JP4073346B2 - Portable information equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a portable information device and a method for locking the device intended to prevent unauthorized use by a third party other than a specific user.
[0002]
[Prior art]
Mobile information devices that are frequently carried around, such as mobile terminals such as mobile phones and PDAs, mp3 players, and digital cameras are increasing. Many of such portable information devices have become multifunctional, and accordingly, a lot of personal information is accumulated (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-11-298635
[0004]
[Problems to be solved by the invention]
Since recent portable information devices store a lot of personal information, the damage caused by unauthorized use by a third party when the portable information device is lost is increasing.
[0005]
To deal with such problems, in services where usage is managed by a center such as a mobile phone, it is possible to take measures such as contacting the center when lost and disabling communication related services on the system side. Various personal information in the terminal cannot be protected.
[0006]
Therefore, in many portable information devices, a method of locking the function of the portable information device with a password is used. However, there were problems such as the possibility that the password could be canceled due to a brute force attack by a malicious third party who picked up the device, and the lock could not be released if the user forgot the password .
[0007]
Another measure is to wear a transmitter separate from the main unit and lock it when the distance between the transmitter and the main unit exceeds a certain level. There was a problem that the main body could not be operated.
[0008]
In addition, in the case of a portable information device driven by a built-in battery, it originally has the property that it cannot be operated when the battery runs out, but if a charger of the same model (or the same manufacturer) is used, it will not be possible to operate again. It can be charged and used.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a portable electronic device that can be used only for a predetermined period after charging and has improved safety when lost, and a locking method for the device. And
[0010]
[Means for Solving the Problems]
The portable information device of the present invention includes a time-varying part that changes with time without receiving power, and a time-change confirming part that measures the time-varying part to determine whether or not a predetermined period has passed and outputs the result. And a timer management means that outputs a notification to the effect that when a result of the determination output from the timer section indicates that a predetermined period has elapsed, referring to the timer section And a lock unit for storing information for prohibiting the operation of the own device when the output from the timer management unit is obtained, and for prohibiting the operation of the own device according to the stored information.
[0011]
Further, the portable information device of the present invention includes a timer unit capable of measuring a plurality of different periods by a plurality of time-varying units that change over time without obtaining power and exhibit different changes over time, and a plurality of the timer units. Selecting means for selecting any one of the time-varying part, a storing means for storing the selection result selected by the selecting means, and selecting the time-varying part with reference to the contents of the storing means when measuring the period. Timer management means for measuring the timer means.
[0012]
In addition, the present invention includes a storage unit that stores information indicating the operation or prohibition of the own device. When the stored information indicates prohibition, the lock unit for prohibiting the operation of the own device and power are obtained. When a timer unit capable of measuring a plurality of different time periods is selected by a plurality of time-changing units that change with time and exhibit different time-dependent changes, and when one of the plurality of time-changing units of the timer unit is selected A portable information device locking method comprising a timer management means for storing a result from the timer means for measuring a time-varying portion according to a selection result stored in the timer management means when measuring a period When the measurement result is obtained and the measurement result indicates that the period has elapsed, information indicating prohibition is stored in the storage unit of the lock unit, and the lock unit thereby prohibits the operation.
[0013]
In the present invention as described above, since the operation of the portable information device is selectively prohibited by the timer that operates without supplying power, it is restricted from being illegally used by a third party due to loss or the like. I can do it now.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 shows a functional block diagram of portable information device 1 and charger 2 according to the present embodiment.
The portable information device 1 refers to an information device that can be carried by a user and used as a subject, such as a notebook personal computer, a PDA, or a mobile phone.
[0016]
The portable information device 1 includes a CPU 11, a main memory unit 12, an input unit 13, a display unit 14, and the like. In addition to the main memory unit 12, the portable information device 1 includes a nonvolatile storage unit 15 such as an HDD or an EEPROM that stores various application software and secret information about individuals such as an address book.
[0017]
In addition, the portable information device 1 constantly changes its state without obtaining power, measures each state, and outputs a measurement result, and at least these timer units 16. −1 to n, the start of measurement of the timer 16-j selected in advance is controlled, and it is confirmed whether or not a predetermined period has passed by the output of the timer 16-j. Includes a timer management unit 17 that outputs the fact. Details of the timer units 16-1 to 16-n and the timer management unit 17 will be described later.
