Abstract:
A coverless linear light source light guide with hooded bracket for holding a light emitting diode (LED) module to the light guide is disclosed. The hooded bracket is disposed around the light receiving end of the light guide and comprises a hood top, a hood back, two hood sides, and two hood grasps disposed on the hood sides. The hood back comprises the light receiving end of the light guide where light enters the light guide. The hood grasp comprises grasping elements that mate with grasping elements of the LED module to securely hold the LED module to the light guide. The hooded bracket ensures that the distance between the LED module and the light guide and the angle of the LED module and the light guide is constant which maintains optimal alignment and proximity in order to conserve received light intensity and maintain uniformity of emitted light.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to lighting devices. More specifically, the present invention discloses a linear light source light guide with a hooded bracket for securely attaching a light emitting diode module to the light guide to maintain optimal alignment and proximity in order to conserve received light intensity and maintain uniformity of emitted light of a coverless linear light source. 
     2. Description of the Prior Art 
     Linear light sources are used in scanners to light to illuminate an object. When the object is illuminated, the scanner is able to acquire an image of the object. 
     However, the performance of the linear light source greatly affects the quality of the acquired image. If the emitted light is not uniform or varies in intensity, the object will not be effectively lit and the acquired image will be of inferior quality with areas of the object too light and areas of the object too dark. 
     In the conventional scanner light source a light emitting diode shines light into a light bar that is positioned next to a light emitting diode. Since they are not connected, vibration from moving the device or from operating the scanner causes the light bar to change proximity to the light emitting diode. When the light bar moves away from the light emitting diode, the amount and intensity of light entering the light bar changes and decreases. As a result, the brightness and uniformity of emitted light is not constant and reliable. 
     Additionally, in the conventional light source the angle of the light emitting diode and the light bar can easily change or vary. Since the light emitting diode and the light bar are not consistently at the same angle the optimal uniformity and brightness of emitted light is not obtained and the conventional light source does not provide an emitted light of superior quality. 
     Therefore, there is need for an improved cost effective linear light source with superior light intensity and light uniformity that utilizes a light guide with a hooded bracket for holding a light emitting diode module to the light guide at a constant and optimal distance and angle. 
     SUMMARY OF THE INVENTION 
     To achieve these and other advantages and in order to overcome the disadvantages of the conventional method in accordance with the purpose of the invention as embodied and broadly described herein, the present invention provides a linear light source light guide with a hooded bracket for securely attaching a light emitting diode module to the light guide to maintain optimal alignment and proximity in order to conserve received light intensity and maintain uniformity of emitted light. 
     The hooded bracket is disposed around the light receiving end of the light guide and comprises a hood top, a hood back, two hood sides, and two hood grasps disposed on the hood sides. 
     The hood back comprises the light receiving end of the light guide where light enters the light guide. 
     The hood grasp comprises grasping elements, for example, a tab, an ear, a hole, a slot, a groove, an indentation, a post, or a slide rail which mate with grasping elements of a light emitting diode (LED) module to securely hold the LED module to the light guide. 
     Since the LED module is held to the light guide, the distance between the LED module and the light guide and the angle of the LED module and the light guide is constant. As a result, the hooded bracket for attaching the light emitting diode module to the light guide maintain optimal alignment and proximity in order to conserve received light intensity and maintain uniformity of emitted light of the coverless linear light source. 
     The present invention provides a coverless linear light source with improved light uniformity and light intensity without needing or using a reflective cover or housing around the light guide. Eliminating the reflective cover or housing reduces production costs including labor, material, tooling, inventory, and assembly costs as well as reducing manufacturing complexity thus saving time. This is an advantage of the present invention 
     The light guide further comprises a light emitting surface where light exits the light guide and a light reflecting patterned surface for reflecting light towards the light emitting surface. The light reflecting patterned surface comprises a plurality of peaks and a plurality of valleys with a valley disposed between each peak. 
