KR100398755B1 - Front light-combined touch panel device - Google Patents

Abstract

The front light unit 15 including the reflective liquid crystal display device 5, the transparent light guide plate 3 having a thickness of 0.3 to 2.0 mm, and the light source 4 disposed on the end surface thereof, and the transparent touch panel 14 include a reflection plate. (6) layered sequentially.

Description

Front light integrated touch panel device {FRONT LIGHT-COMBINED TOUCH PANEL DEVICE}

Background Art Conventionally, small and lightweight portable electronic devices with liquid crystal displays have been developed and commercialized. Transmissive liquid crystal displays used in liquid crystal displays require a back light, and in portable electronic devices, they are driven by batteries such as dry batteries and rechargeable batteries. In particular, color display devices required for sub-notebook personal computers, PDAs, and digital cameras require a backlight using a cold cathode fluorescent tube of high brightness as a light source, so that the power consumption of the backlight is increased to drive the battery. The time is significantly reduced.

Therefore, it is considered to use a reflective liquid crystal display device that does not require a backlight for portable electronic devices in order to reduce power consumption. This type of liquid crystal display is being commercialized. The reflection type liquid crystal display device uses less backlight and consumes less power. In addition, the reflective liquid crystal display device exhibits excellent visibility even under external light when used outdoors. Therefore, from these viewpoints, the reflective liquid crystal display device is suitable for use in portable electronic devices.

However, in order to use the reflective liquid crystal display device in an environment such as indoors or at night where sufficient external light is not obtained, it is necessary to illuminate the reflective liquid crystal display device from the surface, and thus, the light source disposed on the reflective liquid crystal display device. A lighting device (front light unit) equipped with a has been proposed.

For example, it is proposed that the lighting device be mounted on a lid portion or a receivable pillar of the reflective liquid crystal display device. As a lighting apparatus, there exist some which light sources, such as a cold cathode fluorescent tube, a light bulb, and LED, illuminate a reflection type liquid crystal display device directly. In addition, a resin plate or film having light diffusing property or a resin plate or film having light condensation may be disposed on the front surface of these light sources to illuminate the reflective liquid crystal display device indirectly.

An illuminating device in which a light emitter is mounted on a cover portion of a reflective liquid crystal display device has a thick cover, which impairs portability of the portable electronic device. In addition, the lid of the reflective liquid crystal display device is originally intended to protect the reflective liquid crystal display device from an impact from the outside. Therefore, it is not preferable to arrange the light-emitting body which is susceptible to impact on the cover portion.

In addition, the lighting apparatus attached to the posts may damage the posts and the light source due to inadvertent handling during use, and the configuration becomes complicated because a storage mechanism is required when not in use.

The present invention relates to a front light integrated touch panel device having a front light for illumination of a liquid crystal display device integrated with a touch panel (touch sensing panel). In particular, the front light integrated touch panel device according to the present invention is a portable electronic device having a reflective liquid crystal display device, such as a wireless telephone, a mobile phone, a scientific calculator, a sub-notebook personal computer, a personal digital assistant (PDA), a digital camera, a video. Suitable for use in cameras, business communication devices, etc.

1 is a cross-sectional view showing a front light integrated touch panel device according to a first embodiment of the present invention;

2 is a perspective view showing a portable electronic device of a specific example incorporating a front light-integrated touch panel device according to a first embodiment;

3 is a perspective view showing a portable electronic device of another embodiment incorporating a front light-integrated touch panel device according to a first embodiment;

4 is a cross-sectional view showing in detail the configuration of the front light-integrated touch panel device of the first embodiment;

5 is a cross-sectional view showing a front light integrated touch panel device according to a second embodiment of the present invention;

6 is a cross-sectional view showing a front light integrated touch panel device according to a third embodiment of the present invention;

7 is a cross-sectional view showing a front light integrated touch panel device according to a fourth embodiment of the present invention;

8 is a cross-sectional view showing the configuration of the peripheral device and the front light unit used in the front light-integrated touch panel device of the fifth embodiment of the present invention;

9 is a cross-sectional view showing the configuration of the peripheral device and the front light unit used in the front light-integrated touch panel device of the sixth embodiment of the present invention;

10 is a cross-sectional view showing the configuration of the peripheral device and the front light unit used in the front light-integrated touch panel device of the seventh embodiment of the present invention;

11 is a cross-sectional view showing the configuration of the peripheral device and the front light unit used in the front light-integrated touch panel device of the eighth embodiment of the present invention;

12 is a cross-sectional view showing the configuration of the peripheral device and the front light unit used in the front light-integrated touch panel device of the ninth embodiment of the present invention;

13 is a cross-sectional view showing the configuration of an example of a conventional front light;

14 is an explanatory diagram showing a conventional front light having a touch panel bonded thereto;

15 is a cross-sectional view showing a front light integrated touch panel according to a tenth embodiment of the present invention;

16 is a cross-sectional view showing in detail the configuration of a front light-integrated touch panel device according to an eleventh embodiment of the present invention;

17 and 18 are partially enlarged views showing two examples of a light guide plate of the front light integrated touch panel device of FIG. 16;

19 is a cross-sectional view showing in detail the configuration of the front light-integrated touch panel device according to the eleventh embodiment of the present invention.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a front light integrated touch panel device capable of uniformly illuminating a reflective liquid crystal display without impairing the portability of a portable electronic device.

In order to achieve the above object, according to the first embodiment of the present invention, a front light unit including a reflective liquid crystal display device on a reflecting plate, a transparent light guide plate, and a light source disposed at an end surface thereof; A front light integrated touch panel device configured to sequentially layer a transparent touch panel is provided.

According to a second embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the transparent touch panel is a transparent touch panel of a resistive model and mediates a transparent resin layer. The lower portion of the transparent touch panel may be configured to engage the upper portion of the front light unit.

