JP2000307905A - View finder and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a view finder for allowing a user to use a large screen and a video with high resolution. SOLUTION: A view finder is indicated so as to be loaded on a video camera. A view finder 103 is provide with a display element 103-1 and an optical element 103-2. A video displayed on the display element 103-1 is enlarged by the optical element 103-2, and projected to eye balls 105 of a user so as to be recognized. Therefore, the user can confirm a large video by observing the view finder without observing any outside liquid crystal panel. Thus, this video finder can be made convenient for the observation of a subject.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates to a viewfinder.
In particular, it relates to a viewfinder used for a video camera or the like.

[0003]

[Prior art]

In recent years, digital cameras and video cameras equipped with a CCD image sensor have become widespread as CCD image sensors have become higher resolution and smaller. Here, FIG.
FIG. 1 shows an external view of a conventional video camera.

[0005] 2001 is a video camera body, 2002 is a liquid crystal panel, 2003 is a viewfinder, 2004 and 2005 are operation switches, and 2006 is a lens. The video camera shown in FIG.
Is converted into a video signal by a CCD image sensor, and the video signal is recorded on a recording medium. The liquid crystal panel 2002 and the viewfinder 2003 are display devices that display the video signal.

As shown in FIG. 8B, a user 2100 can photograph a subject while observing an image projected on a viewfinder 2003. Here, a conventional viewfinder 2003 is shown in FIG. Note that 210
0-1 indicates an eyeball on either the left or right of the user 2100. The viewfinder 2003 has a small liquid crystal panel 2003-1, and a user can observe an image displayed on the small liquid crystal panel 2003-1.

In the conventional viewfinder, the image of the viewfinder 2003 observed by the user 2100 is an image of the small liquid crystal panel 2003-1. The image is small, the resolution is low, and it is very difficult to recognize the image. is there. Therefore, it was practically difficult for the user 2100 to photograph the subject while checking the image on the viewfinder 2003.

Therefore, a conventional video camera is equipped with an external liquid crystal panel as shown by 2002 in FIG. Conventionally, the size of the external liquid crystal panel 2002 is about 2 inches to 4 inches,
003 is relatively large for the image identified by
The resolution is also high. The user 2100 can shoot a subject or reproduce a recorded image while checking the image projected on the external liquid crystal panel 2002.

[0009]

[Problems to be solved by the invention]

However, this external liquid crystal panel 2
002 has a larger screen size than the small liquid crystal panel 2003-1 of the viewfinder 2003, and therefore consumes more power. When the video camera is used while the external liquid crystal panel 2002 is operated, the power consumption is about 1.5 times as much as that when the external liquid crystal panel 2002 is not operated. Therefore, using the video camera while operating the external liquid crystal panel 2002 has a great effect on the battery life, which is one of the biggest problems for a video camera that emphasizes outdoor use and portability. . Therefore, the use of the video camera while checking the display on the external liquid crystal panel 2002 is not only beneficial for the user.

FIG. 10 is an external view of a conventional digital camera. Reference numeral 3001 denotes a digital camera body;
Reference numeral 3002 denotes a liquid crystal panel, 3003 denotes a shutter button, and 3004 and 3005 denote operation switches. The user can shoot while checking the image projected on the liquid crystal panel 3002, and can reproduce and check the recorded image.

However, as the size and resolution of the liquid crystal panel increase, the power consumption of the liquid crystal panel increases, which poses a problem for digital cameras that are intended for outdoor use as well as video cameras.

[0013]

[Means for Solving the Problems]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and realizes a viewfinder which can reduce a low power consumption and provide a large screen and high resolution video to a user. It is.

According to the present invention, it is possible to enlarge an image on a small display element (typically, a liquid crystal panel) provided in the viewfinder. Then, the user can observe the enlarged image by looking through the viewfinder. For example, the user can observe a 60-inch image projected 2 m ahead. Therefore, according to the present invention, the user of the video camera can confirm a large image by observing the viewfinder without observing the external liquid crystal panel.

Referring to FIG. FIG. 1 shows a viewfinder according to the present invention mounted on a video camera. As shown in FIG. 1, the viewfinder 103 of the present invention includes a display element 103-1 and an optical element 103-.
Two. The image displayed on the display element 103-1 is enlarged by the optical element 103-2 and projected on the user's eyeball 105 and recognized. Therefore, the user can confirm a large image by observing the viewfinder without observing the external liquid crystal panel, which is convenient for observing the subject.

