JP2000292786A - Linear light source and liquid crystal display device using the linear light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a linear light source which lights up an object surface so that its luminance distribution is symmetrical with respect to the length of the linear light source. SOLUTION: This device is equipped with a transparent quadratic prism 11 which is equipped with a light source 13 on at least one of the lengthwise end surfaces and has on the rear side surface many reflecting grooves 11a reflecting the light from the light source to the front side facing the rear surface, a reflecting sheet 14 which covers both the rear surface and both the surfaces adjacent to the rear surface, and a prism sheet 12 which is installed on the front surface and directs the light reflected by the reflecting grooves 11a perpendicularly to the front surface to emit the light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear light source used for a liquid crystal display device or an image reading device such as a facsimile or an electronic copying machine. The present invention relates to a liquid crystal display device using the configured lighting device.

[0002]

2. Description of the Related Art A linear light source is used as an illumination light source for a liquid crystal display device or an illumination device used for an image reading device such as a facsimile or an electronic copying machine. Conventionally, fluorescent tubes and LED (light emitting diode) arrays are known as the linear light source.

[0003] A fluorescent tube is most often used, but since this fluorescent tube is driven at a high voltage, an auxiliary circuit for generating the driving voltage is required.

[0004] In recent years, there has been known an LED array employing an LED array in response to a demand for small size and light weight. However, this LE
Since the D array requires a large number of LED chips, it has a problem of high power consumption and high cost.

In order to solve the drawbacks of the linear light source using the LED array, the number of LED chips is reduced,
An ED chip having a structure for converting a point light source to a linear light source has been proposed.

FIG. 12 is an explanatory view of a structural example in which a linear light source is formed by using one LED chip. In the figure, (a) shows a top view of the linear light source, and (b) shows a luminance distribution parallel to the longitudinal direction of the linear light source. In FIG. 1A, reference numeral 11 denotes a transparent quadrangular prism having a rectangular cross section, in which an LED chip 13 is provided at an edge in a longitudinal direction, and a reflection groove 11a is formed on one side surface. This groove is formed at right angles to the longitudinal direction of the transparent square pillar.

Light from the LED chip 13 installed at one end in the longitudinal direction of the transparent quadrangular prism 11 travels in the right-hand direction in the figure while being reflected inside the quadrangular prism, but is formed on the rear side surface of the quadrangular prism. The path is changed by being reflected by a number of reflection grooves 11a, and is emitted from the front side surface in the direction of the illumination target surface as indicated by the arrow.

This emitted light L is applied to a square pillar 11
Are shifted to the right in the longitudinal direction, and the luminance distribution on the illuminated surface is asymmetrical on the left and right as shown in FIG. Therefore, when such a linear light source is used for illumination of a liquid crystal display device, for example, there is a problem that the brightness distribution of the screen becomes uneven.

[0009]

In order to eliminate the above-mentioned uneven brightness, Japanese Patent Laid-Open Publication No. Hei 10-133,026 discloses a method in which LEDs are provided at both ends in the longitudinal direction of a transparent rectangular column.
Although the chips are installed, the number of LED chips increases, so that power consumption increases.

A first object of the present invention is to provide a linear light source which solves the above-mentioned problem of the prior art and has a luminance distribution on an illuminated surface which is symmetrical in the longitudinal direction of the linear light source in the left and right directions. It is in.

A second object of the present invention is to provide a liquid crystal display device equipped with a lighting device constituted by the linear light source.

[0012]

In order to achieve the first object, according to the present invention, a light reflecting groove is formed on a rear surface or a rear peripheral surface, and an LED is provided at an end in a longitudinal direction thereof. Using a transparent square pole or a cylinder provided with a reflective sheet that covers both sides adjacent to the rear side or the rear side adjacent to the rear side peripheral side, and a front side or front side peripheral side provided with a reflective sheet,
A linear light source is provided on the front side surface or the front side peripheral surface by installing a prism sheet that changes a traveling path (a traveling direction) of light from the light reflection groove formed on the rear side surface or the rear side peripheral surface.

In addition, instead of the prism sheet, on the front side surface or the front side peripheral surface of the transparent quadrangular prism or cylinder,
The light reflecting groove (first
A prism groove (second groove) for changing the path of light from the groove) was formed to obtain a linear light source.

