Lens drive systems and portable devices
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ASAHI KASEI MICRODEVICES CORP
- Filing Date
- 2026-01-21
- Publication Date
- 2026-08-05
Smart Images
Figure 2026127050000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a lens driving system and a portable device.
Background Art
[0002] Patent Document 1 discloses a method for controlling a plurality of cameras mounted on a portable device. [Prior Art Document] [Patent Document] [Patent Document 1] US Patent Application Publication No. 2022 / 0182546
Summary of the Invention
[0003] In a first embodiment of the present invention, a lens driving system is provided for controlling the relative position of a plurality of lenses with respect to an image sensor in a camera device, corresponding to a plurality of image sensors. The lens driving system may include a plurality of lens driving devices, each provided for the plurality of lenses, which control the relative position of the corresponding lens. In any of the above lens driving systems, each lens driving device may have a position detection unit that detects the current relative position of the corresponding lens. In any of the above lens driving systems, each lens driving device may have a calculation unit that calculates a drive amount for at least one of the lens and the image sensor based on a current position signal which is the output of the position detection unit and an input target position signal. In any of the above lens driving systems, each lens driving device may have a drive unit that drives at least one of the lens and the image sensor based on the drive amount. In any of the above lens driving systems, each lens driving device may have a signal processing unit that outputs a power control signal to control the power consumption of the position detection unit. In any of the above lens driving systems, each image sensor outputs detection data, and the system may control which image sensor's detection data is used to generate image data according to the state information of the camera device. In any of the above lens drive systems, the signal processing unit of at least one of the lens drive devices may change the power consumption of the position detection unit according to the state information of the camera device. At this time, the communication path of the lens drive device may be in an active state.
[0004] In any of the above lens drive systems, the signal processing unit may, depending on the state information, reduce the power consumption of the corresponding position detection unit to less than that of other position detection units. In this case, the drive unit may be operated to a state in which it can generate image data.
[0005] In any of the above lens drive systems, if the signal processing unit reduces the power consumption of the corresponding position detection unit to less than that of other position detection units, the power consumption of the corresponding drive unit may be maintained. In this case, the drive device may control the lens position to perform image stabilization, thereby generating image data from the image sensor.
[0006] In any of the above lens drive systems, if the signal processing unit reduces the power consumption of the corresponding position detection unit to less than that of other position detection units, the power consumption of the corresponding drive unit may be reduced. In this case, the drive device may control the lens position to perform image stabilization, thereby generating image data from the image sensor.
[0007] In any of the above lens drive systems, the signal processing unit may reduce the power consumption of the position detection unit by reducing the total time that the position detection unit operates to output the current position signal within a unit of time.
[0008] In any of the above lens drive systems, the signal processing unit may reduce the power consumption of the position detection unit by increasing the idle period during which the position detection unit does not perform the operation to output the current position signal within a unit of time.
[0009] In any of the above lens drive systems, the signal processing unit may reduce the power consumption of the position detection unit by shortening the conversion period during which the position detection unit operates to output one current position signal.
[0010] In any of the above lens driving systems, the plurality of lens driving devices may include a first lens driving device and a second lens driving device that control the relative position of the common lens. In any of the above lens driving systems, the power consumption of either the first lens driving device or the second lens driving device may be controlled to be less than the power consumption of the other, depending on the state information.
[0011] In any of the above lens drive systems, the position detection unit may be capable of continuous operation in which a conversion period in which it operates to output the current position signal is continuous, and intermittent operation in which a rest period in which it does not operate to output the current position signal is repeated with the conversion period. In any of the above lens drive systems, the signal processing unit may reduce power consumption by making the position detection unit perform the intermittent operation.
[0012] In any of the above lens drive systems, the repetition period obtained by adding one conversion period and one pause period in the intermittent operation may be less than or equal to the period during which the current position signal is output once in the continuous operation.
[0013] In any of the above lens drive systems, the signal processing unit may adjust at least one of the conversion period and the pause period so that the repetition frequency of repeating the conversion period and the pause period in the intermittent operation is equal to or greater than a preset frequency.
[0014] In any of the above lens drive systems, the set frequency may be greater than or equal to the upper limit of the audible frequency range.
[0015] In any of the above lens drive systems, the set frequency may be 10 kHz or higher.
[0016] In any of the above lens drive systems, the position detection unit may have a position sensor for detecting the relative position. In any of the above lens drive systems, the position detection unit may have an AD converter for converting the relative position into digital data. In any of the above lens drive systems, when the position detection unit is operated intermittently, the signal processing unit may increase the output rate by lowering the oversampling ratio of the AD converter compared to the case of continuous operation. Alternatively, the output rate may be maintained by lowering the oversampling ratio of the AD converter but providing the AD converter's idle period.
[0017] In any of the above lens drive systems, when the position detection unit is operated intermittently, the signal processing unit may lower the resolution of the AD converter and increase the output rate compared to the case of continuous operation. Alternatively, the output rate may be maintained by lowering the oversampling ratio of the AD converter but providing the AD converter's idle period.
[0018] In any of the above lens drive systems, the position detection unit may have a position sensor that detects the relative position and outputs a differential detection signal. In any of the above lens drive systems, the position detection unit may have a chopper modulator that modulates the polarity of the differential detection signal according to the chopping frequency. In any of the above lens drive systems, the position detection unit may have a differential amplifier that amplifies and outputs the output of the chopper modulator. In any of the above lens drive systems, the position detection unit may have a chopper demodulator that demodulates the output of the differential amplifier according to the chopping frequency. In any of the above lens drive systems, the position detection unit may have an AD converter that converts the detection signal output by the chopper demodulator into digital data. In any of the above lens drive systems, the signal processing unit may control the power consumption of the position detection unit by controlling the output rate of the AD converter. In any of the above lens drive systems, the amount of change in the chopping frequency before and after the change in the output rate of the AD converter may be smaller than the amount of change in the output rate.
