US2201811A - Scanner - Google Patents

Scanner Download PDF

Info

Publication number
US2201811A
US2201811A US211142A US21114238A US2201811A US 2201811 A US2201811 A US 2201811A US 211142 A US211142 A US 211142A US 21114238 A US21114238 A US 21114238A US 2201811 A US2201811 A US 2201811A
Authority
US
United States
Prior art keywords
mirror
coil
motion
electrical impulses
stem
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US211142A
Inventor
Stewart L Clothier
Harold C Hogencamp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KOLORAMA LAB Inc
KOLORAMA LABORATORIES Inc
Original Assignee
KOLORAMA LAB Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by KOLORAMA LAB Inc filed Critical KOLORAMA LAB Inc
Priority to US211142A priority Critical patent/US2201811A/en
Application granted granted Critical
Publication of US2201811A publication Critical patent/US2201811A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/02Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only
    • H04N3/08Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only having a moving reflector

Description

y 1940. s. L. CLOTHIER :1- AL 2,201,811
acumen Filed June'l, 193a 2 Sheets-Sheet 1' INVENTORS ATTORNEY May-21, 1940.
' s. 1.. CLOTHIER El AL 2,201,811
SCANNER Filed June 1, 1938 2 Sheets-Sheet 2 I INVENTORS 5 TzM/A/a 7 z. (jam/2'2 ATTORNEY Patented May 21, 1940 UNITED STATES PATENT OFFICE Hogencamp,
Irvington,
N. J., assignors to Kolorama Laboratories, Inc., Newark, N. J., a corporation of New Jersey Application June 1, 1938, Serial No. 211,142
5 Claims. (01. 178-16) This invention relates to scanning mechanism and more particularly to electromagnetic means for oscillating a pivotally mounted mirror.
In television scanning systems, oscillographs, and the like, it is often necessary to periodically produce an angular deviation of a mirror in response to electrical impulses. The results are often times obtained through the use of a magnetically permeable armature connected to an oscillatable mirror, or through the use of a properly designed rotating cam and follower mechanism suitably connected to the mirror.
Moving armatures oscillated by the intermittent electrical impulses have the disadvantage of having relatively great weight and the attendant disadvantage of being unable to respond to high frequency electrical impulses because of the inertia of the moving parts. Cams have proven satisfactory as a driving medium but they are subject to the disadvantage that they are relatively expensive to fabricate and the motion produced is limited strictly by the design of the cam. Furthermore, such cams are exposed to. wear, they must be rotated at constant speed, and they operate with relatively high inertia.
In the present invention it is proposed to utilizethe flexibility of the electrical wave-form to obtain any desired mechanical wave form.
The objects, therefore, of the present invention are: to provide an improved scanning mechanism operable by electrical impulses; to provide in such a mechanism mirror-oscillating means having a minimum inertia to motion; to provide in such mechanism means comprising a moving coil for reaction with the electrical impulses; to provide improved means for flexibly connecting the moving coil with the mirror; and to provide means for minimizing chattering of the device at operating frequencies. These and'other objects will become more readily apparent from the following description in conjunction with the appended drawings showing one form of scanning mechanism incorporating the present invention.
In the drawings:
Fig. 1 is a vertical sectional view taken through the improved scanning mechanism;
Fig. 2'is a sectional view taken on the line 2-2 of Fig. 1;.
Fig. 3 is a detail sectional view taken on the line 33 of Fig. 2; and
Fig. 4 is a view of a modified form of mirror connecting means.
Briefly, the invention comprises a magnet and coil construction of a typesimilar to that employed with dynamic loudspeakers. .A. magnet M generates magnetic lines of force across an air gap, preferably of annular shape, and a moving coil C assembly corresponding in design with the voice coil of a dynamic loudspeaker is located within the annular gap so as to intercept the magnetic lines of force. A connecting link L extends from the moving coil assembly to a pivotally mounted mirror assembly P in such a way that movement of the coil imparts an angular motion to the mirror about the axis of the pivotal mounting.
Referring now in greater detail to the drawings, the magnet M comprises a permanently magnetized core structure II of steel, nickel-iron alloy or other suitable material having high permeability and rententivity. The core structure I I, as shown in the drawing, comprises an annular shell I2 having a centrally located pole-piece I3 mounted to a bridging top plate I4. An annular base plate I5 is secured to the shell I2 so as to complete the magnetic path with the bottom of the pole-piece I3 through an intermediate air-gap I6 preferably of annular shape. The base plate I5 is relatively thick and its central aperture is dimensionedso as to be but slightly larger than the diameter of the pole-piece I3 so that the annular magnetic path formed comprises a deep space with but a narrow gap between the adjoining parts so as to provide an intense radial magnetic field in the air gap. A tubular dome ll of non-magnetic material such as cardboard, fiber, or the like extends within the airgap closely about the pole-piece I3 and is provided with a winding of small insulated wire about its outer periphery, the terminals I9 of which extend downwardly from the dome I! for connection with a source of electrical impulses. The dome I! is supported by a diaphragm 2| of paper or the like preferably provided with a series of annular corrugations, which diaphragm permits the coil to move in an axial direction but inhibits its motion transversely. The diaphragm 2I is secured directly against the base plate I5 by means of a clamping ring 22. The movable coil C comprising the dome I1 and the winding I8 is joined with the pivotally mounted mirror P by means of the connecting link L comprising a stem 23 secured at the base of the dome I 1 by means of a machine screw 24 and reinforcing Washers 25. The stem is slidably mounted within a bushing 26 disposed axially about the stem in spaced relation to the dome II. The bushing is firmly secured within a support 21 extending from the base plate I5.
