US2501438A - Streak retinoscope - Google Patents

Description

March 2l, 1950 J. c. coPELAND sTREAx RETINoscoPE Filed March l1, 1947 I A 1 nr.

A T TORNE KS Patented Mar. 2l, 1950 UNITED STATES PATENT ,()FFICEv s'rnmnnnrmosoorn Jacob4 C. ;Copeland, Chicago,Il1. fAppiicanonr/iarchii, 1947, seria1N0-7sa751 (C1. :ss-)

.8. Claims.

This invention :relates 1 to varetinoscope, particularly a streakfretinoscope.

A streak uretinoscope has-,several differences when compared with other retinoscopes. For example, the projected light is -a -linear band `instead of circular-and ythe band or streak isvariable in width.y A second differenceis that the streak retinoscope scans and neutralizes the pupillary reflex along 4any 1 individual lmeridian of the eye' independently from all-otherfmer-idians. To obtain' the Y' full :advantages of `a streak retinoscope it .is, therefore, necessary to provide means for rotating the streakand-to provide meansfor adjusting the width :ofy thestreak. To obtain'a linear form 1of light in the ,retinoscope such as a streak va specially constructedlight bulb is used which incorporates a straightlament so thatV the streak oflight which is projected into the eye is an- 'exact image of the-iila ment in the bulb. In order tol rotate the streak it has ordinarily" been necessary to provide some means forrotating the lamp bulb. Itis-also necessary to provide .somel means 'for varying the width of the streak. This has ordinarily been done by providing an opticalsystemand by providing for longitudinal lmovement of'l the Vlamp bulb so that the width 'of thestreak 'would-de pend upon the relative position of the'bulb: with respect to the distancefrom'the optical system.

The old method ofrotating' the. bulb so that the streak can then be rotated is to 'provide some means between the'bulb and EtheV 'electrical' connection suchas,for example, sliding contacts (seemy Patents Nos. 1,648,013 and..1,804,151)1or an 'accumulation ofi wireslof a'u-length 'suicient to provide for twisting. The old method oflproviding for longitudinal movement of the bulb for changing the width of the: streakofili'ght also requires an accumulation offwires or some Ikind of sliding contact between *the vlight bulb'fand the source ofielectric current. 'Sliding contacts are -never entirely satisfactory. When twisted wires are placed between' the plug "and the light bulb, constant use of the instrument will 1 be wearing. upon the .wiresI land there is likelihood of 1a short circuit orclear break in the wire conneclons.

According tothe present invention'it has" been found .possible to construct; a streak retinoscope in which the streak can be'rotated and in which the width of lthe streak can be adjusted while at thev Sametime. securingV the advantages `-of a non-.rotating ,bulb in `Vfixed position. This is accomplished by providing L a s-gspheroprismatic y2 optical system which rrotatesy the image ,andy which varies the width-of theystreak.

With a nxed bulb it=has lalsobeen" found advantageous to employ, -an inclinationresponding switch which automatically causes the -bulb to light when thefinstrument is raised 'toan erect position and automatically turns -oi the light when the instrumentisf-placed ina horizontal position.

In the old type rstreak;f retinoscope-ithas also been customary -toprovide a -sleeve vattached to the bulb carrying deviceto-rotatethe bulbfwhich produces the.- streak-of light. A slot is provided in they tubular container tov A.per-mit rotation of the sleeve. In order jto not vunnecessarily weakenA the tubular container, the slot was not cut more than 180 so-thatthe amountyof rotation that could be given to` the bulb (and, therefore, the streakoflight) Wasi-limited to 180-1in the previous typeof .streakretinoscopes -By employing an optical` rotating device, such as a Dove prism, which-frotates the image two degrecs for everydegree-of rotation ofthe-optical system, the presentv invention provides-for a rotation of the image'` thev full 360 by employing a slot of only 180 in the tubular-container. yAl though there are only .-180 meridians in-a complete 360 circle,` in rotating the Y streakl through these 180 meridiansfonef-iindsthe 180- limiting factors effected by the slot to be Va source ofcousiderable annoyance.r When one vrequiresonly a few degrees of movement of the streak in a given quadrant andefinds that this movement Ais limited bythe slotfabackward rotation inexcess of is necessitated in order to observe the'desired meridian.V If, for. example, the streak were located atk meridian gl'fhorizontalpositioniandgcouldffnot-rotate clockwise one must then rotate-counter clockwise through 170 to reacha desired meridian of In the-present retinoscopaone need only-to rotate 1- thestreak 10. (or the'optical systemv?) .to ,obtain the 170 meridian.

vAn' object of this inventionis, to; construct.; a streak retinoscope-fin which-it5isnot necessary to rotateor move longitudinally lany oftheVA electrically connected parts `to obtain a rotation of the streak orto obtain Aa variationA in the width of the4 streak..`

VAnother `object of theinventionis .to construct a streak retinoscope with-anautomatically operated electrical,v switch which will automatically extinguish or v.turnoil ,the light bulb when-the instrument is placed in.. ka horizontal position. Usually the lightl bulbsv eniployedV in a streak retinoscope are specially constructed bulbs with a straight line filament and for this reason they are expensive. It is, therefore, important not to keep the bulbs lighted when they are not in use.

