JPH07248495A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device having a back light whose light utilizing efficiency is enhanced. CONSTITUTION:The back light source of a liquid crystal display element is constituted of an ultraviolet lamp 20a, a light transmission body 21, a dichroic mirror 20e and a fluorescent film 20d. The mirror 20e is inserted on the lamp 20a side and the film 20d is inserted on the transmission body 21 side between the lamp 20a and the transmission body 21. Besides, the mirror 20e having such wavelength selecting property that only an ultraviolet ray area is substantially transmitted is used. Thus, the utilizing efficiency of the illumination light is drastically improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device provided with a so-called backlight light source, and more particularly to a liquid crystal display device provided with a backlight light source having a structure in which illumination efficiency is remarkably improved.

[0002]

2. Description of the Related Art Liquid crystal display devices are known to be of a transmissive type or a reflective type, depending on the illumination system. In particular, the transmissive type is widely adopted for image display of a simple matrix type STN liquid crystal display device or an active matrix type TFT liquid crystal display device.

A transmissive liquid crystal display device is provided with a light source device (backlight light source) for emitting planar illumination light on the back surface of a liquid crystal display element, and illuminates an effective screen area of the liquid crystal display element with light having a uniform distribution. Then, the light transmitted through the liquid crystal display element is observed.

FIG. 13 is a developed perspective view for explaining a structural example of a liquid crystal display device, in which 1 is a liquid crystal display element, 2 is a backlight light source, 3 is a printed circuit board, 4 is a frame, and 6 and 7 are spacers. .

In the structural example of FIG. 1, the backlight source 2 is a cylindrical fluorescent discharge lamp (for example, a straight tube cold cathode fluorescent lamp) 20, a light guide plate 21 made of a transparent material adjacent to the fluorescent discharge lamp 20, and a light guide plate. It is mainly composed of a reflection plate 22 installed on the back surface of 21 and a diffusion plate 23 installed on the front surface of the light guide plate 21.

The printed circuit board 3 controls the fluorescent discharge lamp 20.
Electronic circuit parts such as C31 and a drive IC 32 for driving a liquid crystal display element are mounted, and a slit 10 for fixing the frame is formed.

The frame 4 has a rim 41 for fixing the periphery by exposing the effective screen area of the liquid crystal display device, and also has a fixing piece 9 for inserting and fixing it in a slit 10 formed in a printed circuit board.

The fluorescent discharge lamps 20 constituting the backlight light source 2 are installed close to each other along the side surface of the light guide plate 21,
It is connected to a power source through the socket 24, the power supply line 25, and the connector 28.

The emitted light of the fluorescent discharge lamp 20 propagates through the light guide plate 21, is reflected by the reflection plate 22, and is directed toward the diffusion plate 23.

The fluorescent discharge lamp 20 is covered with a shield cover 26 fixed with screws 27 so that unnecessary light does not reach the liquid crystal display element or the like.

FIG. 14 is a schematic cross-sectional view for explaining an example of the arrangement of each member constituting the liquid crystal display device, and the same reference numerals as those in FIG. 13 correspond to the same parts.

As shown in FIG. 1, the backlight source 2 is provided with a fluorescent discharge lamp 20 on the side surface of a light guide plate 21 formed of a transparent material having a predetermined thickness such as an acrylic resin plate. The light L emitted from 20 is directed to the liquid crystal display element 1 from the diffusion plate 23, and is reflected by the reflection plate 22 to be directed from the diffusion plate 23 to the liquid crystal display element 1 direction to illuminate the liquid crystal display element 1. , Is configured to observe the image formed on the liquid crystal display element on the frame 4 side.

In order to effectively use the emitted light of the fluorescent discharge lamp 20, a member having a reflecting function has been provided outside in the past, but the internal loss of the fluorescent discharge lamp is large and the light utilization efficiency is high. It was extremely low.

The above-mentioned backlight light source includes the light guide plate 21.
The light of the fluorescent discharge lamp is directed to the liquid crystal display element by using the light guide body and the reflecting plate and the diffusing plate. There is also a structure in which the surface is used or the light guide plate is removed and an air layer is used as a light guide to propagate light.

