JP2024057687A - Electronics - Google Patents

Abstract

[Problem] To provide an electronic device capable of suppressing flange back change caused by heat during shooting while eliminating individual variation in flange back correction amount. [Solution] The electronic device 10 has a base member 400 capable of holding an imaging optical system, a fixed member 250 fixed to the base member, a holding member 220 holding an imaging element and supported by the fixed member, biasing members 224, 254 for biasing the holding member toward the fixed member, an adjustment member 500 for adjusting the inclination of the imaging surface with respect to the base member, and thermal expansion members 261-263 disposed between the fixed member and the holding member and disposed in holes 221-223 formed in the holding member and having a linear expansion coefficient larger than that of the holding member, the thermal expansion members including tapered first surfaces 261a-263a formed on the holding member side and second surfaces 261b-263b, 261g-263g formed on the fixed member side and parallel to a plane perpendicular to the optical axis of the imaging optical system. [Selected Figure] FIG.

Description

The present invention relates to electronic devices that use image sensors to capture images of subjects, and in particular to the retention reliability of image sensor units.

In recent years, as the number of pixels in the image sensors used in imaging devices has increased, high precision is required for the distance and inclination of the flange back of the imaging device. Here, the flange back refers to the distance from the mount surface of the imaging device body to which the lens barrel is attached to the imaging device. When shooting video, heat generated by the imaging device causes thermal expansion of the housing of the imaging device, deforming the unit including the imaging device, and changing the flange back.

Patent document 1 discloses an imaging device in which a bimetal member is installed between a lens holding member and an imaging element holding member.

Japanese Patent Application Laid-Open No. 07-058909

However, in the conventional technology disclosed in Patent Document 1, it is necessary to adjust the height of the bimetal member in the optical axis direction during initial flange back adjustment. The amount of thermal deformation of the bimetal member varies depending on the shape and dimensions. For this reason, there is a concern that variation in the flange back correction amount will occur in individual imaging devices.

The present invention provides an electronic device that can suppress changes in flange back caused by heat during shooting while eliminating individual variations in the amount of flange back correction.

According to one aspect of the present invention, there is provided an electronic device comprising: a base member capable of holding an imaging optical system;
The imaging optical system includes a fixed member fixed to the base member, a holding member that holds an imaging element and is supported against the fixed member, a biasing member that biases the holding member toward the fixed member, an adjustment member that adjusts the inclination of the imaging surface of the imaging element relative to the base member, and a thermal expansion member that is disposed between the fixed member and the holding member and in a hole formed in the holding member and has a larger linear expansion coefficient than the holding member, wherein the thermal expansion member includes a tapered first surface formed on the holding member side and a second surface formed on the fixed member side and parallel to a plane perpendicular to the optical axis of the imaging optical system.

Other objects and features of the present invention are described in the following examples.

The present invention provides an electronic device that can suppress changes in flange back caused by heat during shooting while eliminating individual variations in the amount of flange back correction.

FIG. 1 is a perspective view of an electronic device. 2 is an exploded perspective view of the main part of the electronic device as seen from the rear side. FIG. FIG. 2 is an exploded perspective view of the image sensor unit according to the first embodiment. 4 is an exploded perspective view showing the image sensor unit according to the first embodiment, viewed from a different direction than FIG. 3. 1A is a front view of an image sensor unit according to a first embodiment, and FIG. 1B is a cross-sectional view of the periphery of a thermal expansion member. 10A to 10C are diagrams illustrating a method for deriving the optimal shape of a thermal expansion member. 4 is a schematic diagram showing temperature deformation of a thermal expansion member. FIG. 13A is a front view of an image sensor unit according to a second embodiment, and FIG. 13B is a cross-sectional view of the periphery of a thermal expansion member. 13A is a front view of an image sensor unit according to a third embodiment, and FIG. 13B is a cross-sectional view of the periphery of a thermal expansion member. This is a simulation result of the amount of movement of the movable frame in the optical axis direction at a temperature change of 55° C. when the inclination angle θ is changed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same members and elements are given the same reference numerals, and duplicated explanations will be omitted as appropriate. In each embodiment, an example of an imaging device to which an imaging element holding structure is applied will be shown.
First Embodiment
FIG. 1 is a perspective view of an imaging device 10, which is an example of an electronic device. With respect to the direction of the imaging device 10, the subject side is defined as the front side and the user side as the rear side, based on the direction in which a photographer (user) observes a subject through the imaging device 10. Thus, the up-down direction, the front-back direction, and the left-right direction are defined as shown in FIG. 1, as seen from a user facing the rear of the imaging device 10. Thus, FIG. 1(a) is a perspective view of the imaging device 10 as seen from the front side, and FIG. 1(b) is a perspective view of the imaging device 10 as seen from the rear side. In this embodiment, as an example of the imaging device 10, a lens-interchangeable camera capable of mounting a lens device to the camera body is shown, but this embodiment is also applicable to electronic devices having an imaging element.

