as required , detailed embodiments of the present invention are disclosed herein ; however , it is to be understood that the disclosed embodiments are merely exemplary of the invention , which may be embodied in various forms . therefore , specific structural and functional details disclosed herein are not to be interpreted as limiting , but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure . a detailed description of the different configurations of lasers , mirrors , diodes , gain control systems , as well as the different power controls located inside the mph will now be discussed . a detailed description of the mph will then follow . the present invention can be arranged as either a binary system or grayscale system . in a grayscale system , the 740 nm signal received by the pd is simply echoed and re - transmitted by the visible 638 nm laser 201 . in this manner , various levels of intensity can be shown . accordingly , the image of a vein may vary in intensity as a function of the magnitude of signal received . in a binary system , the projected image is either on or off . to determine whether the projected image should be on or off , a comparator with a trip point is placed after the photodiode . if the signal crosses the trip point the output laser 638 nm 201 is turned on and vice versa . there are several ways to set the trip point . for example , a user dial or press button ( or any other input means ) could be placed on the device , and the user can manually adjust the trip point ( essentially making the device more or less sensitive ). the vein enhancer of the present invention , implements at least two lasers , 201 and 202 , contained in the same housing , as seen in fig1 , which makes for easier operability and maintainability , that is , less chance of losing one of the devices , as in citied prior art . in addition , the present invention has : improved beam combiner glass , higher power ir , improved mirrors , smaller photo diode setup ; used for collection optics , cables for electronic hook - up , agc , and a microprocessor ; used for mirror control and laser calibration . with all the aforementioned enhancements many significant improvements in the vein enhancement art can be obtained , one area in particular , is safety . laser projection devices have agency regulations dictating power output limitations . generally , the power of a laser is limited to a threshold level so as to protect the user &# 39 ; s eye from injury . if , however , the user &# 39 ; s eye is prevented from getting too close to the laser , then the power of the laser may be increased . prior art in the past have implemented physical barriers that are incorporated into the design of the laser . these barriers help prevent the user &# 39 ; s eye from getting too close to the origin of the laser projections , thus laser power may be increased . for example , previous prior art have used protruding bars ( similar to those used in football helmets ) that are placed in the direction of the optical path . this prevents the user from placing an eye too close to the laser . in the present invention , signal processing can be utilized to control the power output . for example , in one embodiment the acquired image pattern is stored in a computer memory . the image is then processed to determine whether veins are present , and only upon confirmation of the vein being present is the image projected . in this manner , the visible laser will not be turned on if the laser is in the direction of the user . in another embodiment , the power of the 740 nm laser 202 can be set to an initially low setting . once the laser detects a vein , the power of the 740 nm laser 202 can be increased and the 638 nm laser 201 turned on . in yet another embodiment , the laser can be configured so that the laser will only be activated when a proximity sensor 220 determines the surface , or eye of a user . the interface of proximity sensor 220 and the main electronics 260 may be seen in fig7 . although the vein enhancer of the present invention may be configured to operate in a multitude of ways , it includes at least one laser , one photo diode and at least one mirror . depending on the desired output and / or operating costs additional components may be incorporated into the design of the present invention . two embodiments that have been found useful in the vein enhancement art will now be discussed , a discussion of alternative embodiments will follow . both embodiments implement 2 photo diodes ( hereinafter pds ) and at least two lasers . in addition , depending on the desired result , there can be a polarization film 270 , as seen in fig8 , placed on the pd , thus further reducing specular reflection . this works particularly well with embodiments of the present invention which include a 740 nm laser and a broad spectrum pd . regarding the first embodiment , it is necessary to co - axially align the two lasers . co - axially aligning the two lasers can be achieved in a multitude of ways . two methods that have proven to be effective include implementing , either , a dielectric mirror or a polarizer . the first configuration includes a first laser calibrated to transmit light in the infrared ( hereinafter if ) spectrum , that is 740 nm , and a second laser calibrated to transmit a light in the red color spectrum , that is ≈ 638 nm . the first configuration , as mentioned above , implements a hot mirror 204 coated with a dichroic substance , which separates and directs the light onto two separate diodes . this