According to the third embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the transparent touch panel is a film-type resistive touch panel, and is formed through a transparent resin layer. The lower portion of the transparent touch panel may be configured to be attached to the upper portion of the front light unit.

According to a fourth embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the light guide plate is formed on at least one surface of the ink having a transparent or semitransparent resin having a refractive index greater than that of the light guide plate. Thus, a fine polygonal or circular dot gradation pattern having an area ratio of 60% or less and a dot size of 200 μm or less is provided.

According to a fifth embodiment of the present invention, there is provided a front light-integrated touch panel device according to a fourth embodiment, wherein the light guide plate is composed of a transparent or semi-transparent resin having a refractive index larger than that of the light guide plate, and has a pigment having light diffusivity. The dot gradation pattern formed by the ink containing is provided.

According to a sixth embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the light guide plate may be formed on at least one surface thereof with a transparent or translucent resin layer having a refractive index greater than that of the light guide plate. good.

According to a seventh embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the light guide plate has a fine corrugated pattern on at least one surface thereof.

According to an eighth aspect of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the light guide plate is at least on one side thereof, and the light incident end surface of the light guide plate on the side of the reflective liquid crystal display device side. It has a 30-500 micrometer pitch and the several prism of 30-100 micrometers width in parallel.

According to a ninth embodiment of the present invention, there is provided a front light integrated touch panel device according to the first embodiment, wherein the transparent touch panel includes an upper electrode sheet having an upper electrode formed on a lower surface of a film-shaped insulating substrate. ), And a lower electrode sheet having a lower electrode formed on an upper surface of a plate-shaped or film-shaped insulating substrate having a fine film on its upper surface, and the upper electrode sheet and the lower electrode sheet are disposed to face each other through an air layer. The light guide plate was bonded to the back of the transparent touch panel via the transparent resin layer to integrate the transparent touch panel and the front light unit.

According to a tenth aspect of the present invention, there is provided a front light-integrated transparent touch panel device according to the ninth embodiment, wherein the recess of the microcavity portion is composed of many fine grooves formed on the entire upper surface of the insulating substrate.

According to an eleventh embodiment of the present invention, there is provided a front light-integrated transparent touch panel device according to the tenth embodiment, wherein the area ratio of the microgrooves away from the light source is larger than the area ratio of the microgrooves near the light source.

According to a twelfth embodiment of the present invention, there is provided a front light-integrated transparent touch panel device according to a ninth embodiment, wherein a film-shaped insulating substrate having a fine film portion is placed before the film-shaped insulating substrate is molded. Many fine fins are provided by transparent fine beads.

According to a thirteenth embodiment of the present invention, there is provided a front light-integrated transparent touch panel device according to a ninth embodiment, wherein the concave portion of the microcavity portion is formed as a film by coating or printing an ink containing transparent microbeads. do.

According to a fourteenth embodiment of the present invention, there is provided a front light-integrated transparent touch panel device according to the thirteenth embodiment, wherein the film has a dot gradation having a larger area ratio at a point away from the light source than near the light source. It is formed into a pattern.

According to a fifteenth embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the light guide plate has a flat surface on the side of the touch panel and a flat surface on the side of the liquid crystal display device. A flat portion 33a and an inclined portion 33b having an inclined surface are provided, and light incident from the side surface of the light guide plate is reflected in the plane of the flat portion inside the light guide plate, and the light exits out from the inclined surface of the inclined portion.

According to a sixteenth embodiment of the present invention, there is provided a front light-integrated touch panel device according to a fifteenth embodiment, wherein an angle defined between a cross section in which a light source of the light guide plate is disposed and a surface of the light guide plate on the side of the touch panel side. Is 88 to 92 °, and an angle defined between the plane of the flat portion and the inclined surface of the inclined portion adjacent to the flat portion in a direction opposite to the inclined surface of the light guide plate on the surface on the side of the liquid crystal display device is larger than the angle and smaller than 180 degrees.

According to a seventeenth embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the transparent layer has a smaller refractive index than the light guide plate and is formed on the surface of the light guide plate on the side of the liquid crystal display device. It is further provided.

According to an eighteenth embodiment of the present invention, there is provided a front light-integrated touch panel device according to the first embodiment, wherein the light guide plate has a thickness of 0.3 mm to 2.0 mm.

Before continuing the description of the invention, it should be noted that like parts are indicated by like reference numerals in the accompanying drawings.

1 is a cross-sectional view showing a front light integrated touch panel device according to a first embodiment of the present invention. Fig. 2 is a perspective view showing the portable electronic device 1A of the specific example in which the front light-integrated touch panel device of the first embodiment is incorporated. Fig. 3 is a perspective view showing the portable electronic device 1B of another embodiment incorporating the front light-integrated touch panel device of the first embodiment. 4 is a cross-sectional view showing in detail the configuration of the front light-integrated touch panel device according to the first embodiment.

5 to 7 are cross-sectional views illustrating the front light integrated touch panel device according to the second to fourth embodiments of the present invention, respectively.

8 to 12 are cross-sectional views illustrating configurations of a peripheral device and a front light unit used in the front light integrated touch panel device according to the fifth to ninth embodiments of the present invention.

15 is a cross-sectional view illustrating a configuration of a peripheral apparatus and a front light unit of a front light integrated touch panel according to a tenth embodiment of the present invention.

16 to 19 are cross-sectional views illustrating configurations of a peripheral device and a front light unit of a front light integrated touch panel device according to an eleventh embodiment of the present invention.

1 to 12 and 15 to 19, reference numerals 1, 1A and 1B denote portable electronic devices, 3 denote rectangular light guide plates, 4 denote light sources, 5 denote rectangular reflective liquid crystal displays, 6 denote rectangular reflectors, and 7 reference numerals. Is a rectangular liquid crystal display, 8 (8A, 8B, 8C, 8D, 8E) is a light diffusion layer, 9 is a rectangular upper electrode plate, 10 is an adhesive layer, 11, 11A, 11B is a rectangular lower electrode plate, 12 is a transparent resin layer, 13 A silver rectangular support, 14 a rectangular transparent touch panel, and 15 a reflective liquid crystal display illuminating device (front light unit).

