TWI450157B - Integrated optical module and finger scanning apparatus using the same - Google Patents

Description

Integrated optical module and finger scanning device

The invention relates to an integrated optical module suitable for a finger sensing device, in particular to an integrated optical module for providing finger navigation and biometric scanning functions in a fingerprint imaging device.

Modern electronic devices are constantly moving toward miniaturization, and the diversity and complexity of the functions they provide are not comparable. Traditional human interface devices (HIDs), such as mouse and keyboard, have become apparently inadequate for use in the control interface of modern electronic devices with a variety of multimedia functions.

Therefore, the precise and intuitive miniaturized control interface that provides close human-computer interaction has been the research and development goal of the industry. In particular, new miniature personal electronic devices have been deeply integrated into modern daily life, and these devices have been applied in various environments, and their applicability has become particularly important. In particular, the human interface device used therein is not only precise and sensitive, but also compact and durable.

On the other hand, with the personalization of modern electronic devices, the information and information stored in them is increasingly private and important. Therefore, new personal electronic devices need to incorporate appropriate security mechanisms to protect such important information, especially in the case of lost theft, to limit the improper operation of others. Among them, human fingerprints are a unique biological feature and have been used for identification purposes for a long time. Therefore, it is desirable to incorporate fingerprint scanning/recognition functions into modern small electronic devices to manage data access to enhance security.

Optical finger navigation (OFN) technology has the above characteristics of precision, compactness and high credibility. Therefore, it has its own The scanning function of the optical finger navigation device is ideal for biometric applications. Specifically, the new miniature optical finger navigation device combines the sensitivity and reliability of existing optical mice with less space constraints than traditional physical applications.

In general, an optical finger navigation device uses a light source and a series of associated optical lenses arranged to illuminate a sensing surface to produce a digital image, thereby forming the basis for motion data calculation. In particular, the small sensor in the navigation device can correspondingly generate a series of digital images by detecting the finger placed on the detection surface, and then process the data into relevant navigation signals. Manipulating electronic devices or creating interactions with electronic devices.

However, conventional optical finger navigation devices typically place illumination and imaging optics separately on their detection surface, taking up valuable space. Moreover, the separate optical design results in a less uniform illumination output over a wide area of the detection surface, which would negatively impact the performance of the optical finger navigation device. Also, finger navigation and fingerprinting operations typically require optical components of different characteristics. In general, optical lenses with wide-spanning linear arrays are more suitable for use with fingerprint recognition functions. On the other hand, optical lenses with point-concentrated detection arrays are more suitable for finger navigation applications. Therefore, separate placement of optical components within a single device for application to individual modes of operation is inefficient in terms of cost effectiveness and space utilization.

Therefore, the object of the present invention is to provide an integrated optical module capable of supporting the operation of fingerprint recognition and finger navigation, and at the same time having a light and small shape for use in a lower-profile package structure. . In addition, the present invention also proposes a compact and cost effective The finger sensing device has both fingerprint recognition and finger navigation functions, and is particularly suitable for small portable electronic devices.

The technical problem to be solved by the present invention is to provide an integrated optical module suitable for use in a finger sensing device. The integrated optical module is disposed between a window module and an electronic module to provide finger navigation and fingerprint recognition performance.

To achieve the above objective, the present invention provides an integrated optical module disposed between a window module having a contact surface and an electronic module having a light source and a light sensing unit. The integrated optical module includes an illumination portion and an imaging portion. The illumination portion includes a light guiding array for guiding incident light from the light source to be aligned with the window module at a predetermined incident angle; the imaging portion includes a microlens array disposed thereon for alignment The window module reflects light and faces the light sensing unit. The microlens array includes an elongated identification unit having a column of axes substantially perpendicular to the light guiding array; and a navigation unit coupled to the identification unit and juxtaposed with the column axis.

In addition, the technical problem to be solved by the present invention is to provide a finger scanning device that utilizes an integrated optical module to plan the performance of both finger navigation and fingerprint recognition.

