JP2003262736A - Method for manufacturing light guide member and light guide member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a thin light guide member while keeping the utilization efficiency of light from a light source. <P>SOLUTION: The method for manufacturing a light guide member 1 having an exit part 11 and an entrance part 12 for light comprises a process of forming prism grooves 11a by pressing on a substrate to prepare the exit part 11 and an integration process to integrate the entrance part 12 with the obtained exit part 11. The utilization efficiency of light from a light source may decrease when the light guide member 1 is made thinner. However, by separately preparing the entrance part 12 from the exit part 11 and then integrating them, the exit part 11 can be made thinner while the entrance part 12 can be made into any desired form. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide member used for a backlight or a front light of a liquid crystal display device or the like.

[0002]

2. Description of the Related Art Backlights and frontlights have been proposed as devices for illuminating liquid crystal display panels and the like. These devices introduce light into the light guide member by providing a light source on the side surface of the light guide member made of a transparent substrate, and diffuse the light by a light output pattern such as a prism groove provided on the surface of the light guide member. , Realizes surface emission. Such a light guide member is generally called a light guide plate because it has a flat plate shape.

On the other hand, as a method of forming such a light emitting pattern, for example, a method of forming a light emitting pattern on a light guide member by an injection molding method is known. But,
According to this method, there is a problem in that the shape of the light emitting pattern may be defective due to insufficient filling of the resin material, and there is a limit to the thinning of the light guide member.

Therefore, for example, Japanese Unexamined Patent Publication No. 11-14725.
Japanese Unexamined Patent Publication No. 5 (1994) proposes a method of forming a light output pattern by pressing the material of the light guide member. According to the method by this press working, it is possible to reduce the shape defect and to make the light guide member thinner.

[0005]

However, when the light guide member is made thinner by forming the light emitting pattern by pressing, the thickness of the portion where the light from the light source enters becomes thinner, and the utilization efficiency thereof is reduced. .

Therefore, an object of the present invention is to realize a thin light guide member while maintaining the utilization efficiency of light from a light source.

[0007]

According to the present invention, there is provided a method of manufacturing a light guide member having a light emitting part and a light entering part, wherein the light emitting pattern is formed by pressing on a base material. There is provided a method of manufacturing a light guide member, comprising: a step of forming a section; and an integrally forming step of integrally forming the light entering section on the created light emitting section.

Further, according to the present invention, there is provided a light guide member in which the light entrance portion is integrally formed with the light exit portion formed by forming a light exit pattern on a base material by pressing. .

Further, according to the present invention, a light guide member having a light exit portion and a light entrance portion, wherein the light entrance portion is integrally formed on the substantially plate-like light exit portion having a light exit pattern formed thereon. The light guide member is characterized in that the light incident portion has a light source side end portion which is arranged to face the light source, and the thickness of the end portion is thicker than the thickness of the light emitting portion. It

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. 1A is a sectional view showing the structure of a front light A using a light guide member 1 according to an embodiment of the present invention, and FIG. 1B is a backlight B using the light guide member 1. It is sectional drawing which shows a structure.

First, the front light A will be described with reference to FIG. The front light A is the light emitting section 1
1, a light guide member 1 having a light entrance portion 12, a reflective liquid crystal display panel 2 arranged below the light exit portion 11, and a linear light source 3 that allows light to enter the light entrance portion 12. A reflecting member 4 which partially surrounds the light source 3 and whose inner surface is mirror-finished.

The light output portion 11 of the light guide member 1 is a rectangular plate-shaped member, and a plurality of prism grooves 11a formed in a linear shape with a triangular cross section are formed in parallel on the upper surface as a light output pattern. There is. Various types of light output patterns have been proposed in addition to the prism groove 11a, and a method of adjusting the density of the prism grooves 11a to form a gradation pattern has also been proposed and can be appropriately selected. In FIG. 1, the prism grooves 11a are simply represented for convenience of description, but in practice, they are generally formed as a fine pattern having a pitch and a depth of about several tens of μm. Target.