In order to achieve the second object of the present invention, the present invention provides a liquid crystal display device in which the linear light source is arranged on at least one side of a display surface when the liquid crystal panel is of a reflective type. Alternatively, a light guide plate made of a transparent plate was laminated on the display surface of the liquid crystal panel, and the linear light source was installed on at least one edge of the light guide plate to obtain a surface light source.

When the liquid crystal panel is of a transmissive type, a light guide plate made of a transparent plate is laminated on the back surface opposite to the display surface of the liquid crystal panel, and the linear light source is installed on at least one edge of the light guide plate. Then, a surface light source was obtained.

Hereinafter, a typical configuration of the present invention will be described as follows. That is, as a configuration of the linear light source, (1) a light source is provided on at least one of the longitudinal end surfaces, and a large number of reflection grooves are formed on the rear surface to reflect light from the light source toward the front surface facing the rear surface. A transparent quadrangular prism, a reflective sheet covering the rear side surface and both side surfaces adjacent to the rear side surface, and a light installed on the front side surface and emitted in a direction perpendicular to the front side surface and reflected by the reflection groove. And a prism sheet.

(2) A light source is provided on at least one of the end faces in the longitudinal direction, and a plurality of first grooves are formed on the rear side surface for reflecting light from the light source toward the front side surface facing the rear side surface.
And a transparent quadrangular prism formed on the front side surface with a second groove for emitting light mainly reflected by the first groove in a direction perpendicular to the front side surface and emitting the light, and the rear side surface and both side surfaces adjacent to the rear side surface. And a reflection sheet for covering the surface.

(3) A light source is provided on at least one of the end faces in the longitudinal direction, and a large number of grooves are formed on the rear peripheral face so as to reflect light from the end face toward the front peripheral face facing the rear peripheral face. A transparent column, a reflective sheet covering the rear peripheral surface and both adjacent peripheral surfaces adjacent to the rear peripheral surface, and opening and opening a front peripheral surface facing the rear peripheral surface; and the front peripheral surface. And a prism sheet installed at

(4) A light source is provided on at least one of the longitudinal end surfaces, a plurality of first grooves for refracting light from the end surface side are formed on the rear peripheral surface, and a front side facing the rear peripheral surface. A transparent cylinder having a large number of second grooves formed on a peripheral surface thereof, the light mainly reflected by the first groove being directed in a direction perpendicular to the front peripheral surface and emitting the light; and a rear peripheral surface and a rear peripheral surface. A reflecting sheet covering the adjacent peripheral surfaces on both sides continuous and opening the front peripheral surface facing the rear peripheral surface.

According to the linear light source having the above-described constitutions (1) to (4), the luminance distribution of the illuminating light symmetrical with respect to the center in the longitudinal direction of the transparent square pillar or the transparent cylinder can be obtained with one LED chip. Can be Further, low power consumption can be achieved.

According to another aspect of the present invention, there is provided a liquid crystal display comprising: (5) a liquid crystal panel, an illuminating device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel. A display device, wherein the illumination device includes a light source on at least one of the longitudinal end surfaces, and a plurality of reflection grooves for reflecting light from the light source in a front surface direction facing the rear surface are formed on a rear surface. A transparent quadrangular prism, a reflective sheet covering the rear side surface and both side surfaces adjacent to the rear side surface, and light emitted from the reflective groove disposed on the front side surface and directed in a direction perpendicular to the front side surface and emitted. And a linear light source having a prism sheet. The linear light source was installed on one side of the liquid crystal panel on the display surface side, and the display surface of the display panel was illuminated with illumination light.

(6) A liquid crystal display device comprising a liquid crystal panel, an illuminating device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel, wherein the illuminating device is A light source on at least one of the longitudinal end surfaces, a plurality of first grooves for reflecting light from the light source in a front surface direction facing the rear surface are formed on the rear surface, and the first groove is mainly formed on the front surface. A line having a transparent quadrangular prism formed with a second groove for emitting the light reflected by one groove in a direction perpendicular to the front surface and emitting the light, and a reflection sheet covering the rear surface and both side surfaces adjacent to the rear surface. The linear light source is connected to the display surface side of the liquid crystal panel.
It was arranged on the side to illuminate the display surface of the display panel with illumination light.

