JP4672542B2 - Photoelectric encoder and electronic equipment - Google Patents

Description

  The present invention relates to a photoelectric encoder and an electronic device, and more particularly to a photoelectric encoder that detects a position, a moving speed, a moving direction, and the like of a moving body using a light receiving element, and an electronic device using the photoelectric encoder.

  2. Description of the Related Art Conventionally, as a photoelectric encoder, a plurality of slits X1, X2 are arranged between a light emitting element and a light receiving element arranged to face each other at a constant pitch P in the moving direction as schematically shown in the upper part of FIG. ,... And the slit width is ½ pitch (that is, P / 2). In the light transmission type, the slits X1, X2,... Correspond to a portion where light is incident on the light receiving element (this is referred to as “light-on portion”), and a plate material (moving) between the slits X1, X2,. The portions Y1, Y2,... Made of the body material correspond to portions where light is not incident on the light receiving element (this is referred to as “light-off portion”).

  For example, as described in Patent Document 1 (Japanese Patent No. 3256109), as shown in the middle part of FIG. 26, the width of each of the slits X1, X2,. Four photodiodes PD1, PD2, PD3, and PD4 that are half (that is, P / 4) are arranged side by side without a gap, and four signals (in order A +) output by the photodiodes PD1, PD2, PD3, and PD4 are arranged. , B-, A-, B +). Of these four signals, A + and A- and B + and B- are respectively compared by a comparator to obtain two output signals having a phase difference of 90 [deg.]. The two output signals having a phase difference of 90 ° are the same as the slit operation cycle of the moving body.

  Further, as described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2001-99684), as shown in the lower part of FIG. 26, the slit widths along the arrangement direction of the slits X 1, X 2,. On the other hand, four photodiodes 13a, 13b, 13c, and 13d having the same width (that is, P / 2) are arranged at 3/4 pitch (that is, 3P / 4), and the photodiodes 13a, 13b, Four signals (A +, B +, A−, and B− in order) output by 13c and 13d are read. Of these four signals, A + and A- and B + and B- are respectively compared by a comparator to obtain two output signals having a phase difference of 90 [deg.]. The two output signals having a phase difference of 90 ° are the same as the slit operation cycle of the moving body.

  In any of the above conventional photoelectric encoders, an output signal can be obtained only in the same cycle as the moving frequency of the moving body, and minute frequency fluctuations cannot be read. In any of the photoelectric encoders, obtaining a high-frequency signal from the moving frequency of the moving body can improve the resolution during use, leading to improved characteristics.

  Although it is possible to narrow the slit width of the moving body and increase the frequency of the output signal on the light receiving side with the prior art, if the slit width is narrowed, the amount of input light cannot be secured and the SN is reduced. In addition to being connected, there is also a problem that light sneak is considered, and an offset between signals becomes large, resulting in deterioration of characteristics.

From the above, a method for obtaining a higher frequency signal while securing the slit width of the moving body is required.
Japanese Patent No. 3256109 JP 2001-99684 A

  Accordingly, an object of the present invention is to provide a photoelectric encoder capable of obtaining an output signal having a frequency higher than the moving frequency of the moving body while ensuring the slit width of the moving body so as not to deteriorate the characteristics. .

  Another object of the present invention is to provide an electronic apparatus provided with the photoelectric encoder.

In order to solve the above problems, the photoelectric encoder of the present invention is
A light emitting element;
A plurality of light receiving elements arranged in one direction in a region where the light from the light emitting element can reach,
A movable body having alternately a light-on portion and a light-off portion that create a state where the light is incident on the light-receiving element and a state where the light is not incident on the light-receiving element at a predetermined position corresponding to each light-receiving element is predetermined. The output of each light receiving element takes a value corresponding to whether light from the light emitting element is incident or not incident on the light receiving element,
The width of each light receiving element in the one direction is equal to or less than ¼ of an input pitch length which is a sum of lengths of the pair of the light on part and the light off part adjacent to the moving body along the one direction. And substantially the same,
The plurality of light receiving elements are divided into a plurality of light receiving element groups each composed of 16 light receiving elements having different phase relationships with respect to a modulation period of incident light due to movement of the moving body,
The plurality of light receiving element groups have 16 sets in which light receiving elements having the same phase relationship with respect to the modulation period of incident light due to the movement of the moving body are combined one by one from the respective light receiving element groups,
An adder for adding and outputting signals of a plurality of light receiving elements of the same set for each set of light receiving elements having the same phase relationship ;
With
The light receiving element has the same dimensions in the one direction, and has a light on part corresponding region corresponding to the light on part and a light off part corresponding region corresponding to the light off part at a common constant pitch. Are arranged one by one,
The light-receiving elements arranged in the light-on part corresponding region and the light-receiving elements arranged in the light-off part corresponding region have a one-to-one correspondence with the one-to-one correspondence in the arrangement order in the one direction. A comparison unit that takes the difference between the outputs of the element pairs added by the addition unit;
A logic operation unit that performs an operation on a logical value represented by the difference signal obtained by the comparison unit and creates an output signal having a frequency different from the moving frequency ;
The comparison unit includes amplifiers corresponding to the light receiving element pairs,
The plurality of amplifiers are arranged side by side in the one direction along a row formed by the plurality of light receiving elements,
With respect to the one direction, the center position of the column formed by the plurality of light receiving elements and the center position of the column formed by the plurality of amplifiers are the same.

  Here, the “moving frequency” means the number of times the light-on part of the moving body passes through a position corresponding to a certain light receiving element within a unit time. When a plurality of light-on parts are provided on the moving body, when counting the moving frequency, the individual light-on parts are not distinguished, and any light-on part passes is counted once. Shall.

According to the photoelectric encoder having the above-described configuration, the light-on portion and the light-off portion of the moving body have predetermined moving frequencies at predetermined positions corresponding to the light receiving elements along one direction in which the light receiving elements are arranged. Pass alternately with. When the light-on part and the light-off part pass through the position, the light-on part and the light-off part respectively create a state where light from the light-emitting element is incident on the light-receiving element and a state where it is not incident. As the light-on part and the light-off part of the moving body sequentially pass through the positions corresponding to the plurality of light receiving elements, the output values of the plurality of light receiving elements change sequentially. The plurality of light receiving element groups have 16 sets in which light receiving elements having the same phase relationship with respect to the modulation period of incident light due to movement of the moving body are combined one by one from each light receiving element group, For each set of a plurality of light receiving elements having the same phase relationship, the signals of the plurality of light receiving elements in the same set are added by the adder and output. Next, the comparison unit associates the light receiving elements arranged in the light on part corresponding region and the light receiving elements arranged in the light off part corresponding region on a one-to-one basis in the arrangement order with respect to the one direction. The difference between the outputs of the light receiving element pairs corresponding to the pair 1 added by the adder is obtained. Then, the logic operation unit performs an operation on the logic value represented by the difference signal obtained by the comparison unit taking a difference to create an output signal having a frequency different from the moving frequency.

  Therefore, even if the width of the light receiving element is equal to or less than ¼ of the input pitch length that is the sum of the lengths along one direction of a pair of adjacent light-on portions and light-off portions of the moving body, A sufficient amount of received light can be ensured by adding the signals of the plurality of light receiving elements by the adding unit. As a result, while ensuring the slit width of the moving body so as not to deteriorate the characteristics, the logic operation unit can create an output signal having a frequency higher than the moving frequency, and the resolution can be improved. Movement information such as movement speed and movement direction can be obtained more precisely. In addition, this can be performed while maintaining the pitch of the light-on part regardless of the pitch of the light-on part provided in the moving body, and therefore, the SN ratio is not lowered and the problem of crosstalk is not caused. . Further, when the moving frequency is relatively high, if the logic operation unit creates an output signal having a frequency lower than the moving frequency, waveform collapse can be prevented.

Further, according to this photoelectric encoder, the comparison unit has a one-to-one correspondence between the light receiving elements arranged in the light on part corresponding region and the light receiving elements arranged in the light off part corresponding region in the arrangement order in the one direction. The difference between the outputs added by the adder of the light receiving element pair corresponding to the one-to-one correspondence is taken. That is, the difference between outputs whose phases are shifted by 180 ° with respect to the moving frequency is taken. Thereby, background noise can be accurately removed. Therefore, it is possible to accurately detect the passage of the moving body between the light-on part and the light-off part. In addition, the light receiving elements having substantially the same width are arranged in the light-on portion corresponding region and the light-off portion corresponding region at a common constant pitch. Therefore, the group of differential signals obtained from the plurality of light receiving element pairs is the arrangement order of the plurality of light receiving element pairs (that is, the light on part corresponding region and the light off part corresponding to the pair of light receiving elements). The phases are different from each other depending on the arrangement order in the region and have the same pulse width. Therefore, the logical operation unit calculates the logical values represented by the difference signal, for example, by taking an exclusive OR (EXOR), thereby creating an output signal having a higher duty ratio than the moving frequency and having a constant duty ratio. be able to.

Further, according to this photoelectric encoder, the center position of the column formed by the plurality of light receiving elements and the center position of the column formed by the plurality of amplifiers coincide with each other in the one direction. Therefore, the lengths of the wirings from the plurality of light receiving elements to the plurality of amplifiers can be relatively well aligned. Therefore, variations in signal delay due to differences in the lengths of the wirings can be suppressed. As a result, the accuracy of the output signal is increased.

  In addition, the actual waveform of the output of each light receiving element may be close to a sine wave due to the influence of light wraparound rather than a rectangular wave. Therefore, it is desirable to provide an AD conversion unit that converts the output of each light receiving element into a digital logical value by AD (analog-digital) conversion. In such a case, the output of each of the light receiving elements is a rectangular wave, which surely represents a digital logical value. Furthermore, it is desirable to amplify the output of each light receiving element before performing the AD conversion.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups has a width of 1/16 or less of the input pitch length, and is continuously arranged at an interval of 1/16 pitch between the input pitch lengths. As well as
The plurality of light receiving element groups are arranged along the one direction.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/8 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other at an interval of 1/8 pitch, and the light receiving elements are spaced by 9/16 pitch from the four light receiving elements in the first row. Two rows of four light receiving elements are arranged adjacent to each other,
Four light receiving elements in the third row are arranged adjacent to each other at an interval of 1/8 pitch, and the light receiving elements are spaced apart from each other by 9/16 pitch with respect to the four light receiving elements in the third row. Four light receiving elements in four rows are arranged adjacent to each other,
The third column and the fourth column are 180 ° out of phase with the first column and the second column with respect to the modulation period of incident light due to the movement of the moving body, and
The plurality of light receiving element groups are arranged along the one direction.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups has a width of 1/8 or less of the input pitch length and is continuously arranged at an interval of 3/16 pitch.
The plurality of light receiving element groups are arranged along the one direction.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/4 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other at intervals of 1/4 pitch,
The four light receiving elements in the second row are arranged adjacent to each other at a pitch of 1/4 with a pitch of 16/16 with respect to the four light receiving elements in the first row.
The four light receiving elements in the third row are arranged adjacent to each other at a pitch of 1/4 with a pitch of 17/16 with respect to the four light receiving elements in the second row.
The four light receiving elements in the fourth row are arranged adjacent to each other at a quarter pitch with a pitch of 17/16 with respect to the four light receiving elements in the third row,
The plurality of light receiving element groups are arranged along the one direction.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
The width is 1/4 or less of the input pitch length and is continuously arranged at intervals of 5/16 pitch,
The plurality of light receiving element groups are arranged along the one direction.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/4 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other at intervals of 1/4 pitch,
On the same line where the first row is arranged along the one direction, the four light receiving elements in the second row are spaced apart from each other by a quarter pitch of 17/16 with respect to the four light receiving elements in the first row. Are arranged adjacent to each other,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the same line in which the first row and the second row are arranged along the one direction, an interval of ¼ pitch. The four light receiving elements in the third row are arranged adjacent to each other,
On the same line in which the third row is arranged along the one direction, the four light receiving elements in the fourth row are spaced by 1/16 pitch with a pitch of 17/16 with respect to the four light receiving elements in the third row. Are arranged adjacent to each other,
The eight light receiving elements in the first and second rows and the eight light receiving elements in the third and fourth rows are 1/8 pitch with respect to the modulation period of incident light due to the movement of the moving body. The phase difference is as follows.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/8 or less of the input pitch length, and
The eight light receiving elements in the first row are arranged adjacent to each other at an interval of 1/8 pitch,
The second row is spaced at 1/8 pitch on the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the same line arranged along the one direction. Are arranged adjacent to each other,
The eight light receiving elements in the first row and the eight light receiving elements in the second row have a phase difference of 1/16 pitch with respect to the modulation period of incident light caused by the movement of the moving body.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

