KR100966340B1 - A solenoid type mechanical shutter driving circuit for mobile use - Google Patents

Abstract

The present invention relates to a solenoid type mechanical shutter driving circuit for mobile devices, and more particularly, by using two channels of a driver IC and taking a structure in which two solenoids are separated, the mounting space is limited, thereby providing sufficient torque. The present invention relates to a solenoid type mecha shutter driving circuit for mobiles that achieves a fast shutter speed of about 1/1000 second under difficult mobile environments.

To this end, the mobile solenoid type mechanical shutter drive circuit according to the present invention includes a first solenoid and a second solenoid for providing a drive torque to the magnet; A magnet located between the first solenoid and the second solenoid; And a driver IC receiving a voltage to supply current to the first solenoid and the second solenoid, the driver IC including a plurality of channels. Wherein the first solenoid is connected to a first channel of a plurality of channels of the driver IC, the second solenoid is connected to a second channel of a plurality of channels of the driver IC, and the first solenoid And the second solenoid is spaced apart from each other.

 Mobile, Solenoid, Mecha Shutter, Drive Circuit, Shutter Speed

Description

Solenoid type mechanical shutter driving circuit for mobiles {A solenoid type mechanical shutter driving circuit for mobile use}

The present invention relates to a solenoid type mechanical shutter driving circuit for mobile devices, and more particularly, by using two channels of a driver IC and taking a structure in which two solenoids are separated, the mounting space is limited, thereby providing sufficient torque. The present invention relates to a solenoid type mecha shutter driving circuit for mobiles that achieves a fast shutter speed of about 1/1000 second under difficult mobile environments.

In general, mobile phones are becoming smaller and smaller due to high sensitivity and light weight of electronic components, and the functions of mobile phones are gradually diversified according to various needs of consumers. Camera phones that incorporate a camera function of taking and storing images and transmitting them to the other party are commercially available.

On the other hand, as the number of pixels in the camera phone increases, image distortion that may occur when a moving subject is photographed using an electric shutter in the CMOS sensor is prevented, and a mobile camera is used to capture a moving subject in low light. Mecha-shutters are being installed. On the other hand, a lens having a large aperture or a small F value is used to improve low light characteristics.

However, when a lens having a large aperture is used to improve low light characteristics, the mounting space of the mechanical shutter is insufficient due to the characteristics of a mobile camera having a limited mounting space, unlike a digital camera having a relatively large volume. In other words, the larger the opening, the larger the stroke that the shutter opens or closes, but the mobile camera lacks a mounting space for the actuator, which makes it difficult to secure a torque for a sufficient shutter speed. .

In addition, since the voltage that can be used for mobile is usually limited to 3.3V, it is also difficult to raise the voltage indefinitely to secure sufficient torque.

As a conventional circuit structure for driving a solenoid type mechanical shutter for mobile, there are a structure using a step motor and a structure using a solenoid method. First of all, the step motor structure has the advantage of being able to adjust the aperture step by step, but has the disadvantage of being large and heavy. In particular, the step motor method has a problem in that the weight reduction problem must be solved in order to be used in a mobile environment as it is coupled to the lens group.

As another structure, the structure using the solenoid method has an advantage that the size of the driving circuit is small and suitable for mobiles with small space, but it is difficult to achieve a sufficient shutter speed due to the difficulty of adjusting the iris step by step and the small driving torque.

In an effort to improve drive torque in mobile environments where it is difficult to use large solenoids or large magnets to obtain sufficient torque due to limited space, the use of two solenoids in the mecha shutter drive circuit has been devised.

1 schematically illustrates a conventional solenoid type mechanical shutter driving circuit 10. FIG. 1 illustrates a method of connecting one solenoid 13 in series using one channel (not shown) of the driver IC 11 as one of such conventional structures. The solenoid here refers to winding the coil several times on a metal rod.

The principle that the mechanical shutter 12 operates by the present method is as follows. Around the circular magnet 14, the metal rod 15 in which the solenoid 13 is wound is located in both sides. At this time, the reason for using two solenoids 13 is to improve the drive torque. When the current flows in the solenoid 13, the magnet 14 rotates about the central axis by electromagnetic force, and the shutter is opened and closed by moving a blade (not shown) by a mechanism (not shown) connected thereto. will be.

However, a problem with this method is that the shutter is not opened or closed under the condition that the voltage applied to the driver IC is 5V or less.

