Illumination – Revolving
Utility Patent
1998-12-03
2001-01-02
Cariaso, Alan (Department: 2875)
Illumination
Revolving
C362S330000, C362S561000, C349S063000
Utility Patent
active
06168281
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a transparent and spread illuminating apparatus which is integrated with a display unit used as a front-face illuminating means of a variety of reflection type display units, and more particularly to a transparent and spread illuminating apparatus used as a front-surface illuminating means for a reflection type liquid-crystal display unit.
2. Background of Related Art
A liquid-crystal display unit operable with a low power consumption has been demanded increasingly for display units mainly applied to computers since it is thin in configuration, light in weight and so on. Because liquid crystal which is a structural element of the liquid-crystal display unit emits no light by itself, an illuminating means for illuminating an image is required, which is different from a light emission type device such as a CRT. In particular, in the circumstances where a demand of a fine and colored image in high level is increased recently, a structure in which a liquid-crystal display unit is backed with a high luminance spread light source is usually used. However, since in order to illuminate the spread light source, an excessive electric power is required, there occurs such a problem that the feature of liquid crystal having a low electric power consumption is lessened.
In particular, a portable liquid-crystal device frequently used with the advantages of the liquid-crystal display unit thin in configuration and light in weight has a drawback that the consumption of an internal electric power becomes increased due to the illumination of the spread light source which is provided in the liquid-crystal display unit to remarkably shorten a period of illuminating time for using it as the portable device.
In order to solve the above problem, there has been developed a reflection type liquid-crystal device that may operate by employing ambient light as an illuminating means even if no spread light source is provided.
An example of the most basic structure of the reflection type liquid-crystal device is shown in
FIG. 10. A
reflection type liquid-crystal display device
51
is designed in such a manner that transparent electrodes
53
a
and
53
b
are formed on opposite surfaces of a pair of glass substrates
52
a
and
52
b
, respectively, the transparent electrode
53
b
on a back surface B side (a lower side in
FIG. 10
) is patterned, and switching elements
54
are connected to the patterned transparent electrode
53
b
, respectively, to display a desired image.
Moreover, a space between the transparent electrodes
53
a
and
53
b
is filled with a liquid-crystal material
55
. Also, a color filter
56
is disposed between the glass electrode
52
a
and the transparent electrode
53
a
which are on a side of an observation face F (an upper side in FIG.
10
). Polarizing plates
57
a
and
57
b
are disposed on the other surfaces of the glass substrate
52
a
and
52
b
where no transparent electrodes
53
a
and
53
b
are provided, respectively. In addition, there is provided a high-efficiency reflector
58
that covers the polarizing plate
57
b
on the back surface B side.
In the reflection type liquid-crystal device
51
thus structured, by reflecting incident light to the reflector
58
disposed on the back surface B from the surroundings, a screen is brightly irradiated to enable to observe an image.
In the reflection type liquid-crystal device
51
thus structured, since the incident light to the reflector
58
disposed on the back surface B from the surroundings is reflected so as to be irradiated onto a screen, its display quality depends on the ambient brightness.
In particular, under the circumstance where the image is required to be high in quality, in the reflection type liquid-crystal devices of color display which are increased in demand, the reflection rate is generally lower than that of monochrome liquid crystal because of the provision of a color filter and the like, and therefore in the case where a brightness is not ensured in the surroundings and the luminance of the screen is insufficient, it becomes necessary to provide an auxiliary illumination for increasing the amount of an incident light to the reflector
58
in order to observe the image. The auxiliary illumination may be a table lamp or the like. However, it is troublesome always carry the illuminating apparatus to use it as the auxiliary illumination and the color-display reflection type liquid-crystal device cannot be used in the environment where the amount of the incident light to the reflector
58
is insufficient, resulting in a great loss of the advantages of the portable device.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems, and therefore an object of the present invention is to provide a transparent and spread illuminating apparatus which is structured to be integrated with a reflection type liquid-crystal display device, thereby being capable of being used without requiring the auxiliary lighting and also without being influenced by the brightness of surroundings, and further being easy to carry it low in electric power consumption.
In order to solve the above problems, according to a first aspect of the present invention, there is provided an illuminating apparatus disposed closely to a member to be illuminated so as to cover a front surface of the member to be illuminated, characterized in that a light source lamp is disposed closely along at least one side end surface of a transparent substrate made of a translucent material, a large number of grooves which are substantially triangular in section are formed in parallel with an axial direction of said light source lamp to provide a light reflection pattern consisting of said grooves and flat portions, and said grooves are defined in such a manner that the combined amount of light being caused by the reflection at said grooves and depending on a distance from said light source lamp become identical everywhere on the back surface of said transparent substrate.
According to a second aspect of the present invention, there is provided an illuminating apparatus characterized in that said member to be illuminated comprises a reflection type liquid-crystal display device.
According to a third aspect of the present invention, there is provided an illuminating apparatus characterized in that said light reflection pattern is formed in such a manner that the ratio in width of said grooves and said flat portions becomes larger as said grooves are separated from the light source lamp in the case where the depth of the respective grooves is constant, and the depth of the grooves becomes deeper as the grooves are apart from the light source lamp in the case where the widths of the flat portions are constant, or the light reflection pattern is formed by the combining the above with each other.
According to a fourth aspect of the present invention, there is provided an illuminating apparatus characterized in that said light reflection pattern is formed in such a manner that the width of said grooves is 1.5 times as large as the width of said flat portions, or less.
According to a fifth aspect of the present invention, there is provided an illuminating apparatus characterized in that said grooves are formed in such a manner that an angle of inclination of one inclined face of the grooves which is closer to the light source lamp is set at 35° to 55° and an angle of inclination of the other inclined face of the grooves which is opposite to said one inclined face is set at 60° to 90°.
According to a sixth aspect of the present invention, there is provided an illuminating apparatus characterized in that said grooves are formed in such a manner that the angles of valley portions which correspond to the angles of the apex of the grooves which are triangular in section are constant.
According to a seventh aspect of the present invention, there is provided an illuminating apparatus characterized in that the intensity of light emission from said light sou
Cariaso Alan
Minebea Co. Ltd.
Oliff & Berridg,e PLC
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