JP2002111865A - Electronic equipment having color liquid crystal display unit and method of illuminating the display unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electronic equipment having a color liquid crystal display unit of which visibility is improved and for which electric power is saved. SOLUTION: According to a combination of a plurality of comparison results of reference voltages (threshold values E1, E2, E3) set in multiple stage and outputs from an optical sensor 16 obtained by comparators 151, 152, 153, for example, when equipment is used in dark, normal brightness is provided by an LCD backlight 14. The light is turned off in the sunlight since light emission by the LCD backlight 14 is unnecessary. In a slightly dark place such as in the dusk, the light from the LCD backlight 14 is set to be a little brighter than normal. Furthermore, the light from the LCD backlight 14 is set to be the brightest in a slightly bright environment due to indoor light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic apparatus such as a portable telephone having a color liquid crystal as a display unit and a lighting method therefor.

[0002]

2. Description of the Related Art An electronic device having a transflective color liquid crystal as a display unit, for example, a portable telephone, is generally provided with a backlight for illuminating light and illuminating in a reflected light system so that the display can be viewed well in the dark. For example, the backlight is turned on for a certain period of time, for example, when the power is turned on, when a key is operated, or when an incoming call is received.

[0003]

The above-mentioned portable telephone has a high recognizability of the liquid crystal display in a dark place or a very bright place, but has a good recognizability in a slightly dark place such as at dusk or a slightly bright place with room light. Is very low. In addition, the backlight is turned on even when the surrounding environment is sufficiently bright and the display can be sufficiently checked even if the backlight is not turned on, so that the battery is wasted accordingly. Was.

The present invention has been made in view of the above circumstances, and determines the brightness of ambient light of a translucent color liquid crystal serving as a display unit in a predetermined state in a predetermined state such as at the time of an incoming call in multiple stages, and according to each stage. It is an object of the present invention to provide an electronic device having a color liquid crystal as a display unit, such as a mobile phone, which achieves optimal illumination by controlling the brightness of a backlight and saving power, and an illumination method therefor.

[0005]

According to a first aspect of the present invention, there is provided an electronic apparatus having a color liquid crystal having a backlight as a display unit, the electronic apparatus having a predetermined state. And a backlight control unit that determines the brightness of ambient light of the display unit in multiple stages in the predetermined state and controls the brightness of the backlight according to each stage. It is characterized by having.

According to a second aspect of the present invention, there is provided an electronic device having the color liquid crystal as a display unit according to the first aspect, wherein the electronic device is a portable telephone having a display unit and an operation unit integrated with each other, The state detection unit detects either a state at the time of an incoming call or a state at the time of operation by the operation unit.

According to a third aspect of the present invention, there is provided an electronic device having the color liquid crystal according to the first aspect as a display unit, wherein the electronic device comprises a display unit and an operation unit, and the display unit is opened when used. A foldable mobile phone that is set to a double-page spread state and is set to a closed state that covers the operation unit when not in use, wherein the state detection unit detects an open / closed state of the display unit.

According to a fourth aspect of the present invention, in the electronic device having the color liquid crystal according to the first aspect as a display unit, the backlight control unit detects ambient light of the display unit and adjusts its brightness. A light detection unit that outputs a corresponding voltage;
It comprises a plurality of comparators for comparing the predetermined reference voltage with the output voltage of the optical sensor, and a light emitting drive for determining the brightness of the backlight by a combination of the outputs of the comparators. .

According to a fifth aspect of the present invention, in the electronic device having the color liquid crystal according to the fourth aspect as a display unit, the optical sensor is a phototransistor or a photodiode.

According to the above configuration, according to the combination of each of the reference voltages (thresholds) set in multiple stages and the comparison result of the output from the optical sensor, for example, in an environment where the device is used in the dark, a normal backlight is used. It provides brightness and turns off the backlight because it is not necessary to emit light under sunlight, and in a slightly dark place such as dusk, the backlight light is set to be slightly brighter than usual, and furthermore, indoor light In a slightly bright environment, setting the backlight light as bright as possible improves the visibility of the color liquid crystal and saves power.

