WO2022201727A1

WO2022201727A1 - Fresnel lens, electronic apparatus, and method for manufacturing fresnel lens

Info

Publication number: WO2022201727A1
Application number: PCT/JP2021/048825
Authority: WO
Inventors: 光太郎西村
Original assignee: ソニーセミコンダクタソリューションズ株式会社
Priority date: 2021-03-23
Filing date: 2021-12-28
Publication date: 2022-09-29
Also published as: JPWO2022201727A1

Abstract

The present invention improves the image quality of image data in an electronic apparatus that uses a Fresnel lens.　The Fresnel lens has a lens part and a plurality of ring bands. One of the two surfaces of the lens part is a flat surface, and the other of the two surfaces is a curved surface. The plurality of ring bands are formed in a concentric pattern around the optical axis. Furthermore, each of the plurality of ring bands has a substantially triangular cross section, the base of which is a line segment connecting two points on the curved surface. Additionally, in the plurality of ring bands, the vertical distance from the flat surface to a pair of vertices of the base becomes greater further away from the optical axis.

Description

Fresnel lens, electronic device, and method for manufacturing Fresnel lens

This technology relates to Fresnel lenses. Specifically, the present invention relates to a Fresnel lens manufactured by an imprint method, an electronic device, and a method for manufacturing a Fresnel lens.

Conventionally, Fresnel lenses have been used for the purpose of reducing lens thickness in various electronic devices. For example, an electronic device has been proposed in which a Fresnel lens and a light guide section for guiding light from the Fresnel lens to a solid-state imaging device are arranged, and the light guide section is adjusted so that each pixel has an angle of view that does not overlap. (See Patent Document 1, for example).

JP 2019-220941 A

In the conventional technology described above, the efficiency of using incident light is improved by adjusting the pixels so that they have angles of view that do not overlap. However, in the electronic device described above, when the Fresnel lens is manufactured by the imprint method, there is a possibility that air bubbles may be mixed in, causing an image defect and degrading the image quality of the image data.

This technology was created in view of this situation, and aims to improve the image quality of image data in electronic devices that use Fresnel lenses.

The present technology has been made to solve the above-described problems, and a first aspect of the present technology includes a lens portion having one of both surfaces that is flat and the other of the two surfaces having a curved surface; , each having a substantially triangular cross-section whose base is a line segment connecting two points on the curved surface, and the perpendicular distance from the plane to the opposite vertex of the base increases as the distance from the optical axis increases. A Fresnel lens with a plurality of large ring zones. This brings about the effect of suppressing the entrainment of air bubbles.

Further, in the first aspect, the larger the half angle of view of the Fresnel lens, the higher the height from the base to the opposite vertex. This brings about the effect of suppressing the entrainment of air bubbles.

Further, in the first side surface, the height is h, the half angle of view is α, and the taper angle between one of the two sides of the substantially triangular shape other than the base side and the optical axis is β. Assuming that the allowable value of is T, the following relational expression may be established between α, β and T. This brings about the effect of suppressing the amount of image loss.
{h×sin(α+β)}/(cosβcosα)<T

Also, in this first aspect, the vertical distances of the plurality of ring zones may be different from each other. This brings about the effect of suppressing the amount of image loss.

Further, in the first aspect, the plurality of ring zones includes a plurality of inner ring zones having a radius not exceeding a predetermined value and a plurality of outer ring zones having a radius larger than the predetermined value, and the plurality of inner ring zones The zones may have the same vertical distance, and the plurality of outer zones may have different vertical distances. This brings about the effect of suppressing the amount of image loss.

Further, in the first aspect, the plurality of ring zones have a larger radius than both the pair of first ring zones adjacent to each other and the pair of second rings adjacent to each other. The pair of first zones has the same vertical distance, the pair of second zones has the same vertical distance, and the pair of first zones and the pair of The second ring zone may have a different vertical distance from each other. This brings about the effect of suppressing the amount of image loss.

Further, in the first aspect, the plurality of annular zones may be formed by fresneling a spherical lens. This brings about the effect of making the lens thinner.

Further, in the first aspect, the plurality of annular zones may be formed by Fresneling an aspherical lens. This brings about the effect of suppressing the aberration.

Also, in this first aspect, the Fresnel lens may have negative optical power. This brings about the effect of diffusing the light.

Also, in this first aspect, the Fresnel lens may have positive optical power. This brings about the effect of condensing the light.

Further, in this first aspect, the Fresnel lens may have a rectangular shape when viewed from the direction of the optical axis. This has the effect of reducing the size of the Fresnel lens.

Further, in this first aspect, the shape of the Fresnel lens when viewed from the direction of the optical axis may be a rounded quadrangle. This brings about the effect of improving the peeling resistance.

In addition, a second aspect of the present technology is a lens portion having a flat surface on one side and a curved surface on the other side, and a lens section formed concentrically around an optical axis and connecting two points on the curved surface. a Fresnel lens comprising a plurality of annular zones each having a substantially triangular cross-section with a line segment as the base, and a vertical distance from the plane to the opposite vertex of the base increases with increasing distance from the optical axis; and the Fresnel lens. and a solid-state imaging device that generates image data by photoelectric conversion of light from a lens. This brings about the effect of improving the image quality of the image data.

Further, in the second aspect, a predetermined number of pixels may be arranged in a portion of the image plane of the solid-state imaging device that faces the base. This brings about the effect of improving the image quality of the image data.

A third aspect of the present technology includes a lens material supplying procedure for supplying a liquid lens material to a predetermined surface, a lens portion having one of both surfaces flat and the other of the two surfaces curved, and an optical axis. Concentric circles are formed around the curved surface, each of which has a substantially triangular cross-section whose base is a line segment connecting two points on the curved surface, and the perpendicular distance from the plane to the opposite vertex of the base is away from the optical axis. The method for manufacturing a Fresnel lens includes a pressing step of pressing a mold having a plurality of ring zones as small as the lens material against the lens material, and a curing step of curing the lens material. This brings about the effect of suppressing the entrainment of air bubbles.

Further, in the third aspect, the predetermined surface may be a surface on a predetermined substrate before dicing. This brings about the effect of suppressing the entrainment of air bubbles.

Further, in the third aspect, the predetermined surface may be a surface on a predetermined chip after dicing. This brings about the effect of suppressing the entrainment of air bubbles.

Further, in the third aspect, the lens material may be a photocurable resin, the mold may be transparent, and light having a predetermined wavelength may be irradiated in the curing procedure. This brings about an effect that heat treatment becomes unnecessary.

