JP2555319Y2 - Electronics - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic apparatus having a liquid crystal display and a lighting device disposed on the back of the liquid crystal display. A liquid crystal display is widely used as a display for a portable personal computer or the like, but has a problem that it is difficult to see in a dark place because the liquid crystal display is not a self-luminous type. . Therefore, for example, the magazine “PICO” 198
Vol. 1, No. As described in 9, P35, a method of arranging and illuminating EL on the back surface has been performed. However, since lighting devices such as EL consume a large amount of power, in portable electronic devices that are generally driven by a battery, there is a problem that if the lighting device is constantly turned on, the battery life is significantly reduced. [0004] Therefore, Japanese Utility Model Application Laid-Open No. 56-52793,
As disclosed in Japanese Patent Application Laid-Open No. 61-215588, if the keyboard is not operated for a certain period of time even during operation of the device, the lighting device is turned off, and if the keyboard is operated while the light is turned off. It has been considered to adopt a configuration in which the lighting device is turned on again. According to this configuration,
Since the lighting device is turned on only when necessary, power consumption can be greatly reduced. [0005] However, in such a device, the illumination device is turned off unless a key is operated for a predetermined time or more. For this reason, there is a problem in that when a user long considers while looking at the display surface, it is necessary to perform key operations periodically without necessity. SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and its structural features are a power supply for supplying a drive voltage to each unit and a drive from the power supply to each unit. A power switch for instructing voltage supply, a liquid crystal display, a lighting device for illuminating the liquid crystal display from behind, a keyboard for inputting data or control commands, and detecting operation on the keyboard or turning on of the power switch Means,
A counting means for generating an output when counting a predetermined time after reset, a predetermined key for instructing the lighting device to be constantly turned on,
Control means, the control means always turns on the illumination device when there is an instruction from the predetermined key, and responds to the detection of the detection means when there is no instruction from the predetermined key. Resetting the counting means, turning on the lighting device, and turning off the lighting device in response to an output from the counting means. According to this configuration, the user can arbitrarily select a mode in which the lighting device is turned off when the keyboard is not operated for a predetermined time or more, and a mode in which the lighting device is always turned on. An embodiment of the present invention will be described below with reference to the drawings using a personal computer as an example. FIG. 1 is a block circuit diagram showing an embodiment of the present invention. In FIG. 1, (1) is a control circuit constituted by a microprocessor, and a program in a program memory (2) in which a processing program is stored in advance. Each part is controlled in accordance with the following. (3) is a keyboard for inputting data or control commands. A key signal is input to the control circuit (1), and the control circuit (1) which has received the key signal performs a predetermined processing operation according to a program in the program memory (2). Do.
A memory (4) stores data input from the keyboard (3) or data processed by the control circuit (1), and the writing and reading of data are controlled by the control circuit (1). (5) is a liquid crystal display for displaying data input from the keyboard (3) or data processed by the control circuit (1), and has a display capacity of 80 characters × 25 lines. (6) EL disposed on the back of the liquid crystal display (5), which has the same size as the liquid crystal display (5) and emits surface light to illuminate the entire liquid crystal display (5) from behind.
(7) controls the supply of the driving voltage to EL (6),
A drive circuit for controlling the lighting of the EL (6), a booster circuit for boosting the voltage supplied from the battery power supply (8) to a drive voltage for the EL (6), and a EL (6) for varying the supply voltage to the EL (6). And a switch means for controlling the supply of a driving voltage to the EL (6) by a control signal from the control circuit (1). (1
0) indicates that key operation of the keyboard (3) has been performed;
The detection circuit detects that the power switch (11) is turned on and that the variable resistor (9) of the drive circuit (7) is operated, and supplies a detection signal to the control circuit (1).
(12) is a timer counter for counting the elapsed time, which is controlled by the control circuit (1) to count up and reset. (F1) and (F2) are flags provided in the control circuit (1), which are set or reset by a predetermined key operation of the keyboard (3), (F1) is a flag indicating that it is always lit, and (F2) is always. This is a flag indicating that the light is turned off. Next, the operation of this embodiment having the above configuration will be described with reference to the flowchart of FIG. First, as shown in FIG. 2, the control circuit (1)
The EL lighting control routine is entered from the main routine at a predetermined time interval (55 msec) by a timer interrupt to control EL lighting. When the power switch (11) is first turned on, power is supplied to each part and the liquid crystal display (5)
