CA1184286A - Electronically tuneable light source - Google Patents
Electronically tuneable light sourceInfo
- Publication number
- CA1184286A CA1184286A CA000394080A CA394080A CA1184286A CA 1184286 A CA1184286 A CA 1184286A CA 000394080 A CA000394080 A CA 000394080A CA 394080 A CA394080 A CA 394080A CA 1184286 A CA1184286 A CA 1184286A
- Authority
- CA
- Canada
- Prior art keywords
- light
- light source
- band
- medium
- source
- 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
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/11—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An electronically tuneable light source which includes a source of white light, an acousto-optic modulator which includes a transparent medium and a device for generating an acoustical wave in the medium and a focusing and collimating assembly for directing the collimated beam of the white light onto the medium at a preselected angle ?/2, to a line which is perpendicular to the direction of travel of the acoustical wave. Interaction of the light beam with the acoustical wave causes diffraction of the light beam. An aperture in a plate is provided for selecting a visible band of the diffracted beam at an angle to the incident collimated beam of light equal to approximately ?.
An electronically tuneable light source which includes a source of white light, an acousto-optic modulator which includes a transparent medium and a device for generating an acoustical wave in the medium and a focusing and collimating assembly for directing the collimated beam of the white light onto the medium at a preselected angle ?/2, to a line which is perpendicular to the direction of travel of the acoustical wave. Interaction of the light beam with the acoustical wave causes diffraction of the light beam. An aperture in a plate is provided for selecting a visible band of the diffracted beam at an angle to the incident collimated beam of light equal to approximately ?.
Description
~84Z~
ELECTRONICA~LY TUNEABLE LIGHT SOURCE--ACKGROUND OF THE INVENTION
The present invention relates to a light source in which both the colour and intensitv of the light can be changed rapidly be electronic means utilizing an acousto-optic effect.
One method of generating coloured light involves the use of phosphors in combination with impinging elec-tronic beams as is utilized in ~he colour television industry.
However, this method does not produce sufficient light to make it useful for purposes such as high speed image re-cording.
It is well known that colour separation of white light into its individual colour components can be effected by the use of a prism. Unfortunately such a method is not amenable to high frequency control of either the colour and/or the intensity of the selected beam.
SUMMARY OF ~HE INVENrrION
According to the invention there is provided an electronically tuneable light source which includes a source of white light, an acousto-optic modulator having a ~rans-parent medium and means for generating an acoustical wave in the medium. Means are provided for collimating light from the white light source and directing the collimated beam onto the transparent medium at a preselected angle ~/2 to a line which is perpendicular to the direction of travel of the acoustical wave so that the beam is diffracted by the acoustical wave. Means are also provided for selecting a band of the diffracted beam the midpoint of which is at an angle of approximately ~to the direction of incidence of the collimated beam. .
A suitable means of yenerating the wave is by the use of a transducer coupled to the transparent medium together with the application of a periodic electrical signal applied to the transducer of a selectable frequency and amplitude.
Preferably, the electrical signal applied to the transducer is sinusoidal. As a result, the light which emerges from the selecting means has a wave length and '10 intensity which is related to the frequency and amplitude of the applied sinusoidal electrical signal.
Ordinarily any source of white light may be used such as an incandescent`bulb. However, in the event that a high intensity light is required one may employ as the light lS source a Xenon arc. The light source aforesaid ~enerates coloured light in which both the optical wave length and the intensity can be c'hanged at a high rate by electronic means.
The light source is useful, but not limited to, exposing colour film in the process of generating colour images by electronic means. The device may also be used as a source for coloured displays where rapid changes in both colour and intensity are required.
