201109809 六、發明說明： 【發明所屬之技術領域】 本發明涉及實際地使透鏡移動來確定焦點位置的聚 焦控制電路。 【先前技術】 在一般的數位相機和移動電話中搭載的攝像頭模組 大多具備自動聚焦功能。這種小型攝像頭所具備的自動聚 焦功能大多採用對比度檢測方式。對比度檢測方式是下述 方式，即，實際地使透鏡移動，檢測出拍攝圖像内的被攝 體的對比度被最大化的透鏡位置，使透鏡移動到該位置的 方式（例如參照專利文獻1)。 [專利文獻1]日本特開2006— 166403號公報 對比度檢測方式與向被攝體照射紅外線或超聲波並 根據其反射波測定到被攝體的距離的有源方式相比，能夠 以低成本實現。不過，存在搜索到被攝體的對比度被最大 化的透鏡位置為止耗費時間的問題。在數位相機中，希望 在使用者半按快門按鈕後至對焦到被攝體為止的處理在一 秒内完成。 但是，在一般的數位相機和移動電話中搭載的攝像頭 模組的像素數逐年增加，這些小型攝像頭也逐漸能夠拍攝 高清晰的圖像。在高清晰圖像中，焦點偏差容易察覺，而 要求更高精度的自動聚焦控制。 【發明内容】 本發明鑒於上述情況而實現，目的在於提供一種在實 4 322170 201109809 際地使透鏡移動來確定焦點位置的自動聚焦控制中，能多句 在不降低對焦精度的情況下縮短處理時間的技術.。 ，本發明的一個方式的聚焦控制電路，搭載於具備透 鏡、用於調節該透鏡的位置的驅動元件和用於檢測該透鏡 的位置的位置檢測元件的攝像裝置中，該聚焦控制電路具 備：均衡器，其基於根據位置檢測元件的輸出信號確定的 透鏡的位置與設定的位置之間的差分，生成用於使透鏡的 位置對位到設定的位置的驅動信號，對驅動元件進行控 制；和位置設定部’其在從外部收到透鏡的目標位置的變 更指示時，將從原目標位置到達新目標位置為止這一範圍 的多個位置依次設定到均衡器中。 本發明的另一方式是攝像裝置。該裝置具備：透鏡； 將透過透鏡後的光變換為電信號的攝像元件；用於調節透 鏡的位置的驅動元件；用於檢測透鏡的位置的位置檢測元 件；和上述聚焦控制電路。 (發明效果） 根據本發明’在實際地使透鏡移動來確定焦點位董的 自動聚焦控制中’能夠在不降低對焦精度的情況下縮短處 理時間。 【實施方式】 第1圖是表示搭載了實施方式中的聚焦控制電路100 的攝像裝置500的結構圖。攝像裝置500包括：透鏡10、 驅動元件12、位置檢測元件14、攝像元件16、圖像信號 處理部（ISP: Image Signal Processor)50 和聚焦控制電 5 322170 201109809 路100。這裏，省略了圖像編碼引擎和 聚焦控制無關的結構要素。 、、媒J專與自動 攝像元件16將透過作為光學部件的透 號變換成電信號，並輸出到圖像信號處、’ ，、、 元件16可採用⑽感測器或⑽_像感卿。。對於攝像 驅動70件12是調節透鏡10的位置的元件 焦控制電路100提供的驅動信號在光軸方向上 <爆從聚 10。由此，透鏡1〇與攝像元件16的焦距被調Ϊ移:2 動元件12玎採用音圈馬達（VCM)。 、° 位置檢測元件14是用於檢測透鏡1〇的位置的元4 對於位置檢測元件14可採用霍爾元件。以下，對。 12和位置檢測元件14由包括音圈馬達和霍爾元 器構成的例子進行說明。 勡 圖像信號處理部對從攝像元件16輸出的圖像信號 進行處理。在本實施方式中，主要基於從攝像元件16輸出 的圖像信號來球定透鏡的對焦位置。 ' 第2圖是用於說明圖像信號處理部50進行的透鏡1〇 的對焦位置的確定處理的圖。在快門按鈕被半按等自^聚 焦功能有效時，圖像信號處理部50向聚焦控制電路1〇〇 發送用於使透鏡10以規定步幅移動的控制信號。此時，圖 像信號處理部50計算在透鏡10的各目標位置處拍攝得到 的各圖像信號的清晰度（sharPness)。例如，可透過對各圖 像信號進行高通濾波提取各圖像信號的邊緣成分，並對各 圖像信號的邊緣成分進行累積來求取清晰度。圖像信號處 322170 6 201109809 理部50將清晰度為最大值的透* 1〇的位置確定為對焦位 置。 “、' 第2圖中表不了透過兩個階段的掃描來確定對隹位置 的例子。在第一階段的掃.推中，粗略變更魏1〇的位置， 從而將透鏡1G的對焦位置鎖定到某—程度的範圍内。更具 體而言，將持續增加的清晰度轉為減少時的目標位置Μ -個目標位置之間的範圍指定為透鏡1〇的對焦位置所在 的範圍。在第二階段的掃插中，在透過第一階段的掃插而 鎖定的範圍内細微變更透鏡10的位置，將清晰度為最大值 的透鏡10的位置確定為對焦位置。透過這兩個階段的掃 描’能夠南速且尚精度地搜索到對焦位置。 回到第1圖，聚焦控制電路100包括：差動放大電路 20、低通濾波器22、類比/數位變換電路（ADC)24、均衡器 30、位置設定電路35、PWM調變電路40和Η橋驅動器42。 其中，在聚焦控制電路1〇〇由單晶片LSI構成時，低通濾 波器22也可設置在晶片外。 差動放大電路20對位置檢測元件丨4(這裏為霍爾元 件）的輸出端-子間的電位差進行放大，並作為位置信號進行 輸出。該霍爾元件輸出與固定於透鏡10的礤鐵所產生的磁 場的磁通密度相應的電壓。若根據透鏡10的移動而磁通密 度發生變化，則該霍爾元件的輸出電壓也會與該變化成比 例地變化。因此，能夠根據該霍爾元件的輪出電壓來推測 透鏡10的位置。 低通濾波器22將從差動放大電路20輪出的位置信號 7 322170 201109809 的高頻成分除去。類比/數位變換電路24將從低通濾波器 22輸出的位置信號從類比值變換為數位值。 均衡器30基於根據位置檢測元件14的輸出信號確定 的當前的透鏡10的位置與由位置設定電路35設定的透鏡 10的位置之間的差分，生成用於使透鏡10的位置對位到 由位置設定電路35設定的位置的驅動信號，對驅動元件 12進行控制。 下面進行更具體的說明。均衡器30包括減法運算電 路31和伺服電路32。減法運算電路31計算從位置檢測元 件14輸出的位置信號與由位置設定電路35設定的位置信 號之間的差分，作為偏差信號輸出到伺服電路32。在透鏡 10的位置位於由位置設定電路35設定的位置時*該偏差 信號為零。伺服電路32生成用於消除從減法運算電路31 輸入的偏差信號的信號，並輸出到PWM調變電路40中。 當自動聚焦功能有效時，圖像信號處理部50經由I2C 接口等接口向位置設定電路35輸出用於使透鏡10的位置 依次變化的控制信號。 PWM調變電路40將從均衡器30輸入的信號變換為具 有與其數位值相應的占空比的脈衝信號。Η橋驅動器42至 少包括四個電晶體，透過使對角線上的兩個電晶體導通， 能夠使上述音圈馬達中流動電流。另外，透過使另一對角 線上的另外兩個電晶體導通，能夠使上述音圈馬達中流動 的電流的方向反向。 Η橋驅動器42以與從PWM調變電路40輸入的脈衝信 322170 201109809 號相應的電流方向及電流量使上述音亂馬達中流動電流， 從而使上述音圈馬達向規定方向移動規定距離。由此，能 夠使透鏡10向目標位置移動和收斂。 位置設定電路35若從圖像信號處理部50收到透鏡10 的目標位置的變更指示，則將從原目標位置到達新目標位 置為止這一範圍的多個位置依次設定到均衡器30中。更具 體而言，位置設定電路35為了使透鏡10逐漸從原目標位 置向新目標位置移動，生成階段性增加的多個位置，並依 次設定到均衡器30中（以下將這一連串處理所涉及的動作 記為步進移動動作）。此外，在要使透鏡10向相反方向移 動時，位置設定電路35生成階段性減少的多個位置，並依 次設定到均衡器30中。 產生上述多個位置的範圍並不嚴格劃分到原目標位 置與新目標位置之間的範圍，而設為包括原目標位置和新 目標位置附近的範圍。例如，上述多個位置中最後的位置 可以是超出新目標位置的位置。 第3圖是表示由位置設定電路35對均衡器30設定的 位置的推移例的圖。在此，考慮上述第一階段的掃描中該 位置的推移例。如上所述，圖像信號處理部50按透鏡10 的每個目標位置計算上述清晰度。即，從原目標位置向新 目標位置的一次移動與清晰度的一次計算判定為一組處 理。透過反復進行該一組處理，能夠確定清晰度為最大值 的位置。 上述一組處理需要在預先設定的一個聚焦判定期間 9 322170 201109809 内執行。若在透鏡10位於原目標位置的狀態下對均衡器 30設定新目標位置，則透鏡10將受到大的驅動力而急劇 移動，到透鏡10的移動收斂到新目標位置所需的時間較 長。該情況下，不能在一個聚焦判定期間内完成清晰度的 計算判定的可能性變高。 因此，在本實施方式中，為了使透鏡10緩慢移動， 透過上述步進移動動作使透鏡10移動。由此，如第3圖所 示’在一個聚焦判定期間的移動期間内，能夠使透鏡10 逐漸移動。 第4圖是用於說明由圖像信號處理部50對位置設定 電路35設定的參數的圖。在此，表示了上述一個聚焦判定 期間的移動期間内的透鏡位置的推移。