US2475444A - Optophone - Google Patents

Description

July 5, 1949 J. A. cAsl-uu. 2,475,444

' OPTOPHONE I Filed Sept. 18, 1946 mm ran UM QM Patented July 5, 1949 OP'IOPHONE James Andrew Cashin, Liverpool, England Application September 18, 1946, Serial No. 697,821 In Great Britain September 27, 1945 6 Claims.

This invention relates to so-called optophones or apparatus for representing printed characters as combinations of sounds. Such apparatus enables a blind person to read ordinary printing by ear.

As previously proposed a plurality of light beams each modulated at a different frequency has been used to eifect scanning of parts of successive let? ters in a word or line, the resultant reflected light being detected by photoelectric means connected to electric wave responsive sound generating means. A disadvantage which has presumably rendered this prior contruction impracticable or unsuccessful is to be found in the minuteness and extreme precision required in the projection of the various beams of modulated light in correct mutual relationship. This invention seeks to avoid these disadvantages.

According to this invention, a magnified image of part or all of the type is projected on to a perforate screen, mask or other image dividing and selecting means, before modulation and detection, a single photoelectric means being used to detect all the modulated light components.

The image is magnified and cast relatively sharply upon a perforate screen through dilferent perforations through which pass selected light components. The selected increments are then each modulated characteristically, conveniently by a rotary plate having a plurality of coaxially disposed groups of slo The apparatus may be rendered black-sounding by simultaneously projecting an image from a white or neutral blank object, simultaneously dividing said image and difierentially modulating each increment of the blank image with respect to a corresponding increment of the printed character image.

This may be effected by spacing the corre+ sponding selection holes at any interval on the mask, said interval corresponding exactly to the length of the corresponding modulator slit and land between successive corresponding modulator slits.

The invention will be described further by way of example with reference to the accompanying drawings in which:

Figure 1 is a fragmentary side elevation of a modulator disc or sector.

Figure 2 is a fragmentary side elevation of a perforate screen or mask;

Figure 3 is a diagrammatic apparatus.

Referring to the drawings, the paper to be plan of one form of read is placed upon a plane or curved surface a capable of movement in two directions; one direction being in line with the lines of print, the other being across them. Light from lamps b and bl is directed partly onto the paper and partly onto a tongue t made of white material so as to give a similar reflection to paper. The characters are moved across this light in turn. Light reflected from the paper andtongue is collected by lens c and a moving image of each character is thrown onto the screen d, which carriesa number of holes I and g. A disc e parallel to the screen has a number of coaxially disposed groups of, i. e., rings of circumferential slots (with radial edges'll and is rotated by an electric motor at a speed which may be varied at will.

Holes 1 and g in the screen 01 are located at radial distances such as to coincide with rings of slots in disc e the pair of holes at each radius in the screen d being set at centres equal to the length of the corresponding slots in the disc 6. In each ring, in disc e, the space between a pair of slots is equal to the length of a slot. The ratios of the number of slots in each ring are re lated in a manner similar to the relationship be tween the frequencies of a series of notes in a musical scale. A photo-electric cell h is placed in line with the screen and disc, so that light projected through the holes in the screen, and through the slots in the rotating disc, falls on its cathode. The photo-cell is connected through an amplifier k to a loudspeaker l or headphones.

Light from the printed sheet is projected onto and through holes and is varied by the image of the printed character as it moves over them, whilst, at the same time an unvarying light reflected from the tongue it passes through holes When there is no printed character under the light on the page, an equal amount of light is projected through holes and g. This light is interrupted by the slots in the disc e in such a way as to allow light to pass through holes ,1 and g alter nately, decreasing in one at the same rate at which it increases in the other, thus a steady unvarying light falls on the photo-cell and no sound is heard.

When a printed character causes variation in the light passing through holes I, the light reaching the proto-cell becomes modulated in such a way as to give rise to a series of musical notes, each printed character having a characteristic tune which is learned by the operator.

This is effected as follows: Reflected beams of light are projected on to the holes j and g respectively. That beam coming from the tongue a is projected on to the holes 9 while the other beam coming from the letter to'be"rea'd is projected on to the holes f. The relative positions of the holes ,1 and g are so chosen with respect to the width of the apertures of the holes that the i1} lurninat ion of the photo-electric cell 71 is constant when both beams are of equal strength, but when the beam reflected by the letter is weaker, owing to absorption by the black ink, this beam is interrupted so many times per second, that a current corresponding to a musical note is produced in the 3 photo-electric cell. Different portions of the beam cor-responding to different parts of the letter, each produce its characteristic note, so that the letter as a whole can be recognized.

To allow for different reflecting indices of different papers, the intensit or direction of the light reaching holes 1 and 9 ma be varied by adjusting the light from lamps b and bl. In an alternative form of construction, one lamp only, possibly with two filaments, may be used.

Print of different sizes may be read by adjusting the optical distance between the page and the screen d, the lenses being automatically kept at the correct focus. A reflecting prism or prisms may be interposed between lens 0 and screen d, to change the direction of the beam, and/or to shorten the actual distance between these points whilst maintaining the greater optical distance. By rotating one of the prisms through a small angle, the beam may be rotated to enable sloping characters such as italics or handwriting to be read. Varying the optical distance may be effected by moving one of the prisms towards or away from thescreen d.

The slots in disc e are made wider in a radial direction than the holes in the screen cl, and the screen may be rotated to present different sets of holes for reading different type, such as italics, or characters with thicker or thinner lines.

Holes 1 in screen 11 may be radial to sound a musical chord or staggered to sound the notes of the musical scale in succession.

In order to reduce the size of the light and/or to spread it more evenly over the cathode of the photo-cell a lens 7' may be interposed between the rotating disc e and the photo-cell.

Whilst the invention is especially applicable for representation of printed characters produced by inked type it is obvious that such printed characters need not necessaril have been produced by inked type. The word printed in the description and claims is intended to include characters produced photographically, lithographically, by the use of hand writing instruments and otherwise.

I declare that what I claim is:

1. An apparatus for representing printed characters as combinations of sound, comprising image dividing and selecting means for producing a plurality of image components, means to project an enlarged moving image of at least part of a character onto said dividing and selecting means, means for distinctively modulating each component, and a single photo-electric means for detecting the modulated components.

2. An apparatus, for representing printed characters as combinations of sound, comprising image dividing and selecting means for producing a plurality of image components, means to project a moving image of at least part of a character onto said dividing and selecting means, means for intermittently masking each component at distinctive frequency a single photoelectrio means responsive to light from the various intermittently masked components, electroacoustic means for producing sound in accordance with audio frequency electric currents, and electric circuit means connected to said photoelectric means and to said electro-acoustic means whereby audio frequency electric currents are caused to energize said electro-acoustic means responsive to amplitude and frequency of light 4 received from said intermittently masked components by said photoelectric means.

3. An apparatus, for representing printed characters as combinations of sound, comprising a screen having a plurality of perforations therein, means to project an enlarged image of at least part of a character onto said mask plate so that components of light from the enlarged image can pass through the perforations, means for distinctively modulating each component with a distinctive frequency, and means for producing sounds responsive to the frequencies and amplitudes of the respective modulated components.

4. An apparatus, for representing printed characters as combinations of sounds, comprising a.

screen having two sets of perforations therein,, means to project an enlarged moving image of.

at least part of a character onto said screen so that selected light components thereof pass through one set of perforations, means to project light of background intensity onto said screen so that selected components thereof pass through the other set of perforations; means for simultaneously differentially modulating each component from the first set of perforations with respect to a component from the second set of perforations with a distinctive frequency, and means for detecting the differentially modulated pairs of components.

5. An apparatus, for representing printed characters as combinations of sounds, comprising means for projecting a moving image of a character, means for projecting an image from a neutral blank object of background intensity, a screen having two sets of perforations therein for receiving said images each in the region of one set of perforations, a rotary sector modulator plate having groups of arcuately extending slits and lands of equal interval each group being substantially aligned to modulate by intermittent masking light from pairs of perforations in the screen, whereby the said images are divided by the screen and selected light components from the character image are modulated differentially with respect to the blank image components, and means to detect all the modulated light components and to product sounds corresponding in frequency to the modulation frequency of each modulated component and of intensity corresponding to the amplitude of each modulated component.

6. In apparatus for producing sounds responsive to distinctive modulation frequencies of light components from selected parts of a character, the improvement comprising means to produce an enlarged image of the character, means to divide said enlarged image into components, and means tomodulate each component distinctively.

JAMES ANDREW CASHIN.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,628,077 Tarbox May 10, 1927 1,986,977 Wainright Aug. 7, 1934 2,035,773 Thomas Mar. 31, 1936 2,137,888 Fuller Nov. 22, 1938 2,332,469 Reisz Oct. 19, 1943 2,403,997 Potter July 16, 1946

Images