KR20060068611A - Image pickup device - Google Patents

Abstract

The present invention relates to an image pickup device used for a camera.

The image pickup device according to the present invention is assembled with the first lens and the second lens laminated on the first barrel, the third lens and the fourth lens assembled on the second barrel laminated, and the first lens The barrel assembly and the second lens barrel assembly are connected using threads formed in each other. Adjustment means for compensating for the cumulative tolerances in the assembly of the lens and the barrel are interposed on the surfaces of the first lens- barrel assembly and the second lens- barrel assembly that face each other. The adjusting means inserts a compression spring between opposing surfaces of each lens- barrel assembly and rotates the first lens- barrel assembly and the second lens- barrel assembly to adjust the distance between the second lens and the third lens. Is done. As a result, a high quality, high resolution and reliable image pickup device can be realized by compensating the influence of the accumulated tolerance.

Camera, Image pickup device, Image pickup lens, Image pickup unit

Description

Image pickup device {IMAGE PICKUP DEVICE}

1 is a side cross-sectional view of a conventional image pickup device.

Figure 2a is a side cross-sectional view of the image pickup device according to the present invention separated

Fig. 2B is a side cross-sectional view of the first lens member assembled in the image pickup device according to the present invention.

Fig. 2C is a side sectional view of the state in which the second lens member is assembled in the image pickup device according to the present invention.

Figure 3 is a side cross-sectional view of the first lens member and the second lens member assembled in the image pickup apparatus according to the present invention;

Fig. 4A is a side sectional view showing a state before adjustment of the image pickup device according to the present invention.

Fig. 4B is a side sectional view showing a state after adjustment of the image pickup device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: first barrel 110: first lens

120: second lens 200: second barrel

210: third lens 220: fourth lens

230: flare stop 300: spring

401: resolution chart 403, 404: transmission image

The present invention relates to an image pickup device applicable to a portable device.

Particularly, the present invention provides an image pickup lens capable of realizing a high resolution image, and includes a means for compensating by adjusting a tolerance generated in the lens and the barrel and a cumulative tolerance thereof, thereby preventing deterioration of the image quality of the lens due to tolerance accumulation. An image pickup device.

Camera apparatuses capable of photographing images are provided in portable devices including portable electronic devices such as mobile phones, PDAs, and portable computers. Cameras mounted on portable devices are inherently small and lightweight in terms of portability. The camera device includes a lens for forming an image from an object, an image sensor for recognizing an image formed from the lens, and an image processing unit for image processing an image obtained from the image sensor.

As described above, a camera mounted on a portable device has been advanced to enable high performance image acquisition while at the same time a requirement for compact and lightweight. In recent years, three or four lenses are used for the structure of the lens provided in the camera device. In general, four lens structures outperform three lens structures.

Since the three lens structures have higher performance compared to the single lens structure and the two lens structures, the first lens having positive refractive power, the second lens having negative refractive power, and are arranged in that order from the object side And a third lens having refractive power. This structure has been generally used as an image pickup lens of a small image pickup device. However, considering the degree of freedom of the structure, acquiring a high resolution image, and the like, the three lens structures are not suitable, and an image pickup device having four lens structures is required. Here, assuming that the image pickup lens has a lens structure of five or more pieces, a structure of five or more pieces is considered inappropriate because a large image pickup device is inevitably obtained.

Fig. 1 shows the structure of an image pickup apparatus using four conventional lenses.

An image sensor 10 for generating an electric image image signal in response to image light incident through the lens, and a base plate for retaining the image sensor, including a connection terminal for transmitting a signal from the image sensor 10. 20, a barrel 30 that functions as a lens barrel and includes an opening for incident light. In the figure, the left side is the object side and the right side is the image sensor side, and the dashed-dotted line represents the optical axis common to the lens.

The image pickup device includes an infrared cut filter 40 for preventing the incidence of infrared rays and a first lens L1, a stop S, and a second lens L2 arranged and supported by a barrel in order from the object side. And an image pickup lens having a third lens L3 and a fourth lens L4, thereby transmitting an image of the object through the respective lenses L1 to L4 and performing image formation in the image sensor 10. .

