A liquid crystal display includes an illumination optical system which has a light source for emitting light and acts to irradiate the light from the light source on a light bulb on which an optical image is formed in accordance with a video signal, and a transmission-type liquid crystal display element for displaying the image information by the electrooptical effect of the liquid injected between a pair of transparent substrates of the light bulb. The liquid crystal display element is formed of a micro-lens array which has unit lenses provided to oppose the respective picture elements of the picture element array of the liquid crystal and thus to have the same array as the picture element array of the liquid crystal. Since this micro-lens array is closely attached to the side of liquid crystal display element to which the luminous flux emitted from the light source is incident, or integrally formed within the liquid crystal cell substrate, the liquid crystal display element has a high aperture ratio.
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20. A liquid crystal display comprising:
a transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident transparent substrate is proximate, at its front surface, with a flat-plate microlens array which has regions of unit lenses so that said regions respectively oppose the picture elements of the picture element array of said liquid crystal; an illumination optical system; and a light source having a light emitting element of a shape substantially similar to a shape of an aperture of said picture element of the liquid crystal display element in a cross-section perpendicular to the optical axis of said illumination optical system.
22. A liquid crystal display comprising:
a transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident transparent substrate is proximate, at its front surface, with a flat-plate microlens array which has regions of unit lenses, said regions corresponding in shape to a shape of picture elements of said liquid crystal so that said regions respectively oppose the picture elements of the picture element array of said liquid crystal; an illumination optical system; and a light source having a light emitting element of a shape substantially similar to a shape of an aperture of said picture element of the liquid crystal display element in a cross-section perpendicular to the optical axis of said illumination optical system.
0. 35. A display, comprising:
a display element which allows display of picture information by an electrooptical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element and has regions acting as unit lenses arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element; a drive circuit which drives said display element according to a picture information signal; a projection lens which magnifies and projects said picture information of said display element onto a screen; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements, and being arranged so that a shape of luminous flux through each region of said unit lenses, relative to a cross-section perpendicular to an optical axis, is substantially rectangular around where an image of said light source is formed.
17. A liquid crystal display element in which liquid crystal is injected into a pair of transparent substrates having picture elements defined therein for displaying picture information by utilizing a electrooptic effect of liquid crystal, comprising:
a flat-plate microlens array disposed in one of a close contact with and integrated with a transparent substrate at a beam incident side of said liquid crystal display element, a focal point of each unit lens of said flat-plate microlens array being coincident substantially with said liquid crystal and having a rectangular shape, wherein, if an angle of an incident light in one of said picture elements relative to an optical axis of said unit lens is θ, and a distance from a back-side principal point of said unit lens to said liquid crystal surface is d, the following relation is satisfied,
where D is a diagonal length of a picture element electrode within the region corresponding to one picture element, and n is a refractive index of the medium from said micro-lens array to said liquid crystal surface.
0. 31. A liquid crystal display, comprising:
a liquid crystal display element which allows display of picture information by an electrooptical effect of a liquid crystal as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said liquid crystal, and said flat-plate micro-lens array has regions acting as unit lenses arranged in the same manner as picture elements of said liquid crystal so that ones of said regions respectively oppose ones of the picture elements of said liquid crystal display element; a drive circuit which drives said liquid crystal display element according to a picture information signal; an illumination optical system which has a concave mirror which acts to direct luminous flux from a light source toward said liquid crystal display element, through said unit lenses to said picture elements, and being arranged so that a shape of said concave mirror relative to a cross-section perpendicular to an optical axis of said illumination optical system is substantially similar to that of an aperture of a picture element of said liquid crystal display element.
0. 30. A display, comprising:
a display element which allows display of picture information by an electro-optical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element, and said flat-plate micro-lens array has regions acting as unit lenses which each region has a substantially rectangular shape and is arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element; a drive circuit which drives said display element according to a picture information signal; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements, and being arranged so that a shape of the luminous flux relative to a cross-section perpendicular to an optical axis of said illumination optical system is substantially similar to that of a light control region of said picture element of said display element; a projection lens which magnifies and projects said picture information of said display element onto a screen.
