JP2017107132A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device that allows range-finding based on a TOF measuring method and range-finding based on a phase difference detection method to be used.SOLUTION: An electronic device comprises: an imaging unit that includes a first pixel receiving light from a subject, passing through a first pupil area of an optical system, and outputting a first signal, and a second pixel receiving light from the subject, passing through a second pupil area different from the first pupil area, and outputting a second signal; a first range-finding unit that measures a distance to the subject on the basis of a deviation between an image of the subject of the first pupil area received by the first pixel and an image of the subject of the second pupil area received by the second pixel; a light source unit that emits light with which the subject is irradiated; and a second range-finding unit that detects a time until light reception in the first pixel from light emitting in the light source unit on the basis of the first signal output by the first pixel receiving the light reflected upon the subject of the light, and measures a distance to the subject.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an electronic device.

  An optical time-of-flight (TOF) measurement method is known in which a distance to an object is measured by receiving reflected light of light irradiated on the object (for example, Patent Document 1). In the TOF measurement method, there is a known problem that the accuracy of distance measurement is lowered depending on the environment.

Japanese Patent No. 5395323

  An electronic apparatus according to the present invention includes a first pixel that receives light from a subject that has passed through a first pupil region of an optical system and outputs a first signal, and a second pupil that is different from the first pupil region. A second pixel that receives light from a subject that has passed through the region and outputs a second signal; and an image of the subject in the first pupil region received by the first pixel and the second pixel. A first distance measuring unit that measures the distance to the subject based on the deviation of the second pupil region from the subject image, a light source unit that emits light to irradiate the subject, and light reflected by the subject A second distance measuring unit that detects a time from light emission at the light source unit to light reception at the first pixel based on a first signal output by the first pixel that has received light, and measures a distance to the subject; Prepare.

It is sectional drawing which shows typically the structure of the imaging device which concerns on 1st Embodiment. 3 is a block diagram schematically showing a configuration of an imaging unit 12. FIG. It is a top view which shows typically the structure of the horizontal block 21a. It is a figure which shows the circuit structure of the non-ranging pixel 301 and the 1st ranging pixel 302a. It is a figure which shows the circuit structure of the receiving circuit 53 which the control part 13 has. It is a figure which shows typically the structure of the pixel 301 for non ranging. It is a figure which shows typically the structure of the pixel 302a for 1st ranging, and the pixel 302b for 2nd ranging. It is a top view which shows typically the structure of the vertical block 21b. 6 is a flowchart of a focus adjustment process executed by a control unit 13; 3 is a plan view schematically showing a part of an imaging surface of an imaging unit 12. FIG. It is an enlarged view of the 1st pixel 303a. 6 is a diagram illustrating a modification of the reception circuit 53. FIG.

(First embodiment)
FIG. 1 is a cross-sectional view schematically showing the configuration of the imaging apparatus according to the first embodiment. The imaging device 1 includes a light source unit 10, an imaging optical system 11, an imaging unit 12, and a control unit 13.

  The light source unit 10 emits the measurement light beam 3 to the object to be measured 2. The measurement light beam 3 is, for example, visible light. Note that the measurement light beam 3 may be infrared light. Of the measurement light beam 3, the reflected light beam 4 reflected by the surface of the DUT 2 passes through the imaging optical system 11 and enters the imaging unit 12. The imaging unit 12 is, for example, a backside illumination type CMOS image sensor.

  The control unit 13 includes a CPU (not shown) and its peripheral circuits. The control unit 13 controls the entire imaging apparatus 1 by reading and executing a predetermined control program. The control unit 13 includes a first distance measuring unit 13a, a second distance measuring unit 13b, a photometric unit 13c, and a focus adjusting unit 13d. Each of these units included in the control unit 13 is realized by software by the control program. In addition, you may comprise these each part which the control part 13 has with the electronic circuit etc. which have an equivalent function.

  The first distance measuring unit 13a and the second distance measuring unit 13b measure the distance to the device under test 2 based on the photoelectric conversion signal output from the imaging unit 12. The first distance measuring unit 13a and the second distance measuring unit 13b perform distance measurement using different methods. The photometry unit 13 c measures the object to be measured 2 based on the photoelectric conversion signal output from the imaging unit 12. Note that an optical sensor or the like that is different from the imaging unit 12 may be provided in the imaging device 1, and the photometric unit 13c may measure the measured object 2 based on the output of the optical sensor or the like. The focus adjustment unit 13d performs focus adjustment of the imaging optical system 11.

  FIG. 2 is a block diagram schematically illustrating the configuration of the imaging unit 12. The imaging surface 20 of the imaging unit 12 includes a total of 24 blocks 21 of 6 × 4. Five imaging areas 22 are provided on the imaging surface 20. Three of the five distance measuring areas 22 are horizontally long distance measuring areas 22a, and the other two are vertically long distance measuring areas 22b. The first distance measurement unit 13 a and the second distance measurement unit 13 b perform distance measurement for each of the five distance measurement regions 22.

  Each of the 24 blocks 21 includes a part of one of the ranging areas 22. Of the 24 blocks 21, 16 are the horizontal blocks 21a including a part of the horizontally long distance measuring area 22a. The remaining eight are vertical blocks 21b including a part of the vertically long ranging area 22b.

  The imaging unit 12 includes a horizontal scanning circuit 23 and a vertical scanning circuit 24. For each block 21, the horizontal scanning circuit 23 and the vertical scanning circuit 24 scan the imaging pixels included in the block 21 and read out the photoelectric conversion signal.