Moreover, the photoelectric encoder of one embodiment is
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/4 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other on the same line along the one direction at intervals of 1/4 pitch,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the line arranged along the one direction, the second row is spaced at 1/4 pitch. Four light receiving elements are arranged adjacent to each other,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the line on which the first row and the second row are arranged along the one direction at intervals of 1/4 pitch. Four light receiving elements in the third row are arranged adjacent to each other,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the line on which the first, second, and third columns are arranged along the one direction, ¼ Four light receiving elements in the fourth row are arranged adjacent to each other at pitch intervals, and
The four light receiving elements in the first row and the four light receiving elements in the second row have a phase difference of 1/16 pitch with respect to the modulation period of incident light due to the movement of the moving body,
The four light receiving elements in the first row and the four light receiving elements in the third row have a phase difference of 1/8 pitch with respect to the modulation period of incident light due to the movement of the moving body,
The four light receiving elements in the first row and the four light receiving elements in the fourth row have a phase difference of 3/16 pitch with respect to the modulation period of incident light due to the movement of the moving body.

  According to the photoelectric encoder of the above embodiment, the plurality of light receiving element groups are obtained by combining one light receiving element from each light receiving element group, which has the same phase relationship with the modulation period of incident light due to movement of the moving body. There are 16 sets, and for each set of light receiving elements, the adder can add signals of a plurality of light receiving elements of the same set to output a signal of a sufficient level.

  In one embodiment, a dummy photodiode that is an inactive region with respect to input light is disposed between the light receiving elements adjacent to each other.

  According to the photoelectric encoder of the above embodiment, a dummy photodiode serving as an inactive region for input light is disposed between the light receiving elements adjacent to each other, and an inactive layer for incident light is disposed between the light receiving elements. By sandwiching, a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements can be suppressed.

In the photoelectric encoder of one embodiment,
For each set of light receiving elements, based on the output of the adder that adds the signals of the plurality of light receiving elements of the same set, A comparison unit that takes a difference signal between the outputs of the pair of light receiving elements in which the outputs correspond to one to one;
The logical operation unit performs a logical operation on the logical value represented by the difference signal obtained by the comparison unit.

  According to the photoelectric encoder of the above embodiment, the comparison unit modulates the moving body based on the output of the adding unit obtained by adding the signals of a plurality of light receiving elements of the same set for each set of light receiving elements. A difference signal between the outputs of the pair of light receiving elements in which the outputs of the light receiving elements whose phase is inverted by 180 ° with respect to the period is made to correspond one to one is obtained. That is, the difference between outputs whose phases are shifted by 180 ° with respect to the moving frequency is taken. Thereby, background noise can be accurately removed. Therefore, it is possible to accurately detect the passage of the moving body between the light-on part and the light-off part.

  In addition, the widths of the light receiving elements in the one direction are substantially the same, and for each set of the light receiving elements, one is disposed in the light-on portion corresponding region and the other is disposed in the light-off portion corresponding region. Thus, the difference signal obtained for each set of light receiving elements is the order of arrangement of the sets of light receiving elements (that is, the order of arrangement of the pair of light receiving elements in the light on part corresponding region and the light off part corresponding region). With different phases depending on each other and the same pulse width. Therefore, the logical operation unit calculates the logical values represented by the difference signals obtained by the comparison unit, for example, by taking an exclusive OR (EXOR), thereby obtaining a duty ratio that is higher than the moving frequency and constant. An output signal can be created.

  In the photoelectric encoder according to an embodiment, the frequency of the output signal created by the logic operation unit is an integer multiple of the moving frequency.

  It is assumed that an ASIC (Application Specific Integrated Circuit) is provided in the subsequent stage that receives this photoelectric encoder output. In the photoelectric encoder of this embodiment, since the frequency of the output signal generated by the logic operation unit is an integral multiple of the moving frequency, considering the operation of such an ASIC, the control can be performed smoothly, which is beneficial. is there.

  In the photoelectric encoder according to an embodiment, the duty ratio of the output signal generated by the logic operation unit is different from the duty ratio of the output of each light receiving element.

  Here, the “duty ratio” means a ratio between a high level period and a period (= high level period / period) in a periodic signal that repeats a high level period and a low level period.

  According to the photoelectric encoder of the above-described embodiment, the on-time of the IC (integrated circuit) provided in the subsequent stage of the photoelectric encoder is shortened to reduce current consumption, or when the moving frequency is relatively high, the waveform It can prevent crushing and is beneficial.

  In one embodiment, the light-on part and the light-off part of the moving body have the same dimensions in the one direction.

  According to the photoelectric encoder of the above embodiment, the light-on part and the light-off part of the moving body have the same dimensions with respect to the one direction. Therefore, the light receiving element corresponds to the light-on part with respect to the one direction. The same number of regions are easily arranged in the corresponding region (referred to as “light-on portion corresponding region”) and the region corresponding to the light-off portion (referred to as “light-off portion corresponding region”). In such a case, the background noise is removed by taking the difference between the output of the light receiving element arranged in the light on part corresponding region and the output of the light receiving element arranged in the light off part corresponding region. be able to. Therefore, it is possible to accurately detect the passage of the moving body between the light-on part and the light-off part.

  In the photoelectric encoder according to an embodiment, the logical operation unit takes an exclusive OR of logical values obtained from the output of the addition unit.

  According to the photoelectric encoder of the above embodiment, the logical operation unit takes an exclusive OR of the logical values obtained from the output of the addition unit. In the exclusive OR, the output changes to logic 1, logic 0, logic 1,... By switching the number of inputs that are logic 1 to odd, even, odd,. Therefore, an output signal having a frequency higher than the moving frequency can be easily created.

  In the photoelectric encoder according to an embodiment, the logical operation unit takes an exclusive OR of the logical values obtained from the output of the addition unit a plurality of times.

  According to the photoelectric encoder of the above-described embodiment, the logical operation unit performs exclusive OR of the logical values obtained from the output of the addition unit a plurality of times, so that an output signal having a frequency higher than the moving frequency can be easily obtained. Can be created. In addition, the frequency of the output signal can be increased and the number of signals can be reduced as compared with the case where exclusive OR is performed only once.

  In the photoelectric encoder according to an embodiment, the logical operation unit calculates an exclusive OR of logical values obtained from the output of the addition unit, and further calculates a logical product or a negative logical product.

  According to the photoelectric encoder of the above embodiment, the logical operation unit takes an exclusive OR of the logical values obtained from the output of the addition unit, and further takes a logical product or a negative logical product. High frequency output signals can be easily created. Moreover, the logical operation is simplified as compared with the case where the exclusive OR is repeated a plurality of times. Therefore, the number of elements constituting the logical operation unit can be reduced.

  The logical product or the negative logical product may be taken a plurality of times.

  Further, in the photoelectric encoder according to an embodiment, the logical operation unit generates a plurality of signals having a duty ratio of 3/4 by taking an exclusive OR of the logical values obtained from the output of the addition unit, A signal having a duty ratio of 1/2 is obtained by calculating a logical product or a negative logical product of these signals.

  According to the photoelectric encoder of the above-described embodiment, logical operation or negation logical product is used at a certain stage of logical operation, so that logical operation is simplified as compared with a case where exclusive OR is repeated a plurality of times. . Therefore, the number of elements constituting the logical operation unit can be reduced.

  In the photoelectric encoder according to an embodiment, the logic operation unit includes an integrated injection logic element, and performs the operation using the integrated injection logic element.

  According to the photoelectric encoder of the above-described embodiment, an integrated injection logic (IIL) element is included as a component of the logic operation unit, so that the logic operation unit can be easily configured with a bipolar IC. Therefore, it becomes easy to manufacture the light receiving element and the logical operation unit integrally.

  In the photoelectric encoder according to an embodiment, a plurality of the light receiving elements are arranged in a light-on portion corresponding region corresponding to the light-on portion of the moving body with respect to the one direction.

  According to the photoelectric encoder of the above embodiment, a plurality of light receiving elements arranged in the light-on portion corresponding region output signals having different phases. Therefore, the logical operation unit can easily create an output signal having a frequency higher than the moving frequency by calculating the logical values obtained from the output of the addition unit, for example, taking an exclusive OR (EXOR). Can do.

  In the photoelectric encoder according to an embodiment, a plurality of light receiving elements arranged in the light-on portion corresponding region have the same dimensions and are arranged at a constant pitch in the one direction.

  According to the photoelectric encoder of the embodiment, a plurality of light receiving elements arranged in the light-on portion corresponding region output signals having different phases and the same pulse width. As a result, the logic operation unit can create an output signal that is higher than the moving frequency and has a constant duty ratio.

  As described above, it is desirable to include an AD conversion unit that converts the output of each of the light receiving elements into a digital logical value by AD (analog-digital) conversion. In such a case, the output of each of the light receiving elements is a rectangular wave, which surely represents a digital logical value. Furthermore, it is desirable to amplify the output of each light receiving element before performing the AD conversion.

In the photoelectric encoder of one embodiment,
The comparison unit includes logarithmic amplifiers corresponding to the light receiving element pairs,
Each logarithmic amplifier logarithmically amplifies the difference between the outputs of the corresponding light receiving element pair.

  According to the photoelectric encoder of the above embodiment, each logarithmic amplifier of the comparison unit logarithmically amplifies a difference between outputs of a corresponding light receiving element pair. Therefore, even if the amount of light incident on each light receiving element is very small, the SN ratio (signal-to-noise ratio) can be secured, which is beneficial.

In the photoelectric encoder of one embodiment,
The comparison unit includes amplifiers corresponding to the light receiving element pairs,
The same supply current circuit for supplying a current to each of the amplifiers was provided.

  According to the photoelectric encoder of the above embodiment, the same supply current circuit supplies current to each amplifier of the comparison unit. Therefore, it is possible to easily make the amplification factors of the amplifiers the same. Therefore, the accuracy of the output signal is increased.

  In the photoelectric encoder according to the embodiment, the comparison unit uses, as a reference input, an output of a light receiving element arranged in the light-off portion corresponding region in each light receiving element pair.

  Here, “reference input” refers to a negative input of two inputs. For example, when the difference between two inputs A and A ′ is (A−A ′), it indicates A ′.

  According to the photoelectric encoder of the above-described embodiment, the comparison unit uses, as a reference input (ie, a minus input), the outputs of the light receiving elements arranged in the light-off part corresponding region in each of the light receiving element pairs. Therefore, the group of differential signals obtained from the plurality of light receiving element pairs has a phase that is different by a certain angle in the order of arrangement of the light receiving element pairs within the range of 180 ° phase shift with respect to the moving frequency, and the same pulse width. It will have something. Therefore, the logical operation unit calculates the logical values represented by the differential signal, for example, by taking an exclusive OR (EXOR), and thereby has a duty ratio (high level period and low level) higher than the moving frequency and constant. In a periodic signal that repeats a period, an output signal having a high level period / period) can be generated with high accuracy.

