Encoder and information processing method

Abstract

Provided is an encoder capable of suppressing a decrease in detection accuracy. The encoder includes a moving plate, a light irradiation unit that irradiates a code pattern with light, and a light receiving unit. The code pattern is composed of light-guiding sections and non-light-guiding sections. An array of the code pattern is obtained by inserting an error correction code for correcting errors in a position information data string in which positions can be determined. The light receiving unit includes a position-detecting light receiving element that reads the position array of the code pattern, and a position-correcting light receiving element that outputs information for correcting errors.

Description

Technical Field

[0001] This disclosure relates to an encoder. More particularly, it relates to an encoder for detecting the rotational position of a rotating body or the movement position of a linearly moving body. Background Technology

[0002] Previously, an encoder for detecting the rotation of a motor's rotating shaft was known. For example, Patent Document 1 discloses an encoder having: a pattern along a measurement direction; a light source that emits light toward the pattern; and a plurality of light-receiving elements configured to be arranged along the measurement direction and to receive light emitted from the light source and transmitted through or reflected by the pattern.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-118486 Summary of the Invention

[0006] However, in the encoder described in Patent Document 1, when dust or the like adheres to the pattern, this dust or the like can sometimes prevent light from the light source from passing through or be reflected, resulting in false detections. In this case, the encoder cannot recognize the false detections, leading to a decrease in detection accuracy.

[0007] In addition, the following problem exists: even if the encoder recognizes a false detection, it is difficult to correct the error and cannot detect the rotational position.

[0008] This disclosure was made to solve the above-mentioned problems, and its purpose is to provide an encoder that can detect and correct errors even when false detections occur.

[0009] The encoder disclosed herein includes a moving plate, a light irradiation section, and a light receiving section. The moving plate has a code pattern. The code pattern consists of a light guiding section and a non-light guiding section. The array of code patterns is an array obtained by inserting error correction codes for correcting errors into a position information data string that can determine the position. The light irradiation section irradiates light onto the code pattern. The light receiving section includes a light receiving element for position detection and a light receiving element for position correction. The light receiving element for position detection reads the position array of the code pattern. The light receiving element for position correction outputs information for correcting errors.

[0010] The encoder according to this disclosure can identify and correct position detection errors caused by foreign objects and suppress the decrease in detection accuracy. Attached Figure Description

[0011] Figure 1This is a schematic diagram showing the structure of the optical encoder according to embodiments 1 to 5 of this disclosure.

[0012] Figure 2 This is a diagram showing the main structural components of the optical encoder according to Embodiment 1.

[0013] Figure 3 This is a flowchart illustrating the process of determining and correcting error locations in the signal of the optical encoder involved in Embodiment 1.

[0014] Figure 4 This is a diagram illustrating the operating principle of the optical encoder according to Embodiment 1.

[0015] Figure 5A This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 1.

[0016] Figure 5B This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 1.

[0017] Figure 6A This is a diagram illustrating the error correction method of the optical encoder according to Embodiment 1.

[0018] Figure 6B This is a diagram illustrating the error correction method of the optical encoder according to Embodiment 1.

[0019] Figure 7 This is a diagram illustrating the operating principle of the optical encoder according to Embodiment 2.

[0020] Figure 8A This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 2.

[0021] Figure 8B This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 2.

[0022] Figure 9 This is a diagram illustrating the effect of error detection when different types of foreign objects cover two consecutive parts of the code pattern in the optical encoder according to Embodiment 2.

[0023] Figure 10 This is a diagram illustrating the operating principle of the optical encoder according to Embodiment 3.

[0024] Figure 11AThis is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 3.

[0025] Figure 11B This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 3.

[0026] Figure 12 This is a diagram illustrating the operating principle of the optical encoder according to Embodiment 4.

[0027] Figure 13A This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 4.

[0028] Figure 13B This is a diagram showing the effect of detecting erroneous parts when a foreign object covers a portion of the code pattern in the optical encoder according to Embodiment 4.

[0029] Figure 14A This is a schematic diagram illustrating an example of the optical encoder according to Embodiment 6.

[0030] Figure 14B This is a perspective view showing the moving body of the optical encoder according to Embodiment 6. Detailed Implementation

[0031] The following describes embodiments of this disclosure. Furthermore, each embodiment described below illustrates a specific example of this disclosure. Therefore, the numerical values, constituent elements, arrangement and connection methods of constituent elements, and processes and their order shown in the following embodiments are examples and are not intended to limit this disclosure. Therefore, constituent elements in the following embodiments that represent the highest-level concept of this disclosure but are not described in the independent claims are described as arbitrary constituent elements.

[0032] In addition, the figures are schematic diagrams and may not be strictly illustrative. Furthermore, in each figure, substantially identical structures are labeled with the same reference numerals, and repetitive descriptions are omitted or simplified.

