WO2009096618A1

WO2009096618A1 - Optical navigation sensor device and optical module, a portable mouse using the same

Info

Publication number: WO2009096618A1
Application number: PCT/KR2008/000633
Authority: WO
Inventors: Il Sug Chung; Yong Tak Lee
Original assignee: Ytel Photonics Inc.
Priority date: 2008-02-01
Filing date: 2008-02-01
Publication date: 2009-08-06

Abstract

Provided is an optical navigation sensor device. A semiconductor light source is integrated along with a plurality of unit light detection arrays. When light emitted from the semiconductor light source is reflected by an external surface, the light detection arrays sense motion by detecting the reflected light. When a module is manufactured using the optical navigation sensor device, its entire size is significantly reduced, such that a lightweight, thin, and compact module can be manufactured. An inexpensive module can be manufactured by process simplification.

Description

OPTICAL NAVIGATION SENSOR DEVICE AND OPTICAL MODULE, A PORTABLE MOUSE USING THE SAME

Technical Field

[1] The present invention relates to an optical navigation sensor device, and more particularly, to an optical navigation sensor device available for optical navigation sensing in an optical mouse, etc. and an optical module and portable mouse using the same. Background Art

[2] In the early 1990', personal computer (PC) operating systems began changing from text-based Microsoft Disk Operating System (MS-DOS) to graphic-based Microsoft Windows. Accordingly, a mouse for moving a cursor on a screen became an essential input device of a desktop PC. Early mice were mechanical devices called ball mice. The ball mouse senses mechanical motion of a ball through a shaft encoder, converts the motion into an electrical signal and determines a cursor position. Over time, foreign material accumulates on the mechanical mouse and degrades its motion sensitivity.

[3] This disadvantage was overcome with the development by Agilent Technologies in

1999 of an optical mouse using a light-emitting diode (LED). According to the operation principle of the LED optical mouse, light emitted from an LED is reflected from a surface with a distribution that reflects the form and properties of the surface. A two-dimensional electrical image is generated by enabling the reflected light to form an image on an optical sensor. A cursor position is determined by analyzing a time- variant image and calculating a relative position variation and speed.

[4] However, there is a disadvantage in that the LED optical mouse's motion sensitivity differs according to surface state. Early LED optical mice normally operated only on a dedicated mouse pad with a grid. However, recent performance-improved models stably operate on most low-reflection surfaces except paper or smooth wood. A laser diode (LD) optical mouse addresses this problem.

[5] The LD optical mouse uses an LD instead of an LED as a light source. The LD was first developed by Agilent Technologies in 2004. Since light output from the LD is coherent, a speckle is formed without any image of the reflection surface when the light reflected from the surface arrives at the optical sensor. Since the speckle is caused by interference due to an optical path length difference from the surface to the optical sensor, it is not sensitive to a surface state. The optical path length difference occurs as long as the reflection surface is irregular within an error range of about a wavelength of a light source (~ 10^"7 m). Since the LD optical mouse provides 20 times higher sensitivity and lower power consumption than the LED optical mouse, it is appropriate for games or wireless operation. A conventional optical navigation sensor is disclosed in U.S. Patent Nos. 6,934,037 and 6,967,321.

[6] A conventional optical navigation sensor device will now be described. FIG. 1 is a block diagram of a conventional optical navigation sensor system.

[7] Referring to FIG. 1, light 32 emitted from an LD 30 becomes parallel light 26 by passing through a collimating lens 28. The parallel light 26 is radiated onto a surface 10 for observing motion. Light 24 reflected from the surface forms an image on an optical sensor 16 through an imaging lens 22. At this time, a speckle size of the image formed on the optical sensor is adjusted by controlling the size of an opening 18 formed in an aperture stop 20.

[8] For example, the optical sensor 16 includes N * N optical sensor pixels 16a. Light arriving at each pixel 16a is converted into an electrical signal in a voltage/current form. FIG. 2 shows a structure of N * N optical sensor pixels.

[9] For efficient fabrication and easy alignment in the conventional structure, the collimating lens 28, the imaging lens 22, and a waveguide connected thereto constitute one connection form. In actual implementation, such a basic structure may be modified in various forms, but the above-described components are usually included.

[10] On the other hand, since the LD 30 is usually packaged in a CAN form, optical components of the collimating lens 28, the optical waveguide (not shown), the imaging lens 22, etc. are separately manufactured to occupy separate spaces, the size of the entire optical mouse or module is about (16 mm (width) * 31 mm (length) * 20 mm (height)).

[11] For miniaturization and precision, the performance and size of the optical mouse structure should be improved. Specifically, in view current demand for an optical mouse separated from a main body of an electronic device and an optical navigation device embedded into the main body, miniaturization of the optical navigation device should be further enhanced. For example, portable electronic devices of a laptop computer, tablet PC, personal digital assistant (PDA), etc. include at least one navigation device. Disclosure of Invention Technical Problem

[12] The present invention has been made in view of the above problems, and an object of the present invention is to reduce the overall size of the optical navigation sensor device.

[13] Another object of the present invention is to provide a highly cost-effective optical navigation sensor device by manufacturing a light source and a light detector in one integrated device to reduce the number of components and simplify processing.

[14] Still another object of the present invention is to provide an optical navigation sensor device that can reduce an external lens.

[15] Yet another object of the present invention is to provide a portable mouse that can be used as an optical navigation device of another electronic device screen through a local-area wireless communication module (Bluetooth, ZigBee, or the like).

[16] Yet another object of the present invention is to manufacture a lightweight, thin, compact, and inexpensive portable mouse to be used as an optical navigation device of another electronic device screen. Technical Solution

[17] According to a first aspect of the present invention, as a technical solution for achieving the above objects, there is provided an optical navigation sensor device including: at least one semiconductor light source formed by providing a light-emitting region in one region of a substrate; and a light detection array integrated with the semiconductor light source on the same substrate and configured with a plurality of unit light detectors having light-receiving regions, wherein when light emitted from the semiconductor light source is reflected by an external surface, the light detection array senses motion by detecting the reflected light.