  FIG. 3 is a plan view schematically showing the configuration of the horizontal block 21a. In the horizontal block 21a, a plurality of imaging pixels 30 are arranged two-dimensionally. The plurality of imaging pixels 30 include three types of pixels: a non-distance measuring pixel 301, a first distance measuring pixel 302a, and a second distance measuring pixel 302b. In the horizontally long ranging area 22a, the first ranging pixels 302a and the second ranging pixels 302b are alternately arranged in the lateral direction (x direction). Non-distance measuring pixels 301 are arranged at other locations.

  In the plurality of imaging pixels 30 arranged in the horizontal block 21a, when the photoelectric conversion signal is read out, the first row is first read out simultaneously, and then the second and subsequent rows are read out sequentially. Accordingly, the photoelectric conversion signals read from the first distance measurement pixel 302a and the second distance measurement pixel 302b in the horizontally long distance measurement area 22a have simultaneity.

  FIG. 4 is a diagram illustrating a circuit configuration of the non-distance measuring pixel 301 and the first distance measuring pixel 302a. The non-distance measuring pixel 301 includes a photodiode PD, a transfer transistor TX, a reset transistor RST, a selection transistor SEL, and an amplification transistor AMP.

  The photodiode PD photoelectrically converts incident light to generate a signal charge. The generated signal charge is transferred to the floating diffusion FD via the transfer transistor TX. The amplification transistor AMP outputs a signal corresponding to the amount of signal charge accumulated in the floating diffusion FD to the selection transistor SEL. When the vertical scanning circuit 24 turns on the selection transistor SEL, a signal corresponding to the amount of signal charge accumulated in the floating diffusion FD is output to the control unit 13. The signal charge transferred to the floating diffusion FD is reset by turning on and off the reset transistor RST.

  In the following description, a part including the transfer transistor TX, the selection transistor SEL, and the amplification transistor AMP is referred to as an output unit 50 for convenience. The output unit 50 outputs a photoelectric conversion signal from the photodiode PD to the control unit 13. The control unit 13 has one receiving circuit 53 for each column. The receiving circuit 53 is a circuit that receives the photoelectric conversion signal output from the output unit 50. The configuration of the receiving circuit 53 will be described in detail later.

  The first ranging pixel 302a includes a photodiode PDa, a first transfer transistor TX1, a first reset transistor RST1, a first selection transistor SEL1, a first amplification transistor AMP1, a second transfer transistor TX2, a second reset transistor RST2, A two-select transistor SEL2 and a second amplification transistor AMP2 are included.

  The first transfer transistor TX1, the first reset transistor RST1, the first selection transistor SEL1, and the first amplification transistor AMP1 are respectively the transfer transistor TX, the reset transistor RST, the selection transistor SEL, and the amplification that the non-ranging pixel 301 has. Works the same as the transistor AMP. The same applies to the second transfer transistor TX2, the second reset transistor RST2, the second selection transistor SEL2, and the second amplification transistor AMP2.

  That is, the first ranging pixel 302 a has two sets of circuits corresponding to the output unit 50 of the non-ranging pixel 301. In the following description, for convenience, a portion including the first transfer transistor TX1, the first selection transistor SEL1, and the first amplification transistor AMP1 is referred to as a first output unit 51, and the second transfer transistor TX2, the second selection transistor SEL2, and A portion including the second amplification transistor AMP2 is referred to as a second output unit 52. The first ranging pixel 302a is configured to be able to separately read out the signal charge generated by the photodiode PDa from the first output unit 51 and the second output unit 52.

  The control unit 13 has two receiving circuits 53 for each column for the column including the first ranging pixel 302a or the second ranging pixel 302b. One receiving circuit 53 is a circuit that receives the photoelectric conversion signal output from the first output unit 51. The other receiving circuit 53 is a circuit that receives the photoelectric conversion signal output from the second output unit 52.

  Note that the circuit configuration of the second ranging pixel 302b is the same as that of the first ranging pixel 302a, and thus the description thereof is omitted.

  FIG. 5 is a diagram illustrating a circuit configuration of the reception circuit 53 included in the control unit 13. The receiving circuit 53 removes noise components from the received photoelectric conversion signal by correlated double sampling (CDS). The receiving circuit 53 converts the photoelectric conversion signal from which the noise component is removed into a digital value. The receiving circuit 53 outputs a digital value obtained by converting the photoelectric conversion signal.

  The receiving circuit 53 clamps the feedthrough period immediately after the imaging pixel 30 is reset by the switch 531 on the upper side of the drawing. The receiving circuit 53 clamps the output period of the photoelectric conversion signal with the switch 532 on the lower side of the drawing. Thereafter, the receiving circuit 53 turns on the switch 533 and the switch 534, inputs the clamped voltage to the differential amplifier 535, and obtains the difference between the two voltages. The receiving circuit 53 converts the output of the differential amplifier 535 into a 12-bit digital value by the AD converter 536 and outputs the digital value. As described above, the control unit 13 can read out a digital value from which amplifier noise and reset noise are removed as a pixel value.

