Display unit and method for controlling display unit

Abstract

To provide a display unit that can accurately detect deterioration of a liquid crystal panel.SOLUTION: A display unit has: a liquid crystal panel that comprises a first substrate and a second substrate provided facing each other, and a liquid crystal layer provided between the first substrate and the second substrate, and has a first surface directed to a normal direction of the first substrate and on which light in a first wavelength region is incident, and a second surface intersecting the first surface; and a light detection unit that, when the light in the first wavelength region is incident on the liquid crystal layer, detects light emitted from the second surface and in a longer wavelength region than the first wavelength region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a display device and a method for controlling the display device. [Background technology]

[0002] In projection display devices, light emitted from a light source is irradiated onto a transmissive or reflective liquid crystal panel, and the transmitted or reflected light is modulated by the liquid crystal panel and projected onto a screen. In such display devices, high-intensity light is irradiated onto the liquid crystal panel from the light source, which can cause deterioration of the liquid crystal panel.

[0003] For example, Patent Document 1 describes a liquid crystal display device that uses an optical sensor to detect the chromaticity or illuminance of a light beam emitted from a liquid crystal panel, and controls a cooling means by determining the image quality state of an optical image based on the detection results. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-40016 Summary of the Invention [Problem to be solved by the invention]

[0005] In such display devices, it is desirable to accurately detect the degree of deterioration of the liquid crystal panel. [Means for solving the problem]

[0006] One aspect of the display device according to the present invention is a liquid crystal panel including a first substrate and a second substrate disposed opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal panel having a first surface oriented in a normal direction of the first substrate and onto which light in a first wavelength range is incident, and a second surface intersecting the first surface; a light detection unit that detects light in a wavelength range longer than the first wavelength range that is emitted from the second surface when light in a first wavelength range is incident on the liquid crystal layer; It has.

[0007] One aspect of the display device control method according to the present invention includes: A method for controlling a display device having a liquid crystal panel including a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel having a first surface oriented in a normal direction of the first substrate and onto which light in a first wavelength range is incident, and a second surface intersecting with the first surface, the method comprising: When light in a first wavelength range is incident on the liquid crystal layer, light in a wavelength range longer than the first wavelength range that is emitted from the second surface is detected. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically showing a display device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically illustrating a light modulation device and a light detection device of the display device according to the embodiment. [Figure 3] FIG. 2 is a plan view schematically showing a liquid crystal panel of the display device according to the embodiment. [Figure 4] FIG. 2 is a cross-sectional view schematically showing a liquid crystal panel of the display device according to the embodiment. [Figure 5] FIG. 1 is a cross-sectional view schematically showing a display device according to an embodiment of the present invention. [Figure 6] FIG. 1 is a side view schematically showing a display device according to an embodiment of the present invention. [Figure 7] 10 is a graph illustrating the change over time in photoluminescence when blue light is irradiated onto a liquid crystal layer. [Figure 8] 10 is a graph illustrating changes in photoluminescence over time in an accelerated deterioration test of a liquid crystal panel. [Figure 9] 10 is a graph illustrating changes in photoluminescence over time in an accelerated deterioration test of a liquid crystal panel. [Figure 10] 4 is a graph illustrating the electro-optical characteristics of a liquid crystal panel. [Figure 11]6 is a flowchart illustrating processing by a deterioration determination unit of the display device according to the embodiment. [Figure 12] FIG. 10 is a cross-sectional view schematically showing a display device according to a first modified example of the embodiment. [Figure 13] FIG. 10 is a side view schematically showing a display device according to a first modified example of the embodiment. [Figure 14] FIG. 10 is a diagram schematically illustrating a light modulation device and a light detection device of a display device according to a second modified example of the present embodiment. [Figure 15] FIG. 10 is a side view schematically showing a display device according to a second modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0010] 1. Display device 1.1. Overall structure First, a display device 100 according to this embodiment will be described with reference to the drawings. Fig. 1 is a diagram schematically showing a display device 100 according to this embodiment.

[0011] 1, the display device 100 includes, for example, a light source device 10, dichroic mirrors 20 and 22, reflecting mirrors 24, 26, and 28, relay lenses 30, 32, 34, 36, and 38, light modulation devices 40R, 40G, and 40B, a cross dichroic prism 50 serving as a light combining device, a projection optical system 60, a light detection device 70, a housing 80, a light source control unit 90, a detection signal processing unit 91, and a central control unit 92. The display device 100 is, for example, a 3LCD (Liquid Crystal Display) type projector.

[0012] Although not shown, the light source device 10 includes, for example, a light source and an optical system. The light source is, for example, an array light source having a semiconductor laser, or a lamp unit configured with a white light source such as an ultra-high pressure mercury lamp or a halogen lamp. Light from the light source is incident on the optical system. The optical system is, for example, an integrator lens that improves the uniformity of the light from the light source.

[0013] Dichroic mirror 20 transmits red light (R) and reflects green light (G) and blue light (B) out of the light emitted from light source device 10. Dichroic mirror 22 reflects the green light (G) reflected by dichroic mirror 20 and transmits the blue light (B).

[0014] The red light (R) transmitted through the dichroic mirror 20 is reflected by the reflecting mirror 24 and then passes through the relay lens 30 before entering the optical modulation device 40R. The green light (G) reflected by the dichroic mirror 22 passes through the relay lens 32 and enters the optical modulation device 40G. The blue light (B) transmitted through the dichroic mirror 22 passes through the relay lens 34, the reflecting mirror 26, the relay lens 36, the reflecting mirror 28, and the relay lens 38 before entering the optical modulation device 40B.

[0015] The light modulation devices 40R, 40G, and 40B are disposed opposite the light incident surfaces for the respective color lights of the cross dichroic prism 50. The light modulation devices 40R, 40G, and 40B modulate the incident color lights based on video information (video signals).

[0016] The colored lights modulated by the light modulation devices 40R, 40G, and 40B are each emitted toward the cross dichroic prism 50. In the example shown in the figure, each of the light modulation devices 40R, 40G, and 40B is provided between a first polarizing element 41a and a second polarizing element 41b. Details of the light modulation devices 40R, 40G, and 40B will be described later.

