JP2000111872A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to switch display modes with respect to a display device provided with a display panel permitting to display in plural display modes according to illuminance of external light. SOLUTION: When a timing signal is inputted from a timer 19, a CPU 11 refers to the detection result of a user holding state detection sensor 18 and judges whether or not the user is carrying a portable information terminal device 1 with him, and if the user carries it with him, the CPU makes a light source driving part 20 execute control of a light source in a light source part 21 based on the illuminance of external light measured by an illuminance sensor arranged in an illuminance sensor part 17, to adjust the brightness of the liquid crystal display screen of the liquid crystal display part 23 at the time of displaying to a proper state. Moreover, when the user holding state detection sensor 18 detects that the user is not carrying the portable information terminal device with him, the control of the light source of the light source part 21 is executed at longer time intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a control function for controlling the light emission luminance of a light source used in a transmissive or transmissive / reflective liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, as a display device provided with a non-light emitting type display panel such as a liquid crystal display panel, a transmission type device which performs display by using transmitted light emitted from a light source on the back side, and a display device having a light emitting type. Reflection-type display devices that perform display using reflected light that reflects reflected external light are mainly known. The transmissive display device can display with sufficient luminance even in a dark place, but has a drawback of large power consumption. Further, in the case of the reflection type, although the power consumption can be suppressed, there is a disadvantage that the screen is difficult to see unless the surrounding brightness is sufficient. As a display device that utilizes both of these advantages, a reflection / transmission type display device that uses both of them by switching is known.

[0003] The reflective and transmissive display device can perform display as a reflective type using external light when the surroundings are sufficiently bright, and use a light source when the surrounding brightness is insufficient. Thus, display can be performed as a transmission type. For this reason, especially when used in portable electronic devices used indoors and outdoors, it is possible to save battery consumption when used in bright places, and it is possible to display even in dark places, It was very convenient.

[0004]

However, in an electronic apparatus using a conventional reflective / transmissive display device, it is difficult to finely control the switching between the reflective and transmissive display methods, and the efficiency is high. Was bad. In other words, when switching between the reflective display mode and the transmissive display mode, a sensor for detecting brightness is provided, a detection result of external light illuminance is taken in from the sensor at predetermined intervals, and the display mode is switched according to the detection result. . If this switching is performed frequently, appropriate screen brightness is secured according to changes in external light, and a screen display that is very easy for the user to see can be provided.

However, the processing of detecting the external light illuminance and switching the display method according to the external light illuminance has been performed by executing a predetermined control program by the CPU of the electronic device having the above-described display device. Therefore, if the illuminance of external light is detected too frequently or the display method is switched, the load on the CPU of the electronic device increases.

[0006] Therefore, frequent switching of the display method of the display device according to the surrounding situation causes the other devices in the electronic device to be very slow, thereby deteriorating the convenience. It was difficult to finely control.

[0007] The present invention has been made in order to solve the above problems.
It is an object of the present invention to provide a display device having a display panel capable of performing display according to a plurality of display methods according to external light illuminance, so that switching of the display method can be finely and efficiently controlled.

[0008]

According to a first aspect of the present invention, there is provided a display device having a non-light emitting type display panel utilizing a light source and external light. Illuminance detection means for detecting the illuminance and outputting an illuminance detection signal, and detecting whether or not the display device is held by a user, and setting a time interval for controlling the light emission luminance of the light source according to the detection result. Control interval setting means, and for each time interval set by the control interval setting means, control means for controlling light emission luminance of the light source by an illuminance detection signal output from the illuminance detection means, I have.

Here, the control means controls the light emission luminance of the light source,
The adjustment is performed in a range from 0 (zero) to the maximum value that can be adjusted.
The control for turning on or off can also be executed.

