Display device and planar light source device

Abstract

The present invention relates to a technique which can make a backlight used in a liquid crystal display device thin and light-weighted. The present invention provides a liquid crystal display device which includes a display panel and a backlight which is arranged behind the display panel, wherein the backlight includes a film-like light guide member, a film-like light semi-transmissive member which is adhered to a first surface of the light guide member which faces the display panel in an opposed manner, a film-like reflective member which is adhered to a back surface of the light guide member opposite to the first surface, and a spot light source which is arranged at a position of the light guide member at which light is incident on the light guide member from the first surface or the back surface, and a refractive index of the light semi-transmissive member is set smaller than a refractive index of the light guide member.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The disclosure of Japanese Patent Application No. 2005-352167 filed on Dec. 6, 2005 including the specification, drawings and abstract is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a display device and a planar light source device, and more particularly to a technique which is effectively applicable to a planar light source device which radiates light propagated through a light guide plate and a display device which uses the planar light source device. [0004] 2. Description of the Related Arts [0005] Conventionally, as a display of a mobile phone or a notebook-type PC (Personal Computer) or the like, a liquid crystal display device (a liquid crystal display unit) having a liquid crystal display panel is used. [0006] The liquid crystal display device is roughly classified into a transmissive-type liquid crystal display device which...

AI Technical Summary

Benefits of technology

[0057]FIG. 17 is a schematic view for explaining one of advantageous effects of the backlight of the embodiment 4;

[0058]FIG. 18 is a schematic view showing a constitutional example of a display device which uses a conventional general backlight for comparing with the backlight of the embodiment 4;

[0059]FIG. 19 is a schematic view showing the schematic constitution of a backlight of an embodiment 5 according to the present invention;

[0060]FIG. 20 is a cross-sectional view taken along a line G-G′ in FIG. 19;

[0061]FIG. 21 is a schematic view for explaining a mounting method of an incident-light adjusting member;

[0062]FIG. 22 is a schematic view for explaining the manner of operation of the backlight of the embodiment 5;

Problems solved by technology

Accordingly, there has been a drawback that loss of light is increased.

Further, in general, the light guide plate is often formed by injection molding and hence, there has been a drawback that it is difficult to form the light guide plate into a shape as designed from a viewpoint of forming accuracy.

However, no consideration has been taken by the patent document 2 with respect to an incident angle of light when the light is incident on the light guide body layer from the light source.

Accordingly, for example, the light which is incident on the light guide plate at a small incident angle which does not generate the total reflection becomes dominant thus giving rise to a drawback that light cannot be effectively radiated into the inside of a display region of the liquid crystal display panel.

Accordingly, for example, when the spot light source such as the LED is used, there has been a drawback that it is difficult to make the brightness distribution of the light which is radiated into the inside of the display region of the liquid crystal display panel.

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