The barrel 30 fixes and holds all the lenses together with the base body 31 directly fixed to the base plate 20, the lens holder 32 for holding the fourth lens L4, and the lens holder 32. It includes a lens fixture 33. The lens fixture 33, the lens holder 32, and the base body 31 are almost cylindrically connected to each other completely, and are set so that the centerline is located on the same axis. In the barrel 30, a first light blocking mask 51 is arranged on the object-side barrel shell, and a second light blocking mask 52 is arranged between the second lens L2 and the third lens L3. The third light shielding mask 53 is arranged between the third lens L3 and the fourth lens L4. Each light shielding mask 51, 52, 53 has a circular opening and is positioned to block unnecessary light that does not form an image. That is, the interaction of the stop S and the light shielding masks 51, 52, 53 prevents light introduced from the object side from entering the area beyond the effective diameter of the lenses L1 to L4, and causes ghosting. Or flare is suppressed.

The base body 31 has the largest inner diameter and a lens holder 32 is located within the instrument body 31, with a female screw on the inner circumferential surface of the base body 31, and the lens holder 32 is external. It has a male thread on the circumferential surface. These screws are engaged with each other to connect the base body 31 and the lens holder 32. The lens holder 32 has a larger inner diameter than the lens fixture 33, and the lens fixture 33 is located in the lens holder 32. The lens holder 32 has a female screw on the inner circumferential surface, and the lens fixture 33 has a male screw on the outer circumferential surface. These screws are engaged with each other to connect the lens holder 32 and the lens fixture 33.

In the image pickup device described so far, each lens must be assembled into a single assembly in order to function. For this purpose, the lenses are stacked in a given order on a casing or frame, commonly called a barrel, or a lens is placed on a given assembly surface. Simple assembly is a common structure.

However, the image pickup lens according to the conventional image pickup apparatus has the following problems. In other words, when the lens is assembled to the barrel, there are thickness tolerances of the individual components of the lens, barrel tolerances, and distance tolerances between the lenses that are generated during assembly. When these tolerances accumulate in a direction that degrades the performance of the lens, The quality of the image formed by this is extremely degraded, thereby causing a decrease in reliability or poor quality of the image pickup device.

Therefore, in order to implement high-resolution excellent performance in a small and lightweight image pickup device applied to a portable device, technical means for minimizing the effects of tolerance accumulation as well as the reduction of tolerances of individual components are required.

It is an object of the present invention to provide a means for adjusting and compensating for the accumulation of tolerances in assembling the lens and barrel assembly in the image pickup device of a camera after completion of assembly.

It is still another object of the present invention to provide an image pickup device in which an accumulation of tolerances in assembling the lens and the barrel assembly in the image pickup device of the camera is adjusted and compensated after the assembly is completed, thereby enabling an image acquisition with high reliability and quality. It is.

It is still another object of the present invention to adjust between the first lens-to-barrel assembly and the second lens-to-barrel assembly so that the tolerance accumulation in assembling the lens and the barrel assembly in the image pickup device of the camera can be adjusted and compensated after the assembly is completed. An image pickup device characterized in that it is configured via means.

It is still another object of the present invention to provide a spring between the first lens-to-barrel assembly and the second lens-to-barrel assembly to compensate for the tolerance accumulation upon assembly of the lens and the barrel assembly in the image pickup device of the camera to compensate for this. An image pickup device comprising means for intervening and adjusting an opposing lens distance of each lens- barrel assembly coupled to each other based on an adjustment of a screwing state between the lens- barrel assemblies.

An image pickup device of the present invention for achieving the above object comprises: a first lens-passage assembly in which a lens is inherent to form an image incident from an object side and which is cylindrical to an optical path; A second lens-tuner assembly in which a lens is inherent and cylindrical in an optical path to form an image with the first lens-tuner assembly; An elastic member interposed between the first lens barrel assembly and the second lens barrel assembly; Wherein the first lens- barrel assembly and the second lens- barrel assembly are connected by screws formed on the respective major surface and the distance between the lenses is adjusted between the elastic members by adjusting the threads. It features.

