Optical sensing device and method for manufacturing the same

Abstract

This invention relates to a photosensitive device and a method for manufacturing the same. The photosensitive device includes a substrate, at least one light-emitting element, and a photosensitive element. The light-emitting element emits light, and the photosensitive element receives diffusely reflected light after the light has been diffusely reflected by an external object. Furthermore, the light-emitting element and the photosensitive element are individually and separately mounted on the substrate.

Description

Technical Field

[0001] This invention relates to a photosensitive device and its manufacturing method, and more particularly to a photosensitive device and its manufacturing method that have multiple combination flexibility and measurement accuracy. Prior Technology

[0002] Non-invasive blood glucose testing technology is a method for measuring blood glucose levels without piercing the skin or extracting blood samples. Such technologies are of significant value in reducing inconvenience for patients with diabetes and increasing the frequency and convenience of blood glucose monitoring. Near-infrared Spectroscopy (NIRS) blood glucose testing technology utilizes a non-invasive optical detection method. It applies near-infrared light with wavelengths ranging from 700 nanometers (nm) to 2500 nanometers (nm). Infrared light in this wavelength range can be absorbed and scattered by components such as water, fat, and protein in tissues. By measuring the changes in absorption, reflection, and scattering of infrared light before and after irradiation of human tissues, the technology infers the blood glucose concentration within the tissues.

[0003] Figure 1 shows a cross-sectional schematic diagram of a conventional near-infrared blood glucose detection device 1. Conventional blood glucose detection devices are typically multi-chip modules 10. In manufacturing a multi-chip module, several photosensitive elements and several light-emitting elements are die-bonded onto a common conductive substrate. Then, through processes such as wire bonding, film lamination, light-blocking element fabrication, and dicing, several multi-chip modules are formed. Finally, the multi-chip modules 10 are mounted onto a printed circuit board 20. Each multi-chip module 10 includes a photosensitive element 11 and several light-emitting elements 12 die-bonded onto a conductive substrate 13. A light-blocking element 14 is designed between each photosensitive element 11 and each light-emitting element 12.

[0004] In the conventional blood glucose monitoring device 1 shown in Figure 1, the light-blocking element 14 is designed as a semi-cut and dispensing structure. After the multi-chip module 10 completes the encapsulation process of the protective layer 15 and the optical thin film cover plate 16, the package is cut between the light-emitting element and the photosensitive element in a semi-cut manner to form the groove for the light-blocking element. Then, the groove is filled with adhesive to form the light-blocking element 14. One of the disadvantages of the conventional blood glucose monitoring device 1 is that the light-blocking element 14 only exists between the photosensitive element 11 and the light-emitting element 12, and can only block the light transmission between the photosensitive element and the light-emitting element. There is no light-blocking element design around the periphery of the multi-chip module 10, so it cannot block the entry of ambient light, nor can it prevent the light-emitting element from leaking to an unintended external environment. Moreover, the conventional semi-cut and dispensing process also has disadvantages such as complex process, low yield, slow production, and high cost.

[0005] Furthermore, since the manufacturing of a multi-chip module involves bonding several photosensitive elements and several light-emitting elements onto a common conductive substrate, and the configuration of each chip in the multi-chip module is fixed after processes such as wire bonding and dicing, if any chip is found to be defective during the process, then no chip in the multi-chip module can be replaced, and the entire module can only be discarded, with no possibility of replacement.

[0006] Please refer to Figures 2A and 2B together. These figures illustrate that in conventional blood glucose monitoring devices, the multi-chip module 10 may be worn too loosely or too tightly against the user's body tissue due to variations in user operation. As shown in Figure 2A, if the blood glucose monitoring device is too loose against the body tissue, the multi-chip module 10 may experience light signal loss. On the other hand, as shown in Figure 2B, if the blood glucose monitoring device is too tight against the body tissue, the multi-chip module 10 excessively compresses the body tissue, forcing glucose 30 within the body tissue to be expelled to other locations within the body tissue. This results in a decrease in blood glucose concentration near the measured area, indirectly leading to distorted measurement results and affecting measurement accuracy. To overcome these problems, the industry urgently needs an innovative blood glucose monitoring device and its manufacturing method to improve these issues. Summary of the Invention

[0007] The main purpose of this invention is to provide an innovative optical sensing device and its manufacturing method, which improves the following problems of the prior art: (1) complex process, low yield, slow production and high cost (2) fixed module matching and low flexibility (3) inability to accurately interpret signals and affect measurement accuracy.

