JPH0659653A - Image display device - Google Patents

Abstract

PURPOSE:To save electric power consumption by cutting off an electric power source of a part of circuits inside an image display device without making a part of blink display in the extinguished state. CONSTITUTION:An image formed in an image memory 2 by an image forming circuit 1 is, after it is once accumulated in a display memory 4, displayed by display device 5. A microprocessor 6 cuts off an electric power source of the image forming circuit 1 to reduce electric power consumption after once changing a blinking part of a blink display in the state of constant display at the time when the content of a display data is not changed. During that time, the display device 5 displays a display data brought into the state to constantly display which is accumulated inside of the display memory 4. The microprocessor 6 connect the electric power source of the image forming circuit 1 in the case when the content of the display data is required to change, and thereafter, it returns the display data in the state to constantly display which is rewritten before the electric power source is cut off to the blink display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for displaying an image.

[0002]

2. Description of the Related Art Conventionally, in a battery-powered portable word processor, portable personal computer, or the like, there is a strong demand from the market for long-term operation and reduction in size and weight of the device. For this reason, it is important to reduce the power consumption of the device to reduce the size of the battery to reduce the size and weight of the device as a whole, and to operate for a longer period of time with batteries of the same size. ing.

For the purpose of reducing the power consumption of the apparatus, an electronic device of a circuit portion having an unused function is put into a low power consumption state called a standby mode or a sleep mode, and the power supply of the unused circuit portion is cut off and operated. Methods have been developed to stop or reduce the clock frequency. In addition, it has a function to constantly monitor the keyboard, switches, etc., and when the operator does not operate for a certain period of time, puts the circuit part that does not interfere with the operation into a low power consumption state or a power off state, It is also stopped or lowered.

On the other hand, there is an image display circuit as one of the circuit parts which consumes a large amount of power in the apparatus. An ordinary device is required to display an image at high speed, and therefore it is necessary to process image data at high speed. Therefore, the circuit portion that performs image processing usually operates with a clock having a very high frequency in many cases. Since the power consumption of the circuit is often proportional to the operation clock, the image data processing unit operating at high speed usually consumes a large amount of power. Therefore, it is necessary to apply the above-mentioned measures for reducing power consumption to the image display circuit.

FIG. 2 is a diagram showing an example of the configuration of a conventional image display circuit, in which circuits not directly related to the description are omitted.

The image generation circuit 1 includes a microprocessor 6
In accordance with the image generation instruction signal 9 from, the data of the image to be displayed is generated on the image memory 2, and the data is displayed.
Send to. The generated data may be character data such as alphabets, numbers, kana, kanji, or graphic data such as figures. In order to generate data at high speed, character data development hardware and drawing hardware are often installed in the image generation circuit.

As the image generation circuit 1, for example, there is a μPD7220 manufactured by NEC, which is called a graphic display controller (GDC). μPD
The 7220 has functions such as drawing a circle, a straight line, and a rectangle on the image memory at high speed, expanding character data at high speed, and setting a cursor shape by a command from the microprocessor. For an example of the functions of this LSI and how to use it in a personal computer, see 1983.
“ΜPD7220 User's Manual (issued by NEC Corporation)” issued on October 20, 1998, “New Edition PC9800 Series Technical Data Book (issued by ASCII Corporation)” issued on April 1, 1990, 1988 2
For details, please refer to "98 Hardening Book II (published by Technical Review Co., Ltd.)" issued on 25th of March.

The image memory 2 is a memory for holding image data corresponding to each pixel of the display screen. In addition to a normal RAM, a RAM for image data (VRA) capable of high-speed processing.
M) may also be used.

The image generation circuit 1 reads the generated data from the image memory 2 and sends it to the display control circuit 3. The display control circuit 3 sends the display data to the display device 5 at regular intervals. The display device 5 may be a CRT display or, in recent years, an L
CD panels are often used.

In the usual case, the display device 5 does not have a function of holding the display data for a long time by itself, so if the data is not sent to the display device 5 within a certain time, the display screen disappears or is disturbed. In order to avoid this, the display control circuit 3
Generates various control signals such as CRT display, LCD panel operating clock, and sync signal,
These control signals and the display data received from the image generation circuit 1 are constantly transferred to the display device 5 at a constant cycle.

On the other hand, in the image display device, there is a case where display data, which is generally called blinking, is displayed in which the display data blinks at a constant cycle. Blinking makes it easier for the operator to recognize the cursor that indicates the position on the display screen of the characters to be input from the keyboard, indicates that the device is waiting to input data from the keyboard, or emphasizes the displayed contents. It is widely used in word processors and personal computers for the purpose of

Blinking is usually performed by the image generating circuit 1 as in the case of creating normal display data. When the microprocessor 6 designates blinking, the image generation circuit 1 repeatedly displays the designated display contents such as a display state and a non-display state at a certain cycle independently of the operation of the microprocessor 6. Blink. The blinking is performed until the microprocessor 6 next changes the designation. In the personal computer PC9801 series using the above-mentioned LSI and μPD7220, blinking of the designated character or cursor is automatically performed by the LSI according to the instruction of the microprocessor.

