Position detecting device

Abstract

The present invention relates to a position detecting device and, more specifically, limits a magnet, a magnetic field detection means for outputting a value of a magnetic field corresponding to movement of the magnet, and a position detecting device capable of detecting the position of the magnet by processing the magnetic field output from the magnetic field detection means. The position detecting device according to the present invention comprises the magnet, the magnetic field detection means, and a signal processing means.

Description

position detection device

[0001] The present invention relates to a position detection device, and more particularly, to a magnetic field detection means for outputting a value of a magnetic field corresponding to the movement of a magnet, and a position detection device capable of detecting the position of the magnet by processing the magnetic field output from the magnetic field detection means.

[0002] Due to the miniaturization of digital cameras, Hall elements and magnets are increasingly used to focus the lens. The magnet is typically attached to the lens, and the Hall element is fixed along the lens path. As the lens moves and changes position, the output voltage of the Hall element, which acts as a magnetic sensor, changes. The lens position is detected by detecting this change in output voltage.

[0003] Japanese Patent Application Laid-Open No. H05-323173 proposes a function for detecting whether the lens is at the reference position based on an output from the photointerrupter, in which an image capturing device is provided with a shading plate that moves integrally with the lens, and a photointerrupter is installed at the reference position of the lens.

[0004] In addition, Japanese Patent Application Laid-Open No. 2001-289605 proposes a technology for detecting the position of a moving body configured to move in a predetermined direction in a position detection device, which is configured to detect the position in a predetermined direction of a moving body, the position detection device having at least one magnet and one Hall element, wherein each magnet is integrally installed on the moving body with its magnetic poles (S pole and N pole) oriented in a direction according to the moving direction of the moving body, and the Hall element is fixed to face the magnet at a predetermined interval, and the position of the moving body is detected by utilizing the output of the Hall element that changes according to the position of the magnet in the predetermined direction.

[0005] Conventional technologies have the disadvantage of being difficult to achieve in terms of technical economy as well as miniaturization of position detection devices due to their complex configuration and processing process.

[0006] The technical problem to be solved by the present invention relates to a position detection device, and more particularly, to providing a position detection device capable of detecting the position of the magnet by processing a magnetic field output from a magnet, a magnetic field detection means for outputting a value of a magnetic field corresponding to the movement of the magnet, and a magnetic field output from the magnetic field detection means.

[0007] A position detection device according to the present invention for achieving the above technical task includes a magnet, a magnetic field detection means, and a signal processing means.

[0008] The magnetic field detection means installs at least two Hall sensors parallel to the direction in which the magnet moves, and each outputs a change in the magnetic field value according to the movement of the magnet. The signal processing means extracts a first magnetic field value, which is a magnetic field value of a central portion of a space in which the magnet moves, and a second magnetic field value, which is a difference magnetic field value between the first magnetic field value and the magnetic field values ​​of both edges of the space in which the magnet moves, using each magnetic field value received from the magnetic field detection means, and compares the first magnetic field value and the second magnetic field value with two preset comparison magnetic field areas, and logically combines the comparison results to detect the position of the magnet.

[0009] The position detection device according to the present invention as described above has the advantage of being capable of detecting the position of the magnet by processing a magnet, a magnetic field detection means for outputting a value of a magnetic field corresponding to the movement of the magnet, and a magnetic field output from the magnetic field detection means, and being suitable for miniaturization of a chip.

[0010] Figure 1 shows one embodiment of a position detection device according to the present invention.

[0011] Figure 2 shows one embodiment of a position detection device according to the present invention.

[0012] Figure 3 is another embodiment of a position detection device according to the present invention.

[0013] Figure 4 shows examples of signals used in a position detection device according to the present invention.

[0014] Hereinafter, the present invention will be described in detail by describing preferred embodiments thereof with reference to the attached drawings. The same reference numerals in each drawing represent the same components.

[0015] Figure 1 shows one embodiment of a position detection device according to the present invention.

[0016] Referring to FIG. 1, a position detection device (100) according to the present invention includes a magnet (110), a magnetic field detection means (120), and a signal processing means (130).

