Patent Publication Number: US-8987658-B2

Title: Packaged light detector semiconductor devices with non-imaging optical concentrators for ambient light and/or optical proxmity sensing, methods for manufacturing the same, and systems including the same

Description:
PRIORITY CLAIM 
     This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 61/730,692, which was filed Nov. 28, 2012. 
    
    
     BACKGROUND 
     Light detectors can be used, for example, as ambient light sensors or as part of optical proximity sensors. Since more and more light detectors are being integrated into devices, such as mobile phones, there is a desire to provide smaller and cheaper light detectors. Preferably, manufacturing of such light detectors should be relatively simple and should provide a high yield. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a perspective view of a packaged light detector semiconductor device (PLDSD) according to an embodiment. 
         FIG. 1B  shows a cross-sectional view of the PLDSD of  FIG. 1A , along line B-B. 
         FIG. 1C  shows a bottom view of the PLDSD of  FIG. 1A . 
         FIG. 2A  illustrates a profile of an exemplary compound parabolic concentrator (CPC) type of non-imaging optical concentrator. 
         FIG. 2B  illustrates light rays entering an entrance aperture of a CPC at an extreme angle of acceptance and being directed to an edge of an exit aperture of the CPC. 
         FIG. 2C  is a three-dimensional illustration of a CPC with a light ray entering the entrance aperture almost tangentially and reflecting many times around the interior of the CPC before emerging at the exit aperture. 
         FIG. 2D  is used to illustrate that an extreme angle of acceptance for a CPC, and more generally, a non-imaging optical concentrator, can be increased by filling an inner volume of the non-imaging optical concentrator with a light transmissive material. 
         FIG. 3A  shows a perspective view of a PLDSD according to a further embodiment. 
         FIG. 3B  shows a cross-sectional view of the PLDSD of  FIG. 3A , along line B-B. 
         FIG. 3C  shows a perspective view of a PLDSD according to another embodiment. 
         FIG. 3D  shows a cross-sectional view of the PLDSD of  FIG. 3C , along line D-D. 
         FIG. 3E  shows a perspective view of a PLDSD according to still another embodiment. 
         FIG. 3F  shows a cross-sectional view of the PLDSD of  FIG. 3E , along line F-F. 
         FIG. 4  is a high level flow diagram that is used to summarize methods for manufacturing PLDSDs in accordance with various embodiments. 
         FIG. 5  is a high level block diagram of a system that includes a PLDSD according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  shows a perspective view of a packaged light detector semiconductor device (PLDSD)  102 , according to an embodiment of the present invention.  FIG. 1B  shows a cross-sectional view of the PLDSD of  FIG. 1A , along line B-B.  FIG. 1C  shows a bottom view of the PLDSD  102  of  FIG. 1A . Referring to  FIG. 1A , the PLDSD  102  is shown as including a light detector die  104  attached to a die attach paddle  109  and encapsulated within a molding material  112 . In accordance with certain embodiments, the molding material  112  is an opaque molding material, such as, but not limited to, a black epoxy, or other opaque resin or polymer. 
     The light detector die  104  is shown as including an active light detector sensor region  106  used to produce a current or voltage indicative of the magnitude of detected light. The active light detector sensor region  106 , which can also be referred to as the active photosensor region  106 , includes one or more light detecting elements, each of which can be a photoresistor, a photovoltaic cell, a photodiode, a phototransistor, or a charge-coupled device (CCD), but is not limited thereto. Light detecting elements, such as those mentioned above, are examples of optoelectronic elements. The active photosensor region  106  is optionally covered by an optical filter  107  that absorbs and/or reflects at least some wavelengths of light before the light reaches the active photosensor region  106 . For example, where the PLDSD  102  is intended to be used as an ambient light sensor (ALS), the optical filter  107  can be designed to absorb and/or reflect light of wavelengths outside of the visible spectrum, including, but not limited to, infrared (IR) light. For another example, where the PLDSD  102  is intended to be used as an optical proximity sensor (OPS) together with an IR light source, the optical filter  107  can be designed to absorb and/or reflect light of wavelengths other than IR light, in which case, the optical filter  107  can be designed to absorb and/or reflect light within the visible spectrum. 
