Portable terminal device

A portable terminal device 101 of the invention having at least two or more cases joinable in a plurality of different joining shapes includes a magnetism detection section 8 being provided in at least one of the two or more cases for detecting a magnetism quantity; a storage section 9 for storing the effect amount produced by magnetism from a magnetism generation source of the portable terminal device 101 in the detected magnetism quantities for each of the plurality of different joining shapes of the portable terminal device 101; a case shape detection section 4 for detecting a joining shape of the portable terminal device 101; a data processing section 3 for correcting the detected magnetism quantity based on the stored effect amount in the detected joining shape; and a position measurement section 2 for measuring an azimuth based on the corrected magnetism quantity.

TECHNICAL FIELD

This invention relates to a portable terminal device having a function of routing assistance of a human being, an automobile, etc., using a position measurement system.

BACKGROUND ART

In recent years, a pedestrian navigation system using GPS (global positioning system) has been developed. This pedestrian navigation system searches for a route to the destination based on the current position of the pedestrian and map information and displays the found route on a display section (for example, refer to patent document 1). Nowadays, a portable terminal device such as a portable telephone or a PDA installing the navigation system is provided for making it possible to give routing assistance to a pedestrian while conducting telephone conversation or communications.

By the way, a portable telephone provided with a display section such as a liquid crystal display and a key operation section on separate cases so that the terminal cases can be folded with one shaft as the center is provided. In the foldable portable telephone, a microphone and a loudspeaker as magnetism generation sections are provided on separate cases and a magnetism detection section is provided on either of the terminal cases.Patent document 1: JP-A-2001-204062

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, when the portable telephone is folded and is opened, the position and the orientation of the magnetism generation section relative to the magnetism detection section are changed, the magnitude of a magnetic field produced by the magnetism generation section relative to the magnetism detection section is changed, as a result, a position measurement value of the GPS becomes inaccurate.

The invention is embodied for solving the problems in the related art as described above and it is an object of the invention to provide a portable terminal device capable of always providing a precise azimuth if the distance or the direction from a magnetism generation section of a loudspeaker, etc., to a magnetism detector changes as cases are opened/closed or are rotated.

Means for Solving the Problems

A portable terminal device of the invention is a portable terminal device in which at least two cases can be joined with a plurality of shapes different in relative apart state, and includes a magnetism detection section which is provided in at least one of the plurality of cases and detects a magnetism quantity; a storage section which stores an effect amount produced by magnetism from a magnetism generation source of the portable terminal device in the magnetism quantity detected by the magnetism detection section for each of a plurality of joint shapes of the portable terminal device; a case shape detection section which detects the joint shape of the portable terminal device; a data processing section which corrects the magnetism quantity detected by the magnetism detection section based on the effect amount stored in the storage section in the joint shape detected by the case shape detection section; and a measurement section which measures an azimuth based on the magnetism quantity corrected by the data processing section.

According to the configuration, the effect of magnetism produced from various electronic machines and electronic circuits contained in the portable terminal device on the magnetism quantity detected by the magnetism detection section (magnetic sensor) is previously stored as geomagnetism correction data for each joint state of a plurality of cases included in the portable terminal device and when the geomagnetism quantity is calculated, the geomagnetism correction data is referenced and the magnetism quantity detected by the magnetism detection section is corrected, whereby the geomagnetism quantity can be precisely measured for each joint state of a plurality of cases and consequently the azimuth in which the portable terminal device is oriented can be measured precisely.

Also, in the portable terminal device of the invention, the data processing section stores the effect amount calculated based on the magnetism quantity detected by the magnetism detection section in the storage section in association with the joint shape of the portable terminal device detected by the case shape detection section when the portable terminal device rotates in a horizontal direction.

According to the configuration, if there are various joint shapes in various portable terminal devices, the effect of magnetism produced from various electronic machines and electronic circuits contained in the portable terminal device on the magnetism quantity detected by the magnetism detection section can be registered as geomagnetism correction data for each of the joint shapes, and the geomagnetism quantity can be precisely measured for each of various joint shapes.