In order to solve the above technical problem, according to one aspect of the present invention, a finger scanning device is provided, including a window module, an electronic module, and an integrated optical module. The window module has a contact surface that abuts a finger to be scanned; the electronic module includes a light source and a light sensing unit correspondingly arranged toward the window module; the integrated optical module is disposed Between the window module and the electronic module, the integrated optical module includes a An illumination unit, an imaging unit, an identification unit, and a navigation unit. The illumination portion has a light guiding array for guiding light from the light source to be aligned with the window module at a predetermined incident angle; the imaging portion has a microlens array disposed thereon for reflecting from The light of the window module faces the light sensing unit; wherein the microlens array comprises an elongated identification unit having a column of axes substantially perpendicular to the light guiding array, and a navigation unit coupled to the identification unit and juxtaposed with the column axis.

In accordance with one of the embodiments of the present invention, it is further provided that the illumination channel design can be used in a small, low profile optical package and that a projected projection pattern can be provided to evenly illuminate a wide scan area.

In order to further understand the technology, method and effect of the present invention in order to achieve the intended purpose, reference should be made to the detailed description and drawings of the present invention. The drawings and the annexed drawings are intended to be illustrative and not to limit the invention.

Referring to Figure 1, an exploded view of an integrated optical module incorporating an optical finger sensing device in accordance with the teachings of the present invention is shown. The integrated optical module 1 (or optical module for short) in this embodiment, together with the related optical sensor arrangement, can efficiently support the finger navigation for fingerprint recognition operation. From the bottom up, the optical finger sensing device includes an electronic module 4, an integrated optical module 1, and a window module 3 as an inductive package. The electronic module 4 has a light source 41 (refer to FIG. 2) and a light sensing unit 42. The integrated optical module 1 includes an illumination unit 11 and an imaging unit 12 correspondingly disposed above the electronic module 4; The module 3 has a contact surface at least partially located in the integrated light Learn above the module 1. The above components are arranged vertically as a low-profile compact package. In addition, the glazing shield 2 and the lower glazing member 5 are selectively applicable to the imaging portion 12 of the integrated optical module 1 to enhance the anti-crosstalk performance of the finger sensing device.

The conceptual operating principles of the optical finger sensing device of the present invention are as follows. Referring to FIG. 2 and FIG. 3, a side cross-sectional view of the finger sensing device and a perspective view of the integrated optical module 1 thereof are respectively shown. The integrated optical module 1 has a light source 41 and an illumination portion 11 close to the light source 41. The light source 41 may be one or more light emitting diodes that are provided to emit light toward the illumination portion 11 of the integrated optical module 1 for a predetermined area. The illuminating portion 11 of the optical module 1 is formed with a plurality of light guiding members 111a, 111b, 111c for guiding the light beam from the light source 41 toward the scanning surface (or the touch surface of the window module 3 according to a predetermined incident angle. ), to illuminate objects close to the touch surface. Through the scanning surface (or touch surface) of the window module 3, the user's finger can be placed thereon for scanning. The reflected light of the end face of the finger can be transmitted toward the image forming portion 12 of the optical module 1. The imaging unit 12 includes a micro lens array 121 for focusing and guiding the reflected light toward the light sensing unit 42 of the electronic module 4 .

In this embodiment, the optical module 1 has a substantially flat rectangular plate, and includes an illumination portion 11 and an imaging portion 12 respectively disposed on a defined X-Y plane (see FIG. 3). The optical module 1 of the present invention arranges the illumination portion 11 and the imaging portion 12 in a compact horizontal shape to help reduce the thickness of the module, so that the overall induction package can maintain a lower profile. The integrated optical module 1 can be made of polycarbonate (Polycarbonate, PC for short) or other suitable material that can transmit electromagnetic waves emitted by the electronic module 4. In addition, the optical module 1 can It is molded into a single-piece optical component by precision injection molding of plastic. The illumination unit 11 of the optical module 1 is provided with a light source 41 corresponding to the electronic module 4, and defines an illumination channel for transmitting a light beam from the light source 41 toward the window module 3 according to a suitable incident angle. The illumination channel includes a light guide array 111 containing the light guides 111a, 111b, 111c to illuminate the object to be scanned. Specifically, the light guiding members (or optical components) of the light guiding array 111 can utilize the principle of total internal reflection (TIR), or apply other suitable optical designs to guide the light of the light source 41. Facing the window module 3. Similarly, the imaging unit 12 of the optical module 1 is designed to correspond to the light sensing unit 42 of the electronic module 4, and includes an imaging channel that can guide the reflected light from the window module 3 (from the object to be scanned, The end face of the human finger faces the light sensing unit 42. In particular, the imaging channel can include a microlens array 121 designed to incorporate multiple lens elements to accommodate different modes of finger scanning operations, including fingerprint recognition and finger navigation.