The novel features characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Figure 1 is a longitudinal section through a retinoscope made according to this invention.

Figure 2 is a cross-sectional view taken along line 2 2 of Figure 1.

Figure 3 is a view taken on line 3--3 of Figure l and showing an image of the streak.

Figure 4 is a longitdinal sectional view of the base of a retinoscope and a plug therefor.

Generally, the retinoscope comprises a handle portion I containing at its lower end a plug 2. Connected to the handle portion are two tubular portions 3 and 4 which are attached to each other in some way, as shown at 5. Surrounding the lower tubular portion 3 is a sleeve 6 which holds part of the optical system. Affxed to the top of the sleeve 4 by friction or by other means is the reecting cap portion 1.

The optical system of the device (in the order in which the light passes through the instrument) comprises a lamp Il! which is specially constructed with a straight filament 20, a positive lens II, a Dove prism I2, a second lens I3 which -is shown in the drawing as a positive lens but which may be a negative lens, the lens I4 which is another positive lens and the reflecting mirror I5. Lamp bulbs with other types of planar filaments may be employed although a straight line filament is preferred because at present it is the easiest of the planar filaments to' construct. By a "planar filament is meant a filament which lies in a single plane which is perpendicular to the direction the light is passed through the tube. v

In the cap portion 'I there is a series of aligned orifices I6, II and I8. The orifice I6 is in the portion of the cap which is directed toward the patients eye. The orifice I1 is directed toward the observers eye and the orice I8 is in the silver mirror I5. The orifice I8 is shown as a hole in the mirror. However, it is possible to just omit the silveringv from the portion in the mirror.

The Dove prism of the optical system is held in a sleeve 2l. The lens I3 is also held in the sleeve 2I by means of a circular indentation 22. The sleeve 2| is held in position within the tubular portion 3 by a set screw 23 which connects it to the sleeve 6. A portion of the tubular portion 3 is cut away as shown at 24 in Figures 1 and 2 so that the sleeve 22 containing the Dove prism and the lens I3 may be rotated about 180 and moved longitudinally. A Dove prism is a trapezoidal shaped prism and it has the property of rotating abeam of light. For every degree of rotation of the prism a beam of light which enters one end of the Doveprism is rotated two degrees so that by providing for 180c7 of rotation in the sleeve 2| the beam of light which comes from the filament 20 can be rotated 360.

The lens II is a'collimating lens and serves to make parallel the rays which come from the iilament 20 of the lens I0. After passing through ril.

the Dove prism the parallel rays pass through the positive lens I3 and form an image of the filament 2B at some point between the said lens i3 and the lens I4. If a screen were placed at line 3-3 of Figure 1 the image projected thereon would be as indicated at 50 of Figure 3. If this image is formed at a distance from I4 which is equal to the focal length of the lens I4 the rays which emerge from the lens I4 will be parallel. The lens I3 can be moved with the Dove prism and depending on the position of the said lens I3 the image of the filament may fall either at the focal point of lens I4, in front of the focal point of the lens I4, or in back of the focal point of the lens I4. When the sleeve 2| and lens I3 are at their lowest point, that is when they project an image of the filament back of the focal point of lens I4, the effect of the resultant rays is the same as that produced by a concave mirror retinoscope, i. e., the rays leaving the retinoscope are sufciently convergent to be focused or crossed in front of the patients eye.

An example of one type of optical system would be a positive lens having a focal length of 25 mm. at Il, a positive lens having a focal length of 19 mm. at I3; and a positive lens having a focal length of 50 mm. at I4. By employing a lens at I3 which has a shorter focal length than the lens employed at I I, a filament image of reduced size is produced between the lens I3 and the lens I4. Since it is not practical to reduce the size of the lament 20 in the bulbs l0 too much, this is very advantageous.

An inclination responding switch which is particularly adapted for use with this instrument is shown in Figure 1. This comprises two brass plugs 35 and 36 and a brass lamp socket 30 which are all set in a steel or brass tubular container 32. The brass lamp socket is insulated from the tubular container 32 by a suitable insulating material such as a phenol formaldehyde condensation product, shown at 3l. Similar insulating material 33 is also employed to insulate the steel or brass tube 32, and so forth, from the mercury contact elements. The mercury contact elements comprise a cup-like portion 34 made from ystainless steel and a stainless steel pin 38 reaching into the cup portion. Materials inert to arcing and inert to amalgamating with mercury, such as stainless steel, must be used as the con tact elements.