The prior art relating to this type of liquid crystal display device is disclosed, for example, in Japanese Examined Patent Publication No. 51-13.
666 and JP-A-63-309921 can be mentioned.

[0016]

In the above-mentioned prior art, the fluorescent discharge lamp constituting the backlight light source is formed by applying a phosphor layer on the entire inner wall of a cylindrical tube. The visible light, which is emitted by stimulating the light with ultraviolet rays, is introduced into the light guide plate or the light guide body composed of the air layer.

Therefore, the light emitted in the direction of the light guide is
The light is mainly emitted from the part located on the light guide side of the fluorescent discharge lamp, and most of the other part of the light returns to the phosphor layer itself even if a reflection plate is provided outside. However, there is a problem that it is difficult to reduce the power consumption of the liquid crystal display device because it is attenuated by the absorption of light and its light utilization efficiency is extremely low.

It is an object of the present invention to provide a liquid crystal display device which solves the problems of the prior art and improves the light utilization efficiency of the illumination source.

[0019]

In order to achieve the above object, the invention according to claim 1 of the present invention comprises at least a liquid crystal display device and a backlight light source for illuminating the liquid crystal display device from the back surface. In the liquid crystal display element, the backlight light source is installed near the back surface of the liquid crystal display element, a light guide is installed along at least one side of the light guide, and the light guide is installed. It is characterized by comprising a dichroic mirror interposed between the body and the ultraviolet lamp on the side of the ultraviolet lamp, and a fluorescent film interposed on the side of the light guide.

The invention according to claim 2 of the present invention is
It is characterized in that the ultraviolet lamp comprises a reflective layer for reflecting the generated ultraviolet light on one of the outer wall surface and the inner wall surface excluding the surface facing the light guide.

The invention according to claim 3 of the present invention is characterized in that the dichroic mirror has a wavelength selection characteristic of substantially transmitting only ultraviolet rays.

Further, the invention according to claim 3 of the present invention is a liquid crystal display device comprising at least a liquid crystal display element and a backlight light source for illuminating the liquid crystal display element from the back surface, wherein the backlight light source is: A light guide installed near the back surface of the liquid crystal display element, an ultraviolet lamp installed along at least one side of the light guide, and the light guide between the light guide and the liquid crystal display element. It is characterized by comprising a dichroic mirror inserted on the body side and a fluorescent film inserted on the liquid crystal display element side.

In each of the above constructions, the dichroic mirror and the fluorescent film may be, for example, a phosphor coated on the surface of the dichroic mirror, or the fluorescent film may be coated on a separate transparent substrate. A protective film may be provided by covering the fluorescent film.

Further, the ultraviolet lamp has a reflective film formed except for the portion facing the light guide, but a separate reflecting plate or the like may be installed instead of this reflective film.

[0025]

In the above-mentioned structure of the present invention, the ultraviolet rays emitted from the ultraviolet lamp pass through the dichroic mirror and stimulate the fluorescent film.

The fluorescent film emits visible light rays by the stimulation of the ultraviolet rays, and the visible light rays are introduced into the light guide body, as shown in FIG.
As described in 3, the liquid crystal display element is illuminated from the back side.

Further, in the structure of the above-mentioned claim 2, it is generated by providing a reflection layer for reflecting generated ultraviolet rays on either the outer wall surface or the inner wall surface excluding the surface facing the light guide. Ultraviolet rays are directed toward the light guide without waste.

Further, in the structure of the above-mentioned claim 3, since the dichroic mirror has a wavelength selection characteristic that substantially only transmits ultraviolet rays, visible light emitted from the fluorescent film is reflected without returning to the ultraviolet lamp side. Therefore, the utilization efficiency of the illumination light is improved.

Further, in the structure of claim 4,
A dichroic mirror is provided on the liquid crystal display element side of the light guide, and a fluorescent film is provided between the dichroic mirror and the liquid crystal display element. Then, the ultraviolet rays from the ultraviolet lamps installed along at least one side of the light guide body stimulate the fluorescent film from the light guide body through the dichroic mirror. The visible light emitted from the fluorescent film is reflected by the dichroic mirror and returned to the liquid crystal display device.

