Abstract: A light emitting apparatus comprising: a light guiding member that projects light, that is incident on an end face thereof, through a principal plane; and a plurality of light emitting diodes that are optically coupled with the end face, wherein the light guiding member has a protruding surface formed in part of the end face thereof and comprises a first light introducing portion that is formed on the protruding surface and is optically coupled to a first light emitting diode, and a second light introducing portion that is optically coupled to a second light emitting diode and is formed on the rest of the end face, and the first and second light emitting diodes are capable of emitting color-blended light having two or more peaks in the spectrum.

Abstract: A coherent beam is converted into a light flux having an expanded width at a predetermined position closer to a photosensitive element. Part of the expanded light flux is irradiated directly on the photosensitive element as a reference beam. The remainder of the expanded light flux is diffused, and its optical direction is changed. Thus, the remainder of the expanded light flux not irradiated directly to the photosensitive element is converted into a scattered beam advancing as an object beam toward the photosensitive element. Interference fringes are formed on the photosensitive element by using the reference beam and the object beam.

Abstract: Method for producing a of a transparent type hologram screen of an wide visible range. A photosensitive member and a light source of a reference light are arranged on the same side of the light diffusing body. A light source of an object light is arranged on the opposite side of the light diffusing body, so that the light is transmitted through the light diffusing body to generate a object light. A light from a light source of a reference light is reflected at the light diffusing body or a member such as a half mirror or a transparent, reflective hologram element arranged at a front side of the light diffusing body.

Abstract: A head-up display includes a projector which projects an image light and a hologram lens which diffracts and reflects the projected image and form a virtual image located ahead of a windshield. The hologram lens has a vertical diffraction characteristic which is equivalent to a hyperbolic or parabolic-curve mirror along a line formed by the intersection of the hologram lens and a vertical plane which includes an axis of the image light and a horizontal diffraction characteristic which is equivalent to a parabolic or elliptic curve mirror along a line which is formed by the intersection of the hologram lens and a horizontal plane which includes the axis of the image light. When the hologram is directly attached on a curved windshield which has a focal length fs (in case it is a mirror), the focal length fo of the hologram and the former focal length fs has the following relationship; 1/fo=1/fh+1/fs, where fh is a focal point when the hologram is flat.

Abstract: Disclosed is a method for producing an optical member having excellent optical characteristics. An optical member is composed of a support plate and an optical sheet stuck on said plate via an optical adhesive. The optical adhesive is made sticky after it is coated, including ultraviolet-curing adhesives, epoxy adhesives and their mixtures. To produce the optical member, the optical sheet is formed on the surface of a fixed substrate via a transfer film. The optical adhesive is coated onto the optical sheet, the adhesive is made sticky on the sheet, the fixed substrate is peeled off, the sheet is stuck onto the support plate using the adhesive, and the adhesive is cured.