JP5210127B2 - Imaging device - Google Patents

Description

  The present invention relates to an image pickup apparatus used for a video camera or the like, and relates to a small image pickup apparatus mainly used for an endoscope apparatus.

  2. Description of the Related Art In recent years, endoscope apparatuses that incorporate a small imaging device and display a subject image taken by a monitor or the like have become mainstream. In such a small image pickup apparatus, since the assembly accuracy of each component is required, an ultraviolet curable adhesive having a short curing time is used.

  For example, Patent Document 1 discloses that a connecting and fixing member on which an optical multilayer film that precisely adjusts the position of a color separation optical prism and a solid-state imaging device is transmitted through ultraviolet rays that cure an ultraviolet curable adhesive, and visible light. And an imaging device formed of a member that absorbs infrared rays.

  Further, for example, Patent Document 2 discloses an electronic device provided with an imaging device provided with a multilayer interference filter capable of transmitting ultraviolet light on an incident surface on which an optical image of a quartz filter bonded with a prism and an ultraviolet curable adhesive is incident. An endoscope apparatus is disclosed.

For example, in Patent Document 3, ultraviolet rays emitted from a high-pressure mercury lamp pass through the final optical component to cure the adhesive layer of the ultraviolet curable adhesive, and finally bond the final optical component to the sealing glass. A manufacturing method of an imaging unit that constitutes a joint unit in which an optical component and a solid-state imaging device are integrated is disclosed. In this prior art, a method is disclosed in which a long wavelength cut filter is used as an interference film in the subsequent stage of a high-pressure mercury lamp in order to irradiate ultraviolet rays having a bright line in a predetermined wavelength band or less.
JP-A-5-37943 JP 9-262207 A JP 2006-93925 A

  By the way, in order to prevent lens flare (halation), the imaging apparatus is provided with a flare stop for cutting harmful rays. This flare stop is preferably provided at a position as close as possible to the solid-state imaging device. For this reason, in the conventional imaging apparatus, there are cases where the optical component on which the flare stop is formed is directly attached to the surface of the protective cover glass provided on the light receiving surface of the solid-state imaging device.

  However, when an ultraviolet curable adhesive as described in Patent Document 1 to Patent Document 3 is used at the time of joining the surface side on which the flare diaphragm of the optical component is formed and the cover glass surface of the solid-state image sensor, However, there is a problem that ultraviolet light is not blocked, unevenness occurs in adhesion between the optical component and the cover glass, and sufficient adhesive strength cannot be obtained. For this reason, the optical component and the cover glass cannot obtain sufficient adhesive strength, and thus may be peeled off.

  In addition, since the imaging apparatus of patent document 1 is a structure which adjusts the position of a color separation optical prism and a solid-state image sensor with the connection fixing member in which the optical multilayer film was formed, there also exists a problem that an external shape enlarges.

  Therefore, the present invention has been made in view of the above-mentioned circumstances, and the object of the present invention is to dispose a diaphragm for cutting harmful rays in the vicinity of the solid-state imaging device, suitably preventing lens flare, An object of the present invention is to provide an imaging device having sufficient adhesive strength between optical components.

In order to achieve the above object, an imaging device according to one embodiment of the present invention includes an imaging element having a light receiving surface that detects light of a subject image, a cover glass provided in front of the light receiving surface, and a surface of the cover glass. And an optical member whose base end face is bonded directly by bonding, and an aperture filter formed by depositing an interference filter that shields visible light on the base end face of the optical member located closest to the image sensor. And .

  According to the present invention, an aperture that cuts harmful rays is arranged in the vicinity of a solid-state image sensor, and it is possible to realize an imaging apparatus that suitably prevents lens flare and has sufficient adhesive strength between optical components. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the imaging apparatus according to the first embodiment will be described below with reference to FIGS. In the following, for the sake of simplicity of explanation, only the main part of the imaging apparatus is illustrated and the details of the main part will be described. 1 to 4 relate to the first embodiment of the present invention, FIG. 1 is a cross-sectional view showing the main part of the imaging apparatus, FIG. 2 is a plan view taken along the arrow II in FIG. 1, and FIG. -III sectional view, FIG. 4 is a partial sectional view showing the main part of an imaging apparatus of a modification.

As shown in FIG. 1 and FIG. 2, the imaging device 1 of the present embodiment is a small imaging means used for an endoscope or the like, and is provided in the solid-state imaging device unit 2 at the most proximal end of the lens unit. The optical member 3 which is the obtained glass plate is joined.
The solid-state image pickup device unit 2 covers a front surface of a solid-state image pickup device 4 such as a CCD and an image area 5 which is an image sensor serving as a light receiving surface of the solid-state image pickup device 4. Here, the cover glass is a rectangular glass plate. 6 and a TAB (tape automated bonding) tape 7 bump-connected to the solid-state imaging device 4.

  The optical member 3 has a cylindrical shape, and transmits light of a subject image on the photographing optical axis O shown in the drawing, which is collected by an objective lens (not shown) disposed in front. The optical member 3 is provided with an interference filter 8 on one surface (bonding surface) on the base end surface side to be bonded to the cover glass 6.

  As shown in FIGS. 2 and 3, the interference filter 8 is a very thin film formed by vapor deposition on the edge of one surface of the optical member 3 which is masked in a rectangular shape, here an octagon in the center. . That is, the optical member 3 is formed with a non-film region 10 where the interference filter 8 having an octagonal central portion on one surface is not deposited. Note that the octagonal masking process of the optical member 3 is removed after the interference filter 8 is formed.

  The interference filter 8 is a multilayer interference formed by laminating an interference film that transmits only ultraviolet light in the wavelength band of 300 to 380 nm and absorbs (reflects) visible light, infrared light, and the like, which are wavelength bands other than ultraviolet light. It is a membrane light filter. That is, in the imaging apparatus 1 of the present embodiment, the interference filter 8 of the optical member 3 does not transmit visible light, and thus is harmful to the light of the subject image on the imaging optical axis O detected in the image area 5 of the solid-state imaging device 4. A flare stop that blocks (cuts) light rays is formed.

  At the time of assembling the lens unit and the solid-state image sensor unit 2, first, in a state where the optical member 3 is centered with respect to the image area 5 of the solid-state image sensor 4, the base end surface on which the interference filter 8 of the optical member 3 is formed The joint surface between the one surface and the surface of the cover glass 6 is bonded and fixed by the ultraviolet curable adhesive 9.

  At this time, ultraviolet light (light having a wavelength band of 300 to 380 nm) is irradiated from the other surface side that is the tip surface of the optical member 3. The ultraviolet light is not absorbed (reflected) by the interference filter 8 formed on the optical member 3, but is spread on the base end surface of the optical member 3 and the entire surface of the cover glass 6 where the ultraviolet curable adhesive 9 is interposed. Irradiated. Therefore, the ultraviolet curable adhesive 9 is quickly and uniformly cured.

  The imaging apparatus 1 of the present embodiment configured as described above is formed by forming the interference filter 8 that transmits only ultraviolet light on the optical member 3 provided at the most proximal end of the lens unit by vapor deposition. 8 constitutes a flare stop, and the ultraviolet curable adhesive 9 that adheres the optical member 3 and the cover glass 6 provided at the forefront of the solid-state imaging device unit 2 can be reliably cured.

  Moreover, since the imaging device 1 can form an interference filter 8 serving as a flare stop at the proximal end of the optical member 3 located closest to the solid-state imaging device unit 2, it has a suitable anti-flare effect. It becomes the composition.

As described above, the image pickup apparatus 1 according to the present embodiment arranges the interference filter 8 serving as a diaphragm for shielding (cutting) harmful rays, in the vicinity of the solid-state image pickup device 4, and appropriately prevents lens flare. It can be set as the structure fully equipped with the adhesive strength between optical components. The objective lens (group) constituting the objective optical system of the lens unit is conventionally configured to shield (cut) the ultraviolet light of normal light, so that there is almost no light including ultraviolet light that passes through the interference filter 8. There is no influence of harmful rays on the subject image detected by the solid-state image sensor unit 2.
Furthermore, since the imaging device 1 has a configuration in which the optical member 3 is directly bonded to the cover glass 6, there is no need to provide a holding frame for joining them, and an increase in size of the outer shape is prevented.

  When the non-film region 10 is smaller than the image area 5, it is difficult to align the two in visible light observation, but the positional relationship between the two can be grasped by switching between ultraviolet light and visible light. That is, the bonding position of the optical member 3 and the cover glass 6 can be easily adjusted.

  Moreover, when the ultraviolet adhesive 9 is applied to the surface of the cover glass 6, it is preferable to observe in a wavelength region where the ultraviolet adhesive 9 is not cured among 300 to 380 nm. If the optical member 3 and the image area 5 of the solid-state image sensor 4 are simply centered, the interference filter 8 is configured to transmit only infrared light, for example. And the image area 5 can be easily aligned.

As shown in FIG. 4, the imaging apparatus 1 may further include an optical member 11 that is a glass plate in which an interference filter 12 that forms a flare stop is formed on the base end surface.
Specifically, the interference filter 12 of the optical member 11 transmits only ultraviolet light having a wavelength band of 300 to 380 nm and visible light, infrared light, and the like having a wavelength band other than ultraviolet light, similar to the interference filter 8 described above. Is a multilayer interference film optical filter formed by stacking interference films that absorb (reflect) light.

  In the optical member 11, the base end surface on which the interference filter 12 is formed and the distal end surface of the optical member 3 are bonded by the ultraviolet curable adhesive 9. The ultraviolet light for curing the ultraviolet curable adhesive 9 is formed by the interference filter 8 of the optical member 3 in a state of being centered with respect to the two optical members 3 and 11 and the image area 5 of the solid-state imaging device 4. Irradiation is performed so as to collectively bond and fix the one end surface that is the base end surface, the surface of the cover glass 6, the base end surface of the optical member 11 on which the interference filter 12 is formed, and the front end surface of the optical member 3.

  As described above, when two flare stops are provided in the imaging apparatus 1, the optical member 11 on which the interference filter 12 is formed can be bonded with the ultraviolet curable adhesive 9. The optical members 3 and 11 and the cover glass 6 of the solid-state imaging device 4 are joined with stable adhesive strength.

(Second Embodiment)
Next, an imaging apparatus according to the second embodiment will be described below with reference to FIGS. 5 to 7 relate to the second embodiment of the present invention, FIG. 5 is a cross-sectional view showing the main part of the imaging apparatus, FIG. 6 is a cross-sectional view taken along VI-VI in FIG. 5, and FIG. 5 is a sectional view taken along line VII-VII in FIG. In the following description, the same components as those of the imaging device 1 of the first embodiment are denoted by the same reference numerals, and the description of the configurations and the operational effects is omitted.

As shown in FIGS. 5 to 7, the imaging apparatus 20 according to the present embodiment includes a reflecting surface 23 that refracts a subject image on the photographing optical axis O and totally changes the direction of light of the subject image. The prism 21 is provided.
The prism 21 is formed by joining the incident surface 24 on which the subject image on the photographing optical axis O is incident and the base end surface of the objective lens 22, and the exit surface 25 on which the subject image reflected by the reflecting surface 23 is emitted and the solid-state imaging device unit 2. The surface of the cover glass 6 is joined.

  As in the first embodiment, the incident surface 24 of the prism 21 transmits only ultraviolet light having a wavelength band of 300 to 380 nm and absorbs (reflects) visible light, infrared light, and the like, which are wavelength bands other than ultraviolet light. The interference filter 26 is a multilayer interference film optical filter formed by stacking interference films.

  As shown in FIG. 6, the interference filter 26 is a very thin film that is masked in the center of the incident surface 24, here circularly, and is deposited on the edge of the incident surface 24. In other words, the non-film region 28 in which the interference filter 26 having a circular central portion is not formed by vapor deposition is formed on the incident surface 24.

  Similarly to the first embodiment, the emission surface 25 of the prism 21 transmits only ultraviolet light having a wavelength band of 300 to 380 nm and absorbs visible light, infrared light, and the like, which are wavelength bands other than ultraviolet light. It has an interference filter 27 which is a multilayer interference film optical filter formed by stacking (reflecting) interference films.

As shown in FIG. 7, the interference filter 27 is a very thin film that is subjected to a masking process in the center of the emission surface 25 in a rectangular shape, here an octagonal shape, and is deposited on the edge of the emission surface 25. It is. That is, a non-film region 29 in which the interference filter 27 having an octagonal central portion is not formed on the emission surface 25 is formed.
Also in this case, the masking processes for the incident surface 24 and the exit surface 25 of the prism 21 are removed after the formation of the interference filters 26 and 27.

  That is, also in the imaging device 20 of the present embodiment, the interference filters 26 and 27 deposited on the incident surface 24 and the emission surface 25 of the prism 21 do not transmit visible light. A flare stop that blocks (cuts) harmful light in the light of the subject image on the photographing optical axis O detected in the area 5 is configured.

  When the objective lens 22, the prism 21, and the solid-state image sensor unit 2 are assembled, first, the objective lens 22 and the prism 21 are centered with respect to the image area 5 of the solid-state image sensor 4. Then, the entrance surface 24 on which the interference filter 26 is formed, the base end surface of the objective lens 22, and the joint surfaces of the exit surface 25 on which the interference filter 27 is formed and the surface of the cover glass 6 are bonded by the ultraviolet curable adhesive 9. Fixed.

  At this time, ultraviolet light (light having a wavelength band of 300 to 380 nm) is irradiated from the objective lens 22 side. The ultraviolet light is not absorbed (reflected) by the interference filters 26 and 27 formed on the prism 21, and the incident surface 24 on which the interference filter 26 with the ultraviolet curable adhesive 9 is formed and the objective lens 22. And the entire area of each joint surface between the emission surface 25 on which the interference filter 27 is formed and the surface of the cover glass 6 are irradiated. Therefore, the ultraviolet curable adhesive 9 is quickly and uniformly cured.

  In the imaging apparatus 20 of the present embodiment configured as described above, interference filters 26 and 27 that transmit only ultraviolet light are formed on the entrance surface 24 and the exit surface 25 of the prism 21 by vapor deposition, so that these interferences can be obtained. The filters 26 and 27 constitute a flare stop, and the entrance surface 24 on which the interference filters 26 and 27 are formed, the exit surface 25, the objective lens 22, and the ultraviolet curable adhesive 9 for bonding the cover glass 6. Can be cured stably and reliably.

  Similarly to the first embodiment, the imaging device 20 can also form an interference filter 27 serving as a flare stop on the prism 21 located closest to the solid-state imaging device unit 2. It is the structure provided with the suitable flare prevention effect.

  The invention described in each of the above-described embodiments is not limited to the embodiments and modifications, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if several constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem to be solved by the invention can be solved, and the effect described in the effect of the invention can be obtained. A configuration from which this configuration requirement is deleted can be extracted as an invention.

Sectional drawing which shows the principal part of the imaging device which concerns on the 1st Embodiment of this invention Same as the arrow II in FIG. Fig. 3 is a sectional view taken along line III-III in Fig. The same fragmentary sectional view which shows the principal part of the imaging device of the modification Sectional drawing which shows the principal part of the imaging device which concerns on the 2nd Embodiment of this invention. FIG. 5 is a sectional view taken along line VI-VI in FIG. VII-VII sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Imaging device 2 ... Solid-state image sensor unit 3 ... Optical member 4 ... Solid-state image sensor 5 ... Image area 6 ... Cover glass 7 ... TAB tape 8 ... Interference filter 9 ... Ultraviolet curable adhesive 10 ... Non-film | membrane area | region O ... Photographing optical axis

Claims (3)

An image sensor having a light receiving surface for detecting light of a subject image;
A cover glass provided in front of the light receiving surface;
An optical member whose base end face is directly bonded to the surface of the cover glass by bonding;
A diaphragm formed by vapor-depositing an interference filter that shields visible light on the base end face of the optical member located closest to the imaging element ;
An imaging apparatus comprising: The diaphragm is formed by the interference filter as a multilayer interference film optical filter in which an interference film that transmits only the wavelength band of ultraviolet light is laminated ,
The optical member and the cover glass are bonded with an ultraviolet curable adhesive,
The imaging apparatus according to claim 1.   The imaging apparatus according to claim 1, wherein the diaphragm is formed on a joint surface that is joined to a surface of the cover glass of the optical member.

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