JP4815939B2 - Display device - Google Patents

Description

  The present invention relates to a reflective or transflective liquid crystal display device having an illumination unit on a reflective liquid crystal display unit.

  A liquid crystal display device (hereinafter referred to as an LCD) has a feature of being thin and has low power consumption, and is currently widely used as a monitor for a computer or a portable information device such as a mobile phone. LCDs include transmissive LCDs, reflective LCDs, and transflective LCDs.

  A transmissive LCD uses a transparent electrode as a pixel electrode for applying a voltage to a liquid crystal, and a backlight is placed behind the LCD. By controlling the amount of light transmitted through the backlight, a bright display can be obtained even when the surroundings are dark. it can. However, there is a characteristic that a sufficient contrast cannot be secured in an environment with strong external light such as outdoors in the daytime.

A reflective LCD uses external light such as sunlight or room light as a light source, and reflects the external light incident on the LCD by a reflective pixel electrode formed of a reflective layer formed on a substrate on the observation surface side.
Then, display is performed by controlling the amount of light emitted from the LCD panel of light incident on the liquid crystal and reflected by the reflective pixel electrode for each pixel. Since this reflective LCD uses external light as a light source, there is a problem that display cannot be performed in an environment without external light.

  The transflective LCD has both a transmissive function and a reflective function, and can cope with a bright environment or a dark environment. However, this transflective LCD has a problem that the display efficiency per pixel is poor because it has a transmissive region and a reflective region in one pixel.

In view of this, it has been considered to enable display even in a dark environment by providing a front light on the reflective LCD. FIG. 18 is a diagram showing a reflective LCD provided with a front light. A transparent acrylic plate 110 is disposed facing the display surface of the reflective LCD 100. A plurality of inverted triangular grooves 111 are formed on the surface of the transparent acrylic plate 110 opposite to the surface facing the reflective LCD. A light source 112 is disposed on the side surface of the transparent acrylic plate 110. The light introduced from the light source 112 into the transparent acrylic plate 110 is refracted in the direction of the reflective LCD 100 by the inclined surface of the groove 111 and is incident on the display surface of the reflective LCD 100.
JP-A-5-325586 JP 2003-255375 A

  However, the light introduced from the light source 112 into the transparent acrylic plate 110 is refracted in the direction of the reflective LCD 100 on the inclined surface of the groove 111 provided in the transparent acrylic plate 110 and is observed in the opposite direction. Since the light 113 is refracted somewhat in the direction in which the person 113 is present, the light leaks from the transparent acrylic 110 and enters the eyes of the observer, which causes a problem of reducing the contrast of the LCD.

  The display device of the present invention has been made in view of the above problems, and modulates and reflects light incident from the observation side based on the optical characteristics of the display layer by controlling the voltage applied to the display element. An emission display unit (reflection liquid crystal display unit 300) and an illumination unit (illumination unit 200) that is partially provided on the observation side of the display unit and emits light toward the display unit. A display device that irradiates the display unit with one or both of incident external light and light from the illumination unit, and radiates reflected light from the display unit to the observation side, wherein the illumination unit includes the display A first substrate (first transparent substrate 10) whose back surface is disposed in a part, a second substrate bonded to the first substrate via a seal layer (second transparent substrate 20), Arranged between the first substrate and the second substrate at a predetermined inter-row pitch and / or inter-column pitch. A light-emitting unit composed of an electroluminescent element, wherein the display unit has a plurality of pixels arranged in a second direction, and a reflective pixel electrode that receives light generated from the light-emitting unit is provided for each pixel. A third substrate formed on the substrate, a fourth substrate disposed on the third substrate and having a common electrode formed on a surface thereof, and between the third substrate and the fourth substrate. And the pitch between the rows and / or the pitch of the light emitting portions made of the electroluminescence elements are formed in a plurality of types in the display region.

  The display device of the present invention employs, as a front light, a bottom emission type organic electroluminescence element (a type in which light emitted from the organic electroluminescence element is emitted to the substrate side on which the organic electroluminescence element is formed). Thus, a bright and high-contrast liquid crystal display can be realized in both a bright environment and a dark environment.

Next, a display device according to a first embodiment of the present invention will be described with reference to the drawings.
1 and 2 are diagrams showing the overall configuration of a reflective liquid crystal display device. In the figure, an illumination unit 200 (front light type illumination device) is joined on a reflective liquid crystal display unit 300 (reflection type liquid crystal display device). The configuration of the illumination unit 200 is as follows. The first transparent substrate 10 made of a glass substrate or the like and the second transparent substrate 20 are bonded to each other via a seal layer 11 made of a resin or the like applied to each peripheral end portion.