Information about which part of the display data is set to the blink state is stored in the attribute memory 8 controlled by the image generation circuit 1. The image generation circuit 1 repeatedly rewrites the contents of the image memory 2 according to the contents of the attribute memory 8 in a display state and a non-display state at a constant cycle. The attribute memory 8 may hold information such as display color and brightness in addition to the information regarding blinks.

[0014]

It is considered that the above-mentioned measure for reducing power consumption is applied to such a conventional image display circuit. While the display data is being updated, the information that should be displayed according to the operating state of the device is not displayed and the internal state of the device is completely unknown to the operator. Therefore, it is possible to stop any of the circuit blocks in FIG. It is possible. Therefore, the power consumption should be reduced when the display data is not updated and the display screen is stopped.

However, in the conventional image display circuit,
Even when the display data is not updated, the image data will not be transferred to the display device 5 even if any of the circuit blocks in FIG. The screen will disappear. For this reason, there is a disadvantage that it is inconvenient when the operator is looking at the screen on the display device without updating the display data, and after the display of the image is stopped, the operator is Since it is not possible to determine whether or not is operating, there is a risk of mistakenly operating the power switch or determining that the device has failed.

Further, these circuits restart the display again when the display contents are updated by the keyboard operation, but in the state where the image is not displayed on the display device, the device is stopped in what state it is at present. There is a contradiction that the operator cannot determine whether the operation is being performed and does not know what operation should be performed.

Therefore, for these reasons, there is a problem in that the function of stopping the operation of the image display circuit when the display data is not updated cannot be applied to the apparatus.

When the circuit is in the low power consumption state,
The blink display part may also disappear, and it is necessary to take measures against the blink display.

[0019]

According to the present invention, image generation means for generating image data to be displayed on a display device, means for accumulating image data generated by the image generation means, and the image A means for displaying the image data accumulated in the accumulating means on the display device and consumption by stopping or lowering some or all of the functions of the image generating means when the image data does not change for a certain period of time. Means for reducing power, and means for displaying image data accumulated in the image accumulating means on a display device while the function of the image generating means is stopped or lowered,
When it is necessary to change the image data, it includes means for returning the stopped or lowered state of the function to a normal state, and further, after storing the data indicating the situation in the blinking display in the displayed image, the blinking display in the image. And a means for reducing the power consumption by changing some of the functions of the image generating means and the means for accumulating the image data to a stopped or lowered state. , After returning the function of the image generating means to a normal operation state when it is necessary to change the image data,
According to the saved data of the blinking status,
An image display device including means for returning the image data from the constantly displayed state to the blinking state is obtained.

[0020]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. Here, for ease of description, first, a case will be described in which the power supply of only the image generation circuit 1 is cut off and the power supplies of the image memory 2 and the attribute memory 8 are always connected. The case where the image memory 2 and the attribute memory 8 are turned off in addition to the image generation circuit 1 will be described later.

The device of this embodiment performs the following operations.

The image generation circuit 1 reads the generated data from the image memory 2 and sends it to the display control circuit 3. The display control circuit 3 temporarily stores this in the display memory 4, then reads the data and sends it to the display device 5. The display control circuit 3 sends the display data accumulated in the display memory 4 to the display device 5 at regular intervals. As the display device 5, a CRT display, an LCD panel or the like has been widely used in recent years.

In the normal case, the display device 5 does not have a function of holding the display data by itself for a long time. Therefore, if the data is not sent to the display device 5 within a certain time, the display screen disappears or is disturbed. In order to avoid this, the display control circuit 3
Generates various control signals such as CRT display and LCD panel operation clocks and synchronization signals,
These control signals and the display data received from the image generation circuit 1 are constantly transferred to the display device 5 at a constant cycle.

When the display data is not updated, the microprocessor 6 instructs the power supply control circuit 7 to turn off the power supply of the image generation circuit 1, the image memory 2 and the attribute memory 8 by the power supply control signal 11. The power supply control circuit 7 turns off the power supply of the image generation circuit 1, the image memory 2, and the attribute memory 8 according to the instruction.

While the power is off, the display data is not sent from the image generation circuit 1 to the display control circuit 3,
The display control circuit 3 sends the display data accumulated in the display memory 4 to the display device 5 at regular intervals. Therefore, the display device 5 continues to display the display data stored in the display memory 4.

When the keyboard input data signal 12 from the keyboard is input in the state where the power is off and the display data needs to be updated as a result, the microprocessor causes the power control circuit 7 to generate the image generation circuit 1 and the image memory. 2 and the attribute memory 8 are instructed to be connected to the power source, and then the image generation instruction signal 9 is sent to the image generation circuit 1 to generate new display data.

