid crystal display device 1 described in Patent Document 1 detects that the horizontal synchronization signal and / or the vertical synchronization signal is no longer input from the PC 11, the control microcomputer 6 turns off the switch 5, and each circuit ( The power supply to the signal processing circuit 2, the inverter circuit 3, and the liquid crystal panel 4) is cut off (paragraph 0028), and the transmission circuit 9 in the control microcomputer 6 is stopped (paragraph 0031).
The horizontal / vertical synchronization signal from the PC 11 is detected by the restart signal generation circuit 13. When the horizontal / vertical synchronization signal is detected, the control microcomputer 6 is restarted by the interrupt signal from the restart signal generation circuit 13. The switch 5 is turned on by the control microcomputer 6 to supply power to each circuit (signal processing circuit 2, inverter circuit 3, and liquid crystal panel 4), and display an image on the liquid crystal panel 4 (normal operation state) (paragraph 0033- 0035).

According to this, since the transmission circuit 9 can be stopped in the off state (power save mode), a display device with a high power saving effect can be provided (paragraph 0036).
Japanese Patent Laid-Open No. 2002-258811

However, in a conventional display device such as the liquid crystal display device 1 described in Patent Document 1, a control unit (control microcomputer 6 or the like that detects a signal from the host device (PC 11) for returning from the power save mode to the display mode). Since power is supplied to the restart signal generation circuit 13) by the power supply of the display device (standby power supply 7), there is a problem that the power consumption of the display device cannot be eliminated.
(So far, the reference numerals used in Patent Document 1 are used)

In order to solve the above problems, a display device according to the present invention has the following configuration. That is, a connection interface provided so as to be connectable to a host device, and a video signal and a synchronization signal of the video signal are input from the host device, and a circuit power for driving an electronic circuit is supplied from the host device; A video display unit that displays video based on the video signal and the synchronization signal input via the connection interface, a main power source that supplies power from an external power source to the video display unit, and the main power source The power switch for turning on / off the power supply of the device and the circuit power supplied via the connection interface are provided so as to be driven, and the synchronization signal is not input from the host device via the connection interface. In this case, the power switch is turned off to cut off the power supply to the main power supply and supply the power to the video display unit. And a power save control circuit for turning on the power switch to supply power to the main power supply and supplying power to the video display section when the synchronization signal is input. And
According to this, the power save control circuit that controls switching between the power save mode and the display mode by switching the power switch according to the input state of the synchronization signal is supplied from the host device via the connection interface. Since it can be driven by the circuit power supply, in the power saving mode, the power supply from the external power supply to the main power supply of the display device can be turned off by the power switch, and thus the power consumption of the display device can be eliminated.

The power saving control circuit further comprises a circuit power switch for switching between power supply for driving the power save control circuit from the circuit power supply or the main power supply, and the power save control circuit is connected to the connection from the host device. When the synchronization signal is no longer input via the interface, the circuit power switch is switched to supply power from the circuit power source to the power save control circuit, and when the synchronization signal is input, The circuit power switch is switched to supply power from the main power source to the power save control circuit.
According to this, in the display mode in which power is supplied from the external power supply to the main power supply, it is possible to supply power to the power save control circuit from the main power supply, which is easier to guarantee reliability and stability than the circuit power supply. .

In addition, the video signal, the video signal synchronization signal, the power save transition signal, and / or the display return signal are input from the host device and connected to the host device. A connection interface to which circuit power is supplied, a video display unit that displays video based on the video signal and the synchronization signal input via the connection interface, and a power source from an external power source, the video display unit A main power supply to be supplied to the main power supply, a power switch for turning on / off the power supply to the main power supply, and the circuit power supplied via the connection interface. When the synchronization signal is not input via the power save signal or when the power save transition signal is input, Turn off the power switch to shut off the power supply to the main power supply, stop the power supply to the video display unit, and when the synchronization signal is input or the display return signal is input And a power save control circuit for turning on the power switch to supply power to the main power source and to supply power to the video display unit.
According to this, the power save control circuit which controls switching between the power save mode and the display mode by switching the power switch in accordance with the input state of the synchronization signal, other power save transition signal and / or display return signal. Can be driven by the circuit power supplied from the host device through the connection interface, so in the power save mode, the power supply from the external power supply to the main power supply of the display device can be turned off by the power switch. Accordingly, power consumption of the display device can be eliminated.