     As the light reflecting patterned surface extends along the light guide the depth of each valley increases. At the pattern start, which is closest to the LEDs, the depth of the valley is shallowest and the height of the peak from the floor of the valley is the shortest. 
     As the light reflecting patterned surface continues away from the LEDs the depth of the valley gradually increases and the height of the peak from the floor of the valley continues to gradually increase. 
     At the pattern end, which is farthermost away from the LEDs, the depth of the valley is deepest and the height of the peak from the floor of the valley is the tallest. 
     At the pattern end the floor of the valley is narrowest and the pattern is or approaches a sawtooth pattern where the valley is or approaches a v-shape. Moving towards the LEDs the floor of the valley becomes flat and gradually widens. At the pattern start  230  the floor of the valley is widest. 
     When power is applied conductive pins of the LED module, which are electrically connected to LEDs, the LEDs illuminate and emit light into the light receiving end of the light guide. The light travels or propagates through the light guide and is reflected by the light reflecting patterned surface towards the light emitting surface of the light guide and the light exits the light guide through the light emitting surface. 
     A plurality of side surfaces are disposed between the light emitting surface and the light reflecting patterned surface. 
     A side groove and a top groove are provided for allowing the light guide to be held to a main housing of the scanner sub-module. The main housing&#39;s side clips hold the side groove and top clips hold the top groove. 
     These and other objectives of the present invention will become obvious to those of ordinary skill in the art after reading the following detailed description of preferred embodiments. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is an exploded view drawing illustrating a light guide with hooded bracket and a light emitting diode module of a coverless linear light source according to an embodiment of the present invention; 
         FIG. 2A  is a drawing illustrating a light guide with a hooded bracket according to an embodiment of the present invention; 
         FIG. 2B  is a cross-sectional drawing illustrating a light guide with a hooded bracket according to an embodiment of the present invention; 
         FIG. 2C  is an end view drawing illustrating a hooded bracket of a light guide according to an embodiment of the present invention; 
         FIG. 2D  is a cross-sectional drawing illustrating a light guide with a hooded bracket according to an embodiment of the present invention; 
         FIG. 2E  is an end view drawing illustrating a hooded bracket of a light guide according to an embodiment of the present invention; 
         FIG. 2F  is a cross-sectional drawing illustrating a light guide with a hooded bracket according to an embodiment of the present invention; 
         FIG. 2G  is an end view drawing illustrating a hooded bracket of a light guide according to an embodiment of the present invention; 
         FIG. 2H  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 2I  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 2J  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 2K  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 2L  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 2M  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 2N  is a drawing illustrating a hood grasp of a hooded bracket according to an embodiment of the present invention; 
         FIG. 3A  is a drawing illustrating a light emitting diode module with module grasps according to an embodiment of the present invention; 
         FIG. 3B  is a drawing illustrating a light emitting diode module with module grasps according to an embodiment of the present invention; 
         FIG. 3C  is a drawing illustrating a coverless linear light source according to an embodiment of the present invention; 
         FIG. 4A  is a drawing illustrating a coverless linear light source according to an embodiment of the present invention; 
         FIG. 4B  is a bottom view drawing of a coverless linear light source with a light guide with a light reflecting patterned surface according to an embodiment of the present invention; 
         FIG. 4C  is a cross-sectional view drawing of a coverless linear light source with a light guide with a light reflecting patterned surface according to an embodiment of the present invention; 
         FIG. 4D  is a top view drawing of a coverless linear light source according to an embodiment of the present invention; 
         FIG. 4E  is a side view drawing of a coverless linear light source according to an embodiment of the present invention; 
         FIG. 4F  is a drawing illustrating a coverless linear light source according to an embodiment of the present invention; 
         FIG. 5A  is a cross-sectional view drawing illustrating a light guide of a coverless linear light source according to an embodiment of the present invention; 
         FIG. 5B  is a cross-sectional view drawing illustrating a light guide of a coverless linear light source according to an embodiment of the present invention; 
         FIG. 6A  is a cross-sectional side view drawing illustrating light paths of the light guide with light reflecting patterned surface according to an embodiment of the present invention; 
         FIG. 6B  is a cross-sectional drawing illustrating light paths of the light guide with light reflecting patterned surface according to an embodiment of the present invention; 
         FIG. 6C  is a cross-sectional drawing illustrating emitted light paths of the light guide according to an embodiment of the present invention; 
         FIG. 7A  is a drawing illustrating a coverless linear light source, lens array, main housing, and printed circuit board according to an embodiment of the present invention; 
         FIG. 7B  is a drawing illustrating a coverless linear light source, lens array, and main housing according to an embodiment of the present invention; 
         FIG. 7C  is a top view drawing illustrating a coverless linear light source, lens array, and main housing according to an embodiment of the present invention; and 
         FIG. 7D  is a cross-sectional drawing illustrating a coverless linear light source, lens array, printed circuit board, and main housing according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Refer to  FIG. 1  is an exploded view drawing illustrating a light guide with hooded bracket and a light emitting diode module of a coverless linear light source according to an embodiment of the present invention. 
