[background technology]
Along with the development of camera technique, the camera module is widely used in the camera head of various uses, and combining of camera module and various portable electron devices such as mobile phone, video camera, computer etc. obtains numerous consumers' favor especially.
The camera module generally includes a CD-ROM drive motor, at least one lens group and one and the photo-sensitive cell that is oppositely arranged of described lens group by drive motor.Lens group can comprise one or more eyeglasses, and described eyeglass and photo-sensitive cell are oppositely arranged, and the central point of photo-sensitive cell is positioned on the optical axis of these one or more eyeglasses.During focusing,, seek the focusing position (position of finding a view) of a tool optimum resolution with drive motor lens group and photo-sensitive cell relative displacement.During zoom, use the distance between the eyeglass in the CD-ROM drive motor moving lens group, thereby reach the purpose of zoom.
Step motor is to be used in the camera module to focus or the CD-ROM drive motor a kind of commonly used of zoom drive.Step motor generally includes a stator and a rotor, stator excitation rotor rotation, and the rotor driven eyeglass moves.The stroke that eyeglass and photo-sensitive cell relatively move is the focusing stroke of eyeglass and photo-sensitive cell, when focusing usually, step motor can drive eyeglass or photo-sensitive cell progressively steps to a final position from an initial position of the stroke of focusing, yet, step motor always needs to judge whether stepping forward again in the stepping process, can't learn accurately and timely whether eyeglass or photo-sensitive cell have arrived reference position or final position, this will expend the working time of focusing, and step motor also may have the problem of step-out in the moving process repeatedly at this.
In view of this, provide a kind of minimizing step motor step-out, and shorten the camera module of focusing working time and have a portable electron device of this camera module real for necessary.
[summary of the invention]
Below, will a kind of camera module be described with embodiment.
And a kind of portable electron device is described by embodiment.
A kind of camera module, it comprises lens group that a step motor, is driven by described step motor and one and the photo-sensitive cell that is oppositely arranged of lens group, wherein, described camera module also includes a light emitting devices, one is driven by described step motor, be used to reflect the light signal of described light emitting devices emission and light reflecting device with cyclical variation structure, and a light arrangement for detecting that is used for the light signal of the described light reflecting device reflection of sensing.
A kind of portable electron device, it comprises that an electronics and is arranged on the camera module in the electronics, described camera module comprises lens group that a step motor, is driven by described step motor and one and the photo-sensitive cell that is oppositely arranged of lens group, wherein, described camera module also includes a light emitting devices, one is driven by described step motor, be used to reflect the light signal of described light emitting devices emission and light reflecting device with cyclical variation structure, and a light arrangement for detecting that is used for the light signal of the described light reflecting device reflection of sensing.
Compared with prior art, described camera module utilizes light emitting devices emission light signal to the light reflecting device with cyclical variation structure that is driven by step motor, so the light arrangement for detecting can be detected step motor by the periodically variable light signal of sensor light reflection unit reflection and rotate the position that arrives, and the lens group that driven by step motor of detecting or the photo-sensitive cell position of moving arrival.By the light signal of described smooth arrangement for detecting sensing, step motor can accurately and timely be judged the lens group of its driving or reference position or the final position whether photo-sensitive cell arrives the focusing stroke, shortens the working time of focusing; Can know the position that changes focal length during zoom; And prevent the problem of step motor step-out.
[embodiment]
Below in conjunction with accompanying drawing camera module provided by the invention and portable electron device are described in further detail.
See also Fig. 1, the camera module 1 that the first embodiment of the present invention provides, it comprises lens group that a step motor 10, drives by described step motor 10 20, one and the photo-sensitive cell 30 that is oppositely arranged of described lens group 20, and a position detecting apparatus 40.
Described step motor 10 comprises a stator 11 and a rotor 12.Described stator 11 and rotor 12 are permeability magnetic material and make, and described stator 11 is a ring-type, is wound with coil 111 on the described stator 11, and described coil 111 is connected with a control device 110.Described rotor 12 is arranged in the described stator 11, and described rotor 12 also is a ring-type, is installed with an axle sleeve 121 on the described rotor 12, and described axle sleeve 121 inwalls offer screw thread.
