JP2000047178A - Reflection type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection type liquid crystal display device capable of viewing the display even in a sufficiently dark environment and capable of being made small in size, light in weight and low in cost when using the reflection type liquid crystal display incorporated with a resistance film method touch panel. SOLUTION: In this reflection type liquid crystal display device 31, a resistance film system touch panel 11 is arranged above a display panel 13 of the reflection type liquid crystal display 12, an auxiliary illumination device 21 is arranged on the end face of a transparent substrate 3 arranged under the resistance film system touch panel 11, and they are integrated by a chassis. The transparent substrate 3 under the resistance film method touch panel 11 is used as a light guide body. Incident light 15 which propagates from the auxiliary illumination device 21 into the transparent substrate 3, strikes against spacers 6, becomes diffused light 16, passes through the lower side of the transparent substrate 3, reflects on the display panel 13 of the reflection liquid crystal display 12, and thus, the display can be viewed. The spacers 6 has a coarse and close pattern on a lower ITO film 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device to which an auxiliary lighting device is added, and a resistive touch panel being integrated.

[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 miniature, the liquid crystal itself does not emit light, but displays characters and images by adjusting the amount of light transmitted from a specific light source.

[0003] Liquid crystal display devices can be broadly classified into transmission type liquid crystal display devices and reflection type liquid crystal display devices. A transmissive liquid crystal display device has a light source (backlight) on the back of a liquid crystal cell.
A surface light source such as a fluorescent tube or an EL is provided. On the other hand, since the reflective liquid crystal display device performs display using ambient light, there is an advantage that a backlight is not required and power consumption is small. Furthermore, in a very bright place exposed to direct sunlight, the transmissive liquid crystal display device has an advantage in that the visibility is reduced, whereas the reflective liquid crystal display device has a clearer visibility. are doing. For this reason,
The reflection type liquid crystal display device has been applied to portable information terminals and mobile computers, which have been increasingly demanded in recent years.

Further, as an information input device used for a portable information terminal or a mobile computer, a resistive touch panel arranged on the front surface of a liquid crystal display is often used. The resistance film type touch panel is inexpensive and has good assemblability such that it can be easily attached to the front of the display unit.

However, the reflection type liquid crystal display has the following problems. Since the reflection type liquid crystal display device uses ambient light for display, the degree of display luminance greatly depends on the surrounding environment, and the display cannot be recognized in darkness such as at night. In particular, in a reflection type liquid crystal display device using a color filter for colorization, or a reflection type liquid crystal display device using a polarizing plate, the above problem is extremely large, and when sufficient ambient light cannot be obtained, , An auxiliary lighting device is required.

[0006] Further, since the reflection type liquid crystal display device has a reflection plate on the back surface, the backlight used in the transmission type liquid crystal display device cannot be used. Accordingly, a transflective liquid crystal display device using a half mirror as a reflection plate has been proposed, but the display quality is not necessarily good.

Therefore, a method of irradiating a reflective liquid crystal display device from the front has been proposed as auxiliary lighting means when the surroundings are dark. Conventionally, a liquid crystal display device having such auxiliary lighting means has been proposed in JP-A-6-324332 and JP-A-9-212448.

In Japanese Patent Application Laid-Open No. 6-324332, a light guide is disposed 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. Hei 9-21448 describes various embodiments in which a movable illumination unit is provided in front of a display unit in consideration of storage so that sufficient display can be recognized even in a dark place. I have.

[0009]

However, the above-mentioned prior art has various problems. JP-A-6
In Japanese Patent No. 324332, an auxiliary lighting device is arranged behind a reflective liquid crystal display device. In addition, when a resistive touch panel, which is an input detection device, is provided, the thickness of the two mechanisms of the auxiliary illumination device and the input detection device is added, and portability is significantly impaired.

In Japanese Patent Application Laid-Open No. Hei 9-212448, an auxiliary lighting device is disposed in front of a reflection type liquid crystal display device. In addition, if a resistive touch panel, which is an input detection device, is provided, the auxiliary illumination device and the input detection device can be used.
The additional thickness of the two mechanisms significantly impairs portability.

