JP4152811B2 - Image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display device that displays an image by modulating a light beam from a light source according to an image signal using a non-light emitting display element.
[0002]
[Prior art]
In general, a non-light-emitting image display device changes the light transmittance (or reflectance) of a plurality of pixels according to a drive signal and modulates the intensity of light applied to an image display element (display panel) to thereby generate an image. And a character display structure. Such an image display device includes a direct viewing mode (direct viewing type image display device) and a projection mode in which an image and characters are enlarged and projected on a screen by a projection optical system (projection type image display device).
[0003]
A projector (including a front type and a back type) uses a color display panel in which color filters of red, green, and blue (hereinafter referred to as R, G, and B) are arranged as image display elements to be used. And a three-plate type using three display panels for monochrome display.
[0004]
Non-light emitting image display elements include liquid crystal display elements, electrochromic display elements, and electrophoretic display elements. Among them, liquid crystal display elements are widely used in, for example, monitors, personal digital assistants, mobile phones and projectors. ing.
[0005]
The liquid crystal display element displays images, characters, etc. by changing the optical characteristics of the liquid crystal layer in the pixel opening by applying drive voltages corresponding to image signals to the pixel electrodes regularly arranged in a matrix. Is configured to do. As a method of applying an independent driving voltage to the pixel electrode described above, there are a simple matrix method and an active matrix method in which a nonlinear two-terminal element or a three-terminal element is provided in a liquid crystal display element.
[0006]
In the case of the latter active matrix system, a switching element such as an MIM (metal-insulator-metal) element or a TFT (thin film transistor) element and a wiring for supplying a driving voltage to the pixel electrode are provided. When strong light is incident on this switching element, the element resistance in the OFF state decreases, and not only the charged charge is discharged when a voltage is applied, but also the normal driving of the liquid crystal layer in the area where the switching element and wiring are formed Since no voltage is applied and the original display operation is not performed, for example, there is a problem that light leakage occurs in a black display state and the contrast ratio of the display is lowered.
[0007]
Therefore, for example, a transmissive liquid crystal display element is disposed so as to face a TFT substrate through a TFT substrate provided with a switching element and a pixel electrode and a liquid crystal layer in order to block light incident on the above-described region. A light shielding layer called a black matrix is provided on the counter substrate. For this reason, in the case of a transmissive liquid crystal display element, in addition to a light-shielding TFT, a gate bus line, and a source bus line, light is shielded by a black matrix. The area of the part, that is, the aperture ratio decreases.
[0008]
Furthermore, it is difficult to form these switching elements and wiring electrodes to a certain size due to restrictions on their electrical performance and manufacturing technology. Therefore, as the pitch of the pixel electrodes is decreased, the aperture ratio is further decreased as the liquid crystal display element is increased in definition and size.
[0009]
As the aperture ratio decreases, the light transmitted through the liquid crystal display element decreases, so that the liquid crystal projector that projects a small panel on a large screen has insufficient brightness. In particular, in a single-plate projector, the brightness is greatly reduced due to light absorption by the color filter.
[0010]
As one method for solving this problem, a method of providing a microlens for condensing light at individual pixel openings of the liquid crystal display element and improving the effective aperture ratio of the liquid crystal display element has been put into practical use.
[0011]
In Patent Document 1, white light is incident on a dichroic mirror arranged in a fan shape, divided into R, G, and B color light beams, and each color light beam is applied to a microlens disposed on the light source side of the liquid crystal display element. A system is disclosed in which light beams are incident at different angles and a predetermined color beam is condensed on pixels corresponding to each color. By adopting this method, in addition to the effect of improving the effective aperture ratio by the microlens, light absorption by the color filter can be eliminated.
[0012]
With this method, it is possible to eliminate the loss caused by the color filter that has occurred in conventional single-plate projectors, while taking advantage of the single-plate projectors that can reduce the number of parts and reduce costs, thereby realizing a bright image. Can do. Further, this method eliminates the problem of display failure and fading due to deterioration of the color filter itself.
[0013]
With reference to FIGS. 7A and 7B, two typical methods of manufacturing a counter substrate having a conventional microlens will be described.
[0014]
In the first manufacturing method, a counter substrate including a microlens array is manufactured by a process schematically shown in FIG.