[0019] In any of the above lens drive systems, the chopping frequency may be kept constant before and after the output rate of the AD converter changes.
[0020] In any of the above lens drive systems, the repetition frequency at which the conversion period and the pause period are repeated in the intermittent operation may be equal to or greater than the calculation frequency at which the calculation unit calculates the lens drive amount.
[0021] In any of the above lens drive systems, the position detection unit may have a high-speed intermittent mode in which the repetition frequency of repeating the conversion period and the pause period in the intermittent operation is equal to or greater than the audible frequency, and a low-speed intermittent mode in which the repetition frequency is less than the audible frequency. In any of the above lens drive systems, the signal processing unit may switch between the high-speed intermittent mode and the low-speed intermittent mode in response to an external signal.
[0022] A second embodiment of the present invention provides a portable device equipped with a camera device. In the portable device, the camera device may include a plurality of image sensors. In any of the portable devices, the camera device may include a plurality of lenses provided corresponding to the plurality of image sensors. In any of the portable devices, the camera device may include a lens drive system for controlling the relative position of the lenses with respect to the image sensors. In any of the portable devices, the lens drive system may include a plurality of lens drive devices provided corresponding to the plurality of lenses, each controlling the relative position of the corresponding lens. In any of the portable devices, each lens drive device may have a position detection unit for detecting the current relative position of the corresponding lens. In any of the portable devices, each lens drive device may have a calculation unit for calculating a drive amount for at least one of the lens and the image sensor based on a current position signal which is the output of the position detection unit and an input target position signal. In any of the portable devices, each lens drive device may have a drive unit for driving at least one of the lens and the image sensor based on the drive amount. In any of the portable devices, each lens drive device may have a signal processing unit for outputting a power control signal for controlling the power consumption of the position detection unit. In any of the above portable devices, each image sensor outputs detection data, and the system may control which image data from which image sensor is used to generate image data according to the state information of the camera device. In any of the above portable devices, the signal processing unit of at least one of the lens drive devices may change the power consumption of the position detection unit according to the state information.
[0023] Any of the above-mentioned portable devices may include a central control unit that controls the respective signal processing units based on the status information.
[0024] It should be noted that the above summary of the invention does not enumerate all of its features. Furthermore, subcombinations of these features may also constitute an invention.
Brief Description of the Drawings
[0025] [Figure 1] This is a diagram showing a configuration example of the mobile device 200 according to one embodiment of the present invention. [Figure 2] This is a diagram showing a configuration example of the camera device 100. [Figure 3] This is a diagram showing a configuration example of the lens driving device 120. [Figure 4] This is a diagram showing an operation example of the position detection unit 130. [Figure 5] This is a diagram showing another operation example of the position detection unit 130. [Figure 6] This is a diagram showing another operation example of the position detection unit 130. [Figure 7] This is a diagram showing a control example of the position detection unit 130. [Figure 8] This is a diagram showing another configuration example of the position detection unit 130. [Figure 9] This is a diagram showing a configuration example of the chopper modulator 133, the amplifier 134, and the chopper demodulator 135. [Figure 10] This is a diagram showing an example of the time waveform of the differential signals (Vampout, -Vampout) and the frequency spectrum. [Figure 11] This is a diagram showing an example of the time waveform of the detection signals (Vout, -Vout) and the frequency spectrum. [Figure 12] This is a diagram showing the frequency characteristics of the AD converter 136 and the chopping frequency when the output rate of the AD converter 136 is high or low. [Figure 13] This is a diagram showing another configuration example of the camera module 110.
Embodiments of the Invention
[0026] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of the features described in the embodiments are essential for the solution means of the invention.
[0027] Figure 1 shows an example configuration of a portable device 200 according to one embodiment of the present invention. The portable device 200 is equipped with a camera device 100. The portable device 200 may be an imaging device or a terminal such as a mobile phone. The portable device 200 in this example may further include at least one of a central control unit 202, a display device 204, a communication device 206, a communication path 210, and a storage device 208.
[0028] The central control unit 202 controls each component of the portable device 200, such as the camera device 100. The central control unit 202 is, for example, a processor such as a CPU. The central control unit 202 communicates with each component of the portable device 200 via the communication path 210, for example, by serial communication, parallel communication, network, or wireless communication. The signals transmitted by the central control unit 202 may be in the I2C (Inter-Integrated Circuit) format.
[0029] The display device 204 displays an image. The display device 204 may display an image captured by the camera device 100, or it may display other images. The communication device 206 communicates with external devices of the portable device 200 wirelessly or by other means. The communication device 206 may perform voice communication, or it may perform data communication including data other than voice. The storage device 208 stores information. The storage device 208 may store image data output by the camera device 100, or it may store other data.
[0030] The camera device 100 captures images and generates image data. The camera device 100 may have multiple camera modules. Each camera module may have a lens and an image sensor. For example, the camera device 100 may switch the camera module used to generate image data depending on the imaging magnification.
[0031] Figure 2 shows an example configuration of the camera device 100. In this example, the camera device 100 comprises multiple camera modules 110. In the example in Figure 2, two camera modules 110-1 and 110-2 are shown, but the camera device 100 may have more camera modules 110.
[0032] Each camera module 110 has a lens drive device 120, a lens 102, and an image sensor 108. In this specification, the multiple lens drive devices 120 provided in multiple camera modules 110 are collectively referred to as the lens drive system 150. The lens drive system 150 controls the relative position between the image sensor 108 and the lens 102 for the multiple lenses 102 provided in the camera device 100 corresponding to the multiple image sensors 108. The multiple lens drive devices 120 are provided corresponding to the multiple lenses 102 and each drives the relative position of the corresponding lens 102.
