JP3534170B2 - Reflective liquid crystal display device with touch panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention integrates a resistive film type touch panel with a reflective liquid crystal display device to which an auxiliary lighting device is added.

[0002]

2. Description of the Related Art A liquid crystal display device is a CRT (Cathode).
Ray Tube), PDP (Plasma Dis)
play Panel), EL (Electro Lu
Unlike other display devices such as a luminescent device, the liquid crystal itself does not emit light, and characters and images are displayed by adjusting the amount of light transmitted from a specific light source.

Liquid crystal display devices can be roughly classified into transmissive liquid crystal display devices and reflective liquid crystal display devices. A transmissive liquid crystal display device has a light source (backlight) on the back surface of the liquid crystal cell.
A surface emitting source such as a fluorescent tube or EL is arranged. On the other hand, the reflective liquid crystal display device has an advantage that it does not need a backlight and consumes less power because it uses ambient light to perform display. Further, in a very bright place such as exposed to direct sunlight, the transmissive liquid crystal display device has a reduced visibility, whereas the reflective liquid crystal display device has an advantage that it can be seen more clearly. is doing. For this reason,
The reflective liquid crystal display device is applied to a portable information terminal and a mobile computer, which are in increasing demand in recent years.

Further, as an information input device used in a portable information terminal or a mobile computer, a resistive film type touch panel arranged on the front surface of a liquid crystal display section is often used. The resistance film type touch panel is low in cost and easy to assemble on the front surface of the display unit.

However, the reflective liquid crystal display device has the following problems. Since the reflective liquid crystal display device uses ambient light for display, the display brightness is highly dependent on the surrounding environment, and the display cannot be recognized in darkness such as at night. In particular, in a reflective liquid crystal display device using a color filter for colorization or a reflective liquid crystal display device using a polarizing plate, the above problems are very large, and when sufficient ambient light cannot be obtained, , An auxiliary lighting device is required.

Further, since the reflection type liquid crystal display device has the reflection plate on the back surface, the backlight used in the transmission type liquid crystal display device cannot be used. Therefore, a semi-transmissive liquid crystal display device using a half mirror as a reflection plate has been proposed, but its display quality is not necessarily good.

Therefore, there has been proposed a method of illuminating the reflection type liquid crystal display device from the front side as an auxiliary lighting means when the surroundings are dark. Conventionally, liquid crystal display devices having such auxiliary illumination means have been proposed in JP-A-6-324332 and JP-A-9-212148.

In Japanese Patent Laid-Open No. 6-324332, a light guide is arranged on the entire rear surface of a reflective liquid crystal display device, and light is emitted from the light guide. Japanese Patent Application Laid-Open No. 9-212148 describes various embodiments in which a movable illumination unit is provided in front of the display unit and storage capability is taken into consideration so that sufficient display can be recognized even in a dark place. There is.

[0009]

However, the above-mentioned conventional techniques have various problems. JP-A-6-
In Japanese Patent No. 324332, an auxiliary lighting device is arranged behind the reflective liquid crystal display device. Further, if the resistive film type touch panel as the input detection device is provided, the thickness of the two mechanisms of the auxiliary lighting device and the input detection device is added, and the portability is significantly impaired.

In Japanese Patent Laid-Open No. 9-211448, an auxiliary lighting device is arranged in front of the reflective liquid crystal display device. In addition, if a resistive film type touch panel that is an input detection device is provided, it is possible to use an auxiliary lighting device and an input detection device.
The thickness of two mechanisms is added, and portability is significantly impaired.

As shown in FIG. 9, a reflection type liquid crystal display device 4 is provided.
3, auxiliary lighting device 42, and resistive touch panel 4
When 1 is present separately, in a bright place, the auxiliary lighting device 4
Since the second light source 48 is not turned on, the external light 47 that has passed through the resistive film type touch panel 41 is reflected by the surface of the light guide 44, and the light reaching the surface of the reflective liquid crystal display device 43 is attenuated and reflected. The contrast of the display screen of the liquid crystal display device 43 is lowered. That is, it is necessary to reduce the number of components on the reflective liquid crystal display device 43 as much as possible.

Further, since the auxiliary lighting device of the reflective liquid crystal display device and the resistive film type touch panel are separately provided,
Increasing weight is unavoidable.