[0033] Figure 1This is a schematic diagram showing the structure of the optical encoders 100, 200, 300, and 400 according to embodiments 1 to 5 of this disclosure. The optical encoders 100, 200, 300, and 400 include a rotating plate 1, a light irradiation section 3, a light receiving section 4, a determination section 8, and a correction section 9. The rotating plate 1 has, for example, a circular plate shape. Furthermore, the rotating plate 1 is mounted, for example, with the rotation axis SH of a rotating body 21 (such as a motor) coaxial with the central axis of the rotating plate 1, and the main surface of the rotating plate 1 perpendicular to the rotation axis SH. A code pattern 2 is provided on the main surface of the rotating plate 1 and is positioned opposite to the rotating body 21 when viewed from the rotating plate 1. The code pattern 2 has a circumferential shape centered on the rotation axis SH. The light irradiation section 3 and the light receiving section 4 are provided on the main surface of the fixing section 22, which serves as a substrate, and are facing the main surface of the fixing section 22. The determination section 8 and the correction section 9 are provided on the surface opposite to the main surface of the fixing section 22 where the light irradiation section 3 and the light receiving section 4 are provided. The light irradiation unit 3, for example, includes an LED (Light Emitting Diode). The light receiving unit 4, for example, includes a light receiving element. Light α emitted from the LED of the light irradiation unit 3 illuminates the code pattern 2, and the light receiving element of the light receiving unit 4 receives the light α reflected back by the code pattern 2. The light receiving unit 4, the determination unit 8, and the correction unit 9 are electrically connected. The determination unit 8, for example, includes electronic circuitry. The determination unit 8 processes the signal of the light α received by the light receiving element of the light receiving unit 4. Furthermore, the correction unit 9, for example, includes electronic circuitry. The correction unit 9 processes the signal from the determination unit 8.

[0034] (Implementation Method 1)

[0035] Figure 2 This is a diagram showing the main structural components of the optical encoder 100 in Embodiment 1. (Refer to...) Figure 1 and Figure 2 To illustrate the structure of the optical encoder 100. Figure 3 This diagram illustrates the processing technology for determining and correcting error locations in the signal of the optical encoder 100 according to Embodiment 1. (Refer to...) Figure 3 This section explains the processing technology up to the correction of errors in the optical encoder 100. Additionally, Figure 4 This diagram illustrates the operating principle of the optical encoder 100 according to Embodiment 1, namely, the encoding of the position information code 10 by inserting the error correction code 16 through Manchester encoding.

[0036] The optical encoder 100 includes a rotating plate 1, a light irradiation unit 3, a light receiving unit 4, a judgment unit 8, and a correction unit 9.

[0037] The rotating plate 1 is provided with a code pattern 2 that indicates the position information of the rotating plate 1.

[0038] The code pattern 2 has a light guide portion 5 and a non-light guide portion 6. The light guide portion 5 guides the light α emitted from the light irradiation portion 3 to the light receiving portion 4, and the non-light guide portion 6 blocks the light α emitted from the light irradiation portion 3. The code pattern 2 is a pattern array obtained by pseudo-random encoding the M sequence code, so that the light guide portion 5 and the non-light guide portion 6 represent position information.

[0039] In Implementation 1, the code pattern 2 is a pattern array that is set as Manchester code 17 by pseudo-random encoding of the M-sequence code representing position information using nine patterns. Hereinafter, the pseudo-random encoding of the M-sequence code representing position information as Manchester code 17 will be referred to as "Manchester code".

[0040] Furthermore, in Embodiment 1, the position information code 10, which is an M-sequence code, and the code obtained by Manchester encoding it are described, but other random codes are also possible. Additionally, the code representing position information is not limited to the M-sequence code; any code containing position information is acceptable, and it can be a code other than the M-sequence code. Similar to Manchester encoding, pseudo-random encoding inserts a code containing position information into a regular code sequence. Regarding the code pattern 2, if Manchester encoding is performed, it becomes a pattern array after the error correction code 16 is inserted. Conventionally, two columns of code patterns 2 are provided on the rotating plate 1 to eliminate positional ambiguity. However, by using Manchester encoding to insert the error correction code 16, only one column of code pattern 2 is needed, enabling miniaturization of the rotating plate 1.

[0041] The light-receiving unit 4 has 18 position detection light-receiving elements 11 for outputting position information of the rotating plate 1, and four position correction light-receiving elements 12 for outputting position information to correct errors. Conventionally, in the case of an M-sequence code representing the position of one cycle using 9 bits, only 18 light-receiving elements are used. Furthermore, to eliminate position ambiguity, light-receiving elements are conventionally prepared in two columns. However, for example, if Manchester encoding is performed, edge Ed can be detected, so a single-column structure is sufficient. Moreover, edge Ed (edge ​​signal) is effective for detecting error locations. In this embodiment, a structure of 18 position detection light-receiving elements 11 and four position correction light-receiving elements 12 for outputting position information to correct errors will be described, but the number of various light-receiving elements is not limited. In the light-receiving unit 4, light passing through the code pattern 2 and guided to each light-receiving element is converted into a light-receiving signal 7 obtained by binarizing it with "0" or "1".

[0042] The determination unit 8 compares the position information code 10 within each code cycle 13 of the converted light-receiving signal 7 with the error correction code 16, and determines whether an error exists in the converted light-receiving signal 7 by using the inverse relationship described later. If an error exists in the light-receiving signal 7, the error is determined. Furthermore, in the determination unit 8, based on the output value of the light-receiving signal 7, the Manchester code 17 is converted to the position information code 10, and the position information sequence 14 and correction information sequence 15 of the rotating plate 1 are calculated as output values. In addition, an arithmetic processing unit 30 is connected to the determination unit 8. The arithmetic processing unit 30 is a device that determines whether an error exists in the converted light-receiving signal 7 by using the inverse relationship shown below.

[0043] In the correction unit 9, the output value that is judged to be wrong by the determination unit 8 is corrected by XOR logic operation.

[0044] Next, use Figure 2 and Figure 3 This explains how to output position information code 10.

