Abstract: Primary light is directed to a light path control plate from at least one point-like light source. The light path control plate has an inner face on which projection-like transmission-reflection portions and curved-for-refraction portions are alternately formed along a leaving-direction from an optical axis direction of the point-like light source, wherein each transmission-reflection portion is composed of a transmission face permitting primary light to transmit through the transmission face and a reflection face which reflects the transmitted light as to bring changed light paths directed to an outer face of the light path control plate while each curved-for-refraction portion refracts primary light as to bring changed light paths directed to the outer face of the light path control plate. First light reaching the outer face via the transmission-reflection portions and second light reaching the outer face via the curved-for-refraction portions are generated from primary light.

Abstract: A LCD comprises a surface light source device of side light type for auxiliary lighting. A fluorescent lamp is turned on to supply primary light to be introduced into a guide plate. A back face (upper face) of the guide plate provides a light control face including an emission promoting surface to promote emission from an illumination output face (lower face). The illumination output face provides a specular face without scattering power. Illumination light L2 introduced into the guide plate escapes gradually from the back face and the illumination output face on the way of propagation.

Abstract: A surface light source device comprises a light guide plate 15 having a back face 15E opposite with an emission face, the back face 15 being provided with a great number of micro-reflectors 19 and ridge-like projections 20. A U-shaped fluorescent lamp 14 is disposed along a plurality of end faces 15D, 15E and 15C. Light which is introduced into the light guide plate 15 through the end faces 15D and 15E is direction-converted by the micro-reflectors 19 to be directed to a generally frontal direction end emitted from the emission face. Each micro-reflector 19 realizes direction-conversion mainly through successive double inner-reflections at a pair of slopes. Light introduced into the light guide plate 15 through the end face 15C, which extends in a direction generally perpendicular to the end faces 15D and 15E, is direction-converted by the ridge-like projections 20 having a pair of slopes 20A, 20B to be directed to a generally frontal direction end emitted from the emission face.

Abstract: Provided is a light guide plate having a simple structure that allows an effective emission area to be large and shows a reduced unevenness in brightness in an emission region near to an incidence side face as well as a reduced dropping in brightness in an emission region remote from the incidence side face. The light guide plate is used to provides a surface light source device and an image display employing the device for illuminating an image display panel. In the incidence side face of the light guide plate, a generally central region is formed of a high light dispersing ability area (rough area). The high light dispersing ability area is sandwiched by low light dispersing ability areas (flat and smooth areas or rough areas having a small surface roughness). The high light dispersing ability area is formed in a range including a region irradiated by a center LED of three LEDs.

Abstract: A surface light source device and liquid crystal display are capable of direction-conversion effectively through a double reflections. A back face of a light guide plate 10 is provided with micro-reflectors projecting from a general plane of the back face. A main input light H1 to a micro-reflector 20 is incident to an incidence end face 12 (at point a) and inputted in a somewhat downward inclined direction. An inner input light is inner-reflected mainly by a gently inclined slope 21 (point b) and then impinges on a slope 22 to be reflected again (point c), becoming an inner output light IO. The inner output light IO is emitted from an emission face 13 (point d), being supplied to an LCD panel or the like after transmitting through a light diffusion sheet DF (points e and f). A reflection member RF having an irregular reflectivity, if disposed, recovers light leaking through the slope 22 to use the light efficiently again, thereby providing a reduced fine-unevenness in brightness.

Abstract: A LCD comprises a surface light source device of side light type for auxiliary lighting. A fluorescent lamp is turned on to supply primary light to be introduce into a guide plate. A back face (upper face) of the guide plate provides a light control face including an emission promoting surface to promote emission from an illumination output face (lower face). The illumination output face provides a specular face without scattering power. Illumination light L2 introduced into the guide plate escapes gradually from the back face and the illumination output face on the way of propagation. Some of illumination light emitted from the illumination output face reaches a reflection plate after transmitting a liquid crystal cell and polarization plates. Quantity of light reaching the reflection plate depends on directions of transmission polarization planes of first and second polarization plates as well as state of a liquid crystal layer (depending on voltage applied to transparent electrodes).

Abstract: A surface light source device comprises a light guide plate having an emission face and, opposite with the emission face, a back face which is provided with a great number of micro-reflectors, for example, shaped like pyramids and a fine-unevenness surface is formed among the micro-reflectors. The light guide plate has an incidence face through which an illumination light is introduced into the light guide plate to be then being emitted from the emission face with the help of the micro-reflectors and the fine-unevenness surface. Each micro-reflector has at least a pair of slopes which meet each other as to form a ridge that gets closer with an increasing distance from the incidence face. A large part of an inner propagation light is inner-reflected twice by the slopes successively and direction-converted as to be directed to the emission face.

Abstract: A light control sheet suitable for direction-controlling an angularly extending oblique input light, surface light source device and LCD using the light control sheet. A light control sheet is disposed along an emission face of a light guide plate direction-controls main and subsidiary light fluxes to cause them to be emitted toward a desired direction. Main beam S1 emitted from the emission face transmits (with a small refraction) through a first face, being inner-reflected (total reflection) by a first slope region and then outputted from a light output face (SS1). First subsidiary beam T1 transmits (with a small refraction) through the first face, being inner-reflected (total reflection) by a second slope region and then outputted from the light output face (TT1).

Abstract: A surface light source device and display utilize a light guide plate provided with micro-reflectors arranged in an orientation suitable for a plurality of input portions having point-like light emitters, respectively. A light guide plate 15 has a back face divided into areas ARA to ARC to each of which each input portion having each of LEDs 14A to 14C is shared. Micro-reflectors 19 in each of areas ARA to ARC are orientated as to be directed to each of LEDs 14A to 14C correspondingly, effecting an effective direction conversion. Emitted light is incident to a liquid crystal display panel generally at a right angle via a light diffusion sheet. Some micro-reflectors 19 in each of areas ARA to ARC may be arranged as to be directed to an adjacent input portion. Micro-reflectors may be shaped like quadrangle pyramid projections, cylindrical dents or V-shaped dents.

Abstract: A display has a liquid crystal display panel illuminated by a surface light source device. The surface light source device comprises a primary light source provided with a plurality of point-like light emitters and a light guide plate which is supplied with light by the primary light, the light being introduced in the light guide plate through an incidence face and being emitted through an emission face. The incidence face is located at a corner portion of the light guide plate. A great number of projections for light-advancing-direction-conversion are formed on a back face. Each of the projections includes a pair of slopes formed so as to provide a ridge approaching the back face with an increasing distance from the incidence face. The pairs of slopes form valleys in the light guide plate, the valleys being orientated to be opened toward the corner portion corresponding to the incidence face. Each projection is shaped like, for instance, a quadrangle pyramid.

Abstract: A light guide plate, surface light source device and liquid crystal display of a double-reflection-direction-conversion type have a heightened applicability to an front-lighting arrangement. A back face 14 of a light guide plate 10 is provided with micro-reflectors shaped like trapezoids each of which has a bottom face extending generally in parallel with a general plane of the back face 14. A main input light H10 to a micro-reflector 20 is incident to an incidence end face 12 (at point a) and inputted thereto in a somewhat downward inclined direction. An inner input light is inner-reflected mainly by slopes 21 and 22 successively (at points b and c), becoming an inner output light IO directed to an emission face 13. The inner output light IO is emitted from the emission face 13 (at point d), being supplied to an LCD panel or the like after transmitting through a light diffusion sheet DF (points e and f).

Abstract: A light guide plate provides an emission controlled in three dimensions with little light leaking, being applied to a surface light source device and LCD. The back face is provided with projections each having a pair of faces providing a guiding portion. Orientation of the projections are aligned to a main light coming direction. Input light input to a valley configured as to get narrower and shallower according to distance from the guide portion, then being inside reflected as two slopes successively. Three-dimensionally direction-converted twice, inside output light directed to the emission face is generated. A direction of the output light is controlled through adjusting inclination angles of the slopes. Light introduction from two directions opposite to each other may be done so that the guiding portions are used for direction conversion.

Abstract: A LCD panel is illuminated from its back side by a surface light source device of side light type comprising a guide plate, a primary light source (fluorescent lamp and reflector), a reflection sheet and a prism sheet as a light control member. Light scattering pattern and rough area M are foxed on an emission face of the guide plate. The light scattering pattern consists of a great number of fine light scattering elements. The rough area M is formed among the light scattering elements and has scattering power which is weaker than that of the light scattering elements. The dot-like light scattering elements are distributed according to a certain pattern. This pattern is designed depending on necessity of promotion of emitting. Emitting is promoted in not only portions where the light scattering elements are formed but also in the area M among them. Accordingly, fine periodic bright-dark unevenness and glaring are hard to appear.

Abstract: LEDs 5 serving as light sources are arranged so as to face an incidence surface 4 of a light guide plate 3. Light emitted from the LEDs 5 is incident on the incidence surface 4 of the light guide plate 3 to enter the light guide plate 3 to be propagated through the light guide plate 3. When the angle of incidence of the light on an emission surface 6 of the light guide plate 3 is a critical angle or less while the light is propagated, the light leaves the emission surface 6. On at least one of the emission surface 6 of the light guide plate 6 and a surface 10 opposite to the emission surface 6 of the light guide plate 6, a large number of prism protrusions 12 extending in parallel to such a direction that a distance from the incidence surface 4 increases are formed along the incidence surface 4. A side-face side portion 10b of the prism protrusions 12 is formed so as to have a height gradually decreasing as a distance from the incidence surface 4 decreases.

Abstract: A surface light source device and liquid crystal display are capable of direction-conversion effectively through a double reflections. A back face of a light guide plate 10 is provided with micro-reflectors projecting from a general plane of the back face. A main input light H1 to a micro-reflector 20 is incident to an incidence end face 12 (at point a) and inputted in a somewhat downward inclined direction. An inner input light is inner-reflected mainly by a gently inclined slope 21 (point b) and then impinges on a slope 22 to be reflected again (point c), becoming an inner output light IO. The inner output light IO is emitted from an emission face 13 (point d), being supplied to an LCD panel or the like after transmitting through a light diffusion sheet DF (points e and f). A reflection member RF having an irregular reflectivity, if disposed, recovers light leaking through the slope 22 to use the light efficiently again, thereby providing a reduced fine-unevenness in brightness.

Abstract: A surface light source device and LCD provide a visual angle highly uniform two-dimensionally and reduced fine brightness unevenness, utilizing a light guide plate. The surface light source device illuminating an LCD panel employs a light guide plate having a back face 34 provided with many micro-reflectors 20. Beams P1, P2 representing an inner input light is inner-reflected by a slope 21 and then by another slope 22 or 22 and then 21, becoming an inner out light Q1, Q2 proceeding toward an emission face 33. Postures of micro-reflectors 20 are deviated from a standard posture on x-axis, y-axis and z-axis, respectively, thereby causing beams Q1, Q2 to inner-impinge to the emission face 33 at proceeding directions which are different three-dimensionally from each other. This difference is amplified through refraction at emission from the emission face 33.

Abstract: A surface light source device and LCD employing light guide plates having inconspicuous micro-reflector arrays are provided. Alight guide plate 30 illuminating an LCD panel of a surface light source device has a back face 32 provided with many micro-reflectors 20 arranged with sidewise intervals on imaginary lines Ki which are generally perpendicular to an imaginary reference line S with longitudinal intervals getting smaller according to an increasing distance from an incidence face 33. On each imaginary line Ki, the sidewise intervals get smaller or micro-reflector sizes get larger according to an increasing distance from the reference line S. Making many microreflector trios each of which consists of micro-reflectors arranged adjacent to each other and on any imaginary lines Ki to Ki+2, each of the trios has micro-reflectors are located generally on a straight line. Covering rate of the micro-reflectors increases according to an increasing distance from an incidence face 33.

Abstract: Provided are surface light source devices and LCDs having isotropic and wide viewing angles. A surface light source device for illuminating an LCD comprises a light guide plate hiving a back face provided with a great number of micro-reflectors. Light beams P1, P2 representing an inner input light are inner-reflected by first and then second inner reflection faces or in inverse order, respectively to become a first and second inner output lights Q1 and Q2 which are non-parallel to each other, providing an emission having angular intensity characteristics showing two peaks. Peak splitting of the emission is dissolved by a light diffusion sheet disposed along an emission face of the light guide plate, causing an LCD panel to be illuminated by an isotropic and wide-view-angled illumination output light.

Abstract: Cylindrically curved slopes successively inner-reflect illumination light which reaches a back face or emission face of a light guide plate via an upper edge of an incidence face. The curved slopes give the light diverse propagation directions after inner-reflection. This avoids the viewer from observing a strongly irradiated edge, thereby reducing reflective appearance. Inner-reflection by the curved slopes also gives diverse propagation directions to illumination light coming via other edges, thereby reducing reflective appearance. Curved surface profile is given to valleys involved in a great number of projection rows running in a direction approximately perpendicular to the incidence face, and may be further given to the projection rows. The valleys are provided with curved surface profile within a curved-surface-profile-giving-area around the incidence face or, in addition to this, around flank faces of the light guide plate.

Abstract: A guide plate has a major face on which projections are arranged, wherein the projections have an arch-like profile within the vicinity of an incidence end face, or, in addition to this, within regions along both side end faces, thereby preventing the guide plate from producing abnormal brightness which could be caused by reflective appearance of edges. A primary light source is disposed beside the guide plate. Major faces of the guide plate provide an emission face and a back face. A prism sheet and a protection sheet are disposed along the emission face. A liquid crystal display panel is additionally arranged to provide a liquid crystal display. The guide plate has a wedge-shaped cross section and a minor face at its thicker end provides the incidence end face along the primary light source. The emission face may be provided with light scattering pattern to promote emission.