BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a display apparatus which displays color image on
a large screen by using a large number of luminous picture elements disposed in correspondence
with a plurality of luminous colors.
Description of Related Art
[0002] Fig. 1 designates a perspective view of a conventional display apparatus disclosed
in the Japanese Patent Application Laid-Open No. 64-2086 of 1989 for example. The
reference numeral 11 shown in Fig. 1 designates a display unit, in which a plurality
of luminous picture elements 21 including red picture element 2R, green picture element
2G, and blue picture element 2B, are respectively disposed in parallel with each other
in matrix formation. A number of spacers 31 are provided between those adjoining luminous
picture elements 21. In addition, a magnifying unit 41 is disposed in front of the
display unit 11. The magnifying unit 41 includes a plurality of convex lenses 51 in
matrix formation, each of which corresponds to each of luminous picture elements 21.
[0003] Next, functional operation of this conventional display apparatus is described below.
Each of these luminous picture elements 21 is driven by a driving system (not shown)
to emit each own color beam. As a whole, these luminous picture elements 21 are disposed
at equal intervals. Assume that the interval (in other words, width of the spacer
31) is expressed in terms of P22. Speaking of a large-screen display apparatus, this
display apparatus may be composed of a plurality of display units 11 shown in Fig.
1 in alignment with each other. In order to precisely dispose these luminous picture
elements 21 at equal intervals, it is essential for this display apparatus to provide
the spacer width P22 which is more than double the edge-directional distance P23 between
the most peripheral luminous the blue picture element 21 and the wall edge of the
display unit 11. While operating a large-screen display apparatus, luminosity of each
luminous picture element 21 is controlled in order that the luminosity can always
remain proportional to the amplitude of television signals. Although these luminous
picture elements 21 are discretely aligned at the predetermined intervals, viewers
can properly recognize the continuously running television image when they watch the
display unit 11 across an adequate distance.
[0004] Now, in order to secure high resolution of the image on a large-screen display, it
is essential for the display apparatus to increase the number of those luminous picture
elements 21 per unit area. In other words, it is essential for the system to contract
the distance P21 between the center positions of the adjoining luminous picture elements
21. Nevertheless, as mentioned earlier, the display unit 11 must provide the spacer
width P22 which is more than double the edge-directional distance P23, and yet, since
the edge-directional distance P23 is substantially the wall thickness of the display
unit 11, there is a definite limit to thin the edge-directional distance P23 furthermore.
As a result, in order to increase the number of the luminous picture elements 21 per
unit area, the dimension of these luminous picture elements 21 must be contracted.
In other words, the finer the resolution of the image on display, the less the area
ratio available for illumination. When this condition is present, it merely results
in the emphasized discontinuity of the discretely aligned luminous picture elements
21. In consequence, image quality degrades itself to cause viewers to feel rough quality
of image on the TV screen.
[0005] To prevent this adverse effect, there is an idea of providing the magnifying unit
41 in front of the display unit 11 like the one shown in Figs. 1 and 2. For example,
a plurality of convex lenses 51 are provided in front of the corresponding luminous
picture elements 21 by way of setting the center positions of those luminous picture
elements 21 in perfect accord with the center positions of these convex lenses 51
in order to apparently expand the luminous area ratio so that image quality can eventually
be improved. When implementing this method, as shown in Fig. 3, when looking at those
luminous picture elements 21 through the magnifying unit 41, the distance P21 between
the centers of the adjoining luminous picture elements 21 is equal to the distance
P41 between the centers of the adjoining convex lenses 51. Nevertheless, the apparent
interval P42 between those luminous picture elements 21 is shorter than the original
interval P22 between those luminous picture elements 21.
