JP4190104B2 - Imaging device and endoscope using the imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus and an endoscope using the imaging apparatus.
[0002]
[Prior art]
In an image pickup apparatus using an image pickup element used for a digital camera, an electronic endoscope, etc., an axial misalignment in which the center of the image faces obliquely forward instead of the front, an image lateral shift during zooming, and vignetting around a wide-angle lens In order to suppress this, it is essential to match the center of the effective pixel area of the image pickup device that can actually form and output an image with the optical axis of the objective optical system. Conventionally, the effective pixel region is actually measured with a measuring microscope or the like to determine the center, and the center is positioned so that the optical axis of the optical member coincides.
[0003]
[Problems to be solved by the invention]
However, the actual measurement and positioning is inefficient and takes time, leading to an increase in cost. In addition, it is necessary to observe the entire surface of the image sensor with a measuring microscope even during work, and the observation magnification cannot be increased, so the positioning accuracy is not good. Depending on the image pickup device, the boundary line between the pixel area and the effective pixel area is not clear, and the boundary cannot be determined during measurement, resulting in an assembly error.
[0004]
In addition, when positioning and fixing the imaging element and the optical member having a lens function, the effective pixel region may be vignetted at the edge of the optical member and cannot be observed.
[0005]
FIG. 8 is a conceptual diagram when positioning the imaging element and the convex lens. The imaging element 14 has a pixel area 2 and an effective pixel area 3, and a convex lens 12 is fixed thereon. However, when trying to position and fix using the measuring microscope, the refraction action of the convex lens 12 allows observation with the measuring microscope objective lens 11 within the range inside the light beam 13a, and more light rays are vignetted at the edge of the convex lens 12. I can't observe. In order to observe the range beyond the light ray 13a, it must pass through the extended line 12a portion of the incident surface of the convex lens 12 like the light ray 13b. If the convex lens 12 is enlarged so that observation can be performed, the imaging device becomes large, which is not preferable. In particular, it is fatal for a product that is desired to be downsized, such as an endoscope.
[0006]
Even when the imaging device and the lens frame are positioned and fixed, the effective pixel area may be vignetted at the edge of the lens frame, and may not be observed, and cannot be positioned. FIG. 9 shows a conceptual diagram when positioning the imaging device and the lens frame. The image sensor 14 has a pixel area 2 and an effective pixel area 3, and the image sensor 14 is fixed to the lens frame 16. The lens frame 16 is provided with an optical member fixing portion 17 for fixing an optical member arranged in front of the lens frame 16. When trying to position and fix the imaging device 14 and the lens frame 16 using the measurement microscope, the measurement microscope objective lens 11 can be observed within the range inside the light beam 15a, and the light beam beyond that can be seen as the light beam 15b. It is vignetting at the inner edge of the optical member fixing portion 17 and cannot be observed. In order to enable observation, it is necessary to increase the inner diameter of the optical member fixing portion 17, and the optical member disposed in front of the optical member fixing portion 17 is also not preferable. In particular, it is fatal for a product that is desired to be downsized, such as an endoscope.
[0007]
The present invention has been made in view of such problems of the prior art, and an object thereof is to provide an imaging device, an optical member, and an imaging device without enlarging an imaging device such as an endoscope for positioning and fixing the imaging device. Is to improve the positioning accuracy and efficiency.
[0008]
[Means for Solving the Problems]
The imaging device of the present invention that achieves the above object is an imaging device in which an optical element is positioned and fixed to an imaging device having a cover glass.
The optical element is a plano-convex lens closest to the image side of the objective optical system,
The image pickup device is characterized in that an index indicating the position of the pixel region or the effective pixel region is arranged in the vicinity of the pixel region at a position where it can be directly observed through the optical element.
[0010]
The present invention includes an endoscope using such an imaging apparatus.