[0018]
In addition, the portable information device 1 includes a lock control unit 18 that locks the portable information device 1 so that the portable information device does not operate when receiving an output from the timer management unit 17 indicating that a predetermined period has elapsed.
[0019]
The portable information device 1 also includes a battery unit 20 that supplies power for driving the apparatus 1.
[0020]
Furthermore, when the portable information device 1 is connected to the external charger 2 to charge the battery unit 20, the portable information device 1 is connected between the authentication unit 19 in the portable information device 1 and the authentication unit 26 in the charger 2. Authentication is performed, and when the authentication is successful, the timer management unit 17 is notified. Note that any authentication method may be used as long as at least the portable information device 1 authenticates that it is a dedicated charger 2 for itself. Here, the charger 2 is used only for charging. However, when the user is in the office, the portable information device 1 is mounted on the device 1 in a dedicated docking station for charging, and the portable information device 1 is used when going out. It may be a dedicated docking station that is used alone.
[0021]
In addition, although not particularly illustrated, the portable information device 1 is a system that can be operated with application software or the like by operating from the battery unit 20 at all times, other than the timer units 16-1 to 16-n, for example. Of course, various functions for realizing a clock function and a function for communicating with the outside, for example, may be provided.
[0022]
The CPU 11, the main memory unit 12, the input / output unit 13, the display unit 14, the storage unit 15, the timer management unit 17, and the authentication unit 19 are connected to each other via a system bus 21.
[0023]
Next, the timer units 16-1 to 16-n will be described in detail. In this description, the description will be given focusing on one timer, and this timer is simply referred to as timer 16.
[0024]
FIG. 2 shows the basic configuration of the timer 16. The timer 16 includes a time change unit 31 and a time change confirmation unit 32. Here, the temporal change unit 31 changes its state with time without always supplying power, and the changed state can be used for measuring time. When the time change confirming unit 32 receives the enable signal from the timer managing unit 17, the time change confirming unit 32 measures the state of the time changing unit 31 and outputs a progress presence / absence signal indicating whether or not a predetermined period has elapsed to the timer managing unit 17. is there.
[0025]
FIG. 3 shows a time change unit 311 of the first specific example that realizes the time change unit 31.
[0026]
The time-varying portion 311 of the first specific example includes a source layer 51, a drain region 52, a first layer including a channel region 53 between the source region 51 and the drain region 52, and an upper portion of the first layer. The second layer is formed of a tunnel insulating film 54 stacked on the second layer, the third layer is formed of a floating gate 55 stacked on the second layer, and the insulating film 56 is stacked on the third layer. A fourth layer and a fifth layer including a control gate 57 stacked on top of the fourth layer are formed. A source electrode 58 and a drain electrode 59 are provided in the source region 51 and the drain region 52, respectively.
[0027]
FIG. 4 is a diagram showing a state change with time by the time-varying unit 311 of FIG. In the figure, gray circles indicate electrons and white circles indicate holes.
(A) is a figure which shows an initial state. As a pretreatment, the time-change unit 311 applies a high electric field between the control gate 57 and the substrate intermediary surface of the channel region 53 and the floating gate 55, and injects electrons from the channel into the floating gate 55 by FN tunneling. At this time, the substrate interfacing surface of the channel region 53 is inverted to concentrate holes, and a channel opens at the substrate interface of the channel region 53 between the source region 51 and the drain region 52.
[0028]
From this state (a), as time passes, electrons in the floating gate 55 directly tunnel to the substrate interface, and the electric field at the substrate interface of the channel region 53 gradually decreases. (B) is a time T after a certain time has elapsed from the state of (a). ₁ (C) shows a time T after a certain time has elapsed from the state (b). ₂ (D) shows a time T after a certain period of time has elapsed from the state of (c). _Three Shows the state. The dotted line schematically shows that the electrons have directly moved through the tunnel by that time. Time T _Three In the state (d), most of the electrons injected into the floating gate 55 are lost, and a channel is not formed at the substrate interface of the channel region 53. As a result, no output signal flows.