24. A liquid crystal display element in which liquid crystal is injected into a pair of transparent substrates having picture elements defined therein for displaying picture information by utilizing a electrooptic effect of liquid crystal, comprising:
a flat-plate microlens array disposed in one of a close contact with and integrated with a transparent substrate at a beam incident side of said liquid crystal display element, a focal point of each unit lens of said flat-plate microlens array being coincident substantially with said liquid crystal and each unit lens having a rectangular shape, wherein said flat-plate micro-lens array and said liquid crystal display element are provided tilted at an angle with respect to an angle of incident light, and wherein, if an angle of an incident light in one of said picture elements relative to an optical axis of said unit lens is θ, and a distance from a back-side principle point of said unit lens to said liquid crystal surface is d, the following relation is satisfied,
where D is a diagonal length of a picture element electrode within the region corresponding to one picture element, and n is a refractive index of the medium from said microlens array to said liquid crystal surface.
0. 38. An optical system unit for a display, comprising:
a display element which allows display of picture information by an electrooptical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element and said flat-plate micro-lens array has regions acting as unit lenses arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element, each region of said regions of unit lenses has a substantially similar shape to each corresponding region of said picture elements and has an image forming operation; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements; a projection lens which magnifies and projects said picture information of said display element onto a screen; wherein said each region of unit lenses makes said luminous flux have an approximately same cross-section area as each light control region of said picture elements of said display element around said light control region, when an un-parallel incident light is supplied to said each region of said regions of unit lenses from said illumination optical system.
18. A liquid crystal display comprising:
a transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident transparent substrate is proximate, at its front surface, with a flat-plate micro-lens array which has regions of unit lenses, said regions corresponding in shape to a shape of picture elements of said liquid crystal so that said regions respectively oppose the picture elements of the picture element array of said liquid crystal, and which, if one side and the other side of a flat shape of one of said picture elements are represented by L1 and L2, respectively, satisfies the following conditions, when L1<L2, π(L1/2)2<S≦L1L2, when L1=L2, π(L1/2)2<S≦L12, where S is the area of the region acting as said unit lens, and the focal point of each unit lens is coincident substantially with said liquid crystal and center of a corresponding picture element, an illumination optical system; and a light source having a light emitting element of a shape substantially similar to a shape of an aperture of said picture element of the liquid crystal display element in a cross-section perpendicular to the optical axis of said illumination optical system.
25. A liquid crystal display element in which liquid crystal is injected into a pair of transparent substrates having picture elements defined therein for displaying picture information by utilizing a electrooptic effect of liquid crystal, comprising:
a flat-plate micro-lens array disposed in one of a close contact with and integrated with a transparent substrate at a beam incident side of said liquid crystal display element, a focal point of each unit lens of said flat-plate micro-lens array being coincident substantially with said liquid crystal and each unit lens having a rectangular shape, wherein said flat-plate micro-lens array and said liquid crystal display element are provided tilted at an angle with respect to a main axis of incident light such that said main axis of incident light substantially does not parallel a perpendicular axis extending from a main plane of said liquid crystal display element, and wherein, if an angle of an incident light in one of said picture elements relative to an optical axis of said unit lens is θ, and a distance from a back-side principle point of said unit lens to said liquid crystal surface is d, the following relation is satisfied,
where D is a diagonal length of a picture element electrode within the region corresponding to one picture element, and n is a refractive index of the medium from said micro-lens array to said liquid crystal surface.
16. A transmission-type liquid crystal display element for displaying picture information by the electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident transparent substrate is integral with a flat-plate micro-lens array which has regions of unit lenses, each of said regions of unit lenses having a rectangular shape and respectively opposing one of the picture elements of the picture element array of said liquid crystal, and which, if one side and the other side of a flat shape of one of said picture elements are represented by L1 and L2, respectively, satisfies the following conditions,
when L1<L2, π(L1/2)2<S≦L1·L2, when L1=L2, π(L1/2)2<S≦L12, where S is the area of the region acting as said unit lens, and the focal point of each unit lens is coincident substantially with the surface of said liquid crystal, and if the angle of incident light to the surface of said liquid crystal is α and the distance from the back-side principal point of said unit lens to the surface of said liquid crystal is d, the optical axis of each of said unit lenses and a center of a corresponding picture element are displaced by a predetermined amount, y, expressed by the following equation, in accordance with the incident angle of said incident light,
where n is the refractive index of the medium from said micro-lens array to the surface of said liquid crystal.