As shown in Fig. 1, the front light-integrated touch panel device of the first embodiment is disposed on the reflection plate 6, on the reflection type liquid crystal display device 5, on the transparent light guide plate 3 having a thickness of 0.3 to 2.0 mm, and on its cross section. The front light unit 15 made of the light source 4 and the transparent touch panel 14 are sequentially stacked.

The front light integrated touch panel device includes a portable electronic device 1 having a reflective liquid crystal display device 5 and a transparent touch panel 14, such as a wireless telephone, a mobile phone, a scientific calculator, a sub-notebook personal computer, a PDA, and a digital device. It is applied to a camera, a video camera, a business communication device, and the like (see FIGS. 2 and 3).

2 shows a perspective view of an example of the portable electronic device 1. The portable electronic device 1 realizes an input function by means of a transparent touch panel 14 which is a pen input device provided at the top of the display unit. The portable electronic device 1 of the other specific example of FIG. 3 is equipped with the keyboard 100 as an input device, and also has the transparent touch panel 14 as an input device also on the display surface.

As the transparent touch panel 14, what is called a resistive film method may be used. For example, as shown in FIG. 4, the lower electrode plate 11A made of an insulating substrate such as a glass plate or a film provided with a lower electrode made of a transparent conductive film and a polygonal or circular microdot spacer on the surface thereof. ) And an upper electrode plate 9 made of an insulating substrate such as a flexible film having an upper electrode made of a transparent conductive film, for example. By pressing a part of the surface of the transparent touch panel 14 from the surface on the input side, the two electrodes can be brought into contact with each other to electrically conduct input. In addition, the transparent touch panel 14 may be applied to a capacitive method, an optical method, and the like.

The front light-integrated touch panel device includes a reflecting plate 6 that reflects external light and light from the front light unit 15, a reflective liquid crystal display device 5, a light guide plate 3, and a light source 4 disposed at an end thereof. The front light unit 15 and the transparent touch panel 14 may be configured in combination with each other (see FIG. 4).

In the second embodiment, the lower electrode plate 11A of the transparent touch panel 14 may be used as the flexible film 11B having an electrode as in the upper electrode plate 9 (see FIG. 5). This method is called a film type, and can be reduced in weight by using a flexible film instead of glass for the lower electrode, and prevents the transparent touch panel 14 from being easily damaged. In general, in order to provide rigidity to the film-type transparent touch panel 14 itself, a transparent resin plate made of transparent resin such as acrylic resin or polycarbonate resin is disposed below the lower electrode plate 11B. Attach as.

In the third embodiment, the transparent touch panel 14 having the glass lower electrode plate 11A and the front light unit 15 are made of a transparent resin layer 12 such as a transparent adhesive or a transparent gel. It may also work together as an intermediary (see Fig. 6).

The transparent resin layer 12 is obtained by adding a common transparent adhesive such as an acrylic resin such as an acrylic ester copolymer, a urethane resin, a silicone resin, a rubber resin, or the like. Urethane series pressure sensitive adhesives, acrylic series or natural polymer materials and the like can be used as the polymer pressure sensitive adhesive. By such a configuration, the air layer existing between the transparent touch panel 14 and the front light unit 15 can be eliminated. Due to the difference between the refractive index of air (1.0) and the refractive indexes of glass or transparent resin (1.4 to 1.7), if the air layer is present between the lower electrode plate 11A or 11B and the light guide plate 3, the transmittance is lowered. Therefore, the light transmittance between the light guide plate 3 and the transparent touch panel 14 is improved by bonding the light guide plate 3 and the transparent touch panel 14 together with the transparent resin layer 12 to remove the air layer.

In the fourth embodiment, when the film-like transparent touch panel 14 having the lower electrode plate 11B made of a film having the same electrode as the upper electrode plate 9 is used, the support plate is omitted and the front light is omitted. The transparent touch panel 14 may be bonded to the unit 15 via the transparent resin layer 12 (see FIG. 7). In this configuration, the support 13 of the lower electrode plate 11B of the transparent touch panel 14 is used together as the light guide plate 3 of the front light unit 15, and the support 13 and the light guide plate 3 of FIG. Remove the air layer between). Therefore, the transmittance is improved. Since the film-type transparent touch panel 14 has a flexible structure, the joining process of the light guide plate 3 and the transparent touch panel 14 can be made easy.

In each embodiment, in the reflective liquid crystal display device 5, external light passes through the light guide plate 3 and the reflective liquid crystal display device 5 of the front light unit 15 from the uppermost transparent touch panel 14 side. The light is reflected by the reflecting plate 6 and exits through the reflective liquid crystal display 5, the light guide plate 3, and the transparent touch panel 14. Since external light passes through each part of the display portion twice, the transmittance is considerably lower than that of the transmissive liquid crystal display device. Therefore, it is important to remove the two layers, the air layer and the support 13, in order to improve the transmittance. In particular, the air layer has a large difference in refractive index compared with the light guide plate 3 or the transparent resin layer 12, so that the loss due to reflection of the interface between the air layer and another layer is large.

For example, when a transparent acrylic plate is used as the transparent light guide plate, due to the difference in refractive index between the acrylic plate and the air layer, a loss of nearly 7% of transmittance arises from surface reflection. Therefore, removing the air layer has a good effect on the improvement of the transmittance.

In this example, the 7% loss can be reduced.

Next, the front light unit 15 will be described.

Since the light guide plate 3 is disposed on the reflective liquid crystal display device 5 in a superimposed manner, the light guide plate 3 is required to have sufficient light transmittance and not interfere with the visibility of the liquid crystal display.

