JP2003069701A - Portable terminal equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To report timing to turn off the back light of a display part or operat ing part to a user, and to prevent erroneous operation caused by sudden turn of the back light, with respect to portable terminal equipment. SOLUTION: The non-operation time of a key switch 3 is counted by a timer 2 and when the non-operation time reaches the prescribed time, a microcomputer 1 lowers the luminance of a back light 6 by decreasing the current value of the back light 6 by controlling a current value switching circuit 8. At such a time, the ON of a key back light 9 is maintained. Thus, the user can obtain the timing to turn off the back light and the mulfunction can be prevented in operation for turning it on again.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mobile phone and a PDA.
The present invention relates to a mobile terminal device such as the above, and particularly to a control of a backlight for lighting a display unit and an operation unit.

[0002]

2. Description of the Related Art Generally, a display unit of a mobile terminal device such as a mobile phone or a PDA is composed of a combination of a liquid crystal display device and a backlight. The display on the liquid crystal screen can be made easier to see by turning on the backlight even in a dark place. Also, in many of the operation units of the mobile terminal device, a backlight is used in the same manner, so that an erroneous operation due to an operation in a dark place can be prevented.

However, since the battery mounted in the portable terminal device has a small capacity, the power consumption due to the lighting of these backlights cannot be ignored. Therefore, in the conventional mobile phone, it is important to prevent battery consumption due to unnecessary lighting of the backlight.

FIG. 9 is a block diagram of a conventional mobile phone disclosed in Japanese Patent Laid-Open No. 2001-103153. In the figure, 100 is a wireless communication processing unit that establishes communication with a wireless base station (not shown), 101 is an information processing unit that performs various types of information processing and control inside the mobile phone, 102 is a power supply, 10
Reference numeral 3 denotes a switch unit that switches power supply to each processing unit. Reference numeral 104 is a database, which is a telephone number, a name, and their connection type (voice call or data call).
Etc. are stored. Further, 105 is an input unit as an operation unit which is a user interface, and 106 is a display unit having a backlight.

This mobile phone determines whether the purpose of the call is a voice call or a data call before making a call at the time of making a call and at the time of receiving a call, and based on the determination, a display unit suitable for the purpose of the call is displayed. Power saving is realized by controlling the power supply.

FIG. 10 is a flow chart showing the operation of the conventional mobile phone shown in FIG. 9 when making a call. The operation of the conventional mobile phone will be described below based on this flowchart.

When a user inputs a telephone number from the input unit 105 when making a call to the other party (S100), it is determined based on the information in the database 104 whether the input telephone number is a voice call. Will be (S10
1). If the result of the determination is a voice call, a voice call connection process is performed (S102). If it is not a voice call, a data communication connection process is performed (S103), and then a data communication process is performed (S106). On the other hand, when the connection process of the voice call is performed, it is then determined whether or not the call is started (S104), and when the call is not yet started, the other party input waiting process is performed without performing anything. When the call is started, the power of the display unit 108 is turned off by the switch unit 103 shown in FIG. 9 (S105). Then, it is determined whether or not the call has ended (S107), and if not ended, the call is continued as it is, and when the call ends, the display unit 106 is turned on (S109).

As described above, when the connection type of the input telephone number is a voice call that does not require display, the backlight of the display unit is turned off, and data communication using the display unit such as a videophone and an electronic mail is performed. In this case, by continuing to turn on the backlight, it is possible to reduce power consumption due to unnecessary lighting of the backlight of the battery used in the mobile phone.

[0009]

In order to further reduce the power consumption of the battery, such a conventional mobile phone has a specification in which the backlight is automatically turned off after a certain period of time has passed since the input operation to the input section was lost. Has become. For example, the process of thinking about the text you enter as an email,
In the middle of reading the received e-mail, it often happens that no key operation continues for a long time, but even in that case, the backlight suddenly turns off. Further, in order to turn on the backlight that has been turned off again, it is necessary to perform a further key input operation to the input section.For example, when the operation is performed in a dark place, the key input operation for turning on the light again is dark. There is a risk that the text being edited or being read will be accidentally discarded due to a mistaken operation.

The present invention has been made in order to solve the above problems, and notifies the user of the timing of turning off the backlight of the display unit and the operation unit, and the backlight is suddenly turned off. It is an object of the present invention to provide a mobile terminal device capable of preventing an erroneous operation caused by.