15. A transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident transparent substrate is proximate, at its front surface, with a flat-plate micro-lens array which has regions of unit lenses, each of said regions of unit lenses having a rectangular shape and respectively opposing one of the picture elements of the picture element array of said liquid crystal, and which, if one side and the other side of a flat shape of one of said picture elements are represented by L1 and L2, respectively, satisfies the following conditions,
when L1<L2, π(L1/2)2<S≦L1·L2, when L1=L2, π(L1/2)2<S≦L12, where S is the area of the region acting as said unit lens, the focal point of each unit lens is coincident substantially with said liquid crystal, and if the angle of incident light to the surface of said liquid crystal is α and the distance from a back-side principal point of said unit lens to the surface of said liquid crystal is d, the optical axis of each of said unit lenses and a center of a corresponding picture element are displaced by a predetermined amount, y, expressed by the following equation, in accordance with the incident angle of said incident light,
where n is the refractive index of the medium from said micro-lens array to the surface of said liquid crystal.
0. 39. An optical system unit for a display, comprising:
a display element which allows display of picture information by an electrooptical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element and said flat-plate micro-lens array has regions acting as unit lenses arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element, each region of said regions of unit lenses has a substantially similar shape to each corresponding region of said picture elements and has an image forming operation; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements; a projection lens which magnifies and projects said picture information of said display element onto a screen; wherein said each region of unit lenses makes said luminous flux have an approximately same cross-section area as each light control region of said picture elements of said display element around said light control region, when an un-parallel incident light is supplied to said each region of said regions of unit lenses from said illumination optical system; and wherein said illumination optical system has a concave mirror, and is arranged so that a shape of said concave mirror relative to a cross-section perpendicular to an optical axis is substantially similar to that of an aperture of a picture element of said display element.
0. 40. An optical system unit for a display, comprising:
a display element which allows display of picture information by an electrooptical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element and said flat-plate micro-lens array has regions acting as unit lenses arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element, each region of said regions of unit lenses has a substantially similar shape to each corresponding region of said picture elements and has an image forming operation; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements; a projection lens which magnifies and projects said picture information of said display element onto a screen; wherein said each region of unit lenses makes said luminous flux have an approximately same cross-section area as each light control region of said picture elements of said display element around said light control region, when an un-parallel incident light is supplied to said each region of said regions of unit lenses from said illumination optical system; and wherein said illumination optical system has a concave mirror and a reflecting mirror, and is arranged so that a shape of said luminous flux relative to a cross-section perpendicular to an optical axis is substantially similar to that of said aperture of said picture element.
0. 36. A display, comprising:
a display element which allows display of picture information by an electrooptical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element and said flat-plate micro-lens array has regions acting as unit lenses arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element, each region of said regions of unit lenses has a substantially similar shape to each corresponding region of said picture elements and has an image forming operation; a drive circuit which drives said display element according to a picture information signal; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements; a projection lens which magnifies and projects said picture information of said display element onto a screen; wherein said each region of unit lenses makes said luminous flux have an approximately same cross-section area as each light control region of said picture elements of said display element around said light control region when an un-parallel incident light is supplied to said each region of said regions of unit lenses from said illumination optical system; and wherein said illumination optical system has a concave mirror, and is arranged so that a shape of said concave mirror relative to a cross-section perpendicular to an optical axis is substantially similar to that of an aperture of a picture element of said display element.
0. 37. A display, comprising:
a display element which allows display of picture information by an electrooptical effect of a picture element as a light valve, wherein a flat-plate micro-lens array is formed at least in a light-incident side against said picture element and said flat-plate micro-lens array has regions acting as unit lenses arranged in the same manner as picture elements so that ones of said regions respectively oppose ones of the picture elements of said display element, each region of said regions of unit lenses has a substantially similar shape to each corresponding region of said picture elements and has an image forming operation; a drive circuit which drives said display element according to a picture information signal; an illumination optical system which directs a luminous flux from a light source toward said display element, through said unit lenses to said picture elements; a projection lens which magnifies and projects said picture information of said display element onto a screen; wherein said each region of unit lenses makes said luminous flux have an approximately same cross-section area as each light control region of said picture elements of said display element around said light control region when an un-parallel incident light is supplied to said each region of said regions of unit lenses from said illumination optical system; and wherein said illumination optical system has a concave mirror and a reflecting mirror, and is arranged so that a shape of said luminous flux relative to a cross-section perpendicular to an optical axis is substantially similar to that of said aperture of said picture element.