Therefore, in the display device which adjusts the light emission luminance of the light source according to the illuminance of external light, the time interval for controlling the light emission luminance of the light source is set according to whether or not the main body is held by the user. When the illuminance of external light is apt to change, such as when the main body is being held by the user, and when it is necessary to frequently control the illumination means, the time interval for controlling the light source is shortened. In addition, the external light illuminance is stable when the main body is not held by the user and placed on a desk, etc.
When it is not necessary to frequently adjust the light emission luminance of the light source, the time interval for controlling the light source is increased. Therefore, the time interval of the control of the light source is changed as necessary, and unnecessary control is not performed, so that efficient control can be performed.
Since the control of the light source is performed frequently when necessary, the brightness of the display screen can be stabilized even in a state where external light is likely to change, and the convenience can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing a schematic internal configuration of a portable information terminal device 1 as an embodiment to which the display device of the present invention is applied. As shown in FIG. 1, a portable information terminal device 1 includes a CPU (Central Processing Unit) 1
1, RAM (Random Access Memory) 12, ROM (Re
ad Only Memory) 13, input unit 14, storage device 15, storage medium 16, illuminance sensor unit 17, user holding state detection sensor unit 18, clock device 19, light source drive unit 20, light source unit 2
1, a liquid crystal control unit 22 and a liquid crystal display unit 23, and these units are stored in a casing 10 (FIG. 4) described later.

When the power of the portable information terminal device 1 is turned on, the CPU 11 reads the basic control program stored in the ROM 13, develops the program in a work area provided in the RAM 12, and executes the program. Each unit of the apparatus 1 is controlled to shift to an initial state where processing can be started.
Further, the CPU 11 reads a control program or various application programs corresponding to the support from the ROM 13 or the storage device 15 in accordance with various instructions input via the input unit 14, develops the program in a work area in the RAM 12, and executes the program. The liquid crystal display unit 23 generates display information for causing a liquid crystal display screen included in the liquid crystal display unit 23 to execute display, outputs the display information to the liquid crystal control unit 22, and causes the liquid crystal control unit 22 to execute control of the liquid crystal display unit 23. A predetermined screen is displayed on the display screen.

Further, when a timing signal is input from the timing device 19 at predetermined intervals during execution of various programs, the CPU 11 executes a sensor confirmation process and a dimming process, which will be described later, as an interrupt process. When a detection result indicating that the portable information terminal device 1 is held by the user is input from the state detection sensor unit 18, the light source unit 21 is controlled based on the illuminance data input from the illuminance sensor unit 17. The illuminance to be turned on is determined, and instruction data is output to the light source driving unit 20 to control the light source unit 21.

The RAM 12 forms a memory area for temporarily storing various programs processed by the CPU 11 and data related to the processing.

The ROM 13 stores various programs such as a basic control program executed by the CPU 11 when the power of the portable information terminal device 1 is turned on. These various programs are stored in the form of program codes readable by the CPU 11.

The input device 14 has a touch pad provided integrally with the liquid crystal display screen of the liquid crystal display unit 23. This touch pad is configured by, for example, attaching a transparent panel in which transparent electrodes that are energized by a pressing operation are arranged in a matrix on the surface of a liquid crystal display screen. When the buttons corresponding to the buttons are pressed while the buttons corresponding to the character keys, the direction keys, the various function keys, and the various commands are displayed on the liquid crystal display screen, the position coordinates of the pressed portions are displayed. The input contents are specified by detecting the data, and data indicating the input contents is determined by the CPU 1.
Output for 1

The storage device 15 has a storage medium 16 in which various programs are stored. The storage medium 16 is magnetic,
It is composed of an optical recording medium or a semiconductor memory. The storage medium 16 is fixedly provided in the storage device 15 or is removably mounted on the storage device 15.
Various application programs executed by the CPU 11 and data related to these programs are stored.

The programs and data stored in the storage medium 16 may be received and stored from another device connected via a communication line or the like. It is also possible to provide a storage device provided with the above-mentioned storage medium on another device connected via the storage medium, and to use programs and data stored in the storage medium 16 via a communication line.

The illuminance sensor section 17 includes an illuminance sensor 17a for detecting ambient brightness.
Illuminance data indicating the ambient illuminance detected by 7a is C
Output to PU11. The illuminance sensor 17a includes a light receiving unit, and measures the illuminance of external light incident on the light receiving unit. Note that the illuminance sensor unit 17
It may output illuminance data at any time, or may output illuminance data in response to an instruction to output illuminance data from the CPU 11 when the instruction is input. .