(7) A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel, wherein the lighting device is A light source provided on at least one of the longitudinal end faces, a transparent cylinder having a plurality of grooves formed on a rear peripheral face in a direction of a front peripheral face facing the rear peripheral face with light from the end face side, A reflective sheet that covers the rear peripheral surface and an adjacent peripheral surface that is continuous with the rear peripheral surface, and is provided with the front peripheral surface facing the rear peripheral surface being opened, and a prism sheet that is disposed on the front peripheral surface. And the linear light source is installed on one side on the display surface side of the liquid crystal panel to illuminate the display surface of the display panel with illumination light.

(8) A liquid crystal display device including a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the lighting device is A light source is provided on at least one of the longitudinal end surfaces, a large number of first grooves are formed on the rear peripheral surface to refract light from the end surface side, and the main peripheral surface is opposed to the rear peripheral surface. A transparent column formed with a number of second grooves for emitting light reflected by the first groove in a direction perpendicular to the front peripheral surface and forming a plurality of second grooves, the rear peripheral surface and an adjacent peripheral surface continuous to the rear peripheral surface; A light source having a reflection sheet covering the rear surface and opening the front peripheral surface facing the rear peripheral surface. The linear light source is installed on one side of the liquid crystal panel on the display surface side. To illuminate the display surface of the display panel with illumination light.

(9) A liquid crystal display device comprising a liquid crystal panel, an illuminating device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel, wherein the illuminating device is A light source provided on at least one of the longitudinal end faces, a transparent square pillar having a plurality of reflection grooves formed on a rear side face to reflect light from the light source in a front side direction facing the rear side face, and the rear side face and A reflective sheet that covers both side surfaces adjacent to the rear side surface, and a linear light source having a prism sheet installed on the front side surface and directing light reflected by the reflection groove in a direction perpendicular to the front side surface and emitting the light. A light guide plate made of a transparent plate laminated on a display surface of the liquid crystal panel, and the front surface of the linear light source is installed along one side of the light guide plate so as to be close to each other. Guides the light emitted from the light source While propagating in the plate were composed as to illuminate the display surface of the liquid crystal panel.

(10) A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the lighting device is A light source on at least one of the longitudinal end surfaces, a plurality of first grooves for reflecting light from the light source in a front surface direction facing the rear surface are formed on the rear surface, and the first groove is mainly formed on the front surface. A transparent quadrangular prism having a second groove formed for directing light reflected by one groove in a direction perpendicular to the front side surface and emitting the light; a reflection sheet covering the rear side surface and both side surfaces adjacent to the rear side surface; It has a light guide plate made of a transparent plate laminated on the display surface of the panel, and is disposed along one side of the light guide plate so that the front side of the lighting device is close to the light guide plate, and emits light from the linear light source. Propagating light to the light guide plate And as it configured to illuminate the display surface of the liquid crystal panel.

(11) A liquid crystal display device comprising a liquid crystal panel, an illumination device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel, wherein the illumination device is A light source provided on at least one of the longitudinal end faces, a transparent cylinder having a plurality of grooves formed on a rear peripheral face in a direction of a front peripheral face facing the rear peripheral face with light from the end face side, A front side that covers the rear peripheral surface and the adjacent peripheral surface that is continuous with the rear peripheral surface, covers the rear peripheral surface and the adjacent peripheral surface that is continuous with the rear peripheral surface, and faces the rear peripheral surface. A reflective sheet provided with an open peripheral surface, a prism sheet provided on the front peripheral surface, and a light guide plate comprising a transparent plate laminated on a display surface of the liquid crystal panel,
The linear light source is disposed along one side of the light guide plate such that the front side surface is close to the light source, and the display surface of the liquid crystal panel is illuminated while light emitted from the linear light source propagates to the light guide plate. It was configured as follows.

(12) A liquid crystal display device comprising a liquid crystal panel, an illuminating device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the illuminating device is A light source is provided on at least one of the longitudinal end surfaces, a large number of first grooves are formed on the rear peripheral surface to refract light from the end surface side, and the main peripheral surface is opposed to the rear peripheral surface. A transparent column formed with a number of second grooves for emitting light reflected by the first groove in a direction perpendicular to the front peripheral surface and forming a plurality of second grooves, the rear peripheral surface and an adjacent peripheral surface continuous to the rear peripheral surface; A reflective sheet that covers the surface and is installed with the front peripheral surface facing the rear peripheral surface opened, and a light guide plate made of a transparent plate laminated on the display surface of the liquid crystal panel. Place the front side of the linear light source close to and along one side Ri, and as configured to illuminate the display surface of the liquid crystal panel with light emitted from the linear light source while propagating in the light guide plate.

