KR20150057786A - camera module - Google Patents

Abstract

An optical image stabilization (OIS) apparatus according to an embodiment of the present invention comprises a magnet arranged around a lens; a coil including arranged to be separated from the magnet, and including a first terminal and a second terminal; and a driving IC electrically connected with the first terminal and the second terminal, electrically connected with an image sensor, and outputting a pulse width modulation (PMW) signal to the first terminal and the second terminal based on a synchronizing signal received from the image sensor.

Description

Camera module {CAMERA MODULE}

The present invention relates to a camera module, and more particularly, to an OIS (Optical Image Stabilizatin) device of a camera module.

The OIS (Optical Image Stabilization) device is an image stabilization device that compensates for camera shake during camera shooting. OIS devices are applied not only to general camera modules but also to cameras built in mobile terminals.

The OIS device includes a magnet disposed around the lens and a coil disposed apart from the magnet. When a current flows through the coil, a magnetic field is formed between the coil and the magnet to move the lens and correct the camera shake.

As a method of applying voltage to the coil of the driving IC, there are a linear method and a PWM (Pulse Width Modulation) method. According to the linear method, the current flowing through the coil can be finely adjusted, but there is a problem of high power consumption.

In the case of a camera built in a portable terminal, since it is necessary to minimize power consumption, a PWM method capable of reducing power consumption can be applied.

However, when a voltage is applied to the coil by the PWM method, the voltage applied to the coil may generate magnetic flux around the image sensor and act as a noise.

An object of the present invention is to provide an OIS device of a camera module.

An OIS (Optical Image Stabilization) apparatus according to an embodiment of the present invention includes: a magnet disposed around a lens; a coil spaced from the magnet, the coil including a first terminal and a second terminal; And a driving IC that is electrically connected to the second terminal and is electrically connected to the image sensor and outputs a PWM (Pulse Width Modulation) signal to the first terminal and the second terminal based on the synchronization signal received from the image sensor. .

At least one of the rising and falling edges of the PWM signal may not overlap the ADC readout period of the image sensor.

At least one of a rising edge and a falling edge of the PWM signal may be synchronized with the synchronization signal.

At least one of a rising edge of the PWM signal and at least one of rising edges of the synchronization signal coincide with each other or at least one of falling edges of the PWM signal and a falling edge of the synchronization signal may coincide with each other.

The synchronization signal may include at least one of a horizontal synchronization signal Hsync, a vertical synchronization signal Vsync, a pixel clock signal, an ADC synchronization signal, and an image input clock signal of the image sensor.

A camera module according to an exemplary embodiment of the present invention includes a printed circuit board, an image sensor electrically connected to the printed circuit board, a plurality of lenses sequentially formed on the image sensor, Wherein the OIS device comprises: a magnet disposed around the lens; a coil spaced from the magnet, the coil including a first terminal and a second terminal; and an optical image stabilization (OIS) And a PWM (Pulse Width Modulation) signal is output to the first terminal and the second terminal based on a synchronization signal received from the image sensor, the PWM signal being electrically connected to the first terminal and the second terminal Driving IC.

Wherein the plurality of lenses are arranged in a first axial direction, the OIS device includes a first magnet and a first coil arranged in a second axial direction perpendicular to the first axial direction, And a second magnet and a second coil arranged in a third axial direction perpendicular to the biaxial direction.

Wherein the image sensor comprises at least one first pin and the OIS device comprises at least one second pin and wherein the image sensor and the OIS device are electrically connected via the first pin and the second pin .

The synchronization signal may be output from the first pin and input to the second pin.

An OIS device according to an embodiment of the present invention includes a magnet disposed around a lens, a coil spaced from the magnet and including a first terminal and a second terminal, and a coil electrically connected to the first terminal and the second terminal, And a driving IC for outputting a PWM (Pulse Width Modulation) signal to the first terminal and the second terminal, wherein a raising edge or a falling edge of the PWM signal is connected to the image sensor And does not overlap the analog-to-digital converter (ADC) readout section of FIG.

The ADC readout interval may include a sampling interval of a reference signal for the ADC of the image sensor.

According to an embodiment of the present invention, the influence of the PWM signal for the OIS device on the image sensor can be minimized. Thus, the noise on the image can be reduced.

