JP4655745B2 - Backlight device, manufacturing method thereof, and liquid crystal display device - Google Patents

Description

  The present invention relates to a backlight device that illuminates a liquid crystal display panel from the back, a manufacturing method thereof, and a liquid crystal display device.

  In recent years, as a display device for a television receiver, instead of a CRT (Cathode Ray Tube), a very thin type such as a liquid crystal display (LCD) or a plasma display (PDP) is used. Display devices have been proposed and put into practical use. In particular, liquid crystal display devices that use liquid crystal display panels can be driven with low power consumption, and the spread of the large liquid crystal display panels has been reduced, leading to technical research and development. ing.

In such a liquid crystal display device, a backlight system in which a color image is displayed by illuminating a transmissive liquid crystal display panel including a color filter with a backlight device that illuminates the surface from the back side becomes the mainstream. ing.
As a light source of the backlight device, a cold cathode fluorescent tube (CCFL) that emits white light using a fluorescent tube and a light emitting diode (LED) are promising.
In particular, with the development of blue light emitting diodes, light emitting diodes that emit the three primary colors of light, red light, green light, and blue light, have been prepared. By mixing light, white light with high color purity can be obtained. Therefore, by using this light emitting diode as the light source of the backlight device, the color purity through the liquid crystal display panel is increased, so that the color reproduction range can be greatly expanded compared with the CCFL. Furthermore, the brightness of the backlight device can be significantly improved by using a high-power light emitting diode (LED) chip.

  Using such LEDs, for example, a direct type, that is, a backlight device in which the LEDs are arranged directly under the light emitting surface of the device has been proposed (see, for example, Non-Patent Document 1).

Nikkei Electronics (Nikkei BP), December 20, 2004 (No. 889), pages 123-130

By the way, it is important to uniformly illuminate the liquid crystal display panel particularly in the backlight device used in the liquid crystal display device as described above. However, it is difficult to uniformly illuminate the entire surface, and an image of the light source itself may be seen.
In a backlight device using a fluorescent tube as a light source, a technique is adopted in which patterns such as dots having different densities are formed on a diffusion plate by printing or the like to suppress such luminance unevenness.
However, in the backlight device using the LED as described above, there is a variation in the characteristics of the single LED, and a variation in luminance between the LEDs cannot be ignored. For this reason, there is a problem that it is still difficult to completely remove luminance unevenness and color unevenness when a pattern such as dots provided on the diffusion plate is uniformly selected over the entire light exit surface.

  In view of the above problems, an object of the present invention is to provide a backlight device, a manufacturing method thereof, and a liquid crystal display device capable of suppressing luminance unevenness and color unevenness due to variations in light sources such as LEDs. And

In order to solve the above problems, a backlight device according to the present invention includes a light source and a light-transmitting substrate that is disposed to face the light source and has a diffusing material attached to a surface that faces the light source . The diffusing material has a configuration in which the density of the portion with high irradiation energy of light emitted from the light source is high and the density of the portion with low irradiation energy is low and attached to the light-transmitting substrate .

Furthermore, the manufacturing method of the backlight device of the present invention includes a step of applying a photosensitive material containing a diffusing material on a light-transmitting substrate , and finally facing the photosensitive material of the light-transmitting substrate. A step of arranging a light source incorporated in the backlight device or a light source having the same irradiation energy distribution as the light source, a step of irradiating the photosensitive material with light from the light source, and a step of developing the photosensitive material. It is characterized by having.
Furthermore, the present invention provides a liquid crystal display device comprising a transmissive liquid crystal display panel and a backlight device that illuminates the liquid crystal display panel from the back side. The backlight device has the above-described configuration of the present invention. The backlight device is used .

As described above, in the present invention, the light-transmitting substrate is disposed so as to face the light source, and the amount of light emitted from the light source such as an LED and reaching the light-transmitting substrate is measured on the surface facing the light source. The diffusion material is attached with a distribution corresponding to the distribution.
That is, this diffusing material is configured to adhere with a distribution with a high or low density corresponding to the level of irradiation energy of light emitted from the light source, for example.

