Optical sensor module and packaging method thereof

An optical sensor module and a packaging method thereof are disclosed, wherein the optical sensor module comprises a substrate having a light sensing element; and a housing made of a transparent material. The housing is connected to the substrate and covers the light sensing element. The housing has a light-receiving area facing the light sensing element, and the inner surface of the housing toward the substrate is provided with a light-shielding coating in a portion outside of the light-receiving area. In this way, optical components such as the light sensor can be effectively protected, and still retain the effect of avoiding noise light interference with the light sensor module.

FIELD OF THE INVENTION

The present application generally relates to an optical sensor module, and particularly to an optical sensor module having a light-sensing device and the packaging method thereof.

BACKGROUND OF THE INVENTION

Optical sensing devices, for example, CMOS image sensors (CIS), proximity sensors (PS), and ambient light sensors, are applied extensively in mobile devices such as cellular phones or other consumer electronic devices. These optical sensing devices require light-sensing devices. In particular, proximity sensors further require light-emitting devices.

FIG.1shows an optical sensor9according to the prior art, in which a light-sensing device92and a light-emitting device93are disposed on a substrate91. In general, the light-sensing device92is integrated in the IC chip. To protect optical elements such as the chip of the light-sensing device92and the emitter of the light-emitting device93, according to the prior art, the light-sensing device92and the light-emitting device93will be sealed in a transparent plastic material94. For example, a liquid transparent glue material (such as resin) can be injected into a mold. After solidification, the mold is removed. Then the light-sensing device92and the light-emitting device93are covered in the transparent plastic material94.

To avoid interference on the light-sensing device92by the noise light or the light emitted from the light-emitting device93, the packaging method according to the prior art adopts an opaque metal or plastic lid as the covering device. The packaging method for the light sensor9is in batch. In other words, on the whole circuit board with multiple substrates91, the transparent plastic material94is first cut for forming grooves941surrounding or even passing the substrate91. Next, opaque lids95are bonded to the substrates91for covering and jointing with the transparent plastic material94. This assembly method is complicated. The cutting process might even damage the structure. Consequently, the groove area must be free from any wire or circuit structure. This method will occupy the wire bonding space and hence disadvantageous to package miniaturization.

In addition, as the devices shrink, the requirements for the performance of optical sensor9is increased. Thereby, optical structures on the optical paths of the light-sensing device92and the light-emitting device93are required to adjust their optical properties. For example, since the opaque lid95cannot be used to manufacture lenses, lenses942are manufactured on the transparent plastic material94according to the prior art. Since the transparent plastic material94needs to envelop the light-sensing device92and the light-emitting device93, additional assembly and cuts are unavoidable, leading to limitations on lens design and increased difficulty in fabrication. Furthermore, although the optical structures such as lenses can be manufactured as independent modules (for example, use a transparent material to manufacture additional tube lenses as the optical structures) and bonded to the opaque lid95, this method undoubtedly increases component number and assembly steps.

In the trend of device miniaturization, the lids, grooves, or other optical structures require high precision for assembly and forming optical sensor units with excellent performance. Accordingly, the process complexity is increased significantly and the production yield can be decreased. It is urged to improve the situation.

SUMMARY OF THE INVENTION

An objective of the present application is to provide an optical sensor module and the packaging method thereof. By using a transparent material for manufacturing the housing and including a shading coating layer on the housing, the light-sensing device or the light-emitting device can be protected effectively, as well as avoiding interference on the light sensor module by noise light. Thereby, the packaging process can be simplified; the production yield can be increased; the packaging design can be miniaturized; the design flexibility can be improved; and the manufacturing difficulty of optical structures can be reduced.

According to an embodiment of the present application, an optical sensor module is disclosed. The optical sensor module comprises a substrate and a housing made of a transparent material. The substrate includes a light-sensing device. The housing is connected to the substrate and covers the light-sensing device. The housing includes a light-receiving region facing the light-sensing device. The housing includes a shading coating layer on the inner surface facing the substrate and outside the light-receiving region.

According to an embodiment of the present application, a packaging method for an optical sensor module is disclosed. The method comprises: disposing optical elements including a light-sensing device on a substrate; disposing a shading coating layer on the surface of a housing made of a transparent material; and connecting and fixing the housing on the substrate.

DETAILED DESCRIPTION OF THE INVENTION

In order to make the structure and characteristics as well as the effectiveness of the present application to be further understood and recognized, a detailed description of the present application is provided as follows along with embodiments and accompanying figures.