  Further, in the photoelectric encoder according to an embodiment, the logic operation unit receives signals obtained from a plurality of light receiving elements arranged in a light on part corresponding region corresponding to the light on part of the moving body. Based on the arrangement order of the light receiving elements, the calculation is performed in a plurality of groups to obtain a plurality of output signals having mutually different phases.

  According to the photoelectric encoder of the above embodiment, the logic operation unit performs an operation by dividing the logic value obtained from the addition unit into a plurality of groups based on the arrangement order of the plurality of light receiving elements, and having different phases. To obtain a plurality of output signals. As a result, it is possible to obtain a plurality of output signals that are higher than the moving frequency and have different phases.

  The logic operation unit performs an operation by dividing the difference signal obtained from the plurality of light receiving element pairs into a plurality of groups based on the arrangement order of the plurality of light receiving element pairs, and has a plurality of phases having mutually different phases. It is desirable to obtain an output signal.

  Moreover, in the photoelectric encoder according to an embodiment, the logic operation unit outputs signals obtained from a plurality of light receiving elements arranged in the light-on part corresponding region in the arrangement order of the plurality of light receiving elements in the one direction. Therefore, it is periodically divided into a plurality of groups.

  According to the photoelectric encoder of the above-described embodiment, a plurality of output signals having phases higher than the moving frequency and having different phases by a certain angle can be obtained. The obtained plurality of output signals are not easily affected by variations in the amount of light depending on the light emitting elements.

  In the photoelectric encoder according to an embodiment, the logical operation unit divides signals obtained from a plurality of light receiving elements arranged in the light-on unit corresponding region into two groups.

  According to the photoelectric encoder of the above embodiment, two output signals having phases higher than the moving frequency and differing from each other by 90 ° can be obtained. The two output signals obtained are less susceptible to variations in the amount of light depending on the light emitting element.

  The logic operation unit desirably divides the differential signals obtained from the plurality of light receiving element pairs into two groups alternately according to the arrangement order of the plurality of light receiving element pairs in the one direction.

  In one embodiment, the plurality of light receiving elements arranged in the light-on portion corresponding region are arranged at a constant pitch in the one direction, and the light-on portion corresponding region is equally spaced at the pitch. Each end of each of the light receiving elements is arranged correspondingly on a line divided into two.

  According to the photoelectric encoder of the embodiment, a plurality of light receiving elements arranged in the light-on portion corresponding region output signals having different phases and the same pulse width. As a result, the logic operation unit can create an output signal that is higher than the moving frequency and has a constant duty ratio. In addition, since each end of each light receiving element is arranged correspondingly on a line obtained by dividing the light-on-corresponding region at equal intervals with the pitch, each light receiving element in each divided region with respect to the one direction. The element dimensions can be maximized. Therefore, it is possible to increase the sensitivity by expanding the light receiving surface of each light receiving element.

  In the photoelectric encoder according to an embodiment, the number of the light receiving elements is k in the light on part corresponding region corresponding to the light on part of the moving body (k is a natural number of 2 or more) in the one direction. Is arranged.

  According to the photoelectric encoder of the above embodiment, k light receiving elements arranged in the light-on portion corresponding region output k signals having different phases. Therefore, the logical operation unit calculates an output signal having a frequency k times higher than the moving frequency by calculating the logical values obtained from the output of the addition unit, for example, taking an exclusive OR (EXOR). Can do.

In one embodiment, k is 3 or more, and the logic operation unit adds a logical value represented by the output of the light receiving element in the order in which the light receiving elements are adjacent in the one direction. taking exclusive OR Te.

In general, when there are three or more logical values, when taking the exclusive OR of the two logical values, first select two logical values and perform an operation, and add another logical value to the operation result. And repeat this. In the photoelectric encoder, there are various variation conditions such as light amount variation and assembly variation depending on the light emitting element, so that accuracy is improved by regularly performing the calculation order. Here, the photoelectric encoder of this embodiment, the logical value output from the light receiving element is represented, it takes the exclusive logical sum is sequentially added in the order in which the light receiving element are adjacent with respect to the one direction. Therefore, the obtained output signal is not easily affected by variations in the amount of light depending on the light emitting element.

In one embodiment of the photoelectric encoder, k is 3 or more, and the logic operation unit outputs a logical value represented by the output of the light receiving element in both end portions with respect to the one direction within the light-on unit corresponding region. Add in the order toward the arranged light receiving elements in the central portion alternately from arranged light receiving elements by taking exclusive OR.

  According to the photoelectric encoder of the above embodiment, the obtained output signal is not easily affected by the variation in the amount of light depending on the light emitting element.

  Further, in the photoelectric encoder according to an embodiment, the logic operation unit outputs signals obtained from a plurality of light receiving elements arranged in a light on part corresponding region corresponding to the light on part of the moving body to each other by 90 °. The signals are divided into two groups having different phases, and exclusive OR of the signals having phases different from each other by 90 ° is obtained.

  According to the photoelectric encoder of the above-described embodiment, the logic operation unit outputs signals obtained from a plurality of light receiving elements arranged in a light-on-corresponding region corresponding to the light-on part of the moving body to each other by 90 °. The signals are divided into two groups having different phases, and exclusive OR of the signals having phases different from each other by 90 ° is obtained. Therefore, if the exclusive OR is performed only once, an output signal having a frequency twice the moving frequency is obtained, which is beneficial.

  An electronic apparatus according to the present invention is characterized in that the photoelectric encoder according to any one of the above is used.

  According to the electronic apparatus, the photoelectric encoder detects the passage of the light-on part and the light-off part of the moving body with high accuracy. Therefore, an appropriate operation can be performed using the detection result.

Moreover, in the aspect which limited the photoelectric encoder of this invention to the light transmission type, it is defined as follows. That is, the light transmission type photoelectric encoder of the present invention is
The light-on portion of the moving body is a light transmitting portion, the light-off portion is a light blocking portion, and the moving body is arranged between the light emitting element and each light receiving element along one direction in which the light receiving elements are arranged. The light transmitting portion and the light blocking portion alternately pass at a predetermined moving frequency. As the light transmitting portion and the light blocking portion of the moving body sequentially pass through positions corresponding to the plurality of light receiving elements, the output values of the plurality of light receiving elements change sequentially. Then, the logical operation unit calculates logical values obtained from the outputs of the addition unit, and creates an output signal having a frequency higher than the moving frequency. Therefore, the resolution can be improved, and movement information such as the moving speed and moving direction of the moving body can be obtained more precisely. In addition, this can be performed while maintaining the pitch of the light transmission portion regardless of the pitch of the light transmission portion provided on the moving body, and therefore, the SN ratio is not lowered and the problem of crosstalk is not caused. .

  As is clear from the above, according to the photoelectric encoder of the present invention, a high frequency output can be obtained by performing a logical operation on each waveform obtained by arranging a plurality of light receiving elements at a narrow pitch. Further, as the division of the light receiving element is subdivided, a high frequency signal is obtained, and information on the moving body can be obtained more precisely. Further, since there is a concern that the amount of light received may decrease when the light receiving elements are subdivided, an effect of reducing crosstalk can be obtained by arranging dummy photodiodes between adjacent light receiving elements.

  Moreover, the electronic device of this invention can grasp | ascertain the movement information of a moving body correctly by using the said photoelectric encoder, and can improve performance significantly.

  Hereinafter, the photoelectric encoder of the present invention will be described in detail with reference to embodiments shown in the drawings.

  First, before describing the embodiment of the photoelectric encoder according to the present invention, the logical operation of the logical operation unit used in the present invention will be described with reference to FIGS.

  FIG. 10 shows a cross section of a detection portion of a light transmission type photoelectric encoder. In this photoelectric encoder, the light emitting portion 142 is accommodated on one side (upper side in FIG. 10) of the case 145 having the groove 147 at the substantially center, and the light receiving portion 144 is accommodated on the other side (lower side in FIG. 10). Has been. Thereby, the light emission part 142 and the light-receiving part 144 have opposed. The light emitting part 142 is configured by mounting a semiconductor light emitting chip 141 as a light emitting element on a header part 148 a of a lead frame 148 and sealing it with a transparent resin 152. The light receiving portion 144 is configured by mounting the semiconductor light receiving chip 10 including a plurality of light receiving elements on the header portion 149 a of the lead frame 149 and sealing it with a transparent resin 154. In front of the light emitting unit 142 on the optical axis 150 connecting the semiconductor light emitting chip 141 and the semiconductor light receiving chip 10, a collimating lens 146 for collimating the irradiation light of the light emitting unit 142 is disposed. In the groove 147, the disc-shaped moving body 40 provided with the light-on portion X is inserted. Here, the moving body 40 is provided with a plurality of slits as an example of the light-on portion.

  In operation, the moving body 40 rotates at a constant speed around a central axis (not shown) parallel to the optical axis 150. The light emitting chip 141 is energized through the lead frame 148, the light emitting chip 141 emits light, and light is emitted along the optical axis 150 through the collimating lens 146. The plurality of light receiving elements of the light receiving chip 10 photoelectrically convert light incident through the light-on portion X of the moving body 40 and output signals corresponding to the amount of incident light. Outputs of a plurality of light receiving elements of the light receiving chip 10 are processed by a comparison unit and a logic operation unit as described later.

  In the following example, it is assumed that the light receiving chip 10 is divided into a plurality of light emitting elements (they may be a plurality of light receiving areas in one chip).

  The upper part of FIG. 1 schematically shows a portion of the moving body 40 provided with the light-on portions X1, X2,... Perpendicular to the plate surface. The portion where the plate material exists between the light-on portions X1, X2,... Constitutes light-off portions Y1, Y2,. 1 schematically shows a plurality of light receiving elements (denoted by reference numerals 11a, 11b,...) Of the light receiving chip 10. In the lower part of FIG. In FIG. 1, the rotational direction D of the moving body 40 is approximately represented as a straight line (the same applies to the following drawings). The moving body 40 has light on portions X1, X2,... And light off portions Y1, Y2,. The light-on portions X1, X2,... And the light-off portions Y1, Y2,... Have the same 1/2 pitch (that is, P / 2) in the rotation direction D. Thereby, with respect to the rotation direction D, the region corresponding to the light-on portion X1 (referred to as “light-on portion corresponding region”) 20 and the region corresponding to the light-off portion Y1 (referred to as “light-off portion corresponding region”). The same number of light receiving elements can be easily arranged on each.

  In the example of FIG. 1, a plurality of light receiving elements 11 a, 11 b,... The light receiving elements 11a, 11b,... Have the same dimensions along the rotation direction D.

  In operation, when the moving body 40 is rotated at a constant speed as described above, the light-on portions X1, X2,... And the light-off portions Y1, Y2,. , 11b,..., 11b,..., 11b,. In counting the moving frequency f, the individual light-on parts X1, X2,... Are not distinguished, and any light-on part X1, X2,.

  2, the outputs A1 +, A2 +,... Of the respective light receiving elements 11a, 11b,... Send light from the light emitting chip 41 to the light on parts X1, X2 of the moving body 40. ,... Take a high level value according to transmission, or take a low level value according to the light-off portions Y1, Y2,. The outputs A1 +, A2 +,... Change at the same constant frequency as the moving frequency f and at different phases. In the present invention, an output signal having a frequency higher than the moving frequency f is calculated by calculating logical values represented by the plurality of outputs A1 +, A2 +,... (High level is logic 1 and low level is logic 0). Is going to get. For example, as shown in FIG. 11, it is assumed that eight signals A1, B1, A2, B2,..., A4, B4 having different phases at the same frequency (moving frequency f) are obtained by the light receiving element. As shown in FIG. 12, two of these signals are combined in this example as (A1, A3) (B1, B3) (A2, A4) (B2, B4), and each of these signals is exclusive OR (EXOR). ). As a result, four signals A11, B11, A12, and B12 having a frequency 2f that is twice each and having different phases by 45 degrees can be obtained. Thus, by taking an exclusive OR (EXOR), an output signal having a frequency higher than the moving frequency f can be easily created. Note that the duty ratio of each signal in FIGS. 11 and 12 is ½ (that is, high level period: low level period = 1: 1).

  FIG. 3 shows an example in which the same number of light receiving elements are arranged in each of the light on part corresponding region 20 and the light off part corresponding region 21 with respect to the rotation direction D. In this case, the outputs A1 +, A2 +,... Of the light receiving elements 11a, 11b,... Arranged in the light on portion corresponding area 20 and the light receiving elements 12a, 12b,. By taking the difference between the outputs A1-, A2-,..., Background noise can be removed. Therefore, the passage of the light-on portions X1, X2,... And the light-off portions Y1, Y2,.

  4 includes the regularity (constant pitch, the same dimension) of the arrangement of the light receiving elements described with reference to FIGS. 1 and 3, and more specifically, the four light receiving elements 11a, 11b, 11c, and 11d are arranged, and the same number of four light receiving elements 12a, 12b, 12c, and 12d are arranged in the light-off portion corresponding region 21. The light receiving elements 11a, 11b, 11c, and 11d output signals A1 +, A2 +, A3 +, and A4 +, respectively, and the light receiving elements 12a, 12b, 12c, and 12d output signals A1-, A2-, A3-, and A4-, respectively. As shown in FIG. 5, the outputs A1 +, A2 +, A3 +, and A4 + of the light receiving elements 11a, 11b, 11c, and 11d arranged in the light-on portion corresponding region 20 respectively have a constant moving frequency f and are mutually connected. It changes sequentially with different phases by a certain angle. Similarly, the outputs A1-, A2-, A3-, A4- of the light receiving elements 12a, 12b, 12c, 12d arranged in the light-off portion corresponding region 21 have a constant movement frequency f and a constant angle with each other. It changes sequentially at different phases. The phases of the outputs A1 +, A2 +, A3 +, A4 + and the outputs A1-, A2-, A3-, A4- are different from each other by 180 °. That is, the phase is inverted.

  FIG. 6 shows a comparison unit 45 that processes the outputs of these light receiving elements and a logic operation unit 46 that receives the output of the comparison unit 45 through a digital conversion circuit (not shown).

  The comparison unit 45 includes four comparators 41, 42, 43, 44. The comparator 41 takes the difference between the outputs A1 + and A1- of the light receiving element pairs 11a and 12a, the comparator 42 takes the difference between the outputs A2 + and A2- of the light receiving element pairs 11b and 12b, and the comparator 43 takes the light receiving element. The difference between the outputs A3 +, A3- of the pair 11c, 12c is taken, and the comparator 44 takes the difference between the outputs A4 +, A4- of the light receiving element pair 11d, 12d. That is, in this example, the light receiving elements 11a, 11b, 11c, and 11d arranged in the light-on portion corresponding region 20 and the light receiving elements 12a, 12b, 12c, and 12d arranged in the light-off portion corresponding region 21 are rotated in the rotation direction D. 1 to 1 in the order of arrangement. Outputs A1-, A2-, A3-, and A4- having a minus sign are reference inputs. That is, the outputs A1-, A2-, A3-, A4- are subtracted from the outputs A1 +, A2 +, A3 +, A4 +, respectively. The background noise can be removed by the comparators 41, 42, 43, and 44 taking the difference in this way. Therefore, the passage of the light-on portions X1, X2,... And the light-off portions Y1, Y2,.

  The logical operation unit 46 includes an exclusive OR circuit that takes an exclusive OR (EXOR) between the logical values represented by the outputs of the comparators 41, 42, 43, and 44. In the exclusive OR, the output changes to logic 1, logic 0, logic 1,... By switching the number of inputs that are logic 1 to odd, even, odd,. Therefore, the output signal A having a frequency higher than the moving frequency f can be easily created. In this four-input example, an output signal A having a frequency 4f that is four times higher than the moving frequency f can be created. Moreover, the output signal A has a constant duty ratio based on the regularity (constant pitch, same dimension) of the arrangement of the light receiving elements.

  7 is provided with regularity (constant pitch, same dimension) of the arrangement of the light receiving elements described with reference to FIGS. 1 and 3, and more specifically, eight light receiving elements in the light-on portion corresponding region 20. 11 a, 11 b, 11 c, 11 d, 11 e, 11 f, 11 g, 11 h are arranged, and the same number of the eight light receiving elements 12 a, 12 b, 12 c, 12 d, 12 e, 12 f, 12 g, 12 h are arranged in the light off part corresponding region 21. An example of arrangement is shown. The light receiving elements 11a, 11b, 11c, 11d, 11e, 11f, 11g, and 11h output signals A1 +, B1-, A2 +, B2-, A3 +, B3-, A4 +, B4-, respectively, and the light receiving elements 12a, 12b, 12c. , 12d, 12e, 12f, 12g and 12h output signals A1-, B1 +, A2-, B2 +, A3-, B3 +, A4-, B4 +.

  In this example, the comparison unit 45 shown in FIG. 6 uses the difference between the outputs A1 + and A1- of the light receiving element pairs 11a and 12a, the difference between the outputs A2 + and A2- of the light receiving element pairs 11c and 12c, The difference between the outputs A3 + and A3- of 11e and 12e and the difference between the outputs A4 + and A4- of the light receiving element pair 11g and 12g are taken. Then, an exclusive OR (EXOR) of the logical values represented by the outputs of the four comparators 41, 42, 43, and 44 is taken by the logical operation unit 46 shown in FIG. As a result, an output signal A having a frequency 4f that is four times higher than the moving frequency f is created.

  Further, the difference between the outputs B1 + and B1- of the light receiving element pairs 12b and 11b and the difference between the outputs B2 + and B2- of the light receiving element pairs 12d and 11d are obtained by the comparison unit having the same configuration as the comparison unit 45 shown in FIG. The difference between the outputs B3 + and B3- of the light receiving element pairs 12f and 11f and the difference between the outputs B4 + and B4- of the light receiving element pairs 12h and 11h are taken. Then, the logical operation unit having the same configuration as the logical operation unit 46 shown in FIG. 6 takes an exclusive OR (EXOR) between the logical values represented by the outputs of the comparison unit (four comparators). As a result, an output signal B having a frequency 4f that is four times higher than the moving frequency f is created.

  The middle part of FIG. 8 shows the arrangement of the light receiving elements of the conventional example shown in the middle part of FIG. 1, and the lower part of FIG. 8 shows the arrangement of the light receiving elements shown in FIG. In the conventional example, as shown in FIG. 9, the output signals A0 and B0 have the same frequency f as the moving frequency f, and have phases different from each other by 90 °. On the other hand, in the arrangement of the light receiving elements shown in the lower part of FIG. 8 (the arrangement shown in FIG. 7), when the above processing is applied to the output of the light receiving elements, The frequency 4f is four times higher than f, and the phases are different from each other by 90 °.

  Thereby, resolution | decomposability can be improved and movement information, such as the moving speed of the moving body 40 and a moving direction, can be obtained more precisely. In addition, this is possible even if the pitch of the light-on portions X1, X2,... Is maintained regardless of the pitch of the light-on portions X1, X2,. Does not cause degradation or crosstalk problems.

  In general, when there are three or more logical values, and taking the exclusive OR of them, first select two logical values and perform an operation, and add another logical value to the operation result. And then repeat this process. In the photoelectric encoder, since there are various variation conditions such as light amount variation and assembly variation depending on the light emitting chip 41, accuracy is improved by regularly performing the calculation sequence.

  Here, the logic operation unit 46 sequentially adds the logical values represented by the outputs of the light receiving elements 11a, 11b,... In the order in which the light receiving elements 11a, 11b,. Is desirable. Thereby, the obtained output signal is not easily affected by the variation in the amount of light depending on the light emitting chip 41.

  Further, the logic operation unit 46 alternately changes the logical value represented by the outputs of the light receiving elements 11a, 11b,... From the light receiving elements 11a, 11b,. May be added in the order toward the light receiving elements 11a, 11b,. Also in this case, the obtained output signal is not easily affected by variations in the amount of light depending on the light emitting chip 41.

  Next, a case where the logical operation is performed a plurality of times will be described.

  For example, first, as shown in the left half of FIG. 13, two signals A1, B1, A2, B2,..., A4, B4, which are sequentially different in phase at the same frequency (moving frequency f) obtained by the light receiving element, are represented by 2 In this example, in this example, (A1, A3) (B1, B3) (A2, A4) (B2, B4) are combined to obtain an exclusive OR (EXOR). As a result, as described with reference to FIG. 12, four signals A11, B11, A12, and B12 each having a double frequency and different phases by 45 degrees are obtained. Subsequently, as shown in the right half of FIG. 13, two of these signals, in this example, (A11, A12) (B11, B12) are combined to obtain an exclusive OR (EXOR). As a result, two signals A21 and B21 having a frequency 4f that is four times the original moving frequency f and differing in phase by 90 ° are obtained. Thus, by taking the exclusive OR twice, the frequency of the output signal can be increased and the number of signals can be reduced.

  Further, as shown in FIG. 14, an exclusive OR (EXOR) between these signals A21 and B21 is taken to create a signal A31 having a frequency 8f that is eight times the original moving frequency f. You can also. Note that the duty ratio of each signal in FIGS. 13 and 14 is ½ (that is, high level period: low level period = 1: 1).

  In this way, a signal having a frequency twice as high as the original moving frequency can be obtained by performing exclusive OR (EXOR) of signals having phases different from each other by 90 ° a plurality of times. Then, a signal having a frequency that is an integral multiple of the original moving frequency, more specifically 2m times (where m is a natural number) can be obtained by repeating such an operation a plurality of times.

  Further, for example, as shown in FIG. 15, after obtaining four signals A11, B11, A12, and B12 each having a double frequency and different phases by 45 degrees, unlike the previous example, (A11, B11 ) (A12, B12) may be combined to obtain an exclusive OR (EXOR). As a result, two signals A22 and B22 having a frequency 2f that is twice the original moving frequency f and differing in phase by 90 ° are obtained. The duty ratios of these signals A22 and B22 are both 3/4 (that is, high level period: low level period = 3: 1). Further, if a logical product (AND) or a negative logical product (NAND) of these signals A22 and B22 is taken, a signal A31 having a frequency 8f that is eight times the original moving frequency f can be created. .

  Further, as shown in FIG. 16, for example, two signals A1, B1, A2, B2,..., A4, B4, which are sequentially different in phase at the same frequency (moving frequency f) obtained by the light receiving element, In this example, the exclusive OR (EXOR) may be obtained by combining (A1, A2) (A3, A4) (B1, B2) (B3, B4). As a result, four signals A13, A14, B13, and B14 having the same frequency as the moving frequency f and different phases are obtained. That is, the phase differs by 90 ° between the signals (A13, A14) and (B13, B14), and the phase differs by 67.5 ° between the signals (A13, B13). The duty ratios of these signals A13, A14, B13, and B14 are all 3/4 (that is, the high level period: the low level period = 3: 1). Next, these signals are combined two by two in this example as (A13, A14) (B13, B14) to obtain a logical product (AND) or a negative logical product (NAND). As a result, two signals A21 and B21 having a frequency 4f that is four times the original moving frequency f and having phases different from each other by 90 ° are obtained.

  Further, as shown in the right half of FIG. 17, an exclusive OR (EXOR) of these signals A21 and B21 is taken, and a signal A31 having a frequency 8f that is 8 times the original moving frequency f is obtained. It can also be created.

  In this way, by using logical product (AND) or negative logical product (NAND) at a certain stage of the logical operation, the logical operation is simplified as compared with the case where exclusive OR is repeated a plurality of times. . Therefore, the number of elements constituting the logical operation unit can be reduced. Thereby, in an IC (integrated circuit) provided in the subsequent stage of this photoelectric encoder, signal processing is facilitated, which is beneficial.

  In this photoelectric encoder, it is desirable to use, for example, an integrated injection logic element (hereinafter referred to as “IIL element”) having an equivalent circuit as shown in FIG. In such a case, the logical operation unit can be easily configured with a bipolar IC. Therefore, it becomes easy to manufacture the light receiving element and the logical operation unit integrally. In addition, since one IIL element constitutes a NAND (Negative AND) circuit, the use of the IIL element simplifies the configuration of the logical operation unit.

  For example, the logical operation shown in FIG. 16 is realized by a circuit (logical operation unit) as shown in FIG. 19 when an IIL element is used as a component of the logical operation unit. The logical operation unit shown in FIG. 19 is exclusive of an amplification unit (AMP) 50 that amplifies signals A1, B1, A2, B2,..., A4, B4 signals obtained by the light receiving elements, and performs exclusive OR. A logical sum part (EXOR) 60 and negative logical product circuits (NANDs) 70 and 71 for taking a negative logical product are provided. The amplification unit (AMP) 50 includes amplification circuits 51, 52,..., 58 for each signal, and the exclusive OR unit (EXOR) 60 includes two signals (A1, A2) (A3, A4) (B1, B2). An exclusive OR circuit 61, 62, 63, 64 is provided for each (B3, B4). Each of the exclusive OR circuits 61, 62, 63 and 64 includes two NAND circuits (NANDs). Since each NAND circuit in FIG. 19 is configured by one IIL element, the configuration of the logical operation unit is simplified.

  FIG. 21 exemplifies a schematic block configuration of the photoelectric encoder in the case where the logical operation shown in FIG. 12 is performed.

  This photoelectric encoder includes a light receiving unit 81, a current amplifying unit 82, a diode unit 83, a differential amplifying unit 84 as a comparison unit, and an AD converting unit 85, which are integrally formed on the same semiconductor substrate 80. , A logic circuit unit 86, an output circuit unit 87, a constant current circuit 88, and a constant voltage circuit 89. The light receiving unit 81 includes eight pairs of light receiving elements PDA1 + to PDB4- (in real space, arranged in the same order as the light receiving elements in FIG. 7 along the rotation direction D). The current amplifier 82 includes a current amplifier corresponding to each light receiving element, and each current amplifier amplifies the output of the corresponding light receiving element in an analog state. The diode unit 83 includes diodes corresponding to the respective current amplifiers, and each of the diodes converts the output of the corresponding current amplifier into a voltage. The differential amplifying unit 84 includes differential amplifiers 51, 52,..., 58 corresponding to the respective diode pairs (and hence the respective light receiving element pairs), and the differential amplifiers 51, 52,. The difference between the outputs of the diode pair is logarithmically compressed and amplified. That is, a logarithmic amplifier is composed of the diode pair and the differential amplifier. Therefore, even if the amount of light incident on each light receiving element is very small, an SN ratio (signal to noise ratio) can be ensured. The AD converter 85 includes AD converters ADC1, ADC2,..., ADC8 corresponding to the differential amplifiers 51, 52,..., 58, and each AD converter ADC1, ADC2,. The outputs of 51, 52,..., 58 are AD converted to output digital logic values. The logic circuit section 86 includes each pair (51, 53) (52, 54) (55, 57) (56, 58) of the differential amplifiers, and thus each pair (ADC1, ADC3) (ADC2, ADC4) (ADC5, ADC7) (ADC6, ADC8) corresponding to exclusive OR circuits EXOR1, EXOR2, EXOR3, EXOR4. Each exclusive OR circuit EXOR1, EXOR2, EXOR3, and EXOR4 has a corresponding pair of differential amplifiers (51, 53) (52, 54) (55, 57) (56, 58), and therefore an AD converter. An exclusive OR of outputs is taken between each pair (ADC1, ADC3) (ADC2, ADC4) (ADC5, ADC7) (ADC6, ADC8). The output circuit unit 87 includes amplifier circuits OC1, OC2, OC3, and OC4 including two transistors corresponding to the exclusive OR circuits EXOR1, EXOR2, EXOR3, and EXOR4. The amplifier circuits OC1, OC2, OC3, and OC4 correspond to each other. The output of the exclusive OR circuit (EXOR) is amplified and output to the output terminals VOA1, VOA2, VOB1, and VOB2, respectively. VCC represents a terminal to which a power supply voltage is supplied, and GND represents a terminal to be grounded. A constant current circuit 88 and a constant voltage circuit 89 supply a constant current and a constant voltage to each part of the photoelectric encoder.

  FIG. 20 illustrates a schematic configuration of a conventional photoelectric encoder. This photoelectric encoder includes a light receiving unit 181, a current amplification unit 182, a diode unit 183, a differential amplification unit 184 as a comparison unit, and an AD conversion unit 185 that are integrally formed on the same semiconductor substrate 180. The output circuit unit 187 and the constant voltage circuit 189 are provided. Each component corresponding to the component in FIG. 21 is given a reference numeral that is larger by 100 (each description is omitted). As can be seen from a comparison between FIG. 20 and FIG. 21, the photoelectric encoder shown in FIG. 21 handles a large number of signals. Therefore, consistency is required for the circuit. For example, it is assumed that the differential amplifiers 51, 52,..., 58 shown in FIG. Each of the differential amplifiers 51, 52,..., 58 is supplied with a current from a current supply source 90 (included in the constant current circuit 88 in FIG. 21).

  In such a case, the current supply sources 90 of the differential amplifiers 51, 52,..., 58 are configured by the same supply current circuit as shown in FIG. It is desirable to supply current to 52,..., 58 (indicated as AMP1, AMP2, AMP3,. This makes it possible to provide current matching between the differential amplifiers 51, 52,..., 58, and to easily make the amplification factors of the differential amplifiers 51, 52,. As a result, the accuracy of the output signal can be increased.

  In addition, since the output current of the light receiving elements PDA1 + to PDB4- is as small as several hundred nA, the layout from the light receiving elements PDA1 + to PDB4- to the differential amplifiers 51, 52,. is there.

  For example, as shown in FIG. 24, in real space, columns 99a and 99b formed by differential amplifiers 51, 52,..., 58 are arranged along a column 98 formed by light receiving elements PDA1 + to PDB4-, and light receiving elements PDA1 + to PDA1 + to It is desirable that the center position 98c of the row 98 formed by the PDB4- and the center position 99c of the rows 99a, 99b formed by the differential amplifiers 51, 52,. That is, with respect to a straight line connecting the center positions 98c and 99c (a straight line perpendicular to the D direction on the semiconductor substrate 80), the column 98 formed by the light receiving elements PDA1 + to PDB4- and the differential amplifiers 51, 52,. It is desirable that the rows 99a and 99b formed by 58 are arranged symmetrically.

  According to such a layout, the length of each wiring 97 from the plurality of light receiving elements PDA1 + to PDB4- to the plurality of differential amplifiers 51, 52,. Therefore, variation in signal delay due to the difference in length of each wiring 97 can be suppressed. As a result, the accuracy of the output signal can be increased. Further, in the layout of FIG. 24, each pair (51, 53) (52, 54) (55, 57) (56, 58) of differential amplifiers for which an exclusive OR is taken is arranged adjacent to each other in the D direction. Therefore, the difference in length from each pair (51, 53) (52, 54) (55, 57) (56, 58) of the differential amplifier to the exclusive OR circuit EXOR1, EXOR2, EXOR3, EXOR4 Variations in signal delay due to the noise can be suppressed. Therefore, the accuracy of the output signal can be further increased.

  FIG. 25 shows in more detail the arrangement of the light receiving elements PDA1 + to PDB4- described above (the same arrangement as in FIG. 7). As shown in FIG. 25, with respect to the D direction, each end of the light receiving elements PDA1 + to PDB4- has lines V, V,... Obtained by dividing the light-on portion corresponding region 20 and the light-off portion corresponding region 21 into eight equal intervals. It is arranged corresponding to the top. Therefore, the dimensions of the light receiving elements PDA1 + to PDB4- can be maximized in the divided areas with respect to the D direction. Therefore, the light receiving surfaces of the light receiving elements PDA1 + to PDB4- can be widened to increase the sensitivity.

  In the electronic apparatus including the above-described photoelectric encoder, the photoelectric encoder detects the passage of the light-on portions X1, X2,... And the light-off portions Y1, Y2,. Therefore, an appropriate operation can be performed using the detection result.

  Next, an embodiment of the photoelectric encoder using the logical operation described in FIGS. 1 to 25 will be described with reference to FIGS. 27C to 42.

(First embodiment)
27A shows the light-on portions X1, X2,... (Light transmission portion) and the light-off portions Y1, Y2,... (Light shielding portions) of the movable body 40 in the transmission type of the photoelectric encoder according to the first embodiment of the present invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically.

  The photoelectric encoder according to the first embodiment includes a light emitting element (not shown) and a plurality of light receiving elements PD01 to PD16,... Arranged in one direction in a region where light from the light emitting element can reach. It has. A predetermined position corresponding to each of the light receiving elements PD01 to PD16,... Along the one direction is a light on portion X1, X2,... (Light transmitting portion) and a light off portion Y1, Y2,. The moving body 40 having alternating turns passes at a predetermined moving frequency. The light on portions X1, X2,... (Light transmitting portion) and the light off portions Y1, Y2,... (Light shielding portion) are in a state where light from the light emitting elements is incident on the light receiving elements PD01 to PD16,. Create a state that does not. The outputs of the light receiving elements PD01 to PD16,... Take values according to whether light from the light emitting elements is incident or not incident on the light receiving elements. Further, the width of each of the light receiving elements PD01 to PD16,... (The length in the moving direction of the light-on portions X1, X2,... And the light-off portions Y1, Y2,. The width of each of the light receiving elements PD01 to PD16,... Is substantially equal to or less than 1/16 of the input pitch length P that is the sum of the lengths of the pair of light-on portions and light-off portions along the one direction.

  The plurality of light receiving elements PD01 to PD16,... Are divided into a plurality of light receiving element groups each including 16 light receiving elements PD01 to PD16. The 16 light receiving elements PD01 to PD16 of the plurality of light receiving element groups are continuously arranged on the same line (arc) along one direction at intervals of 1/16 pitch during the input pitch length P. ing. The plurality of light receiving element groups are also arranged on the same line (arc) along the one direction.

  27B is a diagram for explaining the configuration of the adders ADD01 to ADD16, the comparators CP1 to CP8, and the logic operation unit 200 that calculate the outputs of the light receiving elements PD01 to PD16,... Of the photoelectric encoder.

  The plurality of light receiving element groups have 16 sets in which light receiving elements having the same phase relationship with respect to the modulation period of incident light due to movement of the moving body 40 are combined one by one from each light receiving element group. Then, the adders ADD01 to ADD16 add and output signals of a plurality of light receiving elements of the same set for each set of light receiving elements. That is, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added, the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added, and similarly, the outputs of the light receiving elements PD03 to PD16 of the plurality of light receiving element groups are added. I do. Next, based on the outputs of the adders ADD01 to ADD16, the outputs of the light receiving elements whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40 are made to correspond one-to-one by the comparators CP1 to CP8. The differential signal between the outputs of the pair of light receiving elements is taken. Then, the logical operation unit 200 calculates logical values obtained from the outputs of the comparison units CP1 to CP8 to create an output signal having a frequency different from the moving frequency.

  The light receiving elements PD01 to PD16 are continuously arranged at an interval of 1/16 pitch, and the outputs of the light receiving elements PD01 to PD16 are a group of independent output phases having different phase relationships.

  Here, Table 1 shows the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder.

  In the lower part of FIG. 27C, the outputs of the light receiving elements PD01 to PD16 arranged in the light on part corresponding region and the light off part corresponding region of the moving body 40 are sequentially moved at a constant moving frequency and with a certain phase difference. It shows a changing state.

  As shown in FIG. 27C, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference by modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the drawing.

  In FIG. 27C, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the moving period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the adders ADD01 to ADD16 add the outputs of the light receiving elements PD01 of the plurality of light receiving element groups, add the outputs of the light receiving elements PD02 of the plurality of light receiving element groups, and similarly. Addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the outputs of the light receiving elements whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40 are made to correspond one-to-one by the comparators CP1 to CP8. The differential signal between the outputs of the pair of light receiving elements is taken. Then, a differential signal is obtained from the outputs of the comparison units CP1 to CP8 by the subsequent logical operation unit 200, and the logical operation is performed by the logical operation unit 200 using the phase difference of the difference signal, thereby moving the mobile unit 40. It is possible to generate a signal that is synchronized with the moving frequency and higher than the moving frequency.

  Here, the comparison units CP1 to CP8 and the logic operation unit 200 use the comparison unit and the logic operation unit described with reference to FIGS.

  The width of the light receiving elements PD01 to PD16,... Is less than or equal to ¼ of the input pitch length P, which is the sum of the lengths along one direction of the pair of light-on and light-off parts adjacent to the moving body 40. In addition, it is possible to secure a sufficient amount of received light by adding the signals of the plurality of light receiving elements of the same set by the adders ADD01 to ADD16. This makes it possible for the logic operation unit 200 to create an output signal having a frequency higher than the moving frequency while ensuring the slit width of the moving body 40 so that the characteristics are not deteriorated, and the resolution can be improved. Movement information such as the movement speed and movement direction of the body can be obtained more precisely. In addition, this is possible even if the pitch of the light-on portion is maintained regardless of the pitch of the light-on portion provided in the moving body 40, and this may cause a decrease in the SN ratio and a problem of crosstalk. Absent. Further, when the moving frequency is relatively high, if the logic operation unit 200 creates an output signal having a frequency lower than the moving frequency, it is possible to prevent waveform collapse.

  FIG. 28 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 27C, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Second Embodiment)
FIG. 29A shows light on portions X1, X2,... (Light transmitting portion) and light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder of the second embodiment of the present invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the second embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder according to the second embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is 1/8 or less of the input pitch length P which is the sum of the lengths of the pair of adjacent light-on portions and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. Sixteen light receiving elements PD01 to PD16 constitute one light receiving element group, and a plurality of light receiving element groups are arranged on the same line along the one direction.

  In the light receiving element group, four light receiving elements PD01 to PD04 in the first row are arranged adjacent to each other at an interval of 1/8 pitch, and 9 / with respect to the four light receiving elements PD01 to PD04 in the first row. Four light receiving elements PD05 to PD08 in the second row are arranged adjacent to each other at a pitch of 1/8 with a spacing of 16 pitches. Here, “9/16 pitch apart” means that the interval between the center of the first row and the center of the second row is 9/16 of the input pitch length P. Further, the four light receiving elements PD09 to PD12 in the third row are arranged adjacent to each other at an interval of 1/8 pitch, and the 9/16 pitch is separated from the four light receiving elements PD09 to PD12 in the third row. Four light receiving elements PD13 to PD16 in the fourth row are arranged adjacent to each other at an interval of 1/8 pitch. The third row and fourth row PD09 to PD16 are 180 ° out of phase with the first row and second row PD01 to PD08 with respect to the modulation period of incident light caused by movement of the moving body 40. In FIG. 29A, the eight light receiving elements PD09 to PD16 in the third row and the fourth row are arranged at a 3/2 pitch with respect to the eight light receiving elements PD01 to PD08 in the first row and the second row. . Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, Table 2 shows the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder.

  On the lower side of FIG. 29B, the outputs of a plurality of light receiving elements PD01 to PD16 arranged in the light-on portion corresponding region and the light-off portion corresponding region of the moving body 40 each have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 29B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference by modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the figure.

  In FIG. 29B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the movement period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, it is possible to generate a signal that is synchronized with the moving frequency of the moving body 40 and that has a higher frequency than the moving frequency.

  The photoelectric encoder of the second embodiment has the same effect as the photoelectric encoder of the first embodiment.

  FIG. 30 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 29B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Third embodiment)
FIG. 31A shows light on portions X1, X2,... (Light transmitting portion) and light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder of the third embodiment of the present invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the third embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder of the third embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is 1/8 or less of the input pitch length P which is the sum of the lengths of the pair of adjacent light-on portions and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. The 16 light receiving elements PD01 to PD16 constitute one light receiving element group, and the light receiving elements PD01 to PD16 are continuously arranged at intervals of 3/16 pitch. A plurality of light receiving element groups are arranged on the same line along the one direction.

  Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder is shown in Table 3.

  On the lower side of FIG. 31B, the outputs of the light receiving elements PD01 to PD16 arranged in the light-on portion corresponding region and the light-off portion corresponding region of the moving body 40 each have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 31B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference by modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the drawing.

  In FIG. 31B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the moving period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, it is possible to generate a signal that is synchronized with the moving frequency of the moving body 40 and that has a higher frequency than the moving frequency.

  The photoelectric encoder of the third embodiment has the same effect as the photoelectric encoder of the first embodiment.

  FIG. 32 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 31B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Fourth embodiment)
FIG. 33A shows the light on portions X1, X2,... (Light transmitting portion) and the light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder of the fourth embodiment of the invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the fourth embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder of the fourth embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is equal to or less than ¼ of the input pitch length P, which is the sum of the lengths of the pair of adjacent light-on and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. Sixteen light receiving elements PD01 to PD16 constitute one light receiving element group, and a plurality of light receiving element groups are arranged on the same line along the one direction.

  In the light receiving element group, four light receiving elements PD01 to PD04 in the first row are arranged adjacent to each other at intervals of 1/4 pitch. Further, the four light receiving elements PD05 to PD08 in the second row are arranged adjacent to each other at a quarter pitch with a pitch of 17/16 with respect to the four light receiving elements PD01 to PD04 in the first row. Yes. Here, “17/16 pitch apart” means that the distance between the center of the first row and the center of the second row is a 17/16 interval of the input pitch length P. Further, the four light receiving elements PD09 to PD12 in the third row are arranged adjacent to each other at a quarter pitch with a 17/16 pitch from the four light receiving elements PD05 to PD08 in the second row. Yes. Further, the four light receiving elements PD013 to PD16 in the fourth row are arranged adjacent to each other by a quarter pitch with a 17/16 pitch from the four light receiving elements PD09 to PD12 in the third row. Yes. Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, Table 4 shows the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder.

  In the lower part of FIG. 33B, the outputs of a plurality of light receiving elements PD01 to PD16 arranged in the light-on portion corresponding region and the light-off portion corresponding region of the moving body 40 each have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 33B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference by modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the drawing.

  In FIG. 33B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the moving period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, it is possible to generate a signal that is synchronized with the moving frequency of the moving body 40 and that has a higher frequency than the moving frequency.

  The photoelectric encoder of the fourth embodiment has the same effect as the photoelectric encoder of the first embodiment.

  FIG. 34 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 33B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Fifth embodiment)
FIG. 35A shows the light on portions X1, X2,... (Light transmitting portion) and the light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder of the fifth embodiment of the invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the fifth embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder of the fifth embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is equal to or less than ¼ of the input pitch length P, which is the sum of the lengths of the pair of adjacent light-on and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. The 16 light receiving elements PD01 to PD16 constitute one light receiving element group, and the light receiving elements PD01 to PD16 are continuously arranged at intervals of 5/16 pitch. A plurality of light receiving element groups are arranged on the same line along the one direction.

  Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder is shown in Table 5.

  The lower side of FIG. 35B shows that the outputs of the light receiving elements PD01 to PD16 arranged in the light on part corresponding region and the light off part corresponding region of the moving body 40 have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 35B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference by modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the figure.

  In FIG. 35B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the movement period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, a signal that is synchronized with the moving frequency of the moving body 40 and that is higher in frequency than the moving frequency can be generated.

  The photoelectric encoder of the fifth embodiment has the same effect as the photoelectric encoder of the first embodiment.

  FIG. 36 shows a state in which a dummy photodiode PDX for suppressing crosstalk is arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 35B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Sixth embodiment)
FIG. 37A shows light on portions X1, X2,... (Light transmitting portion) and light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder according to the sixth embodiment of the present invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the sixth embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder of the sixth embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is equal to or less than ¼ of the input pitch length P, which is the sum of the lengths of the pair of adjacent light-on and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. Sixteen light receiving elements PD01 to PD16 constitute one light receiving element group, and a plurality of light receiving element groups are arranged along the one direction.

  In the light receiving element group, four light receiving elements PD01 to PD04 in the first row are arranged adjacent to each other at intervals of 1/4 pitch. In addition, the first row is arranged on the same line arranged along the one direction with respect to the four light receiving elements PD01 to PD04 in the first row with a pitch of 17/16 and a second pitch of 1/4. Four light receiving elements PD05 to PD08 in a row are arranged adjacent to each other. Here, “17/16 pitch apart” means that the distance between the center of the first row and the center of the second row is 17/16 of the input pitch length P. Further, the first row and the second row are ¼ pitch on the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body 40 from the same line where the first row and the second row are arranged along the one direction. The four light receiving elements PD09 to PD12 in the third row are arranged adjacent to each other at an interval of. In addition, the third row is arranged on the same line arranged along the one direction with respect to the four light receiving elements PD09 to PD12 in the third row at a pitch of 1/16 with a spacing of 17/16. Four light receiving elements PD13 to PD16 in a row are arranged adjacent to each other. The eight light receiving elements PD01 to PD08 in the first column and the second column and the eight light receiving elements PD09 to PD16 in the third column and the fourth column correspond to the modulation period of incident light due to the movement of the moving body 40. The phase difference is 1/8 pitch.

  Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, Table 6 shows the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder.

  In the lower part of FIG. 37B, the outputs of a plurality of light receiving elements PD01 to PD16 arranged in the light on part corresponding region and the light off part corresponding region of the moving body 40 each have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 37B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference due to modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the drawing.

  In FIG. 37B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the movement period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, it is possible to generate a signal that is synchronized with the moving frequency of the moving body 40 and that has a higher frequency than the moving frequency.

  The photoelectric encoder of the sixth embodiment has the same effect as the photoelectric encoder of the first embodiment.

  FIG. 38 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 37B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Seventh embodiment)
FIG. 39A shows light on portions X1, X2,... (Light transmitting portion) and light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder according to the seventh embodiment of the present invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the seventh embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder of the seventh embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is 1/8 or less of the input pitch length P which is the sum of the lengths of the pair of adjacent light-on portions and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. Sixteen light receiving elements PD01 to PD16 constitute one light receiving element group, and a plurality of light receiving element groups are arranged along the one direction.

  In the light receiving element group, eight light receiving elements PD01 to PD08 in the first row are arranged adjacent to each other at an interval of 1/8 pitch. Further, the first row is arranged on the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body 40 from the same line arranged along the one direction at intervals of 1/8 pitch. Two rows of eight light receiving elements PD09 to PD16 are arranged adjacent to each other. The eight light receiving elements PD01 to PD08 in the first row and the eight light receiving elements PD09 to PD16 in the second row have a phase difference of 1/16 pitch with respect to the modulation period of incident light due to the movement of the moving body. Have.

  Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, Table 7 shows the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder.

  In the lower side of FIG. 39B, the outputs of the light receiving elements PD01 to PD16 arranged in the light on part corresponding region and the light off part corresponding region of the moving body 40 have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 39B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference by modulation of transmitted light due to movement of the moving body 40 indicated by an arrow in the figure.

  In FIG. 39B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the moving period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, it is possible to generate a signal that is synchronized with the moving frequency of the moving body 40 and that has a higher frequency than the moving frequency.

  The photoelectric encoder of the seventh embodiment has the same effect as the photoelectric encoder of the first embodiment.

  FIG. 40 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 39B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

(Eighth embodiment)
FIG. 41A shows light on portions X1, X2,... (Light transmitting portion) and light off portions Y1, Y2,... (Light shielding portion) of the movable body 40 in the transmission type of the photoelectric encoder according to the eighth embodiment of the present invention. The arrangement | positioning relationship of an area | region and a light receiving element is shown typically. The photoelectric encoder of the eighth embodiment has the same configuration as the photoelectric encoder of the first embodiment except for the width and arrangement of the light receiving elements.

  In the photoelectric encoder of the eighth embodiment, the width of the plurality of light receiving elements PD01 to PD16,... (The length in the moving direction of the light on portions X1, X2,... And the light off portions Y1, Y2,. ) Is 1/8 or less of the input pitch length P which is the sum of the lengths of the pair of adjacent light-on portions and light-off portions of the moving body 40 along the one direction, and each of the light receiving elements PD01 to PD16,. The widths of are substantially the same. Sixteen light receiving elements PD01 to PD16 constitute one light receiving element group, and a plurality of light receiving element groups are arranged along the one direction.

  In the light receiving element group, four light receiving elements PD01 to PD04 in the first row are arranged adjacently on the same line along the one direction at intervals of 1/4 pitch. Further, second lines are spaced at 1/4 pitch intervals on a line along the one direction shifted in a direction perpendicular to the moving direction of the moving body 40 from the line on which the first row is arranged along the one direction. Four light receiving elements PD05 to PD08 in a row are arranged adjacent to each other. Further, on the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body 40 from the line on which the first row and the second row are arranged along the one direction, the pitch is 1/4. Four light receiving elements PD09 to PD12 in the third row are arranged adjacent to each other at intervals. Further, on the line along the one direction shifted from the line in which the first column, the second column, and the third column are arranged along the one direction in a direction perpendicular to the moving direction of the moving body 40, 1 Four light receiving elements PD13 to PD16 in the fourth row are arranged adjacent to each other at intervals of / 4 pitch. The four light receiving elements PD01 to PD04 in the first row, the four light receiving elements PD05 to PD08 in the second row, the four light receiving devices PD09 to PD12 in the third row, and the four light receiving devices PD13 in the fourth row. ~ PD16 has a phase difference of 1/16 pitch with respect to the modulation period of incident light due to movement of the moving body 40.

  Each output of the light receiving elements PD01 to PD16 is a group of independent output phases having different phase relationships.

  Here, Table 8 shows the correspondence of the outputs of the light receiving elements PD01 to PD16 of the photoelectric encoder.

  On the lower side of FIG. 41B, the outputs of the light receiving elements PD01 to PD16 arranged in the light on part corresponding region and the light off part corresponding region of the moving body 40 have a constant moving frequency and a constant phase difference from each other. The state which changes sequentially is shown.

  As shown in FIG. 41B, each output of each of the light receiving elements PD01 to PD16 forms an output waveform having a phase difference due to the modulation of transmitted light due to the movement of the moving body 40 indicated by the arrow in the drawing.

  In FIG. 41B, outputs A1 + and A1-, outputs A2 + and A2-, outputs A3 + and A3-, outputs A4 + and A4-, outputs B1 + and B1-, and outputs B2 + are 180 degrees out of phase with respect to the moving period. B2-, outputs B3 + and B3-, and outputs B4 + and B4- are shown corresponding to each other (a combination in which differential signals are formed by comparison units CP1 to CP8 in the subsequent stage). Output A1 + and A1-, Output A2 + and A2-, Output A3 + and A3-, Output A4 + and A4-, Output B1 + and B1-, Output B2 + and B2-, Output B3 + and B3-, Output B4 + and B4- The phase between the sets has a phase difference corresponding to 1/16 of the input pitch length P.

  In the photoelectric encoder, first, the outputs of the light receiving elements PD01 of the plurality of light receiving element groups are added by the adders ADD01 to ADD16 (shown in FIG. 27B), and the outputs of the light receiving elements PD02 of the plurality of light receiving element groups are added. In the same manner, addition is performed for the light receiving elements PD03 to PD16 of the plurality of light receiving element groups. Next, based on the outputs of the adders ADD01 to ADD16, the comparators CP1 to CP8 (shown in FIG. 27B) output 1 of the light receiving element whose phase is inverted by 180 ° with respect to the modulation period due to the movement of the moving body 40. A difference signal between the outputs of the pair of light receiving elements corresponding to the pair 1 is taken. Then, the subsequent logic operation unit 200 (shown in FIG. 27B) obtains a difference signal from the outputs of the comparison units CP1 to CP8, and performs a logic operation by the logic operation unit 200 using the phase difference of the difference signal. Thus, it is possible to generate a signal that is synchronized with the moving frequency of the moving body 40 and that has a higher frequency than the moving frequency.

  The photoelectric encoder of the eighth embodiment has the same effects as the photoelectric encoder of the first embodiment.

  FIG. 42 shows a state in which dummy photodiodes PDX for suppressing crosstalk are arranged between adjacent light receiving elements in the arrangement of the light receiving elements in FIG. 41B, and an inactive layer is sandwiched between the light receiving elements with respect to incident light. This suppresses a decrease in the S / N ratio due to leakage of photocurrent between the light receiving elements.

  In the first to eighth embodiments, the light transmission type photoelectric encoder has been described. However, the present invention is not limited thereto. The present invention is similarly applied to a light reflection type photoelectric encoder. However, as described above, in the light reflection type, contrary to the light transmission type, the slit of the moving body corresponds to a light off portion where light is not incident on the light receiving element, and a portion made of a plate material between the slits ( A portion that reflects light corresponds to a light-on portion where light is incident on the light receiving element.

  The photoelectric encoder of the present invention is particularly suitable for use in printing machines such as copying machines and printers, FA equipment, and the like.

FIG. 1 is a diagram schematically showing the arrangement of moving bodies and light receiving elements in the photoelectric encoder of the present invention. FIG. 2 is a diagram showing an output signal obtained by calculating the output of the light receiving element in FIG. 1 and the logical values represented by the output. FIG. 3 is a diagram schematically showing a state in which light receiving elements are arranged in the light-on portion corresponding region and the light-off portion corresponding region. FIG. 4 is a diagram schematically showing a state in which four light receiving elements are arranged in each of the light-on portion corresponding region and the light-off portion corresponding region. FIG. 5 is a diagram showing the output of the light receiving element in FIG. FIG. 6 is a diagram illustrating a configuration of a comparison unit and a logic circuit unit included in the photoelectric encoder. FIG. 7 shows a state in which eight light receiving elements are arranged in each of the light on part corresponding region and the light off part corresponding region, and these light receiving elements are alternately divided into two groups in the arrangement order along the rotation direction of the moving body. FIG. FIG. 8 is a diagram schematically showing the arrangement of the light receiving elements in the conventional example and the arrangement of the light receiving elements in the embodiment with respect to the moving body. FIG. 9 is a diagram showing a comparison between the output of the light receiving element in the conventional example shown in FIG. 8 and the output of the light receiving element in one embodiment. FIG. 10 is a diagram illustrating a configuration of a detection unit of the photoelectric encoder. FIG. 11 is a diagram schematically showing the waveform of a signal obtained from the output of each of the eight light receiving elements in FIG. FIG. 12 is a diagram schematically illustrating a logical operation performed using each signal in FIG. FIG. 13 is a diagram schematically illustrating a logical operation performed using each signal in FIG. FIG. 14 is a diagram schematically illustrating a logical operation performed using each signal in FIG. FIG. 15 is a diagram schematically illustrating a logical operation performed using each signal in FIG. FIG. 16 is a diagram schematically illustrating a logical operation performed using each signal in FIG. FIG. 17 is a diagram schematically illustrating a logical operation performed using each signal in FIG. FIG. 18 is a diagram schematically showing an equivalent circuit of one IIL element. FIG. 19 is a block diagram showing a circuit configuration of a logical operation unit configured using IIL elements so as to execute the logical operation shown in FIG. FIG. 20 is a diagram showing a block configuration of a conventional photoelectric encoder. FIG. 21 is a block diagram of a photoelectric encoder according to an embodiment of the present invention adapted to perform the logical operation shown in FIG. FIG. 22 is a block diagram showing a circuit configuration of the differential amplifier in FIG. FIG. 23 is a diagram showing an example in which the current supply source of each differential amplifier is configured by the same supply current circuit. FIG. 24 is a diagram schematically showing the layout of the light receiving elements and the differential amplifier on the semiconductor substrate in the photoelectric encoder. FIG. 25 is a diagram schematically showing the arrangement of the slits, the light-off portion, and the light receiving element of the moving body in the photoelectric encoder. FIG. 26 is a diagram schematically showing the arrangement of a moving body and light receiving elements in a conventional photoelectric encoder. FIG. 27A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the first embodiment of the present invention. FIG. 27B is a diagram for explaining the configuration of an addition unit and a logical operation unit that calculate the output of the light receiving element of the photoelectric encoder. FIG. 27C is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 28 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 27C. FIG. 29A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the second embodiment of the present invention. FIG. 29B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 30 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 29B. FIG. 31A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the third embodiment of the present invention. FIG. 31B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 32 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 31B. FIG. 33A is a diagram schematically showing the arrangement of the moving bodies and the light receiving elements in the photoelectric encoder according to the fourth embodiment of the present invention. FIG. 33B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 34 is a diagram schematically showing a configuration in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 33B. FIG. 35A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the fifth embodiment of the present invention. FIG. 35B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 36 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 35B. FIG. 37A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the sixth embodiment of the present invention. FIG. 37B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 38 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 37B. FIG. 39A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the seventh embodiment of the present invention. FIG. 39B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder. FIG. 40 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 39B. FIG. 41A is a diagram schematically showing the arrangement of the moving body and the light receiving elements in the photoelectric encoder according to the eighth embodiment of the present invention. FIG. 41B is a diagram showing the arrangement of the moving body and the light receiving element and the output waveform of the photoelectric encoder . FIG. 42 is a diagram schematically showing a form in which dummy photodiodes are arranged between adjacent light receiving elements in FIG. 41B.