     The light detector die  104  includes die contacts  105  that are electrically connected to lead-frame fingers  108  (which can be referred to more generally as package contacts  108 ) by bond wires  110 . For example, one or more of the die contacts  105  can correspond to the anode(s) of the light detecting element(s) of the active photosensor region  106 , while one or more further die contacts  105  can correspond to the cathode(s) of the light detecting element(s). The light detector die  104  can also include amplifier circuitry, filter circuitry and/or other types of signal processing circuitry, in which case one or more of the electrical contacts  105  can correspond to such signal processing circuitry. 
     The PLDSD  102  includes a top surface  114 , a bottom surface  118  and a peripheral surface  116  extending between the top surface  114  and the bottom surface  118 . In this example, the top surface  114  of the PLDSD  102  is formed by a top surface of the molding material  112 , and the peripheral surface  116  is formed by the four sides of the molding material  112 . The package contacts  108  can be, e.g., electrically conductive lands, electrically conductive pads, or electrically conductive balls, but are not limited thereto. For example, it is also possible that the package contacts  108  can be electrically conductive pins or wires. In this example, the PLDSD  102  includes six package contacts  108  and an exposed portion of the die attach paddle  109  on the bottom surface  118  (as best seen in  FIG. 1C ), however the PLDSD  102  can include more or less than six electrical connectors. The die attach paddle  109  can alternatively, or additionally, be a ground plane for the PLDSD  102 . In accordance with an embodiment, the PLDSD  102  is a flat no-leads package. In accordance with a specific embodiment, the package contacts  108  form a land grid array. 
     The PLDSD  112  is shown as including a non-imaging optical concentrator  120  that collects and concentrates light for the active photosensor region  106 . In  FIGS. 1A and 1B  the non-imaging optical concentrator  120  is shown as being a circular compound parabolic concentrator (CPC). In alternative embodiments, the non-imaging optical concentrator  120  can be a rectangular CPC or a square CPC. In other embodiments, the non-imaging optical concentrator  120  can be a circular, rectangular or square compound elliptic concentrator (CEC). In still other embodiments, the non-imaging optical concentrator  120  can be a circular, rectangular or square compound hyperbolic concentrator (CHC). Unless stated otherwise, for the remainder of this description, the non-imaging optical concentrator  120  will be assumed to be a circular CPC. However, as just explained, the use of alternative types of non-imaging optical concentrators, such as those mentioned above, are also within the scope of an embodiment. 
     In certain embodiments, a reflective material  123  is disposed on an inner surface  122  of the non-imaging optical concentrator  120  (e.g., a CPC). The reflective material  123  can be a reflective metal such as gold, silver, a gold-alloy or a silver-alloy, or adielectric material such as magnesium fluoride, or a combination thereof, but is not limited thereto. 
     The non-imaging optical concentrator  120  includes an entrance aperture  126  and an exit aperture  128 , wherein the exit aperture  128  is smaller than the entrance aperture  126 . The non-imaging optical concentrator  120  (e.g., a CPC) collects light radiation at its entrance aperture  126  and transfers that energy efficiently to its exit aperture  128 . Substantially all radiant energy incident at the entrance aperture  126  and within a prescribed field-of-view (FOV) will be transferred to the smaller exit aperture  128 . By locating the active photosensor region  106  under the exit aperture  128 , the active photosensor region  106  receives substantially all of the radiant energy incident at the entrance aperture  126 . 
