Optical ranging module

Abstract

An optical ranging module is defined with an object side and an element side opposite to the object side, and comprises: an optical emission unit; an optical receiving unit; the supporting cover comprises a top and an annular side wall connected with the top, the top is provided with an object side surface, the annular side wall is provided with an outer surface, the top comprises two openings penetrating from the object side to the element side, and the optical transmitting unit and the optical receiving unit are arranged in the two openings respectively; the base is arranged on one side, facing the element side, of the supporting cover; the conductive film is arranged on the object side surface of the top of the supporting cover and the outer surface of the annular side wall; and an anti-reflective film covering the conductive film on the top of the support cover. The anti-reflection film can be made of a low-chromaticity and low-brightness material, so that the reflectivity of the top of the supporting cover is reduced, the measurement accuracy of the optical distance measuring module can be improved, and a terminal product (electronic device) is enabled to present a relatively consistent appearance.

Description

Technical Field

[0001] This invention relates to an optical ranging module, and more particularly to an optical ranging module including an anti-reflective coating. Background Technology

[0002] Time-of-Flight (ToF) ranging is a technology that uses a transmitter to continuously send light waves to a target object, and then uses a sensor to receive the light waves returning from the target object. The distance to the target object is determined by detecting the time it takes for the light waves to travel (round trip). Currently, three-dimensional cameras in electronic devices mainly use optical ranging modules with ToF capabilities, which include an optical transmitting unit, an optical receiving unit, and a support cover.

[0003] Generally, consumer electronics products with communication functions, such as smartphones, televisions, and digital cameras with Wi-Fi or Bluetooth, not only have electromagnetic interference shielding on their casings to meet various certification standards, but also shield electronic components to reduce malfunctions caused by electromagnetic interference between different chips or electronic components. For optical ranging modules with Time-of-Flight (ToF) capabilities, the current practice is to form a thin metal film (such as an electromagnetic interference coating, EMIcoating) on ​​the outer surface of the support cover to reduce electromagnetic interference generated by the electronic components.

[0004] However, metal thin films typically have high light reflectivity, which can easily generate stray light in electronic devices, causing measurement interference to optical ranging modules. Summary of the Invention

[0005] To address the aforementioned problems, an objective of this invention is to provide an optical ranging module with an anti-reflective film covering a conductive film on top of a support cover. Furthermore, the anti-reflective film is a low-chromaticity and low-brightness material, reducing the reflectivity of the top of the support cover, thereby improving the measurement accuracy of the optical ranging module. Based on the above objective, this invention provides an optical ranging module defining an object side and an element side opposite to the object side, and comprising: an optical emitting unit, including a first optical lens group and a light source sequentially from the object side to the element side; an optical receiving unit, including a second optical lens group and an optical sensor sequentially from the object side to the element side; and a support cover including a top and an annular sidewall connecting the top, wherein the top has an object-side surface, the annular sidewall has an outer surface, and the top includes two openings extending from the object side to the element side. The first optical lens group of the optical emitting unit... The lens assembly and the second optical lens assembly of the optical receiving unit are respectively disposed in the two openings; a base is disposed on the side of the support cover facing the element, and a first and a second accommodating space are defined between the base and the support cover, the first accommodating space is used to accommodate the first optical lens assembly and the light source of the optical emitting unit, and the second accommodating space is used to accommodate the second optical lens assembly and the optical sensor of the optical receiving unit; a conductive film is disposed on the object-side surface of the top of the support cover and the outer surface of the annular sidewall; and an anti-reflective film covers the conductive film located on the top of the support cover.

[0006] Optionally, the optical ranging module further includes a conductive adhesive disposed at the connection between the conductive film and the base and electrically connected to the conductive film.

[0007] Optionally, the conductive layer has a thickness between 1000 μm and 20000 μm.

[0008] Optionally, the material of the conductive layer is selected from one of gold, silver, copper, nickel, chromium or stainless steel.

[0009] Optionally, the antireflective film is a low-chromaticity material selected from either titanium trioxide or silicon dioxide.

[0010] Optionally, the antireflective film has a thickness between 20 μm and 2000 μm.

[0011] Optionally, the object-side surface of the antireflective film has a luminance of less than 5 cd / m. 2 .

[0012] Optionally, the conductive film on the annular sidewall has a luminance between 15 cd / m. 2 Up to 30 cd / m 2 between.

