JP2010160147A - Single-track type optical encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the problem of alignment between an encoder scale and a photodetector by forming an encoder to have a single-track constitution. <P>SOLUTION: A reflection type optical encoder 10 includes a single-track type photodetector 48 and a code scale 30. The single-track type photodetector 48 includes a common axis 47 and is constituted of photodetectors A' and B' 24 for A and B data and photodetectors 20a and 20b for index channels I and I'. The code scale 30 includes an index and a data strip 31 and 33. The code scale 30 is so disposed that part of light radiated from a luminescent body is reflected onto the photodetectors 20a, 20b and 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

[Cross-reference with related applications]
This patent application was filed on the same date as US Patent Application No. ____ to Yee Loong Chin et al., Entitled “Optical Encoder Systems, Devices and Methods”. The entirety of that patent is incorporated herein by reference.

[Field of the Invention]
Various embodiments of the invention described herein relate to optical encoders and related components, apparatus, systems and methods.

  Optical encoders are commonly used as motion detectors in applications such as closed loop feedback control in motor control systems. As an example, many optical encoders are configured to convert rotational or linear motion into a two-channel digital output to encode position.

  Many optical encoders use LEDs as light sources. In a transmissive encoder, the light is collimated into a parallel beam by a lens placed on the LED. On the opposite side of the light emitter, there is typically a photodetector comprised of a photodiode array and a signal processor. When a code scale, such as a code wheel or a code strip, moves between the emitter and the photodetector, the light beam is interrupted by a pattern of bars and spaces arranged on the code scale. The Similarly, in a reflective or imaging encoder, the lens on the LED focuses the light on the code scale. The light is either reflected or not reflected towards the lens located on the photodetector. As the chord scale moves, alternating patterns of light and dark patterns corresponding to bars and spaces hit the photodiode. The photodiode detects these patterns and the corresponding output is processed by a signal processor to generate a digital waveform. The output of such an encoder is used, as an example, to provide information regarding motor position, speed and acceleration.

  The three-channel optical encoder is provided with an index channel photodetector having photodiode arrays I and I '. Here, the index channel photodetectors are not aligned with the axis of the data channel and are offset laterally from them. However, such an encoder requires a large surface area and package dimensions to be realized, and considering that the photodetector requires a large surface area, it is between the code scale and the photodetector. The possibility of misalignment increases. In such a method, a dedicated optical alignment apparatus and process are required, so that the manufacturing cost and time are generally increased. See, for example, US Pat. No. 4,451,731 to Leonard.

  A two-channel light reflective encoder is disclosed in US Pat. No. 7,394,061 to Bin Saidan et al. (Hereinafter referred to as the “'061 patent”). In this' 061 patent, the output signal of the third index channel is provided through a relatively complex processing of signals corresponding to the A, A ', B and B' data channels. In such an encoder, considerable resources and time need to be devoted to designing the complex output circuitry required to generate the index channel output signal. Further, the output provided by the data and index channels can be degraded if the total current generated by the photodetector is not sufficient to generate the required output signal. As a result, at least some pairs of A, A ', B and B' channels cannot be used to generate an index channel output signal. At higher resolutions, the width of the photodetector for the data channel and the corresponding surface area are small, and the current they generate is insufficient to generate an index output pulse, so the '061 patent two-channel design Cannot be realized. Therefore, another electronic circuit is required to increase the photodiode current.

  The market is constantly demanding smaller, higher resolution light reflective encoders. What is needed is a smaller, higher resolution light reflective encoder that can be provided without the use of complex and expensive signal processing output circuitry.

  Various patents, including content directly or indirectly related to the field of the present invention, include, but are not limited to: US patent to Leonard, May 29, 1984 U.S. Pat. No. 4,451,731, June 10, 2008, U.S. Pat. No. 7,182,248 to Foo et al., U.S. Pat. No. 7,385,178 to Ng et al. U.S. Patent No. 7,400,269 to Wong et al., July 15, 2008, U.S. Patent No. 7,394,061 to Saidan et al., July 1, 2008, October 2006 US Patent Application No. 2006/0237540 to Saxena et al., 26 US Patent Application No. 2008/0024797 to Otsuka et al., Jan. 21, 2008.

  The date posted above corresponds to any one of the priority date, application date, publication date and issue date. The above list of patents and patent applications in this background art section is not approved by the applicant or his attorney, and one or more publications from the above list are prior art with respect to the applicant's various inventions. Should not be interpreted as constituting. The entirety of each and every printed publication or patent referred to in this application is hereby incorporated by reference.

  Upon reading and understanding the "Summary of Invention", "Mode for Carrying Out the Invention" and "Claims" described below, those skilled in the art will be able to It will be appreciated that at least some of the disclosed systems, devices, components and methods can be suitably modified based on the teachings of the various embodiments of the present invention.