Another conventional structure using a solenoid scheme designed to operate at voltages lower than 5V is shown in FIG. 2 schematically shows a solenoid type mechanical shutter driving circuit 20. 2 is the same as the structure of FIG. 1 in that one channel of the driver IC 11 is used, except that two solenoids 13 are connected in parallel.

However, this method also does not normally open and close the shutter when the voltage applied to the driver IC is less than 4V. That is, the conventional solenoid type mechanical shutter driving circuit using only one channel of the driver IC cannot expect smooth shutter opening and closing operation with a driving voltage of about 4V or less. Therefore, there is a problem to apply to a mobile camera module commercially available under a drive voltage of about 3.3V.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and by using two channels of the driver IC, and taking a structure in which two solenoids are separated, providing sufficient torque in a limited mounting space It is an object to provide a driving circuit that produces a fast shutter speed of 1/1000 second.

In addition, an object of the present invention is to provide a drive circuit that can adjust the current consumption per channel of the driver IC to 200 ~ 240mA while using a drive voltage of about 3.3V for the shutter speed as described above.

As a technical configuration for achieving the above object, a mobile solenoid type mechanical shutter driving circuit according to the present invention includes: a first solenoid and a second solenoid for providing a driving torque to a magnet; A magnet located between the first solenoid and the second solenoid; And a driver IC receiving a voltage to supply current to the first solenoid and the second solenoid, the driver IC including a plurality of channels, wherein the first solenoid is a first channel of the plurality of channels of the driver IC. The second solenoid is connected to a second channel of the plurality of channels of the driver IC, wherein the first solenoid and the second solenoid are separated from each other.

Preferably, the first channel includes a first output terminal and a second output terminal, the first output terminal is connected to one end of the first solenoid, and the second output terminal is the other end of the first solenoid. The second channel includes a third output terminal and a fourth output terminal, the third output terminal is connected to one end of the second solenoid, and the fourth output terminal is the other end of the second solenoid. Can be connected to.

More preferably, the first channel and the second channel may be driven in a constant current manner.

More preferably, a voltage of 3.3V or less may be applied to the driver IC for the operation of the mobile solenoid type mechanical shutter driving circuit.

More preferably, when the mobile solenoid type mechanical shutter driving circuit operates, current consumption of the first channel and the second channel may be 200 mA or more and 240 mA or less, respectively.

The mobile solenoid type mechanical shutter driving circuit according to the present invention uses two channels of a driver IC and takes a configuration in which two solenoids are separated, and under a condition in which mounting space is limited and sufficient torque is difficult to obtain. It provides a solenoid type mecha shutter driving circuit for mobiles with a fast shutter speed of 1000 seconds. In addition, the present invention provides a drive circuit that can adjust the current consumption per channel of the driver IC to 200 ~ 240mA while using a drive voltage of about 3.3V for the fast shutter speed as described above provides a solenoid type mechanical shutter drive circuit for mobiles do.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 shows a solenoid type mechanical shutter driving circuit 30 for mobile according to the present invention.

As shown in FIG. 3, the mobile solenoid type mechanical shutter driving circuit according to the present invention includes a driver IC 31, a first solenoid 38, a second solenoid 39, and a magnet 40.

The driver IC 31 has a plurality of channels including the first channel 32 and the second channel 33. Unlike the conventional use of only one channel of the driver IC, the mobile solenoid type mechanical shutter driving circuit according to the present invention has two channels among the plurality of channels of the driver IC 31, that is, the first channel 32 and the first channel. Two channels 33 are used. In FIG. 3, the illustration of the other channels except for the first channel 32 and the second channel 33 is omitted.

At this time, if two channels are configured using one channel in two driver ICs, there is a problem in that the uniformity of the operation of the shutter is not guaranteed due to the timing difference. It uses one driver IC that supports constant current driving.

The first channel 32 and the second channel 33 each have two output terminals. That is, the first channel has a first output terminal 34 and a second output terminal 35, and the second channel has a third output terminal 36 and a fourth output terminal 37.

The first channel 32 and the second channel 33 are respectively connected to two different solenoids, namely, the first solenoid 38 and the second solenoid 39. More specifically, the first output terminal 34 and the second output terminal 35 are connected to one end and the other end of the first solenoid 38, respectively, and the third output terminal 36 and the fourth end of the first output terminal 34. The output terminal 37 is connected to one end and the other end of the second solenoid 39, respectively.