Even when no input is made from the keyboard, the display data may be updated at regular intervals for the purpose of displaying the current time on a part of the display screen. Similarly, the power supply is connected.

Next, the operation of blink display will be described. (Operation 1) First, before the microprocessor 6 attempts to turn off the power of the image generation circuit 1 as described above,
It is checked whether or not there is a blinking display portion of the display data stored in the image memory 2. In the present embodiment, since the blink information is stored in the attribute memory 8 managed by the image generation circuit 1, the microprocessor 6 reads the blink information inside the attribute memory 8 via the image generation circuit 1 and blinks it. Find the part. (Operation 2) When the display data includes blink information, the microprocessor 6 saves the information in the storage memory 9. The storage memory 9 may be of any type as long as it is writable and readable, and may be a part of RAM in a memory space for storing programs and data in a normal computer, or may only store blink information. A dedicated memory for holding may be prepared. (Operation 3) The microprocessor 6 changes the blink information of the display data of the attribute memory 8 from the blinking display state to the normal display state. The change may be performed by an image generation signal from the microprocessor to the image generation circuit 1 or may be performed by writing an independent command. (Operation 4) The microprocessor 6 waits until all the display data (blink portion data) changed in (Operation 3) is sent to the display control circuit 3. As a result, the screen remains displayed with the blinking portion. (Operation 5) Since the state in which the blink portion is constantly displayed is realized by (Operation 4), the microprocessor 6
For the power supply control circuit 7, turn off the power of the image generation circuit 1.
It is instructed by the power supply control signal 11.

By the above (Operation 1) to (Operation 5),
It is possible to reduce power consumption while the blink part remains in the display state. (Operation 6) When it is necessary to update the display data due to the operation of the keyboard by the operator, the microprocessor 6 causes the power supply control circuit 7 to connect the power supply of the image generation circuit 1 with the power supply control signal 11. Give instructions. (Operation 7) The microprocessor 6 reads the blink information saved in the storage memory 9, and accordingly returns the display of the portion of the attribute data in the attribute memory 8 to be blinked to the designation of the blink state. . By this operation, the display data returns to the state before (operation 1).

Next, the case where the image memory 2 and the attribute memory 8 are powered off in addition to the image generation circuit 1 will be described. In this case, since the display data inside the image memory 2 and the display attribute data inside the attribute memory 8 disappear when the power is turned off, these data need to be stored in another memory. Therefore, in (Operation 2), only the blink information in the display data was saved in the storage memory 9, but in addition to this, all the display data and other display attribute information are also saved, and these are saved in (Operation 7). The point that all the data is read out and restored is different from the case where only the power source of the image generation circuit 1 is cut off.

Further, in the present embodiment, the microprocessor 6 gives instructions from (operation 1) to (operation 7).
The present invention is not limited to this, and dedicated hardware or the like may be added.

Further, although the image memory 2, the display memory 4, the attribute memory 8 and the storage memory 9 are separate for simplification of description, they are physically the same memory due to the configuration of the apparatus. Or, of course, it may be configured by a logic element other than the memory.

Further, in the present embodiment, the power consumption is reduced by turning off the power supply of the image generating circuit 1, but the present invention is not limited to this, and the electronic device in the circuit is put into a low power consumption state or the operation clock is reduced. Even if the power consumption is reduced by using the method of stopping or lowering the frequency, it is obviously one of the embodiments of this patent.

[0035]

As described above, according to the present invention, it is possible to reduce the power consumption of the image display device without causing the blink display portion to disappear.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a circuit of the present invention.

FIG. 2 is a diagram showing a configuration example of a conventional image display circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 image generation circuit 2 image memory 3 display control circuit 4, 5 display device 6 microprocessor 7 power supply control circuit 8 attribute memory 9 image generation instruction signal 11 power supply control signal 12 keyboard input data signal

Claims (1)

[Claims] 1. An image generating means for generating image data to be displayed on a display device, a means for accumulating the image data generated by the means for generating an image, and image data accumulated in the image accumulating means. Is displayed on the display device, and when the image data does not change for a certain period of time,
Means for reducing power consumption by stopping or lowering some or all of the functions of the image generating means, and an image accumulated in the image accumulating means while the functions of the image generating means are stopped or reduced. A means for displaying the data on the display device, a means for returning the stopped state or the lowered state of the function to a normal state when it is necessary to change the image data, and a data indicating the state of blinking display in the display image are stored. After that, the portion of the image that is blinking is changed from blinking to a state in which it is constantly displayed, and then some or all of the functions of the image generating means and the means for accumulating image data are stopped or lowered. A means for reducing the power consumption and a function of the image generating means when the image data needs to be changed are returned to a normal operation state and then stored. An image display device having means for returning the image data from a state in which the image data is constantly displayed to a state in which the image data is blinking, according to the data of the state of the blinking display.