JPS6190584A - Projection-type display device - Google Patents

Abstract

PURPOSE:To improve the utilization factor of light from a light source by converting one polarizing surface among an S polarizing component Lintegral and P polarizing component LP, both of which are obtained from a polarizing beam splitter, into the other polarizing surface with the use of a lambda/2 optical phase plate and setting their synthetic light beams to the illumination light of a light valve. CONSTITUTION:A total reflection prism 18 is disposed at the side where the P polarizing component of the polarizing beam splitter 7 is obtained through the reflection. The P polarizing component LP is reflected orthogonally against the total reflection prism 18 and projected in the same direction as the S polarizing component LS obtained by passing through the polarizing beam splitter 7. Light paths of the S polarizing component LS obtained in such a way and the S polarizing component LS* converted by the lambda/2 optical phase plate 19 are changed in each optical path, and synthesized so as to coincide at the prescribed position P0. The synthetic light of the S polarizing components LS and LS* is made flux having a narrow band-like flattening section extending in the horizontal direction with the aid of a semicylindrical lens 8, and supplied to a line right valve 10 as illumination light.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a projection type display device using a light valve. [Prior Art] As a projection type display device, a line light valve as shown in FIG. A device using this has been proposed.

In the figure, (1) is a light source which has a light emitting part (2) and a reflector (3). The light emitting unit (2) K is, for example, a medium senon arc lamp, and the reflector (3) is configured to reflect visible light and allow heat rays to pass through.

The light from the light source (1) passes through a heat ray reflection plate (4) that reflects heat rays and passes visible light, and then passes through a condenser lens, l"
(5) and is made into a parallel light beam. The light from this condenser lens (5) passes through an aperture plate (6) and is supplied to a polarizing beam splitter (7) that constitutes a polarizer, and only polarized light having a predetermined plane of polarization, that is, S-polarized light Ls passes through. It can be obtained by The polarized light from this polarizing beam splitter (7) is supplied to a kamabob-shaped lens (8), and after being made into a light beam having a strip-shaped polarization cross section extending in the horizontal direction,
Line light bulb αQ supported by transparent support plate (9)
is supplied as illumination light. This line light bulb α
0 is made of, for example, PLZT electro-optic ceramic material,
It is formed by 512 light valves, and is a kama? The plane of polarization is rotated by a predetermined angle in each light valve part for the light beam with a narrow strip-like flat cross section supplied from the U-shaped lens (8).The plane of polarization is rotated by a predetermined angle in this line light valve (10). The emitted light passes through the reduction lens α, has its optical path changed by the movable mirror (6) that deflects and scans in the vertical direction, and then passes through the field lens 0 and enters the polarizing beam switcher α that constitutes the analyzer. The light is supplied to the line light valve αQ and is allowed to pass by an amount corresponding to the rotation angle of the plane of polarization in the line light valve αQ.

The light from the polarizing beam splitter α→ is projected onto a screen (not shown) K by the projection lens α valley.

1. In FIG. 6, aQ is a control circuit section, and its input terminal (16a) K is supplied with a video signal S. The 512 light valves of the line light valve αQ are sequentially driven by sample signals at 512 points within the horizontal period of the video signal Sv, and each light valve portion rotates the plane of polarization by an angle corresponding to the signal content. The video signal Sv
is controlled in synchronization with the horizontal period of

In addition, the mirror drive unit α is controlled, and the movable mirror (2)
performs a deflection scanning operation in synchronization with the vertical period of the video signal SV.

From the above configuration, according to the display device shown in FIG. 6, an image based on the video signal Sv can be obtained on the screen. [Problems to be solved by the invention] The display device shown in FIG. In the gray device, of the light from the light source (1), only the S-polarized component L8 obtained by passing through the polarizing beam splitter (7) is used as illumination light, and the S-polarized component of the light from the light source (1) The P-polarized light component having a plane of polarization perpendicular to L8 is reflected by the polarizing beam splitter (7) and is not used as illumination light. Therefore, the display device shown in FIG. 6 has a disadvantage that the utilization rate of light from the light source (1) is as low as 50% or less.