It is a mimetic diagram showing an example of composition of a fingerprint authentication device in a 1st embodiment of this art. It is a figure which shows one structural example of the laminated structure of the solid-state image sensor in 1st Embodiment of this technique. 1A and 1B are a cross-sectional view and a top view showing a configuration example of a Fresnel lens according to a first embodiment of the present technology; It is a sectional view showing an example of composition of a ring zone part and a lens part in a 1st embodiment of this art. It is a figure for demonstrating the calculation method of the image defect amount in 1st Embodiment of this technique. It is a figure showing an example of a simulation result in a 1st embodiment of this art. It is a figure showing an example of a parameter setting in a 1st embodiment of this art. It is a figure showing an example of a manufacturing method of a Fresnel lens in a 1st embodiment of this art. It is a figure which shows an example of each manufacturing method of 1st Embodiment of this technique, and a comparative example. It is a flow chart which shows an example of a manufacturing method of a Fresnel lens in a 1st embodiment of this art. It is a figure showing an example of image data in a 1st embodiment of this art. It is a top view which shows an example of the Fresnel lens in a comparative example. It is a sectional view showing an example of composition of a Fresnel lens in a 2nd embodiment of this art. It is a mimetic diagram showing one example of composition of an observation device for research in a 2nd embodiment of this art. It is a sectional view showing an example of composition of a Fresnel lens in a 3rd embodiment of this art. It is a top view showing one example of composition of a Fresnel lens in a 4th embodiment of this art. It is a figure which shows an example of the manufacturing method of the Fresnel lens until discharge of a lens material in 5th Embodiment of this technique. It is a figure which shows an example of the manufacturing method of the Fresnel lens to mold release of a transparent mold in 5th Embodiment of this technique. It is a flow chart which shows an example of a manufacturing method of a Fresnel lens in a 5th embodiment of this art. It is a figure which shows an example of the manufacturing method of the Fresnel lens until the application|coating of the lens material in 5th Embodiment of this technique. 1 is a block diagram showing a schematic configuration example of a vehicle control system; FIG. FIG. 4 is an explanatory diagram showing an example of an installation position of an imaging unit;

Hereinafter, a form for carrying out the present technology (hereinafter referred to as an embodiment) will be described. Explanation will be given in the following order.
1. First Embodiment (Example in which the vertical distance of the Fresnel lens is increased toward the outside)
2. Second embodiment (an example in which the vertical distance of a Fresnel lens having positive optical power is increased toward the outside)
3. Third Embodiment (Example in which the vertical distance of a Fresnel lens including an aspherical lens portion is increased toward the outside)
4. Fourth embodiment (an example in which the vertical distance of a rounded square Fresnel lens is increased toward the outside)
5. Fifth Embodiment (Example of manufacturing a Fresnel lens whose vertical distance is larger toward the outer side for each chip)
6. Example of application to mobile objects

<1. First Embodiment>
[Configuration example of fingerprint authentication device]
FIG. 1 is a schematic diagram showing a configuration example of a fingerprint authentication device 700 according to an embodiment of the present technology. The fingerprint authentication device 700 is a device that performs fingerprint authentication, and includes the solid-state imaging device 100 as a fingerprint sensor section for detecting fingerprints. Furthermore, the fingerprint authentication device 700 includes a processing section 702 and a display section 704 . The processing unit 702 is a device that authenticates fingerprints detected by the solid-state imaging device 100, and is implemented by, for example, a personal computer. A display unit 704 is a device for displaying fingerprints and authentication results detected by the solid-state imaging device 100. For example, a CRT (Cathode Ray Tube) display device, a liquid crystal display (LCD) device, an OLED (Organic Light Emitting Diode) ) device or the like.

Specifically, the solid-state imaging device 100 captures an image of the fingerprint of the finger 900 under the control of the processing unit 702, and transmits the image data to the processing unit 702 via the signal line. Then, the processing unit 702 compares the received image data with registered information, which is a fingerprint image, registered in the processing unit 702 in advance, and determines whether the authentication is successful or not. Then, the processing unit 702 outputs the authentication result and the captured fingerprint image to the display unit 704 .

The solid-state imaging device 100 also includes a cover glass 400 , a Fresnel lens 200 and a solid-state imaging device 300 . The Fresnel lens 200 is arranged below the cover glass 400 with the surface of the cover glass 400 on which fingers 900 are placed as the upper surface, and the solid-state imaging device 300 is arranged below the Fresnel lens 200 .

The Fresnel lens 200 has negative optical power. In other words, Fresnel lens 200 functions as a concave lens. The details of the structure of this Fresnel lens 200 will be described later. An optical path of light passing through the Fresnel lens 200 is omitted in the figure.

The solid-state imaging device 300 is, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor, which photoelectrically converts light from the Fresnel lens 200 to generate an analog electric signal. is. The generated electrical signal is converted into digital pixel data in the image data using a processing circuit or the like.

It should be noted that the fingerprint authentication device 700 may be a device that authenticates not only the fingerprint but also the vein of the user.

Also, although image data from the solid-state imaging device 100 is used for fingerprint authentication, the configuration is not limited to this. A solid-state imaging device 100 can be provided in the face authentication device, and image data can be used for face authentication. The solid-state imaging device 100 can also be provided in a device (for example, an iris authentication device) other than a device for fingerprint authentication, face authentication, or vein authentication.

[Configuration example of solid-state imaging device]
FIG. 2 is a diagram showing one configuration example of the laminated structure of the solid-state imaging device 300 according to the first embodiment of the present technology. This solid-state imaging device 300 includes a circuit chip 302 and a pixel chip 301 stacked on the circuit chip 302 . These chips are electrically connected, for example, by Cu--Cu bonding. In addition to Cu--Cu bonding, vias and bumps can also be used for connection.

A plurality of pixels 310 are arranged in a two-dimensional grid on the pixel chip 301 . In this pixel chip 301, an effective area in which effective pixels 310 (for example, unshaded pixels) are arranged is rectangular. Invalid pixels 310 (for example, shaded pixels) are arranged in areas other than the valid area. A region surrounded by a dashed line in the figure indicates an effective region. Hereinafter, the axis parallel to the rows in which the pixels 310 are arranged is defined as the X axis, and the axis parallel to the columns in which the pixels 310 are arranged is defined as the Y axis. Let the axis perpendicular to the X-axis and the Y-axis be the Z-axis. The Z axis is an axis parallel to the optical axis. Each pixel 310 generates a pixel signal by photoelectric conversion. The XY plane on which the pixels 310 are arranged corresponds to the image plane of the solid-state imaging device 300 .

In the circuit chip 302, a drive circuit for driving each pixel 310 and a signal processing circuit for performing predetermined signal processing on pixel signals are arranged. Signal processing performed by the signal processing circuit includes AD (Analog to Digital) conversion processing, CDS (Correlated Double Sampling) processing, and the like. The signal processing circuit generates image data and transmits it to the processing unit 702 .

Although two chips are stacked in the solid-state imaging device 300, three or more chips can be stacked. Also, the circuits and elements in the solid-state imaging device 300 can be arranged on one semiconductor chip without stacking.