(13) A liquid crystal display device comprising a liquid crystal panel, an illuminating device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the illuminating device is A light source provided on at least one of the longitudinal end faces, a transparent square pillar having a plurality of reflection grooves formed on a rear side face to reflect light from the light source in a front side direction facing the rear side face, and the rear side face and A reflecting sheet that covers both side surfaces adjacent to the rear side surface, a prism sheet that is installed on the front side surface and directs light reflected by the reflection groove in a direction perpendicular to the front side surface and emits light, and a rear surface of the liquid crystal panel. A light guide plate made of a laminated transparent plate, and a reflector provided on a side of the light guide plate opposite to the liquid crystal panel,
The front side of the linear light source is installed close to one side of the light guide plate, and the light emitted from the lighting device is emitted to the liquid crystal panel side while being transmitted to the light guide plate,
The liquid crystal panel was configured to be illuminated from the back.

(14) A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the lighting device is A light source on at least one of the longitudinal end surfaces, a plurality of first grooves for reflecting light from the light source in a front surface direction facing the rear surface are formed on the rear surface, and the first groove is mainly formed on the front surface. A transparent quadrangular prism having a second groove formed for directing light reflected by one groove in a direction perpendicular to the front side surface and emitting the light; a reflection sheet covering the rear side surface and both side surfaces adjacent to the rear side surface; A light guide plate made of a transparent plate laminated on the back surface of the panel; and a reflector provided on a side of the light guide plate opposite to the liquid crystal panel, wherein the linear light source extends along one side of the light guide plate. Place the front side close to Ri, while propagating light emitted from the linear light source to the light guide plate is emitted to the liquid crystal panel side, and as configured to illuminate the liquid crystal panel from the back.

(15) A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the lighting device is A light source provided on at least one of the longitudinal end faces, a transparent cylinder having a plurality of grooves formed on a rear peripheral face in a direction of a front peripheral face facing the rear peripheral face with light from the end face side, A reflective sheet that covers the rear peripheral surface and an adjacent peripheral surface that is continuous with the rear peripheral surface, and is provided with the front peripheral surface facing the rear peripheral surface being opened, and a prism sheet that is disposed on the front peripheral surface. And a light guide plate made of a transparent plate laminated on the back surface of the liquid crystal panel, and a reflection plate provided on a side of the light guide plate opposite to the liquid crystal panel, and along one side of the light guide plate. Do not install the linear light source close to the front peripheral surface. , While propagating light emitted from the linear light source to the light guide plate is emitted to the liquid crystal panel side,
The liquid crystal panel was configured to be illuminated from the back.

(16) A liquid crystal display device comprising a liquid crystal panel, an illuminating device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel, wherein the illuminating device is A light source is provided on at least one of the longitudinal end surfaces, a large number of first grooves are formed on the rear peripheral surface to refract light from the end surface side, and the main peripheral surface is opposed to the rear peripheral surface. A transparent column formed with a number of second grooves for emitting light reflected by the first groove in a direction perpendicular to the front peripheral surface and forming a plurality of second grooves, the rear peripheral surface and an adjacent peripheral surface continuous to the rear peripheral surface; A reflective sheet that covers the surface and is installed with the front peripheral surface facing the rear peripheral surface opened, a light guide plate made of a transparent plate laminated on the back surface of the liquid crystal panel, and the liquid crystal panel of the light guide plate. Has a reflection plate on the opposite side, and is provided on one side of the light guide plate. Be installed in close proximity to the front peripheral surface of the linear light source I, to emit the light emitted from the linear light sources to the liquid crystal panel side while propagating in the light guide plate,
The liquid crystal panel was configured to be illuminated from the back.

According to the liquid crystal display device having the above constitutions (5) to (16), the power consumption of the whole liquid crystal display device can be reduced, and the battery life of a portable personal computer or the like can be remarkably improved. Various information processing terminals and other electronic devices with a long operating time can be obtained.

It should be noted that the present invention is not limited to the above configuration, and does not depart from the technical idea of the present invention.
It goes without saying that various changes are possible.