[0011]

A portable terminal device according to claim 1 is a display unit, a first backlight for turning on the display unit, an operation unit to be operated by a user, and the operation. Detection means for detecting the operation of the unit, a timer for counting the non-operation time from the last detection of the operation, the first backlight is turned on upon detection of the operation, and the timer counts. And a light emission amount control means for controlling the light emission amount of the first backlight based on the non-operation time.

A portable terminal device according to a second aspect is the portable terminal device according to the first aspect, wherein the light emission amount control means is provided when the non-operation time reaches a predetermined first time. Decreasing the light emission amount of the first backlight to a predetermined value, and turning off the first backlight when the non-operation time reaches a predetermined second time longer than the first time. Is characterized by.

A portable terminal device according to a third aspect is the portable terminal device according to the second aspect, wherein the light emission amount control means is configured to perform the operation from the first time to the second time. It is characterized in that the light emission amount of the first backlight is reduced in multiple steps.

A portable terminal device according to a fourth aspect is the portable terminal device according to any one of the first to third aspects, wherein the first backlight is composed of a plurality of light emitting means. The light emission amount control unit controls the light emission amount of the first backlight by controlling the number of the light emission units to be turned on.

A portable terminal device according to a fifth aspect is the portable terminal device according to any one of the first to fourth aspects, further comprising a second backlight for turning on the operation section, and It is characterized by further comprising lighting control means for turning on the second backlight upon detection of an operation and turning off the second backlight at the timing of turning off the first backlight.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Preferred Embodiment> FIG. 1 is a configuration diagram of a mobile phone which is a mobile terminal device according to a first preferred embodiment of the present invention. In the figure, reference numeral 1 is a microcomputer of a mobile phone, 2 is a timer attached to the microcomputer 1, and 3 is a key switch which is an operation unit operated by a user. Reference numeral 4 denotes a key input decoder which operates as a detecting means for detecting an operation on the key switch 3, discriminates a key input by the operation, and notifies the microcomputer 1 of the information. 5 is a liquid crystal display unit, 6 is a backlight for turning on the liquid crystal display unit 5, 7 is a backlight drive circuit for turning on and off the backlight 6 under the control of the microcomputer 1, and 8 is a backlight under the control of the microcomputer 1. 6 is a current value switching circuit for switching the current value when lighting 6; That is, the microcomputer 1, the backlight drive circuit 7, and the current value switching circuit 8 constitute a light emission amount control means for controlling the light emission amount of the backlight 6.

Reference numeral 9 is a key backlight for turning on the key switch 3. 10 is a key backlight 9
Is a key backlight drive circuit for lighting and extinguishing, and is controlled by the microcomputer 1 so that the key backlight 9 turns on and off at the same timing as the backlight 6. That is, the key backlight drive circuit 1
0 and the microcomputer 1 constitute lighting control means for the key backlight 9.

FIG. 2 is a flowchart showing the control operation of the backlight 6 in the mobile phone according to this embodiment. FIG. 3 is a diagram showing the relationship between the current value of the backlight 6 of the mobile phone and time. The operation of the mobile phone according to the present embodiment will be described below with reference to these drawings.

When the user presses the key switch 3 of the mobile phone (S1), the key input decoder 4 detects it and notifies the microcomputer 1 of the information of the input key. Microcomputer 1
When receiving the information from the key input decoder 4, controls the backlight driving circuit 7, the current value switching circuit 8 and the key backlight driving circuit 10 to turn on the backlight 6 and the key backlight 9 (S2). At this time, the value of the current flowing through the backlight 6 is the current value switching circuit 8
Is set to a predetermined current value A shown in FIG. This allows the user to visually recognize the screen displayed on the liquid crystal display unit 5 and the key switch 3 which is the operation unit even in a dark place.

When the backlight 6 and the key backlight 9 are turned on, the microcomputer 1 then starts counting a predetermined time t1 by the timer 2 (S3). Then, it is determined whether the time t1 has passed (S4).
If the time t1 has elapsed at this time, the microcomputer 1 controls the current value switching circuit 8 to change the current value of the backlight 6 to a predetermined current value B (current value A> current value) as shown in FIG. Switch to B) (S5). That is, the light emission amount of the backlight 6, that is, the brightness is reduced. At this time, since the key backlight drive circuit 10 is not controlled, the key backlight 9 remains lit.