  The back surface of the first transparent substrate 10 is bonded to the reflective liquid crystal display unit 300, and an organic electroluminescence element 12 (hereinafter referred to as “organic EL element 12”) is formed on the surface of the first transparent substrate 10. Yes. As a result, the organic EL element 12 is enclosed in a space surrounded by the first transparent substrate 10, the second transparent substrate 20, and the seal layer 11. The organic EL element 12 is formed in a region corresponding to the pixel region 310 (see FIG. 3) of the reflective liquid crystal display unit 300.

  The organic EL element 12 includes an anode layer 13 formed on the first transparent substrate 10, an organic layer 14 formed so as to cover the anode layer 13, and an island shape (island shape) on the organic layer 32. A plurality of cathode layers 15 formed with a pattern, and a transparent electrode layer 18 formed so as to cover the cathode layers 15 and electrically connected to the cathode layers 15. The cathode layer 15 formed in an island shape is formed so that the shape of the light emitting portion plane is the shortest perimeter per area. That is, the shape of the island-shaped light emitting portion plane is preferably a circle as shown in FIG. 2C, but may be a square as shown in FIG. 2A or a rectangle as shown in FIG. 2B. In addition, an ellipse, a rhombus, and a polygonal shape may be sufficient. The shape of the light emitting portion plane of the cathode layer 15 formed in an island shape can be selected as appropriate in consideration of manufacturing convenience such as mask design and film formation.

  Thus, by forming the cathode layer 15 in an island shape, the perimeter per area of the light emitting unit plane can be shortened. Thereby, when the area of the light emitting portion plane of the cathode layer 15 is the same, the peripheral length of the light emitting portion plane can be shortened compared to the case where the shape of the light emitting portion plane of the cathode layer 15 is formed in a line shape or a lattice shape. Therefore, the light leaking from the periphery of the light emitting part (leakage light) can be minimized and the contrast of the display screen can be improved.

  Further, by forming the cathode layer 15 in an island shape, the cathode layer 15 can be made invisible to human eyes. That is, when the area of the light emitting part plane of the cathode layer 15 in the entire display device is the same, the smaller the pitch (arrangement interval) of the cathode layer 15, the less visible to the human eye. The peripheral length of the light emitting unit plane that causes light becomes long. However, by forming the shape of the light emitting portion plane of the cathode layer 15 in an island shape, the peripheral length of the light emitting portion plane can be shortened compared to the case where it is formed in a line shape or a lattice shape. And the contrast can be improved. Furthermore, when the line pitch is reduced in the line shape or the lattice shape, if the line pitch is reduced, the occupied area of light emission increases and the light use efficiency deteriorates. Such a problem can be solved by making the island shape.

  The anode layer 13 is made of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The organic layer 14 includes an electron transport layer, a light emitting layer, and a hole transport layer. The cathode layer 15 is, for example, an aluminum layer (Al layer) or a laminate including a magnesium layer (Mg layer) and a silver layer (Ag layer). The transparent electrode layer 18 is made of a transparent conductive material such as ITO or IZO. Here, it is preferable that the anode layer 13 has a thickness of 100 nm, the organic layer 14 has a thickness of 200 nm, and the cathode layer 15 has a thickness of 500 nm.

  A portion of the organic layer 14 sandwiched between the anode layer 13 and the cathode layer 15 is a light emitting region. That is, the organic layer 14 immediately below the cathode layer 15 is a light emitting region. The light emitting region emits light by applying a positive potential to the anode layer 13 and a negative potential to the cathode layer 15.

  Light traveling downward from the light emitting region is applied to the reflective liquid crystal display unit 300 through the transparent anode layer 13 and the first transparent substrate 10. Further, most of the light traveling upward from the light emitting region is reflected downward by the cathode layer 15 serving also as a light shielding layer and a reflective layer, and irradiated to the reflective liquid crystal display unit 300 through the transparent anode layer 13 and the first transparent substrate 10. The Therefore, it is possible to prevent the light from the light emitting region from directly entering the eyes of the observer who is above the illumination unit 200 and looking downward, and the contrast of the reflective liquid crystal display unit 300 can be increased.

  The anode layer 13 can be formed in a desired region by using a photo-etching technique after a transparent conductive material such as ITO or IZO is formed on the first transparent substrate 10. Further, the organic layer 14 and the cathode layer 15 can be formed in desired regions by a vapor deposition method using a mask.