     In certain embodiments, an inner volume  124  (which can also be referred to as a cavity) of the non-imaging optical concentrator  120  is hollow. In alternative embodiments, the inner volume  124  of the non-imaging optical concentrator  120  is filled with a light transmissive material  125 , such as a light transmissive molding material. The light transmissive material  125  can be a light transmissive epoxy (e.g., a clear or tinted epoxy), or other light transmissive resin or polymer, but is not limited thereto. In certain embodiments, the light transmissive molding material  125  may have a pigment or other property that filters out (i.e., absorbs and/or reflects) light of certain wavelengths that are not of interest, while allowing light of wavelengths of interest to pass. A benefit of filling the non-imaging optical concentrator  120  with a light transmissive material  125  is that it prevents particles, such as dust particles, from getting into the non-imaging optical concentrator  120  and adversely affecting the sensitivity of the underlying active photosensor region  106 . Another benefit of filling the non-imaging optical concentrator  120  with the light transmissive material  125  is that it can increase the maximum angle of acceptance, as discussed in additional details below with reference to  FIG. 2D . In specific embodiments, a top surface of the light transmissive material  125  is flush with the top surface  124  of the molding material  112  within which the non-imaging optical concentrator  120  is molded. It is also within the scope of an embodiment that the non-imaging optical concentrator  120  is filled with multiple layers of different types of light transmissive material, having different indexes of refraction, so that the light transmissive material within the non-imaging optical concentrator  120  performs at least some optical filtering, in addition to, or in place of, the optical filter  107 . 
     Where the non-imaging optical concentrator  120  is a CPC, the irradiance (W/m 2 ) will be multiplied (concentrated) by the ratio of the entrance-to-exit aperture areas.  FIG. 2A  illustrates the geometry of an exemplary CPC profile. The CPC profile is designed such that light rays entering the entrance aperture  126  at the extreme angle of acceptance, ±θ max , will pass through the parabola focus point, which will form the edge of the exit aperture  128 , as illustrated in  FIG. 2A . The three-dimensional CPC is formed by rotating the parabola profile about the concentrator axis, not the parabola axis, as illustrated in  FIG. 2A .  FIG. 2B  goes further to illustrate this point, showing many light rays entering the entrance aperture  126  of the CPC at the extreme angle of acceptance and being directed to the edge of the exit aperture  128 . Light rays incident at the entrance aperture  126  at less than the extreme angle of acceptance (θ max ) will emerge from the exit aperture  128  more toward the center of the aperture. While more complex, the operation of the CPC is essentially the same in three dimensions, as shown in  FIG. 2C . In  FIG. 2C , a light ray is shown entering the entrance aperture  126  almost tangentially and reflecting many times around the interior of the CPC before emerging at the exit aperture  128 . 
     The defining equations for the design of a CPC are provided below. If the extreme angle of acceptance is θ max , and the diameter of the exit aperture is 2α′, then the focal length (f) of the parabola is given by 
     
       
         
           
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     In a specific embodiment, the extreme angle of acceptance (θ max ), which defines the FOV, was selected to be 22.7761°, and the exit aperture diameter (2α′) was chosen as 0.2 mm. From the above equations, the entrance aperture diameter (2α) is 0.5166 mm, and the length (L) is 0.8534 mm. The ratio of the areas of the entrance aperture  123  and the exit aperture  128  is 6.6719, which is the concentration factor for the CPC in this example. 
     Where the inner volume  124  is filled with the light transmissive material  125 , the actual external extreme angle of acceptance (θ′ max ) for the CPC assembly will be the extreme angle of acceptance is (θ max ) explained above, multiplied by the refractive index of the light transmissive material  124  (e.g., a clear epoxy material), 1.5367 for example. Thus, the FOV for the CPC assembly in this example will be ±35°. In other words, filling the inner volume  124  with a light transmissive material  125  having a refractive index that is greater than one (i.e., &gt;1) increases the extreme angle of acceptance from θ max  to θ′ max , as illustrated in  FIG. 2D . 
     The use of the non-imaging optical concentrator  120  enables the active photosensor region  106  and the entire package to be reduced in size. For example, to achieve a predetermined sensitivity, the use of the non-imaging optical concentrator  120  enables the active photosensor region  106  to be reduced to about one-third the area that would be required if a non-imaging optical concentrator (and specifically, a CPC) were not used. 