The electronic module 4 typically includes a substrate (e.g., a circuit board, unlabeled) that is provided with the electronic components necessary to achieve the optical scanning function. The electronic module 4 can include a light source 41 (refer to the light source elements 41a, 41b, 41c shown in FIG. 4) and a light sensing unit 42. A photo shield structure 43 is preferably disposed between the light source 41 and the light sensing unit 42 to prevent potential interference of an optical crosstalk effect. The light shielding structure 43 can serve as a structural boundary to divide the electronic module 4 into an illumination area and a sensing area.

In this embodiment, the light source 41 is disposed on the substrate (or the circuit board) and located on one side of the light shielding structure 43 and may include one or more light emitting diodes as the light emitting elements. In one of the ways, the light source 41 can be composed of a single light-emitting element having a sufficient output function. High power light in this situation The source can be arranged and become a wide-angle light guiding array of the optical module 1 to evenly scatter light toward a predetermined illumination area. Thereby, the light emitted by the light source 41 can be guided to the window module 3 and projected onto the object to be scanned. In another alternative embodiment, the light source 41 can include a plurality of light emitting elements 41a, 41b, 41c arranged in an array of illumination. The design of the plurality of light-emitting elements can reduce the output requirements of a single light-emitting element, and thus can operate flexibly and save energy. This feature is especially important for small handheld devices that use portable batteries. Specifically, a plurality of low-power light-emitting elements may be arranged in an array of light sources, each of which is separately planned to project light to a predetermined area. The degree of overlap of the illuminating elements can be flexibly arranged to suit a particular operational need. Furthermore, each of the separate illuminating elements can be programmed to be activated individually or in accordance with a particular mode of operation, depending on the actual needs. Thereby reducing the repetitive energy loss.

In the array of light sources, the activation and operation of each individual light-emitting element can be appropriately adjusted according to a particular mode of operation. For example, not all types of imaging applications require all of the lighting elements to be activated at the same time. By way of example, fingerprint recognition applications typically require simultaneous activation of all of the light-emitting elements in the array of light sources to produce sufficient horizontal illumination across the touch surface of the window module 3 over a wide scan area (along the x-axis). On the other hand, finger navigation applications operate with a change in the directional vector of the reflected light signal, requiring only a lower level of light output and a narrower but higher range of illumination (higher means along y axis). Incidentally, the application of finger navigation does not require that all of the light-emitting elements be activated at the same time. Thus, when performing a particular mode of operation that does not require simultaneous activation of all of the array of light sources, the electronic module 4 can be arranged to activate only a portion of the array of light sources 41 to illuminate a particular area of the touch surface. Furthermore, as appropriate A multi-element array of light sources enhances uniform light output intensity over a specified illumination area. Therefore, this is a preferred choice for this embodiment.

For example, the present embodiment utilizes a light source array comprising three light emitting elements arranged in a single column (as shown in FIG. 4). When operating in the fingerprint recognition mode, all three of the light-emitting elements in the array are activated to produce sufficient brightness to cover a wider strip area on the touch surface of the window module 3.

On the other hand, when operating in the finger navigation mode, only the central light-emitting element 41b is required to illuminate the central portion of the contact (scanning) surface. Therefore, the change in the directivity vector at the touch surface (corresponding to the movement of the finger end) is directed toward the microlens array 121 of the optical module 1. The microlens array 121 is arranged to focus the reflected light from the window module 3 on the light sensing unit 42 of the electronic module 4 to further process the signal, the details of which will be described later.

