Image capturing module

An image capturing module includes a light filter, a meta-lens layer, and a photosensitive element. The light filter includes a light receiving surface and a light emitting surface opposite to each other. The meta-lens layer and the light filter are disposed side by side with each other. The meta-lens layer includes a light transmitting film and a plurality of microstructures. Each microstructure is arranged on the light transmitting film. The photosensitive element includes a photosensitive surface. The photosensitive surface faces to the meta-lens layer and the light emitting surface of the light filter, wherein the photosensitive surface has a plurality of pixels, and each pixel corresponds to each microstructure.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. § 119(a) to Patent Application No. 202110003486.4 filed in China on Jan. 4, 2021, the entire contents of which are hereby incorporated by reference.

BACKGROUND

Technical Field

The instant disclosure relates to an optical module, especially an image capturing module.

Related Art

With the rapid development of multimedia technology, many electronic products (e.g., smartphones, tablets, laptops, or digital cameras, etc.) are equipped with image capturing modules to support functions such as photography, online video, or facial recognition.

However, the lens of the currently known image capturing module is usually composed of a stack of multiple optical lenses (for example, each optical lens is a concave lens or a convex lens with a certain thickness), and the number of optical lens stacks will increase accordingly for the image capturing modules that require high image quality, resulting in the thickness and weight of the image capturing module cannot be further reduced.

SUMMARY

In view of the above, in an embodiment, an image capturing module is provided, including a light filter, a meta-lens layer, and a photosensitive element. The light filter includes the opposite light receiving surface and light emitting surface. The meta-lens layer and the light filter are disposed side by side with each other. The meta-lens layer includes a light transmitting film and a plurality of microstructures, and each microstructure is arranged on the light transmitting film. The photosensitive element includes a photosensitive surface, and the photosensitive surface faces to the meta-lens layer and the light emitting surface of the light filter, wherein the photosensitive surface has a plurality of pixels, and each pixel corresponds to each microstructure.

In sum, according to the image capturing module of the embodiment of the instant disclosure, through the photosensitive surface of the photosensitive element facing to the meta-lens layer and the light emitting surface of the light filter, and through the meta-lens layer having multiple microstructures respectively corresponding to multiple pixels of the photosensitive element, light can be guided by the multiple microstructures to respectively focus on the multiple pixels when the light passing through the light filter and the meta-lens layer, so as to sense and obtain a clear image, and the image capturing module can have no need to use optical lenses or reduce the usage number of optical lenses, so as to reduce the weight and thickness of the image capturing module and become lighter and thinner.

DETAILED DESCRIPTION

The following is a detailed description of various embodiments. However, these embodiments are merely used as examples and are not intended to limit the scope of the instant disclosure. In addition, drawings in the embodiments omit some components, to clearly show technical features of the instant disclosure. Identical reference numerals in all the drawings are used to represent identical or similar components.

FIG.1illustrates a cross-sectional view of the first embodiment of the image capturing module of the instant disclosure. As shown inFIG.1, the image capturing module1of the embodiment of the instant disclosure includes a light filter10, a meta-lens layer20, and a photosensitive element30, wherein the image capturing module1can be applied to various electronic products (e.g., smartphones, tablets, laptops, digital cameras, or video cameras, etc.) to obtain images of objects.

FIG.2illustrates a schematic diagram of the light path of the first embodiment of the image capturing module of the instant disclosure. As shown inFIG.1toFIG.2, the light filter10includes the opposite light receiving surface11and light emitting surface12. In some embodiments, the light filter10is a single-layer or multi-layer body made of light transmitting material (such as transparent plastic or glass) and can filter out unwanted light. For example, when external light (such as light L1) enters the interior of the filter10from the light receiving surface11, the light filter10can filter out the light of the specific wavelength in the light L1(such as ultraviolet light, infrared light, or visible light), such that the light of other wavelengths (such as light L2) can pass through the light emitting surface12to achieve a light filtering effect.