According to a sixth aspect of the present invention, there is provided a method of illuminating an electronic device having a color liquid crystal having a backlight as a display unit, wherein a predetermined state of the electronic device is detected and the display is performed in the predetermined state. The brightness of the ambient light of the unit is determined in multiple stages, and the brightness of the backlight is controlled according to each stage.

According to a seventh aspect of the present invention, in the lighting method of an electronic device having the color liquid crystal as a display unit according to the sixth aspect, in the predetermined state, the backlight has a predetermined brightness set in multiple steps. Then, the light is turned on, and the light is turned off after a predetermined time has elapsed.

According to an eighth aspect of the present invention, in the method of illuminating an electronic device having the color liquid crystal as a display unit according to the sixth aspect, the backlight has a predetermined brightness set in multiple stages in the predetermined state. And the backlight is turned off after a predetermined time elapses, detecting that the standby state has been changed.

[0014]

FIG. 1 is a block diagram showing an embodiment of an electronic apparatus according to the present invention having a color liquid crystal as a display section. Here, a mobile phone is exemplified as an electronic apparatus having a color liquid crystal (LCD) as a display unit.
As shown in FIG. 1, a mobile phone terminal includes an antenna (AN).
T) 1, 2, transmitting / receiving section (TRX) 3, control section 4, key switch 5, open / close detection switch 6, microphone 7, receiver 8, notification speaker 9, ROM 10, RAM 11, LC
It comprises a D driver 12, a color LCD 13, an LCD backlight 14, a backlight control unit 15, and a phototransistor 16.

The transmitting / receiving section 3 uses the antennas 1 and 2 to transmit / receive to / from a portable telephone base station (not shown). The transmission / reception unit 3 is controlled by a control unit 4 having a built-in microcomputer. The control unit 4 includes a key switch (operation unit) 5 operated when making a call, a microphone 7 and a receiver 8 for transmitting and receiving, Then, a notification speaker 9 for generating a ringtone upon reception is connected. The control unit 4 is further connected to a ROM 10 in which programs and character fonts are stored, and a RAM 11 that operates the programs stored in the ROM 10 or stores information sent from the base station. The control unit 3 further performs control to send display information to the LCD driver 12 and display desired data on the color LCD 13.

Usually, a portable telephone uses a transflective color LCD 13 as a display unit.
It is necessary to illuminate with the D backlight 14. Lighting is determined only for a certain period of time or through a light sensor such as a phototransistor or a photodiode, and is executed only when it is dark. The above-mentioned transflective color LCD 13 is provided in the mobile phone.
In addition to the integrated display unit and the operation unit including the key switch 5, the display unit is opened and set to the double-page spread state when in use, and set to the closed state to cover the operation unit when not in use and carried. There is a folding type. In the case of the foldable mobile phone, the display of the transflective color LCD 13 and the illumination of the LCD backlight 14 are performed only when the open / close detection switch 6 detects the open state of the display unit.

FIG. 2 shows a detailed configuration around the backlight control unit 15. In the drawing, blocks denoted by the same reference numerals as those in FIG. 1 are the same as those in FIG. The backlight control unit 15 includes comparators 151 and 15 forming a comparison unit.
2, 153 and an LED (light emitting diode) driver 154 serving as a light emission driving unit for determining the brightness of illumination by the LCD backlight 14.

One of the input terminals of each of the comparators 151, 152, 153 is commonly connected to an output obtained by dividing the output of the phototransistor 16 constituting the optical sensor by resistance (R1 and R2). The reference voltages E1, E2, and E3 having different voltage values are respectively supplied.
Here, the relationship between the reference voltage value serving as the threshold is represented by reference voltage E
It is assumed that 1 <reference voltage E2 <reference voltage E3. Limiting resistors R3, R4, R5 having the same resistance value are connected to the outputs of the comparators 151, 152, 153, respectively.
Here, according to the combination of the comparison result with each reference voltage, the LCD backlight 1 by the LED driver 154 is used.
4 is determined. That is, the backlight control unit 1 according to the output voltage of the phototransistor 16
Under the control of 5, the brightness of the illumination by the LCD backlight 14 is controlled. The LCD backlight 14 includes a backlight LED 141 and an LCD light guide plate 142.