[0029]
FIG. 5 is a diagram showing the relationship between the time when the constant voltage is applied in the time-varying portion 311 and the current value. Time T _a (= 0) to T _b Direct tunneling occurs between the two, and finally the channel disappears and the current value decreases to the noise level. The time-varying unit 311 _a (= 0) to T _b Since a current corresponding to the state of change over time during (= noise level arrival time) flows, the time change confirmation unit 32 can determine whether or not a predetermined period has elapsed based on the value of the current. In addition, T on FIG. ₁ , T ₂ , T _Three Shows the states of (b), (c), and (d) of FIG. If different types of slopes of the relationship between the time and the current value of the time-varying unit 311 are prepared, each represents a different period. In order to obtain different shapes, it is sufficient to use ones having different charge amounts in the initial state or different amounts per direct tunnel time.
[0030]
FIG. 6 shows a time change unit 312 of a second specific example that realizes the time change unit 31 of FIG. The time-varying portion 312 of the second specific example includes a source layer 61, a drain region 62, a first layer including a channel region 63 between the source region 61 and the drain region 62, and an upper portion of the first layer. A second layer comprising a tunnel insulating film 64 laminated on the second layer, a third layer comprising a gate 65 laminated above the second layer, and a PN junction 66 for controlling a leakage current above the third layer; Formed with. A source electrode 68 and a drain electrode 69 are provided in the source region 61 and the drain region 62, respectively.
[0031]
The description of the state change with the passage of time of the time-varying unit 312 is the same as that of the first specific example if the direct tunneling in the description of the time-varying unit 311 of the first specific example is replaced with the leakage current of the PN junction. So it is omitted.
[0032]
FIG. 7 shows a time change unit 313 of a third specific example for realizing the time change unit 31 of FIG. The time-varying portion 313 of the third specific example includes a source layer 71, a drain region 72, a first layer including a channel region 73 between the source region 71 and the drain region 72, and an upper portion of the first layer. A second layer made of a tunnel insulating film 74 laminated on the third layer, a third layer made of a gate 75 laminated on the second layer, and a Schottky junction 76 for controlling a leakage current on the third layer. And formed with. A source electrode 78 and a drain electrode 79 are provided in the source region 71 and the drain region 72, respectively.
[0033]
The description of the state change with the lapse of time of the time-varying unit 313 is the same as the first specific example if the direct tunneling in the description of the time-varying unit 311 of the first specific example is replaced with the leakage current of the PN junction. So it is omitted.
[0034]
The time change unit 31 (211/212/213) described in detail above is connected to the time change confirmation unit 32.
[0035]
Next, a circuit configuration example of the temporal change confirmation unit 32 will be described with reference to FIG.
[0036]
The time change confirming unit 32 can apply a constant voltage to both ends of the time change unit 31. The source electrode 58/68/78 of the time-varying unit 31 is connected to the power supply terminal 81 side via the switch element 83, and the drain electrode 59/68 of the time-varying unit 31 is connected to the GND end 82 side via the ammeter 84. 69/79 is connected.
[0037]
The switch element 83 is connected to the enable signal line from the timer management unit 17, and when the enable signal is received, the switch block 83 is turned on and becomes conductive. The ammeter 84 measures a current value when a constant voltage is applied to the time-varying portion 31, and the measured current value is input to the comparison circuit 85. On the other hand, a predetermined threshold value is input to the other input of the comparison circuit 85. This threshold value is the current value at Tb described in FIG. The comparison circuit 85 compares the current value with the threshold value, and when the current value is large, the progress presence / absence signal becomes Low, and when the current value is small, the progress presence / absence signal becomes High. The progress / non-elapse signal of the comparison circuit 85 is supplied to the timer management unit 17.
[0038]
In such a circuit configuration of the time change confirmation unit 32, when the state of the time change unit 31 is confirmed, the switch element 83 is turned on by an enable signal from the timer management unit 17, and between the power supply terminal 81 and the GND terminal 82 Is applied with a predetermined voltage, the current flowing through the time-varying unit 31 is measured with an ammeter 84, and a progress signal indicating whether or not the measured current value exceeds a predetermined threshold is output. Thus, it can be determined whether or not a predetermined period has elapsed due to the change over time of the time change unit 31.
