JP2005217546A - Electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the dust stuck to a spacer from sticking to an image pickup element and an optical member as a result of moving in a space between the image pickup element and the optical member. <P>SOLUTION: The electronic camera has: the image pickup element 2 which receives a transmitted light flux of a photographing lens and converts it to an electric image signal; the optical member 1 arranged between the photographing lens and the image pickup element; and the spacer 3 which is clamped at each non-effective region outside part of the optical member 1 and the image pickup element 2 and forms a space SP between both of them. Adhesiveness is imparted to at least a part 3a1 facing the space of the spacer 3. For example, a solution in which an adhesive is dissolved in a volatile solvent may be applied to the part 3a1, or the spacer may be composed of an intrinsically adhesive rubber material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic camera, and more particularly, to an anti-dust measure for an image sensor or an optical member.

  The electronic camera receives a photographic light beam that has passed through the photographic lens with an image sensor such as a CCD or CMOS, converts the photoelectric conversion output into image data, and records the image data on a recording medium. In many cases, an optical low-pass filter (OLPF) is disposed between the imaging element and the photographing lens. In such a camera, when dust such as dust adheres to the image sensor or the optical low-pass filter, the dust is reflected in the photographed image and the appearance of the image is deteriorated. In particular, in an electronic camera capable of exchanging lenses, external dust is likely to enter the camera body from the opening of the lens mount during lens replacement, and dust is also likely to be generated from mechanical operating parts such as a shutter and an aperture control mechanism.

  In the camera equipped with the optical low-pass filter, the gap between the filter and the image sensor is used as a sealed space to prevent dust from entering, and when dust adheres to the surface of the optical member, it can be removed by cleaning and further removed. Some of them are provided with a member (such as an adhesive tape) for catching dust (for example, see Patent Document 1). The optical member can be cleaned by the service center or by the user. In either case, the camera is set to the cleaning mode (the mode in which the mirror and shutter are held in the up state and the open state, respectively), and the mount opening Then, the cleaning member is inserted to remove dust attached to the surface of the low-pass filter.

JP 2003-156787 A JP 2002-122902 A

  Although the space between the optical low-pass filter and the image sensor is unlikely to enter external dust after assembly of the camera, dust may enter during assembly. At the time of assembly, dust removal work is performed on the low-pass filter, the image sensor, and the spacers arranged between them in advance. There is a possibility that dust floats in the space due to vibrations when the camera is used, and moves to the protective glass of the image sensor or the back surface of the low-pass filter. The dust attached to the surface of the low-pass filter can be removed relatively easily in the cleaning mode, but the dust attached to the protective glass and the back surface of the low-pass filter cannot be removed unless the camera is disassembled.

An electronic camera according to the first to third aspects of the present invention includes an imaging element that receives a transmitted light beam of a photographing lens and converts it into an electrical image signal, and an optical member that is disposed between the photographing lens and the imaging element. A spacer is interposed between the optical member and the outside of each ineffective area of the image sensor, and a spacer is formed between the two, and at least a portion of the spacer facing the space is made sticky.
In particular, the invention of claim 2 applies a solution in which an adhesive is dissolved in a volatile solvent to at least a portion of the spacer facing the space.
In the invention of claim 3, the spacer is made of rubber having adhesiveness.
According to a fourth aspect of the present invention, there is provided an electronic camera having an image sensor that receives a transmitted light beam of a photographing lens and converts it into an electrical image signal, and an optical member disposed between the photographing lens and the image sensor. The surface of the optical member that is receded to the image pickup element side from the light incident surface of the optical member is formed in at least one place, and the receding surface is made sticky.

According to the first aspect of the present invention, a space is provided between the optical member and the imaging element by the spacer, and at least a portion of the spacer facing the space is made sticky. The possibility that the attached dust moves to the back surface of the image sensor or the optical member is reduced, and thus deterioration of the image can be suppressed.
According to the fourth aspect of the present invention, at least one surface that is retreated to the image pickup element side from the light incident surface of the optical member is formed around the optical member, and the retreated surface is made adhesive. Further, it is possible to reduce the possibility that dust discharged from the light incident surface of the optical member to the surface is directly captured by the surface and move to the optical member again, thereby preventing image deterioration.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic sectional view of a camera according to the present invention, and reference numeral 104 denotes a camera body. A part of the photographic light beam 100 transmitted through the lens 107 is reflected upward by the semi-transmissive main mirror 101 and observed by the eyepiece lens 106 through the pentaprism 105. On the other hand, a part of the light beam transmitted through the main mirror 101 is reflected by the sub mirror 102 and guided to a focus detection unit (not shown). A shutter 103 is disposed behind the mirrors 101 and 102, an optical low-pass filter (hereinafter referred to as an OLPF) 1 is disposed behind the shutter 103, and an imaging element 2 such as a CCD is further disposed behind the shutter 103.

