JPH06265881A - Projection type display device - Google Patents

Abstract

PURPOSE:To transmit the light source light of the liquid crystal projection type display device which uses a CRT light source tube, to a screen with high efficiency. CONSTITUTION:Plural light emission parts 15 of the CRT type light source tube 10G equipped with a fluorescent body 19 which emits light by electronic beam excitation are provided corresponding to the area of a light valve 50G, and plural piano-convex lenses 30 are installed, one by one, closely on the front panel of the CRT light source tube 10G while having their centers closer to the optical axis of a projection lens than to the centers of the light emission parts. Thus, the projection lenses 30 are provided having their centers closer to the optical axis of the projection lens than to the centers of the light emission parts by the light emission parts 15, so light beams emitted by the light emission parts 15 are all converged by the convex lenses 30 and travel toward the projection lens after passing through the convex lenses.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device for irradiating an optical image formed on a light valve with irradiating light and projecting it onto a screen by a projection lens. The present invention relates to a condensing optical system.

[0002]

2. Description of the Related Art Conventionally, in order to display a large-screen image, an optical image corresponding to each color image signal is formed on a liquid crystal light valve for red, green, and blue, and a white light source such as a halogen lamp is used. It is well known that a more separated red, green, and blue light is applied to the optical image, combined again, and enlarged and projected on a screen by a projection lens. However, when a halogen lamp is used as a light source, power consumption is high and most of it is converted into heat, which causes a problem of heat dissipation and requires an optical system for separating white light into red, green, and blue. This has been an obstacle to the miniaturization and price reduction of the device.

Therefore, as a projection type display device which solves these problems, one disclosed in Japanese Patent Laid-Open No. 1-128689 has been proposed. FIG. 24 shows a configuration diagram of a conventional projection display device according to Japanese Patent Laid-Open No. 1-128689. In FIG. 24, 26R is a red light source tube that emits red light, 26G is a green light source tube that emits green light, and 26B is a blue light source tube that emits blue light. Each color light source tube can emit a single color CRT method. It is a light source tube. In addition, 67R is a liquid crystal light valve for red that modulates red light, 67G is a liquid crystal light valve for green that modulates green light, 67B is a liquid crystal light valve for blue that modulates blue light, and 62 is a modulated red light. , A synthetic prism for synthesizing green light and blue light, and 60 a projection lens for projecting synthetic light. Here, the size of the light emitting portion of each color light source tube is large enough to cover the image forming portions of the liquid crystal light valves 67R, 67G, and 67B for each color.

FIG. 25 is a sectional view of a CRT type light source tube which is a light source tube of each color. The CRT type light source tube shown in FIG. 25 has a structure similar to that of a cathode ray tube (CRT).
Cathode 101, first grid 102, second grid 103,
The third grid 104, the hyperfocus lens 105, and the glass bulb 10
Within 8 A fluorescent screen 107 is formed inside the front surface of the glass bulb. Further, an aluminum back 106 as a high voltage electrode for acceleration is provided on the inner surface of the fluorescent screen 107. The glass bulb 108 is attached to the base portion 109, and various electrodes are taken out through the base portion 109.

The operation will be described below.

First, in the CRT type light source tube shown in FIG. 25, the heater 100 is heated so that the first grid 102, the second grid 103,
An appropriate electric potential is applied to the third grid 104, a hyperfocus lens 105 is formed by each grid, and a high voltage of about 10 kV is applied to the aluminum back 106. This allows the cathode 101
The electron beam 110 from is focused after being accelerated and projected on the phosphor screen to emit visible light.

In this way, red light is emitted from the red light source tube 26R, and an image of the red component is displayed on the red liquid crystal light valve 67R. The image of red light transmitted through the red liquid crystal light valve 67R is reflected by the combining prism 62. Green light is emitted from the green light source tube 26G and an image of the green component is displayed on the green liquid crystal light valve 67G.
The image of the green light transmitted through the green liquid crystal light valve 67G is transmitted by the combining prism 62. Blue light is emitted from the blue light source tube 26B, and an image of the blue component is displayed on the blue liquid crystal light valve 67B. Liquid crystal light valve for blue
The image of the blue light transmitted through 67B is reflected by the combining prism 62. In this way, the image combined by the combining prism 62 is enlarged by the projection lens 60 and the projection light 72 is projected on the screen (not shown).

[0008]

The conventional projection display device is configured as described above, and since there is a space between the light valve and the light source, most of the light emitted from the light source, which is a perfect diffused light, is obtained. However, since the light is not incident on the light valve or the projection lens and is not guided to the screen, there is a problem that the utilization efficiency of the emitted light deteriorates.

The present invention has been made to solve the above problems, and an object thereof is to guide most of the emitted light to a light valve, a projection lens, and a screen. It is an object of the present invention to suppress uneven brightness of the screen, increase in size and weight of the device due to the achievement of.

[0010]

In order to achieve the above-mentioned object, a projection display device according to the present invention has a plurality of light emitting portions of a light source tube, and the light emitted from the light emitting portion is projected by each of the light emitting portions. A plano-convex lens that collects light toward the entrance aperture of the system,
It is installed between each light emitting part and the light valve.

Further, the light source tube has a plurality of electron beam generating means and a plurality of light emitting portions each including a phosphor layer which emits light when excited by an electron beam.

Further, each light emitting section is arranged on the same plane orthogonal to the optical axis of the projection optical system, the optical axis of each plano-convex lens is made parallel to the optical axis of the projection optical system, and the center of each light emitting section is arranged on it. The light emitting unit and the plano-convex lens are arranged so as to be farther from the optical axis of the projection optical system than that of the corresponding plano-convex lens.

Further, the respective light emitting portions are arranged in a matrix on the same plane orthogonal to the optical axis of the projection optical system, the optical axis of each plano-convex lens is made parallel to the optical axis of the projection optical system, and the light of each plano-convex lens is arranged. The plano-convex lenses are arranged at unequal pitches so that the axis is closer to the optical axis of the projection optical system than the center of the corresponding light emitting section.

Further, in the curved surface portion of the cross section including the optical axis of the projection optical system of each plano-convex lens, a part of the curved surface portion farther from the optical axis of the projection optical system than the optical axis of the plano-convex lens is cut, and In the curved surface portion of the plano-convex lens, the curved surface portion on the side closer to the optical axis of the projection optical system is extended to the optical axis side of the projection optical system.

Further, the light valve is arranged so that the distance from the light valve side end of the plano-convex lens to the light valve is shorter than 2/3 of the distance from the light emitting portion to the light valve side end of the plano-convex lens. It was installed.