The user holding state detecting sensor unit 18 includes a user holding state detecting sensor 18a for detecting whether or not the portable information terminal device 1 is in a user holding state held by a user. The detection result detected by the sensor 18a is output to the CPU 11. The user holding state detection sensor 18a includes a light receiving unit, detects whether the illuminance of external light incident on the light receiving unit is brighter or darker than a predetermined illuminance, and outputs the detection result to the CPU 11.
Output to Note that the user holding state detection sensor 1
The sensor 8a does not need to be a sensor capable of measuring the illuminance in the light receiving unit in detail, and has, for example, a sensitivity such that a state where the surface of the light receiving unit is covered is distinguished from a state where the surface is not covered. Just do it.

The time measuring device 19 measures time based on an oscillation signal obtained by an oscillating means such as a built-in crystal oscillator, and outputs a time measuring signal to the CPU 11 at predetermined time intervals. In addition, the clock device 19 may output a clock signal indicating the elapsed time from the start of the process,
Further, it may output a clock signal indicating the current time.

The light source driving unit 20 turns on the power of the light source unit 21 based on the instruction data input from the CPU 11.
The illuminance at the time of turning off the light source unit 21 is controlled.

The light source unit 21 has a light source installed behind or behind the liquid crystal display screen of the liquid crystal display unit 23. This light source is, for example, a light bulb, a fluorescent tube, or an EL.
(Electro Luminescent) elements. Then, the light source unit 21 turns on or off the light source at a predetermined illuminance according to the control by the light source driving unit 20.

The liquid crystal control section 22 executes control for displaying a screen on the liquid crystal display screen of the liquid crystal display section 23 based on the display data inputted from the CPU 11.

The liquid crystal display unit 23 has a transmission type liquid crystal display screen that transmits light, and the liquid crystal display screen is integrated with a light source of the light source unit 21 and a reflecting member for reflecting external light. Will be installed. In addition, the liquid crystal display screen can be configured as a touch panel 22a on which a touch pad of the input unit 14 is attached.

As an example of the configuration of the portion including the liquid crystal display section 23, for example, external light incident on the liquid crystal display screen is provided on the back of the liquid crystal display screen of the liquid crystal display section 23. A plurality of reflecting members that reflect in the direction from the front to the front are fixed, and the light source of the light source unit 21 is fixed so as to be located at the rear end of the liquid crystal display screen, or the entire rear surface of the reflecting member. The backlight type configuration in which the light source of the light source unit 21 is fixed so as to be located at the position indicated by. Among them, in the backlight type configuration, it is preferable that the reflecting member is configured by a semi-transmissive semi-reflecting plate that reflects external light and transmits light emitted from the back surface to the front surface of the reflecting member. . Also,
In the sidelight type configuration, it is preferable to provide a reflector, a light diffuser, or the like that irradiates light emitted from the light source of the light source unit 21 toward the rear of the liquid crystal display screen on the entire rear surface of the reflection member.

FIG. 2 is a flowchart showing a sensor confirmation process executed by the portable information terminal device 1. FIG. 3 is a flowchart showing the light adjustment processing in the sensor confirmation processing of FIG. 2 in more detail. Hereinafter, the operation of the portable information terminal device 1 will be described with reference to FIGS.

In the sensor confirmation processing shown in FIG.
U11 first substitutes 0 for a variable n (step S1).
1). Then, the CPU 11 checks the user holding state detection sensor 18 of the user holding state detection sensor unit 18 to check whether the portable information terminal device 1 is in the user holding state.
Reference is made to the detection result by a (step S12). Note that the processing in step S12 is performed by the timer 19
Is executed by the CPU 11 at predetermined time intervals, for example, every 2.5 seconds, in accordance with a clock signal input from the CPU 11 to the CPU 11.