system allows the visible and ir laser reflections in real - time without the use of a memory chip . with this embodiment the 638 nm laser 201 is oriented behind the dielectric mirror . the dielectric mirror is selected so that the 638 nm laser light passed through but the 740 nm is reflected . the 740 nm laser is aimed at the front of the dielectric mirror and is angled and aimed so that the refection of the 740 nm laser is coaxial with the 638 nm laser passing through the dielectric . in the second configuration , the 638 nm laser is polarized in a first orientation and is placed behind the polarized element . the polarized element is selected so that the first polarized orientation passes through , but the second polarized angle is reflected . the 740 nm is polarized to the second polarized angle and is aimed at the front of the polarized element and is angled and aimed so that the reflection of the 740 nm laser is coaxial with the 638 nm laser passing through the polarized element . regarding the second embodiment , the two lasers are multiplexed . it has been noted that the signal received by the 740 nm pd of the present invention is representative of both the veins and the surface topology of the patient . put another way , the surface of the patient affects the reflected signal . this is not desirable , in that the area of interest is the veins of the patient and not the surface topology of the patient . thus , by using a second ph for receiving the 630 nm reflected signal , the 630 nm signal ( the topology ) can be subtracted from the 740 nm signal ( topology + veins ) yielding a signal that is solely the veins ( topology + veins − topology = veins ). in this system the microprocessor 250 or state machine circuit , as seen in fig8 , can record the reflection from the visible laser and the ir laser can be turned on for one frame , every other frame , or every other scan line . hence , a new signal would contain a combined laser reflection . the new signal would then be subtracted from the visible signal only , thus leaving the if signal . the advantage here is that the visible laser does not have to be turned off , which has the benefit of not attenuating the visible light while reading the if laser reflection . other configurations may include a multi laser array and a led . first , the multi laser array will be discussed . in this embodiment a linear array of visible lasers and a linear array of a lasers may replace the single visible laser and single ir laser . with this type of configuration , the linear array of visible lasers and linear array of ir lasers are reflected off a single mirror that oscillates . an advantage of this laser configuration is twofold . first , the mirrors being implemented are less complex . second , the collection means of the reflected ir light can be obtained by a retro collective mirror . a retro collective mirror is a mirror that has a field of view that corresponds to the array of lasers and moves in concert with the movement of the array of lasers . a characteristic that makes the retro collective mirror ideal for this configuration is the improved signal to noise ratio ( snr ). evident from the above disclosure , it may be desired to implement one pd 207 , as can be seen in fig1 and 8 . in the embodiments that implement one pd , that pd is usually responsive to the 740 nm wavelength but not the 638 nm wavelength . in this manner both lasers can be on at the same time without having the 638 laser couple into the pd . however , the same results can also be achieved via opposite modulation . in another embodiment the , 638 nm and 740 nm , lasers may be modulated oppositely . in this embodiment the pd will also be responsive to the , 638 nm and 740 nnm , laser , but the lasers will be modulated in opposite directions . more specifically , both the lasers can be pulsed on and off at high rates without affecting the apparent quality of the image ( 638 nm projection ), or the quality of the acquired image ( the reflections of the 740 nm laser ). by synchronizing the two lasers so that the modulation is in opposite directions ( the 638 nm on and 740 nm off , followed by , 638 nm off and 740 nm on ), the image acquisition circuits ( pd and amplifiers , if implemented ) can be arranged to ignore signals when the 638 nm laser is on . in this embodiment , the visible 638 nm laser does not interfere at all with the image acquisition apparatus . all the aforementioned embodiments implemented either single or multiple lasers . it shall be disclosed now that in all aforementioned embodiments a tightly focused led may replace the lasers . it should be mentioned that this embodiment has limited use in that the resulting projection will not be a collimated laser beam and it will diverge over distance . however , in those limited instances where the distance from the device to the surface is closely held , an appropriate focusing can be obtained . the present invention also includes a means for gain control . two possible methods of adjusting the gain of the system are possible . a prior art method of adjusting gain is to fix the 740 nm laser output and to adjust the gain of the photo detection circuitry so as to get an appropriate signal ( not too low and not saturated ). however , there is complexity in such an adjustment due to the speed requirements of the photo detector gain adjustment . an alternative approach , as in the present invention , is to fix the gain of the photo detection circuitry , as in prior art , but adjust the power output of the 740 nm laser so that an appropriate signal is outputted from the photo detection circuitry ( once again not too low , but not saturated ). it is much easier to design circuits that adjust the 740 nm lasers due to the extremely high modulation bandwidth of the lasers . for example , the 740 nm laser may be modulated as needed to prevent saturation of the photo detector circuitry . alternatively , the amplitude of the 740 nm laser can be adjusted to provide appropriate signal out of the photo detection circuitry . throughout all the embodiments previously discussed , adjusting the power of either the 638 nm laser , or 740 nm laser , can be achieved by either adjusting the current to the lasers , or alternatively , modulating the lasers on and off at a rapid rate . regarding modulation , depending upon the duty cycle ( pulse - width - modulation ), the average laser intensity will be changed . with respect to the visible 638 nm laser , the human eye will integrate the signal and , provided the frequency of the pwm is faster than the eye integration time , the laser will appear dimmer as the on cycle time decreases , and vice versa . the power of the 740 nm laser may be also be adjusted by pwm , this modulation will have the same effect upon the received signal as if the current was decreased to the laser . the mph will now be described . fig2 shows a prior art scanning laser - based camera ( hereinafter slbc ) 170 of microvision , inc . fig1 is taken from microvision &# 39 ; s website : ( http :// www . microvision . com / technology / imaging_works . html ) dated jan . 7 , 2006 , herein incorporated by reference . the slbc 170 includes a laser source 171 which gets reflected off mirror 172 to a mems scanner 173 . the mems scanner 173 has a reflective surface that can be oscillated in both the x and y axis . the oscillation of the mems scanner 173 is controlled by electronics ( not shown ) so that the reflected laser beam is moved in a raster pattern . to create a color camera , the laser source is a combination of a red , green and blue laser , thereby forming the color white . three photodetectors , one responsive to red 175 r , one responsive to blue 175 b , and one responsive to green 175 g are positioned on the slbc 170 and receive the rastered laser light reflected off object 176 . the output of the photodetectors 175 r , 175 b , and 175 b provide an analog rastered image representative of the object 176 . the outputs of the photodetectors are converted from an analog signal to a digital signal by d / a converters ( not shown ). a controller ( not shown ) determines the instantaneous rastered laser light position and converts that to an appropriate pixel location . the controller then writes the digitized rgb values to an appropriate pixel memory location . by repeating this step for each pixel location , a digitized version of the object is stored in memory . each raster sweep of the field of view 4 results in a new image being stored . by sweeping at video rates , video images can be captured . a publication in laser focus world . december 2004 . authored by chris wiklot entitled “ display technology spawns laser camera ” , herein incorporated by reference , describes the slbc of fig2 in even greater detail . drawing one &# 39 ; s attention to fig4 - 6 are three different modes of operation that the present invention may be used , a brief description of each mode of operation follows . a first mode of operation which will be referred to hereinafter as an “ alternating frame mode ” ( afm ) may be seen in fig4 . in the afm mode , an electronic block 192 for driving the mems driver and for sensing the position of the raster scanner is provided 192 . this block generates the signals required to drive the mems scanner 173 in a raster pattern , and also determines the exact instantaneous location of the mems scanner and communicates this information to an image memory 191 . this electronic block 192 also generates output signals and indicates whether the current frame ( a frame is a complete raster of the field of view ) is an odd number frame 1 or an even number frame 2 ( essentially the two signals are opposite and switch polarity every other frame ). the operation is as follows . the mems 173 is driven in a raster pattern . the first full frame after achieving a stable raster pattern will be identified as an odd number frame and the laser driver 195 for the 740 nm laser 183 is turned on for the entire frame . during this time the laser drive 194 for the 630 nm laser is turned off . the light from the 740 nm is absorbed by the veins in a patient &# 39 ; s body and reflected by the skin of the patient , thus forming a contrasted image that is then sensed and converted into an analog signal by 740 nm photodetector 182 . the analog signal is then passed through an a / d converter 190 which outputs a digital representation to image memory 191 . image memory 191 also receives instantaneous position information from the electronic block 192 , and based upon such information , the digital representation is stored in a memory location corresponding to a particular pixel . this is repeated for each pixel within the odd frame . upon completion of the odd frame , the image memory contains the image of the veins within the field of view of the mph . during the even number frame , the laser driver 195 to the 740 nm laser is turned off . the data in the image memory 191 is read out as a function of the instantaneous position information provide by the electronic block 192 and provide to a d / a converter 193 which outputs an analog signal to laser drive 194 which drives the 630 nm laser . in this manner , the image that was stored in the odd number frame is projected by the 630 nm laser 180 in the even number frame . in this manner , the veins that are in the field of view become visible to the practitioner . a second mode of operation is shown in fig5 . this mode shall be referred to hereinafter as the “ dual buffer mode ” ( dbm ). in the dbm , a second image memory called image memory two 196 is added . in the dbm , the laser driver to the 740 nm laser is turned on for every frame and in each frame the image of the veins is captured and stored in image memory 191 exactly as described previously in the afm mode . however , in this case the electronic block 192 provides an end of frame indication to both image memory two 196 and image memory 191 which causes the entire image stored in the image memory 191 to be transferred to image memory two 196 during the blanking time of the raster scan ( the time after the raster scan is completed but before the next raster scan starts ). during the next frame , the contents of image memory two 196 is then projected by the 630 nm laser onto the field of view . in this manner , the visible image projected is always on frame behind the actual image captured . provided the frame rate is fast enough , this delay should not be apparent to the practitioner . frame rates in excess of 30 frames per second can easily be achieved with the mems scanner provided herein . the dbm mode is advantaged as compared to the afm in that the visible laser is on every frame , and therefore is twice as bright . however , the afm mode is advantaged in that it only requires a single memory buffer and therefore is more cost effective than the dbm mode . a third mode of operation is illustrated in fig6 . this mode shall be referred to hereinafter as the “ real time mode ” ( rtm ). in the rtm the mems 173 is driven in a raster pattern by a mems driver 210 . the laser driver 195 to the 740 nm laser is turned on all the time . the reflected light is received by the 740 nm photodetector 182 and the analog signal produced is connected to the laser driver 194 for the 630 nm laser 180 . in this manner the red laser 180 projects nearly instantaneously the signal that is being received by the photodetector 182 . the only delay is dictated by the speed of the photodetector and the laser drive 194 circuitry . accordingly , there is no need for an image memory buffer and associated d / a converters and a / d converters . further , since the image is never stored , there is no requirement to sense the instantaneous position of the laser for the purpose of clocking the image into memory or for projecting the visible image . in fact , in this rtm , the raster pattern does not need to be as steady and repeatable as that of the other modes , thereby possibly decreasing the complexity and cost of the mems and associated drive circuitry . drawing one &# 39 ; s attention now to fig1 is a preferred embodiment 200 of a mph the present invention . this embodiment replaces the mems scanner with a two dimensional mirror . one such two dimensional mirror is provided by fraunhofer ipms . in a press release dated jan . 3 , 2005 they described a two dimensional mirror as follows : “ projection devices based on laser scanning are a very interesting alternative to matrix displays . a modulated laser and a deflection unit are necessary . using micro scanning mirrors for implementing the laser beam deflection in a projection device has many advantages . in particular , micro scanning mirrors , which operate resonantly in both directions , enable the development of systems with very small size , high deflection angles with low voltage and low power consumption . the presented demonstrator uses a commercial laser module and a 2d micro scanning mirror operated with deflection frequencies of 9 . 4 khz and 1 . 4 khz . the device uses both axes to perform a sinusoidal oscillation , which causes a beam trajectory that describes a lissajous pattern with high density , instead of the usually implemented linear scanning . therefore , mirrors with low ratio of horizontal and vertical deflection frequency can be used . this kind of micro scanning mirrors can be fabricated easily and cost effective . the control circuit is developed with an fpga and provides a resolution of 256 . times . 256 monochromatic pixels . programmable counters are used for generating the mirror driving signals and for determining the beam position . mirror excitation and image synchronization work without feedback loop . this means , no complicated optical or electronic synchronization techniques are needed . this simplifies micro scanning mirror and control circuit and enables low cost production . applications of the projection device are displays , laser marking and laser exposure .” in the rtm of fig6 , the two - dimensional mirror of fraunhofer ipms creates a lissajous pattern with high density instead of the raster pattern . the visible laser will simply follow nearly instantaneously the image detected by the 740 nm laser detector . the mph 200 may also include two laser sources . a first laser source 201 having a wavelength in the visible light spectrum , preferably ≈ 632 nm , and a second laser 202 having a wavelength preferably ≈ 740 nm , that is ir . lasers 201 and 202 may be any suitable lasers known in the art . combiner 203 may have at least one bounce mirror . in a preferred embodiment there can be two bounce mirrors , 203 a and 203 b . in the preferred embodiment combiner 203 may also include a dielectric coated mirror 204 . mirror 204 may be any suitable type of dielectric coated mirror known in the available art . in a preferred embodiment mirror 204 was coated with a material that reflects ir and transmits other wavelengths . as mentioned above , the embodiment as depicted in fig1 replaces the mems scanner with a two dimensional scanning mirror 205 , such as the type provided by fraunhofer ipms . with this embodiment there can also be a collection mirror 206 , and at least one pd 207 . in normal operation , the embodiment as depicted in fig1 operates as previously discussed , that is , in any of the three operating modes ; however , it performs optimally in rtm . in yet another embodiment the lasers can be multiplexed , in which case the visible laser would not have to be turned off . in this embodiment all components would function in a similar manner as previously mentioned embodiments . however , the microprocessor or state machine 250 in this embodiment , as seen in fig7 , can record the reflection of the visible laser 201 and then the ir laser 202 can be turned on for any interval time duration , and combined with the visible laser . thus , the resultant beam 240 would be a combination of both lasers . beam 240 would be then subtracted from the previously recorded visible laser . the advantage here is that the projected visible laser would not be reduced by turning off the visible laser to read the infrared laser reflection . in another embodiment of the present invention there can be what is known in the art as a “ hot mirror ”. mirror 206 is preferably coated with a dichroic coating . this acts as a beam splitter . in normal operation mirror 206 will direct the light onto two separate pds . with this type of embodiment all other previously mentioned components may operate in the same manner . in normal operation laser 202 will transmit ir light 220 which will bounce off of bounce mirror 203 a . at which time laser 202 will begin to transmit light 221 at 632 nm . light 221 will pass through dielectric coated mirror 204 and light 220 will reflect of mirror 204 , resulting in a beam of light 222 that is a combination of both lights , as seen in fig1 . beam 222 will then be reflected of bounce mirror 203 b . the angle at which beam 222 is reflected will depend on the angle at which bounce mirror 203 b is placed . this will be determined by the manufacturer &# 39 ; s design requirements . once reflected off bounce mirror 203 b beam 222 will be projected onto the area of interest , that is , the area where the vein is located , via two dimensional scanning - mirrors 205 . the projected beam 222 will then be collected by collection mirror 206 . after which , collected beam will then be passed through hot mirror 206 to separate and direct beam 222 onto two pds 207 . this embodiment compares the visible light and the ir laser reflections in real - time , without a memory chip . other embodiments may implement a mems scanner , as seen in fig3 , to perform the same function as the two dimensional mirrors . this will depend on economic as well as practicable considerations . furthermore , there can be any array of polarizing filters and / or infrared filters located between the collection mirror and the photodiode , as seen in fig8 . in the embodiments herein the visible light transmitted was a red laser . however , any visible color or combination of color could be transmitted . for example , three laser rgb could be utilized to transmit full color images onto the field of view . while in the embodiments herein a single two - dimensional mirror which moves in two axis was used for steering the beam , other beam steering arrangements could be used . for example , the outgoing laser beams can be bounced first off a one dimensional high speed scanning mirror and then off a second lower speed mirror scanning in the opposite direction . there are many other methods known to those skilled in the art for creating raster and other scanned laser patterns . while many of the embodiments described herein utilized vial holders with needles , there are many other medical procedures which need to view the veins . the invention is not intended to be limited to devices which attach to vial holders . as various changes could be made in the above constructions without departing from the scope of the invention , it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense . in the view above it will be seen that several objects of the invention are achieved and other advantageous results attained , as defined by the scope of the following claims .
the present invention is a miniature vein enhancer that includes a miniature projection head . the miniature projection head may be operated in one of three modes , afm , dbm , and rtm . the miniature projection head of the present invention projects an image of the veins of a patient , which aids the practitioner in pinpointing a vein for an intravenous drip , blood test , and the like . the miniature projection head may have a cavity for a power source or it may have a power source located in a body portion of the miniature vein enhancer . the miniature vein enhancer may be attached to one of several improved needle protectors , or the miniature vein enhancer may be attached to a body similar to a flashlight for hand held use . the miniature vein enhancer of the present invention may also be attached to a magnifying glass , a flat panel display , and the like .