The power saving control circuit further comprises a circuit power switch for switching between power supply for driving the power save control circuit from the circuit power supply or the main power supply, and the power save control circuit is connected to the connection from the host device. When the synchronization signal is not input or the power save transition signal is input via the interface, the circuit power switch is switched to supply electricity from the circuit power to the power save control circuit. When the synchronization signal is input or the display return signal is input, the circuit power switch is switched so that electricity is supplied from the main power source to the power save control circuit.
According to this, in the display mode in which power is supplied from the external power supply to the main power supply, it is possible to supply power to the power save control circuit from the main power supply, which is easier to guarantee reliability and stability than the circuit power supply. .

  The display device of the present invention has an advantage that power consumption can be eliminated by turning off the power supply from the external power source to the main power source in the power save mode.

  The best mode for carrying out a display device according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an internal configuration of a liquid crystal display device A which is Embodiment 1 of a display device according to the present invention.
The liquid crystal display device A is connected to a personal computer (hereinafter referred to as PC) 90 as a host device via a connection cable 92 such as a 15-pin D-sub code. One end of the connection cable 92 is connected to the connection interface 90a of the PC 90 such as a 15-pin D-sub connector terminal, and the other end is connected to the connection interface 2 such as a 15-pin D-sub connector terminal of the liquid crystal display device A. , Each connected.
The liquid crystal display device A does not necessarily have to be physically provided separately from the PC 90. For example, the liquid crystal display device A may be formed integrally with the PC 90 and connected to the main board (control unit) of the PC 90 in the PC 90. good.

The PC 90 includes an input unit (not shown) such as a keyboard and a mouse that can be operated by a user to input data, and a control unit (not shown) that includes a CPU, a memory, a hard disk, and the like and can execute a software program. .
Further, the PC 90 is provided with a liquid crystal display device driver for displaying images on the liquid crystal display device A and controlling the liquid crystal display device A in the control unit of the PC 90 so as to be readable by a computer (installation). Is).

The PC 90 transmits a video signal and a synchronization signal (vertical synchronization signal and horizontal synchronization signal) to the liquid crystal display device A via the connection interface 90a and the connection cable 92. The video signal and the synchronization signal are input to the liquid crystal display device A from the connection interface 2 to which the connection cable 92 is connected.
Taking a 15-pin D-sub connector as an example, the video signal is input to the liquid crystal display device A from the first, second, and third pins, the vertical synchronization signal is input from the 14th pin, and the horizontal synchronization signal is input from the 13th pin. The

Further, the PC 90 supplies a so-called 5V power source as a circuit power source for driving an electronic circuit to the liquid crystal display device A through the connection interface 90a and the connection cable 92. The 5 V power is supplied from the connection interface 2 to the liquid crystal display device A.
This 5V power source is provided for the purpose of supplying power to the plug & play device when a plug & play device having no power source is connected to the connection interface 90a of the PC 90. It is not used in display devices with its own power supply (main power supply).
Taking a 15-pin D-sub connector as an example, 5V power is input to the liquid crystal display device A from the 9th pin.

For example, when the user does not operate the input means for a predetermined time, the PC 90 outputs the vertical synchronization signal and / or the horizontal synchronization signal output to the liquid crystal display device A via the connection interface 90a and the connection cable 92. Stop. The liquid crystal display device A shifts to the power save mode when the vertical synchronization signal and / or the horizontal synchronization signal is not input from the PC 90.
Further, the PC 90 re-outputs the vertical synchronization signal and the horizontal synchronization signal when any operation is performed on the input means during the power save mode. The liquid crystal display device A returns from the power save mode to the display mode when the vertical synchronization signal and the horizontal synchronization signal are input from the PC 90.

  The trigger for the liquid crystal display device A to enter the power save mode may be when either the vertical synchronization signal or the horizontal synchronization signal is not input, or both the vertical synchronization signal and the horizontal synchronization signal are input. It may be when it is gone. In other words, the term “when the synchronization signal is no longer input” in the claims of the present application means that either one of the vertical synchronization signal and the horizontal synchronization signal is not input, or both of them are not input. Including.

In the present embodiment, the trigger for liquid crystal display device A to enter the power save mode and return to the display mode is that the input of the vertical synchronization signal and / or the horizontal synchronization signal is stopped or resumed (input). However, the present invention is not limited to this example.
That is, as in claims 3 and 4 of the present application, when a power save transition signal / display return signal other than the synchronization signal is input from the host device to the display device (triggered by being input) You may comprise so that transfer to power save mode / return to display mode may be performed.