     The light emitting diode (LED) module  300  comprises a plurality of LEDs disposed in a module body. A plurality of conductive pins  320  extend below the module body for electrically connecting the plurality of LEDs  310  to conductive traces on a printed circuit board (PCB) in the main housing. The LED module  300  further comprises module grasps  330  disposed on sides of the module body. 
     The light guide  200  comprises an elongated polygonal transparent material. Light emitted by the LED module  300  enters an end of the light guide  200  and is reflected by a patterned surface of the light guide  200 . The light eventually exits the light guide through a light emitting surface of the light guide  200 . 
     The light guide  200  further comprises a hooded bracket  220  with hood grasps  260 . The hooded bracket  220  is disposed on the light receiving end of the light guide  200 . 
     The LED module  300  is inserted into the hooded bracket  220  and the hooded bracket  220  holds the LED module  300  and the light guide  200  together. 
     Refer to  FIG. 2A , which is a drawing illustrating a light guide with a hooded bracket according to an embodiment of the present invention. 
       FIG. 2A  shows a close up view of the light guide  200  and the hooded bracket  220 . The hooded bracket  220  comprises a hood top  262 , a hood back  263 , two hood sides  261 , and two hood grasps  260  disposed in the hood sides  261 . 
     The hood back  263  comprises the light receiving end of the light guide  200  where light enters the light guide  200 . 
     The hood grasp  260  comprises grasping elements, for example, a tab, an ear, a hole, a slot, a groove, an indentation, a post, or a slide rail which mate with grasping elements of a light emitting diode (LED) module. 
     Refer to  FIGS. 2B-2N , which are drawings illustrating hooded brackets and hood grasps of light guides according to embodiments of the present invention. 
     In the embodiment illustrated in  FIG. 2B  the hooded bracket  220  of the light guide  200  comprises hood grasps  260  that extend from the hood sides  261  to form a slotted front in the hooded bracket  220 . When the LED module is inserted into the hooded bracket  220  the hood grasps  260  press against the back of the LED module body and hold the LED module inside the hooded bracket  220 . The slot between the hood grasps  260  allow heat to dissipate from the heatsinks on the LED module. 
     In the embodiment illustrated in  FIG. 2C  the hood grasp  260  comprises a wall on the front side of the hooded bracket with an opening in one of the hood side. The LED module can be slid into the hooded bracket through the opening in the bottom and the hood side. 
     In the embodiment illustrated in  FIGS. 2D and 2E  the hood grasps  260  comprise flexible wings that extend from the hood sides  261 . Since the hood grasps  260  are flexible a variety of sizes of LED modules can be utilized. As the LED module is inserted into the hooded bracket  220  the hoods grasps adjust to the size or thickness of the LED module body and apply pressure against the LED module to hold it inside the hooded bracket  220 . 
     In the embodiment illustrated in  FIGS. 2F and 2G  the hood grasp  260  comprise a hood front spanning the hood sides  261  to form a hooded bracket  220  that is enclosed except for the opening in the bottom of the hooded bracket. This allows the hooded bracket  220  to surround the sides and top of the LED module body to hold it inside the hooded bracket  220  while allowing the conductive pins to extend through the bottom opening in the hooded bracket  220 . 
     In the embodiment illustrated in  FIG. 2H  the hood grasps  260  comprise indentations in the hood sides  261 . 
     In the embodiment illustrated in  FIG. 2I  the hood grasps  260  comprise ears. 
     In the embodiment illustrated in  FIG. 2J  the hood grasps  260  comprise posts. 
     In the embodiment illustrated in  FIG. 2K  the hood grasps  260  comprise slides extending from the interior of the hood sides  261 . 
     In the embodiment illustrated in  FIG. 2L  the hood grasps  260  comprise grooves extending into the hood sides  261 . 
     In the embodiment illustrated in  FIG. 2M  the hood grasps  260  comprise flexible tabs formed in the hood sides  261 . The flexible tabs can expand outwards when the LED module is inserted and then collapse back to the original position after the LED module is inserted. 
     In the embodiment illustrated in  FIG. 2N  the hood grasps  260  comprise holes in the hood sides  261 . 
     It should be noted that the hood grasps of the hooded bracket and the module grasps of the LED module are mating elements and interchangeable. Embodiments detailed describing the hood grasps are also applicable to the module grasps. For example, in an embodiment where the hood grasp is a post and the module grasp is a hole or indentation, in another embodiment the hood grasp is a hole or indentation and the module grasp is a post. 
     Refer to  FIGS. 3A-3B , which are drawings illustrating a light emitting diode module with module grasps according to an embodiment of the present invention. 
     The light emitting diode (LED) module  300  comprises a module body comprising a module top  301  and a module back  312 . A plurality LEDs  310  is disposed in the front of the module body. A plurality of conductive pins  320  extend below the module body for electrically connecting the plurality of LEDs  310  to conductive traces on a printed circuit board (PCB) in the main housing. 
     A plurality of heatsinks  311  is disposed in the module back  312  for dissipating heat generated by the LEDs  310 . 
     The LED module  300  further comprises module grasps  330  disposed on sides of the module body. The module grasp  330  comprises grasping elements, for example, a tab, an ear, a hole, a slot, a groove, an indentation, a post, or a slide rail which mate with the hood grasp of the hooded bracket. 
     Refer to  FIG. 1  and  FIG. 3C , which are drawings illustrating a light guide and light emitting diode module of a coverless linear light source according to an embodiment of the present invention. 
     To assemble the coverless linear light source  100  of the present invention the LED module  300  is inserted into the hooded bracket  220  of the light guide  200 . 
     The hood top  262  contacts the module top  301  and the hood sides  261  contact the sides of the module body of the LED module  300 . The size of the interior of the hooded bracket  220  is formed to fit and hold the LED module  300  in the hooded bracket  220 . 
     To hold the LED module  300  and the hooded bracket  220  even more securely, the hood grasps  260  mate with the module grasps  330  and attach the LED module  300  and the hooded bracket together. 
     Since the LED module  300  and the hooded bracket  220  are connected together, the present invention offers a far superior conservation of light emitted by the LED module  300  and entering the light guide  200 . Additionally, the hooded bracket  220  maintains the LED module  300  at an optimal angle to the light guide  220  to improve light intensity. 
     Refer to  FIG. 4A , which is a drawing illustrating a coverless linear light source according to an embodiment of the present invention. 
     When the coverless linear light source  100  is assembled the alignment and positioning of the light guide  200  and the LED module  300  are as shown in  FIG. 4A . The light receiving end of the light guide  200  is positioned over the LEDs of the LED module  300 . When power is applied to the conductive pins  320  the LEDs illuminate and emit light into the light guide  200 . The light travels through the light guide  200  and is reflected by the light reflecting patterned surface  210  and exits the light guide  200  through the light emitting surface  216 . 
     Refer to  FIGS. 4B-4F , which are drawings illustrating a coverless linear light source with a light guide with a light reflecting patterned surface according to an embodiment of the present invention, and to  FIG. 6A , which is a cross-sectional side view drawing illustrating light paths of the light guide with light reflecting patterned surface according to an embodiment of the present invention. 
     The light reflecting patterned surface  210  of the light guide  200  comprises a pattern start  230  and a pattern end  240 . The pattern start  230  is disposed closest to the hooded bracket  220  and light receiving end of the light guide  200 . The pattern end is at the opposite end of the light guide  200  farther away from the light receiving end. 
     The light reflecting patterned surface  210  comprises a plurality of peaks  231  and a plurality of valleys  232  with a valley  232  disposed between each peak  231 . 
     As the light reflecting patterned surface  210  extends along the light guide  200  the depth of each valley  232  increases. At the pattern start  230 , which is closest to the LEDs  310 , the depth of the valley  232  is shallowest and the height of the peak  231  from the floor of the valley  232  is the shortest. 
     As the light reflecting patterned surface  210  continues away from the LEDs  310  the depth of the valley  232  gradually increases and the height of the peak  231  from the floor of the valley  232  continues to gradually increase. 
     At the pattern end  240 , which is farthermost away from the LEDs  310 , the depth of the valley  232  is deepest and the height of the peak  231  from the floor of the valley  232  is the tallest. 
     At the pattern end  240  the floor of the valley  232  is narrowest and the pattern is or approaches a sawtooth pattern where the valley is or close to a v-shape. Moving towards the LEDs the floor of the valley  232  becomes flat and gradually widens. At the pattern start  230  the floor of the valley  232  is widest. 
     Refer to  FIG. 5A , which is a cross-sectional view drawing illustrating a light guide of a coverless linear light source according to an embodiment of the present invention. 
     In the embodiment illustrated in  FIG. 5A  the light guide  200  comprises a light reflecting patterned surface  210  for reflecting light towards a light emitting surface  216  and the reflected light exits the light guide  200  via the light emitting surface  216 . 
     A side groove  250  comprises a two-sided notch disposed on the right corner of the light emitting surface  216 . The side groove  250  comprises a side groove upper surface  217  and a side groove lower surface  218 . A side clip of a main housing extends into the side groove  250  and grasps the side groove lower surface  218  to hold the light guide  200  in a main housing. The side groove upper surface  217  contacts the right corner of the light emitting surface  216  and the side groove lower surface  218  contacts a top corner of a right side surface  219 . 
     A top groove  270  comprises a two-sided obtuse angle notch. The top groove  270  comprises a top groove upper surface  214  and a top groove lower surface  213 . A top clip of a main housing extends into the top groove  270  and grasps the top groove lower surface  213  to hold the light guide  200  in a main housing. The top groove upper surface  214  contacts a bottom corner of a left side surface  215  and the top groove lower surface  213  contacts a top corner of an angled side surface  212 . 
     A plurality of side surfaces are disposed between the light reflecting patterned surface  210  and the light emitting surface  216 . 
     A right side surface  219  is disposed between the side groove lower surface  218  of the side groove  250  and the light reflecting patterned surface  210 . A left side surface  215  is disposed between the light emitting surface  216  and the top groove upper surface  214  of the top groove  270 . A bottom side surface  211  is disposed on a left corner of the light reflecting patterned surface  210 . An angled side surface  212  is disposed between the bottom side surface  211  and the top groove lower surface  213 . 
     Refer to  FIG. 5B , which is a cross-sectional view drawing illustrating a light guide of a coverless linear light source according to an embodiment of the present invention. 
     In the embodiment illustrated in  FIG. 5B  the light guide  200  comprises a left groove  280  disposed on the light guide  200  where the angled side surface ( 212   FIG. 5A ) was positioned. The left groove  280  comprises a left groove upper surface  221  and a left groove lower surface  212 . The left groove upper surface contacts the top groove lower surface  213  of the top groove  270 . The left groove lower surface contacts the left corner of the bottom side surface  211 . 
     Refer to  FIG. 6A  and refer to  FIG. 6B , which is a cross-sectional drawing illustrating light paths of the light guide with light reflecting patterned surface according to an embodiment of the present invention, and to  FIG. 6C , which is a cross-sectional drawing illustrating emitted light paths of the light guide according to an embodiment of the present invention. 
     When power is applied by the printed circuit board to the conductive pins  320 , which are electrically connected to the LEDs  310 , the LEDs  310  illuminate and emit light into the light receiving end of the light guide  200 . The light travels or propagates through the light guide  200  and is reflected by the light reflecting patterned surface  210  towards the light emitting surface  216  of the light guide  210 . Some of the light can be reflected by other sides, for example, the bottom side surface, the right side surface, the left side surface, the angled side surface, the top groove, the side groove, or the left groove prior to being reflected by the light reflecting patterned surface  210 . 
     The light reflected by the light reflecting patterned surface  210  towards the light emitting surface  216  exits the light guide via the light emitting surface  216 . 
     The light paths of the emitted light of the light guide  200  travel in a variety of angles away from the light emitting surface  216 . In an embodiment of the present invention as illustrated in  FIG. 6C  the emitted light shines in a range of, for example, 105 degrees. This field of illumination allows for uniform illumination of the target object to be captured. 
     Refer to  FIG. 7A-7D , which are drawings illustrating a coverless linear light source, lens array, main housing, and printed circuit board according to an embodiment of the present invention. 
     The sub-module for a scanner comprises main housing  500 , a printed circuit board (PCB)  600 , a lens array  400 , and the coverless linear light source  100 . 
     The PCB  600  comprises circuitry and electronic devices for controlling the electrical components of the sub-module. The lens array  400  focuses light reflected off of the target object and passes the focused light to sensors below the lens array  400  for capturing an image of the target object. 
     The main housing  500  holds the components of the sub-module together. The main housing  500  comprises a top clip  510 , a side clip  520 , a light guide cavity  530 , and a hooded bracket cavity  540  all disposed on a top surface of the main housing  500 . The top clip  510  and the side clip  520  are disposed on opposite sides of the light guide cavity  530 . The hooded bracket cavity  540  is disposed on an end of the light guide cavity  530 . 
     To assemble the sub-module for the scanner, the PCB  600  is inserted into the bottom of the main housing  500  and the lens array  400  is inserted into a top area of the main housing  500 . 
     The coverless linear light source  100  is inserted into the light guide cavity  530  and the hooded bracket cavity  540  with the elongated polygonal transparent section of the light guide  200  inserted into the light guide cavity  530  and the hooded bracket  220  of the light guide  200  inserted into the hooded bracket cavity  540 . 
     The conductive pins  320  of the LED module extend through PCB holes  601  in the PCB  600  and are electrically connected to conductive traces on the PCB  600 . 
     When the light guide  200  is inserted into the light guide cavity  530 , the side clips  520  of the main housing  500  enter the side groove  250  of the light guide  200  and grasp the side groove lower surface. Also, the top clips  510  of the main housing  500  grasp and apply pressure against the top groove lower surface of the top groove  270 . The top clips  510  apply pressure against the top groove lower surface to push the light guide  200  against the side clips  520  and maintain the side clips  520  in the side groove  250 . In this way, the coverless linear light source  100  is securely held in the main housing. Additionally, if required, the coverless linear light source  100  can be removed from the main housing  500  by applying pressure against the top clips  510  to release the side clips  520  from the side groove  250 . 
     In operation the PCB  600  provides power to the conductive pins  320  of the LED module which turns on the LEDs. The LEDs emit light into the hood back of the hooded bracket which is the light receiving end of the light guide  200 . The light reflects off of the light reflecting patterned surface  210  of the light guide  200  and exits the light emitting surface of the light guide  200 . The light illuminates a target object and is reflected to the lens array  400  which focuses the light for sensors to capture an image of the target object. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the invention and its equivalent.