[0017] The cross dichroic prism 50 is made by bonding four right-angle prisms together, and on the inner surfaces of the prisms, a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged in a cross shape. These dielectric multilayer films combine the three colored lights to generate light that represents a color image. The light combined by the cross dichroic prism 50 is emitted toward the projection optical system 60.

[0018] The projection optical system 60 projects the combined light that has entered it onto the screen 2. The image is enlarged and displayed on the screen 2. The projection optical system 60 is made up of, for example, multiple lenses, namely, a biconvex lens 62, a biconcave lens 64, and a biconvex lens 66.

[0019] The photodetector 70 is provided on the side of the light modulation device 40B. When blue light is incident on the liquid crystal panel 41 of the light modulation device 40B, the photodetector 70 detects light emitted from the side of the light modulation device 40B. Details of the photodetector 70 will be described later.

[0020] The housing 80 accommodates, for example, the light source device 10, the dichroic mirrors 20 and 22, the reflecting mirrors 24, 26 and 28, the relay lenses 30, 32, 34, 36 and 38, the light modulation devices 40R, 40G and 40B, the cross dichroic prism 50, and the projection optical system 60. The material of the housing 80 is, for example, metal or resin.

[0021] The light source control unit 90 is electrically connected to the light source of the light source device 10. The light source control unit 90 controls the light source of the light source device 10. The light source control unit 90 generates a drive signal based on a signal from the central control unit 92, and transmits the generated drive signal to the light source of the light source device 10.

[0022] The detection signal processing unit 91 is electrically connected to the photodetector 70. The detection signal processing unit 91 acquires the detection signal from the photodetector 70 and transmits the acquired detection signal to the central control unit 92.

[0023] The central control unit 92 controls the light source of the light source device 10 via the light source control unit 90. Furthermore, the central control unit 92 acquires a detection signal from the light detection device 70 via a detection signal processing unit 91. The light source control unit 90, the detection signal processing unit 91, and the central control unit 92 are configured to include, for example, an integrated circuit (IC).

[0024] The central control unit 92 has a deterioration determination unit 93. The deterioration determination unit 93 determines the degree of deterioration of the liquid crystal panel 42 of the light modulation device 40B based on the acquired detection signal. Specific processing by the deterioration determination unit 93 will be described later.

[0025] In addition to projectors, the display device 100 can also be used in, for example, liquid crystal panels of photocurable 3D printers, EVFs (Electrical View Finders), mobile mini projectors, head-up displays, smartphones, mobile phones, mobile computers, digital cameras, digital video cameras, displays, in-vehicle equipment, audio equipment, exposure equipment, etc. The present invention is applicable to various electronic devices such as lighting equipment.

[0026] 1.2. Optical Modulation Device Fig. 2 is a diagram schematically illustrating an optical modulation device 40 B. In Fig. 2, an X-axis, a Y-axis, and a Z-axis are illustrated as three axes that are orthogonal to one another.

[0027] 2, the light modulation device 40B has a liquid crystal panel 42, a COF (Chip On Film) 44, and a holder 46. The liquid crystal panel 42 modulates incident light based on video information. The liquid crystal panel 42 is an active-drive liquid crystal panel having a thin film transistor (TFT) as a transistor for each pixel.

[0028] Fig. 3 is a plan view schematically showing the liquid crystal panel 42. Fig. 4 is a cross-sectional view taken along line IV-IV' in Fig. 3, schematically showing the liquid crystal panel 42.

[0029] As shown in FIGS. 3 and 4, the liquid crystal panel 42 includes, for example, an element substrate 110, a sealant 120, a liquid crystal layer 130, and an opposing substrate 140.

[0030] 3, the element substrate 110 is larger than the counter substrate 140 when viewed from the normal direction of the element substrate 110 of the light modulation device 40B (hereinafter simply referred to as "viewed from the normal direction"). The planar shape of the element substrate 110 is, for example, a rectangle. In the example shown in FIG. 4, the normal direction is the direction in which a normal N to the surface of the first support substrate 112 of the element substrate 110 facing the liquid crystal layer 130 extends, which is the Z-axis direction. In the example shown, the normal direction is also the stacking direction of the element substrate 110 and the liquid crystal layer 130.

[0031] The sealant 120 bonds the element substrate 110 and the counter substrate 140. The sealant 120 is provided along the outer edge of the counter substrate 140. When viewed from the normal direction, the sealant 120 surrounds the liquid crystal layer 130. The sealant 120 is, for example, an adhesive such as a thermosetting, photosetting, or electron beam curing epoxy resin. A display region E including a plurality of pixels P arranged in a matrix is ​​provided inside the sealant 120. The display region E is surrounded by a peripheral region F. In the peripheral region F, a parting portion 142 is provided between the sealant 120 and the display region E, surrounding the display region E. The parting portion 142 is made of, for example, a light-shielding metal or metal oxide.

[0032] The element substrate 110 includes, for example, an external connection terminal 101, a data line driving circuit 102, an inspection circuit 103, a scanning line driving circuit 104, a first wiring 105, and a second wiring 106.

[0033] A plurality of external connection terminals 101 are provided. In the illustrated example, the plurality of external connection terminals 101 are arranged in the X-axis direction. The data line driving circuit 102 is provided between a first side along the plurality of external connection terminals 101 and the sealing material 120. The inspection circuit 103 is provided between the display area E and the sealing material 120 along a second side opposite to the first side. The scanning line driving circuit 104 is provided between the display area E and the sealing material 120 along third and fourth sides perpendicular to the first side and opposite to each other. Although not illustrated, the inspection circuit 103 may be provided between the display area E and the sealing material 120 along the data line driving circuit 102.

[0034] The first wiring 105 is provided between the sealant 120 along the second side and the inspection circuit 103. The first wiring 105 is connected to two scanning line driving circuits 104. A plurality of first wirings 105 are provided. The second wiring 106 is connected to the data line driving circuit 102 and the scanning The second wiring 106 is connected to a line driving circuit 104. The second wiring 106 is electrically connected to a plurality of external connection terminals 101. A plurality of second wirings 106 are provided.

[0035] As shown in FIG. 4, the element substrate 110 includes, for example, a first support substrate 112, pixel electrodes 114, TFTs 116, and a first alignment layer 118.

[0036] The first support substrate 112 supports the pixel electrodes 114, the TFTs 116, and the first alignment layer 118. The first support substrate 112 is, for example, a glass substrate, a quartz substrate, etc. The first support substrate 112 transmits light emitted from the light source.

[0037] The pixel electrodes 114 and the TFTs 116 are provided on the liquid crystal layer 130 side of the first support substrate 112. A pixel electrode 114 and a TFT 116 are provided for each pixel P. A plurality of pixel electrodes 114 and TFTs 116 are provided corresponding to a plurality of pixels P. The pixel electrodes 114 and the TFTs 116 constitute a pixel P. The pixel electrodes 114 are transparent electrodes made of, for example, ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The TFTs 116 are switching elements.

[0038] The first alignment layer 118 is provided on the liquid crystal layer 130 side of the first support substrate 112. The first alignment layer 118 covers the pixel electrodes 114, the TFTs 116, and the first wiring 105. The first alignment layer 118 is, for example, an inorganic alignment layer such as a silicon oxide layer, or an organic alignment layer such as a polyimide layer.

[0039] The liquid crystal layer 130 is provided between the element substrate 110 and the counter substrate 140. The liquid crystal layer 130 is formed by sealing liquid crystal having positive or negative dielectric anisotropy in the gap between the element substrate 110 and the counter substrate 140.

[0040] The counter substrate 140 is provided on the side of the liquid crystal layer 130 opposite to the element substrate 110. The counter substrate 140 faces the element substrate 110. Light emitted from a light source is incident on the counter substrate 140.

[0041] The counter substrate 140 includes, for example, a second support substrate 141, a parting portion 142, an insulating layer 143, a counter electrode 144, and a second alignment layer 145.

[0042] The second support substrate 141 faces the first support substrate 112. The second support substrate 141 supports the parting portion 142 and the insulating layer 143. The second support substrate 141 is, for example, a glass substrate or a quartz substrate. The second support substrate 141 transmits light emitted from the light source. When viewed from the normal direction, the area of ​​the second support substrate 141 is, for example, smaller than the area of ​​the first support substrate 112.

[0043] The parting portion 142 is provided on the liquid crystal layer 130 side of the second support substrate 141. As shown in FIG. 3, the parting portion 142 overlaps with the inspection circuit 103 and the scanning line driving circuit 104 when viewed from the normal direction. The parting portion 142 blocks light incident from the counter substrate 140 side from entering peripheral circuits such as the inspection circuit 103 and the scanning line driving circuit 104. This makes it possible to suppress malfunction of the peripheral circuits. Furthermore, the parting portion 142 reduces the incidence of unnecessary stray light into the display region E. This makes it possible to suppress a decrease in the contrast of the liquid crystal panel 42.

[0044] As shown in FIG. 4, the insulating layer 143 is provided on the liquid crystal layer 130 side of the second support substrate 141. The insulating layer 143 covers the parting portion 142. The insulating layer 143 is provided between the liquid crystal layer 130 and the second support substrate 141. The surface of the insulating layer 143 on the liquid crystal layer 130 side is For example, it is a flat surface. The insulating layer 143 transmits light emitted from the light source. The insulating layer 143 is, for example, a silicon oxide layer.

[0045] The counter electrode 144 is provided on the liquid crystal layer 130 side of the insulating layer 143. The counter electrode 144 is provided between the liquid crystal layer 130 and the insulating layer 143. The counter electrode 144 is a transparent electrode made of, for example, ITO or IZO.

[0046] The second alignment layer 145 is provided on the liquid crystal layer 130 side of the counter electrode 144. The liquid crystal layer 130 is provided between the first alignment layer 118 and the second alignment layer 145. The second alignment layer 145 is, for example, an inorganic alignment layer such as a silicon oxide layer, or an organic alignment layer such as a polyimide layer.

[0047] The liquid crystal panel 42 employs optical designs for a normally white mode or a normally black mode. In the normally white mode, the transmittance of the pixel P when no voltage is applied is greater than the transmittance when a voltage is applied. In the normally black mode, the transmittance of the pixel P when no voltage is applied is less than the transmittance when a voltage is applied. Note that although the liquid crystal panel 42 is a transmissive type in the example shown in FIG. 1, it may also be a reflective type.

[0048] 5 is a cross-sectional view taken along line VV' in FIG. 2, schematically illustrating the display device 100. However, for convenience of illustration, the view shows the light guide section 71 of the photodetector 70 from the sealing material 120 on the V side. In addition, FIG. 5 omits illustration of components other than the liquid crystal panel 42, the light guide section 71 of the photodetector 70, and the index matching material 4. Also, FIG. 5 illustrates the liquid crystal panel 42 in a simplified form.

[0049] As shown in FIG. 5 , the liquid crystal panel 42 further includes, for example, a first dustproof substrate 150 and a second dustproof substrate 152. The first dustproof substrate 150 is provided on the side of the element substrate 110 opposite the liquid crystal layer 130. The element substrate 110 is provided between the first dustproof substrate 150 and the liquid crystal layer 130. The second dustproof substrate 152 is provided on the side of the counter substrate 140 opposite the liquid crystal layer 130. The counter substrate 140 is provided between the second dustproof substrate 152 and the liquid crystal layer 130. The dustproof substrates 150 and 152 transmit light from the light source. The dustproof substrates 150 and 152 are made of, for example, glass. The dustproof substrates 150 and 152 are used to make dust invisible because dust adhering to their surfaces causes the image to become out of focus.

[0050] The liquid crystal panel 42 has a first surface 42a onto which blue light BL is incident, and a second surface 42b intersecting with the first surface 42a. In the illustrated example, the first surface 42a is formed by the second dustproof substrate 152. The first surface 42a is a surface facing the normal direction. In the illustrated example, the first surface 42a is facing the +Z-axis direction. The second surface 42b is connected to the first surface 42a. In the illustrated example, the second surface 42b is perpendicular to the first surface 42a. The second surface 42b is a surface facing a direction perpendicular to the normal direction. In the illustrated example, the second surface 42b is facing the +X-axis direction. The second surface 42b is a side surface of the liquid crystal panel 42.

[0051] 2, the COF 44 is connected to the liquid crystal panel 42. The COF 44 has a drive IC 44a that drives the liquid crystal panel 42. The COF 44 also has a connector 44b. The connector 44b may be configured to include a reinforcing plate. Although not shown, the connector 44b may be connected to a circuit board 94.

[0052] The holder 46 supports the liquid crystal panel 42. In other words, the holder 46 houses the liquid crystal panel 42. The end of the COF 44 opposite the connector 44b is typically inserted into a recess provided in the holder 46. The holder 46 is made of a material such as metal or resin.

[0053] An opening 46a is formed in the holder 46. When viewed from the normal direction, the opening 46a overlaps with the display area E of the liquid crystal panel 42. The opening 46a is formed on the second dustproof substrate 152 side. Although not shown, for example, an opening that overlaps with the display area E when viewed from the normal direction is formed on the second dustproof substrate 152 side.

[0054] Bolt holes 46b are formed in the holder 46. In the illustrated example, four bolt holes 46b are formed. Bolts (not shown) are inserted into the bolt holes 46b. The bolts support the holder 46 within the housing 80, enabling precise alignment with the cross dichroic prism 50.

[0055] Fig. 6 is a side view schematically showing the display device 100, as seen from the direction of arrow VI in Fig. 2. For convenience, Fig. 6 omits illustration of components other than the liquid crystal panel 42 and the holder 46. Fig. 6 also simplifies the illustration by showing the liquid crystal panel 42 as a perspective broken line. In other words, when viewed from the direction of arrow VI in Fig. 2, the liquid crystal panel 42 is basically hidden by the holder 46 and cannot be seen. This also applies to Figs. 13 and 15 described below.

[0056] As shown in FIGS. 2 and 6, a through-hole 46c is formed in the holder 46. The through-hole 46c is located on a side of the liquid crystal panel 42 and is provided in the holder 46. As shown in FIG. 2, the display area E of the liquid crystal panel 42 has a shape having a long side and a short side when viewed from the normal direction. The shape of the display area E is, for example, a rectangle having a long side Ea and a short side Eb. The through-hole 46c is provided on the short side Eb side of the display area E. When viewed from the normal direction, the through-hole 46c overlaps with the second surface 42b of the liquid crystal panel 42, which forms the short side Eb. The through-hole 46c is, for example, chamfered. This facilitates the insertion of the light guide unit 71 into the through-hole 46c. In the example shown in FIG. 6, the through-hole 46c overlaps with the second dustproof substrate 152 when viewed from the X-axis direction. The through-hole 46c does not overlap with the liquid crystal layer 130 when viewed from the X-axis direction. Although not shown, the through-hole 46c may overlap the counter substrate 140 as long as it does not overlap the liquid crystal layer 130.

[0057] The above describes the liquid crystal panel 42 of the optical modulation device 40B, but except for the through hole 46c formed in the holder 46, the configuration of the liquid crystal panel 42 of the optical modulation devices 40R and 40G is basically the same as the configuration of the liquid crystal panel 42 of the optical modulation device 40B.

[0058] 1.3. Photodetector As shown in FIG. 2, the light detection device 70 includes, for example, a light guide unit 71 and a light detector 73.

[0059] The light guide 71 is, for example, an optical fiber. The light guide 71 is, for example, linear in shape. The light guide 71 is made of, for example, a hard material such as glass. One end of the light guide 71 is inserted into a through hole 46c formed in the holder 46. A light incident surface 72a of the light guide 71 constitutes one end of the light guide 71. The light incident surface 72a of the light guide 71 is provided on the short side Eb of the liquid crystal panel 42. The light incident surface 72a is provided along the short direction of the liquid crystal panel 42. The other end of the light guide 71 is inserted into a support portion 76 of the photodetector 73. A light exit surface 72b of the light guide 71 constitutes the other end of the light guide 71.

[0060] 5, the light guide 71 has a core 71a and a clad 71b surrounding the core 71a. When blue light BL is incident on the liquid crystal layer 130, the light guide 71 guides light PL emitted from the deterioration substances 132 in the liquid crystal layer 130 to a photodetector 73. Specifically, the light PL enters the light guide 71 from a light incident surface 72a of the light guide 71, passes through the light guide 71 while being reflected at the boundary between the core 71a and the clad 71b, and exits from a light exit surface 72b of the light guide 71. The light is incident on the light detection portion 74 of the photodetector 73 .

[0061] As shown in FIG. 5, deterioration substances 132 are generated in the liquid crystal layer 130 as the liquid crystal layer 130 is used and light is incident thereon. The deterioration substances 132 are substances generated by irradiating the liquid crystal layer 130 with blue light BL. When the blue light BL is incident on the liquid crystal layer 130, the deterioration substances 132 emit light PL. The light PL includes light with a longer wavelength range than the blue light BL. The wavelength of the light PL includes, for example, a wavelength range of 550 nm to 650 nm. The wavelength of the blue light BL is, for example, 430 nm to 490 nm. The light PL is, for example, red light. The light PL is photoluminescence (phosphorescence) in the deterioration substances 132. The light PL is emitted approximately isotropically from the deterioration substances 132.

[0062] The light incident surface 72a of the light guide unit 71 faces the second surface 42b of the liquid crystal panel 42. In the illustrated example, the second surface 42b includes the surface of the element substrate 110, the surface of the sealant 120, the surface of the counter substrate 140, and the surfaces of the dustproof substrates 150 and 152. Furthermore, the second surface 42b may include the surfaces of the alignment layers 118 and 145 and the surface of the counter electrode 144. The light incident surface 72a is, for example, parallel to the second surface 42b. In the illustrated example, the light guide unit 71 is provided so as to be parallel to the X-axis.

[0063] An index matching material 4 is disposed between the light incident surface 72a of the light guide unit 71 and the second surface 42b of the liquid crystal panel 42. The display device 100 has the index matching material 4. The difference in refractive index between the index matching material 4 and the core 71a is smaller than the difference in refractive index between air and the core 71a. The index matching material 4 is made of, for example, a silicon-based material. The index matching material 4 improves the incidence efficiency of the light PL onto the light incident surface 72a of the light guide unit 71.

[0064] The light incident surface 72a of the light guide unit 71 does not overlap with the sealing material 120 when viewed from the Y-axis direction. The light incident surface 72a is not provided on the side of the sealing material 120. In the example shown, the light incident surface 72a overlaps with the second dustproof substrate 152 when viewed from the Y-axis direction. Although not shown, the light incident surface 72a may also overlap with the counter substrate 140 when viewed from the Y-axis direction.

[0065] As shown in FIG. 2, the photodetector 73 includes, for example, a photodetector section 74, a wavelength filter 75, and a support section .

[0066] When light BL is incident on the liquid crystal layer 130, the light detection unit 74 detects light PL emitted from the second surface 42b of the liquid crystal panel 42. The light detection unit 74 is, for example, a photodiode, a camera, or a spectrometer.

[0067] The wavelength filter 75 is provided between the light detecting unit 74 and the light exit surface 72b of the light guiding unit 71. The wavelength filter 75 is, for example, a wavelength cut filter that transmits the light PL and reduces the light BL. The wavelength filter 75 may also completely cut off the light BL.

[0068] The support portion 76 includes, for example, a light blocking body 77 and a fixing portion 78 .

[0069] The light shielding body 77 is a housing that houses the light detecting unit 74 and the wavelength filter 75. The light shielding body 77 can reduce stray light that enters the light detecting unit 74. The light exit surface 72b of the light guiding unit 71 is inserted into the light shielding body 77. The material of the light shielding body 77 is, for example, metal, resin, or the like.

[0070] The fixed portion 78 is connected to the light blocking body 77. A slot 78a is formed in the fixed portion 78. In the illustrated example, the slot 78a is formed along the X axis. For example, the light guide 73 is fixed to the housing 80 by a screw 79 inserted into the elongated hole 78a. In the X-axis direction, the length W1 of the elongated hole 78a is greater than the length W2 of the portion of the light guide 71 inserted into the light shield 77. Therefore, after the light detector 73 is temporarily attached to the housing 80, the light detector 73 can be inserted into the light detector 73 by moving the light detector 73 toward the light guide 71. This prevents unnecessary bending stress from being applied to the light guide 71, thereby preventing damage to the light guide 71. Therefore, the support 76 can be easily attached to the housing 80 while the other end of the light guide 71 is inserted into the light shield 77.

[0071] A connection cable 95 is connected to the photodetector 74 of the photodetector 70. The connection cable 95 passes through an opening 96 formed in a circuit board 94 and is connected to a connector 97. In the illustrated example, the circuit board 94 is provided with a detection signal processor 91 and a central controller 92. The circuit board 94 may be arranged, for example, so as to cover the cross dichroic prism 50 in FIG. 1 . Therefore, by passing the connection cable 95 through the opening 96, the connection cable 95 can be shortened and installation can be facilitated.

[0072] 1.4. Changes in LCD panel performance over time and photoluminescence FIG. 7 is a graph illustrating the change over time in photoluminescence when blue light is irradiated onto a liquid crystal layer. In FIG. 7, the horizontal axis represents the measured wavelength, and the vertical axis represents the radiant light intensity observed from the liquid crystal layer irradiated with blue light. The solid line L0 represents the initial spectrum when blue light begins to be irradiated onto the liquid crystal layer, and the dashed line L1 represents the spectrum after blue light has been irradiated for a certain period of time. It is assumed that the spectrum other than that corresponding to the incident light is due to photoluminescence from degradation substances generated in the liquid crystal layer. FIG. 7 and FIGS. 8 to 10, which will be described later, show cases where both blue light and photoluminescence are detected.

[0073] As shown in Figure 7, when blue light with an intensity peak near 450 nm is continuously irradiated onto a liquid crystal layer for a certain period of time, the intensity of the spectrum of the emitted light from the liquid crystal layer increases. In particular, the intensity of the wavelength band between 550 nm and 650 nm increases, and the emitted light is observed as light with an increased proportion of red components. When electrons transition between liquid crystal molecules, a certain amount of light is emitted, but if degradation substances are present due to photochemical reactions, etc., it is estimated that emitted light includes phosphorescence with a wavelength of 550 nm to 650 nm.

[0074] Figures 8 and 9 are graphs explaining the change over time of photoluminescence in the accelerated degradation test of a liquid crystal panel. Figure 8 shows the spectra at test times T0, T1, T2, T3, and T4, respectively. In Figure 8, the horizontal axis is the measurement wavelength, and the vertical axis is the intensity of the emitted light observed from the liquid crystal layer. Figure 9 shows the change over time of the emitted light intensity in the wavelength band from 500 nm to 650 nm. In Figure 9, the horizontal axis is the test time, and the vertical axis is the intensity of the emitted light in the wavelength range observed from the liquid crystal layer. Figure 9 shows the corresponding points of the test times T0, T1, T2, T3, and T4 shown in Figure 8. In the accelerated degradation test shown in Figures 8 and 9, blue light with a high light beam density was irradiated onto the liquid crystal panel, and the emitted light from the liquid crystal panel was observed from the light incident side.

[0075] Figure 10 is a graph explaining the electro-optical characteristics (V-T characteristics) of a liquid crystal panel. In Figure 10, the vertical axis indicates the transmittance, and the horizontal axis indicates the applied voltage to the liquid crystal layer of the liquid crystal panel. In Figure 10, the V-T curves of the liquid crystal panel corresponding to the test times T0, T3, and T4 are shown, respectively.