[Configuration example of Fresnel lens]
FIG. 3 is a cross-sectional view and a top view showing one configuration example of the Fresnel lens 200 according to the first embodiment of the present technology. In the figure, a is an example of a cross-sectional view of the Fresnel lens 200 when viewed from the Y-axis direction, and b is an example of a top view of the Fresnel lens 200 when viewed from the Z-axis direction.

As illustrated in a in the figure, one of both surfaces of the Fresnel lens 200 is flat, and the other has a serrated cross section. The Fresnel lens 200 is arranged such that the sawtooth-shaped surface faces the cover glass 400 and the flat surface contacts the image plane of the solid-state imaging device 300 . Assuming that the direction toward the cover glass 400 is the upward direction, the plane is the bottom surface.

　On the upper surface, each of the saw blades is circular when viewed from above, so they are hereinafter referred to as "zones". Further, in the Fresnel lens 200, the upper portion where the annular zone is formed is called "annular zone portion 210", and the lower portion thereof is called "lens portion 220". A plurality of ring zones such as

ring zones

211 and 212 are formed in the ring zone portion 210 . A dotted curve indicated by a in FIG. However, the annular zone portion 210 and the lens portion 220 are integrally formed, and are not formed by connecting them with an adhesive or the like.

The lower surface of the lens portion 220 is flat as described above. On the other hand, the upper surface of the lens portion 220 is curved. The thickness from the upper surface to the lower surface increases as the distance from the optical axis passing through the center of the lens increases. The dashed-dotted line a in the figure indicates the optical axis. Moreover, the curved surface of the lens part 220 is, for example, a spherical surface. In other words, the lens portion 220 is a concave lens with one spherical surface.

In addition, in the ring zone portion 210 , the cross-sectional shape of each ring zone is a substantially triangular shape with two points on the curved surface of the lens portion 220 as bases. Here, the term "substantially triangular" means a figure whose sides are not strictly straight but are close to straight and can be approximated to a triangle. Since the cross section is approximately triangular, each ring zone functions as a prism.

In the n-th ring zone (n is an integer) from the center, the vertical distance H _n (in other words, thickness) and This vertical distance _Hn is set to a larger value as the annular zone is further away from the optical axis. In other words, the thickness of the Fresnel lens 200 increases with increasing distance from the optical axis.

Also, as illustrated in b in the figure, a plurality of ring zones such as

ring zones

211 and 212 are formed concentrically around the optical axis when viewed from the Z-axis direction. A black dot in the figure indicates the lens center through which the optical axis passes. A general Fresnel lens has a circular shape when viewed from the optical axis direction, but the effective area of the lower solid-state imaging device 300 is rectangular (square or rectangle). For this reason, the Fresnel lens 200 is also trimmed into a rectangle along the boundary of its effective area. This shape allows the size of the Fresnel lens 200 to be smaller than if it were circular.

In summary, the lower surface of the lens part 220 is flat, and the upper surface is curved (such as a spherical surface). A plurality of ring zones such as

ring zones

211 and 212 are formed concentrically around the optical axis. Each of these annular zones has a substantially triangular cross section whose base is a line segment connecting two points on the curved surface of the lens portion 220 .

Also, the vertical distance _Hn from the lower surface (flat surface) of the lens portion 220 to the opposite vertex is set to a larger value as the distance from the optical axis increases. For example, if the vertical distance of the innermost zone is H1, the vertical distance of the _second innermost zone is _H2 , and the vertical distance of the outermost zone is _HN , then the distance between them is: formula is established.
H ₁ <H ₂ <...<H _N ... Formula 1

As exemplified in Equation 1, the vertical distances of each of the plurality of ring zones are different from each other.

Note that the relationship between the respective vertical distances of the ring zones is not limited to Equation 1. For example, as shown in the following formula, the vertical distance can be set to gradually increase from the middle.
H1=H2 ₌ ...= _H47 < _H48 < _H49 <...< _HN ... Formula ₂

In Equation 2, the vertical distance of each of the inner zones less than the radius corresponding to H ₄₇ is the same. Also, the respective vertical distances of the outer zones of radius greater than the radius corresponding to H ₄₇ are different from each other.

Alternatively, each value of the vertical distance can be set such that the following equation holds.
H ₁ =H ₂ <H ₃ =H ₄ < H _N−1 =H _N Equation 3

In Equation 3, the vertical distances of the first and second zones are the same. Also, the vertical distances of the third and fourth rings, which have larger radii than them, are the same. The first and second vertical distances are different from the third and fourth vertical distances. Thereafter, similarly, the vertical distances of a pair of adjacent ring zones are set to be the same.

As illustrated in the figure, by increasing the vertical distance _Hn as the distance from the optical axis increases, air bubbles are less likely to enter when the Fresnel lens 200 is manufactured by the manufacturing method described later.

FIG. 4 is a cross-sectional view showing one configuration example of the annular zone portion 210 and the lens portion 220 according to the first embodiment of the present technology. When a plurality of ring zones in the ring zone portion 210 are translated upward and the inner wall surfaces are connected, a spherical surface having a positive curvature K (in other words, a spherical surface of a concave lens) is formed. A thick dotted line in the figure indicates a spherical surface whose curvature K has a positive value.

Moreover, each of the annular zones has a substantially triangular cross section as described above. Let h be the height from the base of this approximate triangle to the opposite vertex. For example, the height h of each ring zone is set to the same value. In this case, if those zones are formed on a plane, the vertical distance _Hn from that plane will be the same value as the height h, and will be the same for all zones.

However, as described above, the lens portion 220 has a concave lens shape, and a plurality of annular zones are formed on its curved surface. Therefore, the vertical distance _Hn from the lower surface (flat surface) of the lens portion 220 increases as the distance from the optical axis increases. In this way, the Fresnel lens 200 can also be regarded as having a shape in which a general Fresnel lens is formed on a concave lens.

It should be noted that although the heights h of the plurality of ring zones are the same, they can be set to different values. Even in this case, the shape of the curved surface of the lens portion 220 is adjusted so as to satisfy any one of Equations 1 to 3.

FIG. 5 is a diagram for explaining the method of calculating the image loss amount in the first embodiment of the present technology. Attention is paid to a ring zone 211 among the plurality of ring zones. A cross section of the annular zone 211 viewed from the Y-axis direction is substantially triangular, and its vertices are A, B, and C. As shown in FIG. Vertices B and C are points on the curved surface of lens portion 220 . The dashed-dotted line in the figure indicates the curved surface of the lens portion 220 . In addition, although the dashed-dotted line draws an arc macroscopically, since it is microscopically close to a straight line, it is represented by a straight line in the figure. Also, the inner side AC is macroscopically a part of an arc with a curvature K, but is microscopically close to a straight line, so it is represented by a straight line in the figure. Strictly speaking, the side AC is not a straight line, so the cross section of the annular zone 211 is a substantially triangular shape that is close to a triangular shape.