Such a distribution of the diffusing material can be easily formed by, for example, the manufacturing method of the backlight device according to the present invention.
That is, a photosensitive material containing a diffusing material is coated on a light transmissive substrate, and a light source that is actually incorporated in a backlight device is disposed opposite to the light transmissive substrate coated with the photosensitive material. Then, by actually irradiating the photosensitive material with light emitted from the light source and developing it, the diffusing material can be distributed corresponding to the luminance distribution of each light source.
According to the backlight device and the liquid crystal display device of the present invention configured as described above, the diffusing material is distributed on the light-transmitting substrate in accordance with the luminance variation due to the characteristics of the light source itself. When diffusing light in the part where the irradiation energy of the emitted light from the light is high and transmitting it with low light diffusion in the part where the irradiation energy is low, it is possible to provide a conventional uniform dot pattern structure Compared to the above, it is possible to suppress the luminance unevenness and the color unevenness with higher accuracy.

As described above, according to the present invention, in the backlight device and the liquid crystal display device, it is possible to suppress luminance unevenness and color unevenness caused by variations in the light source itself.
Moreover, according to the method for manufacturing a backlight device of the present invention, it is possible to easily manufacture a backlight device that can improve luminance unevenness and color unevenness due to variations in light sources.

Examples of the best mode for carrying out the present invention will be described below, but the present invention is not limited to the following examples.
The present invention can be applied to, for example, a transmissive color liquid crystal display device 100 configured as shown in FIG. The transmissive color liquid crystal display device 100 includes a transmissive color liquid crystal display panel 110 and a backlight device 140 provided on the back side of the color liquid crystal display panel 110. Although not shown, the transmissive color liquid crystal display device 100 includes a receiving unit such as an analog tuner and a digital tuner that receives terrestrial and satellite waves, and a video signal that processes a video signal and an audio signal received by the receiving unit, respectively. An audio signal output unit such as a processing unit, an audio signal processing unit, a speaker that outputs an audio signal processed by the audio signal processing unit, and the like may be provided.

  In the transmissive color liquid crystal display panel 110, two transparent substrates (TFT substrate 111 and counter electrode substrate 112) made of glass or the like are arranged to face each other, and, for example, twisted nematic (TN) liquid crystal is provided in the gap. The liquid crystal layer 113 encapsulating the liquid crystal layer 113 is provided. On the TFT substrate 111, signal lines 114 arranged in a matrix, scanning lines 115, thin film transistors 116 serving as switching elements arranged at intersections of the signal lines 114 and the scanning lines 115, and pixel electrodes 117 are formed. Has been. The thin film transistor 116 is sequentially selected by the scanning line 115 and writes the video signal supplied from the signal line 114 to the corresponding pixel electrode 117. On the other hand, a counter electrode 118 and a color filter 119 are formed on the inner surface of the counter electrode substrate 112.

  The color filter 119 is divided into a plurality of segments corresponding to each pixel. For example, as shown in FIG. 2, it is divided into three segments of a red filter CFR, a green filter CFG, and a blue filter CFB which are three primary colors. The arrangement pattern of the color filter 119 includes a delta arrangement and a square arrangement, although not shown, in addition to the stripe arrangement shown in FIG.

The configuration of the transmissive color liquid crystal display device 100 will be described again with reference to FIG. In the transmissive color liquid crystal display device 100, the transmissive color liquid crystal display panel 110 having such a configuration is sandwiched between two polarizing plates 131 and 132, and white light is irradiated from the back side by the backlight device 140. By driving with an active matrix system, a desired full-color image can be displayed.
The backlight device 140 illuminates the color liquid crystal display panel 110 from the back side. As shown in FIG. 1, the backlight device 140 includes a diffusion plate 141, a light source (not shown), and a backlight plate 120 in order to mix light emitted from the light source into white light. The configuration includes an optical function sheet group 145 such as a diffusion sheet 142, a prism sheet 143, and a polarization conversion sheet 144 that are arranged on the diffusion plate 141.
The diffusing plate 141 makes the luminance emitted from the surface emission uniform by internally diffusing the light emitted from the backlight casing 120.
In general, the optical function sheet group has, for example, a function of decomposing incident light into orthogonal polarization components, a function of compensating for a phase difference of light waves to achieve a wide-angle viewing angle and preventing coloring, a function of diffusing incident light, and a brightness improvement And is provided to convert the light emitted from the backlight device 140 into illumination light having optical characteristics optimal for illumination of the color liquid crystal display panel 110. . Therefore, the configuration of the optical function sheet group 145 is not limited to the diffusion sheet 142, the prism sheet 143, and the polarization conversion sheet 144 described above, and various optical function sheets can be used.