[0033] The lens 102 focuses light from the subject onto the image sensor 108. The image sensor 108 outputs detection data corresponding to the intensity of the received light. The image sensor 108 may have a plurality of light-receiving elements arranged in a two-dimensional array. Each light-receiving element outputs an electrical signal corresponding to the intensity of the received light. By combining these electrical signals, detection data representing a two-dimensional image is generated. The image sensor 108 is, for example, a CMOS image sensor or a CCD image sensor, but is not limited to these.
[0034] Image data is generated based on the detection data output by each image sensor 108. The generated image data may be displayed on the display device 204 as described above, or stored in the storage device 208. The camera device 100 controls which image sensor 108's detection data is used to generate the image data, according to the state information of the camera device 100.
[0035] Status information is information indicating, for example, the imaging magnification and imaging mode specified by the user. The imaging mode may include, for example, a normal imaging mode and a wide-angle imaging mode with different fields of view. The lens 102 and camera module 110 to be used are determined by the imaging magnification or imaging mode. The camera device 100 may use the detection data from the image sensor 108 in the camera module 110 corresponding to the status information as image data. The camera device 100 may generate image data by combining multiple detection data from two or more camera modules 110. The camera device 100 may further include a data selection unit that selects detection data according to the status information. In another example, the central control unit 202 may function as a data selection unit via the communication path 210.
[0036] The lens drive device 120 controls the relative position of the lens 102. In each example, the lens drive device 120 controls the relative position between the lens 102 and the image sensor 108 by moving the lens 102. However, the lens drive device 120 may move the image sensor 108, or it may move both the lens 102 and the image sensor 108. In this specification, the relative position of the lens 102 with respect to the image sensor 108 may be simply referred to as the lens position or the lens position.
[0037] The lens drive device 120 may control the focal position of the lens by controlling the position of the lens in a direction parallel to the optical axis of the lens, or it may control the position of the imaging range by controlling the position of the lens in a direction perpendicular to the optical axis of the lens. The lens drive device 120 may control the position of the lens 102 in response to operations from the user, etc., or it may automatically control the position of the lens 102, such as with autofocus or image stabilization.
[0038] The camera module 110 in this example further includes a driving element 106 and a driven element 104. The driving element 106 moves the lens 102 in response to control from the lens driving device 120. A driving element 106 may be provided for each direction in which the lens 102 is moved. The driving element 106 in this example is an element such as a coil that generates a magnetic field, but is not limited thereto. The lens driving device 120 may be provided as one for a plurality of driving elements 106, or it may be provided for each driving element 106.
[0039] The driven element 104 is fixed to the lens 102 either directly or indirectly via another component. The driven element 104 moves together with the lens 102 due to the magnetic field generated by the driving element 106, etc. In this example, the driven element 104 is, for example, a magnet, but is not limited to this. When the image sensor 108 is moved, the driven element 104 is fixed to the image sensor 108.
[0040] As described above, detection data to be used to generate image data is selected according to the status information of the camera device 100. On the other hand, in cases such as when the imaging magnification is changed sequentially, the selected detection data may switch according to the imaging magnification. Even in such cases, in order to continuously generate image data, camera modules 110 other than the currently selected camera module 110 also operate and generate detection data.
[0041] However, if multiple camera modules 110 are operating equally, power consumption will increase. The lens drive system 150 in this example changes the power consumption of at least one lens drive unit 120 based on the state information of the camera device 100. For example, it reduces the power consumption of the lens drive unit 120 in camera modules 110 other than the currently selected camera module 110 to less than the power consumption of the other lens drive units 120. This reduces the power consumption of the lens drive system 150. At this time, the communication path 210 between the central control unit 202 and each lens drive unit 120 may remain in an active state. "Active state" or "active" refers to a state in which at least one of the transmission and reception of information via the communication path 210 is possible. For example, a state in which communication is established between the central control unit 202 and the lens drive unit 120 via the communication path 210 may be considered an active state.
[0042] Figure 3 shows an example configuration of the lens drive device 120. The lens drive device 120 includes a position detection unit 130, a signal processing unit 122, a calculation unit 124, and a drive unit 126. The position detection unit 130, the signal processing unit 122, the calculation unit 124, and the drive unit 126 may be integrated and mounted on a single IC chip. The position detection unit 130 detects the current position of the corresponding lens 102 and outputs a current position signal CP. The corresponding lens 102 refers to the lens 102 controlled by the lens drive device 120. The position detection unit 130 may detect the position of the lens 102 by detecting the magnetic field from a magnet provided on the lens 102.
[0043] The signal processing unit 122 outputs a target position signal TP indicating the target position of the lens 102. The target position may be determined according to the user's operation, and may be automatically calculated by the signal processing unit 122 or the central control unit 202 using an autofocus or image stabilization function, etc. The target position may be input to the signal processing unit 122 from the central control unit 202, etc., via the communication path 210.
[0044] The calculation unit 124 calculates the drive amount for the lens 102 based on the input current position signal CP and target position signal TP. The calculation unit 124 may calculate the drive amount indicating the direction and magnitude of movement of the lens 102 from the difference between the current position and target position of the lens 102. The calculation unit 124 may, as an example, perform PID calculation. The calculation unit 124 may use proportional gain, integral gain, and differential gain, etc., as control parameters.
[0045] The drive unit 126 drives the lens 102 based on the drive amount input from the calculation unit 124. In this example, the drive unit 126 controls each drive element 106 according to the drive amount. For example, the drive unit 126 controls the magnetic field generated by each drive element 106 by controlling the current or voltage applied to each drive element 106, thereby driving the lens 102.
