CN115931015A

CN115931015A - Pixel unit design method of optical encoder

Info

Publication number: CN115931015A
Application number: CN202310057499.9A
Authority: CN
Inventors: 王晓曦; 邓仕杰; 高朕
Original assignee: Chuanzhou Semiconductor Technology Shanghai Co ltd
Current assignee: Chuanzhou Semiconductor Technology Shanghai Co ltd
Priority date: 2023-01-16
Filing date: 2023-01-16
Publication date: 2023-04-07

Abstract

The invention provides a pixel unit design method of an optical encoder.A receiving unit (2) used in the design consists of rectangular pixel units (4) and does not need to be additionally processed into a special shape; the used pixel unit (4) is a Photodiode (PD) generally, and photoelectric detector devices such as an Avalanche Photodiode (APD) and a Single Photon Avalanche Diode (SPAD) can be selected according to application conditions; the receiving unit (2) needs to be matched with scanning light spots (3) generated by other optical systems to generate periodic signals; when the device works, the scanning light spot (3) can relatively move along the scanning direction (1) and generates a periodic signal similar to a sine through the receiving unit (2); the invention can be used for receiving optical signals in optical encoder products and can also be used for measuring optical signals in grating ruler products.

Description

Pixel unit design method of optical encoder

Technical Field

The invention relates to a design method of a pixel unit of an optical encoder, which can be used for the measurement of the optical encoder and a grating ruler and belongs to the technical field of photoelectric detection.

Background

The photoelectric encoder is a sensor which converts the mechanical geometric displacement on an output shaft into pulse or digital quantity by photoelectric conversion. The sensor is most applied, the photoelectric encoder converts the geometric displacement of the rotating shaft into equal-width pulses for output through a photoelectric conversion technology, namely, the continuous displacement is discretized into the individual equal-size pulses, and the generated pulses correspond to the displacement sizes one by one, so that the smaller the displacement corresponding to one pulse is, the more accurate the displacement is, and the recorded pulse sum corresponds to the displacement sum. In general, an incremental photoelectric encoder outputs two pulse signals different by 90 ° and generates a Z pulse signal every rotation. The rotation direction can be conveniently judged by analyzing the phase relation among the pulse signals; the Z phase may be used to reduce the accumulated error. It follows that in the photoelectric encoder product, the receiving picture element is an indispensable part.

In the field of photoelectric detection technology, common photodetectors used in a receiving pixel include a Photodiode (photo Diode), an Avalanche Photodiode (Avalanche Photon Diode), a Single Photon Avalanche Photodiode (Single Photon Avalanche Diode), and the like. With the rise of semiconductor production technology and integrated circuit design technology in this century, the production and manufacturing technology of these devices has advanced greatly. Compared with some photoelectric sensing devices, such as photomultiplier tubes, which are mainstream in the last century, the photoelectric sensing devices have the advantages of small size, light weight, good thermal stability, convenience in use and the like. Photodiodes have been widely used in the field of photoelectric encoder products. In order to generate a sinusoidal signal, after the photodiode generates a photocurrent, decoding work needs to be performed at a system level; or the photodiodes are finely divided and then the signals generated by these diodes are subjected to signal processing using a high level to provide a high resolution periodic signal to the user. However, as the price of ADCs in integrated circuits increases rapidly with increasing resolution, there is a certain impact on the cost during manufacturing.

In order to reduce the dependence on a post-filtering circuit, researchers at home and abroad research and design the shapes of photodiodes or other types of detectors in a sensing pixel under the existing production process to optimize the performance and the cost of the whole product. Xiong Wenshuo, xiong Wenkai, etc. published a design scheme of matching a reticle pattern, a code wheel pattern and a pixel array in 2015 (CN 204831337), in which the reticle is designed to have slits with various long axis directions, the code wheel uses a plurality of code channels following the gray code design scheme, the pixel array uses a plurality of pixel units, the size and arrangement in the spot scanning direction and the vertical scanning direction are modulated to improve the system accuracy, and since the central portion of the pixel array is not continuous, the reticle needs to be accurately aligned with the pixel array during installation, which is inconvenient in production and manufacture; an iC-Haus GmbH discloses a pixel shape design scheme (DE 10 2014 112 459 Optischer positionencoder), which is characterized in that a metal mask with a special open pore shape is designed for an arrow-shaped pixel unit, so that a scanning spot formed by an LED and a code disc generates a half-period sine signal when passing through the pixel unit, and various signals such as sine and cosine can be obtained through subsequent circuit processing, but the metal mask processing is performed on the pixel unit, so that the process cost is provided on one hand, and the yield of products can be reduced due to randomly introduced scratches and the like when the surface of the pixel unit is processed on the other hand; dr. Johannes Heidenhain GmbH also proposed a design scheme of pixel unit shape (DE 0541829 Vorrichttung zur Erzeugung oberwellen freier periodiser Signal), when scanning light spot passes through a single pixel, a half-cycle sinusoidal signal can be generated, which has the disadvantage that the pixel is directly cut into high-grade geometric shapes, a series of process problems such as edge breakage and the like can be brought, and the pixel itself is damaged.