26. A transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident transparent substrate is proximate, at its front surface, with a flat-plate micro-lens array which has regions of unit lenses, each of said regions of unit lenses having a rectangular shape and respectively opposing one of the picture elements of the picture element array of said liquid crystal, and which, if one side and the other side of a flat shape of one of said picture elements are represented by L1 and L2, respectively, satisfies the following conditions,
when L1<L2, π(L1/2)2<S≦L1L2, when L1=L2, π(L1/2)2<S≦L12, where S is the area of the region acting as said unit lens, the focal point of each unit lens is coincident substantially with said liquid crystal, and wherein said flat-plate micro-lens array and said liquid crystal display element are provided tilted at an angle with respect to a main axis of incident light such that said main axis of incident light substantially does not parallel a perpendicular axis extending from a main plane of said liquid crystal display element, and if the angle of incident light to the surface of said liquid crystal is α and the distance from a back-side principle point of said unit lens to the surface of said liquid crystal is d, the optical axis of each of said unit lenses and a center of a corresponding picture element are displaced by a predetermined amount, Y, expressed by the following equation, in accordance with the incident angle of said incident light,
where n is the refractive index of the medium from said micro-lens array to the surface of said liquid crystal.
28. A transmission-type liquid crystal display element for displaying picture information by the electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light incident transparent substrate is integral with a flat-plate micro-lens array which has regions of unit lenses, said regions corresponding in shape to a shape of picture elements of said liquid crystal so that said regions respectively oppose the picture elements of the picture element array of said liquid crystal, and which, if one side and the other side of a flat shape of one of said picture elements are represented by L1 and L2, respectively, satisfies the following conditions,
when L1<L2, π(L1/2)2<S≦L1L2, when L1=L2, π(L1/2)2<S≦L12, where S is the area of the region acting as said unit lens, and the focal point of each unit lens is coincident substantially with the surface of said liquid crystal, and wherein said flat-plate micro-lens array and said liquid crystal display element are provided tilted at an angle with respect to a main axis of incident light such that said main axis of incident light substantially does not parallel a perpendicular axis extending from a main plane of said liquid crystal display element, and if the angle of incident light to the surface of said liquid crystal is α and the distance from the back-side principle point of said unit lens to the surface of said liquid crystal is d, the optical axis of each of said unit lenses and a center of a corresponding picture element are displaced by a predetermined amount, Y, expressed by the following equation, in accordance with the incident angle of said incident light,
where n is the refractive index of the medium from said micro-lens array to the surface of said liquid crystal.
0. 1. A transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident side of one of said transparent substrates is closely attached at its front surface, with a flat-plate micro-lens array which has regions of unit lenses arranged in the same manner as the picture elements of said liquid crystal so that said regions respectively oppose the picture elements of the picture element array of said liquid crystal, each of said regions of unit lenses having a rectangular shape, and the focal point of each unit lens is coincident substantially with a surface of said liquid crystal and with a center of a corresponding picture element electrode.
0. 2. A liquid crystal display element according to
0. 3. A liquid crystal display element according to
0. 4. A liquid crystal display using the liquid crystal display element according to
0. 5. A liquid crystal display according to
0. 6. A liquid crystal display according to
7. A transmission-type liquid crystal display according to
a liquid crystal display using said liquid crystal display element as a light valve, comprising at least said liquid crystal display element and an illumination optical system, wherein said illumination optical system has a concave mirror which acts to direct the luminous flux from a light source toward said liquid crystal display element and is arranged so that a shape of said concave mirror to a cross-section perpendicular to the optical axis of said illumination optical system is substantially similar to that of the aperture of said liquid crystal display element.
0. 8. A liquid crystal display according to
0. 9. A liquid crystal display according to
0. 10. A liquid crystal display according to
0. 11. A liquid crystal display according to
0. 12. A liquid crystal display using the liquid crystal display element according to
0. 13. A liquid crystal display according to
0. 14. A transmission-type liquid crystal display element for displaying picture information by an electrooptical effect of a liquid crystal injected between a pair of transparent substrates, wherein a light-incident side of one of said transparent substrates has integrally formed therein a flat plate micro-lens array which has regions of unit lenses arranged in the same manner as the picture elements of said liquid crystal so that said regions, respectively oppose the picture elements of the picture element array of said liquid crystal each of said regions of unit lenses having a rectangular shape, and the focal point of each unit lens is coincident substantially with a surface of said liquid crystal and with a center of a corresponding picture element electrode.
19. A liquid crystal display as claimed in
21. A liquid crystal display as claimed in
23. A liquid crystal display as claimed in
27. A liquid crystal display as claimed in
29. A liquid crystal display as claimed in
0. 32. A liquid crystal display according to
0. 33. A liquid crystal display according to
0. 34. A liquid crystal display according to
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This application is a 37 CFR §160 continuation of prior application Ser. No. 07/852,005, filed Mar. 16, 1992 (allowed) now U.S. Pat. No.