  In some embodiments, a reflective optical encoder is provided. The reflective optical encoder has a substrate having a top surface, a light emitter attached to or attached to the top surface and configured to emit light therefrom, and a common axis, and A and A along the common axis. A plurality of alternating sequences of pairs of B data channel photodetectors and A ′ and B ′ data channel photodetectors and at least a pair of index channel I and I ′ photodetectors mounted on the top surface A and A ′ and B with a single-track photodetector mounted or mounted, and a code scale having an index and a data strip and configured to move along a common axis And B ′ photodetectors are arranged 90 degrees out of phase with each other and arranged and configured to allow the code scale to operate with a single track photodetector to emit light. At least a portion of the emitted light is reflected toward the code scale photodetector data channel and index channel from.

  In another embodiment, a method for making a reflective optical encoder is provided. The method includes providing a substrate having a top surface, attaching or mounting a light emitter to the top surface, and having a common axis associated with the light for the A and B data channels along the common axis. A top view of a single track photodetector with a plurality of alternating sequences of pairs of detectors and photodetectors for A ′ and B ′ data channels and at least one pair of index channel I and I ′ photodetectors. Attaching to or attaching to the single-track photodetector and positioning the code scale relative to the single-track photodetector, the A and A ′ photodetectors and the B and B ′ photodetectors. The instruments are arranged 90 degrees out of phase with each other, the code scale has an index and a data strip, the code scale moves along a common axis, At least a portion of the light emitted from the body is reflected toward the code scale photodetector data channel and index channel.

  Still other embodiments will be apparent to those of ordinary skill in the art upon reading and understanding the specification and the drawings.

  Various aspects of various embodiments of the present invention will become apparent from the following specification, drawings, and claims.

1 is a diagram showing a first embodiment of a reflective optical encoder 10 of the present invention. FIG. 2 shows an exemplary output signal provided by the embodiment of FIG. It is a figure which shows 2nd Embodiment of the reflective optical encoder 10 of this invention. FIG. 4 illustrates an exemplary output signal provided by the embodiment of FIG. It is a figure which shows 3rd Embodiment of the reflective optical encoder 10 of this invention. FIG. 6 illustrates an exemplary output signal provided by the embodiment of FIG. It is a figure which shows 4th Embodiment of the reflective optical encoder 10 of this invention. FIG. 8 illustrates an exemplary output signal provided by the embodiment of FIG.

  These drawings are not necessarily drawn to scale. The same numbers refer to the same parts or steps throughout the drawings, unless otherwise specified.

  In various embodiments of the present invention, a single track reflective optical encoder system, apparatus and method are provided.

  The term “single track encoder” as used herein means an optical encoder with a single code scale. This single code scale has a data or code pattern or bar and index pattern or bar formed or provided thereon or in the data and index pattern. Move together along a common single axis within a single track, positioned on a corresponding single track with a detector.

  FIG. 1 illustrates one embodiment of a reflective optical encoder 10. Here, a single track photodetector 48 is attached or mounted on the top surface of a substrate (not shown in FIG. 1). A light emitter (also not shown) is also attached or attached to the top surface of the substrate and configured to emit light therefrom. The single track photodetector 48 has a common axis 47. A plurality of alternating sequences of pairs of A and B data channel photodetectors and A ′ and B ′ data channel photodetectors 24, and at least one pair of index channel I and I ′ photodetectors 20a and 20b, Arranged along the common axis 47. The index channel photodetectors are arranged at opposite ends 43 and 45 of a single track photodetector 48 according to the embodiment of FIG. Each pair of A and A 'and B and B' data channel photodetectors 24 are arranged 90 degrees out of phase with each other. Code scale 30 includes index and data strips 31 and 33. This code scale is configured to move forward and / or backward along axis 49, depending on the particular application at hand. The axis 49 of the code scale 30 is at least approximately coincident and parallel to the corresponding axis 47 of the single track photodetector 48. The code scale 30 is single tracked so that at least a portion of the light emitted from the light emitter is reflected from the code scale 30 toward the data and index channel photodetectors 24, 20a and 20b. Arranged and configured to operate with photodetector 48.

  As further shown in the embodiment of FIG. 1, each of the data channel photodetectors A, A ′, B and B ′ (24) is approximately equal to “PD” (ie, “photodetector”). The index channel I photodetector 20b has a second width equal to about four times PD, and the index channel I ′ photodetector 20a has about PD 3. It has a third width equal to twice. Other widths for the index channel photodetectors I (20b) and I '(20a) can also be used as shown in FIGS. The widths for the index channel photodetectors I (20b) and I ′ (20a) are the width of the index scale 31 on the code scale 30 and the index channel photodetectors I (20b) and I ′ (20a). ) Is selected to produce an output pulse 26 having a width of 360 degrees with respect to the output signals 22 and 24 provided by the data channel photodetectors A, A ′, B and B ′ 25. Preferably (see FIG. 2). In the embodiment of FIGS. 1 and 2, the width of the index scale 31 is equal to 6 times the PD, but each pair of reflective (ie, bright) and non-reflective (ie, dark) data strips 33 is the PD's. It has a combined width corresponding to 4 times. Thus, the ratio of the two widths shown in FIG. 1 (ie, the combined width of the index strip 31 / the light / dark pair of the data strip 33) is 1.5. Other ratios for the width of the index strip and data strip are about 2.5 (ie, about 10 times PD / 4 times PD), about 3.5 (ie, about 14 times PD / PD 4). Times), and about 4.5 (that is, about 18 times PD / four times PD).