The light incident part 12 has a light source side end 12a arranged to face the light source 3, is connected to the light exit part 11 at the light exit side end 12b, and is formed integrally with the light exit part 11.
Here, in the present embodiment, the light source side end portion 12 of the light incident portion 12 is provided.
The thickness of a is thicker than the thickness of the light emitting portion 11. This aims at reducing the thickness of the entire front light A by making the light emitting section 11 as thin as possible, while the light source 3
This is for improving the utilization efficiency of light from.

That is, as the thickness of the light emitting portion 11 becomes smaller, the width of the side surface also becomes smaller. Therefore, when the light from the light source 3 is incident on the side surface, the light utilization efficiency is reduced. A light entrance section 12 is provided separately from the section 11.
Moreover, by making the thickness of the light source side end portion 12a equal to or more than a certain value, the front light A as a whole is made thinner and the light utilization efficiency is improved. Further, by disposing the liquid crystal display plate 2 below the light incident part 12 and arranging it substantially directly below the light emitting part 11, when disposing the liquid crystal display plate 2 close to the light emitting part 11, The front light A as a whole is made thin without being interfered with by the light incident part 12.

The light source 3 is, for example, a linear light source such as a cold cathode tube, and the light from the light source 3 is reflected by the inner surface of the reflecting member and is efficiently introduced into the light incident portion 12.

The front light A having such a structure
Then, the light from the light source 3 is introduced from the light entrance portion 12, is reflected by the prism groove 11a formed in the light exit portion 11, and is directed to the liquid crystal display plate 2, which is further reflected by the liquid crystal display plate 2 to emit light. The light is emitted from the upper surface of the portion 11. As a result, the brightness of the liquid crystal display panel 2 is improved, and a display that is easy to see is possible.

The backlight B has the same basic structure as the front light A, except that the light guide member 1 is arranged upside down, and a transmissive liquid crystal is provided above the light emitting portion 11. This is the point at which the display board 2'is arranged. In the backlight B, the light from the light source 3 is introduced from the light entrance portion 12, reflected by the prism groove 11a formed in the light exit portion 11, and emitted toward the liquid crystal display plate 2 '. As a result, the brightness of the liquid crystal display panel 2 is improved, and a display that is easy to see is possible.

As described above, the light guide member 1 of this embodiment is
It can be used for both front and back lights.

Next, a method of manufacturing such a light guide member 1 will be described. In the present embodiment, the light emitting portion 1 in which the prism groove 11a which is the light emitting pattern is formed by press working.
1 is formed, and then the light incident portion 12 is integrally molded with the light emitting portion 11.

First, the procedure for forming the light emitting portion 11 having the prism groove 11a will be described. 2A and 2B are views showing an example of forming the prism groove 11a by press working.

In FIG. 2A, the base material 110 forming the light emitting portion 11 is pressed between the pair of pressure rolls 201 and 202. The base material 110 is, for example, PMMA.
(Methacrylic resin), PC (polycarbonate resin),
It is a plate-shaped transparent substrate such as polyolefin. The pressure roll 201 has a pattern corresponding to the light emission pattern of the light emitting section 11 formed on the peripheral surface thereof. In the present embodiment, since the prism groove 11a is used as the light output pattern of the light output unit 11, a plurality of linear protrusions 201a having a shape corresponding to the prism groove 11a are provided substantially parallel to each other. The pressure roll 202 has a flat peripheral surface.

Then, the base 110 is pressed against the pressure roll 201.
When the pressure rolls 201 and 202 are rotated in the direction of the arrow in the drawing while being sandwiched while being loaded by the pressure rolls 202 and 202, the base material 110 is pressed between the pressure rolls 201 and 202, and the base roll 110 is rotated around the pressure roll 201. The protrusion 201a thus provided forms the prism groove 11a on one surface of the substrate 110. At this time, it is preferable to heat the base material 110 to soften it so that the prism grooves 11a can be smoothly moved.
Is formed and the life of the pressure rolls 201 and 202 is extended. The heater for performing such heating is a pressure roll 2
It may be provided in at least one of 01 and 202.

Substrate 110 on which prism groove 11a is formed
Is then cut into a size corresponding to the light output unit 11,
The light emitting unit 11 is created. Of course, the base material 110 may be cut in advance to a size corresponding to the light output part 11, and the prism groove 11a may be formed between the pressure rolls 201 and 202.

