CN100529944C

CN100529944C - Auto-focusing system

Info

Publication number: CN100529944C
Application number: CNB2004100774795A
Authority: CN
Inventors: 李俊佑
Original assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2004-12-10
Filing date: 2004-12-10
Publication date: 2009-08-19
Anticipated expiration: 2024-12-10
Also published as: CN1786807A

Abstract

The invention relates to an automatically focusing system that includes set of lens, beam splitter prism, sensor, secondary light source, icon board, driver and corresponding circuit. The beam splitter prism is set between the set of lens and the sensor. The corresponding circuit controls the assistant light from the secondary light source passing through the iron board to form image beam and incident to the beam splitter prism and reflecting to set of lens, and controls the driver to drive the set of lens. The invention is simple structure, and low cost.

Description

Autofocus system

[technical field]

The invention relates to a kind of autofocus system, particularly about a kind of autofocus system that is used for digital camera.

[background technology]

Existing automatic focusing can be divided into active automatic focusing and the automatic focusing of passive type two classes.Active automatic focusing: by camera emission infrared ray or ultrasound wave to subject, inductor is according to the infrared ray or the ultrasound wave that reflect, calculating by DSP in the camera (Digital Signal Processor), draw the distance of camera and subject, control focusing driver moving lens reaches accurate focusing then.But, distance, smooth surface big and have can absorbing light and the object focusing difficulty on the surface of ripple for brightness.Passive type is focused automatically: camera is accepted to come judging distance to focus automatically from the reflective of subject itself.The advantage of this focusing mode is: do not need to launch light or ripple, cut down the consumption of energy, can accurately focus under the good situation of light simultaneously; Shortcoming is: focusing difficulty when light luminance and contrast deficiency.In order to overcome above-mentioned shortcoming, the automatic focusing of design auxiliary lamp (Auto Focus AidLights) on most cameras, the emission light beam illuminates subject helps focusing, thereby makes the automatic focusing of passive type utilize the mode of similar active automatic focusing to overcome because the focusing difficulties that deficiency caused such as light luminance and contrasts.

United States Patent (USP) the 4th, 843, a kind of automatic focusing detection system is disclosed for No. 415, it is provided with the fill-in light emitter window on camera, this emitter window is positioned at outside the camera lens, in emitter window, be equiped with LED (Low EmittingDiode) light source, icon board, attachment lens, when the contrast of taking thing is not enough, the fill-in light that led light source sends is taken on the thing through forming scored fill-in light after the icon board and being incident upon, enter from the fill-in light of taking the thing reflected back from camera lens in the camera body by CCD (Charge Coupled Device) sensor sensing, and handle back control focusing operation by interlock circuit.

Chinese patent application discloses a kind of camera No. 03155964.6, it has and the similar structure of above-mentioned United States Patent (USP), it not only will assist emitter window to be arranged on outside the camera lens, and the sensor that will detect fill-in light also is arranged on outside the camera lens, so just make fill-in light emission and accept all not pass through camera lens.

Yet, use auxiliary emitter window to form relatively independent auxiliary focusing system and increased assembly, can not make full use of original camera lens, cause the raising of cost, simultaneously, because auxiliary emitter window is located at a side of camera, thereby can cause maloperation to the part of the body cavity above the diaphragm housing the heart and lungs not when hand blocks emitter window accidentally when being in one's hands camera.

In view of above-mentioned deficiency, be necessary in fact to provide a kind of simple in structure, cost is lower, misuse rate is low autofocus system.

[summary of the invention]

Technical matters to be solved by this invention provides a kind of simple in structure, cost is lower, misuse rate is low autofocus system.

The invention provides a kind of autofocus system, comprise lens set, Amici prism, sensor, secondary light source, icon board, driver and interlock circuit, this Amici prism is located between lens set and the sensor, this secondary light source is subjected to this interlock circuit control to send fill-in light and reflexes to lens set through this icon board to form patterned light beam and to be incident to this Amici prism, and this driver is subjected to this interlock circuit control to drive lens set.

Compared with prior art, the present invention's autofocus system is by assemblies such as shared lens set and image sensors, reduce assembly quantity, reduced cost, and owing on the camera body fill-in light emitter window is set no longer, reduce because finger blocks the probability of the maloperation that emitter window causes.

[description of drawings]

Fig. 1 is the synoptic diagram of first embodiment of the invention.

Fig. 2 is the synoptic diagram of second embodiment of the invention.

[embodiment]

See also Fig. 1, the present invention's autofocus system 100 comprises lens set 1, Amici prism 2, image sensor 3, A/D change-over circuit 4, signal processing circuit 5, detecting circuit 6, CPU7, secondary light source 8, icon board 9 and driver 10.

Amici prism 2 is arranged between lens set 1 and the

image sensor

3,20 atomizings of one side surface and blacking are handled, and are coated with infrared cut of light film (IR-cut filter) to prevent the adverse effect of infrared light to image sensor 3 with image sensor 3 relative side surfaces 22.

Image sensor 3 can be CMOS (Complementary Metal-Oxide Semiconductor) or CCD image sensor.

A/D change-over circuit 4 is also sampled and is kept and gain control circuit (S/H﹠amp; AGC), the image signal transformation of its shooting thing that self imaging sensor 3 can be imported into becomes digital signal.