[0013] Optionally, the antireflective film has an optical reflectivity of less than 5% in the optical wavelength range of 380 nm to 980 nm.

[0014] Optionally, the anti-reflective film further extends to cover the conductive film on the annular sidewall, exposing only one area so that the conductive film contacts the conductive adhesive.

[0015] According to the optical ranging module of the present invention, the anti-reflective film can reduce the light reflectivity of the conductive film on the top of the support cover, thereby reducing the generation of stray light and improving the measurement accuracy of the optical ranging module. Furthermore, the anti-reflective film has lower luminance and chromaticity, and its blackening effect makes the end product (electronic device) present a more consistent appearance. Attached Figure Description

[0016] Figure 1 This is a cross-sectional schematic diagram of the optical ranging module according to the first embodiment of the present invention, showing that a conductive film is disposed on the top of the support cover and the annular sidewall, and an anti-reflective film covers the conductive film located on the top of the support cover.

[0017] Figure 1A This is a perspective view of the support cover, optical transmitting unit, and optical receiving unit according to the first embodiment of the present invention.

[0018] Figure 2 This is a cross-sectional schematic diagram of the optical ranging module according to the second embodiment of the present invention, which shows that the anti-reflective film further extends to cover the conductive film located on the annular sidewall, and only exposes a region so that the conductive film is in contact with the conductive adhesive.

[0019] Figure 2A This is a perspective view of the support cover, optical transmitting unit, and optical receiving unit according to the second embodiment of the present invention.

[0020] Figure 3 The reflectance spectra of various materials on the top of the support cover of the present invention at different wavelengths show the material properties of the support cover, the conductive film and the anti-reflective film.

[0021] In the picture:

[0022] 1, 2: Optical ranging module; 110, 210: Optical transmitting unit; 112, 212: First optical lens group;

[0023] 113, 213: Light source; 120, 220: Optical receiving unit; 122, 222: Second optical lens group;

[0024] 123, 223: Optical sensors; 130, 230: Support covers; 140, 240: Bases; 150, 250: Conductive films;

[0025] 160, 260: Anti-reflective film; 170, 270: Driving element; 180, 280: Control element;

[0026] a11, a21: First central axis; a12, a22: Second central axis; b11, b21: First opening;

[0027] b12, b22: Second opening; F: Exposed area; G1, G2: Conductive adhesive; L1, L2: Light wave;

[0028] S11, S21: Object-side surfaces; S12, S22: Outer surfaces; SP11, SP21: First accommodating space;

[0029] SP12, SP22: Second accommodating space; T: Target object; T11, T21: Top; T12, T22: Annular sidewall;

[0030] O: Object side; E: Component side. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0032] Figure 1 This is a cross-sectional schematic diagram of the optical ranging module according to the first embodiment of the present invention, showing that a conductive film is disposed on the top of the support cover and the annular sidewall, and an anti-reflective film covers the conductive film located on the top of the support cover. Figure 1A This is a perspective view of the support cover, optical transmitting unit, and optical receiving unit according to the first embodiment of the present invention. Please refer to... Figure 1 , Figure 1A The optical ranging module 1 defines an object side O and an element side E opposite to the object side, and includes: an optical transmitting unit 110, an optical receiving unit 120, a support cover 130, a base 140, a conductive film 150 and an anti-reflective film 160.

[0033] The optical emitting unit 110 has a first central axis a11 and a first lens barrel surrounding the first central axis a11. A first optical lens group 112 and a light source 113 are sequentially arranged from the object side O to the element side E of the first lens barrel. The first optical lens group 112 includes at least one optical lens. The light source 113 is an infrared light source that provides an infrared light wave toward the target object T located on the object side O. It can be a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser (EEL), but is not limited to these.

[0034] The optical receiving unit 120 has a second central axis a12 and a second lens barrel surrounding the second central axis a12. A second optical lens group 122 and an optical sensor 123 are sequentially arranged from the object side O to the element side E of the second lens barrel. The second optical lens group 122 includes at least one optical lens. The optical sensor 123 is generally a photosensitive element used to receive light waves passing through the second optical lens group 122. It can be a complementary metal oxide semiconductor (CMOS) or a charge coupled device (CCD), but is not limited to these.