The light sensing unit 42 is disposed in the detection area of the electronic module 4 and located on the other side of the light shielding structure 43 and may include one or more photosensitive members to generate a two-dimensional image of the scanned object. Suitable photosensitive members may include dual or quad flat no no leads (DFN/QFN) photodiodes. Preferably, the light sensing unit 42 can include a plurality of photosensitive members arranged in a pair of sensing arrays that should be in the microlens array 121. Moreover, the electronic module 4 can include a preferably designed base member in a plane facing the window to provide a secure structural support for the optical module 1. As shown in this embodiment, the annular base member (such as the square protrusion portion of FIG. 1 and the light blocking structure 43 is a part thereof) is arranged to surround the light sensing element 42 to the electronic module 4 for sensing. On the area. Such a closed loop structure can be used not only as a microlens tray to hold the optical module 1, but also as an extended photo shield to more effectively prevent crosstalk.

The window module 3 can be an upper housing designed as the optical finger sensing device. The window module 3 includes a touch surface (typically its top surface) for the finger to be placed thereon and slid over for detection. Specifically, the touch surface can transmit light of a specific wavelength range as a scanning window, and the specific wavelength range corresponds to the output of the light source by the electronic module 4.

The touch surface can be flat, or preferably, with a slight depression. For example, a convex curvature at the top of the touch surface helps to increase the sensing area, which focuses on capturing a finger image that is pressed against it. The window module 3 may be formed of glass, or other wear resistant material may transmit light from the light source 41. Furthermore, the scanning window may be provided as a separate optical component to the window module 3 or may be part of the integrally formed window module 3. For example, the window module 3 may be made entirely of a transparent material. Correspondingly, a suitable coating material can be applied to the body of the window module 3 to expose only the desired transparent portion to form the scanning window. The scanning window may be elongated and have an area smaller than one of the end faces of the finger. Furthermore, at least a portion of the scanning window (which has a longitudinal axis) can be preferably widened in one direction which is perpendicular to its own direction. The widened window area preferably corresponds to the microlens array 121 of the optical module 1 to aid in the light detection performance of the finger navigation module.

The optical and structural arrangement of the illumination portion 11 of the optical module 1 in this embodiment is set to correspond to the arrangement of the light source 41. The illumination unit 11 and the light source 41 cooperatively define an illuminating channel. Referring to FIG. 4 and FIG. 6 in particular, different schematic views of the illumination unit 11 of the integrated optical module of the present invention are shown. In order to obtain a clear fingerprint, the miniaturized light guiding elements of the illumination channel are specifically arranged to create an inclined collimated beams of light integrated into the desired projection pattern. The scanning window of the window module 3 is illuminated. Furthermore, the illumination channel can be established by a light guiding array comprising a plurality of optical elements for uniformly projecting light from the light source 41 to the scanning window of the window module 3. Specifically, the present embodiment utilizes a light guiding array 111 to include three adjacently arranged light guiding members (for example, prism members) 111a, 111b, 111c whose light emitting faces are directed toward the image forming portion 12. In this embodiment, the optical members composed of the light guiding members (for example, 稜鏡) 111a, 111b, 111c are arranged in a single columnar configuration having a row axis, and the column The shaft extends generally parallel to the elongating axis of the scanning window. The light guiding array according to the embodiment can adopt a congregated light source on the electronic module 4 to save space, and can also uniformly illuminate a wide area of the scanning surface. Alternatively, as shown in FIG. 6, the light guiding array may also be arranged to be horizontally spread along the scanning window. This constructs a well-controlled illumination pattern across a wider pitch scanning surface. Wherein the light guiding array comprises at least three optical elements arranged around the microlens array.