  Further, as further shown in the embodiment of FIG. 1, the height H of the index channel photodetectors I (20b) and I ′ (20a) is determined by the individual data channel photodetectors A. , A ′, B and B ′ are different from the height h. In the embodiment of FIG. 1, the data channel photodetector 24 has a first height h, and the index channel I photodetector 20b has a second height corresponding to about 1.5 times h. And the index channel I ′ photodetector 20a has a third height equal to about 0.9 times h. Other heights for the index channel photodetectors I and I 'can also be used, as shown in FIGS. Alternative height embodiments for the index channel photodetectors I (20b) and I '(20a) are about twice, about three times, or about four times the height of the individual data channel photodetectors 24. Greater than twice.

  In various embodiments of the reflective optical encoder 10, the height H of one or more index channel photodetectors I (20b) and index channel photodetectors I '(20a) is determined as the data channel light. With respect to the corresponding height of the detector 24, there is no need to provide additional electronics to increase the current provided by the I and I ′ photodetectors, and the index channel photodetector I ( It is possible to provide a sufficient voltage output from the channel I comparator 25 corresponding to 20b) and I ′ (20a).

  Those skilled in the art will now disclose the index channel photodetector, the data channel photodetector, and the preferred almost infinite permutations and combinations of code wheel index and data strip widths and heights herein. It will be understood that it can be used based on the teachings made.

  In the reflective single-track optical encoder, at least one height of the index channel photodetector I (20b) and the index channel photodetector I ′ (20a) corresponds to the corresponding data channel photodetector 24. A line / inch ("LPI") resolution greater than about 100 LPI, about 200 LPI, about 250 LPI, and / or about 300 LPI cannot be reliably obtained if it is not at least about 1.5 times the height of Has been discovered.

  The term “resolution”, as used herein, refers to the basic resolution achieved by the optical encoder 10, such as a digital signal processor (“DSP”), processor, microprocessor, CPU. The output signals 22, 24 and 26 provided by the encoder 10 using an application specific integrated circuit ("ASIC"), integrated circuit ("IC") or any other suitable signal processing or computer electronics. Is the resolution before any processing is performed later. Such processing techniques can further extend the basic or basic resolution provided by the encoder 10. As further shown in the embodiment of FIG. 1, the A and A ′ data channels, the B and B ′ data channels, and the I and I ′ index channels are respectively a channel A comparator 21 and a channel B comparator. 23 and a channel I comparator 25, respectively, are operatively connected to provide analog comparators A and A ′, B and B ′, and I and I ′ pairs, respectively, to the comparators. Comparators 21, 23 and 25 compare each analog signal pair provided thereto by a single channel photodetector 48 and, as shown in FIG. 2, digital output signals 22, 24 and 26 from there.

  Referring now to FIG. 2, it can be seen that the channel A comparator 21 compares the analog signals delivered by the data channels A and A 'and provides a digital output signal 22. This output signal 22 is for channels A and A ′ where the code scale 30 moves over a single track photodetector 48 and the light emitted by the illuminant is located along a common axis 47. FIG. 4 is a train of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. Similarly, the channel B comparator 23 provides a digital output signal 24 by comparing the analog signals delivered by the data channels B and B '. This output signal 24 is for channels B and B ′ in which the code scale 30 moves over a single track photodetector 48 and the light emitted by the light emitters is located along a common axis 47. FIG. 4 is a train of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. As shown in FIG. 2, the output signals 22 and 24 are approximately 90 degrees out of phase with each other. Channel I comparator 25 provides a digital output signal 26 by comparing the analog signals delivered by index channels I and I '. The output signal 26 is an index output pulse that is significantly wider than the data output pulses 22 and 24 provided by the channel A and B comparators 21 and 23, and in one embodiment, the data output pulses 22 and 24. It has a width of about 360 degrees with respect to the width.

  The index strip 31 in FIG. 1 shows six strips of opaque areas arranged side by side above the alternating bar and window areas corresponding to the data strip 33. As the code scale 30 moves relative to the single track photodetector 48, an analog signal is generated by the index channel I photodetector 20b and the index channel I 'photodetector 20a. In another method, the index channel I photodetector 20b generates a high level signal. A low level signal is generated when the six opaque regions of the index strip 33 are aligned with the photodiodes of the index channel I photodetector 20b.

