JP3365529B2 - 3-color backlight light source - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-color backlight light source for a color panel display device, and more particularly to a display section having a pixel area whose light transmittance changes according to image information. The present invention relates to a three-color backlight light source for selectively supplying backlights of R, G, and B colors.

[0002]

2. Description of the Related Art In recent years, personal computers and other O
As home appliances such as A-equipment and televisions become lighter and thinner, display devices are also required to be lighter and thinner. Therefore, C which is more popular than before
As an alternative to RT, a liquid crystal display (LCD),
The magnetic fluid display according to the applicant (Japanese Patent Application No. 5-
Development of lightweight and thin flat panel displays such as No. 191787 and Japanese Patent Application No. 5-270063) is under way.

Full-colorization is one of the technical items required for these flat panel displays. For example, as shown in FIG. 5, a TFT type color liquid crystal display device 100 has a structure in which two glass substrates 101 and 102 are opposed to each other with a space of several μm therebetween and fixed, and a liquid crystal 103 is sealed in the gap. Has become. The signal line 10 is formed on the lower glass substrate 102.
4 and the scanning lines 105 are arranged in a matrix, and a TFT 106 and a transparent pixel electrode 107 are connected to the intersections thereof. A common electrode 108 and a color filter 109 are arranged on the upper glass substrate 101.
When this TFT-LCD is sandwiched by two deflecting plates 110 and 111 and a white light source 112 is made incident as a backlight, a transmissive display device is obtained. The color filter is R
It is composed of three primary colors of (red), G (green), and B (blue), and is arranged corresponding to each pixel electrode 107. And, for example, R
When is turned on, color display is performed by making the R region transparent and the G and B regions non-transparent. The color filter type color panel display as described above has been widely adopted since the full color display of the panel display is relatively easy.

Recently, for example, Japanese Patent Laid-Open No. 4-33
No. 8996 discloses a full-color image by sequentially turning on independent light sources for each of R, G, and B colors and adding a corresponding color signal to each pixel in synchronization with the lighting period. , R,
A three-color backlight type color panel display using light sources of G and B colors has been proposed.

[0005]

However, according to the conventional color filter type color panel display, pixels corresponding to each color of R, G and B of the color filter are required, so that the degree of integration of the pixel density is increased. However, there are limitations, and it has been difficult to obtain higher density color images. Furthermore, the color filter method has a problem that the yield is poor because the pixel density is three times as high as that of the monochrome display method. Further, in the panel display of the three-color backlight system as described above, R, G,
There is a problem that a monochromatic light source corresponding to each B color must be used.

Therefore, an object of the present invention is to obtain a higher density color image than a conventional color filter type color panel display by using a white light source, and
An object of the present invention is to provide a three-color backlight light source that can be colored by simply replacing the backlight light source of a conventional monochrome display.

[0007]

In order to solve the above-mentioned problems, a display unit having a pixel region whose light transmittance changes according to image information according to claim 1, Accordingly, the three-color backlight light source for selectively supplying the backlights of B, G, and R colors is a white light source for B, G
A white light source for R and a white light source for R, and a spectroscopic means for injecting white light emitted from each of the light sources, respectively, and B light of the decomposed light of the white light source for B emitted from the spectroscopic means, The white light source for B, the white light source for G, and the R light so that G light of the decomposed light of the white light source for G and R light of the decomposed light of the white light source of R enter the incident surface of the display unit. It is characterized in that white light sources for use are arranged.

In the three-color backlight light source according to a second aspect of the invention, the white light emitted from each of the light sources is incident on the spectroscopic means via the parallel light incident means that causes the white light to enter the spectroscopic means as parallel light. It is characterized by that.

Further, in the three-color backlight light source described in claim 3, the spectral means is a spectral prism.

Further, the three-color backlight light source according to a fourth aspect is characterized in that the incident surface is a side surface of the display section.

Further, in the three-color backlight light source according to a fifth aspect, the display section is a monochrome panel display.

[0012]

According to the three-color backlight light source described in claim 1, B light of the decomposed light of the B white light source emitted from the spectroscopic means, G light of the decomposed light of the G white light source, and R
The white light source for B, the white light source for G, and the white light source for R are arranged so that R light of the decomposed light of the white light source for light enters the incident surface of the display unit. B, G, and R lights can be supplied to the display unit. Therefore, the pixels for the R, G, and B regions of the color filter of the display unit are not necessary. Therefore, the yield can be improved, and full color can be obtained by simply replacing the backlight of the conventional monochrome display.