When the brightness of the backlight 6 is lowered at time t1, the microcomputer 1 then starts counting the predetermined time t2 by the timer 2 (S6). After that, time t
It is determined whether 2 has passed (that is, whether t1 + t2 has passed since the key operation was performed) (S7),
If the time has passed, the microcomputer 1 controls the backlight driving circuit 7 and the key backlight driving circuit 10 to set the current of the backlight 6 to 0 and turn off the backlight 6 as shown in FIG. The key backlight 9 is also turned off (S9).

If a key input operation is performed on the key switch 3 during the operation shown in the above flow chart, the flow immediately jumps to step S1 in any state of the flow. That is, the user performs the key input operation even after the time t1,
The current of the backlight 6 can be immediately set to the current value A, and the backlight 6 can be returned to the brightness before the time t1. When the key operation is performed and the jump to S1 is performed, the timer 2 is reset. As a result, the timer 2 is not operated after the last key operation on the key switch 3 is not performed. You are counting time.

As described above, in the mobile phone according to this embodiment, the time t1 before the backlight 6 is turned off.
In, the brightness of the backlight 6 decreases. Therefore, the user can perceive the elapse of the time t1 from the last key operation by the change in the brightness of the backlight 6, and the timing at which the backlight 6 is turned off soon.

When the user wants to restore the brightness of the backlight 6 to the original state and completely illuminate it, he or she may perform some key operation on the key switch 3. At this time, the backlight 6 is not completely turned off although the brightness is lowered, and the key backlight 9 is kept on until the backlight 6 is completely turned off. Part 5 and key switch 3
It is possible to operate while visually recognizing, and erroneous operation can be prevented.

<Second Embodiment> Hereinafter, in the second embodiment, the brightness of the backlight of the portable terminal device is controlled in multiple stages to smoothly change the brightness. The system configuration of the mobile terminal device according to the present embodiment is similar to that shown in FIG. 1 according to the first embodiment, and detailed description thereof is omitted here.

FIG. 4 is a flowchart showing the control operation of the backlight 6 in the mobile phone according to this embodiment. FIG. 5 is a diagram showing the relationship between the current value of the backlight 6 of the mobile phone and time. The operation of the mobile phone according to the present embodiment will be described below with reference to these drawings.

When the user presses the key switch 3 of the mobile phone (S11), the key input decoder 4 detects it,
The information of the input key is notified to the microcomputer 1. Upon receiving the information from the key input decoder 4, the microcomputer 1 controls the backlight drive circuit 7, the current value switching circuit 8, and the key backlight drive circuit 10 to turn on the backlight 6 and the key backlight 9 (S12). ). At this time, the value of the current passed through the backlight 6 is set to a predetermined current value A shown in FIG. 5 by the current value switching circuit 8.
This allows the user to visually recognize the screen displayed on the liquid crystal display unit 5 and the key switch 3 which is the operation unit even in a dark place.

After turning on the backlight 6 and the key backlight 9, the microcomputer 1 then starts counting a predetermined time t3 by the timer 2 (S13). Then, it is determined whether the time t3 has elapsed (S1).
4). If the time t3 has elapsed at this time, the microcomputer 1 controls the current value switching circuit 8 to decrease the current value flowing through the backlight 6 by a predetermined value dI as shown in FIG. 5 (S15). That is, the light emission amount of the backlight 6, that is, the brightness is slightly reduced. At this time, since the key backlight drive circuit 10 is not controlled, the key backlight 9 remains lit.

Next, the microcomputer 1 starts counting a predetermined time dt by the timer 2 (S16). Here, dt is a minute time such that dt <t3. Then, it is determined whether the time dt has elapsed (S17),
If the time has passed, the microcomputer 1 uses the current value switching circuit 8
Is controlled to further set the current value of the backlight 6 by a predetermined value dI as shown in FIG. 5 (S18).
As a result, the brightness of the backlight 6 is further lowered.

Next, it is determined whether or not the current value setting change in S18 has been performed a predetermined number of times n times (S1).
9). At this time, the number of times the current value setting is changed in S18 is n.
If the number of times has not been reached, the process returns to S16 again. Then, until the current value setting change in S18 reaches n times, S
16 to S19 are repeated.