[0046] The signal processing unit 122 outputs a power control signal PC that controls the power consumption of the position detection unit 130. The signal processing unit 122 of at least one lens drive device 120 changes the power consumption of the position detection unit 130 according to the state information of the camera device 100. The signal processing unit 122 may make the power consumption of the corresponding position detection unit 130 smaller than that of other position detection units 130, according to the state information of the camera device 100. For example, the power consumption of the position detection unit 130 of a camera module 110 that is not used to generate image data may be controlled to be smaller than the power consumption of the position detection unit 130 of a camera module 110 that is used to generate image data. Such control can reduce the power consumption of the camera device 100. The central control unit 202 may generate a power control signal PC based on the state information and transmit it to each signal processing unit 122 via the communication path 210. In another example, the central control unit 202 may transmit the state information to the signal processing unit 122 via the communication path 210, and the signal processing unit 122 may generate a power control signal PC based on the state information.
[0047] The signal processing unit 122 may reduce the power consumption of the position detection unit 130 by controlling its operating period. The operating period of the position detection unit 130 refers to the period during which the position detection unit 130 is operating to generate the current position signal CP. The operating period of the position detection unit 130 may also refer to the period during which drive power is supplied to the position detection unit 130. The signal processing unit 122 may also reduce the power consumption of the position detection unit 130 by reducing the output frequency or update frequency of the current position signal CP in the position detection unit 130. In this case, the communication path 210 of the lens drive device 120 corresponding to the position detection unit 130 with reduced power consumption may be kept active. Furthermore, the drive unit 126 corresponding to the position detection unit 130 with reduced power consumption may be kept in a state where it can generate image data. In addition, the drive unit 126 may be kept in operation to perform image stabilization.
[0048] If the signal processing unit 122 reduces the power consumption of a corresponding position detection unit 130 to less than that of other position detection units 130, the power consumption of the corresponding drive unit 126 may be maintained. In other words, the drive unit 126 may continue to be supplied with power to control the position of the lens 102.
[0049] For example, the calculation unit 124 and the drive unit 126 control the position of the lens 102 according to the previous current position signal CP, even during periods when the position detection unit 130 does not newly detect the relative position of the lens 102 and the current position signal CP is not updated. In this case, the drive element 106 is supplied with power to generate a magnetic field, etc. As a result, although a slight control error occurs due to the decrease in the frequency of current position detection, the position of the lens 102 can be maintained generally correctly. Therefore, even when the camera module 110 used to generate image data is switched to the camera module 110, there is no need to move the position of the lens 102 significantly, and appropriate image data can be generated without delay. As a result, appropriate image data can be generated while reducing the power consumption of the camera device 100. In another example, if the signal processing unit 122 reduces the power consumption of the corresponding position detection unit 130 to be less than that of other position detection units 130, the power consumption of the corresponding drive unit 126 may also be reduced. This can further reduce power consumption.
[0050] The position detection unit 130 in this example includes a position sensor 132, an amplifier 134, and an AD converter 136. The position sensor 132 detects the lens position of the lens 102. The position sensor 132 is, for example, a silicon Hall element, a compound Hall element, or a magnetoresistive element.
[0051] The amplifier 134 amplifies and outputs the lens position signal output by the position sensor 132. The amplifier 134 may also be a buffer with an amplification factor of 1. The AD converter 136 converts the lens position signal detected by the position sensor 132 into digital data. The AD converter 136 outputs the current position signal CP, which is the lens position converted into digital data.
[0052] The signal processing unit 122 may control the power consumption of at least one of the position sensor 132, amplifier 134, and AD converter 136 according to the state information of the camera device 100. The signal processing unit 122 may control the power consumption of the position sensor 132 according to the state information of the camera device 100. For example, the signal processing unit 122 controls the frequency at which the position sensor 132 outputs or updates a signal indicating the lens position. The signal processing unit 122 may supply power to the position sensor 132 at the timing when the position sensor 132 should output a signal indicating the lens position. The signal processing unit 122 may control the period for which power is supplied to the position sensor 132 for position detection. The AD converter 136 may operate each time the position sensor 132 outputs a signal indicating the lens position and convert the signal into digital data.
[0053] The signal processing unit 122 may control the power consumption of the AD converter 136 according to the status information of the camera device 100. The power consumption of the AD converter 136 can be controlled by adjusting the length of time that the AD converter 136 is operating to perform AD conversion. Even if the operating period of the AD converter 136 is shortened, the period during which the position sensor 132 detects the lens position may be maintained and may be shortened in the same way as the operating period of the AD converter 136.
[0054] Figure 4 shows an example of the operation of the position detection unit 130. Figure 4 shows two operating modes with different power consumption. The first operating mode consumes more power than the second operating mode. In each operating mode, the position detection unit 130 sequentially outputs multiple current position signals CP. In Figure 4, the current position signals CP are shown as the outputs of the AD converter 136 [k (where k is n, n+1, n+2, ...)]. Each time the value of k at each output increases, the current position signal CP is updated according to the lens position detected by the position sensor 132.
[0055] In Figure 4, the period indicated by the output [k] of the AD converter 136 is the conversion period during which the AD converter 136 operates to generate the current position signal CP. For example, the period T1 in the first operating mode and the period T3 in the second operating mode are conversion periods. During the conversion period, the AD converter 136 operates at least partially according to the operating clock. For example, during the conversion period, the AD converter 136 may perform at least one of the following operations: a sampling operation that samples the amplitude value of the input analog signal, a quantization operation that generates discrete values according to the sampling result, and an encoding operation that converts the discrete values into a binary digital signal and outputs it.
[0056] In Figure 4, the period indicated as "pause" is a pause period during which the AD converter 136 is not operating to generate the current position signal CP. For example, period T4 in the second operating mode is a pause period. During the pause period, the AD converter 136 does not need to perform any of the sampling, quantization, and coding operations described above. The conversion period may be the period during which the AD converter 136 converts the current position signal CP corresponding to the lens position into a digital value. The pause period may also be the period during which the AD converter 136 does not output the current position signal CP corresponding to the lens position. During the pause period, the output of the AD converter 136 may maintain the value of the previous current position signal CP, or it may be a constant value (e.g., 0). During the pause period, the position sensor 132 may or may not detect the lens position.