FIGS. 2 and 3 are drawings cited for explaining the schematic operation of the embodiment of the present invention shown in FIGS. 1 and 2.
FIG. 9 is a diagram showing the relationship between the brightness of the external environment and the brightness of the LCD backlight 14 in the form of a graph in the control of the LED driver 154 in the form of a graph. According to the present invention, the illumination by the LCD backlight 14 provides normal brightness in the dark, and is turned off in sunlight because the LCD backlight 14 does not need to emit light. In a slightly dark place such as at dusk or in a slightly bright place with room light, the illumination of the LCD backlight 14 is made brighter than usual, thereby improving the visibility of the transflective color LCD 13 and saving power. I'm sorry.

Hereinafter, referring to FIGS. 3 and 4, FIG.
The operation of the embodiment of the present invention shown in FIG. 2 will be described. The phototransistor 6 installed to sense the brightness around the transflective color LCD 13 has a characteristic that a current flows when receiving light. A photodiode may be used instead of the phototransistor 6. This is taken in as a voltage value by resistance division by the resistors R1 and R2, and the divided voltage is commonly supplied to one input terminal of each of the comparators 151, 152, and 153. The comparator 1
51, the comparator 152, and the comparator 153 have the same characteristic, and the other input terminal has a reference voltage (reference voltage E1 <reference voltage E1) having a different threshold voltage value.
2 <reference voltage E3). Here, the result of the comparison is supplied to the LED driver 154. The LED driver 154 includes an open / close detection switch 6.
Opening / closing information from (detecting opening / closing of a foldable mobile phone) is also supplied through the control unit 4 (limited to a foldable mobile phone described later).

The LED driver 154 determines whether the control unit 4 indicates that the open / close detection switch 6 is in the "open" state, or that the mobile phone is in a call receiving state or that a key operation has been performed. , The backlight LED 141 in the LCD backlight 14 is driven, and the light of the backlight LED 141 enters the LCD light guide plate 142.

At this time, the LED driver 154
Is the backlight LED 1 according to the graph shown in FIG.
The drive current is output to 41. This is clearly shown in the table of FIG. FIG. 3 shows the magnitude of the backlight LED current on the vertical axis, that is, the backlight L current.
The emission intensity of the ED is scaled, and each comparator 15 is plotted on the horizontal axis.
The brightness of the illumination by the LCD backlight 14 according to the combination of the outputs 1, 152 and 153 is shown. According to FIG. 3, all of the comparators 151, 152, 153 are OF
In the case of F, the illumination by the backlight LCD 14 is set to be relatively dark by turning on the comparator 151, and the comparators 151 and 152 are turned on.
The backlight LCD 14 turns off the illumination when both are ON.
FF.

The relationship between the combination of the outputs of the comparators 151, 152 and 153 and the brightness of the external environment follows the table shown in FIG. That is, the illumination by the LCD backlight 14 provides normal brightness in darkness, and is turned off in sunlight because the LCD backlight 14 does not need to emit light. In a slightly dark place such as at dusk or in a slightly bright place with room light, the illumination of the LCD backlight 14 is made brighter than usual to improve the visibility of the transflective color LCD 13.

FIG. 5 is a flowchart showing the detailed operation of the embodiment of the present invention, and shows the operation of the backlight control unit 15 when a foldable portable telephone is exemplified as an electronic device having a color liquid crystal as a display unit. Less than,
1 to 4 with reference to the flowchart shown in FIG.
The detailed operation of the embodiment of the present invention shown in FIG.

In the flowchart shown in FIG. 5, first, the operation is started in step S201, and in step S2
At 02, it is determined whether the power of the mobile phone is ON. O
If N, it is determined in step S203 whether the mobile phone is in the open or closed state. If the display unit (color LCD 13) of the mobile phone is in the double-page spread state, and if it is "open", whether there is a call in step S204 (Incoming),
If a key operation has been performed, or the mobile phone has changed from the closed state to the open state, or if any of the three states has been met, the backlight control unit 15 determines the brightness in step S205.