Thereafter, in S19, if it is determined that the current value setting change in S18 has reached n times, the microcomputer 1 controls the backlight drive circuit 7 and the key backlight drive circuit 10 to show in FIG. Thus, the current of the backlight 6 is set to 0 to turn off the backlight 6, and the key backlight 9 is also turned off (S20). By the way, in this example, as a result of the current value setting change in S18 being performed n times, that is, the current value immediately before the backlight 6 is turned off (immediately before the time t1 + n × dt elapses after the key operation is performed) is (A−dI × n ).

If a key input operation is performed on the key switch 3 during the operation shown in the above flow chart, the flow immediately jumps to step S11 in any state of the flow. That is, the user can immediately set the current of the backlight 6 to the current value A to restore the backlight 6 to the brightness before the time t3 by performing the key input operation after the time t3. When the key operation is performed and the jump to S11 is performed, the timer 2 is reset. As a result, the timer 2 is not operated after the last key operation on the key switch 3 is not performed. You are counting time.

As described above, in the mobile phone according to the present embodiment, the time t3 before the backlight 6 is turned off.
After that, the brightness of the backlight 6 gradually decreases (in multiple steps). Therefore, the user can detect the timing when the backlight 6 is turned off due to the change in the brightness of the backlight 6. Further, when notifying the user of the turning-off timing, the brightness of the backlight 6 is gradually lowered without being sharply lowered, so that the turning-off timing can be notified while maintaining the visibility of the display screen as compared with the first embodiment. .

When the user wants to restore the brightness of the backlight 6 again and completely illuminate it, he or she may perform some key operation on the key switch 3. At this time, the backlight 6 is not completely turned off although the brightness is lowered, and the key backlight 9 is kept on until the backlight 6 is completely turned off. Part 5 and key switch 3
It is possible to operate while visually recognizing, and erroneous operation can be prevented.

<Third Embodiment> FIG. 6 is a block diagram of a mobile phone which is a mobile terminal device according to a third embodiment of the present invention.

In this figure, elements having the same functions as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted here. Reference numeral 20 denotes a backlight that lights up the liquid crystal display device 5 that is a display unit. The backlight 20 further includes 20a, 20b, and 20 respectively.
3 LEDs indicated by c (LED1, LED2, LED
3). Reference numeral 21 denotes an LED switching circuit that switches the LED to be turned on under the control of the microcomputer 1. Reference numeral 22 is an LED drive circuit that turns on and off each of LED1, LED2, and LED3 based on the LED switching operation of the LED drive circuit 21. That is, the microcomputer 1, the LED drive circuit 21, the LED switching circuit 22
This constitutes a light emission amount control means for controlling the light emission amount of the backlight 20.

FIG. 7 is a flowchart showing the control operation of the backlight 20 in the mobile phone according to this embodiment. FIG. 8 is a diagram showing the relationship between the lighting state of each LED constituting the backlight 20 of the mobile phone and time. The operation of the mobile phone according to the present embodiment will be described below with reference to these drawings.

When the user presses the key switch 3 of the mobile phone (S21), the key input decoder 4 detects it,
The information of the input key is notified to the microcomputer 1. Upon receiving the information from the key input decoder 4, the microcomputer 1 receives the LE
The D switching circuit 21, the LED driving circuit 22, and the key backlight driving circuit 10 are controlled to turn on the backlight 20 and the key backlight 9 (S22). At this time, the LED switching circuit 21 is controlled so as to turn on all of the LEDs 1, LED 2, and LED 3 constituting the backlight 20, as shown in FIG. This allows the user to visually recognize the screen displayed on the liquid crystal display unit 5 and the key switch 3 which is the operation unit even in a dark place.

After turning on the backlight 20 and the key backlight 9, the microcomputer 1 then starts counting a predetermined time t4 by the timer 2 (S23).
Then, it is determined whether the time t4 has passed (S2
4). If the time t4 has elapsed at this time, the microcomputer 1 controls the LED switching circuit 21 to turn off the LED 1 as shown in FIG. 8 (S25). That is, the light emission amount of the backlight 20, that is, the brightness is reduced. At this time,
Since the key backlight driving circuit 10 is not controlled, the key backlight 9 remains lit.