1 shows a camera module including an OIS (Optical Image Stabilization) apparatus according to an embodiment of the present invention.
Fig. 2 shows an example of an OIS device, and Fig. 3 shows a voltage applied to the coil in accordance with the drive IC output of Fig.
4 shows an example of an image sensor included in the camera module.
5 shows an ADC (Analog to Digital Converter) included in the image sensor of FIG.
FIG. 6 illustrates a method of sensing the brightness of light using the image sensor of FIG.
7 specifically shows the influence of the PWM signal outputted from the driving IC of the OIS device on the operation of the image sensor.
8 shows an example in which the ADC readout period and the rising edge or the falling edge of the PWM signal do not overlap.
9 shows an example in which the ADC readout period and the PWM rising edge or falling edge are synchronized.
10 shows an image sensor and a driving IC according to an embodiment of the present invention.
11 to 12 show an example in which the driving IC outputs the PWM signal using the synchronous signal received from the image sensor according to an embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 shows a camera module including an OIS (Optical Image Stabilization) apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the camera module 100 includes a printed circuit board (PCB) 110, an image sensor 120 disposed on the PCB 110 and electrically connected to the PCB 110, And a plurality of lenses 130 and an OIS device 140 that are arranged on the object side 120 and are arranged sequentially from the object side to the image side.

The image sensor 120 may be connected to the PCB 110 by flip chip bonding or wire bonding. The image sensor 120 may be, for example, a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor) sensor. The image sensor 120 can receive light incident through a plurality of lenses 130 and generate an image signal. The image signal generated by the image sensor 120 may be transmitted to an external device electrically connected through a circuit pattern formed on the PCB 110 and displayed as an image.

The lens 130 collects or diverges the light incident from the object side to make an optical image. The lens 130 may be classified into a plastic lens, a glass lens, a polymer lens, or the like depending on, for example, a material. The lens 130 may be divided into a spherical lens or an aspherical lens.

Although not shown, a filter may be further disposed between the image sensor 120 and the plurality of lenses 130. [ The filter may be an IR (InfraRed) filter. The filter may comprise a film. The filter may block near-infrared light, for example, light having a wavelength of 700 nm to 1100 nm, from light incident into the camera module 100.

The filter and the plurality of lenses 130 are built in a lens holder (not shown) and can be supported.

The OIS device 140 includes a magnet 142 disposed around the lens, a coil 144 disposed away from the magnet, and a drive IC 146 for applying a voltage to the coil.

When a plurality of lenses 130 are stacked in the Z-axis direction, one magnet-coil pair may be arranged in the X-axis direction and another magnet-coil pair may be arranged in the Y-axis direction.

When the drive IC 146 applies a voltage to the coil 144, a magnetic field can be formed around the magnet 142 and the coil 144 due to the current flowing through the coil 144. [ Accordingly, it is possible to correct a camera-shake or the like by moving the plurality of lenses 130. [

Here, the coil 144 may be a voice coil motor (VCM) coil, and the driving IC 146 may apply a voltage to the coil 144 by a PWM (Pulse Width Modulation) method.

Although not shown, an OIS device 140 is also embedded in a lens holder together with a filter and a plurality of lenses 130, and can be supported by a lens holder.

The camera module according to the embodiment of the present invention can be embedded in a portable terminal such as a smart phone, a tablet PC, a laptop computer, a PDA, or the like.

Fig. 2 shows an example of an OIS device, and Fig. 3 shows a voltage applied to the coil in accordance with the drive IC output of Fig.

2, the OIS device 200 includes magnets 210 and 212 disposed around the lens L, coils 220 and 222 spaced apart from the magnets 210 and 212, And a driving IC 230 electrically connected to both terminals of the coils 220 and 222 to apply a voltage to the coils 220 and 222.

The magnets 210 and the coils 220 are arranged in the X axis direction and the magnets 212 and the coils 222 are arranged in the Y axis direction.

Both terminals T1 and T2 of the coil 220 are connected to the output terminal X + and the output terminal X-, and both terminals T3 and T4 of the coil 222 are connected to the output terminal Y + -).

The PWM signals output from the respective output stages (X +, X-, Y +, Y-) can be applied to the coils 220 and 222.

When the VDD of each output stage (X +, X-, Y +, Y-) is +2.8 V, a drive signal of 0 to +2.8 V can be output from the output stage (X +, Y +) depending on the input voltage of each transistor , And a drive signal of -2.8 to 0 V can be output from the output stage (X-, Y-).

However, the voltage applied to the driving IC of FIG. 2 and the coil of FIG. 3 is merely an example, and may be designed in various forms.

4 shows an example of an image sensor included in the camera module, FIG. 5 shows an ADC (Analog to Digital Converter) included in the image sensor of FIG. 4, Describes how to detect brightness.

