Abstract: A projection lens unit includes a main body; a lens fixed to the main body; and a hood disposed to one end of the main body close to a screen. The hood defines the outermost boundary of a view angle stretching with respect to the center of the lens and includes a light-shielding plate and a light-shielding barrel. When the shielding height of the light-shielding plate and the length of the light-shielding barrel are respectively represented by H and L, the shielding height H and the length L are set so as to satisfy the equation tan(?/2)=H/L, in relation to the view angle ?. More particularly, these dimensions are set so as to satisfy the condition that the ratio H/L lies in a range from 0.74 to 0.94. The inner surface of the light-shielding barrel is subjected to surface treatment so as to absorb unnecessary light thereby, reflect it thereat, or scatter it thereat. To be more specific, the light-shielding barrel has scattering grooves disposed on the inner surface thereof.

Abstract: A projection lens unit compensates for thermal expansion and contraction. The unit comprises a coupler at the front surface of a CRT, a lens unit body for projecting an image onto a screen by controlling and magnifying the light from the CRT, a plurality of legs secured to the coupler for supporting the lens unit body at more than three points, a slide mechanism (latch arms and latch engaging slots provided between the legs and the lens unit body for slidably supporting the legs for movement along the optical axis relative to the lens unit body, and expansion/contraction bars provided between the legs and the lens unit body for compensating for the thermally induced expansion/contraction, with one end engaged with a leg and the other end engaged with the base of the lens unit body.

Abstract: A projection lens, for enlarging and projecting a picture formed on a flat fluorescent plate of a CRT projection tube, includes: a first lens unit of a plus lens, having aspheric surfaces on both surfaces, being convex to the screen side at a central portion including an optical axis, a second lens unit of a minus lens, having aspheric surfaces on both surfaces, being concave to the screen side at a central portion including an optical axis; a third lens unit of a plus lens, having spherical surfaces on both surfaces, being convex on both sides; a fourth lens unit of a plus lens, having aspheric surfaces on both surfaces thereof, being curved in concave-like to the screen side, on a peripheral portion far from the optical axis into a radial direction; and a fifth lens unit of a minus lens, being made up with a transparent liquid, commonly serving a faceplate of the CRT projection tube and a cooling, and a meniscus lens, having a thickness being nearly equal to and at least an aspheric surface directing a conc

Abstract: An object of the present invention is to suppress an influence due to temperature change and various aberrations. It is a projection lens which projects an image on a surface of a screen (magnified side). A first group I having a negative refractive power and a second group II having a positive refractive power are arranged in order from a magnified side toward a reduced side. The first group I is configured to arrange a first lens and a second lens in order from the magnified side, and the second group II is configured to arrange a third lens to a seventh lens. The first and second lenses are a negative meniscus lens whose both surfaces are formed by the aspherical surface in which an area near an optical axis of the surface on the magnified side is a concave surface. The third lens is a cemented lens in which a bi-concave lens is cemented to the surface on the reduced side of a bi-convex lens.

Abstract: Sealing is securely performed according to a change caused by thermal expansion and contraction, dust and the like are prevented from intruding, and degradation of image quality is protected. A single lens 11 or the plural lenses 11 are mounted into a cylinder portion in a projection lens unit, and the projection lens unit magnifies and projects an image and the like on a light source side onto a screen. The projection lens unit includes an O-ring 17 which seals a gap by permitting a change in gap generated when the cylinder portion is expanded and contracted according to temperature change caused by heat of the light source. The cylinder portion includes an inner lens-barrel 12 which supports the lens 11 and an outer lens-barrel 13 which slidably supports the inner lens-barrel 12, and the cylinder portion also includes a coupler unit 4 connecting the outer lens-barrel 13 onto the light source side.

Abstract: A color image projecting device includes an illuminating optical system and a projection optical system. The illuminating optical system includes a light source emitting white light including red, green, and blue colors, a dividing-spectra block having reflecting surfaces reflecting the red and blue colors of the light received from the light source toward left and right while transmitting the green color, a red block having a dichroic mirror provided in contact with the dividing-spectra block and reflecting the red color, reflected off the reflecting surface of the dividing spectra block, toward the projection optical system, a blue color block having a dichroic mirror like that of the red block, and a green block having a dichroic mirror reflecting the transmitted green color of light toward the projection optical system.

Abstract: A projection lens, for enlarging and projecting a picture formed on a flat fluorescent plate of a CRT projection tube, comprising: a first lens unit of a plus lens, having aspheric surfaces on both surfaces thereof, being convex to the screen side at a central portion including an optical axis thereof; a second lens unit of a minus lens, having aspheric surfaces on both surfaces thereof, being concave to the screen side at a central portion including an optical axis thereof; a third lens unit of a plus lens, having spherical surfaces on both surfaces thereof, being convex on both sides; a fourth lens unit of a plus lens, having aspheric surfaces on both surfaces thereof, being curved in concave-like to the screen side, on a peripheral portion far from the optical axis into a radial direction thereof; and a fifth lens unit of a minus lens, being made up with a transparent liquid, commonly serving a faceplate of the CRT projection tube and a cooling, and a meniscus lens, having a thickness being nearly equal to

Abstract: An object of the present invention is to suppress an influence due to temperature change and various aberrations. It is a projection lens which projects an image on a surface of a screen (magnified side). A first group I having a negative refractive power and a second group II having a positive refractive power are arranged in order from a magnified side toward a reduced side. The first group I is configured to arrange a first lens and a second lens in order from the magnified side, and the second group II is configured to arrange a third lens to a seventh lens. The first and second lenses are a negative meniscus lens whose both surfaces are formed by the aspherical surface in which an area near an optical axis of the surface on the magnified side is a concave surface. The third lens is a cemented lens in which a bi-concave lens is cemented to the surface on the reduced side of a bi-convex lens.

