JP2001337309A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the power reduction in the non-operation state of a liquid crystal display device and to reduce the power at the time of the non-operation of the device by allowing the user side to set arbitrarily the time of the non- operation state regardless of the presence or absence of a synchronizing signal and a video signal from a PC. SOLUTION: This display device is made to have a constitution in which on the liquid crystal display device 1 side, a non-operation time is judged by detecting a time when pixel information is not changed with a pixel converting circuit 8 and a CPU 10 and control for lowering a back light 5 or the like is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art The market size of liquid crystal displays has been increasing dramatically. This is because, compared with the conventional CRT display, a small space and low power, which are features of the display liquid crystal display device, have been accepted.

[0003] In recent years, further power saving has been demanded, and the required minimum power consumption has been demanded.

In general, in the display field, in a non-operation state (for example, when no keyboard input or mouse operation is performed on the PC for a certain period of time), the display side detects the presence or absence of horizontal synchronization and vertical synchronization signals from the PC side. In order to cut off the power supply mainly to the parts that consume power (such as the backlight) (standard: DPMS (Display Power Management Singnal)
s)).

As described above, conventionally, as a means for detecting a no-operation state, the presence or absence of a synchronization signal from a PC is mainly detected and determined on the display side (for example, Japanese Patent Laid-Open No.
-85091, JP-A-10-161600, and JP-A-10-319912).

Further, there is a means for detecting the presence or absence of a video signal and shifting to a power saving mode when a screen is blacked out. However, as a problem, it was necessary to set a screen saver and dedicated software on the PC side.

[0007]

In the method for detecting the presence / absence of a synchronization signal from a PC as in the above prior art, P
The state shifts to the standby power mode state only during the time (DPMS) determined on the C side, and the user cannot arbitrarily set the time to the standby power mode (for example, within the above set time). To measure low power in a shorter time without operation,
It is necessary to detect the no-operation state on the display side itself.

The present invention is to improve the power reduction in the non-operation state in the liquid crystal display device as described above, and arbitrarily sets the time of the non-operation state regardless of the presence or absence of a synchronization signal from a PC. Provide reduced power during no operation.

[0009]

In order to solve the above-mentioned problems, the liquid crystal display device of the present invention detects a non-change time of pixel information on the display device side to determine no operation and lowers the backlight. This provides means for controlling and reducing power consumption.

With this configuration, it is possible to detect the time of no operation on the display side without detecting the presence / absence of the synchronization signal and the video signal of the PC, so that the user can arbitrarily transition to the power saving mode. It can be set, and a transition to low power (standby power mode) can be realized in a shorter time, and power saving can be achieved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a panel module, a pixel conversion circuit, a synchronization processing circuit,
A liquid crystal display device comprising a backlight, a CPU and a power supply circuit for driving them, arbitrarily setting a non-operation state, shifting to a standby mode to reduce power, and determined by a PC. It is possible to shift to the standby mode independently of the time of the no-operation state to promote power reduction.

[0012] The invention described in claim 2 of the present invention provides:
2. The liquid crystal display device according to claim 1, wherein the non-operation state is determined by detecting presence or absence of a change in pixel information in a pixel conversion element. It can be set and shifted to standby power.

An embodiment of the present invention described in claim 2 of the present invention will be described below with reference to FIG.

(Embodiment 1) FIG. 1 is a diagram showing an embodiment of the present invention. As shown in FIG. 1, a liquid crystal display device 1 of this embodiment includes a commercial power connector 2, a power circuit 3, a power supply control switch 4 for each circuit, an inverter circuit 5, a synchronization processing circuit 6, a panel module 7, a pixel conversion circuit. 8, OSD circuit 9, CPU 10, input connector 11,
Key input SW12, power supply control SW1 for pixel conversion circuit
3

In general, the liquid crystal display device 7 processes the video signal and the synchronization signal from the input connector 11 by the pixel conversion circuit 8 and the synchronization processing circuit 6, respectively, and transmits the processed signal to the panel module 7 for display. The power supply is
AC power is supplied to the commercial power connector 2 and AC-DC converted by the power circuit. The converted power is converted into a voltage required for each circuit block and supplied to each circuit via SW4. However, it is supplied to the CPU 10 without going through the SW4.

In a normal state (screen display), SW4 is
The state becomes N and each circuit operates. In a generally known power save (power saving mode), a transmitting PC controls a synchronization signal input from the signal connector 11 (cuts off vertical synchronization and horizontal synchronization), and sends the control signal to the CPU via a synchronization processing circuit 6.
Means for controlling SW4 and SW13 by detecting at 10 is provided.

In the present invention, instead of detecting a synchronization signal from a PC, the CPU 10 monitors pixel information processed by the pixel conversion circuit 8 and counts a time during which the pixel information does not change. When the image does not change for a certain period of time,
SW4 is cut off, or the backlight (brightness) is reduced by an inverter circuit which is a main part of power consumption (CPU
10) to save power. The setting of the fixed time is processed by the OSD 10 and the pixel conversion circuit
8. In the image displayed through the panel module 7, the user can search with the key SW12 and set arbitrarily. In this way, the display device 7 can arbitrarily set the transition time to the standby power mode.

[0018]

As described above, according to the liquid crystal display device of the present invention, the pixel information by the pixel conversion circuit is stored in the CPU.
When the pixel information does not change for a certain period of time (user set time), the power supply is cut off or the backlight is turned down, so that a no-operation transmission signal (a synchronization signal Irrespective of the presence / absence), the user can arbitrarily set the time to the standby power mode on the liquid crystal display device, and it is possible to further save power.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a liquid crystal display device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Commercial power supply connector 3 Power supply circuit 4 Each circuit power supply control SW 5 Inverter circuit (backlight) 6 Synchronization processing circuit 7 Panel module 8 Pixel conversion circuit 9 OSD 10 CPU 11 Connector for input signal 12 Key SW 13 Pixel conversion Power control SW for circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) G09G 3/36 G06F 1/00 334G F term (reference) 2H093 NC01 NC09 NC11 NC44 NC50 NC52 ND39 5B011 EA02 EB09 LL14 MA03 5C006 AA22 AB03 AC02 AF53 AF69 BF15 BF27 BF44 EA01 FA47 5C080 AA10 BB05 CC03 DD26 EE32 FF09 JJ02 KK02

Claims (2)

[Claims] 1. A panel module, a pixel conversion circuit,
A liquid crystal display comprising a synchronous processing circuit, a backlight, a CPU, and a power supply circuit for driving them, and arbitrarily setting a no-operation state and shifting to a standby mode to reduce power. apparatus. 2. The liquid crystal display device according to claim 1, wherein the non-operation state is determined by detecting whether or not the pixel information has changed in the pixel conversion element.