JP3428189B2 - Light source device for liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display which has improved light utilization efficiency, high brightness, and improved cooling performance.
The present invention relates to an indicating light source device .

[0002]

2. Description of the Related Art Recently, a display device such as a projector device using an optical element such as a liquid crystal panel, a television receiver, and a display for a computer has been widely used. For example, a liquid crystal display device using a liquid crystal panel or the like causes light emitted from a light source such as a metal halide lamp or a halogen lamp to enter a liquid crystal panel having color filters (R, G, B), thereby A color image can be obtained as output light. Then, the output light from the liquid crystal panel is projected on the screen by the projection lens.

By the way, light emitted from an ordinary light source has two planes of polarization which are orthogonal to each other, and these planes of polarization are generally P-polarized component (hereinafter referred to as P-wave) and S-polarized component (hereinafter referred to as P-polarized component). , S wave). Further, in the liquid crystal display device as described above, the polarization means is arranged before the light emitted from the light source is incident on the liquid crystal panel, and the P-wave is generated corresponding to the polarizing plate provided on the front surface of the liquid crystal panel. Light having a polarization plane of either S wave or S wave is emitted.

5 (a) and 5 (b) are views showing an example of a conventional polarization means, FIG. 5 (a) is a perspective view, and FIG. 5 (b) is a view explaining an optical path. In these figures, 20 indicates the entire optical block. The optical block 20 is configured by laminating a plurality of glass prisms 20a to 20f, for example. 22 and 22 are prisms 20b,
Polarization Beamsplitters provided between 20c and between prisms 20d and 20e.
(Hereinafter referred to as PBS), 23 and 23 are prisms 20
The wave plate provided in front of a and 20f is shown.

Next, the optical block 2 according to FIG.
The optical path of 0 will be described. In this figure, reference numeral 11 denotes a light source, and the light beam emitted from the light source 11 passes through the optical block 20 so that, for example, only the P wave enters the liquid crystal panel (not shown). That is, the P + S wave emitted from the light source 11 is indicated by a black arrow and the optical block 2.
The optical path of the P wave split by 0 is shown by a white arrow, and the optical path of the S wave is shown by a shaded arrow.

First, the P + S wave incident from the light source 11 is P
The BS waves are dispersed by the BSs 22 and 22, and the P wave is transmitted as it is and is incident on the liquid crystal panel. The S wave is reflected by the PBSs 22 and 22, and then is reflected forward by the prisms 20a and 20f, and is converted into P wave by the wave plates 23 and 23 and is incident on the liquid crystal panel. That is, only the P wave is emitted from the front surface portions of the prisms 20c and 20d and the wave plates 23 and 23. In this way, of the S + P waves emitted from the light source 11, only the light of one of the polarization components is made incident on the liquid crystal panel (not shown) by the optical block 20.

[0007]

However, the optical block 20 including the prisms 20a to 20f as described above is used.
Is required, a thickness of 45 ° is required with respect to the front surface portion, and the width of the front surface portion is about 2 times that of the emission port of the light source 11.
Since it is nearly doubled, the overall size will also increase.
In addition, the optical block 20 includes a glass prism 20a to
Since it is made of 20f, it has a considerable weight and is expensive because it requires high transparency and homogeneity. Further, as a cooling means for the optical block 20, for example, a cooling fan or the like needs to be individually provided, and there is a problem that a space for disposing the cooling means must be secured.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an internal opening formed with an entrance through which light from a light source enters and an exit corresponding to the entrance. Consists of a container filled with a liquid having a refractive index almost equal to the refractive index of glass, in the container, arranged in a V shape toward the front, the first incident from the light source,
A first polarization beam splitter that reflects only the light of the second polarization component of the second polarization component in a predetermined direction, and a light of the second polarization component that is reflected by the first polarization beam splitter And a wavelength plate that polarizes the light of the polarization component of, and is arranged in a V-shape outside the wavelength plate toward the front, and only the light of the second polarization component that is incident from the light source and the wavelength plate has a predetermined direction. A second polarization beam splitter which is reflected in the direction of the second polarization beam splitter, and is arranged in a V-shape outside the second polarization beam splitter toward the front, and forwards the light reflected and transmitted by the second polarization beam splitter. and a total reflection mirror for reflecting, in a liquid crystal display light source device example Bei a polarizing plate that transmits only light of the first polarized light component reflected by the total reflection mirror.