  In addition, since the light emitting characteristics of the organic EL element 12 deteriorate due to the ingress of moisture, a desiccant layer 16 is provided on the surface of the second transparent substrate 20 so as to face the first transparent substrate 10 in order to prevent this. It is preferable to form. Moisture that has entered the sealed space through the seal layer 11 is absorbed by the desiccant layer 16.

  The desiccant layer 16 has a peripheral edge of the second transparent substrate 20 so as not to overlap with the organic EL device 12 in order to avoid blocking of external light incident on the organic EL device 12 through the second transparent substrate 20. It is preferable to form in a part. However, this is not the case when the desiccant layer 16 is made of a transparent material. In addition, an antireflection film 21 is preferably attached to the back surface of the second transparent substrate 20 in order to prevent reflection of external light.

  Further, as shown in FIG. 3, a resin having a refractive index equal to or approximately equal to the refractive index of the first transparent substrate in the space surrounded by the first transparent substrate 10, the transparent electrode layer 18 and the seal layer 11. 17 may be filled. Further, the resin 17 and the seal layer 11 may be integrally formed.

Thereby, the water | moisture content permeating through the seal layer 11 can be blocked reliably.
In the structure of FIG. 1, since an air layer exists between the organic EL element 12 and the transparent electrode layer 18, external light incident on the transparent electrode layer 18 from the second transparent substrate 20 is separated from the air layer and the transparent electrode. Reflected by the interface of the layer 18, the contrast of the liquid crystal display is deteriorated. On the other hand, according to the structure of FIG. 3, the external light incident on the transparent electrode layer 18 from the second transparent substrate 20 is not reflected on the interface of the transparent electrode layer 18 and enters the reflective liquid crystal display unit 300. Therefore, the contrast of the liquid crystal display is improved. In the structure of FIG. 3, the desiccant layer 16 of FIG. 1 may be provided.

  Next, the structure of the reflective liquid crystal display unit 300 illuminated by the illumination unit 200 and the coupling relationship with the illumination unit 200 will be described with reference to FIGS. 4 and 5. 4 is a plan view of a part of the pixel region 310 of the liquid crystal display unit 300, and FIG. 5 is a cross-sectional view taken along line XX of FIG.

  A switching thin film transistor 31 (hereinafter referred to as TFT) is formed in each of a plurality of pixels provided on a third transparent substrate 30 (TFT substrate) made of a glass substrate. The TFT 31 is covered with an interlayer insulating film 32, and a reflective pixel electrode 33 made of a reflective material such as aluminum (Al) is formed on the interlayer insulating film 32 corresponding to each TFT 31. The reflective pixel electrode 33 is connected to the drain or source of the corresponding TFT 31 through a contact hole CH formed in the interlayer insulating film 32.

  A fourth transparent substrate 34 (counter substrate) made of a glass substrate is disposed opposite to the third transparent substrate 30 on which the reflective pixel electrode 33 is formed. A common electrode 35 made of ITO is formed on the surface of the fourth transparent substrate 34. On the back surface of the fourth transparent substrate 34, a light scattering layer 36 composed of a diffusion adhesive layer and a polarizing plate 37 are laminated in this order. The polarizing plate 37 is a circular polarizing filter in which a λ / 4 retardation plate is bonded to the back surface of the linear polarizing filter. The light scattering layer 36 is for scattering light from the illumination unit 200 so that the pixel electrode 33 is uniformly irradiated. A liquid crystal layer 40 is sealed between the fourth transparent substrate 34 and the third transparent substrate 30. The liquid crystal layer 40 is optimally a VA (vertical alignment) method with excellent visual characteristics and contrast.

  According to the above-described configuration, the light emitted from the illumination unit 200 and the external light are circularly polarized by the polarizing plate 37, and further pass through the light scattering layer 36, the fourth transparent substrate 34, and the common electrode 35 to be a liquid crystal layer. 40 is reflected by the reflective pixel electrode 33. Here, when the liquid crystal layer 40 is a VA method and no voltage is applied, the polarization does not change even if it is transmitted through the liquid crystal layer 40. Therefore, the light reflected by the reflective pixel electrode 33 is Since the same path is reversed, it cannot pass through the circularly polarizing plate 37, so that black display is obtained. On the other hand, when a voltage is applied, the light transmittance changes for each pixel due to the electric field applied between the pixel electrode 33 and the common electrode 35. Thereby, the LCD display can be realized by changing the intensity of the light reflected by the reflective pixel electrode 33 for each pixel. The light from the LCD is visually recognized by an observer through a gap between the cathode layers 15 formed in an island shape.