[0006] Fig. 4 designates another structure of the conventional display unit 11 in which
those luminous picture elements 2 substantially composed of an independent red picture
element R, or an independent green picture element G, or an independent blue picture
element B, are aligned with each other. Even when using this structure, based on the
reason cited above, it is also essential for the display unit 11 to provide the spacer
width P22 which is more than double the edge-directional distance P23. In consequence,
the finer the resolution of image on display, the narrower the area of each luminous
picture element 2 as shown in Fig. 5, thus resulting in the lowered luminosity.
[0007] There is the structure of a display unit 1 designed for preventing luminosity from
lowering itself as shown in Fig. 6, which contracts the distance P1 between two adjoining
luminous picture elements in a group including four luminous picture elements to be
shorter than the distance P2 between adjoining groups. This system is disclosed in
the Japanese Utility Model Application Laid-Open No. 63-174377 of 1988. This system
provides each spacer width P22 which is more than double the edge-directional distance
P23, and yet, contracts the distance between adjoining luminous picture elements 2
of each group nit to be shorter than the distance between a luminous picture element
2 belonging to a group and a luminous picture element 2 belonging to the other adjoining
group in order that the area of these luminous picture elements 2 can be expanded
from the area of those luminous picture elements 2 shown in Fig. 5. In this way, when
constructing one group of four luminous picture elements 2 and expanding the area
of luminous picture elements 2, those luminous picture elements 2 are necessarily
disposed by applying uneven pitch containing deviation in the link and row directions
every two luminous picture elements. As a result, this structure usefully promotes
luminosity, but instead, it lowers image quality, and thus, there is a definite limit
in the possibility of expanding the area of each luminous picture element 2 even when
composing a display apparatus based on this art.
[0008] Concretely, when the distance P1 between those luminous picture elements 2 and the
distance P2 between those groups mentioned above are expressed by a relationship P1/P2
= 1, all the luminous picture elements 2 are properly disposed according to the equal
pitch as shown in Figs. 4 and 5. The relationship between P1 and P2 shown in Fig.
6 approximately corresponds to P1/P2 = 0.7. On the other hand, the relationship between
P1 and P2 shown in Fig. 7 approximately corresponds to P1/P2 < 0.6. The test result
proves that there is a definite limit in the image quality when there is a relationship
P1/P2 = 0.65. Taking these factors into account, the system of aligning the luminous
picture elements 2 shown in Fig. 6 is dominantly useful in the promotion of luminosity
rather than such an adverse effect in the degradation of image quality. Nevertheless,
although the system shown in Fig. 7 for the alignment of luminous picture elements
2 more effectively promotes luminosity, it is by no means suited for practical application.
[0009] Any of those conventional display apparatuses incorporates any of those structures
cited above. Nevertheless, since the conventional display apparatus respectively expands
apparent luminous areas by applying the magnifying unit 41 by way of disposing all
the luminous picture elements 21 based on the equal pitch, the actual luminous areas
are not substantially expanded at all. As a result, luminosity cannot fully be promoted.
In consequence, the conventional display apparatus can effectively be made available
in bright environments like a rail-road station or an airport where a large number
of passengers assemble. On the other hand, if the conventional display apparatus is
compulsorily provided with intensified luminosity, excessive power like extremely
high energy will be given to those luminous picture elements 21, thus quickly dissipating
the service life of the display unit 11.
[0010] On the other hand, the conventional display apparatus disposing the luminous picture
elements 2 based on uneven pitch is obliged to expand the areas of those luminous
picture elements 2 for the sake of enhancing luminosity. This in turn means that the
wider the areas of those luminous picture elements 2, the poorer the image quality
in consequence. Because of this reason, the conventional display apparatus can practically
expand the area ratio beyond a certain limit. This in turn involves critical problem.
SUMMARY OF THE INVENTION
[0011] An object of the invention is to provide a novel display apparatus that can securely
provide highly intensified luminosity by substantially expanding areas of the luminous
picture elements.
[0012] Another object of the invention is to provide a novel display apparatus that can
securely provides extremely smooth color image by effectively preventing image quality
from incurring degradation at all.