[0017] According to an embodiment, the magnet (110) can be attached to a lens (not shown) of a digital camera.

[0018] The magnetic field detection means (120) installs at least two Hall sensors (not shown) parallel to the direction in which the magnet (110) moves, and outputs a change value of the magnetic field according to the moving magnet (110).

[0019] The signal processing means (130) includes a first magnetic field value generation device (131), a second magnetic field value generation device (132), a comparison means (133), a logic circuit (134), and a storage means (135), and receives magnetic field values ​​measured by a plurality of Hall sensors included in the magnetic field detection means (120).

[0020] The first magnetic field value generator (131) extracts the first magnetic field value (Bc), which is the magnetic field value of the center of the space in which the magnet (110) moves, using the value of the received magnetic field.

[0021] The second magnetic field value generator (132) uses the received magnetic field value to extract the second magnetic field value (Bd), which is the difference value between the magnetic fields at both edges of the moving space while the magnet (110) moves.

[0022] The comparison means (133) compares the first magnetic field value (Bc) and the second magnetic field value (Bd) with two preset comparison magnetic field areas (Area1 & Area2).

[0023] For convenience, the location of a certain length through which the magnet (110) moves is divided into multiple zones, and the location of the magnet (110) is determined based on which zone it is located, rather than the exact location of the magnet (110). For convenience of explanation, the location of movement is divided into four zones (POS1 to POS4).

[0024] The first comparative magnetic field area (Area1) has a magnetic field value between the first-first comparative magnetic field value (Bcrp) and the first-second comparative magnetic field value (Bcop). Here, the first-first comparative magnetic field value (Bcrp) is smaller than the first-second comparative magnetic field value (Bcop).

[0025] The second comparative magnetic field area (Area2) has a magnetic field value between the second-first comparative magnetic field value (Bdrp) and the second-second comparative magnetic field value (Bdop). Here, the second-first comparative magnetic field value (Bdrp) is smaller than the second-second comparative magnetic field value (Bdop).

[0026] In the following, the explanation is given assuming that the 1-1 comparative magnetic field value (Bcrp) is greater than the 2-2 comparative magnetic field value (Bdop).

[0027] The comparison means (133) uses the first comparison means (not shown) to divide the first magnetic field value (Bc) into a section (first section, P1) in which the first magnetic field value (Bc) is smaller than the 1-1 comparative magnetic field value (Bcrp) and a section (second section, P2) in which the first magnetic field value (Bc) is larger than the 1-2 comparative magnetic field value (Bcop). In addition, the second comparison means (not shown) uses the second comparison means to divide the second magnetic field value (Bd) into a section (third section, P3) in which the second magnetic field value (Bd) is smaller than the 2-1 comparative magnetic field value (Bdrp) and a section (fourth section, P4) in which the second magnetic field value (Bd) is larger than the 2-2 comparative magnetic field value (Bdop).

[0028] The logic circuit (134) logically combines the fourth section information (section 1 to section 4) generated by the comparison means (133) to determine in which of the four sections (POS1 to POS4) the magnet (110) is located.

[0029] The storage means (135) stores the 1-1 comparative magnetic field value (Bcrp), the 1-2 comparative magnetic field value (Bcop), the 2-1 comparative magnetic field value (Bdrp), and the 2-2 comparative magnetic field value (Bdop). The values ​​stored in the storage means (135) can be set by the user according to the magnet (110), the magnetic field detection means (120), and the device installed in the magnet (110), and the more optimal values ​​are set and stored by reflecting the results of trials and errors, the more the performance of the position detection device (100) according to the present invention will be optimized.

[0030] Below, implementation examples of position detection devices according to the present invention and their operating characteristics are described.

[0031] Figure 2 shows one embodiment of a position detection device according to the present invention.

[0032] Referring to FIG. 2, a position detection device (100) according to the present invention includes a magnet (110), a magnetic field detection means (120), and a signal processing means (130).

[0033] The magnet (110) reciprocates along the dotted arrow between preset sections (Le, Re). When the left end of the preset section is Le, the right end is assumed to be Re.

[0034] The magnetic field detection means (120) includes two Hall sensors (1201, 1202). The two Hall sensors (1201, 1202) are installed in series in a direction parallel to the path along which the magnet (110) moves, close to the path along which the magnet (110) moves, and detect a magnetic field value that changes when the magnet (110) moves.

[0035] The signal processing means (130) includes a first magnetic field value generation device (131), a second magnetic field value generation device (132), a comparison means (133), a logic circuit (134), and a storage means (135), and receives magnetic field values ​​measured by a plurality of Hall sensors included in the magnetic field detection means (120).

[0036] The first magnetic field value generator (131) extracts the first magnetic field value (Bc), which is the magnetic field value of the center of the space in which the magnet (110) moves, using the magnetic field values ​​received from the two Hall sensors (1201, 1202). The first magnetic field value (Bc) has the largest value when the magnet (110) is located at the center of the space in which the magnet (110) moves, and will decrease as it moves away from the center of the space in which the magnet (110) moves to either side.

[0037] The second magnetic field value generator (132) extracts the second magnetic field value (Bd), which is the difference between the magnetic field value of the center (Cen) and the magnetic field values ​​of the two edges (Le, Re) of the moving space while the magnet (110) moves, by using the values ​​of the magnetic field received from the two Hall sensors (1201, 1202). The second magnetic field value (Bd) will be the difference (Bc - BLe) between the magnetic field value measured at the left edge (Le) from the left side (Le) of the moving path and the magnetic field value measured at the center (Cen) at the same time, and from the center (Cen) to the right edge (Re) will be the difference (BRe - Bc) between the magnetic field value measured at the right edge (Re) of the right side and the magnetic field value measured at the center (Cen) at the same time.

[0038] The changes in the first magnetic field value (Bc) and the second magnetic field value (Bd) according to the position of the magnet (110) will be described later.

[0039] The comparison means (133) includes two comparison means (1331, 1332).

[0040] The first comparison means (1331) compares the first magnetic field value (Bc) with the 1-1 comparative magnetic field value (Bcrp) and the 1-2 comparative magnetic field value (Bcop), and divides the first magnetic field value (Bc) into a section (1st section, P1) in which the first magnetic field value (Bc) is smaller than the 1-1 comparative magnetic field value (Bcrp) and a section (2nd section, P2) in which the first magnetic field value (Bc) is larger than the 1-2 comparative magnetic field value (Bcop).

[0041] The second comparison means (1332) compares the second magnetic field value (Bd) with the second-1 comparative magnetic field value (Bdrp) and the second-2 comparative magnetic field value (Bdop), respectively, and divides the second magnetic field value (Bd) into a section (third section, P3) in which the second magnetic field value (Bd) is smaller than the second-1 comparative magnetic field value (Bdrp) and a section (fourth section, P4) in which the second magnetic field value (Bd) is larger than the second-2 comparative magnetic field value (Bdop).

[0042] When the comparison result of the first comparison means (1331) and the second comparison means (1332) determines that the position of the magnet (110) is located in the corresponding section, the corresponding section has a logic high value. Here, the meaning of the corresponding section having a logic high value means that the signal (P1 to P4) indicating the corresponding section has a logic high value.

[0043] The logic circuit (134) includes four logical product means (1341 to 1344) that logically combine four sections of information (first section to fourth section) generated from the comparison means (133).

[0044] The first logical product means (1341) has a logical high value only when the first section (P1) and the third section (P3) are logical high. The second logical product means (1342) has a logical high value only when the second section (P2) and the third section (P3) are logical high. The third logical product means (1343) has a logical high value only when the second section (P2) and the fourth section (P4) are logical high. The fourth logical product means (1344) has a logical high value only when the first section (P1) and the fourth section (P4) are logical high. When the magnetic field value according to the position of the magnet (110) is processed, only one of the four logical product means will have a logical high value and the remaining three will have logical low values.

[0045] Since the four logical product means (1341 to 1344) correspond to the four zones (POS1 to POS4), respectively, the position of the moving magnet (110) at a specific time can be determined to be located in one of the four zones (POS1 to POS4) corresponding to the four logical product means (1341 to 1344).

[0046] Since Fig. 2 uses two Hall sensors (1201, 1202), a first magnetic field value generation device (131) that separately calculates the magnetic field value of the center (Cen) when the magnet (110) is moving is used. As described above, the first magnetic field value generation device (131) calculates the magnetic field value detected by the two Hall sensors (1201, 1202) to separately calculate the magnetic field value of the center (Cen). However, the circuit configuration required for this is complex and therefore the area it occupies on the semiconductor chip is considerable, which may have a negative effect on the miniaturization of the chip.

[0047] To improve this, an embodiment that does not use the first magnetic field value generator (131) by using three Hall sensors is described below.

[0048] Figure 3 is another embodiment of a position detection device according to the present invention.

[0049] Referring to FIG. 3, the position detection device (100) according to the present invention is the same as the position detection device (100) illustrated in FIG. 2 in that it includes a magnet (110), a magnetic field detection means (120), and a signal processing means (130).

[0050] However, there is a difference in that one more Hall sensor is added as a magnetic field detection means (120) and the first magnetic field value generation device (131) is not used in the signal processing means (130).

[0051] Other than that, the embodiment illustrated in FIG. 3 is the same as the embodiment illustrated in FIG. 2, so only the different parts will be described below, and the same parts will be replaced with the description of FIG. 2.

[0052] The magnetic field detection means (120) includes three Hall sensors (1201 to 1203). When the three Hall sensors (1201 to 1203) are arranged in series, the first Hall sensor (1201) is installed near the left end (Le) of the movement path, the third Hall sensor (1203) is installed near the right end (Re), and the second Hall sensor (1202) is arranged at the center (Cen) of the movement path of the magnet (110).

[0053] By having the second Hall sensor (1202) directly measure the magnetic field value of the central portion (Cen) on the movement path of the magnet (110), the first magnetic field value generation device (131) that calculates the magnetic field value of the central portion (Cen) on the movement path of the magnet (110) can be omitted.

[0054] The second magnetic field value generator (132) extracts the second magnetic field value (Bd), which is the difference between the magnetic field values ​​of the two edges (Le, Re) of the moving space and the magnetic field value of the center (Cen) while the magnet (110) moves, by using the values ​​of the magnetic field received from the two Hall sensors (1201, 1203). The second magnetic field value (Bd) will be the difference (Bc - BLe) between the magnetic field value measured at the left edge (Le) and the magnetic field value measured at the center (Cen) at the same time from the left (Le) to the center (Cen) of the moving path, and will be the difference (BRe - Bc) between the magnetic field value measured at the right edge (Re) of the right side and the magnetic field value measured at the center (Cen) at the same time from the center (Cen) to the right edge (Re).

[0055] As described above, the description of the parts where the configuration and connection relationship of Fig. 3 are the same as those of Fig. 2 is omitted.

[0056] Below, the operation of the position detection device according to the present invention is described based on the magnetic field value waveform according to time and position.

[0057] Figure 4 shows examples of signals used in a position detection device according to the present invention.

[0058] Referring to Fig. 4, it is assumed that the magnetic field value is -12 to 12, and the length of the movement path of the magnet (110) is approximately 10 mm (millimeters).

[0059] FIG. 4 can be divided into upper and lower drawings, and the upper drawing shows the waveforms of the first magnetic field value (Bc) and the second magnetic field value (Bd) and four comparative magnetic field values, namely, the 1-1 comparative magnetic field value (Bcrp), the 1-2 comparative magnetic field value (Bcop), the 2-1 comparative magnetic field value (Bdrp), and the 2-2 comparative magnetic field value (Bdop), respectively.

[0060] The lower drawings show the first section (P1) and the second section (P2) distinguished by comparing the width of the first-first comparative magnetic field value (Bcrp) having a relatively small value and the first-second comparative magnetic field value (Bcop) having a relatively large value with the first magnetic field value (Bc), and the second section (P3) and the fourth section (P4) distinguished by comparing the width of the second-first comparative magnetic field value (Bdrp) having a relatively small value and the second-second comparative magnetic field value (Bdop) having a relatively large value with the second magnetic field value (Bd).

[0061] The position of the magnet (110) in a certain section (Noise) of the direction change in which the magnet (110) moves from the left to the right end and then moves back to the left can be set to the position immediately before the magnet (110) enters the certain section (Noise).

[0062] The present invention relates to a position detection device, which, when mounted on a digital camera, can detect a change in position due to movement of a lens. In this way, the device can be applied to all industries that require the position of an object to be mounted to be identified.

Claims

1. Magnet; A magnetic field detection means for installing at least two Hall sensors parallel to the direction in which the magnet moves, each of which outputs a change in the magnetic field value according to the movement of the magnet; and A signal processing device that extracts a first magnetic field value, which is a magnetic field value of the center of the space in which the magnet moves, and a second magnetic field value, which is a difference magnetic field value between the first magnetic field value and the magnetic field values ​​of both edges of the space in which the magnet moves, by using each magnetic field value received from the magnetic field detection means, and compares the first magnetic field value and the second magnetic field value with two preset comparison magnetic field areas, and logically combines the comparison results to detect the position of the magnet; A position detection device including:

2. In paragraph 1, the signal processing means, A first magnetic field value generation device that extracts the first magnetic field value using the received magnetic field value; A second magnetic field value generation device that extracts the second magnetic field value using the value of the received magnetic field; A comparison means for comparing the first magnetic field value and the second magnetic field value with the two comparison magnetic field areas and outputting the comparison results as the first to fourth sections; and A position detection means including a logic circuit that determines in which zone of the magnet's movement path the magnet is located by logically combining the first to fourth section information output from the comparison means.

3. In the second paragraph, the comparison magnetic field region includes a first comparison magnetic field region and a second comparison magnetic field region, The first comparative magnetic field region has a magnetic field value between the first-first comparative magnetic field value and the first-second comparative magnetic field value, and the first-first comparative magnetic field value is smaller than the first-second comparative magnetic field value. The second comparative magnetic field region has a magnetic field value between the second-first comparative magnetic field value and the second-second comparative magnetic field value, and the second-first comparative magnetic field value has a smaller magnetic field value than the second-second comparative magnetic field value. A position detection device in which the above 1-1 comparative magnetic field value is greater than the above 2-2 comparative magnetic field value.

4. In the third paragraph, the comparison means includes a first comparison means and a second comparison means, The first comparison means divides the section in which the first magnetic field value is smaller than the 1-1 comparative magnetic field value into the first section, and divides the section in which the first magnetic field value is larger than the 1-2 comparative magnetic field value into the second section. The second comparison means divides the section in which the second magnetic field value is smaller than the 2-1 comparative magnetic field value into the third section, and divides the section in which the second magnetic field value is larger than the 2-2 comparative magnetic field value into the fourth section. A position detection device in which, when it is determined as a result of comparison between the first comparison means and the second comparison means that the position of the magnet is located in the corresponding section, the corresponding section has a logic high value.

5. In paragraph 4, the logic circuit, A first logical product means having a logical high value when the first section and the third section are logical high; A second logical product means having a logical high value when the second section and the third section are logical high; A third logical product means having a logical high value when the second section and the fourth section are logical high; and A position detection device including a fourth logical product means having a logical high value when the first section and the fourth section are logical high.

6. In paragraph 2, A position detection device further comprising a storage means for storing the first-first comparative magnetic field value, the first-second comparative magnetic field value, the second-first comparative magnetic field value, and the second-second comparative magnetic field value.

7. In paragraph 1, the magnetic field detection means, A second Hall sensor installed in the central portion of the movement path of the magnet and outputting the first magnetic field value; A first Hall sensor installed on the left side of the second Hall sensor; and A third hall sensor installed on the right side of the second hall sensor; A position detection device including:

8. In paragraph 7, the signal processing means, A second magnetic field value generation device that extracts the second magnetic field value using the magnetic field values ​​received from the first Hall sensor and the third Hall sensor; A comparison means for comparing the first magnetic field value and the second magnetic field value with the two comparison magnetic field areas and outputting the comparison results as the first to fourth sections; and A position detection device including a logic circuit that determines in which zone of the magnet's movement path the magnet is located by logically combining the first to fourth section information output from the comparison means.

Images