FIG. 3 shows a schematic configuration diagram in the backlight housing 120. As shown in FIG. 3, in this backlight device, a light emitting diode may be used as a light source, and although not shown, a CCFL or the like can also be used. In the illustrated example, the backlight casing 120 uses a red light emitting diode 21R that emits red light, a green light emitting diode 21G that emits green light, and a blue light emitting diode 21B that emits blue light as light sources. . For example, the peak wavelengths of red light emitted from the red light emitting diode 21R, green light emitted from the green light emitting diode 21G, and blue light emitted from the blue light emitting diode 21B are about 640 nm, 530 nm, and 450 nm, respectively. The peak wavelengths of red light and blue light emitted by the red light emitting diode 21R and the blue light emitting diode 21B may be shifted from 640 nm to the long wavelength side and from 450 nm to the short wavelength side, respectively. In this way, when the peak wavelength is shifted to the long wavelength side and the short wavelength side, the color gamut can be expanded, so that the color reproduction range of the image displayed on the color liquid crystal display panel can be expanded.
In the following description, when the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B are collectively referred to, they are simply referred to as the light emitting diode 21.

The light emitting diode 21 is a side having a lens function that mainly emits light in the lateral direction, such as the lens-shaped LED chip described in the above-mentioned Patent Document 1, or the LED chip having other lens-shaped radiation directivity characteristics. An emitting type may be used, or a light emitting diode having radiation directivity characteristics in the upward direction rather than in the lateral direction may be used.
As shown in FIG. 3, the light emitting diode unit 21n (n is a natural number) is formed by arranging a plurality of the light emitting diodes 21 in a desired order on the substrate 22 as shown in FIG.
In order to form the light emitting diode unit 21n, the order in which the light emitting diodes 21 are arranged on the substrate 22 is the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B as shown in FIG. Although the basic arrangement method and not shown, for example, the green light emitting diodes 21G are arranged at equal intervals, and the red light emitting diodes 21R and the blue light emitting diodes 21B are alternately arranged between the adjacent green light emitting diodes 21G. There are various ways of arrangement such as the order.
As shown in FIG. 3, the arrangement of the light emitting diode units 21n in the backlight housing 120 may be arranged so that the longitudinal direction of the light emitting diode units 21n is in the horizontal direction, not shown. However, the light emitting diode units 21n may be arranged so that the longitudinal direction thereof is the vertical direction, or the two may be combined.
The method of arranging the light emitting diode units 21n so that the longitudinal direction is the horizontal direction or the vertical direction is the same as the CCFL arrangement method used as the light source of the conventional backlight device. The designed know-how can be used, and the cost can be reduced and the time required for manufacturing can be shortened.
The inner wall surface 120a of the backlight housing 120 is a reflective surface that is subjected to reflection processing in order to increase the utilization efficiency of the light emitted from the light emitting diode 21.