Further, a transparent member is installed between the front panel of the light source tube and the curved surface portion of the plano-convex lens.

Further, between the front panel of the light source tube and the curved surface portion of the plano-convex lens, a transparent member having a plurality of conical shapes in which the cross-sectional area perpendicular to the optical axis increases from each light emitting portion toward the plano-convex lens. Is installed.

Furthermore, a reflecting layer is provided on the conical slope portion with the reflecting surface facing the inside of the conical shape.

[0019]

In the projection type display device according to the present invention, since the above-described plano-convex lens for condensing light is provided for each light emitting portion of the light source tube having a plurality of light emitting portions, most of the emitted light is It can be led to a light valve, projection lens, or screen.

Further, the light emitting efficiency is increased by causing each light emitting section to emit light by electron beam excitation.

Further, each light emitting portion is arranged in the same plane orthogonal to the optical axis of the projection optical system, and the center of each light emitting portion is farther from the optical axis of the projection optical system than the optical axis of the corresponding plano-convex lens. Since the light is emitted from each plano-convex lens, most of the light emitted from each plano-convex lens travels in the direction of the center of the projection lens, and the plano-convex lens array is realized by a structure suitable for integral molding.

Further, the respective light emitting parts are arranged in a matrix,
Since the optical axis of each plano-convex lens is located closer to the optical axis of the projection optical system than the center of the corresponding light-emitting section, the light-emitting sections of the light source tubes can be arranged regularly, By changing the position of the optical axis of each plano-convex lens of the plano-convex lens array, a configuration in which the distance between the plano-convex lens array and the focal point can be adjusted is realized.

Further, in the curved surface portion of the cross section including the optical axis of the projection optical system of each plano-convex lens, a part of the curved surface portion farther from the optical axis of the projection optical system than the optical axis of the plano-convex lens is cut, and Of the curved surface of the plano-convex lens, the curved surface on the side closer to the optical axis of the projection optical system is extended to the optical axis side of the projection optical system. And exits through the entrance aperture of the projection optical system.

Further, by disposing the light valve in the above position, the unevenness of the illuminance distribution on the light valve surface due to the light emitted from the converging plano-convex lens, passing through the projection lens, and reaching the screen is reduced.

Further, since the transparent member is provided between the front panel of the light source tube and the curved surface of the converging plano-convex lens, the thickness of the converging plano-convex lens array in the optical axis direction can be reduced. .

Further, a plurality of pyramidal shapes are formed between the front panel of the light source tube and the curved surface of the converging plano-convex lens so that the cross-sectional area perpendicular to the optical axis increases from each light emitting part toward the plano-convex lens. Since the transparent member is installed, the area of the portion of the front panel of the light source tube that is in contact with air becomes large.

Further, since the diffuse reflection layer is provided on the inclined surface of the conical transparent member, more light can be made incident on the projection optical system.

[0028]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3, 4, 5, and 6. FIG. 1 is a block diagram showing an embodiment of the projection display device of the present invention.
In the figure, 10R, 10G, and 10B are light source tubes for each color that emit red light 70R, green light 70G, and blue light 70B, respectively, and 30 is a condenser lens for a light source that collects light emitted from each color light source tube.
50R is a red liquid crystal light valve for modulating red light, 50G
Is a liquid crystal light valve for green that modulates green light, and 50B is a liquid crystal light valve for blue that modulates blue light. Also,
Reference numeral 62 is a composite prism that combines the modulated red light, green light, and blue light, and 60 is a projection lens that projects the combined light onto the screen 61.

FIG. 2 is an external perspective view of the green light source tube 10G and the light source condenser lens 30 shown in FIG. 1, and FIG. 3 shows the light source tube 10G having the light source condenser lens 30 shown in FIG. FIG. 4 is a plan view of the light source condensing lens 30 seen from the curved surface side. Furthermore, FIG.
Is a cross-sectional view taken along the line AA in FIG. 3 and the light valve.
It is a projection lens 60 with 50G. The synthetic prism is not shown in this figure. Source condenser lens 30 is a matrix planoconvex lens array formed by acrylic molding is composed of individual plano-convex lens 31 _{11-31 66,} the optical axis 73 are arranged at equal pitches. Here above 31 ₁₁ ~
31 ₆₆ 1st, the first second subscript first row to the sixth row, corresponding to the first column to the sixth column. The outer size of the lens portion of the matrix-shaped plano-convex lens array 30 is the same as the light valve 50.
It is sized to cover the G image display. The surface shape of the curved portion of each of the plano-convex lens 31 _{11-31 66} when setting the y-axis on a plane that is present in the light-emitting portion as shown in FIG. 5, (x
-C) ² / a ² + y ² / b ² = 1 (where, the distance between the optical axes 73 of the individual adjacent plano-convex lenses 31 _{11 to} 31 _{66 in} the diagonal direction of the matrix-shaped plano-convex lens array is L, When the refractive index of the convex lens is n, b ≧ L / 2, a = bn (n ² −
It is a spheroid formed by rotating an ellipse represented by 1) ^-1/2 and c = b (n ² -1) ^-1/2 ) around the x axis.

The light source tube 10G is composed of a vacuum container hermetically sealed by a front panel 11, a back plate 12 and a side plate 13, and a phosphor which emits green light when an electron beam 14 strikes the inner surface of the front panel 11. layer 19 (ZnS: Au, Cu, Al) emitting portion 15 _{11-15 66} (1st consisting second th subscript first row to the sixth row, corresponding to the first column to the sixth column. ) Exists. The light emitting portions are arranged in a matrix of 6 rows × 6 columns as shown in FIG. Here, the matrix lens array is constructed in such a thickness that the focal point O of the ellipse is located on the same plane as the light emitting portion of the front panel. The center line 72 of the light emitting unit is installed farther from the optical axis 80 of the projection optical system than the optical axis 73 of the corresponding plano-convex lens, and the center line 72 of the light emitting unit and the optical axis 73 of the corresponding plano-convex lens 31 are installed. Distance from
74 is made longer as it is farther from the optical axis 80 of the projection lens. The size of each light emitting portion 15 is set so that one side thereof is considerably smaller than the arrangement pitch of the light emitting portions. An electron gun 16 forms an overfocused electron beam 14, and an aluminum back layer 17 as an acceleration high-voltage electrode is attached to the electron beam irradiation surface side of the light emitting portion. Reference numeral 27 is a control grid electrode for adjusting the amount of the electron beam passing through the passage hole 28. Reference numeral 18 denotes a transparent adhesive, which adheres the matrix-shaped plano-convex lens array 30 and the front panel 11 without an air layer.

