JPH04366893A - Method and device for display - Google Patents

Abstract

PURPOSE:To provide display method and device capable of automatically switching a displayed optical output in response to peripheral illuminance. CONSTITUTION:The peripheral brightness of a display screen 2a is detected based upon power generated from a solar battery 4 for generating power from light based upon illuminance around the display screen 2a, and when the detected brightness is included within a prescribed range, the power from the battery 4 is controlled so as to be supplied to a power line.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display method and device, and more particularly to a display method and device that changes light output in response to changes in ambient illumination.

0002

2. Description of the Related Art Adjustment of display brightness, display density, etc. in a display device such as a CRT is generally performed manually by a user, and adjusting the display brightness is complicated. In particular, when the illuminance around the display device changes, the user must adjust the light output each time and adjust the brightness, density, etc. of the displayed screen to make it easier for the operator to see. I was adjusting.

0003

[Problem to be Solved by the Invention] For example, when displaying the background in white (bright) and the characters in black (dark) in the same way as printed matter, the display area of the white part becomes larger, so the display screen becomes larger. When the surrounding illuminance decreases, the display screen becomes relatively bright. This may cause glare and cause eye strain for the operator. In addition, for LCD devices with a backlight, the light output of the backlight appears to be relatively weak when the ambient illuminance of the display screen is high, so in some cases the backlight output may be turned off to utilize the ambient light. When used as a reflective display device, better results may be obtained, such as less eye fatigue for the operator. In response to such fluctuations in ambient illuminance, there has been a desire for a display device that can automatically adjust the brightness and density of a display screen without manual operation by the user. The present invention has been made in view of the above-mentioned conventional example, and it is an object of the present invention to provide a display method and device that automatically switches the light output of a display in response to ambient illuminance.

0004

Means for Solving the Problems In order to achieve the above object, a display device of the present invention has the following configuration. That is, a power generation means that generates power from light based on the illuminance around the display screen, a detection means that detects the brightness around the display screen based on the power generated by the power generation means, and a display section. and a control means for controlling the supply of electric power from the power generation means to the power supply based on the brightness detected by the detection means.

In order to achieve the above object, the display method of the present invention has the following configuration. That is, the process of inputting the light around the display screen to generate electric power, and determining the peripheral illuminance of the display screen based on the electric power, and when the peripheral illuminance is within a predetermined range, the process of generating electric power. and supplying power generated by inputting light to a power source for display.

[0006]

[Operation] In the above configuration, the brightness around the display screen is detected based on the power generated by the power generation means that generates power from light based on the illuminance around the display screen, and the detected brightness is detected. Based on this, the power generating means operates to control the supply of power from the power generating means to the power source that supplies power to the display section.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a top view of an electronic typewriter equipped with the display device of this embodiment. In FIG. 1, reference numeral 1 denotes a keyboard, which is operated by an operator to input document data, various function instructions, and the like. 2 is a display unit such as a liquid crystal display, which displays document data input from the keyboard 1,
Various messages to the operator are displayed. Reference numeral 3 denotes a printer section which prints out document data input from the keyboard 1. In this embodiment, a transflective liquid crystal display section 2a is used as the display section 2, and a backlight light source 5 (see FIG. 2) is provided behind the liquid crystal display section 2a. The backlight light source 5 emits light when displaying document data or the like on the display section 2 to illuminate the liquid crystal screen from the back side thereof. Further, a solar cell 4 is arranged around the liquid crystal display section 2a as indicated by diagonal lines in FIG. 1, and converts light energy around the display section 2 into electric power.

FIG. 2 is a diagram showing the AA' cross-sectional shape of the display section 2 shown in FIG. The light is emitted in the direction of the display surface (dotted arrow). Further, the solar cell 4 is provided on the outer periphery of the liquid crystal display section 2a, and generates electricity using optical energy from external light (thin line arrow), and supplies the generated electricity to the inside of the electronic typewriter.

FIG. 3 is a block diagram showing a schematic configuration of the display section 2 of this embodiment. In FIG. 3, the electromotive force from the solar cell 4 is transmitted to the display power line 40 via lines 31 and 32.
It is connected to the. This line 31 supplies power to a backlight inverter circuit 36 via a switch 34 and a diode D1 that can turn on/off the power supply of the power line 31 as necessary. This inverter circuit 36 is supplied with power from the main power supply 35 via a power supply line 40, and also has a diode D.
2 prohibits the flow of current in the direction of the power source 35, so the electromotive force from the solar cell 4 is applied in addition to the power from the main power source 35. Therefore, as the light energy received by the solar cell 4 increases, more power is supplied to the inverter circuit 36.

In this embodiment, AC-driven electroluminescence is used as the light source 5 for the backlight, so if the DC input voltage to the inverter circuit 36 is increased, the AC output voltage from the inverter circuit 36 is also increased. Become. As a result, as the ambient illumination increases, the illuminance of the backlight light source 5 automatically increases, allowing bright lighting.