First, please refer toFIG.2andFIG.3.FIG.2shows a cross-sectional view of the optical sensor module according to the first embodiment of the present application;FIG.3shows a stereoscopic view of the first embodiment. The optical sensor module1according to the first embodiment comprises a substrate11, a light-sensing device12, and a housing13. The substrate11can be any material suitable for optical packaging, for example, a copper substrate, a ceramic substrate, a lead frame, a resin substrate, or a printed circuit board. The light-sensing device12can be formed by an IC chip. In addition, the light-sensing device12is disposed on the substrate11. In general, the light-sensing device12can be fixed to the blank substrate11by die attaching. Depending on the type of the optical sensor module1, the light-sensing device12can include one or multiple light-sensing units121. When the light-sensing device12includes multiple light-sensing units121, a light-sensing matrix can be formed. Nonetheless, the present application is not limited to the embodiment. The housing13is made of a transparent material, which allows the light with specific wavelengths or any wavelength to pass through. The housing13includes one or multiple contact surface13athat allows the housing13to connect to the substrate11along a vertical direction X. The housing13can be connected and fixed to the substrate11by gluing or high-temperature welding. The housing13will cover the light-sensing device12after connecting to the substrate11.

The housing13includes a light-receiving region131facing the light-sensing device12along the vertical direction X. The housing13also includes a shading coating layer14on the inner surface13bfacing the substrate11and outside the light-receiving region131. The shading coating layer14can be formed by spraying or coating using a shading material, which can be ink, photoresist, or black epoxy. Besides, the transmittance of the shading material for specific or all wavelengths is preferably less than 20%. Since the shading coating layer14will not cover the light-receiving region131of the housing13, the light-receiving path of the light-sensing device12will not be shaded.

Please refer toFIG.4AandFIG.4B.FIG.4Ashows a perspective view of the optical sensor module after assembly according to the first embodiment of the present application;FIG.4Bshows a cross-sectional view of the first embodiment after assembly. After the housing13is connected to the substrate11, an compartment R1will be formed between the substrate11and the inner surface13bof the housing13. The light-sensing device12is just located in the compartment R1. The housing13is made of a transparent material. Thereby, it is not necessary to drill a hole for light passage. That is to say, the compartment R1can be hermetic. Consequently, although no transparent plastic material is used to seal the light-sensing device12according to the present embodiment, the light-sensing device12can still be protected by the housing13by blocking external moist, dust, or dirt, which might damage the light-sensing device12once contacting. In fact, not only the light-sensing device12is protected by the housing13, the pads111for connecting electrically to the light-sensing device12on the substrate11and the wiring between the substrate11and the light-sensing device12can both be protected by the housing13as well.

In the optical sensor module1according to the first embodiment of the present application, no transparent plastic material94is required to cover the light-sensing device92like in the prior art. Consequently, no cutting step for the transparent plastic material94is required. According to the first embodiment, the housing13is made of a transparent material. It is not necessary to drill a hole for light passage. Thereby, once the housing13is connected on the substrate11, the excellent protection is formed. Moreover, by including the shading coating layer14on the inner surface13bof the housing13, the interference of noise light on the light-sensing device12can be avoided.

Please refer toFIG.5, which shows a flowchart of the packaging method for the optical sensor module according to the first embodiment of the present application. The packaging method comprises:

Disposing the optical element on the substrate11, in which the optical element includes the light-sensing device12according to the first embodiment;

Disposing the shading coating layer14on the surface of the housing13made of a transparent material; and

Connecting and fixing the housing on the substrate11.

Thereby, according to the packaging method for the optical sensor module according to the first embodiment of the present application, only the shading coating layer14is required on the inner surface13bof the housing13before connecting the housing13to the substrate11. The complicated process of cutting the transparent plastic material94according to the prior art can be omitted completely. In addition, the effective area for disposing circuit structures is further extended, which is beneficial to the miniaturization of packaging design.

In the following, various embodiments of the optical sensor module according to the present application will be described in detail.

Please refer again toFIG.2,FIG.3, andFIG.4B. According to the first embodiment, if the optical sensor module1is used as a proximity sensor, a depth sensor, or a specific image sensor (such of a time-of-flight distance sensor), in addition to the light-sensing device12, the optical element used by the optical sensor module1generally further needs a light-emitting device15, which can be a light-emitting diode or a laser emitter with wavelengths in the infrared band (such 940 nm) or the visible-light band (such as 550 nm). The light-emitting device15is also disposed on the substrate11. It can be fixed on the blank substrate11along with the light-sensing device12using the attaching method as described above. After the housing13is connected to the substrate11, it covers the light-sensing device12and the light-emitting device15. The housing13includes a light-emitting region132facing the light-emitting device15along the vertical direction X. The housing13also includes a shading coating layer14on the inner surface13bfacing the substrate11and outside the light-emitting region132. Since the shading coating layer14will not cover the light-emitting region132of the housing13, the light-emitting path of the light-emitting device15will not be shaded. Preferably, the transmittance of the shading material for the wavelengths of the light emitting by the light-emitting device15is preferably less than 20%.

Specifically, the light-sensing device12and the light-emitting device15are spaced on the substrate11along a horizontal direction Y. The housing13covers the light-sensing device12and the light-emitting device15from above the substrate11along the vertical direction X. The vertical direction X is perpendicular to the horizontal direction Y. According to the present embodiment, the housing13includes a rib part133protruding toward the substrate11along the vertical direction X. The rib part133is located between the light-sensing device12and the light-emitting device15along the horizontal direction Y. The compartment formed between the substrate11and the inner surface13bof the housing13is divided into a first compartment R1and a second compartment R2by the rib part133. The light-sensing device12is located in the first compartment R1; the light-emitting device15is located in the second compartment R2. The housing13is made of a transparent material. It is not necessary to drill a hole for light passage. In other words, the first compartment R1and the second compartment R2are hermetic. Consequently, although no transparent plastic material is used to seal the light-sensing device12according to the present embodiment, the light-sensing device12, the light-emitting device15, and other structures on the substrate11can still be protected by the housing13by blocking external moist, dust, or dirt from contacting. It is noteworthy that according to some embodiments of the present application, if the housing13does not include the rib part13, the light-sensing device12, the light-emitting device15, and other structures on the substrate11share the same compartment with the protection by the housing13.

It is noteworthy that, as shown inFIG.4B, according to the present embodiment, a surface133aof the rib part133facing the first compartment R1includes the shading coating layer14. Alternatively, the surface133bof the rib part133facing the second compartment R2includes the shading coating layer14. Thereby, the shading coating layer14on the rib part133can block the light emitted from the light-emitting device15to prevent crosstalk signals formed by the light emitted from the light-emitting device15to the light-sensing unit121of the light-sensing device12directly or indirectly.

More importantly, the housing13according to the present embodiment can include an optical structure, which generally can be a lens structure, a filter structure (such as a polarizer or a color filter), a diffusing structure, or an optical microstructure. InFIGS.3,4A, and4B, it is shown that the housing13can include a light-sensing lens134and a light-emitting lend135. The light-sensing lens134is disposed in the light-receiving region131of the housing13; the light-emitting lens135is disposed in the light-emitting region132of the housing13. Since the housing13according to the present of the present application is made of a transparent material, the light-sensing lens134and the light-emitting lens135can be fabricated integrally with the housing13. Namely, these lens structures can be formed while molding and manufacturing the housing13. In practice, the light-sensing lens134and the light-emitting lens135can be formed by another molding process. Anyhow, compared to manufacturing lenses using the transparent plastic material94according to the prior art and facing limited lens design flexibility and fabrication difficulty, the housing13according to the present embodiment of the present application is fixed to the substrate11after the housing13is completed. Consequently, the design freedom and fabrication difficulty for the light-sensing lens134and the light-emitting lens135are apparently superior to the prior art.

Please refer toFIG.6andFIG.7.FIG.6shows a cross-sectional view of the optical sensor module according to the second embodiment of the present application;FIG.7shows a perspective view of the optical sensor module according to the second embodiment of the present application. The present embodiment is used to illustrate that, in addition to the inner surface13bof the housing13facing the substrate11, the optical structures including the light-sensing lens134and the light-emitting lens135as described above can alternatively be disposed on the outer surface13cof the housing13opposite to the substrate11. For example, another light-sensing lens136is disposed on the outer surface13cof the substrate11. Besides, according to the second embodiment, it is shown that no matter the light-receiving region131or the light-emitting region132, the housing13can include a plurality of optical structures, which is quite different from the prior art. This is because, according to the prior art, to manufacture the lens942using the transparent plastic material94with the transparent plastic material94enveloping the light-sensing device92and the light-emitting device93, only the surface opposite to the substrate91can be used to dispose the optical structures. In contrast, according to the embodiments of the present application, the compartment formed between the substrate11and the inner surface13bof the housing13is used to accommodate and protect the light-sensing device12and the light-emitting device15. Thereby, the design freedom for the optical structures is improved substantially.

Although convex lenses are adopted to illustrate the optical structures of the housing13according to the embodiments described above, the optical structures can be different structures depending on practical applications. For example, as shown inFIG.8A, the light-sensing lens134can be a concave lens. Alternatively, the light-emitting lens135can even be replaced by an optical microstructure135′. Furthermore, as shown inFIG.8B, since the housing13according to the embodiments of the present application is made of a transparent material, even the optical structures are not fabricated on the housing13directly, they can be assembled to the housing13. For example, the housing13can include a hole in the light-receiving region131. This hole can then be used for assembling the optical structures such as a lens structure137or a filtering structure138. Nonetheless, one or more of the lens structure137and the filtering structure138should preferably seal the hole for maintaining hermeticity of the compartment between the housing13and the substrate11. Alternatively, a blind via can be formed in the housing13before or after disposing the light-emitting lens135in the light-emitting region132. The blind via, likewise, can be used to assemble the optical structures such as a diffusing structure139. In contrast, the openings on the opaque lid95for receiving and emitting light according to the prior art are not suitable for combining with the optical structures, because the opaque property of the lid95might affect the characteristics of the optical structures. As described above, to solve this problem, the optical structures should be manufactured as independent modules (for example, use a transparent material to manufacture additional tube lenses as the optical structures) according to the prior art before bonding to the opaque lid95. In contrast, these additional components and processes are omitted in the embodiments according to the present application.

Please refer toFIG.9andFIG.10.FIG.9shows a cross-sectional view of the optical sensor module according to the third embodiment of the present application;FIG.10shows a cutaway view of the optical sensor module after assembly according to the third embodiment of the present application. The difference between the present embodiment and the previous ones is that, in the shading coating layer14according to the present embodiment, the material of a first shading coating layer14afacing the light-emitting device15is used to shade the light emitted from the light-emitting device15. Thereby, the material with smaller transmittance for the wavelength of the light emitted by the light-emitting device15can be selected. Contrarily, since the external noise light with various wavelengths can be reflected by the housing13to the light-sensing device12, the material of a second shading coating layer14bfacing the light-sensing device12can be selected to have smaller transmittance for wide wavelengths. In addition, although the shading coating layer14are all disposed on the inner surface13bof the housing13according to the previous embodiments, a third shading patterned layer14ccan be formed in a region on the outer surface13cof the housing13opposite to the substrate11according to the present embodiment for reinforcing the shading effect in this region.

In addition, according to the present embodiment, the light-sensing device12can still be sealed in a transparent plastic material16. More specifically, the transparent plastic material16is a transparent packaging material. A liquid transparent glue material (for example, resin) is first injected into the mold contacting the substrate11. After solidification, the mold is removed. Then the light-sensing device12is enveloped in the transparent plastic material16individually and thus partially reinforcing the protection for the light-sensing device12. Nonetheless, in practice, while executing the packaging method for the optical sensor module according to the present application, the finished housing13is still connected and fixed to the substrate11after forming the transparent plastic material16. This is still no cutting process on the transparent plastic material16. Moreover, according to the present embodiment, since the transparent plastic material16is disposed additionally, the transparent plastic material16can also include an optical structure161, which can also include a lens structure, a filter structure, a diffusing structure, or an optical microstructure for facilitating the housing13to achieve the desired optical effects.

To sum up, the optical sensor module and the packaging method thereof according to the present application use a transparent material to manufacture the housing. Then the shading coating layer is disposed on the housing. Thereby, no hole is required on the housing for light passage. While protecting the optical elements including the light-sensing device and the light-emitting device, the performance of the optical sensor module can still be maintained by avoiding interference from noise light. According to the optical sensor module and the packaging method thereof according to the present application, no complicated cutting process on the transparent plastic material is required. Thereby, the production yield can be increased; the effective area for disposing circuit structures is further extended; and the packaging design can be miniaturized. In addition, the optical sensor module further improves the design freedom for optical structures significantly while reducing the manufacturing difficulty. Meanwhile, compared to the prior art, no extra component, module, and process is required to assemble the optical structures.

Accordingly, the present application conforms to the legal requirements owing to its novelty, nonobviousness, and utility. However, the foregoing description is only embodiments of the present application, not used to limit the scope and range of the present application. Those equivalent changes or modifications made according to the shape, structure, feature, or spirit described in the claims of the present application are included in the appended claims of the present application.