Advantages of the Invention

According to the portable terminal device of the invention, a precise azimuth can always be provided if the distance or the direction from the magnetism generation section of a loudspeaker, etc., to the magnetism detector changes as the terminal cases are opened/closed or are rotated.

DESCRIPTION OF REFERENCE NUMERALS

BEST MODE FOR CARRYING OUT THE INVENTION

A portable terminal device of an embodiment of the invention will be discussed with the accompanying drawings.

FIG. 1shows the portable terminal device of the embodiment of the invention.

InFIG. 1, a portable terminal device101has a wireless section1, a position measurement section2, a data processing section3, a case shape detection section4, a display section5, a voice input/output section6, a key input section7, a magnetism detection section8, a storage section9, open/closed detection sections10of terminal cases, and rotation detection sections11of terminal cases.

The wireless section1transmits and receives various pieces of information of audio, voice, an image, etc., to and from an external wireless terminal in a wireless manner

The position measurement section2measures the position of the portable terminal device101according a method of using the radio wave propagation time difference between each of base stations of portable telephones of the GPS, OTDOA (Observed Time Difference Of Arrival), EOTD (Enhanced Observed Time Difference), etc., and the terminal.

The data processing section3controls the whole operation of the portable terminal device101and is implemented mainly as a processor operating according to a predetermined program. In the invention, particularly the data processing section3calculates a difference from geomagnetism information for each selected different case shape based on geomagnetism information corresponding to a predetermined case shape detected by the case shape detection section4and previously stores the difference in a geomagnetism correction data table of the storage section9as geomagnetism correction data. The data processing section3can correct magnetism information for each case shape detected by the magnetism detection section8by referencing the geomagnetism correction data table.

The case shape detection section4detects the shapes of a plurality of (in the embodiment, two) terminal cases joined so that the whole shape can be changed, and detects the shape of the terminal case based on open/closed information obtained from either of the open/closed detection sections10and rotation information obtained from either of the rotation detection sections11.

The terminal case shapes are as shown inFIGS. 2(a) to2(f), for example. InFIG. 2(a), a terminal case22having a display section (not shown) and a terminal case21having a key section (not shown) are joined so that they can be opened and closed with one shaft; when they are closed, a sub liquid crystal display section23faces the outside.

InFIG. 2(b), a terminal case24and a terminal case25are joined so that the terminal cases can be opened and closed and can be rotated with two shafts; when the terminal cases are closed, a main liquid crystal display section26faces the outside.

InFIG. 2(c), a terminal case29having a key section27and a voice input section (microphone)28and a terminal case32having a main liquid crystal display section30and a voice output section (loudspeaker)31are joined so that the terminal cases can be opened and closed with one shaft. InFIG. 2(c), further, in a state in which the terminal case32is opened, it can be rotated 90 degrees within the same plane with another shaft as the center.

FIG. 2(d) shows the portable terminal device101such as a general open/closed type portable telephone; a terminal case35having a key section33and a voice input section34and a terminal case38having a main liquid crystal display section36and a voice output section37are joined so that the terminal cases can be opened and closed with one shaft.

Further, inFIG. 2(e), a terminal case44having a main liquid crystal display section42and a voice output section43can be opened and closed with one shaft relative to a terminal case41having a key section39and a voice input section40, and in the open state, the terminal case44can be rotated 90 degrees in an opposite direction to that shown inFIG. 2(c).

InFIG. 2(f), a terminal case50having a main liquid crystal display section48and a voice output section49is slid relative to a terminal case47having a key section45and a voice input section46as the terminal cases can be opened and closed with one shaft. The open/closed state and the rotation state of the terminal cases is detected by the open/closed detection section10and the rotation detection section11and is input to the case shape detection section4. The case shape detection section4detects the case shape (form) changing as the case is open/closed or is rotated, and outputs the case shape to the data processing section3.

