JP3044875B2 - Display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device such as a projection display device, a rear projector, and an overhead projector.

[0002]

2. Description of the Related Art A luminous flux whose intensity is modulated by each pixel signal in an image signal is scanned in a horizontal direction and a vertical direction, and the luminous flux is projected on a screen by a projection optical system to display a two-dimensional image. Although a display device that performs the operation is conventionally known, in the conventional technology, a high-brightness, high-resolution optical two-dimensional image using a time-series signal,
For example, even if it is required to form a high-definition two-dimensional image in which 4000 pixels are arranged vertically and horizontally in a state close to real time, there is no signal conversion element capable of realizing it. Therefore, such a request could not be satisfied.

The present applicant has proposed a display device which can solve the above-mentioned problems well, and can display a high-brightness and high-definition image very easily.
For example, a display device as disclosed in Japanese Patent Application Laid-Open No. 3-196121, that is, a light beam having a linear cross section emitted from a light source is displaced by a large number of reflecting members provided for each pixel in accordance with pixel information. The cross-sectional shape that is intensity-modulated for each pixel in the linear direction of the light beam with a linear cross section incident on the light modulating unit having a configuration that allows the light modulation unit to have a cross-sectional shape as a linear light beam The light beam emitted from the light modulation unit is emitted by the light deflecting device to deflect the light beam in a horizontal direction at a predetermined cycle and is incident on a projection lens. The light beam is projected onto a screen by the projection lens and is two-dimensionally projected on the screen. Although an apparatus for projecting an image has been proposed, in the above-described proposed apparatus, the light intensity modulation operation based on pixel information performed by the light modulation unit is delayed. It has become a problem.

[0004] Therefore, in the present applicant company, first, N light emitting elements (for example, light emitting diodes) corresponding to N pixels.
Are supplied to the N light emitting elements in the light emitting element array in which the light emitting elements are linearly arranged, for a predetermined period of time, information on the pixels corresponding to the respective light emitting elements is supplied to the N light emitting elements in the light emitting element array Causing the elements to emit light simultaneously over the period, to simultaneously deflect the light emitted from each of the light-emitting elements in a direction orthogonal to the alignment direction of the light emitted from each light-emitting element of the light-emitting element array, Deflected light forms an image on the photoconductive layer of the spatial light modulator, which includes at least the photoconductive layer member and the light modulating material layer member between the two electrodes, and reads the light to the spatial light modulator. And a display device in which image information read from the spatial light modulator is projected on a screen.

[0005]

By the way, as a display device constituted by using a spatial light modulator as described above, a display device capable of displaying a high-resolution and high-brightness image with a low afterimage is obtained. In such a case, a large amount of writing light is required. Therefore, in order to use the light emitted from the light source efficiently, the light emitted from the light source is condensed by a reflecting mirror and then converted into parallel light by a lens, so that the light use efficiency is increased and the large writing light is increased. Is getting done. However, since the light source that emits writing light intensity-modulated by pixel information has a finite size and is not a point light source, let the diffused light emitted from the light source be converted into a parallel light state by a lens and use it efficiently. However, light emitted from a light source that is not a point light source does not become a perfect parallel light beam, and the light utilization rate is reduced. If the light source that emits the writing light intensity-modulated by the pixel information is, for example, a long linear light source in which light-emitting diodes are linearly arranged to generate linear writing light, a linear light source is used. In order to condense the linear light emitted from the light source into parallel light,
Since a positive lens (convex lens) having a large aperture is required, configuring such an optical system increases costs.

[0006]

According to the present invention, a spatial light modulator having at least a photoconductive layer member and a light modulating material layer member between two electrodes has a light emission amount in accordance with write information. In a display device in which a writing operation is performed by forming writing light emitted from a light emitting element array in a state where light emitting elements to be modulated are linearly arranged on a photoconductive layer member by an imaging lens. Provided is a display device in which a cylindrical positive lens and a cylindrical negative lens having a cylindrical lens axis parallel to an extending direction of a linear writing light are disposed between the light source of the writing light and the imaging lens. I do.

[0007]

The linear writing light emitted from the linear light source is
After being converged by the cylindrical positive lens provided so that the direction in which the linear writing light extends and the cylindrical axis are parallel to each other, the linear writing light extends. The light is incident on the imaging lens in a state where it is diverged by the cylindrical negative lens that is installed so that the direction and the cylindrical axis are parallel, and the light emitted from the imaging lens is applied to the photoconductive layer member of the spatial light modulator. It is imaged. As a result, the writing light emitted from the linear light source is effectively used for writing information to the spatial light modulation element without receiving a large loss.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific contents of a display device of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a schematic configuration of a display device of the present invention, and FIG. 2 is a plan view and a view of a part of an optical system for explaining a configuration principle and an operation principle of the display device of the present invention. FIG. 3 is a diagram showing resolution characteristics of the display device of the present invention. 1 and 2, LLS is a linear light source, CLp is a cylindrical positive lens (cylindrical convex lens) having a cylindrical axis parallel to the direction in which the linear writing light extends, and CLm is the linear writing described above. A cylindrical negative lens (cylindrical concave lens) having a cylindrical axis parallel to the direction in which light extends, Mg is an oscillating mirror (galvano mirror), Lo is an imaging lens, and SLM is at least a photoconductive layer member between two electrodes. This is a spatial light modulator including a light modulating material layer member. PBS is a polarizing beam splitter, LS is a light source of readout light, Lp is a projection lens, and S is a screen. As the above-mentioned linear light source LLS, for example, each of them emits light whose intensity is modulated by pixel information.
The linear light source LLS may be configured to linearly arrange the light emitting diodes to generate linear writing light. The linear writing light emitted from the linear light source LLS is a cylindrical positive lens CL having a cylindrical axis parallel to the direction in which the linear writing light extends.
p, which is condensed by p and has a cylindrical axis parallel to the direction in which the linear writing light extends,
The beam is diverged by Lm and enters the oscillating mirror Mg. The linear writing light incident on the oscillating mirror Mg while extending in the oscillating axis direction of the oscillating mirror Mg is caused by the oscillating operation of the oscillating mirror Mg in the direction of the arrow Y in FIG. In the state where the light is deflected, the light is focused by the imaging lens Lo and is imaged on the photoconductive layer member PCL of the spatial light modulator SLM.

FIG. 2 shows components of the display device shown in FIG. 1 in order to simplify the explanation of the configuration principle and operation principle of the optical system from the linear light source LLS to the spatial light modulator SLM. FIG. 3 is a plan view of the optical system in a state where the oscillating mirror Mg has been removed from FIG.
The distance from S to the main plane of the cylindrical positive lens CLp,
L2 indicates the distance from the main plane of the cylindrical positive lens CLp to the cylindrical negative lens CLm. Now, since the writing light emitted from the linear light source LLS is non-parallel light,
As illustrated in FIG. 2, the light enters the cylindrical positive lens CLp while being diffused from the linear light source LLS. The above-described cylindrical positive lens CLp emits light incident thereon as light in a state of being condensed only in a direction orthogonal to the cylindrical axis on the main plane of the cylindrical positive lens CLp.

The non-parallel state radiated from the linear light source LLS by the cylindrical positive lens CLp arranged so that the direction of the cylindrical axis is parallel to the extending direction of the linear writing light as described above. If the writing light is made to enter the imaging lens Lo in a condensed state, the cylindrical positive lens CLp
Although the use efficiency of the non-parallel writing light emitted from the linear light source LLS is improved as compared with the case where
Since the light condensing action by the cylindrical positive lens CLp is performed only in the direction orthogonal to the cylindrical axis on the main plane of the cylindrical positive lens CLp, this light is converted into spatial light by the imaging lens Lp. Modulation element S
Even if an image is formed on the photoconductive layer member PCL of the LM, the resolution in the horizontal direction and the vertical direction of the image is greatly different, and recording and reproduction of a high-resolution image cannot be performed.

In the display device of the present invention, the light emitted from the positive cylindrical lens CLp is passed through the negative cylindrical lens CLm arranged such that the direction of the cylindrical axis is parallel to the extending direction of the linear writing light. By causing the light to enter the imaging lens Lo, the cylindrical negative lens CLm
The incident light from the positive cylindrical lens CLp is diffused only in the direction orthogonal to the cylindrical axis on the main plane of the negative cylindrical lens CLm, and the light is diffused by the imaging lens Lo into the photoconductive layer of the spatial light modulator SLM. When an image is formed on the member PCL, the difference in resolution between the horizontal direction and the vertical direction of the image is eliminated, and recording and reproduction of a high-resolution image are performed using light emitted from the light source efficiently. We are trying to get it.

In the display device of the present invention, the linear light source L
A cylindrical positive lens CLp having a focal length of 40 mm is installed at a distance L1 (= 38.2 mm) from LS, and a distance L2 (= 2) from the position of the main plane of the cylindrical positive lens CLp.
(39 mm), a cylindrical negative lens CLm having a focal length of 300 mm is installed, and a linear writing light whose intensity is modulated by image information emitted from a linear light source LLS is a cylindrical positive lens described above. CLp and cylindrical negative lens C
Lm, the light enters the oscillating mirror Mg, and is deflected by the oscillating mirror Mg.
The horizontal resolution and the vertical resolution of the image formed on the M photoconductive layer member PCL are as shown by the curves 1S and 1T in FIG. 3, respectively. When the cylindrical positive lens CLp and the cylindrical negative lens CLm are interposed between the light source LLS and the imaging lens Lo, the light quantity of the image is determined by the cylindrical positive lens CLp between the linear light source LLS and the imaging lens Lo. And 10 times the case where the cylindrical negative lens CLm was not interposed.

In FIGS. 1 and 2, SLM is a spatial light modulator, PBS is a polarization beam splitter, LS is a light source for readout light, Lp is a projection lens, and S is a screen. The writing light imaged by the imaging lens Lo on the photoconductive layer member PCL of the spatial light modulator SLM is transmitted by the spatial light modulator S
The image information which is projected on the LM and is to be displayed is written in the spatial light modulator SLM. The spatial light modulator SLM described above includes, for example, a transparent substrate BP1 and a transparent electrode Et.
A structure formed by laminating 1, a photoconductive layer member PCL, a dielectric mirror DML, a light modulating material layer member PML, a transparent electrode Et2, and a transparent substrate BP2 may be used.

In the spatial light modulator SLM, the transparent electrodes Et1 and Et2 are formed of a thin film of a transparent conductive material, and the photoconductive layer member PCL is made of a material which exhibits photoconductivity in the wavelength region of light used. For example, hydrogenated amorphous silicon (a-Si-H) may be used. Further, as the dielectric mirror DML, a well-known type formed as a multilayer film so as to reflect light in a predetermined wavelength band can be used. Further, as the light modulation material layer member PML, for example, an electric field control type A light modulating material layer member composed of a nematic liquid crystal having a refractive effect and having a negative dielectric anisotropy as a vertical alignment is used. E is a power supply for applying a predetermined voltage between the transparent electrodes Et1 and Et2.

N writing light fluxes, the intensity of which is modulated by image information, enter from the transparent substrate BP1 side of the spatial light modulator SLM to which a predetermined voltage is supplied from the power supply E between the transparent electrodes Et1 and Et2. When it is focused on the photoconductive layer member PCL in the spatial light modulator SLM,
The electrical resistance value of the photoconductive layer member PCL at the portion where the above-mentioned N writing light beams are condensed changes with high sensitivity in accordance with the irradiated light amount, and the photoconductive layer member PCL and the dielectric mirror DML are changed. A charge image corresponding to the irradiation light amount by the N writing lights whose intensity is modulated by the image information to be displayed is favorably formed at the boundary between
Thereby, the light modulating material layer member PM of the spatial light modulating element SLM
An electric field due to N charge images formed at the boundary between the photoconductive layer member PCL and the dielectric mirror DML is applied to L.

When the readout light in the visible region emitted from the readout light source LS is incident on the polarization beam splitter PBS, the S-polarized light component of the readout light RL is converted by the polarization beam splitter PBS into the readout side of the spatial light modulator SLM. And enters from the transparent substrate BP2 on the reading side of the spatial light modulator SLM. As described above, the read light RL incident from the transparent substrate BP2 side of the spatial light modulator SLM reaches the dielectric mirror DML through the route of the transparent substrate BP2 → the transparent electrode Et2 → the light modulation material layer member PML → the dielectric mirror DML. The reflected light of the read light reflected there is transmitted to the spatial light modulator S through the path of the dielectric mirror DML → the light modulating material layer member PML → the transparent electrode Et2 → the transparent substrate BP2 →.
Emitted from the LM.

The luminous flux of the N readout lights simultaneously emitted from the spatial light modulator SLM as described above is a charge in a state in which charges of a charge amount corresponding to N pieces of sequential pixel information are arranged. Since the light beam is a light beam that has reciprocated through the light modulating material layer member PML to which an electric field due to an image is applied, the light beam changes the state of the polarization plane corresponding to the N pieces of sequential pixel information linearly arranged. Is what it is. And
The N readout lights simultaneously emitted from the spatial light modulator SLM are incident on the polarization beam splitter PBS, and the P-polarized light component of the incident light is simultaneously supplied from the polarization beam splitter PBS to the projection lens Lp, and projected. The lens Lp simultaneously projects it as N light spots linearly arranged on the screen S. The display device may be configured using a transmission type spatial light modulation element as the spatial light modulation element SLM.

[0018]

As apparent from the above description, the display device of the present invention has a spatial light comprising at least a photoconductive layer member and a light modulating material layer member between two electrodes. A writing operation is performed in which a writing light emitted from a light emitting element array in which light emitting elements whose light emission amount is modulated in accordance with write information is linearly arranged on a modulation element is formed on a photoconductive layer member by an imaging lens. Is performed, the cylindrical positive lens and the cylindrical negative lens having a cylindrical lens axis parallel to the direction in which the linear writing light extends, the light source of the writing light and the imaging lens, Since the display device is disposed between the linear writing light emitted from the linear light source, the direction in which the linear writing light extends and the cylindrical axis are parallel. A circle that is set to become After being focused by a positive lens,
The direction in which the linear writing light extends and the cylindrical axis are parallel to each other, and are diverged by a cylindrical negative lens provided so as to be incident on an imaging lens, and the light is imaged. When an image is formed on the photoconductive layer member PCL of the spatial light modulator SLM by the lens Lo, the difference in resolution between the horizontal direction and the vertical direction of the image is eliminated, and recording and reproduction of a high-resolution image is performed from the light source. Since the irradiation is performed in a state where the emitted light is used efficiently, the conventional problems described above can be solved well in the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a part of a display device of the present invention.

FIG. 2 is a plan view of a part of an optical system for explaining a configuration principle and an operation principle of the display device of the present invention.

FIG. 3 is a diagram illustrating resolution characteristics of the display device of the present invention.

[Explanation of symbols]

LLS: linear light source, CLp: cylindrical positive lens (cylindrical convex lens) having a cylindrical axis parallel to the direction in which the linear writing light extends, CLm: direction in which the linear writing light extends , A cylindrical negative lens (cylindrical concave lens) having a cylindrical axis parallel to, Mg ... an oscillating mirror (galvano mirror), Lo ... an imaging lens, SLM ... a spatial light modulator, PBS ... a polarizing beam splitter, LS ... a light source for readout light , Lp: projection lens, S: screen,

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fushiko Tatsumi 3-12-12 Moriyacho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Within (72) Inventor Ryusaku Takahashi 3-12 Moriyacho, Kanagawa-ku, Yokohama, Kanagawa (72) Inventor Tsutomu Matsumura 3-12, Moriyacho, Kanagawa-ku, Yokohama, Kanagawa, Japan (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/135

Claims (1)

(57) [Claims] 1. A light emitting element whose light emission amount is modulated in accordance with write information is linearly arranged on a spatial light modulating element including at least a photoconductive layer member and a light modulating material layer member between two electrodes. In a display device in which a writing operation is performed by forming writing light emitted from a light-emitting element array in a spatially arranged state on a photoconductive layer member by an imaging lens, the linear writing light A display device comprising: a cylindrical positive lens and a cylindrical negative lens having a cylindrical lens axis parallel to the direction in which the lens is located; and a light source for writing light and an imaging lens.