~ he assembly may include three primary light filters for'filtering 'light from the light source into three respective spectral bands of wavelength~ ~2~ and?~3, respectively, befcre entering ~he modulator. Each filt~r is removably insertable between the modulator and the light source in response to an external control signal. The frequency of the acoustical wave generated in the modulator i.s selected in accordance with the wavelength of the spec-tral band of light to be transmitted so as to deflect light of the spectral band through an angle ~
BRIEF DESCRIPTION OF THE DRAWING_ In drawinqs which represent a preferred embodiment of the invention, Figure 1 is a schemati.c view of the device showing the relative orientation of the various components thereof, Figure 2 is a perspective view of the assembled device, Figure 3 is a schematic view of an alternate embodiment of the device employing light filters, and Figure 4 is a perspective view of the device shown in Figure 3r DESCRIPTION OF THE. PREFERRED EMBODIMENTS
-Shown in Figure 1 is a light source consisting of an incandescent bulb 10 light from which is focused by a lens 12 through a small aperture 13 and a second lens 14 into a narrow collimated beam 15. The beam 15 is passed through an Acousto-Optic modulator 16 which is commercially available from Isomet, Coherent Radiation as well as many other suppliers. The operation of the Acousto~Optic modu-lator is well known in the art as a device for deflecting and modulating laser light. In the present application, ho~ever, the modulator 16 acts as an electronically control-led diffraction grating to produce coloured light by reason of the interaction of a transverse acoustic wave set up in the transparent medium with the beam 15~ The acoustic wave is set up in;the modulator 16 by means of applying a sinu-soidal electrical signal of. frequency f and amplitude A at terminal 18 to a transducer 17 coupled to the transparent medium. The acoustic wave set up in the transparent medium of the modulator 16 will be of a frequency and amplitude dependent on the frequency and amplitude of the signal applied to the transducer 17.. The density variations associated with the acoustic wave diffract the collimated beam 15 into its spectral components 19 in a manner similar to a diffraction grating. A fraction of the incident collimated beam 15 passes undiffracted through the modulator 16 and falls onto a plate 20. The plate 20 has an aperture 22 located at an angle ~ with respect to the direction of the undiffracted portion of the incident beam 15 and has a width equal to approximately 1/4.of the total width on the plate 20 of the diffracted visible spectrum. In order to achieve the latter diffraction the angle of incidence onto the transparent medium 16, that is the angle that the incident beam 15 makes with a perpendicular to the direction of travel of the acoustical wave in the transparent medium 16, is equal to ~/2. Ordinarily the size of the aperture 22 will be about 1/4 of the total size of the visible spectrum on the plate 20 so that it provides a broad band of a par ticular colour component.
. Illustrated in Figure 2 is an assembly drawing of the device with a portion ~f-the casing_r.emoved in order to view the internal parts. On one end of a base plate 25 is mounted an incandescent bulb 10. Adjacent to the bulb 10 is a plate 24 disposed perpendicular to ~he base 25 and having
ELECTRONICA~LY TUNEABLE LIGHT SOURCE--ACKGROUND OF THE INVENTION
The present invention relates to a light source in which both the colour and intensitv of the light can be changed rapidly be electronic means utilizing an acousto-optic effect.
One method of generating coloured light involves the use of phosphors in combination with impinging elec-tronic beams as is utilized in ~he colour television industry.
However, this method does not produce sufficient light to make it useful for purposes such as high speed image re-cording.
It is well known that colour separation of white light into its individual colour components can be effected by the use of a prism. Unfortunately such a method is not amenable to high frequency control of either the colour and/or the intensity of the selected beam.
SUMMARY OF ~HE INVENrrION
According to the invention there is provided an electronically tuneable light source which includes a source of white light, an acousto-optic modulator having a ~rans-parent medium and means for generating an acoustical wave in the medium. Means are provided for collimating light from the white light source and directing the collimated beam onto the transparent medium at a preselected angle ~/2 to a line which is perpendicular to the direction of travel of the acoustical wave so that the beam is diffracted by the acoustical wave. Means are also provided for selecting a band of the diffracted beam the midpoint of which is at an angle of approximately ~to the direction of incidence of the collimated beam. .
A suitable means of yenerating the wave is by the use of a transducer coupled to the transparent medium together with the application of a periodic electrical signal applied to the transducer of a selectable frequency and amplitude.
Preferably, the electrical signal applied to the transducer is sinusoidal. As a result, the light which emerges from the selecting means has a wave length and '10 intensity which is related to the frequency and amplitude of the applied sinusoidal electrical signal.
Ordinarily any source of white light may be used such as an incandescent`bulb. However, in the event that a high intensity light is required one may employ as the light lS source a Xenon arc. The light source aforesaid ~enerates coloured light in which both the optical wave length and the intensity can be c'hanged at a high rate by electronic means.
The light source is useful, but not limited to, exposing colour film in the process of generating colour images by electronic means. The device may also be used as a source for coloured displays where rapid changes in both colour and intensity are required.