  Referring to FIG. 2, channel I digital output signal 26 is generated by signal processing when both analog photodiode I signal 27 and analog photodiode I 'signal 29 cross over each other. The same principle applies to the digital index channel output signal 26 shown in FIGS.

  The light emitter, single track photodetector 48, and code scale 30 of the embodiment of FIG. 1 has a resolution that the encoder 20 exceeds about 100 lines / inch (LPI), about 150 LPI, about 200 LPI, or about 300 LPI. Note that they can be tailored to provide.

  In various embodiments, the reflective optical encoder 10 comprises a dome lens composed of an optically transparent material, and is optically disposed between a light emitter and a single track photodetector 38. An opaque light barrier can also be provided. The light barrier is configured to prevent or block stray light from entering the single track photodetector 38. The data channel photodetector 24 and the index channel photodetectors 20a and 20b may be located on a single integrated circuit die. The substrate on which the illuminator and single track photodetector 48 are disposed can be a printed circuit board and the lead frame can be constructed from plastic or from polymer or any other suitable composition or material.

  Referring to FIG. 3, another embodiment of the reflective optical encoder 10 is shown. In this embodiment, a single track photodetector 48 is attached or mounted on the top surface of the substrate (not shown in FIG. 3). A light emitter (also not shown) is also attached or attached to the top surface, and in one aspect, is configured to emit light therefrom. The single track photodetector 48 has a common axis 47. A plurality of alternating sequences of pairs of A and B data channel photodetectors and A ′ and B ′ data channel photodetectors 24, and two index channel I ′ photodetectors 20a and one index channel I The optical detector 20 b is disposed along the common axis 47. This index channel photodetector is located at the opposite ends 43 and 45 of the single track photodetector 48 according to the embodiment of FIG. Each pair of A and A 'and B and B' data channel photodetectors 24 are arranged 90 degrees out of phase with each other. Code scale 30 includes index and data strips 31 and 33. This code scale is configured to move forward and / or backward along axis 49, depending on the particular application at hand. The axis 49 of the code scale 30 is at least approximately coincident and parallel to the corresponding axis 47 of the single track photodetector 48. The code scale 30 is single tracked so that at least a portion of the light emitted from the light emitter is reflected from the code scale 30 toward the data and index channel photodetectors 24, 20a and 20b. Arranged and configured to operate with photodetector 48.

  As further shown in the embodiment of FIG. 3, each of the data channel photodetectors A, A ′, B and B ′ (24) is approximately equal to “PD” (ie, “photodetector”). Index channel I photodetector 20b has a first width equal to approximately PD, and index channel I ′ photodetector 20a equals approximately four times PD. It has a second width.

  As further shown in the embodiment of FIG. 3, the height H of the index channel photodetectors I (20b) and I ′ (20a) is determined by the individual data channel photodetectors A, A ′, It is different from the height h of B and B ′. In the embodiment of FIG. 3, the height of the data channel photodetector 24 is the first height h, while the height of the index channel I photodetector 20b and the index channel I ′ photodetector 20a. Is a second height equal to about 1.5 times h. In the embodiment shown in FIG. 3, the index channel I ′ photodetector comprises two separate photodetectors 20a, the width of each photodetector being PD, separated by a distance PD. Note that In the embodiment shown in FIG. 3, the width of the index strip 31 is 6 times the PD, while the width of the data strip is twice the PD.

  As further shown in the embodiment of FIG. 3, the A and A ′ data channels, the B and B ′ data channels, and the I and I ′ index channels are respectively a channel A comparator 21 and a channel B comparator 23. , And operably connected to the channel I comparator 25 to provide pairs of analog signals A and A ′, B and B ′, and I and I ′, respectively, to the comparators. Comparators 21, 23 and 25 compare each analog signal pair provided thereto by a single channel photodetector 48 and, as shown in FIG. 4, digital output signals 22, 24 and 26, respectively. From there.

  Referring to FIG. 4, it can be seen that the channel A comparator 21 compares the analog signals delivered by the data channels A and A 'to provide a digital output signal 22. This output signal 22 is for channels A and A ′ where the code scale 30 moves over a single track photodetector 48 and the light emitted by the illuminant is located along a common axis 47. A series of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. Similarly, the channel B comparator 23 provides a digital output signal 24 by comparing the analog signals delivered by the data channels B and B '. This output signal 24 is for channels B and B ′ in which the code scale 30 moves over a single track photodetector 48 and the light emitted by the light emitters is located along a common axis 47. A series of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. As shown in FIG. 4, the output signals 22 and 24 are approximately 90 degrees out of phase with each other. Channel I comparator 25 provides a digital output signal 26 by comparing the analog signals delivered by index channels I and I '. This output signal 26 is an index output pulse that is considerably wider than the data output pulses 22 and 24 provided by the comparators 21 and 23 for the channels A and B, and is approximately 360 with respect to the width of the data output pulses 22 and 24. Have a width of degrees.