Further, since the auxiliary lighting device of the reflective liquid crystal display device and the resistive film type touch panel are separately provided,
The assembly work and the unit price of the parts will also increase.

In portable electronic equipment, a technology for designing compact and lightweight is particularly important, and for this reason, it is necessary to study reduction in size and weight of the entire equipment that constitutes the equipment.

That is, in the reflective liquid crystal display device,
If the resistive film type touch panel and the auxiliary lighting device are used at the same time, the device becomes large and costly, and the weight becomes heavy.

According to the present invention, in a reflective liquid crystal display device equipped with a touch panel, a resistive film type touch panel located in front of the reflective liquid crystal display device and an auxiliary lighting device are integrated.

[0017]

According to the present invention, a resistive touch panel is arranged on a display portion of a reflective liquid crystal display device, and auxiliary illumination is provided on an end face of a transparent substrate which constitutes a lower portion of the resistive touch panel. The device is arranged, and the transparent substrate is
Using as a light guide of the auxiliary lighting device, the light emitted from the auxiliary lighting device, so as to be emitted to the display unit of the reflective liquid crystal display device arranged below the resistive film type touch panel, A reflective liquid crystal display device provided with a touch panel, characterized in that spacers each having a sparse and dense dot pattern corresponding to a distance from the auxiliary lighting device are provided on a lower electrode of the resistive film type touch panel. .

According to the present invention, the resistive film type touch panel is arranged on the display portion of the reflective liquid crystal display device, and the auxiliary illuminating device is arranged on the end face of the transparent substrate constituting the lower part of the resistive film type touch panel. By using this auxiliary lighting device, the display of the reflective liquid crystal display device can be viewed even if the surroundings are darkened and the amount of external light is reduced, making it difficult to see the display. By using the transparent substrate that constitutes the lower portion of the resistive film type touch panel as a light guide for the auxiliary lighting device, the number of components above the reflective liquid crystal display device is reduced and the attenuation of external light can be reduced. That is, when the display is performed by using external light without using the auxiliary lighting device, it is possible to suppress the attenuation of the external light that has been conventionally caused by the surface reflection on the light guide of the auxiliary lighting device that is separately provided. The display quality and contrast of the reflective liquid crystal display device are not deteriorated.

In addition, on the lower electrode of the resistive film type touch panel, a sparse and dense dot pattern corresponding to the distance from the auxiliary lighting device, for example, a dot pattern that changes from sparse to dense as it goes away from the light source of the auxiliary lighting device. Provide a spacer consisting of. As a result, the light emitted from the auxiliary lighting device can be uniformly emitted to the display section of the reflective liquid crystal display device arranged below the resistive film type touch panel, and the light from the auxiliary lighting device can be effectively used. Can be used for.

The present invention is also characterized in that the spacer is made of a transparent member. According to the invention, by forming the spacer with a transparent member, it is possible to prevent the shadow of the spacer and the spacer itself from being visually recognized in a dot shape, and improve the display quality of the reflective liquid crystal display device.

According to the present invention, a reflective sheet is provided on the end surface of the transparent substrate facing the end surface on which the auxiliary lighting device is arranged, and the spacer is sparsely arranged from the end surface of the auxiliary lighting device toward the end surface of the reflective sheet. It is characterized in that they are arranged so as to become dense and sparse again, and the densest part is located on the reflection sheet side.

According to the invention, of the end faces of the transparent substrate,
A reflection sheet that reflects the light emitted from the auxiliary lighting device is provided on the end surface facing the end surface on which the auxiliary lighting device is arranged. By providing this reflection sheet, the light transmitted through the end surface facing the end surface on which the auxiliary lighting device is arranged can be emitted to the display unit of the reflective liquid crystal display device, and the light from the auxiliary lighting device can be effectively used. Can be used.

