Camera unit and endoscope

Abstract

A camera unit (1) has a three-dimensional wiring board (10) having a recess (H10), a stacked element (30) housed in the recess (H10) including a camera element (34) and a plurality of optical members (31, 32), and a sealing resin (20) filling a gap between the recess (H10) and the stacked element (30), the plurality of optical members (31, 32) including a composite element in which a first optical member (31A, 32A) is provided with a second optical member (31B, 32B), the second optical member (31B, 32B) having an elastic modulus smaller than the elastic modulus of the first optical member (31A, 32A) and the elastic modulus of the camera element (34) and greater than or equal to the elastic modulus of the sealing resin (20), the sealing resin (20) having a thermal expansion rate greater than the thermal expansion rate of the first optical member (31A, 32A) and the thermal expansion rate of the camera element (34) and smaller than the thermal expansion rate of the second optical member (31B, 32B).

Description

Technical Field

[0001] The present invention relates to a camera unit comprising stacked elements and an endoscope having a camera unit comprising stacked elements disposed at the front end. Background Technology

[0002] To reduce invasiveness, it is important to reduce the diameter of the camera unit located at the front end of the insertion section of the endoscope.

[0003] Japanese Patent Application Publication No. 2012-18993 discloses a laminated element capable of efficiently manufacturing camera units with small diameters. The laminated element is manufactured by bonding multiple lens wafers, each containing multiple lenses, and multiple camera elements together with resin and then cutting them.

[0004] International Publication No. 2015 / 082328 (Japanese Patent No. 6533787) discloses a camera unit in which stacked elements are housed in a slot of a MID.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-18993

[0008] Patent Document 2: International Publication No. 2015 / 082328 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] A stacked element consists of multiple elements with different coefficients of thermal expansion. Therefore, when temperature changes occur, the stacked element may sometimes be damaged by thermal stress, and sometimes the reliability of the camera unit equipped with the stacked element may be reduced.

[0011] The purpose of the embodiments of the present invention is to provide a camera unit and an endoscope with excellent reliability.

[0012] means for solving problems

[0013] The camera unit according to an embodiment of the present invention includes: a three-dimensional wiring board having a recess; a stacked element housed in the recess, including a camera element and a plurality of optical elements; and a sealing resin filling the gap between the recess and the stacked element, wherein the plurality of optical elements includes a composite element in which a second optical element is disposed on a first optical element, the elastic modulus of the second optical element being less than the elastic modulus of the first optical element and the elastic modulus of the camera element, and greater than or equal to the elastic modulus of the sealing resin, and the thermal expansion coefficient of the sealing resin being greater than the thermal expansion coefficient of the first optical element and the thermal expansion coefficient of the camera element, and less than the thermal expansion coefficient of the second optical element.

[0014] Another embodiment of the endoscope includes a camera unit comprising: a three-dimensional wiring board having a recess; a stacked element housed in the recess, including a camera element and a plurality of optical elements; and a sealing resin filling the gap between the recess and the stacked element, wherein the plurality of optical elements includes a composite element in which a second optical element is disposed on a first optical element, the elastic modulus of the second optical element being less than the elastic modulus of the first optical element and the elastic modulus of the camera element, and greater than or equal to the elastic modulus of the sealing resin, and the thermal expansion coefficient of the sealing resin being greater than the thermal expansion coefficient of the first optical element and the thermal expansion coefficient of the camera element, and less than the thermal expansion coefficient of the second optical element.

[0015] Invention Effects

[0016] According to embodiments of the present invention, a camera unit with excellent reliability and an endoscope with excellent reliability can be provided. Attached Figure Description

[0017] Figure 1 This is a perspective view of the camera unit according to the first embodiment.

[0018] Figure 2 It is along Figure 1 A cross-sectional view of line II-II.

[0019] Figure 3 This is a cross-sectional view of the camera unit of Modified Example 1 of the first embodiment.

[0020] Figure 4 This is a three-dimensional view of the endoscope according to the second embodiment. Detailed Implementation

[0021] <First Implementation Method>

[0022] like Figure 1 and Figure 2 As shown, the camera unit 1 of this embodiment has a three-dimensional wiring board 10, a sealing resin 20, and a stacked element 30.

[0023] Furthermore, the accompanying drawings based on the embodiments are schematic. The relationship between the thickness and width of each part, the ratio of the thickness of each part, etc., differ from the actual figures. The drawings also include the dimensional relationships between each other and parts with different ratios. Sometimes, illustrations of some constituent elements and annotations of the figures are omitted. The direction of light incidence is referred to as "up".