[0015]
(1) The photoresist layer on the glass substrate is patterned. {Circle around (2)} The patterned resist layer is heated to cause dripping and form a resist layer having a microlens shape. (3) The glass substrate is dry-etched together with the microlens-shaped resist layer to form (etch back) the shape of the resist layer on the glass substrate to obtain a microlens array substrate. (4) A cover glass is bonded to the obtained microlens array substrate through an adhesive layer, and the surface of the cover glass is polished to obtain a counter substrate. In addition, an electrode, an alignment film, etc. are formed as needed.
[0016]
In the second manufacturing method, a counter substrate including a microlens array is manufactured by a process schematically shown in FIG.
[0017]
(1) The photoresist layer on the glass substrate is patterned by, for example, electron beam exposure to form a resist layer having a microlens shape. This is the master (original version). {Circle around (2)} A metal stamper is produced using a master, for example, by plating. (3) Using a metal stamper, the shape of the microlens is transferred to a glass substrate to obtain a microlens array substrate. (4) A cover glass is bonded to the obtained microlens array substrate through an adhesive layer, and the surface of the cover glass is polished to obtain a counter substrate.
[0018]
[Patent Document 1]
Japanese Patent Laid-Open No. 4-60538
[0019]
[Problems to be solved by the invention]
However, the single-plate projector disclosed in Patent Document 1 has a problem that color mixing occurs as described below.
[0020]
As schematically shown in FIG. 8, this type of image display apparatus includes a microlens array 7 disposed on the light incident side of the liquid crystal display element 8. The microlens array 7 has a plurality of microlenses 7a and a base substrate 7b, and one microlens 7a is arranged so as to correspond to three pixel openings 8a of R, G, and B. The pixel openings 8a of the liquid crystal display element 8 are separated from each other by a light-shielding portion 8b, and the R, G, and B color light fluxes are condensed on the corresponding pixel openings 8a by the microlens 7a (solid line in FIG. 8). Color display is realized by referring to the luminous flux shown in FIG. When the R, G, and B color light fluxes enter the pixel aperture 8a adjacent to the corresponding pixel aperture 8a (see the light flux indicated by the broken line in FIG. 8), color mixing occurs and the color reproduction range of the display deteriorates. . In FIG. 8, only one color (G light flux) is shown for simplicity of explanation, but color mixing also occurs in the other two color light fluxes.
[0021]
If the microlens is an ideal lens with no aberration, color mixing hardly occurs, but usually has aberrations such as spherical aberration, and even if perfect parallel light is incident, the condensed spot is 1 It does not gather at the point, but spreads to a certain size. Further, the lens shape is found near the boundary between the lenses of the microlens, and the light collecting effect is reduced. Furthermore, in order to improve the brightness, if a configuration is adopted in which light with a parallelism such that the light condensing spot of the microlens is approximately the same size as the pixel opening or one time larger is used, color mixing tends to occur. .
[0022]
In addition, the influence of the decrease in color purity becomes greater as the light having a weak spectral intensity (for example, light in the R wavelength region in a high-pressure mercury lamp often used in a liquid crystal projector). This is because the relative light quantity of other color light fluxes that are mixed with the color light flux that originally contributes to display increases.
[0023]
The present invention has been made in view of the above-described points, and a main object thereof is to provide a bright image display device having a wide color reproduction range.
[0024]
[Means for Solving the Problems]
An image display device according to the present invention includes a light source; a color separation element that separates a light beam emitted from the light source into first, second, and third color light beams in different wavelength ranges and emits the light beams at different angles. A light-shielding portion and first, second, and third pixel openings that are separated from each other by the light-shielding portion, and the second and third pixel openings are interposed between the first pixel openings. An image display element having a plurality of pixels composed of the first, second, and third pixel openings arranged in a predetermined pitch along a predetermined direction so as to sandwich; the color separation element and the image A plurality of light collecting elements provided one-on-one with respect to the plurality of pixels between the display elements and the first, second, and third color light fluxes that have passed through each of the light collecting elements. Of the surface defined by the plurality of pixels. Are the first, second, and third focused spots, respectively, the center of the first focused spot is formed in the first pixel opening, and the center of the second focused spot is the first focused spot. The center of the third focused spot is formed in the third pixel opening, and the center of the first focused spot and the center of the second focused spot in the predetermined direction are formed. The distance (D) between the center (Da) and the distance (Db) between the center of the first focused spot and the center of the third focused spot is larger than the predetermined pitch (P). It is characterized by being large, thereby achieving the above object.