Further, the spacers are arranged so that the spacer becomes sparser and denser and becomes sparser again from the auxiliary lighting device side end face toward the reflection sheet side end face, so that the densest portion is located on the reflection sheet side. It is located in. Due to the light reflected by the reflection sheet, the light amount of the portion closest to the reflection sheet side end face increases, and the light amount of the portion closer to the inner side from the portion closest to the reflection sheet side end face becomes the smallest. By providing the spacers as described above, it is possible to make the spacers in the portion where the light amount is the smallest the densest and to uniformly emit the light to the display portion of the reflective liquid crystal display device.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a reflective liquid crystal display device 31 having a touch panel in which a resistive film type touch panel 11, an auxiliary lighting device 21 and a reflective liquid crystal display device 12 are integrated will be described with reference to the drawings. . FIG. 1 shows the configurations of the resistive film type touch panel 11 and the auxiliary lighting device 21. The upper ITO film 2 vapor-deposited on the touch panel upper input side film 1 and the lower ITO film 4 vapor-deposited on the transparent substrate 3 arranged on the lower side are bonded together by an adhesive material 5. With such a structure, a space can be formed between the upper ITO film 2 and the lower ITO film 4. This interval is called the air layer 18. Further, an insulating spacer 6 is provided on the lower ITO film 4.

The auxiliary lighting device 21 is provided on the end surface of the transparent substrate 3 of the resistive film type touch panel 11 and uses the transparent substrate 3 as a light guide. In the auxiliary lighting device 21, the light source 8 is arranged in the light source fixing holder 7, and the reflection sheet 9 having a high reflectance is provided inside the light source fixing holder 7 in order to effectively use the light from the light source 8. Has been. Also, the light source 8
The reflection sheet 10 having a high reflectance is attached to the end surface of the transparent substrate 3 on which is not arranged.

FIG. 2 shows the touch panel 11 and the auxiliary lighting device 21 shown in FIG.
2 is a schematic view of a reflective liquid crystal display device 31 provided with a touch panel that is disposed on the upper side of and is integrally assembled by the chassis 14.

The resistive film type touch panel 11 used in the present invention has an upper ITO film 2 deposited on a touch panel upper input side film 1 and a lower side I deposited on a transparent substrate 3.
An air layer 18 is provided in the display area so that the TO film 4 does not come into contact with the air. By pressing a point on the touch panel upper input side film 1, a point on the upper ITO film 2 and a point on the lower ITO film 4 come into contact with each other. As a result, a current flows between the upper ITO film 2 and the lower ITO film 4, and when the contact position changes, the coordinates can be detected by the change in the current and the resistance value. The role of the insulating spacer 6 is to prevent malfunction due to light contact with the touch panel upper input film 1.

How to use the reflection type liquid crystal display device 31 equipped with the touch panel when the display on the display unit 13 becomes difficult to see due to the dark surroundings will be described. The optical path emitted from the auxiliary lighting device 21 will be described with reference to FIGS. 2 and 3. When light is incident on the transparent substrate 3, the difference between the refractive index of the lower ITO film 4 of about 2.0 and the refractive index of the air layer 18 between the lower ITO film 4 and the upper ITO film 2 of 1.0. As a result, total internal reflection occurs at a critical angle of about 30 degrees at the interface between the lower ITO film 4 and the air layer 18. Further, the transparent substrate 3 and the air layer 2 under the transparent substrate 3
Due to the difference in refractive index from 8, total reflection occurs at a critical angle of about 42 degrees.

Therefore, like the incident light 15, the light propagates through the transparent substrate 3. The incident light 15 propagating in the transparent substrate 3 strikes the spacer 6 to cause light scattering, and becomes diffused light 16, which diffused light 16 escapes to the lower side of the transparent substrate 3. Then, the diffused light 16 is reflected by the display unit 13 of the reflective liquid crystal display device 12, and the display of the reflective liquid crystal display device 12 can be seen.

When the surroundings are sufficiently bright, the auxiliary lighting device 2
The light source 8 of No. 1 is not turned on. The external light 17 passes through the resistive film type touch panel 11 and the transparent substrate 3 and is reflected by the display unit 13 of the reflective liquid crystal display device 12, whereby the display unit 1
You can see the display of 3.

The transparent substrate 3 disposed below the resistive film type touch panel 11, the lower ITO film 4, and the spacer 6
Will be described with reference to FIG. The shape of the transparent substrate 3 can be determined by simulation so that light can be used efficiently. The spacer 6 is arranged so that the light propagated inside the transparent substrate 3 is uniformly directed downward.
The placement can be determined by simulation.