As a result, the loss of light due to the interposition of the fluorescent film is eliminated, and the fluorescent film also functions as a diffusion plate, so that the illumination efficiency is improved as a whole.

The present invention is not limited to the above-mentioned constitution, and the present invention is not limited to the backlight light source for the liquid crystal display device, but can be applied to the surface light source of other electronic devices and the like. is there.

[0032]

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

FIG. 1 is a schematic view of a main part of a backlight light source part for explaining a first embodiment of a liquid crystal display device according to the present invention, in which 20a is an ultraviolet lamp, 20c is a reflective film, and 20d.
Is a fluorescent film, 20e is a dichroic mirror, and 21 is a light guide.

In the figure, the ultraviolet lamp 20a is a straight-tube mercury discharge lamp or the like, and its tube wall is transparent to ultraviolet rays. Around the tube wall, a reflection film 20c having a band-shaped opening along the side of the light guide 21 is provided.

The reflection film 20c is formed by vapor deposition or coating of aluminum or the like, or attachment of a light reflecting material such as aluminum foil.

It is preferable that the width of the strip-shaped opening is approximately equal to the thickness of the light guide 21 arranged in the vicinity thereof, but the width is not necessarily limited to this, and the width and the light guide are not limited thereto. The thickness of 21 may be different.

A dichroic mirror 20e and a fluorescent film 20d are interposed between the ultraviolet lamp 20a and the light guide 21. In this embodiment, the phosphor film 20d is formed by applying a phosphor to the surface of the dichroic mirror 20e on the light guide side to be integrated. The surface of the phosphor 20d may be covered with a protective film. The dichroic mirror 20e has wavelength selectivity in its transmission characteristic, and has a characteristic of transmitting in the ultraviolet region but blocking in the visible region and reflecting it.

In this embodiment, the ultraviolet lamp 20 is used.
The ultraviolet rays emitted from a are the dichroic mirror 20.
The fluorescent film 20d is stimulated through e to generate visible light. The generated visible light is reflected by the dichroic mirror 20e without returning to the direction of the ultraviolet lamp 20a and is directed to the direction of the light guide 21.

As described above, the phosphor film 20d is irradiated with ultraviolet rays generated by the excitation of mercury inside the ultraviolet lamp 20a by the reflection layer 20c in a substantially total amount thereof, and the visible light generated by the phosphor film 20d. Is the light guide 21
Since it is introduced into the liquid crystal display device, a high-luminance visible light can be applied to the liquid crystal display device.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

FIG. 2 is a schematic view of a main part of a backlight light source part for explaining a second embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in FIG. 1 correspond to the same parts.

In this embodiment, the dichroic mirror 20 is used.
e is provided in close contact with the band-shaped opening of the ultraviolet lamp 20a, and the fluorescent film 20d is applied to the light incident end of the light guide 21. A protective film may be formed on the surface of the fluorescent film 20d.

Also in the configuration shown in the figure, similarly, the ultraviolet rays emitted from the ultraviolet lamp 20a stimulate the fluorescent film 20d through the dichroic mirror 20e to generate visible rays. The generated visible light is reflected by the dichroic mirror 20e without returning to the direction of the ultraviolet lamp 20a and is directed to the direction of the light guide 21.

The ultraviolet rays from the ultraviolet lamp 20a are almost entirely projected by the reflecting layer 20c, and the fluorescent film 20
All the visible light generated in d is introduced into the light guide 21, so that high-luminance visible light can be applied to the liquid crystal display element.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

FIG. 3 is a schematic view of an essential part of a backlight light source part for explaining a third embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in FIGS. 1 and 2 correspond to the same parts.

In this embodiment, the dichroic mirror 2
0e is provided in close contact with the band-shaped opening of the ultraviolet lamp 20a, and the fluorescent film 20d is applied to cover the dichroic mirror 20e. A protective film may be formed on the surface of the fluorescent film 20d. Also in the configuration shown in the figure, similarly, the ultraviolet rays emitted from the ultraviolet lamp 20a stimulate the fluorescent film 20d through the dichroic mirror 20e to generate visible rays. The generated visible light is reflected by the dichroic mirror 20e without returning to the direction of the ultraviolet lamp 20a and is directed to the direction of the light guide 21.

