JP4889892B2 - Display device and power saving control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a display device having a power saving function based on an input video signal and a power saving control method thereof.
[0002]
[Prior art]
In order to meet the need for power saving, conventional display devices such as liquid crystal displays and CRTs have been switched to a power saving state depending on the state of the vertical and horizontal sync signals (hereinafter referred to as sync signals) of the input video signal. Some have a power saving function that controls the return to the normal state. As a result, when the power of a terminal such as a connected personal computer is turned off or the connection cable is disconnected, the power is switched to a power saving state, and wasteful power consumption can be suppressed. In general, in order to automatically return to the normal state in the power saving state, it is necessary to detect the change in the state of the synchronization signal. Therefore, the A / D converter of the video signal and the signal after the A / D conversion are displayed on the display unit. The power supply to the signal control circuit or the like for conversion into the output signal is performed in a smaller amount than in the normal state. In order to further save power, it is desirable to stop the power supply to the means for detecting the synchronization signal such as an A / D converter in the power saving state.
[0003]
[Problems to be solved by the invention]
However, if the power supply to the means for detecting the synchronization signal is stopped in the power saving state, there is a problem that when the state of the synchronization signal changes, it cannot automatically return to the normal state.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to automatically switch from a power saving state to a normal state in a display device having a power saving function based on a synchronization signal of an input video signal. An object of the present invention is to provide a display device and a power saving control method thereof that have a return function and further reduce power consumption.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a video input / synchronization signal detection means for inputting a video signal and detecting the synchronization signal, and the display according to the synchronization signal detected by the video input / synchronization signal detection means. In a display device comprising power saving control means for controlling whether the apparatus is in a power saving state or a normal state, power supply to at least the video input / synchronization signal detecting means in the power saving state Comprises a power saving state switching means for switching between a first power saving state to be performed and a second power saving state in which power supply to the video input / synchronization signal detecting means is also stopped . When shifting to the power saving state, the first and second power saving states are switched by the power saving state switching means after maintaining the first power saving state until a predetermined waiting time elapses. And a storage means for storing a record power saving time that is a time from when the power saving state is entered until the return to the normal state, and the record stored in the storage means. A display device comprising waiting time setting means for setting the waiting time based on a power saving time . Thereby, in the power saving state, the power supply to the video input / synchronization signal detecting means is stopped at a constant cycle, so that further power saving can be achieved. Furthermore, if the waiting time is equal to or longer than a predetermined time interval, power is supplied to the video input / synchronization signal detecting means, so that a change in the state of the synchronization signal is detected and automatic return to the normal state is also performed. .
[0005]
Furthermore , when there are many usage forms that return to the normal state within a relatively short time after entering the power saving state, the normal state is maintained until the first power saving state is reached from the second power saving state. This is convenient because there is no waiting for the return to normal.
[0006]
Further, there are provided a selection means for selecting whether or not to switch to the second power saving state, and a time interval for switching the first and second power saving states by the power saving state switching means. A state switching time setting means for setting may be provided.
Moreover, what considered the control applied to the said display apparatus as a power-saving control method of a display apparatus is also considered.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
1 is a block diagram showing a schematic configuration of a main part of the display device X according to the embodiment of the present invention, and FIG. 2 is an A / D converter and a signal in the display device X according to the embodiment of the present invention. FIG. 3 is a diagram showing a transition of power consumption of the control circuit, FIG. 3 is a flowchart showing a processing procedure in the power saving state of the display device X according to the embodiment of the present invention, and FIG. 4 is a display device according to the embodiment of the present invention. FIG. 5 is a flowchart showing a processing procedure before and after entering the power saving state of X. FIG. 5 is a diagram of determining the time for maintaining the first power saving state at the beginning of the transition to the power saving state in the display device X according to the embodiment of the present invention. FIG. 6 is a diagram illustrating a method, FIG. 6 is a diagram illustrating an example of a screen for setting a time interval for switching between the first and second power saving states in the display device X according to the embodiment of the present invention, and FIG. Can be used in the embodiment It is a conceptual diagram including an A / D converter.
[0008]
The display device X according to the embodiment of the present invention is a display device such as a liquid crystal display or a CRT that receives and displays a video signal output from a terminal such as a personal computer.
First, a schematic configuration of the display device X will be described with reference to FIG.
