JPH0437893A - Information apparatus - Google Patents

Abstract

PURPOSE:To attain gradation display inspite of a compact and light-weight apparatus by driving a display panel by binary display at the time of driving the apparatus by a built-in battery, and at the time of driving the apparatus by an external power supply, executing gradation display. CONSTITUTION:Switches 8, 9 can be switched in accordance with the existence of external power supply, and when the external power supply is not connected to a terminal 10, power is supplied from the battery 7 and the operation of a display control part 2 is simultaneously turned to a binary display mode. In this case, power is not supplied to a light source 6. When the external power supply is applied to the terminal 10, the power supply is switched from the battery to the external power supply and the control part 2 is turned to a gradation display mode. Since power is also supplied to the light source 6, a back-light lights up. Since the operation mode of the display panel is switched in accordance with battery/external power supply operation, long operation based upon the battery and a high function based upon gradation display can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an information device equipped with a power-saving multifunctional display device that is suitable for use in portable information devices.

2. Description of the Related Art In recent years, in the field of information equipment centered on computers, there has been an increasing demand for small, lightweight, battery-powered computers and word processors.

In this type of information equipment, a binary display liquid crystal panel is often used as a display device due to the need for small size and power saving.

-The display panels used for boat fishing are Twisted Yomachinku (TN) (Super Ricetent Fumachinoku).
STN)) Many of them use reflective liquid crystal.

There are also information devices that combine TN (STN) liquid crystals with light sources such as grasshopper lights to enable gradation display (Nikkei Electronics, ``Exploring the Future of Portable Computers J, April 1990, Nikkei BP company).

Problems to be Solved by the Invention However, in information equipment using a binary display panel,
There is a problem in that it cannot support gradation display, which is required in response to increased functionality.

In addition, information devices that use liquid crystal panels that can display gradations require a light source such as a backlight.
When powered by batteries, the operating time is short, and the built-in battery is also large, making it difficult to reduce the size and weight of the entire set.

The present invention solves the above-mentioned problems and provides an information device that is small and lightweight and can also support multi-functions such as gradation display.

Means for Solving the Problems In order to solve the above problems, the information device of the present invention operates the display panel in 2 (! display) when operated by a built-in battery, and enables gradation display when operated by an external power source. It is something.

A liquid crystal panel is used as the display panel, and it is desirable to use a ferroelectric liquid crystal panel.

Function: Due to the above-described configuration, the information equipment of the present invention operates with a binary display without using a light source such as a backlight, which consumes a large amount of power, and can operate for a long time when operating on a Wa battery, which requires low power consumption. On the other hand, when external power is supplied, gradation display is possible, visibility is improved using a backlight, and information equipment can be used with enhanced functionality. Then, a ferroelectric liquid crystal panel is used as the display panel, and by utilizing the memory effect of the ferroelectric liquid crystal panel, partial update display is performed in which only pixels or scanning lines that need to be rewritten are rewritten during binary display. This further reduces power consumption, and when displaying gradations,
Gradation display can be achieved by using a data thinning method based on full-screen scanning.

Embodiment Hereinafter, an information device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an information device according to an embodiment of the present invention, in which 1 is a display panel, 2 is a display control unit that controls the display panel, 3 is a display memory that stores display data,
4 is an arithmetic processing unit that performs various processes such as calculations, 5 is an input device such as a keyboard, 6 is a light source such as a bank light, 7 is a battery for power supply, 8 is a switch that changes the operation mode of the display control unit, and 9 is a Switches 7 and 10 for switching the power source between the battery and an external power source are external power terminals.

The operation of the information device according to an embodiment of the present invention configured as described above will be described below.

Switches 8 and 9 are switches that can be switched depending on the presence or absence of external power supply. When external power is not supplied to terminal IO, power is supplied from battery 7, and at the same time, the operation of display control unit 2 is set to binary display mode. do. In this case, no power is supplied to the light source. On the other hand, when external power is supplied to the terminal 10, the power source is switched from the battery to the external power source, and the display control section enters the gradation display mode. At the same time, power is supplied to the light source, so the bank light turns on.

FIG. 2 is a graph showing the driving voltage and optical response showing the operation of a ferroelectric liquid crystal display panel of an information device according to an embodiment of the present invention, and FIG. 2(a) shows the driving voltage applied to the pixels of the display panel. Voltage (b) shows the optical transmittance (reflection) with respect to the driving voltage.

In FIG. 2, it can be seen that the optical response of the ferroelectric liquid crystal can be controlled by the polarity of the applied voltage, and that even when the applied voltage is removed, the ferroelectric liquid crystal maintains its previous state. Therefore, by applying a rewriting voltage only to pixels (scanning lines) that require rewriting, high-speed display can be achieved with low power consumption.

FIG. 3 is a state diagram of display pixels showing gradation display operation of a ferroelectric liquid crystal display panel of an information device according to an embodiment of the present invention.
An example of 4-gradation display is shown. In Figure 3, 31,
32, 33, 34 indicate each pixel, 31 is black,
32 is dark gray, 33 is light gray, 34 is white, and 35, 36, and 37 are the first . Second.
The display pattern in the third field is shown. As is clear from FIG. 3, it can be seen that gradation display can be achieved by the difference between the black display time and the white display time.

Note that the configuration of the information device shown in FIG. 1 is only an example, and any device that can switch between binary display and gradation display in response to the supply of external power may be used.

Furthermore, it is not necessarily necessary to include a light source.

Furthermore, the drive voltage waveform of the ferroelectric liquid crystal panel shown in FIG. 2 is not limited to this, and the gradation display by the field thinning method shown in FIG.
Any device that displays intermediate tones based on the time difference between black display and white display may be used.

Effects of the Invention As described above, the present invention enables information equipment to operate for a long time on batteries and to achieve high functionality through gradation display by changing the operation mode of the display panel between battery operation and external power supply operation. This is something that can be realized.

Further, by using a ferroelectric liquid crystal display panel, it is possible to realize even lower power consumption in binary display, high-speed, high-quality display, and high-quality gradation display.

Furthermore, the device configuration does not become complicated due to gradation display, and a binary display panel can be used as is, and functions can be improved without increasing costs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an information device according to an embodiment of the present invention, and FIG. 2 shows driving voltage and optical response showing the operation of a ferroelectric liquid crystal display panel of an information device according to an embodiment of the present invention. The graph shown in FIG. 3 is a state V of a display pixel showing the gradation display operation of a ferroelectric liquid crystal display panel of an information device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Display panel, 2...Display control unit, 3...Display memory, 4...Arithmetic processing unit, 7...Battery, 8...Display mode switch, 9...Power selection switch, 10...
...External power supply terminal. Name of agent: Patent attorney Shigetaka Awano

Claims (5)

[Claims] (1) In an information device that is equipped with a display device capable of gradation display and a battery for power supply, and can be operated by the battery and an external power source, when the display device is operated by the battery, the display device has two values. An information device that operates with a display, and wherein the display device operates with a gradation display when external power is supplied. (2) The information device according to claim (1), wherein the display device uses a matrix type liquid crystal display panel. (3) The information device according to claim (2), wherein the liquid crystal display panel uses ferroelectric liquid crystal. (4) The information device according to claim 2 or 3, wherein the binary display uses a partial update display method in which only pixels (or scanning lines) that need to be rewritten are rewritten. (5) Any one of claims (2), (3), or (4), characterized in that the gradation display uses a display method that displays gradations by varying the lighting time of pixels. Information equipment described in .