The imaging device 10 has an exterior 10b composed of multiple members. The imaging device 10 has a mount 10a on the front side, to which an interchangeable lens (lens device) (not shown) can be attached. The axis passing through the center of the mount 10a approximately coincides with the optical axis P (see dashed line) of the imaging optical system of the interchangeable lens, i.e., the imaging optical axis.

Figure 2 is an exploded perspective view of the main parts of the imaging device 10 as seen from the rear side (user side). Note that the exterior part 10b is not shown in Figure 2. Also, in Figure 2 and subsequent figures, parts necessary for understanding this embodiment are shown, and unnecessary parts are omitted.

The imaging device 10 has a control board 100, an imaging element unit 200, a shutter unit 300, and a base member 400. The base member 400 holds a mount 10a that holds a lens device, the imaging element unit 200, and the shutter unit 300.

The imaging element unit 200 is configured to be adjustable in the distance (hereinafter, flange back) from the imaging surface of the imaging element 230 (see FIG. 4) to the mount 10a, and inclination of the imaging surface with respect to the base member 400. For example, the imaging element unit 200 is supported on the base member 400 by three screws 600a, 600b, and 600c and three adjustment washers (adjustment members) 500a, 500b, and 500c. The worker adjusts the thickness of the adjustment washers 500a, 500b, and 500c. This allows the flange back and the inclination of the imaging surface to be adjusted. Also, a coil spring member may be used as the adjustment member instead of the adjustment washers 500a, 500b, and 500c. When the above adjustment process is completed, the screws 600a, 600b, and 600c are adhesively fixed to the fixing unit 200b (see FIG. 3) of the imaging element unit 200 to prevent them from loosening.

The control board 100 and the base member 400 are fixed to the exterior part 10b. The control board 100 is mounted with a control IC 101 used to control the imaging signal, and a connector 102. The control board 100 is also mounted with various electronic components (not shown) such as chip resistors, ceramic capacitors, inductors, and transistors.

Next, the image sensor unit 200 will be described with reference to Figs. 3 and 4. In this embodiment, the imaging device 10 is equipped with an optical image blur correction mechanism that allows the image sensor unit 200 to be displaced in any direction within a plane perpendicular to the optical axis P. Figs. 3 and 4 are exploded perspective views of the image sensor unit 200.

The image sensor unit 200 has a movable unit 200a and a fixed unit 200b. The movable unit 200a can be displaced relative to the fixed unit 200b in any direction within a plane perpendicular to the optical axis P.

The fixed unit 200b has as its main components a front yoke 210, a base plate (fixed member) 250, a rear yoke 212a, a rear yoke 212b, and a magnetic member 254. The movable unit 200a has as its main components a movable frame (holding member) 220, a magnetic attraction plate 224, an image sensor board 232, a flexible board 240, and a flexible board 290.

First, the configuration of the movable unit 200a will be described. The movable unit 200a is a movable member including an image sensor 230. The image sensor 230 is a CMOS (complementary metal oxide semiconductor) image sensor or a CCD (charge-coupled device) image sensor, and converts an optical image of a subject into an electrical signal. An image sensor board 232 on which the image sensor 230 is mounted is adhesively fixed to the movable frame 220. An optical low-pass filter 231 is disposed in front of the image sensor 230 in the movable frame 220. The optical low-pass filter 231 is an optical element for preventing the occurrence of color moiré and the like.

The flexible substrate 240 and the flexible substrate 290 connect the movable unit 200a and the control substrate 100. The flexible substrate 290 and the flexible substrate 240 are both flexible printed circuit boards that have flexibility.

Three openings 225a, 225b, and 225c are formed in the movable frame 220. Three coils 241a, 241b, and 241c are mounted on the flexible substrate 240. The flexible substrate 240 is assembled and glued to the movable frame 220 from the front side, and the coils 241a, 241b, and 241c are housed inside the openings 225a, 225b, and 225c, respectively.