[0039]
The basic configuration of the timer 16 shown in FIG. 2 may be realized by a modification as shown in FIG. This modified configuration example provides a timer 16 with higher accuracy by providing m time-varying units 31 (m is a positive integer) having the same characteristics (measuring the same predetermined period) and averaging. Therefore, the temporal change confirmation unit 33 is slightly different in configuration from the above temporal change confirmation unit 32.
[0040]
An example of a circuit of the time change confirmation unit 33 in this modification is shown in FIG. In this example, the current values from the ammeters 84-1 to 84-m that measure the current values of the respective time-varying units 31-1 to 31-m are input to the averaging circuit 86 and averaged current values. Is compared with a threshold value by the comparison circuit 85 and a comparison result is output. By configuring in this way, even if there is some variation in each time change of the time change units 31-1 to 21-m, it can be provided as one timer 16 with higher accuracy by averaging.
[0041]
Next, the recharge unit 34 sets the time-varying unit 31 (31-1 to m) to an initial state, in other words, stores electrons in the floating gate 55 / gate 65/75. That is, the recharge unit 34 applies a high electric field between the floating gate 55 / gate 65/75 and the substrate intermediary surface as described above. The recharge unit 34 operates according to a signal from the timer management unit 17.
[0042]
When the timer units 16-1 to 16 -n of the timer 16 described above are mounted on the portable information device 1, for example, when each period as shown in FIG. 11 is to be set, each timer 16 having characteristics suitable for them. −1 to n may be arranged.
[0043]
Next, the timer management unit 17 will be described with reference to FIG.
[0044]
The timer management unit 17 includes a selection timer storage unit 41 that stores information indicating the timer 16-j selected by the user via the input unit 13. Here, the description will be made assuming that one timer 16-j designates, but different timers 16 may be selected for various functions, for example, a read function and a write function. For safety, it is desirable that the user can designate the timer 16-j only once, for example, at the time of purchase.
[0045]
In addition, the timer management unit 17 includes a timer table storage unit 42 that stores a timer table (see FIG. 13) in which the timers 16-1 to 16-n are associated with their measurement times. This is because the timer table stored in the timer table storage means 42 is read and displayed by the display unit 14 when the user selects a timer.
[0046]
When the timer management unit 17 receives the authentication success signal from the authentication unit 19, the timer management unit 17 instructs the timer units 16-1 to n to restart the time-varying units 31 (31-1 to 31-m). Is provided. The restart instruction is notified to the recharge unit 34 in the timer 16 described above.
[0047]
In addition, the timer management unit 17 includes a timer confirmation unit 44 that confirms whether or not the timer 16-j has elapsed for a predetermined period. The timer confirmation unit 44 outputs an enable signal to the timer 16-j based on information indicating the timer 16-j stored in the selection timer storage unit 41 when the power of the portable electronic device 1 is turned on. A signal indicating whether or not the timer 16-j has elapsed is obtained. If the passage presence / absence signal from the timer 16-j indicates that a predetermined period has elapsed, the lock unit 18 is notified of that fact.
[0048]
Next, the lock unit 18 will be described in detail.
[0049]
When the lock unit 18 receives a notification from the timer management unit 17 that a predetermined period has elapsed, the lock unit 18 stores the fact in an internal storage unit (not shown) and locks the portable information device 1. Various methods can be used for locking, but here, it is indispensable for the operation of main devices in the portable information device 1, for example, a portable information device such as a CPU, a main memory, and a power supply unit. The disable signal is output to at least one of the devices, and the device that has received the disable signal cannot use the portable information device 1. Instead of directly supplying the disable signal to the device, a switch may be provided on a line for supplying power from the battery unit to the device, and the switch may be turned off.
[0050]
Next, each operation | movement which concerns on this Embodiment of the portable information device 1 demonstrated above is demonstrated below.
[0051]
First, selection of the timer 16-j to be used will be described with reference to FIG. This designation may be incorporated as part of the initial setting when the user purchases the portable information device 1 and turns on the power for the first time, or at any timing after purchase, but only once. It may be possible to specify. It is desirable that it cannot be changed once specified.