Next, the internal configuration of the liquid crystal display device A will be described with reference to FIG.
In the block diagram of FIG. 1, single-line arrows indicate the flow of signals and control, and double-line arrows indicate the flow of power supply.
The liquid crystal display device A includes a connection interface 2, a control circuit 6, a synchronization signal detection circuit 10, a liquid crystal display unit 4 as a video display unit, an external power cord 8, a power switch 14, and a main power source 12. And a circuit power switch 16.

The liquid crystal display unit 4 includes a liquid crystal panel unit and a backlight unit, and is provided so that an image can be displayed.
The control circuit 6 is configured in a microcomputer unit including a CPU, a memory, and the like, and displays the video signal and the synchronization signal on the liquid crystal display unit 4 in order to display the video based on the video signal and the synchronization signal input from the connection interface 2. Signal processing is performed on a signal suitable for display on the liquid crystal display unit 4, and the signal processed signal is transmitted to the liquid crystal display unit 4 to perform display control.

The external power cord 8 is connected to an external power source such as a 100V AC power source and supplies power to the liquid crystal display device A from the external power source.
The main power source 12 is connected to an external power source such as a 100V AC power source via an external power cord 8, and the liquid crystal panel unit and the backlight unit are connected to the external power source for the liquid crystal display unit 4 to display an image. The power source is converted into a power source with a predetermined condition suitable for driving and supplied to the liquid crystal display unit 4, and the power source is converted into a power source with a predetermined condition (DC 5V) suitable for circuit driving to control circuit 6 and synchronization signal detection circuit 10. This is a power supply circuit that can be supplied to (described later).
The power switch 14 is a switch that can switch whether the power from the external power source is input to the main power source 12 (ON) or not (OFF).
The circuit power switch 16 switches whether to supply the power from the circuit power input from the connection interface 2 or the power from the main power supply 12 to the control circuit 6 and the synchronization signal detection circuit 10 (described later). It is a switch that can.

  The synchronization signal detection circuit 10 is provided so as to be able to be driven by the circuit power input from the connection interface 2 and the power from the main power supply 12, and the synchronization signal (vertical synchronization signal and horizontal signal from the PC 90 via the connection interface 2. When one of the synchronization signals is not input, a synchronization signal no signal indicating that the synchronization signal is not input is output to the control circuit 6. On the other hand, the synchronization signal (via the connection interface 2) is output. When both the vertical synchronization signal and the horizontal synchronization signal) are input, the control circuit 6 outputs a synchronization signal presence signal indicating that the synchronization signal is input.

The control circuit 6 performs power source switching control and power source on / off control.
That is, when the synchronization signal absence signal is input from the synchronization signal detection circuit 10, the control circuit 6 switches the circuit power switch 16 to supply power to the synchronization signal detection circuit 10 and the control circuit 6 from the circuit power supply. After the power switch 14 is switched, the power switch 14 is switched so as not to input the power from the external power source to the main power source 12 (turned off) to stop the power supply to the liquid crystal display unit 4 ( By turning on / off the power), the liquid crystal display device A is shifted to the power save mode. Further, when the synchronization signal presence signal is input from the synchronization signal detection circuit 10, the control circuit 6 switches (turns on) the power switch 14 to input the power from the external power source to the main power source 12. After power is supplied to the liquid crystal display unit 4 (power on / off control), the circuit power switch 16 is switched to supply power from the main power 12 to the synchronization signal detection circuit 10 and the control circuit 6 (power switching control). The liquid crystal display device A is shifted to the display mode.

  That is, a power save control circuit configured to control the circuit power switch 16 and the power switch 14 by the synchronization signal detection circuit 10 and the control circuit 6 is configured.

According to the liquid crystal display device A according to the first embodiment, in the power saving mode, the power switch 14 can be turned off to eliminate the input of the external power supply to the main power supply 12, so that the display can be performed as in the related art. Compared with the case where an external power supply is supplied to the power supply circuit of the apparatus, the power saving effect can be greatly enhanced by eliminating the power consumption of the power supply circuit (main power supply 12).
Since the circuit power (5 V power) supplied from the PC 90 via the connection interface 2 is used for driving the power save control circuit, strictly speaking, the power consumption on the PC 90 side slightly increases. In general, the power consumption of a small electronic circuit such as a power save control circuit is very small compared to the power consumed by the power supply circuit of the display device. As a result, the total power consumption of the host device and the display device can be reduced as compared with the conventional case.