  At the time of shooting, the mirrors 101 and 102 are flipped up and retracted from the shooting optical path, the shutter 103 is opened, and the light beam 100 enters the image sensor 2 through the opening of the shutter 103 and the OLPF 1. The image sensor 2 receives a light beam on its light receiving surface, outputs an electrical image signal corresponding to the received light beam, and an image processing circuit (not shown) performs various processes on the image signal to generate image data. The generated image data is recorded on a memory card or the like.

The structure of the imaging unit including the imaging device 2 and the OLPF 1 will be described in detail with reference to FIGS.
The imaging device 2 has a protective glass 2c on the front surface of the light receiving surface, and the back surface is fixed to the fixing member 4 by adhesion or the like. Reference numeral 5 denotes an imaging substrate on which the imaging element 2 is mounted, and is fixed to the back surface of the fixing member 4 with screws 10a. The OLPF 1 is disposed on the front side of the protective glass 2c with the rubber spacer 3 interposed therebetween.

  The spacer 3 does not directly contact the OLPF 1 and the protective glass 2c, and a space SP is formed between the effective areas of both. Accordingly, it is possible to prevent the OLPF 1 and the protective glass 2c from being damaged when assembled. Further, by interposing the spacer 3, the distance between the light receiving surface of the image sensor 2 and the surface of the OLPF 1 (the surface on the photographing lens side, that is, the light incident surface) can be increased. If dust adheres to the surface of the OLPF 1, it appears in the image. However, as the distance is longer, the dust image can be blurred and image deterioration can be suppressed. As shown in FIG. 5, the spacer 3 has a substantially rectangular opening OP for transmitting the photographing light beam 100, and a peripheral portion (a sandwiched portion) 3 a is sandwiched between the ineffective regions of the OLPF 1 and the protective glass 2 c. .

  A rectangular annular pressing member 6 is disposed on the surface side of the OLPF 1. As can be seen from FIG. 4, a step is provided at both ends of the OLPF 1 in the short direction, the long side portion of the pressing member 6 is in contact with the step portion (low portion), and the short side portion of the pressing member 6 is in contact with the spacer 3. Touch. Reference numeral 7 denotes a spring member having a pair of spring portions 7a, and the four portions are screwed to the fixing member 4 by screws 10b in a state where the spring portion 7a presses the short side portion of the pressing member 6. As a result, the OLPF 1, the image pickup device 2, the spacer 3, the substrate 4 and the like are integrated to form an image pickup unit, and the image pickup unit is fixed to the camera body 104 with screws 10c.

  Since each ineffective area of the OLPF 1 and the protective glass 2c presses the clamped portion 3a of the spacer over four sides by the spring force of the spring member 7, the clamped portion 3a is compressed and deformed so that both the members 1 and 2 are compressed. The space SP is more tightly sealed. Therefore, the possibility that dust enters the space SP from the outside after the imaging unit is assembled is extremely low. On the other hand, at the time of assembly, dust removal is performed on each component in advance, but fine dust that could not be removed is enclosed in the space SP, which may adhere to the OLPF 1 or the protective glass 2c after assembly. . In particular, since the front end surface 3a1 (FIG. 6) of the sandwiched portion 3a of the spacer 3 faces the space SP, when assembled with dust attached thereto, the dust floats in the space SP and becomes OLPF1. Alternatively, the protective glass 2c may be reached and the image may be deteriorated.

