JPH01238688A - Projection type display device - Google Patents

Abstract

PURPOSE:To form a high quality bright color image by obtaining a projective image by light modulating an image displayed on a liquid crystal panel, using a projected light which changes color sequentially after each period of a specified time. CONSTITUTION:White light which made incident through a condenser lens from a lamp is made incident on the liquid crystal panel 10A sequentially through filter parts 12A-12C of the circular filter 12 which rotates; R, G, B, R.... An image signal fed here to an image amplifier circuit 8 is fed responding to one of R, G, or B for each field. Then responding to the image for one field displayed on the panel 10A, a composite image signal from a circuit 8 is fed to a synchronizing separator circuit 13, and a vertical cynchronizing signal which has been synchronizing separated is fed to a motor driven circuit 14, making a center axis 12D of the filter 12 supported by a motor 15 rotate by 1/3 during the displaying period of one field of the image on the panel 10A. Resulting from the synchronization of this movement, a bright color image can be obtained on the exiting side of the panel 10A.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a projection type projector using a light valve that obtains an enlarged projected image by transmitting light emitted from a light source in accordance with an image signal to be enlarged and projected. Related to display devices.

(Prior Art) FIG. 4 is a block diagram of a general projection display device.

As shown in the figure, the projection type display device is configured as follows. Light emitted from a lamp 1 made of halogen or xenon is condensed and reflected by a concave mirror 2, then enters a condenser lens 3, where the light from the lamp 1 is aligned, and then a light control unit 4 having a light valve The image is displayed on the light valve and transmitted through the projection lens 5 and the aperture 6.
The image is enlarged and projected onto the screen 7 via the .

Now, a liquid crystal panel is used for the light valve that constitutes the light control section 4. Image display by this liquid crystal panel is broadly classified into matrix electrode address display and beam address display.

In the case of matrix electrode addressing display, for example, striped signal electrodes and scanning electrodes are formed on a substrate so as to be orthogonal to each other, and by time-division driving, direct,
There are two types: a simple multiplex type that displays images by driving a liquid crystal panel, and an active matrix type that displays images using a liquid crystal panel with a structure in which liquid crystal is sandwiched between two substrates on which a switching array, which is an active element, is formed. There is something.

FIG. 5 shows a light control unit 4 used in a conventional projection display device.
Fig. 1 shows the configuration of .

In the same figure, the input video signal t corresponds to the image to be displayed.
After being amplified by the video amplification circuit 8, the signal is supplied to the light valve drive circuit 9, from which a drive signal for displaying an image is output to the liquid crystal panel 10. The liquid crystal panel 10 displays an image according to the above-mentioned drive signal, and transmits the light beam from the incident side (condenser lens 3) to the output side (projection lens 5) via this image. An enlarged image is projected onto a screen 7 via a projection lens 5 and an aperture 6.

Now, in order to display an enlarged image in color on the screen 7 using the projection type display device described above, which is equipped with the light control unit 4 that controls the liquid crystal panel 10, the liquid crystal panel 10
A color filter colored according to the pixels of the image displayed on the panel may be inserted inside the panel, a colored layer may be installed on the outside of the panel, or a polarizing plate placed on the outside of the panel (Fig. (not shown).
It was 1.

(Problems to be Solved by the Invention) The liquid crystal panels used in the above-mentioned projection type display devices employing a simple multiplex method do not require matrix drive because crosstalk occurs between the signal electrodes and the scan electrodes. The number of scanning electrodes is limited, and the structure of the J8 thin film transistor element forming the switching array is complicated in the case of using the aquive matrix method, so there is a problem that the yield in the manufacturing process is poor. As a result, it has been difficult to improve the image quality of a projected enlarged image by increasing the number of pixels in a projection display device using any of the above liquid crystal panels.

For example, the number of pixels has been increased by superimposing red (R), green (G), and blue (B) that correspond to people's colors on the projection screen, but it is difficult to adjust the registration. A problem arises.

Furthermore, in the case of a panel with a color filter, the mosaic or striped red, green, and blue pixel distribution of the color filter becomes noticeable and causes pixel loss, which reduces the image quality and makes it difficult to obtain a good color enlarged image. There was a very difficult problem.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a light valve that modulates a displayed image using projection light whose color changes sequentially at predetermined time intervals. A projection type display device is used, which is characterized in that the image displayed on the light valve is optically modulated by the projection light to cover a color display.

(Example) Hereinafter, a projection type display device according to the present invention will be described in detail with reference to the drawings. The same components as those described above are denoted by the same reference numerals, and their explanations will be omitted.

FIG. 1 is a specific configuration diagram of a first embodiment of a projection type display device according to the present invention.