[18] The semiconductor light source may emit light to an upper portion with reference to the substrate by a top emission method, or may emit light to a backside of the substrate.

[19] Preferably, the optical navigation sensor device may further include: a microlens arranged on a light emission path of the semiconductor light source, wherein the microlens is integrated together with the substrate.

[20] Preferably, the semiconductor light source may include, in order from the substrate, a first distributed Bragg reflector, a light-emitting region, and a second distributed Bragg reflector. And, the light detectors may include, in order from the substrate, a first distributed Bragg reflector, a light-receiving region, and a second distributed Bragg reflector.

[21] Preferably, the semiconductor light source may be a vertical-cavity surface-emitting laser and the light detectors may be resonant-cavity enhanced photodiodes or metal- semiconductor- metal (MSM) photodiodes.

[22] According to a second aspect of the present invention, there is provided an optical navigation sensor device including: unit optical devices formed in an N x M matrix (where at least one of N and M is a natural number equal to or greater than 2), wherein at least one of the unit optical devices is a semiconductor light source having a light- emitting region, unit optical devices excluding the semiconductor light source are light detectors, and, when light emitted from the semiconductor light source is reflected by an external surface, the light detectors sense motion by detecting the reflected light.

[23] Preferably, the optical navigation sensor device may further include an external lens arranged on a light emission path of the semiconductor light source.

[24] According to a third aspect of the present invention, there is provided an optical module using an optical navigation sensor device including: an optical navigation sensor device having unit optical devices formed in an N x M matrix (where at least one of N and M is a natural number equal to or greater than 2), wherein at least one of the unit optical devices is a semiconductor light source having a light-emitting region, unit optical devices excluding the semiconductor light source are light detectors, and, when light emitted from the semiconductor light source is reflected by an external surface, the light detectors sense motion by detecting the reflected light; and a printed circuit board, connected to the optical navigation sensor device, that applies a voltage to the optical navigation sensor device and has circuits to detect various information.

[25] The optical navigation sensor device and the printed circuit board may be connected by wire bonding or flip-chip bonding.

[26] Preferably, the optical module using the optical navigation sensor device may further include: an external lens arranged on an optical path between the optical navigation sensor device and an external surface.

[27] The optical module manufactured by the above-described method may be used in an optical mouse or an optical mouse embedded into a main body of an electronic device.

[28] According to a fourth aspect of the present invention, there is provided a portable mouse including: an optical navigation sensor comprising a light source that generates light and a light detector that detects reflected light generated in the light source; a movement determiner that receives an electrical signal output from the optical navigation sensor and calculates a distance and direction according to movement; a key input unit that selects an item based on a pointer position; and a controller that receives signals from the movement determiner and the key input unit and controls data based on the movement distance and direction and a key input to be sent to an external electronic device using wireless communication, wherein the portable mouse is mounted in an electronic device in which local-area wireless communication is possible, and the optical navigation sensor has unit optical devices formed in an N x M matrix on a substrate, wherein at least one of the unit optical devices is a semiconductor light source having a light-emitting region and all other unit optical devices are light detectors.

[29] Preferably, the optical navigation sensor may be configured by integrating the light source and the light detector on the same substrate.

[30] Preferably, Bluetooth may be used for the local-area wireless communication. [31] Preferably, ZigBee may be used for the local-area wireless communication.

[32] Preferably, the optical navigation sensor may have a structure for sensing light reflected by a human finger when light is emitted from the light source, or a structure for sensing light reflected from an external bottom surface.

[33] According to a fifth aspect of the present invention, there is provided a portable mouse including: an optical navigation sensor comprising a light source that generates light and a light detector that detects reflected light generated in the light source; a movement determiner that receives an electrical signal output from the optical navigation sensor and calculates a distance and direction according to movement; a key input unit that selects an item based on a pointer position; and a controller that receives signals from the movement determiner and the key input unit and controls data based on the movement distance and direction and a key input to be sent to an external electronic device using wireless communication, wherein the portable mouse is mounted in an electronic device in which local-area wireless communication is possible, the optical navigation sensor has the light source arranged at its center and the light detector is separated into a plurality of independent light-detecting regions in a radial structure to detect reflected light from the light source, and the movement determiner senses continuous movement in a light detection direction when light is detected in the independent light-detecting regions.

Advantageous Effects

[34] The present invention has the following advantageous effects:

[35] (1) When an optical navigation sensor device of the present invention is used, the overall size of the optical module is significantly reduced, thereby enabling manufacture of a lightweight, thin, compact, and inexpensive optical module.

[36] (2) Optical navigation of the present invention has greater accuracy than conventional optical navigation. Accordingly, when the optical navigation of the present invention is applied to an optical mouse, the optical mouse can have greater accuracy than a conventional optical mouse and the number of components such as an optical waveguide, an external lens, etc. can be reduced.

[37] (3) The optical navigation sensor device of the present invention can be used as an optical screen navigation device of another electronic device (desktop computer, notebook computer, PDA, portable multimedia player (PMP), portable multimedia player computer (PMPC), ultra multimedia personal computer (UMPC), or the like) through a portable electronic device (mobile phone, MP3 player, remote control, or the like) having a local-area wireless communication (Bluetooth or ZigBee) module, without purchasing an additional mouse.

[38] (4) When a light source is mounted in a light detector (charge-coupled device (CCD)) of an existing mobile phone, an additional light detector is not needed and an existing mobile phone structure does not require major modification, such that a portable mouse can be inexpensively manufactured. [39] (5) When a monolithically integrated chip is used for an optical navigation sensor, a laser mouse function can be added without increasing the size of a portable product such as a mobile phone or the like in which the optical navigation sensor is mounted. [40] (6) A portable micro laser mouse makes a more convenient optical screen navigation device than existing navigation buttons and touch screen systems installed in electronic devices.