Let the side BC be the base of the approximate triangle. In this case, vertex A is the opposite vertex to its base. Side AB corresponds to the outer wall surface farther from the optical axis, and side AC corresponds to the inner wall surface closer to the optical axis. When the inner wall surface is continuous to form a spherical surface of a concave lens, the side AB is shorter than the side AC. In addition, at least one or more predetermined number of pixels are arranged in a portion of the image plane of the solid-state imaging device 300 facing the side BC (bottom side) in the X-axis and Y-axis directions. The same applies to other ring zones. In other words, each ring spans a predetermined number of pixels.

Next, focus on the area around side AB. Let P2 be the intersection of a perpendicular drawn from vertex A to the image plane of the solid-state imaging device 300 and the image plane, and D be the intersection of the perpendicular and side BC. Also, let P0 be the intersection of a perpendicular line drawn from the vertex B to the image plane and the image plane.

Also, let the angle of view of the Fresnel lens 200 be 2α (α is a real number). In this case, the angle formed by the optical path of the incident light 501 to the vertex A and the optical axis is the half angle of view α. Also, the optical path of the incident light 502 to the vertex B is parallel to the incident light 501 .

Assuming that the refractive index of air is about 1 and the refractive index of Fresnel lens 200 is greater than 1 (such as 1.5), Fresnel's law dictates that a portion of each of

incident light

501 and 502 will be refracted less than α. Bend at an angle. Let P1 be the intersection of the optical path of the refracted light 504 corresponding to the incident light 502 and the image plane, and let P3 be the intersection of the optical path of the refracted light 503 corresponding to the incident light 501 and the image plane. Assuming that the horizontal distance from P0 to P1 is x1 and the horizontal distance from P2 to P3 is x2, x1 is smaller than x2.

Here, if the upper surface of the Fresnel lens 200 is not serrated but is a spherical surface of a concave lens, the incident point is determined from the intersection of the optical path of the refracted light starting from the incident point of the light on the spherical surface and the image plane. The horizontal distance x to the intersection of the perpendicular line passing through and the image plane increases toward the outside. However, since the top surface of the Fresnel lens 200 is serrated, the outer horizontal distance x1 is smaller than the horizontal distance x2, as described above. As a result, in the image data, a circular line is generated along the annular zone. The width of this line is hereinafter referred to as "image defect amount". Consider a method for calculating this image loss amount.

Extend the line segment AD upward, and let E be a predetermined point on the extension line. Let F be the point of intersection of a straight line passing through E and parallel to the X axis and the optical path of the incident light 501 , and let G be the point of intersection of the straight line and the optical path of the incident light 502 . The length L of the side FG corresponds to the amount of image loss. Also, let H be the intersection of a perpendicular line drawn from the point F to the optical path of the incident light 502 and the optical path.

∠EFA is 90°-α from the formula for the sum of interior angles of a triangle. Since the incident lights 501 and 502 are parallel, ∠FGH is also 90°-α. Therefore, the length M of the side FH can be expressed by the following equation.
M=L×sin(90°−α) Equation 4
In the above equation, sin() denotes a sine function. Also, the units of M and L are, for example, micrometers (μm), and the unit of α is, for example, degrees.

On the other hand, ∠BAD, which is the angle between the outer side AB and the optical axis, is defined as the taper angle β. Also, the length of the side AD corresponds to the height h described above. Therefore, if the cosine function is cos(), the side AB is h/cosβ. The distance from the vertex _A to P2 corresponds to the vertical distance Hn described above.

Also, ∠BAE is 180°-β from the exterior angle theorem of a triangle. Here, if the perpendicular drawn from the vertex A to the optical path of the incident light 502 and the intersection point with the optical path are I, ∠BAE is 180°-β, so ∠IAB is 90°-α-β. . Since ∠IAB is 90°-α-β, ∠IBA is α+β from the formula for the sum of interior angles of a triangle. Since the incident lights 501 and 502 are parallel, the length of side AI is also the same value as side FH (ie, M). Since ∠IBA is α+β and side AB is h/cosβ, M can be expressed by the following equation.
M=h×sin(α+β)/cosβ Equation 5
In the above formula, the unit of h is, for example, micrometers (μm), and the unit of β is, for example, degrees.

Eliminating M from Equations 4 and 5 and transforming them yields the following equations.
{h×sin(α+β)}/(cosβcosα)=L Equation 6

From Equation 6, the image loss amount L is defined by the ring zone height h, the half angle of view α, and the taper angle β. When the half angle of view α is a fixed value and the heights h of the ring zones are the same, the taper angle β usually increases toward the outer side, and as a result, the image loss amount L increases. Further, when the half angle of view α is fixed and the heights h of the annular zones are not uniform, the higher the height h, the larger the image defect amount L becomes.

As the image loss amount L increases, the image quality of the image data deteriorates, and the accuracy of performing fingerprint authentication or the like decreases. Let T be the permissible value of the image loss amount L for achieving a certain level of accuracy. In this case, the height h, the half angle of view α, and the taper angle β are set to values that satisfy the following equations for each ring zone.
{h×sin(α+β)}/(cosβcosα)<T Expression 7

In order to satisfy Expression 7, it is preferable to increase the height h as the half angle of view α increases.

FIG. 6 is a diagram showing an example of simulation results in the first embodiment of the present technology. As illustrated in the figure, part of the incident light is reflected by the surface of the Fresnel lens 200, and the reflected light is re-reflected by the upper surface of the cover glass 400 (in other words, the display surface). The re-reflected light is re-reflected on the surface of Fresnel lens 200 .

FIG. 7 is a diagram showing a parameter setting example in the first embodiment of the present technology. In Case 1, the half angle of view α was set to 80 degrees, the minimum taper angle β was set to 5 degrees, and the height h of all ring zones was made uniform to 10 micrometers (μm). In this case 1, from Equation 6, 57.6 micrometers (μm) was calculated as the largest image loss amount. As a result of simulation, 66 micrometers (μm) was calculated as the largest image defect amount for this case 1 . The theoretical value obtained by Equation 6 is close to the simulation result.

Also, in case 2, the half angle of view α and the minimum taper angle β were set to be the same as in case 1, and the height h of all ring zones was adjusted to 30 micrometers (μm). In this case 2, 172.8 micrometers (μm) was calculated as the largest image loss amount from Equation 6. As a result of the simulation, 177 micrometers (μm) was calculated as the largest image defect amount for this case 2 . The theoretical value obtained by Equation 6 is close to the simulation result.

Also, in case 3, the half angle of view α and the minimum taper angle β were the same as in case 1, and the height h of all ring zones was adjusted to 7 micrometers (μm). In Case 3, the largest image loss amount was calculated as 40.3 micrometers (μm) from Equation 5.