The light control section 11 includes a video amplification circuit 8, a light valve drive circuit 9, a liquid crystal panel (light valve) 10A1, a circular filter 12. Synchronous separation circuit 13゜motor drive circuit 14.
It consists of an electric motor 15. The liquid crystal panel 108 is a third panel to be described later.
It has the configuration shown in the figure. The circular filter 12 has R, G
,B corresponds to J, the filter part 12 is divided into three parts.
A.

12B and 12C, which are rotatably arranged on the incident side of the liquid crystal panel IOA with a predetermined distance between them. The configuration for rotating this circular filter 12 is the synchronous separation circuit 13.
．． They are a motor drive circuit (MDA) 14 and an electric motor 15.

The video signal supplied to the video amplification circuit 8 is a video signal corresponding to one of R, G, and B for each field, and for example, the first field is an R image, and the second field is an R image. , . . . are sequentially supplied to the video amplification circuit 8. Furthermore, in order to reduce flicker, the number of fields is increased, and the chromaticity coordinates of the three primary colors are set such that the difference in brightness between the primary colors is reduced, thereby making it possible to obtain a clear image.

The relationship between the image update period displayed on the liquid crystal panel 10Δ and the rotation of the circular filter 12 is such that while an image for one field is displayed on the liquid crystal panel 10A, the circular filter 1
The R, G, and B filter portions 12A to 12C of No. 2 are in a forward-rotating relationship, and by synchronizing the operations of these two, a clear colored image can be obtained on the output side of the liquid crystal panel 10A. Ta.

Now, 120 rotations of the circular filter are performed as follows. A composite video signal output from the video amplification circuit 8 in accordance with one field of images displayed on the liquid crystal panel 10A is supplied to the synchronization separation circuit 13, from which a vertical synchronization signal obtained by separating the same 1g1 is obtained. is supplied to the motor drive circuit 14, from which a rotational drive pulse λ1 for rotating the motor 5 by -N rotations per field is output to the electric motor 5. A central shaft 12D of the circular filter 12 is supported on the rotating shaft 15A of the electric motor 150.

As a result, while an image for one field is being displayed on the liquid crystal panel 10A, the circular filter 12 will operate as shown in FIG.

Now, the operation of the projection type display device according to the present invention will be explained.

The projection light (white light) supplied from the lamp 1 that enters through the condenser lens 3 is R, G, and B.

The light enters the liquid crystal panel 1°A through filter portions 12A to 12C of the circular filter 12 that rotate as R5, . . . . The images displayed on the liquid crystal panel 10A are the first rotation (R, G, B) and the second rotation of the circular filter 12, which are sequentially switched.
Since the rotating eyes (R, G, B), etc. are switched in synchronization with each other, the enlarged projection image projected onto the screen γ via the projection lens 5 and diaphragm 6 is affected by the afterimage effect of the viewer's eyes. , perceived as a color image.

Filter portions 12A to 12 of the circular filter 12 described above
C can be created by printing dyed pigments on general thin films (organic or inorganic), color films, etc.

Note that the circular filter 12 is rotatably disposed on the incident side of the liquid crystal panel 10A with a predetermined spacing between them, but the circular filter 12 is rotatably disposed on the output side of the liquid crystal panel 10A with a predetermined spacing between the circular filters 12 and 10A. Of course, it is good to do so.

FIG. 2 is a detailed diagram of a second embodiment of the projection type display device according to the present invention.

Components that are the same as those described above are designated by the same reference numerals, and their explanations will be omitted. Hereinafter, the differences from the first embodiment described above will be explained.
We will only explain the configuration.

This embodiment differs from the first embodiment described above in that the light control unit 16 is supplied with light having wavelength regions of three primary colors, and the video signals of these lights are R and G.

In synchronization so that the color matches the reproduced image that switches to B, . After the light is modulated by the light bulb, a color image is formed which is projected onto the screen 70.

A circular control plate 1 is used as a means for blocking and transmitting light of each color.
7 to 1 were used, but it goes without saying that the invention is not limited to this.

In addition, light having wavelength ranges of three primary colors can be obtained by separating the white light emitted from a single lamp 1 using, for example, a dichroic mirror, or by combining lamps corresponding to each wavelength or lamps and color filters. may be provided respectively.

The light control unit 16 includes a video amplification circuit 8, a light valve drive circuit 9, a liquid crystal panel IOA, a synchronous separation circuit 13, an electric opening drive circuit 14, circular control plates 17 to 19, dichroic mirrors 20 to 22, and electric motors 23 to 25. be done. Circular control plates 17 to 1 are transparent parts 17A to 19A1 and light shielding parts 17
It is composed of B to 19B and central axes 17C to 19C, with 1/3 of the whole being transparent parts 17A to 19A and 2/3 of them.
are the light shielding parts 17B to 19B. Center axis 17C~19G
are pivotally supported by rotating shafts 23A to 25A of electric motors 23 to 25.