  At this time, the light transmittance is changed for each pixel by the electric field applied between the pixel electrode 33 and the common electrode 35. Thereby, the LCD display can be realized by changing the intensity of the light reflected by the reflective pixel electrode 33 for each pixel. As described above, since the cathode layer 15 of the illumination unit 200 functions as a light shielding layer, light leakage from the light emitting region of the organic EL element 12 is prevented as much as possible, and the contrast of the liquid crystal display can be increased.

  The illuminating unit 200 is preferably disposed close to the reflective liquid crystal display unit 300. However, if an air layer exists between the irradiation unit 200 and the reflective liquid crystal display unit 300, when light emitted from the first transparent substrate 10 of the illumination unit 200 enters the air layer, There is a possibility that the light is reflected at the interface of the air layer and the reflected light returns to the observer side and the contrast is lowered.

  Therefore, by joining the irradiation device 200 and the reflective liquid crystal display unit 300 via a resin layer 45 (for example, a UV curable resin layer or a visible light curable resin layer) having the same refractive index as that of the first transparent substrate 10, It is preferable to prevent refraction of light.

  Next, the arrangement relationship between the illumination unit 200 and the pixels of the reflective LCD 300 will be described. As shown in FIG. 4, in the pixel region 310 of the reflective liquid crystal display unit 300, three types of pixels R, G, and B corresponding to the three primary colors of red, green, and blue are in the row direction (x) and the column direction (y). Is arranged. Although FIG. 4A shows a delta arrangement in which the pixels R, G, and B are shifted for each row, the present invention is not limited to this, and a stripe arrangement in which the pixels R, G, and B are arranged for each row may be used. The plurality of cathode layers 15 formed in an island shape of the illumination unit 200 are arranged side by side in the row direction (x) along the boundaries of the pixels R, G, and B.

  Each pixel has one TFT 31 and one reflective pixel electrode 33. The row pitch P1 of the cathode layer 15 of the illumination unit 200 is equal to the pixel row pitch P2. Further, the inter-column pitch Q1 of the cathode layer 15 of the illumination unit 200 is equal to the inter-pixel pitch Q2. Further, as shown in FIG. 4A, the cathode layer 15 of the illumination unit 200 is preferably disposed directly above the separation region SR of the reflective pixel electrode 33 that does not contribute to liquid crystal display. Accordingly, there is an advantage that most of the light reflected by the reflective pixel electrode 33 is visually recognized by the observer through the gaps between the plurality of cathode layers 15 without being blocked by the cathode layer 15.

On the other hand, the cathode layer 15 of the illumination unit 200 may be configured to be disposed immediately above the reflective pixel electrode 33. By forming the cathode layers 15 in the shape of islands, the arrangement pitch of the cathode layers 15 can be reduced to make the front light less visible to the human eye and with high luminous efficiency. The degree of freedom can be improved.
Further, as shown in FIG. 4B, the arrangement positions of the cathode layers 15 and the reflective pixel electrodes 33 may be different, and the corresponding positional relationship may be irregularly arranged.

  For example, the row pitch P1 of the cathode layer 15 of the illumination unit 200 is smaller than the pixel row pitch P2, and the ratio of the row pitch P1 of the cathode layer 15 to the pixel row pitch P2 (= P1 / P2) is 1 / natural number. It is good. When the inter-row pitch of the cathode layer 15 of the illumination unit 200 is the same as the inter-pixel pitch of the pixels, interference fringes and moire fringes are generated in the liquid crystal display. However, these phenomena can be prevented by setting in this way.

  Conversely, the inter-row pitch P1 of the cathode layer 15 of the illumination unit 200 is larger than the inter-pixel pitch P2, and the ratio (P1 / P2) of the inter-row pitch P1 of the cathode layer 15 to the inter-pixel pitch P2 is a natural number. It is good. By setting in this way, interference fringes and moire fringes can be prevented.

  Further, the inter-column pitch Q1 of the cathode layer 15 of the illumination unit 200 is smaller than the inter-column pitch Q2 of the pixels, and the ratio of the inter-column pitch Q1 of the cathode layer 15 to the inter-column pitch Q2 of the pixels (= Q1 / Q2). May be 1 / natural number. If the pitch between the columns of the cathode layer 15 and the pitch between the columns of the pixels are the same, interference fringes and moire fringes are generated in the liquid crystal display. it can.

  Conversely, the inter-column pitch Q1 of the cathode layer 15 of the illumination unit 200 is larger than the inter-column pitch Q2 of the pixels, and the ratio of the inter-column pitch Q1 of the cathode layer 15 to the inter-column pitch Q2 of the pixels (Q1 / Q2) may be a natural number. By setting in this way, interference fringes and moire fringes can be prevented.