As shown inFIG.1, the meta-lens layer20and the light filter10are disposed side by side with each other. The aforementioned meta-lens layer20includes a light transmitting film21and a plurality of microstructures22, and each microstructure22is arranged on the light transmitting film21. The meta-lens layer20can be made of metamaterials, wherein the metamaterials are artificial materials with special properties, and the meta-lens layer20can arbitrarily control the propagation path of light through the design or arrangement of each microstructure22on the light transmitting film21.

As shown inFIG.1, the light transmitting film21of the meta-lens layer20can be a thin film or sheet made of light transmitting material. For example, the light transmitting material may be selected from a group of dielectric materials consisting of indium tin oxide (ITO), aluminum-doped zinc oxide (Al:ZnO; AZO), Ga-doped zinc oxide (Ga:ZnO; GZO), magnesium fluoride (MgF2), hafnium oxide (HfO2), silicon nitride (Si3N4), silicon dioxide (SiO2), and aluminum oxide (Al2O3). In some embodiments, the thickness of the light transmitting film21may be between 5 μm and 1000 μm. However, the light transmitting material and the thickness of the light transmitting film21are only for example and are not limited thereto in fact.

As shown inFIG.1, each microstructure22of the meta-lens layer20may be an artificial structure at nanometer order, having the ability to manipulate light characteristics under a scale much smaller than the wavelength. Specifically, by changing the parameters of each microstructure22, for example, the shape, arrangement manner to each other, size distribution, etc. of each microstructure22, the manipulation of the mode of light travel is achieved, thereby changing the effective refractive index (Neff) of the light.

As shown inFIG.1, the plurality of microstructures22may be transparent materials, such as gallium nitride (GaN), gallium phosphide (GaP), aluminum arsenide (AlAs), silicon (Si), or silicon oxide (SiO2) and so on. The plurality of microstructures22may also be metal materials, such as aluminum, silver, copper, gold or rhodium and so on. The plurality of microstructures22may be formed on the light transmitting film21by conventional means such as etching, photolithography, nanoimprint lithography, or lithography, thus the details are not repeated here.

As shown inFIG.1toFIG.2, a distance d is maintained between the photosensitive element30and the meta-lens layer20. The photosensitive element30includes a photosensitive surface31, and the photosensitive surface31faces to the light emitting surface12of the light filter10, such that the light L2emitted from the light emitting surface12can transmit to the photosensitive surface31of the photosensitive element30. For example, as shown inFIG.1, in this embodiment, the image capturing module1has a circular support13and a circuit board50. The circular support13has a central through hole131. The light filter10and the meta-lens layer20are fixed to the circular support13and correspond to the central through hole131. The circuit board50is located in the circular support13. The photosensitive element30is fixed on the circuit board50and does not contact the light filter10and meta-lens layer20, such that the photosensitive element30and the meta-lens layer20are kept at a distance d. Furthermore, the photosensitive element30is electrically connected to the circuit board50through a wire40. Therefore, after the photosensitive surface31of the photosensitive element30has received the light and converted the light signal into an electrical signal, the photosensitive element30can transmit the electrical signal to the circuit board50to store image information.

In some embodiments, the photosensitive element30may be a charge-coupled device (CCD), a complementary metal-oxide semiconductor (CMOS), or a CMOS active pixel sensor. In this embodiment, the photosensitive surface31of the photosensitive element30has a plurality of pixels P configured to sensitize to obtain images, and the plurality of pixels P respectively correspond to the plurality of microstructures22. For example, when a pixel P is a visible light sensing pixel, a microstructure22can be designed corresponding to the visible light sensing pixel, such that external light can be guided by the microstructure22to focus on the visible light sensing pixel during the process of passing through the meta-lens layer20, or when a pixel P is an infrared light sensing pixel, a microstructure22can be designed corresponding to the infrared light sensing pixel, such that external light can be guided by the microstructure22to focus on the infrared light sensing pixel during the process of passing through the meta-lens layer20.