[0011] As shown in FIG.
3, auxiliary lighting device 42, resistive touch panel 4
1 exist separately, and in a bright place, the auxiliary lighting device 4
Since the second light source 48 is not turned on, light reaching the surface of the reflective liquid crystal display device 43 is attenuated by the external light 47 that has passed through the resistive touch panel 41 and reaches the surface of the reflective liquid crystal display device 43 due to surface reflection on the light guide 44. The contrast of the display screen of the liquid crystal display device 43 is reduced. That is, it is necessary to reduce the configuration above the reflective liquid crystal display device 43 as much as possible.

Furthermore, since the auxiliary lighting device of the reflection type liquid crystal display device and the resistive touch panel are separately provided,
Weight gain cannot be avoided.

Further, since an auxiliary lighting device for a reflection type liquid crystal display device and a resistive touch panel are separately provided,
The assembly work and the unit cost of parts also increase.

In portable electronic devices, it is particularly important to design a compact and lightweight electronic device. For this reason, it is necessary to study a reduction in the size and weight of the entire device constituting the device.

That is, in a reflection type liquid crystal display device,
If a resistive touch panel and an auxiliary lighting device are used at the same time, the device will be large, expensive, and heavy, resulting in poor commercial value.

The present invention relates to a reflective liquid crystal display device,
A resistive touch panel located in front of the reflective liquid crystal display device and an auxiliary lighting device are integrated.

[0017]

According to a first aspect of the present invention, there is provided a transparent substrate provided on a display portion of a reflective liquid crystal display device, wherein a resistive touch panel is disposed on the display portion of the reflective liquid crystal display device. Characterized in that an auxiliary lighting device is arranged on an end face of the device.

According to a second aspect of the present invention, the transparent substrate provided under the resistive touch panel is also used as a light guide of the auxiliary lighting device.

According to a third aspect of the present invention, light incident on a transparent substrate provided below the resistive touch panel is displayed on a reflective liquid crystal display device disposed below the resistive touch panel. A spacer composed of a dense / dense pattern is provided on the lower electrode of the resistive touch panel so as to be emitted to the portion.

The operation of the above configuration will be described.

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

According to the second aspect of the present invention, the surroundings are dark,
When using the auxiliary lighting device, since the transparent substrate provided under the resistive touch panel is also used as a light guide of the auxiliary lighting device, light from the light source of the auxiliary lighting device is reflected. The display unit of the liquid crystal display device can be uniformly illuminated, and the light from the light source of the auxiliary lighting device can be used effectively. In addition, the reduction in the number of components above the reflective liquid crystal display device can reduce the attenuation of external light.
In other words, when external light is used without using the auxiliary lighting device, attenuation of external light caused by surface reflection on the light guide of the auxiliary lighting device can be suppressed, and the display quality of the reflective liquid crystal display device can be reduced. The contrast does not decrease.

According to the third aspect of the present invention, the surroundings are dark,
In the case where the auxiliary lighting device is used, light incident on the resistive touch panel can be directed to the display unit of the reflective display device. Further, by adjusting the distance between the spacers, it is possible to uniformly illuminate the display section of the reflective liquid crystal display device.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflection type liquid crystal display device 31 in which a resistive touch panel 11 and an auxiliary lighting device 21 are integrated.
The embodiment will be described with reference to the drawings. In FIG.
2 shows a configuration of a resistive touch panel 11 and an auxiliary lighting device 21. The upper ITO film 2 deposited on the touch panel upper input side film 1 and the lower ITO film 4 deposited on the transparent substrate 3 arranged on the lower side are adhered by the adhesive 5. With such a configuration, the upper IT
There is a space between the O film 2 and the lower ITO film 4. This interval is called an air layer 18. Further, an insulating spacer 6 is provided on the lower ITO film 4.

The auxiliary lighting device 21 is provided on an end face of the transparent substrate 3 of the resistive touch panel 11, and uses the transparent substrate 3 as a light guide. In the auxiliary lighting device 21, the light source 8 is disposed in the light source fixing holder 7, and a reflection sheet 9 having a high reflectance is provided inside the light source fixing holder 7 in order to effectively use light from the light source 8. Have been. Light source 8
The reflective sheet 10 having a high reflectance is attached to the end face of the transparent substrate 3 where the above-mentioned is not arranged.