Dichroic mirrors 20-22 are circular control plates 17-1
Red light incident through the transmission parts 17A to 19A of 9,
It is used to combine green light and blue light and supply these lights to the liquid crystal panel IOA in a time-sharing manner.

FIG. 3 is an enlarged sectional view of a liquid crystal panel 10A constituting a light valve used in a projection display device according to the present invention.

That is, a pair of four-transparent substrates 26A made of glass plates, plastic plates, etc., and facing each other at a predetermined distance;
One surface 26AI of 26B.

Transparent electrodes 27A1 to 27A6°27B made of indium oxide film or tin oxide film are formed on 26B1, and these transparent electrodes 27A1 to 27Ae, 27B
On the surface of is an alignment film 2 for aligning the liquid crystal molecules.
8A and 28B are formed.

The alignment films 28A and 28B are made of an alignment agent such as polyimide or polyvinyl alcohol, and have a thickness of 10 μm.
They are formed so as to face each other in a plane 1j with a gap of mPiIm. And C1, as shown in the same figure, a transparent electrode 27B and an alignment film 28A.

Each periphery of the 28B1 transparent substrate 26A is covered with a sealing material 29A, 2
When sealed with 9B, the above-mentioned gap becomes a closed space. A liquid crystal layer 30 is formed by injecting liquid crystal into this closed space and sealing it again.

The alignment treatment of the liquid crystal molecules filled in this liquid crystal layer 30 is performed so that the long sleeves of the liquid crystal molecules are approximately 9
This is done in such a way that a twisted arrangement with a 0° twist is obtained. In the 11 liquid crystal filled in the liquid crystal layer 30, an appropriate chiral substance is appropriately added to the various liquid crystal substances used, such as the nemadic phase and the smectic phase.

Since the twist pitch of this liquid crystal molecule is sufficiently large compared to the wavelength of visible light, the polarization direction of linearly polarized light incident on the liquid crystal panel 10Δ via a polarizer 31A, which will be described later, is arranged on the incident side of the liquid crystal panel IOA. The light rotates and changes along the twist of the liquid crystal molecules, which changes depending on the increase/decrease in the applied voltage value applied between the transparent electrodes 27A to 27A6 and 27B while passing through the liquid crystal layer 30.

That is, the liquid crystal panel 10A has electrodes 27Δ1 to 27A6.
If no voltage is applied between the electrodes 27B, the linearly polarized light will be rotated approximately 90' and will be transmitted when the polarizer 31A is crossed Nicols. However, by applying a voltage between the electrodes and increasing the applied voltage value, this can be Accordingly, the polarization direction of the incident linearly polarized light changes, making it possible to transmit or block the light.

Now, the transparent substrate 26 of the liquid crystal panel 10A having the above configuration.
On the surfaces 26A2 and 26B2 of A and 26B, there are polarizers 31A and 3 whose change direction coincides with the long sleeve of the liquid crystal molecules.
1B was installed.

As described above, the projection type display device according to the present invention uses the liquid crystal panel 10A as a light valve, but it goes without saying that a panel capable of light modulation other than liquid crystal may be used.

(Effects of the Invention) As described above, the projection display device according to the present invention can increase the number of pixels of an enlarged image to be projected, and can be used to create a mosaic of color fill, stripes of red, green, etc. The effect is that it is possible to obtain good image quality in which the blue pixel distribution is not noticeable and pixel defects do not occur.

[Brief explanation of the drawing]

1 and 2 show the first part of the projection type display device according to the present invention.
A specific configuration diagram of the second embodiment, FIG. 3 is an enlarged cross-sectional view of a liquid crystal panel IOA constituting a light valve used in a projection display device according to the present invention, and FIG. 4 is a block diagram of a general projection display device. FIG. 5 is a diagram showing the configuration of a light control section 4 used in a conventional projection type display device. 1... Lamp, 2... Concave mirror, 3... Condenser lens, 4.11.16... Light control section, 5... Projection lens,
6...Aperture, 7...Screen, 8...Video amplification circuit 8.9...Light valve drive circuit, 10.10A...Liquid crystal panel (light valve), 12
...Circular filter, 13...Synchronization separation circuit, 14.
...Electric motor drive circuit, 15.23-25...Electric motor, 17-19...Circular control board, 20-22...Dichroic mirror.

Claims (1)

[Claims] It has a light valve that modulates the displayed image using projection light whose color changes sequentially at predetermined time intervals, and color display is performed by modulating the image displayed on the light valve with the projection light. A projection display device characterized by: