TWI870838B - Sensing module - Google Patents

Abstract

A sensing module including a light-emitting device and a sensing device is provided. The light-emitting device includes a light-emitting element and an optical element. The light-emitting element is used to provide an illumination beam. The optical element is disposed on the transmission path of the illumination beam, and is used for transmitting the illumination beam to a plurality of sub-sensing areas of a sensing area to generate a plurality of reflected light beams. The sensing device includes a sensing element and a lens array. The sensing element is disposed on the transmission path of the reflected light beams, and is used for receiving the reflected light beams to generate a plurality of sub-sensing signals. The lens array is arranged on the sensing element. The lens array includes a plurality of sub-lenses, which are respectively arranged on the transmission paths of the reflected light beams.

Description

Sensor module

The present invention relates to an electronic device, and in particular to a sensing module.

In the current application of stereo depth sensing technology, from long-distance remote sensing terrain detection to medium-distance factory automation unmanned transport vehicles, smart machinery, vehicle-assisted driving or unmanned vehicles, drones, etc., and short-distance applications include sweeping robots, gesture recognition devices and mobile phone face recognition systems, etc., which are extremely wide and ubiquitous. The rapid development in recent years is mainly driven by the application of this technology in consumer goods and automotive electronics.

In the application of general stereo depth sensing technology, a Time of Flight (TOF) device is used. From the basic structure of a general TOF device, it can be seen that its planar spatial resolution is mainly limited by the resolution of the TOF sensor. In the current market, the QVGA (Quarter VGA) specification with a resolution of 320×240 is the main specification. Although TOF devices with a resolution of 640×480 have been developed, such devices still need to be improved in pixel miniaturization due to avalanche photodiodes (APD) or single photon avalanche diodes (SPAD), and the entire device is relatively large in high-resolution situations. At the same time, in the case of a large amount of high-resolution data, it will gradually lose the advantage of extremely high response speed compared with other technologies. Therefore, how to improve the quality of time-of-flight ranging devices is a goal that needs to be worked on in this field.

The present invention provides a sensing module which can further improve the sensing resolution and has a smaller volume.

The present invention provides a sensing module, including a light-emitting device and a sensing device. The light-emitting device includes a light-emitting element and an optical element. The light-emitting element is used to provide an illumination beam. The optical element is arranged on the transmission path of the illumination beam, and is used to transmit the illumination beam to multiple sub-areas of a sensing area to generate multiple reflected beams. The sensing device includes a sensing element and an array lens. The sensing element is arranged on the transmission path of the multiple reflected beams, and is used to receive the multiple reflected beams to generate multiple sub-sensing signals. The array lens is arranged on the sensing element. The array lens includes multiple sub-lenses, which are respectively arranged on the transmission path of the multiple reflected beams.

In one embodiment of the present invention, the optical element includes a wheel, a rotating shaft, a plurality of diffraction elements and a driving element. The rotating shaft is disposed at the rotation center of the wheel. The plurality of diffraction elements are disposed on the wheel and surround the rotating shaft. The driving element is connected to the rotating shaft to drive the rotating shaft to rotate.

In an embodiment of the present invention, the number of the plurality of diffraction elements is equal to the number of the plurality of sub-regions.

In one embodiment of the present invention, the driving element drives the shaft in a time sequence to drive the wheel to rotate.

In an embodiment of the present invention, the optical element includes a light modulation element disposed on a transmission path of the illumination light beam for transmitting the illumination light beam to a plurality of sub-areas in a time sequence.

In one embodiment of the present invention, the above-mentioned multiple sub-areas do not overlap with each other.

In an embodiment of the present invention, the area range outlines of the above-mentioned multiple sub-areas are rectangular.

In an embodiment of the present invention, the above-mentioned sensing area is composed of a plurality of sub-areas.

In an embodiment of the present invention, the number of the plurality of sub-regions is equal to the number of the plurality of sub-lenses.

In an embodiment of the present invention, the sensing module further includes a processing device electrically connected to the sensing element for generating a sensing signal according to a plurality of sub-sensing signals.