[0057] In this example, the signal processing unit 122 reduces the power consumption of the position detection unit 130 by reducing the total time that the position detection unit 130 operates to convert the current position signal CP within a unit of time. In the example in Figure 4, the position detection unit 130 operates for a conversion period T1 to generate one current position signal CP. In the first operating mode of the position detection unit 130 in this example, the conversion periods for each current position signal CP are consecutive. Therefore, in the first operating mode, the total time that the position detection unit 130 operates within a unit of time (e.g., 2 × T1) is 2 × T1.
[0058] On the other hand, in the second operating mode, the position detection unit 130 operates to output one current position signal CP during a portion of the conversion period T3 within the same unit period (2 × T1), and remains idle during the remaining idle period T4. Therefore, in the second operating mode, the total time the position detection unit 130 operates within a unit of time is T3, which is smaller than the total time 2 × T1 in the first operating mode.
[0059] This process allows for control of the power consumption of the position detection unit 130. The signal processing unit 122 may also reduce the power consumption of the position detection unit 130 by increasing the pause period during which the position detection unit 130 does not operate to output the current position signal CP within a unit time. In the example shown in Figure 4, the pause period within a unit time (2 × T1) in the first operating mode is 0, while the pause period within a unit time in the second operating mode is T4. The pause period in the first operating mode does not have to be 0. The pause period T4 within a unit time in the second operating mode may be more than half of the unit time (2 × T1).
[0060] Figure 4 shows the continuous operation mode as the first operating mode and the intermittent operation mode as the second operating mode. In the continuous operation mode, the conversion period T1 for multiple current position signals CP is continuous. That is, in the continuous operation mode, there is no pause period between the conversion period T1 of two current position signals CP. For example, if the position detection unit 130 such as the AD converter 136 operates according to the period of the operating clock, the pause period may be longer than one period of the operating clock. In the continuous operation mode, there is no pause period longer than one period of the operating clock between the two conversion periods T1. In the continuous operation mode, the sampling, quantization, and encoding operations for the two current position signals CP may be performed continuously without any pause periods in between.
[0061] In intermittent operation mode, the position detection unit 130 alternately repeats a conversion period T3 and a pause period T4. The pause period T4 is longer than one cycle of the operation clock described above. The length of the pause period T4 may be 25% or more of the length of the conversion period T3, or it may be 50% or more. In the example in Figure 4, the signal processing unit 122 reduces power consumption by making the position detection unit 130 operate intermittently.
[0062] Figure 5 shows another example of the operation of the position detection unit 130. The operation of the position detection unit 130 in the first operating mode is the same as in the example in Figure 4. In this example, the signal processing unit 122 reduces the power consumption of the position detection unit 130 by shortening the conversion period T3 during which the position detection unit 130 operates to output one current position signal CP in the second operating mode.
[0063] In this example as well, the position detection unit 130 in the second operating mode operates intermittently by alternately repeating a conversion period T3 and a pause period T4. The repetition period T2, which is the sum of one conversion period T3 and one pause period T4 in the intermittent operation, may be less than or equal to the conversion period T1 in continuous operation, which outputs one current position signal. The repetition period T2 may be the same as the conversion period T1. In this case, the period in which the current position signal CP is updated is the same in both the continuous operation mode and the intermittent operation mode. The conversion period T3 may be half or less of the conversion period T1. The repetition period T2 may be shorter than the conversion period T1. The repetition period T2 may be half or less of the conversion period T1.
[0064] The repetition frequency is the frequency at which the conversion period T3 and the pause period T4 are repeated in intermittent operation mode. The repetition frequency is the reciprocal of the repetition period (e.g., T2). In continuous operation mode, the reciprocal of the conversion period T1 is used as the repetition frequency. In the example shown in Figure 4, the repetition frequency in intermittent operation mode is smaller than the repetition frequency in continuous operation mode. Since the repetition frequency corresponds to the control frequency of the lens 102, a smaller repetition frequency results in a smaller control frequency for the lens 102. A smaller control frequency for the lens 102 may result in the control sound of the lens 102 becoming audible to the user. From the perspective of the calculation unit 124, when the position detection unit 130 is operating based on the repetition frequency, a signal corresponding to the actual detected position information of the lens 102 (called the real signal) and a signal corresponding to the situation where the position detection unit 130 has stopped operating (called the dummy signal) are input alternately. From a system-wide perspective, this state can be seen as equivalent to the calculation unit 124 and the drive unit 126 resolving the difference between the actual signal and the dummy signal. This operation is the cause of the control sound generated by the lens 102. Therefore, by controlling the repetition frequency band, it becomes possible to control the generation band of the control sound originating from the actual signal and the dummy signal.
[0065] The signal processing unit 122 may adjust at least one of the conversion period T3 and the pause period T4 so that the repetition frequency in intermittent operation is equal to or greater than a preset frequency. For example, as shown in Figure 5, the decrease in repetition frequency can be suppressed by setting the conversion period T3 and the pause period T4 to a shorter value. The preset frequency may be equal to or greater than the upper limit of the human audible frequency range. The audible frequency range may be 20 Hz or more and 20 kHz or less. In this case, the upper limit is 20 kHz. The preset frequency may also be 10 kHz or more. The preset frequency may also be 16 kHz or more and 20 kHz or more. Such control can suppress the sound of the lens 102 being heard by the user or others.
[0066] The repetition frequency in intermittent operation may be higher than or equal to the calculation frequency at which the calculation unit 124 calculates the lens drive amount. The calculation frequency in the calculation unit 124 refers to the frequency at which the calculation unit 124 updates the lens drive amount. When the lens drive amount is updated, the drive unit 126 controls the position of the lens 102. Therefore, the calculation frequency in the calculation unit 124 corresponds to the control frequency that controls the lens 102. In order to prevent the control sound of the lens 102 from occurring in the audible range, the calculation frequency in the calculation unit 124 may be set higher than the upper limit of the audible frequency. By setting the repetition frequency in the position detection unit 130 to be higher than or equal to the calculation frequency, the repetition frequency can be set higher than the audible frequency.