As the light guide plate 3, a thin plate shape made of a transparent resin may be used. As the transparent resin, acrylonitrile styrene copolymer resin, cellulose acetobutylate resin, cellulose propionate resin, polymethyl pentene resin, polycarbonate resin, polystyrene resin or polyester resin and the like which are excellent in transparency and light guiding property can be used.

In the above-described first embodiment, since the transparent touch panel 14 is disposed above, the distance between the upper surface and the lower surface of the light guide plate 3, that is, the surface of the light guide plate on the side of the reflective liquid crystal display device 5, is increased. If the distance between the surface and the input surface of the light guide plate from the surface on the side of the transparent touch panel 14 is too large, parallax will occur and will shift. In the case where the thickness of the light guide plate 3 is set to about 0.3 to 2.0 mm, the light guide plate 3 on the surface on the reflection type liquid crystal display device 5 side and the light guide plate 3 on the surface on the transparent touch panel 14 side. ), The distance of the input surface can be kept below 3.0mm. It is preferable that this thickness is 0.3-1.5 mm. When the thickness of the light guide plate 3 is less than 0.3 mm, it is difficult to process the light guide plate 3, and sufficient light cannot be obtained from the end face of the light guide plate 3 where the light source 4 is located. When the thickness exceeds 2.0 mm, since the thickness and weight of the front light unit 15 increase, portability is lacking.

If the upper and lower surfaces of the light guide plate 3 are in a mirror face state, the light is transmitted to the end face opposite to the light incident end surface of the light guide plate 3 by repeating total reflection. As a result, little light is emitted to the surface. In order to solve this problem, the light diffusion layer 8 is provided on at least one surface of the reflection type liquid crystal display device 5 side or the display side surface of the light guide plate 3 so that the light in the light guide plate 3 is reflected. It functions to emit light toward the display device 5 side. By arranging the light guide plate 3 provided with such a diffusion layer 8 on the reflective liquid crystal display device 5, sufficient irradiation can be performed on the reflective liquid crystal display device 5. Since the light from the light source 4 propagates through the inside of the light guide plate 3 to the end face opposite to the light incident end surface of the light guide plate 3, the entire reflection type liquid crystal display device 5 can be irradiated. .

It is necessary that the light diffusing layer 8 of the light guide plate 3 has sufficient light transmittance when using external light and does not interfere with the visibility of the liquid crystal display. Therefore, it is conceivable to configure the light diffusing layer 8 to have a fine shape, especially a gradation pattern, a wrinkle shape, a prism shape, and the like.

Usually, the dot gradation formed by screen printing is used as the light-diffusion layer 8 in a backlight. In this case, the dot gradation has a dot diameter of 300 µm or more, and the pigment is added to enhance the light diffusing function. When the light diffusing layer 8 is used as the front light unit 15 as it is, the ratio of dots in the liquid crystal display unit 7 is high, which hinders the visibility of the display unit together with external light use and when the front light unit 15 is turned on. Done.

Next, according to the fifth embodiment of the present invention, the light diffusing layer 8 of the front light unit used in the front light integrated touch panel device is clearly shown. For example, a dot gradation pattern is formed on the surface of the light guide plate 3 on the side of the reflective liquid crystal display device 5 by using an ink mainly composed of a transparent or translucent resin having a higher refractive index than the light guide plate 3, and thus light The diffusion layer 8A is formed. The surface on the display side of the light guide plate 3 can be in a mirrored state (see FIG. 8). The visibility of the reflection type liquid crystal display device 5 can be improved by using the gradation whose dot diameter is 200 micrometers or less and making the area ratio 60% or less. The light incident on the inside of the light guide plate 3 is totally reflected inside the light guide plate 3, and the cross-sectional branched light facing the light incident end surface of the light guide plate 3 is sent. Further, light is emitted from dots formed on the surface of the reflection type liquid crystal display device 5 of the light guide plate 3. Therefore, the reflective liquid crystal display device 5 is irradiated. By adjusting the gradation ratio, the amount of light emitted from the light diffusion layer 8A can be adjusted, so that the reflective liquid crystal display device 5 can be uniformly illuminated.

In the front light unit used in the front light-integrated touch panel device according to the sixth embodiment of the present invention, the dot gradation pattern is provided with a transparent or semi-transparent resin having a refractive index larger than that of the light guide plate 3 as a main component, and is light diffused. A dot gradation pattern may be formed on the surface on the display side of the light guide plate 3 with the same dot diameter and area ratio as described above by using an ink containing a pigment having property, thereby forming the light diffusion layer 8B. (See FIG. 9). In this case, light incident on the light guide plate 3 diffuses diffusely by dots of the light diffusing layer 8B formed on the surface of the light guide plate 3 on the display side, and is diffused on the reflective liquid crystal display device 5 side. It is emitted to the surface to illuminate the reflective liquid crystal display 5. Because of the diffusive pigment contained in the ink of the light diffusion layer 8B, the light can be emitted more efficiently. By adjusting the gradation ratio, the light output amount in the light diffusion layer 8B can be adjusted. Therefore, the reflective liquid crystal display device 5 can be illuminated evenly.

In order to form a dot gradation pattern, printing methods, such as gravure printing and screen printing, may be used. According to the molding simultaneous transfer method, the dot gradation pattern can be formed at the same time as the molding of the light guide plate 3, which is suitable. In the simultaneous molding method, a transfer material having a transfer layer formed on a base sheet is inserted into a molding die, and resin is filled in the mold by injection molding to obtain a resin molded product, and at the same time, the transfer material is adhered to the surface of the molded product. It is a method of peeling a base sheet and transferring a transfer layer to a to-be-transferred object surface.

In the front light unit of the front light-integrated touch panel device according to the seventh embodiment of the present invention, fine wrinkles may be formed as the light diffusion layer 8D such that display visibility is not significantly attenuated (see FIG. 10). The wrinkled shape of the light diffusing layer 8D of the light guide plate 3 may be formed in the mold inner surface and formed when the light guide plate 3 is molded. In addition, in order to form the light-diffusion layer 8D on the light guide plate 3 surface, you may perform the fine mat process of nearly 30 micrometers diameter. Because of the corrugation or the mat shape of the light diffusing layer 8D, the light incident from the end face of the light guide plate 3 is scattered inside the light guide plate 3, and some light is emitted to the reflective liquid crystal display device 5 side.

As in the front light unit of the front light integrated touch panel device according to the eighth embodiment of the present invention, the light guide plate 3 is parallel to the light incident end surface of the light guide plate 3 on the surface of the reflective liquid crystal display device 5 side. A plurality of prisms may be formed as the light diffusion layer 8E (see FIG. 11). Light incident on the light guide plate 3 irradiates the reflective liquid crystal display device 5 from the prism face of the light diffusion layer 8E. Examples of the shape of the prism of the light diffusion layer 8E include an equilateral triangle and a lens shape. By varying the size and pitch of the prism of the light diffusing layer 8E in proportion to the distance from the light incident end face, the light emission balance of the light diffusing layer 8E can be controlled. The shape of the prism of the light diffusion layer 8E may be set to a pitch of 30 to 500 µm and a width of 30 to 100 µm so as not to adversely affect the visibility.

According to each embodiment of the present invention, the light diffusing layer 8 may be formed of a transparent or translucent resin having a refractive index larger than that of the light guide plate 3.

Specifically, in the ninth embodiment of the present invention, the front light unit of the front light integrated touch panel device includes a light diffusion layer 8C of transparent resin having a refractive index larger than that of the light guide plate 3 on the display side of the light guide plate 3. May be formed (see FIG. 12). Light incident on the light guide plate 3 is reflected at the interface between the light diffusing layer 8C and the light guide plate 3 due to the difference in refractive index, and is further emitted to the air layer to irradiate the reflective liquid crystal display device 5. In this configuration, since dots and the like do not exist on the surface of the light guide plate 3, they hardly affect the visibility of the reflective liquid crystal display device 5.

The light source is disposed in the cross section of the light guide plate 3. The light source is disposed on at least one side of the rectangular light guide plate 3. A cold cathode fluorescent tube, LED, or the like may be used as the light source 4.

The shape of the cathode tube used may be a straight line, an L-shaped tube over two adjacent sides, or a U-shaped tube over three adjacent sides.

4 to 7, the reflector 49 may be disposed to efficiently collect the light emitted from the light source 4 on the light incident end surface of the light guide plate 3. As the reflector 49, for example, a metal plate having a surface reflecting light such as silver, aluminum, platinum, nickel, or chromium on its surface, in particular silver, aluminum, or the like is surface coated by vacuum deposition or sputtering. Do. Even if a light diffusing material such as TiO ₂ or BaSO ₄ is mixed in a resin such as polyester, or a light diffusing reflector 6 or a light diffusing film which is formed by foaming a resin such as polyester to give light diffusibility, good.

As described above, by integrating the front light unit 15 and the transparent touch panel 14 through the transparent resin layer 12, the transmittance can be improved. When the film type transparent touch panel 14 is used, the support body 13 can be removed, and the apparatus is further simplified and the transmittance is improved.

Next, a front light unit of a front light integrated touch panel device according to a tenth embodiment of the present invention is capable of sufficiently illuminating a reflective liquid crystal display device by eliminating the following inconvenience without lowering the transmittance.

That is, when used in an environment where sufficient light is not obtained, such as indoors or at night, it is necessary to illuminate the reflective liquid crystal display device from the front surface. With this configuration, the flat light (front light) is installed in front of the reflective liquid crystal display, and the environment light and the front light (e.g., SID, 95 Digest, page 375, CY Tai, H. Zou, PKTai) are provided. Will be used. The front light is provided with a light source, such as a set of a cold cathode fluorescent tube or the like, at a cross section of the light guide plate 103 made of a resin such as a transparent resin, along a fine fin 108 such as a prism formed on the front surface of the light guide plate 103 ( See FIG. 13). While repeating total reflection inside the light guide plate 103, the light beam obtained from the end face of the light guide plate 103 is guided inward. A portion of the light beam is reflected by the convex portion 108 at an angle, so that the beam is easy to exit to the surface of the reflective liquid crystal display device side of the light guide plate 103 and exits from the light guide plate 103 to be reflected out. Examine the display.

In most conventional portable electronic devices, the transparent touch panel is disposed in front of the transmissive liquid crystal display device to provide an input function from the liquid crystal display surface. The transparent touch panel includes an upper electrode sheet 109 having an upper electrode of a transparent conductive film formed on a lower surface of a film-shaped insulating substrate, and a lower electrode formed of a lower electrode of a transparent conductive film formed on an upper surface of a plate or film-shaped insulating substrate. The sheet 111 is included. The upper electrode sheet 109 and the lower electrode sheet 111 are disposed to face each other through an air layer between the electrodes. By pressing a part of the panel surface from the input surface, the two electrodes can be contacted and electrically conducted. In such a configuration (for example, Japanese Patent Laid-Open No. 61-131314), although a slight air layer exists between the transparent touch panel and the transmissive liquid crystal display device, the touch panel is deteriorated by the surface reflection at the interface. It adheres to a transmissive liquid crystal display device via an adhesive layer or a peeling sheet.

On the other hand, the touch panel of the above-described structure can not be attached to the reflective liquid crystal display device using the front light as an illumination source. Since the fine fin 108 of the light guide plate 103 of the front light is designed to emit a part of the light beam obtained from the cross section of the light guide plate 103 by the reflection at the interface with the air layer, the reflective liquid crystal display device. The removal of the air layer by the attachment of the touch panel to the front surface of the light guide plate of the front light makes it impossible for the fine film portion 108 to emit the light beam to the reflective liquid crystal display (see FIG. 14).

In order to solve this problem, the front light unit of the front light integrated touch panel device according to the tenth embodiment of the present invention is configured as follows.

As shown in FIG. 15, the light guide plate 3 may be configured so as not to have the fine fin 58 on its upper surface. The air layer that can be removed by attachment to the transparent touch panel 14 can be used as the light guide plate 3 even though the micro-section 58 is present. In some cases, the light beam obtained from the end face to reach the front surface of the light guide plate 3 results in the transparent touch panel 43 via the transparent resin layer or the re-peelable sheet. Most of the light beams incident on the transparent touch panel 14 are totally reflected by the front surface of the lower electrode sheet 11, that is, the interface between the lower electrode and the air layer. The light beam is sent to the end face opposite to the light incident end surface of the light guide plate 3 while repeating the total reflection at the interface and the total reflection at the back surface of the light guide plate 3. In the meantime, since the insulating substrate of the lower electrode sheet 11 provides a fine film on the upper surface, a part of the light beam incident on the transparent touch panel 14 is the lower electrode formed on the insulating substrate of the lower electrode sheet 11. It is not totally reflected by the interface between the air layer and the air layer, and therefore, the interface between the lower electrode and the air layer is formed with a fine fin. A portion of the light beam is reflected instead of having an angle, so that the beam is easily emitted to the reflective liquid crystal display (see FIG. 15). The front light integrated touch panel configured as described above is superimposed on the reflective liquid crystal display 5, whereby the reflective liquid crystal display 5 is sufficiently illuminated.

The concave portion of the fine concave portion 58 may be constituted by many fine concave portions formed on the entire upper surface of the insulating substrate of the lower electrode sheet 11. The fine convex portions are formed in any shape, such as a concave conical or weak mortar shape, which enables the light beam to be reflected at an easy angle with respect to the light beam so as to exit the reflective liquid crystal display device. After the insulating substrate is molded, the fine grooves are treated with heat and pressure by the concave and convex rolls of the surface of the insulating substrate, or the fine grooves with respect to the cavity surface defined by the mold inner wall or the molding sheet. It is obtained by forming a shape corresponding to the negative portion, whereby the insulating substrate transfers the shape when the resin plate is molded by a method such as a mold. When the touch panel is used with external light, the recess diameter is preferably 5 to 40 µm in order to exhibit sufficient light transmittance and to prevent attenuation of the visibility of the liquid crystal display unit 7.

Preferably, the area ratio of the fine grooves near the light source 4 is set smaller than the area ratio of the fine grooves away from the light source 4. The area ratio is changed by changing the size and pitch of the fin in accordance with the distance from the light source 4. Therefore, it is possible to control the light output balance of the fine light section 58, so that the reflective liquid crystal display device 5 can be uniformly illuminated.

In the film-shaped insulating substrate having the fine fin portions 58, many fine fin portions can be formed by inserting transparent fine beads before forming the film-shaped insulating substrate. The beads are made of a resin that is the same as the material of the insulating substrate or has a small difference in refractive index in order to maintain the transmittance of the insulating substrate itself. Each beads present on the film surface may be completely covered or partially exposed with the resin constituting the film. The diameter of the beads is preferably 5 to 40 µm in order to have sufficient light transmittance when using external light and not to attenuate the visibility of the liquid crystal display 7.

The concave portion of the fine concave portion 58 can be formed as a film by coating or printing an ink containing transparent fine beads. The beads are made of resin or glass that is the same as the material of the insulating substrate or has a small difference in refractive index in order to maintain the transmittance of the insulating substrate itself. Beads present on the surface of the coating may be exposed without being completely covered with the coating or a portion thereof. The diameter of the beads is preferably 5 to 140 µm in order to have sufficient light transmittance when using external light and to avoid attenuation of visibility of the liquid crystal display unit 7.

It is preferable to form the film of the ink containing transparent beads into the dot gradation pattern which has a larger area ratio in the place away from the light source 4 than the area ratio near the light source 4. In order to change the area ratio of the film, the size and pitch of the dots are changed in accordance with the distance from the light source 4. Therefore, it is possible to control the light output balance of the fine light section 58, so that the reflective liquid crystal display device 5 can be uniformly illuminated. Printing methods such as gravure printing and screen printing can be used to form gradation patterns. Dot shape is not specifically limited, Arbitrary shapes, such as a circle and a polygon, can be employ | adopted.

In the eleventh embodiment, as shown in Fig. 16, in the light guide plate 33 made of acryl as in one example, a flat portion 33a and a liquid crystal display device having a surface parallel to the other surface of the surface on the touch panel side ( The inclination part 33b which has the surface parallel to each other inclined with respect to the other surface alternately arrange | positioned at the one surface of the surface of 5) side is formed. The light incident surface of the light guide plate 33 is perpendicular to the other surface. The light beam incident from the cross section is formed by the flat surface 33a parallel to the other surface facing the touch panel of the light guide plate 33 and the other surface of one side of the surface on the side of the liquid crystal display device 5 of the light guide plate 33. It is totally reflected, and it exits only from the inclination part 33b, and irradiates the liquid crystal display device 5 by this. The light irradiated to the liquid crystal display device 5 passes through the light guide plate 33 and the touch panel again, is reflected by the reflecting surface under the liquid crystal through the liquid crystal, and exits out. Therefore, the liquid crystal display of the device using the reflective liquid crystal panel can be recognized in an environment where sufficient light is not obtained.

17 and 18 show examples of the inclined portion 33b inclined with respect to the other surface and the flat portion 33a parallel to the other surface on one surface of the light guide plate on the surface on the liquid crystal panel side of FIG. 16.

The angle α between the flat portion 33a and the inclined portion 33b in FIG. 17 is 90 degrees. In this case, the light reaching the inclined portion 33b is assumed to be at the same angle as the light incident surface, and is totally emitted to the outside of the light guide plate 33.