狀態信號是在執行 上述步進移動動作時有效（在此為高位準）、在未執行該動 作時無效（在此為低位準）的信號。圖像信號處理部50透過 將該狀態信號設定為高位準來開始上述步進移動動作。若 ~步進移動動作結束，則位置設定電路35將該狀態信號設 定為低位準。 在母人變更透鏡1〇的目標位置時，圖像信號處理部 和0都向位^設定電路35發賴始位置、結束位置、步幅 更新間隔’作為上述控制信號。在每次變更透鏡1〇的目 知位置，A SE # 町位置攻定電路35都從圖像信號處理部50接受 恶 ° 、結束位置、步幅和更新間隔，並基於這些資訊 生成:均衡器30設定的位置。 以下進行更具體的說明。首先，位置設定電路35將 10 322170 201109809 該開始位置設定到均衡器30中。若從設定該開始位置開始 經過了該更新間隔，則位置設定電路35將在該開始位置上 加上該步幅後的位置設定到均衡器30中。若從設定該位置 開始經過了該更新間隔，則位置設定電路35將在該位置上 加上該步幅後的位置設定到均衡器30中。以下，到均衡器 30中設定的位置到達該結束位置為止反復進行上述處 理。位置設定電路3 5在將該結束位置設定到均衡器3 0中 之後結束一次步進移動動作。其中，在均衡器30中設定的 位置與該結束位置不一致的情況下，位置設定電路35將首 次超出該結束位置的位置設定到均衡器30中之後結束一 次步進移動動作。 此外，在上一次步進移動動作的結束位置與本次步進 移動動作的開始位置相同的情況下，可以省略圖像信號處 理部50向位置設定電路35提供開始位置的處理。另外， 在上一次步進移動動作的步幅和更新間隔與本次步進移動 動作的步幅和更新間隔相同的情況下，可以省略圖像信號 處理部50向位置設定電路35提供步幅和更新間隔的處理。 另外，圖像信號處理部50能夠對上述步幅設定極性 資訊（例如極性位元）。位置設定電路35在收到的步幅被設 定了極性資訊的情況下，在按照該極性的方向上更新對均 衡器30設定的位置，未設定該極性資訊的情況下，在預先 設定的方向（例如正方向）上更新對均衡器設定的位置。 如以上所說明的那樣，根據實施方式1，在實際地使 透鏡移動來確定焦點位置的自動聚焦控制中，能夠在不降 11 322170 201109809 低對焦精度的情況下縮短處理時間。即，在使透鏡1〇從原 目標位置向新目標位置移動時，透過依次對均衡器3〇輸入 階段性變化的多個位置信號’能夠使透鏡10逐漸向新目標 位置移動。因此，透鏡10的移動變緩，能夠縮短透鏡10 的移動收斂到新目標位置所需的時間。 在這一點上，若收斂時間變長，則需要在未收斂的狀 態下進>ί于上述清晰度的计具判定或等待到收斂為止，前者 的情況下會導致對焦精度降低’後者的情況下會導致處理 時間增加。 另外，在一個聚焦判定期間的移動期間内，應該對均 衡器30設定的多個位置並不是由圖像信號處理部生成 和設定的’而是由聚焦控制電路1〇0的位置設定電路35 生成和設定的，由此，與由圖像信號處理部5〇生成和設定 的情況相比能夠縮短處理時間。尤其是，若由專用的硬體 構成位置設定電路35 ’則與軟體處理相比能夠大幅度縮短 處理時間。 另外，由於在透鏡1〇收斂到各目標位置的狀態下計 算清晰度，因此能夠算出精度高的清晰度。透過以精度高 的清晰度為基礎來確定上述焦點位置，能夠提高對焦精度。 以上，基於幾個實施方式對本發明進行了說明。這些 實施方式是例示’本領域技術人員能夠理解，在其中各構 成要素和各處理步驟的組合上能夠實現各種變形例，I且 這樣的變形例也包括在本發明的範圍之内。 另外’在以上實施方式中，對在上述第一階段的掃描 12 322170 201109809 中應用上述步進移動動作的例子進行了說明，但也可應用 在上述第二階段的掃描中。另外，在以上實施方式中，對 以兩個階段的掃描進行對焦位置的確定處理的例子進行了 說明，但也可採用不劃分多個階段而進行一次掃描的方式 和進行三個階段以上的掃描的方式。上述步進移動動作能 夠應用到上述任一掃描之中。 另外，在以上實施方式中，驅動元件12被設為音圈 馬達，但也可採用壓電元件或步進電動機等。另外，位置 檢測元件14被設為霍爾元件，但也可採用MR元件或光屏 二極體（photo screen diode)等。另外，作為用於對驅動 元件12進行驅動的驅動電路，利用了 PWM調變電路40和 Η橋驅動器42，但在採用不是由脈衝信號而是由類比信號 驅動的驅動元件的情況下，作為其驅動電路，採用數位/ 類比變換電路和放大電路。 【圖式簡單說明】 第1圖是表示搭載了實施方式中的聚焦控制電路的攝 像裝置的結構圖。 第2圖是用於說明圖像信號處理部進行的透鏡的對焦 位置的確定處理的圖。 第3圖是表示由位置設定電路對均衡器設定的位置的 推移例的圖。 第4圖是用於說明由圖像信號處理部對位置設定電路 設定的參數的圖。 【主要元件符號說明】 13 322170 201109809 10 透鏡 12 驅動元件 14 位置檢測元件 16 攝像元件 20 差動放大電路 22 低通遽波器 24 類比/數位變換電路 30 均衡器 31 減法運算電路 32 伺服電路 35 位置設定電路 40 PWM調變電路 42 Η橋驅動器 50 圖像信號處理部 100 聚焦控制電路 500 攝像裝置201109809 VI. Description of the Invention: [Technical Field] The present invention relates to a focus control circuit that actually moves a lens to determine a focus position. [Prior Art] Most of the camera modules mounted in general digital cameras and mobile phones have an auto focus function. Most of the automatic focusing functions of such small cameras use the contrast detection method. The contrast detection method is a method in which the lens is actually moved, and the lens position at which the contrast of the subject in the captured image is maximized is detected, and the lens is moved to the position (for example, see Patent Document 1). . [Patent Document 1] Japanese Laid-Open Patent Publication No. 2006-166403. The contrast detection method can be realized at a lower cost than an active method in which infrared rays or ultrasonic waves are applied to a subject and the distance to the subject is measured based on the reflected waves. However, there is a problem that it takes time to search for the lens position at which the contrast of the subject is maximized. In a digital camera, it is desirable that the processing until the user focuses on the subject after pressing the shutter button halfway is completed in one second. However, the number of pixels of a camera module mounted in a general digital camera and a mobile phone has increased year by year, and these small cameras are gradually capable of capturing high-definition images. In high-definition images, focus deviation is easy to detect, and more precise autofocus control is required. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide an automatic focus control for moving a lens to determine a focus position in real 4 322170 201109809, which can reduce processing time without reducing focus accuracy in multiple sentences. Technology.. A focus control circuit according to an aspect of the present invention is mounted on an image pickup device including a lens, a drive element for adjusting a position of the lens, and a position detecting element for detecting a position of the lens, wherein the focus control circuit includes: equalization And generating a driving signal for aligning the position of the lens to the set position based on a difference between the position of the lens determined according to the output signal of the position detecting element and the set position, controlling the driving element; and When the setting unit receives an instruction to change the target position of the lens from the outside, the setting unit sequentially sets a plurality of positions in the range from the original target position to the new target position to the equalizer. Another aspect of the present invention is an image pickup apparatus. The apparatus includes: a lens; an image pickup element that converts light transmitted through the lens into an electric signal; a drive element for adjusting a position of the lens; a position detecting element for detecting a position of the lens; and the focus control circuit. (Effect of the Invention) According to the present invention, 'the automatic focus control for actually shifting the lens to determine the focus position' can shorten the processing time without lowering the focus accuracy. [Embodiment] FIG. 1 is a configuration diagram showing an imaging device 500 on which a focus control circuit 100 in an embodiment is mounted. The image pickup apparatus 500 includes a lens 10, a drive element 12, a position detecting element 14, an image pickup element 16, an image signal processing unit (ISP: Image Signal Processor) 50, and a focus control power 5 322170 201109809 road 100. Here, the structural elements irrelevant to the focus control by the image encoding engine are omitted. And the medium J and the automatic imaging element 16 convert the transmission number as an optical component into an electrical signal and output it to the image signal, and the component 16 can adopt (10) a sensor or a (10) image. . For the image pickup drive 70, the member 12 is an element for adjusting the position of the lens 10. The drive signal supplied from the focus control circuit 100 is in the optical axis direction < Thereby, the focal length of the lens 1 〇 and the image pickup element 16 is shifted: 2 The movable element 12 玎 uses a voice coil motor (VCM). The position detecting element 14 is a element 4 for detecting the position of the lens 1〇. The Hall element can be employed for the position detecting element 14. Below, yes. The position detecting element 14 and 12 are described by an example including a voice coil motor and a Hall element. The image signal processing unit processes the image signal output from the image pickup device 16. In the present embodiment, the focus position of the lens is fixed by the image signal mainly output from the image pickup device 16. The second drawing is a diagram for explaining the process of determining the in-focus position of the lens 1〇 by the image signal processing unit 50. When the shutter button is activated by the half-pressing or the like, the image signal processing unit 50 transmits a control signal for moving the lens 10 by a predetermined step to the focus control circuit 1A. At this time, the image signal processing unit 50 calculates the