[0035]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating the configuration of a first embodiment of a linear light source according to the present invention. FIGS. 2A and 2B are schematic diagrams for explaining the configuration of the linear light source according to the first embodiment of the present invention in more detail. FIG. 2A is a top view, and FIG. (C) shows the edge viewed from the arrow B direction of (a).

In this embodiment, a transparent quadrangular prism 11 formed of an acrylic resin is used, and a light reflecting groove 11a
Is formed. Then, an LED chip 13 was installed at one longitudinal edge of the square pillar 11, and a prism sheet 12 for changing the path of light reflected from the light reflecting groove 11a was installed on the front side surface. Fixing of LED chip 13 and square pillar 11, prism sheet 12 to square pillar 11
It is preferable to use an epoxy-based adhesive for the attachment.

A reflecting sheet 14 is provided so as to cover the rear side surface (rear surface) of the quadrangular prism 11 on which the light reflecting groove 11a is formed, and both side surfaces (upper and lower surfaces in FIG. 1) adjacent to the rear side surface.

Light emitted from the LED 13 is incident on the quadrangular prism 11 and propagates rightward in the figure. On the way, the light is reflected by the light reflection groove 11a formed on the rear side surface and exits from the front side surface facing the rear side surface. As described with reference to FIG. 12, the light emitted from the quadrangular prism 11 is
In the right direction in the longitudinal direction.

The prism sheet 12 provided on the front side
Refracts the light emitted from the square pole and changes the path in the direction perpendicular to the longitudinal direction of the square pillar 11. That is, the light L refracted by the prism sheet 12 is incident on the illuminated surface at right angles.

According to this embodiment, a linear light source in which the luminance distribution on the surface to be illuminated is symmetrical in the left and right directions in the longitudinal direction of the linear light source can be obtained at low cost.

FIGS. 3A and 3B are schematic views illustrating the configuration of a linear light source according to a second embodiment of the present invention. FIG.
(B) shows the edge seen from the arrow A direction of (a).

In this embodiment, a light reflecting groove 11a is formed on the rear surface of a transparent square pillar 11 formed of an acrylic resin, and the light reflecting groove 11a is formed on a front surface facing the rear surface.
Groove 11b that changes the path of light reflected from the surface
Was formed. Then, an LED chip 13 was attached and fixed to one end in the longitudinal direction of the square pillar 11 using an epoxy resin.

The back surface (back surface) on which the light reflecting groove 11a of the square pole 11 is formed and the side surfaces (upper surface and lower surface in FIG. 1) adjacent to the rear surface are covered with the same reflection as in the first embodiment. A seat 14 is provided.

The light emitted from the LED 13 is incident on the quadrangular prism 11 and propagates rightward in the figure. On the way, the light is reflected by the light reflecting groove 11a formed on the rear surface, and is emitted from the prism groove 11b formed on the front surface facing the rear surface. As described with reference to FIG. 12, the light emitted from the quadrangular prism 11 is to be shifted to the right side in the longitudinal direction of the quadrangular prism 11 with respect to the front side surface.
The path L is refracted by 1b, and the path is changed in the direction perpendicular to the longitudinal direction of the square pillar 11, and the light L refracted and emitted enters the surface to be illuminated at right angles.

According to this embodiment, a linear light source in which the luminance distribution on the illuminated surface is symmetrical in the longitudinal direction of the linear light source on the left and right sides can be obtained at low cost.

FIGS. 4A and 4B are schematic views illustrating the configuration of a third embodiment of the linear light source according to the present invention. FIG.
(B) shows the edge seen from the arrow A direction of (a).

In this embodiment, the LED chip 13 adhered to the edge of the square pillar 11 in the embodiment described with reference to FIG. 1 is embedded in the square pillar 11. With this configuration, the injection efficiency of the LED can be improved.

It should be noted that the structure of this embodiment is the same as that of the second embodiment,
It goes without saying that the same can be applied to the third embodiment.

FIGS. 5A and 5B are schematic views for explaining the structure of a linear light source according to a fourth embodiment of the present invention. FIG.
(B) shows a cross section viewed from the AA cross section of (a).

In this embodiment, a light reflecting groove 110a is formed on the rear peripheral surface of a transparent cylinder 110 formed of an acrylic resin. Then, a prism sheet 120 for changing the path of the light reflected from the light reflecting groove 110a was provided on the front peripheral surface facing the rear peripheral surface. This prism sheet 120
Has a curve along the curved surface of the column 110 and is bonded to the column 110 with an epoxy resin.

