US-12620777-B2 - Optical member, laser module including said optical member, and laser device

Abstract

The present disclosure provides an optical member for use in a laser module that includes a surface emitting laser, the optical member being capable of detecting damage (cracking, peeling, and the like), a method for manufacturing the optical member, a laser module including the optical member, and a laser device.

Inventors

• Takahiro Iwahama
• Takeshi Fujikawa
• Sadayuki FUKUI

Assignees

• DAICEL CORPORATION

Dates

Publication Date

20260505

Application Date

20231127

Priority Date

20181113

Claims (20)

1. 1 . An optical member comprising: a wire containing an electrically conductive substance and being disposed on one surface of the optical member in open-ended arrangement, wherein an area in which an optical element is formed on the same surface as the surface on which the wire is disposed, wherein the wire is disposed in the area in which the optical element is formed, wherein the optical element includes a plurality of sides, and wherein two ends of the wire face each other and are disposed adjacent to the same side of the plurality of sides of the optical member, or the two ends of the wire are disposed adjacent to a first side and a second side of the plurality of sides of the optical member, the first side is different from the second side, and the two ends of the wire face the same side of the plurality of the optical member.
2. 2 . The optical member according to claim 1 , wherein the electrically conductive substance comprises a metal.
3. 3 . The optical member according to claim 1 , wherein the electrically conductive substance comprises silver or gold.
4. 4 . The optical member according to claim 1 , wherein the optical member comprises at least one type of optical element selected from the group consisting of a diffractive optical element and a microlens array.
5. 5 . The optical member according to claim 1 , wherein the optical member is plastic or a laminate of plastic and inorganic glass.
6. 6 . The optical member according to claim 5 , wherein the plastic is a cured product of a curable epoxy resin composition.
7. 7 . The optical member according to claim 1 , wherein the optical member includes an inorganic glass.
8. 8 . A method for manufacturing the optical member described in claim 1 , the method comprising: applying an ink containing an electrically conductive substance to an optical member by a printing process to form the wire.
9. 9 . The method for manufacturing the optical member according to claim 8 , wherein the printing process includes inkjet printing or screen printing.
10. 10 . The method for manufacturing the optical member according to claim 8 , wherein the optical member is an optical element array in which two or more optical elements are arranged two-dimensionally.
11. 11 . A laser module comprising: an optical member including: a wire containing an electrically conductive substance and being disposed on one surface of the optical member in open-ended arrangement, wherein an area in which an optical element is formed on the same surface as the surface on which the wire is disposed, wherein the wire is disposed in the area in which the optical element is formed, wherein the optical element includes a plurality of sides, and wherein two ends of the wire face each other and are disposed adjacent to the same side of the plurality of sides of the optical member, or the two ends of the wire are disposed adjacent to a first side and a second side of the plurality of sides of the optical member, the first side is different from the second side, and the two ends of the wire face the same side of the plurality of the optical member.
12. 12 . The laser module according to claim 11 , comprising: a surface emitting laser light source is configured to emit a laser light toward a second surface of the optical member opposite to a first surface of the optical member.
13. 13 . A laser device comprising the laser module described in claim 11 .
14. 14 . The laser module according to claim 11 , wherein the electrically conductive substance comprises a metal.
15. 15 . The laser module according to claim 11 , wherein the electrically conductive substance comprises silver or gold.
16. 16 . The laser module according to claim 11 , wherein the optical member comprises at least one type of optical element selected from the group consisting of a diffractive optical element and a microlens array.
17. 17 . The laser module according to claim 11 , wherein the optical member is plastic or a laminate of plastic and inorganic glass.
18. 18 . The laser module according to claim 11 , wherein the optical member includes an inorganic glass.
19. 19 . The optical member according to claim 1 , wherein the wire has, at both ends thereof, a conduction detection mechanism connection portion that connects to a conduction detection mechanism.
20. 20 . The laser module according to claim 11 , wherein the wire has, at both ends thereof, a conduction detection mechanism connection portion that connects to a conduction detection mechanism.