The formation of the light emitting pattern by this press working is different from that of the conventional injection molding in that the base material 11 is formed.
The light emitting pattern can be accurately formed on the substrate 1 regardless of the thickness of 0.
The light emitting portion 11 can be formed on the light emitting element 10, and a thinner light emitting portion 11 can be formed. As shown in FIG. 2A, the prism groove 1 is parallel to the rotation direction of the pressure roll 201.
By forming 1a, the collapse of the groove shape and the like can be suppressed to a minimum.

FIG. 2B shows pressure rolls 201 and 20.
An example in which pressure plates 301 and 302 are used instead of No. 2 is shown. On the lower surface of the pressure plate 301, a pattern corresponding to the light emitting pattern of the light emitting unit 11 is formed. In the present embodiment, since the prism groove 11a is used as the light output pattern of the light output section 11, a plurality of linear protrusions 301a having a shape corresponding to the prism groove 11a are provided substantially parallel to each other. The upper surface of the pressure plate 302 is flat.

In the case of the example shown in FIG. 2B, the pressure plate 301 is lowered while the substrate 110 is placed on the pressure plate 302, and the substrate 110 is pressed between the pressure plates 301 and 302. At this time, the protrusions 301a of the pressure plate 301 form the prism grooves 11a (not shown in FIG. 2B) on the substrate 110.

Next, the light emitting section 11 thus created
On the other hand, a procedure for integrally forming the light incident portion 12 will be described. FIGS. 3A to 3C show the light exiting portion 11 and the light entering portion 1.
It is a figure which shows the example of the method of integrally forming 2 and. Light entrance section 1
As the material of 2, for example, a thermosetting resin containing an unsaturated polyester resin, a diallyl phthalate resin or the like, or a photo-curing resin containing an acrylic ester-based resin or an unsaturated polyester resin-based resin is preferable. It is preferable to use a material having the same refractive index as or similar to that of the above material.

FIG. 3 (a) shows a case where the light entering portion 12 is prepared separately from the light emitting portion 11 and the two are joined together. As a joining method, for example, adhesion with an adhesive,
Ultrasonic welding etc. are mentioned.

FIGS. 3B and 3C show molds 401 and 4.
In this example, 02 is used to form the light incident portion 12 and the light emitting portion 11 at the same time. Molds 401 and 40
In FIG. 2, a cavity 403 corresponding to the outer shape of the light incident part 12 is formed, and a mold 401 is provided with an injection port 401a for the material forming the light incident part 12 and an air vent hole 401b.

Then, as shown in FIG. 3B, the mold 40
Openings 40 communicating with the cavities 403 of 1 and 402
With the light exiting part 11 inserted in 4, the material forming the light entering part 12 is introduced and filled into the cavity 403 from the injection port 401a. Then, when the filled material is solidified, the molds 401 and 402 are removed to complete the light guide member 1 in which the light entrance part 12 and the light exit part 11 are integrally molded.

According to such a method of manufacturing the light guide member 1, the light entrance portion 12 can adopt any shape, so that even if the light exit portion 11 is thinned, the light utilization efficiency is not lowered. The light guide member 1 can be created. Also,
Since the light incident part 12 can have any shape, for example, the following forms can also be adopted.

4A and 4B are views showing another example of the light guide member 1. FIG. 4A is an external view thereof, and FIG. 4B is a plan view thereof.
The example of FIG. 4 shows a mode in which a point light source such as an LED is adopted as the light source instead of the linear light source.
Is the same as described above.

In this example, the light incident part 120 is provided with a reflection part for reflecting the light from the point light source. In detail,
The light from the point light source is converted into parallel light like the light in the case of using the linear light source by the reflecting section, and the parallel light is made incident on the light emitting section 11.

The light entrance part 120 has a point light source 30 arranged on two opposite side surfaces thereof, and a front surface thereof has
A plurality of grooves 121 are formed.

This groove 121 is for reflecting the light from the light source 30 toward the light emitting portion 11 as shown in FIG. 4B, and in the case of this embodiment, a prism groove having a triangular cross section is adopted. is doing. The principle of reflection is the same as that of the prism groove 11a provided in the light output part 11.