sharpness (sharPness) of each image signal imaged at each target position of the lens 10. For example, the edge component of each image signal can be extracted by high-pass filtering the image signals, and the edge components of the image signals can be accumulated to obtain the sharpness. Image signal area 322170 6 201109809 The unit 50 determines the position of the sharpness of the maximum value as the focus position. "," Figure 2 shows an example of determining the position of the confrontation by two-stage scanning. In the first stage of the sweep, the position of the Wei 1〇 is roughly changed, thereby locking the focus position of the lens 1G to Within a certain range, more specifically, the continuously increasing sharpness is converted to the target position at the time of reduction Μ - the range between the target positions is specified as the range in which the focus position of the lens 1〇 is. In the second stage In the sweeping, the position of the lens 10 is slightly changed within a range locked by the first-stage sweeping, and the position of the lens 10 having the maximum sharpness is determined as the in-focus position. The south speed still accurately searches for the in-focus position. Returning to Fig. 1, the focus control circuit 100 includes a differential amplifying circuit 20, a low pass filter 22, an analog/digital conversion circuit (ADC) 24, an equalizer 30, and a position. The setting circuit 35, the PWM modulation circuit 40, and the bridge driver 42. When the focus control circuit 1 is composed of a single-chip LSI, the low-pass filter 22 may be disposed outside the wafer. Position check The potential difference between the output terminal and the sub-element of the component 丨4 (here, the Hall element) is amplified and output as a position signal. The output of the Hall element corresponds to the magnetic flux density of the magnetic field generated by the yttrium iron fixed to the lens 10. If the magnetic flux density changes according to the movement of the lens 10, the output voltage of the Hall element also changes in proportion to the change. Therefore, the lens 10 can be estimated based on the wheel-out voltage of the Hall element. The low pass filter 22 removes the high frequency component of the position signal 7 322170 201109809 which is rotated from the differential amplifier circuit 20. The analog/digital conversion circuit 24 converts the position signal output from the low pass filter 22 from the analog value. The equalizer 30 generates a position pair for making the lens 10 based on the difference between the position of the current lens 10 determined based on the output signal of the position detecting element 14 and the position of the lens 10 set by the position setting circuit 35. The drive element 12 is controlled by a drive signal that is located at a position set by the position setting circuit 35. More specifically, the following description will be made. The arithmetic circuit 31 and the servo circuit 32. The subtraction circuit 31 calculates the difference between the position signal output from the position detecting element 14 and the position signal set by the position setting circuit 35, and outputs it as a deviation signal to the servo circuit 32. When the position is at the position set by the position setting circuit 35, the deviation signal is zero. The servo circuit 32 generates a signal for canceling the deviation signal input from the subtraction circuit 31, and outputs it to the PWM modulation circuit 40. When the focus function is enabled, the image signal processing unit 50 outputs a control signal for sequentially changing the position of the lens 10 to the position setting circuit 35 via an interface such as an