According to the three-color backlight light source of claim 2, since the white light source can be incident on the spectroscopic means as parallel light, stray light due to light incident from other than parallel light can be prevented, and R, G, B can be prevented. The monochromaticity of each color can be increased.

According to the three-color backlight light source of claim 4, since the white light source can be located laterally of the display portion, it is thinner than the direct type in which the fluorescent lamp is arranged on the back surface side of the display portion. It is possible to make it uniform, and the uniformity of the brightness surface is also high.

According to the three-color backlight light source of the fifth aspect, since the color display can be constructed by using the monochrome panel display, the versatility of the display section can be enhanced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a three-color backlight light source constructed according to the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the three-color backlight light source 1 according to the first embodiment constructed according to the present invention is
White light source 2B, G white light source 2G, and R white light source 2R, and a triangular prism 3 which is a spectroscopic means for injecting the white light W emitted from the white light source 2, respectively.

The triangular prism 3 has substantially the same length as the white light source 2, and has at least two side surfaces 3a,
3b is optically polished. An antireflection film for visible light may be formed on these polished surfaces.

As the white light source 2, a fluorescent tube is used in this embodiment. This fluorescent tube is of high color rendering type, namely B,
It is preferable to be a three-wavelength emission type using a phosphor material that makes emission of G and R wavelengths particularly strong. The fluorescent tube may be either a hot cathode type or a cold cathode type.
When the hot cathode type is used, both the electrode and the inverter are larger than when the cold cathode type is used, but the power loss near the electrode that does not contribute to light emission is small, so the efficiency is good and several times better. It has the advantage of exhibiting luminous efficiency and strong emission. When the cold cathode type is used, there is an advantage that it has a long life.

The white light source 2 has white light sources 2B and 2G for B from the top 3c to the bottom 3d of the triangular prism 3.
The white light source 2G for red and the white light source 2R for R are arranged in this order. That is, the B white light source 2B for extracting the B light having the shortest wavelength among the B, G, and R lights from the white light source is attached to the top 3
The G white light source 2G for extracting the G light having a short wavelength is arranged next to the bottom portion 3d of the B white light source 2B in parallel, and the R white light source 2R for the shortest wavelength is used for the G white light source 2G. They are arranged side by side near the bottom 3d. The intervals between the white light sources 2B, 2G, and 2R are such that the B light of the B white light source 2B described later, the G light of the G white light source 2G described later, and the R light of the R white light source 2R described later are triangular prisms. It is set so that the side surfaces 3b of 3 substantially coincide with each other.

Around the white light source 2, a white light source 2R,
A part of it is surrounded by a reflector plate 4 in which a reflecting mirror having focal points of 2G and 2B is formed, and an opening 4a is formed in the reflector plate 4. The reflecting mirror has a vertical cross section formed into a parabola or a spherical surface similar to a parabola.

The side surface (polishing surface) 3a of the triangular prism 3 is in contact with the opening 4a side of the reflection plate 4. Then, on the other side surface (polishing surface) 3b of the triangular prism 3,
The light guide plate 5 is arranged. In this embodiment, a semi-cylindrical condensing lens (cylindrical lens) 9 is adhered to the side surface 5a of the light guide plate 5, and the condensing lens 9 and the other side surface 3b of the triangular prism 3 are B light, G light, and Line contact is made at the R light gathering position 3e. The reason for this line contact is to prevent color mixing. For the same reason, when a point light source is used as the white light source, it is desirable to use a spherical lens as the condenser lens to make point contact at the gathering position.

A reflection plate 6 is arranged on the lower surface of the light guide plate 5, and a diffusion plate 7 is arranged on the upper surface of the light guide plate 5. A diffusion pattern for making the brightness uniform may be applied or formed on the diffusion plate 7 or the light guide plate 5.

According to the first embodiment described above, when the white light W emitted from the white light source 2B for B is emitted parallel to the aperture 4a and enters the triangular prism 3, the short wavelength component is generated by the dispersing action of the prism. The spectrum is decomposed due to the strong refraction effect. That is, the B component of the white light W is most strongly refracted from the BGR (three primary colors of light) to become the plate-shaped B light B, and reaches the collective position 3e of the prism side surface 3b. The G component becomes G light G, and the R component becomes R light R, but G
Since the light G and the R light R are unnecessary light for the white light source 2B for B, they are refracted in a direction different from the collecting position 3e of the prism side surface 3b and do not reach the collecting position 3e. Then, only the B light B of the white light W of the white light source 2B for B is condensed by the condenser lens 9 and enters the light guide plate 5. The B light B incident on the light guide plate 5 in this manner is repeatedly reflected and scattered between the reflection plate 6 and the diffusion plate 7 and is emitted to the display unit 8 side.

The white light W emitted from the white light source 2G for G is emitted in parallel through the opening 4a to form the triangular prism 3.
When the light is incident on B, the shorter wavelength component is strongly refracted by the dispersion action of the prism as in the case of the B light B described above, and is spectrally decomposed. That is, the G component of the white light W is strongly refracted second in the BGR to become the plate-shaped G light G, and reaches the collective position 3e of the prism side surface 3b. Then, the R component becomes the R light R and the B component becomes the B light B. However, since the R light R and the B light B are unnecessary lights for the G white light source 2G, they are different from the gathering position 3e of the prism side surface 3b. It refracts in different directions and does not reach the gathering position 3e. Then, only the G light G of the white light W of the G white light source 2G is condensed by the condenser lens 9 and enters the light guide plate 5. In this way, the G light G entered into the light guide plate 5 is repeatedly reflected and scattered between the reflection plate 6 and the diffusion plate 7 similarly to the B light B described above, and is emitted to the display unit 8 side. .

Further, when the white light W emitted from the R white light source 2R is emitted from the opening 4a and enters the triangular prism 3, the white light W is short due to the dispersing action of the prism as in the B light B and the G light G described above. The wavelength component is subjected to stronger refraction and is spectrally decomposed. That is, the R component of the white light W is B
The GR light is strongly refracted third and becomes plate-like R light R, and reaches the collective position 3e of the prism side surface 3b. Then, the B component becomes the B light B, and the G component becomes the G light G.
The lights B and G are unnecessary lights for the R white light source 2R, and therefore are refracted in a direction different from the collecting position 3e of the prism side surface 3b and do not reach the collecting position 3e. Then, only the R light R of the white light W of the R white light source 2R is condensed by the condenser lens 9 and enters the light guide plate 5. In this way, the R light R incident on the light guide plate 5 repeats multiple reflection and scattering between the reflection plate 6 and the diffusion plate 7 similarly to the B light B and the G light G described above, and the display unit side. Emit to.

In this way, the white light source 2 can be used to emit the R light R, the G light G, and the B light B toward the display section 8. Therefore, the R light source is turned on while the R signal is applied to the pixel, the G light source is turned on while the G signal is applied, and the B light source is turned on while the B signal is applied. By repeating the above, each frame can be configured. By changing the pitch p between the white light sources 2, the R light R, the G light G, and the B light
The color tone of each light B can be changed.

As shown in FIG. 2, the three-color backlight light source 21 according to the second embodiment constructed according to the present invention includes:
Similar to the first embodiment, a white light source 2B for B, a white light source 2G for G and a white light source 2R for R, and a triangular prism 3 which is a spectroscopic means for injecting the white light W emitted from the white light source 2 respectively. It has each. As the triangular prism 3 and the white light source 2, the same ones as in the first embodiment were used also in this embodiment.

The white light source 2 is similar to that of the first embodiment.
From the top 3c to the bottom 3d of the triangular prism 3,
The B white light source 2B, the G white light source 2G, and the R white light source 2R are arranged in this order. That is, B from the white light source,
The B white light source 2B for extracting the B light having the shortest wavelength of the G and R lights is provided near the top portion 3c, and the G white light source 2G for extracting the G light having the short wavelength is next provided for the bottom portion 3d of the B white light source 2B. The white light source 2R for R having the shortest wavelength is arranged in parallel to the bottom portion 3d of the white light source 2G for G.
The intervals between the white light sources 2B, 2G, and 2R are such that the B light of the B white light source 2B described later, the G light of the G white light source 2G described later, and the R light of the R white light source 2R described later are triangular prisms. The side surfaces 3b of 3 are set so as to coincide with each other.

The white light source 2 is surrounded by a shield plate 24 so as to prevent unnecessary light from leaking to the outside, and a slit 24a is formed in the shield plate 24 in parallel with the fluorescent tube. A plurality of the slits 24a may be arranged side by side at predetermined intervals in the optical axis direction. By doing so, it is possible to prevent unnecessary light other than the parallel light from passing through the slit 24a. Further, by disposing a collimator cylindrical lens between the slit 24a and the triangular prism 3, it is possible to use light other than the parallel light emitted from the slit. In addition, as shown in FIG. 3, the light emitting portions of the white light sources 2B, 2G, and 2R are surrounded by a reflection tape with the reflection portions inside to form a shielding plate 24. And
A slit 24a is formed by opening the light emitting portion in a slit shape.
The white light sources 2B, 2G, and 2R may be fixed by forming the slits 24a and bringing the slits 24a into contact with the triangular prism 3.
In this way, a reflective shield type cell hook may be used.