[0045] Light α emitted from the light irradiation unit 3 is irradiated onto the rotating plate 1. Light α irradiates the code pattern 2 on the rotating plate 1. The light α irradiating the code pattern 2 is reflected by the light guide unit 5 of the code pattern 2 and then incident on the light receiving unit 4.

[0046] In the light receiving unit 4, the light α received by the light receiving element 11 for position detection and the light receiving element 12 for position correction is converted into a light receiving signal 7 of 0 / 1.

[0047] Next, in the determination unit 8, it is determined whether there is an error in the light-receiving signal 7. Specifically, for the light-receiving signal 7, the error location of the converted light-receiving signal 7 is determined by using the inverse relationship between the position information code 10 and the error correction code 16 within each code cycle 13. Furthermore, the inverse relationship will be described later. Then, the light-receiving signal 7 is converted into the position information code 10.

[0048] If there is no error in the received light signal 7, the position information code 10 is output directly without correction in the correction unit 9. If there is an error, the correction unit 9 corrects the output value of the position information code 10 obtained by converting the error in the received light signal 7 as determined by the determination unit 8 using an XOR logic sum, and then outputs the correction. The correction in the case of an error will be described later.

[0049] In the absence of foreign matter in the code pattern 2, the position information code 10 obtained by the correction unit 9 becomes a code that contains either the code value "1" or "0" in each code cycle 13 and corresponds to the position information code of the code pattern 2.

[0050] Next, use Figure 4 The operating principle of the optical encoder 100 according to Embodiment 1 will be explained, namely, the encoding of the position information code 10 by inserting the error correction code 16 based on Manchester encoding. This operating principle is the principle of operation performed in the determination unit 8.

[0051] Error correction code 16 is used to help determine whether a false detection caused by a foreign object has occurred within code cycle 13 by comparing it with the position information code 10 within each code cycle 13. The code value changes according to the position information code 10 within each code cycle 13. When the code value corresponding to the light guide 5 of the position information code 10 is set to "1" and the code value corresponding to the non-light guide 6 is set to "0", the error correction code 16 is inserted by Manchester encoding such that the code value corresponding to the light guide 5 becomes "10" and the code value corresponding to the non-light guide 6 becomes "01". At this time, within code cycle 13, the inserted error correction code 16 establishes an opposite relationship with the adjacent position information code 10. The opposite relationship here means that the code value within a cycle is not the same output value as "11" or "00". An edge Ed is formed between the position information code 10 and the error correction code 16 within each code cycle 13. When the location information code 10 is "1", the edge Ed is detected as a signal where the output value decreases from 1 to 0 within code period 13. Conversely, when the location information code 10 is "0", the edge Ed is detected as a signal where the output value increases from 0 to 1 within code period 13.

[0052] According to this structure, even if the illumination light is blocked due to the intrusion of foreign matter, the erroneous part of the light-receiving signal 7 can be identified and corrected.

[0053] Figure 5A and Figure 5B This diagram illustrates a method for detecting erroneous parts when a portion of the light guide portion 5 or the non-light guide portion 6 of the code pattern 2 after Manchester encoding in Embodiment 1 is covered by a foreign object and false detection occurs. Figure 5A This diagram illustrates the error detection method in the determination unit 8 when a foreign object, which is a reflector 18, is mixed into the non-light guiding part 6 and guides light to the light receiving part 4. Figure 5B This diagram illustrates a method for detecting errors in the determination unit 8 when a foreign object, acting as a light-shielding material 19, is mixed into the light guide section 5 and blocks light.

[0054] The output value of the light signal 7 converted from light passing through the light guide section 5 and then through the light receiving section 4 is "1". The output value of the light signal 7 converted from light passing through the non-light guide section 6 and then through the light receiving section 4 is "0". The output value of the light signal 7 converted from light passing through the reflector 18 and then through the light receiving section 4 is "1". The output value of the light signal 7 converted from light passing through the light shield 19 and then through the light receiving section 4 is "0". Furthermore, in the absence of false detections caused by foreign objects, in this embodiment, the opposite relationship must hold within each code cycle 13, therefore the output value within the code cycle 13 must be either "10" or "01".

[0055] exist Figure 5A In the middle, due to reflector 18, the amount of light that should have been zero was detected by the light-receiving element (refer to...). Figure 5A When the intensity of the received light signal is high, "0" is output as "1", and the output value within code cycle 13 becomes "11". In this state, the two signal information are no longer inversely related, so it can be determined to be erroneous. Therefore, the received light signal 7 with an output of "11" in code cycle 13 can be determined to be erroneous (refer to...). Figure 5A (The error location).

[0056] exist Figure 5B In this state, due to the light-blocking object 19, insufficient light cannot be detected by the light-receiving element, so "1" is output as "0", and the output value within code cycle 13 becomes "00". In this state, the two signal information are no longer inversely related, so it can be determined that it is an error. Therefore, the light-receiving signal 7 with an output of "00" in code cycle 13 can be determined as an error.

[0057] Here, we illustrate the case where one part of the Manchester-encoded code pattern 2 is covered by a foreign object. However, even if two or more parts of the code pattern 2 are covered by foreign objects, the incorrect part can still be identified. Furthermore, Figure 5A and Figure 5B The determination shown is performed by the arithmetic processing unit 30.

[0058] Figure 6A and Figure 6B This is a diagram illustrating an example of the correction method performed by the correction unit 9. Figure 6A This is a diagram illustrating the use of the output values ​​at the beginning of correction information sequence 15. Figure 6B This is a diagram illustrating the use of the second output value starting from the beginning of the correction information sequence 15.

[0059] exist Figure 6A The method for correcting the output value is explained in the description of the determination unit 8 when it determines that the third output value from the beginning of the position information sequence 14 of the code pattern 2 is incorrect.

[0060] like Figure 6A As shown, the correction unit 9 acquires not only the nine output values ​​based on the position information sequence 14, but also two output values ​​based on the correction information sequence 15. These two output values ​​based on the correction information sequence 15, like the nine output values ​​based on the position information sequence 14, are output values ​​from the light-receiving unit 4. The two output values ​​based on the correction information sequence 15 are correction information used to correct the position information representing the position of the rotating plate 1, i.e., at least one of the nine output values.

[0061] In Embodiment 1, the output value at the beginning of the correction information sequence 15 is information used to correct one of the output values ​​determined as erroneous by the determination unit 8 among the first, third, fifth, sixth, seventh, and eighth output values ​​from the beginning of the position information sequence 14.

[0062] The first value is obtained by XORing the first value of position information sequence 14 with the third output value from the beginning. The second value is obtained by XORing the first value with the fifth output value from the beginning of position information sequence 14. The third value is obtained by XORing the second value with the sixth output value from the beginning of position information sequence 14. The fourth value is obtained by XORing the third value with the seventh output value from the beginning of position information sequence 14. The fifth value is obtained by XORing the fourth value with the eighth output value from the beginning of position information sequence 14. In this case, the output value at the beginning of correction information sequence 15 is equal to the fifth value.

[0063] For example, if the output value at the beginning of the correction information sequence 15 is "0", the sum of the output values ​​at the beginning, the third, the fifth, the sixth, the seventh and the eighth from the beginning of the position information sequence 14 is an even number.

[0064] On the other hand, when the output value of the correction information sequence 15 is "1", the sum of the first, third, fifth, sixth, seventh and eighth output values ​​of the position information sequence 14 is an odd number.

[0065] exist Figure 6AIn the sequence, the output value at the beginning of the correction information sequence 15 is "0". On the other hand, the total value of the first, third, fifth, sixth, seventh, and eighth output values ​​of the position information sequence 14 is "0" + "X" + "1" + "1" + "0" + "1" = "3 + X". Since the output value at the beginning of the correction information sequence 15 is "0", it can be determined that "3 + X" is an even number, and therefore "X" = "1".

[0066] Here, by using the above... Figure 5A The method has determined that the third output value from the beginning of the position information sequence 14 is incorrect. Therefore, the correction unit 9 outputs the third output value from the beginning of the position information sequence 14, including the first, third, fifth, sixth, seventh, and eighth output values, as "1".

[0067] exist Figure 6B The method for correcting the output value when the determination unit 8 determines that the fourth output value from the beginning of the position information sequence 14 is incorrect is explained.

[0068] like Figure 6B As shown, with Figure 6A Similarly, in the case shown, in addition to acquiring the nine output values ​​obtained based on the position information sequence 14, the correction unit 9 also acquires the two output values ​​obtained based on the correction information sequence 15.

[0069] In Implementation 1, the second output value from the beginning of the correction information sequence 15 is information used to correct one of the output values ​​that the determination unit 8 determines may be erroneous, based on the second, fourth, sixth, seventh, eighth and ninth output values ​​from the beginning of the position information sequence 14.

[0070] The sixth value is obtained by XORing the second output value from the beginning of position information sequence 14 with the fourth output value from the beginning. The seventh value is obtained by XORing the sixth value with the sixth output value from the beginning of position information sequence 14. The eighth value is obtained by XORing the seventh value with the seventh output value from the beginning of position information sequence 14. The ninth value is obtained by XORing the eighth value with the eighth output value from the beginning of position information sequence 14. The tenth value is obtained by XORing the ninth value with the ninth output value from the beginning of position information sequence 14. In this case, the second output value from the beginning of correction information sequence 15 is equal to the tenth value.

[0071] For example, if the second output value from the beginning of the correction information sequence 15 is "0", the sum of the output values ​​from the second, fourth, sixth, seventh, eighth and ninth output values ​​from the beginning of the position information sequence 14 is an even number.

[0072] On the other hand, when the second output value from the beginning of position information sequence 14 is "1", the sum of the output values ​​of the second, fourth, sixth, seventh, eighth and ninth outputs from the beginning of the first sort is an odd number.

[0073] exist Figure 6B In the correction information sequence 15, the second output value from the beginning is "0". On the other hand, the sum of the second, fourth, sixth, seventh, eighth, and ninth output values ​​from the beginning of the position information sequence 14 is "1" + "X" + "0" + "0" + "0" + "1" = "2 + X". Since the initial output value of the correction information sequence 15 is "0", it can be determined that "2 + X" is an even number, and therefore "X" = "0". Here, by using the above... Figure 5B The fourth output value from the beginning of the position information sequence 14 has been determined to be incorrect. Therefore, the correction unit 9 will output "0" as the fourth output value from the beginning of the second, fourth, sixth, seventh, eighth, and ninth output values ​​from the beginning of the position information sequence 14.

[0074] (Implementation Method 2)

[0075] In Embodiment 1, a Manchester encoding structure was described in which an error correction code 16 was inserted into the position information code 10 in the code pattern 2 on the rotating plate 1. However, the code pattern 2 can also be encoded without Manchester encoding, for example, by... Figure 7 The differential Manchester code 20 shown is constructed by performing pseudo-random encoding. Hereinafter, performing pseudo-random encoding using differential Manchester code 20 will be referred to as "performing differential Manchester encoding".