4, the image sensor 400 includes a plurality of pixels, and includes photo detectors (photo detectors, 400-11, ..., 400-NM) included in each pixel, A vertical scan circuit 410, a horizontal scan circuit 420 connected to a vertical line of pixels, a correlated double sampling (CDS) 430-1 connected to each column of pixels. ., 430-M) and ADCs (Analog to Digital Converters, 440-1, ..., 440-M) connected to each CDS.

When light is incident on the photodetector circuits 400-11 to 400-NM, an electron-hole pair (EHP) can be formed. The thus formed analog signal can be transmitted to the output terminal in accordance with the gate bias of the transistor included in the photodetector circuits 400-11, ..., and 400-NM. The transmitted analog signal is converted into a digital signal through the ADC and can be implemented as a pixel.

4 to 6, the ADC 440-1 includes an amplifier 442-1, a comparator 444-1, and a digital memory 446-1.

An analog signal output through the optical detection circuits 400-11, ..., 400-N1 in the first column is input to the ADC 440-1. An analog signal output through the optical detection circuits 400-11, ..., 400-N1 in the first column may be represented by a pixel signal (V _SF ) in FIG.

The input pixel signal is amplified by the amplifier 442-1 and then compared with a reference signal (V _RAMP ) in the comparator 444-1. Here, the reference signal may be generated by a single slope ramp generator. The reference signal generated by the single slope ramp generator may include a first count period (Down-count period) and a second count period (Up-count period). Reset ramp counting may be performed in the first count interval and signal ramp counting may be performed in the second count interval. Digital memory (446-1) is a counter output (Output Counter) using a counter clock (Clock Counter, Ø _TCK) and comparator output (Comparator output, V _COUT) of the first counting interval and a second interval count of the reference signal Can be generated. This counter output can be used as a gray value for the brightness of the light. In this specification, the first count interval and the second count interval may be mixed with the ADC readout interval.

On the other hand, as described in Fig. 1, the driving IC (hereinafter referred to as driving IC) of the OIS device and the image sensor are located adjacent to each other. Accordingly, a signal output from the driving IC causes a magnetic flux in the periphery of the image sensor, and may affect the operation of the image sensor. In particular, the PWM signal output from the driving IC of the OIS device during the first count interval and the second count interval of the reference signal may cause noise on the image.

7 specifically shows the influence of the PWM signal outputted from the driving IC of the OIS device on the operation of the image sensor.

Referring to FIG. 7, when the PWM signal of the driving IC rises (P1) or falls (P2) in the first count period or the second count period of the counter clock (Counter Clock, _TCK ) , It may cause noise on the image.

According to the embodiment of the present invention, the ADC reading period of the image sensor, for example, the count period of the reference signal and the raising edge or falling edge of the PWM signal are prevented from overlapping or synchronized with each other .

8 shows an example in which the ADC readout period and the rising edge or the falling edge of the PWM signal do not overlap. That is, the PWM signal can be maintained in the HIGH, H state or in the LOW, L state within the ADC readout period.

9 shows an example in which the ADC readout period and the PWM rising edge or falling edge are synchronized. That is, the rise of the counter clock and the PWM rise simultaneously in the ADC readout period may occur simultaneously, or the falling of the counter clock and the PWM fall in the ADC readout period may occur at the same time. Here, the rising edge means a time point when the pulse of the PWM signal is switched from the LOW state to the HIGH state, and the falling edge means that the pulse of the PWM signal is switched from the HIGH state to the LOW state, .

10 shows an image sensor and a driving IC according to an embodiment of the present invention. The same contents as those of FIG. 1 will be omitted.

10, the image sensor 1000 and the driving IC 1010 are electrically connected, and the image sensor 1000 transmits the synchronizing signal of the image sensor 1000 to the driving IC 1010. To this end, the image sensor 1000 includes at least one first pin 1002, and the driving IC 1010) may include at least one second pin 1012. [ The synchronization signal may be output from the first pin 1002 and input to the second pin 1012.

The driving IC 1010 outputs a PWM (Pulse Width Modulation) signal to both ends of the coil based on the synchronization signal received from the image sensor 1000. [

For example, as illustrated in FIG. 8, the driving IC may be configured such that the ADC reading period of the image sensor, for example, the sampling period of the reference signal, and the rising or falling edge of the PWM signal are overlapped The PWM signal can be output.

Alternatively, as illustrated in FIG. 9, the driving IC may output a PWM signal such that at least one of a rising edge and a falling edge of the PWM signal is synchronized with the synchronous signal. That is, the PWM signal can be outputted so that the rising of the PWM signal and the rising of the synchronous signal occur simultaneously, or the falling of the PWM signal and the falling of the synchronous signal occur simultaneously.