Furthermore, since this embodiment uses a transflective liquid crystal display section 2a as the data display section 2, when the ambient illuminance of the display section 2 is sufficiently high, the backlight will stop emitting light. It is advantageous to use a reflective display. By doing this, the power consumed by the display unit 2 is transferred to the display drive circuit 38 based on the display control signal from the control circuit 39.
The only power consumed is the switching operation that is synchronized with the drive signal output from the drive signal. Therefore, the power consumption for light emission in the display section 2 is unnecessary, and the power consumption of the entire device can be kept low. .

On the other hand, when the ambient illuminance of the display section 2 is sufficiently low, the solar cell 4 applied to the inverter circuit 36
The electromotive force from the inverter circuit 36 becomes so small that it cannot contribute to the power supply to the inverter circuit 36. Therefore, in such a case, it is better to turn off the switch circuit 34 and use the power generated by the solar cell 4 to charge the battery 4 or to use it for backing up the memory of the control circuit 39, etc. It is valid.

The electromotive force of the solar cell 4 is converted by the detection circuit 37 as ambient illuminance information and inputted to the control circuit 39, so that the switching circuit 34 is turned on/off as described above.
The off operation can be realized by the control circuit 39 determining the ambient illuminance detected by the solar cell 4 based on the signal from the detection circuit 37 and outputting an on/off signal for the switch circuit 34 to the control line 33. .

FIG. 4 shows the operating conditions of the switch circuit 34,
3 is a diagram showing the relationship between the display unit 2 and the surrounding illuminance. FIG. In FIG. 4, the illuminance I detected based on the electromotive force of the solar cell 4
When X is in the range I1 < IX < I2, the power PA from the solar cell 4 is added to the power from the main power source 35 and supplied to the inverter circuit 36 . Further, when the detected illuminance IX is I1 ≧IX, it is determined that this electronic typewriter is in a dark room, and the switch circuit 3
Turn off 4. As a result, the power P from the solar cell 4
A is cut off, and only power from the main power source 35 for display is supplied to the inverter circuit 36.

When IX≧I2, it is determined that the electronic typewriter is placed in a sufficiently bright room (or outdoors during the day), and the switch circuit 34 is turned off. Furthermore, a main power supply 35 for display is connected by a control line 42.
By turning off, the power supply to the inverter circuit 36 is cut off, the backlight light source 5 is turned off, and the liquid crystal display section 2a is operated as a reflective liquid crystal display.

FIG. 5 shows the backlight light source 5 of this embodiment.
FIG. 2 is a diagram showing luminance characteristics of electroluminescence, which is an example of the electroluminescence. In FIG. 5, when the AC voltage that is the output of the inverter circuit 36 that is the power supply exceeds a certain level, the light emission output of the light source 5 starts to increase. Now, the brightness of the display unit 2 when in use is B1 ~ B2 (B1 < B2)
When set to , the operating AC voltage at that time is VAC-1 ~
VAC-2 (VAC-1<VAC-2). In other words, if the voltage of VAC-1 is set to be supplied by the main power supply 35 for display, and the voltage of the remaining voltage change [VAC-2-VAC-1] is supplied by the electromotive force from the solar cell 4, the back It becomes possible to cover changes in the brightness of the light source 5 with a small amount of electric power from the solar cell 4, and the brightness can be optimally adjusted in conjunction with the ambient illuminance.

FIG. 6 is a circuit diagram of the display power supply 35 of this embodiment. A main power source 35 for display, an inverter circuit 36 for backlight, and a solar cell 4 are connected as shown in FIG. The electromotive force of the solar cell 4 is input to the detection circuit 37 through lines 61 and 62, and its output level is detected by the control circuit 39. On/off of the switch circuit 34 is controlled by the control line 33 from the control circuit 39 as described above, and on/off of the power output of the main power source 35 for display is controlled by the control line 42.

FIG. 7 is a diagram showing a power supply circuit for display when an LED (light emitting diode) is used as a light source for a backlight as another embodiment of the present invention, and the common parts with FIG. 6 are as follows. They are indicated by the same number.

The combination of the inverter circuit 36 and electroluminescence as a backlight shown in FIG. 6 is replaced with an LED 71 and a current limiting resistor 72. By using a light diffusion plate, the light emission output from the LED 71 can be used as a backlight for the transflective liquid crystal display section 2a, as in the previous embodiment.