[0008] To achieve the above objectives, the present invention provides a photosensitive device comprising a substrate, at least one light-emitting element, and a photosensitive element. The light-emitting element emits light, and the photosensitive element receives diffusely reflected light after the light has been diffusely reflected by an external object. Furthermore, the light-emitting element and the photosensitive element are individually and separately mounted on the substrate.

[0009] In one embodiment of the photosensitive device of the present invention, at least one light-blocking element is included, which surrounds at least one light-emitting element and a photosensitive element to prevent the light emitted by the at least one light-emitting element from leaking out of the photosensitive device, and also to prevent ambient light and the light from being directly received by the photosensitive element without reflection.

[0010] In one embodiment of the photosensitive device of the present invention, the material of the light-blocking element is selected from one or a combination of thermoplastic polymers, carbon fiber materials, and ceramic materials.

[0011] In one embodiment of the photosensitive device of the present invention, the transmittance of the light-blocking element is not greater than 5%.

[0012] In one embodiment of the photosensitive device of the present invention, the reflectivity of the light-blocking element is not less than 95%.

[0013] In one embodiment of the photosensitive device of the present invention, a pressure-sensitive element is further included, disposed on the light-blocking element, for sensing an external force applied to the photosensitive device.

[0014] In one embodiment of the photosensitive device of the present invention, the pressure-sensitive element senses that the external force applied to the photosensitive device is less than 100 Newtons (N).

[0015] In one embodiment of the photosensitive device of the present invention, an optical thin film cover plate is further included to cover the photosensitive element, selectively allowing only a specific wavelength of light to pass through while blocking other wavelengths of light from passing through.

[0016] To achieve the above objectives, the present invention provides a method for manufacturing a photosensitive device, comprising: providing a substrate; providing at least one light-emitting element; providing a photosensitive element; and individually and separately mounting at least one light-emitting element and a photosensitive element onto the substrate, wherein the photosensitive element is used to receive diffusely reflected light after light emitted by at least one light-emitting element has been diffusely reflected by an external object.

[0017] In one embodiment of the manufacturing method of the photosensitive device of the present invention, it is further included to provide at least one light-blocking element to surround at least one light-emitting element and photosensitive element, so as to prevent the light emitted by at least one light-emitting element from leaking out of the photosensitive device, and also to prevent ambient light and the light from being directly received by the photosensitive element without reflection.

[0018] In one embodiment of the method for manufacturing the photosensitive device of the present invention, a pressure-sensitive element is provided and disposed on at least one light-blocking element for sensing an external force applied to the photosensitive device.

[0019] In one embodiment of the manufacturing method of the photosensitive device of the present invention, the steps of providing at least one light-emitting element and providing a photosensitive element are: fixing at least one light-emitting chip and a photosensitive chip onto a conductive substrate; providing a protective layer to cover at least one light-emitting chip and a photosensitive chip; and cutting the conductive substrate to individually and separately form at least one light-emitting element and a photosensitive element.

[0020] In one embodiment of the manufacturing method of the photosensitive device of the present invention, the method further includes the step of providing an optical thin film cover plate to cover the protective layer before cutting the conductive substrate.