Next, the microcomputer 1 causes the timer 2 to start counting for a predetermined time t5 (S26). After that, it is determined whether or not time t5 has passed (that is, whether t4 + t5 has passed since the key operation was performed) (S27).
The D switching circuit 21 is controlled to turn off the LED 2 of the backlight 20 as shown in FIG. 8 (S28). As a result, the brightness of the backlight 20 is further reduced. At this time, no control is performed on the key backlight drive circuit 10.

Further, the microcomputer 1 causes the timer 2 to start counting for a predetermined time t6 (S29). After that, it is determined whether or not the time t6 has passed (that is, whether t4 + t5 + t6 has passed since the key operation was performed) (S30), and if it has passed, the microcomputer 1 controls the LED switching circuit 21. Then, the LED 3 of the backlight 20 is turned off as shown in FIG. by this,
The backlight 20 will be completely turned off. At this time, the microcomputer 1 controls the key backlight driving device 10 at the same timing to turn off the key backlight 9 (S31).

When a key input operation is performed on the key switch 3 during the operation shown in the above flow chart, the flow immediately jumps to step S21 in any state of the flow. That is, the user can immediately turn on all the LEDs of the backlight 20 to restore the brightness of the backlight 20 to the brightness before the time t4 by performing the key input operation even after the time t4. In addition, since the timer 2 is reset when a key operation is performed and jumping to S21, as a result, the timer 2 is a non-operation time during which no key operation is performed after the last key operation on the key switch 3 is performed. Is being counted.

As described above, in the mobile phone according to this embodiment, the time t before the backlight 20 is turned off.
After 4, the brightness of the backlight 20 is reduced by reducing the number of the plurality of LEDs that make up the backlight 20 to be lit. Therefore, the user can detect the timing when the backlight 20 is turned off due to the change in the brightness of the backlight 20.

When the user wants to restore the brightness of the backlight 20 to the original state and turn it on completely, he or she may perform some key operation on the key switch 3. At this time, the backlight 20 is not turned off completely although the brightness is lowered, and the key backlight 9 is kept turned on until the backlight 20 is completely turned off. The operation can be performed while visually recognizing the portion 5 and the key switch 3, and an erroneous operation can be prevented.

Although the three LEDs constituting the backlight 20 are turned off one by one in this example, the method of reducing the brightness of the backlight is not limited to this. Only one of the three LEDs is turned off after a predetermined time has passed from the last key operation,
After that, the remaining two lights may be turned off at the same time after a lapse of a predetermined time.

In the present embodiment, the number of LEDs constituting the backlight 20 is three, but it is clear that the same effect can be obtained if the number of LEDs is two or more. Further, when the number of LEDs that constitute the backlight 20 is three or more, the backlight 20
It is possible to gradually (in multiple steps) change the luminance, and it is possible to notify the turn-off timing while maintaining the visibility of the display screen as compared with the first embodiment.

In the above description, as a portable terminal device having a backlight function in the display section and the operation section,
Although a mobile phone is shown as an example, the scope of application of the present invention is not limited to this, and it goes without saying that the present invention can be widely applied to other mobile terminal devices such as a PDA.

[0048]

According to the portable terminal device of the first aspect, the detecting means for detecting an operation on the operation portion, the timer for counting the non-operation time from the detection of the last operation, and the operation detection. Accordingly, the first backlight that lights the display unit is turned on, and a light emission amount control unit that controls the light emission amount of the first backlight based on the non-operation time is provided. The change can notify the user of the non-operation time, and the user can
You can detect the timing when the back light turns off.

According to the portable terminal device of the second aspect,
The portable terminal device according to claim 1, wherein when the light emission amount control means reaches a predetermined first time,
The first backlight is turned off when the light emission amount of the first backlight is reduced to a predetermined value, and when the non-operation time reaches a predetermined second time longer than the first time, the first backlight is turned off. The decrease in the brightness of the backlight can notify the user that the non-operation time has elapsed, and the user can detect the timing (second time) when the first backlight is turned off.

According to the mobile terminal device of the third aspect,
The mobile terminal device according to claim 2, wherein the light emission amount control means reduces the light emission amount of the first backlight in multiple stages from the first time to the second time, so that the display screen is visually recognized. The change in the brightness of the first backlight can notify the user of the timing (second time) when the first backlight is turned off without significantly impairing the performance.