  The light emitter, single track photodetector 48 and code scale 30 of the embodiment of FIG. 3 provides a resolution that the encoder 20 exceeds about 100 lines per inch (LPI), about 150 LPI, about 200 LPI, or about 300 LPI. Note that it can be configured as much as possible.

  Referring now to FIG. 5, another embodiment of the reflective optical encoder 10 is shown. In this embodiment, a single track photodetector 48 is attached or mounted on the top surface of the substrate (not shown in FIG. 5). A light emitter (also not shown) is also attached or attached to the top surface, and in one aspect, is configured to emit light therefrom. The single track photodetector 48 has a common axis 47. A plurality of alternating sequences of pairs of A and B data channel photodetectors and A ′ and B ′ data channel photodetectors, four indices arranged in the central portion 41 of a single track photodetector 48 The channel I photodetector 20b and, according to the embodiment of FIG. 5, the two index channel I ′ lights arranged at the opposite ends 43 and 45 of the single track photodetector 48, respectively. The detector 20 a is arranged along the common axis 47. Each pair of A and A 'and B and B' data channel photodetectors 24 are arranged 90 degrees out of phase with each other. The code scale 30 has index and data strips 31 and 33. This code scale is configured to move forward and / or backward along axis 49, depending on the particular application at hand. The axis 49 of the code scale 30 is at least approximately coincident and parallel to the corresponding axis 45 of the single track photodetector 48. The code scale 30 is single tracked so that at least a portion of the light emitted from the light emitter is reflected from the code scale 30 toward the data and index channel photodetectors 24, 20a and 20b. Arranged and configured to operate with photodetector 48.

  As further illustrated in the embodiment of FIG. 5, each of the data channel photodetectors A, A ′, B and B ′ (24) has a first width equal to about “PD”; On the other hand, the index channel I photodetector 20b has a width equal to about four times PD, and the index channel I ′ photodetector 20a has a width equal to about twice PD.

  As further shown in the embodiment of FIG. 5, the height H of the index channel photodetector I (20b) is determined by the individual data channel photodetectors A, A ′, B and B ′, and This is different from the height h of the index channel I ′ photodetector 20a. In the embodiment of FIG. 5, the height of the data channel photodetector 24 and the index channel I ′ photodetector 20a is the first height h, while the index channel I photodetector 20b and the index. The height of the photodetector for channel I ′ 20b is a second height equal to about twice h. In the embodiment shown in FIG. 5, the index channel I ′ photodetector comprises two separate photodetectors 20a, each having a PD width, but the index channel I Note that the optical detector has four separate photodetectors 20b, each detector having a PD width. In the embodiment shown in FIG. 5, the width of the index strip 31 is six times that of the PD, while the width of the data strip is twice that of the PD.

  In a manner similar to that illustrated in FIGS. 1 and 3, the A and A ′ data channels, the B and B ′ data channels, and the I and I ′ index channels of FIG. A pair of analog signals A and A ′, B and B ′, and I and I ′ are operably connected to the channel B comparator 23 and the channel I comparator 25, respectively, to the comparators. . Comparators 21, 23, and 25 compare each analog signal pair provided thereto by a single channel photodetector 48 to produce digital output signals 22, 24, and 26, as shown in FIG. From there.

  Referring now to FIG. 6, it can be seen that channel A comparator 21 compares the analog signals delivered by data channels A and A 'to provide a digital output signal 22. This output signal 22 is for channels A and A ′ where the code scale 30 moves over a single track photodetector 48 and the light emitted by the illuminant is located along a common axis 47. A series of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. Similarly, the channel B comparator 23 provides a digital output signal 24 by comparing the analog signals delivered by the data channels B and B '. This output signal 24 is for channels B and B ′ in which the code scale 30 moves over a single track photodetector 48 and the light emitted by the light emitters is located along a common axis 47. A series of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. As shown in FIG. 6, the output signals 22 and 24 are approximately 90 degrees out of phase with each other. Channel I comparator 25 provides a digital output signal 26 by comparing the analog signals delivered by index channels I and I '. This output signal 26 is an index output pulse that is considerably wider than the data output pulses 22 and 24 provided by the comparators 21 and 23 for the channels A and B, and is approximately 360 with respect to the width of the data output pulses 22 and 24. Have a width of degrees.

  The illuminator, single track photodetector 48 and code scale 30 of the embodiment of FIG. 5 includes an encoder 20 that is approximately 100 lines / inch (LPI), approximately 150 LPI, approximately 200 LPI, approximately 250 LPI, and / or approximately 300 LPI. Note that they can be tailored to provide a resolution greater than.