~ he assembly may include three primary light filters for'filtering 'light from the light source into three respective spectral bands of wavelength~ ~2~ and?~3, respectively, befcre entering ~he modulator. Each filt~r is removably insertable between the modulator and the light source in response to an external control signal. The frequency of the acoustical wave generated in the modulator i.s selected in accordance with the wavelength of the spec-tral band of light to be transmitted so as to deflect light of the spectral band through an angle ~
BRIEF DESCRIPTION OF THE DRAWING_ In drawinqs which represent a preferred embodiment of the invention, Figure 1 is a schemati.c view of the device showing the relative orientation of the various components thereof, Figure 2 is a perspective view of the assembled device, Figure 3 is a schematic view of an alternate embodiment of the device employing light filters, and Figure 4 is a perspective view of the device shown in Figure 3r DESCRIPTION OF THE. PREFERRED EMBODIMENTS
-Shown in Figure 1 is a light source consisting of an incandescent bulb 10 light from which is focused by a lens 12 through a small aperture 13 and a second lens 14 into a narrow collimated beam 15. The beam 15 is passed through an Acousto-Optic modulator 16 which is commercially available from Isomet, Coherent Radiation as well as many other suppliers. The operation of the Acousto~Optic modu-lator is well known in the art as a device for deflecting and modulating laser light. In the present application, ho~ever, the modulator 16 acts as an electronically control-led diffraction grating to produce coloured light by reason of the interaction of a transverse acoustic wave set up in the transparent medium with the beam 15~ The acoustic wave is set up in;the modulator 16 by means of applying a sinu-soidal electrical signal of. frequency f and amplitude A at terminal 18 to a transducer 17 coupled to the transparent medium. The acoustic wave set up in the transparent medium of the modulator 16 will be of a frequency and amplitude dependent on the frequency and amplitude of the signal applied to the transducer 17.. The density variations associated with the acoustic wave diffract the collimated beam 15 into its spectral components 19 in a manner similar to a diffraction grating. A fraction of the incident collimated beam 15 passes undiffracted through the modulator 16 and falls onto a plate 20. The plate 20 has an aperture 22 located at an angle ~ with respect to the direction of the undiffracted portion of the incident beam 15 and has a width equal to approximately 1/4.of the total width on the plate 20 of the diffracted visible spectrum. In order to achieve the latter diffraction the angle of incidence onto the transparent medium 16, that is the angle that the incident beam 15 makes with a perpendicular to the direction of travel of the acoustical wave in the transparent medium 16, is equal to ~/2. Ordinarily the size of the aperture 22 will be about 1/4 of the total size of the visible spectrum on the plate 20 so that it provides a broad band of a par ticular colour component.
. Illustrated in Figure 2 is an assembly drawing of the device with a portion ~f-the casing_r.emoved in order to view the internal parts. On one end of a base plate 25 is mounted an incandescent bulb 10. Adjacent to the bulb 10 is a plate 24 disposed perpendicular to ~he base 25 and having
2~
a cen~ral--aperture which aets a-s-a mount for the lens 12.
Adjacent the plate 24 is a plate 26 ha~ing a small aperture 13. Located adjacent the plate 26 is a second lens holder 28 having an aperture for mounting the second lens 14.
Lenses 12 and 14 in conjunction with aperture 13 form a collimator. The Acousto-Optic modulator 16 is mounted at a small angle ~/2 to a plane which is perpendicular to the direction of the collimated beam 15 emerging from the second lens 14. At one end of the modulator 16 there is mounted a transducer 17 acoustically coupled to the transparent medium of the modulator 16. A terminal 18 is provided for coupling to an external electrical signal source (not shown~. At the end of the base plate 25 opposite the çnd where the in-candescent ~ulb 10 is mounted is an image plate 20 which eontains an aperture 22 sueh that the angle between the direction of the incident beam 15 and the center of theaperture is equal to ~.
In operation the desired colour of the output ~eam 21 from the aperture 22 can be selected by changing the frequency f of the sinusoidal signal applied to terminal 18 of the transducer. A given colour will emerge through aperture 22 at an angle accoxding to ~he following for-mula:
v (I) where:
= wavelength of desired colour (in air~
f = frequency of the acoustic wa~e or the applied sinusoidal signal and z~
v ~ the velocity of the acoustic wave~inside the transparent medium of the modulator 16.