In sum, according to the image capturing module1of the embodiments of the instant disclosure, through the photosensitive surface31of the photosensitive element30facing to the meta-lens layer20and the light emitting surface12of the light filter10, and through the meta-lens layer20having multiple microstructures22respectively corresponding to multiple pixels P of the photosensitive element30, external light can be guided by the multiple microstructures22to focus on the multiple pixels P when the external light passing through the light filter10and the meta-lens layer20, so as to sense and obtain a clear image, and the image capturing module1can have no need to use optical lenses or reduce the usage number of optical lenses, so as to reduce the weight and thickness of the image capturing module1and become lighter and thinner.

In some embodiments, the photosensitive element30may be an RGB-IR photosensitive element, an RGB photosensitive element, or IR photosensitive element. The multiple microstructures22of the meta-lens layer20can be designed according to different types of the photosensitive element30, which are respectively described in conjunction with the drawing as follows. As shown inFIG.1toFIG.2, in the first embodiment, the light filter10of the image capturing module1is located between the meta-lens layer20and the photosensitive surface31of the photosensitive element30. For example, the photosensitive element30of the image capturing module1could be an RGB-IR photosensitive element. The photosensitive surface31of the photosensitive element30has multiple pixels P. The multiple pixels P include multiple visible light sensing pixels P2and multiple infrared light sensing pixels P1. The multiple visible light sensing pixels P2include multiple red sensing pixels R, multiple green sensing pixels G, and multiple blue sensing pixels B. The meta-lens layer20of the image capturing module is joined between the light filter10and the circular support13. The multiple microstructures22of the meta-lens layer20include at least one first microstructure221and at least one second microstructure222. In this embodiment, the multiple microstructures22include multiple first microstructures221and multiple second microstructures222. The multiple first microstructures221respectively correspond to the multiple visible light sensing pixels P2. The multiple second microstructures222respectively correspond to the multiple infrared light sensing pixels P1. Each first microstructure221is different from each second microstructure222. Furthermore, each of the first microstructures221may be the same or different from each other.

For example, in this embodiment, since the wavelengths of infrared light and visible light are different and focus positions are also different, through different microstructures22of the meta-lens layer20(such as multiple first microstructures221and multiple second microstructures222), wherein the structures, shapes, or arrangements of the multiple first microstructures221are designed corresponding to the infrared light, and the structures, shapes, or arrangements of the multiple second microstructures222are designed corresponding to the visible light, such that the infrared light and the visible light are respectively guided by the multiple first microstructures221and multiple second microstructures222to respectively focus on each visible light sensing pixel P2and each infrared light sensing pixel P1, avoiding the image capturing module1emerging the phase delay problem.

Please again refer toFIG.2. Specifically, when external light L1enters the meta-lens layer20and passes through the light transmitting film21and each microstructure22of the meta-lens layer20, the external light L1can be guided by the multiple first microstructures221and multiple second microstructures222to converge along the direction from the light receiving surface11of the light filter10toward the light emitting surface12(such as light L2), and finally, respectively focus on each visible light sensing pixel P2and each infrared light sensing pixel P1, since each first microstructure221and each second microstructure222respectively correspond to each visible light sensing pixel P2and each infrared light sensing pixel P1(e.g., the shape and arrangement of each first microstructure221correspond to each visible light sensing pixel P2, and the shape and arrangement of each second microstructure222correspond to each infrared light sensing pixel P1).

FIG.3illustrates a cross-sectional view of a second embodiment of the image capturing module of the instant disclosure, andFIG.4illustrates a schematic diagram of the light path of the second embodiment of the image capturing module of the instant disclosure. Please refer toFIG.3andFIG.4. The difference between the second embodiment and the first embodiment is that the photosensitive element30aof the image capturing module1ais an RGB photosensitive element in the second embodiment. The multiple pixels P on the photosensitive surface31aof the photosensitive element30ainclude multiple visible light sensing pixels P2. The structures, arrangements, or shapes of the multiple microstructures22aof the meta-lens layer20amay be similar to the structures, arrangements, or shapes of the multiple first microstructures221described above. Therefore, when external light L1enters the meta-lens layer20aand passes through the light transmitting film21and each microstructure22aof the meta-lens layer20a, the external light L1can be guided by the multiple microstructures22ato converge along the direction from the light receiving surface11of the light filter10toward the light emitting surface12(such as light L2), and finally, respectively focus on each visible light sensing pixel P2, since each microstructure22acorresponds to each visible light sensing pixel P2.