According to the portable terminal device of the fourth aspect,
The portable terminal device according to any one of claims 1 to 3, wherein the first backlight includes a plurality of light emitting means, and the light emission amount control means controls the number of light emitting means to be turned on. Since the light emission amount of the first backlight is controlled, the user can detect the timing at which the first backlight is turned off by the change in the brightness of the first backlight.

If the first backlight is composed of three or more light emitting means, the brightness of the first backlight can be changed in multiple steps. As a result, the first screen can be displayed without significantly impairing the visibility of the display screen.
The user can be notified of the timing of turning off the first backlight by the change in the brightness of the backlight.

According to the portable terminal device of the fifth aspect,
The mobile terminal device according to any one of claims 1 to 4, further comprising: a second backlight that lights the operation unit; and a second backlight that lights when the operation is detected, and the first backlight. Since the lighting control unit that turns off the second backlight at the timing of turning off the backlight is provided, the visibility of the operation unit is maintained even when the brightness of the first backlight is changed. Therefore, the user can perform an operation to restore the lowered brightness of the first backlight while visually recognizing the display unit and the operation unit, and prevent an erroneous operation due to the operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a mobile phone according to a first embodiment.

FIG. 2 is a flowchart showing a backlight control operation in the mobile phone according to the first embodiment.

FIG. 3 is a diagram showing a relationship between a current value of a backlight of the mobile phone according to the first embodiment and time.

FIG. 4 is a flowchart showing a backlight control operation in the mobile phone according to the second embodiment.

FIG. 5 is a diagram showing a relationship between a current value of a backlight of the mobile phone and time according to the second embodiment.

FIG. 6 is a configuration diagram of a mobile phone according to a third embodiment.

FIG. 7 is a flowchart showing a backlight control operation in the mobile phone according to the third embodiment.

FIG. 8 is a diagram showing a relationship between a lighting state of each LED constituting the backlight of the mobile phone according to the third embodiment and time.

FIG. 9 is a configuration diagram of a conventional mobile phone.

FIG. 10 is a flowchart showing an operation of a conventional mobile phone at the time of making a call.

[Explanation of symbols]

1 microcomputer, 2 timer, 3 key switch, 4
Key input decoder, 5 liquid crystal display, 6, 20 backlight, 7 backlight drive circuit, 8 current value switching circuit, 9 key backlight, 10 key backlight drive circuit, 20a, 20b, 20c LED, 21 LE
D switching circuit, 22 LED drive circuit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Daisuke Nakamura             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F term (reference) 5B011 DA01 EA02 EB09 KK02 KK04                       LL15                 5K027 AA11 BB17 FF22 GG08 HH30                       MM16                 5K067 AA26 AA43 BB04 CC21 EE02                       FF05 FF24 FF31

Claims (5)

[Claims] 1. A display unit, a first backlight for turning on the display unit, an operation unit to be operated by a user, detection means for detecting the operation on the operation unit, and the last one. A timer that counts the non-operation time from the detection of the operation, and turns on the first backlight in accordance with the detection of the operation, and the first backlight is turned on based on the non-operation time counted by the timer. A mobile terminal device, comprising: a light emission amount control unit that controls a light emission amount. 2. The portable terminal device according to claim 1, wherein the light emission amount control means emits light from the first backlight when the non-operation time reaches a predetermined first time. To a predetermined value, and turns off the first backlight when the non-operation time reaches a predetermined second time longer than the first time,
A mobile terminal device characterized by the above. 3. The portable terminal device according to claim 2, wherein the light emission amount control means is configured to perform the first time period from the first time to the second time.
The mobile terminal device is characterized in that the light emission amount of the backlight is reduced in multiple stages. 4. The mobile terminal device according to claim 1, wherein the first backlight includes a plurality of light emitting means, and the light emission amount control means includes the light emitting amount control means. A portable terminal device, wherein the light emission amount of the first backlight is controlled by controlling the number of light emitting means to be turned on. 5. The mobile terminal device according to claim 1, further comprising a second backlight that lights the operation unit, and the second backlight that is detected when the operation is performed. A mobile terminal device, comprising: a lighting control unit that turns on the backlight and turns off the second backlight at the timing of turning off the first backlight.