[0052]
First, the mode setting screen of the timer unit 16 is displayed (S11). Here, the user designates the timer 16-j (S12). The screen display for designating the timer 16-j includes a display content for inquiring how many hours after the user removes it from the charger, and a designated input area from the user. For example, a first method in which several selection times are displayed and selected from among them, a second method in which direct input of time is specified, a third method in which a time axis is displayed and an arbitrary point on the axis is specified Possible methods. In the case of the first method, the timer table stored in the timer table storage unit 42 of the timer management unit 17 is referred to obtain the selected time and use it for screen display. The timer 16-corresponding to the selected time is used. What is necessary is just to determine j as the selected timer. In the case of the second method and the third method, the contents of the timer table are not directly related to the display. Therefore, the timer table may be referred to after obtaining the time specified by the user. Note that the second method and the third method may not always have a timer that matches the time specified by the user. In this case, the measured time of each timer in the timer table is compared with, for example, the nearest time. It is desirable to select and present it to the user for confirmation.
[0053]
Next, information indicating the timer 16 determined by the designation is stored in the selected timer storage unit 41 of the timer management unit 17 (S13). The selection timer storage unit 41 is an area that cannot be modified thereafter by the user.
[0054]
As described above, the timer 16-j used in the portable information device 1 is determined.
[0055]
Next, an operation for monitoring the availability of the portable information device 1 based on the selected timer 16-j will be described. This operation may be performed when the timer management unit 17 starts operating when the power of the portable information device 1 is turned on.
[0056]
When the timer monitoring operation is started, the timer management unit 17 reads information indicating the selection timer (= timer 16-j) stored in the selection timer storage unit 41 (S21). The timer management unit 17 outputs an enable signal to the timer 16-j based on the read information indicating the selected timer (S22).
[0057]
The time change confirming unit 32 (/ 33) turns on the internal switch 83 by the enable signal, measures the value of the current flowing through the time change unit 31 (/ 31-1 to m), and compares it with a threshold value to determine whether or not the progress has occurred. Is output (S23). The timer management unit 17 receives a progress presence / absence signal from the timer 16-j, and thereby obtains whether or not a predetermined period has passed (S24). If the predetermined period has not elapsed, the process ends without doing anything.
[0058]
On the other hand, when it is obtained that the predetermined period has elapsed, the timer management unit 18 notifies the lock unit 18 (S25). Then, the lock unit 18 stores the information and starts a lock function (S26).
[0059]
By doing in this way, it becomes possible to make it impossible to use an information apparatus after progress for a fixed time. By using the time-varying section here, it is possible to withstand an attack such as removing the battery (battery) and resetting the timer section 16.
[0060]
Next, the operation related to the start of measurement by the timer unit 16 will be described with reference to FIG.
[0061]
When the portable information device 1 is connected to the charger 2, the battery unit 20 is charged and an authentication process is performed between the authentication unit 19 and the authentication unit 26 to check whether the correct charger 2 is connected. (S31). For this authentication process, any method may be used as long as at least the authentication unit 26 can authenticate the authentication unit 19 as a dedicated charger 2.
[0062]
If this authentication fails as a result of the authentication process, the process ends without doing anything.
On the other hand, if the authentication is successful, an authentication success signal is output to the timer management unit 17 (S32).
When receiving the authentication success signal, the timer management unit 17 instructs the timer units 16-1 to n to restart (S33).
As a result, the time-varying units 31 (31-1 to 31-m) of the timers 16-1 to 16-n are set to the initial state and are restarted (S34).
In addition, the timer management unit 17 notifies the lock unit 18 (S35). As a result, if the lock unit 18 is locked, the lock is released (S36, S37).
[0063]
In the present embodiment described in detail above, by limiting the time during which the device can be used, if it is lost, further use by a third party can be prevented. Further, when authentication is performed between the authentication device and the information device main body and it is authenticated that the user is a valid user, the timer unit 16 can be reset.
[0064]
【The invention's effect】
According to the present invention, since the operation of the portable information device is selectively prohibited by the timer that operates without supplying power, the unauthorized use by a third party due to loss or the like can be restricted. Became.