The imaging portion 12 of the optical module 1 includes a microlens array 121 that is capable of guiding and focusing the reflected light (the end face of the finger scanned from the window module 3) toward the light sensing unit 42. The imaging unit 12 of the optical module 1 and the light sensing unit 42 of the electronic module 4 collectively construct an image channel defining the above, and can guide the reflected light from the scanned object to the electronic module 4 to capture the image. Fig. 5 shows a close-up view of the image forming portion 12 of the optical module 1 of the present invention. In this embodiment, the microlens array 121 is disposed in a central region of the rectangular optical module board, and includes an identification lens unit 121a and an associated navigation lens unit 121b. The identification lens unit 121a includes a plurality of microlens elements arranged in an elongated array of columns. The elongated identification lens unit 121a has an axis extending longitudinally along the x-axis. Preferably, the extension (or column axis) of the axis of the identification lens unit 121a is substantially perpendicular to the light exit surface of the light guides 111a, 111b, 111c and substantially parallel to the scan window of the window module 3. On the other hand, the navigation lens unit 121b includes a concentrated focusing lens that is coupled to the identification lens unit 121a and is perpendicular to the longitudinal axis. In the present embodiment, the lens elements of the navigation lens unit 121b are arranged adjacent to the central portion of the elongated identification lens unit 121a by a single microlens to cover one or more associated optical diodes.

The navigation lens unit 121b is preferably arranged with a window region corresponding to the window module 3 being stretched (for example, alignably disposed below the central portion of the widened window region) to establish a wider field of view. Measure finger movements in finger navigation operations. Please note that although the central position of the navigation lens unit 121b and the widened navigation window discussed herein are more suitable for general navigation operations. However, the clear location and arrangement of the navigation lens unit 121b, as well as its associated navigation window, can still be arranged in other configurations to suit a particular design and/or operational need. For example, the navigation lens unit 121b may be arranged to be skewed toward the right end of the identification lens unit 121a (in the positive x-axis direction) to be more suitable for the finger navigation mode of the right thumb. Furthermore, the imaging portion 12 of the optical module 1 can be provided with a shielding structure to reduce the potential interference of the optical crosstalk effect. For example, a non-transmissive coating may be applied to the imaging portion 12 along the microlens array 121. Applications of these light blocking layers (or anti-crosstalk layers) may include electro-less plating and/or other suitable techniques.

The integrated optical module of the present invention, unlike conventional optical design systems, utilizes separate illumination and imaging optics, while consuming less valuable space and producing a more uniform illumination output. Moreover, by the characteristics of the integration technology, not only finger navigation but also fingerprint recognition operation is required in a small one-piece operation. Within the package, the present invention embodies multi-functional optical operation in a more economical and space-saving manner.

The arrangement of the microlens elements in the microlens array 121 and the light sensing elements in the light sensing unit 42 can be determined depending on specific operational requirements or other setting factors. For example, in one embodiment, each microlens element within the microlens array 121 can be associated with an optical diode of the light sensing unit 42 in a pair in a pair. Alternatively, each microlens element within microlens array 121 can correspondingly incorporate multiple optical diodes, and vice versa. In particular, the arrangement of the particular microlenses of the present invention allows each microlens within the microlens array 121 to be designed to cover a particular number of optical diodes, thereby reducing the complexity of the structural optical components while maintaining efficiency Light transmission and focusing capabilities. Furthermore, the position and clearance of the lens can be designed to reduce the overlap of the objects.

Referring to Fig. 1, additional light shielding members, such as glazing shield 2 and lower light shielding member 5, can be used to reduce the interference of possible optical crosstalk effects and improve the sensing performance of the finger sensing device of the present invention. In this embodiment, each of the upper and lower light shielding members 2, 5 is substantially flat, and each of the light shielding members has an aperture array formed on a flat surface thereof. The array of perforations is arranged to correspond to the configuration of the microlens array 121. In particular, the size of the perforations and the structural plan can determine the field of view (FOV) of the individual microlenses, and can further assist in reducing crosstalk of light. In order to achieve a better structural integration to mount the upper and lower light shielding members 2, 5, the integrated optical module 1 can be designed to include a concave structure in the imaging portion 12. For example, in the embodiment, the optical module 1 has a concave structure formed in the imaging portion 12, wherein the microlens array 121 is disposed on the concave junction. Within the structure. The concave structure is visible on the flat surface of the optical module 1 as a mounted mounting tray to hold the light shielding member. However, the use of light shielding members is optional, in particular the lower light shielding members 5 are optional; and the actual structure of the light shielding members should be based on a particular structural arrangement and/or other optional requirements. .

