JPH09101762A - Portable electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically set the contrast of a display screen to an optimum value by automatically deciding a display mode and controlling a contrast voltage value matching the display mode. SOLUTION: This equipment has a display control means 11 which generates a display timing signal for a 1st or 2nd display mode selectively. Further, the equipment is equipped with a power source control means 21 which supplies electric power to a 1st display device 25 according to a voltage determined by the contents of a register and a mode specifying means 5 which previously holds the respective modes and information showing respective voltage values for displaying information on the 1st display device 25 with an adequate contrast so that they correspond to each other, and informing a display control means 11 of a specified mode once receiving mode specification from a user and also reads information showing the voltage value made to correspond to the specified mode and then writes it in the register. Then the contrast voltage value matching the display mode is controlled according to the display mode that the user selects to obtain the optimum contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a flat panel
The present invention relates to a portable electronic device such as a laptop computer having an integrated display, which is particularly connectable to an external CRT device and capable of displaying.

[0002]

2. Description of the Related Art In a conventional portable electronic device, in addition to displaying on an integrated LCD device, a connection terminal for an external CRT is provided, and an external CRT is connected to this terminal by a connection cable or the like.
There was one that could be connected to the device and display. Such a portable electronic device is generally provided with an LCD display mode, a CRT display mode, and a simultaneous display mode, and is configured so that the user can easily select with an input means such as a keyboard. The display controller, which is built in the portable electronic device and controls display, supplies the display timing for the LCD to the LCD device in the LCD display mode, but in the simultaneous display mode, the CRT device and the LCD device. Since it is necessary to make the display period of one screen the same, the LCD is usually aligned with the display period for CRT
Supply a display timing signal to the device. Therefore, LCD
When the display mode is switched to the simultaneous display mode, the display period of one screen is delayed, the contrast of the LCD device is lowered, and the screen becomes difficult to see.

FIG. 3 is a diagram showing changes in contrast in the LCD display mode and the simultaneous display mode.
As described above, for example, when the user changes from the LCD display mode to the simultaneous display mode, the display controller sends the display timing signal to the LCD device and the external CRT device. Then, since the display timing signal is output in synchronization with the display timing of one screen of the external CRT device, the contrast change graph is changed from the graph A to the graph B and becomes the point (4-5), so that the contrast is lowered. Resulting in.

Therefore, in order for the LCD device to display the optimum contrast, the user changes the resistance value such as a variable resistor with a memory attached to the screen or the side face of the LCD device,
The contrast voltage value had to be changed from point (4-3) to point (4-4).

Therefore, the user manually operates a rotary switch or the like for changing the resistance value of a variable resistor with a memory provided on the screen or side surface of the LCD device in order to compensate for the decrease in contrast, while operating the contrast. The voltage value was changed to adjust the contrast so that it was the easiest to see.

[0006]

As described above, the conventional LC is used.
In a portable electronic device having a D display mode and a simultaneous display mode, when changing from the LCD display mode to the simultaneous display mode and when changing from the simultaneous display mode to the LCD display mode, the user has to rotate the switch etc. Therefore, it is necessary to change the contrast voltage to adjust the contrast to the one that is most easy to see.

The present invention solves the problems in the prior art as described above. Even if the user changes the display mode involving the display timing, the user does not have to manually operate the display mode.
It is an object of the present invention to provide a portable electronic device capable of automatically setting the contrast of a display screen optimally.

[0008]

In order to solve the above-mentioned problems, a first display device and a connector for connecting to an external CRT device are provided, and a display is provided only on the first display device.
A portable electronic device capable of switching between a display mode and a second display mode for simultaneously displaying the first display device and an external CRT device connected by a connector according to a mode designation from a user. Control means for selectively generating a display timing signal for display and a display timing signal for the second display mode, and a power supply control for supplying power to the first display device based on the voltage determined by the contents of the register. Means and each mode and information indicating each voltage value for displaying the first display device with a suitable contrast are held in advance in correspondence with each other, and when the mode is designated by the user, the designated mode is held. Is notified to the display control means, and the information indicating the voltage value associated with the designated mode is read out and written in the register. Characterized by comprising a chromatography de specifying means.

In such a portable electronic device, the display mode selected by the user is automatically discriminated, and the contrast voltage value suitable for the display mode is controlled to allow the user to compensate for the decrease in contrast. Optimal contrast can be obtained without manually operating, for example, a rotary switch or the like attached to the front surface or the side surface of the device.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. Figure 1 shows an external CR
It is a system block diagram which shows the electric constitution of the portable electronic device (it is hereafter called PC) which connected T. In addition, what is surrounded by a dotted line is an integrated portable electronic device.

FIG. 2 is a diagram showing a PWM register for storing a contrast setting command and a generated PWM signal. In FIG. 1, the CPU 1 controls the entire PC 100. The RAM 3 stores programs used by the personal computer. The basic input / output system (BIOS) 5 is
A group of programs that contains the basic operations of a computer,
Controls I / O hardware. The power board 7 supplies power to the system. Gate array (GA) 9
Is an interface for transmitting and receiving data between the BIOS 5 and the power supply board 7. The display controller 11 controls display. Keyboard 13
It is a key input by the user. The hot key 15 is arranged on the keyboard 13, and when the key is pressed, a sequential display mode switching request is issued to the BIO.
Notify S5. Keyboard controller (KBC) 1
Reference numeral 7 controls an interface for data transmission / reception between the BIOS 5 and the keyboard 13. The complementary metal oxide semiconductor (C-MOS) 19 holds the hardware setup state.

A power supply microcomputer 21 is provided in the power supply board 7. As shown in FIG. 2, the power supply microcomputer 21 includes a register group including a PWM register 70. The PWM register 70 includes the BIOS 5
The contrast setting data 60a or 60b transmitted from the above through the GA 9 is set. Based on the setting, the power supply microcomputer 21 sets the pulse amplitude modulation signal (P
WM signal) 55a or 55b is generated. The filter circuit 23 converts the analog signal of the contrast voltage value based on the pulse width of the PWM signal 55a or 55b and transmits the analog signal. The LCD device 25 includes the filter circuit 2
The voltage value for display is determined based on the analog signal from the display unit 3, and the display is performed based on the display timing signal that supplies the display timing from the display controller 11.

The external CRT device 33 is the PC 1
00 is connected to the external CRT connection terminal 34 using, for example, a connection cable. Then, the external CRT device 33 is displayed based on the display signal supplied with the display timing from the display controller 11. The PC 100 has a function of selecting a display device for displaying data by pressing the hot key 15.

Next, the operation of the configuration of this embodiment will be described. The PC 100 is connected to the external CRT device 33 via a connection terminal 34. In this embodiment, an LCD display mode for displaying on the LCD device 25,
It has a CRT display mode for displaying on the external CRT device 33 and a simultaneous display mode for displaying on both the LCD device 25 and the external CRT device 33. By successively pressing the hot key 15, the LCD display mode, the CRT are displayed. The display mode and the simultaneous display mode can be selected in this order.

First, the case of changing from the simultaneous display mode to the LCD display mode will be described. When operating in the simultaneous display mode, the user presses the hot key 15
When pressed down, the KBC 17 detects that the hot key 15 is pressed, and notifies the BIOS 5 of a signal indicating a display mode switching request. BIOS 5
Receiving this signal, recognizes that there is a change request from the simultaneous display mode to the LCD display mode which is the next mode.

Then, the BIOS 5 first operates the LCD device 25 in the LCD display mode.
The display controller 11 which supplies the display timing signal to the display device is instructed to transmit the display signal for LCD display to the LCD device 25. Accordingly, the display controller 11 displays the LCD
The display timing signal for display is sent to the LCD device 25.
To supply.

Also, the BIOS 5 causes the display controller 11 to change to the LCD display mode.
And the contrast setting data 60a for LCD display which is held in advance is transmitted to the power supply microcomputer 21 via the GA9. The PWM register 7
0 has a 7-bit counter mode, and the transmitted contrast setting data 60a, for example, a binary number 11000.
111 is stored. It should be noted that the contrast setting data 60a for LCD display means the LC setting data in the LCD display mode.
This is a value that determines the contrast voltage value necessary for the D device 25 to display with the optimum contrast, and is held in advance. The power supply microcomputer 21 generates the PWM signal 55a from the contrast setting data 60a stored in the PWM register 70 and sends it to the filter circuit 23. The filter circuit 23 includes the PWM
The contrast voltage value is obtained based on the pulse width of the signal 55a and supplied to the LCD device 25.

The LCD device 25 displays the display data on the screen. The contrast of the display at this time is the contrast voltage transmitted from the filter circuit 23 and the LCD transmitted by the display controller 11.
Is determined by the relationship with the display timing signal.

Next, the case of changing from the LCD display mode to the simultaneous display mode will be described. When the user presses the hot key 15 twice in the LCD display mode, the KBC 17 detects that the hot key 15 has been pressed twice, and outputs a signal indicating a display mode switching request to the BIOS 5. Notify to. BIOS 5
Receiving this signal, recognizes that the LCD display mode has been changed to the simultaneous display mode.

In order to operate the LCD device 25 and the CRT device 33 in the simultaneous display mode, the BIOS 5 first sends a display timing signal to the display controller 11 for CRT display. The display timing signal of the LC
The D device 25 and the external CRT device 33 are instructed to transmit. According to this, the display controller 11 supplies the display timing signal for CRT display to the LCD device 25 and the external CRT device 33. In the case of simultaneous display, the display controller 1
The display timing signal transmitted by the LCD 1 is the LCD
Since it is necessary to make the display periods of one screen of the device 25 and the external CRT device 33 the same, the external CRT device 3
The display timing is supplied to the LCD device 25 in accordance with the display period of 3.

The BIOS 5 notifies the display controller 11 of the change to the simultaneous display mode, and transmits the contrast setting data 60b for simultaneous display, which is held in advance, to the power supply microcomputer 21 via the GA 9. . Since the PWM register 70 has a 7-bit counter mode, the transmitted contrast setting data 60b, for example, a binary number 10100.
110 is stored. The contrast setting data 60b for simultaneous display is a value that determines the contrast voltage value necessary for the LCD device 25 to display an optimum contrast in the simultaneous display mode, and is held in advance. The power supply microcomputer 21 generates the PWM signal 55b from the contrast setting data 60b stored in the PWM register 70, and the filter circuit 23
Send to The filter circuit 23 obtains a contrast voltage value based on the pulse width of the PWM signal 55b and supplies it to the LCD device 25. And the LC
The D device 25 displays the display data on the screen. The contrast of the display at this time is the relationship between the contrast voltage transmitted from the filter circuit 23 and the simultaneous display timing signal transmitted by the display controller 11. Determined by Further, the external CRT device 33 is determined according to the simultaneous display timing signal transmitted by the display controller 11.

According to the configuration of this embodiment, the BIOS 5 automatically generates the contrast setting data 60a or 60b for obtaining the optimum contrast in response to the change of the display timing signal due to the change of the display mode. Since it can be set, the optimum contrast can be obtained without the user having to reset the optimum contrast.

[0023]

As is apparent from the above description, when the user changes from the LCD display mode to the simultaneous display mode, the timing of the display timing signal shifts and the contrast of the LCD device deteriorates. Therefore, in order to obtain the optimum contrast, the BIOS transmits the contrast setting data to the PWM register of the power supply microcomputer so that the contrast does not change. Thus, by changing the contrast voltage value for the LCD device, it is possible to display the optimum contrast in the simultaneous display mode.

Therefore, according to the display mode selected by the user, the BIOS automatically discriminates the display mode and controls the contrast voltage value suitable for the display mode, so that the user can compensate for the deterioration of the contrast, and thus the LCD device is Optimal contrast can be obtained without manually operating, for example, a rotary switch or the like attached to the front surface or the side surface.

[Brief description of the drawings]

FIG. 1 is a system block diagram showing an electrical configuration of a portable electronic device to which an external CRT device of the present invention is connected.

FIG. 2 is a diagram showing a PWM register that stores a contrast setting command and a PWM signal that is generated.

FIG. 3 is a diagram showing a change in contrast in a conventional LCD display mode and a conventional simultaneous display mode.

[Explanation of symbols]

 1 ... CPU 3 ... RAM 5 ... BIOS 7 ... Power board 9 ... GA 11 ... Display controller 13 ... Keyboard 15 ... Hot key 17 ... KBC 19 ... .. C-MOS 21 ... Power supply microcomputer 22 ... PWM function 23 ... Filter circuit 25 ... LCD device 33 ... External CRT device 34 ... Connection terminal 55a, b ... PWM signal 60a, b ... Contrast setting data 70 ... PWM register

Claims (1)

[Claims] 1. A first display device comprising a first display device and a connector for connecting to an external CRT device, and a first display mode for displaying only on the first display device and the first display device and the connector. A portable electronic device capable of switching between a second display mode for simultaneously displaying an external CRT device and a second display mode according to a mode designation from a user, and a display timing signal for the first display mode and a display timing for the second display mode. The display control means for selectively generating a signal, the power supply control means for supplying power to the first display device based on the voltage determined by the content of the register, the respective modes and the first display device are suitable. Information indicating each voltage value for displaying in contrast is stored in advance in association with each other, and when a mode designation is received from the user, the designated mode is controlled by the display control. Notify the means,
A portable electronic device, comprising: a mode designating unit that reads out information indicating the voltage value associated with the designated mode and writes the information in the register.