  Furthermore, as shown in FIG. 4C, the pitch between the rows and / or the columns is designed to have two or more types of pitches on the display area of the display device, so that the pitch pattern of the cathode layer 15 can be obtained. Since two or more types of periodicity can be given to the above, interference fringes and moire fringes can be further prevented. In FIG. 4C, the pitch between the rows of the cathode layers 15 of the illumination unit 200 is designed with three types of pitches P1a, P1b, and P1c. Further, the pitch between the cathode layers 15 is designed with three kinds of pitches Q1a, Q1b, and Q1c.

  Further, the pitch pattern of the cathode layer 15 of the illumination unit 200 may be different for each design unit of the mask pattern. That is, in the case of LTPS (low temperature polysilicon), the design unit of the mask pattern is about 1 mm square at most, and pixels of about 10 to 20 μ × 30 to 50 μ per pixel are patterned in this design unit. design. Then, the design unit is copied according to the screen size of the display device to design a mask pattern. Therefore, as shown in FIG. 4D, a plurality of design units S1, S2, 33 having different pitch patterns of the cathode layer 15 of the illuminating unit 200 are prepared, and these are combined as appropriate, so that the cathode layer is within a range of 1 mm or more. Since the 15 pitch patterns have no periodicity, it is possible to prevent interference fringes and moire fringes from occurring due to interference between the pitch pattern of the cathode layer 15 of the illumination unit 200 and the pixel pitch pattern.

  The plurality of cathode layers 15 formed in the island shape of the illumination unit 200 may be arranged in an oblique direction with respect to the row direction (x). FIG. 6A shows an example in which a plurality of cathode layers 15 formed in an island shape of the illumination unit 200 are arranged in a 45 ° (135 °) direction oblique to the row direction (x). By setting in this way, interference fringes and moire fringes can be prevented. Furthermore, by making the pixel pitch (P2 and / or Q2) different from the arrangement pitch (P1a and / or Q1a) of the plurality of cathode layers 15 formed in the island shape of the illumination unit 200, interference fringes and moire fringes are further prevented. be able to.

  FIG. 6B shows an example in which the cathode layer is formed in a line shape. In the drawing, the cathode layer 15b formed in a line shape has an angle of 45 degrees (135 degrees) with respect to the row direction (x). Is arranged. By setting in this way, interference fringes and moire fringes can be prevented. Furthermore, by making the pixel pitch (P2 and / or Q2) different from the arrangement pitch (P1b and / or Q1b) of the plurality of cathode layers 15b formed in the line shape of the illumination unit 200, interference fringes and moire fringes are further prevented. be able to.

  FIG. 6C shows an example in which the cathode layer is formed in a lattice shape. In the drawing, the cathode layer 15c formed in the lattice shape is inclined at 45 degrees (135 degrees) with respect to the row direction (x). Is arranged. By setting in this way, interference fringes and moire fringes can be prevented. Furthermore, by making the pixel pitch (P2 and / or Q2) different from the arrangement pitch (P1c and / or Q1c) of the plurality of cathode layers 15b formed in the line shape of the illumination unit 200, interference fringes and moire fringes are further prevented. be able to.

  In addition, in FIG. 6, although the example which has arrange | positioned the cathode layer 15 in 45 degrees (135 degrees) diagonally with respect to row direction (x) was shown, if it is an angle which can suppress generation | occurrence | production of an interference fringe or a moire fringe, Other angles may be used.

Next, a display device according to a second embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a cross-sectional view showing the structure of the reflective liquid crystal display unit 300 and the coupling relationship with the illumination unit 200, and corresponds to the cross-sectional view along the line XX in FIG. The feature of this embodiment is that the first transparent substrate 10 and the fourth transparent substrate 34 of the first embodiment are combined to form one transparent substrate. That is, as shown in FIG. 6, the first transparent substrate 10 is deleted, and the organic EL element 12 is formed on the fourth transparent substrate 34. Thereby, the overall thickness of the display device can be reduced, and the cost can be reduced.

Next, a display device according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 9 is a sectional view of the entire display device. The anode layer 13 of the organic EL element 12 of the first embodiment (see FIG. 1) does not have an island pattern, whereas in this embodiment, the anode layer 13A of the organic EL element 12 is It has an island pattern.

  That is, a plurality of anode layers 13A having island-like patterns are formed on the first transparent substrate 10, and an organic layer 14 is formed so as to cover these anode layers 13A. A plurality of cathode layers 15 having the following pattern are formed. A plurality of cathode layers 15 </ b> A formed in an island shape and a plurality of anode layers 13 </ b> A formed in an island shape formed under these layers are overlapped. Other points are the same as those in the first embodiment.

  As in the first embodiment (FIG. 1), when the anode layer 13 made of ITO or IZO is formed in a pattern that is not separated into a plurality on the first transparent substrate 10, the second layer is formed due to the difference in refractive index. The external light incident through the transparent substrate 20 and the light generated by the organic EL element 12 are reflected by the anode layer 13 and the contrast of the liquid crystal display is lowered. On the other hand, according to this embodiment, the light passing between the island-shaped anode layers 13A is not affected by the reflection by the anode layer 13A. Therefore, the light transmittance can be increased and the contrast of the liquid crystal display can be improved.

  In the structure of FIG. 8, the desiccant layer 16 is formed on the surface of the second transparent substrate 20 so as to face the first transparent substrate 10, but as shown in FIG. A space surrounded by the substrate 10, the second transparent substrate 20, and the seal layer 11 may be filled with a resin 17 having a refractive index equal to that of the first transparent substrate.

  FIG. 10 is a cross-sectional view illustrating the structure of the reflective liquid crystal display unit 300 and the coupling relationship with the illumination unit 200, and corresponds to a cross-sectional view taken along line XX in FIG. The structure of the reflective liquid crystal display unit 300 is exactly the same as in the first embodiment. As described above, the line of the cathode layer 15 of the illuminating unit 200 is preferably disposed immediately above the separation region SR of the reflective pixel electrode 33 that does not contribute to the liquid crystal display. The cathode layer 15 is disposed below the line of the cathode layer 15. A portion of the organic layer 14 sandwiched between the line of the anode layer 13A and the line of the cathode layer 15 becomes a light emitting region. The line of the cathode layer 15 prevents light leakage generated in the light emitting region. However, by making the line width W1 of the cathode layer 15 larger than the line width W2 of the anode layer 13A, light leakage is prevented. The contrast of the liquid crystal display can be further improved with less.

  Next, a display device according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view illustrating the structure of the reflective liquid crystal display unit 300 and the coupling relationship with the illumination unit 200, and corresponds to the cross-sectional view along the line XX in FIG. The feature of this embodiment is that the first transparent substrate 10 and the fourth transparent substrate 34 of the third embodiment are combined to form one transparent substrate. That is, as shown in FIG. 11, the first transparent substrate 10 is deleted, and the organic EL element 12 is formed on the fourth transparent substrate 34. Thereby, the overall thickness of the display device can be reduced, and the cost can be reduced.

  Next, a display device according to a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 12 is a sectional view of the entire display device. The anode layer 13 and the organic layer 14 of the organic EL element 12 of the first embodiment (see FIG. 1) do not have an island-shaped pattern, whereas in this embodiment, the anode of the organic EL element 12 Each of the layer 13A and the organic layer 14A has an island pattern.

  That is, a plurality of anode layers 13A having island-shaped patterns are formed on the first transparent substrate 10, and a plurality of organic layers 14A having island-shaped patterns are stacked on the anode layers 13A. A plurality of cathode layers 15 having a similar island pattern are formed on 14A. The plurality of cathode layers 15A, the plurality of organic layers 14A formed under them, and the plurality of anode layers 13A are superposed. Other points are the same as those in the first embodiment.

  When the anode layer 13 made of ITO or IZO is formed in a non-line pattern on the first transparent substrate 10 as in the first embodiment (FIG. 1), the second transparent substrate 20 is caused by the difference in refractive index. The external light incident through the light and the light generated by the organic EL element 12 are reflected by the anode layer 13 and the contrast of the liquid crystal display is lowered. Further, similar reflection occurs with respect to the organic layer 14.

  On the other hand, according to the present embodiment, the light passing between the anode layer 13A and the organic layer 14A formed in an island shape is not affected by reflection by these layers. Therefore, the light transmittance can be increased and the contrast of the liquid crystal display can be improved.

  Further, in the structure of FIG. 12, the desiccant layer 16 is formed on the surface of the second transparent substrate 20 so as to face the first transparent substrate 10, but as shown in FIG. A space surrounded by the substrate 10, the second transparent substrate 20, and the seal layer 11 may be filled with a resin 17 having a refractive index equal to that of the first transparent substrate.