Next, the configuration of the fixed unit 200b will be described. The front yoke 210 shown in FIG. 3 has pillars 211a, 211b, and 211c that stand facing the base plate 250. One end of each of the pillars 211a, 211b, and 211c is press-fitted into the base plate 250. The front yoke 210 and the base plate 250 are joined together with the movable frame 220 sandwiched between them.

The base plate 250 has three openings 255a, 255b, and 255c formed at different positions when viewed from the optical axis P direction. Magnets 256a, 256b, and 256c are respectively incorporated in the openings 255a, 255b, and 255c. When viewed from the optical axis P direction, the magnets 256a, 256b, and 256c are formed in approximately the same positions and with approximately the same shapes as the corresponding coils 241a, 241b, and 241c. The magnets 256a, 256b, and 256c are arranged at positions where the centers of the magnets 256a, 256b, and 256c and the centers of the corresponding coils 241a, 241b, and 241c approximately coincide. A Hall element is mounted inside the windings of each of the coils 241a, 241b, and 241c.

In this way, a magnetic path is formed by the magnets 256a, 256b, and 256c installed on the base plate 250, and the coils 241a, 241b, and 241c are arranged in a magnetic field environment. The control board 100 controls the current of these coils 241a, 241b, and 241c to generate Lorentz forces in each of the coils 241a, 241b, and 241c. The movable frame 220 can be displaced in any direction in a plane perpendicular to the optical axis P using the Lorentz force as a thrust. Hall elements are mounted on the inside of the coils 241a, 241b, and 241c, respectively, and detect changes in magnetic force caused by the movable frame 220 moving relative to the base plate 250. Based on the detection signal of each Hall element, the relative displacement amount of the movable unit 200a with respect to the fixed unit 200b, that is, the displacement amount in any direction in a plane perpendicular to the optical axis P, can be detected.

Next, the holding structure of each part will be described. Fixed unit 200b is a support member fixed to base member 400 (Figure 2). Furthermore, movable unit 200a is magnetically biased in the direction of optical axis P toward fixed unit 200b by a magnetic attraction plate 224 arranged on movable unit 200a and a magnetic member 254 arranged on fixed unit 200b. Magnetic attraction plate 224 and magnetic member 254 are biasing members that bias movable unit 200a toward fixed unit 200b.

The movable frame 220 is equipped with thermal expansion members 261, 262, 263 and contact members 271, 272, 273. The movable frame 220 and the base plate 250 sandwich the rolling members, spheres 215a, 215b, 215c, via the thermal expansion members 261, 262, 263 and the contact members 271, 272, 273. This allows the spheres 215a, 215b, 215c to be supported so that they can roll. The position of the movable frame 220 in the direction of the optical axis P is determined by the thermal expansion members 261-263.

Next, the functions realized by this embodiment will be described. The movable unit 200a is supported by the fixed unit 200b in a state in which it can be displaced in any direction in a plane perpendicular to the optical axis P relative to the fixed unit 200b. When the movable unit 200a moves in a direction perpendicular to the optical axis P, an image blur correction operation that corrects optical image blur is realized.

The image blur directions in the imaging device 10 are the pitch direction, the yaw direction, and the roll direction. The pitch direction and the yaw direction are two directions around axes that are perpendicular to the optical axis P of the imaging optical system and perpendicular to each other, and the roll direction is a direction around an axis parallel to the optical axis P. When correcting image blur in the pitch direction, which is a rotation direction about an axis in the left-right direction, the movable unit 200a translates in the up-down direction. When correcting image blur in the yaw direction, which is a rotation direction about an axis in the up-down direction, the movable unit 200a translates in the left-right direction. When correcting image blur in the roll direction, which is a rotation direction about an axis in the front-rear direction, the movable unit 200a rotates around an axis parallel to the axis in the front-rear direction.

In addition, if the image sensor 230 heats up due to long-term video shooting, the base member 400, image sensor board 232, and movable frame 220 will expand in the direction of the optical axis P due to thermal expansion, and there is a concern that the flange back (the distance from the imaging surface of the image sensor 230 to the mount 10a) will increase.

In contrast, in this embodiment, when the temperature around the thermal expansion members 261, 262, and 263 changes, as shown in FIG. 7, the thermal expansion members 261, 262, and 263 deform so that their height in the direction of the optical axis P changes. This deformation of the thermal expansion members 261, 262, and 263 is used to cancel out the change in flange back caused by heat generation of the image sensor 230.