Next, the operation will be described. The overfocused electron beam 14 emitted from the electron gun 16 and passing through the passage hole 28 is
When each light emitting unit 15 is irradiated, green light is emitted from each light emitting unit. At this time, since the area of each light emitting section 15 is made small, the electron density incident on the phosphor layer 19 of each light emitting section becomes high, and each light emitting section 15 emits light with high brightness. When viewed microscopically, there is a space having a refractive index of 1 between the phosphor layer 19 of each light emitting portion 15 and the front panel 11. Therefore, the light emitted from each of the light emitting portions 15 that emits with high brightness is emitted to the front panel 11 and the entire half space of the phosphor layer space immediately after the emission of the phosphor layer 19, but immediately enters the front panel 11. All of these light fluxes travel within a cone whose half-vertical angle is φ {φ = sin ⁻¹ (1 / n): n is the refractive index of the front panel}. Since the front panel 11, the transparent adhesive 18, and the matrix-shaped plano-convex lens array 30 have almost the same refractive index, the total luminous flux that travels in the cone with the half-vertical angle φ goes straight as it is, and most of it travels in the matrix-shaped flat surface. The surface of each plano-convex lens 31 of the convex lens array 30 is reached. here,
As shown in (a) of FIG. 6, the light emitted from the light emitting point 15 on the optical axis 73 of the plano-convex lens 31 becomes a light beam parallel to the optical axis after exiting the plano-convex lens, but as shown in (b) of FIG. A light beam emitted from a point other than the axis 73 exits the plano-convex lens and then proceeds in a direction intersecting the optical axis 73 when viewed from the light emitting point 15. The larger the distance (eccentricity) 74 between the light emitting point 15 and the optical axis 73 of the plano-convex lens, the larger the angle between the traveling direction of the light flux after the projection of the plano-convex lens and the optical axis 73 of the plano-convex lens. Therefore, the traveling direction of the emitted light can be controlled by adjusting the eccentricity 74. In this embodiment, the eccentricity amount of the light emitting portion near the optical axis 80 of the projection lens is small, and the eccentricity amount of the light emitting portion distant from the optical axis 80 of the projection lens is 74
Since it is so large, a large amount of light travels in the opening direction of the projection lens 60.

The green light source tube 10G has been described above, but in the red light source tube 10R and the blue light source tube 10B as well, the phosphor layer of the light emitting portion is provided in the red light source tube 10R as Y ₂ O ₂ S: Eu ^3+.
In the blue light source tube 10B, ZnS: Ag, Cl is used, and the other components are the same as those of the green light source tube 10G. It is also possible to change the refractive index of the plano-convex lens 31 and the surface shape of the curved surface portion for each color.

The light emitted from each plano-convex lens 31 is composed of light valves 50R, 50G of the respective colors displaying images of the respective color components.
The light is transmitted through the entire image forming unit of 50B and is combined by the combining prism 62. Almost all of this combined light 71 enters the opening of the projection lens 60, is enlarged, and is projected on the screen 61.

In this embodiment, the control grid electrode 27 of the light source tube is composed of a common electrode so that the brightness of all the light emitting parts can be adjusted at the same time. However, an independent control grid electrode is provided for each light emitting part and The amount of light emitted from the matrix-shaped plano-convex lens array 30 is adjusted by changing the voltage applied to the control grid electrode of each of the light emitting units 15 ₁₁ to 15 ₆₆ and adjusting the amount of electrons (current value) irradiated to each light emitting unit. The spatial distribution of can also be controlled.

As the electron gun, either a hot cathode type or a cold cathode type may be used.

Furthermore, in the present embodiment, the light emitting portion of each color light source tube uses a phosphor that emits light when irradiated with a high-speed electron beam. However, a low-speed electron beam excited phosphor is used as the phosphor and serves as an anode. It is also possible to apply a voltage of several tens of V to the aluminum back layer 17 to emit light.

Further, in this embodiment, the inside of the light source tube is kept in vacuum, and the phosphor is irradiated with the electron beam generated from the electron gun so that the phosphor emits light.
It is also possible to enclose the mixed gas of e and apply a voltage to this gas to generate ultraviolet rays, and to excite the fluorescent materials with ultraviolet rays to cause the fluorescent materials for red, green and blue colors to emit light.

As described above, the matrix-shaped plano-convex lens array 30 including a plurality of plano-convex lenses 31 each having a convex ellipsoid is provided corresponding to the plurality of light-emitting parts 15 of the light source tube, and each light-emitting part 15 is provided. The center line 72 of the is located farther from the optical axis 80 of the projection lens 60 than the optical axis 73 of the corresponding plano-convex lens, and the distance 74 between the center line 72 of the light emitting section and the optical axis 73 of the corresponding plano-convex lens 74 Is longer as it is farther from the optical axis 80 of the projection lens, so that almost all the light emitted from the matrix-shaped plano-convex lens array 30 can enter the aperture of the projection lens 60, resulting in very high light utilization efficiency.

In this embodiment, the curved surface of the plano-convex lens has a spheroidal shape, but it may have a spherical surface.

Example 2. FIG. 7 is a sectional configuration diagram illustrating a second embodiment of the present invention. This sectional view is shown in FIG.
The cross section of the position corresponding to AA of FIG. Electron gun 16, electron beam 14, aluminum back 17, phosphor layer 19, light valve
The 50 G and the projection lens 60 are the same as those shown in the first embodiment. A straight line 81 _lm connecting the center of one light emitting portion 22 _{lm and} the center of the projection lens 60 and the light emitting portion 22 adjacent to the light emitting portion
_The angle 82 formed by the straight line 81 _{l'm '} connecting the _l'm' and the center of the projection lens 60 is the same for all the light emitting parts, and the distance 83 _lm between each light emitting part center and the projection lens is also equal. is doing. 20
Is a front panel of the light source tube, 21 is a rear panel, which is a spherical panel perpendicular to a straight line connecting the center of the light emitting unit and the center of the projection lens, and these and the side panel 13 form a vacuum inside. I keep it. 32 is a matrix plano convex lens array is composed of individual plano-convex lens 33 _{11-33 66,} each plane-convex lens is on the straight line 81 connecting the center of the entrance aperture of the center and the projection lens of the optical axis is the light emitting portion is there. The shape of the curved surface portion of each plano-convex lens 33 is the spheroidal shape described in the first embodiment, and is set so that the focus O coincides with the center of the light emitting portion. In this matrix-shaped plano-convex lens array 32, as shown in FIG. 8, individual plano-convex lenses 33 in which the vertices of pyramids are curved are made by processing acrylic, and their slopes are closely contacted and arranged in a matrix. Composed by.