On the slit 24a side of the shielding plate 24,
The side surface (polishing surface) 3a of the triangular prism 3 is in contact. Then, the other side surface (polishing surface) 3 of the triangular prism 3
The light guide plate 5 is arranged at b. Also in this embodiment, a semi-cylindrical condensing lens (cylindrical lens) 9 is adhered to the side surface 5a of the light guide plate 5, and the condensing lens 9 and the other side surface 3b of the triangular prism 3 are B light, G light, and Line contact is made at the R light gathering position 3e.

A reflection plate 6 is arranged on the lower surface of the light guide plate 5, and a diffusion plate 7 is arranged on the upper surface of the light guide plate 5. A diffusion pattern for making the brightness uniform may be applied or formed on the diffusion plate 7 or the light guide plate 5.

According to the second embodiment described above, when the white light W emitted from the white light source 2B for B is emitted from the slit 24a and enters the triangular prism 3, the shorter wavelength component is stronger due to the dispersing action of the prism. The spectrum is decomposed by the refraction effect. That is, the B component of the white light W is most strongly refracted out of BGR (the three primary colors of light) to become the sheet-shaped B light B, and reaches the collective position 3e of the prism side surface 3b. The G component becomes G light G, and the R component becomes R light R,
Since the G light G and the R light R are unnecessary light for the B white light source 2B, they are refracted in a direction different from the collecting position 3e of the prism side surface 3b and do not reach the collecting position 3e. Then, only the B light B of the white light W of the white light source 2B for B is condensed by the condenser lens 9 and enters the light guide plate 5. The B light B incident on the light guide plate 5 in this way is reflected by the reflection plate 6.
And the diffuser plate 7 are repeatedly reflected and scattered to be emitted to the display unit 8 side.

Further, the white light W emitted from the G white light source 2G is emitted from the slit 24a, and the triangular prism 3 is produced.
When the light is incident on B, the shorter wavelength component is strongly refracted by the dispersion action of the prism as in the case of the B light B described above, and is spectrally decomposed. That is, the G component of the white light W is strongly refracted second in the BGR to become the sheet-shaped G light G, and reaches the collective position 3e of the prism side surface 3b. Then, the R component becomes the R light R and the B component becomes the B light B. However, since the R light R and the B light B are unnecessary lights for the G white light source 2G, they are different from the gathering position 3e of the prism side surface 3b. It refracts in different directions and does not reach the gathering position 3e. And G
Only the G light G of the white light W of the white light source 2G for use is condensed by the condenser lens 9 and enters the light guide plate 5. The G light G that has entered the light guide plate 5 in this way is the B light B described above.
Similarly, multiple reflection and scattering are repeated between the reflection plate 6 and the diffusion plate 7 and the light is emitted to the display unit 8 side.

Further, the white light W emitted from the R white light source 2R is emitted from the slit 2a and then the triangular prism 3 is formed.
When incident on, the short wavelength component is strongly refracted by the dispersion action of the prism, similarly to the B light B and the G light G described above, and is spectrally decomposed. That is, the R component of the white light W is strongly refracted third in the BGR to become the sheet-shaped R light R, and reaches the collective position 3e of the prism side surface 3b. Then, the B component becomes the B light B and the G component becomes the G light G. However, since the B light B and the G light G are unnecessary lights for the R white light source 2R, the gathering position 3 of the prism side surfaces 3b 3
The light is refracted in a direction different from that of e and does not reach the gathering position 3e. Then, only the R light R of the white light W of the R white light source 2R is condensed by the condenser lens 9 and enters the light guide plate 5. In this way, the R light R incident on the light guide plate 5 is
Similar to the B light B and the G light G described above, multiple reflection and scattering are repeated between the reflection plate 6 and the diffusion plate 7 and the light is emitted to the display unit side.

As shown in FIG. 4, the three-color backlight light source 31 according to the third embodiment constructed according to the present invention includes:
A white light source 2B for B, a white light source 2G for G and a white light source 2R for R are provided, and a filter section 32 which is a spectroscopic means for injecting the white light W emitted from each of the white light sources 2 is provided.

Also in the third embodiment, the white light source 2 for B is used.
As the white light source 2G for B and G and the white light source 2R for R,
The same one as in the first embodiment was used. Each white light source 2B,
A light guide portion 33 is attached to the light emission side of 2G and 2R. The light guide portion 33 includes white light sources 2B, 2G, 2R.
There is a partition wall 34 that optically separates the spaces, and the partition wall 34 forms an R light guide space r, a G light guide space g, and a B light guide space b.