Here, based on the detection result of the user holding state detecting sensor 18a of the user holding state detecting sensor unit 18 by the CPU 11, it is determined whether or not the portable information terminal device 1 is in a state of being held by the user. Is determined (step S13). If the portable information terminal device 1 is in the user holding state (step S13; Yes), 0 is substituted for a variable n (step S14), and a dimming process described later is executed (step S15). Thereafter, the CPU 11 executes the process of step S12 after a predetermined time has elapsed.

On the other hand, if it is determined in step S13 that the portable information terminal device 1 is not held by the user (step S13; No), the CPU 11
Increments the variable n (+1) (step S1).
6) It is determined whether the value of the variable n is 4 (step S17). If the value of the variable n has not reached 4, the process directly returns to step S12. If the variable n is 4, 0 is substituted for the variable n (step S18), and the dimming process described later is executed. Then (step S19), the process returns to step S12.

In the above sensor confirmation process, 2.5
It is determined every second whether or not the portable information terminal device 1 is in the user holding state. If it is continuously determined that the portable information terminal device 1 is not in the user holding state, the dimming process is executed when n = 4. Is done. When n = 4, 10 seconds have elapsed, and when the state where the portable information terminal device 1 is not held by the user continues, the CPU 11
The dimming process is executed every 0 seconds.

In the dimming process shown in FIG.
First, reference is made to a detection result obtained by detecting external light illuminance by the illuminance sensor 17a (step S21). Then, the external light illuminance detected by the illuminance sensor 17a is determined (step S22), and the external light illuminance is 10000 Lx (lux).
If so, the process proceeds to step S23, where the light source of the light source unit 21 is turned off.

The external light illuminance is 300 Lx to 10000
If it is within the range of Lx, the process proceeds to step S24, and the light source of the light source unit 21 is changed to, for example, the liquid crystal display unit 2.
3 is brightly lit so that the liquid crystal display screen of No. 3 is displayed with a luminance of about 100 nit (nit).

If the external light illuminance is less than or equal to 300 Lx, the process proceeds to step S25, in which the light source of the light source unit 21 is changed to a liquid crystal display screen of the liquid crystal display unit 23 having a luminance of about 50 nit (nit). Light up darkly as indicated by.

FIGS. 4A and 4B are views showing an example of an attached state of the user holding state detecting sensor 18a in the portable information terminal device 1, and FIG. 4A is a perspective view showing the front of the portable information terminal device 1. FIG. 2B is a perspective view showing a rear surface of the portable information terminal device, and FIG. 2C is a plan view showing a left side surface of the portable information terminal device 1.

As shown in FIG. 1A, a liquid crystal display screen of a liquid crystal display unit 23 is provided on the front surface of the housing 10 with a touch panel 22a having a touch pad provided on the input unit 14 on its surface.
It is attached as. Note that this touch panel 2
Each unit such as a light source unit 21 for performing display in 2a and a reflection plate is built in the housing 10.

An illuminance sensor 17a of the illuminance sensor 17 is attached to the upper right of the touch panel 22a on the front surface of the housing 10. The illuminance sensor 17a is attached so that its light receiving portion is exposed on the front surface of the housing 10, and can detect external light illuminance near the touch panel 22a.

As shown in FIGS. 4B and 4C, a user holding state detecting sensor 18a is attached below the left side surface of the housing 10 in a state where the light receiving portion is exposed on the surface of the housing 10. Have been.

In general, a portable electronic device provided with a touch panel as an input means is often used while being held by a user with one hand, such as outdoors or while moving, in addition to being used on a desk. When the user uses the housing 10 shown in FIG. 4 with one hand, the user uses the touch panel 22 as the dominant hand.
The case 10 is left empty for the input to a, and the housing 10 is supported by the non-dominant hand. That is,
A right-handed user will support and use the housing 10 with his left hand. Then, the user holding state detection sensor 18a
The lower part of the left side surface of the housing 10 to which is attached is a part that is hidden when the user supports the housing 10 with the left hand. When the right-handed user holds the housing 10 in his hand, the user holding state detection is performed. Since the light receiving portion of the sensor 18a is covered with a hand,
By referring to the detection result of the user holding state detection sensor 18a, it is possible to detect whether the housing 10 is in a state of being held in a hand.