[0025]
In one embodiment, the center of the first focused spot is formed at the center of the first pixel opening.
[0026]
In one embodiment, the spectral intensity of the first color light beam is weaker than the spectral intensity of the second and third color light beams.
[0027]
In one embodiment, the first color light beam is a red light beam.
[0028]
In one embodiment, each of the plurality of condensing elements is a microlens, and constitutes a two-dimensional microlens array. A microlens prism may be used instead of the microlens.
[0029]
In one embodiment, the width (Ws) of the first, second, and third focused spots in the predetermined direction is the width (Wp) of the first, second, and third pixel openings in the predetermined direction. ).
[0030]
In one embodiment, when the width of the light shielding portion in the predetermined direction is Wb, the at least one distance (D) satisfies the relationship of P <D <P + Wb.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image display device according to an embodiment of the present invention will be described with reference to the drawings. Although a projection type liquid crystal display device is exemplified, the present invention can be applied to an image display device using a non-light emitting display element other than the liquid crystal display element.
[0032]
FIG. 1 is a diagram schematically illustrating a configuration of a projection type liquid crystal display device 100 according to the embodiment. The liquid crystal display device 100 divides the light source 101 and the light beam 10 emitted from the light source 101 into first, second, and third color light beams (R, G, and B) in different wavelength ranges, and each of them has a different angle. , A liquid crystal display element 108 having a plurality of pixels, and a condensing element group 107 provided between the color separation element 106 and the liquid crystal display element 108. The luminous flux modulated and emitted by the liquid crystal display element 108 is projected onto the screen 110 via the projection lens 109.
[0033]
For example, after the light emitted from the light source 101 is converted into substantially parallel light by the parabolic mirror 102, the light passes through the fly-eye lens 103 including the pair of lens arrays 103 a and 103 b and the field lenses 104 and 105. , And enters the color separation element 106. The color separation element 106 includes, for example, three dichroic mirrors 106R, 106G, and 106B, and separates the color light flux into an R light beam 10R, a G light beam 10G, and a B light beam 10B. These color light beams 10R, 10G, and 10B are incident on the condensing element group 107 at different angles.
[0034]
With reference to FIG. 2, the configuration and function of the light collecting element group 107 will be described. As the condensing element group 107, for example, a microlens array 107 shown in FIG. 2 can be used. The microlens array 107 has a plurality of microlenses 107a as a condensing element.
[0035]
The liquid crystal display element 108 has a plurality of pixels, and each pixel has a plurality of pixel openings (for example, first pixel openings) corresponding to different color light beams (for example, the R light beam 10R, the G light beam 10G, and the B light beam 10B). Part 108R, second pixel opening 108G and third pixel opening 108B). Here, as shown in FIG. 2, the arrangement of the pixel openings in each pixel is such that the first pixel openings 108G and the third pixel openings 108B are in a predetermined direction (typical) so as to sandwich the first pixel openings 108R. Are arranged at a predetermined pitch P along the row direction. Note that the R light beam 10R, the G light beam 10G, and the B light beam 10B are incident on the microlens array 107 at different angles in a plane including the row direction.
[0036]
Each microlens 107a included in the microlens array 107 is provided on a one-to-one basis with respect to a plurality of pixels, and the color beams (R beam 10R, G beam 10G, and B beam 10B) that have passed through the microlens 107a are provided. The centers of the focused spots on a plane defined by a plurality of pixels (sometimes referred to as “pixel plane”) are the corresponding pixel openings (first, second and third pixel openings 108R, 108G and 108B). ).
[0037]
Here, an example is shown in which the color light fluxes are converged in the corresponding pixel openings, but as described later with reference to FIG. The passed color light beam may be converged to the microlens side from the pixel surface. On the contrary, it may be converged on the emission side. In this specification, unless otherwise specified, the “condensation spot” corresponds to the cross-sectional profile of the color light beam on the pixel surface and does not need to coincide with the convergence point (the point where the cross-sectional area of the color light beam becomes the smallest). In addition, the “center of the condensing spot” in this specification is a center in consideration of the light intensity distribution on the pixel surface, has an outer shape corresponding to the cross-sectional profile of the condensing spot, and has a light intensity distribution. Corresponds to the center of gravity of the paper with the corresponding density distribution. When the light intensity distribution is symmetric with respect to the geometric center of gravity of the cross-sectional profile of the focused spot, the “center of the focused spot” coincides with the geometric center of gravity. If it has an asymmetric intensity distribution due to the influence, it may deviate from the geometric center of gravity.
