JPH11313235A - Optical device for photographing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device by which cost is reduced and an optical axis between a photographing lens and an image pickup element is aligned with high accuracy with simple configuration. SOLUTION: The display device 10 includes an image pickup optical system 12 that is supported in a lens mirror barrel 11, an optical element 13 consisting of a parallel plane member placed behind the image pickup optical system 12, and an image pickup element 14 placed behind the optical member. A front side of the optical element 13 at its incidence side is fixed to a rear end of the lens mirror barrel 11 integrally and a front side of a seal glass plate 14C configuring the incident face of the image pickup element 14 is adhered to a front side of an emission side of the optical element 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device for photographing comprising an image pickup device, an image pickup optical system, and an optical device such as a filter.

[0002]

2. Description of the Related Art Conventionally, for example, an optical device for a video camera as such an optical device is configured as shown in FIG. In FIG. 4, an optical device 1 is provided behind an image pickup lens 3 and at least one image pickup lens 3 supported in a lens barrel 2, and in the case of FIG. And an image sensor 5 disposed behind the filter 4.

The filter 4 is a filter such as a quartz filter or an infrared cut filter adapted to the characteristics of the image pickup device, and is composed of a parallel plane member having an incident surface and an exit surface arranged perpendicular to the optical axis. Have been. The filter 4 is inserted into a filter mounting portion 2a provided at the rear of the lens barrel 2.

The image pickup device 5 comprises a chip 5a such as a CCD (charge coupled device), a package 5b for holding the chip 5a, and a sealing glass 5c for sealing the chip 5a in the package 5b on the front surface. , And is fixed to the holder 6 by adhesion or the like. The holder 6 is attached to the rear end of the lens barrel 2,
It is fixed by a screw 6a.

[0005] At this time, the holder 6 has a positioning hole 6b. The positioning hole 6b is fitted to a positioning pin 2b provided on the rear end surface of the lens barrel 2, so that the lens barrel 2 is moved. It is positioned at a predetermined position with respect to the rear end face. Further, when the holder 6 is attached to the rear end of the lens barrel 2, a seal rubber 7 is inserted between the front surface of the image sensor 5 and the filter 4.
As a result, the front surface of the imaging element 5 presses the filter 4 into the filter mounting portion 2a of the lens barrel 2 via the seal rubber 7, and the filter 4 is fixed and held in the lens barrel 2. I have.

According to the video camera optical device 1 having such a configuration, the imaging lens 3, the filter 4, and the imaging device 5
When any one of them is deteriorated due to aging or the like, it is configured to be easily disassembled so that the minimum parts can be individually replaced.

[0007]

However, the center of the optical axis of the imaging lens 3 or the center of the effective image circle and the center of the effective screen of the image sensor 5 are large due to the accumulated errors in the accuracy of each component and the positioning accuracy. There has been a problem that displacement may occur. Here, even if the screen size of the image sensor decreases, the size of the displacement cannot be reduced in proportion to the screen size. Therefore, the effective image circle diameter (angle of view) is increased by the estimated cumulative error. To prevent vignetting on the screen,
It is necessary to design a wide angle of view. Therefore, there is a problem that the size of the imaging lens cannot be reduced in proportion to the reduction in the screen size.

Further, the alignment of the optical axes of the imaging lens 3 and the imaging device 5 is adjusted by positioning the holder 6 and the lens barrel 2, that is, by fitting the positioning hole 6b of the holder 6 and the positioning pin 2b of the lens barrel 2. In this case, it is also possible to adjust the optical axis while observing the screen of the image sensor 5 by tightening the screw 6a by providing the fitting play. However, also in this case, the holder 6 and the lens barrel 2 may be relatively slightly shifted due to the tightening of the screw 6a. Therefore, such an adjustment method also has a problem that effective adjustment is not effective when the screen size of the image sensor is reduced.

Further, since the holder 6, the screw 6a and the sealing rubber 7 are used to fix and hold the filter 4 and the image pickup device 5 with respect to the lens barrel 2, the number of parts is increased, and the cost of parts and cost are reduced. There has been a problem that the assembly cost is increased.

The present invention has been made in view of the above points, and has a simple structure to reduce the cost and align the optical axis between the imaging lens and the imaging device with higher accuracy.
It is an object to provide an optical device for a video camera.

[0011]

According to the present invention, there is provided an imaging optical system supported in a lens barrel, an optical element disposed behind the imaging optical system, and An image pickup element disposed rearward, wherein the optical element has an incident side surface fixed and held integrally to a rear end of the lens barrel, and the incident side of the image pickup element is This is achieved by an imaging optical device in which a constituent surface is fixedly held by an adhesive on a surface on the emission side of the optical element.

According to the above arrangement, the optical element is attached to the rear end of the lens barrel by thermal caulking or bonding, and the image pickup element is bonded to the surface on the emission side of the optical element. By this, it is directly attached to the optical element. Accordingly, since a seal rubber, a holder, and the like are not required to attach the optical element and the imaging element to the lens barrel, the number of parts is reduced, and the cost of parts and the cost of assembly are reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows the configuration of an embodiment of a photographing optical apparatus to which the present invention is applied. In FIG. 1, a photographing optical device is, for example, for a video camera, and a video camera optical device 10 has at least one lens supported in a lens barrel 11, and two lenses 1 in the illustrated case.
An imaging lens 12 composed of 2a and 12b;
Filter 13 as an optical element disposed behind
And an image sensor 14 arranged behind the filter 13
And In the following description, the subject side of the camera is referred to as the front, and the direction away from the subject is referred to as the rear.

The lens barrel 11 has a substantially hollow cylindrical shape, supports a lens 12a near the front end, and supports a lens 12c near the center. Further, the lens barrel 11 has an outer diameter portion 11a formed with high precision for positioning, and a flange portion 11b projecting outward from a rear edge thereof, on the outer side near the front end, and at the rear end. Is provided with a filter mounting portion 11c for receiving the filter 13.

The filter 13 as an optical element is a filter block in which a quartz filter 13a and an infrared cut filter 13b are integrally joined to each other in advance according to the characteristics of the image pickup element. It is composed of parallel plane members arranged perpendicular to the axis.
The filter 13 is inserted from the rear into a filter mounting portion 11c provided at the rear of the lens barrel 11, and the rear edge of the lens barrel 11 is deformed by heat caulking, so that the inside of the filter mounting portion 11c is deformed. Is fixedly held. Here, the fixing of the filter 13 is not limited to thermal caulking, and may be performed by bonding or the like.

The image pickup device 14 is a chip 1 such as a CCD.
4a, a package 14b for holding the chip 14a, and a sealing glass 14c for sealing the chip 14a in the package 14b on the front surface. Then, the imaging element 14 has a front surface of the sealing glass 14c attached to an emission side surface of the filter 13 attached to the rear end of the lens barrel 11 with an ultraviolet-curing adhesive (not shown).
Glued. After the image sensor 14 is bonded to the filter 13, a light-shielding film is formed on the peripheral surface thereof.
This light-shielding film is formed, for example, by applying a light-shielding paint.

The video camera optical device 10 according to the present embodiment is configured as described above, and the adjustment of the optical axis alignment of the image pickup device 14 is performed as shown in FIG. That is, in FIG. 2, a chart holding member 20 for holding a chart 21 for positioning is fitted to the front end of the lens barrel 11 fixed by holding means (not shown). The chart holding member 20 has an inner diameter substantially equal to the outer diameter of the outer diameter portion 11a of the lens barrel 11,
When the end portion abuts on the flange portion 11b, the end portion is accurately positioned with respect to the lens barrel 11, and the chart 2
One center position 21 a is arranged on the optical axis of the imaging lens 12.

From this state, power is supplied to the image pickup device 14, and its output signal is taken out, and an image pickup screen is displayed on a monitor by a processing circuit (not shown). Then, while watching the imaging screen, the seal glass 14c of the imaging element 14 is slid while being in contact with the surface on the emission side of the filter 13, so that the center position 21a of the chart 21 coincides with the center of the imaging screen. Thereby, the optical axis alignment of the imaging device 14 with respect to the imaging lens 12 is completed, and the position of the imaging device 14 is fixed.

Then, by being irradiated with ultraviolet rays,
The ultraviolet curing adhesive is cured. The irradiation of the ultraviolet rays is performed from the front of the optical device 10 via the imaging lens 12. The individual lenses 1 of the imaging lens 12
When the materials 2a and 12b use a material having a low ultraviolet transmittance for correcting chromatic aberration, irradiation of ultraviolet light is performed as shown in FIG.

FIG. 3 shows a modification of the optical device for a video camera shown in FIG. 1. Since the portions denoted by the same reference numerals as those in FIG. 1 have the same configuration, the following description will focus on the differences. The lens barrel 11 has a light guide hole 11c on a side surface in a region between the imaging lens 12 and the filter 13. Then, from the light guide hole 11c, an oblique reflection surface 22a
A light guide 22 having a
UV light enters the light guide 22 through the condenser lens 24 from the light source, the UV light is reflected by the reflection surface 22a provided at the tip of the light guide 22, and the light is filtered through the lens barrel 11 along the optical axis. In the direction 13, the light reaches the ultraviolet curable adhesive between the filter 13 and the imaging device 14 via the filter 13. Thus, the ultraviolet-curable adhesive is cured by irradiation with ultraviolet light.

In the optical device 10 for a video camera assembled in this manner, the image pickup device 14 is directly attached to the lens barrel 11 via the filter 13, so that the conventional seal rubber 7 and holder 6 are used. Further, the mounting screw 6a becomes unnecessary, the number of parts is reduced, and the parts cost and the assembly cost are reduced. The optical axis of the image sensor 14 with respect to the imaging lens 12 is adjusted by observing the image plane of the image sensor 14 on the emission-side surface of the filter 13 fixed to the rear end of the lens barrel 11. The sliding is performed by sliding the surface of the sealing glass 14c in contact with the surface of the sealing glass 14c, and thereafter the glass is fixed with an adhesive, so that the optical axis alignment is performed with high accuracy, and no displacement occurs during the fixing.

Accordingly, the effective image circle diameter (angle of view) of the imaging lens 12 does not need to be increased more than necessary, so that the imaging lens 1
2 will be miniaturized. Further, the image sensor 14
After being adhered to the filter 13, a light-shielding film (not shown) is formed on the peripheral surface of the
No disturbance light other than the light incident through the imaging lens 12 is incident on the fourth chip 14a. Therefore, the image sensor 14 is not affected by disturbance light.

As described above, in the above-described embodiment, after the optical axis of the image pickup device 14 is adjusted with respect to the image pickup optical system while observing the image pickup screen, the image pickup device 14 is adhered to the surface on the emission side of the optical element 13. Therefore, by observing the actual imaging screen by the imaging element, the optical axis alignment is performed with high accuracy, and the imaging element is fixed and held with respect to the lens barrel by bonding. In this case, no displacement due to the tightening occurs, and accurate optical axis alignment is maintained even after fixing and holding. Therefore, the effective image circle diameter (angle of view) of the imaging optical system does not need to be made wider than necessary, and the imaging optical system is configured to be small.

Further, since the image pickup device 14 is adhered to the surface on the emission side of the optical element 13 with an ultraviolet curable adhesive, the ultraviolet curable adhesive is cured by the irradiation of ultraviolet light, so that the adhesive is cured. The curing time is short, and the productivity is improved.

The curing of the ultraviolet-curable adhesive is performed by irradiating the ultraviolet ray through the imaging optical system, so that the ultraviolet ray can be easily irradiated without modifying the optical apparatus. Become.

The ultraviolet curing adhesive is cured by irradiating ultraviolet rays through a light guide hole provided on a side surface between the imaging optical system of the lens barrel and the optical element. Therefore, even when the transmittance of the ultraviolet light is low for correcting the chromatic aberration of the imaging optical system, the irradiation of the ultraviolet light is performed by introducing the ultraviolet light through the light guide hole on the side surface of the lens barrel. Become.

Since the light shielding film is provided on the peripheral surface of the image pickup device after the image pickup device is bonded, it is possible to surely prevent disturbance light from other than the image pickup optical system from entering the image pickup device. Become.

In the above-described embodiment, the imaging lens 12 has a two-group, two-element configuration. However, the present invention is not limited to this, and it is apparent that an arbitrary lens configuration may be used. In the above-described embodiment, the filter 13 is configured as a filter block in which the crystal filter 13a and the infrared cut filter 13b are integrally joined to each other in advance. Obviously, an arbitrary configuration according to the characteristics, for example, a single filter or a multiple filter block is used.

[0030]

As described above, according to the present invention, the cost can be reduced and the optical axis of the image pickup lens and the image pickup device can be aligned with higher accuracy by a simple structure. An imaging optical device is provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of an embodiment of a photographing optical device according to the present invention.

FIG. 2 is a schematic diagram illustrating adjustment of optical axis alignment between an imaging element and an imaging lens of the optical device for photographing of FIG. 1;

FIG. 3 is a schematic view showing an example of ultraviolet irradiation for curing an ultraviolet-curable adhesive in the optical device for photographing of FIG. 1;

FIG. 4 is a schematic sectional view showing an example of a conventional optical device for photographing.

[Explanation of symbols]

Reference numeral 10: optical device for video camera, 11: lens barrel, 11a: outer diameter portion, 11b: flange portion,
11c: filter mounting portion, 12: imaging lens,
12a, 12b: lens, 13: filter, 1
4 ... image sensor, 14a ... chip, 14b ...
Package, 14c: seal glass, 20: chart holding member, 21: chart, 21a: center point, 22: light guide, 23: ultraviolet light source, 24: condensing lens.

Claims (7)

[Claims] 1. An imaging optical system supported in a lens barrel, an optical element disposed behind the imaging optical system, and an imaging element disposed behind the optical element. The optical element has an incident side surface fixed and held integrally to a rear end of the lens barrel, and a surface constituting an incident surface of the imaging element is disposed on an emission side surface of the optical element. An imaging optical device fixed and held by bonding. 2. The image pickup device according to claim 1, wherein the optical axis of the image pickup optical system is adjusted while observing the image pickup screen.
The optical device for photographing according to claim 1, wherein the optical device is adhered to a surface on an emission side of the optical element. 3. The photographing optical device according to claim 1, wherein the optical element is fixed and held to the lens barrel by thermal caulking or bonding. 4. The photographing optical device according to claim 1, wherein the image pickup device is adhered to a surface on an emission side of the optical device with an ultraviolet curable adhesive. 5. The photographing optical device according to claim 4, wherein the curing of the ultraviolet curable adhesive is performed by irradiating ultraviolet rays through an imaging optical system. 6. The curing of the ultraviolet-curable adhesive is performed by irradiating ultraviolet rays through a light guide hole provided on a side surface between the imaging optical system and the optical element of the lens barrel.
The photographing optical device according to claim 4, wherein the photographing is performed. 7. The photographing optical device according to claim 1, wherein a light-shielding film is provided on a peripheral surface of the image sensor after the image sensor is adhered.