In order to solve the problems, the invention discloses a method for designing a receiving pixel of a linear optical encoder for generating a sine-like waveform signal, which can be used in the fields of optical encoders, grating ruler measurement and the like. The present invention uses modulation of the pixel array in the vertical scan direction to generate a sine-like waveform signal. The structure is simple, the process is simple: the pixels in the invention are all rectangular, so that the problems of cost, yield, process and the like caused by cutting the pixels by using a high-grade complex graph and covering the pixels by using a metal mask are avoided.

Disclosure of Invention

The invention aims to provide a pixel unit design method of an optical encoder for generating a sine-like waveform signal, which mainly considers the following elements:

1. a scanning spot (3) movable or scannable along a scanning direction (1);

2. the scanning light spot (3) can be generated on the plane of the receiving unit (2) by a light source and a code disc, and is characterized in that the optical power density in the scanning light spot area is consistent;

3. the receiving unit (2) is composed of a plurality of pixel units (4) and can receive the optical signals in the scanning light spots and convert the optical signals into electric signals to be output;

4. the pixel unit (4) can be one of a photodiode, an avalanche photodiode or a single photon avalanche diode. The pixel cells (4) are divided in the receiving unit (2) into two different regions: a forward signal area (5) and a reverse signal area (6), and each pixel unit in each area has a different length but an equal width.

The invention realizes the functions according to the following principles:

when the scanning light spot (3) moves along the scanning direction (1), the scanning light spot firstly passes through a forward signal area (5) in the receiving unit (2), and an electric signal is generated by the overlapped area of the scanning light spot (3) and each pixel unit (4). Since the increment of the overlapping area is not completely equally linear with the increase of the scanning stroke, when the scanning light spot (3) scans 3 pixel units (7), (8) and (9) in the forward signal area (5), a half-period sine-like signal is generated; when the scanning light spot (3) continues to scan until the centers of the two areas, the signal intensity returns to zero; when the scanning spot (3) continues to advance, the reverse signal region (6) continues to generate the second half of the sinusoidal-like period signal. During the advance of the scanning spot (3), only the pixel elements of the overlapping area will contribute to the generated signal.

The scanning direction (1) in the system may be any of a linear direction or a rotational direction centered on a certain point.

The receiving unit (2) in the system is formed by symmetrically distributing a plurality of pixel units (4) with the same moving direction size but different orthogonal direction sizes. The size occupied by the pixel units in the motion direction is P, the size occupied by a single pixel unit is P/N, wherein N is the number of the pixel units in the receiving unit (2), and theoretically, the more the number of the pixel units, the higher the signal precision.

The scanning spot (3) in the system is generated by other optical systems on the plane of the pixel cell (4). The size of the receiving unit (2) in the moving direction is 2 pixels to ensure that the receiving unit (2) just covers two or more pixel units at the central position when moving to the P/2 position, and ensure that the whole receiving unit (2) outputs a '0' signal at the moment.

Preferably, the pixels (7) (8) (9) are not equal in size in the vertical direction, and the size of these pixels is modulated.

The pixel cells (4) in the system are typically formed by photodiodes, preferably also photoelectric sensing devices such as avalanche photodiodes, single photon avalanche diodes, etc. The production process includes, but is not limited to, modern semiconductor processes such as Complementary Metal Oxide Semiconductor (CMOS), and the topography includes, but is not limited to, rectangular, willow-leaf, fan-shaped, etc.