[0038]
The conventional image display device is designed so that the centers of these three focused spots are respectively formed at the centers of the corresponding pixel openings. Therefore, when color mixing occurs as described above with reference to FIG. 8, the color purity of colored light (for example, R) having a weak spectral intensity is most reduced.
[0039]
On the other hand, in the liquid crystal display device 100 according to the embodiment of the present invention, the three focused spots are formed at positions as shown in FIG.
[0040]
FIG. 3 is a plan view schematically showing the positional relationship between the focused spots 12R, 12G, and 12G and the corresponding pixel openings 108R, 108G, and 108G in the liquid crystal display device 100 according to the embodiment of the present invention.
[0041]
The pixel openings 108R, 108G, and 108G each have a width Wp in the row direction and are arranged in the row direction at a constant pitch P. A light shielding portion 108b having a width in the row direction Wb is disposed between adjacent pixel openings. Accordingly, in the row direction, the relationship of the pixel opening pitch P = the pixel opening width Wp + the light shielding portion width Wb is established. Further, each of the focused spots 12R, 12G, and 12B is approximately the same size as the pixel opening, and the width Ws in the row direction is substantially equal to the width Wb of the pixel opening.
[0042]
Out of the respective condensed spots 12R, 12G, and 12B of the three colored light beams 10R, 10G, and 10B, the center of the R condensed spot 12R formed in the central pixel opening 108R is the center of the pixel opening 108R. It is formed so as to substantially match. The G condensing spot 12G of the G light flux 10G is formed at a position where the distance Da between the center thereof and the center of the R light condensing spot 12R (that is, the center of the R pixel opening 108R) is larger than the pitch P. The center of the B condensing spot 12B of 10B is also formed at a position where the distance Db from the center of the R condensing spot 12R is larger than the pitch P. Here, the case where both the G condensing spot 12G and the B condensing spot 12B are formed so that the center is located at a position separated from the R condensing spot 12R by a pitch P or more is illustrated. Only one of the 12G and B condensing spots 12B may be configured such that the center Da is formed at a position where the distance Da (or Db) from the center of the R condensing spot 12R is larger than the pitch P. .
[0043]
In this way, the condensing spot (here, the R condensing spot 12R) corresponding to the color light beam having the weakest spectrum intensity among the R condensing spot 12R, the G condensing spot 12G, and the B condensing spot 12B is set at the center of the pixel. The G condensing spot 12G and the B condensing spot 12B are formed on both sides thereof, and the center of each of the G condensing spot 12G and the B condensing spot 12B and the R condensing spot 12R. By making the center and the interval (Da and Db) larger than the pitch P, it is possible to prevent the B light beam and the G light beam from being mixed with the R light beam and to suppress the decrease in the color purity of R. For the B and G beams, color mixing is likely to occur, but since the spectral intensity of these colored lights is higher than that of the R beam, the decrease in color purity is relatively small.
[0044]
As described above, a high-pressure mercury lamp (such as a UHP lamp manufactured by Philips) or a metal halide lamp that is usually used as a light source of a projection liquid crystal display device has a spectrum of R light as compared with G light or B light. Since the strength is weak and R is greatly affected by color mixing when color mixing occurs, it is preferable to employ the above-described configuration.
[0045]
The relationship between the degree of color mixing and the color reproduction range will be described with reference to FIGS. FIG. 9A is a CIE chromaticity diagram for the conventional liquid crystal display device, and FIG. 9B is a CIE chromaticity diagram for the liquid crystal display device of the present embodiment. A UHP lamp manufactured by Philips was used as the light source. In addition, the color mixture ratio in FIGS. 9A and 9B indicates the stray light amount incident on the adjacent pixel opening as a percentage, and the color mixture ratio 1% is incident on, for example, a liquid crystal display element. When the total light amount of the G light beam is 100%, the amount of stray light incident on the pixel opening corresponding to the adjacent R light beam is 1% of the total light amount of the G light beam (G light beam with respect to the R light beam). Color mixing). The stray light from the B light beam also enters the pixel opening corresponding to the R light beam (mixed color of the B light beam with respect to the R light beam). Similarly, stray light is incident on the pixel opening corresponding to the G light beam from the R light beam and B light beam, and stray light is incident on the pixel opening corresponding to the B light beam from the G light beam and R light beam.