Described lens group 20 comprises that a lens barrel 21 and is arranged on the eyeglass 22 in the lens barrel 21.Described lens group 20 is set in the described rotor 12, described lens barrel 21 outer walls offer screw thread, the outer wall thread of described lens barrel 21 matches with the inner thread of described axle sleeve 121, and when described axle sleeve 121 rotated, described lens barrel 21 and the eyeglass 22 that is arranged on wherein will move relative to photo-sensitive cell 30.The material of described eyeglass 22 can adopt plastics or glass, and described eyeglass 22 can adopt spheric glass or aspherical lens.
Described photo-sensitive cell 30 can be film, charge-coupled device (CCD) (Charge Coupled Device is called for short CCD) or complementary metal oxide semiconductor (CMOS) (ComplementaryMetal-Oxide-Semiconductor Transistor is called for short CMOS).Described photo-sensitive cell 30 can be arranged in the lens mount (figure does not show).In the present embodiment, described photo-sensitive cell 30 adopts CMOS, the mode of described CMOS encapsulation can adopt plastic leaded chip carrier encapsulation (Plastic Leaded ChipCarrier, abbreviation PLCC), ceramic lead chip carrier packages (Ceramic Leaded Chip Carrier, be called for short CLCC) or wafer-level packaging (Chip Scale Package is called for short CSP).
Described position detecting apparatus 40 comprises a light emitting devices 41, a light reflecting device 42 and a smooth arrangement for detecting 43.Described light emitting devices 41 and light arrangement for detecting 43 are arranged in the described stator 11 and with described lens barrel 21 outer walls and face mutually, and described light reflecting device 42 is arranged on described lens barrel 21 outer walls.Described light emitting devices 41 light sources can be LASER Light Source or light emitting diode (LED) light source.Described light reflecting device 42 is followed described lens barrel 21 and is moved together, described light reflecting device 42 can be a grating, described grating has along the chequered with black and white striped of lens barrel 21 axial distribution, and this chequered with black and white striped is the cyclical variation structure, can produce periodically variable reflected signal.Described smooth arrangement for detecting 43 comprises that one is used for light/power conversion circuit and that light signal converts electric signal to is used to count the digital processing circuit of electric signal.
Described light reflecting device 42 also is provided with an initial position 421 and a final position 422, the striped of described reference position 421 and final position 422 can be than periodically alternate striped be tight, thereby periodically variable reflected signal that can alternate striped with described periodicity produces with the reflected signal of its generation is distinguished and come.The reference position and the final position of the focusing stroke that the corresponding respectively described lens group 20 of described reference position 421 and final position 422 moves relative to photo-sensitive cell 30.The cyclical variation structure of described light reflecting device 42 moves axially time of replacement along described lens barrel can be identical with the time of described step motor 10 stepping certain angles, described light reflecting device 42 can also be set at identical with the time of described step motor 10 running integer circles from the traveling time that reference position 421 moves to final position 422, also be described light reflecting device 42 when moving to reference position 421 or final position 422, described step motor 10 also just running to its integer transposition put.
Certainly, the grating that above-mentioned light reflecting device 42 adopts can also be provided with the wire casing of a plurality of equidistant distributions, forms wire casing and projection cyclical variation structure spaced apart like this, and this cyclical variation structure can produce periodically variable reflected signal.
For another shown in Figure 2, described light reflecting device 42 also can adopt a raised structures in the distribution of lens barrel 21 outer wall axially spaced-aparts, this raised structures also can be one-body molded with lens barrel 21, and this raised structures is the cyclical variation structure, and it also will produce periodically variable reflected signal.
Certainly, other cyclical variation structure also can be applicable in the light reflecting device of the present invention, and its cyclical variation structure also will produce periodically variable reflected signal.
When focusing is used, coil 111 1 drive currents that the control device 110 of described step motor 10 is given on the described stator 11, described stator 11 just will produce an induced field, this induced field will encourage rotor 12 and the axle sleeve 121 that sets firmly thereon rotates, and described lens barrel 21 drives eyeglass 22 and moves relative to described photo-sensitive cell 30 along the optical axis of eyeglass 22 under described axle sleeve 121 effects.The light signal of light emitting devices 41 emissions of described position detecting apparatus 40 reflects through described light reflecting device 42, described smooth arrangement for detecting 43 just can sense the light signal of described light reflecting device 42 reflections, light/the power conversion circuit of described smooth arrangement for detecting 43 converts the light signal of sensing to electric signal, and can count described light reflecting device 42 periodically variable reflected signals, thereby know that step motor 10 rotates the position that arrives by digital processing circuit.