FIG. 4 is a partial cross-sectional view taken along the line XX attached to the transmissive color liquid crystal display device 100 shown in FIG. 1 when the transmissive color liquid crystal display device 100 is assembled. As shown in FIG. 4, the color liquid crystal display panel 110 constituting the liquid crystal display device 100 includes spacers 103 a and 103 b formed by an external frame 101 that is an external housing of the transmissive color liquid crystal display device 100 and an internal frame 102. It is hold | maintained so that it may pinch | interpose through. A guide member 104 is provided between the outer frame 101 and the inner frame 102, and the color liquid crystal display panel 110 sandwiched between the outer frame 101 and the inner frame 102 is displaced in the longitudinal direction. Is suppressed.
On the other hand, the backlight device 140 constituting the transmissive color liquid crystal display device 100 includes the diffusion plate 141 on which the optical function sheet group 145 is laminated as described above. In addition, a reflection sheet 126 is disposed between the diffusion plate 141 and the backlight casing 120.
The reflection sheet 126 is disposed so that the reflection surface thereof faces the light incident surface 141 a of the diffusion plate 141 and is closer to the backlight housing 120 than the light emitting direction of the light emitting diode 21. As the reflection sheet 126, for example, a silver-enhanced reflection film formed by sequentially laminating a silver reflection film, a low refractive index film, and a high refractive index film on a sheet base material can be used. Further, the reflection sheet 126 is mainly emitted from the light emitting diode 21 and radiated downward due to the radiation angle distribution thereof, or the inner wall surface 120a which has been subjected to the reflection processing of the backlight casing 120 to be a reflection surface. The reflected light is reflected.
The diffusion plate 141 is held by a bracket member 108 provided in the backlight housing 120.

In the backlight device of the present invention, as shown in FIG. 4, a light transmissive substrate 30 is disposed between the light diffusing plate 141 so as to face the light source, that is, the light emitting diode 21 in this case. A diffusing material 32 having a distribution corresponding to the distribution of the amount of light emitted from the light emitting diode 21 and reaching the light transmitting base 30 is provided on the surface of the base 30 facing the light source, that is, the light emitting diode 21. It is set as the structure comprised by adhering to.
The light transmissive substrate 30 can also be used as the diffusion plate 141. That is, the light transmissive substrate 30 is emitted from the light emitting diode 21 to the inner side surface 141a of the diffusion plate 141 facing the light emitting diode 21. It is also possible to adopt a configuration in which the diffusing material 32 is attached with a distribution corresponding to the distribution of the amount of light reaching the light source.

  The transmissive color liquid crystal display device 100 having such a configuration is driven by a drive circuit 200 as shown in FIG. 5, for example. The driving circuit 200 includes a color liquid crystal display panel 110, a power source 210 that supplies driving power for the backlight device 140, an X driver circuit 220 and a Y driver circuit 230 that drive the color liquid crystal display panel 110, and video signals supplied from the outside. Or an RGB process processing unit 250 that receives a video signal received by a receiving unit (not shown) included in the transmissive color liquid crystal display device 100 and processed by the video signal processing unit, via an input terminal 240, and the RGB process. An image memory 260 and a control unit 270 connected to the processing unit 250, a backlight drive control unit 280 for driving and controlling the backlight device 140, and the like are provided.

In the drive circuit 200, the video signal input through the input terminal 240 is subjected to signal processing such as chroma processing by the RGB process processing unit 250, and is further suitable for driving the color liquid crystal display panel 110 from the composite signal. It is converted into an RGB separate signal and supplied to the control unit 270 and also supplied to the X driver 220 via the image memory 260.
Further, the control unit 270 controls the X driver circuit 220 and the Y driver circuit 230 at a predetermined timing according to the RGB separate signal, and supplies the X driver circuit 220 together with the video signal from the image memory 260. By driving the color liquid crystal display panel 110 with the RGB separate signal, an image corresponding to the RGB separate signal is displayed.