The plug element 35 is connected to the stainless steel contact element 34 by means of a connector 3l. The lower end of the bulb I0 is connected to the pin connector 38 by means of a spring device 33. The second connection from the bulb to the other plug 36 is made by an insulated wire 4I which is shown as passing from the outside of the bulb ID through the insulating material and the stainless steel to the plug 36. A drop of mercury, by which the electrical connection between the pin or connector 38 and the stainless steel cup 34 is made, is shown at 40. When the instrument is held upright as shown at I the drop of mercury falls by gravity so as to connect the pin 38 and the stainless steel cup 34- and lighting the bulb. When the instrument is placed in a horizontal position the mercury drops back along the side wall of the cup thereby breaking the connection. The insulating material extends downward over the pin 38 as shown at 42 to prevent contact of the mercury with the pin 3B when the instrument is in a horizontal posi` tion or when the instrument isturned downward.

To connect theI retinoscope to a source of lelectricity a suitable female-.plug-is attached-to the prongs 35f and"l 36. If desired a mercury switch of the type shownabove the plugs'35 and 36 may be external tothe tubular assembly and located within the femaleI plug whichis to be attached to thefplugs 35 and 36 making this new feature available tothe older type of instrument.

The modification referred to in the. previous paragraph is shown in Figure 4 of the drawing.

In vthis modification thelamp bulb lil is screwed into the brass socket Sil and one side fof the bulb is connected to the plug 6l throughrthegbrass socket E9. The other plug 62 is connected by screw 63 to the centerfconductor Gli-which includes a spring portion-B5, to the center contact 4Il of the lamp bulb. vThe inclinationv'responsive switch is included in the female plug-memberlii. Thejorilice ll. of the .female plug 'lil is-connected by screw l2 to the center conductorf'lS yhaving the pin connector 14 at itslower end.; ,A drop lof mercury 15 is .contained in the .stainlesssteel .cup member 'i6 which is electrically connected to the lead in wire Tl. y The other female plug.y orifice f8@ is connected to the other vlead in wiretl by screw 32 which is insulated Afrom steel cup "i6, The structure is all set in insulating material 83.

It will be seen that there has been; .provideda new and novelstreak retinoscope which .has all the advantages` of the streak retinoscopes now employed and which also has the advantages of not requiring any twisted or longitudinal .movement of the electrical lconnections'.zbetween the lamp bulb and .the connecting plug and any rotation or movement of the lamp bulb itself. It

also has the advantage of providing for the .rotation of the streak the full 360 instead of the usual 18C". The device of the presentinvention also provides for automatically turning off the light bulb when the instrument is placed at rest in a horizont-al position.

Although certain specific embodiments `or .this invention have been shown and described, it will be understood that many modificationsv thereof are'possible. This invention, therefore, is not to be restricted except insofar as isnecessitated by l theprior art and claims.

I claim:

l. In a retinoscope, the combinationcomprislng a tubular housing, a relatively fixed lamp bulb socket adjacent one end ofisaid housing, a lamp bulb in said socket, a first lens means for collimating the light from a bulb held in said socket, a Dove prism with one end thereof located adjacent said lens, a second lens located adjacent the other end of said Dove prism, a slot in said housing, a holder for said Dove prism and said second lens located within said housing, a sleeve mounted for rotation and for longitudinal. movement about the outside of said housing, means passing through the slot in the housing and attached to the sleeve and the holder for the Dove prism whereby the Dove prism and the second lens may be rotated and moved longitudinalh7 with respect to said housing.

2. In a retinoscope, the combination comprising a tubular housing, a relatively xed lamp bulb socket adjacent one end of said housing, a lamp bulb in said socket, a iirst lens means for collimatu ing the light from a bulb held in said socket, a Dove prism located adjacent said lens, a second lens located adjacent said Dove prism, a slot in said housing, a holder for said Dove prism and said second lens located within said housing, a sleeve mounted for rotation and for longitudinal by the Aspirit of the appended movement. about the. outside -of,-sald housing,l

means passing through the slotin the-housing f 3. In a retinoscope, the combination comprisl ing a tubular housing, a relatively fixed lamp bulb socket adjacent one end of said housing, a lamp bulb in said socket having a geometrically shaped planar lilament, a iirst lens means for collimating the light vfrom a bulb held in said socket, a Dove prism located adjacent said lens, a second lens located adjacent said 4Dove prisrmxa slot in said housing, a holderv for said Dove prism and said second lens located within said housing, a sleeve mounted for rotation and fcrglongitudinalzmovement about the outside of said housing, means passing through the slot in the housing. and. attached to the sleeve and the holder for the Dove prism whereby the Dove prism and the second lens .may beirotated ,andv moved longitudinally with respect to said housing, a third lens located adjacent the end of lthe tubular housing opposite to the lamp socket. adapted to projecten image whereby the rays proiected from-said third lens may be made parallel, converent, or divergent depending upon the longitudinalposition of the sleeve and the second lens.

