JP2000216368A - Infrared-ray cut filter attachment structure of image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance image quality of an image obtained by an image pickup device, without securing space for only the amount of thickness of an infrared- ray cut filter between an image pickup lens, and an image pickup device. SOLUTION: For an infrared-ray filter attachment structure, a plate-shaped solid image pickup element 13 is embedded in the bottom of the recess 12 of a casing 11. A transparent cover glass 15 is set at the step made at the brim of the recess 12 and is bonded by an adhesive. The casing 11 is charged with nitrogen. An infrared cut filter 16 is stuck to the side of the solid-state image pickup element 13 of the cover glass 15, using ultraviolet-ray curing resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared cut filter provided in a digital camera or a video camera, for example, for removing infrared light contained in light incident on an image pickup apparatus.

[0002]

2. Description of the Related Art Conventionally, there is known an apparatus using an image pickup apparatus such as a digital camera in which an infrared cut filter is provided between an image pickup lens and an image pickup apparatus. The infrared cut filter absorbs components in the infrared wavelength range from the light that has passed through the imaging lens, and can improve the image quality of the image obtained by the imaging device. Both surfaces of the infrared cut filter are usually sandwiched between optical low-pass filters, whereby optical disturbance is removed from light passing through the imaging lens and moisture absorption of the infrared cut filter is prevented.

According to the configuration in which the infrared cut filter is provided, a space corresponding to the thickness of the infrared cut filter must be secured between the imaging lens and the imaging device. On the other hand, as a configuration having no space restriction, there is a configuration in which an infrared cut coat is applied to a surface of a cover glass that covers a casing of an imaging device instead of an infrared cut filter. However, the infrared cut coat does not have a problem of hygroscopicity but has an angle dependency, and therefore has a low ability to absorb infrared light with respect to light incident obliquely, and has a sufficient image quality obtained by an imaging device. It is difficult to increase.

[0004]

As described above, according to the conventional configuration, a space corresponding to the thickness of the infrared cut filter is secured between the imaging lens and the imaging device, or the image quality of the image obtained by the imaging device. Had to be sacrificed, and both could not be satisfied.

According to the present invention, there is provided an infrared light source capable of sufficiently improving the image quality of an image obtained by an image pickup device without securing a space between the image pickup lens and the image pickup device by the thickness of the infrared cut filter. It is intended to obtain a cut filter mounting structure.

[0006]

According to the present invention, there is provided an infrared cut filter mounting structure for an image pickup apparatus, wherein a solid-state image pickup device is provided in a casing, a cover glass for covering the solid-state image pickup device is mounted on the casing, and the inside of the casing is provided. In the image pickup apparatus in which the space between the peripheral portion of the cover glass and the casing is sealed so as to shield the cover glass from the outside air, an infrared cut filter is attached to the surface of the cover glass on the solid-state image sensor side.

[0007] The infrared cut filter is preferably affixed to the cover glass with an ultraviolet curable resin. The infrared cut filter is, for example, a flat member smaller than the cover glass. It is preferable that the infrared cut filter is provided in parallel with the solid-state imaging device, and that a gap having substantially the same size as the thickness of the infrared cut filter is formed between the infrared cut filter and the solid-state imaging device.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an imaging device using an infrared cut filter mounting structure.

The casing 11 of the image pickup device has a flat box shape, and has a thin plate-shaped recess 12. A flat solid-state imaging device 13 is embedded in the bottom surface of the concave portion 12. A step 14 is formed on the periphery of the recess 12 so as to surround the entire recess 12. A transparent cover glass 15 is fitted into the step portion 14 and covers the solid-state imaging device 13. The peripheral portion of the cover glass 15 is fixed to the step portion 14 with an adhesive, whereby the space between the peripheral portion of the cover glass 15 and the casing 11 is sealed. That is, the inside of the casing 11 is shut off from the outside air, and nitrogen is sealed in the inside.

An infrared cut filter 16 is attached to a surface of the cover glass 15 on the side of the solid-state imaging device 13. The infrared cut filter 16 is placed on the cover glass 15 in a state where an adhesive made of an ultraviolet curable resin is applied to the entire surface thereof, and the cover glass 1 is irradiated with ultraviolet light.
5 is fixed.

The infrared cut filter 16 is a solid-state image sensor 1
3 is a plate-like member having substantially the same size as the solid-state imaging device 1.
3 in parallel. The surface of the infrared cut filter 16 is slightly smaller than the cover glass 15, and the thickness thereof is about half of the cover glass 15. A gap having substantially the same size as the thickness of the infrared cut filter 16 is formed between the infrared cut filter 16 and the solid-state imaging device 13.

The shape and dimensions of the infrared cut filter 16, the infrared cut filter 16 and the solid-state image sensor 13
Of course, the size of the gap between them can be appropriately changed as necessary.

As described above, in the present embodiment, the infrared cut filter 16 is attached to the back surface of the cover glass 15 of the casing 11 of the imaging apparatus. That is, since the infrared cut filter 16 is disposed in the space formed between the cover glass 15 and the solid-state imaging device 13, there is no need to change the configuration of the solid-state imaging device 13 and the cover glass 15. Further, according to the present embodiment, the space for the thickness of the infrared cut filter between the imaging lens and the imaging device can be reduced, the degree of freedom of the space near the optical axis of the imaging lens increases, and the configuration thereof Is simplified.

Compared with a configuration having an infrared cut coat, the infrared cut filter has no angle dependence, so that infrared light can be efficiently removed from light incident on the solid-state image pickup device 13 and a high quality image can be obtained. Obtainable.

Further, according to the present embodiment, the infrared cut filter 16 is completely sealed and disposed in the concave portion 12 in which nitrogen is sealed, so that there is no possibility of oxidation, and there is no possibility of chemical change due to moisture absorption. For this reason, performance degradation does not occur.

[0016]

As described above, according to the present invention, it is not necessary to secure a space corresponding to the thickness of the infrared cut filter between the imaging lens and the imaging device, so that the configuration around the optical axis of the imaging lens is reduced. Simplification can be achieved and performance can be maintained for a long time. Furthermore, according to the present invention, it is possible to sufficiently improve the image quality of an image obtained by the imaging device as compared with the configuration in which the infrared cut coat is provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing an imaging apparatus using an infrared cut filter mounting structure according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

[Explanation of symbols]

 Reference Signs List 11 casing 12 recess 13 solid-state imaging device 14 step 15 cover glass 16 infrared cut filter

Claims (5)

[Claims] 1. A solid-state imaging device is provided in a casing, a cover glass for covering the solid-state imaging device is attached to the casing, and a peripheral portion of the cover glass and a casing are separated from each other so that the inside of the casing is shielded from outside air. An infrared cut filter mounting structure for an image pickup device, wherein an infrared cut filter is attached to a surface of the cover glass on the solid-state image pickup device side in a sealed image pickup device. 2. The infrared cut filter mounting structure according to claim 1, wherein said infrared cut filter is affixed to a cover glass with an ultraviolet curable resin. 3. The infrared cut filter mounting structure according to claim 1, wherein the infrared cut filter is a flat member smaller than the cover glass. 4. The infrared cut filter mounting structure according to claim 1, wherein the infrared cut filter is provided in parallel with the solid-state imaging device. 5. The infrared cut filter according to claim 4, wherein a gap having substantially the same size as the thickness of the infrared cut filter is formed between the infrared cut filter and the solid-state imaging device. Filter mounting structure.