In the second embodiment shown in FIG. 7, the light emitted from each light emitting portion 22 has the half-vertical angle φ {φ = sin ⁻¹ (1 / n): n by the same operation as in the first embodiment. Travels in the cone of the refractive index of the front panel} and reaches the curved surface portion of the plano-convex lens 33.
The light emitted from the plano-convex lens 33 becomes a light flux parallel to the optical axis 81 of the plano-convex lens and advances to the opening of the projection lens 60.

As described above, the center of the light emitting portion and the projection lens 60 are arranged on the optical axis of the plano-convex lens 33 that collects the light from each light emitting portion 22.
Since there is the center of the
Since all the light emitted from the curved surface portion enters the opening of the projection lens 60, the light source light can be used with high efficiency.

Example 3. FIG. 9 is a sectional configuration diagram illustrating a third embodiment of the present invention. FIG. 10 is a front view of FIG. 9 seen from the curved surface side of the condensing matrix-shaped plano-convex lens array 34. Emitting portion in FIG. 10 shows in broken lines, the light emitting portion 23 _{11-23 66} are then arranged in an equal pitch. Reference numeral 34 is a matrix-shaped plano-convex lens array molded by acrylic molding, and is composed of individual plano-convex lenses 35 _{11 to} 35 _66, and the curved surface of each plano-convex lens has the spheroidal shape described in the first embodiment. . The optical axis 84 of the plano-convex lens 35 is installed closer to the optical axis 80 of the projection lens 60 than the center line 85 of the corresponding light emitting section, and the optical axis 84 of the plano-convex lens 35 and the center line 85 of the corresponding light emitting section 85. The distance 86 to and is made longer as it is farther from the optical axis 80 of the projection lens. The size of each light emitting portion 23 is set so that one side thereof is considerably smaller than the arrangement pitch of the light emitting portions. Electron gun 16, electron beam 14, aluminum back 1
7, the phosphor layer 19, the light valve 50G, and the projection lens 60 are the same as those shown in the first embodiment. Reference numeral 18 denotes a transparent adhesive which bonds the matrix-shaped plano-convex lens 34 and the front panel 11 together without an air layer.

In the third embodiment shown in FIG. 9, the first embodiment is used.
Similarly to the above, in this embodiment, each light emitting unit 23 of the light source tube is
The light source tubes are easy to manufacture because they have the same pitch. Furthermore, since only the matrix-shaped plano-convex lens array 34 has an appropriate shape, the condensing action on the projection lens aperture can be changed, so that the same light source tube has various distances between the light source tube and the projection lens. It becomes easy to adapt to the projection optical system.

Although the light emitting portions of the light source tube are arranged at equal pitches in this embodiment, the light emitting portions are arranged at unequal pitches, and the optical axis of the plano-convex lens is arranged at a position close to the optical axis of the projection lens with respect to the center of light emission. You may.

Example 4. FIG. 11 is a sectional configuration diagram for explaining the fourth embodiment of the present invention. This sectional view is shown in FIG.
The cross section of the position corresponding to AA of FIG. Electron gun 16, electron beam 14, aluminum back 17, phosphor layer 19, light valve
The 50 G and the projection lens 60 are the same as those shown in the first embodiment. The light source tube 25 is identical to that shown in Example 3, the light emitting portion 23 _{11-23 66} are arranged in a matrix of equal pitch. Reference numeral 36 denotes a matrix-shaped plano-convex lens array, which is composed of individual plano-convex lenses 37 _{11 to} 37 ₆₆ , and each plano-convex lens is arranged on a straight line connecting the center of the light emitting portion to which the optical axis 87 corresponds and the center of the projection lens 60. is there. The shape of the curved surface portion of the plano-convex lens 37 is the spheroid described in the first embodiment,
It was installed so that the focus O coincided with the center of the light emitting part. However, the parameter b corresponding to the length of the minor axis of the ellipse is increased as the distance from the optical axis 80 of the projection lens is increased so that no gap is created between the adjacent lenses.

In the fourth embodiment shown in FIG. 11, the third embodiment is used.
The optical axis 87 of the spheroidal plano-convex lens 37 is directed toward the center of the projection lens 60 and the optical axis
Since the center of the light emitting portion 23 exists above 87, the light emitted from the plano-convex lens 37 has high parallelism, and the effect of condensing on the projection lens aperture can be increased.

Example 5. FIG. 12 is a plan view of part of a matrix-shaped plano-convex lens 38 for explaining the fifth embodiment of the present invention. FIG. 13 is a sectional view taken along the line AA 'in FIG. 12, showing the light valve 59G and the projection lens 60. The electron gun 16, the electron beam 14, the aluminum back 17, and the phosphor layer 19 are the same as those shown in the first embodiment. The light source tubes 24 are the same as those shown in the third embodiment, and the light emitting portions 23 are arranged in a matrix with an equal pitch. Matrix plano convex lens array 38 is composed of individual plano-convex lens 39 _{11-39 66,}
The surface shape of the curved surface portion of each plano-convex lens is spherical. The optical axis 88 of the plano-convex lens 39 is parallel to the optical axis 80 of the projection lens 60, and the emission center is on the optical axis 88. Further, as shown in FIG. 13, a part of the curved surface of the cross section of each plano-convex lens 39, which is farther from the optical axis 80 of the projection lens than the optical axis 88 of the plano-convex lens.
48 is cut diagonally from the light source tube 24 side to the light valve 50G side in the direction of the optical axis 80 of the projection lens, and the plano-convex lens 40 adjacent to the side farther from the optical axis 80 of the projection lens than the plano-convex lens 39 is. The curved surface portion 49 of is extended to the optical axis 80 side of the projection lens.

