Projection module, imaging module, and electronic device

A projection module includes a light source, a reflective structure, and an optical structure. The light source emits laser light. The reflective structure includes a first reflective element and a second reflective element. The optical structure includes a first optical element and a second optical element. The reflective structure is disposed between the laser source and the optical structure. The first reflective element reflects a portion of the laser light towards the second reflective element, and transmits a remaining portion of the laser light towards the second optical element. The second reflective element reflects the laser light from the first reflective element towards the first optical element. The first optical element and the second optical element cooperatively project the laser beam towards an object.

FIELD

The subject matter herein generally relates to imaging technologies, and more particularly, to a projection module, an imaging module having the projection module, and an electronic device having the imaging module.

BACKGROUND

3D sensing modules of electronic devices usually have projection modules and receiving modules. The projection module can project light onto an object. The receiving module can receive the light reflected by the object. Then, depth information of the object can be obtained based on the reflected light.

The projection module may be stacked on a specific component of the electronic device, such as a display component or a housing. However, such stacking manner increase a thickness of the electronic device.

DETAILED DESCRIPTION

FIG. 1illustrates an embodiment of a projection module100. The projection module100includes a light source10, a reflective structure20, and an optical structure30. The reflective structure20is disposed between the light source10and the optical structure30.

The light source10can emit laser light. In an embodiment, the light source10can emit infrared laser light. The light source10may be a vertical cavity surface emitting laser (VCSEL). Since only a VCSEL is included, the projection module100can have a small size while ensuring a power of the laser light.

The reflective structure20includes a first reflective element21and a second reflective element22. The optical structure30includes a first optical element31and a second optical element32. The first reflective element21is disposed on a transmission path of the laser light from the light source10. The first reflective element21can reflect a portion of the laser light towards the second reflective element22, and transmits a remaining portion of the laser light towards the second optical element32. The second reflective element22faces the first reflective element21, and is disposed on a transmission path of the laser light reflected by the first reflective element2. The second reflective element22can reflect the laser light from the first reflective element21towards the first optical element31. The first optical element31can project the laser light from the second reflective element22towards the object to scan the object (for example, a human face). The second optical element32can project the laser light from the first reflective element21towards the object as supplement light, to assist the first optical element31to scan the object.

Thus, the first optical element31has an object scanning function, and the second optical element32has a light supplement function. By disposing the first optical element31and the second optical element32on the transmission paths of the laser light from the light source10, the size of the projection module100can further be reduced.

In at least one embodiment, the first reflective element21and the second reflective element22are parallel to each other. The first reflective element21is a semi-transmissive reflective mirror. The second reflective element22is a total reflective mirror.

Referring toFIG. 1, in at least one embodiment, the first optical element31and the second optical element32are spaced apart from each other. Referring toFIG. 2, in other embodiments, the first optical element31and the second optical element32are joined together.

In at least one embodiment, the first optical element31may be a diffractive optical element (DOE), and the second optical element32may be a diffuser.

In at least one embodiment, only one first optical element31and only one second optical element32are included. In other embodiments, at least two first optical elements31may be included, which are jointed to each other. At least two second optical elements32may be included, which are connected to each other. By setting at least two first optical elements31and/or at least two second optical elements32, most of the laser light emitted by the light source10can be ensured to be received by the first optical elements31and/or the second optical elements32, thereby improving utilization rate of the laser light.

FIG. 3illustrates an embodiment of an imaging module200. The imaging module200includes a receiving module201and the projection module100. The receiving module201may include a lens2011and an image sensor2012on an image side of the lens2011. The lens2011can receive the laser light reflected by the object, and converge the laser light towards the image sensor2012. The image sensor2012can collect the laser light. The depth information (for example, 3D contour information) of the object can then be determined accordingly.

FIG. 4illustrates an embodiment of an electronic device300. The electronic device300can be a mobile phone, a wearable device, a computer, or a vehicle.

When the imaging module200is applied to the electronic device300, the projection module100can realize the object scanning function and light supplement function without adding other optical components. Thus, the size of the electronic device300can be reduced.