[0046]
Therefore, as described above, when a light source having a weak spectral intensity of the R light beam is used as compared with the G light beam and the B light beam, the G light beam and the B light beam having a stronger spectral intensity in the R light beam even with the same color mixing ratio. Since stray light is incident, it is greatly affected by color mixing.
[0047]
First, as can be seen from FIG. 9 (a), in the conventional liquid crystal display device, the chromaticity of R (x = 0.6 to 0.7, y = 0) even with the same color mixture ratio (1% or 2%). .3) is greatly changed by B and G. On the other hand, in the liquid crystal display device according to the embodiment of the present invention, as shown in FIG. 9B, the amount of change in R chromaticity due to color mixture is reduced.
[0048]
Further, as can be seen from FIGS. 9A and 9B, by separating the G and B condensing spots from the center of the R pixel opening, the G and B condensing spots approach each other, and G and The amount of stray light with B slightly increases, but since these color lights originally have a strong spectral intensity, there is no large chromaticity shift that greatly affects the display quality.
[0049]
In the liquid crystal display device 100 according to the present embodiment, the interval Da or Db (represented by “D” as a representative thereof) includes the width Wb of the light shielding portion 108b in the row direction and the pitch P of the pixel openings, and P < It is preferable to satisfy the relationship of D <P + Wb. When the above relationship is satisfied, as shown in FIG. 3, it is suppressed that the G condensing spot 12G and the B condensing spot 12B overlap the adjacent pixel openings, and the color purity of these color lights is reduced. It can be suppressed / prevented.
[0050]
This will be described with reference to FIG. In FIG. 4, L indicates the distance between the G focused spot and the B focused spot, and M indicates the distance between the R focused spot and the G focused spot (or B focused spot).
[0051]
As described above, separating the G and B condensing spots with respect to the R condensing spot more than the pitch P of the pixel opening portion brings the G and B condensing spots closer to each other. As a result, for example, when the G light beam is directly incident on the pixel opening corresponding to the B light beam, the color purity of the B light beam is extremely deteriorated.
[0052]
Here, if the distances Da and Db are set so as to satisfy the above relationship, for example, as shown in FIG. 3, the pixel openings 108G and the pixels adjacent to the pixel openings 108R corresponding to R are arranged. The condensing spots 12G and 12B formed in the opening 108B approach the pixel opening corresponding to the adjacent B light beam and the pixel opening corresponding to the G light beam, but as described above, the G light beam (or It is possible to suppress or prevent the B light beam) from directly entering the pixel opening corresponding to the B light beam (or G light beam), and to suppress a decrease in color purity of these color light beams.
[0053]
In FIG. 3, for the sake of simplicity of explanation, the condensing spots formed at the pixel openings at the left and right ends are not shown, but in reality, the R, G, and B light fluxes correspond to the arrangement of the pixels. The condensing spots are periodically formed.
[0054]
Even if the distance D (Da or Db) is within the range of the relational expression, the color purity of the light beams of the G light beam and the B light beam decreases as the distance D increases due to the influence of the aberration of the microlens. However, since the G and B light fluxes originally have a strong spectral intensity, there is no significant change in chromaticity that greatly affects the display quality.
[0055]
In addition, when the width Wb of the light shielding portion 108b between the pixel openings is different in one pixel, it is preferable to design using the smallest value.
[0056]
In the embodiment described above, the width Ws in the row direction of the condensed spots 12R, 12G, and 12B of the light beams of the respective colors is made substantially the same as that of the pixel openings 108R, 108G, and 108B, Although the configuration substantially coincident with the center is illustrated, the present invention is not limited to this. For example, the size of the condensing spot of each color light beam may be set slightly larger than the pixel opening, or the center of the R condensing spot 12R may be set. You may shift from the center of pixel opening part 108R. Furthermore, although the example in which the color light beam having the weakest spectral intensity among the plurality of color light beams is associated with the central pixel opening is shown, the present invention is not limited to this, and the color light beam for which improvement in color purity is desired is displayed in the center. You may make it respond | correspond to a pixel opening part.