In the fifth embodiment, by the same operation as in the first embodiment, the light emitted from the light emitting section 23 is condensed by the plano-convex lens 39.
To the curved surface of. Here, as shown by the broken line in FIG. 14,
The boundary of the curved surface portion of each plano-convex lens 39 is an adjacent plano-convex lens.
In the configuration of the first embodiment, which is formed by the intersection line 89 with the curved surface portion of 40, the light 90 that reaches the adjacent lens curved surface portion on the side closer to the optical axis 80 of the projection lens (indicated by hatching in the figure). Travels at a large angle with respect to the optical axis 80 of the projection lens after the lens exits. For this reason, this light 91 does not enter the aperture of the projection lens and does not reach the screen, and thus becomes invalid light.
In the present embodiment, as shown by the solid line in FIG. 14, of the curved surface portions of each plano-convex lens, the area on the optical axis 80 side of the projection lens is increased, so that the light emitted from the light emitting portion is The amount of light condensed by the corresponding plano-convex lens 39 for condensing increases. The light 92 emitted from this plano-convex lens is
Since a part of the adjacent lenses 40 is cut obliquely, the amount of light that travels in the opening direction of the projection lens 80 without being refracted or reflected by the adjacent plano-convex lens 40 and reaches the screen is Since the number of light sources increases, the efficiency of using the light from the light source increases.

In this embodiment, the curved surface of the plano-convex lens is spherical, but it may be spheroid.

Example 6. FIG. 15 is a sectional view showing a sixth embodiment of the present invention. The matrix plano-convex lens array 38 is the same as that shown in the fifth embodiment,
Each plano-convex lens 39 _{11-39 66} are arranged in a matrix of equal pitch, and a portion of the curved surface portion of the plano-convex lens 39 is cut. Electron gun 16, electron beam 14, aluminum back 1
7, the phosphor layer 19, the light valve 50G, the projection lens 60 and the light source tube 10G are the same as those shown in the first embodiment, and the center line 72 of each light emitting portion 15 is the light of the corresponding plano-convex lens 39. It is installed farther from the optical axis 80 of the projection lens 60 than the axis 88, and the distance 93 between the center line 72 of the light emitting unit 15 and the corresponding optical axis 88 of the plano-convex lens is longer the farther from the optical axis 80 of the projection lens. Is provided.

In the sixth embodiment shown in FIG. 15, as in the fifth embodiment, the area of the curved surface of each plano-convex lens 39 on the optical axis 80 side of the projection lens is increased, and the adjacent plano-convex lens 40 is used. Since a part of the light is cut obliquely, a large amount of the light emitted from the light emitting unit 15 is condensed by the plano-convex lens 39 corresponding to the light emitting unit. Further, since the center line 72 of each light emitting unit is installed at a position farther from the optical axis 80 of the projection lens than the optical axis 88 of the corresponding plano-convex lens, the light emitted from each plano-convex lens 39 is directed in the optical axis direction of the projection lens. Progress more to. As described above, most of the light emitted from the light emitting portion is condensed by the condensing matrix plano-convex lens array 38 and travels to the opening of the projection lens 60, so that the light source light utilization efficiency is improved.

Example 7. FIG. 16 is a sectional configuration diagram for explaining the seventh embodiment of the present invention. Electron gun 16, electron beam 1
4, aluminum back 17, phosphor layer 19, light valve 50G,
Projection lens 60 and the light source tube 24 is of the same as shown in Example 5, the light emitting portion 23 _{11-23 66} are arranged in a matrix of equal pitch. 41 is a matrix plano convex lens array is composed of individual plano-convex lens 42 _{11-42 66,} the shape of the curved surface portion of the plano-convex lens 42 is a spheroid described in Example 1. Optical axis 93 of each plano-convex lens 42
Is the optical axis of the projection lens more than the center line 88 of the corresponding light emitting unit.
Installed at a position close to 80, the distance 94 between the optical axis 93 of the plano-convex lens and the corresponding center line of the light emitting unit is 80
The farther away from it, the longer. Furthermore, as in the case of the fifth embodiment,
Of the curved surface of the cross section of each plano-convex lens 42, a part of the part farther from the optical axis 80 of the projection lens than the optical axis 93 of the plano-convex lens,
From the light source tube 24 side to the light valve 50G side Optical axis of the projection lens
It is cut diagonally in the 80 direction, and a curved surface portion closer to the optical axis 80 of the projection lens than the optical axis 93 of the plano-convex lens is extended to the optical axis side 80 of the projection lens.

In the seventh embodiment shown in FIG. 16, as in the fifth embodiment, the area of the curved surface of each plano-convex lens 42 on the optical axis 80 side of the projection lens is increased, and the adjacent plano-convex lens 43 is arranged. Since a part of the curved surface part is obliquely cut, the amount of light condensed by the plano-convex lens 42 corresponding to the light emitting part increases among the light emitted from the light emitting part 23. Furthermore, since the optical axis 93 of each plano-convex lens is installed at a position closer to the optical axis 80 of the projection lens than the center line 88 of the corresponding light emitting portion, the light emitted from each plano-convex lens 42 is directed in the opening direction of the projection lens 60. Progress more to. As described above, most of the light emitted from the light emitting portion is condensed by the matrix-shaped plano-convex lens array 41 and travels to the opening of the projection lens, so that the utilization efficiency of the light source light can be increased and the light emission of the light source tube 24 can be increased. Since the parts have the same pitch, the light source tube can be easily manufactured.

Example 8. FIG. 17 is a sectional configuration diagram for explaining the eighth embodiment of the present invention. Electron gun 16, electron beam 1
4, the aluminum back 17, the phosphor layer 19, the light source tube 24, and the matrix-shaped plano-convex lens array 34 are the same as those shown in the third embodiment, and the light emitting portions 23 ₁₁ to 23 _{66 of the} light source tube 24 are the same. The optical axes 84 of the individual plano-convex lenses 35 of the matrix-shaped plano-convex lens array 34 are arranged at a pitch, and are arranged at a position closer to the optical axis 80 of the projection lens than the center line 85 of the corresponding light emitting unit 23,
Optical axis 84 of plano-convex lens and corresponding center line 85 of light emitting part
The distance 86 to and is made longer as it is farther from the optical axis 80 of the projection lens. 50G is a liquid crystal light valve, and 60 is a projection lens.
If the distance from the light emitting portion 23 to the light valve side tip of the matrix-shaped plano-convex lens array 34 is L, and the distance from the light valve side tip of the matrix-shaped plano-convex lens array 34 to the liquid crystal light valve 50G is D, then D <2L The liquid crystal light valve 50G is arranged to be / 3.