[0076] The optical encoder 200 of Embodiment 2 has the same basic structure as the optical encoder 100 of Embodiment 1, except that the code pattern 2 and the determination method in the determination unit 8 are different. Other structural parts and processing technology are the same as those of Embodiment 1, so descriptions are omitted.

[0077] Figure 7This diagram illustrates the operating principle of the optical encoder according to Embodiment 2, specifically the case after differential Manchester encoding of code pattern 2 (after pseudo-random encoding via differential Manchester encoding 20). Differential Manchester encoding has the following two characteristics. One characteristic is that, with each cycle advance of code period 13, the code value always changes from "0" to "1" or from "1" to "0". That is, the change occurs between "1" and "0" or "0" and "1" at the boundaries of adjacent cycles. The other characteristic is that when the original code, i.e., the code value of position information code 10, is "1", differential Manchester encoding changes the code value to "10" or "01" during code period 13. On the other hand, when the code value of position information code 10 is "0", differential Manchester encoding changes the code value to "11" or "00" during code period 13. That is, even if the code values ​​of position information code 10 are consecutively the same, they will not consecutively change to the same output value. For example, even if the code value of position information code 10 is consecutively "0" "0", the output value after differential Manchester encoding will not be consecutively "11" "11". In the second feature, as described above in this method, differential Manchester encoding also holds true when the conditions for "0" and "1" are reversed. Based on the above two features, for Figure 7 Code cycle 13 with an output of "11" has two adjacent code cycles 13 with outputs of "10" and "00" respectively, each functioning as error correction codes 16. This aforementioned relationship, where two adjacent code cycles 13 function as error correction codes 16, also holds true for all code patterns 2 after differential Manchester encoding. Furthermore, changes between "1" and "0" or "0" and "1" occur at the boundaries of adjacent cycles; therefore, changes in the signal at the boundaries of adjacent cycles can be designated as edge signals. Figure 7 In this context, the edge signal is denoted as edge Ed.

[0078] Figure 8A and Figure 8B This diagram illustrates a method for detecting erroneous parts when a portion of the light guide portion 5 or the non-light guide portion 6 of the code pattern 2 after differential Manchester encoding in Embodiment 2 is covered by a foreign object and false detection occurs. Figure 8A This diagram illustrates the error detection method in the determination unit 8 when a foreign object, which is a reflector 18, is mixed into the non-light guiding part 6 and guides light to the light receiving part 4. Figure 8B This diagram illustrates the error detection method in the determination unit 8 when a foreign object, which acts as a light-blocking agent 19, is mixed into the light guide section 5 and blocks light.

[0079] exist Figure 8AIn the middle, due to reflector 18, the amount of light that should have been zero was detected by the light-receiving element (refer to...). Figure 8A When the light intensity of the received signal is high, "0" is output as "1", and the output value within code cycle 13 becomes "01". In this state, the output value of the adjacent code cycle 13 is "11", and no change in code value is observed with the change of code cycle 13. Therefore, either or both of the received signal 7 within code cycle 13 with an output of "01" and the adjacent "11" can be determined as an error (see reference). Figure 8A (The error location).

[0080] exist Figure 8B In the middle, due to the light-blocking object 19, sufficient light cannot be detected by the light-receiving element (see reference). Figure 8B (The light intensity of the received signal), "1" is output as "0", and the output value within code cycle 13 becomes "00". In this state, the output value of the adjacent code cycle 13 is "10", and no change in code value is observed with the change of code cycle 13. Therefore, it is possible to determine that either or both of the light-receiving signal 7 within code cycle 13 with an output of "10" and the adjacent "00" are erroneous (see reference). Figure 8B (The error location).

[0081] Here, we explain the case where one part of code pattern 2 is covered by a foreign object. However, even if two or more parts of code pattern 2 are covered by foreign objects, the wrong part can still be identified.

[0082] Figure 9 This refers to the amount of light detected by the light-receiving element within the code cycle 13 arranged in the order of non-light-guiding part 6 and light-guiding part 5 in Embodiment 2, where the reflector 18 is mixed with non-light-guiding part 6 and the light-shielding part 19 is mixed with light-guiding part 5 (see reference). Figure 9 The diagram illustrates the method for detecting errors in a code cycle 13 when the output value is reversed due to a change in the light intensity of the received light signal.

[0083] Due to the reflector 18 and the light-blocking object 19, the output value within the code cycle 13, which was originally "01", is reversed to "10", and the output value within three consecutive code cycles 13 becomes "111000". Therefore, no change in code value was found between the code cycle 13 with output "11" and the code cycle 13 with output "10". Therefore, it is possible to determine any one or both of the light-receiving signals 7 within the code cycle 13 with output "11" and the adjacent code cycle 13 with output "10" as erroneous (see reference). Figure 9 (The incorrect part). In addition... Figure 9 The determination shown is performed by the arithmetic processing unit 30.

[0084] Furthermore, in the determination unit 8, the output value of the light-receiving signal 7 is converted into the position information code 10 to output the position information sequence 14 and the correction information sequence 15 of the rotating plate 1.

[0085] If the error location can be determined by the determination unit 8, the error location can be corrected by the method described in Embodiment 1.

[0086] (Implementation Method 3)

[0087] The embodiments described so far have illustrated a method for error detection using edge signals, but in Embodiment 3 and thereafter a method for determining the error location without using edge signals will be described.

[0088] In Embodiment 1, a structure is described in which an error correction code 16 is inserted every other position information code 10 by performing Manchester encoding on the code pattern 2 on the rotating plate 1. Alternatively, the structure could be one in which two error correction codes 16 are inserted every two position information codes 10.

[0089] The optical encoder 300 of Embodiment 3 has the same basic structure as the optical encoder 100 of Embodiment 1, except that the code pattern 2 and the determination method in the determination unit 8 are different. Other structural parts and processing technology are the same as those of Embodiment 1, so the description is omitted.

[0090] Figure 10 This diagram illustrates the operating principle of the optical encoder 300 according to Embodiment 3, specifically showing the encoding of inserting two error correction codes 16 every two position information codes 10 (see reference). Figure 10 The diagram shows the repeating code 24. Here, the code with the same output value as the two consecutive position information codes 10 before conversion is inserted as an error correction code 16, and the total of four codes, consisting of the two consecutive position information codes 10 and the two error correction codes 16, are set as one code cycle 13. That is, in embodiment 3, the code cycle is doubled compared to embodiment 1. Furthermore, the repeating code 24 corresponds to code pattern 2.

[0091] In the aforementioned encoding, the inserted error correction code 16 is linked to the adjacent position information code 10 within the code cycle 13 to establish a repetition relationship. This repetition relationship means that within each code cycle 13, the position information code 10 and the error correction code 16 repeat the same output value, such as "0000", "1010", "0101", and "1111". The output code patterns are limited to only the four aforementioned patterns; therefore, position information can be calculated by recognizing these four code patterns.

[0092] Figure 11A and Figure 11BThis diagram illustrates a method for detecting erroneous locations when a portion of the light guide portion 5 or the non-light guide portion 6 in Embodiment 3 is covered by a foreign object and false detection occurs. Figure 11A This diagram illustrates the error detection method in the determination unit 8 when a foreign object, acting as a reflector 18, is mixed into the non-light-guiding part 6 and guides light to the light-receiving part 4. Figure 11B This diagram illustrates the error detection method in the determination unit 8 when a foreign object, acting as a light-blocking material 19, is mixed into the light guide section 5 and blocks the light.

[0093] In the absence of false detections caused by foreign objects, the repetition relationship must hold within each code cycle 13. Therefore, the output value within each code cycle 13 must be any one of "0000", "1010", "0101", or "1111".

[0094] exist Figure 11A In the middle, due to reflector 18, the amount of light that should have been zero was detected by the light-receiving element (refer to...). Figure 11A The light intensity of the received signal (the light intensity of the received signal) is high, "0" is output as "1", and the output value within code cycle 13 becomes "1011". In this state, the four signal information are no longer repetitive, so it can be determined to be erroneous. Therefore, the light signal 7 with the output "1011" in code cycle 13 can be determined to be erroneous (refer to...). Figure 11A (The incorrect part). In addition... Figure 11A and Figure 11B The determination shown is performed by the arithmetic processing unit 30.

[0095] exist Figure 11B In the middle, due to the light-blocking object 19, sufficient light cannot be detected by the light-receiving element (see reference). Figure 11B (The light intensity of the received signal), "1" is output as "0", and the output value within code cycle 13 becomes "1000". In this state, the two signal information are no longer repetitive, so it can be determined as an error (refer to...). Figure 11B (The error location). Therefore, the light signal 7 with the code cycle 13 outputting "1000" can be determined as an error.

[0096] Here, we explain the case where one part of code pattern 2 is covered by a foreign object. However, even if two or more parts of code pattern 2 are covered by foreign objects, the wrong part can still be identified.

[0097] Furthermore, in the determination unit 8, the output value of the light-receiving signal 7 is converted into the position information code 10 to output the position information sequence 14 and the correction information sequence 15 of the rotating plate 1.

[0098] If the error location can be determined by the determination unit 8, the error location can be corrected by the method described in Embodiment 1.

[0099] (Implementation Method 4)

[0100] In embodiment 3, a structure in which two error correction codes 16 are inserted every two position information codes 10 is described, but it is also possible to insert one error correction code 16 every two position information codes 10.

[0101] The optical encoder 400 of Embodiment 4 has the same basic structure as the optical encoder 100 of Embodiment 1, except that the code pattern 2 and the determination method in the determination unit 8 are different. Other structural parts and processing technology are the same as those of Embodiment 1, so the description is omitted.

[0102] Figure 12 This diagram illustrates the operating principle of the optical encoder 400 according to Embodiment 4, specifically explaining the encoding where an error correction code 16 is inserted every two position information codes 10 (see reference). Figure 12 The diagram shows the converted repeating code 25. Here, an error correction code 16 is inserted, which outputs a value corresponding to the value output by the two consecutive position information codes 10 before conversion. The encoding is a code cycle 13 consisting of three codes formed by combining two consecutive position information codes 10 and one error correction code 16. Furthermore, the repeating code 25 corresponds to code pattern 2.

[0103] The inserted error correction code 16 establishes a correspondence with the two position information codes 10 within each code cycle 13. This correspondence means that when the position information code 10 is "11" or "10", a "1" is inserted as the error correction code 16. Furthermore, when the position information code 10 is "01" or "00", a "0" is inserted as the error correction code 16. Therefore, within each code cycle 13, the position information code 10 and the error correction code 16 must represent any one of the output values ​​"111", "101", "010", or "000". Since the output code patterns are only the aforementioned four, the position information can be calculated by recognizing these four code patterns.