In addition, in the conventional technology disclosed in Patent Document 1, the only member capable of adjusting the flange back is the bimetal member, so that it is necessary to adjust the height of the bimetal member in the optical axis P direction during initial flange back adjustment. On the other hand, in this embodiment, the flange back adjustment member (adjustment washers 500a, 500b, 500c) is provided, so that height adjustment by the shape of the thermal expansion members 261, 262, 263 is not required. Therefore, it is possible to obtain a constant amount of flange back correction for each imaging device. Furthermore, according to this embodiment, the thermal expansion members 261, 262, 263 can be installed near the imaging element 230, which is a heat source, so that the flange back correction effect can be obtained efficiently.

Next, the configuration around the thermal expansion members 261, 262, and 263 will be described in detail with reference to FIG. 5. FIG. 5(a) is a front view (viewed from the mount 10a side) of the imaging element unit 200 with the front yoke 210 not shown. FIG. 5(b) is a cross-sectional view of the thermal expansion member 261 and its surroundings taken along the line A-A in FIG. 5(a).

In the following, only the area around the thermal expansion member 261 will be mentioned, but the areas around the other thermal expansion members 262 and 263 are also configured in a similar manner.

The thermal expansion member 261 is a molded part made of POM (polyacetal) and has a linear expansion coefficient of 0.0001 (mm/°C). The movable frame 220 is a molded part made of Mg (magnesium) alloy and has a linear expansion coefficient of 0.000027 (mm/°C). Thus, the linear expansion coefficient of the thermal expansion member 261 is greater than that of the movable frame 220. In addition, POM has a low coefficient of friction. For this reason, POM is a suitable material for a configuration that requires relative positional movement between the movable frame 220 and the thermal expansion member 261, as in this embodiment.

The thermal expansion member 261 has a first surface 261a which is an inclined surface that abuts against the movable frame 220. The first surface 261a abuts against the inclined surface 221a of the hole 221 formed in the movable frame 220. The first surface 261a is formed so as to form an acute angle with respect to the projection direction of light from the imaging lens to the imaging element 230. In other words, the first surface 261a is a tapered surface formed on the movable frame 220 side, tapering from the base plate 250 toward the movable frame 220.

The thermal expansion member 261 has a second surface 261b on the base plate 250 side that is parallel to a plane perpendicular to the optical axis P, and the second surface 261b abuts against the contact member 271. The contact member 271 is formed of a metal part with high surface hardness such as SUS, and ensures flatness for the ball 215a to roll on. The contact member 271 can be omitted if flatness can be ensured by the thermal expansion member 261 alone. The contact member 271 abuts against the ball 215a and has a horizontal surface 271a on which it can roll.

Next, the configuration of the regulating unit that regulates the range in which the sphere 215a can roll will be described. A configuration in which the regulating unit is provided on the movable frame 220 is known as a conventional image stabilization mechanism. However, in this embodiment, if the regulating unit is provided on the movable frame 220, the fitting length between the outer circumferential surface 261c of the thermal expansion member 261 and the inner wall surface 221b of the movable frame 220 cannot be sufficiently ensured. Therefore, when the thermal expansion member 261 moves in a plane perpendicular to the optical axis P of the movable frame 220, the thermal expansion member 261 is likely to tilt with respect to the plane perpendicular to the optical axis P, and there is a concern that controllability during image stabilization will be impaired. Alternatively, if the height of the thermal expansion member 261 in the optical axis P direction is increased to ensure the fitting length with the inner wall surface 221b of the movable frame 220, the height of the movable unit 200a in the optical axis P direction may increase, and the size of the imaging device 10 may become large.

In this embodiment, the thermal expansion member 261 has an inner wall surface (third surface) 261d parallel to the optical axis P that regulates the range in which the sphere 215a can roll. The thermal expansion member 261 has an outer peripheral surface (fourth surface) 261c that surrounds the inner wall surface 261d, and a convex protrusion 261e that fits into the inner wall surface 221b of the hole 221 of the movable frame 220 is formed on the outer peripheral surface 261c. The protrusion 261e is located at the end of the inner wall surface 221b of the hole 221 of the movable frame 220, and is a convex portion having an R shape. As a result, the thermal expansion member 261 fits into the movable frame 220 in the hole 221 of the movable frame 220 by line contact, and the fitting length can be secured. As a result, the contact member 271 provided in the thermal expansion member 261 can be prevented from tilting.

