Optical head

Claim 2

An optical head for focusing and projecting a laser light beam, adapted to focus a laser light spot on an optical recording medium (6) for recording, reproducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least three end surfaces, said optical wave guide being formed of a material, which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and said optical wave guide being provided with an optical system including a collimator lens (14), a beam splitter (3) and an objective lens (15) and a sensor lens (17) located besides the beam splitter (3); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for emitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); electro-acoustic transducer (18a, 18b, 18c, 18d, 18e, 18f) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by ultra-sonic vibration for producing surface acoustic wave in said optical wave guide (12), which gives rise to a condensation and rarefaction distribution in refractive index in said optical wave guide (12) influencing the direction of transmission of said light beam passing therethrough; a semiconductor photosensor (10) disposed at another end surface of said optical wave guide (12) in opposition to said sensor lens (17), said photosensor (10) detecting reflected light of said light beam projected and focused on said optical recording medium in cooperation said objective lens (15), said beam splitter (3) and said sensor lens (17); and means for regulating said ultra-sonic vibration, depending on the output of said photsensor (10).

Claim 3

An optical head according to Claim 1, wherein said material which causes the condensation and rare­faction distribution in refractive index is a material having a piezo-electric effect and said electro-acoustic transducer (18a, 18b, 18c, 18d, 18e, 18f) is constituted by interdigital electrodes.

Claim 4

An optical head according to Claim 1, wherein said material which causes the condensation and rare­faction distribution in refractive index is a material having no piezo-electric effect and said electro-acoustic transducer (18a, 18b, 18c, 18d, 18e, 18f) is constituted by interdigital electrodes and a material which itself vibrates.

Claim 5

An optical head according to Claim 1, further comprising a circuit for synchronizing the drive of said transducer (18a, 18b, 18c, 18d) by ultra-sonic vibration and the light emitted by said laser light source (13), this circuit having a function that the light is emitted by said laser light only when the condensation and rarefaction distribution in refractive index in said optical wave guide (12) are in a prede­termined form.

Claim 6

An optical head for focusing and projecting a laser light beam adapted to focus a laser light spot on an optical recording medium (6) for recording, reproducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least one end surfaces, said optical wave guide being formed of a material, which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and said optical wave guide being provided with an optical system including a collimator lens (14) and an objective lens (15); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for emitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); and electro-acoustic transducer (18e, 18f) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corresponding to a half period of a sine curve, across a path of said light beam formed in said optical wave guide (12), which gives rist to a form of the half period of a sine curve condensation and rarefraction distribution in refractive index in said optical wave guide (12), thereby giving a function of lens for the light beam passing therethrough with a variable focal position controlled by varying the amplitude of said ultra-sonic vibration.

Claim 7

An optical head for focusing and projecting a laser light beam adapted to focus a laser light spot on an optical recording medium (6) for recording, reproducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least one end surfaces, said optical wave guide being formed of a material, which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and said optical wave guide being provided with an optical system including a collimator lens (14) and an objective lens (15); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for emitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); and electro-acoustic transducer (18e, 18f) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corresponding to a half period of a sine curve, across a path of said light beam formed in said optical wave guide (12), which gives rist to a form of the half period of a sine curve condensation and rarefraction distribution in refractive index in said optical wave guide (12), thereby giving a function of lens for the light beam passing therethrough with a variable focal position controlled by varying the amplitude of said ultra-sonic vibration.

Claim 8

An optical head according to Claim 5, further comprising a circuit for synchronizing the drive of said transducer (18e, 18f) by ultra-sonic vibration and the light emitter by said laser light source (13), wherein the light is emitted by said laser light only when the condensation and rarefaction distribution in refractive index in said optical wave guide (12) are in a predetermined form.