One end side of the R light guide space r is continuous with the R white light source 2R, and the other end side is continuous with the R filter portion 32R which becomes R light after the white light W is transmitted. Further, one end side of the G light guide space g is continuous with the G white light source 2G, and the other end side is continuous with the G filter portion 32G that becomes G light after the white light W is transmitted. Further, one end side of the B light guide space b is continuous with the B white light source 2B, and the other end side is continuous with the B filter portion 32b that becomes B light after the white light W is transmitted. Then, in the rear of the filter unit 32, R from the R white light source 2R
Light, white light source 2 for G, G light from G and white light source 2 for B
A collective portion 35 for guiding the B light from B to the light incident portion on the side surface 5a of the light guide plate is formed. A total reflection surface is formed on the inner peripheral surface of the light guide portion 33, the surface of the partition wall 34, and the inner peripheral surface of the collecting portion 35.

According to the third embodiment described above, the white light W emitted from the R white light source 2R is repeatedly totally reflected by the reflection surface in the R light guide space r and is incident on the R filter portion 32R. To do. Then, the white light W becomes R light after passing through the R filter portion 32R, and this R light is guided by the collecting portion 35 to the light incident portion of the light guide plate side surface 5a.

Similarly, the white light W emitted from the G white light source 2G is repeatedly totally reflected by the reflecting surface in the G light guiding space g and enters the G filter portion 32G. Then, the white light W becomes G light after passing through the G filter portion 32G, and this G light is guided to the light incident portion of the light guide plate side surface 5a by the collecting portion 35.

Further, the white light W emitted from the white light source 2B for B is repeatedly totally reflected by the reflection surface in the light guiding space b for B, and then enters the B filter portion 32B. Then, the white light W becomes B light after passing through the B filter portion 32B, and this B light is guided to the light incident portion of the light guide plate side surface 5a by the collecting portion 35.

[0042]

As described above, according to the three-color backlight light source according to the first aspect, it is possible to supply the light of each of R, G, and B colors to the display section by using the white light source.
Pixels corresponding to R, G, and B colors of the color filter of the display unit are unnecessary, and a monochrome panel display can be used as the display unit. Therefore, even though the white light source is used, the pixel density can be tripled by using the device of the same standard as compared with the conventional color filter type color display device, and therefore the density of the pixel can be increased. A color image can be obtained. Further, if the pixel density is the same, the number of pixel drivers can be reduced to 1/3 as compared with the conventional color filter type color display device. Moreover, since a color filter is not used, a bright screen having a high transmittance can be obtained. Furthermore, by individually adjusting the illuminance of each white light source of the three-color backlight, it is possible to perform color balance adjustment, which was difficult with the color filter method.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a three-color backlight light source configured according to the present invention.

FIG. 2 is a configuration diagram of a second embodiment of a three-color backlight light source configured according to the present invention.

FIG. 3 is a configuration diagram of a modified example of a three-color backlight light source configured according to the present invention.

FIG. 4 is a configuration diagram of a third embodiment of a three-color backlight light source configured according to the present invention.

FIG. 5 is a configuration diagram showing a conventional color filter type color display panel.

[Explanation of symbols]

White light source for 2B B White light source for 2G G White light source for 2RR 3 Spectral means (triangular prism) 5a side 8 Display 32 Spectral means (filter section) BB light GG light RR light W white light

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-338996 (JP, A) JP-A-2-55326 (JP, A) JP-A-6-109927 (JP, A) JP-A-5- 80716 (JP, A) JP-A-61-32884 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/133 535 G02F 1/13357 F21V 8/00 601

Claims (5)

(57) [Claims] 1. A backlight for selectively supplying B, G, and R colors to a display section having a pixel region whose light transmittance changes in accordance with image information, in accordance with the image information. The three-color backlight light source includes a white light source for B, a white light source for G, and a white light source for R, and a spectroscopic unit for injecting white light emitted from each of the light sources. B light of the decomposed light of the B white light source, G light and R of the decomposed light of the G white light source
The white light source for B, the white light source for G, and the white light source for R are arranged so that R light of the decomposed light of the white light source for light enters the incident surface of the display unit.
Color backlight light source. 2. The white light emitted from each of the light sources is incident on the spectroscopic means via a parallel light incident means which is incident on the spectroscopic means as parallel light. Three-color backlight light source. 3. The three-color backlight light source according to claim 1, wherein the spectral means is a spectral prism. 4. The three-color backlight light source according to claim 1, wherein the incident surface is a side surface of the display section. 5. The three-color backlight light source according to claim 1, wherein the display unit is a monochrome panel display.