In step S206, the comparator 15
1. If all of the comparator 152 and the comparator 153 are OFF, the brightness of the external environment is determined to be low based on the table shown in FIG. 4, and the brightness of the LCD backlight 14 is set to normal in step S210. In step S206,
If at least one of the three comparators is ON, the process proceeds to step S207. Step S207
When all of the comparators 151, 152 and 153 are ON, it is determined that the brightness of the external environment is fairly bright, and the LCD backlight 14 is turned off in step S210. In step S207, the comparator 151, the comparator 152, the comparator 1
If any of 53 is OFF, the process proceeds to the process of step S208.

If the comparator 151 and the comparator 152 are ON and the comparator 153 is OFF in the process of step S208, it is determined that the brightness of the external environment is slightly bright. A large current is supplied to the backlight LED 141 so that If the comparator 151 is ON and the comparator 152 and the comparator 153 are OFF in step S208, it is determined that the brightness of the external environment is slightly dark. A considerable current flows through the LED 141.

When the brightness of the illumination by the LCD backlight 14 is determined and executed in steps S210 to S213,
In step S214, the time is measured by the built-in timer,
Here, after 10 seconds have elapsed, the LCD backlight 14 is turned off in step S215. However, if the call (incoming call) has been received, a key operation has been performed, or the display unit of the mobile phone has been changed from the closed state to the open state before the elapse of 10 seconds, the process proceeds to step S204. The processing shifts to steps S205 to S205, and shifts again to the determination of the brightness of the illumination by the LCD backlight 14. The processing for determining the brightness is performed in steps S206 to S209, and the LCD backlight 14 is continuously turned on. However, in step S207, the comparator 151 and the comparator 15
2. If all of the comparators 153 are ON, it is determined that the external environment is very bright.
The backlight 14 is turned off.

FIG. 6 is a flow chart showing the operation of another embodiment of the present invention, and is a flow chart showing the operation of an integrated cellular phone in which the display unit and the operation unit are not foldable. Since the operation is the same as that of the foldable mobile phone shown in FIG. 5 except that there is no detection of the opening / closing of the display unit in step S203, detailed description is omitted in order to avoid duplication, but the same as in the embodiment shown in FIG. The LCD backlight 14 is turned on at a predetermined brightness set in multiple stages, and turned off after a predetermined time has elapsed.

FIG. 7 is a flow chart showing the operation of still another embodiment in the case where the transflective color LCD is turned on all the time during display by the backlight LCD 14 in order to further improve the visibility. The difference from the flowchart shown in FIG. 5 is that the interval of the timer of the elapsed time detection time in step S214 is narrowed (from 10 seconds to 5 seconds), and as step S216, a display timeout (return to the standby display) is provided before step S215. ) Is added, and if a timeout occurs in step S215, step S20
Jump to 5 and determine the brightness again. That is, in a predetermined state, the LCD backlight 14 is constantly turned on at a predetermined brightness set in multiple stages, and when the LCD backlight 14 is changed to a standby state, the LCD backlight 14 is turned off after a predetermined time elapses. It is characterized by the following.

In the embodiment of the present invention described above,
Although only a mobile phone has been exemplified as an electronic device having a color liquid crystal as a display unit, the present invention is not limited thereto.
A (Personal Digital Assistants), game consoles, etc.
The present invention can be applied to a relatively small electronic device in a similar manner.

[0032]

As described above, the present invention relates to an electronic apparatus having a color liquid crystal having a backlight as a display unit and an illumination method therefor, wherein a predetermined state of the electronic apparatus is detected and the predetermined state is detected. The brightness of the ambient light of the display unit is determined in multiple stages, and the brightness of the backlight is controlled according to each stage. Therefore, according to the combination of the comparison result of each of the reference voltages (thresholds) set in multiple stages and the output from the optical sensor, for example, in an environment where the device is used in the dark, the backlight provides normal brightness. However, it is not necessary to emit light from the backlight in sunlight, so the backlight is turned off.In a dark place such as dusk, the backlight light is set to be slightly brighter than usual, and in a slightly bright environment with indoor light. If so, you can set the backlight light as bright as possible,
As a result, the visibility of the color liquid crystal is improved, and power is saved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating a detailed configuration around a backlight control unit illustrated in FIG. 1;

FIG. 3 is a diagram cited for describing an operation of the embodiment of the present invention, and is a diagram in which control of an LED driver is expressed in a graph.

