JP2015099208A - Camera unit and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further shorten the time required for searching for a best focus position.SOLUTION: A camera unit comprises: a center position focusing part (5) setting a focus position of an optical element part (3) to each of the inside of an infinity side area and the inside of a macro side area; and a focus evaluation value comparison part (6) comparing a focus evaluation value when a focus position of the optical element part (3) is set in the infinity side area with a focus evaluation value when the focus position of the optical element part (3) is set in the macro side area. A focusable range is updated to one of the infinity side area and the macro side area that corresponds to the larger value of the focus evaluation values.

Description

  The present invention relates to a camera unit and an electronic device mounted on a mobile phone or the like. In particular, the present invention includes an image sensor and a focus adjustment optical element, and performs a focus adjustment by the focus adjustment optical element so that a focus evaluation value calculated from an output signal of the image sensor is maximized. And an electronic device including the camera unit.

  In recent years, camera units equipped with camera modules have been incorporated into a wide variety of products. When a camera unit is mounted on a small electronic device such as a mobile phone or a laptop computer, there is a strong demand for downsizing and power saving of the camera unit itself.

  The camera unit may incorporate a focus adjustment function that changes the focal length and the focal position of the optical system.

  Conventionally, as a focus adjustment function, a method of moving a lens unit that focuses light on an image sensor has been widely used. As a method for moving the lens unit, there are a voice coil motor method for moving the lens unit up and down by magnetic force, a method for moving the lens unit by driving a piezoelectric element that is a piezoelectric element, and the like.

  In the method of moving the lens unit, a mechanism for driving the lens unit is required, and the structure of this mechanism is complicated. In this method, it is necessary to move the lens unit for focus adjustment. For this reason, this method has the disadvantages that it takes time to adjust the focus and that the power consumption is relatively large. In addition, the camera unit that performs focus adjustment by the same method has a drawback that the impact resistance is generally lowered.

  In the case of the method of moving the lens unit, the principle of extracting a high-frequency component corresponding to the contrast of the captured image from the output signal of the image sensor and moving the lens unit to the lens position where the high-frequency component is maximum is known. Yes. This principle is called hill-climbing AF (Auto Focus). In particular, this high frequency component is generally called a focus evaluation value.

  Specifically, in hill-climbing AF, the lens unit is gradually moved over the entire drive area, and focus evaluation values are acquired for the respective lens positions. In other words, the lens unit is moved from the position closest to the subject (infinite position) to the position closest to the image sensor (macro position). Then, a maximum one is selected from the acquired focus evaluation values, and the lens unit is moved to a lens position where the maximum focus evaluation value is obtained.

  In hill-climbing AF, it is necessary to acquire focus evaluation values at regular intervals over the entire movable range of the lens unit. For this reason, in order to improve the search accuracy of the best focus position, it is necessary to make the constant interval smaller. If the fixed interval is reduced, the total acquisition time of the focus evaluation value becomes long, and there is a disadvantage that it takes a long time to search for the best focus position.

  By the way, in recent years, attention has been paid to a method of driving a focus adjustment optical element provided on or in the lens unit as a focus adjustment function of the camera unit.

  Patent Document 1 discloses a liquid crystal optical element capable of adjusting a focal position by changing a refractive index. The liquid crystal optical element functions as a variable focus lens by changing the refractive index distribution in the liquid crystal optical element by changing the drive voltage applied to the liquid crystal optical element.

  Patent Document 2 discloses a specific configuration of a liquid lens.

  Patent Document 3 includes a first layer and a polymer layer, and changes the shape of the first layer and the polymer layer by applying a voltage to a piezoelectric element arranged in the first layer, A variable focus lens that adjusts a focal position by changing a refractive index by changing a shape is disclosed.

  The lenses disclosed in Patent Documents 1 to 3 are generally arranged on the upper surface of a lens barrel of a fixed focus camera unit. By applying a voltage to the lens and changing the refractive index of the lens, the focal position of the camera unit can be adjusted. Thereby, the camera unit can have a variable focus function.