The size of the aperture 22 determines the spectral purity of the colour beam 21.
The intensity of the colour beam 21 can be chanyed by changing the amplitude A of the applied sinusoidal signal. The relationship between the light intensity I of beam 21 and the amplitude A of the applied sinusoidal signal is given by the following: -I = Kl sin K2A (2) 7' where:
~ = wavelength of the desired colour, and Xl K2 ~ constants.
As the modulation band width of the Acousto-Optic modulator 16 is inversely proportional to the diameter of the collimated beam 15, the latter beam is made as narrow as required to achieve the desired band width. Since the ~0 Acousto-Optic modulator 16 is a linear device more than one frequency may be applied at the same time to the transducer 17. By way of example, if signals with frequencies fl~ f2 and f3 with corresponding amplitudes Al , A2 and A3 are applied to transducer 17 at the same time, the output beam 21 will contain wavelengths ~~ 2'7~3' intensities, Il, I2, and I3 with I related to A and f by equations ~1) and (2~.
A variant of the assembly of Figure 1 i5 shown in Figu~es 3 and 9.in which a set of three primary light filters lla, llb and llc are adapted to be selectably alternately removably inserted between bulb 10 and lens 12 in response to an external control signal (not shown).
The filters are mounted on a wheel 30 at equal spaced apart angular intervals 120 and the wheel 30 rotated through successive 120 increments in response to the external control signal so that a~ each stop a filter is between the bulb 10 and lens 12. The wheel 30 has a pulley groove 32 for receiving a driven pulley belt (not shown) and îs mounted to base plate 25 by a bracket 33. Other systems whereby desired filters are removably insertable will be obvious to those skilled in the art.
Each filter lla, llb and llc passes a primary spectral band of light characterized by a wavelength 2 and ~3 each different so that the combination of the three bands can produce any colour in the visible spectrum. Thus upon receipt of a given control signal j, a corresponding filter is inserted resulting in light of a spectral band having a wavelength~j passing through the filter and into the modulator 16. A sinusoidal signal of amplitude Aj and frequency fj is applied to the transducer 17 resulting in deflection of light of wavelength~j through an angle e so that the latter passes through aperture 22 with an intensity Ij related to the amplitude Aj. ThP
foregoing-step--is repeated ~or each of--the-three filters so that the combined light signals when recorded on a oolour sensitive film produces an image of a colour and in~ensity related to the wavelengths and intensities of the corres-ponding three component light signals. Thus by the appli-%8~
cation of amplitude valu~s for each of the three frequencies fl/ f2 and f3 an associated colour and intensity of image can be produced on an suitable image recorder such as colour sensitive film.
Other variations, modifications and departures lying within the spirit of the invention and scope as defined by the appended claims will be obvious to those skilled in the a~tO
a cen~ral--aperture which aets a-s-a mount for the lens 12.
Adjacent the plate 24 is a plate 26 ha~ing a small aperture 13. Located adjacent the plate 26 is a second lens holder 28 having an aperture for mounting the second lens 14.
Lenses 12 and 14 in conjunction with aperture 13 form a collimator. The Acousto-Optic modulator 16 is mounted at a small angle ~/2 to a plane which is perpendicular to the direction of the collimated beam 15 emerging from the second lens 14. At one end of the modulator 16 there is mounted a transducer 17 acoustically coupled to the transparent medium of the modulator 16. A terminal 18 is provided for coupling to an external electrical signal source (not shown~. At the end of the base plate 25 opposite the çnd where the in-candescent ~ulb 10 is mounted is an image plate 20 which eontains an aperture 22 sueh that the angle between the direction of the incident beam 15 and the center of theaperture is equal to ~.
In operation the desired colour of the output ~eam 21 from the aperture 22 can be selected by changing the frequency f of the sinusoidal signal applied to terminal 18 of the transducer. A given colour will emerge through aperture 22 at an angle accoxding to ~he following for-mula:
v (I) where:
= wavelength of desired colour (in air~
f = frequency of the acoustic wa~e or the applied sinusoidal signal and z~
v ~ the velocity of the acoustic wave~inside the transparent medium of the modulator 16.
The size of the aperture 22 determines the spectral purity of the colour beam 21.
The intensity of the colour beam 21 can be chanyed by changing the amplitude A of the applied sinusoidal signal. The relationship between the light intensity I of beam 21 and the amplitude A of the applied sinusoidal signal is given by the following: -I = Kl sin K2A (2) 7' where:
~ = wavelength of the desired colour, and Xl K2 ~ constants.