The ultraviolet rays from the ultraviolet lamp 20a are almost entirely projected by the reflecting layer 20c, and the fluorescent film 20
All the visible light generated in d is introduced into the light guide 21, so that high-luminance visible light can be applied to the liquid crystal display element.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

FIG. 4 is a schematic view of an essential part of a backlight light source portion for explaining a fourth embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in the above embodiment correspond to the same portions.

In this embodiment, the reflecting layer 20c is formed on the inner tube wall of the ultraviolet lamp 20a so as to form a strip-shaped opening facing the light guide 21, and the dichroic mirror 20e is attached to the ultraviolet lamp 20a. It is provided inside the tube of the band-shaped opening, and the fluorescent film 20d is applied to the surface of this opening. A protective film may be formed on the surface of the fluorescent film 20d.

Also in the configuration shown in the figure, similarly, the ultraviolet rays emitted from the ultraviolet lamp 20a stimulate the fluorescent film 20d through the dichroic mirror 20e to generate visible rays. The generated visible light is reflected by the dichroic mirror 20e without returning to the inside of the ultraviolet lamp 20a and is directed toward the fluorescent film 20d.

The ultraviolet rays from the ultraviolet lamps 20a are almost entirely projected on the reflecting layer 20c, and the fluorescent film 20
All the visible light generated in d is introduced into the light guide 21, so that high-luminance visible light can be applied to the liquid crystal display element.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

FIG. 5 is a schematic view of an essential part of a backlight light source portion for explaining a fifth embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in the above embodiment correspond to the same portions.

In this embodiment, the fluorescent film 20d is connected to the light guide 2.
A dichroic mirror 20e is formed so as to cover the fluorescent film 20d while being applied to the first light incident end.

Also in the configuration shown in the figure, similarly, the ultraviolet rays emitted from the ultraviolet lamp 20a stimulate the fluorescent film 20d through the dichroic mirror 20e to generate visible rays. The generated visible light is reflected by the dichroic mirror 20e without returning to the direction of the ultraviolet lamp 20a and is guided to the direction of the light guide 21.

The ultraviolet rays from the ultraviolet lamp 20a are almost entirely projected by the reflecting layer 20c, and the fluorescent film 20
All the visible light generated in d is introduced into the light guide 21, so that high-luminance visible light can be applied to the liquid crystal display element.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

FIG. 6 is a schematic view of an essential part of a backlight light source portion for explaining a sixth embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in the above embodiments correspond to the same parts.

In this embodiment, the dichroic mirror 2
0e is provided in close contact with the band-shaped opening of the ultraviolet lamp 20a, and the fluorescent film 20d is applied to cover the dichroic mirror 20e.

Then, a transparent member such as a gel of a curable silicone resin or a resin such as polyester is injected between the fluorescent film 20d and the light guide 21 to remove the air layer.

Since the transparent member has flexibility, it is possible to avoid damage to the structural material due to mechanical strain between the ultraviolet lamp and the light guide due to temperature change or mechanical stress.

The injection into the transparent member shown in this embodiment can be applied to each of the above embodiments.

FIG. 7 is a schematic view of a main part of a backlight source for explaining a seventh embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in the above embodiments correspond to the same parts.

In this embodiment, instead of the reflection film in the embodiment shown in FIG. 5, a cylindrical reflector 20c 'formed separately from the ultraviolet lamp 20a is used.

Also in the configuration shown in the figure, similarly, the ultraviolet rays emitted from the ultraviolet lamp 20a stimulate the fluorescent film 20d through the dichroic mirror 20e to generate visible rays. The generated visible light is reflected by the dichroic mirror 20e without returning to the direction of the ultraviolet lamp 20a and is guided to the direction of the light guide 21.