[0057]
In the above description, the example in which the color light flux that should suppress the occurrence of color mixing is associated with the central pixel opening in one pixel is described, but the present invention is not limited to this.
[0058]
For example, in the pixel array shown in FIG. 3, in order to prevent stray light of the R light beam 10R and the B light beam 10B from entering the pixel opening 108G, the center of the G light collecting spot 12G is set as the center of the pixel opening 108G. The center of the R condensing spot 12R may be shifted to the right in the drawing from the center of the pixel opening 108R, and the center of the B condensing spot 12B may be shifted to the left in the drawing from the center of the pixel opening 108B. At this time, the distance (Da) between the center of the G condensing spot 12G and the center of the R condensing spot 12R is larger than the pitch P of the pixel openings, and the center of the R condensing spot 12R and the center of the B condensing spot 12B. (Db) is smaller than the pitch P of the pixel openings, but when viewed from the center of the G focused spot 12G, the distance from the right R focused spot and the left B focused spot ( Since the interval between each pixel and the pixel belonging to the adjacent pixel is larger than the pitch P of the pixel openings, stray light is prevented from entering.
[0059]
A more specific configuration of the liquid crystal display device 100 of the present embodiment shown in FIGS. 1 to 3 will be described. As the light source 101, a UHP lamp manufactured by Philips with 120 W and an arc length of 1.4 mm was used.
[0060]
The microlens array 107 shown in FIG. 2 is manufactured by, for example, a known method described with reference to FIG. At this time, prior to manufacturing the liquid crystal display element 108, it may be formed on the counter substrate.
[0061]
The pitch P of the pixel openings 108R, 108G, and 108B of the liquid crystal display element 108 is, for example, 21 μm, and the width of each pixel opening in the color separation direction (for example, the row direction) is 18 μm. The distance between the microlens 107a and the pixel opening (the thickness of the cover glass substrate) is 150 μm (the optical distance corresponds to about 100 μm obtained by dividing the thickness of the cover glass by the refractive index of the cover glass).
[0062]
The parallelism of the illumination light emitted from the light source 101 was adjusted so that the condensing spots 12R, 12G, and 12B by the microlens 107a had the same size as the pixel openings 108R, 108G, and 108B.
[0063]
Here, in order to arrange the condensing spots 12R, 12G, and 12B corresponding to the pixel openings 108R, 108G, and 108B at a pixel pitch P of 21 μm as in the conventional case, the R light beam 10R and the G light beam are arranged. The color separation angle with respect to 10B and the color separation angle θ1 between the R light beam 10R and the B light beam 10B are adjusted to the following angles.
[0064]
θ1 = tan ^-1 (21/100) = 11.9 °
[0065]
On the other hand, in the liquid crystal display device 100 of the present embodiment, the center of the G condensing spot 12G and the B condensing spot 12B is the pixel pitch P with respect to the center of the R condensing spot 12R (= center of the pixel opening 108R). The color separation angle θ2 between the R light beam 10R and the G light beam 10G, and the R light beam 10R and the B light beam 10B is adjusted to the following angle so that the distance Da = Db = 23 μm is formed. did.
[0066]
θ2 = tan ^-1 (23/100) = 12.9 °
[0067]
FIG. 5 shows the color reproduction range when the color separation angle is θ2 (this embodiment) and the color reproduction range when the color separation angle is θ1 (comparative example).
[0068]
As can be seen from FIG. 5, the color purity (color reproduction range) of the R light beam is greatly improved when the color separation angle is θ2 (this embodiment). In the present embodiment, with respect to the G and B lights, the color mixture is slightly increased and the chromaticity shift occurs, but it is very small and does not substantially reduce the display quality.
[0069]
In this embodiment, the distance Da between the R focused spot and the G focused spot and the distance Db between the R focused spot and the B focused spot are set 2 μm larger (23 μm) than the pitch P of the pixel openings.
[0070]
The width Wb (including the video line width and the black matrix) of the light shielding portion of the liquid crystal display element 108 used here is 3 μm, and the bonding error between the counter substrate on which the microlens array 107 is formed and the TFT substrate is 1 μm. The total of the above 2 μm is set to match 3 μm of the light shielding portion width Wb. That is, the distances Da and Db between the focused spots are set so that the B light beam and the G light beam do not directly enter the adjacent pixel opening even when the bonding error is taken into consideration.
[0071]
The above-described liquid crystal display device 100 according to the embodiment of the present invention can realize a brighter display with a wider color reproduction range than a conventional liquid crystal display device.
[0072]
In this embodiment, since the UHP lamp having a weak spectral intensity of the R light beam is used, the interval (Da and Db) between the G light beam and the B light beam is determined with respect to the R light beam condensing spot that is most affected by the color mixture. When a lamp having a different spectral intensity ratio such as a halogen lamp or a xenon lamp is used, the other two color beams are used for the condensed light beam having the weakest spectrum intensity. If the condensing spot is adjusted to be larger than the pixel opening pitch, the same effect as in the above embodiment can be obtained. For example, when a halogen lamp is used, since the spectral intensity of the B light beam is weaker than the other two color light beams, a condensing spot of the B light beam is formed at the pixel opening in the center of the pixel, and the condensing spot of the B light beam What is necessary is just to adjust the space | interval of the condensing spot of G light flux and R light flux with respect to the pixel opening part pitch.
[0073]
Further, in the above embodiment, the color separation angles of both the R and G light beams and the R and B light beams are adjusted so that both the G light condensing spot and the B light condensing spot are 23 μm from the R light condensing spot. Although arranged at intervals, only one of the G condensing spot and the B condensing spot is arranged at an interval larger than the pixel opening pitch P, or the R condensing spot, the G condensing spot, and the interval Da. Even if the distance Db between the R condensing spot and the B condensing spot is different (Da ≠ Db), the effect of the present invention can be obtained.
[0074]
In the above embodiment, the condensing spot of the microlens 107 is set to be formed on the pixel opening of the liquid crystal display element 108, but the condensing spot is displayed on the liquid crystal display in consideration of matching with the projection lens. You may set so that it may come to the projection lens side rather than the pixel opening part of the element 108. FIG. Even in this case, the effect of the present invention can be obtained by adjusting the intervals between the condensed spots of the R light beam, the G light beam, and the B light beam at the position of the pixel opening.
[0075]
Further, in the above embodiment, the configuration in which one microlens array 107 is arranged on the light incident side of the liquid crystal display element 108 is exemplified. However, for example, as shown in FIGS. The microlens array may be used. Further, a microprism array can be used instead of the microlens array. In FIGS. 6A and 6B, only the chief rays of the respective color beams are shown.
[0076]
The optical element 50 shown in FIG. 6A includes a first microlens array 52 including a first microlens 52a, and a second microlens array 54a including a second microlens array 54a arranged one-on-one with the first microlens 52a. And a microlens array 54. The first macro lens array 52 is formed on the base substrate 51, and the second micro lens array 54 is formed on the light condensing side of the first micro lens array 52 via the intermediate substrate 53. A transparent substrate (cover glass) 55 is provided on the light emission side (liquid crystal display element side) of the second microlens array 54. The light beams collected by the first microlens array 52 are collimated by the second microphone lens array 54 and guided to the corresponding pixel openings.
[0077]
The optical element 60 shown in FIG. 6B has a microlens array 62 including microlenses 62a and a microprism array 64 including microphone prisms 64a arranged one-on-one with the microlenses 62a. The macro lens array 62 is formed on the base substrate 61, and the micro prism array 64 is formed on the light condensing side of the micro lens array 62 via the intermediate substrate 63. A transparent substrate (cover glass) 65 is provided on the light emitting side (liquid crystal display element side) of the microprism array 64. The light beams collected by the microlens array 62 are collimated by the microphone prism array 64 and guided to the corresponding pixel openings. The microprism 64a has inclined surfaces a and b and a center portion (a flat portion having a top surface parallel to the main surface of the microprism array 60) c therebetween. The principal rays of the light beam incident on the inclined surfaces a and b from the corresponding microlenses 62a are refracted by the inclined surfaces a and b on both sides, and are made substantially parallel to the principal ray of the light beam incident on the center portion c.
[0078]
When the optical element 50 or 60 shown in FIGS. 6A and 6B is used, the R, G, and B light beams are incident on the liquid crystal display element at the same angle. They can be set together, and the contrast ratio of the display can be improved. Further, for example, in the configuration using the microlens array 107 shown in FIG. 2, the G and B light beams incident obliquely have a larger exit angle than the R light beam after passing through the liquid crystal display element. However, when the optical element 50 or 60 is used, the G and B light fluxes are all eliminated and the screen reaches the screen, and the brightness can be improved.