In addition, the first solenoid 38 and the second solenoid 39 are not electrically connected but are separated from each other.

The magnet 40 is located between the first solenoid 38 and the second solenoid 39 and is connected to a mechanism (not shown) connected to a blade for opening and closing the shutter.

The first solenoid 38 and the second solenoid 39 serve to provide a driving torque to the magnet 40, and the driver IC 31 receives a voltage to the first solenoid 38 and the The current is supplied to the second solenoid 39.

When the current flows in the first solenoid 38 and the second solenoid 39, the magnet 40 is rotated about the central axis by the electromagnetic force generated by it, and the mechanism connected to the magnet (not shown) The shutter is opened and closed by moving the blade (not shown).

Mobile solenoid type mechanical shutter driving circuit according to the present invention produces a fast shutter speed of about 1/1000 seconds in a low voltage environment. Hereinafter, the operation of the mobile solenoid type mechanical shutter driving circuit according to the exemplary embodiment of FIG. 3 and the operation of the conventional mechanical shutter driving circuit of FIG. 2 will be described.

Example

The mobile solenoid type mechanical shutter driving circuit 30 according to the present invention includes a driver IC 31, a first solenoid 38, a second solenoid 39, and a magnet 40. The driver IC 31 includes a first channel 32 and a second channel 33, the first channel 32 including a first output terminal 34 and a second output terminal 35. The two channels 33 include a third output terminal 36 and a fourth output terminal 37. The first output terminal 34 is connected to one end of the first solenoid 38, and the second output terminal 35 is connected to the other end of the first solenoid 38. In addition, the third output terminal 36 is connected to one end of the second solenoid 39, and the fourth output terminal 37 is connected to the other end of the second solenoid 39. At this time, the first solenoid 38 and the second solenoid 39 are separated from each other.

 By using the method shown in FIG. 4A, the shutter opening speed according to the operation of the mobile solenoid type mechanical shutter driving circuit 30 of the present invention is measured. The mobile solenoid type mechanical shutter driving circuit 30 is connected to the shutter 43 to operate the shutter 43 in the above-described manner, which is not shown in FIG. 4A. As the shutter 43 is opened, the exposed light is converted into a light receiving signal by a photo diode 41, and the converted signal is measured by the oscilloscope 42.

In one embodiment of the mobile solenoid type mechanical shutter driving circuit 30 of the present invention, a 3.3V voltage is applied to the driver IC, and the shutter driving current of the solenoid having a resistance value of 11.1 ohm and 11.5 ohm in two cases ( 44 and 46 and received signals 45 and 47, respectively.

This result is shown in FIG. 4B and FIG. 4C. The horizontal axis represents time (ms), the vertical axis represents current intensity (mA), and the scale is adjusted so that the shutter drive currents 44 and 46 and the light receiving signals 45 and 47 can be easily compared.

Tb in FIGS. 4B and 4C is a value representing a delay until the shutter is operated, and has a value different according to the condition of the driver IC. Since the offset is adjusted for each shutter product, it is not important to change the T1 value according to the driver IC condition. However, repeatability should be observed when the same shutter is operated several times under the same driver IC condition.

T2 is the time when the shutter is closed and is the difference between the time point of 90% of the initial light amount and the time point of 10% of the initial light amount. The smaller the value of T2, the faster the shutter speed.

As shown in FIG. 4B, when the resistance of the solenoid is 11.1 ohm, T2 is 1.0 ms, and the shutter driving current, that is, the current consumption in the channel is 240 mA. In addition, as shown in FIG. 4C, when the resistance of the solenoid is 11.5 ohm, T2 is 1.1 ms and the current consumption in the channel is 230 mA.

That is, the voltage used for mobile is usually 3.3V or less, the mobile solenoid type mechanical shutter drive circuit 30 of the present invention according to the configuration of Figure 3 satisfies this condition and consumes each channel It can be seen that the shutter speed is about 1/1000 second while setting the current to about 200 mA to 240 mA.

Comparative example

The solenoid type mechanical shutter driving circuit 20 shown in FIG. 2 includes a driver IC 11, two solenoids 13 and a magnet 14 connected in parallel, and one channel of the driver IC 11. It characterized in that to use.