Description

TECHNICAL FIELD The present invention relates to an optical member for use in a laser module including a surface emitting laser light source, a method for manufacturing the same, a laser module including the optical member, and a laser device. The present application claims the rights of priority to JP 2018-213241 filed in Japan on Nov. 13, 2018, and JP 2019-150039 filed in Japan on Aug. 19, 2019, the content of which is incorporated herein. BACKGROUND ART The demand for 3D sensing for recognizing the three-dimensional shape of an object, such as face authentication for avoidance of security risks associated with the popularization of smartphones, a recognition camera for 3D mapping, a gesture recognition controller for a gaming device, automatic driving of an automobile, and machine vision in a plant, has rapidly increased in recent years. Such 3D sensing employs a Time of Flight (TOF) method, a structured light method, and the like. In these methods, laser light is emitted to an object from a laser light source such as a Vertical Cavity Surface Emitting Laser (VCSEL) to obtain information from reflected light. In such 3D sensing, depending on the application and purpose thereof, laser light is controlled and shaped using an optical member including an optical element such as a diffuser, a diffractive optical element, a lens, a prism, a polarizing plate, or the like. For example, in the TOF method, a diffuser is used as an optical element for attaining uniform laser light, and in the structured light method, laser light is controlled and shaped into structured light of a dot pattern or the like using a diffractive optical element (for example, Patent Documents 1 to 3). CITATION LIST Patent Document Patent Document 1: JP 2017-26662 APatent Document 2: JP 2018-511034 TPatent Document 3: JP 2006-500621 T SUMMARY OF INVENTION Technical Problem In 3D sensing, near infrared radiation at 850 nm and 940 nm, which has relatively high safety, is often used as the laser light. However, high power light, such as laser light, may be emitted directly to the eyes in the case of face authentication of a smartphone, which can lead to harm, such as blindness. An optical member including a diffuser, a diffractive optical element, or the like diffuses the laser light, and thus also serves to reduce such harm. However, in cases where damage such as cracking or peeling occurs in the optical member due to a drop, impact, or the like, the laser light that has not been diffused is directly emitted to the eyes. Also, if the optical member is degraded or damaged in a 3D sensing system used outdoors and thus in a harsh environment such as sunlight, vibration, or the like, for example, in the case of automatic driving of an automobile, accidents may occur due to erroneous actuation, and such defects need to be detected quickly. However, in known 3D sensing systems, the means for detecting damage to the optical member is not known, and it is a current situation that the optical member continues to be used without such damage being found. Therefore, an object of the present invention is to provide an optical member for use in a laser module including a surface emitting laser, the optical member being capable of detecting damage (cracking, peeling, and the like), and a method for manufacturing the optical member. Another object of the present invention is to provide a laser module including the optical member. Yet another object of the present invention is to provide a laser device including the laser module. Note that the laser module typically undergoes a reflow process for bonding an electrode to a wiring board by soldering. In recent years, high melting point lead-free solder has been used as the solder as a bonding material, and heating treatment in the reflow process has become higher in temperature (for example, a peak temperature of from 240 to 260° C.). In such a situation, a problem has occurred in known laser modules, such as the occurrence of cracking in optical members including an optical element such as a microlens array, a diffractive optical element, or the like, due to heat treatment in the reflow process. Therefore, the optical member used in the laser module is required to have excellent heat resistance, in particular, a property of being not prone to cracking or peeling even when heat treated in the reflow process. Solution to Problem As a result of diligent research to solve the problems described above, the present inventors have discovered that damage to an optical member can be detected by applying a wire containing an electrically conductive substance on an optical member used in a laser module, and monitoring a conducting state of the wire. It has also been discovered that the wire can be easily and efficiently formed by applying an ink containing an electrically conductive substance to the optical member using a printing process. The present invention was completed based on these findings. Specifically, the pr