  Referring to FIG. 7, yet another embodiment of the reflective optical encoder 10 is shown. In this embodiment, a single track photodetector 48 is attached or mounted on the top surface of the substrate (not shown in FIG. 7). A light emitter (also not shown) is also attached or attached to the top surface, and in one aspect, is configured to emit light therefrom. The single track photodetector 48 has a common axis 47. A plurality of alternating sequences of pairs of A and B data channel photodetectors and A ′ and B ′ data channel photodetectors 24, disposed at opposite ends 43 and 45 of a single track photodetector 48 The two index channel I photodetectors 20b and the common axis 47 are arranged along the direction parallel to the data channel photodetector 24. A single index channel I ′ photodetector 20 a having a major axis that is not along is arranged along a common axis 47. Each pair of A and A 'and B and B' data channel photodetectors 24 are arranged 90 degrees out of phase with each other. The code scale 30 has index strips and data strips 31 and 33. This code scale is configured to move forward and / or backward along axis 49, depending on the particular application at hand. The axis 49 of the code scale 30 is at least approximately coincident and parallel to the corresponding axis 45 of the single track photodetector 48. The code scale 30 is single tracked so that at least a portion of the light emitted from the light emitter is reflected from the code scale 30 toward the data and index channel photodetectors 24, 20a and 20b. Arranged and configured to operate with photodetector 48.

  As further shown in the embodiment of FIG. 7, each of the data channel photodetectors A, A ′, B and B ′ (24) has a first width equal to about “PD”; On the other hand, the index channel I photodetector 20b has a width approximately equal to four times PD. The width of the index channel I 'photodetector 20a is approximately equal to one times PD.

  As further shown in the embodiment of FIG. 7, the height H of the index channel photodetector I (20b) is the height of the individual data channel photodetectors A, A ′, B and B ′. It is different from h. As shown in FIG. 7, the height H of the index channel I photodetector 20b is equal to about 1.5 times h, while the height of the index channel I ′ photodetector 20a is H is approximately 0.4 times h. In the embodiment shown in FIG. 7, the index channel I ′ photodetector comprises one separate photodetector 20a, but the index channel I photodetector 20b comprises two separate photodetectors 20a. Note that with a photodetector 20b, the width of each photodetector is about 4 and 1 times the PD, respectively. In the embodiment shown in FIG. 7, the width of the index strip 31 is six times that of the PD, while the width of the data strip is twice that of the PD.

  In a manner similar to that illustrated in FIGS. 1 and 3, the A and A ′ data channels, B and B ′ data channels, and I and I ′ index channels of FIG. A pair of analog signals A and A ′, B and B ′, and I and I ′ are operably connected to the channel B comparator 23 and the channel I comparator 25, respectively, to the comparators. . Comparators 21, 23, and 25 compare each analog signal pair provided thereto by a single channel photodetector 48 and, as shown in FIG. 8, digital output signals 22, 24, and 26, respectively. From there.

  Referring now to FIG. 8, it can be seen that channel A comparator 21 compares the analog signals delivered by data channels A and A 'to provide a digital output signal 22. This output signal 22 is for channels A and A ′ where the code scale 30 moves over a single track photodetector 48 and the light emitted by the illuminant is located along a common axis 47. A series of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. Similarly, the channel B comparator 23 provides a digital output signal 24 by comparing the analog signals delivered by the data channels B and B '. This output signal 24 is for channels B and B ′ in which the code scale 30 moves over a single track photodetector 48 and the light emitted by the light emitters is located along a common axis 47. A series of output pulses corresponding to the detection of light reflected from the data strip 33 on the code scale 30 when sequentially reflected to the photodetector. As shown in FIG. 8, the output signals 22 and 24 are approximately 90 degrees out of phase with each other. Channel I comparator 25 provides a digital output signal 26 by comparing the analog signals delivered by index channels I and I '. This output signal 26 is an index output pulse that is considerably wider than the data output pulses provided by the channel A and B comparators 21 and 23, and is approximately 360 degrees wide with respect to the width of the data output pulses 22 and 24. have.

  The light emitter, single track photodetector 48, and code scale 30 of the embodiment of FIG. 7 includes an encoder 20 that is approximately 100 lines / inch (LPI), approximately 150 LPI, approximately 200 LPI, approximately 250 LPI, and / or approximately 300 LPI. Note that they can be tailored to provide a resolution greater than.