For example, assume a case where the solid-state imaging device 100 is used for fingerprint authentication. Generally, the pitch of the fingerprint ridges is 400 micrometers (μm). Assume that the allowable value T must be set to 40 micrometers (μm), which is 1/10 of the pitch, in order to achieve a certain level of accuracy. In this case, from the calculation results of Cases 1 to 3, it is desirable to set the height h to less than 7 micrometers (μm).

In cases 1 to 3, only the height h is adjusted, but instead of the height h, the half angle of view α and the taper angle β can also be adjusted in order to satisfy Equation 7. Also, two or more of the height h, the half angle of view α, and the taper angle β can be adjusted.

[Manufacturing method of Fresnel lens]
FIG. 8 is a diagram showing an example of a method for manufacturing the Fresnel lens 200 according to the first embodiment of the present technology. As illustrated in a in the figure, the Fresnel lens 200 manufacturing system applies a liquid lens material 620 to the upper surface of the sensor substrate 610 by spin coating or the like. Here, the sensor substrate 610 is a substrate before being diced into a plurality of chips, and circuits such as pixels are formed on the substrate before forming the Fresnel lens 200 . As the lens material 620, for example, a photocurable (ultraviolet curable, etc.) resin (acrylic resin, epoxy resin, etc.) is used. By using a photocurable resin, heat treatment is not required when the resin is cured.

Next, as illustrated in b in the figure, the manufacturing system presses (that is, embosses) a transparent mold 630 onto the lens material 620 for each region corresponding to the chip. Here, the transparent mold 630 has a ring zone portion 631 and a lens portion 632, and the ring zone portion 631 is on the lower side during embossing.

The lens portion 632 has a convex lens shape with one flat surface and the other curved surface (such as a spherical surface). A plurality of annular zones are formed concentrically around the optical axis in the annular zone portion 631 . Each of these annular zones has a substantially triangular cross section whose base is a line segment connecting two points on the curved surface of the lens portion 632 . Also, the vertical distance (in other words, thickness) from the lower surface (flat surface) of the lens portion 632 to the opposite vertex of the base decreases as the distance from the optical axis increases. Also, connecting the inner wall surfaces of each of the plurality of annular zones forms a spherical surface with a negative curvature K (in other words, the spherical surface of a convex lens). In addition, the transparent mold 630 is an example of the mold described in the claims.

Then, as exemplified by c in the figure, the manufacturing system irradiates light of a predetermined wavelength (such as ultraviolet light) from above through the transparent mold 630 to harden the lens material 620 .

Subsequently, as illustrated in d in the figure, the manufacturing system releases the transparent mold 630 and performs various processes such as dicing.

As shown in the figure, a manufacturing method in which a mold is pressed against a resin to form a desired shape is called an imprint method. The imprint method can efficiently manufacture the Fresnel lens 200 .

FIG. 9 is a diagram showing an example of a manufacturing method for each of the first embodiment and the comparative example of the present technology. a and b in the figure are examples of cross-sectional views before and after embossing of the transparent mold 630 in the first embodiment of the present technology. c and d in the figure are examples of cross-sectional views before and after stamping of the transparent mold 635 in the comparative example.

As exemplified by a in the figure, the vertical distance between the annular zones of the transparent mold 630 decreases as the distance from the optical axis increases. In other words, the thickness of the transparent mold 630 becomes thinner with increasing distance from the optical axis. Therefore, during embossing, the central portion of the transparent mold 630 first comes into contact with the lens material, and as the downward pressing progresses, the contacting portion spreads from the inside to the outside. Therefore, air can escape to the outside during embossing, and air bubbles can be prevented from entering the lens material (so-called bubble entrapment).

Then, as exemplified by b in the figure, a Fresnel lens 200 is formed in which the vertical distance (thickness) of each annular zone increases with increasing distance from the optical axis.

In addition, since the transparent mold 630 has a structure in which the central portion protrudes, the transparent mold 630 can be easily cleaned, and the occurrence of residue defects can be suppressed. Thereby, the yield can be improved.

Here, a Fresnel lens in which the vertical distance (thickness) of each ring zone is the same is assumed as a comparative example.

As illustrated in c in the figure, when manufacturing the Fresnel lens of the comparative example, a transparent mold 635 having the same vertical distance (thickness) of each annular zone is used. With this shape, there is no way for air to escape during embossing. For this reason, there is a risk that bubbles will form, as indicated by d in FIG.

In addition, since the transparent mold 635 of the comparative example is more difficult to clean than the transparent mold 630, residue defects may occur, making it difficult to improve the yield.

FIG. 10 is a flow chart showing an example of a method for manufacturing the Fresnel lens 200 according to the first embodiment of the present technology. The manufacturing system applies the liquid lens material 620 to the upper surface of the sensor substrate 610 by spin coating or the like (step S901).

Next, the manufacturing system stamps the transparent mold 630 for each area corresponding to the chip (step S902). Then, the manufacturing system irradiates ultraviolet rays or the like to harden the lens material 620 (step S903). Subsequently, the manufacturing system releases the transparent mold 630 (step S904), performs various processes such as dicing, and finishes manufacturing the Fresnel lens 200. FIG.

FIG. 11 is a diagram showing an example of image data according to the first embodiment of the present technology. In the figure, a is an example of image data when the height h is 10 micrometers (μm). b in the figure is an example of image data when the height h is 130 micrometers (μm).

As illustrated by a and b in the figure, the width of the circular line (that is, the amount of image loss) increases as the height h increases.

In addition, as described above, the Fresnel lens 200 suppresses image defects due to bubble inclusions and residue defects, so the image quality of image data can be improved more than in the comparative example.

FIG. 12 is a top view showing an example of a Fresnel lens in a comparative example. As exemplified in the figure, in the comparative example, there is a possibility that bubble entrapment and residue defects may occur. As a result, image defects occur and the image quality of the image data deteriorates.

As described above, in the first embodiment of the present technology, since a plurality of ring zones having a vertical distance that increases with increasing distance from the optical axis is formed in the Fresnel lens 200, air bubbles are mixed ( foam) can be suppressed. Thereby, the image quality of image data can be improved.

<2. Second Embodiment>
In the first embodiment described above, the Fresnel lens 200 functions as a lens (concave lens) having negative optical power. is difficult. The Fresnel lens 200 of this second embodiment differs from that of the first embodiment in that it has positive optical power.

FIG. 13 is a cross-sectional view showing one configuration example of the Fresnel lens 200 according to the second embodiment of the present technology. When the plurality of annular zones in the Fresnel lens 200 of the second embodiment are translated upward and the inner wall surfaces are connected, a spherical surface having a negative curvature K (in other words, a spherical surface of a convex lens) is formed. be. Therefore, the Fresnel lens 200 has positive optical power. The solid-state imaging device 100 using the Fresnel lens 200 configured as shown in the figure can be applied to, for example, an observation device for research.