As the modulation band width of the Acousto-Optic modulator 16 is inversely proportional to the diameter of the collimated beam 15, the latter beam is made as narrow as required to achieve the desired band width. Since the ~0 Acousto-Optic modulator 16 is a linear device more than one frequency may be applied at the same time to the transducer 17. By way of example, if signals with frequencies fl~ f2 and f3 with corresponding amplitudes Al , A2 and A3 are applied to transducer 17 at the same time, the output beam 21 will contain wavelengths ~~ 2'7~3' intensities, Il, I2, and I3 with I related to A and f by equations ~1) and (2~.
A variant of the assembly of Figure 1 i5 shown in Figu~es 3 and 9.in which a set of three primary light filters lla, llb and llc are adapted to be selectably alternately removably inserted between bulb 10 and lens 12 in response to an external control signal (not shown).
The filters are mounted on a wheel 30 at equal spaced apart angular intervals 120 and the wheel 30 rotated through successive 120 increments in response to the external control signal so that a~ each stop a filter is between the bulb 10 and lens 12. The wheel 30 has a pulley groove 32 for receiving a driven pulley belt (not shown) and îs mounted to base plate 25 by a bracket 33. Other systems whereby desired filters are removably insertable will be obvious to those skilled in the art.
Each filter lla, llb and llc passes a primary spectral band of light characterized by a wavelength 2 and ~3 each different so that the combination of the three bands can produce any colour in the visible spectrum. Thus upon receipt of a given control signal j, a corresponding filter is inserted resulting in light of a spectral band having a wavelength~j passing through the filter and into the modulator 16. A sinusoidal signal of amplitude Aj and frequency fj is applied to the transducer 17 resulting in deflection of light of wavelength~j through an angle e so that the latter passes through aperture 22 with an intensity Ij related to the amplitude Aj. ThP
foregoing-step--is repeated ~or each of--the-three filters so that the combined light signals when recorded on a oolour sensitive film produces an image of a colour and in~ensity related to the wavelengths and intensities of the corres-ponding three component light signals. Thus by the appli-%8~
cation of amplitude valu~s for each of the three frequencies fl/ f2 and f3 an associated colour and intensity of image can be produced on an suitable image recorder such as colour sensitive film.
Other variations, modifications and departures lying within the spirit of the invention and scope as defined by the appended claims will be obvious to those skilled in the a~tO
Claims (9)
1. An electronically tuneable light source comprising:
(a) a source of white light;
(b) an acousto-optic modulator having a trans-parent medium and means for generating an acoustical travel-ling wave in said medium;
(c) means for collimating light from said source and directing the collimated beam of said white light onto said medium at a preselected angle .THETA./2 to the perpendicular to the direction of travel of the travelling acoustic wave whereby said beam is diffracted by the acoustic wave;
(d) means for selecting a band of the diffracted beam the midpoint of which band is at an angle of approxi-mately .THETA. to the direction of incidence of the collimated beam.
(a) a source of white light;
(b) an acousto-optic modulator having a trans-parent medium and means for generating an acoustical travel-ling wave in said medium;
(c) means for collimating light from said source and directing the collimated beam of said white light onto said medium at a preselected angle .THETA./2 to the perpendicular to the direction of travel of the travelling acoustic wave whereby said beam is diffracted by the acoustic wave;
(d) means for selecting a band of the diffracted beam the midpoint of which band is at an angle of approxi-mately .THETA. to the direction of incidence of the collimated beam.
2. An electronically tuneable light source comprising:
(a) a source of white light;
(b) an acousto-optic modulator including a transparent medium and a transducer coupled to said medium for generating an acoustical wave in said medium by means of a periodic electrical signal applied to the transducer of a selectable frequency and amplitude;
(c) means for collimating light from said source and directing the collimated beam of said white light onto said medium at a preselected angle .THETA./2 to the perpendicular to the direction of travel of the acoustical wave whereby said light is diffracted by the acoustical wave;
(d) means for selecting a band of the diffracted beam, the midpoint of which band is at an angle of approxi-mately .THETA. to the direction of incidence of the collimated beam.