[0076] The main factor for the change over time of the emitted light intensity observed in the liquid crystal panel is the change over time of the photoluminescence intensity from the liquid crystal panel. The test time T0 indicates the initial state, and T0 < T1 < T2 < T3 < T4. Due to the irradiation with blue light, the spectrum of the emitted light due to photoluminescence The intensity of the spectrum increases. At test times T1 and T2, the photoluminescence intensity increases in the 500 nm to 650 nm band. At test times T3 and T4, the photoluminescence intensity increases further across the entire measurement wavelength range, with a significant increase in the 500 nm to 650 nm band. For example, test times T3 and T4 are 1.1 and 1.2 times longer than test time T2, respectively. The photoluminescence intensity at test times T3 and T4 is, for example, 1.5 and more than 3 times that at test time T2, respectively. The VT curve of the LCD panel at test time T3 shifts toward the dark side, and the VT curve of the LCD panel at test time T4 shifts toward the bright side, indicating a decrease in the display quality of the LCD panel. It can be seen that the LCD panel begins to deteriorate rapidly from test time T3. Therefore, the degree of deterioration of the liquid crystal panel can be determined from the change in the intensity of photoluminescence.

[0077] It is assumed that the increase in photoluminescence intensity from the LCD panel is due to an increase in the concentration of degrading substances in the liquid crystal layer. After test time T4, the degradation progresses further, and the LCD panel is no longer able to restore display quality even with correction, reaching the end of its lifespan. The end of life of the LCD panel is determined, for example, when the photoluminescence intensity I0 observed between test times T2 and T3 is detected, as shown in Figure 9. The photoluminescence intensity I0 can be set to a limit value I0 corresponding to the LCD panel.

[0078] Therefore, by detecting the intensity of photoluminescence emitted from the liquid crystal panel, it is possible to monitor the deterioration of the liquid crystal layer and the deterioration of the liquid crystal panel caused by the deterioration of the liquid crystal layer. When blue light is continuously irradiated onto the liquid crystal layer for a certain period of time, the light emitted from the liquid crystal panel also contains fluorescent light with a wavelength of 600 to 650 nm. Furthermore, the shorter the wavelength of light irradiated onto the liquid crystal layer, the more likely it is to undergo deterioration due to photochemical reactions, etc.

[0079] 1.5. Control Method Next, a control method for the display device 100 according to this embodiment will be described with reference to the drawings. Specifically, the process of the deterioration determination unit 93 of the display device 100 will be described. FIG. 11 is a flowchart for explaining the process of the deterioration determination unit 93.

[0080] The deterioration determination unit 93 starts processing when a signal to start processing is input via an operation unit (not shown). For example, a configuration may be adopted in which the signal to start processing is automatically issued when a predetermined time has elapsed since light emission from the light source device 10 began. Such a configuration can be realized by executing a program using a microcomputer or the like.

[0081] First, as shown in FIG. 11, the deterioration determination unit 93 performs a process of detecting light PL emitted from deterioration substances 132 in the liquid crystal layer 130 when blue light BL is irradiated onto the liquid crystal layer 130, via the photodetector 70 (step S1).

[0082] Next, the deterioration determination unit 93 performs a process of determining whether or not the intensity of the detected light PL exceeds a predetermined value (step S2). The predetermined value may be set in consideration of the limit value I0 shown in FIG.

[0083] If it is determined that the intensity of the light PL does not exceed the predetermined value ("NO" in step S2), the deterioration determination unit 93 returns the process to step S1. Then, steps S1 and S2 are repeated until it is determined in step S2 that the intensity of the light PL exceeds the predetermined value.

[0084] On the other hand, if it is determined that the intensity of the light PL exceeds the predetermined value ("YES" in step S2), the deterioration determination unit 93 performs a process of notifying the liquid crystal panel 42 that its life has expired (step S3 ). Specifically, the deterioration determination unit 93 performs a process of notifying the user that the liquid crystal panel 42 has reached the end of its lifespan or the expected period until the end of its lifespan. The means of notification is not particularly limited. For example, the user performs maintenance on the liquid crystal panel 42 after receiving the notification from the deterioration determination unit 93. The determination result may be recorded in a storage means (not shown) within the display device 100, or may be transmitted to a server on a network via a communication means (not shown) and recorded therein.

[0085] Then, the deterioration determining unit 93 ends the process.

[0086] If it is determined that the intensity of the light PL exceeds a predetermined value, the central control unit 92 may, for example, send a signal to the light source control unit 90 to reduce the output of the light source. In this way, the progression of deterioration of the liquid crystal panel 42 can be slowed, thereby ensuring ample time before maintenance by the user is required.

[0087] 1.6. Effects The display device 100 comprises an element substrate 110 as a first substrate and an opposing substrate 140 as a second substrate arranged opposite each other, and a liquid crystal layer 130 arranged between the element substrate 110 and the opposing substrate 140, a liquid crystal panel 42 having a first surface 42a facing in the normal direction and onto which light BL in a first wavelength range is incident, and a second surface 42b intersecting with the first surface 42a, and a light detection unit 74 that detects light PL in a wavelength range longer than the first wavelength range that is emitted from the second surface 42b when light BL in the first wavelength range is incident on the liquid crystal layer 130.

[0088] Therefore, in the display device 100, the amount of light BL in the first wavelength range incident on the light detection unit 74 can be reduced compared to when the light detection unit detects light PL in the long wavelength range emitted in the normal direction. More specifically, in a direction perpendicular to or obliquely viewing the first surface 42a, the intensity of the light BL reflected by the liquid crystal panel 42 is overwhelmingly greater than the intensity of the light PL. However, for light emitted from the second surface 42b, the intensity of the light PL is greater than the intensity of the light BL. This makes it easier to detect changes in the intensity of the light PL. Therefore, the degree of deterioration of the liquid crystal panel 42 can be accurately detected by observing the light PL emitted from the second surface 42b. Furthermore, the detection sensitivity of the light PL in the light detection unit 74 can be improved. This allows the degree of deterioration of the liquid crystal panel 42 to be accurately detected.

[0089] The display device 100 includes a light guide 71 that guides the light PL in the long wavelength range emitted from the second surface 42b to the light detection unit 74. Therefore, in the display device 100, the light detection unit 74 can efficiently detect the light PL in the long wavelength range.

[0090] The display device 100 includes a sealant 120 that connects the element substrate 110 and the counter substrate 140 and surrounds the liquid crystal layer 130, and the light incident surface 72a of the light guide unit 71 does not overlap with the sealant 120 when viewed from a direction perpendicular to the normal direction. Therefore, the display device 100 can prevent the long-wavelength light PL detected by the light detector 74 from being attenuated by passing through the sealant 120. Furthermore, there is no variation in the attenuation rate of the light PL due to manufacturing variations in the width of the sealant 120.

[0091] In the display device 100, the light incident surface 72a of the light guide 71 is provided on the short side Eb side of the display area E of the liquid crystal panel 42 when viewed from the normal direction. Therefore, in the display device 100, the long wavelength light PL emitted from the liquid crystal layer 130 can be detected by simply integrating it along the long side Ea, which is the longer of the long sides Ea and short sides Eb of the display area E. Therefore, the degree of deterioration of the liquid crystal panel 42 can be detected with high accuracy. Note that it is not prohibited to provide the light incident surface 72a of the light guide 71 on the long side Ea side of the display area E of the liquid crystal panel 42.

[0092] The display device 100 has an index matching material 4 disposed between the light incident surface 72a and the second surface 42b of the light guide 71. Therefore, the display device 100 can reduce reflection of light PL in the long wavelength range at the light incident surface 72a of the light guide 71. Furthermore, even if the second surface 42b has irregularities due to the manufacturing process, the index matching material 4 can reduce reflection due to the irregularities. Therefore, the light incident surface 72a of the light guide 71 can be positioned in a desired orientation.

[0093] The display device 100 includes a wavelength filter 75 that is provided between the photodetector 74 and the light exit surface 72b of the light guide 71 and that reduces the light BL in the first wavelength range. Therefore, the display device 100 can reduce the light BL in the first wavelength range that is incident on the photodetector 74. Therefore, the light PL caused by the degradation substances 132 generated in the liquid crystal layer 130 can be observed.

[0094] 2. Display Device Modifications 2.1. First variant Next, a display device according to a first modified example of this embodiment will be described with reference to the drawings. FIG. 12 is a cross-sectional view that schematically shows a display device 200 according to a first modified example of this embodiment. FIG. 13 is a side view that schematically shows a display device 200 according to a first modified example of this embodiment. For convenience, FIG. 12 omits illustration of components other than the liquid crystal panel 42, the light guide 71, and the index matching material 4. FIG. 13 omits illustration of components other than the liquid crystal panel 42 and the holder 46. In addition, FIGS. 12 and 13 illustrate the liquid crystal panel 42 in a simplified form.

[0095] Hereinafter, in the display device 200 according to the first modification of this embodiment, components having the same functions as the components of the display device 100 described above will be given the same reference numerals, and detailed description thereof will be omitted.

[0096] In the display device 100 described above, as shown in FIGS. 5 and 6, the light incident surface 72a and the through-hole 46c of the light guide section 71 overlap with the second dustproof substrate 152 when viewed from a direction perpendicular to the normal direction.

[0097] In contrast, in the display device 200, the light incident surface 72a of the light guide 71 overlaps with the first dustproof substrate 150 when viewed from a direction perpendicular to the normal direction, as shown in Fig. 12. The through-hole 46c overlaps with the first dustproof substrate 150 when viewed from a direction perpendicular to the normal direction, as shown in Fig. 13.

[0098] 12, light guide 71 is provided at an angle with respect to the X-axis direction. Light guide 71 is inclined so that light incident surface 72a faces liquid crystal layer 130. Light incident surface 72a of light guide 71 has a perpendicular line Q that intersects with liquid crystal layer 130. Therefore, in display device 200, light incident surface 72a of light guide 71 can take in light PL more efficiently than when the light incident surface does not have a perpendicular line that intersects with the liquid crystal layer.

[0099] 13, the second dustproof substrate 152 and the inner wall of the holder 46 are bonded together with a thermally conductive adhesive 6. As shown in FIG. 13, the thermally conductive adhesive 6 may find its way around the side surface of the second dustproof substrate 152. Therefore, by forming the through-hole 46c so as to overlap with the first dustproof substrate 150, the light PL can be efficiently incident on the light incident surface 72a of the light-guiding unit 71 without being affected by the thermally conductive adhesive 6.

[0100] 2.2. Second Variant Next, a display device according to a second modification of this embodiment will be described with reference to the drawings. Fig. 14 shows a light modulation device 40B and a light modulation device 300 according to the second modification of this embodiment. FIG. 15 is a diagram schematically illustrating a detection device 70. FIG. 15 is a side view schematically illustrating a display device 300 according to a second modified example of the present embodiment. For convenience, FIG. 15 omits illustration of components other than the liquid crystal panel 42 and the holder 46. FIG. 15 also illustrates a simplified version of the liquid crystal panel 42.

[0101] Hereinafter, in the display device 300 according to the second modification of this embodiment, components having the same functions as the components of the display devices 100 and 200 described above will be given the same reference numerals, and detailed description thereof will be omitted.

[0102] 2 and 6, the display device 100 described above is provided with only one light guide section 71. Furthermore, only one through-hole 46c is formed.

[0103] In contrast to this, display device 300 is provided with a plurality of light guide sections 71, as shown in Figures 14 and 15. Furthermore, a plurality of through holes 46c are formed.

[0104] 14, three light guiding units 71 are provided, but the number is not particularly limited. By providing a plurality of light guiding units 71, the detection sensitivity of light PL in light detecting unit 74 can be improved.

[0105] A reflector 377 is provided on the inner wall of the light blocking body 77 of the support unit 76. The reflector 377 is made of a metal such as aluminum. The reflector 377 reflects the light PL emitted from the light emitting surface 72b of the light guide 71. Therefore, the component of the light PL emitted from the light emitting surface 72b that is not directly directed toward the light detecting unit 74 can be reflected by the reflector 377 and reach the light detecting unit 74.

[0106] Three through holes 46c are formed, corresponding to the number of light guiding sections 71. As with the display device 200 described above, in the display device 300, the through holes 46c overlap with the first dustproof substrate 150 when viewed from a direction perpendicular to the normal direction. The second dustproof substrate 152 is adhered to the inner wall of the holder 46 via a thermally conductive adhesive 6.

[0107] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0108] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations that replace non-essential parts of the configurations described in the embodiments. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations that add publicly known technology to the configurations described in the embodiments.