[0104] Figure 13A and Figure 13B This diagram illustrates a method for detecting erroneous locations when a portion of the light guide portion 5 or the non-light guide portion 6 in Embodiment 4 is covered by a foreign object and false detection occurs. Figure 13A This diagram illustrates a method for detecting errors when a foreign object, acting as a reflector 18, is mixed into the non-light-guiding section 6 and guides light to the light-receiving section 4. Figure 13B This diagram illustrates the error detection method in the determination unit 8 when a foreign object, acting as a light-blocking material 19, is mixed into the light guide section 5 and blocks the light.

[0105] In the absence of false detections caused by foreign objects, the correspondence must hold within each code cycle 13. Therefore, the output value within each code cycle 13 must be any one of "111", "101", "010", or "000".

[0106] exist Figure 13A In the middle, due to reflector 18, the amount of light that should have been zero is detected by the light-receiving element (refer to...). Figure 13A The light intensity of the received signal (the light intensity of the received signal) is high, "0" is output as "1", and the output value within code cycle 13 becomes "100". In this state, the three signal information are out of correspondence, so it can be determined to be erroneous. Therefore, the light signal 7 with an output of "100" in code cycle 13 can be determined to be erroneous (refer to...). Figure 13A (The error location).

[0107] exist Figure 13B In the middle, due to the light-blocking object 19, insufficient light cannot be detected by the light-receiving element, and "1" is output as "0" (refer to...). Figure 13B The light intensity of the received signal), and the output value during code cycle 13 becomes "100". In this state, the three signal information are no longer inversely related, so it can be determined to be erroneous. Therefore, the light-receiving signal 7 with an output of "100" during code cycle 13 can be determined to be erroneous (see reference). Figure 13B (The incorrect part). In addition... Figure 13A and Figure 13B The determination shown is performed by the arithmetic processing unit 30.

[0108] Here, we explain the case where one part of code pattern 2 is covered by a foreign object. However, even if two or more parts of code pattern 2 are covered by foreign objects, the wrong part can still be identified.

[0109] Furthermore, in the determination unit 8, the output value of the light-receiving signal 7 is converted into the position information code 10 to output the position information sequence 14 and the correction information sequence 15 of the rotating plate 1.

[0110] If the error location can be determined by the determination unit 8, the error location can be corrected by the method described in Embodiment 1.

[0111] In Embodiment 1, a structure is described that inserts one error correction code 16 for each location information code 10. In Embodiment 3, a structure is described that inserts two error correction codes 16 for each of two location information codes 10. In Embodiment 4, a structure is described that inserts one error correction code 16 for each of two location information codes 10. The number of location information codes 10 and their corresponding error correction codes 16 is not limited to the four methods described above. For example, the array of code pattern 2 can also be an array in which Y error correction codes 16 are inserted for every X (X is a natural number) location information codes 10 in the location information data string.

[0112] (Implementation Method 5)

[0113] In embodiments 1, 2, 3, and 4, the light-receiving unit 4 is composed of a light-receiving element 11 for position detection that outputs position information and a light-receiving element 12 for position correction that outputs error correction information. However, as long as position information and error correction information can be output, an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) sensor or a CCD (Charge Coupled Device) sensor, which has areas for outputting position information and areas for outputting error correction information respectively, can be used instead of the light-receiving element. In embodiments 1, 2, 3, 4, and this embodiment, it can be applied to any type of optical encoder, including reflective and transmissive types. If it is a transmissive optical encoder, the light-illuminating unit 3, the rotating plate 1, and the light-receiving unit 4 are configured as a transmissive optical unit, which can be achieved by setting the light guide unit 5 as a transmissive unit and the non-light guide unit 6 as a non-transmissive unit. If it is a reflective optical encoder, then the light irradiation part 3, the rotating plate 1, and the light receiving part 4 are configured as reflective optical components. This can be achieved by simply setting the light guide part 5 as a reflective part and the non-light guide part 6 as a non-reflective part. If the above structure is used to construct both transmissive and reflective optical encoders, then the materials and manufacturing methods of each component are not limited.

[0114] (Implementation Method 6)

[0115] The rotary encoder described in embodiments 1 to 5 above is not limited to rotary encoders; it can also be applied to other types of encoders. Figure 14A and Figure 14B The linear encoder shown.

[0116] Figure 14A This is a schematic diagram illustrating an example of the optical encoder 500 according to Embodiment 6. Additionally, Figure 14BThis is a perspective view of the moving body 23 of the optical encoder 500 according to Embodiment 6. The difference from Embodiment 1 is that the moving body 23 is used instead of the rotating body 21.

[0117] The moving body 23 moves in a straight line. A code pattern 2 is provided on the surface of the moving body 23. The code pattern 2 has a straight, strip-like shape. A light irradiation unit 3 and a light-receiving unit 4 are provided on the main surface of the fixed part 22, facing the code pattern 2. A determination unit 8 and a correction unit 9 are provided on the surface of the fixed part 22 opposite to the main surface where the light irradiation unit 3 and the light-receiving unit 4 are provided. The light irradiation unit 3, for example, has an LED (Light Emitting Diode). The light-receiving unit 4, for example, has a light-receiving element. Light α emitted from the LED of the light irradiation unit 3 irradiates the code pattern 2, and the light-receiving element of the light-receiving unit 4 receives the light α reflected back by the code pattern 2. The light-receiving unit 4, the determination unit 8, and the correction unit 9 are electrically connected. The determination unit 8, for example, includes electronic circuitry. The determination unit 8 processes the signal of the light α received by the light-receiving element of the light-receiving unit 4. The correction unit 9, for example, includes electronic circuitry. The correction unit 9 processes the signal from the determination unit 8.