Brief Description of Drawings

[41] FIG. 1 is a block diagram of a conventional optical navigation sensor system.

[42] FIG. 2 shows an N * N optical sensor pixel structure.

[43] FIG. 3 shows a plan view and a cross-sectional view of a part of an optical navigation sensor device according to a first exemplary embodiment of the present invention. [44] FIG. 4 is a schematic diagram of a structure of an optical navigation sensor device

960 manufactured according to the first exemplary embodiment. [45] FIGS. 5 and 6 show an optical navigation sensor system constituted using the optical navigation sensor device 960 of FIG. 4. [46] FIG. 7 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to a second exemplary embodiment of the present invention. [47] FIGS. 8 and 9 are conceptual diagrams illustrating an example of using a microlens and an external lens according to the second exemplary embodiment. [48] FIG. 10 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to a third exemplary embodiment of the present invention. [49] FIG. 11 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to a fourth exemplary embodiment of the present invention. [50] FIGS. 12 to 15 are cross-sectional views showing optical modules actually manufactured using the optical navigation sensor devices according to the first to fourth exemplary embodiments. [51] FIG. 16 is a conceptual view illustrating a state in which the optical navigation sensor devices of these exemplary embodiments are actually embedded into an electronic device and used. [52] FIG. 17 is a block diagram illustrating a portable mouse using a local-area wireless communication module according to a fifth exemplary embodiment of the present invention. [53] FIG. 18 shows an example of implementing an optical navigation sensor 1100 according to the fifth exemplary embodiment of the present invention.

[54] FIG. 19 shows a specific example of an optical navigation sensor shown in FIG. 17.

[55] FIG. 20 shows another example of the optical navigation sensor shown in FIG. 17.

[56] FIG. 21 shows an example of implementing a light source and a light detector shown in FIG. 17.

[57] FIG. 22 shows a mouse of the present invention mounted in a mobile phone, FIG.

22(a) shows a front side, and FIG. 22(b) shows a backside.

[58] FIG. 23 shows an example of using a portable mouse according to the present invention. Mode for the Invention

[59] Hereinafter, preferred exemplary embodiments of the present invention will be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully enable those skilled in the art to embody and practice the present invention.

[60] (First Exemplary Embodiment)

[61] Now, a first exemplary embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 3 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to the first exemplary embodiment of the present invention. The cross-sectional view is taken along line A-B of the plan view.

[62] Referring to FIG. 3, the optical navigation sensor device includes a light source C and a light detector D which are integrated and manufactured together on a substrate 100.

[63] The light source C and the light detector D are formed in separate regions on the semiconductor substrate 100 and include a light-emitting region 106 and a light- receiving region 206, respectively. One semiconductor light source and one light detector respectively formed in the light source C and the light detector D are shown in FIG. 3. In practice, at least one semiconductor light source and a plurality of light detectors may be configured (see FIG. 4).

[64] In the structure of FIG. 3, when light emitted from the semiconductor light source is reflected by an external surface, the light detector detects the reflected light. Accordingly, when this structure is applied to the optical navigation sensor device, motion can be sensed. This will be described in detail later.

[65] The semiconductor light source according to the first exemplary embodiment may emit light to an upper or lower portion of the substrate. [66] An example of a detailed configuration of a part of the optical navigation sensor device according to the first exemplary embodiment of the present invention will now be described.

[67] Referring to FIG. 3, the optical navigation sensor device includes a first distributed

Bragg reflector 120, second distributed Bragg reflectors 103 and 203, n-type ohmic contact layers 104 and 204, p-type ohmic contact layers 108 and 208, light-emitting layers 106 and 206, n-type electrodes 101 and 201, and p-type electrodes 102 and 202 on an n-type semiconductor substrate 100. A polymer layer 300 is formed by coating a resin such as polyimide or the like to expose a light-emitting opening and a light- receiving opening and cover the entire structure of the optical navigation sensor device.

[68] It is preferable to use an n-type semiconductor substrate as the substrate 100. For example, the substrate 100 can be a compound semiconductor of a GaAs or InP series, but various types of substrates in which a light-emitting region can be grown are possible without any special limitation. If needed, a glass substrate, a sapphire substrate, etc. may be included.

[69] The light-emitting region 106 is a region where light is emitted when electrons and holes supplied from negative and positive electrodes are recombined. In the light- emitting region 106, a type of bulk, a semiconductor quantum well, a quantum point, etc. are possible.

[70] The first and second distributed Bragg reflectors 120, 103, and 203 can be configured in a structure in which a material layer of a high refractive index and a material of a low refractive index have predetermined thicknesses and are stacked in alternating fashion.

[71] Light emitted from the light-emitting region 106 can go to an upper or lower portion by adjusting reflection characteristics of the first distributed Bragg reflector 120 and the second distributed Bragg reflectors 103 and 203. The reflectance of the first and second distributed Bragg reflectors 103 and 203 and the amount of light emitted in an up or down direction can be adjusted by increasing/decreasing the number of layers.

[72] An example of an actual manufacturing process of the first exemplary embodiment will be described. First, a structure is formed in which the first distributed Bragg reflector 120, the n-type ohmic contact layers 104 and 204, the p-type ohmic contact layers 108 and 208, the light-emitting layers 106 and 206, and the second distributed Bragg reflectors 103 and 203 are sequentially stacked on the n-type semiconductor substrate 100. Then, the second distributed Bragg reflectors 103 and 203 are selectively etched from the upper portion, the p-type ohmic contact layers 108 and 208 and the light-emitting layers 106 and 206 are selectively etched, and the n-type ohmic contact layers 104 and 204 and the first distributed Bragg reflector are selectively etched.

[73] Then, the polymer layer 300 is formed by coating a resin such as polyimide or the like to expose the light-emitting opening and the light-receiving opening and cover the entire structure of the optical navigation sensor device. The n-type electrodes 101 and 201 and the p-type electrodes 102 and 202 are formed by selectively performing etch, metal deposition, and metal patterning processes on the polymer layer 300.

[74] FIG. 4 is a schematic diagram of a structure of an optical navigation sensor device

960 manufactured according to the first exemplary embodiment. The entire optical navigation sensor device 960 is configured by including a part of the optical navigation sensor device of FIG. 3.

[75] Referring to FIG. 4, unit optical devices 901 and 961 are formed in an N x M matrix on the substrate. At least one of the unit optical devices includes the semiconductor light source having a light-emitting region. Except for the semiconductor light source, the other optical devices are the light detectors 961. In this regard, FIG. 4 shows the optical navigation sensor device including the unit optical devices in a 7 x 7 matrix, and shows an example of one semiconductor light source. Here, at least one of N and M is a natural number equal to or greater than 2.

[76] On the other hand, when light emitted from the semiconductor light source 901 is reflected by an external surface, the light detectors 961 sense motion by detecting the reflected light.

[77] FIG. 5 shows an optical navigation sensor system constituted using the optical navigation sensor device 960 of FIG. 4.

[78] Referring to FIG. 5, light 970 emitted from the semiconductor light source (denoted by reference numeral 901 of FIG. 4) of the optical navigation sensor device 960 according to the first exemplary embodiment becomes substantially parallel light by passing through a lens 950. Light 930 is radiated onto an external surface 900 for observing motion, and light 940 reflected from the surface forms an image on the light detectors (denoted by reference numeral 961 of FIG. 4) of the optical navigation sensor device 960 through the lens 950.

[79] In the optical navigation sensor device 960, pixels of the semiconductor light source

901 may be located at a center as shown in FIG. 4, or an edge (see FIG. 6), and may be placed at arbitrary positions according to a motion-sensing algorithm.

[80] The optical navigation sensor device according to the first exemplary embodiment is applicable to all types of semiconductor light sources and light detectors capable of being integrated. Preferably, when a vertical-cavity surface-emitting laser is used as the semiconductor light source, the vertical-cavity surface-emitting laser is suitable for low-power applications. On the other hand, it is preferable that the light detector capable of being easily, monolithically integrated with the vertical-cavity surface- emitting laser is a resonant-cavity enhanced photodiode.

[81] Since the resonant-cavity enhanced photodiode is similar to a growth structure of stacked layers of the vertical-cavity surface-emitting laser, its integration is facilitated. Since only resonant wavelengths are detected, the effect of noise is small. Preferably, a resonant wavelength of the resonant-cavity enhanced photodiode is the same as an output wavelength of the vertical-cavity surface-emitting laser.

[82] When the optical navigation sensor device of the first exemplary embodiment is used, the overall size of the optical module is significantly reduced, thereby manufacturing a lightweight, thin, and compact optical module. An optical module can be inexpensively manufactured by process simplification. Optical navigation of the present invention has greater accuracy than conventional optical navigation, so when the optical navigation of the present invention is applied to an optical mouse, the optical mouse has greater accuracy than a conventional optical mouse. Since light emitted by the light source and reflected light propagate along the same optical axis, an additional optical waveguide is unnecessary.

[83] (Second Exemplary Embodiment)

[84] Now, a second exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[85] FIG. 7 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to the second exemplary embodiment of the present invention. The cross-sectional view is taken along line A-B of the plan view.

[86] Referring to FIG. 7, the optical navigation sensor device includes a first distributed

[87] For convenience, only differences from the first exemplary embodiment will be described. One of the main differences from the first exemplary embodiment is a structure in which a microlens is integrated with a semiconductor light source in the second exemplary embodiment. In particular, a microlens 105 is formed on an upper portion of the second distributed Bragg reflector mirrors 103 in the second exemplary embodiment, but on a lower portion of the semiconductor substrate 100 in a third exemplary embodiment.

[88] A process for selectively integrating the microlens 105 with the semiconductor light source can be easily achieved in the fabrication step. A fabrication method is not specially limited and various methods are possible. For example, fabrication methods disclosed in Korean Patent Publication No. 2006-43912 and Korean Patent Application No. 2005-114145 filed by the present inventors are available.

[89] An example of manufacturing the microlens 105 will be described with reference to

Korean Patent Publication No. 2006-43912. The first distributed Bragg reflector 120, the n-type ohmic contact layers 104 and 204, the p-type ohmic contact layers 108 and 208, the light-emitting layers 106 and 206, and the second distributed Bragg reflectors 103 and 203 are sequentially stacked on the n-type semiconductor substrate 100. Then, a compound semiconductor oxidation layer 109 is formed by gradually increasing an aluminum ratio to manufacture the microlens. Then, a portion 107 whose aluminum ratio is high by oxidation at a high temperature acts as an oxide material having a low refractive index, and a portion 105 whose aluminum ratio is low remains in an original compound semiconductor state and acts as a lens having a high refractive index. A focal length of the lens is varied by adjusting oxidation time, temperature, oxidation layer growth conditions, etc.

[90] An optical navigation sensor device manufactured by integrating a microlens structure with a semiconductor light source is manufactured in an array form as shown in FIG. 4 or 6 of the first exemplary embodiment. An optical navigation sensor system is configured with the same structure as shown in FIG. 5 using the optical navigation sensor device of the second exemplary embodiment.

[91] According to the second exemplary embodiment, light emitted from the light- emitting region 106 of the semiconductor light source passes through the integrated microlens 105 and an external lens 950 when going through an opening and becomes substantially parallel light. Light 930 is radiated onto an external surface 900 for observing motion. Reflected light 940 from the surface forms an image on the optical navigation sensor device 960 after passing through the lens 950. A speckle size can be adjusted through a size of an opening 911 formed in an aperture stop 910.

[92] FIGS. 8 and 9 are conceptual diagrams illustrating an example of using a microlens and an external lens according to the second exemplary embodiment. FIG. 8 shows a process in which light 909 emitted from a semiconductor light source 901 goes through a microlens 921 and an external lens 950, and FIG. 9 shows a process in which light reflected by an external surface goes through the external lens 950 and the microlens 921.