[0013] A still further object of the invention is to provide a novel display apparatus that
can securely protect durable service life of the display unit.
[0014] The invention provides a novel display apparatus available for displaying stable
color image on a large screen. The display apparatus embodied by the invention incorporates
a large number of luminous picture elements which are disposed in matrix formation.
Of those many luminous picture elements, each four elements adjoining each other in
the link and row directions are constructed into a group. The display apparatus embodied
by the invention characteristically comprises the following; a display unit in which
the distance between those adjoining luminous picture elements in each group is substantially
shorter than the distance between those adjoining luminous picture elements belonging
to adjoining groups; and a magnifying unit which is disposed in front of the display
unit, wherein the magnifying unit further magnifies light beam emitted from each luminous
picture element in the direction of those adjoining luminous picture elements belonging
to adjoining groups than in the direction of those luminous picture elements adjoining
each other in a group to which it belongs.
[0015] The magnifying unit provided for the display apparatus embodied by the invention
apparently approximates the ratio (P1/P2) between the distance P1 between each luminous
picture element and the distance P2 between each group to the value 1. In consequence,
even though the display apparatus actually has an insignificant value of the ratio
P1/P2, image quality can remain stable without incurring degradation at all.
[0016] The above and further objects and features of the invention will more fully be apparent
from the following detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
Fig. 1 is a perspective view of a conventional display apparatus;
Fig. 2 is a sectional view of the conventional display apparatus shown in Fig. 1;
Fig. 3 is explanatory of the magnifying effect of the magnifying unit shown in Fig.
1;
Figs. 4 and 5 respectively designate the arrangement of independent luminous picture
elements;
Figs. 6 and 7 respectively designate the arrangement of luminous picture elements
when constructing four luminous picture elements into a group;
Fig. 8(a) is a sectional view of the display apparatus according to an embodiment
of the invention;
Fig. 8(b) is the magnified condition of the luminous picture elements when using the
magnifying unit shown in Fig. 8(a); and
Fig. 9 is a sectional view of the display apparatus according to another embodiment
of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Referring now more particularly to the accompanying drawings, the display apparatus
according to an embodiment of the invention is described below. First, refer to Fig.
8(a) which designates the sectional view of the display apparatus embodied by the
invention. The reference numeral 1 designates a display unit, 2 designates a large
number of luminous picture elements consisting of red, green or blue independent picture
elements, and 4 designates a magnifying unit in which a large number of convex lenses
5 are aligned in correspondence with respective luminous picture elements 2. Fig.
8(b) designates the magnified condition of light beam emitted from those luminous
picture elements 2 when viewers look at the front of the magnifying unit 4.
[0019] Next, functional operation of the display apparatus embodied by the invention is
described below. A number of luminous picture elements 2 disposed in the display unit
1 according to the arrangement shown in Fig. 1 for example. Fig. 7 shows the arrangement
in which each four luminous picture elements 2 conjunctionally make up a group, and
yet, the red picture element R, green picture element G, and the blue picture element
B, are disposed according to the predetermined composition ratio 1:2:1. Furthermore,
less than 0.6 is provided for the ratio P1/P2 between the inter-element distance P1
between those luminous picture elements adjoining each other in each group and the
inter-group distance P2 between those adjoining luminous picture elements belonging
to adjoining groups. As mentioned earlier, when introducing the above arrangement
based on less than 0.6 of the ratio P1/P2, image quality significantly lowers.