  FIG. 14 is a cross-sectional view illustrating the structure of the reflective liquid crystal display unit 300 and the coupling relationship with the illumination unit 200, and corresponds to a cross-sectional view taken along line XX of FIG. The structure of the reflective liquid crystal display unit 300 is exactly the same as in the first embodiment. As described above, the cathode layer 15 of the illumination unit 200 is preferably disposed immediately above the separation region SR of the reflective pixel electrode 33 that does not contribute to liquid crystal display. In this case, the organic layer 14A and the anode layer 13A are also included. Overlying the cathode layer 15 is disposed. The organic layer 14A sandwiched between the anode layer 13A and the cathode layer 15 serves as a light emitting region. The cathode layer 15 prevents light leakage generated in the light emitting region. However, by making the width W1 of the cathode layer 15 larger than the width W3 of the organic layer 14A and the width W4 of the anode layer 13A, light leakage occurs. It is possible to further improve the contrast of the liquid crystal display by reducing the amount of.

  Further, as shown in FIG. 15, it is preferable that the distance L between the edge of the cathode layer 15 and the edge of the organic layer 14A is larger than the thickness T of the organic layer 14A in order to further reduce light leakage. Further, the width W3 of the organic layer 14A may be larger than the line width W4 of the anode layer 13A.

  Next, a display device according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 16 is a cross-sectional view showing the structure of the reflective liquid crystal display unit 300 and the coupling relationship with the illumination unit 200, and corresponds to the cross-sectional view along the line XX in FIG. The feature of this embodiment is that the first transparent substrate 10 and the fourth transparent substrate 34 of the fifth embodiment are used as one transparent substrate. That is, as shown in FIG. 16, the first transparent substrate 10 is deleted, and the organic EL element 12 is formed on the fourth transparent substrate 34. Thereby, the overall thickness of the display device can be reduced, and the cost can be reduced.

  The cathode layer 15 can be arranged on the reflective pixel electrode 33 other than the separation region SR by adjusting the pitch. The pattern of the cathode layer 15 may be a mesh pattern other than the pattern.

  In the fifth and sixth embodiments, as shown in FIG. 17, the cathode layer 15 may be formed so as to cover the organic layer 14 and the anode layer 13.

  In the above-described embodiment, an organic EL display using an organic substance such as diamine is shown as electroluminescence. However, the present invention is not limited to this, and an inorganic EL display using an inorganic substance such as zinc sulfide may be used. Further, a light source other than electroluminescence may be used as long as the light source has a similar effect.

  In the above-described embodiment, the bottom emission type organic electroluminescence element is adopted as the front light. However, the present invention is not limited to this, and the top emission type organic electroluminescence element may be adopted as the front light.

1 is a first cross-sectional view of a display device according to a first embodiment of the present invention. It is a partial top view of the illumination part 200 which shows the light emission part planar shape of the cathode layer 15 which concerns on this invention. It is a 2nd sectional view of the display concerning a 1st embodiment of the present invention. 4 is a plan view of a part of a pixel region 310 of a reflective liquid crystal display unit 300. FIG. FIG. 5 is a cross-sectional view taken along line XX in FIG. 4. 4 is a plan view of a part of a pixel region 310 of a reflective liquid crystal display unit 300. FIG. It is sectional drawing of the display apparatus which concerns on the 2nd Embodiment of this invention. It is a 1st sectional view of a display concerning a 3rd embodiment of the present invention. It is 2nd sectional drawing of the display apparatus which concerns on the 3rd Embodiment of this invention. It is a 3rd sectional view of a display concerning a 3rd embodiment of the present invention. It is sectional drawing of the display apparatus which concerns on the 4th Embodiment of this invention. It is a 1st sectional view of a display concerning a 5th embodiment of the present invention. It is 2nd sectional drawing of the display apparatus which concerns on the 5th Embodiment of this invention. It is the 3rd sectional view of the display concerning the 5th embodiment of the present invention. It is sectional drawing of the organic EL element of the display apparatus which concerns on the 5th Embodiment of this invention. It is sectional drawing of the display apparatus which concerns on the 6th Embodiment of this invention. 3 is a cross-sectional view of an organic EL element 12. FIG. It is a figure which shows the reflection type LCD provided with the front light.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st transparent substrate 11 Seal layer 12 Organic EL element 13 Anode layer 14 Organic layer 15 Cathode layer 16 Desiccant layer 17 Resin 20 Second transparent substrate 21 Antireflection layer 30 Third transparent substrate 31 Thin film transistor (TFT)
32 Interlayer insulating film 33 Pixel electrode 34 Fourth transparent substrate 35 Common electrode 36 Light scattering layer 37 Polarizing plate 40 Liquid crystal layer 45 Resin layer 200 Illumination unit 300 Liquid crystal display unit

Claims (12)

A display unit that includes a liquid crystal and a pair of electrodes that drive the liquid crystal, and changes the intensity of light incident on the liquid crystal from the observation side by an electric field applied between the electrodes, and reflects and outputs the light to the observation side ; An illumination unit that is provided on the display unit and emits light from the observation side toward the display unit ,
The illumination unit includes a transparent electrode layer disposed on the display unit, a light emitting layer disposed on the transparent electrode layer, and a reflective electrode layer disposed on the light emitting layer,
The cross-sectional view, wherein the distance between the edge of the reflective electrode layer and the edge of the light emitting layer is larger than the thickness of the light emitting layer . The display unit includes a plurality of pixels in which reflective pixel electrodes that receive light generated from the light emitting unit are disposed, and the row pitch and / or the column pitch of the illumination unit have a plurality of types of pitches. The display device according to claim 1, wherein: A display unit that includes a liquid crystal and a pair of electrodes that drive the liquid crystal, and changes the intensity of light incident on the liquid crystal from the observation side by an electric field applied between the electrodes, and reflects and outputs the light to the observation side ; An illumination unit that is provided on the display unit and emits light from the observation side toward the display unit ,
The illumination unit includes a first substrate having a back surface disposed on the display unit;
A second substrate bonded to the first substrate via a sealing layer;
A light-emitting portion comprising an electroluminescence element disposed between the first substrate and the second substrate,
The display unit includes a plurality of pixels, and a third substrate in which a reflective pixel electrode that receives light generated from the light emitting unit is formed in each pixel;
A fourth substrate disposed on the third substrate and having a common electrode formed on a surface thereof;
A liquid crystal layer sealed between the third substrate and the fourth substrate,
The illumination unit includes a transparent electrode layer disposed on the display unit, a light emitting layer disposed on the transparent electrode layer, and a reflective electrode layer disposed on the light emitting layer,
The cross-sectional view, wherein the distance between the edge of the reflective electrode layer and the edge of the light emitting layer is larger than the thickness of the light emitting layer . 4. The display device according to claim 3, wherein a pitch between rows and / or a pitch between columns of the light emitting units made of the electroluminescence elements has a plurality of types of pitches. The display device according to any one of claims 1 to 4 , wherein the row pitch and / or the column pitch of the light emitting units are arranged in a range of 1 mm or more so as not to have periodicity. The light emitting unit, a display device according to any one of claims 1 to 5, characterized in that an island-shaped pattern. The light emitting unit, a display device according to any one of claims 1 to 6, which is a line-shaped pattern. The light emitting unit, a display device according to any one of claims 1 to 7, characterized in that a grid-like pattern. The light emitting unit, a display device according to any one of claims 1 to 8, characterized in that an organic electroluminescent device or an inorganic electroluminescent device. A liquid crystal and a pair of electrodes for driving the liquid crystal, and a display unit that changes the intensity of light incident on the liquid crystal from the observation side by an electric field applied between the electrodes and reflects and outputs the light to the observation side A lighting device arranged on the observation side of the display device ,
The lighting device includes a transparent substrate and a light emitting unit arranged on the transparent substrate,
The illumination unit includes a transparent electrode layer disposed on the display unit, a light emitting layer disposed on the transparent electrode layer, and a reflective electrode layer disposed on the light emitting layer,
The lighting device , wherein the distance between the edge of the reflective electrode layer and the edge of the light emitting layer is larger than the thickness of the light emitting layer in a cross-sectional view . A liquid crystal and a pair of electrodes for driving the liquid crystal, and a display unit that changes the intensity of light incident on the liquid crystal from the observation side by an electric field applied between the electrodes and reflects and outputs the light to the observation side A lighting device arranged on the observation side of the display device ,
The lighting device includes a first substrate having a back surface disposed on the display device;
A second substrate bonded to the first substrate via a sealing layer;
A light-emitting portion that is disposed between the first substrate and the second substrate and includes an electroluminescence element that irradiates light to the reflective pixel electrode of the display layer;
The illumination unit includes a transparent electrode layer disposed on the display unit, a light emitting layer disposed on the transparent electrode layer, and a reflective electrode layer disposed on the light emitting layer,
The lighting device , wherein the distance between the edge of the reflective electrode layer and the edge of the light emitting layer is larger than the thickness of the light emitting layer in a cross-sectional view . The light emitting section includes a light shielding section on the surface on the observation side, the other surface is disposed to face the display section of the display device, and irradiates the display section with light. Item 12. The illumination device according to Item 10 or 11.

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