[Brief description of the drawings]
FIG. 1 is a diagram showing functional blocks of a portable information device 1 according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a basic configuration of a timer 16;
FIG. 3 is a first specific example for realizing a time-varying unit 31;
FIG. 4 is a diagram showing a change in state over time by a time-varying unit 311;
FIG. 5 is a diagram showing a relationship between time and current value when a constant voltage is applied by a time-varying unit 311;
6 is a second specific example for realizing the basic concept of the time-varying unit 31. FIG.
FIG. 7 shows a third specific example for realizing the basic concept of the time-varying unit 31.
FIG. 8 is a circuit configuration example of a time change confirmation unit 32;
FIG. 9 is a diagram showing a configuration of a timer 16 of a modified example.
FIG. 10 is a circuit configuration example of a time-change confirming unit 23 according to a modification.
FIG. 11 is a measurement period example of each timer 16-1 to n.
FIG. 12 is a functional block diagram of the timer management unit 17;
FIG. 13 is an example of a table showing the correspondence between each timer 16-1 to n and the measurable elapsed time.
FIG. 14 is a flowchart when the timer 16-j is selected from the timers 16-1 to 16-n.
FIG. 15 is a flowchart for monitoring availability of the portable information device 1 based on a selected timer 16-j.
FIG. 16 is a flowchart including an operation related to the start of measurement by the timer unit 16;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Portable information device, 2 ... Charger, 11 ... CPU
12 ... main memory unit, 13 ... input unit, 14 ... display unit, 15, storage unit
16, 16-1 to 16-n: timer unit, 17 ... timer management unit
18 ... Lock part, 19 ... Authentication part, 20 ... Battery part
21 ... System bus, 26 ... Authentication unit, 27 ... Power supply unit
31, 31-1 to 31-m, 311, 312, 313...
32, 33 ... Time change confirmation part
51, 61, 71 ... source region
52, 62, 72... Drain region
53, 63, 73 ... channel region
54, 64, 74 ... Tunnel insulating film
55 ... Floating gate
56 ... Insulating film 57 ... Control gate
58, 68, 78 ... Source electrode
59, 69, 79 ... Drain electrode
65, 75 ... Gate 66 ... PN junction
76 ... Schottky junction
81, 81-1 to 81-m ... power supply end
82, 82-1 to 82-m ... GND end
83, 83-1-83-m... Switch element
84, 84-1 to 84-m ... ammeter
85 ... Comparison part
86 ... Averaging circuit

Claims (3)

A first layer including a source region, a drain region, and a channel region between the source region and the drain region; a second layer including a tunnel insulating film stacked on the first layer; and A third layer comprising a stacked gate; and a fourth layer comprising a Schottky junction above the third layer, and supplying electric power to the gate through the Schottky junction by supplying power; A time-varying portion in which the charge injected into the gate decreases with time without receiving power supply;
A time-change confirming unit that measures each current value of a plurality of time-varying units , compares a current value obtained by averaging the current values with a threshold value, determines whether or not a predetermined period has elapsed, and outputs the result Timer means comprising:
Referring to the timer unit, and when the result of the determination output from the timer unit indicates that a predetermined period has elapsed, timer management means for outputting that effect;
When the output from the timer management means is obtained, information for prohibiting the operation of the own device is stored, and lock means for prohibiting the operation of the own device according to the stored information is provided. Portable information equipment. Battery means for supplying power during operation;
Authentication is performed with an external charger connected when charging the battery means, and a signal indicating that is output when it is confirmed that the charger is compatible with the device as a result of the authentication. An authentication means,
2. The portable information device according to claim 1, wherein the timer management means initializes a time-varying portion of the timer means when receiving a signal from the authentication means. Battery means for supplying power during operation;
Authentication is performed with an external charger connected when charging the battery means, and a signal indicating that is output when it is confirmed that the charger is compatible with the device as a result of the authentication. An authentication means,
When the timer management means receives a signal from the authentication means, it notifies the lock means to that effect,
The lock means stores the stored information so as to change the information to enable the operation of the own device, and enables the operation of the own device according to the stored information. The portable information device according to claim 1.

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