[0118] The operation of the optical encoder 500 according to Embodiment 6 is the same as the operation of the optical encoder 100 according to Embodiment 1.

[0119] Furthermore, this embodiment, like embodiments 1 to 5, can also be applied to any type of optical encoder, including reflective and transmissive types. As long as the transmissive and reflective optical encoders are constructed using the above-described structure, the materials and manufacturing methods of each structure are not limited.

[0120] Industrial availability

[0121] The encoder disclosed herein can be used to detect the rotation of the rotating shaft of a motor that drives a load to rotate. Furthermore, the encoder disclosed herein can be used to detect the position of an object moving in a straight line.

[0122] Explanation of reference numerals in the attached figures

[0123] 1: Rotating plate; 2: Code pattern; 3: Light irradiation part; 4: Light receiving part; 5: Light guiding part; 6: Non-light guiding part; 7: Light receiving signal; 8: Judgment part; 9: Correction part; 10: Position information code; 11: Light receiving element for position detection; 12: Light receiving element for position correction; 13: Code cycle; 14: Position information sequence; 15: Correction information sequence; 16: Error correction code; 17: Manchester code; 18: Reflector; 19: Light blocking object; 20: Differential Manchester code; 21: Rotating body; 22: Fixed part; 23: Moving body; 24, 25: Repeat code; 30: Processing unit; 100, 200, 300, 400, 500: Optical encoder; SH: Rotating shaft.

Claims

1. An encoder, comprising: A mobile board having a code pattern, the code pattern having location information; A light irradiation unit that irradiates light onto the code pattern; The light-receiving part receives light emitted from the light-irradiating part and passing through the code pattern; and The determination unit determines whether there is an error in the position information output by the light-receiving unit. in, The code pattern is composed of a light guide portion and a non-light guide portion. The light guide portion guides the light emitted from the light irradiation portion to the light receiving portion, while the non-light guide portion does not guide the light emitted from the light irradiation portion to the light receiving portion. The array of code patterns is an array in which Y error correction codes are inserted every X position information codes in the position information data string, where X and Y are natural numbers. There is a correspondence between the location information code and the adjacent error correction code. The light-receiving part includes: A light-receiving element for position detection, which reads the array of the code pattern; and A position correction light-receiving element receives light passing through the code pattern, converts the received light into a light-receiving signal, and outputs the light-receiving signal as information for correcting the error.

2. The encoder according to claim 1, characterized in that, The code pattern is formed on a rotating plate.

3. The encoder according to claim 1 or 2, characterized in that, It also includes a correction unit that corrects results that are determined to be erroneous by the determination unit.

4. The encoder according to claim 1 or 2, characterized in that, The array of the code pattern is obtained by inserting the error correction code into the location information data string using Manchester encoding.

5. The encoder according to claim 1 or 2, characterized in that, The array of the code pattern is obtained by inserting the error correction code into the location information data string using differential Manchester encoding.

6. The encoder according to claim 1 or 2, characterized in that, The light-receiving part includes an image sensor, which has a position detection area for outputting position information of the code pattern and a position correction area for outputting information for correcting errors.

7. An encoder, comprising: A mobile board having a code pattern, the code pattern having a location information code and an adjacent error correction code; An irradiation section that irradiates light onto the code pattern; A light-receiving part receives light emitted from the irradiating part and passing through the code pattern; The determination unit determines the erroneous part in the signal originating from the code pattern based on the relationship between the signal originating from the location information code and the signal originating from the error correction code. as well as The correction unit corrects the errors identified by the determination unit. The determination unit includes a calculation processing unit. When the error correction code is appended to the code pattern based on the code value of consecutive arbitrary position information codes, and there is a correspondence between the position information codes and adjacent error correction codes, the calculation processing unit performs a calculation using the correspondence, and the determination unit determines the error location based on the result of the calculation.

8. The encoder according to claim 7, characterized in that, The code pattern is formed by inserting the error correction code into the location information data string composed of the location information code using Manchester encoding. When there is an inverse relationship between the location information code and the adjacent error correction code, the arithmetic processing unit performs an operation utilizing the inverse relationship. The determination unit determines the error location based on the result of the calculation.

9. The encoder according to claim 7, characterized in that, The code pattern is formed by inserting the error correction code into the location information data string composed of the location information code using differential Manchester encoding. When a code value change occurs during code cycle switching, the arithmetic processing unit performs calculations utilizing the code value change. The determination unit determines the error location based on the result of the calculation.

10. An information processing method, wherein the information processing method is performed in an encoder, the encoder having a movable plate having a code pattern, the code pattern having a position information code and an adjacent error correction code, the information processing method comprising the following steps: The determination step involves identifying the erroneous part of the signal originating from the code pattern based on the relationship between the signal originating from the location information code and the signal originating from the error correction code. as well as The correction step involves correcting the erroneous parts identified in the judgment step. The determination step includes: when the error correction code is appended to the code pattern according to the code value of consecutive arbitrary position information codes and there is a correspondence between the position information code and the adjacent error correction code, performing an operation that utilizes the correspondence, and determining the error location based on the result of the operation.

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