FIG. 2 shows that the touch panel 11 and the auxiliary lighting device 21 shown in FIG.
Is a reflection type liquid crystal display device 31 which is disposed on the upper side and integrated by the chassis 14.

The resistive touch panel 11 used in the present invention comprises an upper ITO film 2 deposited on the input film 1 on the upper side of the touch panel and a lower I film deposited on the transparent substrate 3.
An air layer 18 is interposed in the display area so that the TO film 4 does not contact. By pressing one point of the input side film 1 on the touch panel upper part, one point of the upper ITO film 2 and one point of the lower ITO film 4 come into contact. 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 reflective liquid crystal display device 31 when the surroundings are dark and the display on the display unit 13 is difficult to see will be described. The light path emitted from the auxiliary lighting device 21 is shown in FIG.
This will be described with reference to FIG. When light enters the transparent substrate 3, the lower ITO film 4 has a refractive index of about 2.0 and the lower ITO film 4 has a lower refractive index.
Refractive index of air layer 18 between film 4 and upper ITO film 2
Due to the difference of 0, total reflection occurs at a critical angle of about 30 degrees at the interface between the lower ITO film 4 and the air layer 18. Furthermore, due to the difference in the refractive index between the transparent substrate 3 and the air layer 28 below the transparent substrate 3, total reflection occurs at a critical angle of about 42 degrees.

Therefore, light propagates through the transparent substrate 3 like the incident light 15. The incident light 15 propagated in the transparent substrate 3 hits the spacer 6 and causes scattering of the light to become diffused light 16, and the diffused light 16 passes below 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 viewed.

If the surroundings are sufficiently bright, the auxiliary lighting device 2
One light source 8 is not turned on. The external light 17 passes through the resistive touch panel 11 and the transparent substrate 3 and is reflected by the display unit 13 of the reflection type liquid crystal display device 12, thereby forming the display unit 1.
3 can be seen.

The transparent substrate 3 disposed below the resistive 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 arrangement of the spacer 6 is such that the light propagated inside the transparent substrate 3 is uniformly directed downward.
The arrangement can be determined by simulation.

A screen printing method as an example of a method of forming the spacer 6 will be described with reference to FIG. A mask 51 that matches the pattern of the spacer 6 is prepared. The mask 51 is placed on the lower ITO film 4 and the transparent substrate 3. A transparent resin 53 is poured from above, and the transparent resin 53 is poured into the pattern of the mask 51 by using a roller 52 or the like. When the mask 51 is removed, a spacer 6 in a dot pattern is formed on the lower ITO film 4.

The photo process will be described with reference to FIG. On the lower ITO film 4, a photosensitive acrylic resin 61, which is a material of the spacer 6, is applied.
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 removed, the spacer 6
Is formed.

Although the method of forming the spacer 6 has been described with respect to the screen printing method and the photo process method, other forming methods may be used.

The material of the spacer 6 may be a transparent material such as an epoxy resin, a polyester resin, a silicone resin, an acrylic resin, and a polyurethane resin. 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 into fine dots. The shape of the spacer may be hemispherical, cylindrical, conical, or the like, and is not particularly limited.

Next, the dot pattern of the spacer 6 will be described. When the cold-cathode tube as the light source 8 of the auxiliary lighting device 21 is of a single-lamp type, the dot pattern of the spacer 6 becomes sparser and denser as the distance from the light source 8 increases, as shown in FIG. The area near the arrow B is the densest, and the area near the reflective sheet 10 (arrow A) is slightly brighter by the reflective sheet 10, so the dot pattern of the spacer 6 is not the densest.

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

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

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

The material of the upper ITO film 2 and the lower ITO film 4 which are the transparent electrodes (movable electrodes) is not particularly limited to ITO (indium tin oxide), but tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide. , Etc. 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 5 used in the present invention is not particularly limited, but a material having a high reflectivity is used to prevent light from leaking into the transparent substrate.