In the eighth embodiment shown in FIG. 17, the light from each light emitting portion 23 is condensed by the matrix-shaped plano-convex lens array 34 by the same operation as in the third embodiment, and the image forming portion of the liquid crystal light valve 50G is formed. Irradiate. The image projected on the screen (not shown) is formed by the light transmitted through the image forming unit, which is incident on the opening of the projection lens and transmitted to the screen. Fig. 18 shows a computer simulation that consists of an optical system consisting of 6 light emitting parts as shown in Fig. 17 and 6 plano-convex lenses whose optical axes are offset from the center of each light emitting part in the optical axis direction of the projection lens. Then, the illuminance distribution on the liquid crystal light valve surface by the light emitted from each light emitting portion and incident on the projection lens is obtained. The size of the light emitting unit 23 is a line segment with a length of 4 mm, the distance from the optical axis 80 of the projection lens to the center line of the light emitting unit farthest from the projection lens is 36 mm, and the light of the projection lens of each plano-convex lens The distance from the axis 80 to the optical axis of the plano-convex lens farthest away is 31.5 mm, and the deviation amount of the optical axis of each light emitting part and the optical axis of the corresponding plano-convex lens is d ₁ = 1.5 from the side closer to the optical axis of the projection lens. mm, d ₂ =
It was set to 3.5 mm and d ₃ = 4.5 mm. Further, the distance L from the light emitting portion to the tip of the matrix-shaped plano-convex lens array on the light valve side was set to 15 mm.

18 (a), (b) and (c) show the liquid crystal when the distance D from the light valve side tip of the matrix-shaped plano-convex lens array to the liquid crystal light valve 50G is 1 mm, 10 mm and 20 mm, respectively. It is the illuminance distribution on the light valve surface. Figure
As shown in 18, the smaller D is, the smoother the shape of the illuminance distribution is. This is because the light emitted from each plano-convex lens travels toward the opening direction of the projection lens, and thus the light emitted from the adjacent plano-convex lens overlaps as D increases.

In the eighth embodiment shown in FIG. 17, the distance D from the light valve side tip of the matrix-shaped plano-convex lens array 34 installed in the light source tube 24 to the liquid crystal light valve 50G, and the distance from the light emitting portion to the matrix-shaped plano-convex lens array are set. Since the liquid crystal light valve 50G is arranged so that the distance L to the tip on the light valve side is 2/3 or less, the light is emitted from the light emitting part 23,
The illuminance distribution on the liquid crystal light valve surface due to the light incident on the projection lens 60 is smoothed, and the illuminance distribution of the image projected on the screen is also smoothed.

In the present embodiment, the light emitting portions of the light source tube are arranged at an equal pitch, and the plano-convex lenses of the matrix-shaped plano-convex lens array are arranged at unequal pitches.
Each plano-convex lens may have an equal pitch. Further, a part of each plano-convex lens 35 can be obliquely cut as in the fifth, sixth and seventh embodiments.

Example 9. FIG. 19 is an exploded perspective view for explaining the ninth embodiment of the present invention, and FIG. 20 is a sectional configuration diagram.
Electron gun 16, electron beam 14, aluminum back 17, phosphor layer 19
The light source tube 10G is the same as that shown in the first embodiment. Reference numeral 44 denotes a matrix-shaped plano-convex lens array, the shape of the curved surface of the lens is the same as that shown in the first embodiment, but the length k ₁ in the optical axis direction is made shorter than that shown in the first embodiment. There is. Reference numeral 63 is a flat plate formed of transparent acrylic, and is closely attached between the front panel 11 of the light source tube and the matrix-shaped plano-convex lens array 44. Thickness of plate 63 k
₂ indicates that the distance K from the light emitting portion 15 of the light source tube 10G to the tip of the lens curved surface portion of the matrix-shaped plano-convex lens array 44 corresponds to the distance K between the light emitting portion 15 and the lens curved surface portion of the matrix-shaped plano-convex lens array 30 shown in the first embodiment. It is set to be the same as the distance to the tip.

In this embodiment, the front panel 11 of the light source tube 10G is used.
Since the light emitted from the front panel 11, the transparent flat plate 63, and the matrix-shaped plano-convex lens array 44 have almost the same refractive index, they are not reflected or refracted at each interface and enter the curved surface of the matrix-shaped plano-convex lens array 44. Reach Further, the light emitted from the lens can be incident on the projection lens (not shown) with high efficiency by the same operation as that of the first embodiment. Further, since the matrix-shaped plano-convex lens array 44 can be made thin, thermal strain during injection molding of acrylic is reduced, and the matrix-shaped plano-convex lens array 44 can be easily manufactured with high accuracy. Further, since the thickness of the front panel of the light source tube can be reduced, the weight of the light source tube can be reduced.

In this embodiment, the light emitting portions of the light source tube are arranged at an unequal pitch, and the plano-convex lenses of the matrix-shaped plano-convex lens array are arranged at an equal pitch. You may use the pitch. Further, as in the fifth, sixth and seventh embodiments, the matrix-shaped plano-convex lens array is used.
It is also possible to cut a part of each plano-convex lens forming 44 at an angle.

Example 10. FIG. 21 is a sectional configuration diagram illustrating a tenth embodiment of the present invention. Electron gun 16, electron beam 1
4, the aluminum back 17, the phosphor layer 19, the light source tube 10G, and the matrix-shaped plano-convex lens array 44 are the same as those shown in the ninth embodiment, but the optical axis of each plano-convex lens is set to the light emission of the light source tube. It matches the department. 64 is a molded product made of transparent acrylic, the light valve 50G side is a flat surface, and the light source tube
The 10G side is configured by arranging a plurality of pyramids 65, which have a cross-sectional area perpendicular to the optical axis increasing toward the light valve side, in a matrix. FIG. 22 is a part of a plan view of the transparent acrylic material 64 seen from the light source tube 10G side. The center line 95 of each pyramid 65 is arranged so as to be located on the optical axis 96 of each plano-convex lens 45 of the matrix-shaped plano-convex lens array 44.
The vicinity of the apex of each pyramid 65 is a plane, and the area of this plane is large enough to cover the light emitting section 15 of the light source tube so that all the light from the light emitting section can enter. The thickness h ₂ of the transparent acrylic material 64 in the optical axis direction is equal to the light emitting portion of the light source tube.
The distance H from 15 to the surface of the matrix-shaped plano-convex lens array 44 on the light valve side is set to be the same as the distance from the light emitting portion 15 shown in the first embodiment to the surface of the matrix-shaped plano-convex lens array 30 on the light valve side. is doing.

In the tenth embodiment, the light emitted from the light emitting portion 15 of the light source tube 10G passes through the front panel 11 and then the pyramid portion 65 of the transparent acrylic material 64 and travels to the lens curved surface portion of the matrix-shaped plano-convex lens array 44. To do. In this embodiment, as in the ninth embodiment, since the thickness h ₁ of the matrix-shaped plano-convex lens array 44 is small, the acrylic injection molding can be easily performed with high precision. The light source tube side of the transparent member 65 installed between the light source tube 10G and the matrix-shaped plano-convex lens array 44 is formed by arranging the pyramids 65 whose flats are near the vertices in a matrix. Since there is a space between the front panel 11 of the tube 10G and the transparent acrylic material 64, a portion of the front panel 11 of the light source tube that comes into contact with air is generated, and the cooling effect between the light sources 10G is increased. Although not shown,
It goes without saying that the effect is enhanced by blowing air or passing a cooling liquid into this space. Further, the weight of the transparent acrylic material 64 can be reduced.

In the present embodiment, the optical axis 96 of each plano-convex lens 45 of the matrix-shaped plano-convex lens array 44 is aligned with the center of the light emitting portion of the light source tube, but the optical axis 96 of the plano-convex lens 45 emits light from the light source tube. The plano-convex lens 45 and the light emitting section 15 may be arranged so as to be closer to the optical axis of the projection lens than the center of the section.

Example 11. FIG. 23 is a sectional view showing the eleventh embodiment of the present invention. Electron gun 16, electron beam 1
4, the aluminum back 17, the phosphor layer 19, the light source tube 10G, the transparent acrylic material 64, and the matrix-shaped plano-convex lens array 44 are the same as those shown in the tenth embodiment. Reference numeral 66 denotes a diffuse reflection layer closely attached to the slope of the transparent member, and the reflection layer faces the slope of the transparent member.

In this embodiment, the light emitted from the light emitting portion 15 of the light source tube 10G passes through the front panel 11 as in the case of the tenth embodiment.
Proceed to the pyramid portion 65 of the transparent acrylic material 64. Here, the light incident on the slope of the pyramid portion 65 made of a transparent acrylic material is a diffuse reflection layer.
Since the light is diffusely reflected by 66, it is not emitted to the outside of the transparent acrylic material but is repeatedly reflected inside the transparent acrylic material 64, and a part of the light proceeds to the matrix-shaped plano-convex lens array 44. The light that has traveled to the matrix-shaped plano-convex lens array 44 is condensed and travels in the opening direction of the projection lens. In this way, by placing the transparent acrylic material 64 composed of a plurality of pyramids having the diffuse reflection layer 66 on the slope portion between the light source tube 10G and the matrix-shaped plano-convex lens array 44, the light emitting section of the light source tube emits light. Of the above-mentioned light, more light is condensed by the matrix-shaped plano-convex lens array 44 and guided to the projection lens, and the light source tube 10G has a cooling effect.

[0068]

Since the present invention is constructed as described above, it has the following effects.

A plurality of light emitting parts of the light source tube are provided, and a plano-convex lens for converging the light emitted from the light emitting parts toward the opening of the projection optical system is provided between each light emitting part and the light valve. By doing so, most of the emitted light is a light valve,
It can be guided to the projection lens and screen, and a bright image can be obtained on the screen.

Further, since light emission efficiency is increased by causing each light emitting section to emit light by electron beam excitation, it is possible to provide a projection display device capable of displaying an image with high brightness and low power consumption.

A plurality of light emitting parts are located in a plane orthogonal to the optical axis of the projection optical system, the optical axis of each plano-convex lens is parallel to the optical axis of the projection optical system, and the center of the light emitting part corresponds to it. The light emitting part and the plano-convex lens are arranged so that they are farther from the optical axis of the projection optical system than the optical axis of the plano-convex lens. It is possible to make a projection display device that is inexpensive and rich in price.

Further, the light condensing rate can be easily changed only by fixing the array pitch of the light emitting portions of the light source tube and changing the position of the optical axis of the plano-convex lens for condensing. The light source tube can be easily adapted to various projection optical systems in which the distance between the light source tube and the projection lens is different.

Further, of the curved surface portion of the cross section including the optical axis of the projection optical system of the converging plano-convex lens, a part of the plano-convex lens adjacent to the optical axis side of the projection optical system is obliquely cut to form the projection optical system. By extending the part close to the optical axis of the projection optical system in the direction of the optical axis of the projection optical system, much of the light emitted from the light emitting part is condensed by the plano-convex lens corresponding to that light emitting part. Become. In addition, the amount of light that travels in the opening direction of the projection lens and reaches the screen without being refracted or reflected by the adjacent plano-convex lens increases, so that the utilization efficiency of the light from the light source increases.

Further, the light is arranged so that the distance from the light valve side tip of the converging plano-convex lens to the light valve is shorter than 2/3 of the distance from the light emitting portion to the light valve side tip of the plano-convex lens. By installing the bulb, the unevenness of the illuminance distribution on the light valve surface is reduced by the light emitted from the plano-convex lens, passing through the projection lens, and reaching the screen, so that an image with uniform brightness can be obtained on the screen.

Further, since the transparent flat plate is arranged between the front panel of the light source tube and the curved surface portion of the matrix-shaped plano-convex lens array for condensing, the thickness of the matrix-shaped plano-convex lens array in the optical axis direction is set. Since it can be made thin, the matrix-shaped plano-convex lens array can be easily manufactured.

Further, between the front panel of the light source tube and the curved surface portion of the matrix-shaped plano-convex lens array, a plurality of pyramids whose cross-sectional area perpendicular to the optical axis increases from each light emitting portion toward the plano-convex lens are arranged in a matrix. By installing the transparent members arranged and arranged, the cooling effect of the light source tubes is increased and the weight of the condensing optical system can be reduced.

Furthermore, by disposing a diffuse reflection layer on the slope portion of the pyramid with the reflecting surface facing the inside of the pyramid,
Since most of the light source light can be made incident on the matrix-shaped plano-convex lens array for condensing and the projection optical system, the utilization efficiency of the light source light is increased and a bright projected image can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a light source tube and a matrix-shaped plano-convex lens array according to the first embodiment of the present invention.

FIG. 3 is a front view of a matrix-shaped plano-convex lens array according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of a light source tube and a matrix-shaped plano-convex lens array according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a lens surface shape according to the first embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the first embodiment of the present invention.

FIG. 7 is a sectional view of a light source tube and a matrix-shaped plano-convex lens array according to a second embodiment of the present invention.

FIG. 8 is a perspective view of a plano-convex lens forming the matrix-shaped plano-convex lens array according to the second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a light source tube and a matrix-shaped plano-convex lens array according to a third embodiment of the present invention.

FIG. 10 is a front view of a matrix-shaped plano-convex lens array according to a third embodiment of the present invention.

FIG. 11 is a sectional view of a light source tube and a matrix-shaped plano-convex lens array according to a fourth embodiment of the present invention.

FIG. 12 is a front view showing a part of a matrix-shaped plano-convex lens array according to Example 5 of the present invention.

FIG. 13 is a sectional view of a light source tube and a matrix-shaped plano-convex lens array according to a fifth embodiment of the present invention.

FIG. 14 is a diagram for explaining the operation of the fifth embodiment of the present invention.

FIG. 15 is a sectional view of a light source tube and a matrix-shaped plano-convex lens array according to a sixth embodiment of the present invention.

FIG. 16 is a sectional view of a light source tube and a matrix-shaped plano-convex lens array according to a seventh embodiment of the present invention.

FIG. 17 is a sectional view of a light source tube, a matrix-shaped plano-convex lens array, and a liquid crystal panel showing Embodiment 8 of the present invention.

FIG. 18 is a diagram of an illuminance distribution on a liquid crystal panel surface by simulation for explaining the operation of Example 8 of the present invention.

FIG. 19 is a perspective view of a light source tube, a transparent member, and a matrix-shaped plano-convex lens array showing Embodiment 9 of the present invention.

FIG. 20 is a sectional view of a light source tube, a transparent member, and a matrix-shaped plano-convex lens array showing Example 9 of the present invention.

FIG. 21 is a sectional view of a light source tube, a transparent member, and a matrix-shaped plano-convex lens array according to a tenth embodiment of the present invention.

FIG. 22 is a front view of a transparent member of Example 10 of the present invention.

FIG. 23 is a sectional view of a light source tube, a transparent member, and a matrix-shaped plano-convex lens array according to an eleventh embodiment of the present invention.

FIG. 24 is a configuration diagram showing an example of a conventional invention.

FIG. 25 is a cross-sectional view of a light source tube according to an embodiment of the conventional invention.

[Explanation of symbols]

16 Electron gun 19 Phosphor 10G Light source tube 50G Liquid crystal light valve 60 Projection lens 80 Projection optical system Optical axis 30 Equal-pitch matrix plano-convex lens array 32 Optical axis and plane inclined matrix plano-convex lens array 34 Unequal pitch matrix -Shaped plano-convex lens array 36 Optical axis tilt type matrix-shaped plano-convex lens array 38 Cut-type matrix-shaped plano-convex lens array 41 Cut-type unequal-pitch matrix-shaped plano-convex lens array 63 Transparent flat plate 64 Pyramidal configuration type transparent member 66 Diffuse reflection layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mutsuhiro Shima 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Material Device Research Center (72) Inventor Hiroshi Ouchida 8-1-1 Tsukaguchihonmachi, Amagasaki No. Mitsubishi Electric Corp. Material Devices Research Laboratory (72) Inventor Tomio Kawato 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Corp. Material Devices Research Laboratory

Claims (9)

[Claims] 1. A light source tube having a plurality of light emitting portions made of a phosphor layer, a light valve on which an optical image is formed according to a video signal, and an optical image of the light valve by light emitted from the light source tube. In a projection display device having a projection optical system for projecting on a screen, a plano-convex lens for condensing light emitted from each of the light emitting units toward an entrance opening of the projection optical system is provided for each of the plurality of light emitting units. A projection type display device characterized in that it is installed between each of the light emitting parts and the light valve so as to correspond to each part. 2. The projection display device according to claim 1, wherein the light source tube has a plurality of electron beam generating means and a plurality of light emitting portions each including a phosphor layer that emits light when excited by an electron beam. 3. The plurality of light emitting units are located in a plane orthogonal to the optical axis of the projection optical system, the optical axis of each plano-convex lens is parallel to the optical axis of the projection optical system, and 3. The projection type according to claim 1, wherein the light emitting unit and the plano-convex lens are arranged such that a center thereof is farther from an optical axis of the projection optical system than a corresponding optical axis of the plano-convex lens. Display device. 4. The plurality of light emitting units are arranged in a matrix in a plane orthogonal to the optical axis of the projection optical system, and the optical axis of each plano-convex lens is located above the center of the corresponding light emitting unit. 4. The projection display device according to claim 3, wherein the plano-convex lenses are arranged at unequal pitches so as to be close to the optical axis of the system. 5. A light source tube having a plurality of light emitting portions made of a phosphor layer, a light valve on which an optical image is formed according to a video signal, and each light emitting portion corresponding to each light emitting portion of the plurality of light emitting portions. A plurality of plano-convex lenses for converging the light emitted from each of the light emitting parts between the light source and the light valve, and a projection optical system for projecting an optical image of the light valve by the light emitted from the light source tube onto a screen. In the projection display device, a part of the curved portion of the cross section including the optical axis of the projection optical system of the plano-convex lens, which is farther from the optical axis of the projection optical system than the optical axis of the plano-convex lens, is cut. At the same time, the projection display device is characterized in that a curved surface portion of the curved surface portion closer to the optical axis of the projection optical system than the optical axis of the plano-convex lens is extended to the optical axis side of the projection optical system. 6. A light source tube having a plurality of light emitting portions each comprising a phosphor layer, a light valve for forming an optical image according to a video signal, and each light emitting portion corresponding to each light emitting portion of the plurality of light emitting portions. A plurality of plano-convex lenses for converging the light emitted from each of the light emitting parts between the light source and the light valve, and a projection optical system for projecting an optical image of the light valve by the light emitted from the light source tube onto a screen. In the projection display device, the light valve is located at a position where the distance from the light valve side tip of the plano-convex lens is shorter than 2/3 of the distance from the light emitting section to the light valve side tip of the plano-convex lens. The projection display device according to claim 1, wherein the projection display device is installed. 7. A light source tube comprising a front panel having a plurality of light emitting portions each comprising a phosphor layer, an envelope and a rear panel,
A light valve on which an optical image corresponding to a video signal is formed,
A projection optical system for projecting an optical image of a light valve on the screen by the light emitted from the light source tube, and the light emitting units corresponding to the light emitting units of the plurality of light emitting units, and In a projection display device including a plurality of plano-convex lenses that collect light emitted from a light-emitting unit, a transparent member is provided between a front panel of the light source tube and a curved surface section of the plano-convex lens. The projection display device according to claim 1. 8. A plurality of pyramidal shapes are formed between the front panel of the light source tube and the curved surface portion of the plano-convex lens so that the cross-sectional area perpendicular to the optical axis increases from each light emitting portion toward the plano-convex lens. 8. A transparent member is provided, and the transparent member is installed.
The projection display device described. 9. The projection display device according to claim 8, wherein a diffused reflection layer is provided on the conical slope portion so that a reflection surface faces the inside of the conical shape.