When the width of the scanning light spot (2) is 2 pixel units (4), the size proportion of each pixel in the direction perpendicular to the scanning direction along the scanning direction follows the following formula:

wherein L is _n Is the relative length of the nth pixel unit, N is the number of pixel units in a receiving unit, where N is usually an even number and L ₀ ＝0。

Drawings

Fig. 1 is a schematic diagram of a system configuration at a receiving end of an optical encoder for generating a sine-like waveform signal. The receiving-end system is mainly composed of a scanning spot (3) and a receiving unit (2), wherein the receiving unit (2) is composed of a plurality of pixel units (4) which are equal in size in the scanning direction (1) but not only in size in the vertical direction. When the system works, the light in the scanning light spots (3) is uniform, the receiving unit (2) is scanned along the scanning direction (1), and the pixel units (4) have a specific shape distribution design, so that the system can generate optical signals with similar sine waveforms. The width of the scanning spot (3) can be adjusted with the system precision, and the width of the scanning spot (3) is 2 pixel units (4).

Fig. 2 is a detailed configuration diagram of the receiving unit (2). The receiving unit (2) mainly comprises a plurality of pixel units (4); the pixel units (4) are divided into two groups in detail, wherein one group is a forward signal area (5) responsible for outputting forward signals, and the other group is a reverse signal area (6) responsible for outputting reverse signals. When the scanning light spot (3) scans along the scanning direction (1), a pixel unit (7) generating a forward signal is scanned in advance, and the forward signal starts to be generated; when scanning to the middle of the forward signal area (5) and the reverse signal area (6), two pixel units (9) and (10) covered by the scanning light spot have equal areas and receive equal light energy, so that two signals with equal sizes and opposite directions are generated to be mutually cancelled, and a signal '0' with 180-degree phase is output, and when the scanning light spot (3) continues to scan and enters the reverse signal area (6), the receiving unit (2) starts to output a reverse signal corresponding to the signal in the second half period of sine.

FIG. 3 is a diagram of a pixel cell design method of an optical encoder for generating a sinusoidal-like waveform signal. In the design example, the width of the default scanning spot (3) is 2 pixel units, the number N =6 of the pixel units (4) in the receiving unit (2) is that scanning is started from the pixel unit (4) with the number a; in order to realize the output of the sine-like waveform signal, the length of each pixel unit (4) needs to be modulated, and the length proportion of each numbered pixel unit is shown in a chart.

Fig. 4 is a diagram of fig. 3, which is a diagram of a sinusoidal-like waveform signal generated by the receiving unit, and illustrates an implementation effect of the first embodiment.

FIG. 5 is a diagram of a second embodiment of a pixel cell design method for an optical encoder for generating a sinusoidal-like waveform signal. In the design example, the width of the default scanning spot (3) is 2 pixel units, and the number of the pixel units (4) in the receiving unit (2) is N =10; the scanning light spot (2) scans along the scanning direction (1), and in order to realize the output of the sine-like waveform signal, the length proportion of each pixel unit (4) needs to be modulated.

Fig. 6 is a diagram of fig. 5, which is a diagram of a sinusoidal-like waveform signal generated by the receiving unit, and additionally illustrates the implementation effect of the second embodiment.

Detailed Description

The first embodiment is as follows:

fig. 3 shows an embodiment of a pixel cell design method of an optical encoder for generating sinusoidal waveform signals, wherein the receiving unit is composed of 6 photodiodes with the same scanning direction size but different vertical scanning direction sizes. Since the size of the receiving unit needs to be modulated to generate the sine waveform signal, the size of the photodiode needs to be calculated according to the following formula:

the size ratio of each photodiode in the vertical scanning direction can be obtained by calculation: a =0.707106, b =0.292893, c =0.414213, d =0.414213, e =0.292893, f =0.707106, in the present embodiment, the size of the photodiode along the scanning direction is 10um, the maximum size perpendicular to the scanning direction can be made to 100um, and the size a =70.7106um, b =29.2893um, c =41.4213um, d =41.4213um, e =29.2893um, f =70.7106um of each photodiode perpendicular to the scanning direction is calculated by proportion. When the scanning spot (2) is scanned across the photodiode a, the area of overlap between them increases linearly with the scanning motion, with slope ka =70.7106/D; where D is the width of a single photodiode along the scanning direction, in this embodiment, D =10um, ka =7.07106; when the scanning light spot (2) scans the photodiode b, the overlapped area between the scanning light spot and the photodiode b is linearly increased along with the scanning motion, and the overlapped area with the photodiode a is kept unchanged, so that the change slope kb of the generated signal along with the scanning motion is =2.92893; when the scanning light spot (2) scans the photodiode c, the overlapped area between the scanning light spot (2) and the photodiode a is linearly increased along with the scanning motion, but the overlapped area between the scanning light spot (2) and the photodiode a is linearly decreased, the change slope of the generated signal along with the scanning motion is kc =41.4213/D-70.7106/D, and kc = -2.92893 is calculated; when the scanning light spot (2) scans the photodiode D, the overlapped area between the scanning light spot and the photodiode D is linearly increased along with the scanning motion, but the overlapped area with the photodiode b is linearly reduced, the reverse signal output by the photodiode D is comprehensively considered, and the change slope kd = -41.4213/D-29.28983/D = -7.07106 of the generated signal along with the scanning motion is generated; when the scanning spot (2) scans the photodiode e, the overlapped area between the scanning spot and the photodiode e is linearly increased along with the scanning motion, but the overlapped area between the scanning spot and the photodiode c is linearly reduced along with the scanning motion, and the change slope of the generated signal along with the scanning motion is ke = -29.4213/D-41.4213/D = -7.07106; when the scanning spot (2) scans across the photodiode f, the overlapping area between the scanning spot and the photodiode increases linearly with the scanning motion, but the overlapping area between the scanning spot and the photodiode D decreases linearly with the scanning motion, and the change slope kf of the generated signal with the scanning motion is = -70.7106/D- (-41.4213/D) = -2.92893; when the scanning light spot (2) scans across the photodiode f and continues to advance by one pixel unit width D along the scanning direction, the overlapping area between the scanning light spot (2) and the photodiode f is kept unchanged along with the scanning motion, but the overlapping area between the scanning light spot and the photodiode e is linearly reduced along with the scanning motion, and the change slope kf' =29.2893/D =2.92893 of the generated signal along with the scanning motion; when the scanning light spot (2) scans the distance D-2D behind the photodiode f, the area of the overlap between the photodiode f and the scanning light spot (2) is linearly reduced along with the scanning motion, but no photodiode receives signals in the space behind the photodiode f, and the change slope kf "=70.7106/D =7.07106 of the generated signals along with the scanning motion. The change of the signal along with the scanning motion of the scanning light spot (2) is wholly shown in figure 4, and the generation of the sine-like waveform signal is wholly realized. In addition, the shaping and filtering processing can be carried out by matching with a back-end circuit, so that the whole waveform is more consistent with a sine waveform or is transformed into a cosine waveform and the like.

Example two:

fig. 5 shows an embodiment of a pixel cell design method of an optical encoder for generating sinusoidal waveform signals, wherein the receiving unit is composed of 10 photodiodes with the same scanning direction size but different vertical scanning direction sizes. Since the size of the receiving unit needs to be modulated to generate the sine waveform signal, the size of the photodiode needs to be calculated according to the following formula:

the size proportion of each photodiode in the vertical scanning direction can be obtained through calculation: a =0.5, b =0.366025, c =0.633975, d =0.232050, e =0.267950, f =0.267950, g =0.232050, h =0.633975, i =0.366025, j =0.5, in this embodiment, the dimension of the photodiode in the scanning direction is 10um, the maximum dimension perpendicular to the scanning direction can be made to 100um, and the dimension of each photodiode in the direction perpendicular to the scanning direction is calculated by scaling a =50um, b =36.6025um, c =63.3um, d =41.4213um, e =26.7950um, f 26.7950um, g =23.2050um, h =63.3975, i = 36.60250um, j =50um. When the scanning spot (2) is swept over the photodiode a, the area of overlap between them increases linearly with the scanning motion, with a slope ka =50/D; where D is the width of a single photodiode along the scanning direction, in this embodiment, D =10um, then ka =5; when the scanning light spot (2) scans the photodiode b, the overlapped area between the scanning light spot and the photodiode b is linearly increased along with the scanning motion, and the overlapped area with the photodiode a is kept unchanged, so that the change slope kb of the generated signal along with the scanning motion is =3.66025; when the scanning light spot (2) scans the photodiode c, the overlapping area between the scanning light spot (2) and the photodiode a is linearly increased along with the scanning motion, but the overlapping area between the scanning light spot (2) and the photodiode a is linearly decreased, the change slope of the generated signal along with the scanning motion is kc =63.3975/D-50/D, and kc =1.33975 is calculated; when the scanning light spot (2) scans the photodiode D, the overlapped area between the scanning light spot and the photodiode D is linearly increased along with the scanning motion, but the overlapped area with the photodiode b is linearly decreased, and the change slope kd =23.2050/D-36.6025/D = -13.3975 of the generated signal along with the scanning motion; when the scanning spot (2) scans the photodiode e, the overlapped area between the scanning spot and the photodiode e is linearly increased along with the scanning motion, but the overlapped area between the scanning spot and the photodiode c is linearly reduced along with the scanning motion, and the change slope of the generated signal along with the scanning motion is ke =26.7950/D-63.3975/D = -3.66025; when the scanning light spot (2) scans the photodiode f, the overlapped area between the scanning light spot and the photodiode increases linearly with the scanning motion, but the overlapped area between the scanning light spot and the photodiode D decreases linearly with the scanning motion, and the change slope kf = -26.7950/D-23.2050/D = -5 of the generated signal along with the scanning motion is comprehensively considered; when the scanning light spots (2) sweep over the photodiodes g, the overlapped area between the photodiodes g and the photodiodes e linearly increases along with the scanning motion, but the overlapped area between the photodiodes e and the scanning light spots linearly decreases along with the scanning motion, and the change slope kg of the generated signals along with the scanning motion is comprehensively considered to be-23.205/D-26.7950/D = -5; when the scanning light spot (2) scans the photodiode h, the overlapped area between the scanning light spot and the photodiode increases linearly with the scanning motion, but the overlapped area between the scanning light spot and the photodiode f decreases linearly with the scanning motion, and the change slope kh = -63.3975/D- (-26.7950/D) = -3.66025 of the signal generated along with the scanning motion is comprehensively considered; when the scanning light spot (2) scans the photodiode i, the overlapped area between the scanning light spot and the photodiode i is linearly increased along with the scanning motion, but the overlapped area between the scanning light spot and the photodiode g is linearly reduced along with the scanning motion, and the slope ki = -36.6025/D- (-26.7950/D) = -1.33975 of the change of the signal along with the scanning motion is comprehensively considered; when the scanning light spot (2) scans the photodiode j, the overlapped area between the scanning light spot and the photodiode j is linearly increased along with the scanning motion, but the overlapped area between the scanning light spot and the photodiode h is linearly reduced along with the scanning motion, and the change slope kj = -50/D- (-63.3975/D) =1.33975 of the signal along with the scanning motion is comprehensively considered; when the scanning light spot (2) scans the photodiode j and continues to advance by one pixel unit width D along the scanning direction, the overlapping area between the scanning light spot (2) and the photodiode j is kept unchanged along with the scanning motion, but the overlapping area between the scanning light spot and the photodiode i is linearly reduced along with the scanning motion, and the change slope kj' =36.6025/D =3.66025 of the generated signal along with the scanning motion; when the scanning light spot (2) scans the distance D-2D behind the photodiode j, the overlapping area between the photodiode j and the scanning light spot (2) is linearly reduced along with the scanning motion, but no photodiode receives signals in the space behind the photodiode j, and the change slope kj' =50/D =5 of the generated signals along with the scanning motion. The change of the signal along with the scanning motion of the scanning light spot (2) is wholly shown in figure 6, and the generation of the sine-like waveform signal is wholly realized. In addition, the shaping and filtering processing can be carried out by matching with a back-end circuit, so that the whole body better conforms to sine waveforms or is transformed into cosine waveforms and the like.

Claims

1. A method for designing a pixel unit of an optical encoder, comprising: the receiving end of the optical encoder consists of a scanning light spot (3) moving along a scanning direction (1) and a receiving unit (2); in the system, scanning light spots (3) are generated on a plane where the receiving unit (2) is located by other optical systems, and the inner part of the system has uniform optical power density distribution; when the scanning light spot (3) moves along the scanning direction (1), the scanning light spot passes through the receiving unit (2); the receiving unit (2) is composed of a plurality of pixel units (4), and the pixel units can receive optical signals and convert the received optical power into current or voltage signals for output; when the scanning light spot (3) is projected to the pixel unit (4), a signal which is in equal proportion to the overlapped area of the scanning light spot (3) and the pixel unit (4) is generated; the pixel cells (4) are generally equal in size in the scanning direction, but may be modulated in size in a direction perpendicular to the scanning direction in accordance with a sinusoidal signal waveform to output a signal resembling a sinusoidal waveform.