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

According to the present invention, by integrating the resistive 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. When the surroundings become dark and the display becomes difficult to see, the display can be viewed by using an auxiliary lighting device.

Further, by using the transparent substrate 3 under the resistive touch panel as a light guide, components can be shared, the cost can be reduced, and the size can be further reduced.

Further, since the transparent substrate provided under the resistive touch panel is also used as a light guide of the auxiliary lighting device, the number of components on the reflective liquid crystal display device is reduced. Accordingly, the attenuation of external light can be reduced. In other words, when external light is used without using the auxiliary lighting device, attenuation of external light caused by surface reflection on the light guide of the auxiliary lighting device can be suppressed, and the display quality of the reflective liquid crystal display device can be reduced. The contrast does not decrease.

Further, by forming a dense / dense pattern using the spacer of the touch panel, light incident on the transparent substrate 3 can be uniformly directed to the display section of the reflective liquid crystal display device. Further, since the spacers are merely formed in a sparse and dense pattern, they do not cause a cost increase.

[0048]

By integrating the resistive touch panel, the auxiliary lighting device and the reflection type liquid crystal display device, it is possible to reduce the size, weight and cost. When the surroundings become dark and the display becomes difficult to see, the display can be viewed by using an auxiliary lighting device.

When an auxiliary lighting device is used because the surroundings are dark, the transparent substrate provided under the resistive touch panel also serves as a light guide of the auxiliary lighting device. The light from the light source can uniformly illuminate the display section of the reflective liquid crystal display device, and the light from the light source of the auxiliary lighting device can be used effectively.

Further, since the transparent substrate provided under the resistive touch panel is also used as the light guide of the auxiliary lighting device, the number of components on the reflective liquid crystal display device is reduced. Accordingly, the attenuation of external light can be reduced. In other words, when external light is used without using the auxiliary lighting device, attenuation of external light caused by surface reflection on the light guide of the auxiliary lighting device can be suppressed, and the display quality of the reflective liquid crystal display device can be reduced. The contrast does not decrease.

When the surroundings are dark and an auxiliary lighting device is used, light incident on the resistive touch panel is
It can be directed to the display unit of the reflective display device. Further, by adjusting the distance between the spacers, it is possible to uniformly illuminate the display section of the reflective liquid crystal display device.

[Brief description of the drawings]

FIG. 1 shows an auxiliary lighting device 21 and a resistive touch panel 1
FIG.

FIG. 2 shows an auxiliary lighting device 21 and a resistive touch panel 1
FIG. 1 is a schematic view of a reflection type liquid crystal display device 31 which is integrated with a liquid crystal display device 1.

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 illustrating 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 when a single light source is used.

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

FIG. 9 shows an auxiliary lighting device and a resistive touch panel 4.
FIG. 4 is a schematic view in a case where a reflective liquid crystal display device 1 and a reflective liquid crystal display device 43 are separately provided.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Touch-panel upper input film 2 Upper ITO film 3 Transparent substrate 4 Lower ITO film 5 Adhesive material 6 Spacer 7 Light source fixing holder 8 Light source 9 10 Reflective sheet 11 Resistive touch panel 12 31 Reflective liquid crystal display device 13 Display unit 14 Chassis 15 incident light 16 diffused light 17 external light 18 28 air layer 21 auxiliary lighting device

Claims (3)

[Claims] 1. A resistive touch panel is disposed on a display unit of a reflective liquid crystal display device, and an auxiliary lighting device is disposed on an end surface of a transparent substrate provided below the resistive touch panel. A reflective liquid crystal display device characterized by the above-mentioned. 2. The reflective liquid crystal display device according to claim 1, wherein a transparent substrate provided under the resistive touch panel also serves as a light guide of the auxiliary lighting device. 3. The light incident on a transparent substrate provided below the resistive touch panel is emitted to a display section of a reflective liquid crystal display device disposed below the resistive touch panel. 2. The reflection type liquid crystal display device according to claim 1, wherein a spacer made of a dense / dense pattern is provided on a lower electrode of the resistive touch panel.