InFIG. 1, the display section5corresponds to the main liquid crystal display section23,26,30,36,42,48inFIG. 2, and the voice input/output section6corresponds to the voice input section28,34,40,46and the voice output section31,37,43,49inFIG. 2. The key input section7inFIG. 1corresponds to the key section27,33,39,45inFIG. 2.

FIG. 3illustrates an open/closed detection section of the two terminal cases21and22, for example, inFIG. 2(a). In the open/closed detection section, the terminal case22opened and closed with a hinge part51as the center is formed with a convex part52and the terminal case21is formed with a concave part53into which the convex part52is fitted. The relationship between the convex part52and the concave part53may be opposite.

The concave part53is provided with a switch element54. In the open/closed detection section, when the terminal cases21and22are closed, the convex part52causes the switch element54in the concave part53to operate; on the other hand, when the terminal cases are opened, the operation of the switch element54is released. As the switch element54is operated and the operation of the switch element54is released, the open state and the closed state of the terminal cases21and22can be detected.

FIG. 4shows that the terminal case22is provided with a magnet55and the terminal case21is provided with a magnetism detection section56such as a hall device in the part corresponding to the magnet55as an open/closed detection mechanism. In the open/closed detection mechanism, when the terminal cases21and22are closed, the magnetism detection section56outputs a detection signal upon reception of magnetism of the magnet55; on the other hand, when the terminal cases are opened, the magnetism detection section56stops outputting the detection signal. The open state and the closed state of the terminal cases21and22can be detected according to whether or not the detection signal is output. The positions of the magnet55and the magnetism detection section56may be opposite.

Such an open/closed detection section can also be applied to the terminal cases24and25, the terminal cases29and32, the terminal cases35and38, the terminal cases41and44, and the terminal cases47and50. Although not shown, mechanical or magnetic detection units similar to that described above is also adopted for the rotation detection section, whereby rotation detection of the terminal cases can be easily accomplished.

The portable terminal device with the terminal cases opened and closed or rotated with one shaft or two or more shafts has one or more offset values while the number of offset values of magnetism detection section8in the terminal case not adopting an open/closed or rotation structure is one. Assuming that the magnetism detection section8attached to a portable telephone has two azimuth detection elements8aand8bplaced at the right angle within the same plane as shown inFIG. 5, if the output values are measured about all azimuths, they become like a sinusoidal form as shown inFIG. 6. However, the phases of outputs of X and Y axes differ (generally a shift of 90 degrees). At this time, letting the outputs of the azimuth detection elements8aand8bbe Hx and Hy, azimuth angle θ=arc tan (Hy/Hx), and the azimuth angle θ and the azimuth output values can be represented on X, Y coordinates as shown inFIG. 7.

Next, the operation of the portable terminal device101shown inFIG. 1is as follows:

To begin with, to use the portable terminal device101for man navigation for a pedestrian, geomagnetism offset information is set in the geomagnetism correction data table of the storage section9as geomagnetism correction data. The geomagnetism correction data corrects the effect of a magnetic field of the magnetism generation section of the loudspeaker, the microphone, etc., of the terminal case as the two terminal cases are opened/closed or are rotated on the magnetism detection section8.

FIG. 8is a schematic representation to show the effect of the magnetic field of the magnetism generation section on the magnetism detection section8, andFIG. 9is a flowchart to show a setting procedure of the geomagnetism correction data to remove the effect.FIG. 8shows the effect of giving a magnetic field different from geomagnetism by the loudspeaker or the microphone on the magnetism detection section8when the case shape changes fromFIG. 2(d) toFIG. 2(a) orFIG. 2(b), for example, as the two terminal cases are opened/closed or are rotated.

That is, as the terminal cases are opened/closed or are rotated, the output level of the magnetism detection section8drifts and, for example, the center coordinates of the outputs of the azimuth detection elements8aand8bon XY coordinates shift from P0(x0, y0) inFIG. 2(d) to P1(x1, y1) inFIG. 2(a) or P2(x2, y2) inFIG. 2(b). InFIG. 8, circles61,62, and63are loci drawn based on the effect of geomagnetism of the earth according to the azimuth in which the portable terminal device101should be oriented about the center coordinates P0, P1, and P2.