  By using the lenses disclosed in Patent Documents 1 to 3 as focus adjustment optical elements, it is possible to shorten the time required for searching for the best focus position. This is because it is not necessary to physically move the focus adjustment optical element, and therefore, it is not necessary to move the optical element (lens).

JP 2006-145957 A (released on June 8, 2006) Special table 2009-525501 gazette (announced July 9, 2009) Japanese Patent No. 5244806 (issued July 24, 2013)

  However, Patent Documents 1 to 3 do not mention the principle of searching for the refractive index of the focus adjustment optical element that maximizes the focus evaluation value. There is room for further shortening the time required for searching for the best focus position by reducing the time for searching for the refractive index of the focus adjustment optical element that maximizes the focus evaluation value.

  The present invention has been made in view of the above problems, and an object thereof is to provide a camera unit and an electronic apparatus that can further reduce the time required for searching for the best focal position. .

  In order to solve the above problems, a camera unit according to one aspect of the present invention includes a lens unit including one or more lenses and a focus adjustment optical element whose focus position is adjustable. The camera unit includes an optical element unit that condenses incident light, and an image sensor that receives light collected by the optical element unit and outputs a signal corresponding to the received light. A focusing unit that sets a focal position of the optical element unit so that a focus evaluation value that is a high-frequency component corresponding to the contrast of the captured image obtained from the output signal of the imaging element is maximized, and the focusing unit. The focusable range that can be set as the focal position of the optical element unit by the focusing unit is divided into an infinite region that is the subject side region and a macro side region that is the focus adjustment optical element side region. In the infinity region and the A specific position focusing unit for setting the focal position of the optical element unit in each of the black side regions, and the specific position focusing unit when the focal position of the optical element unit is set in the infinity side region A focus evaluation value comparing unit that compares the focus evaluation value with the focus evaluation value when the specific position focusing unit sets the focal position of the optical element unit in the macro side region; The focusable range is updated to one of the infinity side region and the macro side region corresponding to the larger one of the focus evaluation values compared by the focus evaluation value comparison unit. It is characterized by.

  According to one aspect of the present invention, it is possible to further reduce the time required for searching for the best focus position.

It is a block diagram which shows schematic structure of the camera unit which concerns on embodiment of this invention. It is an overhead view of the camera unit. It is a graph which shows an example of the relationship between the focus position of an optical element part, and a focus evaluation value. It is a graph which shows an example of the division | segmentation into a primary infinity side area | region and a primary macro side area | region. It is a graph which shows an example of the division | segmentation into a secondary infinity side area | region and a secondary macro side area | region. It is a graph which shows an example of the division | segmentation into a tertiary infinity side area | region and a tertiary macro side area | region. It is a graph which compares the performance of the focus search method which concerns on embodiment of this invention, and the focus search method which concerns on a prior art.

[Summary of the Invention]
A camera unit according to the present invention includes one or a plurality of lenses for forming an image of a subject on an image sensor, and a focus adjusting optical element for adjusting a focal position on the optical axis of the optical element section. . The focus adjustment optical element is arranged on the upper part of the lens or inside at least one lens. A camera unit including a focus adjustment optical element can change the focus position of the optical element unit by changing the refractive index of the focus adjustment optical element without moving the position of each lens. . Therefore, the best focus position as a camera unit can be searched at a sufficiently high speed as compared with the conventional voice coil motor system and the system using the piezoelectric element. Using this advantage, a new technique (two-point focus evaluation value comparison method) is proposed in place of the conventional hill-climbing AF when the focus position of the optical element unit is set using the focus evaluation value. This technique makes it possible to further reduce the time required for searching for the best focus position.

  In hill-climbing AF, when searching for the best focus position, each lens (lens unit) is moved from the position closest to the subject (infinity position) to the position closest to the image sensor (macro position), and is constant within the movement range. A focus evaluation value is acquired at every interval. On the other hand, when the focus adjustment optical element is used, the focus position of the optical element section can be moved at a high speed, so that the search for the best focus position faster than the hill-climbing AF can be realized.

  The focusable range indicating the range of positions that can be set as the focus position of the optical element section is divided into the subject side and the focus adjustment optical element side (imaging element side), and focus evaluation values at specific positions on each side To get. Then, the focus evaluation values acquired at the specific positions on each side are compared, and the focusable range is updated so that only the side corresponding to the larger focus evaluation value is set as a new focusable range. Further, the focusable range is updated in the same manner as described above with respect to the focusable range after the update. By repeatedly updating the focusable range and sufficiently narrowing the range of positions that can be set as the focal position of the optical element unit, the search time can be greatly reduced by performing a search.

Embodiment
FIG. 1 is a block diagram showing a schematic configuration of a camera unit 1 according to the present embodiment.

  FIG. 2 is an overhead view of the camera unit 1.

  The camera unit 1 is an AF camera unit having a function of imaging the subject 2.

  As shown in FIG. 1, the camera unit 1 includes a camera module 10, an analog front end 14, a camera signal processing unit 15, a recording medium 16, a display unit 17, an AF evaluation value calculation circuit 18, a system controller 19, and an AF unit control driver. (Focusing part) 20 is provided.

  The camera module 10 also includes a focus adjustment AF unit (focus adjustment optical element) 11, a lens unit (lens unit) 12, and a solid-state image pickup element (image pickup element) 13. The focus adjustment AF unit 11 and the lens unit 12 constitute an optical element unit 3 of the camera unit 1.

  Further, the system controller 19 includes an in-focus position specifying unit (in-focus unit) 4, a center position in-focus unit (specific position in-focus unit) 5, and a focus evaluation value comparison unit 6.

  The analog front end 14 includes a CDS (correlated double sampling) circuit, an AGC (automatic gain control) circuit, and an ADC (analog-digital conversion) circuit.

  As shown in FIG. 2, the camera unit 1 has a structure including a focus adjustment AF unit 11, a holder 22, a substrate 23, and an electrode 24.

  In the camera unit 1, the lens unit 12 is disposed inside the holder 22 and includes a plurality of lenses. The lens unit 12 (each lens constituting the lens unit 12) is relatively fixed to the camera unit 1. Note that one lens may be used instead of the lens unit 12 including a plurality of lenses.

  The solid-state image sensor 13 is disposed on the upper surface of the substrate 23.

  The focus adjustment AF unit 11 is electrically connected to the substrate 23 by the electrode 24, and a voltage is supplied from the electrode 24. By controlling the voltage supplied from the electrode 24 to the focus adjustment AF unit 11, it is possible to adjust the refractive index of the focus adjustment AF unit 11 and control the focus position of the focus adjustment AF unit 11. . That is, the focus adjustment AF unit 11 is relatively fixed to the camera unit 1, but the focus position can be adjusted.

  Hereinafter, the generic name of the focus adjustment AF unit 11 and the lens unit 12 is referred to as an optical element unit 3.

  Light from the subject 2 enters the optical element unit 3. The optical element unit 3 collects the incident light.

  The solid-state imaging device 13 receives the light collected by the optical element unit 3 and outputs a signal corresponding to the received light. The solid-state imaging device 13 is an integrated circuit photoelectric conversion device, and mainly includes a CMOS (Complementary Metal Oxide Semiconductor) type, a CCD (Charge Coupled Device) type, and the like. . An image of the subject 2 is formed on the solid-state image sensor 13, and signal charges are accumulated for each pixel of the solid-state image sensor 13 in accordance with the intensity of the light of the formed image.

  The signal charges accumulated in each pixel of the solid-state imaging device 13 are input to the analog front end 14 as a video output signal. The analog front end 14 converts the input signal from an analog signal to a digital signal and outputs the converted signal.

  The digital signal output from the analog front end 14 is input to the camera signal processing unit 15. The camera signal processing unit 15 performs various types of signal processing on the input signal, and converts this signal into image data in a predesignated format. The image data is stored in the recording medium 16. Further, the camera unit 1 can display an image of the subject 2 on the display unit 17 as an image based on the image data.

  The digital signal output from the analog front end 14 is input to the AF evaluation value calculation circuit 18. The AF evaluation value calculation circuit 18 extracts a high frequency component corresponding to the contrast of the captured image of the camera unit 1 from the input digital signal. The extracted high-frequency component is a focus evaluation value, and serves as an index of whether the focus position of the optical element unit 3 with respect to the subject 2 is good or bad. That is, it can be said that the larger the focus evaluation value, the higher the accuracy of the focus of the optical element unit 3 with respect to the subject 2 and the more suitable the focus position of the optical element unit 3. It can be said that the focus evaluation value is obtained from the output signal of the solid-state image sensor 13.

  The focus evaluation value obtained by the AF evaluation value calculation circuit 18 is taken into the system controller 19. From here, the operation of the system controller 19 will be described.

  The in-focus position specifying unit 4 adjusts the focus position of the focus adjustment AF unit 11 and sets the focus position of the optical element unit 3 so that the focus evaluation value is maximized. The in-focus position specifying unit 4 selects the maximum one from a plurality of focus evaluation values obtained from the AF evaluation value calculation circuit 18 (that is, obtained from a plurality of points at the focal position of the optical element unit 3), The focus position of the optical element unit 3 corresponding to the selected focus evaluation value is specified. Then, the focus position specifying unit 4 supplies a signal indicating the specified focus position to the AF unit control driver 20.

  The AF unit control driver 20 converts the signal indicating the specified focus position supplied from the focus position specifying unit 4 into a voltage and supplies the voltage to the focus adjustment AF unit 11. In the focus adjustment AF unit 11, the refractive index changes according to the voltage value supplied from the AF unit control driver 20, and the focus position changes.

  The center position focusing unit 5 divides a focusable range indicating a range of positions that can be set as a focal position of the optical element unit 3 into an infinitely far side region and a macro side region. Here, the infinity-side region is a region within the focusable range and from the position closest to the subject 2 to a predetermined position. On the other hand, the macro side region is a region within the focusable range and from the predetermined position to the position closest to the focus adjustment AF unit 11 side (that is, the solid-state imaging device 13 side). Here, an example of the predetermined position includes an intermediate position between the position closest to the subject 2 and the position closest to the focus adjustment AF unit 11, but is not limited thereto.

  Further, the center position focusing unit 5 sets the focal position of the optical element unit 3 at each of the center position (specific position) of the infinity side region and the center position (specific position) of the macro side region. That is, the center position focusing section 5 has a signal indicating that the focal position of the optical element section 3 is the center position of the infinity side area and the focal position of the optical element section 3 is the center position of the macro side area. Are sequentially supplied to the AF unit control driver 20. At this time, the AF unit control driver 20 converts each signal supplied from the center position focusing unit 5 into a voltage and supplies it to the focus adjustment AF unit 11.

  The focus evaluation value comparison unit 6 includes a focus evaluation value when the center position focusing unit 5 sets the focus position of the optical element unit 3 to the center position of the infinity side region, and the center position focusing unit 5 includes the optical element unit. The focus evaluation value when the focus position of 3 is set to the center position of the macro side region is compared. In other words, the focus evaluation value comparison unit 6 determines the focus evaluation value when the focus position of the optical element unit 3 is the center position of the infinity side region and the focus position of the optical element unit 3 is the center position of the macro side region. Is compared with the focus evaluation value. If each of these focus evaluation values is acquired from the AF evaluation value calculation circuit 18, the comparison by the focus evaluation value comparison unit 6 is easy.

  Further, the in-focus position specifying unit 4 further updates only one of the infinity side region and the macro side region corresponding to the larger one of the focus evaluation values compared by the focus evaluation value comparison unit 6. The focusable range is updated so that the focusable range.

  That is, as a result of the comparison by the focus evaluation value comparison unit 6, if the focus evaluation value when the focus position of the optical element unit 3 is set to the center position of the infinity side region is larger, the focusable range is the infinity side. The area and macro side area are updated only to the infinity side area. That is, at this time, the in-focus position specifying unit 4 specifies the above-described focal position of the optical element unit 3 in the infinity side region, but does not specify this in the macro side region.

  On the contrary, if the focus evaluation value when the focus position of the optical element unit 3 is set to the center position of the macro side region is larger as a result of the comparison by the focus evaluation value comparison unit 6, the focusable range is the infinity side. The area and macro side area are updated only to the macro side area. That is, at this time, the focus position specifying unit 4 specifies the above-described focal position of the optical element unit 3 in the macro side region, but does not specify this in the infinity side region.

[Details of updating the focusable range]
FIG. 3 is a graph showing an example of the relationship between the focus position of the optical element unit 3 and the focus evaluation value.

  In the graph shown in FIG. 3, the horizontal axis indicates the focal position of the optical element unit 3, and the vertical axis indicates the focus evaluation value. In the drawing, inf indicates the infinity side, and the infinity side corresponds to the subject 2 side. In the drawing, macro indicates the macro side, and the macro side corresponds to the focus adjustment AF unit 11 side.

  “Area 0” in FIG. 3 is an initial in-focusable range in the optical element unit 3, that is, an in-focusable range to which no restriction is given by updating the in-focusable range. “Area 0” is, for example, equal to the range of all focal positions that can be taken by the optical element unit 3 provided in the camera unit 1.

  In the graph shown in FIG. 3, P1 to P15 indicate sampling points in “area 0”. Note that the sampling points P1 to P15 are preferably set at regular intervals in “area 0”. On the other hand, in the graph shown in FIG. 3, F1 to F15 indicate focus evaluation values at sampling points P1 to P15, respectively.

  In the example shown in FIG. 3, the focus evaluation value F9 at the sampling point P9 is the maximum. That is, the best focal position (focus position) of the optical element unit 3 at this time is the sampling point P9, and the actual focal position of the optical element unit 3 is set at the sampling point P9.

  FIG. 4 is a graph showing an example of the division into the primary infinity side region and the primary macro side region.

  In the present specification, “n-order (where n is a natural number)” means that the center position focusing unit 5 and the focus evaluation value comparison unit 6 perform the above-described series of operations (the above-described operations) n times. Is shown.

  First, the center position focusing unit 5 divides the initial focusable range “area 0” into a primary infinity side area “area 1” and a primary macro side area “area 2”. Then, the focal position of the optical element unit 3 is set to the sampling point P4 corresponding to the center position of “area 1” and the sampling point P12 corresponding to the center position of “area 2” by the center position focusing unit 5. To do.

  The focus evaluation value comparison unit 6 compares the focus evaluation value F4 at the sampling point P4 with the focus evaluation value F12 at the sampling point P12. As is clear from the graph shown in FIG. 4, the focus evaluation value F12 is larger than the focus evaluation value F4.

  In response to the comparison result by the focus evaluation value comparison unit 6, the focus position specifying unit 4 replaces only the area including the sampling point P12 from which the focus evaluation value F12 is obtained, that is, “area 2” with “area 0”. The focusable range is set. This can be interpreted as the focus position specifying unit 4 updating the focusable range so that only “area 2” corresponding to the focus evaluation value F12 is set as a new focusable range. it can.

  “Area 2” is a primary focusable range, that is, a focusable range after the focusable range is updated once.

  FIG. 5 is a graph showing an example of the division into the secondary infinity side region and the secondary macro side region.

  The center position focusing unit 5 divides the primary focusable range “area 2” into a secondary infinity side area “area 3” and a secondary macro side area “area 4”. Then, the focal position of the optical element unit 3 is set to the sampling point P10 corresponding to the center position of “area 3” and the sampling point P14 corresponding to the center position of “area 4” by the center position focusing unit 5. To do.

  The focus evaluation value comparison unit 6 compares the focus evaluation value F10 at the sampling point P10 with the focus evaluation value F14 at the sampling point P14. As is clear from the graph shown in FIG. 5, the focus evaluation value F10 is larger than the focus evaluation value F14.

  In response to the comparison result by the focus evaluation value comparison unit 6, the focus position specifying unit 4 replaces only the area including the sampling point P10 from which the focus evaluation value F10 is obtained, that is, “area 3” with “area 2”. The focusable range is set. This can be interpreted as the focus position specifying unit 4 updating the focusable range so that only “area 3” corresponding to the focus evaluation value F10 is set as a new focusable range. it can.

  “Area 3” is a secondary focusable range, that is, a focusable range after the focusable range is updated twice.

  FIG. 6 is a graph showing an example of division into the third-order infinity side region and the third-order macro side region.

  The center position focusing unit 5 divides the secondary focusable range “area 3” into a tertiary infinity side area “area 5” and a tertiary macro side area “area 6”. Then, the focal position of the optical element unit 3 is set to the sampling point P9 corresponding to the center position of “area 5” and the sampling point P11 corresponding to the center position of “area 6” by the center position focusing unit 5. To do.

  The focus evaluation value comparison unit 6 compares the focus evaluation value F9 at the sampling point P9 with the focus evaluation value F11 at the sampling point P11. As is clear from the graph shown in FIG. 6, the focus evaluation value F9 is larger than the focus evaluation value F11.

  In response to the comparison result by the focus evaluation value comparison unit 6, the focus position specifying unit 4 replaces only the area including the sampling point P9 from which the focus evaluation value F9 is obtained, that is, “area 5” with “area 3”. The focusable range is set. This can be interpreted as the focus position specifying unit 4 updating the focusable range so that only “area 5” corresponding to the focus evaluation value F9 is set as a new focusable range. it can.

  “Area 5” is a tertiary focusable range, that is, a focusable range after the focusable range is updated three times. “Area 5” is a significantly narrower area than “Area 0”. In addition, “area 5” includes a sampling point P9 at which the maximum focus evaluation value F9 among the focus evaluation values F1 to F15 is obtained. By searching for the best focus position (in-focus position) of the optical element unit 3 using only “Area 5”, the search time can be significantly reduced compared to the case where the same search is performed for “Area 0” as a whole. .

  As described with reference to FIGS. 3 to 6, the center position focusing unit 5 and the focus evaluation value comparison unit 6 perform each operation (setting of the focus position of the optical element unit by the specific position focusing unit and focus evaluation). Comparison of the focus evaluation values by the value comparison unit) is performed a plurality of times, and the in-focus position specifying unit 4 causes a new in-focusable range each time the center position in-focus unit 5 and the focus evaluation value comparison unit 6 operate once. Is preferably set.

  In particular, if “area 5” is set so that only sampling point P9 is included among sampling points P1 to P15, the best focal position (focusing position) of optical element unit 3 is no longer sampling point P9. Becomes clear. In this case, the number of focus evaluation values acquired is a total of six focus evaluation values F4, F9, F10, F11, F12, and F14, which is 40% of the case where all the focus evaluation values F1 to F15 are acquired with the same resolution. It becomes.

Assume that the focusable range is L, the resolution at the time of search is r, and the number of acquired focus evaluation values is m. In the method of acquiring focus evaluation values at all sampling points,
m = L / r
It becomes.

On the other hand, in the method shown in FIGS.
r = L / 2 ^m
m = log ₂ (L / r)
It becomes.

As an example, let us consider a case where the focusable range L is 3 meters and the resolution r at the time of search is 0.05 meters. In the method of acquiring focus evaluation values at all sampling points,
m = 3 / 0.05 = 60
Thus, the number of acquired focus evaluation values is 60.

On the other hand, in the method shown in FIGS.
m = log ₂ (3 / 0.05) = 5.90
Thus, the number of acquired focus evaluation values is 6 at a minimum. The number of acquired focus evaluation values in the methods shown in FIGS. 3 to 6 is 10% of the acquired number of focus evaluation values in the method of acquiring focus evaluation values at all sampling points.

  FIG. 7 is a graph comparing the performance of the focus search method according to the embodiment and the focus search method according to the prior art. The former is the focus searching method of the camera unit 1, that is, the method shown in FIGS. The latter is a conventional camera unit focus search method, that is, a method of acquiring focus evaluation values at all sampling points.