FIG. 8 is a flowchart showing the illuminance detection operation of the control circuit 39 of the display section 2 of the electronic typewriter of this embodiment. First, in step S1, an illuminance detection signal from the detection circuit 37 is input, and the peripheral illuminance of the display section 2 is detected based on the level of the detection signal. When the ambient illuminance is sufficiently bright, for example, it is checked whether the detected illuminance Ix is equal to or higher than I2 in FIG.
3 turns off the switch circuit 34. Thereby, the display section 2 becomes a reflective liquid crystal display. Also, step S2
If it is not bright enough, proceed to step S3, and display section 2
Check whether the surrounding illumination is low. When the illuminance is dark, for example, when the detected illuminance Ix is less than I1 in FIG. 4, the process proceeds to step S5, and the switch circuit 34 is turned off. As a result, the electromotive force output from the solar cell 4 is
The battery 4 is charged without being supplied to the battery 4.

Furthermore, when the ambient illuminance is neither dark nor sufficiently bright, for example, the light emission output variable range (I1 <
Ix <I2), the process proceeds to step S4, and the switch circuit 34 is turned on via the control line 33. As a result, the power generated from the solar cell 4 is transferred to the lines 31 and 32.
The power is supplied to the power line 40 via the power supply line 40, and can cover the power supplied to the inverter circuit 36.

[0022] In addition to the above-mentioned embodiment, even if the brightness change of other backlight light sources such as cold cathode tubes or the display unit depends on the power supply, the same method as in this embodiment can be applied. It is easy to adjust the light emitting output by changing it.

The present invention may be applied to a system made up of a plurality of devices, or to an apparatus made up of one device. It goes without saying that the present invention can also be applied to cases where the present invention is achieved by supplying a program for implementing the present invention to a system or device.

As explained above, according to this embodiment, the display device automatically changes the light emitting output in response to changes in ambient illuminance, increasing the light emitting output when the surrounding is bright and increasing the light emitting output when the surrounding is dark. Since the light emitting output can sometimes be linked to be reduced, the brightness of the ambient illuminance and display brightness can be maintained within a relatively optimized range. That is, it automatically adjusts for problems such as being too bright and dazzling for the user, or being too dim to read.

Furthermore, since a solar cell is used as a variable power supply for light emission output, and at the same time the electromotive force of the solar cell is detected as ambient illuminance, there is no need to provide a particular illuminance sensor, and the power consumption of the display device can be reduced. The transformation is measured.

Furthermore, by providing a switch circuit in the power supply for the light emitting output of the display device, in a backlit liquid crystal display, etc., the backlight power is automatically turned on and off depending on the ambient illuminance, and the light is emitted when the surrounding is bright. It has also become possible to turn it off and operate it as a reflective liquid crystal display device. The above-mentioned solar cell can detect ambient illuminance most effectively by placing it near the display device. In addition, since the power is supplemented by solar cells when the light output of the display is large, the device power source can be made smaller and lower in capacity.

[0027]

As explained above, according to the present invention, the light output of the display can be automatically switched in response to the ambient illuminance. This has the effect of eliminating the need for complicated switching.

[Brief explanation of drawings]

FIG. 1 is an external view of an electronic typewriter equipped with a display unit of this embodiment.

FIG. 2 is a sectional view of the display section of this embodiment.

FIG. 3 is a block diagram showing a schematic configuration of the electronic typewriter of this embodiment.

FIG. 4 is a diagram showing the relationship between the operating conditions of the switch circuit and ambient illuminance in this embodiment.

FIG. 5 is a diagram showing the luminance characteristics of electroluminescence, which is an example of a backlight used in this embodiment.

FIG. 6 is a circuit diagram showing an example of a display power supply circuit according to the present embodiment.

FIG. 7 is a circuit diagram showing another embodiment of the present invention when an LED backlight is employed.

FIG. 8 is a flowchart illustrating a control circuit for detecting illuminance and turning on/off power from a solar battery by a control circuit of a display section of the electronic typewriter of this embodiment.

[Explanation of symbols]

1 Keyboard 2 Display section 2a Liquid crystal display section 3 Printer section 4. Solar cells 5 Light source for backlight 34 Switch circuit 35 Main power supply for display 36 Inverter circuit 37 Detection circuit 38 Drive circuit 39 Control circuit

Claims (4)

[Claims] 1. A power generation means for generating power from light based on the illuminance around the display screen; and a detection means for detecting the brightness around the display screen based on the power generated by the power generation means. , a display comprising: a power supply that supplies power to the display section; and a control means that controls the supply of power from the power generation means to the power supply based on the brightness detected by the detection means. Device. 2. The control means controls the power generation means to stop supplying power to the power source when the illuminance detected by the detection means exceeds a predetermined value. The display device according to claim 1. 3. The display device is a transflective liquid crystal display device, and the control means turns off a power source for a backlight to prevent light reflection when the illuminance detected by the detection means is a predetermined value or more. 3. The display device according to claim 1, wherein the display device operates as a type liquid crystal display device. 4. A step of generating electric power by inputting light around the display screen, and determining peripheral illuminance of the display screen based on the electric power, and when the peripheral illuminance is within a predetermined range, A display method comprising the step of inputting surrounding light and supplying generated power to a power source for display.