4. In a streak retinoscope, the vcombination comprising a tubular housing, a relatively fixed lamp bulb socket' adjacent one end of said housing. a linear iilament lamp bulb in said socket, a rst lens means for vc'ollimating the light from a bulb held in said socket, a Dovepr'ism located adjacent said lens, a second lens located adjacent said Dove prism, a slot in said housing, a holder for said Dove. prism and said second lens located Within lsaid housing. a sleeve mountedv for rotation and for longitudinal movement about the outside of said housing, means pass ing through theslot in the housing and attached to the sleeve and the holder-"for the Dove prism whereby the Dove prism and the second lens may berotated and moved longitudinally with respect to said housing, a third lens located adjacent the end of the tubular housing opposite to the lamp socket adapted to proiect an image whereby the rays projected from said third lens may be made. parallel, convergent or divergent depending uponv thelongitudinal position of the sleeve and the second lens.

, 5. In a retinoscope, the combination comprising a tubular housing, means for producing a planar figure of light adjacent one end of said housing, a first lens means for collimating the light from the light producing means, a Dove prism with one end thereof located adjacent said lens, a second lens located adjacent the other end of said Dove prism, a slot in Said housing, a holder for said Dove prism and said second lens located within said housing, a sleeve mounted for rotation and for longitudinal movement about the outside of said housing, means passing through vthe slot in the housing and attached to the sleeve and the holder for the Dove prism whereby the Dove prism and the second lens may be rotated and moved longitudinally with respect 'I5 to said housing.

6. In a streak retinoscope, the combination comprising a tubular housing, a relatively fixed lamp bulb socket adjacent one end of said housing, a lamp bulb having a linear filament in said socket, a rst lens means for collimating the light from a bulb held in said socket, a Dove prism located adjacent said lens, a second lens located adjacent said Dove prism, a slot in said housing, a holder for said Dove prism and said second lens located within said housing, a sleeve mounted for rotation and for longitudinal movement about the outside of said housing means passing through the slot in the housing and attached to the sleeve and the holder for the Dove prism whereby the Dove prism and the second lens may be rotated and moved longitudinally with respect to said housing, a third lens located adjacent the end of the tubular housing opposite to the lamp socket adapted to project an image whereby the rays projected from said third lens may be made parallel, convergent, or divergent depending upon the longitudinal position of the sleeve and the second lens, two terminal elements for connectingY said bulb socket with a source of electric current,

one of said terminal elements being connected directly to a contact for one electrode of said bulb, a mercury switch comprising a cup-like element housing, a third lens located adjacent the end of the tubular housing opposite to the means for producing the planar figure of light adapted to project an image whereby the rays projected from said third lens may be made parallel, convergeht or divergent depending upon the longitudinal position of the sleeve and the secondlens in said housing.

8. In a retinoscope, the combination comprising a housing, means for producing a linear line of light substantially perpendicular to the axis of and adjacent one end of said tubular housing, a iirst lens means for collimating the light from said line of light, a Dove prism located adjacent said lens, a second lens located adjacent said Dove prism, a slot in said housing, a holder for said Dove prism and said second lens locatedV within said housing, a sleeve mounted for rotation and for longitudinal movement about the outside of said housing, means passing through the slot in the housing and attached to the sleeve and the oi stainless steel, a prong-like element extending into said cup, and a drop of mercury within the cup-like element adapted to contact the pronglike element when the tubular housing and bulb is held upright to connect the second terminal element to the other electrode of said bulb, the lamp socket and the mercury switch being held in a single sealed unit detachably connected to the end of the tubular housing.

' 7. In a retinoscope, the combination comprising a tubular housing, means for producing a planar iigure` of light substantially perpendicular to the axis ci and adjacent one end of said tubular housing, a first lens means for collimating the light from a said planar figure of light, a Dove prism located adjacent said lens, a second lens located adjacent said Dove prism, a slot in said housing, a holder for said Dove prism and said second lens -located within said housing, a sleeve mounted for rotation and for longitudinal movement about the outside of said housing, means passing through the slot in the housing and attached to the sleeve and the holder for the Dove prism whereby the Dove prism and the second lens may be rotated holder for the Dove prism whereby7 the Dove prism and the second lens may be rotated and moved longitudinally with respect to said housing, a third lens located adjacent the end of the tubular housing opposite to the means for producing the linear line of light adapted to project an image whereby the rays projected from said third lens may be made parallel, convergent or divergent depending upon the longitudinal position of the sleeve and the second lens in said housing.

JACOB C. COPELAND.

REFERENCES CIIEDl The following references are of record in the iile of this patent:

UNITED STATES PATENTS

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