[93] First, referring to FIG. 8, both the microlens 921 and the external lens (imaging lens)

950 generate the parallel light 930 and the external lens 950 forms an image. In this case, assuming that the two lenses are thin, a focal length/ of the microlens 921 and a focal length/ of the external lens 950 are defined by the following equations: [94] 1 1 1

and

[95] J _{γ γ}

4 ^∞ f, f.

[96] where <i denotes a distance between the external surface (reflection surface) and the external lens 950 and d denotes a distance between the external lens 950 and the i optical navigation sensor device 961. A precise lens design can be determined by numerical calculations.

[97] On the other hand, the number of external lenses 950 can be reduced by using the microlens 921 in the second exemplary embodiment. For example, the number of external lenses in the second exemplary embodiment is reduced to one compared to two external lenses in the prior art of FIG. 1.

[98] (Third Exemplary Embodiment)

[99] Now, a third exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[100] FIG. 10 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to the third exemplary embodiment of the present invention. The cross-sectional view is taken along line A-B of the plan view.

[101] Referring to FIG. 10, the optical navigation sensor device includes a first distributed Bragg reflector 120, second distributed Bragg reflectors 103 and 203, n-type ohmic contact layers 104 and 204, p-type ohmic contact layers 108 and 208, light-emitting layers 106 and 206, n-type electrodes 101 and 201, and p-type electrodes 102 and 202 on an n-type semiconductor substrate 100. A polymer layer 300 is formed by coating a resin such as polyimide or the like to cover the entire structure of the optical navigation sensor device and expose a light-emitting opening and a light-receiving opening.

[102] For convenience, differences from the first exemplary embodiment will be described. One of the main differences from the first exemplary embodiment is a structure in which a microlens is integrated with a semiconductor light source in the third exemplary embodiment. In particular, a microlens 105 is formed on an upper portion of the second distributed Bragg reflector mirrors 103 in the second exemplary embodiment, but a microlens 110 is formed on a lower portion of the semiconductor substrate 100 in the third exemplary embodiment.

[103] While light is emitted to an upper portion of the substrate in the first and second exemplary embodiments, light is emitted to a lower surface by passing through the substrate in the third exemplary embodiment. To emit light to the lower surface, the third exemplary embodiment has a different structure from the first and second exemplary embodiments. For example, the first distributed Bragg reflector 120 and the second distributed Bragg reflectors 103 and 203 adjust reflection characteristics such that light emitted from the light-emitting region 106 can go to the lower portion.

[104] Among methods for forming a microlens on a lower surface of a substrate, a reflow method will be briefly described. First, a cylindrical photoresist pattern of a desired size is formed on the lower portion of the substrate 100 using photolithography. In heat and reflow processes, the cylindrical photoresist is formed into a lens shape having a thick center and a thin edge by surface tension. When dry etching is performed using the lens-shaped photoresist as a mask, the microlens 110 is formed on the lower portion of the substrate 100.

[105] According to the third exemplary embodiment, light emitted from the light-emitting region 106 of the semiconductor light source passes through the integrated microlens 110 when going through an opening, thereby reducing beam divergence. Since the only difference between the second and third exemplary embodiments is the direction in which emitted light propagates with respect to the substrate, further detailed description of the third exemplary embodiment will be omitted.

[106] (Fourth Exemplary Embodiment)

[107] Now, a fourth exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[108] FIG. 11 is a plan view and a cross-sectional view of a part of an optical navigation sensor device according to the fourth exemplary embodiment of the present invention. The cross-sectional view is taken along line A-B of the plan view.

[109] According to the fourth exemplary embodiment, the optical navigation sensor device includes a metal-semiconductor-metal (MSM) light detector as well as the resonant- cavity enhanced photodiode shown in the first to third exemplary embodiments as a light detector.

[110] Differences from the first exemplary embodiment will be described. In the fourth exemplary embodiment, a light-absorbing layer 304 and Schottky metal layers 301 and 302 are formed on an upper portion of a second distributed Bragg reflector mirror 210 and function as a light detector.

[I l l] Light detection efficiency can be enhanced by widening a light-detecting region in the MSM light detector structure. When the light detection efficiency is good, sensing sensitivity can be improved. On the other hand, a light detector with a Schottky structure can maximize light detection speed by properly adjusting an RC time constant t determined by electrostatic capacitance and resistance, and a required transit time t , when electrons or holes generated by a light signal go through a light- absorbing layer of the light detector. In this regard, it is better to increase light detection efficiency than to increase speed to several GHz as in a communication device for motion sensing.

[112] On the other hand, it is preferable to configure the optical navigation sensor device according to the fourth exemplary embodiment with a semiconductor light source for emitting light to the upper portion of the substrate.

[113] (Optical Module Using Optical Navigation Sensor Device)

[114] FIGS. 12 to 15 are cross-sectional views showing optical modules actually manufactured using the optical navigation sensor devices according to the first to fourth exemplary embodiments. Specifically, FIGS. 12 and 13 show an optical module manufactured by a wire bonding method, and FIGS. 14 and 15 show an optical module manufactured by flip-chip bonding.

[115] First, the wire bonding method will be described with reference to FIGS. 12 and 13. An optical navigation sensor device 500 is manufactured with unit optical devices 510 and 520 formed in an N x M matrix on a substrate, wirings for applying a voltage/ current to the unit optical devices, and connectors 508. The optical navigation sensor device 500 is housed in an upper portion of a predetermined region of a printed circuit board 600. The wirings for applying the voltage to the unit optical devices are connected to each other by the wire bonding method.

[116] FIG. 12 shows a state in which the unit optical device of a semiconductor light source is provided at the center and the unit optical devices of light detectors are provided around the semiconductor light source.