As mentioned above, in some embodiments, the photosensitive element30amay also be an IR photosensitive element. The multiple pixels P on the photosensitive surface31aof the photosensitive element30ainclude multiple infrared light sensing pixels P1, and the structures, arrangements, or shapes of the multiple microstructures22aof the meta-lens layer20amay be similar to the structures, arrangements, or shapes of the multiple second microstructures222described above. Therefore, when external light L1enters the meta-lens layer20aand passes through the light transmitting film21and each microstructure22aof the meta-lens layer20a, the external light L1can be guided by the multiple microstructures22ato converge along the direction from the light receiving surface11of the light filter10toward the light emitting surface12, and finally, respectively focus on each infrared light sensing pixels P1, since each microstructure22acorresponds to infrared light sensing pixels P1.

FIG.5illustrates a cross-sectional view of a third embodiment of the image capturing module of the instant disclosure. In the third embodiment, the arrangement order of the meta-lens layer20band light filter10is different from that of the first embodiment. As shown inFIG.5, in this embodiment, the meta-lens layer20bof the image capturing module1bis located between the light emitting surface12of the light filter10and the photosensitive surface31bof the photosensitive element30b. Therefore, each first microstructure221band each second microstructure222bof the multiple microstructures22bon the meta-lens layer20bof this embodiment are different from each first microstructure221and each second microstructure222of the multiple microstructures22on the meta-lens layer20of the first embodiment.

As mentioned above, in this embodiment, for example, since external light passes through light filter10before passing through the meta-lens layer20b, the travel path of the light is different from that of the first embodiment. Therefore, the structures, arrangements, or shapes of each first microstructure221band each second microstructure222bof this embodiment are different from each first microstructure221and each second microstructure222of the first embodiment, such that each first microstructure221band each second microstructure222brespectively correspond to each visible light sensing pixel P2and each infrared light sensing pixel P1, thereby the external light can be guided by the multiple first microstructures221band multiple second microstructures222bto respectively converge along the direction from the meta-lens layer20btoward each pixel P, and finally, respectively focus on each visible light sensing pixel P2and each infrared light sensing pixel P1.

As mentioned above, as in the second embodiment, the photosensitive element30bmay also be an RGB photosensitive element or an IR photosensitive element in the third embodiment, and the external light can respectively focus on each visible light sensing pixel P2or each infrared light sensing pixel P1through the different configuration of microstructures22b.

The prior art often requires multiple optical lenses to focus external light on multiple pixels on the photosensitive element to sense and obtain a clear image. According to the image capturing module1/1a/1b, through the meta-lens layer20/20a/20bhaving multiple microstructures22/22a/22brespectively corresponding to multiple pixels P of photosensitive element30/30a/30b, external light can be guided by the multiple microstructures22/22a/22bto respectively focus on the multiple pixels P when the external light passing through the light filter10and the meta-lens layer20/20a/20b, so as to sense and obtain a clear image. Therefore, the image capturing module1/1a/1bcan have no need to use optical lenses to reduce the weight and thickness of the image capturing module1/1a/1band become lighter and thinner.

In some embodiments, the aforementioned embodiments may also be used with general optical lenses, as shown inFIG.6, whereinFIG.6illustrates a cross-sectional view of a fourth embodiment of the image capturing module of the instant disclosure. In this embodiment, the image capturing module1cfurther includes at least one lens60. The light filter10and the meta-lens layer20cof the image capturing module1care located between the at least one lens60and the photosensitive element30c. For example, in the fourth embodiment, the light filter10of the image capturing module1cis located between the meta-lens layer20cand the photosensitive surface31cof the photosensitive element30c, and the meta-lens layer20cis located between the light receiving surface11of the light filter10and the at least one lens60.