Note that in the second embodiment, the image loss amount L is calculated with the angle between the inner side of the two sides of the substantially triangular shape other than the base side and the optical axis being the taper angle β.

A case where the solid-state imaging device 100 is applied to a research observation device for a sample 904 such as cells will be described with reference to FIG. Specifically, the solid-state imaging device 100 according to this embodiment can be applied to a device that observes a sample 904 such as cells mounted on a cover glass 402 from a close position. As shown in the figure, the solid-state imaging device 100 according to this embodiment can be arranged so as to be in contact with a cover glass 402 on which a sample 904 is mounted. The solid-state imaging device 100 arranged in this manner can function like a microscope without an objective lens, and can observe the sample 904 in detail with a simple configuration. In other words, for example, the solid-state imaging device 100 can function as a research or medical observation device such as a lensless microscope for distinguishing, sorting, and separating cells, viruses, and the like. Note that the cover glass 402 is not limited to a glass material, and may be a PET (Poly-Ethylene Terephthalate) resin or the like as long as it is a transparent member.

Thus, according to the second embodiment of the present technology, since the Fresnel lens 200 has positive optical power, it can be used for a research observation device or the like.

<3. Third Embodiment>
In the above-described first embodiment, the spherical lens is fresneled to form the ring zone portion 210, but it is difficult to suppress aberration with this shape. The Fresnel lens 200 of the third embodiment differs from that of the first embodiment in that the aspherical lens is Fresneled.

FIG. 15 is a cross-sectional view showing one configuration example of the Fresnel lens 200 according to the third embodiment of the present technology. The Fresnel lens 200 of the third embodiment differs from that of the first embodiment in that an aspherical lens is Fresnelized to form a ring zone portion 210 . When the plurality of ring zones of the ring zone portion 210 are moved upward in parallel to connect the wall surfaces, the aspheric surface of the concave lens is formed. Aberration can be suppressed by Fresneling the aspherical lens.

Note that the second embodiment can be applied to the third embodiment.

As described above, according to the third embodiment of the present technology, the aspherical lens is Fresnel, so aberration can be suppressed.

<4. Fourth Embodiment>
In the above-described first embodiment, the Fresnel lens 200 is trimmed into a rectangular shape, but in this shape, stress concentrates on the four corners and the Fresnel lens 200 may peel off. The Fresnel lens 200 of the fourth embodiment differs from that of the first embodiment in that it is trimmed into a rounded square.

FIG. 16 is a top view showing one configuration example of the Fresnel lens 200 according to the fourth embodiment of the present technology. The Fresnel lens 200 of the fourth embodiment differs from that of the first embodiment in that it is trimmed to form a rounded quadrangle, which is a quadrangle with rounded corners, when viewed from the optical axis direction.

At the four corners, the taper angle β of the Fresnel lens 200 is small and the interval between the ring zones is narrow, making it difficult to obtain effective information during fingerprint authentication. Therefore, even if the four corners are rounded, there is almost no adverse effect on the accuracy of authentication.

As illustrated in the figure, by forming a square with rounded corners, stress concentration on the four corners can be suppressed, and peeling resistance of the Fresnel lens 200 can be improved.

It should be noted that the second and third embodiments can be applied to the fourth embodiment.

Thus, according to the fourth embodiment of the present technology, the shape of the Fresnel lens 200 is a square with rounded corners, so it is possible to improve peeling resistance compared to the case of a rectangular shape.

<5. Fifth Embodiment>
In the first embodiment described above, the Fresnel lens 200 is formed before dicing, but it is also possible to form the Fresnel lens 200 for each chip after dicing. The Fresnel lens 200 of the fifth embodiment differs from that of the first embodiment in that the Fresnel lens 200 is formed for each chip after dicing.

FIG. 17 is a diagram showing an example of a method of manufacturing the Fresnel lens 200 up to discharging the lens material 620 according to the fifth embodiment of the present technology. The sensor substrate 610 is diced, and various circuits and elements are formed for each chip. Each chip functions as a solid-state imaging device 300 . After that, the steps in the figure are executed.

As illustrated in a in the figure, the manufacturing system forms a PF (Print Free) water-repellent film 640 around the effective area on the upper surface of the chip (the solid-state imaging device 300).

Next, as illustrated in b in the figure, the manufacturing system dispenses the lens material 620 onto the upper surface of the chip using the dispenser 650 .

As illustrated in c in the figure, the lens material 620 is rearranged in a self-organizing manner so that the surface energy is minimized.

FIG. 18 is a diagram showing an example of a method of manufacturing the Fresnel lens 200 up to releasing the transparent mold 630 according to the fifth embodiment of the present technology. The process shown in the figure is executed after the lens material 620 is discharged.

The manufacturing system presses the transparent mold 630 against the lens material 620 as illustrated in a in the figure.

Then, as illustrated in b in the figure, the manufacturing system irradiates light of a predetermined wavelength (ultraviolet rays, etc.) to cure the lens material 620 .

Subsequently, as illustrated in c in the figure, the manufacturing system releases the transparent mold 630 and performs various necessary processes.

As illustrated in FIGS. 17 and 18, by manufacturing the Fresnel lens 200 for each chip after dicing, it becomes unnecessary to form circuits such as pixels on the sensor substrate 610 before dicing.

FIG. 19 is a flow chart showing an example of a method for manufacturing the Fresnel lens 200 according to the fifth embodiment of the present technology. The manufacturing system forms a water-repellent film 640 on the top surface of the chip (step S911).

Next, the manufacturing system dispenses the lens material 620 onto the top surface of the chip using the dispenser 650 or the like (step S912), and embosses the transparent mold 630 (step S913). Then, the manufacturing system irradiates ultraviolet rays or the like to harden the lens material 620 (step S914). Subsequently, the manufacturing system releases the transparent mold 630 (step S915), performs various processes, and completes the manufacturing of the Fresnel lens 200. FIG. The steps shown in the figure are sequentially executed for each chip. Alternatively, the steps in the figure are executed in parallel for a plurality of chips.

Although the lens material 620 is supplied by the dispenser 650 in FIG. 17, the manufacturing method is not limited to this. As illustrated in FIG. 20, the lens material 620 can also be applied by spin coating or the like. In this case, after forming the water-repellent film 640 as illustrated in a of the figure, the manufacturing system applies a lens material 620 to the upper surface of the chip as illustrated in b of the same figure. The lens material 620 is rearranged in a self-organizing manner such that the surface energy is minimized, as illustrated at c in FIG. Also, the lens material 620 is automatically separated by the water-repellent film 640 . After that, the steps illustrated in FIG. 18 are performed.

It should be noted that the second, third and fourth embodiments can also be applied to the fifth embodiment.

As described above, according to the fifth embodiment of the present technology, since the Fresnel lens 200 is manufactured for each chip after dicing, there is no need to form pixels and the like before dicing.