[117] The printed circuit board 600 includes various circuits for applying a voltage to the optical navigation sensor device 500. Since those skilled in the art can configure the above-described structure by a well-known method, its detailed description is omitted.

[118] On the other hand, since the wire boding method has a structure in which the optical navigation sensor device 500 is housed in an upper portion of the printed circuit board 600, it is preferable to apply the semiconductor light source provided in the optical navigation sensor device 500 to the first, second, and fourth exemplary embodiments using a method for emitting light to the upper portion of the substrate.

[119] Next, a flip-chip bonding method will be described with reference to FIGS. 14 and 15. An optical navigation sensor device 700 is manufactured by unit optical devices 710 and 720 formed in an N x M matrix on a substrate, wirings for applying a voltage/ current to the unit optical devices, and connectors 708. The optical navigation sensor device 700 is connected to the printed circuit board 800 having the wirings and the terminals 708 by the flip-chip bonding method. In this case, the connection terminals 708 of the optical navigation sensor device 700 are connected to terminals 808 of the printed circuit board 800 by metal balls (not shown). In this regard, a surface in which the terminals are formed on the upper portion of the substrate of the optical navigation sensor device 700 in the flip-chip bonding method is connected to a surface in which the terminals are formed on the printed circuit board 800 such that the surfaces face each other. Accordingly, the flip-chip bonding method is more suitable for a backside light-emitting structure in which light emitted from the semiconductor light source goes to a lower portion of the substrate. An optical navigation sensor device capable of backside light emission will be described with reference to the first and third exemplary embodiments.

[120] Upon flip-chip bonding, metal balls (not shown) are formed of metals such as Au, Au-Sn, etc., with a diameter size of about 20 ~ 30 mm, such that the terminals of the unit devices can be connected to the terminals of the printed circuit board.

[121] FIG. 16 is a conceptual view illustrating a state in which the optical navigation sensor devices of these exemplary embodiments are actually embedded into an electronic device and used.

[122] FIG. 16 shows a state in which the motion of a human hand 100 is sensed by an optical navigation sensor device 960 embedded into an electronic device.

[123] When the optical navigation sensor device according to the first to fourth exemplary embodiments can be used for a general optical mouse, a subminiature optical mouse having excellent sensing efficiency can be implemented. In particular, the optical navigation sensor device can be useful to actually implement an optical mouse embedded into a main body of an electronic device.

[124] In general, an embedded optical navigation device is used in a compact electronic device in which portability is enhanced. For example, at present, a touch pad in a laptop computer and a touch screen in a tablet PC or PDA are widely used for the optical navigation device. When the optical navigation sensor device of the present invention is used, an optical navigation function having excellent sensing efficiency can be effectively implemented in a subminiature size. The optical navigation sensor device can be used instead of a conventional optical mouse module using an LD.

[125] (Fifth Exemplary Embodiment)

[126] Now, a fifth exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[127] FIG. 17 is a block diagram illustrating a portable mouse using a local-area wireless communication module according to the fifth exemplary embodiment of the present invention.

[128] A portable mouse 1110 includes an optical navigation sensor 1100, a movement determiner 1101, a key input unit 1102, a controller 1103, and a local-area wireless communicator 1104. The portable mouse communicates with a peripheral electronic device 1120 using local- area wireless communication.

[129] The optical navigation sensor 1100 includes a light source 1100a and a light detector 1100b. When light emitted from the light source 1100a is reflected from a human finger or an external bottom, the light detector 1100b detects the reflected light. According to light intensity, the light detected by the light detector 1100b is converted into an electrical signal of a current/voltage and the electrical signal is output. Signal output from the optical navigation sensor 1100 is input to the movement determiner 1101 and a distance and direction according to movement is calculated. A digital signal processor (DPS) chip, etc. can be used for the movement determiner.

[130] The optical navigation sensor 1100 has a structure in which the light source 1100a and the light detector 1100b may be separated from each other or integrated together on the same substrate. It is preferable to provide a lightweight, thin, and compact structure manufactured by integrating the light source 1100a and the light detector 1100b on the same substrate. This structure will be described in detail later.

[131] On the other hand, in the light source 1100a of the optical navigation sensor 1100, (a) a method for sensing the motion of a human finger by means of emitted light uses a structure in which a person does not take the optical navigation sensor 1100 by the hand as in a touch pad of a notebook computer, and a method for sensing the motion of an external bottom surface by means of light emitted from the light source 1100a uses a structure in which a person directly takes and moves the optical navigation sensor 1100 by hand.

[132] According to the fifth exemplary embodiment, the above-described two methods are possible. When the high-integration optical navigation sensor 1100 is used, it is preferable to adopt method (b). When method (a) is adopted, for example, the light source 1100a may be arranged at the center and the light detector 1100b may be radially arranged in four (up, down, left, and right) directions around the light source 1100a. At this time, the light detector 1100b may include at least four independent light detectors 1100b, or may be integrated with the light source 1100a on the same substrate such that unit cells in the above-described four (up, down, left, and right) directions can detect light. The latter case can be easily realized by simply modifying the controller 1103. FIG. 18 shows an example of implementing the optical navigation sensor 1100 according to the fifth exemplary embodiment of the present invention.

[133] Referring to FIG. 18, this structure will be described in detail. For example, when desiring to continuously move a cursor in the right direction using a portable mouse, a user should continuously move a finger to the right such that the optical navigation sensor 1100 can sense it. If the user desires to continuously move the cursor to the right using the portable mouse upon light detection by separating four unit light- detecting regions, a right light-detecting region 1173 of the four unit light-detecting regions 1176 can continuously sense a finger position even when the user s finger stops on the right portion 1173 of an optical navigation sensing region. This method is more effective for manufacturing small sized systems by integrating the light detector 1100b and the light source 1100a on the same substrate. To implement this method, the configuration of the controller 1103 may be different. For example, in a structure in which the user should move the finger to the right in order to continuously move the cursor to the right using the portable mouse such that the optical navigation sensor 1100 can sense it, the controller 1103 has a structure for sensing the motion. Even when the user s finger stops on the right portion of the optical navigation-sensing region in order to continuously move the cursor to the right, a structure in which the user continuously moves the cursor to the right is a structure in which the controller 1103 senses a motion direction using an amount of light detected in the independent light-detecting regions.

[134] The key input unit 1102 plays a role in setting a user-desired function and performing an operation. That is, when a position of a mouse pointer is determined, an item corresponding to the position can be selected. The key input unit 1102 corresponds to a left button, a right button, and a wheel button of a general mouse.

[135] The controller 1103 receives signals from the movement determiner 1101 and the key input unit 1102, and plays a role in sending a corresponding coordinate value to another electronic device through a local-area wireless communicator by detecting a distance and direction according to movement and a button input. An electronic device 1120 has a local-area wireless communicator 1121. A mouse pointer of the electronic device 1120 moves according to a value received from a portable mouse 1110.

[136] A local-area wireless communicator 1104 can be configured with a baseband processor (not shown), an RF transceiver (not shown), and an antenna (not shown). The RF transceiver receives a signal from the baseband processor and converts the received signal into a signal suitable for transmission. This signal is sent through the antenna. A local-area wireless communicator 1121 of an electronic device 1120 includes similar components to receive a signal from the local-area wireless communicator 1104 of the portable mouse such that the electronic device detects mouse movement. Bluetooth, ZigBee, etc. can be used for local-area wireless communication.

[137] Furthermore, the portable mouse can have a memory (not shown) and a display (not shown). The memory temporarily stores required data and processed data by performing a buffer function. The display is a user interface device for allowing the user to view an overall state of the portable mouse, user input information, etc. The display is conventionally implemented with a liquid crystal display (LCD).

[138] FIG. 19 shows a specific example of an optical navigation sensor shown in FIG. 17.

[139] Referring to FIG. 19, a light source 1200a and a light detector 1200b are configured in one integrated device. Light generated from the light source 1200a becomes parallel light 1202 by passing through a lens. The light detector 1200b detects light reflected from a surface 1203 in a speckle pattern and converts the detected light into an electrical signal in current/voltage form according to light intensity. The movement determiner shown in FIG. 17 determines a distance and direction based on this electrical signal and the determined values are sent to the electronic device through the local- area wireless communication module.

[140] The light source 1200a and the light detector 1200b can be divided and included in a light-emitting region and a light-receiving region on the same semiconductor substrate. This structure has been described with reference to FIG. 5. Its details are disclosed in Korean Patent No. 2006-89048 filed on September 14, 2006 by the present applicant, the entire disclosure of which is incorporated in this application.

[141] FIG. 20 shows another example of the optical navigation sensor shown in FIG. 17.

[142] Referring to FIG. 20, in the case of a mobile phone equipped with a camera, a CCD is provided as a light detector within a camera lens. A mouse can be used by mounting a light source in the light detector of the mobile phone camera. Referring to FIG. 20, light generated from a light source 1301 mounted in the mobile phone camera becomes parallel light 1303 by passing through a lens 1302. Light reflected from a surface 1304 is detected by the light detector 1300. As described with reference to FIG. 17, a distance and direction are determined by comparing time-variant image variations in images detected by the light detector and the determined values are sent to the controller.

[143] FIG. 21 shows an example of implementing a light source and a light detector shown in FIG. 17.

[144] Referring to FIG. 21, unit optical devices 1401 and 1402 formed in an N x M matrix on a substrate are included and configured. At least one of the unit optical devices is the semiconductor light source 1401 having a light-emitting region, and the other unit optical devices are the light detectors 1402. In this regard, FIG. 21 shows an example of unit optical devices in a 7 x 7 matrix and one semiconductor light source. Here, at least one of N and M is a natural number equal to or greater than 2. When light emitted from the semiconductor light source 1401 is reflected by an external surface, the light detectors 1402 sense motion by detecting the reflected light.

[145] FIG. 22 shows a mouse of the present invention mounted in a mobile phone, FIG. 22(a) shows a front side, and FIG. 22(b) shows a backside.

[146] Referring to FIG. 22(a), reference numeral 1500 denotes a left button of the mouse, reference numeral 1501 denotes a right button of the mouse, and reference numeral 1502 denotes a wheel. Reference numeral 1503 denotes a liquid crystal display screen. That is, the left and right buttons of the mouse can be implemented using up and down keys arranged on a side of a conventional mobile phone. According to an exemplary embodiment, reference numeral 1501 may denote the left button of the mouse and reference numeral 1500 may denote the right button of the mouse.

[147] Referring to FIG. 22(b), reference numeral 1504 denotes the optical navigation sensor shown in FIG. 17. Since the optical navigation sensor is configured in one chip as an integrated device, it can be easily mounted in compact communication devices such as a mobile phone, etc. Light emitted from the light source of the optical navigation sensor is reflected from a surface of an object and detected in the light detector.

[148] FIG. 23 shows an example of using a portable mouse according to the present invention.

[149] Referring to FIG. 23, a mobile phone 1600 equipped with a portable mouse chip according to the present invention can move a mouse pointer 1602 of a screen of a PDA 1601 using local-area wireless communication. To use the mobile phone as the mouse, a change to a mouse mode can be made by pressing a specific key in the mobile phone. Then, light is emitted from a light source. A light detector detects an amount of light reflected from the surface and provides a detection result to a movement determiner. The movement determiner determines a distance and direction and sends calculated values to a controller. The controller sends the values from the movement determiner and a key input value to the PDA through a local-area wireless communication module.

[150] The portable mouse according to the present invention can be mounted in any electronic device having the local-area wireless communication module as well as the mobile phone. For example, the portable mouse can be mounted in an MP3 player, a remote controller, etc. Of course, an electronic device communicating with the portable mouse can be a computer, PDA, PMP, PMPC, UMPC, etc.