Then, an LED chip 130 was attached and fixed to one end of the column 110 in the longitudinal direction using an epoxy resin.

The rear peripheral surface (back peripheral surface) of the cylinder 110 on which the light reflecting groove 110a is formed, and both peripheral surfaces (upper and lower peripheral surfaces in FIG. 5) continuous with the rear peripheral surface. A reflection sheet 140 is provided so as to cover.

The light emitted from the LED 130 is
And propagates rightward in the figure. On the way, the light is reflected by the light reflecting groove 110a formed on the rear peripheral surface, and is emitted to the prism sheet 120 from the front peripheral surface facing the rear peripheral surface.

By passing through the prism sheet 120, the light emitted from the cylinder 110 is refracted and the path is changed in a direction perpendicular to the longitudinal direction of the cylinder 110, and the refracted and emitted light L is perpendicular to the surface to be illuminated. Incident on.

According to this embodiment, a linear light source in which the luminance distribution on the illuminated surface is symmetrical in the left and right directions in the longitudinal direction of the linear light source can be obtained at low cost.

FIG. 6 is a cross-sectional view corresponding to the AA cross section of FIG. 5 for explaining another embodiment of the linear light source according to the present invention.
FIG. 7A shows a plate-like prism sheet in place of the prism sheet 120 in FIG.

(B) does not use a prism sheet,
A prism groove 110b is formed on the front peripheral surface of the cylinder 110. (C) shows a prism 110 having a prism groove 110c formed on the entire peripheral surface thereof.

According to this embodiment, a linear light source in which the luminance distribution on the surface to be illuminated is symmetrical in the left and right directions in the longitudinal direction of the linear light source can be obtained at low cost.

FIG. 7 is a schematic explanatory view of a measurement system for measuring the luminance distribution of the linear light source on the surface to be irradiated, and shows a position (0 °) perpendicular to the front side surface or the front side peripheral surface of the linear light source 1. )
80 ° left to right (left: + 80 °, right: −80
The luminance of the light emitted from the linear light source 1 is measured by positioning the luminance meter 20 in the range of (°).

FIG. 8 is an explanatory view of the luminance distribution of the linear light source measured by the measuring system of FIG. 7, where a is the luminance distribution of the linear light source according to the present invention, and b is the conventional linear light source described in FIG. 5 shows the luminance distribution of. As can be seen from the measurement results, the luminance distribution of the linear light source according to the present invention is symmetric with respect to the center.

Next, a liquid crystal display device using a linear light source according to the present invention will be described.

FIG. 9 is a schematic view for explaining a first embodiment of the liquid crystal display device according to the present invention. Reference numeral 15 denotes a reflection type liquid crystal panel, and FIG.
One of the linear light sources described with reference to FIG. 6 is installed.

The light from the linear light source 1 irradiates the display surface of the liquid crystal panel, and the reflected light visualizes the image formed on the liquid crystal panel. Such an illumination system is particularly suitable for a liquid crystal display device having a small screen, such as a personal digital assistant (PDA).

FIG. 10 shows a second embodiment of the liquid crystal display device according to the present invention.
FIG. 15B is a schematic view for explaining the embodiment, wherein 15B is a reflection type liquid crystal panel, and a light guide plate 16 made of a transparent plate is laminated on the display surface of the liquid crystal panel. 6 to any one of the linear light sources described with reference to FIG.

The light from the linear light source 1 illuminates the liquid crystal panel 15B while propagating through the light guide plate 16A, and the reflected light visualizes the image formed on the liquid crystal panel. Such an illumination system is also particularly suitable for a liquid crystal display device having a small screen, such as a personal digital assistant (PDA).

FIG. 11 shows a third embodiment of the liquid crystal display device according to the present invention.
FIG. 15 is a schematic view for explaining the embodiment, in which 15C is a transmissive liquid crystal panel, and a light guide plate 16B made of a transparent plate is laminated on the back surface of the liquid crystal panel. One of the linear light sources described with reference to FIG. 6 is installed. A reflection plate 17 is provided on the rear surface of the light guide plate 16B to effectively use light propagating through the light guide plate.