A screen printing method which is an example of a method of forming the spacer 6 will be described with reference to FIG. A mask 51 matching the pattern of the spacer 6 is prepared. The mask 51 is placed on the lower ITO film 4 and the transparent substrate 3. From there, the transparent resin 53 is poured, and the transparent resin 53 is poured into the pattern of the mask 51 by the roller 52 or the like. When the mask 51 is removed, the dot-patterned spacers 6 are formed on the lower ITO film 4.

The photo process method will be described with reference to FIG. A photosensitive acrylic resin 61, which is the material of the spacer 6, is applied onto the lower ITO film 4.
A resist 62 is applied thereon. UV light is irradiated from above the photomask 63 that matches the pattern of the spacer 6. Upon development, the same resist pattern as the photomask 63 is formed. The resist pattern is etched. When the resist is peeled off, the spacer 6
Pattern is formed.

As the method for forming the spacer 6, the screen printing method and the photo process method have been described, but other forming methods may be used.

The spacer 6 may be made of a transparent material such as epoxy resin, polyester resin, silicone resin, acrylic resin, polyurethane resin or the like. Further, in the photo process method, a transparent resin such as a photosensitive acrylic resin or a photosensitive polyester resin can be obtained by forming it in the form of fine dots. The shape of the spacer is also not particularly limited and may be hemispherical, cylindrical, conical, or the like.

Next, the dot pattern of the spacer 6 will be described. When the cold cathode tube, which is the light source 8 of the auxiliary lighting device 21, is a single-lamp type, as shown in FIG. 7, the dot pattern of the spacer 6 becomes sparse or dense as the distance from the light source 8 increases. The dot pattern of the spacer 6 is not the densest because the vicinity of the arrow B is the closest and the vicinity of the reflection sheet 10 (the arrow A) is slightly brighter due to the reflection sheet 10.

When the cold-cathode tube which is the light source 8 of the auxiliary lighting device 21 is of a two-light type, the dot pattern of the spacer 6 becomes sparse to dense toward the middle as shown in FIG. . The area near the arrow D is densest, and the central portion (arrow C) is the light of the cold cathode tubes on both sides, so the dot pattern of the spacer 6 is not the densest.

It goes without saying that the dot pattern distribution of the spacer 6 differs depending on the type of the light source 8 and the location of the light source 8.

The materials of the resistive film type touch panel upper input side film 1 and the transparent substrate 3 may be transparent materials such as acrylic transparent resin, polyethylene terephthalate, epoxy resin, polyester resin, silicone resin and polyurethane resin.

The material of the upper ITO film 2 and the lower ITO film 4, which are transparent electrodes (movable electrodes), is not particularly limited to ITO (indium tin oxide), and tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide can be used. Metal oxides such as, may be used.

The light source 8 is not particularly limited, and examples thereof include a white LED and a fluorescent lamp.

The material of the adhesive material 5 used in the present invention is not particularly limited, but a material having a high reflectance is used in order to prevent light leakage of light incident on the transparent substrate.

According to the present invention, even in an environment from direct sunlight to darkness, it can be used as a reflective liquid crystal display device equipped with a touch panel.

According to the present invention, by integrating the resistive film type touch panel, the auxiliary lighting device and the reflection type liquid crystal display device, it is possible to reduce the size and weight and further reduce the cost. Further, when the surroundings become dark and the display becomes difficult to see, the display can be viewed by using the auxiliary lighting device.

Further, by using the transparent substrate 3 below the resistive film type touch panel as a light guide, the parts can be made common, the cost can be reduced, and the size can be further reduced.

Further, since the transparent substrate provided under the resistive film type touch panel is also used as the light guide of the auxiliary illuminating device, the structure on the reflection type liquid crystal display device is reduced. Therefore, the attenuation of external light can be reduced. That is, when the external light is used without using the auxiliary lighting device, it is possible to suppress the attenuation of the external light caused by the surface reflection on the light guide of the auxiliary lighting device, and the display quality of the reflective liquid crystal display device, The contrast does not decrease.

Further, by using the spacer of the touch panel to form a sparse and dense pattern, the light incident on the transparent substrate 3 can be uniformly directed to the display portion of the reflective liquid crystal display device. In addition, since the spacers are simply made into a dense and dense pattern, they do not cause a cost increase.

[0048]

As described above, according to the present invention, when the transparent substrate forming the lower part of the resistive film type touch panel is used as the light guide of the auxiliary lighting device, it is possible to display by utilizing external light. It is possible to suppress the attenuation of external light that has been conventionally caused by the surface reflection at the light guide of the auxiliary lighting device that is separately provided, and the display quality and contrast of the reflective liquid crystal display device are not deteriorated.

Further, by providing a spacer having a sparse and dense dot pattern corresponding to the distance from the auxiliary lighting device on the lower electrode of the resistive film type touch panel, the light emitted from the auxiliary lighting device is The light from the auxiliary lighting device can be effectively used because the light can be uniformly emitted to the display portion of the reflective liquid crystal display device arranged below the resistive film type touch panel. Furthermore, by integrating the resistive film type touch panel, the auxiliary lighting device, and the reflective liquid crystal display device, it is possible to reduce the size and weight and further reduce the cost.

Further, according to the present invention, by forming the spacer with a transparent member, it is possible to prevent the shadow of the spacer and the spacer itself from being visually recognized in a dot shape, thereby improving the display quality of the reflection type liquid crystal display device. be able to.

Further, according to the present invention, the spacers are arranged so as to become sparser to denser and closer to the reflective sheet side end face from the auxiliary lighting device side end face to the reflective sheet side end face, and the densest portion is located on the reflective sheet side. By arranging so that it is located,
Make the spacer where the light amount is the smallest the densest,
It is possible to uniformly emit light to the display unit of the reflective liquid crystal display device.

[Brief description of drawings]

FIG. 1 is an auxiliary lighting device 21 and a resistive film type touch panel 1.
1 is a schematic view of 1.

FIG. 2 is an auxiliary lighting device 21 and a resistive film type touch panel 1.
3 is a schematic view of a reflective liquid crystal display device 31 including a touch panel that is integrated with FIG.

FIG. 3 is a diagram showing a relationship between light incident on a transparent substrate 3 and its angle.

FIG. 4 is a schematic view of a spacer 6 and a transparent substrate 3.

FIG. 5 is a diagram showing a method of forming a spacer 6 by a screen printing method.

FIG. 6 is a diagram showing a method of forming a spacer 6 by a photo process method.

FIG. 7 is a diagram showing a pattern of a spacer 6 when the light source is a single-lamp type.

FIG. 8 is a diagram showing a pattern of a spacer 6 when the light source is a two-lamp type.

FIG. 9 is an auxiliary lighting device 42 and a resistive film type touch panel 4.
1 is a schematic view when 1 and a reflective liquid crystal display device 43 are separately provided.

[Explanation of symbols]

1 Touch panel upper input film 2 Upper ITO film 3 transparent substrate 4 Lower ITO film 5 Adhesive 6 spacers 7 Light source holder 8 light sources 9,10 Reflective sheet 11 Resistive touch panel 12 Reflective liquid crystal display device 13 Display 14 chassis 15 incident light 16 diffused light 17 External light 18,28 Air layer 21 Auxiliary lighting device 31 reflective liquid crystal display device with touch panel

Claims (3)

(57) [Claims] 1. A resistive film type touch panel is disposed on a display portion of a reflective liquid crystal display device, and an auxiliary lighting device is disposed on an end face of a transparent substrate which constitutes a lower portion of the resistive film type touch panel. To be used as a light guide of the auxiliary lighting device so that the light emitted from the auxiliary lighting device is emitted to the display unit of the reflective liquid crystal display device disposed below the resistive film type touch panel. In addition, a reflective liquid crystal display device having a touch panel, characterized in that a spacer having a sparse and dense dot pattern corresponding to the distance from the auxiliary lighting device is provided on the lower electrode of the resistive film type touch panel. . 2. The reflective liquid crystal display device having a touch panel according to claim 1, wherein the spacer is made of a transparent material. 3. A reflective sheet is provided on an end surface of the transparent substrate facing the end surface on which the auxiliary lighting device is arranged, and the spacer becomes sparser and denser from the end surface on the auxiliary lighting device side to the end surface on the reflective sheet side. The reflective liquid crystal display device with a touch panel according to claim 1, wherein the reflective liquid crystal display device is arranged so as to be sparse again, and the densest portion is located on the reflective sheet side.