The backlight drive control unit 280 generates a pulse width modulation (PWM) signal from the voltage supplied from the power supply 210 and drives each light emitting diode 21 that is a light source of the backlight device 140. In general, the color temperature of a light emitting diode has a characteristic that it depends on an operating current. Therefore, in order to reproduce the color faithfully (with a constant color temperature) while obtaining a desired luminance, it is necessary to drive the light emitting diode 21 using a pulse width modulation signal to suppress the color change.
The user interface 300 selects a channel to be received by a receiving unit (not shown) described above, adjusts an audio output amount to be output by an audio output unit (not shown), or from a backlight device 140 that illuminates the color liquid crystal display panel 110. This is an interface for executing white light brightness adjustment, white balance adjustment, and the like.
For example, when the user adjusts the brightness from the user interface 300, the brightness control signal is transmitted to the backlight drive control unit 280 via the control unit 270 of the drive circuit 200. In response to the luminance control signal, the backlight drive control unit 280 changes the duty ratio of the pulse width modulation signal for each of the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B to change the red light emitting diode 21R, green The light emitting diode 21G and the blue light emitting diode 21B are driven and controlled.

Next, in the backlight device and the liquid crystal display device of the present invention, the schematic configuration of each example of the light-transmitting substrate (or diffusion plate) in which the diffusing material is distributed will be described.
FIG. 6 is a schematic cross-sectional configuration diagram of a main part of an embodiment of the backlight device of the present invention. In this example, a photosensitive material 31 containing a diffusing material 32 is applied to the light source of the light transmissive substrate 30, that is, the surface facing the light emitting diode 21 in this case, and irradiation of light emitted from the light emitting diode 21 is performed. In the region where the energy is relatively high as indicated by an arrow L0, the density of the diffusing material 32 is high. Similarly, in the region where the irradiation energy of light emitted from the light emitting diode 21 is relatively low as indicated by the arrow L1, the diffusing material is used. The case where it is set as the distribution from which the density of 32 becomes low is shown. Further, in a region where the irradiation energy is very low as indicated by an arrow L2, for example, the diffusing material 32 may not be attached as in the illustrated example.
Such a distribution of the diffusing material 32 can be easily obtained by using, as the photosensitive material 31, for example, a material that cures at a portion where the intensity of irradiation energy is high and hard at a low portion, and at least a portion falls off. Can do.
In addition, the light emitting diode 21 which is a light source is made to emit light in a state where the light emitting diode 21 is incorporated and fixed in an actually incorporated backlight housing, and the photosensitive material 31 is exposed, for example. At this time, the light emitted from the light source is reflected not only by the light directly incident on the light-transmitting substrate 30, but also by another light source, or the inner side surface 120a having the reflection structure described in FIG. The light is reflected by the sheet 126 or the like and reaches the light transmissive substrate 30.
Then, by performing development processing thereafter, it is possible to obtain the light transmissive substrate 30 having the distribution of the diffusing material 32 having the configuration shown in FIG.
By incorporating the light-transmitting substrate having such a configuration into the backlight device that sets the light source that has been irradiated, the luminance distribution of the light source that is actually used, that is, the luminance variation due to, for example, the characteristics of the light source itself, can be reduced. The diffusion material will be attached with a corresponding distribution.

Further, as shown in FIG. 7, the density of the diffusing material 32 is low in the region where the irradiation energy of the light emitted from the light emitting diode 21 as the light source is relatively high as indicated by an arrow L0. Alternatively, a distribution in which the density of the diffusing material 32 increases in a region where the irradiation energy of light emitted from the light emitting diode 21 is relatively low as indicated by an arrow L1 may be adopted.
Such a distribution of the diffusing material 32 can be easily obtained by using, as the photosensitive material 31, for example, a material that is hard to be cured at a portion where the intensity of irradiation energy is high and at least a portion is dropped and is cured at a low portion. it can.

In each of these examples, a diffusing plate can be used as the light transmissive substrate 30.
In addition, the material selected from acrylic, polycarbonate, polyolefin, etc. is preferable as the material of the light transmissive substrate 30 and the diffuser plate when the diffuser plate is used instead of the light transmissive substrate 30.
Further, as the diffusing material 32, one or several kinds are selected from acrylic, styrene, silica and the like, and added to the photosensitive material 32 for use.

The transmission and scattering modes of light from the light source in the case of such a configuration will be described.
FIG. 8 is a schematic cross-sectional configuration diagram in the case where the diffusion material 32 having the distribution described in FIG. 6 is attached to the inner surface 141a of the diffusion plate 141 facing the light emitting diode 21 as an example.
In this case, the portion irradiated with the light L0 having a high irradiation energy among the light emitted from the light emitting diode 21 has a relatively high density of the diffusing material 32, and has a stronger diffusion characteristic. Therefore, the light beam is indicated by an arrow Ld0. Are scattered and emitted at various angles. On the other hand, since the diffusion material 32 has a relatively low density and has a weak diffusion characteristic, the portion where the irradiation energy is weak transmits relatively as shown in the arrow Ld1, without being relatively scattered, It is taken out. For this reason, the luminance unevenness of the light emitted from the diffusion plate 141 is reduced.

On the other hand, in the example shown in FIG. 9, a light-transmitting substrate 30 is provided between the light-emitting diode 21 that is a light source and the diffusion plate 141, and the diffusion material having the distribution described in FIG. It is a general | schematic cross-section block diagram at the time of attaching 32.
In this example, it is desirable that a half mirror made of a laminated structure of dielectric thin films or the like is provided on the surface of the light transmissive substrate 30 to which the diffusing material 32 adheres.
As described above, when the half mirror is formed on the inner surface of the light transmissive substrate 30, the diffusion material 32 irradiates the portion of the light emitted from the light emitting diode 21 that is the light source that is irradiated with the light L 0 with high irradiation energy. Since the light is incident on a portion having a relatively low density and a relatively low scattering, the light is reflected while maintaining the incident angle substantially. In addition, light having a relatively low irradiation energy indicated by the arrow L1 is extracted upward by a lens effect due to strong scattering at a portion where the diffusion material 32 has a relatively high density. As a result, it is possible to reduce luminance unevenness.

Next, each example of the manufacturing method of the backlight apparatus of this invention is demonstrated.
10A to 10C show manufacturing process diagrams of an embodiment of a method for manufacturing a backlight device according to the present invention.
In this case, as shown in FIG. 10A, a photosensitive material 31 containing a diffusing material 32 at a predetermined density (not shown) is applied on the light-transmitting substrate 30 with a substantially uniform thickness.
Next, as shown in FIG. 10B, a light source, that is, for example, a light emitting diode 21 is disposed facing the photosensitive material 31 of the light-transmitting substrate 30, and light emitted from the light emitting diode 21 is applied to the photosensitive material 31. Irradiate to perform exposure. At this time, assuming that the irradiation energy of the light emitted from the light emitting diode 21 has a distribution indicated by a solid line I in FIG. 10B, for example, as the photosensitive material 31, a region where the irradiation energy is a certain level or more is cured after development, In the case of using a material that drops off after development, when this photosensitive material 31 is developed, as shown in FIG. 10C, the density of the diffusion material 32 in the portion with relatively high irradiation energy is high and the diffusion material in the portion with low irradiation energy. The diffusing material 32 can be distributed so that the density of 32 is low.

11A to 11C show the case where a material that cures a region having a relatively low irradiation energy is used as the photosensitive material.
That is, for example, as shown in FIG. 11A, a photosensitive material 31 containing a diffusion material 32 (not shown) having a predetermined density is applied on the light-transmitting substrate 30 with a substantially uniform thickness.
Next, as shown in FIG. 11B, a light source, that is, for example, a light emitting diode 21 is disposed facing the photosensitive material 31 of the light-transmitting substrate 30, and light emitted from the light emitting diode 21 is applied to the photosensitive material 31. Irradiate to perform exposure. At this time, assuming that the irradiation energy of the light emitted from the light emitting diode 21 has a distribution indicated by a solid line I in FIG. 11B, for example, as the photosensitive material 31, the irradiation energy drops off after development in a region where the irradiation energy is a certain level or more. In the case of using a material that is cured after development, when the photosensitive material 31 is developed, as shown in FIG. 11C, the density of the diffusion material 32 in the portion with relatively high irradiation energy is low, and the diffusion material in the portion with low irradiation energy. The diffusing material 32 can be distributed so that the density of 32 is high.

Further, FIGS. 12A to 12D show a case where a resist is used in order to obtain a configuration in which the density of the diffusing material is lowered in a portion where the irradiation energy of light from the light source is strong.
In this case, as shown in FIG. 12A, a resist 33 is applied on the light-transmitting substrate 30 with a substantially uniform thickness.
Thereafter, as shown in FIG. 12B, a light source, for example, a light emitting diode 21 is disposed opposite to the resist 33 coated on the light transmissive substrate 30, and light emitted from the light emitting diode 21 is irradiated onto the resist 33. Exposure. At this time, if the irradiation energy of the light emitted from the light emitting diode 21 has a distribution indicated by a solid line I in FIG. 12B, the resist 33 remains after development in a region where the irradiation energy is a certain level or more and falls off after development in a region where the irradiation energy is less than a certain level. When the material to be used is used, after development, as shown in FIG. 12C, the resist 33 with a relatively high irradiation energy remains and the resist 33 with a low irradiation energy is removed.
Thereafter, a photosensitive material 31 to which a diffusing material 32 is added with a predetermined density is applied on the resist 33 patterned in this way, and then the upper surface of the remaining resist 33 indicated by a broken line S, for example, is applied. The photosensitive material 31 is squeezed so as to have a substantially uniform thickness in the plane along the surface. Thereafter, the photosensitive material 31 is uniformly cured and the remaining resist 33 is removed, so that the density of the diffusion material 32 in the portion with relatively high irradiation energy is low and the diffusion material 32 in the portion with low irradiation energy. The diffusing material 32 can be distributed so as to have a high density distribution.

According to the manufacturing method of the present invention described above, the light-transmitting substrate to which the diffusing material having the target distribution is attached is easily formed in a relatively simple manufacturing process corresponding to the light source of the backlight device. Therefore, the backlight device having the configuration of the present invention can be easily manufactured.
The size of the diffusing material 32 can be appropriately selected according to the intended intensity of scattering, and two or more types of diffusing materials 32 of materials may be used.
Examples of the photosensitive material 31 include a water-soluble photosensitive resin such as polyvinyl alcohol / stilbazolium, a photocrosslinkable photosensitive resin such as cinnamic acid, a light dispersion crosslinkable photosensitive resin such as bisazide, and O-quinone diad. An oil-soluble photosensitive resin such as a photodegradable polarity-changing photosensitive resin such as a system can be used (see, for example, JP-A-60-129739).

When the photosensitive material is a material that is sensitive to ultraviolet light, for example, by emitting light of the light source incorporated in a backlight device, leave a distribution of light quantity at the position to place the light-transmissive substrate was previously measured, whereas, for example, ultraviolet Light sources (for example, LEDs) that emit light are arranged in a matrix, and for example, the ultraviolet light emitting LEDs are caused to emit light with a distribution that is substantially the same as the distribution of the amount of light from the light source incorporated in the backlight device described above, and exposure and development are performed. By doing so, it is possible to distribute the diffusing material with a pattern corresponding to the light of the light source incorporated in the backlight device.
When leaving a portion where the amount of light reaching the photosensitive material is high or not, after measuring the above-mentioned light amount distribution, when the result is reflected in, for example, the signal intensity and output to the ultraviolet light emitting LEDs arranged in a matrix In addition, by reversing the data, it is also possible to reverse the place to be removed and the place to be removed.

  As described above, even in the case where the photosensitive material is exposed by emitting a separate light source with a distribution corresponding to the distribution of the amount of emitted light instead of the light source actually used, It is possible to form the light source used for the light source, that is, the distribution corresponding to the variation in the brightness due to, for example, the characteristics of the light source itself, with a good diffusion material.

  As described above, in the backlight device and the liquid crystal display device of the present invention, a light source of a backlight device that is actually incorporated by applying a photosensitive material containing a diffusion material to a diffusion plate or a light-transmitting substrate, or Luminance of the brightness of a light source such as a light emitting diode or a fluorescent tube is obtained by emitting light from a photosensitive light source with a distribution corresponding to the distribution of light emitted from the light source, irradiating the light to sensitize and develop the photosensitive material The diffusion material can be provided with a distribution corresponding to the strength. Then, by scattering or transmitting light corresponding to the distribution of the diffusing material, it becomes possible to reduce luminance unevenness and color unevenness due to variations in luminance of the light source itself, and to have more uniform luminance. A backlight device and a liquid crystal display device which can be illuminated or displayed and have excellent characteristics can be provided.

Note that the present invention is not limited to the examples described above, and it is possible to use light sources such as light-emitting diodes and other fluorescent tubes having various configurations as light sources, and for backlight devices and liquid crystal display devices. It goes without saying that various modifications and changes can be made in other configurations without departing from the configuration of the present invention.

1 is a schematic exploded perspective view of an embodiment of a liquid crystal display device according to the present invention. It is a schematic plane block diagram of the principal part of one Embodiment of the liquid crystal display device by this invention. 1 is a schematic perspective configuration diagram of a main part of an embodiment of a backlight device according to the present invention. 1 is a schematic cross-sectional configuration diagram of an embodiment of a liquid crystal display device according to the present invention. 1 is a schematic block configuration diagram of an embodiment of a drive circuit for driving a liquid crystal display device according to the present invention. It is a schematic sectional block diagram of the principal part of one Example of the backlight apparatus by this invention. It is a schematic sectional block diagram of the principal part of one Example of the backlight apparatus by this invention. It is a schematic sectional block diagram of the principal part of one Example of the backlight apparatus by this invention. It is a schematic sectional block diagram of the principal part of one Example of the backlight apparatus by this invention. FIG. 4A is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 7B is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 6C is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 4A is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 7B is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 6C is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 4A is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 7B is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 6C is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention. FIG. 4D is a manufacturing process diagram of an embodiment of a method for manufacturing a backlight device according to the present invention.

Explanation of symbols

  21. Light-emitting diode, 30. Light transmissive substrate, 31. Photosensitive material, 32. Diffusion material, 33. Resist, 21. Light emitting diode, 21R. Red light emitting diode, 21G. Green light emitting diode, 21B. Blue light emitting diode, 100. Liquid crystal display device, 110. Color liquid crystal display panel, 120. Backlight casing, 126. Reflection sheet, 140. Backlight device, 141. Diffusion plate

Claims (7)

A light source ;
A light-transmitting substrate that is disposed to face the light source and has a diffusing material attached to a surface that faces the light source ;
The diffusing material is attached to the light-transmitting substrate with a high density in a portion with high irradiation energy of light emitted from the light source and a low density in a portion with low irradiation energy.
Backlights apparatus. The light-transmitting substrate diffuser and has been formed Ru請 Motomeko 1 backlight device according. The diffusion material, the backlight device according to 請 Motomeko 1 or 2 is added Ru formed on the photosensitive material. The light source is a backlight device according to any one of 請 Motomeko 1-3 Ru formed is a light emitting diode. A method of manufacturing a backlight device,
Applying a photosensitive material containing a diffusing material onto a light- transmitting substrate;
A step of disposing a light source that is finally incorporated into the backlight device, or a light source having the same irradiation energy distribution as the light source, facing the photosensitive material of the light-transmitting substrate;
Irradiating the photosensitive material with light from the light source;
That having a, a step of developing the photosensitive material
Method of manufacturing a backlighting system. 6. The method according to claim 5, wherein the photosensitive material is a material that cures after development in a region where the irradiation energy is a certain level or more and falls off after development in a region less than a certain level. Transmission type liquid crystal display panel, Ri formed and a backlight device for illuminating the liquid crystal display panel from the back side,
The backlight equipment comprises a light source, it is arranged to face the light source, the light source and the surface facing the light transmissive substrate formed by attaching the diffusion member, and
The diffusing material is attached to the light-transmitting substrate with a high density in a portion with high irradiation energy of light emitted from the light source and a low density in a portion with low irradiation energy.
Liquid crystal display device.

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