By reflecting the light from the light source 30 toward the light emitting portion 11 by such a groove 121, the same light emission as in the case of using the linear light source while using the point light source 30 is performed. . In addition, in this example, the light entering portion 1
It is efficient to convert the point light source into the linear light source more effectively by arranging the light source unit 20 and the light emitting unit 11 so as to be bonded to each other with a slight gap therebetween.

FIG. 5 is an external view showing still another example of the light guide member 1. The example of FIG. 5 also shows a mode in which a point light source such as an LED is adopted as the light source instead of the linear light source, and the light emitting unit 11 is the same as that described above.

In this example, the light entrance portion 220 employs a microlens instead of the groove 121 described above. A plurality of microlenses 221 are provided on the front surface of the light incident part 220, and the point-shaped light source 31 is arranged to face the microlenses 221. In this example, the microlens 221 has a semicircular cross section and is provided in a semicircular columnar shape extending in the vertical direction. Although the microlens 221 in this example has such a structure, various modes can be selected for the shape and arrangement.

By providing such a microlens 221, the light incident from the light source 31 to the light incident portion 220 is dispersed and incident, and the light distribution in the light emitting portion 11 is made uniform.

[0040]

As described above, according to the present invention,
It is possible to reduce the thickness of the light guide member while maintaining the utilization efficiency of the light from the light source.

[Brief description of drawings]

FIG. 1A is a sectional view showing the structure of a front light A using a light guide member 1 according to an embodiment of the present invention,
(B) is a cross-sectional view showing a structure of a backlight B using the light guide member 1.

2A and 2B are views showing an example of forming a prism groove 11a by press working.

3A to 3C show a light emitting section 11 and a light entering section 12;
It is a figure which shows the example of the method of integrally forming and.

4A is an external view of another light guide member 1, and FIG. 4B is a plan view thereof.

FIG. 5 is a diagram showing an external view of still another light guide member 1.

[Explanation of symbols]

A front light B backlight 1 Light guide member 11 Idemitsu 11a Prism groove (light emission pattern) 12 Light incident part 201, 202 Pressure roll 110 base material 401, 402 type

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/13357 G02F 1/13357 // B29L 11:00 B29L 11:00 F21Y 101: 02 F21Y 101: 02 F Term (reference) 2H038 AA52 AA55 BA06 2H091 FA23X FA23Z FA41X FA41Z FB02 KA10 LA11 LA16 4F209 AA36 AA44 AC03 AF01 AG01 AG05 AH73 AH77 PA01 PA02 PA04 PB02 PC01 PH06 PN06 PW23

Claims (7)

[Claims] 1. A method of manufacturing a light guide member having a light emitting part and a light entering part, the method comprising: forming the light emitting pattern by forming a light emitting pattern on a base material by press working; A method of manufacturing a light guide member, comprising: an integrally forming step of integrally forming the light incident portion on the light emitting portion. 2. The conductive member according to claim 1, wherein, in the integrally forming step, the light incident portion, which is formed separately from the light emitting portion, is integrally molded by joining the light incident portion to the light emitting portion. Optical member manufacturing method. 3. In the integrally forming step, the light exiting part is placed in a predetermined mold having a part forming the light entering part, and a material forming the light entering part is introduced into the part and solidified. The light guide member manufacturing method according to claim 1, wherein the both are integrally formed. 4. The light entrance part has a light source side end part which is arranged to face the light source, and the thickness of the end part is thicker than the thickness of the light exit part. A method for manufacturing the light guide member described. 5. The method for manufacturing a light guide member according to claim 1, wherein the material forming the light incident portion is a photocurable resin or a thermosetting resin. 6. A light guide member having a light exiting part and a light entering part, wherein the light entering part is integrally formed with the light exiting part formed by forming a light exiting pattern on a base material by press working. A light guide member made of. 7. A light guide member having a light exit portion and a light entrance portion, wherein the light entrance portion is integrally formed with the substantially plate-shaped light exit portion on which a light exit pattern is formed. The light guide member is characterized in that the portion has a light source side end portion which is arranged to face the light source, and the thickness of the end portion is thicker than the thickness of the light emitting portion.