The viewfinder of the present invention can be used for various semiconductor devices using a viewfinder other than a video camera.

Here, the configuration of the viewfinder of the present invention will be described below.

The viewfinder of the present invention has a display element and an optical element for enlarging an image displayed on the display element.

A viewfinder according to the present invention has a display element and a plurality of optical elements for enlarging an image displayed on the display element.

Further, the viewfinder of the present invention has a display element and an optical element for enlarging an image displayed on the display element and projecting the image on the user's eyeball.

A viewfinder according to the present invention includes a display element, and a plurality of optical elements for enlarging an image displayed on the display element and projecting the image on a user's eyeball.

The display element used in the viewfinder of the present invention may be a liquid crystal display element.

The display element used in the viewfinder of the present invention may be an organic EL display element.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the viewfinder of the present invention will be described below. However, the viewfinder of the present invention is not limited to the following embodiments.

(Embodiment 1)

Referring to FIG. FIG. 2 shows a state in which the viewfinder 203 of the present embodiment is mounted on the video camera 201. Viewfinder 2 of the present invention
03 has a display element 203-1 and optical elements 203-2 and 203-3 as shown in FIG.
The light emitted from the display element 203-1 is reflected by the optical element 20.
The light passes through 3-3 and enters the optical element 203-2. The light incident on the optical element 203-2 is reflected on the reflection surface of the optical element 203, exits from the transmission surface, and exits from the viewfinder 203. Video camera 201
The user recognizes the enlarged image by observing the light emitted from the viewfinder 203 of the present invention.

In the optical element 203-3 used in the viewfinder 203 of this embodiment, the incident light is reflected twice on the reflection surface and exits from the transmission surface. As described above, according to the view finder 203 of the present embodiment, the image displayed on the display element 203-1 is
2 and 203-3, the user's eyeball 2
05 is recognized. Therefore, the user can confirm a large image by observing the viewfinder 203 without observing the external display device.

A liquid crystal panel is typically used as a display element of the viewfinder of the present embodiment. The display mode of the liquid crystal panel may be a twisted nematic (TN) mode using a nematic liquid crystal or an electric field control birefringence mode. Further, a liquid crystal panel may be formed using a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or a mixed liquid crystal thereof. A ferroelectric liquid crystal or an antiferroelectric liquid crystal that responds to an applied voltage without a threshold value, or a mixed liquid crystal thereof can also be used.

FIG. 11 is a graph showing the characteristics of light transmittance with respect to the applied voltage of the thresholdless antiferroelectric mixed liquid crystal.
Shown in The polarization axis of the polarizing plate on the incident side of the liquid crystal panel is set substantially parallel to the normal direction of the smectic layer of the thresholdless antiferroelectric mixed liquid crystal, which substantially matches the rubbing direction of the liquid crystal panel. The polarization axis of the exit-side polarizing plate is set to be substantially perpendicular (crossed Nicols) to the polarization axis of the entrance-side polarizing plate. As described above, it can be understood that when the thresholdless antiferroelectric mixed liquid crystal is used, it is possible to perform a gradation display showing the applied voltage-transmittance characteristic as shown in FIG.

In general, a thresholdless antiferroelectric mixed liquid crystal has a large spontaneous polarization and a high dielectric constant of the liquid crystal itself. Therefore, when a thresholdless antiferroelectric mixed liquid crystal is used for a liquid crystal display device, a relatively large storage capacitance is required for a pixel. Therefore, it is preferable to use a thresholdless antiferroelectric mixed liquid crystal having a small spontaneous polarization. In addition, when the driving method of the liquid crystal panel is line-sequential driving, the writing period (pixel feed period) of the gradation voltage to the pixel can be lengthened, and even if the storage capacity is small, it can be compensated.

Since low-voltage driving is realized by using a thresholdless antiferroelectric liquid crystal, low power consumption of the liquid crystal display device is realized.

FIG. 3 shows an example of a video camera using the viewfinder 203 of this embodiment. FIG.
1A, 1B, and 1C, reference numeral 201 denotes a video camera body; 203, a viewfinder according to the embodiment; 204, a lens; and 206 and 207, operation switches. FIG. 3B illustrates a video camera equipped with an external liquid crystal panel 208. Note that the video camera in FIG. 3A and the video camera in FIG. 3B have different shapes and sizes of the video camera body.

As in the video camera shown in FIG.
Even in video cameras equipped with an external LCD panel,
The viewfinder of the present embodiment can also be used.
In this case, the enlarged image can be observed by observing the viewfinder 203 without operating the external liquid crystal panel 208. Therefore, the viewfinder of the present embodiment is convenient when the video camera must be driven by a battery outdoors or the like.

(Embodiment 2)

Referring to FIG. FIG. 4 shows the viewfinder according to the present embodiment mounted on a video camera 401. Viewfinder 403 of the present invention
Has a display element 403-1 and an optical element 403-2, as shown in FIG. The optical element 403-2 is
An optical element such as a lens. The light emitted from the display element 403-1 enters the optical element 403-3, is enlarged, and is emitted from the viewfinder 403. The user of the video camera 401 recognizes the enlarged image by observing the light emitted from the viewfinder 403 of the present invention.

As described above, according to the viewfinder 403 of this embodiment, the image displayed on the display element 403-1 is enlarged by the optical element 403-2 and recognized by the user's eyeball 405. Therefore, the user can confirm a large image by observing the viewfinder 403 without observing the external display device.

As the display element 403-1 of this embodiment, the one described in the first embodiment can be used. Also,
As an example of the video camera using the viewfinder according to the present embodiment, the video camera shown in FIG.

(Embodiment 3)

Referring to FIG. FIG. 5 shows a state in which the viewfinder of the present embodiment is mounted on a video camera 501. Viewfinder 503 of the present invention
Has a display element 503-1 and an optical element 503-2 as shown in FIG. Light emitted from the display element 503-1 enters the optical element 503-2. The light incident on the optical element 503-2 is reflected on the reflection surface of the optical element 503-2, is emitted from the transmission surface, and is emitted from the viewfinder 503. Video camera 5
01 observes the light emitted from the viewfinder 503 of the present invention to recognize the enlarged image.

As described above, according to the viewfinder 503 of this embodiment, the image displayed on the display element 503-1 is enlarged by the optical element 503-2 and recognized by the user's eyeball 505. Therefore, the user can confirm a large image by observing the viewfinder 503 without observing the external display device.

As the display element 503-1 of this embodiment, the one described in the first embodiment can be used. Also,
As an example of the video camera using the viewfinder according to the present embodiment, the video camera shown in FIG.

(Embodiment 4)

In this embodiment, the above-described first to fifth embodiments are described.
The case where the viewfinder of the present invention described in 3 is used in a digital camera will be described.

Referring to FIG. FIG. 6 shows a digital camera equipped with the viewfinder of the present invention described in the first to third embodiments. 601 is a digital camera main body, 602 is a viewfinder of the present invention, 603 is a shutter button, and 604 and 605 are operation switches.

Since the digital camera 601 of this embodiment is equipped with the viewfinder 602 of the present invention, a user observing the viewfinder 602 can check the enlarged screen. Therefore, it is very convenient when shooting with a digital camera and when playing back images.

(Embodiment 5)

Referring to FIG. FIG. 7A shows a state in which the viewfinder according to the present embodiment is mounted on a video camera 701. Viewfinder 7 of the present invention
03 has a display element 703-1. Display element 7
FIG. 7B shows an enlarged view of 03-1. The display element 703-1 of this embodiment includes a substrate 703-1-1, a substrate 703-1-2, and a display medium 703-1-3. In the present embodiment, the display medium 703
-1-3 liquid crystal is used. One substrate 703-1-2 of the display element 703-1 has a spherical surface on the light emission side, and functions as a lens. Display element 703-
The light emitted from 1 is emitted from the viewfinder 703. The user of the video camera 701
By observing the light emitted from the viewfinder 703 of the present invention, an enlarged image is recognized.

As described above, according to the viewfinder 703 of this embodiment, the image displayed on the display element 703-1 is enlarged and recognized by the user's eyeball 705. Therefore, the user can confirm a large image by observing the viewfinder 703 without observing the external display device.

As the display element 703-1 of the present embodiment, the one described in the first embodiment can be used. Also,
As an example of a video camera or a digital camera using the viewfinder of the present embodiment, the one shown in FIG. 3 described in the first or fourth embodiment can be used.

(Embodiment 6) In this embodiment, an example in which an EL (electroluminescence) display device is manufactured as a display device of a viewfinder according to the present invention will be described.

FIG. 12A is a top view of the EL display device of this embodiment. 12A, reference numeral 4010 denotes a substrate, 4011 denotes a pixel portion, 4012 denotes a source side driver circuit,
Reference numeral 4013 denotes a gate-side drive circuit. Each drive circuit reaches an FPC 4017 via wirings 4014 to 4016 and is connected to an external device.

FIG. 12B shows a cross-sectional structure of the EL display device of this embodiment. At this time, the cover member 6 is formed so as to surround at least the pixel portion, preferably the drive circuit and the pixel portion.
000, sealing material 7000, sealing material (second sealing material)
7001 is provided.

Further, a TFT for a driving circuit (here, an n-channel type TF) is formed on the substrate 4010 and the base film 4021.
1 illustrates a CMOS circuit combining a T and a p-channel TFT. ) 4022 and TFT 4023 for pixel portion
(However, here, only the TFT for controlling the current to the EL element is shown).

TFT 4022 for driving circuit, TF for pixel portion
When T4023 is completed, a pixel electrode 4027 made of a transparent conductive film electrically connected to the drain of the pixel portion TFT 4023 is formed on an interlayer insulating film (flattening film) 4026 made of a resin material. As the transparent conductive film, a compound of indium oxide and tin oxide (called ITO) or a compound of indium oxide and zinc oxide can be used. After the pixel electrode 4027 is formed, an insulating film 4028 is formed, and an opening is formed over the pixel electrode 4027.

Next, an EL layer 4029 is formed. The EL layer 4029 is formed of a known EL material (a hole injection layer, a hole transport layer,
A light-emitting layer, an electron transport layer, or an electron injection layer) may be freely combined to form a stacked structure or a single-layer structure. A known technique may be used to determine the structure. Also, E
The L material includes a low molecular material and a high molecular (polymer) material. When a low molecular material is used, an evaporation method is used, but when a high molecular material is used, a spin coating method,
A simple method such as a printing method or an inkjet method can be used.

In this embodiment, an EL layer is formed by an evaporation method using a shadow mask. By forming a light-emitting layer (a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer) capable of emitting light having different wavelengths for each pixel using a shadow mask, color display becomes possible. In addition, the color conversion layer (CC
M) and a color filter are combined, and a white light-emitting layer and a color filter are combined. Either method may be used. Needless to say, a monochromatic EL display device can be used.

After forming the EL layer 4029, a cathode 4030 is formed thereon. Cathode 4030 and EL layer 4029
It is desirable to remove as much as possible moisture and oxygen existing at the interface. Therefore, the EL layer 4029 and the cathode 40 in vacuum
It is necessary to devise a method of continuously forming the film 30 or forming the EL layer 4029 in an inert atmosphere and forming the cathode 4030 without opening to the atmosphere. In this embodiment, the above-described film formation can be performed by using a multi-chamber method (cluster tool method) film forming apparatus.

In this embodiment, as the cathode 4030, a laminated structure of a LiF (lithium fluoride) film and an Al (aluminum) film is used. Specifically, the EL layer 4029
A LiF (lithium fluoride) film having a thickness of 1 nm is formed thereon by a vapor deposition method, and an aluminum film having a thickness of 300 nm is formed thereon. Of course, a MgAg electrode which is a known cathode material may be used. The cathode 4030 is connected to the wiring 4016 in a region indicated by 4031. The wiring 4016 is a power supply line for applying a predetermined voltage to the cathode 4030, and the FPC 40 through a conductive paste material 4032.
17 is connected.

The cathode 40 in the region indicated by 4031
In order to electrically connect the wiring 30 and the wiring 3016, it is necessary to form contact holes in the interlayer insulating film 4026 and the insulating film 4028. These are at the time of etching the interlayer insulating film 4026 (at the time of forming the contact hole for the pixel electrode).
Or when the insulating film 4028 is etched (when an opening is formed before the EL layer is formed). Also, the insulating film 40
When etching 28, etching may be performed all at once up to the interlayer insulating film 4026. In this case, the interlayer insulating film 40
If the same resin material is used for the insulating film 26 and the insulating film 4028, the shape of the contact hole can be made good.

The passivation film 6003 and the filler 600 cover the surface of the EL element thus formed.
4. The cover material 6000 is formed.

Further, a sealing material 700 is provided inside the cover material 6000 and the substrate 4010 so as to surround the EL element portion.
0 is provided, and a sealing material (second sealing material) 7001 is formed outside the sealing material 7000.

At this time, the filler 6004 also functions as an adhesive for bonding the cover material 6000.
As the filler 6004, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 6004 because a moisture absorbing effect can be maintained.

Further, a spacer may be contained in the filler 6004. At this time, the spacer may be a granular substance made of BaO or the like, and the spacer itself may have hygroscopicity.

When a spacer is provided, the passivation film 6003 can reduce the spacer pressure.
Further, a resin film or the like for relaxing the spacer pressure may be provided separately from the passivation film.

As the cover material 6000, a glass plate, an aluminum plate, a stainless steel plate, FRP (Fiber)
rglass-Reinforced Plastic
s) plate, PVF (polyvinyl fluoride) film,
Mylar film, polyester film or acrylic film can be used. The filling material 600
When PVB or EVA is used as 4, it is preferable to use a sheet having a structure in which aluminum foil of several tens of μm is sandwiched between PVF films or Mylar films.

However, depending on the direction of light emission (the direction of light emission) from the EL element, the cover material 6000 needs to have translucency.

The wiring 4016 passes through the gap between the sealing material 7000 and the sealing material 7001 and the substrate 4010, and
It is electrically connected to the PC 4017. Although the wiring 4016 has been described here, the other wirings 4014,
Similarly, the sealing material 7000 and the sealing material 70
01 and electrically connected to the FPC 4017.

(Embodiment 7) In this embodiment, an example in which an EL display device different from that of Embodiment 6 is manufactured will be described with reference to FIGS. FIG.
Elements having the same numbers as 3 (A) and 13 (B) indicate the same parts, and thus description thereof will be omitted.

FIG. 13A is a top view of the EL display device of this embodiment, and FIG. 13B is a cross-sectional view taken along line AA ′ of FIG.

According to the sixth embodiment, up to the passivation film 6003 is formed to cover the surface of the EL element.

Further, the filler 6 is formed so as to cover the EL element.
004 is provided. This filler 6004 is used for the cover material 60.
It also functions as an adhesive for bonding 00. As the filler 6004, PVC (polyvinyl chloride),
Epoxy resin, silicone resin, PVB (polyvinyl butyral) or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 6004 because a moisture absorbing effect can be maintained.

Further, a spacer may be contained in the filler 6004. At this time, the spacer may be a granular substance made of BaO or the like, and the spacer itself may have hygroscopicity.

When a spacer is provided, the passivation film 6003 can reduce the spacer pressure.
Further, a resin film or the like for relaxing the spacer pressure may be provided separately from the passivation film.

As the cover material 6000, a glass plate, an aluminum plate, a stainless steel plate, FRP (Five)
rglass-Reinforced Plastic
s) plate, PVF (polyvinyl fluoride) film,
Mylar film, polyester film or acrylic film can be used. The filling material 600
When PVB or EVA is used as 4, it is preferable to use a sheet having a structure in which aluminum foil of several tens of μm is sandwiched between PVF films or Mylar films.

However, depending on the direction of light emission (the direction of light emission) from the EL element, the cover material 6000 needs to have translucency.

Next, the cover material 6
After bonding 000, the side surface of filler 6004 (exposed surface)
Frame material 6001 is attached so as to cover. The frame material 6001 is a sealing material (functioning as an adhesive) 60.
No. 02. At this time, the sealing material 6002
It is preferable to use a photocurable resin as the
A thermosetting resin may be used if the heat resistance of the layer permits. Note that the sealant 6002 is preferably a material that does not transmit moisture or oxygen as much as possible. In addition, the sealing material 600
A desiccant may be added to the inside of 2.

The wiring 4016 is electrically connected to the FPC 4017 through a gap between the sealing material 6002 and the substrate 4010. Note that although the wiring 4016 has been described here, the other wirings 4014 and 4015 are also electrically connected to the FPC 4017 under the sealant 6002 in the same manner.

(Embodiment 8) In this embodiment, a more detailed sectional structure of a pixel portion in an EL display panel is shown in FIG.
15A shows a top view structure, and FIG. 15B shows a circuit diagram.
Shown in In FIGS. 14, 15A and 15B, a common reference numeral is used, so that they may be referred to each other.

In FIG. 14, the switching TFT 3002 provided on the substrate 3001 is the TFT of the sixth embodiment.
A structure may be used, or a known TFT structure may be used. Although the present embodiment has a double gate structure,
The description is omitted because there is no significant difference in the structure and the manufacturing process. However, the double gate structure has a structure in which two TFTs are substantially connected in series, and has an advantage that an off-current value can be reduced. In this embodiment, a double gate structure is used, but a single gate structure, a triple gate structure, or a multi-gate structure having more gates may be used.

The current controlling TFT 3003 is made of NTF
It is formed using T. At this time, the switching TF
The drain wiring 3035 of T3002 is electrically connected to the gate electrode 3037 of the current controlling TFT by a wiring 3036. The wiring denoted by 3038 is a gate electrode 3039a of the switching TFT 3002,
The gate wiring 3039b is electrically connected.

Since the current control TFT is an element for controlling the amount of current flowing through the EL element, a large amount of current flows, and the element has a high risk of deterioration due to heat or hot carriers. Therefore, a structure in which an LDD region is provided on the drain side of the current control TFT so as to overlap with the gate electrode via the gate insulating film is extremely effective.

In the present embodiment, the current controlling TFT 3
Although 003 is shown in a single-gate structure, a multi-gate structure in which a plurality of TFTs are connected in series may be used. Further, a structure in which a plurality of TFTs are connected in parallel to substantially divide the channel formation region into a plurality of regions so that heat can be radiated with high efficiency may be employed. Such a structure is effective as a measure against deterioration due to heat.

Further, as shown in FIG. 15A, the wiring which becomes the gate electrode 3037 of the current controlling TFT 3003 is a region indicated by 3004 in the current controlling TFT 3003.
Overlap with the drain wiring 3040 via the insulating film. At this time, a capacitor is formed in a region indicated by 3004. This capacitor 3004 is used for the current control TFT 30.
It functions as a capacitor for holding the voltage applied to the gate of the gate 03. Note that the drain wiring 3040 is connected to a current supply line (power supply line) 3006, and a constant voltage is constantly applied.

The first passivation film 3 is formed on the switching TFT 3002 and the current control TFT 3003.
041 is provided, and a planarizing film 3042 made of a resin insulating film is formed thereon. TF using the flattening film 3042
It is very important to flatten the step due to T. Since an EL layer formed later is extremely thin, poor light emission may be caused by the presence of a step. Therefore, E
It is desirable to planarize the pixel layer before forming the pixel electrode so that the L layer can be formed as flat as possible.

Reference numeral 3043 denotes a pixel electrode (cathode of an EL element) made of a highly reflective conductive film, and a current control TF
It is electrically connected to the drain of T3003. As the pixel electrode 3043, a low-resistance conductive film such as an aluminum alloy film, a copper alloy film, or a silver alloy film, or a stacked film thereof is preferably used. Of course, a stacked structure with another conductive film may be employed.

A light emitting layer 3045 is formed in a groove (corresponding to a pixel) formed by banks 3044a and 3044b formed of an insulating film (preferably resin). Although only one pixel is shown here, R
Light emitting layers corresponding to the colors (red), G (green), and B (blue) may be separately formed. As the organic EL material for the light emitting layer, a π-conjugated polymer material is used. A typical polymer-based material is polyparaphenylene vinylene (PPV)
System, polyvinyl carbazole (PVK) system, polyfluorene system and the like.

There are various types of PPV-based organic EL materials, for example, “H. Shenk, H. Becker, O. Ge.
lsen, E. Kluge, W. Kreuder, and H. Spreitzer, “Polymers
forLight Emitting Diodes ”, Euro Display, Proceeding
s, 1999, p.33-37 "and JP-A-10-92576.

As specific light-emitting layers, cyanopolyphenylenevinylene is used for a light-emitting layer emitting red light, polyphenylenevinylene is used for a light-emitting layer emitting green light, and polyphenylenevinylene or polyalkylphenylene is used for a light-emitting layer emitting blue light. Good. The film thickness is 30-150n
m (preferably 40 to 100 nm).

However, the above example is an example of the organic EL material that can be used for the light emitting layer, and it is not necessary to limit the invention to this. An EL layer (a layer for performing light emission and carrier movement therefor) may be formed by freely combining a light emitting layer, a charge transport layer, or a charge injection layer.