Therefore, the present invention aims to improve the utilization efficiency of light from a light source. [Means for solving the problems] In order to solve the above-mentioned problems, the present invention aims to improve the utilization efficiency of light from a light source. One polarization plane of the S-polarized component and one P-polarized component is converted into the other polarization plane using an optical phase plate, and the combined light is used as illumination light for a light valve.

[Operation] 5. Since both the S-polarized light component L8 and the P-polarized light component LP obtained from the polarizing beam splitter are used as illumination light, the utilization rate of light from the light source is improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. This example is applied to a display device using a light bulb as shown in FIG. In FIG. 1, parts corresponding to those in FIG. 6 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 1 is a view seen from the vertical direction. In the figure, a total reflection prism α→ is arranged on the side of the polarization beam splitter (7) where the P polarization component is reflected, and the P polarization components t and p are reflected at right angles at the zero peak of this total reflection prism. hand,
It is used in the same direction as the three-polarized component L8 obtained by passing through the polarizing beam splitter (7).

λ There is still an optical phase plate (
), and the P-polarized light component LP emitted from the total reflection grism α peak has its polarization plane rotated by 90 degrees by the optical phase plate (2), and is converted into the S-polarized light component L8.

In addition, a polarizing beam splitter (7) and a main optical phase plate (
2) are provided with a wedge-shaped lens (prism) for changing the optical path and a Q force, respectively, and the S polarized light components L8 and I obtained by passing through the polarizing beam
The S-polarized light components L: converted by the optical phase plate (2) have their respective optical paths changed and are combined so as to match at a predetermined position P0.゛Also, the line light valve αQ is disposed in front of the predetermined rectangular position P0, and furthermore, a kamagob-shaped lens (8) is disposed in front of this line light valve←Q. Then, the S-polarized component and the combined light of L8 are transmitted through a kamagob-shaped lens (8
) is converted into a light beam having a narrow strip-like flat cross section extending in the horizontal direction, and is supplied to the line light valve u1 as illumination light.Although not directly related to the present invention, in this example, the control circuit unit 0Q is configured, for example, as shown in FIG. In FIG. 2, parts corresponding to those in FIG. 1 are designated by the same reference numerals.

In FIG. 2, the video signal SV supplied to the input terminal (16a) is supplied to the synchronization separation circuit via the video amplification circuit (A). The vertical synchronization signal Pv obtained by this synchronization separation circuit) is supplied to a deflection control circuit (c), which controls the mirror driving part α force, ) is configured to perform a seven-deflection scanning operation in synchronization with the incense period of the video signal SV.

In addition, the horizontal synchronization signal P obtained from the synchronization separation circuit is supplied to the oscillator (c) as a reference signal, and this oscillator (c)
From c), a frequency signal of, for example, 1024fa (fH is the horizontal frequency) is obtained, and this is supplied to the sample pulse generator (c). And a sangur pulse generator (c)
is provided with 64 output terminals OH* (hr...064, and these respective output terminals 01 + Ox *...
・From l064, sample pulse SPI at the timing of the end of each horizontal period (IH) divided into 64 periods
tSF3s...

5P64 (illustrated in FIG. 3B) is obtained. Incidentally, FIG. 3A shows the horizontal synchronization signal PR.

Further, in FIG. 2, the video signal SV obtained from the video amplification circuit (a) is supplied to the delay line through the r correction circuit and the delay circuit for time adjustment. This delay line - is provided with eight tags pt l PZ +...+P8, and the current signal of the video signal Sv is obtained from the tag ps, and the taps P7 + Pg *..., pl[ are The signals of the previous completed horizontal period (512H) are sequentially obtained. Tara f PH+ P2+...+PB are respective amplifiers (
30t).

(302), .
As shown in FIG. 4, 512 light valves 4 +
Light valve zt of line light valve α1 consisting of 12 +...+ zstz #4 +...lt.

is supplied to the signal electrode. Also, an amplifier (301).