  6A is a cross-sectional view schematically showing the configuration of the non-distance measuring pixel 301, and FIG. 6B is a plan view schematically showing the configuration of the non-distance measuring pixel 301. The upper side of the drawing in FIG. 6A is the incident surface of the light beam from the DUT 2. That is, the light beam from the DUT 2 enters from the upper side of the drawing in FIG. 6A toward the lower side of the drawing. The lowermost layer of the imaging unit 12 is a wiring layer 40. On the wiring layer 40, a silicon substrate 41 and a microlens 43 are arranged in this order.

  On the silicon substrate 41, a photodiode PD, a source / drain electrode 45, and a pixel separation structure 46 are formed. The pixel separation structure 46 is a structure that electrically separates the non-distance measuring pixels 31 from each other. The pixel isolation structure 46 is, for example, so-called STI (shallow trench isolation). The source / drain electrode 45 is a source electrode or a drain electrode of the transfer transistor TX shown in FIG.

  A gate electrode 47 and a wiring 48 are formed in the wiring layer 40. The gate electrode 47 is the gate electrode of the transfer transistor TX shown in FIG. The wiring 48 is a wiring constituting each circuit of the non-distance measuring pixel 301.

  The light beam from the DUT 2 passes through the microlens 43 and enters the photodiode PD formed in the silicon substrate 41. The photodiode PD generates an amount of signal charge corresponding to the amount of incident light flux. As shown in FIG. 6B, the surface area of the photodiode PD is increased as much as possible in order to increase the light collection efficiency. The photodiode PD configured as described above receives the light beam that has passed through the entire exit pupil of the imaging optical system 11.

  FIG. 7A is a cross-sectional view schematically showing the configuration of the first ranging pixel 302a and the second ranging pixel 302b, and FIG. 7B shows the first ranging pixel 302a and the second ranging pixel 302a. It is a top view which shows typically the structure of the pixel 302b for 2 ranging.

  The first ranging pixel 302a includes a microlens 43a and a photodiode PDa. As shown in FIG. 6B, the photodiode PDa is arranged to be biased to the right half of the microlens 43a. A light shielding member 42 is disposed between the microlens 43 a and the silicon substrate 41. The light shielding member 42 is disposed so as to cover the left half of the microlens 43a.

  The photodiode PDa configured as described above receives a light beam that has passed through a part of the pupil region (a pupil region corresponding to the right half of the microlens 43a) of the entire exit pupil of the imaging optical system 11. The light beam that has passed through the remaining region is blocked by the light shielding member 42 and does not reach the photodiode PDa.

  On the silicon substrate 41, a photodiode PDa, a source / drain electrode 45, and a pixel separation structure 46 are formed. The source / drain electrodes 45 are the source and drain electrodes of the transfer transistors TX1 and TX2 shown in FIG.

  In the wiring layer 40, gate electrodes 471 and 472 and a wiring 48a are formed. The gate electrode 471 is the gate electrode of the transfer transistor TX1 shown in FIG. The gate electrode 472 is the gate electrode of the transfer transistor TX2 shown in FIG. The wiring 48a is a wiring configuring each circuit of the first distance measuring pixel 302a.

  Both the gate electrodes 471 and 472 and the wiring 48 a are disposed below the light shielding member 42. Therefore, the light beam that has passed through the microlens 43a does not reach these parts. Thereby, these each part is not influenced by the photoelectric effect.

  The second ranging pixel 302b includes a microlens 43b and a photodiode PDb. As shown in FIG. 6B, the photodiode PDb is arranged to be biased to the left half of the microlens 43b. A light blocking member 42 is disposed between the microlens 43 b and the silicon substrate 41. The light shielding member 42 is disposed so as to cover the right half of the microlens 43b.

  The photodiode PDb configured as described above receives a light beam that has passed through a part of the pupil area (an area corresponding to the left half of the microlens 43b) of the entire exit pupil of the imaging optical system 11. The light beam that has passed through the remaining region is blocked by the light shielding member 42 and does not reach the photodiode PDb.

  On the silicon substrate 41, a photodiode PDb, source / drain electrodes 45, and a pixel separation structure 46 are formed. The source / drain electrodes 45 are the source and drain electrodes of the transfer transistors TX1 and TX2 shown in FIG.

  In the wiring layer 40, gate electrodes 473 and 474 and a wiring 48b are formed. The gate electrode 473 is a gate electrode of the transfer transistor TX1 shown in FIG. The gate electrode 474 is a gate electrode of the transfer transistor TX2 shown in FIG. The wiring 48b is a wiring that constitutes each circuit of the second ranging pixel 302b.

  The gate electrodes 473 and 474 and the wiring 48 b are both disposed below the light shielding member 42. Therefore, the light beam that has passed through the microlens 43b does not reach these parts. Thereby, these each part is not influenced by the photoelectric effect.

  FIG. 8 is a plan view schematically showing the configuration of the vertical block 21b. In the vertical block 21b, a plurality of imaging pixels 30 are arranged two-dimensionally. The plurality of imaging pixels 30 include three types of pixels: a non-distance measuring pixel 301, a third distance measuring pixel 302c, and a fourth distance measuring pixel 302d. In the vertically long ranging area 22b, the third ranging pixels 302c and the fourth ranging pixels 302d are alternately arranged in the vertical direction (y direction). Non-distance measuring pixels 301 are arranged at other locations.

  In the plurality of imaging pixels 30 arranged in the vertical block 21b, when reading out the photoelectric conversion signal, the first column is first read out simultaneously, and then the second column and thereafter are sequentially read out. Therefore, the photoelectric conversion signals read from the third distance measurement pixel 302c and the fourth distance measurement pixel 302d in the vertically long distance measurement area 22b have simultaneity.

  The third ranging pixel 302c has a configuration in which the first ranging pixel 302a on the xy plane is rotated 90 degrees clockwise. That is, the third ranging pixel 302c has a microlens and a photodiode. The photodiode is biased to the lower half of the microlens. The third ranging pixel 302c has a light shielding member disposed so as to cover the upper half of the microlens. Therefore, the photodiode included in the third distance measurement pixel 302c is a partial pupil region (not the first distance measurement pixel 302a and the second distance measurement pixel 302b) of the entire exit pupil of the imaging optical system 11. The light beam that has passed through the pupil region corresponding to the lower half of the microlens is received.

  The fourth ranging pixel 302d has a configuration in which the second ranging pixel 302b on the xy plane is rotated 90 degrees clockwise. That is, the fourth ranging pixel 302d has a microlens and a photodiode. The photodiode is biased to the upper half of the microlens. The fourth ranging pixel 302d has a light shielding member arranged so as to cover the lower half of the microlens. Accordingly, the photodiodes included in the fourth distance measurement pixel 302d are the first distance measurement pixel 302a, the second distance measurement pixel 302b, the third distance measurement pixel 302c of the entire exit pupil of the imaging optical system 11. A light beam that has passed through a part of the pupil region (a pupil region corresponding to the upper half of the microlens) is received.

(Description of distance measurement by the phase difference detection method by the first distance measuring unit 13a)
A distance measuring operation by the first distance measuring unit 13a will be described. In the following description, one of the horizontally long ranging areas 22a will be described as an example. The vertical distance measurement area 22b has the same operation except that the distance measurement direction and the readout direction are the vertical direction, and thus description thereof is omitted.

  The first distance measuring unit 13a performs distance measurement using a so-called phase difference detection method. The first distance measuring unit 13 a reads out a photoelectric conversion signal from each of the first distance measuring pixels 302 a arranged in the horizontal direction every other pixel via the first output unit 51. The plurality of photoelectric conversion signals read out here are set as a signal string a (i). The first distance measuring unit 13 a reads out a photoelectric conversion signal from each of the second distance measuring pixels 302 b arranged in the horizontal direction every other pixel via the first output unit 51. The plurality of photoelectric conversion signals read out here are set as a signal string b (i). The exposure timing and readout timing for generating the signal sequence a (i) and the signal sequence b (i) are the same.

  The first distance measuring unit 13a performs correlation calculation based on the signal sequence a (i) and the signal sequence b (i), and detects a shift (phase difference) between the signal sequence a (i) and the signal sequence b (i). . Then, the distance to the DUT 2 is calculated by multiplying this deviation (phase difference) by a predetermined coefficient.

  The signal sequence a (i) may be read using the second output unit 52. Similarly, the signal sequence b (i) may be read using the second output unit 52.

  The first distance measuring unit 13a can also read the photoelectric conversion signal from the third distance measuring pixel 302c and the fourth distance measuring pixel 302d and calculate the distance to the DUT 2. Since the first distance measurement pixel 302a and the second distance measurement pixel 302b are arranged in the horizontal direction, the distance measurement is performed based on a shift (phase difference) in the horizontal direction of the DUT 2. On the other hand, since the third distance measurement pixel 302c and the fourth distance measurement pixel 302d are arranged in the vertical direction, distance measurement is performed based on a shift (phase difference) in the vertical direction of the DUT 2.

(Description of distance measurement of the TOF measurement method by the second distance measuring unit 13b)
A distance measuring operation by the second distance measuring unit 13b will be described. In the following description, one of the horizontally long ranging areas 22a will be described as an example. The vertical distance measurement area 22b has the same operation except that the distance measurement direction is the vertical direction, and a description thereof will be omitted.

  The second distance measuring unit 13b performs distance measurement using a so-called TOF measurement method. During distance measurement by the second distance measuring unit 13 b, the light source unit 10 emits the measurement light beam 3 to the object to be measured 2. The measurement light beam 3 is pulsed light having a predetermined width. That is, the light source unit 10 emits light having a constant intensity for a predetermined period.

  The measurement light beam 3 emitted from the light source unit enters the first distance measurement pixel 302a as a reflected light beam 4. The second distance measuring unit 13b reads out the photoelectric conversion signal via the first output unit 51 of the first distance measuring pixel 302a at a predetermined time. The second distance measuring unit 13b then reads out the photoelectric conversion signal via the second output unit 52 of the first distance measuring pixel 302a. That is, the second distance measuring unit 13b divides the photoelectric conversion signals for a certain period by the first distance measuring pixels 302a into periods before and after a predetermined time as a boundary and reads them separately.

  The second distance measurement unit 13b is configured to output the photoelectric conversion signal read from the first output unit 51 and the photoelectric conversion signal read from the second output unit 52 for the same first distance measurement pixel 302a. The ratio with the signal amount is calculated. The second distance measuring unit 13b calculates the delay time of the reflected light beam 4 from the calculated ratio. The delay time of the reflected light beam 4 is the time from when the measurement light beam 3 starts from the light source unit 10 until it is reflected by the surface of the object 2 to be measured and becomes the reflected light beam 4 and reaches the imaging unit 12. The second distance measuring unit 13b calculates the distance to the DUT 2 from this delay time and the known speed of light.

  The second distance measuring unit 13b can also measure the distance of the DUT 2 similarly for the second distance measuring pixel 302b, the third distance measuring pixel 302c, and the fourth distance measuring pixel 302d. . Since the specific distance measurement procedure is the same as that of the first distance measurement pixel 302a described above, the description thereof is omitted.

(Explanation of focus adjustment process)
FIG. 9 is a flowchart of the focus adjustment process executed by the control unit 13. In step S100, the photometry unit 13c performs photometry on the DUT 2. In step S110, the focus adjustment unit 13d determines whether or not the light amount that is the photometric result of the DUT 2 exceeds a predetermined threshold value. If the amount of light exceeds a predetermined threshold value, that is, if the amount of light is large, the focus adjusting unit 13d advances the process to step S120.

  In step S120, the first distance measurement unit 13a receives photoelectric conversion signals from the first output parts 51 of the first distance measurement pixels 302a and the second distance measurement pixels 302b arranged in the five distance measurement regions 22. read out. By this readout, five signal sequences a (i) and b (i) corresponding to each of the five distance measurement areas 22 are created. In step S130, the first distance measuring unit 13a detects a shift (phase difference) between each of the five signal sequences a (i) and b (i). In step S <b> 140, the first distance measuring unit 13 a calculates the distance of the DUT 2 corresponding to each of the five distance measurement areas 22 from the shift (phase difference) corresponding to each of the five distance measurement areas 22. .

  If the light amount does not exceed the predetermined threshold value in step S110, the focus adjusting unit 13d advances the process to step S150. In step S150, the second distance measuring unit 13b causes the light source unit 10 to emit the measurement light beam 3. In step S160, the second distance measuring unit 13b receives a photoelectric conversion signal from the first output unit 51 of the first distance measuring pixel 302a and the second distance measuring pixel 302b arranged in the five distance measuring regions 22. read out. In step S170, the second distance measuring unit 13b receives a photoelectric conversion signal from the second output unit 52 of the first distance measuring pixel 302a and the second distance measuring pixel 302b arranged in the five distance measuring regions 22. read out.

  In step S <b> 180, the second ranging unit 13 b for each of the five ranging areas 22, the signal amount of the photoelectric conversion signal read from the first output unit 51 and the photoelectric conversion signal read from the second output unit 52. Based on the ratio to the signal amount, the delay time of the measurement light beam 3 is calculated. In step S <b> 190, the second distance measuring unit 13 b calculates the distance of the DUT 2 corresponding to each of the five distance measurement areas 22 based on the delay time corresponding to each of the five distance measurement areas 22.

  In step S200, the focus adjustment unit 13d performs focus adjustment of the imaging optical system 11 based on the distance of the DUT 2 calculated in step S140 or the distance of the DUT 2 calculated in step S190. Since the distance of the DUT 2 is calculated for each of the five distance measurement areas 22, the focus adjustment unit 13d selects, for example, one distance measurement area 22 that is the object of focus adjustment, or five measurement areas. Focus adjustment is performed by determining the final target distance from the distance calculated for each of the distance regions 22.

According to the imaging apparatus according to the first embodiment described above, the following operational effects can be obtained.
(1) The photodiode PDa of the first ranging pixel 302a receives the light beam that has passed through the first pupil region, which is a partial region of the exit pupil of the imaging optical system 11, and outputs a first signal. The photodiode PDb of the second ranging pixel 302b receives the light beam that has passed through the second pupil region, which is another part of the exit pupil of the imaging optical system 11, and outputs a second signal. The first distance measuring unit 13a measures the distance to the DUT 2 based on the shift (phase difference) between the first signal and the second signal. The second distance measuring unit 13b is based on the first signal output by the photodiode PDa that has received the light beam reflected by the DUT 2 and passing through the first pupil region out of the measurement light beam 3 emitted from the light source unit 10. The delay time from the emission of the measurement light beam 3 to the light reception is detected to measure the distance to the object to be measured. Since it did in this way, ranging based on the TOF measurement method and ranging based on the phase difference detection method can be used together. In particular, since the image pickup unit 12 can be a single image pickup device, it is possible to obtain flexibility in which two types of distance measurement can be used together without increasing the number of components.

(2) The imaging unit 12 includes a first output unit 51 that outputs a first signal based on a light beam received by the photodiode PDa between a first time and a second time, and a second time to a third time. And a second output unit 52 for outputting a first signal based on the light beam received by the photodiode PDa. Based on the first signal output from the first output unit 51 and the first signal output from the second output unit 52, the second distance measuring unit 13b detects a delay time from the emission of the measurement light beam 3 to the light reception. To do. Since it did in this way, in the situation where the phase difference detection method is not suitable, distance measurement based on the TOF measurement method can be performed, and flexible distance measurement according to the situation can be performed.

(3) The second distance measuring unit 13b includes a first signal based on the light beam received from the first time to the second time and a first signal based on the light beam received from the second time to the third time. Based on the signal amount difference from the signal, the delay time from the emission of the measurement light beam 3 to the light reception is detected. Since it did in this way, in the situation where the phase difference detection method is not suitable, distance measurement based on the TOF measurement method can be performed, and flexible distance measurement according to the situation can be performed.