Embodiments of the invention will be described with reference to
Referring to
Shown at 16 is a flat-plate micro-lens array which is provided to be in intimate contact with the outer surface of the one transparent substrate 11. This lens-array is a refractive index distribution type micro-lens array which is produced by subjecting a transparent flat glass substrate to ion exchange. This lens-array is substantially a two-dimensional lens-array of a great number of unit lenses 16a arranged in rows and columns as indicated by broken lines in FIG. 1. Shown at 8, 8 are polarizing plates which are provided on the outer sides of the transparent substrates 11, 11. Although the polarizing plates 8 are separated from each other as illustrated, they may be made in intimate contact with each other. These liquid crystal cell, flat-plate micro-lens array, and polarizing plates constitute a liquid crystal display element 4. The flat-plate micro-lens array 16 is thus always provided on the light-incident side, 9 of the liquid crystal cell 5.
The positional relation and shapes of the main elements in this embodiment of the invention will be described with reference to FIG. 2. In
The flat-plate micro-lens array 16 shown in
According to the ion exchange process, a mask layer of a necessary pattern made of, for example, metal is formed on the transparent flat-plate glass substrate 26, and this substrate with the mask layer is immersed in a salt solution bath. At this time, positive ions such as Na+ (sodium ions) and K+ (calcium ions) contained in the glass are exchanged with the positive ions such as Tl+ (thallium ions) contained in the salt solution through the exposed surfaces of the glass. The ion-exchanged regions have a different refractive index from the original refractive index of the glass, and thus form refractive index distribution regions (unit lenses 16a) having a light refracting action. Since the micro-lenses formed by the ion exchange process have a lens action for refracting light within the transparent flat-plate glass substrate 26, the flat-plate micro-lens array 16 is flat in its surface. Also, by adjusting the shape of the mask layer of a necessary pattern and the time for the ion exchange (over-diffusion), it is possible to produce a two-dimensional matrix-shaped buried refractive index distribution-type lens array of which the unit lenses 16a of a flat shape such as a square or rectangle opposite to the respective picture elements of the liquid crystal cell have apparently no distance between the adjacent ones. This is the feature of this invention different from the conventional one. This effect will be mentioned below.
While in the flat-plate micro-lens array 16 of this embodiment the shape of the unit lens 16a completely coincides with that of the region 18 corresponding to one picture element of the liquid crystal display element, it may be the shape as for example shown in
The region 18 corresponding to one picture element of the liquid crystal cell is normally square or rectangular as illustrated. Thus, it is assumed that the region 18 has a rectangular shape with one side length of L1 and the other side length of L2 in which is shorter than L2. In addition, it is assumed that the region 18 includes the picture element electrode 14 as the aperture and the light-shielding portion 15. When the unit lens 16a of the flat-plate micro-lens array 16 is realized to be circular as in the prior art, the maximum diameter of each unit lens 16a is as shown in FIG. 6A. As a result, the light rays incident to the other area than the unit lens 16a (lens aperture), of the light incident to the region 18 corresponding to one picture element, cannot be effectively utilized. Thus, when the unit lens 16a is formed to be equal to the shape of the region 18 in order to effectively utilize all the light incident to the region 18 corresponding to one picture element, it is possible to form the flat-plate micro-lens array having the unit lens 16a of the shape shown in
(1) When the region 18 corresponding to one picture element of the liquid crystal cell is L1<L2,
(2) When the region 18 corresponding to one picture element of the liquid crystal cell is L1=L2,
then the flat-plate micro-lens array having the unit lenses 16a formed has a smaller improvement in the aperture ratio than the above embodiment, but can be formed (produced) in a shorter time than the above embodiment, thus having a high productivity such as cost reduction capability.
The above-mentioned action is concerned with the incident light ray 9 parallel to the optical axis of the lens. A description will be made of the flat-plate micro-lens array in which the incident light ray 9 is incident to the lens at an angle relative to the optical axis of the lens with reference to
In
On the other hand, when the light ray 9b is incident to the flat-plate micro-lens array 16 at an angle θ as in
where d is the distance from the back-side main point of the unit lens 16a to the liquid crystal surface 19, and n is the refractive index of the medium from the unit lens 16a to the liquid crystal surface 19. Thus, if conditions are set so that the diagonal length, D of the picture element electrode 14 (, or the aperture) within the region 18 corresponding to one picture element shown in
the light utilization efficiency dependent on the aperture ratio can be greatly improved over that in the prior art, or the apparent aperture ratio can be increased. Moreover, other means for improving the aperture ratio will also be given as shown in FIG. 8.