Claim 9

An optical head for focusing and projecting a laser light beam adapted to focus a laser light spot on an optical recording medium (6) for recording, reproducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least one end surfaces, said optical wave guide being formed of a material which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and an optical wave guide being provided with an optical system including a collimator lens (14) and an objective lens (15); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for exmitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); first electro-acoustic transducer (18e, 18f) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by a first ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corresponding to a half period of a sine curve, across a path of said light beam formed in said optical wave guide (12), which gives rise to a form of the half period of a sine curve condensation and rare­faction distributyion in refractive index in said optical wave guide (12), thereby giving a function of lens for the light beam passing therethough with avariable focal position controlled by varying the amplitude of said ultra-sonic vibration; and second electro-acoustic transducer (18c, 18d) disposed between said beam splitter (3) and said objective lens (15), said transducer being adpated to be driven by a second ultra-sonic vibration for pro­ducing ultra-sonic surface acoustic waves across a path of said light beam formed in said optical wave guide (2), which gives rise to a form of grating-pattern condensation and rarefaction distribution in refractive index in said optical wave guide (12), thereby giving a function of diffracting grating for the light beam passing therethrough, the direction of transmission of said light beam being able to be varied, by varying the frequency of said second ultra-sonic vibration.

Claim 10

An optical head for focusing and projecting a laser light beam adapted to focus a laser light spot on an optical recording medium (6) for recording, reproducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least one end surfaces, said optical wave guide being formed of a material which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and an optical wave guide being provided with an optical system including a collimator lens (14) and an objective lens (15); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for exmitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); first electro-acoustic transducer (18e, 18f) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by a first ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corresponding to a half period of a sine curve, across a path of said light beam formed in said optical wave guide (12), which gives rise to a form of the half period of a sine curve condensation and rare­faction distributyion in refractive index in said optical wave guide (12), thereby giving a function of lens for the light beam passing therethough with avariable focal position controlled by varying the amplitude of said ultra-sonic vibration; and second electro-acoustic transducer (18c, 18d) disposed between said beam splitter (3) and said objective lens (15), said transducer being adpated to be driven by a second ultra-sonic vibration for pro­ducing ultra-sonic surface acoustic waves across a path of said light beam formed in said optical wave guide (2), which gives rise to a form of grating-pattern condensation and rarefaction distribution in refractive index in said optical wave guide (12), thereby giving a function of diffracting grating for the light beam passing therethrough, the direction of transmission of said light beam being able to be varied, by varying the frequency of said second ultra-sonic vibration.

Claim 11

An optical head according to Claim 7, wherein said grating-pattern condensation and rarefaction distribution in refractive index is formed by said standing wave.

Claim 12

An optical head according to Claim 7, wherein said grating-pattern condensation and rarefaction distribution in refractive index is formed by a travel­ling wave of said ultra-sonic surface acoustic wave.

Claim 13

An optical head according to Calim 7, further comprising a circuit for synchronizing the drive of said transducer (18e, 18f) by ultra-sonic vibration and the light emitted by said laser light source (13), wherein the light is emitted by said laser light only when the condensation and rarefaction distribution in refractive index in said optical wave guide (12) are in a predetermined form.

Claim 14

An optical head according to Calim 7, further comprising a circuit for synchronizing the drive of said transducer (18e, 18f) by ultra-sonic vibration and the light emitted by said laser light source (13), wherein the light is emitted by said laser light only when the condensation and rarefaction distribution in refractive index in said optical wave guide (12) are in a predetermined form.

Claim 15

An optical head for focusing and projecing a laser light beam, adpated to focus a laser light spot on a light recording medium (6) for recording, repro­ducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least one end surfaces, said optical wave guide being formed of a material which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and said optical wave guide being provided with an optical system including a collimator lens (14) and an objective lens (15); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for emitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); and electro-acoustic transducer (18a, 18b) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by a first ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corre­sponding to a half period of a sine curve, across a path of said light beam formed in said optical wave guide (12), which gives rise to a form of the half period of a sine curve condensation and rarefaction distribution in refractive index in said optical wave guide (12), thereby giving a function of lens for the light beam passing therethrough with a variable focal position controlled by varying the amplitude of said ultra-sonic vibration, and said transducer being adapted to be driven by a second ultra-sonic vibration for producing ultra-­sonic surface acoustic waves across a path of said light beam formed in said optical wave guide (12), which gives rise to a form of grating-pattern condensation and rarefaction distribution in refractive index in said optical wave guide (12), thereby giving a function of diffracting grating for the light beam passing therethrough, the direction of transmission of said light beam being able to be varied, by varying the frequency of said second ultra-sonic vibration.