     If the area of the active photosensor region  106  were much larger than the area of exit aperture  128 , then a large area of the active photosensor region  106  would be wasted because it would not be responsive to incident light. If the area of the active photosensor region  106  were smaller than the area of the exit aperture  128 , than some of the light that reached the exit aperture  128  would not be incident on the active photosensor region  106 . Accordingly, in certain embodiments, an area of the exit aperture  128  is substantially the same as or smaller than an area of the active photosensor region  106  so that substantially all of the light that reaches the exit aperture  128  is directed toward the active photosensor region  106 . In specific embodiments, an area of the exit aperture  128  and an area of the active photosensor region  106  are within 20% of one another. For example, an area of the active photosensor area  106  is within the range of 100% to 120% of the area of the exit aperture  128 . 
     Since the volume external to the non-imaging optical concentrator  120  does not contribute to the photosensor irradiance, the molding material  112  does not need to be a light transmissive optical-grade material. Indeed, the molding material  112  may be completely opaque. A benefit of the molding material  112  being opaque is that the underlying active photosensor region  106  is only responsive to light that has entered the non-imaging optical concentrator  120  through the entrance aperture  126 . 
     In accordance with specific embodiments of the present invention, the PLDSD  102  is for use as an ambient light sensor (ALS), and thus, can alternatively be referred to as an ALS. When used as an ALS, because of the inclusion of the non-imaging optical concentrator  120 , the area of the active photosensor region  106  of the PLDSD  102  can be reduced by more than 2-to-1 compared to conventional packages, while the average irradiance on the active photosensor region can be increased by almost 5-to-1, and the peak irradiance can be increased by more than 10-to-1. Alternatively, the PLDSD  102  can be used, along with a light source, as part of an optical proximity sensor (OPS). 
       FIG. 3A  shows a perspective view of a PLDSD according to a further embodiment.  FIG. 3B  shows a cross-sectional view of the PLDSD of  FIG. 3A , along line B-B. In this embodiment, a light detector die  304  includes two active photosensor regions  306  and  336 , one of which is for use as an ALS, and the other one of which is for use with a light source as part of an OPS. For this discussion, it will be assumed that the active photosensor region  306  is for an ALS, and the active photosensor region  336  is for use as part of an OPS. The light detector die  304  is encapsulated within a molding material  312 , which can be an opaque molding material, such as, but not limited to, a black epoxy, or other opaque resin or polymer. 
     Each active photosensor region  306 ,  336 , which is used to produce a corresponding current or voltage indicative of the magnitude of respective detected light, includes one or more light detecting elements, examples of which were described above. The active photosensor region  306  is optionally covered by an optical filter  307  that absorbs and/or reflects wavelengths outside of the visible spectrum, including, but not limited to, IR light. The active photosensor region  336  is optionally covered by an optical filter  337  designed to absorb and/or reflect light of wavelengths other than IR light, in which case, the optical filter  337  can be designed to absorb and/or reflect light within the visible spectrum. 
     The light detector die  304  includes die contacts  305  that are connected to lead-frame fingers  308  (which can be referred to more generally as package contacts  308 ) by bond wires  310 . The light detector die  304  can also include amplifier circuitry, filter circuitry and/or other types of signal processing circuitry. 
     The PLDSD  302  includes a top surface  314 , a bottom surface  318  and a peripheral surface  316  extending between the top surface  314  and the bottom surface  318 . In this example, the top surface  314  of the PLDSD  302  is formed by a top surface of the molding material  312 , and the peripheral surface  316  is formed by the four sides of the molding material  312 . The package contacts  308  can be, e.g., electrically conductive lands, electrically conductive pads, electrically conductive balls, electrically conductive pins, or wires, but are not limited thereto. In this example, the PLDSD  302  includes six package contacts  308  and an exposed portion of die attach paddle  309  on the bottom surface  318 , however the PLDSD  302  can include more or less than six electrical connectors. The die attach paddle  309  can alternatively, or additionally, be a ground plane for the PLDSD  302 . In accordance with an embodiment, the PLDSD  302  is a flat no-leads package. In accordance with a specific embodiment, the package contacts  308  form a land grid array. 
     The PLDSD  302  is shown as including a first non-imaging optical concentrator  320  that collects and concentrates light for the active photosensor region  306 , and a second non-imaging optical concentrator  340  that collects and concentrates light for the active photosensor region  336 . In  FIGS. 3A and 3B  each of the non-imaging optical concentrators  320 ,  340  is shown as being a CPC, but can alternatively be another type of non-imaging optical concentrator, such as a CEC or CHS. It is also possible that two different types of non-imaging optical concentrators are used, e.g., the non-imaging optical concentrator  320  can be a circular CPC, while the non-imaging optical concentrator  340  can be a square CEC. In certain embodiments, a reflective material  323  is disposed on an inner surface  322  of the non-imaging optical concentrator  320 , and a reflective material  343  is disposed on an inner surface  342  of the non-imaging optical concentrator  340 . Exemplary types of reflective materials were discussed above with reference to  FIGS. 1A and 1B . The non-imaging optical concentrator  320  includes an entrance aperture  326  and an exit aperture  328 . Similarly, the non-imaging optical concentrator  340  includes an entrance aperture  346  and an exit aperture  348 . An inner volume  324  (which can also be referred to as a cavity) of the non-imaging optical concentrator  320  can be hollow, or can be filled with a light transmissive material  325 . Similarly, an inner volume  344  of the non-imaging optical concentrator  340  can be hollow, or can be filled with a light transmissive material  345 . Exemplary types of light transmissive materials were discussed above with reference to  FIGS. 1A and 1B , as were benefits of filling the inner volume of a non-imaging optical concentrator with such a material. 
       FIG. 3C  shows a perspective view of a PLDSD  302 ′ according to another embodiment.  FIG. 3D  shows a cross-sectional view of the PLDSD of  FIG. 3C , along line D-D. The PLDSD  302 ′ of  FIGS. 3C and 3D  is similar to the PLDSD  302  described with reference to  FIGS. 3A and 3B , except that a recess  350  is added in the molding material  312 , which enables a non-imaging optical concentrator  320 ′ below the recess  350  to have a shorter length than the non-imaging optical concentrator  340  without the recess  350 . For example, the recess  350  enables the non-imaging optical concentrator  320 ′ for use as part of an ALS to be shorter in length than the non-imaging optical concentrator  340  for use as part of an OLS. More generally, the recess  350  enables a single PLDSD to include non-imaging optical concentrators of different lengths. 
       FIG. 3E  shows a perspective view of a PLDSD  302 ″ according to another embodiment.  FIG. 3F  shows a cross-sectional view of the PLDSD of  FIG. 3E , along line F-F. The PLDSD  302 ″ of  FIGS. 3E and 3F  is similar to the PLDSD  302  described with reference to  FIGS. 3A and 3B , except that a light directing baffle  360  is added in the molding material  312 , which enables the FOV for one of the non-imaging optical concentrators (labeled  340 ″) to be increased in the direction of a light source  301  (e.g., an IR LED) that is used as part of the OPS. More generally, a light directing baffle  360  can be used to increase the FOV for a non-imaging optical concentrator. It is also within the scope of an embodiment for a single PLDSD to include both a recess (the same as, or similar to, the recess  350 ) and a light directing baffle (the same as, or similar to, the light directing baffle  360 ). For example, a recess can be located above the non-imaging optical concentrator that concentrates light for an active photosensor region used as an ALS, and a light directing baffle can be used with the non-imaging optical concentrator that concentrates light for an active photosensor region used as part of an OPS. 
     In the above description, and the previously described FIGS., the light detector dies  104  and  304  were described and shown as being attached to die paddles of a lead-frame. In alternative embodiments, portions of bottom surfaces of the dies  104  and  304  can be attached directly to portions of top surfaces of lead-fingers of a lead-frame not having a die paddle, as is the case with Chip-on-Lead (CoL) packages. In other embodiments, bottom surfaces of the light detector dies  104  and  304  can be attached directly to the top surface of a printed circuit board (PCB), as is the case with Chip-on-PCB packages. In other words, bottom surfaces of the dies  104  and  304  can be attached to top surfaces of various types of package substrates, including lead-frames (which may or may not include die paddles) and PCBs, but are not limited thereto. In all such embodiments, wire bonds can be used to electrically connect die contacts (of the dies  104  and  304 ) to package contacts (of the package substrates), wherein the package contacts are used to electrically connect the resulting PLDSDs to external circuitry. Through silicon vias (TSVs) can be used in place of, or in addition to, wire bonds. In further embodiments, the active sensor regions(s) can be located on the backside of a die, and flip chip bonding technology can be used to electrically connect die contacts to package contacts. 