The signals obtained from (30g), =, (30a) are transmitted through the light valve ze l 4o l... through the drain-source of FETs + TH) +...+ Tta, respectively.
, is supplied to the signal electrode of t16, and then □7 in a downward direction.
:/7″(301), C30z),・”, (
The signals obtained from 30g) are sequentially supplied to the signal electrodes of the eight light valves of line light valve four.

Further, the sample pulse sp1 obtained at the output terminal 01 of the sample pulse generator (1) is generated by the FET Tl? T
2 +..., supplied to the date of T8, these FETs
Tl*T21...+T8 are turned on at the timing of this sample pulse SPi. In addition, the sample current SP obtained at the output terminal 02 is the FET T
g 1T1o l "" r T16 pace, these FETs Tg r Tso y "・e T
ts is turned on at the timing of this sample signal SP2, and the output terminals 03 r 04 +...
・Sample pulse SP3 * SP obtained at o64
a+...l 5P64 is supplied to e-) of each of the 8 FETs, and each of the 8 FETs receives a sample pulse SP3! SF3 *...

SF3. It is turned on at the timing of

Therefore, light valve 4 + Z2+ of line light valve α0
...The signal electrode of l ta is FET Tt r T
2 +...+Ts, among the horizontal period signals of the video signal SV, the sample pulses 5Pttf (7) π of the horizontal period signals of the video signal SV are extracted from the horizontal synchronization signal PH to the eight sample signals S2' r S2 # included in the π horizontal period (πH), respectively. ..., S8 is supplied. In addition, light valve 4 p of line light valve αQ
tlo +..., t16 signal electrodes are equipped with FETs.
To * Tto * -a Sample pulse SP of each horizontal period signal of the video signal Sv through Tts, respectively.
Eight sample signals so l sio l..., S16 included in the π horizontal period from l to SF3 are supplied, and thereafter in the same manner, the i valve 4y+ of the line light valve α0
411 +...l'! The sample signal s17°S18. ...l 5stz is supplied. The line light valves (10 512 light valves zt l t2 *...ts12 are driven by signals 81*s, e...t 5stz, respectively).

According to the control circuit unit aQ configured in this way, each light valve zt l 12 * of line light valve<10
”・.

ts1! Since eight signals to the signal electrodes are sampled in parallel, the sampling frequency can be lowered compared to the sequential sampling method, and for example, the number of shift register stages of the sample pulse generator (c) consisting of shift registers can be significantly reduced. The number of parts and power consumption can be significantly reduced. Also, Tara 7°PI r PZ *
..., P8 is used to sequentially supply digital signals (1, 01) to each light valve 4 + t of the line light valve uQ.
2*...11611 can be easily driven with a digital signal.

According to this example configured as shown in FIG. 1, the S-polarized light component obtained from the polarizing beam splitter.

Both P polarization and light component LP are line light valves O.
Since it is used as the illumination light of Q, the utilization rate of the light from the light source (1) is improved. Furthermore, as in this example, by arranging the line light valve α0 in front of the predetermined position P0, the illumination of the line light valve α0, which has an extremely large aspect ratio, is covered by the cooperation of the S-polarized light components L8 and Ls*. Therefore, the diameter of the original illumination can be made small, and therefore, a polarizing beam splitter (7) etc. with small dimensions can be used, and there is an advantage that it can be constructed at a low cost. In addition, in the case of this example, since the S-polarized components Ls and Ls* are subject to internal refraction, by setting the wedge-shaped lens (c), the predetermined position P0 is moved to the reduction lens (Ill (see Figure 6)). By setting it at the center of the entrance pupil, it is effective to have a field lens effect.

Next, FIG. 5 shows another embodiment of the present invention,
Components corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In the example shown in FIG. 5, an optical phase plate 0 is arranged in front of the wedge-shaped lens ηλ, and the S-polarized light component LH obtained by passing through the polarizing beam splitter (7) and the optical phase plate in this area are The plane of polarization is rotated by 45 degrees from zero.

The rest of the structure is the same as the example shown in FIG.

By rotating the polarization planes of the S-polarized light components L8 and L8 by 45 degrees as shown in the example in Fig. 5, these polarization planes form an angle of 45 degrees with the electric field applied to each light valve of the line light valve α0. Therefore, the maximum polarization sensitivity can be obtained in the line light valve α1.

In the above-mentioned embodiments, a transmissive type light valve in which light passes through the line light valve αQ is shown, but it can be similarly applied to a reflective type in which light is reflected from the line light valve αQ. Further, although the above-mentioned embodiment uses a line light valve αQ, the present invention can be similarly applied to those using a two-dimensional light valve. Further, in the above embodiment, the polarization plane of the P-polarized light component LP obtained from the polarized beam splitter (7) is rotated by 90 degrees to form a composite light of the S-polarized light component. ) It is also possible to rotate the polarization plane of the S-polarized light component L8 obtained by 90 degrees and use it as a composite light of the P-polarized light component. Furthermore, in the above embodiment, the total reflection prism α
A mirror may be used instead of →.

〔Effect of the invention〕

According to the present invention described above, since both the S-polarized light component L8 and the P-polarized light component LP obtained from the polarizing beam splitter are used as illumination light for the light valve, the utilization rate of light from the light source is improved. Therefore, if the same light source as before is used, it is possible to obtain an even higher brightness image on the screen.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a specific block diagram of a control circuit section, FIGS. 3 and 4 are diagrams for explaining the same, and FIG. A block diagram showing another embodiment, and FIG. 6 is a block diagram showing a conventional example. (1) is a light source, (7) is a polarizing beam splitter, (8)
Kama? U-shaped lens, <11 is line light bulb, α
υ is total reflection! Rhythm, (to) and 0η are respectively optical phase plates, and cylindrical lenses and 0η are wedge-shaped lenses, respectively. Procedural amendment written in 1982 Patent Application No. 211843 3, Relationship with the case of the person making the amendment Patent applicant address 6-7-35, Kitashinyo, Tokyo Parts Co., Ltd. Name (2)
18) Sony Corporation Representative Director Norio Ohga 4, Agent Address: 1-8-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo 03-
343-5821tl cut (Shinjuku Building) 6. Number of inventions increasing due to correction 1 (1
) In the specification, page 2, page 11, page 4, line 7, line 8, page 5, line 19, page 6, line 3, line 7, line 8, line 14, line 11
Page 10, line 14, page 12, line 4, line 5, line 8, page 13
Page 3 and 4 lines rsJ are corrected to rPJ. (2) Same, page 2, line 11, page 4, line 7, line 1.8, page 5, line 19, page 6, line 7, line 14, page 11, line 10, 1
Line 4, page 12, line 4, line 8 and page 12, line 4 rLs J
Correct the text to rt and p J. (3) - Add "corresponding to the video signal" before "predetermined angle" on page 2, line 20. (4) Same, page 4 line 9, page 5 lines 15 and 17, page 6 line 2, page 13 line 2 and 5 r'P'J
Correct each to SJ. (5) In the same document, the words rL and pJ are corrected to rLsJ in line 9 on page 4, line 17 on page 5, line 2 on page 6, and line 2 on page 13. (6) Same, page 4, line 10, "reflected" is corrected to "reflected at 45 degrees." (7) Same, page 6 lines 3, 8, and 14, page 11 lines 10 and 14, page 12 lines 5 and 8 r
Correct each to Lp town. (8) In the drawings, Figures 1, 6, and 6 are corrected as shown in the attached sheets. that's all

Claims (1)

[Claims] In a projection display device using a light valve, light from a light source is supplied to a polarizing beam splitter to obtain a first S-polarized light component and a first P-polarized light component, and the first S-polarized light component or the first P-polarized light component is The P-polarized light component of is converted into a second P-polarized light component or a second S-polarized light component by a λ/2 optical phase plate, and a composite light of the first and second S-polarized light components or a composite light of the first and second S-polarized light components is generated. A projection type display device characterized in that the combined light of the P-polarized light component is used as the illumination light of the light valve.