2. A method as claimed in claim 1, wherein the method comprises: scanning light spots need to be considered, and the light spots can be generated by an LED light source matched with a collimating lens, or can be generated by a vertical cavity surface semiconductor laser array matched with a light homogenizing sheet or a micro-lens array. When the light beams generated by the two modes pass through a structure with a rectangular opening, such as a code disc of an optical encoder, the generated light spot is a scanning light spot with uniform optical power density distribution; the scanning light spot has a certain size in the scanning direction, the size of 1 pixel unit (4) in the scanning direction is taken as a basic unit in the patent, and the size of the scanning light spot (3) is required to be 2 times that of the pixel unit (4) in the scanning direction. The size of the scanning light spot in the direction perpendicular to the scanning direction is required to be larger than that of any pixel unit (4), and the fact that each pixel unit receives light signals filling the whole pixel unit at the opportunity in the scanning process is guaranteed.

3. A method as claimed in claim 1, wherein the method comprises: the device has a receiving unit (2) which is located in the scanning direction (1) or in the same plane and at the same horizontal position as the scanning spot (3). The receiving unit (2) is composed of a plurality of pixel units (4) which are arranged on the same horizontal position in a mutually contact mode; these pixel cells (4) are photodetector devices, in particular, including but not limited to photodiodes, avalanche photodiodes, single photon avalanche photodiodes, etc.; when the pixel units (4) form the receiving unit (2), the pixel units are generally rectangular, and can be adjusted to be in various geometrical structures such as a triangle, a willow leaf shape, a fan shape and the like. These pixel cells (4) can be further subdivided into two regions: a forward signal area (5) and a reverse signal area (6), and the final output signal is the sum of the signals output by the pixel units of the two areas.

4. A method as claimed in claim 1, wherein the method comprises: the size of each pixel unit (4) forming the receiving unit (2) in the vertical scanning direction needs to be modulated, and the distribution rule of the size along the scanning direction (1) follows the following steps:

wherein L is _n Showing the size ratio of the nth pixel unit in the vertical scanning direction, wherein N represents the number of the pixel units (4) in the receiving unit (2), is an even number and is L ₀ =0; after the proportion of each pixel unit (4) is solved through the proportional relation, a dimension parameter A can be determined by combining the actual production and manufacturing process, and the dimension parameter A is multiplied by L _n To determine the size of individual pixel elements in the system; in actual production manufacturing, a may be any one of 100um,50um,20um, 10um; when the scanning light spot (3) scans the receiving unit (2), the scanning light spot is respectively overlapped with the pixel units (4) with different sizes to generate signals. These signals are superposed with each other, and finally, the output of the sine-like waveform signal is generated.

5. The design method of pixel unit of optical encoder as claimed in claim 2, wherein the opening on the code disc of the optical encoder can be replaced by other shapes according to the actual measurement requirement, such as: fan-shaped, Z-shaped, etc., so as to change the shape of the scanning spot (3); when the shape of the scanning spot (3) is changed, the shape of the receiving unit (2) can be adjusted to the scanning spot (3) to ensure the accuracy of the generated signal, for example: the shape of the receiving unit (2) is changed to the same shape as the scanning spot (3), but reduced by a specific scaling factor; or the shape of the scanning spot (3) is split and recombined into another shape, and the shape is used as the shape of the receiving unit (2) after the shape is reduced according to a specific scale factor.

6. A method as claimed in claim 3, wherein in special cases, for example, the pixel units (4) are not allowed to be arranged adjacently by the existing process, the arrangement can be adjusted, and under the premise that each pixel unit (4) has the opportunity to receive the optical signal filling the whole pixel unit (4), for example, the positions of the existing pixel units (4) in the scanning direction (1) are not changed, and the pixel units (4) are arranged in a staggered manner in the direction perpendicular to the scanning direction (1), thereby avoiding mutual contact and overcoming the inconvenience in the process.