The space 221c (space in which the thermal expansion member 261 is disposed) surrounded by the inner wall surface 221b of the movable frame 220 and the outer peripheral surface 261c of the thermal expansion member 261 may be filled with thermal transfer grease. This can improve the thermal transfer of heat generated by the imaging element 230 to the thermal expansion member 261. This increases the amount of deformation of the thermal expansion member 261 in response to heat generated by the imaging element 230, which is expected to improve the correction effect of flange back change.

Next, a schematic diagram of flange back correction using the above configuration is shown in FIG. 7. FIG. 7(a)-FIG. 7(c) show cross-sectional views of the periphery of the thermal expansion member 261 when the temperature around the thermal expansion member 261 is normal, high, and low. In FIG. 7(b) and FIG. 7(c), the shape of the thermal expansion member 261 at normal temperature is shown by a two-dot chain line. As shown in FIG. 7, at high temperature, the thermal expansion member 261 expands according to the temperature rise difference and the linear expansion coefficient of the material. The thermal expansion member 261 deforms in a direction in which the height in the optical axis P direction increases, and the movable frame 220 moves in a direction in which the flange back shrinks. On the other hand, at low temperature, the thermal expansion member 261 deforms in a direction in which the height in the optical axis P direction decreases, and the movable frame 220 moves in a direction in which the flange back expands. That is, when the image sensor 230 generates heat, the heat of the image sensor 230 is transmitted to the thermal expansion member 261 via the image sensor board 232 and the movable frame 220, and the shape of the thermal expansion member 261 expands. As a result, the position of the movable frame 220 on the optical axis P moves in the direction in which the flange back shrinks. At this time, the base member 400 expands in the direction of the optical axis P due to thermal expansion, and the image sensor unit 200 moves in the direction in which the flange back extends. This makes it possible to make corrections to cancel out the change in flange back caused by heat generation by the image sensor 230.

Next, a method for deriving the optimal shape of the thermal expansion members 261, 262, and 263 will be described with reference to FIG. 6. In this embodiment, the movable frame 220 is supported and held at three points on the base plate 250 via the thermal expansion members 261, 262, and 263, the contact members 271, 272, and 273, and the spheres 215a, 215b, and 215c (see FIGS. 3 and 4). If the heights of the support parts in the optical axis P direction vary, the image sensor 230 held by the movable frame 220 will tilt with respect to the optical axis P. As a result, there is a concern that problems such as one-sided blurring (out of focus at the periphery of the screen) may occur. For this reason, it is desirable to have a configuration in which the above three support parts are less likely to be misaligned in the optical axis P direction. On the other hand, if the distances of the support parts from the image sensor 230 cannot be made uniform, or if the temperature distribution within the image sensor 230 is not uniform, differences will occur in the amount of heat transferred to the thermal expansion members 261, 262, and 263. If the thermal expansion members 261, 262, and 263 were all made to have the same shape, they would each undergo linear expansion according to the amount of heat transmitted to them, which could cause the image sensor 230 to tilt.

In this embodiment, this problem is solved by using the following formula to determine the shape of the thermal expansion member according to each support part. Note that in the following explanation, the thermal expansion member 261 will be used, but the same applies to the other thermal expansion members 262 and 263.

L = (T1 x Δt x C1) + (D1 x Δt x (C1-C2) x tan θ)
Here, L is the amount of movement of the movable frame 220 in a direction parallel to the optical axis P. T1 is the thickness of the bottom surface of the thermal expansion member 261. D1 is the radius of the circle at the center of the first surface 261a of the thermal expansion member 261. Δt is the temperature change of the thermal expansion member 261. θ is the inclination angle of the first surface 261a of the thermal expansion member 261. C1 is the linear expansion coefficient of the thermal expansion member 261 (POM = 0.0001 (mm/°C)). C2 is the linear expansion coefficient of the movable frame 220 (Mg = 0.000027 (mm/°C)).

The shape of the thermal expansion member will be explained with reference to FIG. 6. FIG. 6(a) is a perspective view of the thermal expansion member, and FIG. 6(b) is a front view of the thermal expansion member. FIG. 6(c) is a cross-sectional view of the thermal expansion member taken along the line B-B of FIG. 6(b).