[0011]
In the present invention, since the index indicating the position of the pixel area or the effective pixel area used to actually form and output an image is arranged in the vicinity of the periphery of the pixel area, the positioning accuracy with the optical member and the efficiency are improved. Thus, it is possible to position the optical member and the lens frame, which cannot be positioned unless the imaging apparatus is enlarged in the conventional method.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of an imaging device and an endoscope using the imaging device of the present invention will be described.
[0013]
(First embodiment)
FIG. 1 shows a simplified diagram of the CCD of the first embodiment. There is a pixel area 2 in the imaging surface of the CCD 1, and an effective pixel area 3 in it. Indicators 4a, 4b, 4c, and 4d are arranged around the pixel region 2. The indexes 4a, 4b, 4c, and 4d are arranged at the centers of the effective pixel region in the vertical and horizontal directions, respectively, and the intersection of the lines connecting the indexes arranged in the vertical and horizontal directions becomes the center of the effective pixel region. Thus, the center of the effective pixel region can be easily obtained.
[0014]
In the product using the CCD described in the present embodiment, it is not necessary to measure the effective pixel region 3 to obtain the center, so that the assembly efficiency can be improved and the cost can be reduced.
[0015]
In the embodiment of FIG. 1, the indicators 4a to 4d are small circles, but the shape of the indicator may be any shape such as a triangle, a cross, or a straight line.
[0016]
(Second embodiment)
FIG. 2 shows a simplified diagram of the CCD of the second embodiment. There is a pixel area 2 in the imaging surface of the CCD 1, and an effective pixel area 3 in it. Indicators 5 a and 5 b are arranged around the pixel region 2. The index 5a is arranged on the upper peripheral part of the pixel area 2 so as to be shifted to the right by a predetermined distance from the center of the upper side of the effective pixel area 3, and the index 5b is located on the right peripheral part of the effective pixel area 3 on the right peripheral part of the pixel area 2. It is arranged to be shifted upward by a predetermined distance from the center. When determining the center of the effective pixel region 3, the predetermined distances in the left direction and the downward direction from the positions of the indices 5a and 5b may be converted.
[0017]
In the CCD described in this embodiment, the boundary between the pixel area 2 and the effective pixel area 3 is not clear, and it is easy to cause an assembly error in which the optical axis and the center of the effective pixel area 3 are shifted from each other. Assembling errors can be reduced by arranging the simple indicators 5a and 5b. In addition, since all the indicators 5a and 5b are arranged on the upper right side of the imaging surface, the observation range with the measuring microscope when the center of the effective pixel region 3 is obtained can be seen as a quarter of the effective pixel region 3 in the upper right direction. Since this is sufficient, the observation magnification can be increased. As a result, the assembly accuracy of the used product can be improved, and the performance of the product can be improved and the cost can be reduced.
[0018]
Thus, the index does not have to be particularly near the center of each side, and only the positional relationship with the center of the effective pixel region needs to be clear.
[0019]
(Third embodiment)
FIG. 5 is a sectional view of the endoscope objective optical system according to the third embodiment. FIG. 3 shows a simplified diagram of the CCD 1 used in the third embodiment. FIG. 4 is a simplified diagram showing the positional relationship between the CCD 1 and the lens 7b of the endoscope objective optical system. The indices 6a and 6b shown in FIGS. 3 and 4 are arranged at the centers of the upper and lower sides of the effective pixel region 3, and are formed of a chromium oxide-chromium-chromium oxide vapor deposition film having a low reflectance. The endoscope objective lens shown in FIG. 5 includes two convex lenses 7a and 7b, which are adhered to the cover glass of the CCD 1 on the plane of the image side surface of the convex lens 7b disposed on the image side. A convex lens 7a is arranged with reference to the outer diameter.
[0020]
In the conventional imaging device, even if the effective pixel region 3 is measured with the measuring microscope through the convex lens 7b, the lateral periphery is vignetted at the edge of the lens 7b and cannot be observed. I could not.
[0021]
In this embodiment, since the indexes 6a and 6b are arranged at the center position in the horizontal direction, when positioning is performed, the length included in the effective pixel region 3 of the line connecting the indexes 6a and 6b through the convex lens 7b. The center of the effective pixel region 3 is obtained by measuring the height with a measuring microscope and obtaining the center thereof.