In Fig. 18, the angle? Between the flat portion 33a and the inclined portion 33b is set larger than 90 degrees and smaller than 180 degrees. If the height from the plane of the inclined portion 33b, i.e., the thickness of the inclined portion 33b is the same as in Figs. 17 and 18, since the area of the inclined portion 33b in Fig. 18 is larger, a greater amount of light than in Fig. 17 It may exit from the inclined portion 33b of FIG.

Preferably, the angle defined between the end face on which the light source 4 of the light guide plate 33 is disposed and the surface of the light guide plate 33 on the side of the touch panel side is 88 to 92 °, and the plane of the flat part 33a and the liquid crystal The angle between the inclined surface of the inclined portion 33b adjacent to the flat portion 33a in the direction opposite to the inclined surface of the light guide plate on the surface on the display device 5 side is larger than the angle and smaller than 180 °.

However, in forming or cutting the light guide plate 33, due to the accuracy of processing, the angle of the light incident surface relative to the other surface of the surface on the touch panel side is not always exactly 90 °. These days, the accuracy of angles is within ± 2 ° in molding and cutting techniques. In the case of the considered angle, total reflection of the light incident from the flat part 33a on one side of the light incidence plane on the other side facing the touch panel of the light guide plate 33 and on the side of the liquid crystal panel side In order to do so, the angle of light incident with respect to the side surface as the light incident surface needs to be smaller than 44 °. The refractive index of the light guide plate 33 at this time is larger than 1.44.

On the other side of the light guide plate facing the liquid crystal display device 5 for the inclined portion 33b adjacent to the flat portion 33a in a direction opposite to the light incident surface, for emitting light from the inclined portion 33b. The angle α of the flat portion 33a having a surface parallel to the other surface facing the touch panel, which needs to be present, needs to be 90 to 180 degrees. When the angle is 90 degrees, the inclined portion 33b becomes parallel to the side as the light incident surface.

On the surface on the side of the liquid crystal display device 5, even if the distance between the continuous flat portion 33a and the inclined portion 33b on one side of the light guide plate 33 is uniform, the distance is emitted according to the position of the light source 4. Can be changed for.

In one modification of the eleventh embodiment, the reflection reduction processing on one surface of the light guide plate 33 on the surface on the liquid crystal display device 5 side improves the transmittance of the entire front light-integrated touch panel device.

In some reflection reduction processing, the transparent layer 34 having a lower refractive index than the light guide plate 33 is directly processed, for example, by forming a film of a material having a low refractive index with respect to the resin surface of the light guide plate 33, thereby forming a liquid crystal display. It is formed on one surface of the light guide plate 33 on the surface on the device side. When inorganic fluorides such as metallic fluorides such as MgF ₂ (refractive index 1.38) and metallic oxides such as SiO ₂ (refractive index 1.46) are used, a vacuum deposition method or the like can be used. When an organic material is used, the fluorine monomer is plasma polymerized, thereby forming a transparent layer 34 made of a film on the resin surface. A method such as dip coating can also be used for organic matter.

Further, the film having the transparent layer 34 having a refractive index smaller than that of the light guide plate 33 has one surface of the light guide plate 33 by using a transparent adhesive having a refractive index equal to or less than that of the light guide plate and having a refractive index equal to or greater than the refractive index of the film. And thus constitute a low refractive index layer for the interface of the air layer.

In particular, in FIG. 19, the light guide plate 33 is formed with a transparent layer 34 on one surface facing the liquid crystal display device 5. The transparent layer 34 has a refractive index smaller than the refractive index of the light guide plate 33 and larger than the refractive index of the air layer. The light guide plate 33 is formed of an acrylic resin, and the transparent layer 34 is formed by dip coating of a fluorine monomer. Surface reflection on the other side of the light guide plate 33 caused by the presence of an interface to the air layer causes a decrease in transmittance. Therefore, the resin layer 34 is arranged to achieve the reflection reduction process, thereby reducing the reflectance at the interface to improve the transmittance.

This transparent layer 34 may be applied to each light guide plate 3 of the previous embodiment to achieve the same effect.

According to this structure, since the air layer normally between the touch panel and the light guide of the device with the touch panel and the embedded front light is removed, the air layer and the touch panel at the interface between the bottom surface and the air layer and the top surface of the light guide plate are removed. Loss of light due to reflection is prevented, thereby increasing the transmittance of the entire apparatus. In addition, the lower electrode sheet of the touch panel has a light diffusing function surface at the interface to the air layer, so that light is effectively emitted from the front light.

As described above, in the structure of a portable electronic device having a reflective liquid crystal display as a display portion, in the case of the front light and the touch panel laminated on the display portion, the bottom surface of the transparent touch panel and the top surface of the light guide plate of the front light are transparent adhesive layers. The light diffusing function, which is glued by and is usually provided on the surface of the light guide plate, is achieved on one side of the light guide plate of the front light on the side of the liquid crystal unit, so that the transmittance of the entire apparatus is improved. In use under daylight, the front light can efficiently emit light without losing visibility.

[Example 1]

By forming a fine pattern on the surface, a polyethylene terephthalate film having a matt resin mixed therein is inserted into an injection molding die. After the molding mold is clamped, transparent acrylic resin is injected therein. The polyethylene terephthalate film is separated from the molding article after the molding mold is opened.

In this method, a rectangular transparent acrylic plate with a thickness of 1.5 mm is obtained as a light guide plate. The light guide plate has a light-diffusion layer in which a fine fin of about 30 mu m is irregularly formed on one side thereof. The other side of the light guide plate is mirror surface.

A cold cathode fluorescent tube of 2 mm diameter is arranged as a line light source on one of the long sides of the light guide plate. A reflective film having a silver deposition surface on the side of the cold cathode fluorescent tube is provided as a reflector on the circumference of the cold cathode fluorescent tube not facing the light guide plate. In addition, the reflective film of foamed polyethylene terephthalate is attached to the end face of the light guide plate opposite the light incident end face by a pressure sensitive adhesive double-coated tape.