At this time, the synchronous signal transmitted from the image sensor 1000 to the driving IC 1010 is at least one of the horizontal synchronizing signal Hsync, the vertical synchronizing signal Vsync, the pixel clock signal, the ADC synchronizing signal, It can be one.

Information on the relationship between the synchronizing signal and the ADC reading interval is predefined in the driving IC 1010 and can be stored in advance in the OIS device. Information on the relationship between the synchronization signal and the ADC readout interval can be stored in a table form. Thus, after extracting the information on the ADC readout period from the synchronization signal, the PWM signal can be output using the extracted information.

11 to 12 show an example in which the driving IC outputs the PWM signal using the synchronous signal received from the image sensor according to an embodiment of the present invention.

Referring to Figs. 11 to 12, the driving IC receives the horizontal synchronizing signal Hsync and the vertical synchronizing signal Vsync from the image sensor, and extracts the ADC reading period therefrom.

It is also possible to output the ADC readout period so that the rising edge and the falling edge of the PWM signal do not overlap with each other, or the rising time point or the falling time point of the counter clock in the ADC readout period may coincide with the rising time point or the falling time point of the pulse of the PWM signal.

Although not shown, the driving IC can directly control the output of the PWM signal by using the synchronizing signal without extracting the relationship between the synchronizing signal and the ADC reading interval. For example, if the sync signal is Hsync, the interval in which Hsync is low can coincide with the ADC read interval. By using this, it is possible to control the PWM signal to be outputted in a period in which Hsync is in a high state.

Further, although not shown, the image sensor may also transmit information on the ADC read period, for example, a counter clock of the reference signal directly to the driving IC. In this case, the driving IC does not need to extract the relationship between the synchronizing signal and the ADC reading period.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

100: Camera module
110: PCB
120: Image sensor
130: lens
140: OIS device
142: Magnet
144: Coil
146: Driving IC

Claims (11)

A magnet disposed around the lens,
A coil spaced apart from the magnet and including a first terminal and a second terminal,
A pulse width modulation (PWM) circuit electrically connected to the first terminal and the second terminal and electrically connected to the image sensor, the first terminal and the second terminal being based on a synchronization signal received from the image sensor, A driving IC for outputting a signal
An optical image stabilization (OIS) device. The method according to claim 1,
Wherein at least one of a rising edge and a falling edge of the PWM signal does not overlap an ADC readout period of the image sensor. The method according to claim 1,
Wherein at least one of a rising edge and a falling edge of the PWM signal is synchronized with the synchronization signal. The method of claim 3,
At least one of a rising edge of the PWM signal and at least one of rising edges of the synchronization signal coincide with each other or at least one of falling edges of the PWM signal and a falling edge of the synchronization signal coincides with each other. The method according to claim 1,
Wherein the synchronization signal comprises at least one of a horizontal synchronization signal (Hsync), a vertical synchronization signal (Vsync), a pixel clock signal, an ADC synchronization signal, and an image input clock signal of the image sensor. Printed circuit board,
An image sensor electrically connected to the printed circuit board,
A plurality of lenses formed on the image sensor and arranged in sequence, and
An optical image stabilization (OIS) device,
The OIS device
A magnet disposed around the lens,
A coil spaced apart from the magnet and including a first terminal and a second terminal,
A first terminal and a second terminal, the first terminal being electrically connected to the first terminal and the second terminal being electrically connected to the first terminal; ) Driving IC for outputting a signal
. The method according to claim 6,
The plurality of lenses are arranged in a first axial direction,
The OIS device
A first magnet and a first coil arranged in a second axis direction perpendicular to the first axis direction,
A second magnet disposed in a third axial direction perpendicular to the first axial direction and the second axial direction,
. The method according to claim 6,
The image sensor comprising at least one first pin,
Wherein the OIS device comprises at least one second pin and wherein the image sensor and the OIS device are electrically connected via the first pin and the second pin. 9. The method of claim 8,
Wherein the synchronization signal is output from the first pin and input to the second pin. A magnet disposed around the lens,
A coil spaced apart from the magnet and including a first terminal and a second terminal,
And a driving IC which is electrically connected to the first terminal and the second terminal and outputs a PWM (Pulse Width Modulation) signal to the first terminal and the second terminal,
/ RTI >
The raising edge or falling edge of the PWM signal does not overlap the analog to digital converter (ADC) readout period of the image sensor. 11. The method of claim 10,
Wherein the ADC read interval comprises a sampling interval of a reference signal for an ADC of the image sensor.

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