<6. Example of application to moving objects>
The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure can be realized as a device mounted on any type of moving body such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility, airplanes, drones, ships, and robots. may

FIG. 21 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology according to the present disclosure can be applied.

A vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in FIG. 21, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside information detection unit 12030, an inside information detection unit 12040, and an integrated control unit 12050. Also, as the functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio/image output unit 12052, and an in-vehicle network I/F (interface) 12053 are illustrated.

The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the driving system control unit 12010 includes a driving force generator for generating driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, and a steering angle of the vehicle. It functions as a control device such as a steering mechanism to adjust and a brake device to generate braking force of the vehicle.

The body system control unit 12020 controls the operation of various devices equipped on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as headlamps, back lamps, brake lamps, winkers or fog lamps. In this case, the body system control unit 12020 can receive radio waves transmitted from a portable device that substitutes for a key or signals from various switches. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, etc. of the vehicle.

The vehicle exterior information detection unit 12030 detects information outside the vehicle in which the vehicle control system 12000 is installed. For example, the vehicle exterior information detection unit 12030 is connected with an imaging section 12031 . The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image of the exterior of the vehicle, and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing such as people, vehicles, obstacles, signs, or characters on the road surface based on the received image.

The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of received light. The imaging unit 12031 can output the electric signal as an image, and can also output it as distance measurement information. Also, the light received by the imaging unit 12031 may be visible light or non-visible light such as infrared rays.

The in-vehicle information detection unit 12040 detects in-vehicle information. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection section 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 detects the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041. It may be calculated, or it may be determined whether the driver is dozing off.

The microcomputer 12051 calculates control target values for the driving force generator, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and controls the drive system control unit. A control command can be output to 12010 . For example, the microcomputer 12051 realizes the functions of ADAS (Advanced Driver Assistance System) including collision avoidance or shock mitigation, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, or vehicle lane deviation warning. Cooperative control can be performed for the purpose of

In addition, the microcomputer 12051 controls the driving force generator, the steering mechanism, the braking device, etc. based on the information about the vehicle surroundings acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, so that the driver's Cooperative control can be performed for the purpose of autonomous driving, etc., in which vehicles autonomously travel without depending on operation.

Also, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the information detection unit 12030 outside the vehicle. For example, the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or the oncoming vehicle detected by the vehicle exterior information detection unit 12030, and performs cooperative control aimed at anti-glare such as switching from high beam to low beam. It can be carried out.

The audio/image output unit 12052 transmits at least one of audio and/or image output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle. In the example of FIG. 21, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are illustrated as output devices. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

FIG. 22 is a diagram showing an example of the installation position of the imaging unit 12031. FIG.

In FIG. 22, the imaging unit 12031 has

imaging units

12101, 12102, 12103, 12104, and 12105.

The

imaging units

12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose of the vehicle 12100, the side mirrors, the rear bumper, the back door, and the upper part of the windshield in the vehicle interior, for example. An image pickup unit 12101 provided in the front nose and an image pickup unit 12105 provided above the windshield in the passenger compartment mainly acquire images in front of the vehicle 12100 .

Imaging units

12102 and 12103 provided in the side mirrors mainly acquire side images of the vehicle 12100 . An imaging unit 12104 provided in the rear bumper or back door mainly acquires an image behind the vehicle 12100 . The imaging unit 12105 provided above the windshield in the passenger compartment is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.

Note that FIG. 22 shows an example of the imaging range of the imaging units 12101 to 12104. FIG. The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided in the front nose, the imaging ranges 12112 and 12113 indicate the imaging ranges of the

imaging units

12102 and 12103 provided in the side mirrors, respectively, and the imaging range 12114 The imaging range of an imaging unit 12104 provided on the rear bumper or back door is shown. For example, by superimposing the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 viewed from above can be obtained.

At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 determines the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and changes in this distance over time (relative velocity with respect to the vehicle 12100). , it is possible to extract, as the preceding vehicle, the closest three-dimensional object on the course of the vehicle 12100, which runs at a predetermined speed (for example, 0 km/h or more) in substantially the same direction as the vehicle 12100. can. Furthermore, the microcomputer 12051 can set the inter-vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including following stop control) and automatic acceleration control (including following start control). In this way, cooperative control can be performed for the purpose of automatic driving in which the vehicle runs autonomously without relying on the operation of the driver.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 converts three-dimensional object data related to three-dimensional objects to other three-dimensional objects such as motorcycles, ordinary vehicles, large vehicles, pedestrians, and utility poles. It can be classified and extracted and used for automatic avoidance of obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into those that are visible to the driver of the vehicle 12100 and those that are difficult to see. Then, the microcomputer 12051 judges the collision risk indicating the degree of danger of collision with each obstacle, and when the collision risk is equal to or higher than the set value and there is a possibility of collision, an audio speaker 12061 and a display unit 12062 are displayed. By outputting an alarm to the driver via the drive system control unit 12010 and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be performed.

At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not the pedestrian exists in the captured images of the imaging units 12101 to 12104 . Such recognition of a pedestrian is performed by, for example, a procedure for extracting feature points in images captured by the imaging units 12101 to 12104 as infrared cameras, and performing pattern matching processing on a series of feature points indicating the outline of an object to determine whether or not the pedestrian is a pedestrian. This is done by a procedure that determines When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 outputs a rectangular outline for emphasis to the recognized pedestrian. is superimposed on the display unit 12062 . Also, the audio/image output unit 12052 may control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 among the configurations described above. Specifically, for example, the solid-state imaging device 100 in FIG. 1 can be applied to the imaging unit 12031 . By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to obtain a captured image that is easier to see, thereby reducing driver fatigue.

It should be noted that the above-described embodiment shows an example for embodying the present technology, and the matters in the embodiment and the matters specifying the invention in the scope of claims have corresponding relationships. Similarly, the matters specifying the invention in the scope of claims and the matters in the embodiments of the present technology with the same names have corresponding relationships. However, the present technology is not limited to the embodiments, and can be embodied by various modifications to the embodiments without departing from the scope of the present technology.

It should be noted that the effects described in this specification are only examples and are not limited, and other effects may also occur.