[0035] The support cap 130 may be a housing, including a top T11 and an annular sidewall T12 connecting the top T11. The top T11 has an object-side surface S11 that is a plane. The annular sidewall T12 extends from the top T11 toward the element side E and has an outer surface S12. The top T11 includes a first opening b11 and a second opening b12 that pass through the object side O and are disposed on the element side E. The first optical lens group 112 of the optical emitting unit 110 is disposed in the first opening b11, and the object side of the first optical lens group 112 of the optical emitting unit 110 and the object side of the first opening b11 both face the object side O. The light wave L1 of the light source 113 passes through the first optical lens group 112 and then through the first opening b11 to the object side O. The second optical lens group 122 of the optical receiving unit 120 is disposed in the second opening b12. The object side of the second optical lens group 122 and the object side of the second opening b12 both face the object side O. The optical sensor 123 receives light wave L2 from the object side O and passing through the second optical lens group 122. The support cover 130 is typically made of black plastic material and manufactured by injection molding, but is not limited to this.

[0036] The base 140 is disposed on the side of the support cover 130 facing the element side E, and a first accommodating space SP11 and a second accommodating space SP12 are defined between the base 140 and the support cover 130. The first accommodating space SP11 is used to accommodate the first optical lens group 112 and the light source 113 of the optical emitting unit 110, and the second accommodating space SP12 is used to accommodate the second optical lens group 122 and the optical sensor 123 of the optical receiving unit 120.

[0037] The conductive film 150 is disposed on all or part of the object-side surface S11 of the top T11 of the support cover 130, and the conductive film 150 is disposed on all or part of the outer surface S12 of the annular sidewall T12.

[0038] The anti-reflective film 160 covers the conductive film 150 on the top T11 of the support cover 130. The anti-reflective film 160 has a thickness between 20 μm and 2000 μm. The object-side surface S11 of the anti-reflective film 160 has a luminance of less than 5 cd / m. 2 .

[0039] The optical ranging module 1 includes an optical emitting unit 110 that further includes a driving element 170 electrically connected to the light source 113, an optical receiving unit 120 that further includes a control element 180 electrically connected to the optical sensor 123, a base 140 that includes a wire (not shown) electrically connected to the driving element 170 or the control element 180, and an optical ranging module 1 that includes a conductive adhesive G1 disposed at the connection between the conductive film 150 and the base 140 for electrically connecting the conductive film 150 and the wire.

[0040] In detail, in the aforementioned optical ranging module, the conductive film 150 disposed on the support cover 130 is electrically connected to the ground terminal in the wire of the base 140 through the conductive adhesive G1, so that the conductive film 150 acts as an EMI coating to shield the electronic device from external electromagnetic interference. The conductive film 150 can be formed by processes such as electroplating, vapor deposition, vacuum sputtering, or optical sputtering; when the conductive film 150 has a relatively large thickness range between 1000μm and 20000μm, it can have a low electrical resistance; preferably, the conductive layer 150 can be a material with low electrical resistance, such as a metallic material of gold, silver, copper, nickel, chromium, or stainless steel.

[0041] Figure 2 This is a cross-sectional schematic diagram of the optical ranging module according to the second embodiment of the present invention. Figure 2A This is a perspective view of the support cover, optical transmitting unit, and optical receiving unit according to a second embodiment of the present invention. Please refer to... Figure 2 , Figure 2A The optical ranging module of the second embodiment is generally similar to that of the optical ranging module of the first embodiment, with similar components labeled with similar reference numerals. The difference between the second and first embodiment optical ranging modules 2 and 1 is that in the second embodiment, the anti-reflective film 260 of the optical ranging module 2 of the present invention covers the conductive film 250 on the top T21 of the support cover 230 and further extends to cover the conductive film 250 on the annular sidewall T22, and only exposes a region F so that the conductive film 250 contacts the conductive adhesive G2.

[0042] Please refer to Figure 1 and Figure 2In the aforementioned optical ranging module, the conductive film is disposed on the top of the support cover and the annular sidewall of the support cover. The anti-reflective film may only cover the conductive film on the top of the support cover (as in the first embodiment), or it may extend to cover the conductive film on the annular sidewall (as in the second embodiment). The anti-reflective films 160 and 260 may be titanium trioxide or silicon dioxide, serving as a low-chromaticity material and an antioxidant material, respectively. Please refer to... Figure 1 When the antireflective film 160 only covers the conductive film 150 on the top T11 of the support cover 130, the antireflective film 160 has a luminance (L*) of less than 5 cd / m. 2 Furthermore, it possesses an optical reflectivity of less than 5% between optical wavelengths of 380nm and 980nm, thus reducing stray light formation and improving the ranging accuracy of the optical ranging module 1; please refer to... Figure 2 When the antireflective film 260 further extends to cover the conductive film 250 on the annular sidewall T22, and only exposes a region F so that the conductive film 250 contacts the conductive adhesive G2, the antireflective film 260 can act as an anti-oxidation film to reduce the oxidation of the conductive film 250. Furthermore, the exposed region F of the antireflective film 260 has a luminance (L*) between 15 cd / m. 2 Up to 30 cd / m 2 Between these areas, the unexposed region of the antireflective film 260 has a luminance (L*) of less than 5 cd / m. 2 .

[0043] Figure 3 The images show the reflectance spectra of various materials on the top of the support cover of the present invention at different light wavelengths, illustrating the material properties of the support cover, conductive film, and anti-reflective film. In the aforementioned optical ranging module, when only the conductive film is disposed on the support cover, the reflectance in the light wavelength range of 380nm to 980nm is between 28% and 37%, which easily leads to stray light. However, when the conductive film and the anti-reflective film of the present invention are disposed on the support cover, the reflectance in the light wavelength range of 380nm to 980nm is less than 5%, which can meet the better ranging accuracy of the optical ranging module.

[0044] The optical ranging module 1 provided by this invention can be applied to optical systems according to specific needs. It can be used in various ways, including face recognition for 3D (three-dimensional) image acquisition, autofocus or depth sensing shooting functions for consumer electronics, tracking user movements in virtual reality (VR) and augmented reality (AR), driver assistance systems (ADAS) or gesture control in autonomous driving and the automotive industry, positioning and navigation object recognition in robotics and industrial automation, and real-time distance measurement in drones.

[0045] The embodiments described above are merely preferred embodiments for fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. An optical ranging module, defining an object side and an element side opposite to the object side, characterized in that, include: An optical emitting unit, from the object side to the element side, includes a first optical lens group and a light source in sequence; An optical receiving unit includes, from the object side to the element side, a second optical lens group and an optical sensor in sequence. A support cover includes a top and an annular sidewall connected to the top, wherein the top has an object-side surface and the annular sidewall has an outer surface, and the top includes two openings extending from the object side to the element side, wherein the first optical lens group of the optical emitting unit and the second optical lens group of the optical receiving unit are respectively disposed in the two openings. A base is disposed on the side of the support cover facing the component, and a first accommodating space and a second accommodating space are defined between the base and the support cover. The first accommodating space is used to accommodate the first optical lens group and the light source of the optical emitting unit, and the second accommodating space is used to accommodate the second optical lens group and the optical sensor of the optical receiving unit. A conductive film is disposed on the object-side surface of the top of the support cover and on the outer surface of the object-side surface and the annular sidewall; as well as An anti-reflective film covers the conductive film on the top of the support cover.

2. The optical ranging module as described in claim 1, characterized in that, The optical ranging module further includes a conductive adhesive disposed at the connection between the conductive film and the base and electrically connected to the conductive film.

3. The optical ranging module as described in claim 1, characterized in that, The conductive layer has a thickness between 1000 μm and 20000 μm.

4. The optical ranging module as described in claim 1, characterized in that, The material of the conductive layer is selected from one of gold, silver, copper, nickel, chromium or stainless steel.

5. The optical ranging module as described in claim 1, characterized in that, The antireflective film is a low-chromaticity material selected from either titanium trioxide or silicon dioxide.

6. The optical ranging module as described in claim 1, characterized in that, The antireflective film has a thickness between 20 μm and 2000 μm.

7. The optical ranging module as described in claim 1, characterized in that, The object-side surface of the antireflective film has a luminance of less than 5 cd / m. 2 .

8. The optical ranging module as described in claim 1, characterized in that, The conductive film on the annular sidewall has a brightness of 15 cd / m. 2 Up to 30 cd / m 2 between.

9. The optical ranging module as described in claim 1, characterized in that, The antireflective film has an optical reflectivity of less than 5% between optical wavelengths of 380 nm and 980 nm.

10. The optical ranging module as described in claim 2, characterized in that, The anti-reflective film further extends to cover the conductive film on the annular sidewall, exposing only one area so that the conductive film comes into contact with the conductive adhesive.

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