Claim 16

An optical head for focusing and projecing a laser light beam, adpated to focus a laser light spot on a light recording medium (6) for recording, repro­ducing and erasing information, comprising: a plate-shaped optical wave guide (12) having at least one end surfaces, said optical wave guide being formed of a material which is capable of establishing condensation and rarefaction in refractive index by a surface acoustic wave, and said optical wave guide being provided with an optical system including a collimator lens (14) and an objective lens (15); a laser light source (13) disposed at one of the end surfaces of said optical wave guide (12) for emitting a laser light beam, light emitted by said laser light source (13) adapted to be directed in the form of a light beam to said optical recording medium (6); and electro-acoustic transducer (18a, 18b) disposed between said beam splitter (3) and said objective lens (15), said transducer being adapted to be driven by a first ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corre­sponding to a half period of a sine curve, across a path of said light beam formed in said optical wave guide (12), which gives rise to a form of the half period of a sine curve condensation and rarefaction distribution in refractive index in said optical wave guide (12), thereby giving a function of lens for the light beam passing therethrough with a variable focal position controlled by varying the amplitude of said ultra-sonic vibration, and said transducer being adapted to be driven by a second ultra-sonic vibration for producing ultra-­sonic surface acoustic waves across a path of said light beam formed in said optical wave guide (12), which gives rise to a form of grating-pattern condensation and rarefaction distribution in refractive index in said optical wave guide (12), thereby giving a function of diffracting grating for the light beam passing therethrough, the direction of transmission of said light beam being able to be varied, by varying the frequency of said second ultra-sonic vibration.

Claim 17

An optical head according to Claim 11, wherein said optical wave guide (12) producing the conden­sation and rarefaction distribution in refractive index is formed of a material having a piezo-electric effect and said electro-acoustic transducer (18a, 18b) is constituted by interdigital electrodes.

Claim 18

An optical head according to Claim 11, wherein said optical wave guide (12) producing condensation and rarefaction distribution in refractive index is formed of a material having no piezo-electric effect and said electro-acoustic transducer (18a, 18b) is constituted by interdigital electrodes and a material which itself vibrates.

Claim 19

An optical head according to Claim 11, further comprising a circuit for synchronizing the drive of said transducer (18a, 18b) by ultra-sonic vibration and the light emitted by said laser light source (13), wherein the light is emitted by said laser light only when the condensation and rarefaction distribution in refractive index in said optical wave guide (12) are in a predetermined form.

Claim 20

Optical means, comprising: a plate-shaped optical wave guide (12), said optical wave guide being formed of a material which is capable of establishing a condensation and rare­faction distribution in refractive index by a surface acoustic wave; electro-acoustic transducer (18e, 18f) located to produce a surface acoustic wave which transverses an optical path in said optical wave guide (12); ultra-sonic wave generator (19-2) driving said electro-acoustic transducer (18e, 18f), said transducer being adapted to be driven by ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corresponding to a half period of a sine curve, across said optical path in said optical wave guide (12), which gives rise to a form of the half period of a sine wave condensation and rare­faction distribution in refractive index in sais optical wave guide (12), the distribution acting on the light beam passing therethrough as a lens with a variable focal position controlled by varying the amplitude of said ultra-sonic vibration.

Claim 21

Optical means, comprising: a plate-shaped optical wave guide (12), said optical wave guide being formed of a material which is capable of establishing a condensation and rare­faction distribution in refractive index by a surface acoustic wave; electro-acoustic transducer (18e, 18f) located to produce a surface acoustic wave which transverses an optical path in said optical wave guide (12); ultra-sonic wave generator (19-2) driving said electro-acoustic transducer (18e, 18f), said transducer being adapted to be driven by ultra-sonic vibration for producing a standing wave of an ultra-sonic surface acoustic wave corresponding to a half period of a sine curve, across said optical path in said optical wave guide (12), which gives rise to a form of the half period of a sine wave condensation and rare­faction distribution in refractive index in sais optical wave guide (12), the distribution acting on the light beam passing therethrough as a lens with a variable focal position controlled by varying the amplitude of said ultra-sonic vibration.