(4) When the amount of light measured by the photometry unit 13c is greater than or equal to a predetermined amount, the focus adjustment unit 13d adjusts the focus of the imaging optical system 11 based on the measurement result by the first distance measurement unit 13a, and the photometry unit 13c When the amount of light measured by the above is less than a predetermined amount, focus adjustment of the imaging optical system 11 is performed based on the measurement result by the second distance measuring unit 13b. Since it did in this way, reliable focus adjustment can be performed irrespective of the light quantity of environmental light.

(5) The imaging unit 12 includes a first distance measurement pixel 302a including the microlens 43 and the photodiode PDa, and a second distance measurement different from the first distance measurement pixel 302b including the microlens 43 and the photodiode PDb. And a distance pixel 302b. Since it did in this way, the 1st ranging part 13a can perform what is called a phase difference type distance measurement.

(6) The first ranging pixel 302a has a light shielding member 42 that shields the light beam that has passed through a region different from the first region of the exit pupil, and the second ranging pixel 302b has a second exit pupil. A light shielding member 42 that shields a light beam that has passed through an area different from the area is provided. Since it did in this way, it is prevented that the photodiode PDa receives the light beam which passed the area | regions other than 1st area | region, and the photodiode PDb received the light beam which passed the area | regions other than the 2nd area | region.

(7) The first output unit 51 and a part of the second output unit 52 are arranged in a range where the light is shielded by the light shielding member 42 of the first distance measurement pixel 302a. Since it did in this way, the 1st output part 51 and the 2nd output part 52 are not influenced by the photoelectric effect. In addition, the space occupied by the first ranging pixels 302a can be used effectively.

(8) The imaging unit 12 receives a light beam that has passed through a third region that is a partial region of the exit pupil that is different from the first region and the second region, and has a photodiode that outputs a third signal. A fourth distance measuring device having a distance pixel 302c and a photodiode that receives a light beam that has passed through a fourth region that is a partial region of an exit pupil different from any of the first to third regions and outputs a fourth signal. And a pixel for use 302d. The direction in which the photodiode PDa and the photodiode PDb are arranged side by side is different from the direction in which the photodiode of the third ranging pixel 302c and the photodiode of the fourth ranging pixel 302d are arranged side by side. Since it did in this way, the ranging of the to-be-measured object 2 can be performed about a mutually different direction.

(9) The first distance measuring unit 13a performs distance measurement based on the phase difference detection method. The distance measurement based on the phase difference detection method can be performed without emitting the measurement light beam 3 from the light source unit 10, so that the power consumed by the emission of the measurement light beam 3 by the light source unit 10 can be saved.

(10) The second distance measuring unit 13b performs distance measurement based on the TOF measurement method. The distance measurement based on the TOF measurement method is performed using the measurement light beam 3 emitted from the light source unit 10, so that the distance measurement can be accurately performed even in a dark environment.

(Second Embodiment)
In the first embodiment described above, the distance measurement by the second distance measuring unit 13b is performed only in the area where the distance measurement pixels 302 are arranged. The imaging apparatus according to the second embodiment includes an imaging unit 12 that can perform ranging by the first distance measuring unit 13a and the second distance measuring unit 13b in all regions on the imaging surface. In the following description, the same portions as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 10 is a plan view schematically showing a part of the imaging surface of the imaging unit 12. Pixels 303 are two-dimensionally arranged on the imaging surface of the imaging unit 12. The pixel 303 includes four types of a first pixel 303a, a second pixel 303b, a third pixel 303c, and a fourth pixel 303d.

  The shape of the pixel 303 is a square. The pixels 303 are two-dimensionally arranged on the xy plane with the square rotated 45 degrees. In the column 121, the first pixels 303a and the second pixels 303b are alternately arranged (every other pixel). In the column 122 adjacent to the column 121, the third pixels 303c and the fourth pixels 303d are alternately arranged (every other pixel).

  FIG. 11 is an enlarged view of the first pixel 303a. The first pixel 303a includes a microlens 43 having a square shape and a photodiode PD having a right triangle shape. The photodiode PD is arranged to occupy the left half region of the first pixel 303a. In the remaining right half of the first pixel 303a, the gate electrode 47 of the transfer transistor and the wiring 48 are arranged. A light shielding member 42 covering the gate electrode 47 and the wiring 48 is disposed on the right half of the first pixel 303a. Due to the light shielding member 42, the reflected light beam 4 does not enter the gate electrode 47 and the wiring 48.

  The circuit configuration of the first pixel 303a is the same as that of the non-distance measuring pixel 301 shown in FIG. That is, the first pixel 303 a does not have the two output units 51 and 52 like the ranging pixel 302 but has only a single output unit 50.

  The second pixel 303b is a pixel obtained by rotating the first pixel 303a clockwise by 180 degrees. Similarly, the third pixel 303c is a pixel obtained by rotating the first pixel 303a by 90 degrees clockwise, and the fourth pixel 303d is a pixel obtained by rotating the first pixel 303a by 270 degrees clockwise.

  A distance measuring operation by the first distance measuring unit 13a will be described. The first distance measuring unit 13a of the present embodiment can perform distance measurement in the vertical direction, the horizontal direction, and the oblique direction at an arbitrary position on the imaging surface. For example, by creating the signal sequence a (i) and the signal sequence b (i) described in the first embodiment from the first pixel 303a and the second pixel 303b arranged in the horizontal direction, the horizontal direction Ranging can be performed. Similarly, by generating the signal sequence a (i) and the signal sequence b (i) from the third pixel 303c and the fourth pixel 303d arranged in the vertical direction, distance measurement in the vertical direction can be performed. . The same applies to the oblique direction.

  A distance measuring operation by the second distance measuring unit 13b will be described. The second distance measuring unit 13b of the present embodiment can perform distance measurement using the TOF measurement method at an arbitrary position on the imaging surface. The second distance measuring unit 13b performs distance measurement using the TOF measurement method on the assumption that the reflected light beam 4 from the same position of the DUT 2 is incident on two adjacent pixels 303. Here, “two adjacent pixels 303” refers to two pixels 303 adjacent in the vertical direction, the horizontal direction, or the diagonal direction.

  The second distance measuring unit 13b reads a photoelectric conversion signal via the output unit 50 for one of the two adjacent pixels 303 at a predetermined time. The second distance measuring unit 13b then reads out the photoelectric conversion signal via the output unit 50 for the other of the two adjacent pixels 303. Assuming that the reflected light beam 4 from the same position of the DUT 2 is incident on these two pixels 303, the photoelectric conversion signal based on the reflected light beam 4 from the same position is divided in periods before and after a predetermined time as a boundary. However, they are read separately.

According to the imaging apparatus according to the second embodiment described above, the following functions and effects can be obtained in addition to the same functions and effects as those of the above-described first embodiment.
(11) The first distance measuring unit 13a and the second distance measuring unit 13b perform distance measurement at an arbitrary position on the imaging surface. Since it did in this way, the flexibility of a ranging position improves.

(12) The pixel 303 has a single output unit 50. Since it did in this way, the circuit structure of the imaging part 12 is simplified and manufacture of the imaging part 12 becomes easy.

  The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.

(Modification 1)
In the first embodiment, both the first distance measurement pixel 302a and the second distance measurement pixel 302b may be configured to include both the photodiode PDa and the photodiode PDb. In this case, the gate electrode 47 and the wiring 48 are provided in the lower layer of the layer where the photodiode PDa and the photodiode PDb are formed, with the imaging unit 12 having a two-layer structure. In this way, the light shielding member 42 is not necessary, and the utilization efficiency of incident light is improved. The third distance measuring pixel 302c and the fourth distance measuring pixel 302d can be similarly configured.

(Modification 2)
In each of the above-described embodiments, the distance measurement by the first distance measurement unit 13a and the distance measurement by the second distance measurement unit 13b are exclusively performed. However, these two types of distance measurement may be performed simultaneously. That is, the phase difference type distance measurement and the TOF measurement type distance measurement may be performed in parallel (or sequentially) on the photoelectric conversion signal based on the reflected light beam 4 to obtain both results. When the photoelectric conversion signal read from the first output unit 51 and the photoelectric conversion signal read from the second output unit 52 are added when performing the distance measurement using the TOF measurement method, the phase difference method can be used for distance measurement. Signal. In this case, the focus adjustment unit 13d may perform focus adjustment based on one of the distance measurement results, or may perform focus adjustment based on a distance obtained by averaging both distance measurement results.

(Modification 3)
In each of the above-described embodiments, the results of distance measurement by the first distance measuring unit 13a and the result of distance measurement by the second distance measuring unit 13b are used for focus adjustment. However, the results of distance measurement are used for different purposes. May be used. For example, a so-called depth map in which the distance of the device under test 2 is two-dimensionally mapped may be created, or may be used for creating a stereoscopic image of the device under test 2.

(Modification 4)
The receiving circuit 53 may be different from that shown in FIG. For example, the receiving circuit 54 illustrated in FIG. 12A clamps the feedthrough period immediately after the imaging pixel 30 is reset by the input capacitor 541 and the switch 542. After that, the photoelectric conversion signal is input to the amplifier 544 through the switch 543. The AD converter 546 converts the output signal of the amplifier 544 into a digital value. As another example, the receiving circuit 55 illustrated in FIG. 12B inputs a feedthrough period and a photoelectric conversion signal immediately after resetting the imaging pixel 30 to the amplifier 553 via the switch 551 and the switch 552, respectively. The AD converter 556 converts the output signal of the amplifier 553 into a digital value. Thereby, the reset signal and the photoelectric conversion signal are individually converted into digital values. The controller 13 removes the noise component by subtracting the former digital value from the latter digital value.

(Modification 5)
A circuit different from part of the first output unit 51 and the second output unit 52 may be disposed below the light shielding member 42. For example, some of the functions of the control unit 13 such as the first distance measuring unit 13a and the second distance measuring unit 13b may be built as an electronic circuit below the light shielding member 42.

(Modification 6)
The light blocking member 42 may be made of a material that absorbs light. In this case, the incident light is absorbed by the light blocking member 42, and as a result, does not reach the circuit below it.

(Modification 7)
In each of the above-described embodiments, the image sensor that photoelectrically converts incident light using a photodiode has been described. For example, an imaging element that performs photoelectric conversion using a photoelectric conversion film or the like formed of an organic material may be used.

  Note that the imaging apparatus according to the present embodiment is not limited to the imaging apparatus 1 as described above. For example, the present embodiment can be applied to a lens-integrated digital still camera, film still camera, or video camera. Furthermore, the present embodiment can also be applied to a small camera module built in an electronic device such as a mobile phone, a smart phone, and a tablet PC, a surveillance camera, a visual recognition device for a robot, an in-vehicle camera, and the like.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1 ... Imaging device, 10 ... Light source part, 11 ... Optical system, 12 ... Imaging part, 13 ... Control part, 13a ... 1st ranging part, 13b ... 2nd ranging part, 13c ... Photometric part, 13d ... Focus adjustment Part

Claims (16)

A first pixel that receives light from a subject that has passed through the first pupil region of the optical system and outputs a first signal; and a subject that has passed through a second pupil region different from the first pupil region. A second pixel that receives the light and outputs a second signal; and
The distance to the subject is measured based on a deviation between the subject image in the first pupil region received by the first pixel and the subject image in the second pupil region received by the second pixel. A first ranging unit to
A light source unit that emits light to irradiate the subject;
Based on the first signal output by the first pixel that receives light reflected by the subject out of the light, the time from light emission at the light source unit to light reception at the first pixel is detected. A second distance measuring unit for measuring the distance to
Electronic equipment comprising. The electronic device according to claim 1,
The imaging unit includes a first output unit that outputs the first signal based on light received by the first pixel between a first time and a second time, and between the second time and a third time. And a second output unit that outputs the first signal based on the light received by the first pixel,
The second distance measuring unit is a time from light emission to light reception at the light source unit based on the first signal output from the first output unit and the first signal output from the second output unit. Detecting electronic equipment. The electronic device according to claim 2,
The second distance measuring unit emits light from the light source unit based on a signal amount difference between the first signal output from the first output unit and the first signal output from the second output unit. An electronic device that detects the time from light to light reception. In the electronic device as described in any one of Claims 1-3,
A metering unit for metering the subject;
When the amount of light measured by the photometry unit is greater than or equal to a predetermined amount, the optical system is focused based on the measurement result of the first distance measurement unit, and the amount of light measured by the photometry unit is less than the predetermined amount In this case, an electronic apparatus further comprising: a focus adjusting unit that performs focus adjustment of the optical system based on a measurement result by the second distance measuring unit. In the electronic device as described in any one of Claims 1-3,
An electronic apparatus further comprising a control unit capable of selecting one of measurement by the first distance measurement unit and measurement by the second distance measurement unit. The electronic device according to claim 5,
A metering unit for metering the subject;
The said control part is an electronic device which performs one of the measurement by a said 1st ranging part and the measurement by a said 2nd ranging part based on the light quantity measured by the said photometry part. The electronic device according to claim 6,
The control unit performs measurement by the first distance measuring unit when the light amount measured by the photometry unit is equal to or greater than a predetermined amount, and when the light amount measured by the photometry unit is less than the predetermined amount. Electronic equipment that performs measurement by the second distance measuring unit. In the electronic device as described in any one of Claims 1-7,
The first pixel includes an electronic device including a microlens and a first photoelectric conversion unit, and the second pixel includes a microlens and a second photoelectric conversion unit. The electronic device according to claim 8,
The first pixel has a first light shielding portion that shields light that has passed through an area different from the first pupil area,
The electronic device, wherein the second pixel includes a second light shielding unit that shields light that has passed through an area different from the second pupil area. The electronic device according to claim 9,
An electronic apparatus in which at least a part of the first and second distance measuring units and the first and second output units are arranged in a range shielded by the first light shielding unit of the first pixel. In the electronic device as described in any one of Claims 1-7,
The first pixel includes an electronic device including a microlens, a first photoelectric conversion unit, and a third photoelectric conversion unit, and the second pixel includes a microlens, a second photoelectric conversion unit, and a fourth photoelectric conversion unit. The electronic device according to claim 11,
The first photoelectric conversion unit and the fourth photoelectric conversion unit receive light from a subject that has passed through the first pupil region of the optical system and output a first signal, respectively, and the second photoelectric conversion unit The third photoelectric conversion unit is an electronic device that receives light from a subject that has passed through the second pupil region of the optical system and outputs a second signal. In the electronic device as described in any one of Claims 1-12,
The imaging unit receives a light that has passed through a third pupil region that is different from the first pupil region and the second pupil region, and outputs a third signal, and the first to third pixels A fourth pixel that receives light that has passed through a fourth pupil region different from any of the pupil regions and outputs a fourth signal;
The direction in which the first pixel and the second pixel are arranged side by side is different from the direction in which the third pixel and the fourth pixel are arranged side by side. A first pixel that receives light from a subject that has passed through the first pupil region of the optical system and outputs a first signal; and a subject that has passed through a second pupil region different from the first pupil region. A second pixel that receives the light and outputs a second signal; and
From the imaging unit to the subject based on a deviation between the subject image in the first pupil region received by the first pixel and the subject image in the second pupil region received by the second pixel A first ranging unit for measuring the distance of
A light source unit that emits light to irradiate the subject;
Based on the signal output by the light receiving unit that receives the light reflected by the subject out of the light, the time from the light emission at the light source unit to the light reception at the light receiving unit is detected and the distance to the subject is measured. A second ranging unit;
An electronic apparatus comprising: a control unit capable of selecting one of measurement by the first distance measurement unit and measurement by the second distance measurement unit. The electronic device according to claim 14,
A metering unit for metering the subject;
The said control part is an electronic device which performs one of the measurement by a said 1st ranging part and the measurement by a said 2nd ranging part based on the light quantity measured by the said photometry part. The electronic device according to claim 15,
The control unit performs measurement by the first distance measuring unit when the light amount measured by the photometry unit is equal to or greater than a predetermined amount, and when the light amount measured by the photometry unit is less than the predetermined amount. Electronic equipment that performs measurement by the second distance measuring unit.

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