In the image pickup device according to the present invention, the elastic member is characterized in that the compression spring.

In addition, the image pickup device according to the present invention to form a groove on the surface facing the second lens- barrel assembly of the first lens- barrel assembly in order to support the elastic member and the elastic member is embedded in the groove One end of the to apply an elastic force to the first lens- barrel assembly and the other end to the elastic force to the second lens- barrel assembly.

In addition, in the image pickup device according to the present invention, the first lens- barrel assembly includes a first lens positioned on an object side and a second lens fixed in a stacked manner in close contact with the first lens, and the second lens fixed to the first lens. The lens- barrel assembly may include a third lens facing the second lens and a fourth lens corresponding to an end on the optical path and fixed in a stacked form in close contact with the third lens.

In addition, the image pickup apparatus according to the present invention is characterized in that the distance between the second lens and the third lens is adjusted by adjusting the screw engagement state of the first lens barrel assembly and the second lens barrel assembly.

In addition, in the image pickup device according to the present invention, the first lens- barrel assembly is fixed to be stacked in close contact with the first lens and the first lens having a refractive index that is located on the object side and the emission surface of the image light converges. A second lens having an index of refraction where the incident surface of image light diverges and the emission surface converges, the second lens- barrel assembly having an index of refraction opposite the second lens and the incident and exit surfaces of image light diverging; And a fourth lens corresponding to an end on the third lens and the optical path, and fixed in a form in which the third lens is in close contact with the third lens and having an index of refraction that converges the entrance and exit surfaces of the image light.

In addition, the image pickup device according to the present invention, the first lens and the second lens which is fixed in the form of being stacked on the first lens is fixed to the first lens- barrel assembly is fixed therein; A second lens- barrel assembly having a third lens and a fourth lens tightly fixed in the form of being laminated to the third lens; An elastic member interposed between the first lens- barrel assembly and the second lens- barrel assembly; The lens- barrel assemblies are connected to each other using a screw formed on the surface of the main surface, and form a groove in which the elastic member is inserted and supported on a surface opposite to the second lens- barrel assembly of the first lens- barrel assembly. The other end of the elastic member having one end supported by the groove is opposed to the edge of the third lens, so that the distance between the second lens and the third lens is adjusted as the barrel is rotated so that the accumulated tolerance compensation is achieved. It features.

Hereinafter, with reference to the accompanying drawings will be described an embodiment configuration of the image pickup device according to the present invention and its operation.

As described above, the present invention provides a tolerance by making one or more adjustment means in the barrel, which can greatly affect the resolution performance of the image pickup device, in order to reduce the defects caused by the tolerances generated in the barrel. It is possible to compensate for image degradation of the lens caused by accumulation.

An embodiment of the image pickup device of the present invention for this purpose is shown in Figs. As shown in Figs. 2 to 4, the image pickup device according to the present invention is constructed based on four lenses, and also has a structure in which the first barrel and the second barrel are combined with each other and completed, and the first lens has a first lens. And a second lens is seated, and a third lens and a fourth lens are seated in the second barrel to form a lens- barrel assembly, respectively. The first lens barrel assembly and the second lens barrel assembly are also coupled using threads formed on respective inner and outer surfaces, with compression springs interposed therebetween, to rotate the lens barrel assembly using the threads. This allows the distance between the lenses facing each other in this section to be adjusted to the optimum resolution position.

Fig. 2A shows the cross-sectional structure seen from the side by separating the image pickup device according to the present invention. FIG. 2B shows a state in which the first lens- barrel assembly is assembled in FIG. 2A, and FIG. 2C shows a state in which the second lens- barrel assembly is assembled in FIG. Figure 3 shows a cross-sectional view of a structure in which the first lens barrel assembly and the second lens barrel assembly are completely assembled with springs interposed therebetween.

First, the structure of each component will be described with reference to FIG. 2A. As shown in FIG. 2A, the image pickup apparatus of the present invention includes a first barrel 100, a second barrel 200, a spring 300, a first lens 110, a second lens 120, and a third lens. 210, a fourth lens 220, and a flare stop 230.

The first barrel 100 has a male thread portion 101 formed on the outer circumferential surface thereof, a groove 102 for spring support is formed on the outer circumferential surface in a direction opposite to the second barrel 200, and an opening ( 103 is formed, and forms a cylinder.

The first lens 110 has a refractive index at which the incident surface 111 of the image light is flat and the exit surface 112 emits the image light. A flange 110a is formed at the edge of the first lens 110, an edge 113 is formed in the exit surface direction, and a flat assembly surface 114 is formed in the incident surface direction. . The second lens 120 has a refractive index at which the incident surface 121 of the image light diverges and the emission surface 122 converges.

The second barrel 200 has a female threaded portion 201 formed on the inner circumferential surface, a male threaded portion 202 formed on the outer circumferential surface, an opening 203 for image light output to the rear, and a lens assembly surface. A 204 is formed along the outer circumferential surface of the inner wall and has a cylindrical shape.

The third lens 210 has a refractive index at which the flange 210a is formed at the edge and the incident surface 211 and the exit surface 212 of the image light diverge, and the fourth lens 220 has the flange 220a at the edge. And a refractive index at which the incident surface 221 and the exit surface 222 of the image light converge.

2B illustrates a state in which the first lens 110 and the second lens 120 are assembled to the first barrel 100 in the image pickup device according to the present invention. 2A and 2B, a method of assembling the first lens- barrel assembly will be described.

The flat assembly surface 114 toward the incident surface 111 of the first lens 110 is assembled at a stable position without inclination due to the assembly while contacting the first lens assembly surface 104 of the first barrel 100. . Next, when the second lens 120 is inserted into the edge portion 113 of the flange 110a on the exit surface 112 side of the first lens 110, the second lens 120 may be inserted into the second lens 120. The incident surface 121 is placed in contact with each other, and then an adhesive is applied to an edge portion of the second lens 120, which is a portion where the outer circumferential surface of the second lens 120 and the inner wall surface of the first barrel 100 are in contact with each other. The first lens-tube assembly is completed by bonding or fixing to each other by ultrasonic welding or the like. At this time, the edge portion 113 of the flange 110a of the first lens 110, which is in contact with the incident surface 121 of the second lens 120, may be managed very well due to the characteristics of the molded lens. The distance between 110 and the second lens 120 is managed within a given tolerance.

FIG. 2C illustrates a state in which the third lens 210 and the fourth lens 220 are assembled to the second barrel 200 in the image pickup device according to the present invention, thereby completing the second lens- barrel assembly. 2A and 2C, a method of assembling the second lens- barrel assembly will be described.

The fourth lens 220, the flare stop 230, and the third lens 210 are assembled to the second barrel 200 in order. At this time, the flat assembly surface 223 of the exit surface 222 of the fourth lens 220 is assembled without inclination while abutting the fourth lens assembly surface 204 of the second barrel 200. Next assembled is a flare stop 230, which is to block the abnormally introduced light, and is placed on the flange 220a side of the incident surface 221 of the fourth lens 220. Next, the third lens 210 is placed on the flare stop 230 and the assembly of the second barrel 200 is completed in this state.

Next, one end of the compression spring 300 is inserted into the groove 102 of the first barrel 100, and the first barrel assembly in which the compression spring 300 is fitted to the second lens- barrel assembly is mounted on the first barrel 100. When the screw is inserted into the outer circumferential surface and the screw parts 101 and 201 provided on the inner circumferential surface of the second barrel 200, the image pickup device assembly of the lens- barrel assembly excluding the image sensor is completed. 3 shows a structure in which the assembly is completed.

The image pickup device of the present invention assembled and completed as described above has a structure capable of compensating by adjusting the accumulated tolerance as described above. A method of compensating by adjusting the cumulative tolerance will be described with reference to FIGS. 4A and 4B.

4A shows a state before adjustment and FIG. 4B shows a state after adjustment, respectively, and a resolution inspection jig including a resolution chart 401 and a lamp 402 is prepared for adjustment.