[0022]
In this objective optical system, when the conventional imaging device is used, the lateral periphery of the effective pixel region 3 cannot be observed with a measurement microscope, and therefore the effective pixel region 3 and the convex lens 7b cannot be positioned. By disposing the indexes 6a and 6b, the convex lens 7b can be positioned and fixed, and axial deviation and peripheral vignetting can be suppressed, so that the performance of the endoscope imaging apparatus can be improved. In addition, since the indicators 6a and 6b are formed of a low-reflectance chromium oxide-chromium-chromium oxide layer structure, reflected light from the indicators 6a and 6b can be suppressed, and flare does not occur.
[0023]
If an index corresponding to the index of the image sensor is provided on the eyepiece side or the observation side of the measurement microscope, the center can be obtained without performing the measurement.
[0024]
In addition, when the index indicating the position of the member fixed to the image sensor is aligned with the index of the measurement microscope, the positioning can be easily performed.
[0025]
In addition, as the substance forming the index, a substance whose reflectance is lowered by coloring with an organic substance or the like can be used.
[0026]
(Fourth embodiment)
FIG. 6 shows a simplified diagram of an endoscope CCD frame and CCD used in the fourth embodiment. FIG. 7 is a simplified diagram showing the positional relationship between the endoscope CCD used in the fourth embodiment and the lens fixing portion of the CCD frame. In this embodiment, the CCD 1 is positioned and fixed with respect to the CCD frame 8. The CCD frame 8 is provided with a lens fixing portion 9 for fixing the objective lens. The inner diameter central axis coincides with the optical axis of the objective optical system.
[0027]
In the conventional imaging device, the peripheral portion in the lateral direction of the effective pixel region 3 is vignetted at the edge of the lens fixing portion 9 of the CCD frame 8 and cannot be observed or measured. Therefore, the two indicators 10a, 10b, An index 10c is arranged in the downward direction. The indicators 10a and 10b are arranged horizontally with the upper side of the effective pixel region 3 so that the midpoint between the two points is the center of the upper side of the effective pixel region 3, and the indicator 10c is arranged at the center of the lower side of the effective pixel region 3. Yes. When positioning, the positioning is performed while looking at the horizontal of the indicators 10a and 10b, so that the rotation (twisting) direction of the CCD 1 and the CCD frame 8 can be easily adjusted.
[0028]
In this embodiment, since the periphery of the effective pixel region in the horizontal direction cannot be observed with the measuring microscope, conventionally, the effective pixel region 3 and the CCD frame 8 cannot be positioned. However, the indicators 10a to 10c as described above are arranged. As a result, positioning can be performed, and the axial displacement and vignetting of the peripheral portion of the endoscope imaging apparatus can be suppressed, and the performance of the endoscope can be improved.
[0029]
Similarly, when a protective parallel plate for avoiding dust is arranged in front of the image sensor, the objective lens can be arranged with reference to the outer diameter by positioning and arranging with reference to the index. In addition, misalignment of the image pickup apparatus and peripheral vignetting can be easily suppressed.
[0030]
In this embodiment, in order to easily adjust the rotation (twist) direction of the CCD 1 and the CCD frame 8, the two index points 10a and 10b are arranged horizontally, but a horizontal linear index is arranged in the pixel area 2. However, the same effect can be obtained.
[0031]
The above-described imaging device, endoscope using the imaging device, and further, an endoscope imaging device assembling method can be configured as follows, for example.
[0032]
[1] An imaging device, wherein an index indicating the position of a pixel area or an effective pixel area used to actually form and output an image is arranged in the vicinity of the periphery of the pixel area.
[0033]
[2] An imaging device, wherein an index indicating the center of a pixel region or an effective pixel region used to actually form and output an image is arranged in the vicinity of the periphery of the pixel region.
[0034]
[3] The imaging device as described in 1 or 2 above, wherein two or more indicators are arranged.
[0035]
[4] The imaging device according to any one of 1 to 3, wherein the index is made of a material having a low reflectance.
[0036]
[5] An imaging apparatus comprising a member having an axis substantially coincident with the optical axis of the objective optical system fixed to the imaging element according to any one of 1 to 4 above.
[0037]
[6] An imaging apparatus comprising an optical member fixed to the imaging element according to any one of 1 to 4 above.
[0038]
[7] The imaging apparatus according to [6], wherein the optical member fixed to the imaging element has a lens action.
[0039]
[8] An endoscope using the imaging device according to any one of 1 to 4 or the imaging device according to any one of 5 to 7.
[0040]
[9] It is characterized in that a positional relationship between an index arranged in the vicinity of the imaging region of the imaging device and a member having an axis substantially coincident with the optical axis of the optical member or the objective optical system is obtained and fixed. A method for assembling an endoscope imaging apparatus.
[0041]
【The invention's effect】
As is clear from the above description, in the present invention, since the index indicating the center position of the pixel region of the image sensor or the effective pixel region that actually forms and outputs an image is provided in the vicinity of the periphery of the pixel region, It is possible to improve the accuracy and efficiency of positioning, and to position a member that could not be positioned unless the imaging device is enlarged in the conventional method.
[Brief description of the drawings]
FIG. 1 is a simplified diagram of a CCD according to a first embodiment of the present invention.
FIG. 2 is a simplified diagram of a CCD according to a second embodiment of the present invention.
FIG. 3 is a simplified diagram of a CCD used in a third embodiment of the present invention.
FIG. 4 is a simplified diagram showing a positional relationship between a CCD and a lens of an endoscope objective optical system in a third embodiment.
FIG. 5 is a cross-sectional view of an endoscope objective optical system according to a third embodiment.
FIG. 6 is a simplified diagram of an endoscope CCD frame and CCD used in a fourth embodiment of the present invention.
FIG. 7 is a simplified diagram showing a positional relationship between an endoscope CCD used in a fourth embodiment and a lens fixing portion of a CCD frame.
FIG. 8 is a conceptual diagram when positioning an imaging element and a convex lens for explaining the prior art.
FIG. 9 is a conceptual diagram when positioning an image sensor and a lens frame for explaining a conventional technique.
[Explanation of symbols]
1 ... CCD
2... Pixel area 3... Effective pixel areas 4 a, 4 b, 4 c, 4 d, 5 a, 5 b, 6 a, 6 b, 10 a, 10 b, 10 c ... Index 7 a, 7 b ... Convex lens 8 for the endoscope objective optical system 8. ... Lens fixing part 11 ... Measuring microscope objective lens 12 ... Convex lens 13a ... Light beam 13b that can be observed ... Light beam 14 that cannot be observed by vignetting ... Image sensor 15a ... Light beam 15b that can be observed ... Light beam 16 that cannot be observed by vignetting ... Lens frame 17 ... Optical member fixing Part

Claims (7)

In an imaging device in which an optical element is positioned and fixed to an imaging device having a cover glass,
The optical element is a plano-convex lens closest to the image side of the objective optical system,
The imaging device, wherein an index indicating a position of a pixel region or an effective pixel region is arranged in the vicinity of a pixel region at a position where it can be directly observed through the optical element . The imaging apparatus according to claim 1, wherein the optical element is directly bonded to a cover glass of the imaging element. The image pickup apparatus according to claim 1, wherein the pixel region of the image pickup element is a square, and the indices are arranged at two or more locations on two or more sides.   The imaging apparatus according to claim 3, wherein the index is arranged at two or more locations on two opposite sides of the pixel region.   The imaging apparatus according to claim 3, wherein the index is arranged at two or more locations on two orthogonal sides of the pixel region.   6. The imaging apparatus according to claim 3, wherein at least one index is arranged near the center of the side.   An endoscope using the imaging apparatus according to any one of claims 1 to 6.

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