JPH08122782A - Backlight for liquid crystal panel - Google Patents

Abstract

PURPOSE: To secure visual homogenization in addition to the numerical homogenization of luminance on an irradiation surface by restraining the shadow caused by direct light from a light source. CONSTITUTION: The inner surface 12b of a main body 12 in which the light source 14 is arranged is formed as a diffuse reflection surface where light is diffused in many directions by irregular reflection. A diffuse reflector 20 diffusing the light in many directions by the irregular reflection is formed as a light transmissive diffuse reflector having a transmitting surface 20a through which the light is transmitted and interposed between the light source 14 and a diffuse transmission plate 18(18-1 and 18-2). Many slits orthogonally crossed with the axial line of the light source 14 and separated at equal intervals in the axial direction of the light source are formed on the transmitting surface 20a of the diffuse reflector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight for a liquid crystal panel, which irradiates the back surface of the liquid crystal panel with light from a linear light source to secure the brightness of the display surface of the liquid crystal panel.

[0002]

2. Description of the Related Art For example, a liquid crystal panel has been widely used in recent years as a display for a notebook type or laptop type personal computer (personal computer), a word processor (word processor), a portable TV, a portable video game, a car navigation system, and the like. Has been done.

In general, since the liquid crystal panel does not emit light itself, a proper brightness, that is, brightness is obtained on the display surface of the liquid crystal panel by combining it with an auxiliary illumination called a backlight installed on the back surface.

The backlight is a liquid crystal, for example, by reflecting light from a light source built in a body having a substantially box shape, by reflecting the light in the body and diffusing the light by a diffusion / transmission plate provided in the body opening. It is configured to uniformly illuminate the entire back surface of the panel. As a backlight like this,
For example, a so-called inner light type (direct type) in which one or more light sources are arranged in a position aligned with the main body opening.
And a so-called sidelight type in which a plurality of or a single light source having the same light amount is arranged at opposite ends of the main body are generally well known.

Here, in such a backlight, for example, a translucent reflection plate partially having a transmission surface through which light can be transmitted is interposed between the light source and the diffusion transmission plate,
The deviation of the light transmission amount at each portion is suppressed by adjusting the light transmission amount at the portion near and far from the light source by the reflecting plate. The transmissive surface of such a reflector is generally formed in a slit shape extending along the axis of the light source, and the amount of light transmission at the portion near the light source and the portion far from the light source is adjusted by changing the slit width, pitch, etc. It is carried out.

[0006]

Here, as shown in FIG. 10, in a known backlight 310 of a liquid crystal panel, light from a light source 314 is normally emitted radially from the center in the radial direction of the light source. Only the light aligned on the transmissive surface 320a of the reflection plate is directly transmitted through the reflection plate 320 for each transmission surface and is incident on the diffuse transmission plate 318. Therefore, the back surface portion of the reflection surface 320b of the reflection plate (shaded area in the figure). No direct light is incident on the part).

Therefore, in the known configuration, the main body 312
By irradiating the diffused light diffused on the inner surface 312b of the light source 320a from the transmissive surface 320a of the reflector,
The brightness of the back surface of 320b is secured, and the light from the reflection plate is further diffused by the diffuse transmission plate 318, so that the brightness on the irradiation surface 316 is kept uniform. According to the backlight having such a known structure, since the diffuse transmission plate 318 diffuses light over the entire irradiation surface 316, numerical homogenization of the luminance on the irradiation surface can be obtained.

However, the shadow generated by the direct light from the light source 314 is dark, and the luminous intensity of the reflected light emitted after being reflected in the main body is lower than that of the direct light from the light source. It is difficult to cancel the shadow caused by the light under the interference with the reflected light, and there is a possibility that the shadow cannot be sufficiently erased even after being diffused by the diffuse transmission plate. That is, the shadow generated by the reflection surface 320b of the reflection plate may remain on the irradiation surface 316 in a visually recognizable state.

In a backlight of a liquid crystal panel, in addition to numerical homogenization of brightness, visual homogenization within a predetermined angle range is required, so that shadows cannot be sufficiently erased. Inevitable quality deterioration.