Referring to
In the embodiment of such construction, since the distance from the back-side main point of the unit lens 16a to the liquid crystal surface 19 can be greatly reduced, the aperture ratio is almost not dependent on the angle of incidence of light.
In
This embodiment shown in
In the embodiment shown in
A description will be made of an application of this invention to the twisted nematic mode (TN) as a peculiar example of the liquid crystal operation mode. The liquid crystal display element of the invention generally has a great view-angle dependency. The view angle for good characteristics in the TN mode liquid crystal device is different from the direction perpendicular to the display screen. Thus, as shown in
Point A in
where d is the distance from the back-side main point of the unit lens 16a to the liquid crystal surface 19, and n is the refractive index of the medium from the unit lens 16a to the liquid crystal surface 19. In other words, if the above equation is satisfied for a tilted condition of the liquid crystal display element, the light utilization efficiency dependent on the aperture ratio can be greatly improved as compared with the prior art.
A description will be made of an embodiment of the liquid crystal display which more effectively utilizes the liquid crystal display element of the invention as a light valve and which is another object of the invention.
In
In the projection type liquid crystal display shown in
In
The illumination optical system in
The illumination optical system in
In
Light is incident at various angles to the micro-lens array if the size of the light source as viewed from the micro-lens array cannot be neglected as compared with the distance between the light source and the micro-lens array. (the light source as viewed from the micro-lens array indicates the image of the light source as viewed through the illumination optical system when the light from the light source is passed through the illumination optical system such as a concave mirror to the micro-lens array, and the distance between the light source and the micro-lens array indicates the distance of the image of the light source.) In that case, when conditions such as the focal distance of the micro-lens array are set so that the image of the light source can be formed at around the liquid crystal surface of the liquid crystal display element, the aperture ratio is better, and a brighter display can be achieved. In that case, however, the shape of the light source directly reflects the shape of the luminous flux passed through the aperture of the liquid crystal display element. Thus, as shown in
The light source 1 used in the above embodiment is an halogen lamp as for example shown in FIG. 19A. The halogen lamp, 30 is formed of a quartz thin tube in which is enclosed, for example, argon gas mixed with a small amount of nitrogen gas and with a very small amount of halogen gas such as iodine, bromin, chlorine or fluorine. The filament, 31 shown in
The concave mirror, 36 shown in
As illustrated in
According to the embodiments shown in
In
The reflected blue light B is deflected by an all-reflecting mirror 41, and incident to the liquid crystal display element 4 (8, 16, 11, 13, 14, 15, 11, 8). On the other hand, the red light R and green light G passed through the B-reflecting dichroic mirror 40a are incident to a G-reflecting dichroic mirror 40b which is tilted at 45°C to the optical axis. The green light G is reflected from the G-reflecting dichroic mirror 40b, but the red light R is passed through the G-reflecting dichroic mirror. The reflected green light G is directly incident to another liquid crystal display element 4. The red light R passed through the G-reflecting dichroic mirror 40b is deflected by another all-reflecting mirror 41 and incident to the other liquid crystal display element 4.
The pictures R, G, B displayed on the liquid crystal 13 surfaces of the respective liquid crystal display elements 4 are added by a dichroic prism 42 which has a B-reflecting surface 43 and an R-reflecting surface 44 tilted at an angle of 45°C to the optical axis of the corresponding color light. The added picture is magnified and projected as a real image on the screen 7 by the projection lens 6.
The drive circuit for the liquid crystal display elements in this embodiment shown in
According to the embodiment of
Moreover, in the above embodiments of the invention, when a large-power light source is used for the liquid crystal display shown in
Thus, according to the invention, even if the aperture ratio is poor (or small) as one of the factors by which the light utilization efficiency is decreased as in the prior art, the liquid crystal display element is almost not affected by the poor aperture ratio, or has apparently a high aperture ratio, or can provide bright picture information, and the liquid crystal display using this liquid crystal display element is bright, easy to see and small-sized.
Yamasaki, Futoshi, Maruyama, Takesuke, Deguchi, Masaharu, Kakuda, Takashi, Ariki, Yoshio
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