  Various embodiments of the present invention solve several problems and have several advantages. In one embodiment, the single track photodetector 48 can reduce the size and cost of the encoder, thereby placing two data channels and one index channel along one track. It can be seen that a photodetector array corresponding to three channels can be placed on one integrated circuit die. In general, the integrated circuit in a reflective optical encoder is one of the most expensive components in a reflective optical encoder. Since the installation area and size can be reduced by the single track configuration disclosed in the present application, a small encoder with high resolution can be made. Furthermore, the area and code scale where light is spread by the light emitter can be made smaller. The reason is that the surface area of the data channel and index channel photodetectors can be reduced using the single track photodetector disclosed herein. Sensitivity to radial misalignment between the code scale and the photodetector is reduced because only one detector track is used. As a result, misalignment between the code wheel and the photodetector is reduced, and manufacturing and assembly costs are reduced because no special equipment is required to align the code scale with the photodetector. Is done. In some embodiments, it is not necessary in the prior art to use additional circuitry to increase the current output or to perform complicated logic operations to generate an output signal for the index channel. Complicated electronic circuits can be omitted. Various embodiments of the reflective optical encoder can not only achieve much higher resolution than before, but also reduce the size and footprint of the encoder. These various embodiments are relatively simple and easy to implement and can use smaller light emitting areas than before, resulting in smaller packages, code wheel and photodetector photo. Reduce the possibility of misalignment in the diode array, reduce die and assembly costs, use conventional simple electronics, and eliminate the need for circuit redesign . Further, in some embodiments, index channels I and I ′ do not share photodiodes with data channels A, A ′, B, and B ′, so various index pulse widths are based on the particular application at hand. Can occur.

  Methods for making the various components, devices and systems described herein are within the scope of the present invention. As an example, a method for making a reflective optical encoder is provided. The method includes providing a substrate having an upper surface, attaching or mounting a light emitter to the upper surface, a common axis and a direction of movement associated with the substrate, and A and B along the common axis. Single track light with a plurality of alternating sequences of pairs of data channel photodetectors and A ′ and B ′ data channel photodetectors and at least one pair of index channel I and I ′ photodetectors Attaching or mounting the detector to the top surface and positioning and operably positioning the code scale relative to the single track photodetector include A and A ′, B and B ′. And I and I ′ photodetectors are arranged 90 degrees out of phase with each other, and the code scale has an index and a data strip, and the code scale is common Moves along the at least a portion of the emitted light is reflected toward the code scale photodetector data channel and index channel from the light emitter. Such a method has a first width for each data channel photodetector and a first width for at least one of the index channel I photodetector and the index channel I ′ photodetector. Can be further provided to provide a second width of about 1.5, 2, 3 or 4 times or more.

  In addition to the previously disclosed embodiments, various embodiments are possible. For example, a transmissive optical encoder with a single track or other mechanism of the above-described embodiment is particularly conceivable.

  The embodiments described above are not intended to limit the scope of the invention, but should be considered as examples of the invention. In addition to the foregoing embodiments of the present invention, it will be appreciated that there are other embodiments of the present invention upon review of the detailed description and the accompanying drawings. Accordingly, many combinations, substitutions, changes and modifications of the above-described embodiments of the invention not explicitly described herein are intended to be included within the scope of the present invention.

Claims (27)