Note that the present technology can also have the following configuration.
(1) a lens portion having one of both surfaces flat and the other of the two surfaces curved;
It is formed concentrically around the optical axis and each has a substantially triangular cross-section whose base is a line segment connecting two points on the curved surface. A Fresnel lens comprising a plurality of annular zones that become larger with increasing distance from the axis.
(2) The Fresnel lens according to (1), wherein the larger the half angle of view of the Fresnel lens, the higher the height from the base to the opposite vertex.
(3) Let h be the height, α be the half angle of view, β be the taper angle between one of the two sides of the substantially triangular shape other than the base and the optical axis, and T be the predetermined allowable value. The Fresnel lens according to (2) above, in which the following relational expression holds between α, β and T.
{h×sin(α+β)}/(cosβcosα)<T
(4) The Fresnel lens according to any one of (1) to (3), wherein the vertical distances of the plurality of ring zones are different from each other.
(5) the plurality of ring zones,
a plurality of inner ring zones whose radii do not exceed a predetermined value;
A plurality of outer ring zones having a radius larger than the predetermined value,
The plurality of inner ring zones have the same vertical distance,
The Fresnel lens according to any one of (1) to (3), wherein the plurality of outer annular zones have different vertical distances.
(6) the plurality of ring zones,
a pair of first ring zones adjacent to each other;
A pair of second ring zones adjacent to each other and having a larger radius than both of the pair of first ring zones,
The pair of first ring zones have the same vertical distance,
The pair of second ring zones have the same vertical distance,
The Fresnel lens according to any one of (1) to (3), wherein the pair of first ring zones and the pair of second ring zones have different vertical distances from each other.
(7) The Fresnel lens according to any one of (1) to (6), wherein the plurality of annular zones are formed by Fresneling a spherical lens.
(8) The Fresnel lens according to any one of (1) to (6), wherein the plurality of annular zones are formed by Fresneling an aspherical lens.
(9) The Fresnel lens according to any one of (1) to (8), which has negative optical power.
(10) The Fresnel lens according to any one of (1) to (8), which has positive optical power.
(11) The Fresnel lens according to any one of (1) to (10), wherein the Fresnel lens has a rectangular shape when viewed from the direction of the optical axis.
(12) The Fresnel lens according to any one of (1) to (10), wherein the shape of the Fresnel lens when viewed from the direction of the optical axis is a square with rounded corners.
(13) A substantially triangular shape formed concentrically around the optical axis with a lens portion having one flat surface on one side and a curved surface on the other side, and a line segment connecting two points on the curved surface as a base. a Fresnel lens comprising a plurality of annular zones each having a cross section of and the vertical distance from the plane to the opposite vertices of the base increases as the distance from the optical axis increases;
and a solid-state imaging device that generates image data by photoelectric conversion of light from the Fresnel lens.
(14) The electronic device according to (13), wherein a predetermined number of pixels are arranged in a portion of the image plane of the solid-state imaging device that faces the base.
(15) a lens material supply procedure for supplying a liquid lens material to a predetermined surface;
a lens portion having one of its two surfaces flat and the other of said two surfaces curved; an embossing step of pressing a mold against the lens material, each having a plurality of orbicular zones each having a vertical distance from the plane to the opposite vertices of the base that decreases with increasing distance from the optical axis;
and a curing step for curing said lens material.
(16) The manufacturing method according to (15), wherein the predetermined surface is a surface on a predetermined substrate before dicing.
(17) The manufacturing method according to (15), wherein the predetermined surface is a surface on a predetermined chip after dicing.
(18) the lens material is a photocurable resin;
the mold is transparent,
The manufacturing method according to any one of (15) to (17), wherein light of a predetermined wavelength is applied in the curing procedure.

REFERENCE SIGNS LIST 100 solid-state imaging device 200

fresnel lens

210, 631

ring zone

211, 212

ring zone

220, 632 lens section 300 solid-state image sensor 301 pixel chip 302 circuit chip 310

pixel

400, 402 cover glass 610 sensor substrate 620

lens material

630, 635 transparent Mold 640 Water-repellent film 650 Dispenser 700 Fingerprint authentication device 702 Processing unit 704 Display unit 900 Finger 904 Sample 12031 Imaging unit

Claims

a lens portion having one of both surfaces flat and the other of the two surfaces curved;
It is formed concentrically around the optical axis and each has a substantially triangular cross-section whose base is a line segment connecting two points on the curved surface. A Fresnel lens comprising a plurality of annular zones that become larger with increasing distance from the axis.
2. The Fresnel lens according to claim 1, wherein the larger the half angle of view of the Fresnel lens, the higher the height from the base to the opposite vertex.
Let h be the height, α be the half angle of view, β be the taper angle between one of the two sides of the substantially triangular shape other than the base and the optical axis, and T be the predetermined allowable value. 3. The Fresnel lens according to claim 2, wherein the following relational expression holds among α, β and T.
{h×sin(α+β)}/(cosβcosα)<T
The Fresnel lens according to claim 1, wherein the vertical distances of the plurality of annular zones are different from each other.
The plurality of annular zones are
a plurality of inner ring zones whose radii do not exceed a predetermined value;
A plurality of outer ring zones having a radius larger than the predetermined value,
The plurality of inner ring zones have the same vertical distance,
2. The Fresnel lens according to claim 1, wherein the plurality of outer ring zones have different vertical distances.
The plurality of annular zones are
a pair of first ring zones adjacent to each other;
A pair of second ring zones adjacent to each other and having a larger radius than both of the pair of first ring zones,
The pair of first ring zones have the same vertical distance,
The pair of second ring zones have the same vertical distance,
2. The Fresnel lens according to claim 1, wherein the pair of first ring zones and the pair of second ring zones have different vertical distances from each other.
The Fresnel lens according to claim 1, wherein the plurality of annular zones are formed by fresneling a spherical lens.
The Fresnel lens according to claim 1, wherein the plurality of annular zones are formed by Fresneling an aspherical lens.
The Fresnel lens according to claim 1, wherein said Fresnel lens has negative optical power.
The Fresnel lens according to claim 1, wherein said Fresnel lens has a positive optical power.
The Fresnel lens according to claim 1, wherein the Fresnel lens has a rectangular shape when viewed from the direction of the optical axis.
The Fresnel lens according to claim 1, wherein the shape of the Fresnel lens when viewed from the direction of the optical axis is a rounded quadrilateral.
a lens portion having one of its two surfaces flat and the other of said two surfaces curved; a Fresnel lens comprising a plurality of ring zones, each of which has a plurality of ring zones in which the vertical distance from the plane to the opposite vertex of the base increases as the distance from the optical axis increases;
and a solid-state imaging device that generates image data by photoelectric conversion of light from the Fresnel lens.
14. The electronic device according to claim 13, wherein a predetermined number of pixels are arranged on a portion of the image plane of the solid-state imaging device that faces the base.
a lens material supply procedure for supplying a liquid lens material to a predetermined surface;
a lens portion having one of its two surfaces flat and the other of said two surfaces curved; an embossing step of pressing a mold against the lens material, each having a plurality of orbicular zones each having a vertical distance from the plane to the opposite vertices of the base that decreases with increasing distance from the optical axis;
and a curing step for curing said lens material.
16. The manufacturing method according to claim 15, wherein said predetermined surface is a surface on a predetermined substrate before dicing.
16. The manufacturing method according to claim 15, wherein said predetermined surface is a surface on a predetermined chip after dicing.
The lens material is a photocurable resin,
the mold is transparent,
16. The manufacturing method according to claim 15, wherein light of a predetermined wavelength is applied in said curing step.