Signal processing circuit 5 can be carried out input and processing such as color, brightness.

The promptly automatic focusing detecting circuit of detecting circuit 6, it can be processed into contrasting signal with luminance signal.

CPU7 is a microcontroller circuit, and it is by each circuit signal control secondary light source 8 and driver 10.

Secondary light source 8 (as LD (Laser Diode) or LED) be arranged on Amici prism 2 one sides, but its visible emitting.

Icon board 9 is arranged between secondary light source 8 and the Amici prism 2, also can be formed directly on the Amici prism 2 with the surface of secondary light source 8 relative sides on.Be formed with the pattern of particular space frequency (specified spatial frequency) on the icon board 9, can be by etching tiny striped formation on the glass surface or on the light shield (mask).

Driver 10 connects lens set 1 and CPU7, and it can drive lens set 1 and move with the operation of focusing along its optical axis under the control of CPU7.

During work, be incident to Amici prism 2 from the image light of taking thing (figure does not show) by lens set 1 after, be imaged on the image sensor 3, the image that image sensor 3 will be taken thing carries out opto-electronic conversion, converts digital signal to through A/D change-over circuit 4 again.The treated circuit 5 of digital signal converts color signal and luminance signal to, and is output to signal recording system (figure does not show).Simultaneously, this luminance signal converts the contrasting signal that automatic focusing needs to through detecting circuit 6, and exports the CPU7 interpretation that is used to control to.If contrasting signal be not maximum then CPU7 send a drive signal to driver 10 and move lens set 1 operation of focusing to drive driver 10, make contrasting signal reach maximum, thereby realize the automatic focusing of passive type, need not activate auxiliary focusing at this moment.If this moment, contrasting signal still can not reach maximum, then CPU7 sends a luminous signal so that secondary light source 8 sends fill-in light to icon board 9 to secondary light source 8.Fill-in light forms the fill-in light with pattern through icon board 9 backs, and this fill-in light is projected to Amici prism 2 back parts and is reflected to

lens set

1, and 20 backs, surface that another part is transmitted through Amici prism 2 are absorbed by the coating on it.Reflection is projected to the shooting thing to the fill-in light of lens set 1, and takes the light and dark candy strip of formation on the thing at this.The fill-in light of this band LO-pattern passes through lens set 1, Amici prism 2, image sensor 3 successively, input processing circuit 5, detecting circuit 6 are handled after A/D change-over circuit 4 converts digital signal to, again through the CPU7 interpretation, make this moment contrasting signal reach maximum, thereby realize active automatic focusing.

See also Fig. 2, it is the autofocus system 100 ' of the present invention's second embodiment.The autofocus system 100 of this autofocus system 100 ' and first embodiment is basic identical, and difference is:

Secondary light source 8 ' (as LD or LED) can be launched invisible light (is example with the infrared light).

Icon board 9 ' can be holographic eyeglass, and it can be arranged between secondary light source 8 ' and the Amici prism 2, also can be formed directly on the surface of Amici prism 2 and secondary light source a 8 ' relative side.

Set up image sensor 3 ' on one side at secondary light source 8 ', in order to sensing invisible light (is example with the infrared light).

During work, the autofocus system 100 of the course of work of this autofocus system 100 ' and first embodiment is basic identical, difference only is: the fill-in light that secondary light source 8 ' sends is through icon board 9 ', Amici prism 2, lens set 1 is projected to the fill-in light that is reflected behind the shooting thing and reflects in Amici prism 2 place's parts, the part transmission, the fill-in light of transmission is intercepted by the infrared ray cut film on the surface 22, be reflected onto icon board 9 ' fill-in light generation diffraction and behind the deviation certain angle, be projected to image sensor 3 ', process after this is described identical with first embodiment.

Claims

1. autofocus system, comprise a lens set, an Amici prism, at least one sensor, a secondary light source, an icon board, a driver and interlock circuit, this Amici prism is located between lens set and the sensor, this secondary light source be subjected to the control of this interlock circuit send fill-in light through this icon board to form patterned light beam, this driver is subjected to this interlock circuit control to drive lens set, and it is characterized in that: the fill-in light that this secondary light source sends is incident to this Amici prism back reflection to lens set through this icon board.

2. autofocus system according to claim 1 is characterized in that: this icon board is formed on the surface of a side relative with secondary light source on the Amici prism.

3. autofocus system according to claim 1 is characterized in that: this icon board and secondary light source are over against the phase the same side that is arranged at this Amici prism.

4. according to each described autofocus system in the claim 1 to 3, it is characterized in that: this icon board is formed on the side surface relative with this secondary light source on the Amici prism.

5. autofocus system according to claim 4 is characterized in that: handle to be absorbed into the fill-in light that is incident upon on this surface through atomizing and blacking from the opposing opposite side surface of the fill-in light plane of incidence that secondary light source sends on this Amici prism.

6. autofocus system according to claim 5 is characterized in that: the surface coating of the relative side with this sensor of this Amici prism is to end infrared light.

7. autofocus system according to claim 1 is characterized in that: this icon board is one the holographic eyeglass of deviation to take place at the fill-in light that light source sends when returning.

8. autofocus system according to claim 7 is characterized in that: this autofocus system further comprises the fill-in light of another sensor with the holographic eyeglass deviation of sensing, and transmits signals to this interlock circuit.