The present invention provides a backlight for a liquid crystal panel, which suppresses the generation of shadows due to the direct light from a light source, and obtains visual homogenization in addition to numerical homogenization of the brightness of the irradiation surface. It is an object.

[0011]

In order to achieve this object, in the present invention, attention is paid to that light from a linear light source is radiated in multiple directions even in the axial direction of the light source,
The direct light emitted in the axial direction of the light source is caused to interfere with each other at the portion where the shadow is generated, thereby suppressing the generation of the shadow.

That is, according to the present invention, the inner surface of the main body is formed as a diffuse reflection surface for diffusing light in multiple directions by diffuse reflection, the light source is arranged at a predetermined position in the main body, and the light is diffused by diffuse reflection. A diffuse reflection plate that diffuses in multiple directions is formed as a translucent diffusion reflection plate having a light-transmitting transmission surface, and is interposed between the light source and the diffusion transmission plate. Further, the transmission surface of the diffuse reflection plate is in the form of a slit having a specific width orthogonal to the axis of the light source, and is formed in large numbers in the direction of the axis of the light source while being equally spaced.

[0013]

According to this structure, since the direct light from the light source passes through the slit-shaped transmission surface of the translucent diffuse transmission plate and is irradiated in multiple directions along the axis of the light source, the shadow generated by the reflection surface is generated. Are suppressed by the mutual interference of the direct rays of light from the adjacent transmission surfaces, and are canceled by the diffusion of the light by the diffuse transmission plate. Therefore, the unevenness of the brightness caused by the shadow can be sufficiently suppressed, and the homogenization of the brightness on the irradiation surface can be ensured not only numerically but also visually.

[0014]

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

As shown in FIGS. 1 and 2, a liquid crystal panel backlight 10 according to the present invention includes a linear light source 14 built in a main body 12 and emits light from the light source from an irradiation surface 16. Is configured to.

The backlight 10 is usually formed as an auxiliary illumination for giving appropriate brightness (brightness) to a liquid crystal panel (not shown) for displaying characters, pictures, etc. so that the liquid crystal panel can be illuminated from the back side. . Then, by combining the liquid crystal panel and the backlight 10, a notebook-type or laptop-type personal computer (personal computer) or word processor (word processor) having appropriate brightness on the display surface, a portable TV, a portable video game and car navigation. A display used for the system is configured.

As can be seen from FIG. 2 in addition to FIG.
The main body 12 of the backlight is formed, for example, in a substantially box shape having an opening 12a on the upper surface in the figure. Then, for example, a plurality of light sources 14 having the same light quantity are juxtaposed and fixed in the range aligned with the main body opening 12a while being equally spaced apart.

As the light source 14, for example, a general non-directional cold cathode tube can be used. In the embodiment, the light source is 6
Book is provided.

In addition, light is transmitted while being diffused in multiple directions, for example, two diffuse transmission plates 18 (18-1, 18-2).
Are placed so as to overlap the opening 12a of the main body. As the diffusion transmission plate 18 (18-1, 18-2), for example, any diffusion sheet capable of diffusing light by embossing can be used.

In such a structure, the light emitted from the inside of the main body 12 is sequentially diffused by the diffuse transmission plate 18 (18-1, 18-2) and then is irradiated on the back surface of the liquid crystal panel. That is, in such a backlight 10, the upper surface of the upper diffused transmission plate 18-2 is formed as an irradiation surface 16 that irradiates the back surface of the liquid crystal panel with light of uniform brightness.

In the embodiment, the diffusion sheet formed by embossing is exemplified as the diffusion transmission plate 18 (18-1, 18-2), but it is sufficient if it diffuses incident light and transmits it. Therefore, the present invention is not limited to the diffusion sheet, and for example, a prism sheet may be used as the diffusion transmission plate.

Here, in the present invention, the inner surface of the main body
12b is formed as a diffuse reflection surface that diffuses light in multiple directions by irregular reflection. The diffuse reflection surface is usually formed by unevenness by embossing or surface treatment such as application of high-concentration special ink.

