Abstract:
A combination red dot sight (reflex sight) and electronic range indicator displayed in a sighting element. The sighting element is housed in a body which includes lens elements and a light source for the red dot sight as well as an optical display for the range indicator. A processor for the red dot sight and the range indicator are housed in a frame. A user interface includes indicia for varying the intensity of the light source for the red dot sight as well as activate the range indicator. Alternately, the range indicator may be activated by a button positioned remotely, such as on the firearm or bow and may be wired to the range indicator circuit or communicate via wireless transmission. An emitting lens and a receiving lens are optically connected via a range finding circuit to the processor.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/687,501 entitled “COMBINATION RED DOT SIGHT AND RANGE FINDER APPARATUS” filed Jun. 3, 2005. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to sighting devices for bows and firearms. 
     BACKGROUND OF THE INVENTION 
     The use of sighting devices by hunters and marksmen has been known for centuries. Hunters and marksmen have long used sighting devices in order to accurately direct a projectile from a bow, pistol, rifle, or shotgun. Such sighting devices have evolved from simple mechanical devices which were aligned to the target to optical scopes with precision lenses and laser pointing devices. 
     A reflex sight (or red dot sight) is a sighting device which can be affixed to a bow, pistol, rifle, or shotgun, to assist in aligning the projectile with the intended target. In such devices, a dot of light, (traditionally red but other colors such as green are also available) is projected from a light sources (such as an LED) to a lens which is visible to the shooter who aligns the dot on the intended target. The dot is calibrated such that its alignment with the target also aligns the projected to the intended target. Such devices are commonly adjustable for distance (range), windage, and intensity (to accommodate various light conditions). However, as it is apparent, in order to adjust the sighting device for the proper range, one must first know the actual range to the target. 
     In order to determine range, many different types of range finding devices are known in the art. The presently most accurate type of devices are the electronic range finding devices. Electronic range finding devices produce a signal, most commonly a very fast pulse of laser light, directed at the target. A portion of the signal is reflected back toward the device which is then directed toward a receiving lens and a receiver. Microprocessor technology containing a high speed clock is used to calculate the distance (range) by measuring the time required for each pulse to travel from the device and back to the receiver. 
     At present, both the described sighting devices and range finding devices are separate units which must each be carried by the hunter/marksman. In other words, hunters and marksmen using a red dot sight (reflex sight) on their bows, pistols, rifles, or shotguns must also use another device for range finding to gauge the distance to their intended target. In the case of most hunting situations, when time is spent determining the distance to the game with one device and then additional time spent getting ready with the bow or firearm, often the game has moved thus negating the advantage of knowing the target&#39;s distance. A need, therefore, exists for an inclusive combination device which includes a red dot sight and an electronic range finding device in one unit. 
     SUMMARY OF THE INVENTION 
     The present invention includes a combination of a red dot sight (reflex sight) and range finding (or indicator) apparatus. The present invention combines a range indicator with a red dot sight in a single sighting element. A range indicator display is optically visible to the user in the same sighting element as the red dot sight. In this way, the user does not have to divert his or her line of sight from the red dot sight in order to obtain the range to the target and vice versa. The present invention further combines an electronic range finding device and the red dot sighting device into a single unit which is capable of mounting on a bow, pistol, rifle, or shotgun. By having a combination red dot sight and electronic range indicator apparatus in a single unit, a hunter or marksman can quickly determine the distance (range) to the target and make an accurate shot thereto. In one preferred embodiment, the magnification of the sight is relatively low (such as 1×) such that the user can leave both eyes open while using the sight and thus maintain normal depth perception. For purposes of the present invention the term “bioptic” describes a sight or scope which allows the user to leave both eyes open to maintain normal depth perception and full field of view while using the sight. 
     The combination sighting device of the present invention could have a single rectical (red dot aiming point) or multiple changeable recticals and could have the distance to target displayed within the sight or displayed externally. The electronic range finder function could be activated in the combination of the present invention with a push button located on the body of the combination device or have an external push button which could be either connected to the combination device via a cord or via a remote operation such that the push button could be attached to the bow, pistol, rifle, or shotgun in any convenient location. 
     Accordingly, it is an object of the present invention to provide a combination of a red dot sight for sighting a target in an apparatus for determining the range to the target in a single unit. Other objects would be apparent from the attached drawings, the specification and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a preferred embodiment of the combination electronic range finder apparatus and red dot sight of the present invention affixed to a pistol. 
         FIG. 2  depicts a preferred embodiment of the combination electronic range finder apparatus and red dot sight of the present invention affixed to a shotgun. 
         FIG. 3  is a partial side view of the combination red dot sight and electronic range finder apparatus of the present invention illustrating the red dot sight function. 
         FIG. 4  is an electrical diagram depicting one preferred embodiment of the electronic range finder device of the combination red dot sight and electronic range finder apparatus of the present invention. 
         FIG. 5  is a side view of the combination red dot sight and electronic range finder. 
         FIG. 6  is a rear view of the combination red dot sight and electronic range finder. 
         FIG. 7  is a top view of the combination red dot sight and electronic range finder as seen from section  7 - 7  of  FIG. 6   
         FIG. 8  provides a perspective view of the combination red dot sight and electronic range finder attached to a pistol. 
         FIG. 9  is a block diagram of a preferred embodiment of a range finder as used on the sight of  FIG. 7 . 
         FIG. 10  is a block diagram of a preferred embodiment of the circuitry employed in the sight of  FIG. 7 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before explaining the present invention in detail, it is important to understand that the invention is not limited in its application to the details of the embodiments and steps described herein. The invention is capable of other embodiments and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation. 
     The present invention relates to a combination of an electronic range finding device and a red dot sight (reflex sight) in one unit.  FIG. 1  depicts the combination electronic range finding and red dot sighting device  10  affixed to a pistol  20 . As shown, combined electronic range finding and red dot sighting device  10  is affixed to pistol  20  in lieu of the stock sight  30 A and  30 B so that the shooter can look through device  10  in a normal manner. 
     Combination electronic range finding device and red dot sighting device  10  includes a body  40  and a frame  50 . The optics for device  10  are housed within body  40  and the electronics within frame  50  (with the exception of an emitting lens described below). Frame  50  is mounted to pistol  20  in a known manner. 
       FIG. 2  depicts an alternate embodiment combination electronic range finder and red dot sight  100  mounted to a shotgun  102 . The device of the present invention may also be mounted on a rifle or a bow (not shown). 
     The red dot sight apparatus of combination device  10  shall next be described.  FIG. 3  is a partial cutaway view depicting body  40  of combination device  10  (of  FIG. 1 ) for the purpose of illustrating the red dot sighting device. Body  40  comprises, generally a cylindrical tube which houses lenses  60  and  70  and a light source  80 . Light source  80  in the preferred embodiment is a light emitting diode which emits a red light that is projected toward concave lens  60 . Lens  60  includes a thin metallic coating that reflects red light but transmits other colors freely therethrough. In operation, the red light emitted from light source  80  is reflected by lens  60  and directed back toward the shooter&#39;s eye through lens  70 . To the shooter, the dot appears to be projected upon the target and is calibrated so as to be aligned with the direction of the projectile directed toward the target. This alignment can be adjusted for elevation and windage by moving the body horizontally or vertically. This adjustment may be performed either manually with screws applied to coil springs in a known manner, or electronically, by the use of adjustments  90  for windage and  92  for elevation ( FIG. 6 ). The combination device of the present invention could have a single rectical (red dot/aiming point) or multiple changeable recticals. Further, the elevation alignment may occur automatically based on the range provided by the range finder. 
     The distance between lens  60  and lens  70  can be adjusted so as to account for eyesight imperfections of the shooter in order to provide an accurate sighting device. It should also be understood that the light source could be any other acceptable color, such as green and it is not limited to the red described above with regard to the preferred embodiment. However, it is understood that the coating on lens  60  would have to be changed to accommodate the color of light emitted from the light source. 
     With reference to  FIGS. 5 ,  6 , and  8 , sight/range finder combination  10  further includes a battery holder  94  having a removable battery cover  96  for housing a battery to supply electrical power for operation of the device. In one preferred embodiment, tube  88  houses a detector  226  ( FIG. 9 ) for the range finding circuit (as discussed in more detail hereinbelow) and tube  98  houses the corresponding emitter  224 . It should be noted that the roles may be reversed, i.e. tube  88  housing the emitter and tube  98  housing the detector or one, or both, of the emitter and detector may be housed within the body  40  of sight  10 . 
     The electronic range finding aspect of the combination device of the present invention shall next be described. Turning to  FIG. 10 , a preferred embodiment of an electronic range finder  200  includes: a processor  210 ; a range finding circuit  212 ; and a display  214 . For the purposes of the present invention, the term “processor” is to be broadly construed to include any circuitry which is capable of coordinating the functions of the range finder circuit  212 , the display  214 , and the user interface  260  ( FIG. 7 ) which is described in more detail hereinbelow. By way of example and not limitation, a processor may comprise a microprocessor, microcontroller, programmable gate array, field programmable gate array, ASIC semiconductor, or even discrete logic. 
     With further reference to  FIG. 9 , a preferred embodiment of range finder  212  includes: a pulse generator or trigger  220 ; a timer  222  which is initiated by pulse generator  220 ; a laser, or LED, emitter  224  which generates a pulse of light corresponding to the output of pulse generator  220 ; a phototransistor, photodiode, or like device,  226  which receives the pulse of light after it is reflected off of a target; and output  228 . When a reflected pulse is received at detector  226 , timer  222  is stopped. The time measured at timer  222  is representative of the distance between the range finder and the target. By way of example and not limitation, since light travels at roughly 300 million meters per second, if timer  222  is counts at a rate of 150 MHz, each count is roughly equal to one meter (in light of the fact that the pulse of light must traverse the distance twice for the round trip). Upon receipt of the reflected pulse, the count is presented at output  228  for use by processor  210 . As will be apparent to those skilled in the art, delay may be introduced by emitter  224 , detector  226 , and even by timer  222 . If such delays create objectionable error, the delay may be subtracted from the time determined by timer  222  either within timer  222 , within processor  210 , or even within display  214 . 
     With further reference to  FIG. 4 , by way of further example and not by way of limitation, a more specific circuit diagram for the electronic range finding feature  200  is depicted. 
     As shown, an optical pulse generator  230  produces a pulse of laser light which is carried through fiber coupling  232  to an emitter  234 . The pulse of laser light is produced from emitter  234  through a lens  236  and directed toward a target  250 . A portion of the pulse is reflected from the target back to a lens  238  and a receiver  240 . In the device of the preferred embodiment of  FIG. 1 , lens  238  is the same lens as concave lens  60  described above and depicted in  FIG. 3  while lens  240  is positioned within frame  50  beneath body  40 . 
     Once the pulse is received by the receiver, microcontroller  242  calculates the distance to the target through the use of a high speed clock contained therein by measuring the time taken for the pulse to travel from the emitter to the target and back to the receiver. 
     Pulses of laser light produced from the electronic range finding unit may be continuously produced in a repetitive manner. However, in the preferred embodiment, in order to preserve significant power in the power supply which powers the device, the pulse is selectively emitted by the shooter through the use of a push button as part of the user interface of  FIG. 7 . 
     With reference to  FIG. 7 , wherein is shown a preferred user interface  260  for the range finder system  200 , user interface  260  includes: a power on/off button  262  for starting and stopping operation of the range finder  200 ; a mode push button  264  for selecting an operational mode of range finder  200 ; a range button  266  for initiating a range finding pulse from the range finder  200 ; up arrow button  268  for increasing the intensity of the red dot in the scope and down arrow button  270  for decreasing the intensity of the red dot; and a series of indicators  272 - 286  for indicating the various operational modes of the sight/range finder combination. 
     In operation, the user presses the power button one time to turn the red dot sight and range finder on. In a preferred embodiment, the range finder may include a photo sensitive detector to detect the amount of ambient light and set the intensity of the red dot emitter accordingly. Initially indicator  272  will illuminate to indicate power is on, indicator  274  will illuminate to indicate that the red dot is in auto brightness mode, and  278  will illuminate to indicate the range finder is in standard mode. 
     If the user presses either the up arrow  262  or the down arrow  270  the red dot intensity will increase or decrease, respectively. When the user adjusts the red dot intensity, indicator  274  will be extinguished to indicate that the sight is no longer in auto brightness mode and indicator  276  will be illuminated to indicate the sight is in manual brightness mode. In one preferred embodiment there are 20 intensity steps of the red dot, the bottom three steps being visible only with night vision goggles. Preferably the user can express to maximum brightness by depressing up arrow  268  for three seconds or to minimum brightness by depressing down arrow  270  for three seconds. Auto mode may be resumed by simultaneously pressing arrows  268  and  270  for two seconds. Indicators  274  and  276  will illuminate appropriately. 
     In another preferred mode of operation the condition of the battery which powers the sight may be test by depressing button  264  three times succession. Battery status indicator  286  will flash once if the battery is to 25% of its charge or less, twice if the battery is between 25% and 50% of full charge, tree times if the battery is between 50% and 75%, and four times if the battery condition is above 75% of its maximum charge. 
     If button  266  is depressed for three seconds, indicator  280  will illuminate to indicate that the range finder is in the scan mode. In the scan mode, the range finder generates range finding pulses in a repetitive manner and updates the display with each new pulse. 
     Button  264  may be depressed to change the range finder between yards and meters. Indicator  282  is illuminated to indicate that the unit of measure for the range finder display is yards and extinguished to indicate that the unit of measure for the range finder display is meters. 
     Button  262  may be pressed twice in succession to change the range finder to a mode where distances greater than 150 yards (or meters) may be measured. Indicator  284  is illuminated to indicate that the range finder is in such a mode. Pressing and holding button  262  will turn the power off to the sight and range finder. Alternatively, the sight and range finder will automatically turn off two hours after the last button is pressed. 
     Optionally, an external button may be used in lieu of button  266  to initiate ranging. This button may be connected by a cord or wirelessly, and may be hand held or attached to a gun to improve the ergonomics for a particular user. 
     While preferred embodiments of the present invention have been described with reference to a pulsed laser range finder, the invention is not so limited. As will be apparent to those skilled in the art, a number of range finding techniques are well known, any one of which may be appropriate for use with the present invention depending on the type of target, the range over which targeting is planned, and the resolution which the shooter desires from the range finder. By way of example and not limitation, other known range finding techniques include: ultrasonic ranging; off-axis light emission where the distance off-axis from the reflected light is representative of the distance to the target; a modulated laser where the phase angle of the modulation of the reflected light relative to the source light is indicative of the distance to the target; and the like. 
     Accordingly, a novel combination electronic range finding device and red dot is described. 
     Thus, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those skilled in the art. Such changes and modifications are encompassed within the spirit of this invention as defined by the appended claims.