DESCRIPTION OF SYMBOLS 10 Semiconductor light receiving chip 11a, 11b, ..., 12a, 12b, ... Light receiving element 20 Light on part corresponding area 21 Light off part corresponding area 40 Moving body 141 Semiconductor light emitting chip 200 Logic operation part X1, X2, ... Light on part Y1, Y2,... Light off section PD01 to PD16,... Light receiving element CP1 to CP8 Comparison section ADD01 to ADD16 Addition section CP1 to CP8 Comparison section PDX Dummy photodiode

Claims (33)

A light emitting element;
A plurality of light receiving elements arranged in one direction in a region where the light from the light emitting element can reach,
A movable body having alternately a light-on portion and a light-off portion that create a state where the light is incident on the light-receiving element and a state where the light is not incident on the light-receiving element at a predetermined position corresponding to each light-receiving element is predetermined. The output of each light receiving element takes a value corresponding to whether light from the light emitting element is incident or not incident on the light receiving element,
The width of each light receiving element in the one direction is equal to or less than ¼ of an input pitch length which is a sum of lengths of the pair of the light on part and the light off part adjacent to the moving body along the one direction. And substantially the same,
The plurality of light receiving elements are divided into a plurality of light receiving element groups each composed of 16 light receiving elements having different phase relationships with respect to a modulation period of incident light due to movement of the moving body,
The plurality of light receiving element groups have 16 sets in which light receiving elements having the same phase relationship with respect to the modulation period of incident light due to the movement of the moving body are combined one by one from the respective light receiving element groups,
For each set consisting of a plurality of light receiving elements having the same phase relationship, an adder that adds and outputs the signals of the plurality of light receiving elements of the same set,
The light receiving element has the same dimensions in the one direction, and has a light on part corresponding region corresponding to the light on part and a light off part corresponding region corresponding to the light off part at a common constant pitch. Are arranged one by one,
The light-receiving elements arranged in the light-on part corresponding region and the light-receiving elements arranged in the light-off part corresponding region have a one-to-one correspondence with the one-to-one correspondence in the arrangement order in the one direction. A comparison unit that takes the difference between the outputs of the element pairs added by the addition unit;
A logic operation unit that performs an operation on a logical value represented by the difference signal obtained by the comparison unit and creates an output signal having a frequency different from the moving frequency;
The comparison unit includes amplifiers corresponding to the light receiving element pairs,
The plurality of amplifiers are arranged side by side in the one direction along a row formed by the plurality of light receiving elements,
A photoelectric encoder, wherein a center position of a row formed by the plurality of light receiving elements and a center position of a row formed by the plurality of amplifiers coincide with each other in the one direction. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups has a width of 1/16 or less of the input pitch length, and is continuously arranged at an interval of 1/16 pitch between the input pitch lengths. As well as
The photoelectric encoder, wherein the plurality of light receiving element groups are arranged along the one direction. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/8 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other at an interval of 1/8 pitch, and the light receiving elements are spaced by 9/16 pitch from the four light receiving elements in the first row. Two rows of four light receiving elements are arranged adjacent to each other,
Four light receiving elements in the third row are arranged adjacent to each other at an interval of 1/8 pitch, and the light receiving elements are spaced apart from each other by 9/16 pitch with respect to the four light receiving elements in the third row. Four light receiving elements in four rows are arranged adjacent to each other,
The third column and the fourth column are 180 ° out of phase with the first column and the second column with respect to the modulation period of incident light due to the movement of the moving body, and
The photoelectric encoder, wherein the plurality of light receiving element groups are arranged along the one direction. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups has a width of 1/8 or less of the input pitch length and is continuously arranged at an interval of 3/16 pitch.
The photoelectric encoder, wherein the plurality of light receiving element groups are arranged along the one direction. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/4 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other at intervals of 1/4 pitch,
The four light receiving elements in the second row are arranged adjacent to each other at a pitch of 1/4 with a pitch of 16/16 with respect to the four light receiving elements in the first row.
The four light receiving elements in the third row are arranged adjacent to each other at a pitch of 1/4 with a pitch of 17/16 with respect to the four light receiving elements in the second row.
The four light receiving elements in the fourth row are arranged adjacent to each other at a quarter pitch with a pitch of 17/16 with respect to the four light receiving elements in the third row,
The photoelectric encoder, wherein the plurality of light receiving element groups are arranged along the one direction. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
The width is 1/4 or less of the input pitch length and is continuously arranged at intervals of 5/16 pitch,
The photoelectric encoder, wherein the plurality of light receiving element groups are arranged along the one direction. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/4 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other at intervals of 1/4 pitch,
On the same line where the first row is arranged along the one direction, the four light receiving elements in the second row are spaced apart from each other by a quarter pitch of 17/16 with respect to the four light receiving elements in the first row. Are arranged adjacent to each other,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the same line in which the first row and the second row are arranged along the one direction, an interval of ¼ pitch. The four light receiving elements in the third row are arranged adjacent to each other,
On the same line in which the third row is arranged along the one direction, the four light receiving elements in the fourth row are spaced by 1/16 pitch with a pitch of 17/16 with respect to the four light receiving elements in the third row. Are arranged adjacent to each other,
The eight light receiving elements in the first and second rows and the eight light receiving elements in the third and fourth rows are 1/8 pitch with respect to the modulation period of incident light due to the movement of the moving body. A photoelectric encoder having a phase difference of The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/8 or less of the input pitch length, and
The eight light receiving elements in the first row are arranged adjacent to each other at an interval of 1/8 pitch,
The second row is spaced at 1/8 pitch on the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the same line arranged along the one direction. Are arranged adjacent to each other,
The eight light receiving elements in the first row and the eight light receiving elements in the second row have a phase difference of 1/16 pitch with respect to the modulation period of incident light due to the movement of the moving body. A photoelectric encoder. The photoelectric encoder according to claim 1,
Each of the 16 light receiving elements of the plurality of light receiving element groups is:
A width of 1/4 or less of the input pitch length, and
Four light receiving elements in the first row are arranged adjacent to each other on the same line along the one direction at intervals of 1/4 pitch,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the line arranged along the one direction, the second row is spaced at 1/4 pitch. Four light receiving elements are arranged adjacent to each other,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the line on which the first row and the second row are arranged along the one direction at intervals of 1/4 pitch. Four light receiving elements in the third row are arranged adjacent to each other,
On the line along the one direction shifted in the direction perpendicular to the moving direction of the moving body from the line on which the first, second, and third columns are arranged along the one direction, ¼ Four light receiving elements in the fourth row are arranged adjacent to each other at pitch intervals, and
The four light receiving elements in the first row and the four light receiving elements in the second row have a phase difference of 1/16 pitch with respect to the modulation period of incident light due to the movement of the moving body,
The four light receiving elements in the first row and the four light receiving elements in the third row have a phase difference of 1/8 pitch with respect to the modulation period of incident light due to the movement of the moving body,
The four light receiving elements in the first row and the four light receiving elements in the fourth row have a phase difference of 3/16 pitch with respect to a modulation period of incident light due to movement of the moving body. A photoelectric encoder. The photoelectric encoder according to any one of claims 1 to 9,
A photoelectric encoder, wherein a dummy photodiode serving as an inactive region with respect to input light is disposed between the light receiving elements adjacent to each other. The photoelectric encoder according to any one of claims 1 to 9,
For each set of light receiving elements, based on the output of the adder that adds the signals of the plurality of light receiving elements of the same set, A comparison unit that takes a difference signal between the outputs of the pair of light receiving elements in which the outputs correspond to one to one;
The photoelectric encoder according to claim 1, wherein the logical operation unit performs a logical operation on a logical value represented by the difference signal obtained by the comparison unit. The photoelectric encoder according to any one of claims 1 to 9,
The photoelectric encoder according to claim 1, wherein the frequency of the output signal generated by the logical operation unit is an integral multiple of the moving frequency. The photoelectric encoder according to any one of claims 1 to 9,
A photoelectric encoder, wherein a duty ratio of an output signal generated by the logic operation unit is different from a duty ratio of an output of each light receiving element. The photoelectric encoder according to any one of claims 1 to 9,
The photoelectric encoder characterized in that the light-on part and the light-off part of the moving body have the same dimensions in the one direction. The photoelectric encoder according to any one of claims 1 to 9,
The photoelectric encoder is characterized in that the logical operation unit takes an exclusive OR of logical values obtained from the output of the addition unit. The photoelectric encoder according to any one of claims 1 to 9,
The photoelectric operation unit, wherein the logical operation unit takes exclusive OR of logical values obtained from the output of the addition unit a plurality of times. The photoelectric encoder according to any one of claims 1 to 9,
The photoelectric encoder is characterized in that the logical operation part takes an exclusive OR of logical values obtained from the output of the addition part, and further takes a logical product or a negative logical product. The photoelectric encoder according to claim 17,
The logical operation unit generates an exclusive OR of the logical values obtained from the output of the addition unit to generate a plurality of signals having a duty ratio of 3/4, and a logical product or a negative logical product of the signals. To obtain a signal having a duty ratio of 1/2. The photoelectric encoder according to any one of claims 1 to 9,
The photoelectric operation unit includes an integrated injection logic element, and performs the operation using the integrated injection logic element. The photoelectric encoder according to any one of claims 1 to 9,
A plurality of the light receiving elements are arranged in a light on part corresponding region corresponding to the light on part of the moving body with respect to the one direction. The photoelectric encoder according to claim 20,
A plurality of light receiving elements arranged in the light-on-corresponding region have the same dimensions in the one direction and are arranged at a constant pitch. The photoelectric encoder according to claim 1,
The comparison unit includes logarithmic amplifiers corresponding to the light receiving element pairs,
Each of the logarithmic amplifiers logarithmically amplifies a difference between outputs of corresponding light receiving element pairs. The photoelectric encoder according to claim 1,
The comparison unit includes amplifiers corresponding to the light receiving element pairs,
A photoelectric encoder comprising the same supply current circuit for supplying a current to each of the amplifiers. The photoelectric encoder according to claim 1,
The comparison unit is configured to use, as a reference input, an output of a light receiving element arranged in the light-off part corresponding region in each light receiving element pair. The photoelectric encoder according to any one of claims 1 to 9,
The logical operation unit divides signals obtained from a plurality of light receiving elements arranged in the light on part corresponding region corresponding to the light on part of the moving body into a plurality of groups based on the arrangement order of the plurality of light receiving elements. And a plurality of output signals having different phases from each other to obtain a photoelectric encoder. The photoelectric encoder according to claim 25,
The logical operation unit periodically divides signals obtained from a plurality of light receiving elements arranged in the light-on part corresponding region into a plurality of groups according to an arrangement order of the one light receiving element in the one direction. Characteristic photoelectric encoder. The photoelectric encoder according to claim 26,
The photoelectric operation unit, wherein the logical operation unit divides a signal obtained from a plurality of light receiving elements arranged in the light-on unit corresponding region into two groups. The photoelectric encoder according to any one of claims 1 to 9,
A plurality of light receiving elements arranged in the light-on-corresponding region are arranged at a constant pitch with respect to the one direction, and each of the light-receiving elements is arranged on a line obtained by dividing the light-on-corresponding region at equal intervals. A photoelectric encoder characterized in that the ends are arranged correspondingly. The photoelectric encoder according to claim 28,
The light receiving element is arranged in k (k is a natural number of 2 or more) in the light on part corresponding region corresponding to the light on part of the moving body with respect to the one direction. Encoder. The photoelectric encoder according to claim 29,
Said k is 3 or more, the logical operation unit, characterized by taking exclusive OR in addition in the order of the logical value, the light receiving element is adjacent with respect to the one direction represented by the output signal of the light receiving element A photoelectric encoder. The photoelectric encoder according to claim 29,
K is 3 or more, and the logic operation unit alternately outputs a logical value represented by the output of the light receiving element from the light receiving elements arranged at both ends in the light on portion corresponding region in the one direction. photoelectric encoder, characterized by taking exclusive OR with added arranged sequentially toward the light receiving element. The photoelectric encoder according to any one of claims 1 to 9,
The logic operation unit divides signals obtained from a plurality of light receiving elements arranged in the light on part corresponding region corresponding to the light on part of the moving body into two groups having phases different from each other by 90 °. A photoelectric encoder characterized by taking an exclusive OR of signals having phases different from each other by 90 °.   An electronic device comprising the photoelectric encoder according to any one of claims 1 to 32.

Images