  FIG. 7 shows the result when the focusable range is 3 meters. In the graph shown in FIG. 7, the horizontal axis indicates the resolution at the time of search, and the vertical axis indicates the number of acquisitions of the minimum focus evaluation value.

  In the conventional camera unit focus search method, when the search resolution decreases, the number of acquired focus evaluation values increases so as to be inversely proportional to the search resolution. When the resolution at the time of search is 0.1 meter, the number of acquisition of the focus evaluation value is 30, and when the resolution at the time of search is 0.01 meter, the number of acquisition of the focus evaluation value is 300.

  On the other hand, in the focus search method of the camera unit 1, when the resolution at the time of search is 0.1 meter, the number of acquisition of focus evaluation values is 12, and when the resolution at the time of search is 0.01 meters, the focus evaluation value The number of acquisitions is 15. When the resolution at the time of search is 0.01 meter, the number of acquired focus evaluation values in the focus search method of the camera unit 1 can be reduced to 5% of the focus search method of the conventional camera unit. The focus searching method of the camera unit 1 has a greater effect of reducing the number of acquired focus evaluation values as the resolution at the time of searching is smaller.

  Since the camera unit 1 has a high focus position search speed, it can be said that the camera unit 1 has a high-speed AF function.

[Additional Notes]
The predetermined position related to the camera unit 1, that is, the position where the focusable range is divided into the infinity side region and the macro side region is an intermediate position between the position closest to the subject 2 and the position closest to the focus adjustment AF unit 11. It is not limited to. That is, the predetermined position is within a focusable range, and any position is provided as long as both the infinity side region and the macro side region have at least one of the sampling points P1 to P15. Also good.

  In the above-described embodiment, an example is shown in which the focus evaluation value is acquired at the center position of the infinity side region. However, the focus evaluation value may be acquired at a position outside the center position in the infinity side region. . Similarly, in the above-described embodiment, an example in which the focus evaluation value is acquired at the center position of the macro side region has been described, but the focus evaluation value may be acquired at a position outside the center position in the macro side region. Good. This indicates that the focal position of the optical element unit 3 set by the center position focusing unit 5 need only be one arbitrary position in the infinity side region and one arbitrary point in the macro side region. ing. However, in order to make the condition for acquiring the focus evaluation value in the infinity side region and the condition for acquiring the focus evaluation value in the macro side region as similar as possible, It is preferable to acquire the focus evaluation value at the center position.

  The focus adjustment AF unit 11 of the camera unit 1 may be disposed on the upper part of the lens unit 12 or may be disposed inside one of the lenses constituting the lens unit 12.

  An electronic device including the camera unit 1 is also included in the scope of the present invention. Examples of the electronic device include a digital camera, a mobile phone, a smartphone, a notebook PC, a tablet terminal, an electronic book reader, a PDA (Personal Digital Assistants), or a television.

[Summary]
A camera unit according to aspect 1 of the present invention includes a lens unit (lens unit 12) including one or a plurality of lenses, a focus adjustment optical element (focus adjustment AF unit 11) whose focus position is adjustable, and the like. And an image sensor (solid-state image sensor 13) that receives the light collected by the optical element unit and outputs a signal corresponding to the received light. ), And the focus position of the optical element unit so that the focus evaluation value, which is a high-frequency component corresponding to the contrast of the captured image obtained from the output signal of the image sensor, is maximized. The focus area (focus position specifying section 4 and AF unit control driver 20) for setting the focus range that can be set as the focal position of the optical element section by the focus section is the area on the subject side Nothing A specification for dividing the far-side region and the macro-side region that is the region on the optical element for focus adjustment, and setting the focal position of the optical element unit in each of the infinity-side region and the macro-side region The focus evaluation value when the position focus section (center position focus section 5) and the specific position focus section set the focus position of the optical element section in the infinity side region, and the specific position focus A focus evaluation value comparing unit that compares the focus evaluation value when the focus unit sets the focus position of the optical element unit in the macro side region, and the focusable range is the focus evaluation value The focus evaluation value compared by the value comparison unit is updated to one of the infinity side region and the macro side region corresponding to the larger one.

  According to said structure, after narrowing the range of the position which can be set as a focus position of an optical element part, search time can be shortened by performing a search.

  The camera unit according to Aspect 2 of the present invention is the camera unit according to Aspect 1, wherein the focusable range is the setting of the focal position of the optical element unit by the specific position focusing unit and the focus evaluation value comparing unit. Updated every time the focus evaluation value is compared.

  According to the above configuration, the search time can be significantly shortened by performing a search after sufficiently narrowing the range of positions that can be set as the focal position of the optical element unit by repeatedly updating the focusable range. Can do.

  In the camera unit according to aspect 3 of the present invention, in the aspect 1 or 2, the optical element for focus adjustment is disposed above the lens unit.

  In the camera unit according to aspect 4 of the present invention, in the aspect 1 or 2, the focus adjustment optical element is disposed inside the one lens or any one of the plurality of lenses. .

  The camera unit according to Aspect 5 of the present invention is the camera unit according to any one of Aspects 1 to 4, wherein the focusing unit controls a voltage supplied to the focus adjustment optical element, thereby controlling the focus adjustment optical element. Adjust the focus position.

  An electronic apparatus according to an aspect 6 of the present invention includes the camera unit according to any one of the above aspects 1 to 5.

  According to said structure, there exists an effect similar to the camera unit in any one of the said aspects 1-5.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  The present invention can be used for a camera unit and an electronic device mounted on a mobile phone or the like. In particular, the present invention includes an image sensor and a focus adjustment optical element, and performs a focus adjustment by the focus adjustment optical element so that a focus evaluation value calculated from an output signal of the image sensor is maximized. And an electronic device equipped with this camera unit.

DESCRIPTION OF SYMBOLS 1 Camera unit 2 Subject 3 Optical element part 4 Focus position specific | specification part (focusing part)
5 Center position focusing part (specific position focusing part)
6 Focus Evaluation Value Comparison Unit 10 Camera Module 11 Focus Adjustment AF Unit (Focus Adjustment Optical Element)
12 Lens unit (lens part)
13 Solid-state imaging device (imaging device)
14 Analog Front End 15 Camera Signal Processing Unit 16 Recording Medium 17 Display Unit 18 AF Evaluation Value Calculation Circuit 19 System Controller 20 AF Unit Control Driver (Focus Unit)
F1 to F15 Focus evaluation values P1 to P15 Sampling points

Claims (5)

An optical element unit that includes a lens unit including one or a plurality of lenses, and a focus adjustment optical element whose focus position is adjustable, and condenses incident light;
A camera unit including an image sensor that receives light collected by the optical element unit and outputs a signal corresponding to the received light;
A focusing unit that sets a focal position of the optical element unit so that a focus evaluation value that is a high-frequency component corresponding to a contrast of a captured image obtained from an output signal of the imaging element is maximized;
The focusable range that can be set as the focal position of the optical element unit by the focusing unit is divided into an infinity side region that is a subject side region and a macro side region that is a region on the focus adjustment optical element side. A specific position focusing unit that divides and sets the focal position of the optical element unit in each of the infinity side region and the macro side region;
The focus evaluation value when the specific position focusing unit sets the focal position of the optical element unit in the infinity side region, and the specific position focusing unit sets the focal position of the optical element unit to the macro side. A focus evaluation value comparison unit that compares the focus evaluation value when set in the region,
The focusable range is updated to one of the infinity side region and the macro side region corresponding to the larger one of the focus evaluation values compared by the focus evaluation value comparison unit. A camera unit characterized by   The focusable range is updated each time the focus position of the optical element unit is set by the specific position focusing unit and the focus evaluation value is compared by the focus evaluation value comparison unit. The camera unit according to claim 1.   The camera unit according to claim 1, wherein the focus adjustment optical element is disposed on an upper portion of the lens unit.   3. The camera unit according to claim 1, wherein the focus adjustment optical element is arranged inside the one lens or any one of the plurality of lenses. 4.   An electronic apparatus comprising the camera unit according to claim 1.

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