As mentioned above, for example, the image capturing module1chas a circular support13a, multiple lenses60arranged side by side (here are four lenses60, but this is not limited thereto), and a circuit board50. For example, in this embodiment, four lenses60are fixed to the circular support13athrough threads and are arranged side by side with the meta-lens layer20c. Compared with the aforementioned first embodiment, since this embodiment is further equipped with multiple lenses60, each first microstructure221cand each second microstructure222cof multiple microstructures22con the meta-lens layer20cof this embodiment are different from each first microstructure221and each second microstructure222of multiple microstructures22on the meta-lens layer20of the first embodiment.

As mentioned above, for example, in this embodiment, since external light passes through multiple lenses60before passing through the meta-lens layer20c, the travel path of the light is different from that of the first embodiment. Therefore, the structures, arrangements, or shapes of each first microstructure221cand each second microstructure222cof this embodiment are different from each first microstructure221and each second microstructure222of the first embodiment, such that each first microstructure221cand each second microstructure222crespectively correspond to each visible light sensing pixel P2and each infrared light sensing pixel P1, thereby the external light can be guided by the multiple first microstructures221cand multiple second microstructures222cto respectively converge along the direction from the light receiving surface11of the light filter10toward the light emitting surface12, and finally, respectively focus on each visible light sensing pixel P2and each infrared light sensing pixel P1.

As mentioned above, in other embodiments, the photosensitive element30cmay also be an RGB photosensitive element or an IR photosensitive element, and the external light can respectively focus on each visible light sensing pixel P2or each infrared light sensing pixel P1through the different configuration of microstructures22c, thus the details are not repeated here.

FIG.7illustrates a cross-sectional view of a fifth embodiment of the image capturing module of the instant disclosure. Please refer toFIG.7. In the fifth embodiment, the arrangement order of the meta-lens layer20dand light filter10is different from that of the fourth embodiment. As shown inFIG.7, in this embodiment, the meta-lens layer20dof the image capturing module1dis located between the light emitting surface12of the light filter10and the photosensitive surface31dof the photosensitive element30d. Therefore, each first microstructure221dand each second microstructure222dof the multiple microstructures22don the meta-lens layer20dof this embodiment are different from each first microstructure221cand each second microstructure222cof the multiple microstructures22con the meta-lens layer20cof the fourth embodiment.

As mentioned above, in this embodiment, for example, since external light passes through multiple lenses60and then passes through the light filter10before passing through the meta-lens layer20d, the travel path of the light is different from that of the fourth embodiment. Therefore, the structures, arrangements, or shapes of each first microstructure221dand each second microstructure222dof this embodiment are different from each first microstructure221cand each second microstructure222cof the fourth embodiment, such that each first microstructure221dand each second microstructure222drespectively correspond to each visible light sensing pixel P2and each infrared light sensing pixel P1, thereby the external light can be guided by the multiple first microstructures221dand multiple second microstructures222dto respectively converge along the direction from the meta-lens layer20dtoward each pixel P, and finally, respectively focus on each visible light sensing pixel P2and each infrared light sensing pixel P1. As in the fourth embodiment, the photosensitive element30dmay also be an RGB photosensitive element or an IR photosensitive element in the fifth embodiment, and the external light can respectively focus on each visible light sensing pixel P2or each infrared light sensing pixel P1through the different configuration of microstructures22d.

According to the image capturing module1c/1d, through the meta-lens layer20c/20dhaving multiple microstructures22c/22drespectively corresponding to multiple pixels P of photosensitive element30c/30d, external light can be guided by the multiple microstructures22c/22dto respectively focus on the multiple pixels P when the external light passing through the light filter10and the meta-lens layer20c/20d, so as to sense and obtain a clear image. Therefore, the image capturing module1c/1dcan reduce the usage number of optical lenses60to reduce the weight and thickness of the image capturing module1c/1sand become lighter and thinner. For example, an image capturing module fabricated by the prior art requires multiple optical lenses to achieve high-quality image level. The image capturing module1c/1dof the embodiments of the instant disclosure can reduce part of the usage number of optical lenses used in the prior art by the meta-lens layer20c/20d, such that the image capturing module1c/1dstill can achieve the requirement of capturing high-quality images while reducing the number of optical lenses.