[0020] To prevent this, the display apparatus embodied by the invention is provided with
a number of convex lenses 5 in front of corresponding luminous picture elements 2,
and yet, as shown in Fig. 8(a), the center "r" of each convex lens 5 deviates from
the center "p" of each corresponding luminous picture element 2 by an amount ΔP in
the direction of the center of each group. Because of this arrangement, light beam
emitted from each luminous picture element 2 is magnified further in the direction
of the adjoining groups. By properly establishing the value ΔP or the magnification
of each convex lens 5, it is possible for the display apparatus of the invention to
apparently materialize the ratio P1/P2 = 1. Since the display apparatus of the invention
achieves the above arrangement, as shown in Fig. 8(b), when looking at the magnifying
unit 4 from the front, viewers can witness a number of magnified luminous picture
elements 2a containing the ratio P1/P2 which is closer to the value 1 than the actual
ratio value present in the display unit 1. In consequence, the display apparatus embodied
by the invention can securely prevent the image quality from adversely being affected
by uneven pitch, and yet, effectively promotes image resolution availing of properly
magnified areas of the aligned luminous picture elements. Furthermore, the display
apparatus embodied by the invention apparently materializes substantial magnification
of luminous area more than that is normally generated by any conventional display
apparatus.
[0021] The above description has solely referred to an embodiment in which the display unit
1 contains 1:2:1 of the composition ratio of the R.G.B. components in a group of four
luminous picture elements 2. Nevertheless, the embodiment of the invention may also
use such a composition ratio based on any value other than the one specified above.
Furthermore, not only those three primary colors, but the display unit 1 embodied
by the invention may also use mono-chromatic composition as well.
[0022] The above description has also solely referred to the use of those convex lenses
5. Nevertheless, as shown in Fig. 9, another embodiment of the invention allows light
beam emitted from those luminous picture elements 2 to be magnified furthermore in
the direction of the adjoining groups by introducing a number of photoconductors 5a
like optical fibers in place of those convex lenses 5. This system securely provides
quite satisfactory magnifying affect exactly identical to that is achieved by the
preceding embodiment.
[0023] As is clear from the above description, the display apparatus embodied by the invention
disposes a large number of luminous picture elements in the display unit by way of
contracting the distance between those luminous picture elements to be shorter than
the distance between groups, and yet, provides the magnifying unit such like convex
lenses in order that the distance between adjoining luminous picture elements can
apparently appromate the distance between adjoining groups. By virtue of these unique
arrangements, the display apparatus embodied by the invention can securely promote
luminosity by effectively applying magnified luminous areas, and yet, the display
apparatus stably provides fine and smooth image without causing image quality to degrade,
while effectively promoting own service life to a great extent.
1. A display apparatus comprising:
a display unit incorporating a plurality of luminous picture elements disposed
in matrix formation, wherein the distance between those luminous picture elements
in each group is shorter than the distance between those luminous picture elements
belonging to adjoining groups, said group being composed of a number of luminous picture
elements adjoining themselves in the line and row directions; and
a magnifying unit which further magnifies light beam emitted from each of said
luminous picture elements in the direction of those adjoining luminous picture elements
belonging to adjoining groups than in the direction of those adjoining luminous picture
elements in the group to which said luminous picture element belongs.
2. A display apparatus according to Claim 1, wherein said magnifying unit comprises a
plurality of magnifying elements which are respectively disposed in confrontation
with said luminous picture elements, wherein each of said plurality of magnifying
units further magnifies light beam emitted from each of said plurality of luminous
picture elements in the direction of those adjoining luminous picture elements belonging
to adjoining groups than in the direction of those adjoining luminous picture elements
in the group to which said luminous picture element belongs.
3. A display apparatus according to Claim 2, wherein said plurality of magnifying elements
are a plurality of convex lenses.
4. A display apparatus according to Claim 3, wherein the center of each convex lens deviates
in the direction of the center of the group to which the corresponding luminous picture
element belongs from the center of the corresponding luminous picture element.
5. A display apparatus according to Claim 2, wherein said plurality of magnifying elements
are a plurality of optical fibers.
6. A display apparatus according to Claim 1, wherein of those luminous picture elements,
four luminous picture elements adjoining each other in the line and row directions
conjunctionally make up the group.
7. A display apparatus according to Claim 6, wherein said group is composed of a red
luminous picture element, two of green luminous picture elements, and a blue luminous
picture element.