  Therefore, in this embodiment, the spacer 3 is made sticky so that the movement of dust attached to the spacer 3 is prevented. In order to give the tackiness, a solution in which an adhesive was dissolved in a volatile solvent was prepared in advance, and the entire spacer was immersed in the solution before assembly. The immersion time may be instantaneous, and the volatile solvent evaporates immediately after being pulled up, but the adhesiveness of the adhesive remains in the entire spacer. According to this method, it is possible to perform the work of imparting adhesiveness to the spacer 3 in a very short time, and the work efficiency is good. In addition, since a volatile solvent is used, the solvent oozes out during assembly and enters the OLPF 1 and the image sensor 2. There is no adverse effect. Of course, an adhesive may be applied only to a necessary portion of the spacer 3, or a double-sided tape may be attached. However, both are time consuming and work efficiency is poor.

  By giving the spacer 3 stickiness in this way, even if dust adheres to any of the spacers 3 before assembly, the dust is not caught and floats as it is, and the back surface of the OLPF 1 and the protective glass The possibility of dust reaching 2c can be reduced. Therefore, it is not necessary to carefully clean the spacer 3 prior to assembly, and it is only necessary to remove noticeable dust, and work efficiency can be improved.

  Further, giving the spacer 3 adhesiveness is also effective for dust outside the space SP. External dust adheres to the surface of the OLPF 1 to cause image degradation. As described in the background art, the dust can be discharged from the surface of the OLPF 1 by setting the camera to the cleaning mode. In this embodiment, a part 3b of the surface of the spacer 3 is exposed outside both ends in the longitudinal direction of the OLPF 1, and the exposed surface 3b is lower than the surface of the OLPF 1 (retreats to the image sensor side). The dust adhering to the surface of the OLPF 1 can be easily removed onto the exposed surface 3b using the cleaning member. Since the exposed surface 3b has adhesiveness, the dust removed here is captured as it is, and the possibility of returning to the surface of the OLPF 1 is low.

  Incidentally, the camera disclosed in Japanese Patent Application Laid-Open No. 2003-156787 (Cited Document 1) is also provided with a dust catching member such as an adhesive tape. Is likely to fall to another position without reaching the capturing member and return to the surface of the OLPF 1.

  The adhesive force of the spacer 3 may be very weak because it is intended to capture dust. If the adhesive force is too strong, the assembly of the image pickup unit is hindered or cannot be disassembled when replacing damaged parts, and the entire unit must be replaced, resulting in an increase in cost. Therefore, it is necessary to have an adhesive force that does not hinder assembly / disassembly operations while having sufficient dust capturing capability. Needless to say, the adhesiveness must be able to exert its effect over a certain period of time.

  In addition to the spacer 3, the pressing member 6 and the spring member 7 may have adhesiveness. Further, the optical member disposed between the photographing lens and the image sensor is not limited to the low pass filter. Further, the spacer may be made of rubber having an adhesive property without using an adhesive. Further, a place (a place having adhesiveness) for removing dust attached to the surface of the OLPF is not limited to the spacer.

The side sectional view of the electronic camera in one embodiment. The top view which looked at the imaging unit of the electronic camera from the optical axis front. III-III sectional view taken on the line of FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. The perspective view which shows the spacer which comprises an imaging unit. The expanded sectional view which shows a part of protective glass of an image pick-up element, an optical low pass filter, and a spacer.

Explanation of symbols

1 Optical low pass filter (OLPF)
2 Image sensor 2c Protective glass 3 Spacer 3a Clamped portion 3a1 Tip surface 3b Exposed surface 4 Fixed member 5 Imaging substrate 6 Pressing member 7 Spring member 103 Shutter 107 Shooting lens Space between SP OLPF and protective glass

Claims (4)

An image sensor that receives the transmitted light flux of the photographic lens and converts it into an electrical image signal;
An optical member disposed between the photographing lens and the imaging element;
A spacer that is sandwiched between the optical member and the outside of each ineffective area of the image sensor, and that forms a space between the two;
An electronic camera characterized in that at least a part of the spacer facing the space is made sticky. The electronic camera according to claim 1, wherein a solution obtained by dissolving an adhesive in a volatile solvent is applied to at least a portion of the spacer facing the space. The electronic camera according to claim 1, wherein the spacer is made of adhesive rubber. An image sensor that receives the transmitted light flux of the photographic lens and converts it into an electrical image signal;
An optical member disposed between the imaging lens and the imaging element;
The electronic member is characterized in that at least one surface is formed around the optical member so as to recede from the light incident surface of the optical member toward the image pickup device, and the receding surface is made adhesive. camera.

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