The display device X receives a video signal and converts it into a digital signal, and the vertical / horizontal synchronizing signal (hereinafter simply referred to as a synchronizing signal) of the video signal based on the digital signal from the A / D converter 103. ) (“With input signal” / “without input signal”), a predetermined signal conversion is performed, and signals from the signal control circuit 104 and the signal control circuit 104 that are output to the display unit 102 are input. Display unit 102 that is a liquid crystal panel or the like, a control unit 101 that controls the entire display device X, a storage unit 105 that is a non-volatile RAM or the like that stores data read or written by the control unit 101, an input button, or the like An operation unit 106 is provided. The A / D converter 103 and the signal control circuit 104 constitute the video input / synchronization signal detection means. In order to detect the synchronization signal, power supply to these 103 and 104 is required. The control unit 101 includes an MPU 101a, a main memory 101b, a ROM 101c, a power supply control circuit 101d, and other peripheral devices not shown. The power supply control circuit 101d controls power supply to the A / D converter 103, the signal control circuit 104, the display unit 102, and the like. The MPU 101a executes a predetermined program registered in advance in the ROM 101c. As a result, the state of the synchronization signal is acquired from the signal control circuit 104 connected by the dedicated bus 107, and based on this, the power supply by the power supply control circuit 101d is controlled.
[0009]
Next, referring to FIG. 2, a description will be given of the power saving operation when the input of the synchronization signal is lost and the state continues. The horizontal axis in FIG. 2 is the time axis, and is the power consumption of the A / D converter 103 and the signal control circuit 104 combined.
First, when a connected personal computer or the like is in operation and the synchronization signal is input, the power supply control circuit 101d controls the display unit 102, the A / D converter 103, and the signal control circuit 104. It changes in a normal state (power consumption W1) in which the rated power is supplied and video display on the display unit 102 is performed (time point until P0). When the power of the personal computer is turned off or the connected cable is disconnected, etc., and the synchronization signal is not input (at time P0), the power supply control circuit 101d uses the first power saving state (consumption). Switch to electric power W2). In this first power saving state, the power supply to the A / D converter 103 and the signal control circuit is in an ON state, and a change in the state of the synchronization signal is detected, and the display unit 102 can be supplied in a short time. This is a state in which the minimum necessary electric power W2 for restoring the display is consumed. That is, when the state of the synchronization signal changes, it automatically returns to the normal state.
Here, the A / D converter 103 will be described as an example of the first power saving state with reference to FIG. As shown in FIG. 7, the A / D converter 103 includes a preamplifier unit 201 that performs amplitude adjustment of an analog RGB signal in the video signal, and an A / D that converts the signal after amplitude adjustment into a digital signal. The conversion unit 202 includes a synchronization separation / synchronization signal processing unit 203 that processes a synchronization signal (SYNC signal) in the video signal, and a PLL unit 204 that generates a dot clock from the processed synchronization signal. In the first power saving state, the power supply to the preamplifier unit 201 and the A / D conversion unit 202 is in an OFF state, but the synchronization signal necessary for detecting a change in the state of the synchronization signal is required. The separation / synchronization signal processing unit 203 and the PLL unit 204 are energized. As described above, the first power saving state is a state in which the minimum power necessary for detecting the state change of the synchronization signal is consumed. Conventional so-called power saving is to maintain the first power saving state.
[0010]
In the display device X, after the first power saving state is maintained for a predetermined time T1 (corresponding to the waiting time) from the point of P0, the power supply control circuit 101d performs a second power saving state (consumption). It switches to electric power W3 (= 0) (at the time of P1). In this second power saving state, the power supply to the A / D converter 103 and the signal control circuit 104 is OFF, and power is not consumed, but it cannot be detected even if a change occurs in the synchronization signal. It is in a state where it cannot automatically return to the normal state. In the second power saving state, for example, in the A / D converter 103 shown in FIG. 7, the power supply to the whole is turned off, that is, the state necessary for detecting the state change of the synchronization signal. The power supply to the synchronization separation / synchronization signal processing unit 203 and the PLL unit 204 is also turned off.
Then, after the second power saving state is maintained for a predetermined time T2 from the time point P1, it switches again to the first power saving state (at the time point P2), and during the predetermined time T3, The state is maintained (time until P3). Thereafter, the state change between P1 and P3 is repeated until the synchronization signal is input.
Thereby, it is possible to save more power than when the first power saving state is continued. Even when the use of a connected personal computer or the like is resumed in the second power saving state, it can be automatically restored to the normal state after waiting for a maximum time T2. Here, it is conceivable that the time T2 is set to a time at which the user does not feel uncomfortable while waiting for the reaction of the display device, for example, about 1 to 3 seconds. Also, the time T3 can be set to a very short time because it is sufficient if the synchronization signal can be detected. Times T2 and T3 are preset by the user, and will be described later. Furthermore, the time T1 is provided for a user who frequently uses the system to return to the normal state within a relatively short period of time after entering the power saving state, only for a time of maximum T2 each time. This is because it is inconvenient to wait for the normal state to return. A method for determining the time T1 will also be described later.
[0011]
Next, a processing procedure of power saving control executed by the control unit 101 will be described with reference to FIG. Hereinafter, S301, S302, and the like represent process procedure (step) numbers. In addition, it is assumed that it has already been detected that the state of the synchronization signal is “no input signal” before the start of the processing of FIG.
First, in S301, power supply is controlled by the power supply control circuit 101d so as to make a transition (transition) to the first power saving state.
Next, in S302 and S303, it is determined whether or not the state of the synchronization signal becomes “input signal present” before a predetermined time T1 elapses (time T1 elapse side of S303) (S302). When the state of the synchronization signal becomes “with input signal” by the time T1 (the side with the input signal in S302), the power supply control circuit 101d supplies power in the normal state (the display). After controlling to return to the state in which the video is displayed on the unit 102 (S309), the process ends.
On the other hand, when the state of the synchronization signal remains “no input signal” and the time T1 has elapsed (the time T1 elapsed side in S303), the power supply control circuit 101d makes a transition to the second power saving state. Thus, the power supply control circuit 101d stops the power supply to the A / D converter 103 and the signal control circuit 104 (S304). Then, after this state is maintained until a predetermined time T2 elapses (S305), the power supply is controlled so as to transition again to the first power saving state (S306).
Next, in S307 and S308, it is determined whether or not the state of the synchronization signal is “with input signal” by the time the predetermined time T3 elapses. When the state becomes “with input signal” (the side with the input signal in S307), the power supply control circuit 101d controls the power supply to return to the normal state (S309), and then the process ends. .
On the other hand, when the time T3 has passed with the state of the synchronization signal “no input signal” (time T3 elapse side in S308), the process returns to S304 and the process is repeated.
As a result, the power consumption changes as shown in FIG. 2, and power saving can be achieved rather than continuing the first power saving state.
[0012]
Next, a procedure of processing for determining the predetermined time T1 (hereinafter referred to as first power save time) used in the processing of FIG. 3 will be described with reference to FIG. This process is performed before and after the process of FIG. Assume that it has already been detected that the state of the synchronization signal is “no input signal” at the start of the processing of FIG.
When it is detected that the state of the synchronization signal is “no input signal”, first, in S401, the time during which the first or second power saving state is set, that is, the state of the synchronization signal is determined. The measurement of the time (hereinafter referred to as the power save time) from when “no input signal” once until “input signal exists” starts again.
Next, the past power save time (corresponding to the actual power saving time) already stored in the storage unit 105 is read, and the first power save time T1 is calculated based on this. An example of the calculation method will be described with reference to FIG.
The storage unit 105 has a table in which the power saving times (actual values) Tr_1s to Trns for the past n times and how much the first power saving time T1 is set according to an average value Tr_avr thereof. 501 are stored. The table 501 is registered in advance. The MPU 101A of the control unit 101 obtains an average value Tr_avr of the power save times Tr1s to Trns, reads the time corresponding to the average value Tr_avr from the table 501, and sets it as the first power save time T1.
[0013]
Here, data set in the table 501 will be described.
In general, the average Tr_avr of the power saving time is long, which means that the user leaves the seat for a long time with the personal computer or the like turned on, or even if the personal computer or the like is turned off. It is considered that there are many usage situations where the power is not turned off. For such users, since it is considered that there is little use situation in which the normal state is restored in a short time after entering the power saving state (power save state), If the first power saving time T1 provided in consideration is shortened, power can be saved efficiently.
On the other hand, the fact that the average Tr_avr of the power saving time is short means that the user often uses the power saving normal state (power saving state) to return to the normal normal state in a relatively short time. It is done. For such a user, the return to the normal state is quicker when the first power save time T1 is increased, that is, when the user does not immediately shift to the second power saving state. So convenient.
Therefore, data is set in the table 501 in advance such that the first power save time T1 is shorter as the average Tr_avr of the power save time is longer.
[0014]
As described above, when the first power save time T1 is calculated in S402, the process proceeds to S403 and the above-described process shown in FIG. 3 is executed.
When the process of S403 (the process of FIG. 3) is finished, the measurement of the power save time started in S401 is finished (S404), and after the power save time is stored in the storage unit 105, the process is finished. . The power saving time is overwritten in order from the oldest, and the latest n are saved.
[0015]
Next, a method for setting times T2 and T3 for switching the first and second power saving states will be described with reference to FIG.
When a predetermined operation is performed from the operation unit 106, a screen as shown in FIG. 6A is displayed on the display unit 102 by the MPU 101 a of the control unit 101. Further, the power saving priority level 601 can be selected from four levels 1 to 4 by a predetermined operation of the operation unit 106. When the power saving priority level 601 is selected, a table 602 (FIG. 6B) registered in advance in the storage unit 105 is referred to, and a combination of times corresponding to the selected power saving priority level 601 ( T2_1, T3_1) to (T2_4, T3_4) are read out and set as time intervals T2 and T3 for switching between the second and first power saving states (this processing is performed by the state switching time setting means). Fall under). Here, in the time combinations (T2_1, T3_1) to (T2_4, T3_4), the time T2 during which the second power saving state is maintained as the value of the power saving priority level 601 is larger (the priority is higher). Is set such that the time T3 for maintaining the first power saving state is short.