The ultraviolet rays from the ultraviolet lamp 20a are almost entirely projected by the reflector 20c 'and the phosphor film 2
All visible light generated at 0d is introduced into the light guide 21, so that high-luminance visible light can be applied to the liquid crystal display element.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

Also in the configuration shown in the figure, similarly, the ultraviolet rays emitted from the ultraviolet lamp 20a stimulate the fluorescent film 20d through the dichroic mirror 20e to generate visible rays. The generated visible light is reflected by the dichroic mirror 20e without returning to the direction of the ultraviolet lamp 20a and is directed to the direction of the light guide 21.

The ultraviolet rays from the ultraviolet lamp 20a are almost entirely projected on the reflecting layer 20c, and the fluorescent film 20
All the visible light generated in d is introduced into the light guide 21, so that high-luminance visible light can be applied to the liquid crystal display element.

That is, the efficiency of the backlight light source becomes extremely high, and a bright liquid crystal display device can be constructed.

FIG. 8 is a schematic view of a main part of a backlight light source for explaining an eighth embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in the above embodiments correspond to the same parts.

In this embodiment, a reflecting film 20c, a fluorescent film 20d, and a dichroic mirror 20e are formed on a glass tube 20f which is separate from the ultraviolet lamp 20a, and this is installed as a jacket of the ultraviolet lamp 20a.

The dichroic mirror 20e shown in the figure may be provided on the ultraviolet lamp 20a side. Further, the fluorescent film 20d may be applied to the outer wall of the glass tube 20f.

The effects of this embodiment are similar to those of the above embodiments.

FIG. 9 is a schematic view of an essential part of a backlight light source portion for explaining a ninth embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in the above embodiments correspond to the same parts.

In this embodiment, the ultraviolet lamp 20a is
A flat surface portion 20g along the longitudinal direction of the tube body is provided on one side surface thereof, and a dichroic mirror 20e and a fluorescent film 20d are provided on the outer wall of the flat body portion 20g.

FIG. 10 shows a first example of the liquid crystal display device according to the present invention.
It is a principal part schematic diagram of the backlight light source part which demonstrates 0 Example, The same code | symbol as the said Example corresponds to the same part.

In this embodiment, the flat portion in the embodiment of FIG. 9 is formed substantially at the center along the tube axis of the tube of the ultraviolet lamp 20a, and the volume of the ultraviolet lamp can be greatly reduced. It is a thing.

FIG. 11 shows a first example of a liquid crystal display device according to the present invention.
FIG. 3 is a schematic view of a main part of a backlight light source portion for explaining one embodiment, and the same reference numerals as those in the above embodiment correspond to the same portions.

In this embodiment, the tube body of the ultraviolet lamp 20a has a substantially parabolic cross section, and the excited ultraviolet rays can be more efficiently concentrated in the phosphor layer 20d, further improving the wavelength conversion efficiency. Can be made.

The present invention is not limited to the above embodiments, and these configurations can be combined appropriately.

FIG. 12 shows a first example of the liquid crystal display device according to the present invention.
2 is a schematic view of a main part of a backlight light source portion for explaining a second embodiment, in which 1 is a liquid crystal display element, and the same reference numerals as those in the above embodiments correspond to the same portions.

In this embodiment, unlike the above-mentioned embodiments, the dichroic mirror 20e and the fluorescent film 20d are formed on the liquid crystal display element 1 side of the light guide 21.

That is, the ultraviolet lamp 20a has the reflecting film 2
0a is provided on the outer periphery, and the generated ultraviolet rays are introduced into the light guide 21.

On the other hand, a dichroic mirror 20e is installed on the liquid crystal display element side of the light guide 21, and a fluorescent film 20d is applied to cover the dichroic mirror 20e. A protective film may be formed on the upper surface of the fluorescent film 20d.

According to this structure, the ultraviolet rays from the ultraviolet lamp 20a are guided from the light guide 21 to the dichroic mirror 20.
The fluorescent film 20d is illuminated through the e. The fluorescent film emits visible light by this irradiation to illuminate the liquid crystal display element.

Since the dichroic mirror 20e substantially transmits only the ultraviolet region, visible light generated from the fluorescent film 20d is reflected by the dichroic mirror 20e and directed toward the liquid crystal display element.

Since the fluorescent film 20d also functions as a light diffusing film, the liquid crystal display element is uniformly illuminated.