Based on the above, in the sensing module of the present invention, the sensing module includes a light-emitting device and a sensing device, wherein the optical element transmits the illumination light beam provided by the light-emitting element to multiple sub-areas of the sensing area to generate multiple reflected light beams. Multiple sub-lenses in the array lens respectively transmit the reflected light beams provided by different sub-areas to the sensing element to generate multiple sub-sensing signals. Then, a sensing signal with a higher resolution can be obtained by signal data processing. In this way, the sensing resolution of the sensing module can be further improved, and the sensing module has a smaller volume.

In order to make the above features and advantages of the present invention more clearly understood, embodiments are specifically cited below and described in detail with reference to the accompanying drawings.

FIG. 1A to FIG. 1D are schematic diagrams of a sensing module of an embodiment of the present invention transmitting an illumination beam at different timings. FIG. 2 is a schematic diagram of a sensing device of the sensing module of FIG. 1A receiving multiple reflected beams. Please refer to FIG. 1A to FIG. 1D first. The present invention provides a sensing module 100, such as a time-of-flight ranging device with structured light illumination, which is used to provide structured light to a sensing target and use time-of-flight ranging (Time of Fight) technology to perform stereo depth sensing, which can be applied to different fields such as terrain detection, smart machinery, vehicle assisted driving, unmanned devices, and mobile phone recognition devices. The sensing target can be any tangible object, and the present invention is not limited thereto.

In this embodiment, the sensing module 100 includes a light emitting device 110 and a sensing device 120. The light emitting device 110 is used to provide an illumination beam L1 to a sensing target, and the sensing device 120 is used to receive a reflected beam L2 reflected by the sensing target for sensing. In detail, the surface of the sensing target sensed by the sensing module 100 can be defined as a sensing area 50, and the sensing area 50 can be composed of a plurality of defined sub-areas 52, 54, 56, and 58. In this embodiment, the plurality of sub-areas 52, 54, 56, and 58 do not overlap with each other. For example, the area range outlines of these sub-areas 52, 54, 56, 58 are, for example, rectangular, and the area range outlines of these sub-areas 52, 54, 56, 58 can be spliced to form the sensing area 50, as shown in FIG. 1A. However, in different embodiments, multiple sub-areas 52, 54, 56, 58 can also be designed to overlap and cover the entire sensing area 50, and the present invention is not limited thereto. The following description will take four sub-areas 52, 54, 56, 58 whose shapes can be spliced to form the sensing area 50 as an example.

In detail, the light-emitting device 110 includes a light-emitting element 112 and an optical element 114. The light-emitting element 112 provides an illumination beam L1. For example, in the present embodiment, the light-emitting element 112 is, for example, a light-emitting diode (LED) or a laser diode (LD), and the illumination beam L1 is, for example, an infrared beam. The optical element 114 is disposed on the transmission path of the illumination beam L1 to transmit the illumination beam L1 to a plurality of sub-areas 52, 54, 56, 58 of the sensing area 50 to generate a plurality of reflected beams L2. Specifically, the optical element 114 includes a wheel 202, a rotating shaft 204, a plurality of diffraction elements 206, and a driving element (not shown). The rotating shaft 204 is disposed at the rotation center of the wheel 202. A plurality of diffraction elements 206 are disposed on the wheel 202 and around the rotating shaft 204. A driving element is connected to the rotating shaft 204, and the driving element is, for example, a motor, for driving the rotating shaft 204 to rotate so as to drive the wheel 202 to rotate. Therefore, the illumination light beam L1 will be transmitted through different diffraction elements 206 at any time. The driving element can be selectively disposed on the wheel 202 or set elsewhere, and the present invention is not limited thereto.

In the present embodiment, the number of the plurality of diffraction elements 206 is the same as the number of the plurality of sub-regions 52, 54, 56, 58, that is, for example, four. The plurality of diffraction elements 206 are, for example, diffractive optical elements (DOE), which are used to form the illumination light beam L1 passing therethrough into structured light and give it specific directivity. For example, as shown in FIG. 1A to FIG. 1D , in the present embodiment, when the illumination light beam L1 is transmitted through different diffraction elements 206 in a time sequence, structured light illuminating different sub-regions 52, 54, 56, 58 is generated. The illumination light beam L1 is transmitted through different diffraction elements 206 in a time sequence, which can be realized by rotating the wheel 202 to replace the diffraction element 206 located on the optical axis. In other words, the present embodiment irradiates the illumination light beam L1 in different directions through different diffraction elements 206 to form structured lights corresponding to the sub-areas 52, 54, 56, 58, and these lights will be reflected back to the sensing module 100 in different directions by each sub-area 52, 54, 56, 58, and become the reflected light beam L2 received by the sensing device 120.

Please refer to FIG. 2. For the convenience of explanation, FIG. 2 only shows a portion of the sensing area 50, with sub-areas 52 and 54 being shown as examples. On the other hand, the sensing device 120 includes a sensing element 122 and an array lens 124. The sensing element 122 is disposed on the transmission path of multiple reflected light beams L2, and is used to receive multiple reflected light beams L2 to generate multiple sub-sensing signals. The sensing element 122 is, for example, an infrared sensor. For example, the present embodiment uses a time-of-flight sensor (ToF sensor) with a resolution of 320 x 240. The array lens 124 is disposed on the sensing element 122. The array lens 124 includes a plurality of sub-lenses M, which are respectively disposed on the transmission path of the multiple reflected light beams L2. In other words, the number of the plurality of sub-regions 52, 54, 56, 58 is the same as the number of the plurality of sub-lenses M. In the present embodiment, the number of the sub-lenses M is four, i.e., a 2 x 2 lens array, and the four sub-lenses M are respectively configured on the transmission paths of four different reflected light beams L2. These sub-lenses M can respectively receive the reflected light beams L2 reflected by different sub-regions 52, 54, 56, 58 and transmit them to a single sensing element 122. In other words, since the sensing element 122 can receive the reflected light beam L2 with a resolution of 320 x 240, as the light emitting device 110 provides the illumination light beam L1 to different sub-areas 52, 54, 56, 58 at any time, the sensing element 122 will receive the reflected light beam L2 reflected by different sub-areas 52, 54, 56, 58 at any time, and these reflected light beams L2 can respectively generate sub-sensing signals with a resolution of 320 x 240, and by performing signal data processing on the sub-sensing signals corresponding to different sub-areas 52, 54, 56, 58, a sensing signal with a resolution of 640 x 480 is obtained. In this way, the sensing resolution of the sensing module 100 can be further improved, and the sensing module 100 has a smaller volume. In some embodiments, the sensing module 100 may include a processing device electrically connected to the sensing element 122 to generate a sensing signal according to a plurality of sub-sensing signals. The processing device may be, for example, a central processing unit (CPU) or other types of processors, but the present invention is not limited thereto.

FIG3 is a schematic diagram of another embodiment of the present invention in which the sensing module performs sensing. Please refer to FIG3. The sensing module 100A of this embodiment is similar to the sensing module 100 shown in FIG1A. The difference between the two is that in this embodiment, the optical element 114A in the light-emitting device 110A includes a light modulation element 208, which is arranged on the transmission path of the illumination light beam L1, and is used to sequentially transmit the illumination light beam L1 to different multiple sub-areas 52, 54, 56, 58. The light modulation element 208 is, for example, a spatial light modulator (SLM). The light modulating element 208 changes its state at any time through electrical control to change the transmission direction of the illumination light beam L1 passing through at any time, and transmits the illumination light beam L1 to different sub-areas 52, 54, 56, 58. In this way, the sensing resolution of the sensing module 100A can be further improved, and the sensing module 100A has a smaller volume.

In the embodiment of FIG. 1A to FIG. 1D or FIG. 3 , the sensing area 50 can be selectively defined into nine sub-areas, and a light emitting device 110 that can provide illumination beams L1 to nine different sub-areas is configured to be matched with an array lens 124 in the form of a 3 x 3 lens array, thereby obtaining higher resolution image depth information. In other words, the present invention does not limit the number of different sub-areas to which the illumination beam L1 is projected.

In summary, in the sensing module of the present invention, the sensing module includes a light-emitting device and a sensing device, wherein the optical element transmits the illumination light beam provided by the light-emitting element to multiple sub-areas of the sensing area to generate multiple reflected light beams. Multiple sub-lenses in the array lens respectively transmit the reflected light beams provided by different sub-areas to the sensing element to generate multiple sub-sensing signals. Then, a sensing signal with a higher resolution can be obtained by signal data processing. In this way, the sensing resolution of the sensing module can be further improved, and the sensing module has a smaller volume.

Although the present invention has been disclosed as above by the embodiments, they are not intended to limit the present invention. Any person with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the scope of the attached patent application.