Therefore, the user holding state detecting sensor 18a
As shown in FIG. 4, the portable information terminal device 1 is placed in a state where the illuminance of external light is likely to change while the portable information terminal device 1 is held by a user or used on a desk, as shown in FIG. Therefore, it is possible to easily determine whether or not the state is such that the change in the illuminance of external light hardly occurs.

As described above, according to the portable information terminal device 1 as an embodiment to which the present invention is applied, the illuminance is detected by the user holding state detection sensor 18a of the user holding state detection sensor unit 18 at predetermined time intervals. It is determined whether or not the portable information terminal device 1 is in the user holding state by detecting, and if it is determined that the portable information terminal device 1 is in the user holding state, the liquid crystal display screen of the liquid crystal display unit 23 is displayed. When the control of the light source unit 21 that performs illumination is performed and it is determined that the portable information terminal device 1 is not in the user holding state, it is further determined after a predetermined time that the portable information terminal device 1 is in the user holding state. I do. Thereby, while the portable information terminal device 1 is in the user holding state, the light source unit 2 is provided at short intervals.
If the portable information terminal device 1 is not in the user holding state, the control of the light source unit 21 is executed at longer time intervals.

Therefore, in the user holding state such as during movement where the illuminance of the external light is likely to change greatly, control processing for keeping the brightness of the liquid crystal display screen appropriate is frequently executed, and the user is not in the user holding state but in the state of putting on the desk. For example, when the external light illuminance is hard to change, the brightness of the liquid crystal display screen is controlled at long time intervals, so that the control of the display screen is executed without waste and the load on the CPU 11 of the portable information terminal device 1 is reduced. By reducing the power consumption, it is possible to prevent a reduction in the speed of various other processes executed by the portable information terminal device 1 while reducing waste of power consumption, thereby improving convenience.

In general, it can be said that an application program used while the portable information terminal device 1 is held by the user is an application program in which the load on the CPU 11 is relatively light. Therefore, even if the frequency of executing the dimming process (FIG. 3) in the user holding state, for example, while moving, does not impair the convenience in particular. on the other hand,
When the portable information terminal device 1 is used in a state where it is not held by the user, such as work on a desk, the application program being executed is likely to have a relatively heavy load on the CPU 11. Here, the convenience can be greatly improved by increasing the time interval at which the dimming process shown in FIG. 3 is executed.

In the above embodiment, when controlling the illuminance of the light source of the light source unit 21 based on the measurement result of the illuminance sensor 17a (step S22; FIG. 3), whether the illuminance of the external light is 10,000 Lx or more. , 300-10000
It is determined whether the value is within the range of Lx or 300 Lx or less. However, these numerical values are merely examples, and the present invention is not particularly limited to these numerical values. It is of course possible to perform the same processing on the basis of other numerical values according to the purpose of use, the intention of the user, and the like.

The shape of the housing 10 and the touch panel 2
There is no particular limitation on the configuration of 2a and each component, and any configuration may be used as long as it can be used in a hand. For example, the portable information terminal device 1 may include a liquid crystal display screen, a keyboard, and a pointing device. Of course, it is also possible to configure as a so-called notebook personal computer provided with the above. In this case, by attaching the user holding state detection sensor 18a to a portion covered by the user's hand when using the portable information terminal device 1 in his / her hand, the same effect as in the above embodiment can be obtained. is there.

Further, in the above embodiment, in order to detect that the portable information terminal device 1 is in the user holding state, the user holding state detecting sensor 18a for detecting whether or not the light receiving section is covered is used. However, another configuration may be provided in the user holding state detection sensor unit 18 to detect whether or not the portable information terminal device 1 is in the user holding state. Hereinafter, an example in which the contact type user holding state detection sensor 18b is used to detect whether the portable information terminal device 1 is in the user holding state will be described as a modification.

[Modification] A portable information terminal device 2 as a modification of the embodiment to which the display device of the present invention is applied will be described with reference to FIGS. The portable information terminal device 2 includes a contact-type user holding state detection sensor 18b as a sensor for detecting whether or not the user is in the user holding state in the user holding state detection sensor unit 18. The components of the portable information terminal device 2 other than the user holding state detection sensor unit 18 have the same configuration as that of the portable information terminal device 1 described above. And illustration and explanation are omitted.

FIG. 5 shows a user holding state detecting sensor unit 18.
3A is a plan view showing the configuration of a contact-type user holding state detection sensor 18b of FIG. 3A, wherein FIG. 3A shows a state where the sensor is installed on a plane, and FIG.

As shown in FIG. 5A, the contact type user holding state detecting sensor 18b is composed of an outer frame 181 and a contact rod 18
2, 183 and a moving ball 184, and the moving ball 1
84 is freely movable within the outer frame 181. Outer frame 18
Reference numeral 1 denotes a frame-like member having a rectangular cross section, which has a height sufficient to prevent the moving sphere 184 from going outside the outer frame 181.

The contact rods 182 and 183 are two rod-like members installed in parallel with the two sides of the outer frame 181 and across the other two sides of the outer frame 181. It is fixed to the outer frame 181 at the contact portion of the location. The contact rods 182, 183 have different thicknesses at two contact portions with the outer frame 181.
From the longitudinal center of 83 toward the contact part on the thick side,
It has a smoothly tapered portion. Moving ball 184
Is a sphere made of a conductor, which is stored in the outer frame 181 so as to be located between the contact rod 182 and the contact rod 183, and is freely movable.

The contact rods 182, 183 are made of a conductor, and the contact portions between the contact rods 182, 183 and the outer frame 181 are insulated. A continuity detecting circuit (not shown) is connected to the ends of the contact rods 182 and 183. The continuity detecting circuit is configured such that the moving ball 184 includes the contact rod 182 and the contact rod 183.
And outputs a detection signal when the contact rod 182 and the contact rod 183 are brought into conduction.

The contact type user holding state detecting sensor 1
8b, the contact type user holding state detection sensor 18
The plane on which b is attached is the bottom surface on which the moving ball 184 moves.
In order to detect the state of contact with the moving ball 184 more accurately, it is desirable that the surface layer of the bottom surface that the moving ball 184 contacts is insulated.

In the state shown in FIG.
Is a state in which no part of the outer frame 181 and the contact rods 182 and 183 are in contact. In this state, the contact rod 18
2 and the contact rod 183 are not electrically connected. Here, when the plane on which the contact type user holding state detection sensor 18b is attached is inclined in a predetermined direction, the moving ball 184 moves. FIG.
(B) is a figure which shows the state which the moving ball 184 moved and contacted the contact rod 182 and the contact rod 183. As shown in the drawing, when the contact-type user holding state detection sensor 18b is tilted, the moving ball 184 moves, and the contact rod 182 and the contact rod 1 are moved.
83 and abuts on the tapered portion. For this reason, since the contact rod 182 and the contact rod 183 are in a conductive state, the inclination of the contact type user holding state detection sensor 18b can be detected.

That is, the contact-type user holding state detecting sensor 18b determines the inclination of the plane on which the contact-type user holding state detecting sensor 18b is attached by using the contact rod 182 and the contact rod 1.
This is a sensor for detecting based on the state of conduction with 83.

FIG. 6 is a view showing an example of an attached state of the contact type user holding state detecting sensor 18b in the portable information terminal device 2 described above. FIG. 6A shows the portable information terminal device 2 placed flat on a horizontal plane. (B) shows a state where the portable information terminal device is tilted by 20 degrees with respect to the horizontal plane.

The housing 101 shown in FIG. 6 is the same housing as the housing 10 (FIG. 4) in the portable information terminal device 1, and has the user holding state detecting sensor 18a of the portable information terminal device 1 attached thereto. It differs from the housing 10 in that it does not have a hole on the left side.

As shown in FIG. 6A, a touch panel 22a is mounted on the front of the housing 101, and an illuminance sensor 17a is mounted on the upper right of the touch panel 22a on the front of the housing 101. . And
Inside the housing 101, a contact-type user holding state detection sensor 18b is attached to the back of the housing 101. In the state shown in FIG. 6A, since the housing 101 is placed flat on a horizontal plane, the moving sphere 184 of the contact-type user holding state detection sensor 18b stops and comes into contact with the contact rods 182 and 183. Therefore, the contact rod 182 and the contact rod 183 are not electrically connected.