       FIG. 4  is a high level flow diagram that is used to summarize methods for manufacturing PLDSDs in accordance with various embodiments. Referring to  FIG. 4 , at step  402 , each of a plurality of the light detector dies (e.g.,  104  or  304 ) is attached to a package substrate. This can be accomplished by attaching bottom surfaces of the dies to die paddles of a lead-frame using an adhesive. Alternatively, bottom surfaces of the dies can be attached directly to portions of top surfaces of lead-frame fingers. In still other embodiments, bottom surfaces of dies can be attached to a PCB. 
     At step  404 , the light detector dies (and more specifically, contacts of the dies) are electrically connected to package contacts of the package substrate. The package contacts of the package substrate can be, e.g., lead-frame fingers of a lead-frame, or wire bond pads of a PCB, but are not limited thereto. Step  404  can be performed using wire bonding, as was explained above. Alternatively, TSVs can be used in place of wire bonds. In further embodiments, the active sensor regions(s) can be located on the backside of a die, and flip chip bonding technology can be used to electrically connect die contacts to package contacts. 
     At step  406 , molding is performed to mold, from a molding material (e.g.,  112 ,  312 ), one or more non-imaging optical concentrator (e.g.,  120 ,  320 ,  320 ′,  340 ,  340 ″) for each active photosensor region of the plurality of light detector dies. As was described above, each non-imaging optical concentrator includes an entrance aperture and an exit aperture axially aligned with one another and with an active photosensor region of the underlying light detector die. In specific embodiments, the molding material used at step  406  is an opaque molding material, such as, but not limited to, a black epoxy, or other opaque resin or polymer. In addition to being used to form the non-imaging optical concentrators, the molding material also encapsulates portions of the upper surfaces of the light detector dies that extend beyond the exit apertures of the non-imaging optical concentrators. At step  406 , recesses (e.g.,  350 ) and/or light directing baffles (e.g.,  360 ), which were described above, can also be molded. In accordance with specific embodiments, transfer molding is performed at step  406 . In alternative embodiments, other types of molding techniques can be used, including, but not limited to, compression molding, casting and injection molding. 
     At step  408 , inner surfaces of the molded non-imaging optical concentrators are roughened, e.g., using an Argon-Oxygen plasma etch, so that a reflective material (deposited at step  414 ) will adhere to the inner surfaces. 
     At step  410 , a sacrificial photoresist is deposited on the surface of an upper surface of the molded structure that results from step  406 , and within the exit apertures of the non-imaging optical concentrators so that the sacrificial photoresist covers the active sensor regions, or optical filters covering the active sensor regions. This sacrificial photoresist is used to enable excess reflective material (deposited at step  414 ) to be removed at a later step (at step  416 ). 
     At step  412 , inner surfaces of the non-imaging optical concentrators are plasma cleaned to remove debris (that may remain from the roughening performed at step  408 ) and/or remove excess photoresist (that may have been inadvertently deposited on the inner surfaces of the non-imaging optical concentrators at step  410 ). 
     At step  414 , a reflective material (e.g.,  123 ,  323 ,  343 ) is deposited on the inner surfaces of the non-imaging optical concentrators. As mentioned above, the reflective material can be a reflective metal such as gold, silver, a gold-alloy or a silver-alloy, or a dielectric material such as magnesium fluoride, or a combination thereof, but is not limited thereto. 
     At step  416 , the sacrificial photoresist (deposited at step  410 ) is removed, e.g., using a photoresist stripper. 
     At step  418 , a light transmissive material (e.g.,  125 ,  325 ,  345 ) is deposited within inner volumes of the non-imaging optical concentrators, thereby filling at least a portion of the inner volume of each of the non-imaging optical concentrators. As mentioned above, the light transmissive material can be a light transmissive epoxy (e.g., a clear or tinted epoxy), or other light transmissive resin or polymer, but is not limited thereto. In specific embodiments, a top surface of the light transmissive material deposited at step  416  is flush with the top surface of the molding material used to mold the non-imaging optical concentrators at step  406 . 
