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US 2006/0131491 A1Published application
Optical scanning apparatus and image forming apparatus employing this apparatus
AssigneeCanon Kabushiki Kaisha
InventorsHidekazu Shimomura, Ken Tanimura, Hiroshi Sato, Tokuji Takizawa
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Abstract
At least one exemplary embodiment is directed to an optical scanning apparatus that employs a short wave light source to constantly maintain a spot having a tiny diameter, even when an environmental temperature change occurs, by employing a lens and/or a diffractive optical element.
Claims29
An optical scanning apparatus comprising:
- a light source;
- a deflection unit configured to deflect a light flux emitted by the light source;
- a first optical system configured to condense, at the deflection unit, a divergent light flux emitted by the light source;
- a second optical system configured to focus, on a target scanning face, the light flux deflected by the deflection unit,
- wherein the wavelength of the light flux emitted by the light source is 450 nm or shorter,
- wherein a first refractive optical element made of plastic is arranged in the second optical system, and a first diffractive optical element having a diffraction surface is arranged in the first optical system, and
- wherein power for the first refractive optical element in a main scanning direction and power for the diffraction surface of the first diffractive optical element in the main scanning direction have the same sign.
4 more elements
An optical scanning apparatus comprising:
- a light source;
- a deflection unit, configured to deflect a light flux emitted by the light source;
- a first optical system, which includes a second refractive optical element that includes at the least one lens that condenses, toward the deflection unit, divergent light flux emitted by the light source;
- and
- a second optical system, which includes a first refractive optical element_made of plastic configured to focus, on a target scanning face, a light flux deflected by the deflection unit,
- wherein a wavelength of a light flux emitted by the light source is equal to or shorter than 450 nm,
- wherein a first diffractive optical element having a diffraction surface is located in the first optical system,
- wherein power for the first refractive optical element in a main scanning direction and power for the diffraction surface of the first diffractive optical element in the main scanning direction have the same sign,
- wherein, when synthesis power in a main scanning direction for the first optical system is denoted by φ, and power in a main scanning direction for an i-th lens that constitutes the second refractive optical element is denoted by φi, the refractive index of the i-th lens that constitutes the second refractive optical element is denoted by ni, a refractive index wavelength change rate for the i-th lens that constitutes the second refractive optical element is denoted by dni/dλ, the power for the diffraction surface of the first diffractive optical element in the main scanning direction is denoted by φdo, an imaging magnification of the optical scanning apparatus in the main scanning direction is denoted by β and an emission F number for the second optical system in the main scanning direction is denoted by FNo. satisfies,
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52 more elements
An optical scanning apparatus comprising:
- a light source;
- a deflection unit configured to deflect a light flux emitted by the light source;
- a first optical system configured to condense, at the deflection unit, a divergent light flux emitted by the light source;
- a second optical system configured to focus, on a target scanning face, the light flux deflected by the deflection unit,
- wherein the wavelength of the light flux emitted by the light source is 450 nm or shorter,
- wherein a first refractive optical element made of plastic is arranged in the second optical system, and a second refractive optical element is arranged in the first optical system, and
- wherein power for the first refractive optical element in a main scanning direction and power for the second refractive optical element in the main scanning direction have the different sign.
4 more elements
An optical scanning apparatus comprising:
- a light source;
- a deflection unit, configured to deflect a light flux emitted by the light source;
- a first optical system, which includes a third refractive optical element having at least one lens configured to condense, toward the deflection unit, a divergent light flux emitted by the light source;
- and
- a second optical system, which includes a first refractive optical element made of plastic configured to focus, on a target scanning face, the light flux deflected by the deflection unit,
- wherein a wavelength of the light flux emitted by the light source is 450 nm or shorter,
- wherein a second refractive optical element made of plastic is arranged in the first optical system,
- wherein power for the first refractive optical element in a main scanning direction and power for the second refractive optical element in the main scanning direction have the different sign,
- wherein, when synthesis power in the main scanning direction for the first optical system is denoted by φ, and the power in the main scanning direction for an i-th lens that constitutes the third refractive optical element is denoted by φi, the refractive index for the i-th lens that constitutes the third refractive optical element is denoted by ni, the change rate for the refractive index relative to the wavelength of the i-th lens that constitutes the third refractive optical element is denoted by dni/dλ, the power in the main scanning direction for a k-th lens that constitutes the second refractive optical element in the main scanning direction is denoted by φk, the change rate for the refractive index relative to the wavelength of the k-th lens that constitutes the second refractive optical element is denoted by dnk/dλ, an imaging magnification for the optical scanning apparatus in the main scanning direction is denoted by β and an emission F number for the second optical system in the main scanning direction is denoted by FNo. satisfies,
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- 1
- ϕ
- 2
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- ⅆ
- n
- i
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- 10
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- 6
64 more elements
Dependencies are inferred from the claim text.