FIG. 6B shows a state in which the housing 101 is inclined by 20 degrees with respect to the horizontal plane.
The moving ball 184 moves, and the contact rod 182 and the contact rod 1
It stops in a state where it comes into contact with the tapered portion 83. For this reason, the contact rod 182 and the contact rod 183 are brought into conduction, and this is detected by a conduction detection circuit (not shown) connected to the contact rod 182 and contact rod 183, and the case 10
It can be detected that 1 is tilted.

As described above, according to the portable information terminal device 2 as a modified example of the embodiment to which the present invention is applied, the outer frame 181 and the contact rod 1
82, a contact type user holding state detection sensor 18b composed of a contact rod 183 and a moving ball 184, and the contact rod 18 in the contact type user holding state detection sensor 18b.
By detecting the state of conduction between the portable information terminal device 2 and the contact rod 183, the inclination of the portable information terminal device 2 can be detected. When the portable information terminal device 2 is used in a state where the portable information terminal device 2 is placed on a flat surface, the portable information terminal device 2 is generally used indoors, such as on a desk, in a state where ambient brightness does not change much. It can be said that there is. On the other hand, if the portable information terminal device 2 is used in a tilted state, the portable information terminal device 2 may be used outdoors or in a state where the surrounding brightness is likely to change, such as in a state held in a hand. Conceivable. Therefore, in the portable information terminal device 2, by detecting the inclination of the portable information terminal device 2, when the surrounding brightness is likely to change, the illumination of the liquid crystal display screen of the liquid crystal display unit 23 is frequently controlled, In a state where the surrounding brightness is hard to change, it is possible to control the illumination of the liquid crystal display screen at longer time intervals, reduce the load on the CPU 11, reduce the power consumption, and increase the convenience.

In the modification of the above embodiment, the contact rod 1 of the contact type user holding state detecting sensor 18b is used.
Each of the contact rods 82 and 183 has a tapered portion that increases in thickness from near the center in the longitudinal direction to one end.
If the central portions 82 and 183 are configured such that the central portion in the longitudinal direction is the thinnest and the both ends are thick, and have a tapered portion that becomes thicker from the thinnest portion toward both ends, the mobile information terminal device 2 can be more efficiently formed. Tilt can be detected.

[0062]

According to the first aspect of the present invention, there is provided a display device for adjusting light emission luminance of a light source according to external light illuminance.
Since the time interval for controlling the light emission luminance of the light source is set according to whether or not the main body is held by the user, the illuminance of the external light may change, such as when the main body is moving while being held by the user. When the lighting means needs to be frequently controlled, the time interval for controlling the light source is shortened. Also, if the external light illuminance is stable when the main body is not held by the user and placed on a desk, etc., and it is not necessary to frequently adjust the light emission luminance of the light source, the light source control time Increase the interval. Therefore, the time interval of the light source control is changed as necessary, and unnecessary control is not performed, so that efficient control can be performed. Further, since the light source control is performed frequently when necessary, The brightness of the display screen can be stabilized even in a state where it is easy to change, and the convenience can be improved. In particular, when controlling a display device in a portable electronic device that can be used in a hand-held state, when using external light with fine control, power consumption is suppressed to save battery, When the external light is dark and the screen becomes difficult to see, the illumination by the illuminating means can be performed promptly to enhance the convenience. When the control of the light source is performed by using the computing device of the portable electronic device as the control means, the portable electronic device is held by the user, and when the load on the computing device is relatively light, the display device is frequently used. On the other hand, in a state where the portable electronic device is fixedly used and the load on the computing device is relatively heavy, the display device is controlled at a long time interval, so that the computing device is used efficiently,
And convenience is not impaired.