The light from the linear light source 1 illuminates the liquid crystal panel 15B from the back while propagating through the light guide plate 16B, and the transmitted light visualizes the image formed on the liquid crystal panel. Such a lighting system is suitable for a liquid crystal display device such as a notebook computer or a desktop monitor having a relatively large screen.

In the various liquid crystal display devices described above,
The light emitted from the linear light source has a luminance distribution as shown in FIG. In order to make the luminance of the screen uniform over the entire display area, dot printing or surface processing for controlling the amount of transmission or reflection may be performed on the surface of the liquid crystal panel or the surface of the light guide plate.

The linear light source according to the present invention is applicable not only to the above-mentioned liquid crystal display device but also to a light source of a facsimile, an electronic copying machine, and other image reading devices.

[0071]

As described above, according to the present invention,
Provides a linear light source that has a simple configuration, has no uneven brightness distribution, and has reduced power consumption.Provides information devices such as liquid crystal display devices that achieve overall power savings by adopting this linear light source. can do.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the configuration of a linear light source according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining the configuration of the first embodiment of the linear light source according to the present invention in further detail.

FIG. 3 is a schematic diagram illustrating a configuration of a linear light source according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating the configuration of a third embodiment of the linear light source according to the present invention.

FIG. 5 is a schematic diagram illustrating a configuration of a linear light source according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view corresponding to the AA cross section of FIG. 5 for explaining another embodiment of the linear light source according to the present invention.

FIG. 7 is a schematic explanatory diagram of a measurement system for measuring a luminance distribution of a linear light source on an irradiation surface side.

FIG. 8 is an explanatory diagram of a luminance distribution of a linear light source measured by the measurement system of FIG. 7;

FIG. 9 is a schematic diagram illustrating a first embodiment of a liquid crystal display device according to the present invention.

FIG. 10 is a schematic diagram illustrating a second embodiment of the liquid crystal display device according to the present invention.

FIG. 11 is a schematic diagram illustrating a third embodiment of the liquid crystal display device according to the present invention.

FIG. 12 is an explanatory diagram of a structural example in which a linear light source is configured using one LED chip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Linear light source 11 Square prism 11a Light reflection groove 11b Prism groove 12 Prism sheet 13 LED chip 14 Reflection sheet.

Claims (8)