Described lens group 20 is described lens group 20 and can be divided into a plurality of exposure regions relative to the focusing stroke that described photo-sensitive cell 30 moves relative to the stroke that described photo-sensitive cell 30 moves, and can comprise a plurality of exposure stations again in each exposure region.Described step motor 10 drives lens group 20 to begin from reference position, step to each exposure region earlier, each exposure region exposes sampling respectively once, to obtain the resolution value of each exposure region, resolution value according to each exposure region is judged the optimum exposure district, step motor 10 drives lens group 20 self termination positions again and is back to this optimum exposure district then, the sampling that exposes respectively of each exposure station in this optimum exposure district, to seek the exposure station of best resolution value, this exposure station is the position of finally finding a view of lens group 20 and photo-sensitive cell 30.When step motor 10 drove lens group 20 and steps to the reference position of focusing stroke or final position, described light reflecting device 42 moved to its reference position 421 or final position 422 just, and described step motor 10 also is to have rotated the integer commentaries on classics just.So, according to the light/power conversion circuit of light arrangement for detecting 43 change periodically variable electric signal, step motor 10 can judge accurately and timely that lens group 20 arrives the reference position or the final position of focusing stroke, shorten the working time of focusing, and pass through the electric signal of the digital processing circuit count cycle property variation of light arrangement for detecting 43, just can know that step motor 10 rotates the position that arrives, also promptly know the distance of lens group 20 and described photo-sensitive cell 30, whether normal, prevent the problem of step motor 10 step-outs if so also playing 10 rotations of detecting step motor.
Certainly, in the foregoing description, in the described lens barrel 21 a plurality of eyeglasses 22 can be set, step motor 10 drives lens barrel 21 and these a plurality of eyeglasses 22 move relative to photo-sensitive cell 30 together.
Be understandable that in addition, described step motor 10 and position detecting apparatus 40 also can cooperate with the packaging system (figure does not show) of described photo-sensitive cell 30 and described photo-sensitive cell 30, described step motor 10 drives photo-sensitive cell 30 relative lens group 20 displacements, reach the purpose of focusing, described position detecting apparatus 40 detecting step motor 10 operational situations and photo-sensitive cell 30 moving states.
See also Fig. 3, camera module 2 partial cutaway schematic that provide for the second embodiment of the present invention.The difference of described second embodiment and described first embodiment is, described camera module 2 comprises two step motor 10a, the second lens group 20b that the first lens group 20a that 10b, is driven by described step motor 10a, is driven and is oppositely arranged with the described first lens group 20a by described step motor 10b, one photo-sensitive cell 30 that is oppositely arranged with the described first lens group 20a and the second lens group 20b, and two position detecting apparatus 40a, 40b.
Described step motor 10a drives the first lens group 20a, and described step motor 10b drives the second lens group 20b and moves relative to photo-sensitive cell 30 together, can reach the focusing purpose.Described step motor 10a drives the first lens group 20a and moves relative to described second lens group 20b and photo-sensitive cell 30, can reach the zoom purpose.Described position detecting apparatus 40a, 40b can detect described step motor 10a respectively, 10b rotates the position that arrives, the distance that the first lens group 20a and the second lens group 20b move relative to photo-sensitive cell 30 when also promptly knowing focusing, know the distance that the first lens group 20a moves during zoom, thereby can know the focal position of variation.
The present invention also provides a kind of portable electron device.
See also Fig. 4, the portable electron device 3 that embodiments of the invention provide comprises that an electronics 31 and is arranged on the camera module 32 in the electronics 31.Described portable electron device 3 can be portable type electronic products such as mobile phone, video camera or computer, and in the present embodiment, described portable electron device 3 is a mobile phone.
Described electronics 31 comprises a display screen 31a and some button 31b.Any one structure in the camera module that described camera module 32 can provide for previous embodiment.
Be understandable that, concerning one skilled in the relevant art, can make other various corresponding changes and distortion, and all these changes and distortion all should belong to the protection domain in claim of the present invention according to technical scheme of the present invention and technical conceive.