However, the above description is only a preferred embodiment of the present invention, and thus the scope of the present invention is not limited thereto, and the equivalent technical changes of the present specification and the contents of the drawings are all included in the present invention. Within the scope of the agreement, Chen Ming.

1‧‧‧Integrated optical module

11‧‧‧Lighting Department

111‧‧‧Light guide array

111a, 111b, 111c‧‧‧Light guides

12‧‧‧Image Department

121‧‧‧Microlens array

121a‧‧‧Recognition lens unit

121b‧‧‧Navigation lens unit

2‧‧‧Gloss Shield

3‧‧‧window module

4‧‧‧Electronic module

41‧‧‧Light source

41a, 41b, 41c‧‧‧Light source components

42‧‧‧Light sensing unit

43‧‧‧ shading structure

5‧‧‧Lighting shield

1 is an exploded perspective view of an optical finger sensing device having an integrated optical module according to the inventive concept.

2 is a side cross-sectional view of the optical finger sensing device of the present invention.

3 is a perspective view of an integrated optical module of the present invention.

4 is a schematic view of an illumination portion of an integrated optical module of the present invention.

Figure 5 is a schematic illustration of an imaging portion of an integrated optical module of the present invention.

Figure 6 is a schematic illustration of another illumination portion of the integrated optical module of the present invention.

1‧‧‧Integrated optical module

11‧‧‧Lighting Department

12‧‧‧Image Department

2‧‧‧Gloss Shield

3‧‧‧window module

4‧‧‧Electronic module

41‧‧‧Light source

42‧‧‧Light sensing unit

43‧‧‧ shading structure

5‧‧‧Lighting shield

Claims (15)

An integrated optical module is disposed between a window module having a touch surface and an electronic module having a light source and a light sensing unit, and includes: an illumination portion including a light guiding array for facing the window mold The group directs incident light from the light source at a predetermined angle of incidence; and an imaging portion includes a microlens array disposed thereon to direct reflected light from the window module toward the light sensing unit; The microlens array includes an elongated identification unit having a column axis substantially perpendicular to the light guiding array, and a navigation unit adjacent to the identification unit and juxtaposed with the column axis. The integrated optical module of claim 1, wherein the light guiding array comprises at least three light guiding members arranged adjacent to the imaging portion. The integrated optical module of claim 1, wherein the identification unit comprises a microlens array disposed in a single arrangement. The integrated optical module of claim 1, wherein the navigation unit comprises a single microlens. The integrated optical module of claim 4, wherein the navigation unit is disposed at a position near the center of the elongated identification unit. The integrated optical module of claim 1, wherein the integrated optical module is substantially a flat body, wherein the illumination portion and the image forming portion are integrally molded structures. The integrated optical module of claim 1, wherein the imaging portion comprises a shielding structure. The integrated optical module of claim 7, wherein the shielding structure comprises an anti-crosstalk layer. The integrated optical module of claim 1, wherein the image forming portion comprises at least one concave structure tray to incorporate a light shielding member. A finger scanning device includes: a window module having a touch surface for receiving a finger to be scanned thereon; and an electronic module including a light source and a light sensing unit correspondingly facing the window module And an integrated optical module disposed between the window module and the electronic module, the integrated optical module comprising: an illumination portion having a light guiding array for guiding the light source The light is aligned with the window module at a predetermined incident angle; and an image forming portion has a microlens array disposed thereon for reflecting light from the window module toward the light sensing unit; wherein the light The lens array includes: an elongated identification unit having a column axis substantially perpendicular to the light guiding array; and a navigation unit adjacent to the identification unit and juxtaposed with the column axis. The finger scanning device of claim 10, wherein the light guiding array comprises at least three light guiding members arranged adjacently to face the image forming portion. The finger scanning device of claim 10, wherein the identification unit comprises a microlens array disposed in a single arrangement. The finger scanning device of claim 10, wherein the navigation unit comprises a single microlens. The finger scanning device of claim 10, wherein the integrated optical module is substantially a flat body, wherein the illumination portion and the image forming portion are integrally molded molding structures. The finger scanning device of claim 10, further comprising a light shielding member disposed on a surface of the imaging portion of the integrated optical module and configured to substantially correspond to the microlens array.