From the information of the optimum center coordinates P0(x0, y0) to Pn (xn, yn) corresponding to the case shape thus obtained, the shifts (differences) from the coordinates P1(x1, y1) to Pn (xn, yn) with the center coordinates P0(x0, y0) as the center are found. The differences are previously stored in the geomagnetism correction data table9at the product shipment time, etc.

When the case shape changes at the actual use time of the portable terminal device101, the geomagnetism correction data table in the storage section9is referenced and the differences are used as geomagnetism correction data.

Accordingly, the shift from other center coordinates P1(x1, y1), P2(x2, y2) . . . , namely, the azimuth detection output shift can be corrected with the center coordinates P0(x0, y0) as the reference and consequently, precise azimuth detection independent of change in the case shape can be made.

Next, the setting procedure of the geomagnetism correction data table in the storage section9will be discussed with reference toFIG. 9.

First, in one case shape used as the reference (for example,FIG. 2(d)), the portable terminal device101, namely, the magnetism detection section8is rotated one revolution or more within a flat plane (calibration operation) (step S1).

The data processing section3calculates the center coordinates P0(x0, y0) and the radius of circle, for example, as shown inFIG. 6from output of the magnetism detection section8and stores them in the geomagnetism correction data table (step S2). Accordingly, the reference azimuth for geomagnetism in the case shape inFIG. 2(d) is set.

Subsequently, the case shape is set to each state as the terminal cases are opened/closed or are rotated as shown inFIG. 2(a), (b), (c), (e), (f) and the portable terminal device101is rotated within a flat plane in a similar manner to that described above. From each magnetism detection section8, output corresponding to each azimuth is obtained and the data processing section3calculates the center coordinates P2(x2, y2), P3(x3, y3) . . . Pn (xn, yn) of circles as shown inFIG. 8(step S3).

Further, geomagnetism correction data is found from the differences from the azimuth output values in the coordinates P1(x1, y1), P2(x2, y2) . . . Pn (xn, yn) corresponding to the case shapes with the azimuth output value in the center coordinate P0(x0, y0) as the reference, and the correction values are stored in the geomagnetism correction data table in the storage section9in correspondence with the coordinates P1(x1, y1) to Pn (xn, yn) (step S4).

Using the stored geomagnetism correction data, as described above, newly measured (detected) azimuth data is automatically corrected without troubling the user, whereby precise geomagnetism corresponding to each case shape can be measured.

Therefore, in the invention, if the magnetism detection section8receives the effect of the magnetic field from the magnetism generation section of the loudspeaker, the microphone, etc., using the geomagnetism correction data corresponding to the case shape detected (measured) by the case shape detection section4, the effect of geomagnetism in the case shape can be corrected and consequently man navigation, etc., based on correct azimuth detection can be realized.

The user of the portable terminal device101rotates the portable terminal device101within a flat plane for each case shape as the calibration operation, whereby geomagnetism correction data is found in a similar manner to that described above and can also be stored in the geomagnetism correction data table for use.

Also in this case, using the geomagnetism correction data corresponding to the case shape detected by the case shape detection section4, the effect of geomagnetism in the case shape can be corrected and consequently man navigation, etc., based on correct azimuth detection can be realized.

INDUSTRIAL APPLICABILITY

The portable terminal device of the invention has the advantage that if the distance or the direction from the magnetism generation section of the loudspeaker, etc., to the magnetism detector changes as the terminal cases are opened/closed or are rotated, a precise azimuth can always be obtained, and is useful in the field of a portable terminal device, etc., having the function of routing assistance of a human being, an automobile, etc., in the precise direction using the position measurement system.

While the invention has been described in detail with reference to the specific embodiments, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and the scope of the invention.

This application is based on Japanese Patent Application (No. 2005-019929) filed on Jan. 27, 2005, which is incorporated herein by reference.