[0021] Other objects of the present invention, as well as the technical means and embodiments of the present invention, will be understood by those skilled in the art upon referring to the drawings and the embodiments described below. Simple Explanation of the Diagram

[0022] Figure 1 is a schematic cross-sectional view of a conventional near-infrared blood glucose detection device; Figures 2A and 2B are schematic diagrams illustrating the states of a multi-chip module in a conventional blood glucose testing device due to the user wearing it too loosely and too tightly. Figure 3 is a schematic diagram of the structure of the photosensitive device in one embodiment of the present invention; Figure 4 is a schematic diagram of the combination of the light-emitting element, the photosensitive element, and the light-blocking element in an embodiment of the present invention; Figure 5 is a flowchart of the manufacturing process of the photosensitive device in one embodiment of the present invention; Figure 6 is a schematic diagram of the fabrication of a light-emitting element and a photosensitive element in an embodiment of the present invention; and Figure 7 is a schematic diagram of the fabrication of the light-emitting element and the photosensitive element in another embodiment of the present invention. Implementation

[0023] The present invention will be explained below through embodiments. These embodiments are not intended to limit the implementation of the invention to any specific environment, application, or special method as described in the embodiments. Therefore, the descriptions of the embodiments are for illustrative purposes only and are not intended to limit the invention. It should be noted that in the following embodiments and drawings, devices not directly related to the present invention have been omitted and are not shown, and the dimensional relationships between the devices in the drawings are for ease of understanding only and are not intended to limit the actual scale.

[0024] Please refer to Figure 3, which is a schematic diagram of the structure of a photosensitive device in one embodiment of the present invention. One difference between the photosensitive device of the present invention and conventional devices is that the photosensitive device of the present invention uses a single-chip module instead of a conventional multi-chip module. Both the light-emitting element that provides the light source and the photosensitive element that receives light and generates electrical signals are structurally independently designed as a single-chip module, thereby improving the flexibility of module configuration and the possibility of replacing manufacturing defects. The details are as follows.

[0025] As shown in Figure 3, the photosensitive device 100 of the present invention includes a substrate 110, two light-emitting elements 120, a photosensitive element 130, and several light-blocking elements 140. Each light-emitting element 120 includes a light-emitting diode chip 122 and a conductive substrate 124. The light-emitting diode chip 122 is mounted on and electrically connected to the conductive substrate 124. The light-emitting diode chip 122 emits light of a specific wavelength. In the case of the photosensitive device of the present invention, which can be specifically applied to blood glucose concentration detection, the light-emitting diode chip 122 can emit near-infrared light with wavelengths ranging from 700 nanometers (nm) to 2500 nanometers (nm). In other embodiments, light-emitting diode chips of different wavelengths can be replaced according to different detection requirements. It should be noted that the light-emitting element 120 further includes a protective layer 126 covering the light-emitting diode chip 122 to protect the chip and form a light-emitting package. Furthermore, in the embodiment shown in FIG3, the light-emitting element 120 further includes an optical thin film cover plate 128 to cover the protective layer 126 and the light-emitting diode chip 122, wherein the optical thin film cover plate 128 includes a glass cover plate 128a and an optical coating 128b.

[0026] Secondly, the photosensitive element 130 includes a photosensitive chip 132 and a conductive substrate 134. The photosensitive chip 132 is mounted on the conductive substrate 134 and electrically connected to it. Light emitted by the light-emitting element 120 is diffusely reflected by an external object, such as human tissue. This diffusely reflected light is received by the photosensitive chip 132 of the photosensitive element 130, generating a corresponding electrical signal. After system conversion, the corresponding blood glucose concentration, for example, within the human tissue, is obtained. Similarly, the photosensitive element 130 further includes a protective layer 136 covering the photosensitive chip 132 to protect the chip and form a photosensitive package. Furthermore, the photosensitive element 130 also includes an optical thin film cover 138 to cover the protective layer 136 and the photosensitive chip 132. The optical thin film cover 138 includes a glass cover 138a and an optical coating 138b. It should be noted that this optical thin film cover 138 can be an optical filter, such as a band pass filter (BPF), used to selectively allow only light within a specific wavelength range to pass through, while blocking or reducing the transmission of other wavelengths of light.

[0027] Furthermore, unlike prior art, the light-emitting element 120 and the light-sensing element 130 of the present invention are separate individual components, which are individually and separately mounted onto the substrate 110, whose surface has printed circuits, during the subsequent manufacturing process of the light-sensing device 100. Therefore, different numbers of light-emitting elements 120 and light-sensing elements 130 can be installed according to different final requirements of the light-sensing device 100, providing flexibility in product configuration. Even if any of the components is defective, the light-sensing device 100 of the present invention still has the possibility of replacing the defective component on the substrate 110. A detailed description of this part will be provided in the subsequent manufacturing method of the light-sensing device 100 of the present invention.

[0028] Referring again to Figure 3, another difference between the present invention and conventional devices is that the photosensitive device 100 of the present invention further includes at least one light-blocking element 140, which surrounds the light-emitting element 120 and the photosensitive element 130 to prevent light emitted by the light-emitting element 120 from leaking out of the photosensitive device 100, and also to prevent ambient light and such light from being directly received by the photosensitive element 130 without reflection from external substances (such as human tissue). Specifically, please refer to Figure 4, which shows that the shape of the light-blocking element can be designed in different shapes according to requirements, such as, but not limited to, U-shaped and U-shaped light-blocking elements. In the embodiment shown in Figure 4, one U-shaped light-blocking element 140 and two U-shaped light-blocking elements 140 are used to completely surround the two light-emitting elements 120 and one photosensitive element 130, achieving the aforementioned purpose of preventing light leakage and blocking ambient light and light of specific wavelengths from entering the photosensitive element 130. The height of the light-blocking element 140 may be, but is not limited to, greater than or equal to 0.4 mm, and its width may be not less than 0.1 mm. Secondly, the material constituting the light-blocking element 140 may be selected from one or a combination of thermoplastic polymers, carbon fiber materials, and ceramic materials, wherein the thermoplastic polymers may include polystyrene, low-density polyethylene, polyacetal, polylactic acid, acrylonitrile-butadiene-styrene copolymer, etc. Furthermore, the transmittance of the aforementioned light-blocking element material is not greater than 5% or the reflectance is not less than 95%, in order to achieve the effect of blocking light.

[0029] In a preferred embodiment of the present invention, to avoid the problem of the photosensitive device being too loose or too tight between the device and the user's body tissue due to differences in user operation during actual application, the photosensitive device 100 further includes a pressure-sensitive element 150, which can be adhesively disposed on the light-blocking element 140 to sense the external force applied to the photosensitive device 100. Specifically, when the photosensitive device 100 is too loose between the photosensitive device and the body tissue, the pressure-sensitive element 150 may sense that the external force applied to the photosensitive device 100 is zero or close to zero. In this case, the photosensitive device 100 can issue a warning of being too loose in response to signal loss, reminding the user to readjust the wearing state. On the other hand, when the photosensitive device 100 is too tight between the photosensitive device and the body tissue, causing the pressure-sensitive element 150 to sense that the external force applied to the photosensitive device 100 exceeds the preset value set by the system, for example, it can be, but is not limited to, 100 Newtons (N). At this time, the light sensor 100 can issue a corresponding warning when the device is worn too tightly, reminding the user to readjust the wearing position in order to detect the correct measurement value, such as blood glucose concentration.

[0030] Please refer to Figure 5 below, which shows a flowchart of manufacturing a photosensing device according to the present invention. In step 501, a substrate including a printed circuit is provided. In step 502, according to the requirements of the photosensing device, at least one light-emitting element is provided to provide light in a specific wavelength band. In step 503, according to the requirements of the photosensing device, a photosensing element is provided to receive diffusely reflected light from the light emitted by the light-emitting element after being diffusely reflected by an external object. In step 504, according to the requirements of the photosensing device, a specific number of individual and separate light-emitting elements and photosensing elements are mounted on the substrate. In step 505, according to the requirements of the photosensing device, a specific number of light-blocking elements are provided to surround the aforementioned light-emitting elements and photosensing elements, preventing light emitted by the light-emitting elements from leaking out of the photosensing device, and also preventing ambient light and such light from being directly received by the photosensing element without reflection. In step 506, a pressure-sensitive element is provided, disposed on the light-blocking elements, for sensing external forces applied to the photosensing device.

[0031] The following describes, using two embodiments, how the present invention manufactures individual and separate light-emitting elements and light-sensing elements in a photosensitive device. Referring to Figure 6, process 6A shows several light-emitting diode (LED) chips 602 and several photosensitive chips 604 being fixed to a conductive substrate 606 using die bonding or surface mount technology. Next, in process 6B, wire bonding is performed to electrically connect the LED chips 602 and photosensitive chips 604 to the conductive substrate 606. Next, in process 6C, a protective layer 608 is molded to cover the LED chips 602 and photosensitive chips 604. Next, in process 6D, an optical film cover plate 610 with an optical film is provided over the protective layer 608, so that the optical film cover plate 610 simultaneously covers both the LED chips 602 and the photosensitive chips 604. Subsequently, in process 6E, the conductive substrate 606 is cut using a cutting device to form individual, separate, and pre-packaged light-emitting elements 612 and photosensing elements 614. Next, in process 6F, according to the design requirements of the photosensing device, a certain number of individual, separate light-emitting elements 612 and photosensing elements 614 are assembled onto the printed circuit board 616. In process 6G, light-blocking elements 618 of appropriate number and structural shape are used to cover the entire periphery of the light-emitting elements 612 and photosensing elements 614. Finally, in process 6H, pressure-sensitive elements 620 are bonded to the assembled light-blocking elements 618 to complete the photosensing device 600 of the present invention.

[0032] Please refer to Figure 7, which illustrates another embodiment of how the present invention manufactures individual and separate light-emitting elements and light-sensing elements. First, similarly, in process 7A, several light-emitting diode (LED) chips 702 and several light-sensing chips 704 are fixed to a conductive substrate 706 using die bonding or surface mount technology. Unlike the previous embodiment, in this embodiment, an optical thin film has been attached to the surface of the light-sensing chip 704, which can filter light of a specific wavelength range from being received by the light-sensing chip 704. Therefore, the subsequent process of attaching an optical thin film cover plate can be saved. Next, in process 7B, wire bonding is performed to electrically connect the LED chips 702 and the light-sensing chips 704 to the conductive substrate 706. Next, in process 7C, a protective layer 708 molding process is performed to cover the LED chips 702 and the light-sensing chips 704 with the protective layer 708. Next, in process 7D, the conductive substrate 706 is cut using a cutting device to form individual, separate, and packaged light-emitting elements 712 and light-sensing elements 714. Next, in process 7E, according to the design requirements of the light-sensing device, a certain number of individual, separate light-emitting elements 712 and light-sensing elements 714 are assembled onto the printed circuit board 716. Then, in process 7F, a light-blocking element 718 is used to cover the entire periphery of the light-emitting elements 712 and light-sensing elements 714. Finally, in process 7G, ​​a pressure-sensitive element 720 is bonded to the light-blocking element 718 to complete the light-sensing device 700 of this invention.

[0033] As mentioned above, this invention utilizes a "single-chip module" approach for light-emitting and photosensitive elements. Depending on the requirements of different applications, different numbers of module elements can be freely selected and combined with different structural shapes, such as U-shaped and M-shaped modular light-blocking elements, all integrated on a printed circuit board. This provides flexibility in various combinations without limitations on quantity, position, or arrangement. Furthermore, if any module is defective, the photosensitive device of this invention can be repaired by replacing it with a good one, eliminating the need to discard the entire module as in traditional methods. Therefore, the photosensitive device of this invention can overcome the shortcomings of traditional multi-chip module blood glucose monitoring devices. The modified design can (1) improve light-blocking efficiency due to the complete light-blocking element design; (2) improve module yield by replacing defective products; (3) increase production speed through the single-chip module design; (4) reduce overall device manufacturing costs due to the flexibility of module combinations; and (5) increase module combination flexibility, providing multiple options to meet user needs. More specifically, the photosensitive device of the present invention has a pressure-sensitive element that can provide force sensing, enabling the non-invasive blood glucose detection module of the present invention to filter or correct measurement data and improve the accuracy of blood glucose detection.

[0034] The above embodiments are merely illustrative of the implementation of the present invention and to explain its technical features, and are not intended to limit the scope of protection of the present invention. Any changes or equivalent arrangements that can be easily made by those skilled in the art are within the scope of the present invention, and the scope of protection of the present invention shall be determined by the scope of the patent application.

[0035] 1. Blood glucose testing device 10+ chip modules 11. Photosensitive element 12 Light-emitting elements 13 Conductive substrate 14 light-blocking elements 15 Protective Layers 16 Optical thin film cover plate 20 Printed Circuit Boards 30 glucose 100 Light Sensing Devices 110 substrate 120 Light-emitting element 122 Light Emitting Diode Chip 124 conductive substrate 124 126 Protective Layer 128 Optical Thin Film Cover Plate 128a Glass Cover 128b optical thin film 130 Photosensitive element 132 Photosensitive Chip 134 Conductive substrate 136 Protective Layer 138 Optical Thin Film Cover Plate 138a Glass Cover 138b optical coating 140 light-blocking element 150 pressure-sensitive element 600 light sensing devices 602 Light Emitting Diode Chip 604 photosensitive chip 606 conductive substrate 608 protective layer 610 Optical Thin Film Cover Plate 612 Light-emitting element 614 Photosensitive element 616 Printed Circuit Board 618 light-blocking element 620 pressure-sensitive element 700 light sensing device 702 Light Emitting Diode Chip 704 photosensitive chip 706 conductive substrate 708 protective layer 712 Light-emitting element 714 Photosensitive element 716 Printed Circuit Board 718 light-blocking element 720 pressure-sensitive element

Claims

1. A photosensing device, comprising: a substrate; at least one pre-packaged light-emitting element for emitting light; a pre-packaged photosensing element for receiving diffusely reflected light after the light has been diffusely reflected by an external object; and a plurality of modular light-blocking elements surrounding the at least one pre-packaged light-emitting element and the pre-packaged photosensing element to prevent the light emitted by the at least one pre-packaged light-emitting element from leaking out of the photosensing device, and also to prevent ambient light and the light from being directly received by the pre-packaged photosensing element without reflection, wherein... The at least one packaged light-emitting element and the packaged photosensitive element are individually and replaceably mounted on the substrate.

2. The photosensitive device as claimed in claim 1, wherein the material of the modular light-blocking elements is selected from one or a combination thereof of thermoplastic polymers, carbon fiber materials, and ceramic materials.

3. The light sensing device as claimed in claim 1, wherein the transmittance of the modular light-blocking elements is not greater than 5%.

4. The light sensing device as claimed in claim 1, wherein the reflectivity of the modular light-blocking elements is not less than 95%.

5. The light sensing device as claimed in claim 1 further includes an optical thin film cover plate covering the light sensing element, selectively allowing only a specific wavelength of light to pass through while blocking other wavelengths of light from passing through.

6. A method of manufacturing a photosensitive device, comprising: providing a substrate; providing at least one pre-packaged light-emitting element; providing a pre-packaged photosensitive element; individually and replaceably mounting the at least one pre-packaged light-emitting element and the pre-packaged photosensitive element onto the substrate, wherein the pre-packaged photosensitive element is used to receive diffusely reflected light after light emitted by the at least one pre-packaged light-emitting element has been diffusely reflected by an external object; and providing a plurality of modular light-blocking elements surrounding the at least one pre-packaged light-emitting element and the pre-packaged photosensitive element to prevent the light emitted by the at least one pre-packaged light-emitting element from leaking out of the photosensitive device, and also to prevent ambient light and the light from being directly received by the pre-packaged photosensitive element without reflection.

7. A method for manufacturing a photosensitive device as claimed in claim 6, wherein the steps of providing at least one packaged light-emitting element and providing a packaged photosensitive element are: fixing at least one light-emitting chip and a photosensitive chip onto a conductive substrate; providing a protective layer to cover the at least one light-emitting chip and the photosensitive chip; and cutting the conductive substrate to individually and separately form the at least one packaged light-emitting element and the packaged photosensitive element.

8. The method of manufacturing the photosensitive device as described in claim 7 further includes the step of providing an optical thin film cover plate to cover the protective layer before cutting the conductive substrate.

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