For example, in this embodiment, an example in which a polymer material is used as the light emitting layer has been described, but a low molecular organic EL material may be used. It is also possible to use an inorganic material such as silicon carbide for the charge transport layer and the charge injection layer. Known materials can be used for these organic EL materials and inorganic materials.

In this embodiment, PE is formed on the light emitting layer 3045.
EL having a laminated structure provided with a hole injection layer 3046 made of DOT (polythiophene) or PAni (polyaniline)
And layers. An anode 3047 made of a transparent conductive film is provided over the hole injection layer 3046. In the case of the present embodiment, since the light generated in the light emitting layer 3045 is emitted toward the upper surface (toward the upper side of the TFT), the anode must be translucent. As the transparent conductive film, a compound of indium oxide and tin oxide or a compound of indium oxide and zinc oxide can be used; however, it is possible to form after forming a light-emitting layer or a hole-injecting layer with low heat resistance. A material that can form a film at a temperature as low as possible is preferable.

When the anode 3047 is formed, the EL element 3005 is completed. The EL element 30 referred to here
05 denotes a pixel electrode (cathode) 3043, a light emitting layer 3045,
It refers to a capacitor formed by the hole injection layer 3046 and the anode 3047. As shown in FIG.
Since 43 substantially corresponds to the area of the pixel, the entire pixel is EL
Functions as an element. Therefore, the efficiency of light emission is extremely high, and a bright image can be displayed.

In the present embodiment, the anode 3047
Further, a second passivation film 3048 is provided thereon. As the second passivation film 3048, a silicon nitride film or a silicon nitride oxide film is preferable. The purpose of this is to shut off the EL element from the outside, and has both the meaning of preventing the organic EL material from being deteriorated due to oxidation and the effect of suppressing outgassing from the organic EL material. Thereby, the reliability of the EL display device is improved.

As described above, the EL display panel of this embodiment has a pixel portion composed of pixels having a structure as shown in FIG. 14, a switching TFT having a sufficiently low off-current value, and a current control resistant to hot carrier injection. TFT. Therefore, an EL display panel having high reliability and capable of displaying a good image can be obtained.

(Embodiment 9) In this embodiment, a structure in which the EL element 3005 in the pixel portion shown in Embodiment 8 is inverted will be described. FIG. 16 is used for the description. Note that the point different from the structure of FIG. 15 is only the EL element portion and the current controlling TFT, and the other description will be omitted.

In FIG. 16, the current control TFT 310
3 is formed using PTFT.

In this embodiment, the pixel electrode (anode) 305
As 0, a transparent conductive film is used. Specifically, a conductive film formed using a compound of indium oxide and zinc oxide is used. Of course,
A conductive film formed using a compound of indium oxide and tin oxide may be used.

Then, a bank 3051a made of an insulating film,
After the formation of 3051b, a light emitting layer 3052 made of polyvinyl carbazole is formed by solution coating. An electron injection layer 3053 made of potassium acetylacetonate and a cathode 3054 made of an aluminum alloy are formed thereon. In this case, the cathode 3054 also functions as a passivation film. Thus, an EL element 3101 is formed.

In the case of this embodiment, the light generated in the light emitting layer 3052 is radiated toward the substrate on which the TFT is formed as shown by the arrow.

The configuration of this embodiment is the same as that of Embodiments 1 to
7 can be implemented in any combination.

(Embodiment 10) In this embodiment, FIG.
FIGS. 17A to 17C illustrate an example in which a pixel having a structure different from that of the circuit diagram illustrated in FIG. In this embodiment, 3201 is the switching TFT 32.
02, a source wiring 3203, a switching TFT 3
The gate wiring 202, 3204 is a current controlling TFT, 3
205 is a capacitor, 3206 and 3208 are current supply lines, and 3207 is an EL element.

FIG. 17A shows an example in which a current supply line 3206 is shared between two pixels. That is, the feature is that two pixels are formed to be line-symmetric with respect to the current supply line 3206. In this case, the number of power supply lines can be reduced, so that the pixel portion can have higher definition.

FIG. 17B shows the current supply line 320.
8 is provided in parallel with the gate wiring 3203. Note that in FIG. 17B, the current supply line 3208 and the gate wiring 3203 are provided so as not to overlap with each other.
They can be provided so as to overlap with each other via an insulating film. In this case, since the power supply line 3208 and the gate wiring 3203 can share an occupied area, the pixel portion can have higher definition.

FIG. 17C shows that the current supply line 3208 is provided in parallel with the gate wiring 3203 and the two pixels are connected to the current supply line 3208 similarly to the structure of FIG.
It is characterized in that it is formed so as to be line-symmetric with respect to.
It is also effective to provide the current supply line 3208 so as to overlap with one of the gate wirings 3203. In this case, the number of power supply lines can be reduced, so that the pixel portion can have higher definition.

(Embodiment 11) In FIGS. 15A and 15B shown in Embodiment 18, a current controlling TFT 3003 is shown.
Capacitor 30 to hold the voltage across the gate of
04 is provided, but the capacitor 3004 can be omitted. In the case of Embodiment 11, a TFT having an LDD region provided so as to overlap a gate electrode with a gate insulating film interposed therebetween is used as the current controlling TFT 3003. A parasitic capacitance generally called a gate capacitance is formed in this overlapping region.
The present embodiment is characterized in that this parasitic capacitance is positively used instead of the capacitor 3004.

Since the capacitance of the parasitic capacitance changes depending on the area where the gate electrode and the LDD region overlap, it is determined by the length of the LDD region included in the overlapping region.

FIG. 17 shown in the tenth embodiment.
Similarly, in the structures (A), (B), and (C), the capacitor 3205 can be omitted.

[0110]

【The invention's effect】

According to the present invention, a large screen and high resolution video can be provided by the viewfinder.
Therefore, according to the present invention, a user of a video camera or a digital camera can confirm a large image by observing the viewfinder without observing an external large-screen liquid crystal panel.

Therefore, according to the present invention, low power consumption of a digital camera or a video camera can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a video camera having a viewfinder according to the present invention.

FIG. 2 is a schematic configuration diagram of a video camera having a viewfinder according to the present invention.

FIG. 3 is a perspective view of a video camera having a viewfinder according to the present invention.

FIG. 4 is a schematic configuration diagram of a video camera having a viewfinder according to the present invention.

FIG. 5 is a schematic configuration diagram of a video camera having a viewfinder according to the present invention.

FIG. 6 is a schematic configuration diagram of a digital camera having a viewfinder according to the present invention.

FIG. 7 is a schematic configuration diagram of a video camera having a viewfinder according to the present invention.

FIG. 8 is a perspective view of a conventional video camera and a scene in use thereof.

FIG. 9 is a schematic configuration diagram of a video camera having a conventional viewfinder.

FIG. 10 is an external view of a conventional digital camera.

FIG. 11 is a graph showing an applied voltage-transmittance characteristic of a thresholdless antiferroelectric mixed liquid crystal.

FIG. 12 is a diagram illustrating a configuration of an EL display device according to a sixth embodiment.

FIG. 13 is a diagram illustrating a configuration of an EL display device according to a seventh embodiment.

FIG. 14 is a cross-sectional view illustrating a configuration of a pixel portion of an EL display device according to an eighth embodiment.

FIGS. 15A and 15B are a top view and a circuit diagram illustrating a configuration of a pixel portion of an EL display device in Embodiment 8. FIGS.

FIG. 16 is a cross-sectional view illustrating a configuration of a pixel portion of an EL display device according to a ninth embodiment.

FIG. 17 is a circuit diagram illustrating a configuration of a pixel portion of an EL display device according to a tenth embodiment.

[Explanation of symbols]

 Reference Signs List 101 Video camera body 103 Viewfinder 103-1 Display element 103-2 Optical element 104 Lens 105 User's eyeball

Claims (7)

[Claims] A display element; an optical element for enlarging an image displayed on the display element;
Viewfinder with 2. A viewfinder, comprising: a display element; and a plurality of optical elements for enlarging an image displayed on the display element. 3. A viewfinder comprising: a display element; and an optical element for enlarging an image displayed on the display element and projecting the image on a user's eyeball. 4. A viewfinder comprising: a display element; and a plurality of optical elements for enlarging an image displayed on the display element and projecting the enlarged image onto a user's eyeball. 5. The viewfinder according to claim 1, wherein said display element is a liquid crystal display element. 6. The viewfinder according to claim 1, wherein said display element is an organic EL display element. 7. A semiconductor device having the view finder according to claim 1.