The solenoid type mechanical shutter drive circuit 20 also measures the shutter speed in the same manner as in the above-described embodiment, and shows the result using T1 and T2.

The solenoid type mechanical shutter driving circuit 20 according to the structure of FIG. 2 operates normally when 5V is applied to the driver IC. However, this is a voltage condition that cannot be used in mobile environments.

Table 1 below shows the comparative example 1 to the comparative example 9 applying 3.8V to the driver IC in the solenoid type mechanical shutter driving circuit according to the structure of FIG. 2 and varying the solenoid resistance values little by little, and T1 and 3 times for each comparative example. It is data measured T2.

TABLE 1

At this time, the case where T2 is 0, that is, the shutter does not operate appears. Furthermore, the second data of Comparative Example 2 and the third data of Comparative Example 3 show that the T1 value has a severe deviation even when the solenoid resistance values are the same. That is, even though the same shutter is driven in the same environment, there is a problem that the T1 value is not constant.

Therefore, in the driving circuit shown in FIG. 2, the shutter operates normally when 5V is applied to the driver IC. However, when 3.8V is applied, the shutter does not operate 3 times (Comparative Examples 6, 7, and 9). Can be.

As described above, the conventional comparative example operates normally only when a high voltage of 5V is applied, and the shutter does not operate normally even when only 3.8V is applied. In contrast, in the exemplary embodiment of the present invention, a fast shutter speed of about 1/1000 second may be obtained by applying a 3.3V voltage suitable for a mobile environment. In other words, it is not necessary to use a high voltage of 4 to 5V to obtain a fast shutter speed, and the power consumption per channel can be adjusted to 200 to 240mA, thereby reducing power consumption.

1 is a schematic configuration diagram of a conventional mechanical shutter driving circuit using a solenoid method.

2 is a schematic configuration diagram of another conventional mechanical shutter driving circuit using a solenoid method.

3 is a schematic configuration diagram of a solenoid type mechanical shutter driving circuit for mobile according to the present invention.

4A is a schematic block diagram of a circuit for measuring a shutter speed of a mechanical shutter driving circuit according to the present invention and the conventional configuration.

4B and 4C are graphs illustrating shutter speeds of a mechanical shutter driving circuit according to an exemplary embodiment of the present invention.

[Description of Major Symbols in Drawing]

10: mechanical shutter drive circuit 11: driver IC

12: mecha shutter 13: solenoid

14: magnet 20: mechanical shutter drive circuit

30: Solenoid type mechanical shutter drive circuit for mobile

31: driver IC 32: first channel

33: second channel 34: first output terminal

35: second output terminal 36: third output terminal

37: fourth output terminal 38: first solenoid

39: second solenoid 40: magnet

41: photodiode 42: oscilloscope

43: shutter 44: shutter drive current

45: light receiving signal 46: shutter drive current

47: Received signal

Claims (5)

In the solenoid type mechanical shutter drive circuit for mobiles, The mobile solenoid type mechanical shutter drive circuit is: A first solenoid and a second solenoid for providing a drive torque to the magnet; A magnet located between the first solenoid and the second solenoid; And A driver IC receiving a voltage to supply current to the first solenoid and the second solenoid, the driver IC including a plurality of channels; Including, The first solenoid is connected to a first channel of a plurality of channels of the driver IC, the second solenoid is connected to a second channel of a plurality of channels of the driver IC, The solenoid type mechanical shutter driving circuit for mobiles, wherein the first solenoid and the second solenoid are separated from each other. The method of claim 1, The first channel includes a first output terminal and a second output terminal, the first output terminal is connected to one end of the first solenoid, the second output terminal is connected to the other end of the first solenoid, The second channel includes a third output terminal and a fourth output terminal, wherein the third output terminal is connected to one end of the second solenoid, and the fourth output terminal is connected to the other end of the second solenoid. Mobile solenoid type mechanical shutter drive circuit characterized by the above-mentioned. The method according to claim 1 or 2, And the first channel and the second channel are driven in a constant current manner. The method according to claim 1 or 2, And a voltage of 3.3V or less is applied to the driver IC for the operation of the mobile solenoid type mechanical shutter driving circuit. The method according to claim 1 or 2, When the mobile solenoid type mechanical shutter drive circuit is operated, the current consumption of the first channel and the current consumption of the second channel is a mobile solenoid type mechanical shutter drive circuit, characterized in that 200mA to 240mA.

Images