  In recent years, CPUs that have a function of shifting to a power saving mode such as a sleep mode and that can reduce power consumption in the power saving mode have become widespread. If the CPU of the control circuit 6 shifts to the power saving mode by the absence of the synchronization signal and the CPU returns from the power saving mode by the synchronization signal present signal from the synchronization signal detection circuit 10, the power of the liquid crystal display device A can be obtained. It is further preferable that the power consumption of the CPU (control circuit 6, and hence the power save control circuit) can be kept low during the save mode, and as a result, the power consumption of the PC 90 can be kept low.

  Further, according to the liquid crystal display device A, the control circuit 6 and the synchronization signal detection circuit 10 are more reliable and more stable than the circuit power supply from the PC 90 in the display mode in which the power supply from the external power supply is supplied to the main power supply 12. Therefore, it is possible to supply power from the main power supply 12 that is easy to guarantee the performance, and it is possible to drive the control circuit 6 and the synchronization signal detection circuit 10 more stably.

  In general, the circuit power supplied from the PC 90 via the connection interface 2 may be unstable in voltage, current, and the like. It is more preferable to rectify the supplied power (electricity).

  In the first embodiment, the main power supply 12 includes a power supply circuit that converts to a predetermined condition for supplying to the liquid crystal display unit 4 and a power supply circuit that converts to a predetermined condition (DC 5 V) suitable for circuit driving. Although both are included, of course, you may comprise both in a separate circuit. Even in that case, according to the liquid crystal display device A of the first embodiment, the input of the external power supply to both power supply circuits can be cut off, and the power consumption can be effectively suppressed.

Next, a liquid crystal display device B which is Embodiment 2 of the display device according to the present invention will be described.
FIG. 2 is a block diagram showing an internal configuration of the liquid crystal display device B. As shown in FIG.
In the liquid crystal display device B of the second embodiment, the same reference numerals are given to the same configurations as those of the liquid crystal display device A of the first embodiment, and the description thereof is omitted.

  The liquid crystal display device B does not include the circuit power switch 16 of the first embodiment, and the power save control circuit including the control circuit 6 and the synchronization signal detection circuit 10 is always a circuit power supply (5 V power supply) input from the connection interface 2. It is driven by. The main power supply 12 does not need to supply power to the control circuit 6 or the synchronization signal detection circuit 10, and therefore does not have a circuit for converting to a predetermined condition (DC 5V) suitable for circuit driving.

  According to the configuration of the liquid crystal display device B of the second embodiment, the circuit power switch 16 can be eliminated and the configuration of the main power source 12 can be simplified as compared with the liquid crystal display device A of the first embodiment. Can be simplified and reduced in cost. Furthermore, since a power supply circuit for converting to a predetermined condition (DC 5V) suitable for circuit drive is provided only on the PC 90 side, power consumption can be suppressed even in the display mode by eliminating useless power supply circuits.

Next, a liquid crystal display device C which is Embodiment 3 of the display device according to the present invention will be described.
FIG. 3 is a block diagram showing an internal configuration of the liquid crystal display device C. As shown in FIG.
In the liquid crystal display device C of the third embodiment, the same reference numerals are given to the same configurations as those of the liquid crystal display device A of the first embodiment, and the description thereof is omitted.

The liquid crystal display device C does not include the circuit power switch 16 of the first embodiment, and the synchronization signal detection circuit 10 is always driven by the circuit power (5 V power) input from the connection interface 2.
On the other hand, the control circuit 6 is supplied with power only from the main power supply 12 and is not supplied from the circuit power input from the connection interface 2.

The control circuit 6 does not control the power switch 14 and does not constitute a power save control circuit.
On the other hand, the synchronization signal detection circuit 10 controls the power switch 14 and constitutes a power save control circuit alone. That is, when the synchronization signal (either one of the vertical synchronization signal and the horizontal synchronization signal) is not input from the PC 90 via the connection interface 2, the synchronization signal detection circuit 10 connects the power switch 14 to the external switch 14. The power supply is switched from the power supply to the main power supply 12 (turned off), and the power supply to the liquid crystal display unit 4 is stopped (power on / off control), so that the liquid crystal display device C shifts to the power save mode. Let Further, when a synchronization signal (both a vertical synchronization signal and a horizontal synchronization signal) is input via the connection interface 2, the synchronization signal detection circuit 10 sets the power switch 14 to supply power from the external power source as a main power source. 12 is switched (turned on) to supply power to the liquid crystal display unit 4 and power is supplied to the liquid crystal display unit 4 (power on / off control) to shift the liquid crystal display device C to the display mode.