A substrate having an upper surface;
A light emitter attached or attached to the top surface and configured to emit light therefrom;
A plurality of alternating sequences of pairs of A and B data channel photodetectors and A ′ and B ′ data channel photodetectors along the common axis, and at least a pair of index channels I And a single-track photodetector mounted on or attached to the upper surface, wherein the photodetector for I ′ is disposed;
A reflective optical encoder comprising: an index and a data strip; and a code scale configured to move along the common axis,
The A and A ′ and B and B ′ photodetectors are arranged 90 degrees out of phase with each other, and are arranged and configured such that the code scale can operate with respect to the single track photodetector, A reflective optical encoder in which at least a portion of the light emitted from the light emitter is reflected from the code scale toward the data channel and index channel photodetectors.   Each of the data channel photodetectors has a first width, and at least one of the index channel I photodetector and the index channel I ′ photodetector is relative to the first width. The reflective optical encoder of claim 1 having a second width of about 1.5, about 2, about 3, or about 4 times or more.   Each of the data channel photodetectors has a first height, and at least one of the index channel I photodetector and the index channel I ′ photodetector is relative to the first height. The reflective optical encoder according to claim 1, having a second height of about 1.5 times or more.   Each data channel photodetector has a first height, and at least one of the index channel I photodetector and the index channel I ′ photodetector is at the first height. The reflective optical encoder according to claim 1, wherein the reflective optical encoder has a second height that is about twice or more.   Each data channel photodetector has a first height, and at least one of the index channel I photodetector and the index channel I ′ photodetector is at the first height. The reflective optical encoder according to claim 1, wherein the reflective optical encoder has a second height that is about three times or more.   Each of the data channel photodetectors has a first height, and one of the index channel I photodetector and the index channel I ′ photodetector is the first height and the second height. The reflective optical encoder according to claim 1, wherein the reflective optical encoder has a third height that is equal to or less than a height of.   The reflective optical encoder according to claim 1, wherein the third height of one of the index channel I photodetectors is about 0.9 times the first height.   A pair of reflective and non-reflective data strips on the code scale have a first width together, the index strip on the code scale has a second width, and the second The reflective optical encoder of claim 1, wherein the width of the reflective optical encoder is at least about 1.5 times the first width.   A pair of reflective and non-reflective data strips on the code scale has a first width, the index strip on the code scale has a second width, and the second width The reflective optical encoder of claim 1, wherein is at least about 2.5 times the first width.   A pair of reflective and non-reflective data strips on the code scale has a first width, the index strip on the code scale has a second width, and the second width The reflective optical encoder of claim 1, wherein is at least about 3.5 times the first width.   The reflective optical encoder according to claim 1, wherein at least one of the index channel I photodetector and the index channel I 'photodetector comprises at least two separate photodetectors.   Each of the data channel photodetectors has a first width, and at least one of the index channel I photodetector and the index channel I ′ photodetector is about 1.. 12. The reflective optical encoder of claim 11, having a second width of 5 or greater, and wherein the at least two separate photodetectors are separated by a distance of about the first width.   Each data channel photodetector has a first width, and at least one of the index channel I photodetector and the index channel I ′ photodetector is at least four adjacent discrete lights. The reflective optical encoder according to claim 1, further comprising a detector, wherein each of the separate photodetectors has the first width.   14. A reflective optical encoder according to claim 13, wherein the at least four adjacent separate photodetectors are located in the center of the single track photodetector.   The index channel I photodetector comprises the at least four adjacent discrete photodetectors, and the index channel I ′ photodetector is at least one of the two adjacent discrete photodetectors. 1 and a second pair, each of the separate photodetectors having the first width, and the first and second pairs of the first and second single-track photodetectors respectively. The reflective optical encoder according to claim 14, which is disposed at the second end.   2. The reflective optical encoder according to claim 1, wherein at least one of the index channel I photodetector and the index channel I ′ photodetector has a major axis disposed along a direction parallel to a common axis. .   At least one of the index channel I photodetector and the index channel I ′ photodetector is offset laterally from the data channel photodetector and is not along the common axis The reflective optical encoder according to claim 1.   Each of A and A ′ data channels, B and B ′ data channels, and I and I ′ index channels are operatively connected to channel A, channel B, and channel I comparators, respectively, to provide an analog signal A And A ′, B and B ′, and I and I ′ pairs, respectively, to the channel A, channel B, and channel I comparators, respectively.   Each of the comparators for channel A, channel B, and channel I is based on a comparison between pairs of analog signals A and A ′, B and B ′, and I and I ′ delivered to the comparator, 19. A reflective optical encoder according to claim 18, configured to provide digital high and low output signals therefrom.   The light emitter, the single track photodetector, and the code scale may be configured such that the encoder is approximately 100 lines / inch (LPI), approximately 200 lines / inch (LPI), approximately 250 lines / inch (LPI), The reflective optical encoder of claim 1, configured to provide a resolution greater than about 300 LPI, or about 400 lines / inch (LPI).   The reflective optical encoder of claim 1, further comprising a dome lens made of an optically transparent material.   And an optically opaque light barrier disposed between the light emitter and the single track photodetector, the light barrier configured to prevent stray light from entering the single track photodetector. The reflective optical encoder according to claim 1, wherein the reflective optical encoder is configured to prevent or prevent.   The reflective optical encoder according to claim 1, wherein the data channel photodetector and the index channel photodetector are arranged on one die.   The reflective optical encoder according to claim 1, wherein the substrate is a printed circuit board, and the lead frame is made of plastic or formed of a polymer. Providing a substrate having a top surface;
Attaching or attaching a light emitter to the upper surface;
A plurality of alternating sequences and index channel I of pairs of A and B data channel photodetectors and A ′ and B ′ data channel photodetectors along said common axis and having a common axis associated with them; And mounting or mounting a single-track photodetector having at least one pair of photodetectors for I ′ on the top surface;
Positioning and operably disposing a code scale relative to the single track photodetector, the method comprising:
The A and A ′, B and B ′ and I and I ′ photodetectors are arranged 90 degrees out of phase with each other, the code scale comprises an index and a data strip, and the code scale is the common axis And at least a portion of the light emitted from the light emitter is reflected from the code scale toward the data channel and index channel photodetectors.   Each of the data channel photodetectors has a first height, and at least one of the index channel I photodetector and the index channel I ′ photodetector is about 1 greater than the first height. 26. The method of claim 25, further comprising the step of having a second height that is five times or greater than about twice.   Providing the code scale with alternating pairs of light and dark reflective and non-reflective data strips, wherein the pair of data strips has a first width and the at least one code 26. The method of claim 25, wherein the strip has a second width and the ratio of the second and first width is one of about 1.5, about 2.5, and about 3.5.

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