The container is provided with an entrance through which the light of the light source enters and an exit corresponding to the entrance, and the inside of which is filled with a liquid having a refractive index substantially equal to that of glass.
In the container, arranged in a V shape toward the front,
First polarization beam splitter that reflects only the light of the second polarization component of the first and second polarization components incident from the light source in a predetermined direction, and forward to the outside of the first polarization beam splitter. A second polarization beam splitter arranged in a V shape toward the second polarization beam splitter that reflects only the light of the second polarization component incident from the light source and the first polarization beam splitter in a predetermined direction; and the second polarization beam splitter. A polarizing plate that blocks the light of the second polarization component reflected by the beam splitter, and is arranged outside the second polarization beam splitter in a V shape toward the front, and is reflected by the second polarization beam splitter. And a total reflection mirror that reflects the transmitted light forward,
A light source for a liquid crystal display , characterized in that a wavelength plate arranged so as to polarize the light of the second polarization component reflected by the total reflection mirror into the light of the first polarization component is mounted.
Configure the device .

A third polarization beam splitter is provided between the second polarization beam splitter and the mirror to reflect only the light of the second polarization component incident from the second polarization beam splitter in a predetermined direction. , A liquid crystal in which the second wave plate is arranged so as to polarize the light of the second polarization component reflected by the third polarization beam splitter into the light of the first polarization component.
A display light source device is configured.

[0011]

According to the present invention, the liquid crystal display light source device is downsized,
In addition, light can be effectively used while achieving weight reduction, and by disposing PBS in the liquid, it is possible to have a cooling function.

[0012]

EXAMPLES Examples of the liquid crystal display light source device of the present invention will be described below. FIG. 1 is a diagram showing an outline of a liquid crystal projector device using a light source device for liquid crystal display of the present invention. In this figure, reference numeral 1 denotes a container constituting a light source device, which is made of, for example, metal, in which a PBS, a wave plate, a polarizing plate, a mirror, etc., which will be described later, are arranged and filled with a liquid having a refractive index equivalent to that of glass. Has been done. 2 is a lid for sealing the container 1 3
Reference symbol a denotes an emission port formed of a transparent plate in front of the container 1, and a predetermined polarization component (P wave in this embodiment) of light incident from the light source 11 is emitted. Incidentally, as shown in FIG. 2 later, an entrance 3b is formed on the opposite side of the exit 3a to allow the light emitted from the light source 11 to enter.

Reference numeral 9 denotes a liquid crystal panel on which light emitted from the light source device for liquid crystal display is incident and which forms an image by a predetermined drive signal. In this embodiment, a polarizing plate corresponding to P waves is provided on the front side. It is assumed that Reference numeral 10 denotes a lens for enlarging and projecting an image formed by the liquid crystal panel 9.

Next, a first embodiment of the liquid crystal display light source device shown in FIG. 1 will be described with reference to FIGS. 2 (a) and 2 (b). FIG. 1A is a perspective view showing the inside by cutting out a part of the front surface of the container 1, and FIG. 1B is a view for explaining the optical path of the liquid crystal display light source device . In these figures, 3b is an entrance port formed on the opposite side of the exit port 3a described above, 4a, 4
PBSs (Polarizing Beam splitters) a, 4b, and 4b are arranged in a V shape at a predetermined angle toward the front.
) Is shown. Each of these PBSs 4a and 4b is formed by attaching an optical thin film to a plate glass, for example, and in this embodiment, it reflects the S wave of the light incident from the light source 11 and transmits the P wave.

Reference numerals 5 and 5 are wave plates arranged between the PSBs 4a and 4b, 6 is a total reflection mirror arranged outside the PBS 4b in a V shape, and 7 and 7 are reflected by the total reflection mirrors 6 and 6. A polarizing plate that transmits only a specific polarization component (P wave in this embodiment) of the light is shown. In this embodiment, only P wave is transmitted. Reference numeral 8 denotes a liquid filled in the container 1, which is a liquid having a refractive index almost equal to that of glass (for example, n = 1.43), and for example, a mixed solution of ethylene glycol and glycerin is used. . Therefore, the PBSs 4 a, 4 b, the wave plate 5, the total reflection mirror 6, and the polarizing plate 7 are arranged in the liquid 8 in the container 1.

[0016] Next follows the FIG (b), the liquid in this embodiment
The optical path of the crystal display light source device will be described. First, the P + S wave incident from the central portion of the light source 11 is split into P wave and S wave by the PBS 4a or 4b arranged in a V shape at an angle of about 45 °. The P wave transmitted through the PBS 4a is directly emitted from the emission port 3a to the liquid crystal panel 9 not shown in this figure. On the other hand, the S wave reflected by the PBS 4a is polarized by the wave plate 5 so that the polarization component becomes the P wave, passes through the PBS 4b, and is reflected forward by the total reflection mirror 6. Then, the light passes through the polarizing plate 7 and is emitted to the liquid crystal panel 9 from the emission port 3a.

The P-wave incident on the PBS 4b from the peripheral portion of the light source 11 is also transmitted through the PBS 4b as it is, and the emission port 3a is formed.
To the liquid crystal panel 9. Further, the S wave reflected by the PBS 4b is further reflected by the total reflection mirror 6 and enters the polarizing plate 7. However, since the polarizing plate 7 is designed to transmit only the P wave as described above, the S wave is blocked here. This is provided to prevent the polarizing plate of the liquid crystal panel 9 from absorbing heat of S wave because the polarizing plate of the liquid crystal panel 9 corresponds to P wave.

The container 1 containing the liquid 8 in this way
By disposing optical elements such as the PBSs 4a, 4b, the wave plate 5, the total reflection mirror 6, and the polarizing plate 7 which are smaller in size than the irradiation opening of the light source 11 at a predetermined angle, The size and weight can be reduced, and the emission port 3a can also be configured to have, for example, about 1.5 times the diameter of the light source 11. Further, since each of the optical members is arranged in the liquid 8, the liquid 8 absorbs the heat of each component, so that the temperature rise can be prevented. Therefore, it is not necessary to separately provide a cooling means, and it is possible to save space.

3A and 3B are views showing a second embodiment of the liquid crystal display light source device , and the same parts as those in FIG. 2 are designated by the same reference numerals. In this embodiment, the wave plates 5 and 5 are arranged in front of the total reflection mirror 6, and the polarizing plates 7 and 7 are PBs.
It is arranged in front of S4b.

The P + S wave incident from the central portion of the light source 11 is split into P wave and S wave by the PBS 4a or 4b. P
The P wave transmitted through the BS 4a is directly emitted from the emission port 3a to the liquid crystal panel 9. On the other hand, the S wave reflected by the PBS 4a is reflected by the PBS 4b and blocked by the polarizing plate 7. This is to prevent heat generation of the liquid crystal panel 9 as in the case described above.

Further, the P wave incident on the PBS 4b from the peripheral portion of the light source 11 is transmitted through the PBS 4b as it is, and the exit port 3 is formed.
The light is emitted from a to the liquid crystal panel 9. Further, the S wave reflected by the PBS 4b is reflected by the total reflection mirror 6, enters the wave plate 5, and is polarized so that its polarization component becomes the P wave, and is emitted to the liquid crystal panel 9.

FIGS. 4A and 4B are views showing a third embodiment of the liquid crystal display light source device , and the same parts as those in FIG. 2 are designated by the same reference numerals. Further, in this embodiment, PBS 4b,
Third PBSs 4c and 4c are arranged outside 4b. The polarizing plates 7 and 7 are arranged in front of the total reflection mirrors 6 and 6, and wave plates 5 and 5 are added in front of the PBSs 4c and 4c. 2A and 2B, the wave plate described in FIG. 2 will be described as 5a, and the wave plates added in this embodiment will be described as 5b and 5b.

The P + S wave incident from the central portion of the light source 11 is split into P wave and S wave by the PBS 4a or 4b. P
The P wave transmitted through the BS 4a is directly emitted from the emission port 3a to the liquid crystal panel 9. On the other hand, the S wave reflected by the PBS 4a is polarized by the wave plate 5a so that the polarization component becomes the P wave, passes through the PBS 4b and the PBS 4c, and is reflected by the total reflection mirror 6. Then, the light is transmitted through the polarizing plate 7 and the emission port 3
The light is emitted from a to the liquid crystal panel 9.

In addition, P incident on the PBS 4b from the light source 11
The wave passes through the PBS 4b as it is and is emitted to the liquid crystal panel 9 from the emission port 3a. In addition, S reflected by PBS4b
The wave is reflected by the PBS 4c and enters the wave plate 5b. Then, by passing through the wave plate 5b, the polarization component is polarized so as to be a P wave and is emitted.