  According to the configuration of the liquid crystal display device C of the third embodiment, the configuration can be simplified and the cost can be reduced by eliminating the circuit power switch 16 as compared with the liquid crystal display device A of the first embodiment. Further, since the circuit power supplied from the PC 90 is not supplied to the control circuit 6 during the power save mode, the power consumption of the PC 90 can be reduced.

  When there is a problem that the supply of power to the control circuit 6 is stopped without the control circuit 6 recognizing, the control circuit 6 before the synchronization signal detection circuit 10 turns off the power switch 14. After a sufficient time has elapsed for transmitting the no-synchronization signal to 6 and preparing for the control circuit 6 to be turned off, for example, the synchronization signal detection circuit 10 is connected to the power switch 14. What is necessary is just to comprise so that control which turns off may be performed.

  Although the said Example is liquid crystal display device AC provided with the liquid crystal display part 4 as a video display part, this invention is not limited to this, For example, images, such as a CRT display apparatus provided with a cathode ray tube as a video display part, are shown. It can be applied to any device that displays.

1 is a block diagram of a display device according to Example 1. FIG. 6 is a block diagram of a display device according to Embodiment 2. FIG. FIG. 10 is a block diagram of a display device according to a third embodiment.

Explanation of symbols

A, B, C Liquid crystal display device 2 Connection interface 4 Liquid crystal display unit (video display unit)
6 Control circuit (Power save control circuit. Except Example 3)
8 External power cord 10 Sync signal detection circuit (power save control circuit)
12 Main power supply 14 Power switch 16 Circuit power switch 90 PC (host equipment)

Claims (4)

A connection interface provided so as to be connectable to a host device, to which a video signal and a synchronization signal of the video signal are input from the host device, and a circuit power for driving an electronic circuit is supplied from the host device;
A video display unit for displaying video based on the video signal and the synchronization signal input via the connection interface;
A main power source for supplying power from an external power source to the video display unit;
A power switch for turning on / off the power supply to the main power supply;
Driven by the circuit power supplied via the connection interface, and when the synchronization signal is no longer input from the host device via the connection interface, the power switch is turned off to turn off the power switch. Shut off the power supply to the main power supply, stop the power supply to the video display unit, and when the synchronization signal is input, turn on the power switch to supply power to the main power supply. And a power save control circuit for supplying power to the video display unit. A circuit power switch for switching whether to supply power from the circuit power source or the main power source for driving the power save control circuit,
The power save control circuit causes the circuit power switch to supply power to the power save control circuit from the circuit power supply when the synchronization signal is not input from the host device via the connection interface. 2. The display device according to claim 1, wherein when the synchronization signal is input, the circuit power switch is switched to supply power from the main power source to the power save control circuit. A video signal, a synchronization signal of the video signal, a power save transition signal and / or a display return signal are input from the host device so as to be connectable to the host device, and a circuit for driving an electronic circuit from the host device A connection interface to which power is supplied;
A video display unit for displaying video based on the video signal and the synchronization signal input via the connection interface;
A main power source for supplying power from an external power source to the video display unit;
A power switch for turning on / off the power supply to the main power supply;
Driven by the circuit power supply supplied via the connection interface, when the synchronization signal is no longer input from the host device via the connection interface or when the power save transition signal is input The power switch is turned off to cut off the power supply to the main power supply, the power supply to the video display unit is stopped, and the synchronization signal is input or the display return signal is input And a power save control circuit for turning on the power switch to supply power to the main power supply and supplying power to the video display section. A circuit power switch for switching whether to supply power from the circuit power source or the main power source for driving the power save control circuit,
The power save control circuit, when the synchronization signal is not input from the host device via the connection interface or when the power save transition signal is input, the circuit power switch is connected to the circuit. The power save control circuit is switched to supply electricity to the power save control circuit, and when the synchronization signal is input or the display return signal is input, the circuit power switch is connected to the power save control from the main power supply. 4. The display device according to claim 3, wherein switching is performed so that electricity is supplied to the circuit.

Images