[0109] The following can be derived from the above-described embodiment and modifications.

[0110] One aspect of the display device is a liquid crystal panel including a first substrate and a second substrate disposed opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal panel having a first surface oriented in a normal direction of the first substrate and onto which light in a first wavelength range is incident, and a second surface intersecting the first surface; a light detection unit that detects light in a wavelength range longer than the first wavelength range that is emitted from the second surface when light in a first wavelength range is incident on the liquid crystal layer; It has.

[0111] According to this display device, the degree of deterioration of the liquid crystal panel can be detected with high accuracy.

[0112] In one aspect of the display device, The optical element may further include a light guide section that guides the light in the long wavelength range emitted from the second surface to the light detection section.

[0113] According to this display device, the light detecting section can efficiently detect light in the long wavelength range.

[0114] In one aspect of the display device, a sealant that connects the first substrate and the second substrate and surrounds the liquid crystal layer when viewed from the normal direction; When viewed from a direction perpendicular to the normal direction, the light incident surface of the light guide portion may not overlap with the sealing material.

[0115] According to this display device, it is possible to prevent the light in the long wavelength range detected by the light detection section from being attenuated by passing through the sealing material.

[0116] In one aspect of the display device, The light incident surface of the light guide section may have a perpendicular line that intersects with the liquid crystal layer.

[0117] According to this display device, the light incident surface of the light guide section can efficiently take in light in the long wavelength range.

[0118] In one aspect of the display device, When viewed from the normal direction, the light incident surface of the light guide section may be provided on a shorter side of a display area of ​​the liquid crystal panel.

[0119] According to this display device, light in the long wavelength region emitted from the liquid crystal layer can be detected by simply integrating it along the longer side of the long and short sides of the display area.

[0120] In one aspect of the display device, The light guide may include an index matching material disposed between the light incident surface of the light guide and the second surface.

[0121] According to this display device, it is possible to reduce reflection of light in the long wavelength range on the light incident surface of the light guide section.

[0122] In one aspect of the display device, The light source may further include a wavelength filter provided between the light detecting section and the light emitting surface of the light guiding section, the wavelength filter reducing light in the first wavelength range.

[0123] According to this display device, it is possible to reduce the light in the first wavelength range that is incident on the photodetector.

[0124] One aspect of the control method for a display device includes: A method for controlling a display device having a liquid crystal panel including a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel having a first surface oriented in a normal direction of the first substrate and onto which light in a first wavelength range is incident, and a second surface intersecting with the first surface, the method comprising: A display device control method for detecting light in a wavelength range longer than the first wavelength range that is emitted from the second surface when light in a first wavelength range is incident on the liquid crystal layer.

[0125] According to this control method for a display device, the degree of deterioration of the liquid crystal panel can be detected with high accuracy. [Explanation of symbols]

[0126] 2...screen, 4...index matching material, 6...thermal conductive adhesive, 10...light source device, 20, 22...dichroic mirror, 24, 26, 28...reflection mirror, 30, 32, 34, 36, 38...relay lens, 40R, 40G, 40B...light modulation device, 41a...first polarizing element, 41b...second polarizing element, 42...liquid crystal panel, 42a...first surface, 42b...second surface, 44...COF, 44a...drive moving IC, 44b...connector, 46...holder, 46a...opening, 46b...bolt hole, 46c...through hole, 50...cross dichroic prism, 60...projection optical system, 62, 64, 66...lens, 70...light detection device, 71...light guide section, 71a...core, 71b...clad, 72a...light incident surface, 72b...light exit surface, 73...photodetector, 74...light detection section, 75...wavelength filter, 76...support section, 77 ...light shielding body, 78...fixing portion, 78a...long hole, 79...screw, 80...casing, 90...light source control portion, 91...detection signal processing portion, 92...central control portion, 93...deterioration determination portion, 94...circuit board, 95...connection cable, 96...opening, 97...connector, 100...display device, 101...external connection terminal, 102...data line driving circuit, 103...inspection circuit, 104...scanning line driving circuit, 105...first wiring, 106...second wiring Line, 110...element substrate, 112...first support substrate, 114...pixel electrode, 116...TFT, 118...first alignment layer, 120...sealing material, 130...liquid crystal layer, 132...deterioration substance, 140...counter substrate, 141...second support substrate, 142...partition portion, 143...insulating layer, 144...counter electrode, 145...second alignment layer, 150...first dustproof substrate, 152...second dustproof substrate, 200, 300...display device, 377...reflective material

Claims

1. a liquid crystal panel including a first substrate and a second substrate disposed opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal panel having a first surface oriented in a normal direction of the first substrate and onto which light in a first wavelength range is incident, and a second surface intersecting the first surface; a light detection unit that detects light in a wavelength range longer than the first wavelength range that is emitted from the second surface when light in a first wavelength range is incident on the liquid crystal layer; A display device having:

2. In claim 1, a light guide section that guides the light in the long wavelength range emitted from the second surface to the light detection section.

3. In claim 2, a sealant that connects the first substrate and the second substrate and surrounds the liquid crystal layer when viewed from the normal direction; a light incident surface of the light guide portion that does not overlap with the sealing material when viewed from a direction perpendicular to the normal direction.

4. In claim 3, A display device, wherein a light incident surface of the light guide portion has a perpendicular line intersecting with the liquid crystal layer.

5. In claim 2, A display device, wherein the light incident surface of the light guide section is provided on a shorter side of a display area of ​​the liquid crystal panel when viewed from the normal direction.

6. In claim 2, A display device comprising an index matching material disposed between the light incident surface of the light guide and the second surface.

7. In claim 2, A display device comprising: a wavelength filter provided between the light detection unit and the light exit surface of the light guide unit, the wavelength filter reducing light in the first wavelength range.

8. A method for controlling a display device having a liquid crystal panel including a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel having a first surface oriented in a normal direction of the first substrate and onto which light in a first wavelength range is incident, and a second surface intersecting with the first surface, the method comprising: A display device control method comprising: detecting, when light in a first wavelength range is incident on the liquid crystal layer, light in a wavelength range longer than the first wavelength range that is emitted from the second surface.

Images