FIG. 4 is a diagram cited for explaining the operation of the embodiment of the present invention, and is a diagram showing a relationship between brightness of an external environment and brightness of illumination by an LCD backlight in a table format.

FIG. 5 is a flowchart cited for explaining the operation of one embodiment according to the present invention;

FIG. 6 is a flowchart cited for explaining an operation according to another embodiment of the present invention.

FIG. 7 is a flowchart cited for explaining an operation according to still another embodiment of the present invention.

[Explanation of symbols]

1 (2): Antenna (ANT), 3: Transmitter / receiver (TR)
X), 4 ... control unit, 5 ... key switch (operation unit), 6 ...
Open / close detection switch, 7 microphone, 8 receiver, 9 speaker for notification, 10 ROM, 11 RAM, 12 L
CD driver, 13 ... Color LCD (display unit), 14 ...
LCD backlight, 15 ... backlight control unit, 16
... Phototransistor (optical sensor), 141 ... LED for backlight, 142 ... Light guide plate for LCD, 151, 15
2, 153: comparator, 154: LED driver

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H04M 1/00 H04M 1/00 WF Term (Reference) 2H093 NA61 NA80 NC25 NC28 NC42 NC45 NC49 NC52 NC56 NC59 NC71 ND02 ND07 ND39 NG01 5C006 AA21 AF54 AF69 BB11 BF14 BF29 BF39 EA01 FA47 5C080 AA10 BB05 DD04 DD26 FF09 GG05 HH14 JJ02 JJ05 JJ07 KK07 5K027 AA11 BB01 BB17 CC08 FF02 FF22 GG03 MM08 HGG17MM

Claims (8)

[Claims] An electronic device having a color liquid crystal having a backlight as a display unit, comprising: a state detection unit that detects a predetermined state of the electronic device; and a brightness of ambient light of the display unit in the predetermined state. An electronic apparatus having a color liquid crystal as a display unit, comprising: a backlight control unit that determines the brightness in multiple stages and controls the brightness of the backlight according to each stage. 2. The electronic device according to claim 1, wherein the electronic device is a mobile phone in which a display unit and an operation unit are integrated, and the state detection unit detects one of a state when an incoming call is received and an operation when the operation unit is operated. An electronic apparatus having the color liquid crystal according to claim 1 as a display unit. 3. The electronic device includes a display unit and an operation unit, and sets the display unit to a double-page spread state during use.
2. The color liquid crystal display according to claim 1, wherein the foldable mobile phone is set to a closed state covering the operation unit when not in use, wherein the state detection unit detects an open / closed state of the display unit. An electronic device having as a display unit. 4. The backlight control unit detects an ambient light of the display unit and outputs a voltage corresponding to the brightness of the display unit, and outputs two or more predetermined reference voltages and an output of the optical sensor. The color liquid crystal display according to claim 1, comprising: a plurality of comparison units for comparing voltages; and a light emission drive unit for determining brightness of the backlight by a combination of the outputs of the comparison units. Electronic equipment to have. 5. The optical sensor according to claim 1, wherein the photosensor is a phototransistor;
An electronic device having a color liquid crystal as a display unit according to claim 4, wherein the electronic device is a photodiode. 6. A method for illuminating an electronic device having a color liquid crystal having a backlight as a display unit, wherein a predetermined state of the electronic device is detected, and the brightness of ambient light of the display unit in the predetermined state. The method for illuminating an electronic device having a color liquid crystal as a display unit, wherein the brightness of the backlight is controlled according to each stage. 7. The system according to claim 6, wherein in the predetermined state, the backlight is turned on at a predetermined brightness set in multiple stages, and is turned off after a predetermined time has elapsed. Lighting method for electronic equipment having a color liquid crystal as a display unit. 8. In the predetermined state, the backlight is always lit at a predetermined brightness set in multiple stages, and when the backlight is changed to a standby state, the backlight is turned on after a predetermined time has elapsed. An illumination method for an electronic device having a color liquid crystal as a display unit according to claim 6, wherein the illumination device is turned off.