[0024] The three-dimensional wiring board 10 is a non-planar wiring board, such as a molded interconnect device (MID), having a bottomed recess (cavity) H10 with an opening on its upper surface 10SA. The stacked element 30 housed in the recess H10 is composed of multiple optical elements 31, 32, and 33 constituting an optical system and an imaging element (image sensor) 34 serving as an imaging component. Sealing resin 20 fills the gap between the recess H10 and the stacked element 30.

[0025] Optical element 31 is a hybrid lens element (composite element) having a glass plate as a first optical component 31A and a resin lens as a second optical component 31B disposed on the lower surface of the first optical component 31A. Optical element 32 is a hybrid lens element having a glass plate as a first optical component 32A and a resin lens as a second optical component 32B disposed on the lower surface of the first optical component 32A. Optical element 33 is a glass plate, such as an infrared cutoff filter element made of glass that blocks infrared radiation.

[0026] Furthermore, in the cross-sectional view, the optical elements of the stacked element 30 are shown as flat plates. Additionally, the adhesive layer that bonds the stacked optical elements together is thin, and its effect on thermal stress is negligible, therefore it is not shown.

[0027] Hybrid lens elements are manufactured by placing a resin lens / resin spacer on a glass plate. For example, uncured liquid or gel-like transparent UV-curable resin is placed on a glass plate, and UV light is used to cure the resin while pressing it against a mold with a recessed area having a specified inner surface shape. Regarding the outer surface shape of the resin lens, since the inner surface shape of the mold is transferred, even aspherical lenses can be easily manufactured.

[0028] The first optical components 31A and 32A and the optical element 33 are, for example, borosilicate glass, quartz glass, or sapphire glass. The second optical components 31B and 32B and the sealing resin 20 are, for example, silicone resin, epoxy resin, or acrylic resin.

[0029] The base material of the three-dimensional wiring board 10 is a non-conductive resin, especially an engineering plastic that can be molded. The base material is, for example, composed of PA (polyamide), PC (polycarbonate), LCP (liquid crystal polymer), PEEK (polyether ether ketone), nylon, PPA (polyphthalamide), ABS (acrylonitrile / butadiene / styrene), or a composite resin incorporating inorganic fillers into these resins.

[0030] Furthermore, the structure of the optical system, i.e., the structure (thickness, shape), type, quantity, and stacking order of the optical elements (first optical component / second optical component), can be varied according to specifications. For example, the first and second optical components can be arranged without alternation. A patterned light-shielding film can be provided as an aperture on the main surface of the optical element. In addition, the shape of the imaging unit 1 is cylindrical, but it can also be prismatic or a combination of these shapes.

[0031] The image sensor 34, which uses silicon as its base material, has a light-receiving part composed of a CCD or the like. The image sensor 34 receives drive signals and transmits image signals through solder 39 on its lower surface and through-hole wiring 19 of the three-dimensional wiring board 10.

[0032] In addition, the camera component may have a semiconductor element for processing the camera signal stacked on the lower surface of the camera element 34, or a glass cover may be provided on the upper surface of the camera element 34.

[0033] The sealing resin 20 fills the gap between the wall of the recess H10 of the three-dimensional wiring board 10 and the side surface of the laminated element 30. While sealing the side surface of the laminated element 30, the sealing resin 20 also alleviates the stress generated in the laminated element 30, as described later.

[0034] To mitigate the stress generated in the laminated element 30, it is preferable that the width of the gap, or in other words, the thickness D of the sealing resin 20, has a thickness exceeding a predetermined thickness. Therefore, the width of the gap is preferably, for example, 100 μm to 800 μm.

[0035] It should be noted that, in order to prevent external light from entering from the side of the laminated element 30, the sealing resin 20 preferably has light-shielding properties by containing light-shielding particles, etc.

[0036] As shown in Table 1 below, the elastic modulus E and the coefficient of thermal expansion α of the multiple components of the stacked elements 30 of the camera unit 1 meet the specified conditions. The elastic modulus E is the tensile elastic modulus (25°C) measured according to JIS K7113. The coefficient of thermal expansion is the linear expansion measured according to JIS K7197, JIS R3251, and JIS Z2285.

[0037] [Table 1]

[0038]

[0039] That is, the elastic modulus E2 of the resin used as the second optical components 31B and 32B is less than the elastic modulus E1 of the glass plate used as the first optical component and the elastic modulus E3 of the imaging element 34, and is greater than or equal to the elastic modulus E4 of the sealing resin 20. Furthermore, the thermal expansion coefficient α4 of the sealing resin 20 is greater than the thermal expansion coefficient α1 of the glass plates 31A and 32A used as the first optical components, the glass plate 33 used as the optical element, and the thermal expansion coefficient α3 of the imaging element 34, and is less than the thermal expansion coefficient α2 of the resin lenses 31B and 32B used as the second optical components.

[0040] For example, the coefficient of thermal expansion α1 is 5ppm / K to 10ppm / K, and the elastic modulus E1 is 70GPa to 100GPa. The coefficient of thermal expansion α2 is 60ppm / K to 100ppm / K, and the elastic modulus E2 is 2.6GPa to 10GPa. Additionally, for example, "X1~X2" means "greater than X1 and less than X2".

[0041] Furthermore, the thermal expansion coefficient α of the PEEK resin used as the base material for the three-dimensional wiring board 10 is 18ppm / K to 26ppm / K, and the elastic modulus E is 10GPa to 20GPa. The thermal expansion coefficient α of the solder 39 is 20ppm / K to 30ppm / K, and the elastic modulus E is 50GPa to 100GPa.

[0042] In the camera unit 1, the gap between the stacked element 30 and the three-dimensional wiring board 10 is filled with sealing resin 20. Therefore, when mechanical loads such as impacts are applied to the camera unit 1, the sealing resin 20 is also subjected to load, thus mitigating the stress on the stacked element 30.

[0043] Furthermore, when temperature changes occur in the imaging unit 1 due to external temperature variations and driving, the thermal expansion rates of the first optical components 31A, 32A, the second optical components 31B, 32B, and the imaging element 34 in the stacked elements 30 differ, thus generating thermal strain. However, in the imaging unit 1, the sealing resin 20, whose elastic modulus is smaller than that of the stacked elements 30 (first optical components 31A, 32A, second optical components 31B, 32B, and imaging element 34), deforms and absorbs stress, thereby mitigating the stress generated in the stacked elements 30.

[0044] To protect the laminated elements 30, the sealing resin 20 preferably has a thermal expansion coefficient α4 of 45ppm / K to 80ppm / K and an elastic modulus E4 of 1.0GPa to 2.5GPa.

[0045] It should be noted that when the occupancy rate (total thickness in the optical axis direction) of the first optical component in the stacked element 30 is less than that of the second optical component, the strain caused by thermal expansion is small, which is therefore preferred.

[0046] <Modifications of the First Embodiment>

[0047] Figure 3 The camera unit 1A in the modified example shown is similar to camera unit 1 and has the same effect. Therefore, structural elements with the same function are labeled with the same number and the description is omitted.

[0048] In the stacked element 30A of the camera unit 1A, the optical element 32 is a hybrid lens element having a glass plate as a first optical component 32A, a resin lens as a second optical component 32C disposed on the upper surface of the first optical component 32A, and a resin lens and a resin spacer as a second optical component 32B disposed on the lower surface of the first optical component 32A.

[0049] In the imaging unit 1A, the area of ​​the opening of the recess H10A in the three-dimensional wiring board 10A is larger than the area of ​​the bottom surface. That is, the wall surface of the recess H10A is not perpendicular to the upper surface 10SA, but is inclined. As described above, when a temperature change occurs in the imaging unit due to external temperature changes and driving, thermal strain is generated in the stacked elements. In the stacked elements, the strain generated in each stacked optical component accumulates. Since the lower imaging element 34 is fixed to the bottom surface of the recess H10, the thermal strain is greater towards the top of the stacked elements.

[0050] The thicker the sealing resin 20, the greater the stress mitigation effect caused by the deformation of the sealing resin 20 with its low elastic modulus. In the camera unit 1A, the cross-sectional area of ​​the recess H10A of the three-dimensional wiring board 10A increases as it approaches the opening from the bottom surface; therefore, the thickness D of the sealing resin 20 also increases as it approaches the opening from the bottom surface. The thickness D of the sealing resin varies according to the magnitude of thermal strain, thus the reliability of the camera unit 1A is higher than that of the camera unit 1.

[0051] The tilt angle θ of the wall surface of the recess H10A is preferably greater than 1 degree and less than approximately 5 degrees. If the tilt angle θ exceeds this range, the stress relief effect of the sealing resin 20 is significant. If the tilt angle θ is less than the above range, the increase in the dimension of the camera unit in the orthogonal direction of the optical axis is smaller.

[0052] <Second Implementation Method>

[0053] Figure 4 The endoscope 9 of this embodiment shown includes an insertion part 91, an operation part 92, a universal cable 93, and an endoscope connector 94.

[0054] The slender, tubular insertion part 91 is inserted into the body cavity of the organism. The insertion part 91 is provided with a front end 91A, a curved part 91B, and a flexible tube 91C in sequence from the front end side, and is flexible as a whole.

[0055] The front end 91A has a rigid component 91A1, which internally contains various units. These various units include camera units 1 and 1A, a device insertion channel, an illumination unit, etc.

[0056] The bending section 91B bends in the up, down, left, and right directions according to the rotation operation of the bending knob of the operation section 92 for performing the bending operation.

[0057] The flexible tube 91C is a passively flexible tubular component. A treatment device insertion channel, various electrical signal lines, and an optical fiber bundle are inserted through the flexible tube 91C. The electrical signal lines extend from the camera unit built into the front end 91A and are routed to the universal cable 93 via the operation section 92. The optical fiber bundle guides light from the light source device, which is an external device, to the front end face of the front end 91A.

[0058] The operating section 92 and the base end of the insertion section 91 are continuously provided, and multiple operating components are included. The universal cable 93 is flexible and is a tubular component extending from the operating section 92. The endoscope connector 94 is a connecting component for connecting the universal cable 93 to an external device.

[0059] The endoscope 9 has imaging units 1 and 1A disposed at the front end 91A of the insertion section 91. As already explained, the imaging units 1 and 1A have high reliability, therefore the endoscope 9 has high reliability.

[0060] Endoscopes can be either flexible or rigid, with a flexible insertion section. Furthermore, endoscopes can be used for medical or industrial purposes.

[0061] This invention is not limited to the embodiments described above, and various modifications, combinations, and applications can be made without departing from the spirit of the invention.

[0062] Label Explanation

[0063] 1. 1A··· Camera Unit

[0064] 9. Endoscopy

[0065] 10. 3D wiring board

[0066] 19··· Through-hole wiring

[0067] 20··· Sealing resin

[0068] 30···Layered Components

[0069] 31, 32, 33... Optical elements

[0070] 31A, 32A... First optical component

[0071] 31B, 32B... Second optical components

[0072] 34···Camera Components

[0073] 39··· Solder

Claims

1. A camera unit, characterized in that, The camera unit has: A three-dimensional wiring board with recesses; A stacked element, housed within the recess, includes a camera element and multiple optical elements; and A sealing resin that fills the gap between the recess and the laminated element. The plurality of optical elements includes a composite element in which a second optical element is disposed on a first optical component. The elastic modulus of the second optical component is less than that of the first optical component and the imaging element, and greater than or equal to that of the sealing resin. The thermal expansion coefficient of the sealing resin is greater than that of the first optical component and the imaging element, but less than that of the second optical component. The thickness of the sealing resin increases as it approaches the opening from the bottom surface of the recess.

2. The camera unit according to claim 1, characterized in that, The occupancy rate of the first optical component in the stacked element is less than that of the second optical component.

3. The camera unit according to claim 1, characterized in that, The sealing resin has a thermal expansion coefficient of 45ppm / K to 80ppm / K and an elastic modulus of 1.0GPa to 2.5GPa.

4. The camera unit according to claim 1, characterized in that, The sealing resin has light-shielding properties.

5. The camera unit according to claim 1, characterized in that, The first optical component is a glass plate. The second optical component is a resin lens. The composite element is a hybrid lens element.

6. An endoscope, characterized in that, The endoscope includes a camera unit at the front end of the insertion section. The camera unit has: A three-dimensional wiring board with recesses; A stacked element, housed within the recess, includes a camera element and multiple optical elements; and A sealing resin that fills the gap between the recess and the laminated element. The plurality of optical elements includes a composite element in which a second optical element is disposed on a first optical component. The elastic modulus of the second optical component is less than that of the first optical component and the imaging element, and greater than or equal to that of the sealing resin. The thermal expansion coefficient of the sealing resin is greater than that of the first optical component and the imaging element, but less than that of the second optical component. The thickness of the sealing resin increases as it approaches the opening from the bottom surface of the recess.

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