A glass substrate having an ITO (Indium Tin Oxide) conductive film on its surface is used as a lower electrode plate, and a polyethylene terephthalate film having an ITO conductive film on its surface is used as an upper electrode plate of a transparent touch panel. The upper surface of the light guide plate is attached to the lower side of the touch panel by a transparent adhesive gel of acrylic resin having a thickness of 0.2 as the transparent resin layer.

The front light integrated touch panel device configured as described above is installed in parallel to the liquid crystal panel on the liquid crystal display panel. The light diffusing layer of the light guide plate is disposed on the side opposite to the liquid crystal panel, and the reflecting plate is disposed below the liquid crystal panel.

The light incident on the light guide plate from the light source is partially scattered by a fine matte shape, and is emitted to the liquid crystal panel, thereby irradiating the liquid crystal panel after exiting the liquid crystal panel. Irradiation light passing through the liquid crystal layer is reflected by the reflecting plate under the liquid crystal panel, passes through the liquid crystal layer again, and passes through the light guide plate protruding outward.

In the above structure, the liquid crystal display has sufficient visibility in all cases where the front light unit is turned on and turned off.

[Example 2]

The light guide plate is formed in the same manner as in Example 1.

Both the lower electrode plate and the upper electrode plate of the transparent touch panel are made of polyethylene terephthalate film having an ITO conductive film on each surface. The upper surface of the light guide plate is attached to the lower surface of the transparent touch panel by a transparent adhesive layer of acrylic resin having a thickness of 50 µm as the transparent resin layer. In addition, the light guide plate of the front light unit of this structure operates to support the transparent touch panel.

In all cases where the front light unit is turned on and turned off, the liquid crystal display of the obtained front light integrated touch panel device exhibits sufficient visibility. By operating the light guide plate of the front light unit as a support, the structure is simplified because the support generally required for supporting the film-type transparent touch panel is removed. In addition, the reduction of the parts count contributes to the improvement of the transmittance.

The present invention is configured as described above and operates as follows.

In the touch panel device with a front light integrated according to the present invention, a front light unit comprising a reflective liquid crystal display device on a reflecting plate, a transparent light guide plate having a thickness of 0.3 to 2.0 mm, and a light source set disposed at its end face, and a transparent touch panel. This is layered sequentially. Since the front light unit is thin and does not increase the size or weight of the portable electronic device, the front light unit does not reduce the portability of the portable electronic device. Since the light source is received by the portable electronic device main body, the protection of the light source is not lacking.

The front light unit is superimposed on the reflective liquid crystal display device. Therefore, there is no fear of damaging the use of the front light unit. Even when not in use, the storage device of the front light unit is unnecessary.

In addition, although this invention was demonstrated with respect to each said embodiment, it is not limited to this and can be variously modified and implemented in the range which does not deviate from the summary of invention.

Claims (18)

delete delete delete delete delete delete delete delete On the reflecting plate 6, a front light unit 15 including a reflective liquid crystal display device 5, a transparent light guide plate 3, and a light source 4 disposed on its end face, and a transparent touch panel 14 are provided. Sequential, The transparent touch panel includes an upper electrode sheet having an upper electrode formed on a lower surface of a film-shaped insulating substrate, and a lower electrode sheet having a lower electrode formed on an upper surface of a plate-shaped or film-shaped insulating substrate provided with a fine film on its upper surface. , The upper electrode sheet and the lower electrode sheet are opposed to each other via the air layer between the electrodes, The front light integrated touch panel device comprising the transparent touch panel and the front light unit integrated by attaching the light guide plate to the rear surface of the transparent touch panel via a transparent resin layer. 10. The touch panel apparatus of claim 9, wherein the concave portion of the fine fin portion comprises a plurality of fine grooves formed on the entire upper surface of the insulating substrate. The front light integrated touch panel device according to claim 10, wherein an area ratio of the microgrooves away from the light source is larger than an area ratio of the microgrooves near the light source. 10. The touch panel integrated touch panel according to claim 9, wherein the film-shaped insulating substrate having the micro-shaped portions has a large number of micro-shaped portions by transparent fine beads inserted before the film-shaped insulating substrate is molded. Device. 10. The front light integrated touch panel device according to claim 9, wherein the concave portion of the fine concave portion is formed as a film by coating or printing an ink containing transparent fine beads. The front light-integrated touch panel device according to claim 13, wherein the coating is formed of a dot gradation pattern having a larger area ratio at a location away from the light source than near the light source. On the reflecting plate 6, a front light unit 15 including a reflective liquid crystal display device 5, a transparent light guide plate 3, and a light source 4 disposed on its end face, and a transparent touch panel 14 are provided. Sequential, The light guide plate includes a flat portion 33a having a flat surface on the surface of the touch panel side, and a flat portion 33a having a flat surface on the surface of the liquid crystal display device side, and an inclined portion 33b having an inclined surface. And the light incident from the side surface of the light guide plate is reflected by the plane of the flat portion inside the light guide plate, and the light is emitted outward from the inclined surface of the inclined portion. The angle defined between a cross section in which the light source of the light guide plate is disposed and a surface of the light guide plate on the side of the touch panel side is 88 to 92 °, the flat surface of the flat portion and the liquid crystal display device side. And an angle defined between the inclined surfaces of the inclined portion adjacent to the flat portion in a direction opposite to the inclined surface of the light guide plate on the surface, wherein the angle is greater than the angle and less than 180 °. On the reflecting plate 6, a front light unit 15 including a reflective liquid crystal display device 5, a transparent light guide plate 3, and a light source 4 disposed on its end face, and a transparent touch panel 14 are provided. Sequential, And a transparent layer (34) having a refractive index smaller than that of the light guide plate and formed on the surface of the light guide plate on the side of the liquid crystal display device side. delete