TWI422894B - Wafer level optical imaging apparatus - Google Patents

Description

Wafer level optical camera

The present invention relates to a wafer level module, and more particularly to a wafer level optical camera device for providing a shadowing function and avoiding stray light.

Wafer level optical technology uses semiconductor processes to fabricate wafer-level small optical devices, such as lens modules or camera modules. This wafer level optical technology can be applied to mobile or handheld electronic devices.

As shown in the first figure, conventional optical imaging device 10 is typically covered with a lens mask 12 for protecting optical imaging device 10 and providing the desired aperture. However, for wafer level processes or chip scale packages, it is difficult to make such small masks, and even more difficult to cut wafers to get individual modules.

Furthermore, whether it is a wafer level optical imaging device or a conventional size optical imaging device, it is generally easy to generate stray light in a field of view, thereby degrading image quality. However, there is no effective mechanism to solve this problem.

In view of the fact that conventional optical imaging devices cannot effectively solve stray light problems and cannot provide lens masks economically, it is urgent to propose a novel mechanism to solve the above problems.

In view of the above, one of the objects of embodiments of the present invention is to provide a wafer level optical imaging device that not only provides a mask function but also prevents generation of stray light.

According to an embodiment of the invention, a wafer level optical imaging device includes an imaging unit and a cover substrate covering the imaging unit. The camera unit includes a lens substrate having a lens formed on the surface thereof, an image sensor for converting light passing through the lens substrate into an electrical signal, and a plurality of spacers, and a portion of the spacer is fixed to the image sensor Between the lens substrate and the lens substrate, the remaining spacers are fixed between the lens substrate and the cover substrate. The opaque upper shielding layer is formed on the upper surface of the cover substrate, and the opaque lower shielding layer is formed on the lower surface of the cover substrate. According to one of the features of the embodiment, the upper and lower shielding layers respectively have upper and lower openings, and the size of the upper opening is larger than the size of the lower opening. Thereby, the upper opening and the lower opening together define a field of view for limiting the incident light reaching the lens substrate and the image sensor through the covering substrate.

10‧‧‧Optical camera

12‧‧‧ lens mask

20‧‧‧ camera unit

200‧‧‧Optical components

201‧‧‧ lens substrate

201A‧‧ lens

203‧‧‧Image sensor

205‧‧‧ spacers

22‧‧‧ Covering substrate

Upper surface of 220‧‧‧ (covering the substrate)

221‧‧‧Upper cover

221A‧‧‧(top) round opening

222‧‧‧ (covering the lower surface of the substrate)

223‧‧‧Under the cover layer

223A‧‧‧(bottom) round opening

24‧‧ ‧Field of view

The first figure shows a conventional optical camera device covered with a lens mask.

The second figure shows a cross-sectional view of a wafer level optical imaging device according to an embodiment of the present invention.

The third figure shows an expanded view of the cover substrate, the upper shielding layer, and the lower shielding layer in the second figure.

The illustrative embodiment shown in the fourth figure shows the details of the camera unit of the wafer level camera module.

The second figure shows a cross section of a wafer level optical imaging device according to an embodiment of the present invention. Figure. Although this embodiment exemplifies a wafer level camera, the present embodiment is also applicable to other optical imaging devices.

In the embodiment, the wafer level optical imaging device mainly includes an imaging unit 20 and a cover substrate 22. Wherein, the imaging unit 20 includes at least an optical element 200 (for example, a lens), as indicated by a broken line ellipse in the figure. The cover substrate 22 may be, but is not limited to, a glass plate.

According to the present embodiment, the upper surface 220 and the lower surface 222 of the cover substrate 22 are partially covered by the opaque upper shielding layer 221 and the lower shielding layer 223, respectively. In the present specification, "upper" refers to the light source, and "lower" refers to the imaging unit 20. The third figure shows an expanded view of the cover substrate 22, the upper shielding layer 221, and the lower shielding layer 223. The upper shielding layer 221 has a (upper) circular opening 221A, and the lower shielding layer 223 has a (lower) circular opening 223A. In other embodiments, the aperture pattern is not limited to a circular aperture.

According to one of the features of the embodiment, the size (e.g., diameter) of the upper opening 221A is larger than the size of the lower opening 223A. Thereby, as shown in the second figure, the (larger) upper opening 221A and the (smaller) lower opening 223A collectively define a field of view 24 for confining through the cover substrate 22. The incident light rays reaching the imaging unit 20.

In accordance with the present embodiment, the field of view 24 is formed to allow the desired light to pass through while blocking other unwanted light (e.g., light that is greater than the angle defined by field of view 24) from entering the camera unit 20. Thereby, the stray light in the imaging unit 20 can be largely reduced or even disappeared. In other words, the cover substrate 22 with the upper/lower shielding layers 221/223 can serve as a mask to prevent the generation of stray light. Furthermore, the cover substrate 22 can also be used to protect the camera unit 20 from damage. Furthermore, in the embodiment, the upper shielding layer 221 and the lower shielding layer One or both of layers 223 may also be provided as an aperture.

The illustrative embodiment shown in the fourth figure shows details of the camera unit 20 of the wafer level camera module. To simplify the drawing, only one of the modules is shown. In the illustrated embodiment, the imaging unit 20 mainly includes a lens substrate 201 and an image sensor 203. One or more lenses 201A are formed on the surface of the lens substrate 201, and the image sensor 203 may be a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD). The image sensor 203 is used to convert light passing through the lens substrate 201 into an electrical signal. Furthermore, a spacer 205 is fixed (for example, using an adhesive) between the image sensor 203 and the lens substrate 201, and is fixed between the lens substrate 201 and the cover substrate 22. In the present embodiment, the upper shielding layer 221 and the lower shielding layer 223 are respectively formed or deposited on the surface of the cover substrate 22, for example, using an evaporation method or a sputtering method. The deposited material can be, but is not limited to, chromium oxide. After the entire wafer is slicing, multiple wafer level camera modules are available.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; all other equivalent changes or modifications which are not departing from the spirit of the invention should be included in the following Within the scope of the patent application.

20‧‧‧ camera unit

200‧‧‧Optical components

22‧‧‧ Covering substrate

Upper surface of 220‧‧‧ (covering the substrate)

221‧‧‧Upper cover

222‧‧‧ (covering the lower surface of the substrate)

223‧‧‧Under the cover layer

24‧‧ ‧Field of view

Claims (17)

A wafer level optical imaging device comprising: an imaging unit; a cover substrate for covering the imaging unit; an upper shielding layer formed on an upper surface of the cover substrate; and a lower shielding layer formed on the cover substrate a lower surface; wherein the upper shielding layer is opaque and has an upper opening, and the lower shielding layer is opaque and has a lower opening, and the upper opening and the lower opening together define a field of view (field) Of view) for limiting incident light reaching the camera unit through the cover substrate. The wafer level optical imaging device of claim 1, wherein the imaging unit comprises an optical element. The wafer level optical imaging device of claim 1, wherein the cover substrate comprises a glass plate. The wafer level optical imaging device of claim 1, wherein the size of the upper opening is larger than the size of the lower opening. The wafer level optical imaging device of claim 1, wherein the upper opening is circular and the lower opening is circular. The wafer level optical imaging device according to claim 1, wherein the image pickup unit comprises a lens substrate having a lens formed on a surface thereof. The wafer level optical camera device of claim 6, wherein the image capturing unit further comprises an image sensor for converting light passing through the lens substrate into an electrical signal. The wafer level optical imaging device of claim 7, wherein the image capturing unit further comprises a plurality of spacers, and the spacer is fixed between the image sensor and the lens substrate. The remaining spacer is fixed between the lens substrate and the cover substrate. The wafer level optical imaging device of claim 7, wherein the image sensor comprises a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD). The wafer level optical imaging device of claim 1, wherein the upper shielding layer is deposited on the upper surface of the cover substrate by evaporation or sputtering, and the lower shielding layer is evaporated by evaporation. Or deposited on the lower surface of the cover substrate by a sputtering method. The wafer level optical imaging device of claim 10, wherein the upper shielding layer and the lower shielding layer comprise chromium oxide. A wafer level optical imaging device comprising: a lens substrate having a lens formed on a surface thereof; an image sensor for converting light passing through the lens substrate into an electrical signal; and a cover substrate for covering the camera unit a plurality of spacers, a portion of the spacer is fixed between the image sensor and the lens substrate, and the other spacer is fixed between the lens substrate and the cover substrate; an opaque upper shielding layer Forming on an upper surface of the cover substrate; and an opaque lower shielding layer formed on a lower surface of the cover substrate; wherein the upper shielding layer has an upper opening, and the lower shielding layer has a lower opening, The size of the upper opening is larger than the size of the lower opening, wherein the upper opening and the lower opening together define a field of view for limiting access to the lens substrate through the cover substrate and The incident light of the image sensor. The wafer level optical imaging device of claim 12, wherein the cover substrate comprises a glass plate. The wafer level optical imaging device of claim 12, wherein the upper opening is circular and the lower opening is circular. The wafer level optical imaging device of claim 12, wherein the image sensor comprises a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD). The wafer level optical imaging device of claim 12, wherein the upper shielding layer is deposited on the upper surface of the cover substrate by evaporation or sputtering, and the lower shielding layer is evaporated by evaporation. Or deposited on the lower surface of the cover substrate by a sputtering method. The wafer level optical imaging device of claim 16, wherein the upper shielding layer and the lower shielding layer comprise chromium oxide.