The reflection film provided on the ultraviolet lamp 20a may be provided on the inner wall of the ultraviolet lamp 20a, or a separate reflection plate as shown in FIG. 7 or a jacket tube as shown in FIG. You may use what was done.

According to this embodiment, the loss of light due to the interposition of the fluorescent film is eliminated, and the fluorescent film also serves as the diffusion plate, so that the illumination efficiency is improved as a whole.

As described above, according to the configurations of the respective embodiments of the present invention, the brightness of the backlight can be greatly improved, so that it is possible to provide a liquid crystal display device having a bright screen with low power consumption.

[0094]

As described above, according to the present invention,
Since the luminous efficiency of the ultraviolet lamp or the utilization efficiency of the phosphor can be increased to significantly improve the luminance, it is possible to obtain a liquid crystal display device having a bright screen with low power consumption.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a backlight light source part for explaining a first embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a schematic diagram of a main part of a backlight light source portion for explaining a second embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is a schematic diagram of a main part of a backlight light source portion for explaining a third embodiment of the liquid crystal display device according to the present invention.

FIG. 4 is a schematic diagram of a main part of a backlight light source part for explaining a fourth embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a schematic view of a main part of a backlight light source portion for explaining a fifth embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is a schematic diagram of a main part of a backlight light source part for explaining a sixth embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is a schematic view of a main part of a backlight light source section for explaining a seventh embodiment of the liquid crystal display device according to the present invention.

FIG. 8 is a schematic view of a main part of a backlight light source portion for explaining an eighth embodiment of the liquid crystal display device according to the present invention.

FIG. 9 is a schematic view of a main part of a backlight light source section for explaining a ninth embodiment of the liquid crystal display device according to the present invention.

FIG. 10 is a schematic view of a main part of a backlight light source section for explaining a tenth embodiment of the liquid crystal display device according to the present invention.

FIG. 11 is a schematic view of a principal part of a backlight source part for explaining an eleventh embodiment of the liquid crystal display device according to the present invention.

FIG. 12 is a schematic view of a principal part of a backlight light source part for explaining a twelfth embodiment of the liquid crystal display device according to the present invention.

FIG. 13 is a developed perspective view illustrating a structural example of a liquid crystal display device.

FIG. 14 is a schematic cross-sectional view illustrating an example of the arrangement of each member that configures the liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2 Backlight light source 3 Printed circuit board 4 Frame 6,7 Spacer 9 Fixing piece 10 Slit 20 Fluorescent discharge lamp 20a UV lamp 20b Power supply terminal 20c Reflective film 20d Fluorescent film 20e Dichroic mirror 21 Light guide (light guide plate) 22 Reflector 23 Diffuser 24 Socket 25 Feed line 28 Connector 31 Control IC 32 Drive IC 41 Rim.

Claims (4)

[Claims] 1. A liquid crystal display element comprising at least a liquid crystal display element and a backlight light source for illuminating the liquid crystal display element from the back surface thereof, wherein the backlight light source is installed close to the back surface of the liquid crystal display element. A light guide, an ultraviolet lamp installed along at least one side of the light guide, a dichroic mirror interposed on the ultraviolet lamp side between the light guide and the ultraviolet lamp, and the light guide side. A liquid crystal display device, comprising: 2. The ultraviolet lamp according to claim 1, wherein:
A liquid crystal display device comprising a reflection layer for reflecting generated ultraviolet rays on one of an outer wall surface and an inner wall surface except a surface facing the light guide. 3. The liquid crystal display device according to claim 1, wherein the dichroic mirror has a wavelength selection characteristic of substantially transmitting only ultraviolet rays. 4. A liquid crystal display device comprising at least a liquid crystal display element and a back light source for illuminating the back surface of the liquid crystal display element, wherein the back light source is installed close to the back surface of the liquid crystal display element. A light guide, an ultraviolet lamp installed along at least one side of the light guide, a dichroic mirror interposed on the light guide side between the light guide and the liquid crystal display element, and the liquid crystal. A liquid crystal display device comprising a fluorescent film interposed on the display element side.