(a) a source of white light;
(b) an acousto-optic modulator including a transparent medium and a transducer coupled to said medium for generating an acoustical wave in said medium by means of a periodic electrical signal applied to the transducer of a selectable frequency and amplitude;
(c) means for collimating light from said source and directing the collimated beam of said white light onto said medium at a preselected angle .THETA./2 to the perpendicular to the direction of travel of the acoustical wave whereby said light is diffracted by the acoustical wave;
(d) means for selecting a band of the diffracted beam, the midpoint of which band is at an angle of approxi-mately .THETA. to the direction of incidence of the collimated beam.
3. An electronically tuneable light source as defined in claim 2, wherein said periodic electrical signal is sinusoidal and whereby the light emerging from the band will have a wave length and intensity related to the ampli-tude and frequency of the applied sinusoidal electrical signal.
4. An electronically tuneable light source as defined in claim 3, wherein the width of the band of the diffracted light beam is equal to approximately 1/4 of the total width of the visible light which is diffracted.
5. An electronically tuneable light source as defined in claim 1, 3 or 4 wherein the light source is a Xenon arc.
6. An electronically tuneable light source comprising:
(a) a source of white light;
(b) an acousto-optic modulator including a trans-parent medium and a transducer coupled to said medium for generating an acoustical wave in said medium in response to a sinusoidal electrical signal applied to the transducer;
(c) means for simultaneously applying a plurality of sinusoidal waves of generally different amplitudes and frequencies;
(d) means for collimating light from said source and directing the collimated beam of said white light onto said medium at a preselected angle .THETA./2 to the perpendicular to the direction of travel of the acoustical wave whereby said beam is diffracted by the acoustical wave;
(e) means for selecting a band of the diffracted beam the midpoint of which band is at an angle of approximately .THETA. to the direction of incidence of the collimated beam; whereby the light emerging from the band will be a mixture of light components with each component having a wavelength and intensity related to the amplitude and frequency of a corresponding associated sinusoidal wave.
(a) a source of white light;
(b) an acousto-optic modulator including a trans-parent medium and a transducer coupled to said medium for generating an acoustical wave in said medium in response to a sinusoidal electrical signal applied to the transducer;
(c) means for simultaneously applying a plurality of sinusoidal waves of generally different amplitudes and frequencies;
(d) means for collimating light from said source and directing the collimated beam of said white light onto said medium at a preselected angle .THETA./2 to the perpendicular to the direction of travel of the acoustical wave whereby said beam is diffracted by the acoustical wave;
(e) means for selecting a band of the diffracted beam the midpoint of which band is at an angle of approximately .THETA. to the direction of incidence of the collimated beam; whereby the light emerging from the band will be a mixture of light components with each component having a wavelength and intensity related to the amplitude and frequency of a corresponding associated sinusoidal wave.
7. An electronically tuneable light source as defined in claim 6, wherein the light source is a Xenon arc.
8. An electronically tuneable Light source as defined in claim 1, or 2 further including three primary light filters for filtering light from said light source into three respective spectral bands of wavelength .lambda. 1, .lambda. 2 and .lambda. 3 , respectively, before entering said modulator, each filter selectably, removably insertable between said modulator and said light source in response to an external control signal wherein the frequency of said acoustical wave generated in said modulator is selected in accordance with the wavelength of the spectral band of light to be transmitted so as to deflect light of said spectral band through an angle 0.
9. An electronically tuneable light source as defined by claims 3 or 4, further including three primary light filters for filtering light from said light source into three respective spectral bands of wavelengths .lambda.1, .lambda.2 and .lambda.3, respectively, before entering said modulator, each filter selectably, removably insertable between said modu-lator and said light source in response to an external control signal wherein the frequency of the sinusoidal signal applied to said modulator is selected in accordance with the wavelength of the spectral band of light to be transmitted so as to deflect the light of said spectral band through an angle .THETA..
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP82301051A EP0060072A1 (en) | 1981-03-05 | 1982-03-02 | Electronically tuneable light source |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US24099881A | 1981-03-05 | 1981-03-05 | |
| US06/240,998 | 1981-03-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184286A true CA1184286A (en) | 1985-03-19 |
Family
ID=22908814
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000394080A Expired CA1184286A (en) | 1981-03-05 | 1982-01-13 | Electronically tuneable light source |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1184286A (en) |
-
1982
- 1982-01-13 CA CA000394080A patent/CA1184286A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |