Enplas Corporation

Other

Kazumasa Ohsumi

Shingo Ohkawa

Kazuo Suzuki

Kayoko Masaki

LCD panelis mounted on surface light source deviceoutputting an oblique preferential emission under emission promotion by scattering pattern formed on emission faceC. Back faceB provides a light control face correcting directivity toward a frontal direction in a plane parallel to incidence end faceA. Directivity is further corrected toward a frontal direction in a plane perpendicular to faceA by a prism sheetwhich is coupled with panelto provide a composite optical element unified with a polarization film. Output light from liquid crystalimpinges onto a polarization film. Light component corresponding to a transmission polarization plane of polarization filmis outputted out of the device after being transmitting film. Prism sheetmay be coupled with another member like polarization separating sheet member. Prism projection rows avoid from being damaged or deformed.

Liquid crystal display panel, liquid crystal display device and composite optical element

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 Lintroduced into the guide plate escapes gradually from the back face and the illumination output face on the way of propagation.

Surface light source device of side light type and liquid crystal display

A liquid crystal display includes a surface light source device of a side light type for lighting. On lighting a fluorescent lamp, primary light is introduced into a guide plate and propagates within the guide plate. Much of the illumination light enters into any one of a number of ridges on an emission-function face, being followed by inner impingement upon a flank face, which is more remote from an incidence end face, at an entry angle greater than a critical angle &thgr; 1. Much of the light which has undergone such inner impingement is supplied to a liquid crystal display panel almost frontward via a top face. The ridges are inclined at a predetermined inclination angle &agr; with respect to the incidence end face of the guide plate. Inclination angle &agr; preferably falls within a range from 5 degrees to 45 degrees, in particular, from 15 degrees to 30 degrees. Employment of size-reduced ridges is realizable, leading to less conspicuous ridges without reducing emission function. Moire fringes are preventable, too. Each ridge may be provided with all or some of a tapered shape, an inclined flank face and foot portions with a stepwise difference.

Guide plate, surface light source device of side light type and liquid crystal display

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 L 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). The reflection plate reflects and scatters illumination output light. Some of thus reflected and scattered illumination output light is emitted out of the device after transmitting a polarization plate, the liquid crystal cell, the guide plate and another polarization plate in order, thereby contributing to displaying. The light control face (back face) is provided with emission promoting property to promote escaping of light L from the illumination output face. This emission promoting property is provided so as to be once getting stronger according to distance from an incidence end face A and to be followed by getting weaker. In another arrangement, a guide plate is disposed outside of a polarization plate in front of a liquid crystal cell or is interposed between the liquid crystal cell and another polarization plate on the back side thereof.

A liquid crystal display panel of a display is illuminated by a surface light source device. The surface light source device comprises a primary light source consisting of, for example, a point-like light source and a light guide plate which is supplied with light to be introduced through an incidence face and to be emitted through an emission face. A back face is provided with repeatedly configurated slopes having inclinations such that a backward inner propagation light is converted into an inner reflection light directed to the emission face in order to urge the backward inner propagation light to be emitted preferentially through the emission face. A forward inner propagation light travelling toward a distal end face from an incidence face is rather restrained from being emitted. The backward inner propagation light, which is produced by a reflection at the distal end face, is inner-reflected at the repeatedly configurated slopes on the way of approaching the incidence face, resulting in an effective producing of light which is directed to the emission face.

Light guide plate, surface light source device and display

A light guide plate has a back face provided with a first light diffusion pattern which tends to get denser according to an increasing distance from a primary light source. The light guide plate has an emission face provided with a second light diffusion pattern covering rate of is the largest at an approximately center portion (particular partial region) of the emission face. The first and second light diffusion patterns consist of a great number of fine light diffusion elements, respectively. Each fine light diffusion element of the second light diffusion pattern has a smaller size as compared with that of the first light diffusion pattern. The emission face of the light guide plate has an effective emission area to provide an emission light which is supplied to an LCD panel or other objects to be illuminated, via a light control member such as prism sheet. The approximately center portion and/or other one or more particular partial regions in the emission face show an intentionally heightened brightness. This enables an image display unit to have an approximately center portion and/or other one or more particular partial regions which display a brightness-emphasized image. Such an emphasis display technique is suitably applied to devices such as digital still cameras or digital video cameras which employ image-screen-center-portion focusing.&square;

Surface light source device, display and light guide plate

A light regulator and a surface light source device employing the light regulator. For liquid-crystal display applications, the surface light source device can effectively prevent degradation in the quality of the emitted light and can reliably provide the required directivity correction. The light regulator is formed by laminatedly arranging a light scattering surface between first and second sheet-like members. The two sheet-like members mutually differ in shape, material and refractive index. Scattering means arranged between the first and second sheet-like members prevents Newton's rings due to spaces between the two sheet-like members from occurring. A light diffusion sheet may be disposed between the first and second sheet-like members.

Growing community of inventors

Hatogaya, Japan

Kazumasa Ohsumi