I2C interface. The PWM modulation circuit 40 converts the signal input from the equalizer 30. It is a pulse signal having a duty ratio corresponding to its digital value. The bridge driver 42 includes at least four transistors that can cause current to flow in the voice coil motor by turning on the two transistors on the diagonal. Further, by turning on the other two transistors on the other diagonal line, the direction of the current flowing in the voice coil motor can be reversed. The bridge driver 42 causes a current to flow in the above-described noise motor in accordance with a current direction and a current amount corresponding to the pulse signal 322170 201109809 input from the PWM modulation circuit 40, thereby moving the voice coil motor by a predetermined distance in a predetermined direction. Thereby, the lens 10 can be moved and converged to the target position. When the position setting circuit 35 receives the instruction to change the target position of the lens 10 from the image signal processing unit 50, the position setting circuit 35 sequentially sets the plurality of positions in the range from the original target position to the new target position to the equalizer 30. More specifically, the position setting circuit 35 generates a plurality of positions which are gradually increased in order to gradually move the lens 10 from the original target position to the new target position, and sequentially set them to the equalizer 30 (hereinafter, the series of processes involved) The action is recorded as a step move action). Further, when the lens 10 is to be moved in the opposite direction, the position setting circuit 35 generates a plurality of positions which are gradually reduced, and is set to the equalizer 30 in order. The range in which the plurality of positions are generated is not strictly divided into the range between the original target position and the new target position, but is set to include the range near the original target position and the new target position. For example, the last of the plurality of locations may be a location that exceeds the new target location. Fig. 3 is a view showing an example of transition of the position set by the position setting circuit 35 to the equalizer 30. Here, an example of the transition of the position in the scanning of the first stage described above is considered. As described above, the image signal processing section 50 calculates the above-described sharpness for each target position of the lens 10. That is, one calculation of one movement and sharpness from the original target position to the new target position is determined as a set of processing. By repeating this set of processing, it is possible to determine the position where the sharpness is the maximum value. The above set of processing needs to be performed within a preset focus determination period 9 322170 201109809. If the new target position is set to the equalizer 30 in a state where the lens 10 is at the original target position, the lens 10 will be abruptly moved by a large driving force, and the time required for the movement of the lens 10 to converge to the new target position is long. In this case, the possibility that the calculation of the resolution cannot be completed within one focus determination period becomes high. Therefore, in the present embodiment, in order to move the lens 10 slowly, the lens 10 is moved by the step movement operation. Thereby, as shown in Fig. 3, the lens 10 can be gradually moved during the movement period of one focus determination period. Fig. 4 is a view for explaining parameters set by the image signal processing unit 50 to the position setting circuit 35. Here, the transition of the lens position