According to the second aspect of the present invention, there is provided grip light detecting means for detecting the illuminance of external light at a portion where the user's finger abuts during movement, and the grip external light detecting means is provided for the user. By detecting that the display device is covered with the finger, it is possible to easily detect that the display device is held by the user. Accordingly, it is possible to easily detect that the display device is held by the user, and to realize the display device at lower cost.

According to the third aspect of the present invention, the display device is held by the user by detecting whether the display device is on a plane or inclined, and the illuminance of external light changes. An easily accessible state can be more reliably and easily detected, and a display device that can be realized at low cost can be provided.

According to the fourth aspect of the present invention, a non-luminous display panel, a light source for irradiating light toward the back surface of the display panel, and external light incident on the display panel are applied to the back surface of the display panel. And a reflection unit that irradiates the light source, in the display device, since the time interval of the control of the light source is set depending on whether the display device is in a state of being held by the user, suppressing power consumption, In addition, in a display device that can display even in a dark place, by performing efficient control without impairing convenience, further efficiency and convenience can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a portable information terminal device as an embodiment to which the present invention is applied.

FIG. 2 is a flowchart illustrating a sensor confirmation process executed by the portable information terminal device of FIG. 1;

FIG. 3 is a flowchart showing a dimming process executed by the portable information terminal device of FIG. 1;

4A and 4B are diagrams illustrating a state of attachment of a movement sensor of the portable information terminal device of FIG. 1, wherein FIG. 4A is a perspective view illustrating a front surface of the portable information terminal device, and FIG. FIG. 2 is a perspective view showing a portable information terminal device, and FIG.

FIG. 5 is a plan view showing a configuration of a contact-type user holding state detection sensor included in a user holding state detection sensor unit in a portable information terminal device as a modification of the embodiment to which the present invention is applied; Indicates a state of being placed on a plane, and (b) indicates an inclined state.

6A and 6B are perspective views showing an attachment state of a contact-type user holding state detection sensor in the portable information terminal device of FIG. 5; FIG. 6A shows a state in which the portable information terminal device is placed on a horizontal plane; ) Indicates a state in which the portable information terminal device is tilted.

[Explanation of symbols]

 1, 2 portable information terminal device 10, 101 housing 11 CPU 12 RAM 13 ROM 14 input unit 15 storage device 16 storage medium 17 illuminance sensor unit 17a illuminance sensor 18 user holding state detection sensor unit 18a user holding state detection sensor 18b contact type User holding state detection sensor 181 Outer frame 182, 183 Contact rod 184 Moving sphere 19 Timing device 20 Light source drive unit 21 Light source unit 22 Liquid crystal control unit 23 Liquid crystal display unit

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Claims (4)

[Claims] 1. A display device comprising a non-light emitting type display panel using a light source and external light, an illuminance detecting means for detecting an illuminance of the external light and outputting an illuminance detection signal; Control interval setting means for detecting whether or not it is held by the user, and setting a time interval for controlling the light emission luminance of the light source according to the detection result; and for each time interval set by the control interval setting means. ,
And a control means for controlling the light emission luminance of the light source according to an illuminance detection signal output from the illuminance detection means. 2. A gripping portion light detecting means for detecting a light exceeding a predetermined illuminance at a portion of the gripping portion to which a user's finger abuts when the user moves the display device. The control interval setting means, when the light exceeding the predetermined illuminance is detected by the grip portion light detecting means, changes the setting of the time interval to a longer time, and detects the light exceeding the predetermined illuminance. The display device according to claim 1, wherein the setting of the time interval is changed to a shorter value when the setting is performed. 3. The apparatus according to claim 2, further comprising an inclination detecting means for detecting that the display device is inclined, wherein the control interval setting means sets the time interval when the inclination detecting means does not detect the inclination of the display device. 2. The display device according to claim 1, wherein the setting is changed to be long, and when it is detected that the display device is tilted, the setting of the time interval is changed to be short. 4. The display device according to claim 1, wherein the light source is a light source installed on a back side of the display panel and irradiating light toward the back surface of the display panel. 4. The display device according to claim 1, further comprising a reflection unit configured to irradiate a rear surface of the display panel with external light incident on the front side of the display panel and transmitted through the display panel. 5.