The inclination angle of the first surface 261a, which is an inclined surface, is θ, half the width of the central part of the first surface 261a is D1, and the thickness of the bottom surface of the thermal expansion member 261 is T1. Two deformation modes mainly contribute to the movement amount of the movable frame 220 in the optical axis P direction due to the deformation of the thermal expansion member 261 (flange back correction amount). One is the part shown in the first term on the right side of the above equation (T1 x Δt x C1), which is calculated from the thickness of the bottom surface of the thermal expansion member 261, the linear expansion coefficient of the material, and the temperature change. The other is the part shown in the second term on the right side of the above equation (D1 x Δt x (C1-C2) x tan θ). This is the part calculated by converting the linear expansion difference between the movable frame 220 and the thermal expansion member 261 and the deformation amount due to temperature change into the optical axis P according to the angle of the inclined surface for the deformation of the thermal expansion member 261 in the direction perpendicular to the optical axis P (hereinafter referred to as deformation in the width direction).

For example, when the inclination angle θ is 0°, that is, when the first surface 261a is parallel to the plane 261b, only the first term contributes. In this case, as an example, if one wishes to obtain a temperature correction effect of about 20μ when the temperature difference is Δt = 55°C, the thickness T1 of the bottom surface of the thermal expansion member 261 needs to be 4 mm, which increases the height of the movable unit 200a in the optical axis direction and may increase the size of the imaging device 10.

On the other hand, by inclining the contact surface of the thermal expansion member 261 with the movable frame 220 at an angle, the correction effect of the second term is added, and the increase in the thickness T1 of the bottom surface of the thermal expansion member 261 can be suppressed. Specifically, if the radius D1 of the circle at the center of the first surface 261a of the thermal expansion member 261 is 2.45 mm, the temperature difference is Δt = 55°C, and the inclination angle θ is 60°, the correction amount due to deformation in the width direction is approximately 17 μm. By making the thickness of the bottom surface approximately 1 mm, the correction effect due to the thickness is approximately 6 μm, and a total correction effect of approximately 23 μm can be obtained without increasing the thickness in the optical axis direction.

In addition, the radius D1 of the circle at the center of the first surface 261a of the thermal expansion member 261 is set to be larger than the thickness T1 of the bottom surface of the thermal expansion member 261 (D1>T1). This makes it possible to reduce the thickness of the image sensor unit 200 in the optical axis direction, and as a result, the overall thickness of the image capture device 10 can be reduced.

Furthermore, by using the above formula to adjust the inclination angle θ of each of the thermal expansion members 261, 262, and 263 depending on how heat is transferred to them, it is also possible to adjust the amount of displacement L of each of the thermal expansion members 261, 262, and 263 in a direction parallel to the optical axis P of the movable frame 220. Figure 10 shows the results of a simulation calculation of the value of the amount of movement L of the movable frame 220 in a direction parallel to the optical axis P at a temperature change of 55°C (23°C → 78°C) when the inclination angle θ is 60°, 45°, and 30°.

When the image sensor 230 heats up due to long-term video shooting, the base member 400, image sensor substrate 232, and movable frame 220 expand in the direction of the optical axis P due to thermal expansion, and the flange back expands. By appropriately setting the inclination angle θ according to the amount of expansion, the change in flange back can be canceled.

With the above-described configuration, it is possible to provide an imaging apparatus that can suppress changes in flange focal length caused by heat during shooting while eliminating variations in the amount of flange focal length correction.
Second Embodiment
A second embodiment will be described in which a convex portion 261f having a convex shape is added to a first surface 261a, which is an inclined surface of a thermal expansion member 261. Note that the same components as those in the first embodiment are designated by the same symbols, and descriptions of overlapping parts will be omitted.

Figure 8(a) is a front view (viewed from the mount 10a side) of the image sensor unit 200 with the front yoke 210 not shown. Figure 8(b) is a cross-sectional view of the thermal expansion member 261 and its surroundings at the A-A cross section in Figure 8(a).

The thermal expansion member 261 has a first surface 261a, which is an inclined surface, on the movable frame 220 side. The first surface 261a is formed so as to form an acute angle with respect to the projection direction of light from the imaging lens to the imaging element 230. In other words, the first surface 261a is a tapered surface formed on the movable frame 220 side, tapering from the base plate 250 toward the movable frame 220.

Furthermore, a convex portion 261f having a convex shape is formed in the center of the first surface 261a, and the convex portion 261f abuts against the slope 221a of the hole 221 of the movable frame 220. The convex portion 261f is a convex portion having an R shape, and is in line contact with the slope 221a of the hole 221. This results in a configuration that is less susceptible to the effects of rough surface accuracy of the slope 221a of the hole 221 or deviations in the angle of the slope 261a of the thermal expansion member 261 due to processing tolerances.

Also, similarly to the first embodiment, the space 221c (space in which the thermal expansion member 261 is disposed) surrounded by the inner wall surface 221b of the movable frame 220 and the outer peripheral surface 261c of the thermal expansion member 261 may be filled with thermal transfer grease. In the configuration of this embodiment, the space 221c is enlarged, and therefore, by filling the space with grease, the effect of improving the thermal transfer of heat generated in the imaging element 230 to the thermal expansion member 261 is more pronounced. Therefore, the amount of deformation of the thermal expansion member 261 in response to heat generated by the imaging element 230 increases, and an improvement in the correction effect of the flange back change can be expected.
Third Embodiment
The third embodiment is an embodiment without an image stabilization mechanism. The same components as those in the first and second embodiments are designated by the same reference numerals, and descriptions of overlapping parts will be omitted.

Figure 9(a) is a front view (viewed from the mount 10a side) of the image sensor unit 200 with the front yoke 210 not shown. Figure 9(b) is a cross-sectional view of the thermal expansion member 261 and its surroundings at the A-A cross section in Figure 9(a).

The thermal expansion member 261 has a first surface 261a which is an inclined surface that abuts against the movable frame 220. The first surface 261a abuts against the inclined surface 221a of the hole 221 formed in the movable frame 220. The first surface 261a is formed so as to form an acute angle with respect to the projection direction of light from the imaging lens to the imaging element 230. In other words, the first surface 261a is a tapered surface formed on the movable frame 220 side, tapering from the base plate 250 toward the movable frame 220.

The thermal expansion member 261 also has a second surface 261g on the base plate 250 side that is parallel to a plane perpendicular to the optical axis P. The second surface 261g is an abutment surface that abuts against the base plate 250. In contrast to the first embodiment, this embodiment is configured such that the space in which the sphere 215a and the contact member 271 are disposed is filled with the molding material of the thermal expansion member 261. This makes it possible to provide a configuration that provides a flange back correction effect by the thermal expansion member 261 even in a configuration without an image blur correction mechanism.

In addition, the thickness T1 of the bottom surface of the thermal expansion member 261 can be made thicker than in a configuration having an image stabilization mechanism, and the amount of deformation of the thermal expansion member 261 in response to heat generated by the imaging element 230 increases, which is expected to improve the correction effect of flange back changes.

The disclosure of each of the above embodiments includes the following configurations:

(Configuration 1)
A base member capable of holding an imaging optical system;
A fixing member fixed to the base member;
a holding member that holds an imaging element and is supported by the fixed member;
a biasing member that biases the holding member toward the fixing member;
an adjustment member for adjusting a tilt of an imaging surface of the imaging element with respect to the base member;
a thermal expansion member that is disposed between the fixing member and the holding member and in a hole formed in the holding member and has a linear expansion coefficient larger than that of the holding member;
The thermal expansion member is
A tapered first surface formed on the holding member side;
an imaging optical system including an imaging member that is disposed on the fixed member side and that is parallel to a surface perpendicular to an optical axis of the imaging optical system;
(Configuration 2)
2. The electronic device according to configuration 1, wherein the holding member is supported by the fixing member so as to be displaceable within a plane perpendicular to the optical axis.
(Configuration 3)
3. The electronic device according to configuration 1 or 2, further comprising a contact member that abuts against the second surface of the thermal expansion member.
(Configuration 4)
4. The electronic device according to configuration 3, further comprising a rolling member provided between the contact member and the fixed member and in contact with the contact member and the fixed member.
(Configuration 5)
5. The electronic device according to any one of configurations 1 to 4, wherein the first surface is a tapered inclined surface that tapers from the fixing member toward the holding member.
(Configuration 6)
The thermal expansion member is
a third surface parallel to the optical axis that limits a range in which the rolling member can roll;
a fourth surface that is an outer circumferential surface of the thermal expansion member and surrounds the third surface;
5. The electronic device according to configuration 4, further comprising a protrusion on the fourth surface that fits into an inner wall surface of the hole.
(Configuration 7)
7. The electronic device according to any one of configurations 1 to 6, wherein the first surface of the thermal expansion member abuts against an inclined surface of the hole.
(Configuration 8)
7. The electronic device according to any one of configurations 1 to 6, wherein the thermal expansion member includes a protrusion formed on the first surface.
(Configuration 9)
9. The electronic device according to configuration 8, wherein the protrusion is in line contact with the inclined surface of the hole.
(Configuration 10)
When the amount of movement of the holding member in a direction parallel to the optical axis is L, the thickness of the bottom surface of the thermal expansion member is T1, the radius of the circle at the center of the first surface of the thermal expansion member is D1, the temperature change of the thermal expansion member is Δt, the inclination angle of the first surface is θ, the linear expansion coefficient of the thermal expansion member is C1, and the linear expansion coefficient of the holding member is C2, the thermal expansion member is:
L = (T1 x Δt x C1) + (D1 x Δt x (C1-C2) x tan θ)
10. The electronic device according to any one of configurations 1 to 9, having a shape that satisfies the following formula:
(Configuration 11)
When the radius of the circle at the center of the first surface is D1 and the thickness of the bottom surface of the thermal expansion member is T1,
D1>T1
11. The electronic device according to any one of configurations 1 to 10, wherein the following conditional expression is satisfied:
(Configuration 12)
The electronic device described in configuration 6, characterized in that a space surrounded by the inner wall surface of the hole and the fourth surface of the thermal expansion member is filled with thermal conductive grease.
(Configuration 13)
13. The electronic device according to any one of configurations 1 to 12, wherein the thermal expansion member is molded from POM.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. Parts of the above-described embodiments may be combined as appropriate.

