Light sensing module, preparation method thereof and TOF ranging device

Abstract

The present application relates to the field of TOF ranging, and discloses a light sensing module, a preparation method thereof and a TOF ranging device. The preparation method comprises the following steps: injecting a glassy injection material I into a cavity of a mold I, and demolding to obtain an optical device I; injecting a glassy injection material II into a cavity of a mold II in which the optical device I is placed, and demolding to obtain an integrated body I of the optical device I and a second optical device II; and in sequence, injecting a glassy injection material N into a cavity of a mold N in which an integrated body N-2 is placed, and demolding to obtain an integrated body N-1 of the optical device I to the optical device N, i.e. the light sensing module. The preparation method integrates the light sensing module by one-piece forming of multiple optical components through multiple injection molding, simplifies the device assembly process, shortens the production time, increases the reliability of the optical device and the light sensing module, effectively solves the problem of difficult gluing of special-shaped optical devices, and improves the production yield of the product.

Description

Technical Field

[0001] The present invention relates to the field of time of flight (TOF) ranging, and in particular to a light sensing module and a preparation method thereof, and a TOF ranging device. Background Art

[0002] A TOF ranging device is used to measure the distance of an object. It usually includes a laser emission chip, a light sensing array module, and a signal processing chip. The light sensing array module is usually integrated with multiple optical devices and a housing.

[0003] In the related art, the integration method of the light sensing array module selects one or more of the following processes in combination: (1) Secondary molding process, for example, using a substrate as a carrier, selecting a transparent resin to form an optical device on the substrate by a single molding process, and then selecting a material with a lower light transmittance to form a shell on the substrate by a secondary molding process; however, the reliability risk of transparent resin molding is high and cannot meet the requirements of multiple reflow soldering. (2) Glue bonding (i.e. gluing) process, for example, multiple optical devices and optical devices and shells are assembled by multiple glue bonding; however, the structure of the light sensing module is complex and requires multiple bonding, the product yield is low, and there is a risk of optical devices falling off. Multiple baking between the materials of different optical devices will cause reliability problems. (3) Mechanical assembly process, for example, the optical device and the shell are assembled by mechanical methods such as mold opening; when the optical device size is small, the bonding between the optical devices after mechanical assembly cannot meet the requirements of accuracy and bonding strength.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a photosensitive module and a preparation method thereof, and a TOF ranging device, aiming to solve the problems of poor reliability of optical devices, low product yield of photosensitive modules, or the inability of optical devices to meet accuracy and strength requirements in the existing photosensitive modules prepared by integrating optical devices.

[0006] The technical solutions of the present invention are as follows:

[0007] In a first aspect, the present invention provides a method for preparing a photosensitive module, wherein the photosensitive module includes N optical devices, where N is an integer greater than or equal to 2, and the preparation method includes the following steps: S1, providing a mold I and an injection molding material I, heating the injection molding material I into a glassy state, and injecting the glassy injection molding material I into the cavity of the mold I, cooling and molding, and demolding to obtain the optical device I; S2, providing a mold II and an injection molding material II, heating the injection molding material II into a glassy state, and placing the optical device I at a preset position I in the cavity of the mold II, And inject the glassy injection molding material II into the cavity of the mold II, cool and shape it, and then demold it to obtain an integrated body I of the optical device I and the second optical device II; S3, and so on, provide a mold N and an injection molding material N, heat the injection molding material N into a glassy state, place the integrated body N-2 at a preset position N-1 in the cavity of the mold N, and inject the glassy injection molding material N into the cavity of the mold N, cool and shape it, and then demold it to obtain an integrated body N-1 of the optical device I to the optical device N, and the integrated body N-1 is the photosensitive module.

[0008] In a second aspect, the present invention provides a photosensitive module, which is prepared using any preparation method described in the first aspect.

[0009] In a third aspect, the present invention provides a TOF ranging device, comprising: a substrate; a laser emitting chip, attached to the substrate, for emitting a light signal; the light sensing module described in the second aspect, disposed on the substrate, for calibrating the light signal and transmitting the calibrated light signal to the object to be measured; and a signal processing chip, attached to the substrate, for receiving the light signal reflected by the object to be measured, and calculating the distance of the object to be measured based on the light signal reflected by the object to be measured.

[0010] Compared with the related art, the present invention uses multiple injection molding to form an integrated light sensing module with multiple optical components, which can at least bring the following beneficial effects: (1) It simplifies the assembly process of optical devices and shortens the production time; (2) It avoids the problem of poor reliability caused by the assembly method of multiple gluing with multiple types of glue, thereby increasing the reliability of the product; (3) It can effectively solve the problem of difficult gluing of different optical devices (caused by insufficient glue dispensing space, insufficient suction position of the suction nozzle, etc.); (4) It can improve the production yield of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic flow chart of a method for preparing a photosensitive module provided in an embodiment of the present invention.

[0012] Figure 2 A schematic structural diagram of a light sensing module provided by an embodiment of the present invention.

[0013] Figure 3 for Figure 2 The structure diagram of the light sensing module shown is another perspective diagram after being cut along the AA' plane.

[0014] Figure 4 for Figure 2 The disassembled diagram of the light sensing module is shown.

[0015] Figure 5 for Figure 2 A disassembled diagram of the light sensing module from another perspective.

[0016] Description of reference numerals:

[0017] 10. Light sensing module; 11. Optical device I; 12. Optical device N (or II). DETAILED DESCRIPTION

[0018] The present invention provides a light sensing module and a method for manufacturing the same, as well as a TOF ranging device. To make the objectives, technical solutions, and effects of the present invention more clear and explicit, the present invention is further described below in detail. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0019] In a first aspect, an embodiment of the present invention provides a method for preparing a light sensing module, wherein the light sensing module includes N optical devices, where N is an integer greater than or equal to 2. Figure 1 , Figure 1 is a schematic flow chart of the preparation method, which may include the following steps S1-S3.

[0020] S1. Provide a mold I and an injection molding material I, heat the injection molding material I into a glassy state, and inject the glassy injection molding material I into the cavity of the mold I. After cooling and molding, demold the mold to obtain an optical device I.

[0021] S2. Provide a mold II and an injection molding material II, heat the injection molding material II into a glassy state, place the optical device I at a preset position I in the cavity of the mold II, and inject the glassy injection molding material II into the cavity of the mold II. After cooling and molding, demold the mold to obtain an integrated body I of the optical device I and a second optical device II.

[0022] S3. By analogy, a mold N and an injection molding material N are provided, the injection molding material N is heated into a glassy state, the integrated body N-2 is placed at a preset position N-1 in the cavity of the mold N, and the glassy injection molding material N is injected into the cavity of the mold N. After cooling and molding, the mold is removed to obtain an integrated body N-1 of the optical device I to the optical device N, where the integrated body N-1 is the photosensitive module.

[0023] In the embodiment of the present invention, multiple optical components are prepared and integrated by adopting an integrated process of multiple injection molding, which simplifies the assembly process, saves assembly workload, improves product yield, avoids optical components falling due to insufficient gluing, and enhances product reliability and yield.

[0024] In some embodiments, the glass transition temperature Tg of the injection molding material N is N Less than the glass transition temperature Tg of the injection molding material N-1 N-1 In this way, when the Nth injection molding is performed, there will be no thermal impact on the glassy injection molding material N, and there will be no thermal impact on the injection-molded optical device N-1 and the integrated body N-2 obtained by the N-1th injection molding. That is, when the Nth injection molding is performed, the integrated body N-2 will not be deformed due to the thermal impact of the glassy injection molding material N.

[0025] Furthermore, in some embodiments, Tg N-1 -Tg N ≥30°C. When the glass transition temperature difference between injection molding material N and injection molding material N-1 is within this range, the integrated body N-2 can better maintain its original form and function during the Nth injection molding.

[0026] For example, N=2; at this time, the structure of a light sensing module 10 obtained by the above preparation method is as follows Figure 2-5 As shown, it includes an optical device I 11 and an optical device N (or II) 12, which are integrally formed.

[0027] Furthermore, in some embodiments, the light sensing module 10 can be used to prepare a TOF distance measuring device. In this case, the optical device I 11 can be an optical lens.

[0028] In some embodiments, the optical device N may be a housing.

[0029] Furthermore, in some embodiments, the optical lens is made of a transparent resin or the like; and the housing is made of a material with low light transmittance, such as engineering plastics or industrial liquid crystal polymers.

[0030] In some embodiments, a robotic arm and a fixture are used to position the optical device I at the preset position I within the cavity of mold II, and to position the integrated body N-2 at the preset position N-1 within the cavity of mold N. That is, in step S2, the robotic arm and a fixture can be used to position the optical device I at the preset position I within the cavity of mold II; and in step S3, the robotic arm and a fixture can be used to position the integrated body N-2 at the preset position N-1 within the cavity of mold N. This further ensures that smaller optical devices can be precisely placed in the preset positions within the mold cavities, thereby ensuring the precise bonding between the optical devices and saving labor costs.

[0031] In some embodiments, in the optical module, the exposed areas of optical devices 1 through N-1 are greater than or equal to the effective operating areas of optical devices 1 through N-1. That is, when the optical device is placed in the mold cavity, a portion of it adheres to the mold cavity, while another portion is exposed relative to the mold. After multiple injection molding cycles, each optical device in the integrated optical sensing module is partially exposed, and the optical device operates through its exposed area or a portion of the exposed area.

[0032] In the second aspect, an embodiment of the present invention provides a photosensitive module, which is prepared by the preparation method described in any one of the first aspects. The multiple optical devices in the photosensitive module are integrally formed, so the fit between the optical devices can better meet the requirements of accuracy and bonding strength, thereby avoiding the risk of the optical device falling. By setting a cavity for the optical device used as a shell in the photosensitive module, when the photosensitive module is used in conjunction with a chip, the chip on the substrate can be directly covered by the cavity and glued and assembled into an optoelectronic product (such as a TOF ranging device), thereby avoiding the risk of the entire product being scrapped due to injection molding failure when performing injection molding on a substrate provided with a chip, thereby increasing the production yield of the product and reducing the production cost of the product. For example, as Figure 2-5 As shown, the light sensing module 10 can be composed of an optical device I11 and an optical device II12, which are integrally formed. In some embodiments, the light sensing module 10 can be used to prepare a TOF distance measurement device. In this case, the optical device I11 can be an optical lens; the optical device II12 can be a housing.

[0033] In a third aspect, an embodiment of the present invention provides a TOF ranging device, comprising: a substrate; a laser emitting chip, attached to the substrate, for emitting a light signal; the light sensing module described in the second aspect, disposed on the substrate, for calibrating the light signal of the acquired object and transmitting the calibrated light signal to the object to be measured; and a signal processing chip, attached to the substrate and electrically connected to the light sensing module, for receiving the light signal reflected by the object to be measured, and calculating the distance of the object to be measured based on the light signal reflected by the object to be measured.

[0034] For example, the laser emission chip and / or the signal processing chip may be attached to the substrate by glue.

[0035] In summary, the present invention provides a photosensitive module and a preparation method thereof, and a TOF ranging device. The preparation method of the photosensitive module adopts multiple injection molding to integrate multiple optical components into an integrated photosensitive module, thereby simplifying the device assembly process and shortening the production time; increasing the reliability of the optical device and the photosensitive module; and effectively solving the problem of difficult gluing of different optical devices; and improving the production yield of the product.

[0036] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a light sensing module, characterized in that: The light sensing module is used in a TOF distance measuring device. The light sensing module includes N optical devices, where N is an integer greater than or equal to 2. The preparation method includes the following steps: S1. Providing a mold I and an injection molding material I, heating the injection molding material I into a glassy state, and injecting the glassy injection molding material I into the cavity of the mold I. After cooling and molding, the mold is removed to obtain an optical device I; the optical device I is an optical lens; S2. Providing a mold II and an injection molding material II, heating the injection molding material II into a glassy state, placing the optical device I in a preset position I within the cavity of the mold II, and injecting the glassy injection molding material II into the cavity of the mold II. After cooling and forming, demolding is performed to obtain an integrated body I of the optical device I and a second optical device II; S3. Similarly, a mold N and an injection molding material N are provided, the injection molding material N is heated into a glassy state, the integrated body N-2 is placed in a preset position N-1 in the cavity of the mold N, and the glassy injection molding material N is injected into the cavity of the mold N. After cooling and forming, the mold is removed to obtain an integrated body N-1 of the optical devices I to N, where the integrated body N-1 is the light sensing module; The optical device N is a housing; The exposed areas of the optical devices 1 to N-1 are respectively greater than or equal to the effective working areas of the optical devices 1 to N-1. When the optical device is placed in the cavity of the mold, a part of it fits with the cavity of the mold and the other part is exposed relative to the mold. After multiple injection moldings are completed, a part of each optical device in the one-piece integrated photosensitive module is exposed, and the optical device works through its exposed area or part of the exposed area.

2. The preparation method according to claim 1, wherein The glass transition temperature TgN of the injection molding material N is lower than the glass transition temperature TgN-1 of the injection molding material N-1.

3. The preparation method according to claim 2, characterized in that: TgN-1-TgN is greater than or equal to 30°C.

4. The preparation method according to claim 1, wherein The material of the optical lens is transparent resin; And / or the material of the shell is engineering plastic or industrial liquid crystal polymer.

5. The preparation method according to any one of claims 1 to 3, characterized in that A robotic arm is used in conjunction with a fixture to place the optical device I at a preset position I in the cavity of the mold II, and the integrated body N-2 is placed at a preset position N-1 in the cavity of the mold N.

6. A light sensing module, characterized in that: The method is as described in any one of claims 1 to 5.

7. A TOF ranging device, characterized in that: include: substrate; A laser emitting chip is attached to the substrate and is used to emit light signals; The light sensing module according to claim 6, provided on the substrate, for calibrating the light signal and transmitting the calibrated light signal to the object to be measured; and a signal processing chip, which is attached to the substrate and is used for receiving the light signal reflected by the object to be measured and calculating the distance of the object to be measured according to the light signal reflected by the object to be measured.

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