     At step  420 , the light transmissive material is cured. For example, the light transmissive material can be thermal cured within an oven heated to a temperature, e.g., between 90 and 110 degrees Celsius, depending on the specific light transmissive material used. Other ways of curing the light transmissive material can be used, including, but not limited to, using ultraviolet (UV) radiation. 
     At step  422 , singulation is performed to thereby separate the package substrate and molding material into a plurality of separate PLDSDs each of which includes one of the light detector dies and one or more non-imaging optical concentrators that is/are at least partially filled with the light transmissive molding material. Exemplary resulting PLDSDs include the PLDSDs  102 ,  302 ,  302 ′ and  302 ″ described above. 
     In the above described embodiments, already segmented dies were described as being attached to a package substrate (at step  402 ), die contacts were electrically connected to package contacts of the package substrate (at step  404 ), and non-imaging optical concentrators were thereafter molded (at step  406 ). In alternative embodiments, the non-imaging optical concentrators can be molded right on a wafer that is not segmented into separate dies until the final singulation is performed (at step  422 ). Such alternative embodiments provide for a full chip-scale packaging process in which TSVs can be used to provide electrical connections between an active side of each die and the other side of each die. 
       FIG. 5  is a high level block diagram of a system  510  that includes a PLDSD according to an embodiment. PLDSDs of embodiments of the present invention can be used in various systems, including, but not limited to, mobile phones, tablets, personal data assistants, laptop computers, netbooks, other handheld-devices, as well as non-handheld-devices. Referring to the system  510  of  FIG. 5 , for example, a PLDSD  502  (e.g., which can be one of the PLDSDs  102 ,  302 ,  302 ′ or  302 ″) can be used to control whether a subsystem  506  (e.g., a touch-screen, display, backlight, virtual scroll wheel, virtual keypad, navigation pad, etc.) is enabled or disabled, and/or to determine whether to adjust (e.g., a brightness associated with) the subsystem  506 . For example, where the PLDSD  502  includes an active photosensor region that is used together with a light source  501  (e.g., an IR light emitting diode) as an OPS, the PLDSD  502  can be used detect when an object  508 , such as a person&#39;s finger, is approaching, and based on the detection either enable (or disable) the subsystem  506 . For example, an output of the PLDSD  502  can be provided to a comparator and/or processor  504  which can, e.g., compare the output of the PLDSD to one or more threshold, to determine whether the object  508  is within a range where the subsystem  506  should be enabled (or disabled, depending on what is desired). Multiple thresholds (e.g., stored digital values) can be used, and more than one possible response can occur based on the detected proximity of the object  508 . For example, a first response can occur if the object  508  is within a first proximity range, and a second response can occur if the object  508  is within a second proximity range. Exemplary responses can include starting or stopping, or otherwise adjusting the subsystem  506 . 
     Alternatively, or additionally, the PLDSD  502  can include an active photosensor region that is used as an ALS. For example, an output of the PLDSD  502  can be provided to the comparator and/or processor  504 , which can determine how to adjust the brightness of the subsystem  506  (e.g., a display or backlight).  FIG. 5  also shows that a driver  500  can be used selectively drive one or more light emitting elements of the light source  501 . 
     In  FIG. 5 , the dotted line  512  represents light that originated from the light source  501 , reflected off an object  508 , and is detected by an active photosensor region of the PLDSD  502  that is used together with the light source  512  as an OPS. In  FIG. 5 , the dashed line  514  represents ambient light that is detected by an active photosensor region of the PLDSD  502  that is used as an ALS. As was described in additional detail above, in accordance with specific embodiments, one or more non-imaging optical concentrator can be used to collect and concentrate the light  512  and/or  514  for one or more active photosensor regions of the PLDSD  502 . 
     Embodiments of the present invention have been described above with the aid of functional building blocks illustrating the performance of specified functions and relationships thereof. The boundaries of these functional building blocks have often been defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Any such alternate boundaries are thus within the scope and spirit of the claimed invention. 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. 
     The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.