in the movement period of the one focus determination period is shown. The status signal is a valid (here, high level) when performing the above step movement operation, and is invalid (here, low level) when the operation is not performed. The image signal processing unit 50 starts the step movement operation by setting the state signal to a high level. When the step movement operation is completed, the position setting circuit 35 sets the status signal to a low level. When the female person changes the target position of the lens 1〇, the image signal processing unit and 0 both send the start position, the end position, and the step update interval ’ to the position control circuit 35 as the above control signals. Each time the target position of the lens 1 is changed, the A SE # 位置 position attack circuit 35 receives the ° °, the end position, the stride, and the update interval from the image signal processing unit 50, and generates an equalizer based on the information. 30 set position. More specific explanations are given below. First, the position setting circuit 35 sets the start position of 10 322170 201109809 to the equalizer 30. When the update interval has elapsed from the setting of the start position, the position setting circuit 35 sets the position after the step is added to the start position to the equalizer 30. When the update interval has elapsed since the setting of the position, the position setting circuit 35 sets the position after the step is added to the position to the equalizer 30. Hereinafter, the above processing is repeated until the position set in the equalizer 30 reaches the end position. The position setting circuit 35 ends the one-step movement operation after setting the end position to the equalizer 30. However, when the position set in the equalizer 30 does not coincide with the end position, the position setting circuit 35 sets the position exceeding the end position for the first time to the equalizer 30, and ends the one-step movement operation. Further, when the end position of the previous step movement operation is the same as the start position of the current step movement operation, the processing in which the image signal processing unit 50 supplies the start position to the position setting circuit 35 can be omitted. In addition, in the case where the stride and update interval of the last step movement operation are the same as the step and update interval of the current step movement operation, the image signal processing unit 50 may be omitted from providing the step and the position setting circuit 35. Update interval processing. Further, the image signal processing unit 50 can set polarity information (e.g., polarity bits) for the above-described stride. When the received step is set with the polarity information, the position setting circuit 35 updates the position set to the equalizer 30 in the direction of the polarity, and if the polarity information is not set, in the preset direction ( For example, in the forward direction, the position set for the equalizer is updated. As described above, according to the first embodiment, in the autofocus control in which the lens is actually moved to determine the focus position, the processing time can be shortened without lowering the focus accuracy of 11 322170 201109809. That is, when the lens 1 is moved from the original target position to the new target position, the lens 10 can be gradually moved to the new target position by sequentially inputting a plurality of position signals ' that change stepwise to the equalizer 3'. Therefore, the movement of the lens 10 becomes gentle, and the time required for the movement of the lens 10 to converge to the new target position can be