10 Electronic device (imaging device)
400 Base member 250 Fixed member (base plate)
220 Holding member (movable frame)
224, 254 Pressing member 500 Adjustment member 261-263 Thermal expansion member

Claims (13)

A base member capable of holding an imaging optical system;
A fixing member fixed to the base member;
a holding member that holds an imaging element and is supported by the fixed member;
a biasing member that biases the holding member toward the fixing member;
an adjustment member for adjusting a tilt of an imaging surface of the imaging element with respect to the base member;
a thermal expansion member that is disposed between the fixing member and the holding member and in a hole formed in the holding member and has a linear expansion coefficient larger than that of the holding member;
The thermal expansion member is
A tapered first surface formed on the holding member side;
an optical axis of the imaging optical system and a second surface formed on the fixed member and parallel to the surface perpendicular to the optical axis of the imaging optical system; The electronic device according to claim 1, characterized in that the holding member is supported so as to be displaceable relative to the fixed member in a plane perpendicular to the optical axis. The electronic device according to claim 1, further comprising a contact member that contacts the second surface of the thermal expansion member. The electronic device according to claim 3, further comprising a rolling member provided between the contact member and the fixed member and abutting against the contact member and the fixed member. The electronic device according to claim 1, characterized in that the first surface is a tapered slope that tapers from the fixing member toward the holding member. The thermal expansion member is
a third surface parallel to the optical axis for restricting a range in which the rolling member can roll;
a fourth surface that is an outer circumferential surface of the thermal expansion member and surrounds the third surface;
The electronic device according to claim 4 , further comprising a protrusion on the fourth surface that fits into an inner wall surface of the hole. The electronic device according to claim 1, characterized in that the first surface of the thermal expansion member abuts against the inclined surface of the hole. The electronic device according to claim 1, characterized in that the thermal expansion member includes a protrusion formed on the first surface. The electronic device according to claim 8, characterized in that the protrusion makes line contact with the inclined surface of the hole. When the amount of movement of the holding member in a direction parallel to the optical axis is L, the thickness of the bottom surface of the thermal expansion member is T1, the radius of the circle at the center of the first surface of the thermal expansion member is D1, the temperature change of the thermal expansion member is Δt, the inclination angle of the first surface is θ, the linear expansion coefficient of the thermal expansion member is C1, and the linear expansion coefficient of the holding member is C2, the thermal expansion member is:
L = (T1 x Δt x C1) + (D1 x Δt x (C1-C2) x tan θ)
2. The electronic device according to claim 1, wherein the electronic device has a shape that satisfies the following formula: When the radius of the circle at the center of the first surface is D1 and the thickness of the bottom surface of the thermal expansion member is T1,
D1>T1
2. The electronic device according to claim 1, wherein the following condition is satisfied: The electronic device according to claim 6, characterized in that the space surrounded by the inner wall surface of the hole and the fourth surface of the thermal expansion member is filled with thermal transfer grease. The electronic device according to claim 1, characterized in that the thermal expansion member is molded from POM.