As shown in FIGS. 1 and 2, in the present invention, for example, the diffuse reflection plate 20 which is a diffuse reflection surface similar to the inner surface 12b of the main body is a transmission surface through which light can be transmitted.
Light source 14 formed as a translucent diffuse reflector with 20a
And the diffuse transmission plate 18 are interposed. As can be seen from FIG. 3, the transmission surface 20a of the diffuse reflection plate (translucent diffusion reflection plate) has a slit shape orthogonal to the axis of the light source 14,
A large number of light sources are formed in the axial direction of the light source while being equally spaced.

As shown in FIG. 1, in such a structure, the light (direct light) from the light source 14 is first radiated in all directions around the light source, and the reflecting surface 20b of the diffuse reflection plate and the main body. Under the multi-directional diffusion due to reflection on the inner surface 12a,
Propagated over a wide area inside the body. Then, of the direct light from the light source 14 and the reflected light that has been reflected by the inner surface 12b of the main body, only the light that is aligned with the transmissive surface 20a of the diffuse reflective plate passes through the transmissive surface and is diffused and transmissive plate 18 (18-1). Is incident on.

Here, the light from the light source 14 is emitted in multiple directions even in the axial direction of the light source. And the light source 14
Since direct light from all angles in the axial direction of ∘ enters a wide range for each transmission surface 20a of the diffuse reflection plate, as shown in FIG. They interfere with each other on the backside of surface 20b.

As described above, in the present invention, since lights having the same luminous intensity interfere with each other on the back surface of the reflecting surface 20b, the shadow generating portion is sufficiently suppressed as shown by the shaded area in FIG. Becomes lighter.

The light transmitted through the diffuse reflection plate 20 is sequentially incident on the diffuse transmission plate 18 (18-1, 18-2) and further diffused in multiple directions. The faint shadow generated in the area is easily canceled, and thus the unevenness of the brightness on the upper surface of the upper diffuse reflection plate 18-2, that is, the irradiation surface 16 due to the shadow is surely prevented.

By the way, in such a backlight 10, a difference in illuminance at a position near the light source 14 and at a position far from the light source 14 cannot be avoided. Therefore, as shown in FIG. 3, in the present invention, in the transmission surface 20a of the diffuse transmission plate, the light transmittance in the range X1 located above the light source 14 is the other portion, that is, the adjacent light source. It is set lower than the light transmittance in the range X2 located between them. That is, the transmission surface 20a of the diffusion transmission plate
, The range X1 where the direct light from the light source 14 is likely to enter
The width L2 of the transparent surface of the part is the width L3 of the transparent surface of the range X2
It is formed narrower.

For example, when the diameter of the light source 14 is 4.1 mm and the pitch between adjacent light sources is 50 mm, the pitch L1 of the transparent surface 20a is 3.5 mm, the width L2 of the transparent surface range X1 is 0.6 mm, The width L3 of the range X2 is set to about 1/18 inch, and the range X1 of the transmitting surface is formed to a length of about 1/6 inch with the center aligned with the light source.

With this structure, the transmission of light in the area X1 close to the light source 14 is suppressed, and the light shielded by the diffuse reflection surface 20b is diffused in multiple directions due to irregular reflection and is brought to a far portion. Therefore, sufficient illuminance can be secured in the range X2 between the light sources that mainly transmits the reflected light from the inner surface 12b of the main body. Therefore, the unevenness of the illuminance at the portion near the light source 14 and the portion far from the light source 14 is sufficiently suppressed.

The diffuse reflection plate 20 is, for example, the light source 14
Diameter, the distance from the bottom of the body 12 to the light source, the transparent surface 20b
The distance between the light source and the light source is determined by the correlation such as the width of the light source. For example, in a backlight of a size corresponding to a 21-inch liquid crystal panel, the diameter of the light source 14 is
4.1mm, 6.0mm distance from the bottom of the body to the center of the light source
, If the width of the transmission surface 20a in the range X1 is set to about 0.6 mm, the distance from the center of the light source to the bottom surface of the diffuse transmission plate 20 is 3.
It is set to about 0 mm.