shortened. In this regard, if the convergence time becomes longer, it is necessary to advance the gauge of the above-described sharpness in the non-converged state or wait until convergence, and in the former case, the focus accuracy is lowered. This will result in an increase in processing time. Further, in the movement period of one focus determination period, the plurality of positions to be set to the equalizer 30 are not generated and set by the image signal processing section, but are generated by the position setting circuit 35 of the focus control circuit 1〇0. And the setting can thereby shorten the processing time compared with the case where it is generated and set by the image signal processing unit 5A. In particular, if the position setting circuit 35' is constituted by a dedicated hardware, the processing time can be significantly shortened compared to the soft processing. Further, since the sharpness is calculated in a state where the lens 1 〇 converges to each target position, it is possible to calculate sharpness with high precision. The focus accuracy can be improved by determining the above-described focus position based on the sharpness with high precision. The invention has been described above based on several embodiments. These embodiments are exemplified. It will be understood by those skilled in the art that various modifications can be made in the combination of the constituent elements and the various processing steps, and such modifications are also included in the scope of the present invention. Further, in the above embodiment, an example in which the above-described step movement operation is applied in the scanning of the first stage 12 322170 201109809 has been described, but it can also be applied to the scanning in the second stage described above. Further, in the above embodiment, an example has been described in which the focus position determination processing is performed in two stages of scanning, but a method of performing one scan without dividing a plurality of stages and performing three or more stages of scanning may be employed. The way. The above step movement action can be applied to any of the above scans. Further, in the above embodiment, the drive element 12 is set as a voice coil motor, but a piezoelectric element, a stepping motor or the like may be employed. Further, the position detecting element 14 is set as a Hall element, but an MR element, a photo screen diode, or the like can also be used. Further, as the drive circuit for driving the drive element 12, the PWM modulation circuit 40 and the bridge driver 42 are used, but in the case of using a drive element that is not driven by a pulse signal but by an analog signal, The drive circuit uses a digital/analog conversion circuit and an amplification circuit. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a configuration of an image pickup apparatus on which a focus control circuit in an embodiment is mounted. Fig. 2 is a view for explaining a process of determining a focus position of a lens by an image signal processing unit. Fig. 3 is a view showing an example of transition of the position set by the position setting circuit to the equalizer. Fig. 4 is a view for explaining parameters set by the image signal processing unit to the position setting circuit. [Main component symbol description] 13 322170 201109809 10 Lens 12 Driving element 14 Position detecting element 16 Imaging element 20 Differential amplifying circuit 22 Low-pass chopper 24 Analog/digital conversion circuit 30 Equalizer 31 Subtraction circuit 32 Servo circuit 35 Position Setting circuit 40 PWM modulation circuit 42 bridge driver 50 image signal processing unit 100 focus control circuit 500 imaging device