As a result, it is possible to switch the operation according to the user's preference whether to prioritize power saving or convenience. That is, for a user who wants to prioritize power saving, the power saving can be further achieved by lengthening the time T2 for the second power saving state. On the other hand, for users who prioritize convenience over power saving, shortening the time T2 during which the second power saving state is set can shorten the normal state where the normal state can be quickly restored (the first power saving state). Power state) can be kept long.
Further, for example, when “1” is selected as the power saving priority level 601, the transition to the second power saving state is prevented, that is, the power saving priority level 601 is set to other than “1”. It may be possible to select whether or not to switch to the second power saving state depending on whether or not it is set to “1”. In this case, when the power saving priority level 601 is “1”, it may be configured to always return to S302 regardless of the elapse of time T1 in S303 of FIG.
[0016]
【Effect of the invention】
As described above, according to the present invention, in a display device having a power saving function based on a synchronization signal of an input video signal, it has a function of automatically returning from a power saving state to a normal state and further saving power. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of a main part of a display device X according to an embodiment of the present invention.
FIG. 2 is a diagram showing a transition of power consumption of an A / D converter and a signal control circuit in the display device X according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a processing procedure in a power saving state of display device X according to the embodiment of the present invention.
FIG. 4 is a flowchart showing a processing procedure before and after entering a power saving state of display device X according to the embodiment of the present invention.
FIG. 5 is a diagram for explaining a method for determining a time for maintaining the first power saving state at the beginning of transition to the power saving state in the display device X according to the embodiment of the present invention.
FIG. 6 is a diagram showing an example of a screen for setting a time interval for switching between the first and second power saving states in the display device X according to the embodiment of the present invention.
FIG. 7 is a conceptual diagram including an A / D converter that can be used in an embodiment of the present invention.
[Explanation of symbols]
101 ... Control unit 101a ... MPU
101b ... Main memory 101c ... ROM
101d ... Power supply control circuit 102 ... Display unit 103 ... A / D converter 104 ... Signal control circuit 105 ... Storage unit 106 ... Operation unit 107 ... Dedicated bus W1 ... Power consumption W2 in normal state ... In the first power saving state Power consumption W3 ... Power consumption T1 in the second power saving state ... First power save time (time in the first power saving state)
T2 ... second power saving state time T3 ... first power saving state time P0 ... time point P1 when transitioning from the normal state to the first power saving state P1 ... second power saving state from the first power saving state Time point P2 when transitioning to Steps 501, 602 ... Table 601 ... Power saving priority level when transitioning from the second power saving state to the first power saving state

Claims (4)

A video input / synchronization signal detecting means for inputting a video signal and detecting the synchronization signal; and a state in which the display device is put into a power saving state or a normal state according to the synchronization signal detected by the video input / synchronization signal detecting means; In a display device comprising power saving control means for controlling whether or not to perform, when the power saving state is set, at least a first power saving state for supplying power to the video input / synchronization signal detecting means, and In addition to the power saving state switching means for switching the second power saving state in which the power supply to the video input / synchronization signal detecting means is also stopped at a predetermined time interval, and when shifting to the power saving state, After the first power saving state is maintained until a predetermined waiting time elapses, the first power saving state switching control by the power saving state switching means is started. Further, a storage means for storing an actual power saving time that is a time from when the power saving state is entered until the return to the normal state, and the waiting based on the actual power saving time stored in the storage means. A display device comprising waiting time setting means for setting time . The display device according to claim 1, further comprising selection means for selecting whether or not to switch to the second power saving state. The display device according to claim 1 or 2 comprising comprises a state switching time setting means for setting a time interval for switching the first and second power-saving state by the power-saving state switching means. In a power saving control method for a display device for controlling whether to enter a power saving state or a normal state according to the synchronizing signal detected by a video input / synchronizing signal detecting means for inputting a video signal and detecting the synchronizing signal In the power saving state, at least a first power saving state for supplying power to the video input / synchronization signal detecting means and a second power supply for stopping the video input / synchronizing signal detecting means. saving state and switching at predetermined time intervals Rutotomoni, when a transition to the power saving state of, after maintaining the first power saving state until a predetermined waiting time has elapsed, the first And the second power saving state switching control is started, and the actual power saving time, which is the time from when the power saving state is entered until it returns to the normal state, is stored, and the stored actual power saving time is stored. In Power saving control method of the display device and sets the wait time Zui.

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