[Claims] 1. A transparent quadratic prism having a light source on at least one of its longitudinal end faces, and having a plurality of reflection grooves formed on a rear surface thereof for reflecting light from the light source toward a front surface facing the rear surface. A reflecting sheet that covers the rear side surface and both side surfaces adjacent to the rear side surface, and a prism sheet that is installed on the front side surface and directs light reflected by the reflection groove in a direction perpendicular to the front side surface and emits the light. A linear light source characterized in that: 2. A method according to claim 1, wherein a light source is provided on at least one of the longitudinal end surfaces, and a plurality of first grooves for reflecting light from the light source in a front surface direction facing the rear surface are formed on the rear surface, and the front surface is formed. A transparent quadratic prism formed with a second groove that mainly directs light reflected by the first groove in a direction perpendicular to the front surface and emits the light; and a reflection sheet that covers the rear surface and both side surfaces adjacent to the rear surface. A linear light source characterized by comprising: 3. A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a drive circuit for displaying an image on the liquid crystal panel, wherein the lighting device comprises: A transparent quadrangular prism having a light source on at least one of the longitudinal end surfaces, and having a plurality of reflection grooves formed on a rear surface thereof for reflecting light from the light source in a front surface direction facing the rear surface, and the rear surface and the rear thereof. A reflection sheet covering both side surfaces adjacent to the side surface, and a linear light source having a prism sheet installed on the front side surface and directing the light reflected by the reflection groove in a direction perpendicular to the front side surface and emitting the light,
A liquid crystal display device, wherein the linear light source is installed on one side of the display surface of the liquid crystal panel so as to irradiate the display surface of the display panel with illumination light. 4. A liquid crystal display device comprising: a liquid crystal panel; an illuminating device for illuminating a display surface of the liquid crystal panel; and a driving circuit for displaying an image on the liquid crystal panel. A light source is provided on at least one of the longitudinal end surfaces, a plurality of first grooves are formed on a rear surface of the light source so as to reflect light from the light source toward a front surface facing the rear surface, and the first groove is mainly formed on the front surface. A linear prism having a transparent rectangular prism having a second groove formed therein for directing the light reflected by the groove in a direction perpendicular to the front surface and emitting the light, and a reflecting sheet covering the rear surface and both side surfaces adjacent to the rear surface; A liquid crystal display device comprising a light source, wherein the linear light source is installed on one side of the display surface of the liquid crystal panel to illuminate the display surface of the display panel with illumination light. 5. A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the lighting device comprises: A transparent quadrangular prism having a light source on at least one of the longitudinal end surfaces, and having a plurality of reflection grooves formed on a rear surface thereof for reflecting light from the light source in a front surface direction facing the rear surface, and the rear surface and the rear thereof. A linear sheet light source having a reflecting sheet covering both side surfaces adjacent to the side surface, and a prism sheet installed on the front side surface and directing light reflected by the reflection groove in a direction perpendicular to the front side surface and emitting the light; A light guide plate made of a transparent plate laminated on a display surface of the liquid crystal panel, wherein the linear light source is disposed along one side of the light guide plate such that a front surface of the linear light source is close to the light guide plate; The light emitted from the light guide plate The liquid crystal display device, characterized in that the as configured to illuminate the display surface of the liquid crystal panel while propagation. 6. A liquid crystal display device comprising: a liquid crystal panel; an illuminating device for illuminating a display surface of the liquid crystal panel; and a driving circuit for displaying an image on the liquid crystal panel. A light source is provided on at least one of the longitudinal end surfaces, a plurality of first grooves are formed on a rear surface of the light source so as to reflect light from the light source toward a front surface facing the rear surface, and the first groove is mainly formed on the front surface. A transparent quadrangular prism having a second groove formed therein for directing light reflected by the groove in a direction perpendicular to the front side surface and emitting the light; a reflection sheet covering the rear side surface and both side surfaces adjacent to the rear side surface; A light guide plate made of a transparent plate laminated on the display surface of (1), and the light guide plate is disposed along one side of the light guide plate so that a front side surface of the lighting device is close to the light guide plate, and light emitted from the linear light source is provided. While propagating to the light guide plate The liquid crystal display device, characterized in that the as configured to illuminate the display surface of the LCD panel. 7. A liquid crystal display device comprising a liquid crystal panel, a lighting device for illuminating a display surface of the liquid crystal panel, and a driving circuit for displaying an image on the liquid crystal panel, wherein the lighting device comprises: A transparent quadrangular prism having a light source on at least one of the longitudinal end surfaces, and having a plurality of reflection grooves formed on a rear surface thereof for reflecting light from the light source in a front surface direction facing the rear surface, and the rear surface and the rear thereof. A reflection sheet that covers both side surfaces adjacent to the side surface, a prism sheet that is installed on the front side surface and directs light reflected by the reflection groove in a direction perpendicular to the front side surface and emits the light, and stacked on the back surface of the liquid crystal panel A light guide plate made of a transparent plate body, and a reflection plate installed on a side of the light guide plate opposite to the liquid crystal panel, and a front surface of the linear light source is brought close to one side of the light guide plate. And set it up, before While light emitted from the illuminating device to propagate to the light guide plate is emitted to the liquid crystal panel side, a liquid crystal display device, characterized in that the as configured to illuminate the liquid crystal panel from the back. 8. A liquid crystal display device comprising: a liquid crystal panel; a lighting device for illuminating a display surface of the liquid crystal panel; and a driving circuit for displaying an image on the liquid crystal panel. A light source is provided on at least one of the longitudinal end surfaces, a plurality of first grooves are formed on a rear surface of the light source so as to reflect light from the light source toward a front surface facing the rear surface, and the first groove is mainly formed on the front surface. A transparent quadrangular prism having a second groove formed therein for directing light reflected by the groove in a direction perpendicular to the front side surface and emitting the light; a reflection sheet covering the rear side surface and both side surfaces adjacent to the rear side surface; A light guide plate made of a transparent plate laminated on the back surface of the light guide plate, and a reflection plate provided on a side of the light guide plate opposite to the liquid crystal panel, and the linear light source is arranged along one side of the light guide plate. Installed with the front side close to, While propagating light emitted from the serial linear light sources to the light guide plate is emitted to the liquid crystal panel side, a liquid crystal display device, characterized in that the as configured to illuminate the liquid crystal panel from the back.