[151] Although exemplary embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the scope of the present invention. Therefore, the present invention is not limited to the above- described embodiments, but is defined by the following claims, along with their full scope of equivalents.

Claims

[1] An optical navigation sensor device comprising: at least one semiconductor light source formed by providing a light-emitting region in one region of a substrate; and a light detection array integrated with the semiconductor light source on the same substrate and configured with a plurality of unit light detectors having light- receiving regions, wherein when light emitted from the semiconductor light source is reflected by an external surface, the light detection array senses motion by detecting the reflected light.

[2] The optical navigation sensor device of claim 1, wherein the semiconductor light source emits light to an upper portion with reference to the substrate by a top emission method.

[3] The optical navigation sensor device of claim 1, wherein the semiconductor light source emits light to a backside of the substrate.

[4] The optical navigation sensor device of claim 1, further comprising: a microlens arranged on a light emission path of the semiconductor light source, wherein the microlens is integrated together with the substrate.

[5] The optical navigation sensor device of claim 1, wherein the semiconductor light source comprises, in order from the substrate, a first distributed Bragg reflector, a light-emitting region, and a second distributed Bragg reflector, and the light detectors comprise, in order from the substrate, a first distributed Bragg reflector, a light-receiving region, and a second distributed Bragg reflector.

[6] The optical navigation sensor device of claim 5, wherein a microlens is further integrated on an upper portion of the second distributed Bragg reflector of the semiconductor light source.

[7] The optical navigation sensor device of claim 5, wherein a microlens is further integrated on a lower portion of the substrate in a region where the semiconductor light source is formed.

[8] The optical navigation sensor device of claim 1, wherein the semiconductor light source is a vertical-cavity surface-emitting laser (VCSEL) and the light detectors are resonant-cavity enhanced photodiodes.

[9] The optical navigation sensor device of claim 1, wherein the semiconductor light source is a VCSEL and the light detectors are metal-semiconductor-metal (MSM) photodiodes.

[10] An optical navigation sensor device comprising: unit optical devices formed in an N x M matrix (where at least one of N and M is a natural number equal to or greater than 2), wherein at least one of the unit optical devices is a semiconductor light source having a light-emitting region and all other unit optical devices are light detectors, and when light emitted from the semiconductor light source is reflected by an external surface, the light detectors sense motion by detecting the reflected light.

[11] The optical navigation sensor device of claim 10, further comprising: a microlens arranged on a light emission path of the semiconductor light source, wherein the microlens is integrated together with the substrate.

[12] The optical navigation sensor device of claim 10, wherein the semiconductor light source emits light to an upper portion with reference to the substrate by a top emission method, or emits light to a backside of the substrate.

[13] The optical navigation sensor device of claim 10, wherein the semiconductor light source is a VCSEL and the light detectors are resonant-cavity enhanced photodiodes or MSM photodiodes.

[14] The optical navigation sensor device of claim 10, further comprising: an external lens arranged on a light emission path of the semiconductor light source.

[15] An optical module using an optical navigation sensor device, comprising: an optical navigation sensor device having unit optical devices formed in an N x M matrix (where at least one of N and M is a natural number equal to or greater than 2), wherein at least one of the unit optical devices is a semiconductor light source having a light-emitting region, unit optical devices excluding the semiconductor light source are light detectors, and, when light emitted from the semiconductor light source is reflected by an external surface, the light detectors sense motion by detecting the reflected light; and a printed circuit board, connected to the optical navigation sensor device, that applies a voltage to the optical navigation sensor device and has circuits to detect various information.

[16] The optical module using the optical navigation sensor device of claim 15, wherein the optical navigation sensor device and the printed circuit board are connected by wire bonding or flip-chip bonding.

[17] The optical module using the optical navigation sensor device of claim 15, further comprising: an external lens arranged on an optical path between the optical navigation sensor device and an external surface.

[18] The optical module using the optical navigation sensor device of claim 15, wherein the optical module is used in an optical mouse or an optical mouse embedded into a main body of an electronic device.

[19] A portable mouse comprising: an optical navigation sensor comprising a light source that generates light and a light detector that detects reflected light generated in the light source; a movement determiner that receives an electrical signal output from the optical navigation sensor and calculates a distance and direction according to movement; a key input unit that selects an item based on a pointer position; and a controller that receives signals from the movement determiner and the key input unit and controls data based on the movement distance and direction and a key input to be sent to an external electronic device using wireless communication, wherein the portable mouse is mounted in an electronic device in which local- area wireless communication is possible, and the optical navigation sensor has unit optical devices formed in an N x M matrix on a substrate, wherein at least one of the unit optical devices is a semiconductor light source having a light-emitting region and all other unit optical devices are light detectors.

[20] The portable mouse of claim 19, wherein the optical navigation sensor is configured by integrating the light source and the light detector on the same substrate.

[21] The portable mouse of claim 19, wherein Bluetooth is used for the local-area wireless communication.

[22] The portable mouse of claim 19, wherein ZigBee is used for the local-area wireless communication.

[23] The portable mouse of claim 19, wherein the optical navigation sensor has a structure for sensing light reflected by a human finger when light is emitted from the light source, or a structure for sensing light reflected from an external bottom surface.

[24] A portable mouse comprising: an optical navigation sensor comprising a light source that generates light and a light detector that detects reflected light generated in the light source; a movement determiner that receives an electrical signal output from the optical navigation sensor and calculates a distance and direction according to movement; a key input unit that selects an item based on a pointer position; and a controller that receives signals from the movement determiner and the key input unit and controls data based on the movement distance and direction and a key input to be sent to an external electronic device using wireless communication, wherein the portable mouse is mounted in an electronic device in which local- area wireless communication is possible, the optical navigation sensor has the light source arranged at its center and the light detector is separated into a plurality of independent light-detecting regions in a radial structure to detect reflected light from the light source, and the movement determiner senses continuous movement in a light detection direction when light is detected in the independent light-detecting regions.