As described above, in the backlight 10 of the liquid crystal panel of the present invention, the transmissive surface of the translucent diffuse reflection plate is used.
20a is formed in a slit shape orthogonal to the axis of the light source 14, and the direct rays emitted in the axis direction of the light source interfere with each other,
The shadow generated by the reflecting surface 20b is sufficiently suppressed. Therefore, the diffusion of the light in the diffuse transmission plate 18 (18-1, 18-2) to be performed later makes it possible to sufficiently cancel the shadow, and visual unevenness on the irradiation surface 16 can be reliably prevented.

Since the light transmittance in the range X1 located above the light source 14 is set to be lower than that in the far range X2,
It is possible to sufficiently prevent the unevenness of the illuminance due to the distance from the light source, and it is possible to easily ensure the homogenization of both the visual and numerical brightness over the entire irradiation surface. Therefore, the quality of the backlight 10 of the liquid crystal panel is surely improved.

Further, since the transmissive surface 20a is formed in a slit shape orthogonal to the axis of the light source 14, the direct light emitted in the radial direction of the light source can be effectively used, which is peculiar to the inner light type backlight. High brightness can be sufficiently ensured on the irradiation surface 16. Therefore, with such a configuration, it becomes possible to reduce the power consumption of the backlight 10, and
The backlight 10 of the present invention can be effectively used for a color liquid crystal panel that requires high brightness on the irradiation surface 16.

The numerical values illustrated in this embodiment are merely examples in the case where the diameter, pitch, etc. of the light source are assumed as described above, and the numerical values of the respective parts are not limited to this.

In the embodiment, two diffuse transmission plates 18 (18-1, 18-2) are arranged in the main body opening 12a.
Since it suffices to diffuse the light from the diffuse reflection plate 20 and irradiate it uniformly, it is possible to use only one diffuse transmission plate. Diffuse reflector
The number of 18 is adjusted and set according to the degree of unevenness of the brightness on the irradiation surface 16.

Further, in the embodiment, the configuration in which the six light sources 14 are arranged is illustrated, but the number of light sources is not limited to this, and for example, the number of light sources can be changed according to the required luminous intensity. May be adjusted. In this case, the pitch between the light sources 14,
That is, it goes without saying that the range X2 of the transmissive surface 20a changes with the pitch of the light source.

Although a cold cathode tube is shown as an example of the light source 14, any other hot cathode tube, cold cathode tube or the like may be used as the light source as long as it can emit light in a linear shape. . However, since the cold cathode tube is superior to other cathode tubes in terms of heat and life, it is preferable to use the cold cathode tube as a light source.

Here, in the embodiment, a plurality of light sources 14
However, the present invention is not limited to this, and as shown in FIG. 5, for example, a single light source or a plurality of light sources may be arranged in the central portion of the main body 12. Here, two light sources 14 juxtaposed side by side are arranged in the center of the main body 12. And, as in the previous embodiment,
The diffuse transmission plate 18 (18-1, 18-2) and the diffuse reflection plate 120 are arranged so as to overlap the main body opening 12a.

As shown in FIG. 6, even in the diffuse transmission plate 120 in such a backlight 110, the transmission surface 120a
Is formed in a slit shape in a direction orthogonal to the axis of the light source 14 and has a width L2 of a range X1 located above the light source narrower than a width L3 of another range X2.

Even in such a configuration, the direct light emitted from the light source 14 emitted in the axial direction of the light source 14 interferes with each other after passing through the transmission surface 120a of the diffuse transmission plate, so that the shadow of the reflection surface 120b is generated. Formation is suppressed. Then, of the transmission surface 120a of the diffuse reflection plate, since the transmittance in a predetermined range X1 located above the light source 14 is set lower than the range X2 of other portions, the light source is the same as in the above embodiment. The deviation of the illuminance due to the distance from can be sufficiently prevented, and the homogenization of both the visual and numerical luminance in the entire irradiation surface can be easily ensured.

In FIGS. 5 and 6, the light source 14 is set to 2
Although a configuration in which the light sources are arranged side by side is illustrated, the number of light sources is not limited to two because they may be arranged in the central portion of the main body 12, and may be, for example, one or three to four. Also in the backlight 110 having this configuration, the number of light sources is set according to the required luminous intensity and the like.