[0079]
【The invention's effect】
According to the present invention, the influence of color mixing (stray light) due to the aberration of a condensing element such as a microlens can be suppressed, the color reproduction range can be expanded, and a pixel display device with excellent display quality can be provided. .
[0080]
A color light beam having the weakest spectral intensity among a plurality of color light beams (for example, R, G, and B light beams) incident on the image display element is made to correspond to the pixel opening located in the center of the pixel, and the other color light beams are condensed. The distance between the center of the spot (center of the center pixel aperture) and the center of the focused spot of the color beam with the weakest spectral intensity is more than the arrangement pitch of the pixel apertures of the image display element, thereby reducing the influence of color mixing. The chromaticity of the color received larger can be improved, and the color reproduction range can be further expanded.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of a projection type color liquid crystal display device 100 according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a light collecting element group 107 and a liquid crystal display element 108 in the liquid crystal display device 100. FIG.
FIG. 3 is a schematic diagram showing a positional relationship between color light flux condensing spots 12R, 12G, and 12B and pixel openings 108R, 108G, and 108B in the liquid crystal display device 100. FIG.
4 is a schematic diagram for explaining a function of a micro lens 107a in the liquid crystal display device 100. FIG.
FIG. 5 is a CIE chromaticity diagram for explaining a color reproduction range of a liquid crystal display device.
6A and 6B are cross-sectional views schematically showing the structure of an optical element including a microlens used in a liquid crystal display device according to an embodiment of the present invention.
FIG. 7 is a schematic diagram for explaining a method of manufacturing a microlens used in the liquid crystal display device according to the embodiment of the present invention.
FIG. 8 is a schematic diagram for explaining a mechanism of color mixing in a conventional projection type image display apparatus.
FIGS. 9A and 9B are diagrams for explaining the relationship between the degree of color mixing and the color reproduction range, and FIG. 9A is a CIE chromaticity diagram for a conventional liquid crystal display device; b) is a CIE chromaticity diagram for the liquid crystal display device of the present embodiment.
[Explanation of symbols]
12R, 12G, 12B Colored light condensing spot
101 Light source
102 Parabolic mirror (reflector)
103 fly eye lens
104 Field lens
105 field lens
106 Dichroic mirror
107 Micro lens array
108 Liquid crystal display element
108R, 108G, 108B Pixel opening
109 Projection lens
110 screens

Claims (7)

A light source;
A color separation element that separates the luminous flux emitted from the light source into first, second, and third color luminous fluxes in different wavelength ranges and emits the luminous fluxes at different angles;
A light-shielding portion, and first, second, and third pixel openings that are separated from each other by the light-shielding portion, and the second and third pixel openings sandwich the first pixel opening therebetween. A plurality of pixels composed of the first, second and third pixel openings arranged at a predetermined pitch on a straight line along a predetermined direction as described above,
A plurality of condensing elements provided one-on-one with respect to the plurality of pixels between the color separation element and the image display element;
The first, second, and third focused spots on the surfaces defined by the plurality of pixels of the first, second, and third color light fluxes that have passed through the plurality of focused elements, respectively. Then, the center of the first focused spot is formed in the first pixel opening, the center of the second focused spot is formed in the second pixel opening, and the center of the third focused spot is The center is formed in the third pixel opening,
The distance (Da) between the center of the first focused spot and the center of the second focused spot in the predetermined direction and the distance between the center of the first focused spot and the center of the third focused spot ( An image display device in which at least one interval (D) of Db) is larger than the predetermined pitch (P). The image display device according to claim 1, wherein a center of the first focused spot is formed at a center of the first pixel opening. 3. The image display device according to claim 1, wherein a spectral intensity of the first color light beam is weaker than a spectral intensity of the second and third color light beams. The image display device according to claim 3, wherein the first color light beam is a red light beam. 5. The image display device according to claim 1, wherein each of the plurality of condensing elements is a microlens and forms a two-dimensional microlens array. The width (Ws) in the predetermined direction of the first, second and third focused spots is substantially equal to the width (Wp) in the predetermined direction of the first, second and third pixel openings, The image display device according to claim 1. When the width of the light shielding portion in the predetermined direction is Wb, the at least one interval (D) is:
P <D <P + Wb
The image display device according to claim 6, wherein the relationship is satisfied.

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