[0067] The conversion period T3 can be shortened by reducing the accuracy of the AD conversion in the AD converter 136. For example, if the AD converter 136 is an oversampling or ΔΣ modulation AD converter 136, the output rate of the AD converter 136 can be increased by lowering the oversampling ratio. The output rate is, for example, represented by the reciprocal of the conversion period T3. In an oversampling AD converter 136, the lens position signal is sampled with a significantly larger number of samples than the number of samples corresponding to the Nyquist rate. The higher the number of samples (the higher the oversampling ratio), the higher the resolution of the output current position signal. The resolution of a digital signal is represented by the number of bits corresponding to values larger than the quantization error component.
[0068] On the other hand, the more samples there are, the longer the time required to generate one current position signal (conversion period T3). When the position detection unit 130 is operated intermittently, the signal processing unit 122 may lower the oversampling ratio of the AD converter 136 and increase the output rate compared to continuous operation. When the position detection unit 130 is operated intermittently, the signal processing unit 122 may lower the resolution of the AD converter 136 and increase the output rate compared to continuous operation.
[0069] The resolution of the AD converter 136 can be adjusted by the oversampling ratio described above, but it may also be adjusted by other methods. The AD converter 136 may be a Nyquist-type AD converter. In a Nyquist-type AD converter, the input signal is sampled at the Nyquist frequency. Even in a Nyquist-type AD converter 136, the resolution of the AD converter 136 can be reduced and the output rate increased by reducing the number of times the input signal is sampled to generate one current position signal.
[0070] Figure 6 shows another example of operation of the position detection unit 130. The position detection unit 130 in this example has a low-speed intermittent operation mode and a high-speed intermittent operation mode as second operation modes. In the low-speed intermittent operation mode, the repetition frequency (1 / T2) is smaller than the set frequency described above. In the high-speed intermittent operation mode, the repetition frequency (1 / T2) is greater than or equal to the set frequency described above. The set frequency is, for example, the upper limit of the audible frequency. The low-speed intermittent operation mode may be the same as the second operation mode in Figure 4, and the high-speed intermittent operation mode may be the same as the second operation mode in Figure 5.
[0071] The signal processing unit 122 may switch between high-speed intermittent operation mode and low-speed intermittent operation mode depending on an external signal. The external signal is a signal input from outside the signal processing unit 122. The external signal may be input from the central control unit 202 via the communication path 210. The external signal may be generated, for example, in response to user operations. For example, if the user is not concerned with noise, the low-speed intermittent operation mode may be selected. Alternatively, the low-speed intermittent operation mode may be implemented to allow the user to determine by sound whether or not the intermittent operation mode is functioning.
[0072] Figure 7 shows an example of the control of the position detection unit 130. In this example, the signal processing unit 122 controls power consumption by adjusting the conversion accuracy of the AD converter 136, as described above. The signal processing unit 122 may generate a power control signal PC2 that adjusts at least one of the oversampling ratio, sampling rate, resolution, and output rate of the AD converter 136. In this example as well, the signal processing unit 122 may generate a power control signal PC1 that controls the power consumption of the position sensor 132.
[0073] Figure 8 shows another example of the configuration of the position detection unit 130. In this example, the position detection unit 130 further includes a chopper modulator 133 and a chopper demodulator 135 in addition to the configuration shown in Figure 3. Also, the amplifier 134 in this example is a differential amplifier.
[0074] Figure 9 shows an example configuration of a chopper modulator 133, an amplifier 134, and a chopper demodulator 135. In this example, the position sensor 132 detects the lens position and outputs differential detection signals (Vin, -Vin).
[0075] The chopper modulator 133 modulates the polarity of the differential detection signals (Vin, -Vin) according to the chopping frequency. In this example, the chopper modulator 133 outputs the detection signal Vin as the output signal Vn when the chopping clock CLK1 is high logic and the chopping clock CLK2 is low logic, and outputs the inverted detection signal -Vin when the chopping clock CLK1 is low logic and the chopping clock CLK2 is high logic. The chopping clock CLK2 is a clock obtained by inverting the waveform of the chopping clock CLK1. The chopper modulator 133 outputs the detection signal Vin as the output signal -Vn when the chopping clock CLK1 is low logic and the chopping clock CLK2 is high logic, and outputs the inverted detection signal -Vin when the chopping clock CLK1 is high logic and the chopping clock CLK2 is low logic.
[0076] Amplifier 134 amplifies the differential signals (Vampin, -Vampin) output by chopper modulator 133 with an amplification factor of 1 or more to output differential signals (Vampout, -Vampout). Chopper demodulator 135 demodulates the output of amplifier 134 according to the chopping frequency. In this example, chopper demodulator 135 outputs the differential signal -Vampout as a detection signal Vout when chopping clock CLK1 is high logic and chopping clock CLK2 is low logic, and outputs the differential signal Vampout when chopping clock CLK1 is low logic and chopping clock CLK2 is high logic. In this example, the AD converter 136 converts the differential detection signals (Vout, -Vout) output by the chopper demodulator 135 into digital data.
[0077] Figure 10 shows an example of the time waveform and frequency spectrum of a differential signal (Vampout, -Vampout). The differential signal (Vampout, -Vampout) is an amplified signal of the differential signal (Vampin, -Vampin). In this case, the amplifier offset and noise components are also amplified.
[0078] Figure 11 shows an example of the time waveform and frequency spectrum of the detection signal (Vout, -Vout). The detection signal (Vout, -Vout) corresponds to the amplified signal of the detection signal (Vin, -Vin). Therefore, the detection signal (Vout, -Vout) has a peak at frequency ωin. On the other hand, the noise component is shifted to a high-frequency band corresponding to the chopping frequency ωc. Therefore, a low-pass filter can be used to remove the noise component that has been shifted to the high-frequency band, and the frequency components of the detection signal (Vout, -Vout) can be extracted.
[0079] As described above, the signal processing unit 122 may control the power consumption of the position detection unit 130 by controlling the output rate of the AD converter 136. In this case, the amount of change in the chopping frequency before and after the change in the output rate of the AD converter 136 may be smaller than the amount of change in the output rate.
[0080] Figure 12 shows the frequency characteristics and chopping frequency of the AD converter 136 when the output rate of the AD converter 136 is high or low. The chopping frequency may be kept constant before and after the output rate of the AD converter 136 changes. With this control, even if the power consumption of the position detection unit 130 is reduced, the chopper modulation frequency is maintained, so that the offset of the detection signal and noise components in the low frequency band can be accurately removed.
[0081] Figure 13 shows another example configuration of the camera module 110. The camera module 110 in this example includes a first lens drive device 120-a and a second lens drive device 120-b that drive a common lens 102. In this example, the camera module 110 may have a lens drive device 120 for each drive element 106. The other structures are the same as in the example in Figure 2. Also, the structure of each lens drive device 120 is the same as in any of the examples described in Figures 2 to 12.
[0082] In this example as well, depending on the status information of the camera device 100, the power consumption of either the first lens drive unit 120-a or the second lens drive unit 120-b may be controlled to be less than the power consumption of the other. For example, when the camera module 110 is not being used to generate image data, the signal processing unit 122 may reduce the power consumption of either the first lens drive unit 120-a or the second lens drive unit 120-b. In other examples, the power consumption of both the first lens drive unit 120-a and the second lens drive unit 120-b may be reduced.
[0083] The central control unit 202 may decide which of the first lens drive unit 120-a and the second lens drive unit 120-b to reduce power consumption in accordance with state information. In this example, the state information may include detection data generated by the image sensor 108 when both the first lens drive unit 120-a and the second lens drive unit 120-b are operated at low power consumption. Based on this detection data, the central control unit 202 may decide which of the first lens drive unit 120-a and the second lens drive unit 120-b to operate at low power consumption in the future. For example, the central control unit 202 may detect in which direction the noise contained in the image of the detection data, which has increased due to the operation of the lens drive unit 120 at low power consumption, is continuously present in the image. The central control unit 202 may reduce the power consumption of the lens drive unit 120 that controls the lens 102 in a direction different from the direction of the noise. This makes it possible to reduce the power consumption in the camera module 110 while suppressing the increase in noise contained in the image of the detection data.
[0084] As a variation of the embodiment described above, the lens drive system 150 may have a calculation unit 124 mounted on the central control unit 202. In this case, each lens drive device 120 may have a signal processing unit 122, a drive unit 126, and a position detection unit 130. This variation is a lens drive system that controls the relative position of lenses (e.g., lenses 102-1, 102-2) with respect to a plurality of image sensors (e.g., image sensors 108-1, 108-2) in a camera device 100, and comprises a plurality of lens drive devices (e.g., lens drive devices 120-1, 120-2) provided for each of the plurality of lenses, which control the relative position of each corresponding lens, and may be the same as the other embodiments described herein.
[0085] Each lens drive unit 120 also includes a position detection unit 130 that detects the current relative position of the corresponding lens 102, a drive unit 126 that drives at least one of the lens 102 and the image sensor 108 based on the drive amount, and a signal processing unit 122 that outputs a power control signal to control the power consumption of the position detection unit 130. Furthermore, each image sensor 108 outputs detection data, the communication path 210 of the lens drive unit 120 is active, and the system controls which image data from which image sensor 108 is used to generate image data according to the state information of the camera device, and the signal processing unit 122 of at least one lens drive unit 120 changes the power consumption of the position detection unit 130 according to the state information, as in other embodiments described herein.
[0086] In another modified example, the central control unit 202 acquires a current position signal from each lens drive unit 120, derives a drive amount for at least one of the lens 102 and the image sensor 108 based on the current position signal and the target position signal, and transmits the derived drive amount to each lens drive unit 120. Each lens drive unit 120 receives its own drive amount via the communication path 210, and the drive unit 126 operates according to the received drive amount. The communication path 210 is preferably a communication bus that supports I2C or a communication standard that supports higher speed communication, such as I3C (Improved Inter-Integrated Circuit).
[0087] In the modified example, the calculation unit 124 may be implemented as software executed by the central control unit 202, or it may be implemented as an IC chip externally attached to the central control unit 202. Also in the modified example, for each lens drive device 120, the signal processing unit 122, the drive unit 126, and the position detection unit 130 may be integrated into a single IC chip.
[0088] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.
[0089] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before," "prior to," etc., and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," "next," etc. for convenience, it does not mean that it is essential to perform the operations in that order. [Explanation of Symbols]
[0090] 100...Camera device, 102...Lens, 104...Driven element, 106...Driver element, 108...Image sensor, 110...Camera module, 120...Lens drive device, 122...Signal processing unit, 124...Calculation unit, 126...Drive unit, 130...Position detection unit, 132...Position sensor, 133...Chopper modulator, 134...Amplifier, 135...Chopper demodulator, 136...AD converter, 150...Lens drive system, 200...Portable device, 202...Central control unit, 204...Display device, 206...Communication device, 208...Storage device, 210...Communication path
Claims
1. A lens drive system for controlling the relative position of multiple lenses with respect to an image sensor in a camera device, wherein the lenses are provided to correspond to multiple image sensors, The system includes a plurality of lens driving devices provided in accordance with the plurality of lenses, each controlling the relative position of the corresponding lens, Each lens drive device is A position detection unit that detects the current relative position of the corresponding lens, A calculation unit calculates the drive amount of at least one of the lens and the image sensor based on the current position signal which is the output of the position detection unit and the input target position signal. A drive unit that drives at least one of the lens and the image sensor based on the aforementioned drive amount, A signal processing unit that outputs a power control signal to control the power consumption of the position detection unit. It has, Each image sensor outputs detection data, and the communication path of the lens drive device is activated, controlling which image data from which image sensor is used to generate image data according to the status information of the camera device. The signal processing unit of at least one of the lens drive devices changes the power consumption of the position detection unit according to the state information. Lens drive system.
2. The signal processing unit reduces the power consumption of the corresponding position detection unit to less than that of other position detection units, according to the state information, while keeping the drive unit running to enable the generation of image data. The lens drive system according to claim 1.
3. The signal processing unit reduces the power consumption of the corresponding position detection unit to less than that of other position detection units, according to the state information, while the drive unit operates to perform image stabilization. The lens drive system according to claim 2.
4. When the signal processing unit reduces the power consumption of the corresponding position detection unit to less than that of other position detection units, the power consumption of the corresponding drive unit is maintained. The lens drive system according to claim 2.
5. When the signal processing unit reduces the power consumption of the corresponding position detection unit to less than the power consumption of other position detection units, the power consumption of the corresponding drive unit is also reduced. The lens drive system according to claim 2.
6. The signal processing unit reduces the power consumption of the position detection unit by reducing the total time that the position detection unit operates to output the current position signal within a unit of time. The lens drive system according to claim 2.
7. The signal processing unit reduces the power consumption of the position detection unit by increasing the idle period during which the position detection unit does not perform the operation to output the current position signal within a unit of time. The lens drive system according to claim 2.
8. The signal processing unit reduces the power consumption of the position detection unit by shortening the conversion period during which the position detection unit operates to output one current position signal. The lens drive system according to claim 6.
9. The plurality of lens driving devices include a first lens driving device and a second lens driving device that control the relative positions of the common lenses. Depending on the state information, the power consumption of either the first lens drive unit or the second lens drive unit is controlled to be less than the power consumption of the other. The lens drive system according to claim 2.
10. The position detection unit is capable of continuous operation in which it operates for a conversion period to output the current position signal, and intermittent operation in which it repeats a period of inactivity in which it does not operate for outputting the current position signal and the conversion period. The signal processing unit reduces power consumption by causing the position detection unit to operate intermittently. A lens drive system according to any one of claims 1 to 9.
11. The repetition period obtained by adding one conversion period and one pause period in the intermittent operation is less than or equal to the period during which the current position signal is output once in the continuous operation. The lens drive system according to claim 10.
12. The signal processing unit adjusts at least one of the conversion period and the pause period so that the repetition frequency of repeating the conversion period and the pause period in the intermittent operation is equal to or greater than a preset frequency. The lens drive system according to claim 11.
13. The aforementioned set frequency is above the upper limit of the audible frequency range. The lens driving system according to claim 12.
14. The aforementioned set frequency is 10 kHz or higher. The lens driving system according to claim 12.
15. The position detection unit is, A position sensor for detecting the relative position, A converter that converts the aforementioned relative position into digital data It has, When the position detection unit operates intermittently, the signal processing unit lowers the oversampling ratio of the AD converter and increases the output rate compared to the continuous operation case. The lens drive system according to claim 10.
16. The position detection unit is, A position sensor for detecting the relative position, A converter that converts the aforementioned relative position into digital data It has, When the position detection unit operates intermittently, the signal processing unit lowers the resolution of the AD converter and increases the output rate compared to the continuous operation case. The lens drive system according to claim 10.
17. The position detection unit is, A position sensor that detects the relative position and outputs a differential detection signal, A chopper modulator that modulates the polarity of the differential detection signal according to the chopping frequency, A differential amplifier that amplifies and outputs the output of the chopper modulator, A chopper demodulator that demodulates the output of the differential amplifier according to the chopping frequency, The AD converter converts the detection signal output by the chopper demodulator into digital data. It has, The signal processing unit controls the power consumption of the position detection unit by controlling the output rate of the AD converter. The amount of change in the chopping frequency before and after the change in the output rate of the AD converter is smaller than the amount of change in the output rate. The lens drive system according to claim 10.
18. The chopping frequency is kept constant before and after the output rate of the AD converter changes. The lens drive system according to claim 17.
19. In the aforementioned intermittent operation, the repetition frequency at which the conversion period and the pause period are repeated is equal to or greater than the calculation frequency at which the calculation unit calculates the drive amount of the lens. The lens drive system according to claim 10.
20. The position detection unit has a high-speed intermittent mode in which the repetition frequency of repeating the conversion period and the pause period in the intermittent operation is equal to or greater than the audible frequency, and a low-speed intermittent mode in which the repetition frequency is less than the audible frequency. The signal processing unit switches between the high-speed intermittent mode and the low-speed intermittent mode in response to an external signal. The lens drive system according to claim 10.
21. A portable device equipped with a camera, The camera device is Multiple image sensors and Multiple lenses provided corresponding to the multiple image sensors, A lens drive system that controls the relative position of the lens with respect to the image sensor. Equipped with, The lens driving system comprises a plurality of lens driving devices provided in accordance with the plurality of lenses, each controlling the relative position of the corresponding lens. Each lens drive device is A position detection unit that detects the current relative position of the corresponding lens, A calculation unit calculates the drive amount of at least one of the lens and the image sensor based on the current position signal which is the output of the position detection unit and the input target position signal. A drive unit that drives at least one of the lens and the image sensor based on the aforementioned drive amount, A signal processing unit that outputs a power control signal to control the power consumption of the position detection unit. It has, Each image sensor outputs detection data, the communication path of the lens drive device is active, and the system controls which image data from which image sensor is used to generate image data according to the status information of the camera device. The signal processing unit of at least one of the lens drive devices changes the power consumption of the position detection unit according to the state information. Portable devices.
22. The system further comprises a central control unit that controls each of the signal processing units based on the aforementioned state information. The portable device according to claim 21.