In addition, a predetermined range located above the light source 14
X1 is appropriately set according to the number of light sources, that is, the effective width of the light sources.

In the above embodiment, the light source 14 or the light sources 14 are arranged at the position aligned with the opening 12a of the main body.
Although a backlight is exemplified as the so-called inner light type structure, the structure is not limited to the inner light type structure, and for example, a so-called side light type backlight in which light sources are respectively arranged at opposite side end portions of the main body. To
The present invention may be applied.

As shown in FIG. 7, in the sidelight type backlight 210, the light source 14 having the same light quantity is used in the main body 12
Are arranged at the opposite side ends of each. Then, similarly to the above-mentioned embodiment, the diffuse transmission plate 18 (18-1, 18-2) and the diffuse reflection plate 220 are arranged so as to overlap with the main body opening 12a.

Here, as shown in FIG. 8, also in this sidelight type backlight 210, the transmission surface 220a of the diffuse reflection plate is formed in a slit shape orthogonal to the axis of the light source 14, but here, By providing a difference in the widths L2 and L3 of the transmissive surface, the light transmittance in the specified range X1 of the side edge near the light source is lower than the light transmittance in the other range, that is, in the center range X2. It is set.

Even in such a configuration, as in the above-described embodiment, the mutual interference of the direct rays of light emitted in the axial direction of the light source 14 suppresses the formation of a shadow by the reflecting surface 220b of the diffuse reflector. Then, of the transmission surface 220a of the diffuse reflector,
Since the transmittance in the predetermined range X1 located at the side end close to the light source 14 is set to be lower than the range X2 of the other part, the unevenness of the illuminance due to the distance from the light source is similar to the above embodiment. Can be sufficiently prevented, and homogenization of both visual and numerical brightness can be easily ensured over the entire irradiation surface.

The light source 14 disposed at the opposite end of the main body 12
Are not limited to the configuration in which one light source is arranged at each side end portion as shown in the figure, as long as they have the same light amount. For example, two or more light sources are arranged at each side end portion. The same number may be arranged.

Here, as shown in FIGS. 3, 6 and 8, the transmission surfaces 20a, 120a and 220a of the diffuse reflection plate in all of the above-mentioned embodiments are within the range X1 of the portion close to the light source 14. width
It is formed in a shape that directly connects L2 and the width L3 of the range X2 of the far portion. That is, the transmissive surfaces 20a, 120a, 220a of the diffuse reflectors are formed as a shape that divides the boundary between the width L2 of the range X1 and the width L3 of the range X2 at a right angle.

However, the present invention is not limited to this, and for example, as shown in FIG. 9, the transmission surfaces 20a and 120a of the diffuse reflection plate are formed by tapering the width L2 of the range X1 and the width L3 of the range X2. 220a
May be formed.

In such a structure, the transmission surface of the diffuse reflector is
The light transmittance in the range X1 and range X2 of 20a, 120a, 220a does not change sharply at the boundary and gradually increases as it goes to a position farther from the light source 14. The amount of transmitted light can be adjusted accurately and easily. Therefore, the numerical and visual homogenization of the luminance on the irradiation surface 16 is further enhanced.

In the above configuration in which the width L2 of the range X1 and the width L3 of the range X2 are connected by the tapered portion, the light source 14 is provided in the central portion of the main body 12 as shown in FIGS. It can be particularly effectively used for a side-light type configuration shown in FIGS. 7 and 8 provided at the side end portion, that is, a backlight in which light from a light source is transmitted farther.

The transmission surfaces 20a, 120a, 220a of the diffuse reflection plate
The range (length) of the tapered portion may be appropriately adjusted depending on the arrangement of the light source 14 and the like.

The above-mentioned embodiments are for explaining the present invention and do not limit the present invention in any way.
It goes without saying that the present invention includes all those which are modified or modified within the technical scope of the present invention.

[0055]

As described above, according to the backlight of the liquid crystal panel of the present invention, due to the mutual interference of the direct light emitted in the axial direction of the light source, the shadow is formed by the reflecting surface of the diffuse reflection plate. Since the light is suppressed, the shadow can be sufficiently canceled by the diffusion of the light in the diffuse transmission plate later. Therefore, it is possible to reliably prevent the unevenness of the brightness due to the shadow.

Since the light transmittance in a predetermined range located above the light source is set to be lower than that in other areas far away from the light source, deviation in illuminance due to the distance from the light source can be sufficiently prevented. Therefore, it is possible to easily ensure the homogenization of both the visual and numerical brightness over the entire irradiation surface, and the quality of the backlight is surely improved.

Furthermore, since it suffices if the transmission surface of the diffuse reflection plate is formed in a slit shape orthogonal to the axis of the light source, the structure is not complicated.

Since it suffices to set the light transmittance in a predetermined range located above the light source to be lower than the other range far away from the light source, a plurality of light sources are arranged side by side with equal intervals, and a single light source or a plurality of light sources are arranged. The above effect can be sufficiently obtained in both the configuration in which the light source is arranged in the central portion of the main body and the configuration in which the light sources having the same light amount are arranged at the opposite side end portions of the main body.

If the transmission surface of the diffuse reflector is formed by tapering the width of the range near the light source and the width of the range away from the light source, the range of the range close to the light source and the range of the range far from the light source are formed. The transmittance of the light does not change sharply at the boundary portion and gradually increases toward the position farther from the light source, so that the amount of light transmission related to the position from the light source can be accurately and easily adjusted. Therefore, the numerical and visual homogenization of the brightness on the illuminated surface can be further improved.

If at least an interval derived from the correlation between the diameter of the light source, the distance from the bottom surface in the main body to the light source, and the width of the transmission surface of its own is provided between the light source and the diffuse reflection plate, Reflection, transmission of light according to these requirements,
Since diffusion and the like can be accurately obtained, uniform brightness in which unevenness in brightness due to shadow elimination is suppressed can be sufficiently ensured over the entire irradiation surface.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a backlight of a liquid crystal panel according to an embodiment of the present invention in a direction along an axis of a light source.

FIG. 2 is a schematic exploded perspective view of a backlight of a liquid crystal panel.

FIG. 3 is a schematic perspective view of a diffuse reflection plate in a backlight of a liquid crystal panel with a part thereof cut away.

FIG. 4 is a partially enlarged view of a backlight of a liquid crystal panel.

FIG. 5 is a schematic vertical cross-sectional view of a backlight of a liquid crystal panel according to a modification of the present invention in a direction orthogonal to the axis of the light source.

FIG. 6 is a schematic perspective view of the diffuse reflection plate in the embodiment of FIG.

FIG. 7 is a schematic vertical cross-sectional view of a backlight of a liquid crystal panel according to another embodiment of the present invention in a direction orthogonal to the axis of the light source.

8 is a schematic perspective view of the diffuse reflection plate in the embodiment of FIG. 7 with a part thereof cut away.

FIG. 9 is a partially enlarged perspective view of a diffuse reflection plate showing a modified example of the shape of a transmission surface.

FIG. 10 is a partially enlarged view of a backlight of a conventional liquid crystal panel.

[Explanation of symbols]

 10, 110, 210 Liquid crystal panel backlight 12 Main body 12a Main body opening 12b Main body inner surface (diffuse reflection surface) 14 Light source 16 Irradiation surface 18 (18-1, 18-2) Diffuse transmission plate 20, 120, 220 (Transmission) Diffuse reflector 20a, 120a, 220a Diffuse reflector transmission surface 20b, 120a, 220b Diffuse reflector reflection surface

Claims (6)

[Claims] 1. A linear light source is built in a substantially box-shaped main body, and a diffusion transmission plate that transmits light while being diffused in multiple directions is provided in the main body opening. In the backlight of the liquid crystal panel that secures the brightness of the display surface of the liquid crystal panel by irradiating the back surface of the liquid crystal panel with the light of, the inner surface of the main body is formed as a diffuse reflection surface that diffuses light in multiple directions by irregular reflection. At the same time, the light source is arranged at a predetermined position in the main body, and the diffuse reflection plate that diffuses light in multiple directions by diffuse reflection is formed as a light-transmitting diffuse reflection plate having a transmissive surface through which light can pass. It is characterized in that it is interposed between the diffuse transmission plate and the transmission surface of the diffusion reflection plate is formed in a slit shape orthogonal to the axis of the light source, and is formed in large numbers with equal intervals in the axial direction of the light source. LCD panel Backlight. 2. A linear light source is built in a substantially box-shaped main body, and a diffusion transmission plate that transmits light while being diffused in multiple directions is provided in the main body opening. In the backlight of the liquid crystal panel that secures the brightness of the display surface of the liquid crystal panel by irradiating the back surface of the liquid crystal panel with the light of, the inner surface of the main body is formed as a diffuse reflection surface that diffuses light in multiple directions by irregular reflection. At the same time, a plurality of light sources with the same light quantity are juxtaposed in parallel with each other within the range aligned with the opening of the main body with equal spacing, and a diffuse reflection plate that diffuses light in multiple directions by irregular reflection has a transparent surface that can transmit light. It is formed as a translucent diffuse reflection plate and is interposed between the light source and the diffusion transmission plate, and the transmission surface of the diffusion reflection plate is a slit shape orthogonal to the axis of the light source, and is equally spaced in the axial direction of the light source. And many are formed In addition, the backlight of the liquid crystal panel is characterized in that the transmittance of light in a predetermined range located above each light source on the transparent surface is set to be lower than the transmittance of light in other ranges. . 3. A linear light source is built in a substantially box-shaped main body, and a diffusion transmission plate that transmits light while being diffused in multiple directions is provided in the main body opening. In the backlight of the liquid crystal panel that secures the brightness of the display surface of the liquid crystal panel by irradiating the back surface of the liquid crystal panel with the light of, the inner surface of the main body is formed as a diffuse reflection surface that diffuses light in multiple directions by irregular reflection. At the same time, a single or multiple light sources are arranged in the center of the body, and a diffuse reflector that diffuses light in multiple directions by diffuse reflection is formed as a translucent diffuse reflector having a transparent surface through which light can pass. The transmission surface of the diffuse reflection plate, which is interposed between the light source and the diffuse transmission plate, is formed in a slit shape orthogonal to the axis of the light source, and is formed in a number of directions that are equally spaced in the axial direction of the light source. Out of face A backlight of a liquid crystal panel, characterized in that the light transmittance in a predetermined range located above the light source is set lower than the light transmittance in other ranges. 4. A linear light source is built in a substantially box-shaped main body, and a diffusion transmission plate that transmits light while being diffused in multiple directions is provided in the main body opening. In the backlight of a liquid crystal panel that secures the brightness of the display surface of the liquid crystal panel by irradiating the back surface of the liquid crystal panel with the light of, the inner surface of the main body is formed as a diffuse reflection surface that diffuses light in multiple directions by diffuse reflection. At the same time, a single or multiple light sources with the same light amount are arranged at the opposite side ends of the main body, and a diffuse reflection plate that diffuses light in multiple directions by diffuse reflection has a light-transmitting transparent surface. It is formed as a diffusive diffuse reflection plate and is arranged on the diffuser transmission plate at the light source side, and the transmission surface of the diffuse reflection plate has a slit shape orthogonal to the axis of the light source and is equally spaced in the axial direction of the light source. Majority The liquid crystal is characterized in that the transmittance of light in a predetermined range of the transparent surface located on the side end near the light source is set lower than the transmittance of light in other parts of the transparent surface. Backlight of the panel. 5. The back of a liquid crystal panel according to claim 2, wherein the transmissive surface of the diffuse reflection plate is formed by connecting the width of the range near the light source and the width of the range far from the light source in a tapered shape. Light. 6. A translucent diffuse reflector keeps at least a distance derived from the correlation between the diameter of the light source, the distance from the bottom surface in the body to the light source, and the width of the transparent surface of the light source to the light source. The backlight for a liquid crystal panel according to claim 1, wherein the backlight is arranged as a unit.