50: Sensing area 52,54,56,58: Sub-area 100,100A: Sensing module 110,110A: Light-emitting device 112: Light-emitting element 114,114A: Optical element 120: Sensing device 122: Sensing element 124: Array lens 202: Wheel 204: Rotating shaft 206: Diffraction element 208: Light modulation element L1: Illumination beam L2: Reflection beam M: Sub-lens

Figures 1A to 1D are schematic diagrams of a sensing module of an embodiment of the present invention transmitting an illumination beam at different timings. Figure 2 is a schematic diagram of a sensing device of the sensing module of Figure 1A receiving multiple reflected beams. Figure 3 is a schematic diagram of a sensing module of another embodiment of the present invention performing sensing.

50: Sensing area

52,54,56,58: Sub-area

100:Sensor module

110: Light-emitting device

112: Light-emitting element

114: Optical components

120:Sensor device

122: Sensing element

124: Array lens

202: Roulette

204: Rotating axis

206:Diffraction element

L1: lighting beam

M: Sub-lens

Claims (19)

A sensing module comprises: at least one lighting device for providing an illumination beam or sequentially providing a plurality of directional sub-beams to a sensing area, wherein the sensing area comprises a plurality of different sub-areas; and a sensing device for receiving a plurality of reflected beams from the plurality of sub-areas to obtain a plurality of sub-depth signals respectively, and generating a depth signal according to the plurality of sub-depth signals, wherein the plurality of sub-areas meet one of the following conditions: (1) the plurality of sub-areas do not overlap with each other, and the depth signal is obtained by combining the plurality of sub-areas in an absolute position manner; and (2) the plurality of sub-areas partially overlap with each other, and the depth signal is obtained by combining the plurality of sub-areas in an edge comparison manner. A sensing module as described in claim 1, wherein the at least one lighting device includes a light-emitting device for providing the lighting beam or the plurality of sub-beams. The sensing module as described in claim 2, wherein the light-emitting device further includes an optical element, which is arranged on the transmission path of the illumination light beam, so as to allow the illumination light beam to form the multiple sub-beams to pass through and be transmitted to the sensing area. A sensing module as described in claim 3, wherein the optical element includes an optical diffraction element or a light modulation element. A sensing module as described in claim 4, wherein the light modulation element includes a scanning mirror. A sensing module as described in claim 1, wherein the illumination beam or the multiple sub-beams are structured light. A sensing module as described in claim 1, wherein the sensing device includes an imaging optical element. A sensing module as described in claim 7, wherein the imaging optical element is an array lens or a scanning moving lens. A sensing module as described in claim 8, wherein the imaging optical element has a zoom function. A sensing module as described in claim 1, wherein the sensing device includes an array lens. A method for image depth sensing includes: providing an illumination beam or sequentially providing a plurality of directional sub-beams to a sensing area, wherein the sensing area includes a plurality of different sub-areas; receiving a plurality of reflected beams from the plurality of sub-areas by a sensing device to obtain a plurality of sub-depth signals; and generating a depth signal according to the plurality of sub-depth signals, wherein the plurality of sub-areas meet one of the following conditions: (1) the plurality of sub-areas do not overlap with each other, and the method for generating the depth signal according to the plurality of sub-depth signals further includes: obtaining the depth signal by combining the plurality of sub-areas in an absolute position manner; and (2) the plurality of sub-areas partially overlap with each other, and the method for generating the depth signal according to the plurality of sub-depth signals further includes: obtaining the depth signal by combining the plurality of sub-areas in an edge matching manner. In the image depth sensing method as described in claim 11, the method of sequentially providing the plurality of directional sub-beams further comprises: controlling the optical element to form the illumination beam into the plurality of sub-beams. The image depth sensing method as described in claim 12, wherein the optical element includes a diffraction element or a light modulation element. The image depth sensing method as described in claim 13, wherein the light modulation element includes a scanning mirror. The image depth sensing method as described in claim 11, wherein the illumination light beam or the multiple sub-beams are structured light. The image depth sensing method as described in claim 11, wherein the sensing device includes an imaging optical element. The image depth sensing method as described in claim 16, wherein the imaging optical element is an array lens or a scanning moving lens. The image depth sensing method as described in claim 17, wherein the imaging optical element has a zoom function. The image depth sensing method as described in claim 11, wherein the sensing device includes an array lens.

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