At the same time but in a display state, by detecting signal from the detecting circuit (10) is applied to the control circuit (1), step (S ₃₎ to determine the detection signal in the control circuit (1) to step (S ₄₎ after resetting the timer counter (12) advances, the control signal generated in the drive circuit (7) in step (S _5), and controlled to provide lighting the EL (6) with a drive voltage to the EL (6) . Next, proceeding to step (S ₆ ), the timer counter (12) is incremented by +1. At step (S ₇ ), it is determined whether or not the value of the timer counter (12) matches the set value, that is, at a predetermined time. A determination is made as to whether or not it has been reached. It is assumed that the designated time is set to 10 minutes in advance. Power switch (1
Since 10 minutes have not elapsed since the input of 1), the control circuit (1) returns to the main routine and performs other processing. During the other processing, the control circuit (1) also outputs E
The L (6) lighting control is monitored by entering the L lighting control routine and repeating the above operation. When a key is operated from the keyboard (3), the control circuit (1) displays the data inputted by the key on the liquid crystal display (5) and detects the data from the detection circuit (10) by the key input. A signal is detected, and step (S
_{In 3} ), the timer counter (12) is reset and the above operation is repeated. Therefore, as long as a key input is made from the keyboard (3), the timer counter (1
Since 2) is reset each time a key input is made, the predetermined time is not reached, the EL (6) is turned on, illuminates the liquid crystal display (5), and the displayed characters are easy to see. However, if the keyboard (3) is left without any key input, no detection signal is generated from the detection circuit (10), and the control circuit (1) proceeds to step (S).
Proceeds from ₃₎ to step (S _6), the timer counter (1
By counting up 2), the value of the timer counter (12) reaches the set value, the step (S ₈₎
Then, the driving circuit (7) is controlled to cut off the supply of the driving voltage to the EL (6), so that the EL (6) is turned off. However, other parts are still operating during this time, and the display is continuously performed on the liquid crystal display (5). The control circuit (1) also monitors the generation of the detection signal during this time, and when a key operation is performed on the keyboard (3) or the variable resistor (9) of the drive circuit (7) is operated to view the display. As described above, EL (6) is turned on by the generation of the detection signal. If you want to light constantly EL (6) dark surroundings is still, when the predetermined key operation from the keyboard (3), by the flag (F1) is set, the flag (F1 in step (S ₁₎ ), The control circuit (1) proceeds to step (S ₉ ) and always turns on the EL (6). If the surroundings are bright and the EL (6) does not need to be turned on, the control circuit (1) sets the flag (F2). ), The control circuit (1) proceeds from step (S ₂ ) to step (S ₈ ) to always turn off the EL (6). Although the embodiment has been described with reference to EL, the present invention is not limited to this and can be similarly applied to other lighting devices such as a cold cathode fluorescent lamp (CFT). According to the present invention, the lighting device is turned on not only in response to the operation on the keyboard but also in response to the operation of the power switch. Therefore, just by turning on the power switch,
Since the lighting device can be turned on for a predetermined time without any other operation, operability in a dark place is improved. In addition, since the lighting device is turned on at the same time as turning on the power switch, the normal operation of the device can be easily checked. Consumption can be prevented. Further, since the user can arbitrarily select the first mode in which the lighting device is turned off when the keyboard is not operated for a predetermined time or more and the second mode in which the lighting device is constantly turned on, the power consumption is reduced. In an operating environment where savings are the primary meaning,
In the case where it is necessary to select the second mode and listen while watching the display contents, the second mode may be selected, so that a convenient display state can be obtained according to the usage environment of the user.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block circuit diagram showing an embodiment of the present invention. FIG. 2 is a flowchart illustrating the operation of the embodiment. [Description of Signs] 1 control circuit 3 keyboard 5 liquid crystal display 6 EL 10 detection circuit 12 timer counter F1 flag

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Ryusuke Murayama               Bird, 3-201 Minamiyoshikata, Tottori City, Tottori Prefecture               Tori Sanyo Electric Co., Ltd.                (56) References JP-A-61-215588 (JP, A)                 Shokai Sho 56-52793 (JP, U)

Claims (1)

(57) [Rules for requesting registration of utility model] A power supply for supplying a drive voltage to each unit, a power switch for instructing supply of a drive voltage from the power supply to each unit, a liquid crystal display, a lighting device for illuminating the liquid crystal display from the back, and input of data or control commands A keyboard, a means for detecting operation of the keyboard or turning on of the power switch, a counting means for generating an output upon counting a predetermined time after reset, a predetermined key for instructing the lighting device to be constantly turned on, and a control means The control means always turns on the lighting device when there is an instruction from the predetermined key, while responding to the detection of the detection means when there is no instruction from the predetermined key, An electronic apparatus, wherein the counting device is reset, the lighting device is turned on, and the lighting device is turned off in response to an output from the counting device.