Place the assembled barrel assembly on the prepared resolution inspection jig. At this time, the light of the lamp 402 transmitted through the resolution chart 401 passes through the lenses 110, 120, 210, and 220 to create a transmission image of the resolution chart on the screen. The state of the transmission image 403 shown in FIG. 4A is a state in which various tolerances are generated in the barrel assembly. The transmission image 403 shows a low contrast or a field culvature of a specific region. The quality of the image is low, and the distance between the second lens 120 and the third lens 210 at this time is expressed as "d".

In this state, when the first lens barrel assembly is rotated along the threaded portions 101 and 201 which are formed to engage the barrels 100 and 200, the first lens barrel assembly and the second lens barrel assembly are close to each other. As the distance between the second lens 120 and the third lens 210 changes and the image quality improves accordingly, the position of the image quality is improved. At this time, the rotation is stopped and the two barrels are fixed using separate adhesive means. In this way, the image pickup device having the optimal highest resolution is completed.

As described above, the distance between the second lens 120 and the third lens 210 in the optimally adjusted state is expressed as “d _c ”. In the transmission image 404 after the adjustment, the resolution quality is higher than before the adjustment. It can be seen that the improvement.

In the image pickup device according to the present invention, it is possible to compensate by adjusting the deterioration of the image caused by the tolerances generated in other parts of the barrel by adjusting the distance between the first lens barrel assembly and the second lens barrel assembly. This can greatly improve the defective rate of the product.

Claims (7)

A first lens-passage assembly in which the lens is inherent to form an image incident from the object side and is cylindrical to the optical path; A second lens-tuner assembly in which a lens is inherent and cylindrical in an optical path to form an image with the first lens-tuner assembly; An elastic member interposed between the first lens barrel assembly and the second lens barrel assembly; Image pickup device, characterized in that configured to include. The lens assembly of claim 1, wherein the first lens barrel assembly and the second lens barrel assembly are connected by a thread formed on the respective main surface, and the distance between the lenses is adjusted with the elastic member interposed by thread adjustment. An image pickup apparatus, characterized in that. 2. The method of claim 1, wherein a groove is formed on a surface of the first lens barrel assembly facing the second lens barrel assembly to support the elastic member, and the one end of the elastic member is embedded in the groove. And an elastic force on the first lens-barrel assembly and the other end to the elastic force on the second lens-barrel assembly. 2. The lens assembly of claim 1, wherein the first lens barrel assembly includes a first lens positioned on an object side and a second lens fixed in a stacked manner in close contact with the first lens. And a third lens facing the second lens and a fourth lens corresponding to an end on the optical path and fixed in a form in which the third lens is in close contact with and stacked on the third lens. The image pickup apparatus according to claim 4, wherein the distance between the second lens and the third lens is adjusted by adjusting the screw engagement state of the first lens barrel assembly and the second lens barrel assembly. The first lens- barrel assembly of claim 1, wherein the first lens-passage assembly is positioned on an object side and is fixed in a form of being stacked in close contact with the first lens and having a refractive index where the emission surface of the image light converges. And a second lens having a refractive index that diverges and the emission surface converges, wherein the second lens-passage assembly is opposite to the second lens and has a refractive index that the incident and exit surfaces of the image light diverge; And a fourth lens corresponding to an end on the optical path and fixed in the form of being in close contact with the third lens and laminated, and having a refractive index in which the entrance and exit surfaces of the image light converge. A first lens- barrel assembly having a first lens and a second lens tightly fixed in a stacked manner on the first lens; A second lens- barrel assembly having a third lens and a fourth lens tightly fixed in the form of being laminated to the third lens; An elastic member interposed between the first lens- barrel assembly and the second lens- barrel assembly; The lens- barrel assemblies are connected to each other using a screw formed on the surface of the main surface, and form a groove in which the elastic member is inserted and supported on a surface opposite to the second lens- barrel assembly of the first lens- barrel assembly. The other end of the elastic member having one end supported by the groove is opposed to the edge of the third lens, so that the distance between the second lens and the third lens is adjusted as the barrel is rotated so that the accumulated tolerance compensation is achieved. An image pickup apparatus characterized by the above-mentioned.

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