The arrangement angles of the PBS 4 (a, b, c), the wave plate 5 (a, b), the total reflection mirror 6, and the polarizing plate 7 described in the first to third embodiments are as follows. It can be changed by filling the inside with the refractive index of the liquid 8 having a different refractive index.

[0026]

As described above, the liquid crystal display of the present invention.
The light source device for use has an optical element having a size smaller than the irradiation opening of the input light source, for example, a PBS, a wave plate, a total reflection mirror, a polarizing plate, etc., arranged at a predetermined angle in the container, and is almost equivalent to glass. Since the liquid having a refractive index is filled, the dimensions such as thickness and width can be formed to be small, space saving and weight reduction can be realized, and the cost can be reduced.
Since the arrangement angle of each component can be changed by changing the refractive index of the liquid, it is possible to easily configure light source devices of different sizes. Furthermore, since the intensity distribution of the light emitted to the liquid crystal panel can be made uniform, it is possible to improve the light utilization efficiency. Further, there is an advantage that a cooling effect can be obtained by immersing each component such as PBS in a liquid, and it is not necessary to provide a cooling means individually.

[Brief description of drawings]

FIG. 1 is a diagram showing a liquid crystal projector using a liquid crystal display light source device according to an embodiment of the invention.

FIG. 2 is a diagram showing a configuration and an optical path of a light source device for liquid crystal display of a first embodiment.

FIG. 3 is a diagram showing a configuration and an optical path of a light source device for liquid crystal display of a second embodiment.

FIG. 4 is a diagram showing a configuration and an optical path of a light source device for liquid crystal display of a third embodiment.

FIG. 5 is a diagram showing a configuration and a light path of a conventional liquid crystal display light source device .

[Explanation of symbols]

1 container 2 lid 3a exit port 3b entrance 4a, 4b, 4c, 4d PBS 5, 5a, 5b Wave plate 6 Total reflection mirror 7 Polarizer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Yamaguchi 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (56) References JP-A-5-241103 (JP, A) JP-A 5-203894 (JP, A) JP-A-5-22734 (JP, A) JP-A-4-320202 (JP, A) JP-A-7-225379 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/13357 F21V 8/00

Claims (3)

(57) [Claims] 1. A container provided with an entrance through which light from a light source is incident and an exit corresponding to the entrance and having a liquid filled therein with a refractive index substantially equal to that of glass, In the container, arranged in a V shape toward the front,
A first polarization beam splitter that reflects only the light of the second polarization component of the first and second polarization components incident from the light source in a predetermined direction, and the second polarization beam splitter that reflects the light by the first polarization beam splitter. A wavelength plate that polarizes the light of the polarization component of 1 to the light of the first polarization component, and a second polarization that is arranged in a V-shape outside the wavelength plate toward the front and that is incident from the light source and the wavelength plate. A second polarization beam splitter that reflects only the component light in a predetermined direction, and is arranged in a V shape outside the second polarization beam splitter toward the front, and is reflected by the second polarization beam splitter. And a total reflection mirror for reflecting the transmitted light forward, and a polarizing plate for transmitting only the light of the first polarization component reflected by the total reflection mirror.
Light source device for liquid crystal display . 2. A container having an entrance through which light from a light source enters and an exit corresponding to the entrance and having a liquid filled therein with a refractive index substantially equal to that of glass, In the container, arranged in a V shape toward the front,
A first polarization beam splitter that reflects only the light of the second polarization component of the first and second polarization components incident from the light source in a predetermined direction, and forward of the first polarization beam splitter outside the first polarization beam splitter. A second polarization beam splitter which is arranged in a V shape toward and which reflects only the light of the second polarization component incident from the light source and the first polarization beam splitter in a predetermined direction, and the second polarization beam splitter. A polarizing plate that blocks the light of the second polarization component reflected by the beam splitter, and is arranged outside the second polarization beam splitter in a V shape toward the front, and is reflected by the second polarization beam splitter. And a total reflection mirror that reflects the transmitted light forward, and a wave plate arranged to polarize the light of the second polarization component reflected by the total reflection mirror into the light of the first polarization component. Is installed Light source for liquid crystal display characterized by
Equipment . 3. A third polarized light which reflects only a light of a second polarized light component incident from the second polarized light beam splitter in a predetermined direction between the second polarized light beam splitter and the total reflection mirror. A beam splitter is arranged, and the second wave plate is arranged so as to polarize the light of the second polarization component reflected by the third polarization beam splitter into the light of the first polarization component. The liquid crystal table according to claim 1.
Indicative light source device .