Abstract: A projection lens unit includes a main body; a lens fixed to the main body; and a hood disposed to one end of the main body close to a screen. The hood defines the outermost boundary of a view angle stretching with respect to the center of the lens and includes a light-shielding plate and a light-shielding barrel. When the shielding height of the light-shielding plate and the length of the light-shielding barrel are respectively represented by H and L, the shielding height H and the length L are set so as to satisfy the equation tan(&agr;/2)=H/L, in relation to the view angle &agr;. More particularly, these dimensions are set so as to satisfy the condition that the ratio H/L lies in a range from 0.74 to 0.94. The inner surface of the light-shielding barrel is subjected to surface treatment so as to absorb unnecessary light thereby, reflect it thereat, or scatter it thereat. To be more specific, the light-shielding barrel has scattering grooves disposed on the inner surface thereof.

Abstract: A projection lens unit, which is small, compatible and highly capable of compensating for the changes in temperature, is provided. The unit comprises a coupler 5 provided at the front surface of a CRT 1, a lens unit body 6 for projecting an image onto a screen by controlling and magnifying the light from the CRT 1, a plurality of leg portions 7 secured to the coupler 5 for supporting the lens unit body 6 at more than three points, a slide mechanism (latches 58 and latch engaging slots 42) provided between the leg portions 7 and the lens unit body 6 for slidably supporting the leg portions 7 in the direction of optical axis in relation to the lens unit body 6, and an expansion/contraction bars 8 provided between the leg portions 7 and the lens unit body 6 for compensating for the effect of heat with one end engaged with the tip end side of the leg portions 7 and the other end with the base end side of the lens unit body 6.

Abstract: Decreasing the number of components and assembly processes for improving assembly efficiency and reducing production cost is promoted. A color image projecting device 31 comprises an illuminating optical system 32 and a projection optical system 33. The illuminating optical system 32 comprises a light source emitting white light including red, green, and blue colors, a dividing-spectra block 35 having reflecting surface 35A and 35B reflecting the red and blue colors in three colors of light from the light source toward left and right while transmitting a green color of light, a red block 36 having a dichroic mirror 36A provided in contact with the dividing-spectra block 35 and reflecting a red color of light reflected off the reflecting surface 35A toward the projection optical system 33, a blue color block 38 having a dichroic mirror 38A like the red block 36, and a green block 37 having a dichroic mirror 37A reflecting a transmitted green color of light toward the projection optical system 33.

Abstract: A lens apparatus for projection includes a plurality of lenses on an optical axis. A shading plate 11 for covering the peripheral portion of the lens to block off light entering the peripheral portion is provided as a single member on the optical axis with the lenses to omit an inking process. In addition, the shading plate 11 is integrally provided with a contrast compensating plate 13 for compensating a projected image, so that it is not required to provide any portions for supporting the contrast compensating plate 13. Moreover, a shading wall 23 for blocking off light leaking out of the peripheral portion of the lens is provided on the peripheral portion of the shading plate 11. Thus, it is possible to provide a lens apparatus for projection, which has a simple structure and which can be easily assembled to reduce the producing costs.

Abstract: A lens apparatus for projection includes a plurality of lenses on an optical axis. A shading plate 11 for covering the peripheral portion of the lens to block off light entering the peripheral portion is provided as a single member on the optical axis with the lenses to omit an inking process. In addition, the shading plate 11 is integrally provided with a contrast compensating plate 13 for compensating a projected image, so that it is not required to provide any portions for supporting the contrast compensating plate 13. Moreover, a shading wall 23 for blocking off light leaking out of the peripheral portion of the lens is provided on the peripheral portion of the shading plate 11. Thus, it is possible to provide a lens apparatus for projection, which has a simple structure and which can be easily assembled to reduce the producing costs.

Abstract: A lens apparatus for projection includes a plurality of lenses on an optical axis. A shading plate 11 for covering the peripheral portion of the lens to block off light entering the peripheral portion is provided as a single member on the optical axis with the lenses to omit an inking process. In addition, the shading plate 11 is integrally provided with a contrast compensating plate 13 for compensating a projected image, so that it is not required to provide any portions for supporting the contrast compensating plate 13. Moreover, a shading wall 23 for blocking off light leaking out of the peripheral portion of the lens is provided on the peripheral portion of the shading plate 11. Thus, it is possible to provide a lens apparatus for projection, which has a simple structure and which can be easily assembled to reduce the producing costs.

Abstract: The prism assembly of the present invention includes: a prism made of plastics having light transmittivity; and a glass plate which is joined to a plane of the prism obliquely intersecting a light incidence plane of the prism and whose one surface carries a dichroic layer formed thereon.

Abstract: The laser pointer of this invention includes: a laser pointer main body for emitting a visible laser beam; and a deflection optical element disposed on the central axis of the laser beam and adapted to deflect the direction along which the emitted laser beam passes.

Abstract: This projection lens for a projection television includes coaxially in order towards the face plate of the CRT: a first lens of negative power, both of whose surfaces are aspherical; a second lens of positive power, at least one of whose surfaces is aspherical, formed of a plastic material; a third lens of positive power; a fourth lens of positive power, at least one of whose surfaces is aspherical, formed of a plastic material; and a back lens of negative power, which presents in the direction away from the face plate of the CRT a face of strongly concave curvature. The third lens is the strongest of the lenses in absolute power, and the second lens and the fourth lens have substantially the same optical characteristics, and are disposed in reverse orientation on opposite sides of the third lens. Certain conditions relating to lens parameters should be satisfied for acceptable optical performance.