The pivotally mounted mirrorP comprises a a sheet of reflecting material such as polished metal, silvered glass, or the like firmly secured to a spindle 30, having axially located sockets 31 at the respective extremities thereof. A pair of pivot mounting blocks 32 are secured to a base member 33 as by screws 34. Pivots 35 preferably comprising threaded rods having hardened conical points 36 extend through the blocks 32 into the respective sockets 3| at each end of the spindle 30. The pivots 35 are adjusted until the spindle pivots freely without lost motion, at which time locknuts 31 are tightened to hold the pivots in the adjusted position. A radius arm or pivoting link 38 is tightly secured to the spindle 30 as by means of a locking screw 33. The radius arm 38 connects with the stem 23 through a resilient link 4| preferably comprising a thin strip of tempered spring steel secured in any convenient manner at its opposite ends to the stem 23 and the arm 38. The magnet M is supported in fixed relation to the base member 33 by a plurality of legs 42.
The device operates as a scanning mechanism by projecting a beam of light upon the pivotally mounted mirror P and attaching the terminals l9 to the source of electrical impulses. Presuming for example that the electrical impulses comprise intermittent surges of electric current as an alternating current sine-wave, the current passing through the winding l8 exerts alternating impulses in the highly concentrated magnetic field in the air-gap l6 with the effect that the movable coil C is subjected to an oscillating motion along the axis of the stem 23. This motion is imparted through a resilient link 6| to the radius arm 38 causing the pivotally mounted mirror P to oscillate angular-1y, thus imparting the desired scanning motion to the reflected light beam. With an exciting impulse of sine-wave shape, the miror is oscillated substantially according to simple harmonic motion. As the arm 38 pivots from the horizontal position shown in Fig. 1 its lateral distance from the stem 23 decreases. This motion is of such small magnitude, however, that it is compensated for by fiexing of the link 4|. At the same time the tendency for the flexible link to return to a straight position maintains the parts under a slight tension and operates to minimize chattering when the device is in operation.
In Fig. 4 a slight modification of the connecting link L is shown. Instead of the resilient link 4| use is made of a flexible cable, cord, or chain 43 which is operative to lift the radius arm 38 whenever the stem 23 is raised, and a helical tension spring 44 is secured to the arm 38 so as to return the arm to the lower position whenever such motion is permitted by a corresponding lowering of the stem 23. With the modified arrangement there is less tendency for a sideways force to be exerted against the stem 23 as might be exercised by a resilient link 4|, which pressure may increase the friction between the stem 23 and the bushing 26 if the angular motion is excessive.
It will be noted that the, magnetic forces of the moving parts are obtained without the use of an iron armature or its equivalent, and the weight of the moving parts has been maintained at a minimum. The repulsion and attraction is obtained through the use of a light-weight moving coil which provides for accurate response even at comparatively high frequencies of the electrical impulses, as the moving parts do not possess the high inertia of an iron armature. Furthermore, the elimination of iron from the moving parts eliminates hysteresis as a factor limiting the frequency of operation. Since the design incorporates features of the dynamic loudspeaker the limiting operating frequency may be estimated roughly as the highest pitch note to which such type of speaker responds, as the inertia of the oscillating mirror and the connecting link does not differ materially from the mechanical inertia of the usual paper cone. A dynamic speaker may be converted to use in the improved scanner by removing the cone from the unit, and by suitably connecting the mirror to the moving coil assembly,
In practice we have found that at all ordinary television frame-scanning frequencies, this device readily reproduces mechanically the wave-form of the exciting current, irrespective of its shape. For example double, and even single sawtooth wave-forms are faithfully reproduced.
It will be appreciated, of course, that while a T magnet of the permanently magnetized type has been shown, electromagnetic units for generating the annular fiux field may be employed equally well.
The corrugated diaphragm 2| herein described exerts a steadying influence on the motion of the coil assembly. The inertia of this diaphragm may be lessened by forming lightening holes therein, or the diaphragm may be formed as a spider having radial supporting arms similar to the support 21. In some cases the diaphragm may be eliminated entirely, rendering the device more sensitive at high frequencies.
Obviously, the connection between the mirror and the moving coil may be of any suitable de sign. The dome disclosed is desirable in that it provides a rigid connection having light weight.
Various other changes will suggest themselves to one skilled in the art without departing from the scope of the invention or sacrificing any of its advantages.
We claim:
1. In combination a dynamic unit having a coil movable in an annular magnetic field and responsive to electrical impulses, a member connected for movement axially with said coil, a pivotally movable scanning mirror, and means connecting the said member and mirror to oscillate the latter and compensating for the arcuate movement of the mirror in translating the linear movement to oscillating motion.
2. In combination a dynamic unit having a coil movable in an annular magnetic field and responsive to electrical impulses, a member connected for movement axially with said coil, a
pivotally movable scanning mirror, and flexible means connecting the said member and mirror to oscillate the latter and compensating for the arcuate movement of the mirror in translating the linear movement to oscillating motion.
3. In combination a dynamic unit having a coil movable in an annular magnetic field and responsive to electrical impulses, a member connected for movement axially with said coil, a
pivotally movable scanning mirror, and resilient .1.
means connecting the said member and mirror to oscillate the latter and compensating for the arcuate movement of the mirror in translating the linear movement to oscillating motion.
4. In combination a dynamic unit having a coil movable in an annular magnetic field and responsive to electrical impulses, a member connected for movement axially with said coil, a pivotally movable scanning mirror, and leaf spring means connecting the said member and pivotally movable scanning mirror, and means connecting the said member and mirror to oscillate the latter and compensating for the armate movement of the mirror in translating the linear movement to oscillating motion and tension means assisting the oscillatory movement.
STEWART L. CLOTHIER. HAROLD C. HOGENCAMP.
US211142A 1938-06-01 1938-06-01 Scanner Expired - Lifetime US2201811A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US211142A US2201811A (en) 1938-06-01 1938-06-01 Scanner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US211142A US2201811A (en) 1938-06-01 1938-06-01 Scanner

Publications (1)

Publication Number Publication Date
US2201811A true US2201811A (en) 1940-05-21

Family

ID=22785732

Family Applications (1)

Application Number Title Priority Date Filing Date
US211142A Expired - Lifetime US2201811A (en) 1938-06-01 1938-06-01 Scanner

Country Status (1)

Country Link
US (1) US2201811A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2573998A (en) * 1945-11-23 1951-11-06 Nea Service Inc Oscillograph-galvanometer
US2768350A (en) * 1952-01-15 1956-10-23 Cons Electrodynamics Corp Galvanometers

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2573998A (en) * 1945-11-23 1951-11-06 Nea Service Inc Oscillograph-galvanometer
US2768350A (en) * 1952-01-15 1956-10-23 Cons Electrodynamics Corp Galvanometers

Similar Documents

Publication Publication Date Title
US1808149A (en) Electrodynamic speaker
US2164374A (en) Sound reproducing device
US2201811A (en) Scanner
US1573739A (en) Telephonic device
US1674895A (en) Method of and apparatus for radiating sound waves
US2059159A (en) Vibratory mirror system
US2133815A (en) Phonograph reproducer
US1897294A (en) Loud speaker and like apparatus
US1844605A (en) Acoustic device
US1711514A (en) Electromagnetic driving unit
US3828144A (en) Vibration absorbing support for loudspeaker voice coil bobbin
US2240918A (en) Device to convert mechanical vibrations into electrical oscillations
US1866361A (en) Driving unit for loud-speakers
US1915804A (en) Electrodynamic pickup
US1645139A (en) Mechanical vibratory system
US2835832A (en) Vibration generating apparatus
US1667021A (en) Translator of electrical energy
US1577254A (en) Sound reproducer
US2471365A (en) Armature structure for electromagnetic apparatus
US1643169A (en) Telephone receiver
US1525182A (en) Sound transmitter and receiver
US1783569A (en) Electrodynamic signal device
US2065907A (en) Translating device
US1632134A (en) Electromagnetic device
US1682866A (en) Electrical instrument of the telephone type